KNOWLEDGE HUB

IN VIRTO FERTILISATION

2012-03-07T09:29:00.002-08:00

In vitro fertilisation

"Naked" Egg

Oocyte with surrounding granulosa cells

In vitro fertilisation (IVF) is a process by which egg cells are fertilised by sperm outside the body: in vitro. IVF is a major treatment in infertility when other methods of assisted reproductive technology have failed. The process involves hormonally controlling the ovulatory process, removing ova (eggs) from the woman's ovaries and letting sperm fertilise them in a fluid medium. The fertilised egg (zygote) is then transferred to the patient's uterus with the intent to establish a successful pregnancy. The first successful birth of a "test tube baby", Louise Brown, occurred in 1978. Robert G. Edwards, the physiologist who developed the treatment, was awarded the Nobel Prize in Physiology or Medicine in 2010.

The term in vitro, from the Latin meaning in glass, is used, because early biological experiments involving cultivation of tissues outside the living organism from which they came, were carried out in glass containers such as beakers, test tubes, or petri dishes. Today, the term in vitro is used to refer to any biological procedure that is performed outside the organism it would normally be occurring in, to distinguish it from an in vivo procedure, where the tissue remains inside the living organism within which it is normally found. A colloquial term for babies conceived as the result of IVF, "test tube babies", refers to the tube-shaped containers of glass or plastic resin, called test tubes, that are commonly used in chemistry labs and biology labs. However, in vitro fertilisation is usually performed in the shallower containers called Petri dishes. One IVF method, Autologous Endometrial Coculture, is actually performed on organic material, but is still considered in vitro.

Indications

IVF may be used to overcome female infertility in the woman due to problems of the fallopian tube, making fertilisation in vivo difficult. It may also assist in male infertility, where there is defect sperm quality, and in such cases intracytoplasmic sperm injection (ICSI) may be used, where a sperm cell is injected directly into the egg cell. This is used when sperm have difficulty penetrating the egg, and in these cases the partner's or a donor's sperm may be used. ICSI is also used when sperm numbers are very low. ICSI results in success rates equal to those of IVF.

For IVF to be successful it typically requires healthy ova, sperm that can fertilise, and a uterus that can maintain a pregnancy. Due to the costs of the procedure, IVF is generally attempted only after less expensive options have failed.

IVF can also be used with egg donation or surrogacy where the woman providing the egg isn't the same who will carry the pregnancy to term. This means that IVF can be used for females who have already gone through menopause. The donated oocyte can be fertilised in a crucible. If the fertilisation is successful, the embryo will be transferred into the uterus, within which it may implant.

IVF can also be combined with preimplantation genetic diagnosis (PGD) to rule out presence of genetic disorders. A similar but more general test has been developed called Preimplantation Genetic Haplotyping

Method

Theoretically, in vitro fertilisation could be performed by collecting the contents from a woman's fallopian tubes or uterus after natural ovulation, mixing it with semen, and reinserting into the uterus. However, without additional techniques, the chances of pregnancy would be extremely small. Such additional techniques that are routinely used in IVF include ovarian hyperstimulation to retrieve multiple eggs, ultrasound-guided transvaginal oocyte retrieval directly from the ovaries, egg and sperm preparation, as well as culture and selection of resultant embryos before embryo transfer back into the uterus.

Ovarian hyperstimulation

There are two main protocols for stimulating the ovaries for IVF treatment. The long protocol involves downregulation (suppression or exhaustion) of the pituitary ovarian axis by the prolonged use of a GnRH agonist. Subsequent ovarian hyperstimulation, typically using follicle stimulating hormone (FSH), starts once the process of downregulation is complete, generally after 10 to 14 days.

The short protocol skips the downregulation part, and consists of a regimen of fertility medications to stimulate the development of multiple follicles of the ovaries. In most patients, injectable gonadotropins (usually FSH analogues) are used under close monitoring. Such monitoring frequently checks the estradiol level and, by means of gynecologic ultrasonography, follicular growth. Typically approximately 10 days of injections will be necessary. Spontaneous ovulation during the cycle is typically prevented by the use of GnRH antagonists that are used just during the last days of stimulation to block the natural surge of luteinising hormone (LH) and allow the physician to start the ovulation process by using medication, usually injectable human chorionic gonadotropins.

Ovarian stimulation carries the risk of excessive stimulation. This complication is life-threatening and ovarian stimulation using gonadotropins must only be carried out under strict medical supervision.

Egg retrieval

When the ovarian follicles have reached a certain degree of development, final maturation is induced, generally by an injection of human chorionic gonadotropin (hCG). Commonly, this is known as the "trigger shot." hCG acts as an analogue of luteinising hormone, and ovulation would occur between 38 and 40 hours after a single HCG injection, but the egg retrieval is performed at a time usually between 34 and 36 hours after hCG injection, that is, just prior to when the follicles would rupture. This avails for scheduling the egg retrieval procedure at a time where the eggs are fully mature. HCG injection confers a risk of ovarian hyperstimulation syndrome. Using a GnRH agonist instead of hCG eliminates the risk of ovarian hyperstimulation syndrome, but with a delivery rate of approximately 6% less than with hCG.

The eggs are retrieved from the patient using a transvaginal technique called transvaginal oocyte retrieval, involving an ultrasound-guided needle piercing the vaginal wall to reach the ovaries. Through this needle follicles can be aspirated, and the follicular fluid is handed to the IVF laboratory to identify ova. It is common to remove between ten and thirty eggs. The retrieval procedure takes about 20 minutes and is usually done under conscious sedation or general anaesthesia.

Egg and sperm preparation

In the laboratory, the identified eggs are stripped of surrounding cells and prepared for fertilisation. An oocyte selection may be performed prior to fertilisation to select eggs with optimal chances of successful pregnancy. In the meantime, semen is prepared for fertilisation by removing inactive cells and seminal fluid in a process called sperm washing. If semen is being provided by a sperm donor, it will usually have been prepared for treatment before being frozen and quarantined, and it will be thawed ready for use.

Fertilisation

The sperm and the egg are incubated together at a ratio of about 75,000:1 in the culture media for about 18 hours. In most cases, the egg will be fertilised by that time and the fertilised egg will show two pronuclei. In certain situations, such as low sperm count or motility, a single sperm may be injected directly into the egg using intracytoplasmic sperm injection (ICSI). The fertilised egg is passed to a special growth medium and left for about 48 hours until the egg consists of six to eight cells.

In gamete intrafallopian transfer, eggs are removed from the woman and placed in one of the fallopian tubes, along with the man's sperm. This allows fertilisation to take place inside the woman's body. Therefore, this variation is actually an in vivo fertilisation, not an in vitro fertilisation.

Embryo culture

Typically, embryos are cultured until having reached the 6–8 cell stage three days after retrieval. In many Canadian, American and Australian programmeshowever, embryos are placed into an extended culture system with a transfer done at the blastocyst stage at around five days after retrieval, especially if many good-quality embryos are still available on day 3. Blastocyst stage transfers have been shown to result in higher pregnancy rates. In Europe, transfers after 2 days are common.

Culture of embryos can either be performed in an artificial culture medium or in an autologous endometrial coculture (on top of a layer of cells from the woman's own uterine lining). With artificial culture medium, there can either be the same culture medium throughout the period, or a sequential system can be used, in which the embryo is sequentially placed in different media. For example, when culturing to the blastocyst stage, one medium may be used for culture to day 3, and a second medium is used for culture thereafter. Single or sequential medium are equally effective for the culture of human embryos to the blastocyst stage. Artificial embryo culture media basically contain glucose, pyruvate, and energy-providing components, but addition of amino acids, nucleotides, vitamins, and cholesterol improve the performance of embryonic growth and development. Methods to permit dynamic embryo culture with fluid flow and embryo movement are also available. A new method in development uses the uterus as an incubator and the naturally occurring intrauterine fluids as culture medium by encapsulating the embryos in permeable intrauterine vessel.

Embryo selection

Laboratories have developed grading methods to judge oocyte and embryo quality. In order to optimise pregnancy rates, there is significant evidence that a morphological scoring system is the best strategy for the selection of embryos. However, presence of soluble HLA-G might be considered as a second parameter if a choice has to be made between embryos of morphologically equal quality. Also, two-pronuclear zygotes (2PN) transitioning through 1PN or 3PN states tend to develop into poorer-quality embryos than those that constantly remain 2PN.

More advanced methods of embryo profiling may also be performed in order to optimise embryo selection, as further described in the "expansions"-section below.

Embryo transfer

Embryos are failed by the embryologist based on the amount of cells, evenness of growth and degree of fragmentation. The number to be transferred depends on the number available, the age of the woman and other health and diagnostic factors. In countries such as Canada, the UK, Australia and New Zealand, a maximum of two embryos are transferred except in unusual circumstances. In the UK and according to HFEA regulations, a woman over 40 may have up to three embryos transferred, whereas in the USA, younger women may have many embryos transferred based on individual fertility diagnosis. Most clinics and country regulatory bodies seek to minimise the risk of pregnancies carrying multiples. As it is not uncommon for more implantations to take than desired, the next step faced by the expectant mother is that of selective abortion. The embryos judged to be the "best" are transferred to the patient's uterus through a thin, plastic catheter, which goes through her vagina and cervix. Several embryos may be passed into the uterus to improve chances of implantation and pregnancy.

Success rates

IVF success rates are the percentage of all IVF procedures which result in a favorable outcome. Depending on the type of calculation used, this outcome may represent the number of confirmed pregnancies, called the pregnancy rate or number of live births, called the live birth rate.

Due to advancement in reproductive technology, the IVF success rates are substantially better today than they were just a few years ago. The most current data available in the United States a 2009 summary complied by the Society for Reproductive Medicine (SART) which reports the average national IVF success rates per age group using non-donor eggs (see table below).

	<35	35-37	38-40	41-42
Pregnancy Rate	47.6	38.9	30.1	20.5
Live Birth Rate	41.4	31.7	22.3	12.6

The live birth rates using donor eggs are also given by the SART and include all age groups using either fresh or thawed eggs.

	Fresh Donor Egg Embryos	Thawed Donor Egg Embryos
Live Birth Rate	55.1	33.8

In 2006, Canadian clinics reported an average pregnancy rate of 35%. A French study estimated that 66% of patients starting IVF treatment finally succeed in having a child (40% during the IVF treatment at the center and 26% after IVF discontinuation). Achievement of having a child after IVF discontinuation was mainly due to adoption (46%) or spontaneous pregnancy (42%).

Live birth rate

The live birth rate is the percentage of all IVF cycles that lead to a live birth. This rate does not include miscarriage or stillbirth and multiple-order births such as twins and triplets are counted as one pregnancy. The live birth rate is calculated as follows:

Number of live births ÷ Number of procedures performed (cycle start, egg retrieval or embryo transfer)

In 2006, Canadian clinics reported a live birth rate of 27%. Birth rates in younger patients were slightly higher, with a success rate of 35.3% for those 21 and younger, the youngest group evaluated. Success rates for older patients were also lower and decrease with age, with 37-year-olds at 27.4% and no live births for those older than 48, the oldest group evaluated. Some clinics exceeded these rates, but it is impossible to determine if that is due to superior technique or patient selection, because it is possible to artificially increase success rates by refusing to accept the most difficult patients or by steering them into oocyte donation cycles (which are compiled separately). Further, pregnancy rates can be increased by the placement of several embryos at the risk of increasing the chance for multiples.

Because not each IVF cycle that is started will lead to oocyte retrieval or embryo transfer, reports of live birth rates need to specify the denominator, namely IVF cycles started, IVF retrievals, or embryo transfers. The Society for Assisted Reproductive Technology (SART) summarised 2008-9 success rates for US clinics for fresh embryo cycles that did not involve donor eggs and gave live birth rates by the age of the prospective mother, with a peak at 41.3% per cycle started and 47.3% per embryo transfer for patients under 35 years of age.

IVF attempts in multiple cycles result in increased cumulative live birth rates. Depending on the demographic group, one study reported 45% to 53% for three attempts, and 51% to 71% to 80% for six attempts.

Pregnancy rate

Pregnancy rate may be defined in various ways. In the United States, the pregnancy rate used by the Society for Assisted Reproductive Technology and the Centers for Disease Control (and appearing in the table in the Success Rates section above) are based on fetal heart motion observed in ultrasound examinations. However, some clinics may advertise pregnancy rates based on pregnancy tests which are less definitive, such as urine or blood tests for hCG. This is the rate most often published by fertility clinics because often at the time of publishing not all IVF patients have given birth. The pregnancy rate is calculated as follows:

Number pregnancies / Number of procedures performed (cycle start, egg retrieval or embryo transfer)

Success or failure factors

The main potential factors that influence pregnancy (and live birth) rates in IVF have been suggested to be maternal age, duration of infertility or subfertility, bFSH and number of oocytes, all reflecting ovarian function. Optimal woman’s age is 23–39 years at time of treatment.

Stress

In a 2005 Swedish study, 166 women were monitored starting one month before their IVF cycles, and the results showed no significant correlation between psychological stress and IVF outcome. The study concluded with the recommendation to clinics that it might be possible to reduce the stress experienced by IVF patients during the treatment procedure by informing them of those findings. While psychological stress experienced during a cycle might not influence an IVF outcome, it is possible that the experience of IVF can result in stress that leads to depression. The financial consequences alone of IVF can influence anxiety and become overwhelming. However, for many couples, the alternative is infertility, and the experience of infertility itself can also cause extreme stress and depression.

Other factors

Other determinants of outcome of IVF include:

Tobacco smoking reduces the chances of IVF producing a live birth by 34% and increases the risk of an IVF pregnancy miscarrying by 30%.
A body mass index (BMI) over 27 causes a 33% decrease in likelihood to have a live birth after the first cycle of IVF, compared to those with a BMI between 20 and 27. Also, pregnant women who are obese have higher rates of congenital abnormality, miscarriage, gestational diabetes, hypertension, thromboembolism and problems during delivery. Ideal body mass index is 19–30.
Salpingectomy before IVF treatment increases chances for women with hydrosalpinges
Success with previous pregnancy and/or live birth increases chances
Low alcohol/caffeine intake increases success rate
Level of DNA fragmentation as measured e.g. by Comet assay, advanced maternal age and semen quality.
The number of embryos transferred in the treatment cycle.
Other factors of semen quality for the sperm provider.
Women with ovary-specific FMR1 genotypes including het-norm/low have significantly decreased pregnancy chances in IVF.
Some studies also suggest the autoimmune disease may also play a role in decreasing IVF success rates by interfering with proper implantation of the embryo after transfer.

Aspirin, however, was shown by a meta-analysis to not improve pregnancy rates after IVF.

Risks

Possible risks may occur throughout the procedure, but the risk you may encounter depend on the specific step of the procedure. During ovarian stimulation, hyperstimulation syndrome may occur. This results in swollen, painful ovaries and some form of it (mild, moderate or severe) occurs in 30% of patients. Mild cases can be treated with over the counter medications and cases can be resolved in the absence of pregnancy. In moderate cases, ovaries swell and fluid accumulated in the abdominal cavities and may have symptoms of heartburn, gas, nausea or loss of appetite. In severe cases patients have sudden excess abdominal pain, nausea, vomiting and will result in hospitalisation. During egg retrieval, there’s a small chance of bleeding, infection, and damage to surrounding structures like bowel and bladder (transvaginal ultrasound aspiration) as well as difficulty breathing, chest infection, allergic reactions to meds, or nerve damage (laproscopy). During embryo transfer, if more than one embryo is transferred there’s always a risk of multiple pregnancy, infertile couples may see this is good news but there may be risk to the embryos and to the mother such as premature delivery. Ectopic pregnancy may also occur if a fertilised egg develops outside the uterus, usually in the fallopian tubes and requires immediate destruction of the fetus.

Complications

Multiple Births

The major complication of IVF is the risk of multiple births. This is directly related to the practice of transferring multiple embryos at embryo transfer. Multiple births are related to increased risk of pregnancy loss, obstetrical complications, prematurity, and neonatal morbidity with the potential for long term damage. Strict limits on the number of embryos that may be transferred have been enacted in some countries (e.g. Britain, Belgium) to reduce the risk of high-order multiples (triplets or more), but are not universally followed or accepted. Spontaneous splitting of embryos in the womb after transfer can occur, but this is rare and would lead to identical twins. A double blind, randomised study followed IVF pregnancies that resulted in 73 infants (33 boys and 40 girls) and reported that 8.7% of singleton infants and 54.2% of twins had a birth weight of < 2,500 grams (5.5 lb).

However, despite the risks, some recent evidence suggests that twins conceived by IVF actually have a 40% decreased outcome risk for complications than spontaneous twin conceptions. Experts believe that this could be due to high level of prenatal monitoring received from the moment of conception.

Recent evidence also suggest that singleton offspring after IVF is at higher risk for lower birth weight for unknown reasons.

Birth defects

The issue of birth defects has been a controversial topic in IVF. Many studies do not show a significant increase after use of IVF, and some studies suggest higher rates for ICSI, whereas others do not support this finding. In 2008, an analysis of the data of the National Birth Defects Study in the US found that certain birth defects were significantly more common in infants conceived through IVF, notably septal heart defects, cleft lip with or without cleft palate, esophageal atresia, and anorectal atresia; the mechanism of causality is unclear.

A 2002 study, reviewing the birth records of all the IVF babies in Western Australia "has found IVF kids are twice as likely to have birth defects as normal births". The study allowed for the effects of multiple births and the mother's age. The higher incidence of birth defects "up to one year of age" included: heart defects, "chromosomal abnormalities like Down syndrome, spina bifida, gastro-intestinal abnormalities, musculo-skeletal, dislocated hips," and club feet. The IVF children also were found to have a higher incidence of lower birth weights, pre-term births, and cerebral palsy.

Japan's government prohibited the use of in vitro fertilisation procedures for couples in which both partners are infected with HIV. Despite the fact that the ethics committees previously allowed the Ogikubo, Tokyo Hospital, located in Tokyo, to use in vitro fertilisation for couples with HIV, the Ministry of Health, Labour and Welfare of Japan decided to block the practice. Hideji Hanabusa, the vice president of the Ogikubo Hospital, states that together with his colleagues, he managed to develop a method through which scientists are able to remove HIV from sperm.

Other Risks

Another risk of ovarian stimulation is the development of ovarian hyperstimulation syndrome, particularly if hCG is used to "trigger ovulation".

If the underlying infertility is related to abnormalities in spermatogenesis, it is plausible, but too early to examine that male offspring is at higher risk for sperm abnormalities.

Behavior and socioemotional functioning of children conceived by IVF is normal overall, according to studies on 9–18-year-old IVF children.

A negative pregnancy test after IVF is associated with an increased risk for depression in women, but not with any increased risk of developing anxiety disorders. Pregnancy test results do not seem to be a risk factor for depression or anxiety among men.

Expansions

There are various expansions or additional techniques that can be applied in IVF, which are usually not necessary for the IVF procedure itself, but would be virtually impossible or technically difficult to perform without concomitantly performing methods of IVF.

Embryo profiling

In addition to the methods already mentioned in the embryo selection above, there are more advanced techniques of embryo profiling that give more information to aid in the selection of the optimal embryo.

Also, methods are emerging in making comprehensive analyses of up to entire genomes, transcriptomes, proteomes and metabolomes which may be used to score embryos by comparing the patterns with ones that have previously been found among embryos in successful versus unsuccessful pregnancies:

In transcriptome evaluation, however, gene expression profiling studies of human embryos are limited due to legal and ethical issues. An alternative or complement is gene expression profiling of cumulus cells surrounding the oocyte and early embryo, or on granulosa cells. Profiling of cumulus cells can give valuable information regarding the efficiency of an ovarian hyperstimulation protocol, and may indirectly predict oocyte aneuploidy, embryo development and pregnancy outcomes, without having to perform any invasive procedure directly in the embryo.
Proteome profiling of embryos can indirectly be evaluated by sampling of proteins found in the vicinity of embryos, thereby providing a non-invasive method of embryo profiling. Examples of protein markers evaluated in such profiling include CXCL13 and granulocyte-macrophage colony-stimulating factor, where lower protein amounts are associated with higher implantation rates.

Another level of opportunity can be achieved by having the evaluation of the embryo profile tailored to the maternal status in regard to, for example health or immune status, potentially further detailed by similar profiling of the maternal genome, transcriptome, proteome and metabolome. Two examples of proteins that may be included in maternal profiling are endometrium-derived stathmin 1 and annexin A2, whose down- and up-regulation, respectively, are associated with higher rates of successful implantation.

The end-point of interest in the evaluation of an embryo profile is not necessarily the success rate of the pregnancy at hand, but may also be the health of the potential person as a child and adult in the future, such as in detection of inheritable diseases by preimplantation genetic diagnosis (PGD) or screening (PGS):

Preimplantation genetic screening or diagnosis (PGS or PGD)

Preimplantation genetic screening (PGS) or preimplantation genetic diagnosis (PGD) has been suggested to be able to be used in IVF to select an embryo that appears to have the greatest chances for successful pregnancy. However, a systematic review and meta-analysis of existing randomised controlled trials came to the result that there is no evidence of a beneficial effect of PGS as measured by live birth rate. On the contrary, for women of advanced maternal age, PGS significantly lowers the live birth rate. Technical drawbacks, such as the invasiveness of the biopsy, and non-representative samples because of mosaicism are the major underlying factors for inefficacy of PGS.

Still, as an expansion of IVF, patients who can benefit from PGS/PGD include:

Couples who have a family history of inherited disease
Couples who want to use gender selection to prevent a gender-linked disease
Couples who already have a child with an incurable disease and need compatible cells from a second healthy child to cure the first, resulting in a "saviour sibling" that matches the sick child in HLA type.

PGS screens for numeral chromosomal abnormalities while PGD diagnosis the specific molecular defect of the inherited disease. In both PGS and PGD, individual cells from a pre-embryo are analysed during the IVF process. Before the transfer of a pre-embryo back to a woman's uterus, one or two cells are removed from the pre-embryos (8-cell stage). These cells are then evaluated for normality. Typically within one to two days, following completion of the evaluation, only the normal pre-embryos are transferred back to the woman's uterus. In addition, PGS can reduce the risk of multiple pregnancies because fewer embryos are needed for implantation.

Cryopreservation

Cryopreservation can be performed as oocyte cryopreservation before fertilisation, or as embryo cryopreservation after fertilisation.

The Rand Consulting Group has estimated there to be 400,000 frozen embryos in the United States. The advantage is that patients who fail to conceive may become pregnant using such embryos without having to go through a full IVF cycle. Or, if pregnancy occurred, they could return later for another pregnancy. Spare oocytes or embryos resulting from fertility treatments may be used for oocyte donation or embryo donation to another woman or couple, and embryos may be created, frozen and stored specifically for transfer and donation by using donor eggs and sperm. Also, oocyte cryopreservation can be used for women who are likely to lose their ovarian reserve due to undergoing chemotherapy.

The outcome from using cryopreserved embryos has uniformly been positive with no increase in birth defects or development abnormalities.

Other expansions

Intracytoplasmic sperm injection (ICSI) is where a single sperm is injected directly into an egg. Its main usage as an expansion of IVF is to overcome male infertility problems, although it may also be used where eggs cannot easily be penetrated by sperm, and occasionally in conjunction with sperm donation. It can be used in teratozoospermia, since once the egg is fertilised abnormal sperm morphology does not appear to influence blastocyst development or blastocyst morphology.
Assisted zona hatching (AZH) can be performed shortly before the embryo is transferred to the uterus. A small opening is made in the outer layer surrounding the egg in order to help the embryo hatch out and aid in the implantation process of the growing embryo.
In egg donation and embryo donation, the resultant embryo after fertilisation is inserted in another woman than the one providing the eggs. These are resources for women with no eggs due to surgery, chemotherapy, or genetic causes; or with poor egg quality, previously unsuccessful IVF cycles or advanced maternal age. In the egg donor process, eggs are retrieved from a donor's ovaries, fertilised in the laboratory with the sperm from the recipient's partner, and the resulting healthy embryos are returned to the recipient's uterus.
Embryo splitting can be used for twinning to increase the number of available embryos.

Leftover embryos or eggs

There may be leftover embryos or eggs from IVF procedures if the woman for whom they were originally created has successfully carried one or more pregnancies to term. With the woman's or couple's permission, these may be donated to help other women or couples as a means of third party reproduction.

In embryo donation, these extra embryos are given to other couples or women for transfer with the goal of producing a successful pregnancy. The resulting child is considered the child of the woman who carries it and gives birth, and not the child of the donor, the same as occurs with egg donation or sperm donation.

Typically, genetic parents donate the eggs to a fertility clinic or embryo bank where they are preserved by oocyte cryopreservation or embryo cryopreservation until a carrier is found for them. Typically the process of matching the embryo(s) with the prospective parents is conducted by the agency itself, at which time the clinic transfers ownership of the embryos to the prospective parents.

In the United States, women seeking to be an embryo recipient undergo infectious disease screening required by the U.S. Food and Drug Administration (FDA), and reproductive tests to determine the best placement location and cycle timing before the actual Embryo Transfer occurs. The amount of screening the embryo has already undergone is largely dependent on the genetic parents' own IVF clinic and process. The embryo recipient may elect to have her own embryologist conduct further testing.

Alternatives to donating unused embryos are destroying them (or having them implanted at a time where pregnancy is very unlikely), keeping them frozen indefinitely, or donating them for use in research (with results in their unviability). Individual moral views on disposing leftover embryos may depend on personal views on the beginning of human personhood and definition and/or value of potential future persons and on the value that is given to fundamental research questions. Some people believe donation of leftover embryos for research is a good alternative to discarding the embryos when patients receive proper, honest and clear information about the research project, the procedures and the scientific values).

History

There was a transient biochemical pregnancy reported by Australian Foxton School researchers in 1953. John Rock was the first to extract an intact fertilised egg. The first pregnancy achieved through in vitro human fertilisation of a human oocyte was reported in The Lancet from the Monash University team in 1973, although it lasted only a few days and would today be called a biochemical pregnancy. There was also an ectopic pregnancy reported by Patrick Steptoe and Robert Edwards in 1976. In 1977, Steptoe and Edwards successfully carried out a pioneering conception which resulted in the birth of the world's first baby to be conceived by IVF, Louise Brown on 25 July 1978, in Oldham General Hospital, Greater Manchester, UK.

In October 1978, it was reported that Subash Mukhopadyay, a relatively unknown physician from Kolkata, India was performing experiments on his own with primitive instruments and a household refrigerator and this resulted in a test tube baby, later named as "Durga" (alias Kanupriya Agarwal) who was born on October 3, 1978 However, state authorities prevented him from presenting his work at scientific conferences and, in the absence of scientific evidence, his work is not recognised by the international scientific community.

Steptoe and Edwards were responsible for the world’s second (confirmed) baby conceived by IVF, Alastair MacDonald born on 14 January 1979 in Glasgow. A team led by Ian Johnston and Alex Lopata were responsible for Australia’s first baby conceived by IVF, Candice Reed born on 23 June 1980 in Melbourne. It was the subsequent use of stimulated cycles with clomiphene citrate and the use of human chorionic gonadotrophin (hCG) to control and time oocyte maturation, thus controlling the time of collection, that converted IVF from a research tool to a clinical treatment.

This was followed by a total of 14 pregnancies resulting in nine births in 1981 with the Monash University team. The Jones teamat the Eastern Virginia Medical School in Norfolk, Virginia, further improved stimulated cycles by incorporating the use of a follicle-stimulating hormone (uHMG). This then became known as controlled ovarian hyperstimulation (COH). Another step forward was the use of gonadotrophin-releasing hormone agonists (GnRHA), thus decreasing the need for monitoring by preventing premature ovulation, and more recently gonadotrophin-releasing hormone antagonists (GnRH Ant), which have a similar function. The additional use of the oral contraceptive pill has allowed the scheduling of IVF cycles, which has made the treatment far more convenient for both staff and patients.

The ability to freeze and subsequently thaw and transfer embryos has significantly improved the feasibility of IVF use. The other very significant milestone in IVF was the development of the intracytoplasmic sperm injection (ICSI) of single sperms by André van Steirteghem in Brussels, 1992. This has enabled men with minimal sperm production to achieve pregnancies. ICSI is sometimes used in conjunction with sperm recovery, using a testicular fine needle or open testicular biopsy. Using this method, some men with Klinefelter's syndrome, and so would be otherwise infertile, have occasionally been able to achieve pregnancy. Thus, IVF has become the final solution for most fertility problems, moving from tubal disease to male factor, idiopathic subfertility, endometriosis, advanced maternal age, and anovulation not responding to ovulation induction.

Robert Edwards was awarded the 2010 Nobel Prize in Physiology or Medicine "for the development of in vitro fertilization". Carl Wood was dubbed "the father of IVF (in vitro fertilisation)" for having pioneered the use of frozen embryos.

In the US, ART cycles started in 2006 resulted in 41,343 births (54,656 infants), which is slightly more than 1% of total US births.

Ethics

Issues

In a few cases, laboratory mix-ups (misidentified gametes, transfer of wrong embryos) have occurred, leading to legal action against the IVF provider and complex paternity suits. An example is the case of a woman in California who received the embryo of another couple and was notified of this mistake after the birth of her son. This has led to many authorities and individual clinics implementing procedures to minimise the risk of such mix-ups. The HFEA, for example, requires clinics to use a double witnessing system, where the identity of specimens is checked by two people at each point at which specimens are transferred. Alternatively, technological solutions are gaining favour, to reduce the manpower cost of manual double witnessing, and to further reduce the risk of human error. Technological solutions typically involve tagging individual specimen containers with uniquely numbered RFID tags which can be identified by readers connected to a computer. The computer tracks specimens throughout the process and alerts the embryologist if non-matching specimens are identified.

Another concern is that people will screen in or out for particular traits, using preimplantation genetic diagnosis. For example, a deaf British couple, Tom and Paula Lichy, have petitioned to create a deaf baby using IVF. Some medical ethicists have been very critical of this approach. Jacob Appel wrote that "intentionally culling out blind or deaf embryos might prevent considerable future suffering, while a policy that allowed deaf or blind parents to select for such traits intentionally would be far more troublesome."

Current state of the industry

Many people do not oppose the IVF practice itself (ie. the creating of a pregnancy through "artificial" ways) but are highly critical of the current state of the present day industry. Such individuals argue that the industry has now become a multi-billion industry, which is widely unregulated and prone to serious abuses in the desire of practitioners to obtain profit. For instance, in 2008, a California physician transferred 12 embryos to a woman who gave birth to octuplets (see Suleman octuplets). This has made international news, and had led to accusations that many doctors are willing to seriously endanger the health and even life of women in order to gain money. Robert Winston, professor of fertility studies at Imperial College London, had called the industry "corrupt" and "greedy" saying that "One of the major problems facing us in healthcare is that IVF has become a massive commercial industry," and that "What has happened, of course, is that money is corrupting this whole technology", and accused authorities of failing to protects couples from exploitation "The regulatory authority has done a consistently bad job. It's not prevented the exploitation of women, it's not put out very good information to couples, it's not limited the number of unscientific treatments people have access to".The industry has been accused of making unscientific claims, and distorting facts relating to infertility, in particular through widely exaggerated claims about how common infertility is in society, in an attempt to get as many couples as possible and as soon as possible to try treatments (rather than trying to conceive naturally for a longer time). Indeed, there are serious concerns about the overuse of treatments, for instance Dr. Sami David, a fertility specialist and one of the pioneers of the early days of the IVF treatments, has expressed disappointment over the current state of the industry, and said many procedures are unnecessary; he said: "It's being the first choice of treatment rather than the last choice. When it was first opening up in late 1970s, early 80s, it was meant to be the last resort. Now it's a first resort. I think that's an injustice to women. I also think it can harm women in the long run."

Pregnancy past menopause

Although menopause is a natural barrier to further conception, IVF has allowed women to be pregnant in their fifties and sixties. Women whose uterus has been appropriately prepared receive embryos that originated from an egg of an egg donor. Therefore, although these women do not have a genetic link with the child, they have an emotional link through pregnancy and childbirth. In many cases the genetic father of the child is the woman's partner. Even after menopause the uterus is fully capable of carrying out a pregnancy.

Same-sex couples, single and unmarried parents

A 2009 statement from the ASRM found no persuasive evidence that children are harmed or disadvantaged solely by being raised by single parents, unmarried parents, or homosexual parents. It did not support restricting access to assisted reproductive technologies on the basis of a prospective parent's marital status or sexual orientation.

Ethical concerns include reproductive rights, the welfare of offspring, nondiscrimination against unmarried individuals, homosexual, and professional autonomy.

A recent controversy in California focused on the question of whether physicians opposed to same-sex relationships should be required to perform IVF for a lesbian couple. Guadalupe T. Benitez, a medical assistant from San Diego, sued doctors Christine Brody and Douglas Fenton of the North Coast Women's Care Medical Group after Brody told her that she had "religious-based objections to treating homosexuals to help them conceive children by artificial insemination," and Fenton refused to authorise a refill of her prescription for the fertility drug Clomid on the same grounds. The California Medical Association had initially sided with Brody and Fenton, but the case, North Coast Women's Care Medical Group v. Superior Court, was decided unanimously by the California State Supreme Court in favor of Benitez on August 19, 2008.

Nadya Suleman came to international attention after having twelve embryos implanted, eight of which survived, resulting in eight newborns being added to her existing six-child family. The Medical Board of California sought to have fertility doctor Michael Kamrava, who treated Suleman, stripped of his license. State officials allege that performing Suleman's procedure is evidence of unreasonable judgment, substandard care, and a lack of concern for the eight children she would conceive and the six she was already struggling to raise. On June 1, 2011 the Medical Board issued a ruling that Kamrava's medical license be revoked effective July 1, 2011. [1]

Catholic objections

The Catholic Church opposes all kinds of in vitro fertilisation because, as with contraception, it separates the procreative purpose of the marriage act from its unitive purpose:

This particular doctrine, often expounded by the magisterium of the Church, is based on the inseparable connection, established by God, which man on his own initiative may not break, between the unitive significance and the procreative significance which are both inherent to the marriage act.

The reason is that the fundamental nature of the marriage act, while uniting husband and wife in the closest intimacy, also renders them capable of generating new life—and this as a result of laws written into the actual nature of man and of woman. And if each of these essential qualities, the unitive and the procreative, is preserved, the use of marriage fully retains its sense of true mutual love and its ordination to the supreme responsibility of parenthood to which man is called. We believe that our contemporaries are particularly capable of seeing that this teaching is in harmony with human reason.

According to the Catechism of the Catholic Church,

Techniques involving only the married couple (homologous artificial insemination and fertilization) are perhaps less reprehensible, yet remain morally unacceptable. They dissociate the sexual act from the procreative act. The act which brings the child into existence is no longer an act by which two persons give themselves to one another, but one that "entrusts the life and identity of the embryo into the power of doctors and biologists and establishes the domination of technology over the origin and destiny of the human person. Such a relationship of domination is in itself contrary to the dignity and equality that must be common to parents and children."

The Catholic Church maintains that it is not objectively evil to be infertile, and advocates adoption as an option for such couples who still wish to have children:

The Gospel shows that physical sterility is not an absolute evil. Spouses who still suffer from infertility after exhausting legitimate medical procedures should unite themselves with the Lord's Cross, the source of all spiritual fecundity. They can give expression to their generosity by adopting abandoned children or performing demanding services for others.

Gamete Intrafallopian Transfer (GIFT) is not technically in vitro fertilisation because with GIFT, fertilisation takes place inside the body, not on a Petri dish. The Catholic Church nevertheless is concerned with it because "Some theologians consider this to be a replacement of the marital act, and therefore immoral."

Availability and utilisation

In the USA, overall availability of IVF in 2005 was 2.5 IVF physicians per 100,000 population, and utilisation was 236 IVF cycles per 100,000. Utilisation highly increases with availability and IVF insurance coverage, and to a significant extent also with percentage of single persons and median income.

The cost of IVF rather reflects the costliness of the underlying healthcare system than the regulatory or funding environment, and ranges, on average for a standard IVF cycle and in 2006 United States dollars, between $12,500 in the United States to $4,000 in Japan. In Ireland, IVF costs around €4,000, with fertility drugs, if required, costing up to €3,000. The cost per live birth is highest in the United States ($41,000) and United Kingdom ($40,000) and lowest in Scandinavia and Japan (both around $24,500).

Many fertility clinics in the United States limit the upper age at which women are eligible for IVF to 50 or 55 years. These cut-offs make it difficult for women older than fifty-five to utilise the procedure.

In Australia, the average age of women undergoing ART treatment is 35.5 years among those using their own eggs (one in four being 40 or older) and 40.5 years among those using donated eggs.

Legal status

Government agencies in China passed bans on the use of IVF in 2003 by unmarried women or by couples with certain infectious diseases. Sunni Muslim nations generally allow IVF between married couples when conducted with their own respective sperm and eggs, but not with donor eggs from other couples. But Iran, which is Shi'a Muslim, has a more complex scheme. Iran bars sperm donation but allows donation of both fertilised and unfertilised eggs. Fertilised eggs are donated from married couples to other married couples, while unfertilised eggs are donated in the context of mut'ah or temporary marriage to the father. The nation of Costa Rica has a complete ban on all IVF technology, it having been ruled unconstitutional by the nation's Supreme Court because it "violated life." Costa Rica is the only country in the western hemisphere that forbids this technique. The Inter-American Court on Human Rights ruled out that the Costa Rican government has violated the human rights of infertile couples when it banned the use of this technique. According to the rule, Costa Rica had to enact legislation allowing the use of this type of procedure. The Court set a first dateline on February 2011 for a report on the question by the Costa Rican government. The latter missed the dateline and new datelines were set. All of them have been missed by the Costa Rican government. A law project sent reluctantly by the government of Pres. Laura Chinchilla was rejected at the Costa Rican parliament. Consequently, observers expect that Costa Rica will not abide to the request of the Inter-American Court on Human Rights. President Chinchilla, whose strong Catholic views have won her to be named officially as Preferred Daughter of the Virgin Mary has not publicly stated her position on the question of in vitro fertilisation. However, given the massive influence of the Catholic Church in her government any change in the status quo seems very unlikely La Costa Rica católica se atasca con la fertilización in vitroCIDH Extends Deadline For Approval Of Law For In-Vitro Fertilization In Costa Rica. Federal regulations in the United States include screening requirements and restrictions on donations, but generally do not affect sexually intimate partners. However, doctors may be required to provide treatments due to nondiscrimination laws, as for example in California.

All major restrictions on single but infertile women using IVF were lifted in Australia in 2002 after a final appeal to the Australian High Court was rejected on procedural grounds in the Leesa Meldrum case. A Victorian federal court had ruled in 2000 that the existing ban on all single women and lesbians using IVF constituted sex discrimination. Victoria's government announced changes to its IVF law in 2007 eliminating remaining restrictions on fertile single women and lesbians, leaving South Australia as the only state maintaining them. The US state of Tennessee proposed a bill in 2009 that would have defined donor IVF as adoption. During the same session another bill proposed barring adoption from any unmarried and cohabitating couple, and activist groups stated that passing the first bill would effectively stop unmarried people from using IVF. Neither of these bills passed.

World Leaders in IVF

Israel is the world capital of in vitro fertilisation, with 1,657 in vitro fertilisation procedures being performed, per million people per year. The second highest rate of IVF procedures is in Iceland, with 899 procedures being performed respectively. The United States falls far behind the aforementioned, as well as other European countries, with only 126 procedures being performed per million people per year. Another noteworthy fact is that Israel provides free, unlimited in vitro procedures for its citizens for up to 2 children per woman, under 45 years of age. In other countries the coverage of such procedures is limited if it exists at all. The Israeli Health Ministry says it spends roughly $3,450 per procedure. In the United States an average cycle, from egg retrieval to embryo implantation, costs $12,400. Insurance companies that do cover treatment, even partially, usually cap the amount of cycles they pay for.

LAWS OF THERMODYNAMICS

2012-03-07T08:47:00.005-08:00

LAWS OF THERMODYNAMICS

The four laws of thermodynamics define fundamental physical quantities (temperature, energy, and entropy) that characterize thermodynamic systems. The laws describe how these quantities behave under various circumstances, and forbid certain phenomena (such as perpetual motion).

The four laws of thermodynamics are:

Zeroth law of thermodynamics: If two systems are in thermal equilibrium with a third system, they must be in thermal equilibrium with each other. This law helps define the notion of temperature.

First law of thermodynamics: Heat and work are forms of energy transfer. While energy is invariably conserved, the internal energy of a closed system changes as heat and work are transferred in or out of it. Equivalently, perpetual motion machines of the first kind are impossible.

Second law of thermodynamics: The entropy of any closed system not in thermal equilibrium almost always increases. Closed systems spontaneously evolve towards thermal equilibrium -- the state of maximum entropy of the system -- in a process known as "thermalization". Equivalently, perpetual motion machines of the second kind are impossible.

Third law of thermodynamics: The entropy of a system approaches a constant value as the temperature approaches zero. The entropy of a system at absolute zero is typically zero, and in all cases is determined only by the number of different ground states it has.

Classical thermodynamics describes the exchange of work and heat between systems. It has a special interest in systems that are individually in states of thermodynamic equilibrium. Thermodynamic equilibrium is a condition of systems which are adequately described by only macroscopic variables. Every physical system, however, when microscopically examined, shows apparently random microscopic statistical fluctuations in its thermodynamic variables of state (entropy, temperature, pressure, etc.). These microscopic fluctuations are negligible for systems which are nearly in thermodynamic equilibrium and which are only macroscopically examined. They become important, however, for systems which are nearly in thermodynamic equilibrium when they are microscopically examined, and, exceptionally, for macroscopically examined systems that are in critical states, and for macroscopically examined systems that are far from thermodynamic equilibrium.

There have been suggestions of additional laws, but none of them achieve the generality of the four accepted laws, and they are not mentioned in standard textbooks.

The laws of thermodynamics are important fundamental laws in physics and they are applicable in other natural sciences.

Zeroth law

The zeroth law of thermodynamics may be stated as follows:

If system A and system B are individually in thermal equilibrium with system C, then system A is in thermal equilibrium with system B

The zeroth law implies that thermal equilibrium, viewed as a binary relation, is a Euclidean relation. If we assume that the binary relationship is also reflexive, then it follows that thermal equilibrium is an equivalence relation. Equivalence relations are also transitive and symmetric. The symmetric relationship allows one to speak of two systems being "in thermal equilibrium with each other", which gives rise to a simpler statement of the zeroth law:

If two systems are in thermal equilibrium with a third, they are in thermal equilibrium with each other

However, this statement requires the implicit assumption of both symmetry and reflexivity, rather than reflexivity alone.

The law is also a statement about measurability. To this effect the law allows the establishment of an empirical parameter, the temperature, as a property of a system such that systems in equilibrium with each other have the same temperature. The notion of transitivity permits a system, for example a gas thermometer, to be used as a device to measure the temperature of another system.

Although the concept of thermodynamic equilibrium is fundamental to thermodynamics, the need to state it explicitly as a law was not widely perceived until Fowler and Planck stated it in the 1930s, long after the first, second, and third law were already widely understood and recognized. Hence it was numbered the zeroth law. The importance of the law as a foundation to the earlier laws is that it allows the definition of temperature in a non-circular way without reference to entropy, its conjugate variable.

First law

The first law of thermodynamics may be expressed by several forms of the fundamental thermodynamic relation for a closed system:

Increase in internal energy of a system = heat supplied to the system - work done by the system. U = Q - W

For a thermodynamic cycle, the net heat supplied to the system equals the net work done by the system.

More specifically, the First Law encompasses the following three principles:

The law of conservation of energy

This states that energy can be neither created nor destroyed. However, energy can change forms, and energy can flow from one place to another. The total energy of an isolated system remains the same.

The flow of heat is a form of energy transfer.

(In other words, when heat is flowing from a hot object to a cold object, energy is also flowing from the hot object to the cold object.)

Performing work is a form of energy transfer.

(For example, when a machine lifts a heavy object upwards, some energy is transferred from the machine to the object. The object acquires its energy in the form of gravitational potential energy in this example.)

Combining these three principles gives the first law of thermodynamics.

Second law

The second law of thermodynamics asserts the existence of a quantity called the entropy of a system and further states that

When two isolated systems in separate but nearby regions of space, each in thermodynamic equilibrium in itself (but not necessarily in equilibrium with each other at first) are at some time allowed to interact, breaking the isolation that separates the two systems, allowing them to exchange matter or energy, they will eventually reach a mutual thermodynamic equilibrium. The sum of the entropies of the initial, isolated systems is less than or equal to the entropy of the final combination of exchanging systems. In the process of reaching a new thermodynamic equilibrium, total entropy has increased, or at least has not decreased.

It follows that the entropy of an isolated macroscopic system never decreases. The second law states that spontaneous natural processes increase entropy overall, or in another formulation that heat can spontaneously be conducted or radiated only from a higher-temperature region to a lower-temperature region, but not the other way around.

The second law refers to a wide variety of processes, reversible and irreversible. Its main import is to tell about irreversibility.

The prime example of irreversibility is in the transfer of heat by conduction or radiation. It was known long before the discovery of the notion of entropy that when two bodies of different temperatures are connected with each other by purely thermal connection, conductive or radiative, then heat always flows from the hotter body to the colder one. This fact is part of the basic idea of heat, and is related also to the so-called zeroth law, though the textbooks' statements of the zeroth law are usually reticent about that, because they have been influenced by Carathéodory's basing his axiomatics on the law of conservation of energy and trying to make heat seem a theoretically derivative concept instead of an axiomatically accepted one. Šilahvý (1997) notes that Carathéodory's approach does not work for the description of irreversible processes that involve both heat conduction and conversion of kinetic energy into internal energy by viscosity (which is another prime example of irreversibility), because "the mechanical power and the rate of heating are not expressible as differential forms in the 'external parameters'".

The second law tells also about kinds of irreversibility other than heat transfer, and the notion of entropy is needed to provide that wider scope of the law.

According to the second law of thermodynamics, in a reversible heat transfer, an element of heat transferred, δQ, is the product of the temperature (T), both of the system and of the source or destination of the heat, with the increment (dS) of the system's conjugate variable, its entropy (S)

The second law defines entropy, which may be viewed not only as a macroscopic variable of classical thermodynamics, but may also be viewed as a measure of deficiency of physical information about the microscopic details of the motion and configuration of the system, given only predictable experimental reproducibility of bulk or macroscopic behavior as specified by macroscopic variables that allow the distinction to be made between heat and work. More exactly, the law asserts that for two given macroscopically specified states of a system, there is a quantity called the difference of entropy between them. The entropy difference tells how much additional microscopic physical information is needed to specify one of the macroscopically specified states, given the macroscopic specification of the other, which is often a conveniently chosen reference state. It is often convenient to presuppose the reference state and not to explicitly state it. A final condition of a natural process always contains microscopically specifiable effects which are not fully and exactly predictable from the macroscopic specification of the initial condition of the process. This is why entropy increases in natural processes. The entropy increase tells how much extra microscopic information is needed to tell the final macroscopically specified state from the initial macroscopically specified state.

Third law

The third law of thermodynamics is sometimes stated as follows:

The entropy of a perfect crystal at absolute zero is exactly equal to zero.

At zero temperature the system must be in a state with the minimum possible energy, and this statement of the third law holds true if the perfect crystal has only one state with zero energy. Entropy is related to the number of possible microstates, and with only one microstate, the entropy is exactly zero.

A more general form of the third law that applies to systems such as glasses that may have more than one minimum energy state:

The entropy of a system approaches a constant value as the temperature approaches zero.

The constant value (not necessarily zero) is called the residual entropy of the system.

An equation that helps explain this law is ΔG°=-RT lnK Where G is Gibbs free energy -R is 8.314 Joules/moles·Kelvin and T is temperature in Kelvin and ln K equals natural log of micro states (possible configurations of atoms) So if absolute zero is obtained then there is only 1 micro state possible and ln of 1=0. Zero times the -RT will make the whole equation 0 and therefore gibbs energy is 0 and entropy is 0.

History

In about 1797, Count Rumford (born Benjamin Thompson) showed that mechanical action can generate indefinitely large amounts of heat, so challenging the caloric theory. The historically first established thermodynamic principle which eventually became the second law of thermodynamics was formulated by Sadi Carnot during 1824. By 1860, as formalized in the works of those such as Rudolf Clausius and William Thomson, two established principles of thermodynamics had evolved, the first principle and the second principle, later restated as thermodynamic laws. By 1873, for example, thermodynamicist Josiah Willard Gibbs, in his memoir Graphical Methods in the Thermodynamics of Fluids, clearly stated the first two absolute laws of thermodynamics. Some textbooks throughout the 20th century have numbered the laws differently. In some fields removed from chemistry, the second law was considered to deal with the efficiency of heat engines only, whereas what was called the third law dealt with entropy increases. Directly defining zero points for entropy calculations was not considered to be a law. Gradually, this separation was combined into the second law and the modern third law was widely adopted.

BLOOD PRESSURE

2011-12-29T05:51:00.001-08:00

Blood pressure

Blood pressure (BP) is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies between a maximum (systolic) and a minimum (diastolic) pressure. The mean BP, due to pumping by the heart and resistance to flow in blood vessels, decreases as the circulating blood moves away from the heart through arteries. Blood pressure drops most rapidly along the small arteries and arterioles, and continues to decrease as the blood moves through the capillaries and back to the heart through veins. Gravity, valves in veins, and pumping from contraction of skeletal muscles are some other influences on BP at various places in the body.

The measurement blood pressure without further specification usually refers to the systemic arterial pressure measured at a person's upper arm. It is measured on the inside of an elbow at the brachial artery, which is the upper arm's major blood vessel that carries blood away from the heart. A person's BP is usually expressed in terms of the systolic pressure over diastolic pressure (mmHg), for example 140/90.

Systemic arterial blood pressure

Classification

Classification of blood pressure for adults
Category	systolic, mmHg	diastolic, mmHg
Hypotension	< 90	< 60
Desirable	90–119	60–79
Prehypertension	120–139	or 80–89
Stage 1 Hypertension	140–159	or 90–99
Stage 2 Hypertension	160–179	or 100–109
Hypertensive Crisis	≥ 180	or ≥ 120

The following classifications of blood pressure are from the American Heart Association, and apply to adults 18 years and older. It assumes the values are a result of averaging seated BP readings measured at 2 or more office visits. In the UK, a reading above 140/90 mmHg is considered hypertension.

Normal

While average values for arterial pressure could be computed for any given population, there is often a large variation from person to person; arterial pressure also varies in individuals from moment to moment. Additionally, the average of any given population may have a questionable correlation with its general health; thus the relevance of such average values is equally questionable. However, in a study of 100 human subjects with no known history of hypertension, an average blood pressure of 112/64 mmHg was found, which are currently classified as desirable or "normal" values.

Various factors, such as age and gender influence average values, influence a person's average BP and variations. In children, the normal ranges are lower than for adults and depend on height. As adults age, systolic pressure tends to rise and diastolic tends to fall. In the elderly, BP tends to be above the normal adult range, largely because of reduced flexibility of the arteries. Also, an individual's BP varies with exercise, emotional reactions, sleep, digestion and time of day.

Differences between left and right arm BP measurements tend to be random and average to nearly zero if enough measurements are taken. However, in a small percentage of cases there is a consistent difference greater than 10 mmHg which may need further investigation, e.g. for obstructive arterial disease.

The risk of cardiovascular disease increases progressively above 115/75 mmHg. In the past, hypertension was only diagnosed if secondary signs of high arterial pressure were present, along with a prolonged high systolic pressure reading over several visits. Regarding hypotension, in practice blood pressure is considered too low only if noticeable symptoms are present.

Clinical trials demonstrate that people who maintain arterial pressures at the low end of these pressure ranges have much better long term cardiovascular health. The principal medical debate concerns the aggressiveness and relative value of methods used to lower pressures into this range for those who do not maintain such pressure on their own. Elevations, more commonly seen in older people, though often considered normal, are associated with increased morbidity and mortality.

Average blood pressure in (mmHg):

1 year	6–9 years	adults
95/65	100/65	110/65 – 140/90

Physiology

There are many physical factors that influence arterial pressure. Each of these may in turn be influenced by physiological factors, such as diet, exercise, disease, drugs or alcohol, stress, obesity, and so-forth.

Some physical factors are:

Rate of pumping. In the circulatory system, this rate is called heart rate, the rate at which blood (the fluid) is pumped by the heart. The volume of blood flow from the heart is called the cardiac output which is the heart rate (the rate of contraction) multiplied by the stroke volume (the amount of blood pumped out from the heart with each contraction). The higher the heart rate, the higher the mean arterial pressure, assuming no reduction in stroke volume or central venous return.
Volume of fluid or blood volume, the amount of blood that is present in the body. The more blood present in the body, the higher the rate of blood return to the heart and the resulting cardiac output. There is some relationship between dietary salt intake and increased blood volume, potentially resulting in higher arterial pressure, though this varies with the individual and is highly dependent on autonomic nervous system response and the renin-angiotensin system.
Resistance. In the circulatory system, this is the resistance of the blood vessels. The higher the resistance, the higher the arterial pressure upstream from the resistance to blood flow. Resistance is related to vessel radius (the larger the radius, the lower the resistance), vessel length (the longer the vessel, the higher the resistance), blood viscosity, as well as the smoothness of the blood vessel walls. Smoothness is reduced by the build up of fatty deposits on the arterial walls. Substances called vasoconstrictors can reduce the size of blood vessels, thereby increasing BP. Vasodilators (such as nitroglycerin) increase the size of blood vessels, thereby decreasing arterial pressure. Resistance, and its relation to volumetric flow rate (Q) and pressure difference between the two ends of a vessel are described by Poiseuille's Law.
Viscosity, or thickness of the fluid. If the blood gets thicker, the result is an increase in arterial pressure. Certain medical conditions can change the viscosity of the blood. For instance, anemia (low red blood cell concentration), reduces viscosity, whereas increased red blood cell concentration increases viscosity. It had been thought that aspirin and related "blood thinner" drugs decreased the viscosity of blood, but instead studies found that they act by reducing the tendency of the blood to clot.

In practice, each individual's autonomic nervous system responds to and regulates all these interacting factors so that, although the above issues are important, the actual arterial pressure response of a given individual varies widely because of both split-second and slow-moving responses of the nervous system and end organs. These responses are very effective in changing the variables and resulting BP from moment to moment.

Moreover, blood pressure is the result of cardiac output increased by peripheral resistance: blood pressure = cardiac output X peripheral resistance. As a result, an abnormal change in blood pressure is often an indication of a problem affecting the heart's output, the blood vessels' resistance, or both. Thus, knowing the patient's blood pressure is critical to assess any pathology related to output and resistance.

Mean arterial pressure

The mean arterial pressure (MAP) is the average over a cardiac cycle and is determined by the cardiac output (CO), systemic vascular resistance (SVR), and central venous pressure (CVP),

MAP=(CO.SVR)+CVP

MAP can be approximately determined from measurements of the systolic pressure Psys and the diastolic pressure Pdias while there is a normal resting heart rate,

Pulse pressure

The up and down fluctuation of the arterial pressure results from the pulsatile nature of the cardiac output, i.e. the heartbeat. The pulse pressure is determined by the interaction of the stroke volume of the heart, compliance (ability to expand) of the aorta, and the resistance to flow in the arterial tree. By expanding under pressure, the aorta absorbs some of the force of the blood surge from the heart during a heartbeat. In this way, the pulse pressure is reduced from what it would be if the aorta wasn't compliant. The loss of arterial compliance that occurs with aging explains the elevated pulse pressures found in elderly patients.

The pulse pressure can be simply calculated from the difference of the measured systolic and diastolic pressures,

Arm–leg gradient

The arm–leg (blood pressure) gradient is the difference between the blood pressure measured in the arms and that measured in the legs. It is normally less than 10 mmHg, but may be increased in e.g. coarctation of the aorta.

Vascular resistance

The larger arteries, including all large enough to see without magnification, are conduits with low vascular resistance (assuming no advanced atherosclerotic changes) with high flow rates that generate only small drops in pressure. The smaller arteries and arterioles have higher resistance, and confer the main drop in blood pressure along the circulatory system.

Vascular pressure wave

Modern physiology developed the concept of the vascular pressure wave (VPW). This wave is created by the heart during the systole and originates in the ascending aorta. Much faster than the stream of blood itself, it is then transported through the vessel walls to the peripheral arteries. There the pressure wave can be palpated as the peripheral pulse. As the wave is reflected at the peripheral veins, it runs back in a centripetal fashion. Where the crests of the reflected and the original wave meet, the pressure inside the vessel is higher than the true pressure in the aorta. This concept explains why the arterial pressure inside the peripheral arteries of the legs and arms is higher than the arterial pressure in the aorta, and in turn for the higher pressures seen at the ankle compared to the arm with normal ankle brachial pressure index values.

Regulation

The endogenous regulation of arterial pressure is not completely understood, but the following mechanisms of regulating arterial pressure have been well-characterized:

Baroreceptor reflex: Baroreceptors in the high pressure receptor zones (mainly in the aortic arch and carotid sinus) detect changes in arterial pressure. These baroreceptors send signals ultimately to the medulla of the brain stem, specifically to the Rostral ventrolateral medulla (RVLM). The medulla, by way of the autonomic nervous system, adjusts the mean arterial pressure by altering both the force and speed of the heart's contractions, as well as the total peripheral resistance. The most important arterial baroreceptors are located in the left and right carotid sinuses and in the aortic arch.
Renin-angiotensin system (RAS): This system is generally known for its long-term adjustment of arterial pressure. This system allows the kidney to compensate for loss in blood volume or drops in arterial pressure by activating an endogenous vasoconstrictor known as angiotensin II.
Aldosterone release: This steroid hormone is released from the adrenal cortex in response to angiotensin II or high serum potassium levels. Aldosterone stimulates sodium retention and potassium excretion by the kidneys. Since sodium is the main ion that determines the amount of fluid in the blood vessels by osmosis, aldosterone will increase fluid retention, and indirectly, arterial pressure.
Baroreceptors in low pressure receptor zones (mainly in the venae cavae and the pulmonary veins, and in the atria) result in feedback by regulating the secretion of antidiuretic hormone (ADH/Vasopressin), renin and aldosterone. The resultant increase in blood volume results an increased cardiac output by the Frank–Starling law of the heart, in turn increasing arterial blood pressure.

These different mechanisms are not necessarily independent of each other, as indicated by the link between the RAS and aldosterone release. Currently, the RAS is targeted pharmacologically by ACE inhibitors and angiotensin II receptor antagonists. The aldosterone system is directly targeted by spironolactone, an aldosterone antagonist. The fluid retention may be targeted by diuretics; the antihypertensive effect of diuretics is due to its effect on blood volume. Generally, the baroreceptor reflex is not targeted in hypertension because if blocked, individuals may suffer from orthostatic hypotension and fainting.

Measurement

A medical student checking blood pressure using a sphygmomanometer and stethoscope.

Arterial pressure is most commonly measured via a sphygmomanometer, which historically used the height of a column of mercury to reflect the circulating pressure. BP values are generally reported in millimetres of mercury (mmHg), though aneroid and electronic devices do not use mercury.

For each heartbeat, BP varies between systolic and diastolic pressures. Systolic pressure is peak pressure in the arteries, which occurs near the end of the cardiac cycle when the ventricles are contracting. Diastolic pressure is minimum pressure in the arteries, which occurs near the beginning of the cardiac cycle when the ventricles are filled with blood. An example of normal measured values for a resting, healthy adult human is 120 mmHg systolic and 80 mmHg diastolic (written as 120/80 mmHg, and spoken [in the US and UK] as "one-twenty over eighty").

Systolic and diastolic arterial BPs are not static but undergo natural variations from one heartbeat to another and throughout the day (in a circadian rhythm). They also change in response to stress, nutritional factors, drugs, disease, exercise, and momentarily from standing up. Sometimes the variations are large. Hypertension refers to arterial pressure being abnormally high, as opposed to hypotension, when it is abnormally low. Along with body temperature, respiratory rate, and pulse rate, BP is one of the four main vital signs routinely monitored by medical professionals and healthcare providers.

Measuring pressure invasively, by penetrating the arterial wall to take the measurement, is much less common and usually restricted to a hospital setting.

Noninvasive

The noninvasive auscultatory and oscillometric measurements are simpler and quicker than invasive measurements, require less expertise, have virtually no complications, are less unpleasant and less painful for the patient. However, noninvasive methods may yield somewhat lower accuracy and small systematic differences in numerical results. Noninvasive measurement methods are more commonly used for routine examinations and monitoring.

Palpation

A minimum systolic value can be roughly estimated by palpation, most often used in emergency situations, but should be used with caution. It has been estimated that, using 50% percentiles, carotid, femoral and radial pulses are present in patients with a systolic blood pressure > 70 mmHg, carotid and femoral pulses alone in patients with systolic blood pressure of > 50 mmHg, and only a carotid pulse in patients with a systolic blood pressure of > 40 mmHg.

A more accurate value of systolic BP can be obtained with a sphygmomanometer and palpating the radial pulse. The diastolic blood pressure cannot be estimated by this method. The American Heart Association recommends that palpation be used to get an estimate before using the auscultatory method.

Auscultatory

Auscultatory method aneroid sphygmomanometer with stethoscope

Mercury manometer

The auscultatory method (from the Latin word for "listening") uses a stethoscope and a sphygmomanometer. This comprises an inflatable (Riva-Rocci) cuff placed around the upper arm at roughly the same vertical height as the heart, attached to a mercury or aneroid manometer. The mercury manometer, considered the gold standard, measures the height of a column of mercury, giving an absolute result without need for calibration and, consequently, not subject to the errors and drift of calibration which affect other methods. The use of mercury manometers is often required in clinical trials and for the clinical measurement of hypertension in high-risk patients, such as pregnant women.

A cuff of appropriate size is fitted smoothly and snugly, then inflated manually by repeatedly squeezing a rubber bulb until the artery is completely occluded. Listening with the stethoscope to the brachial artery at the elbow, the examiner slowly releases the pressure in the cuff. When blood just starts to flow in the artery, the turbulent flow creates a "whooshing" or pounding (first Korotkoff sound). The pressure at which this sound is first heard is the systolic BP. The cuff pressure is further released until no sound can be heard (fifth Korotkoff sound), at the diastolic arterial pressure.

The auscultatory method is the predominant method of clinical measurement.

Oscillometric

The oscillometric method was first demonstrated in 1876 and involves the observation of oscillations in the sphygmomanometer cuff pressure which are caused by the oscillations of blood flow, i.e., the pulse. The electronic version of this method is sometimes used in long-term measurements and general practice. It uses a sphygmomanometer cuff, like the auscultatory method, but with an electronic pressure sensor (transducer) to observe cuff pressure oscillations, electronics to automatically interpret them, and automatic inflation and deflation of the cuff. The pressure sensor should be calibrated periodically to maintain accuracy.

Oscillometric measurement requires less skill than the auscultatory technique and may be suitable for use by untrained staff and for automated patient home monitoring.

The cuff is inflated to a pressure initially in excess of the systolic arterial pressure and then reduced to below diastolic pressure over a period of about 30 seconds. When blood flow is nil (cuff pressure exceeding systolic pressure) or unimpeded (cuff pressure below diastolic pressure), cuff pressure will be essentially constant. It is essential that the cuff size is correct: undersized cuffs may yield too high a pressure; oversized cuffs yield too low a pressure. When blood flow is present, but restricted, the cuff pressure, which is monitored by the pressure sensor, will vary periodically in synchrony with the cyclic expansion and contraction of the brachial artery, i.e., it will oscillate. The values of systolic and diastolic pressure are computed, not actually measured from the raw data, using an algorithm; the computed results are displayed.

Oscillometric monitors may produce inaccurate readings in patients with heart and circulation problems, which include arterial sclerosis, arrhythmia, preeclampsia, pulsus alternans, and pulsus paradoxus.

In practice the different methods do not give identical results; an algorithm and experimentally obtained coefficients are used to adjust the oscillometric results to give readings which match the auscultatory results as well as possible. Some equipment uses computer-aided analysis of the instantaneous arterial pressure waveform to determine the systolic, mean, and diastolic points. Since many oscillometric devices have not been validated, caution must be given as most are not suitable in clinical and acute care settings.

The term NIBP, for non-invasive blood pressure, is often used to describe oscillometric monitoring equipment.

White-coat hypertension

For some patients, BP measurements taken in a doctor's office may not correctly characterize their typical BP. In up to 25% of patients, the office measurement is higher than their typical BP. This type of error is called white-coat hypertension (WCH) and can result from anxiety related to an examination by a health care professional. The misdiagnosis of hypertension for these patients can result in needless and possibly harmful medication. WCH can be reduced (but not eliminated) with automated BP measurements over 15 to 20 minutes in a quiet part of the office or clinic.

Debate continues regarding the significance of this effect. Some reactive patients will react to many other stimuli throughout their daily lives and require treatment. In some cases a lower BP reading occurs at the doctor's office.

Home monitoring

Ambulatory blood pressure devices that take readings every half hour throughout the day and night have been used for identifying and mitigating measurement problems like white-coat hypertension. Except for sleep, home monitoring could be used for these purposes instead of ambulatory blood pressure monitoring. Home monitoring may be used to improve hypertension management and to monitor the effects of lifestyle changes and medication related to BP. Compared to ambulatory blood pressure measurements, home monitoring has been found to be an effective and lower cost alternative, but ambulatory monitoring is more accurate than both clinic and home monitoring in diagnosing hypertension. Ambulatory monitoring is recommended for most patients before the start of antihypertensive drugs.

Aside from the white-coat effect, BP readings outside of a clinical setting are usually slightly lower in the majority of people. The studies that looked into the risks from hypertension and the benefits of lowering BP in affected patients were based on readings in a clinical environment.

When measuring BP, an accurate reading requires that one not drink coffee, smoke cigarettes, or engage in strenuous exercise for 30 minutes before taking the reading. A full bladder may have a small effect on BP readings; if the urge to urinate exists, one should do so before the reading. For 5 minutes before the reading, one should sit upright in a chair with one's feet flat on the floor and with limbs uncrossed. The BP cuff should always be against bare skin, as readings taken over a shirt sleeve are less accurate. During the reading, the arm that is used should be relaxed and kept at heart level, for example by resting it on a table.

Since BP varies throughout the day, measurements intended to monitor changes over longer time frames should be taken at the same time of day to ensure that the readings are comparable. Suitable times are:

immediately after awakening (before washing/dressing and taking breakfast/drink), while the body is still resting,
immediately after finishing work.

Automatic self-contained BP monitors are available at reasonable prices, some of which are capable of Korotkoff's measurement in addition to oscillometric methods, enabling irregular heartbeat patients to accurately measure their blood pressure at home.

Invasive

Arterial blood pressure (BP) is most accurately measured invasively through an arterial line. Invasive arterial pressure measurement with intravascular cannulae involves direct measurement of arterial pressure by placing a cannula needle in an artery (usually radial, femoral, dorsalis pedis or brachial).

The cannula must be connected to a sterile, fluid-filled system, which is connected to an electronic pressure transducer. The advantage of this system is that pressure is constantly monitored beat-by-beat, and a waveform (a graph of pressure against time) can be displayed. This invasive technique is regularly employed in human and veterinary intensive care medicine, anesthesiology, and for research purposes.

Cannulation for invasive vascular pressure monitoring is infrequently associated with complications such as thrombosis, infection, and bleeding. Patients with invasive arterial monitoring require very close supervision, as there is a danger of severe bleeding if the line becomes disconnected. It is generally reserved for patients where rapid variations in arterial pressure are anticipated.

Invasive vascular pressure monitors are pressure monitoring systems designed to acquire pressure information for display and processing. There are a variety of invasive vascular pressure monitors for trauma, critical care, and operating room applications. These include single pressure, dual pressure, and multi-parameter (i.e. pressure / temperature). The monitors can be used for measurement and follow-up of arterial, central venous, pulmonary arterial, left atrial, right atrial, femoral arterial, umbilical venous, umbilical arterial, and intracranial pressures.

Fetal blood pressure

Further information: Fetal circulation#Blood pressure

In pregnancy, it is the fetal heart and not the mother's heart that builds up the fetal BP to drive its blood through the fetal circulation.

The BP in the fetal aorta is approximately 30 mmHg at 20 weeks of gestation, and increases to approximately 45 mmHg at 40 weeks of gestation.
The average BP for full-term infants:
Systolic 65–95 mm Hg
Diastolic 30–60 mm Hg

Blood pressure is the measurement of force that is applied to the walls of the blood vessels as the heart pumps blood throughout the body. The human circulatory system is 60,000 miles long, and the magnitude of blood pressure is not uniform in all the blood vessels in the human body. The blood pressure is determined by the diameter, flexibility and the amount of blood being pumped through the blood vessel. Blood pressure is also affected by other factors including exercise, stress level, diet and sleep.

The average normal blood pressure in the brachial artery, which is the next direct artery from the aorta after the subclavian artery, is 120mmHg/80mmHg. Blood pressure readings are measured in millimeters of mercury (mmHg) using sphygmomanometer. Two pressures are measured and recorded namely as systolic and diastolic pressures. Systolic pressure reading is the first reading, which represents the maximum exerted pressure on the vessels when the heart contracts, while the diastolic pressure, the second reading, represents the minimum pressure in the vessels when the heart relaxes. Other major arteries have similar levels of blood pressure recordings indicating very low disparities among major arteries. The innominate artery, the average reading is 110/70mmHg, the right subclavian artery averages 120/80 and the abdominal aorta is 110/70mmHg. The relatively uniform pressure in the arteries indicate that these blood vessels act as a pressure reservoir for fluids that are transported within them.

Pressure drops gradually as blood flows from the major arteries, through the arterioles, the capillaries until blood is pushed up back into the heart via the venules, the veins through the vena cava with the help of the muscles. At any given pressure drop, the flow rate is determined by the resistance to the blood flow. In the arteries, with the absence of diseases, there is very little or no resistance to blood. The vessel diameter is the most principal determinant to control resistance. Compared to other smaller vessels in the body, the artery has a much bigger diameter (4mm), therefore the resistance is low.

In addition, flow rate (Q) is also the product of the cross-sectional area of the vessel and the average velocity (Q=AV). Flow rate is directly proportional to the pressure drop in a tube or in this case a vessel. ∆P α Q. The relationship is further described by Poisseulle’s equation ∆P=8µlQ/πr^4. As evident in the Poisseulle’s equation, although flow rate is proportional to the pressure drop, there are other factors of blood vessels that contribute towards the difference in pressure drop in bifurcations of blood vessels. These include viscosity, length of the vessel, and radius of the vessel.

Factors that determine the flow’s resistance as described by Poiseuille’s relationship:

· ∆P: Pressure drop/gradient

· µ: Viscosity

· l: length of tube. In the case of vessels with infinitely long lengths, l is replaced with diameter of the vessel.

· Q: flow rate of the blood in the vessel

· r: radius of the vessel

Assuming steady, laminar flow in the vessel, the blood vessels behavior is similar to that of a pipe. For instance if p1 and p2 are pressures are at the ends of the tube, the pressure drop/gradient is:

In the arterioles blood pressure is lower than in the major arteries. This is due to bifurcations, which cause a drop in pressure. The more bifurcations, the higher the total cross-sectional area, therefore the pressure across the surface drops. This is why the arterioles have the highest pressure-drop. The pressure drop of the arterioles is the product of flow rate and resistance: ∆P=Q xresistance. The high resistance observed in the arterioles, which factor largely in the ∆P is a result of a smaller radius of about 30 µm. The smaller the radius of a tube, the larger the resistance to fluid flow.

Immediately following the arterioles are the capillaries. Following the logic obvserved in the arterioles, we expect the blood pressure to be lower in the capillaries compared to the arterioles. Since pressure is a function of force per unit area, (P=F/A), the larger the surface area, the lesser the pressure when an external force acts on it. Though the radii of the capillaries are very small, the network of capillaries have the largest surface area in the vascular network. They are known to have the largest surface area (485mm) in the human vascular network. The larger the total cross-sectional area, the lower the mean velocity as well as the pressure.

Reynold’s number also affects the blood flow in capillaries. Due to its smaller radius and lowest velocity compared to other vessels, the Reynold’s number at the capillaries is very low, resulting in laminar instead of turbulent flow.

The Reynold’s number (denoted NR or Re) is a relationship that helps determine the behavior of a fluid in a tube, in this case blood in the vessel. The equation for this dimensionless relationship is written as:

· ρ: density of the blood

· v: mean velocity of the blood

· L: characteristic dimension of the vessel, in this case diameter

· μ: viscosity of blood

The Reynold’s number is directly proportional to the velocity and diameter of the tube. Note that NR is directly proportional to the mean velocity as well as the diameter. A Reynold’s number of less than 2300 is laminar fluid flow, which is characterized by constant flow motion, where as a value of over 4000, is represented as turbulent flow. Turbulent flow is characterized as chaotic and irregular flow.

Disorders

Disregulation disorders of blood pressure control include high blood pressure, blood pressure that is too low, and blood pressure that shows excessive or maladaptive fluctuation.

High

Overview of main complications of persistent high blood pressure.

Arterial hypertension can be an indicator of other problems and may have long-term adverse effects. Sometimes it can be an acute problem, for example hypertensive emergency.

All levels of arterial pressure put mechanical stress on the arterial walls. Higher pressures increase heart workload and progression of unhealthy tissue growth (atheroma) that develops within the walls of arteries. The higher the pressure, the more stress that is present and the more atheroma tend to progress and the heart muscle tends to thicken, enlarge and become weaker over time.

Persistent hypertension is one of the risk factors for strokes, heart attacks, heart failure and arterial aneurysms, and is the leading cause of chronic renal failure. Even moderate elevation of arterial pressure leads to shortened life expectancy. At severely high pressures, mean arterial pressures 50% or more above average, a person can expect to live no more than a few years unless appropriately treated.

In the past, most attention was paid to diastolic pressure; but nowadays it is recognised that both high systolic pressure and high pulse pressure (the numerical difference between systolic and diastolic pressures) are also risk factors. In some cases, it appears that a decrease in excessive diastolic pressure can actually increase risk, due probably to the increased difference between systolic and diastolic pressures (see the article on pulse pressure). If systolic blood pressure is elevated (>140) with a normal diastolic blood pressure (<90), it is called "isolated systolic hypertension" and may present a health concern.

For those with heart valve regurgitation, a change in its severity may be associated with a change in diastolic pressure. In a study of people with heart valve regurgitation that compared measurements 2 weeks apart for each person, there was an increased severity of aortic and mitral regurgitation when diastolic blood pressure increased, whereas when diastolic blood pressure decreased, there was a decreased severity.

Low

Blood pressure that is too low is known as hypotension. The similarity in pronunciation with hypertension can cause confusion. Hypotension is a medical concern only if it causes signs or symptoms, such as dizziness, fainting, or in extreme cases, shock.

When arterial pressure and blood flow decrease beyond a certain point, the perfusion of the brain becomes critically decreased (i.e., the blood supply is not sufficient), causing lightheadedness, dizziness, weakness or fainting.

Sometimes the arterial pressure drops significantly when a patient stands up from sitting. This is known as orthostatic hypotension (postural hypotension); gravity reduces the rate of blood return from the body veins below the heart back to the heart, thus reducing stroke volume and cardiac output.

When people are healthy, the veins below their heart quickly constrict and the heart rate increases to minimize and compensate for the gravity effect. This is carried out involuntarily by the autonomic nervous system. The system usually requires a few seconds to fully adjust and if the compensations are too slow or inadequate, the individual will suffer reduced blood flow to the brain, dizziness and potential blackout. Increases in G-loading, such as routinely experienced by aerobatic or combat pilots 'pulling Gs', greatly increases this effect. Repositioning the body perpendicular to gravity largely eliminates the problem.

Other causes of low arterial pressure include:

Sepsis
Hemorrhage - blood loss
Toxins including toxic doses of BP medicine
Hormonal abnormalities, such as Addison's disease
Eating disorders, particularly anorexia nervosa and bulimia

Shock is a complex condition which leads to critically decreased perfusion. The usual mechanisms are loss of blood volume, pooling of blood within the veins reducing adequate return to the heart and/or low effective heart pumping. Low arterial pressure, especially low pulse pressure, is a sign of shock and contributes to and reflects decreased perfusion.

If there is a significant difference in the pressure from one arm to the other, that may indicate a narrowing (for example, due to aortic coarctation, aortic dissection, thrombosis or embolism) of an artery .

Fluctuating blood pressure

Normal fluctuation in blood pressure is adaptive and necessary. Fluctuations in pressure that are significantly greater than the norm are associated with greater white matter hyperintensity, a finding consistent with reduced local cerebral blood flow and a heightened risk of cerebrovascular disease. Within both high- and low-blood pressure groups, a greater degree of fluctuation was found to correlate with an increase in cerebrovascular disease compared to those with less variability, suggesting the consideration of the clinical management of blood pressure fluctuations, even among normotensive older adults. Older individuals and those who had received blood pressure medications were more likely to exhibit larger fluctuations in pressure.

Blood pressure at other sites

Site		Normal pressure range (in mmHg)
Central venous pressure		3–8
Right ventricular pressure	systolic	15–30
Right ventricular pressure	diastolic	3–8
Pulmonary artery pressure	systolic	15–30
Pulmonary artery pressure	diastolic	4–12
Pulmonary vein/ Pulmonary capillary wedge pressure		2–15
Left ventricular pressure	systolic	100–140
Left ventricular pressure	diastolic	3-12

Blood pressure generally refers to the arterial pressure in the systemic circulation. However, measurement of pressures in the venous system and the pulmonary vessels plays an important role in intensive care medicine but requires an invasive central venous catheter.

Systemic venous pressure

Venous pressure is the vascular pressure in a vein or in the atria of the heart. It is much less than arterial pressure, with common values of 5 mmHg in the right atrium and 8 mmHg in the left atrium.

Variants of venous pressure include:

Central venous pressure, which is a good approximation of right atrial pressure, which is a major determinant of right ventricular end diastolic volume. (However, there can be exceptions in some cases.)
The jugular venous pressure (JVP) is the indirectly observed pressure over the venous system. It can be useful in the differentiation of different forms of heart and lung disease.
The portal venous pressure is the blood pressure in the portal vein. It is normally 5–10 mm Hg.

Pulmonary pressure

Normally, the pressure in the pulmonary artery is about 15 mmHg at rest.

Increased BP in the capillaries of the lung cause pulmonary hypertension, with interstitial edema if the pressure increases to above 20 mmHg, and to frank pulmonary edema at pressures above 25 mmHg.

Relation to wall tension

Regardless of site, blood pressure is related to the wall tension of the vessel according to the Young–Laplace equation (assuming that the vessel wall is very small as compared to the diameter of the lumen):

where

P is the blood pressure
t is the wall thickness
r is the inside radius of the cylinder.
is the cylinder stress or "hoop stress".

For the thin-walled assumption to be valid the vessel must have a wall thickness of no more than about one-tenth (often cited as one twentieth) of its radius.

Components of cylinder stress.

The cylinder stress, in turn, is the average force exerted circumferentially (perpendicular both to the axis and to the radius of the object) in the cylinder wall, and can be described as:

where:

F is the force exerted circumferentially on an area of the cylinder wall that has the following two lengths as sides:
t is the radial thickness of the cylinder
l is the axial length of the cylinder

BLOOD PRESSURE

2011-12-24T11:17:00.000-08:00

Blood pressure

Systemic arterial blood pressure

Classification

Classification of blood pressure for adults
Category	systolic, mmHg	diastolic, mmHg
Hypotension	< 90	< 60
Desirable	90–119	60–79
Prehypertension	120–139	or 80–89
Stage 1 Hypertension	140–159	or 90–99
Stage 2 Hypertension	160–179	or 100–109
Hypertensive Crisis	≥ 180	or ≥ 120

Normal

Average blood pressure in (mmHg):

1 year	6–9 years	adults
95/65	100/65	110/65 – 140/90

Physiology

Some physical factors are:

Rate of pumping. In the circulatory system, this rate is called heart rate, the rate at which blood (the fluid) is pumped by the heart. The volume of blood flow from the heart is called the cardiac output which is the heart rate (the rate of contraction) multiplied by the stroke volume (the amount of blood pumped out from the heart with each contraction). The higher the heart rate, the higher the mean arterial pressure, assuming no reduction in stroke volume or central venous return.
Volume of fluid or blood volume, the amount of blood that is present in the body. The more blood present in the body, the higher the rate of blood return to the heart and the resulting cardiac output. There is some relationship between dietary salt intake and increased blood volume, potentially resulting in higher arterial pressure, though this varies with the individual and is highly dependent on autonomic nervous system response and the renin-angiotensin system.
Resistance. In the circulatory system, this is the resistance of the blood vessels. The higher the resistance, the higher the arterial pressure upstream from the resistance to blood flow. Resistance is related to vessel radius (the larger the radius, the lower the resistance), vessel length (the longer the vessel, the higher the resistance), blood viscosity, as well as the smoothness of the blood vessel walls. Smoothness is reduced by the build up of fatty deposits on the arterial walls. Substances called vasoconstrictors can reduce the size of blood vessels, thereby increasing BP. Vasodilators (such as nitroglycerin) increase the size of blood vessels, thereby decreasing arterial pressure. Resistance, and its relation to volumetric flow rate (Q) and pressure difference between the two ends of a vessel are described by Poiseuille's Law.
Viscosity, or thickness of the fluid. If the blood gets thicker, the result is an increase in arterial pressure. Certain medical conditions can change the viscosity of the blood. For instance, anemia (low red blood cell concentration), reduces viscosity, whereas increased red blood cell concentration increases viscosity. It had been thought that aspirin and related "blood thinner" drugs decreased the viscosity of blood, but instead studies found that they act by reducing the tendency of the blood to clot.

Mean arterial pressure

The mean arterial pressure (MAP) is the average over a cardiac cycle and is determined by the cardiac output (CO), systemic vascular resistance (SVR), and central venous pressure (CVP),

MAP=(CO.SVR)+CVP

MAP can be approximately determined from measurements of the systolic pressure Psys and the diastolic pressure Pdias while there is a normal resting heart rate,

Pulse pressure

The pulse pressure can be simply calculated from the difference of the measured systolic and diastolic pressures,

Arm–leg gradient

Vascular resistance

Vascular pressure wave

Regulation

The endogenous regulation of arterial pressure is not completely understood, but the following mechanisms of regulating arterial pressure have been well-characterized:

Baroreceptor reflex: Baroreceptors in the high pressure receptor zones (mainly in the aortic arch and carotid sinus) detect changes in arterial pressure. These baroreceptors send signals ultimately to the medulla of the brain stem, specifically to the Rostral ventrolateral medulla (RVLM). The medulla, by way of the autonomic nervous system, adjusts the mean arterial pressure by altering both the force and speed of the heart's contractions, as well as the total peripheral resistance. The most important arterial baroreceptors are located in the left and right carotid sinuses and in the aortic arch.
Renin-angiotensin system (RAS): This system is generally known for its long-term adjustment of arterial pressure. This system allows the kidney to compensate for loss in blood volume or drops in arterial pressure by activating an endogenous vasoconstrictor known as angiotensin II.
Aldosterone release: This steroid hormone is released from the adrenal cortex in response to angiotensin II or high serum potassium levels. Aldosterone stimulates sodium retention and potassium excretion by the kidneys. Since sodium is the main ion that determines the amount of fluid in the blood vessels by osmosis, aldosterone will increase fluid retention, and indirectly, arterial pressure.
Baroreceptors in low pressure receptor zones (mainly in the venae cavae and the pulmonary veins, and in the atria) result in feedback by regulating the secretion of antidiuretic hormone (ADH/Vasopressin), renin and aldosterone. The resultant increase in blood volume results an increased cardiac output by the Frank–Starling law of the heart, in turn increasing arterial blood pressure.

Measurement

A medical student checking blood pressure using a sphygmomanometer and stethoscope.

Measuring pressure invasively, by penetrating the arterial wall to take the measurement, is much less common and usually restricted to a hospital setting.

Noninvasive

Palpation

Auscultatory

Auscultatory method aneroid sphygmomanometer with stethoscope

Mercury manometer

The auscultatory method is the predominant method of clinical measurement.

Oscillometric

Oscillometric measurement requires less skill than the auscultatory technique and may be suitable for use by untrained staff and for automated patient home monitoring.

The term NIBP, for non-invasive blood pressure, is often used to describe oscillometric monitoring equipment.

White-coat hypertension

Home monitoring

immediately after awakening (before washing/dressing and taking breakfast/drink), while the body is still resting,
immediately after finishing work.

Invasive

Fetal blood pressure

Further information: Fetal circulation#Blood pressure

In pregnancy, it is the fetal heart and not the mother's heart that builds up the fetal BP to drive its blood through the fetal circulation.

Factors that determine the flow’s resistance as described by Poiseuille’s relationship:

· ∆P: Pressure drop/gradient

· µ: Viscosity

· l: length of tube. In the case of vessels with infinitely long lengths, l is replaced with diameter of the vessel.

· Q: flow rate of the blood in the vessel

· r: radius of the vessel

· ρ: density of the blood

· v: mean velocity of the blood

· L: characteristic dimension of the vessel, in this case diameter

· μ: viscosity of blood

Disorders

Disregulation disorders of blood pressure control include high blood pressure, blood pressure that is too low, and blood pressure that shows excessive or maladaptive fluctuation.

High

Overview of main complications of persistent high blood pressure.

Arterial hypertension can be an indicator of other problems and may have long-term adverse effects. Sometimes it can be an acute problem, for example hypertensive emergency.

Low

Other causes of low arterial pressure include:

Sepsis
Hemorrhage - blood loss
Toxins including toxic doses of BP medicine
Hormonal abnormalities, such as Addison's disease
Eating disorders, particularly anorexia nervosa and bulimia

Fluctuating blood pressure

Blood pressure at other sites

Site		Normal pressure range (in mmHg)
Central venous pressure		3–8
Right ventricular pressure	systolic	15–30
Right ventricular pressure	diastolic	3–8
Pulmonary artery pressure	systolic	15–30
Pulmonary artery pressure	diastolic	4–12
Pulmonary vein/ Pulmonary capillary wedge pressure		2–15
Left ventricular pressure	systolic	100–140
Left ventricular pressure	diastolic	3-12

Systemic venous pressure

Variants of venous pressure include:

Central venous pressure, which is a good approximation of right atrial pressure, which is a major determinant of right ventricular end diastolic volume. (However, there can be exceptions in some cases.)
The jugular venous pressure (JVP) is the indirectly observed pressure over the venous system. It can be useful in the differentiation of different forms of heart and lung disease.
The portal venous pressure is the blood pressure in the portal vein. It is normally 5–10 mm Hg.

Pulmonary pressure

Normally, the pressure in the pulmonary artery is about 15 mmHg at rest.

Increased BP in the capillaries of the lung cause pulmonary hypertension, with interstitial edema if the pressure increases to above 20 mmHg, and to frank pulmonary edema at pressures above 25 mmHg.

Relation to wall tension

where

P is the blood pressure
t is the wall thickness
r is the inside radius of the cylinder.
is the cylinder stress or "hoop stress".

For the thin-walled assumption to be valid the vessel must have a wall thickness of no more than about one-tenth (often cited as one twentieth) of its radius.

Components of cylinder stress.

The cylinder stress, in turn, is the average force exerted circumferentially (perpendicular both to the axis and to the radius of the object) in the cylinder wall, and can be described as:

where:

F is the force exerted circumferentially on an area of the cylinder wall that has the following two lengths as sides:
t is the radial thickness of the cylinder
l is the axial length of the cylinder

Environmental Warfare and US Foreign Policy: The Ultimate Weapon of Mass Destruction

2011-10-31T10:55:00.000-07:00

by Scott Gilbert
Environmental warfare may sound new to some, but it has been researched extensively in military circles for years. The first public description of weather modification techniques as a weapon of war was made on 20 March, 1974. At that time the Pentagon revealed a seven-year cloud seeding effort in Vietnam and Cambodia, costing $21.6 million. The objective was to increase rainfall in target areas, thereby causing landslides and making unpaved roads muddy, hindering the movement of supplies. (1) But interest in the exploitation of the environment for military purposes did not end there. Air University, located at Maxwell Air Force Base in Alabama, describes itself as a "center for advanced education" that "plays a vital role in fulfilling the mission of the United States Air Force" and whose "service members must place the nation's defense above self." The Chief of Staff of the US Air Force tasked Air University to "look 30 years into the future to identify the concepts, capabilities and technologies the United States will require to remain the dominant air and space force in the 21st century." The study, completed in 1996, was titled Air Force 2025. One component was of the study was a paper titledWeather as a Force Multiplier: Owning the Weather in 2025. It is a chilling document. It is evident that the authors regard our environment as nothing more than a resource to be exploited for military purposes. They claim that by 2025 US forces can "own the weather" by "capitalizing on emerging technologies and focusing development of those technologies to warfighting applications." The authors describe weather modification as having "tremendous military capabilities" which "can provide battlespace dominance to a degree never before imagined," claiming the project would be "not unlike the splitting of the atom." The paper goes on to discuss how ionospheric research (The ionosphere is a region of the earth’s atmosphere ranging from about 30 – 1200 miles above the surface of the earth.) is necessary to achieve goals in both enhancing US communication capabilities and as a method of disabling enemy communications. "By 2025, it may be possible to modify the ionosphere and near space, creating a variety of potential applications." (2)Dr. Bernard Eastlund, while working as a consultant for Advanced Power Technologies Inc. (APTI) in the 1980s, patented devices that are described as capable of "causing…total disruption of communications over a very large portion of the Earth…missile or aircraft destruction, deflection or confusion…weather modification…" (3) These patents were based on the ideas and fundamental research of Nicola Tesla (many of his ideas were stolen by US corporations). Some of Eastlund's patents were temporarily sealed under a US Secrecy Order. APTI and Eastlund’s patents were quickly purchased by E-Systems, a company that is home to many retired and currently employed CIA agents. In 1993 E-Systems received $1.8 billion in classified contracts. Raytheon, the fourth largest US defense contractor and third largest aerospace company, currently holds the patents. (4) In light of the above, it is significant to know that since the early 1990s the US Air Force has been sponsoring the world’s largest ionospheric modification project called HAARP (High-frequency Active Auroral Research Program). HAARP, located in the remote bush country of Gakona, Alaska, is a small version of the antenna discussed in the Eastlund patents. APTI initially won the contract to build HAARP. Eastlund feels that the current version of HAARP, although the largest ionospheric heater ever built, is not yet powerful enough to bring the ideas in his patents to fruition, "But," he says, "they're getting up there. This is a very powerful device. Especially if they go to the expanded stage." (5) What they have done to date is definitely a necessary first step in the overall objective. Eastlund says, "The military was interested [in his patents] because, in the event of a Russian nuclear attack on the United States, an Alaskan site would be under the path of the incoming warheads."(6) HAARP is currently a part of the ongoing Strategic Defense Initiative (SDI), popularly known as "Star Wars". (7) A 1990 internal document obtained by Popular Science describes applications of the HAARP project as "Creating a "full global shield" that would destroy ballistic missiles by overheating their electronic guiding systems as they fly" and for "manipulating local weather." (8) The word "local" was used because some 150 international treaties prohibit "weather warfare". (5) However, Pravda reported: "the works continued anyway, despite the signed document. It was simply conducted under the disguise of scientific research or the development of double-purpose technology." (9)
HAARP is presented as a harmless scientific project, but The Washington Post reported that a growing number of physicists and others in the scientific community are becoming increasingly skeptical. A "small group of American physicists, some of whom have aired complaints in scientific journals…fear HAARP may not simply be the benign research experiment advocates describe, but possibly phase one of a secret US military program that could be seeking ways to blow other countries’ spacecraft out of the sky or disrupt communications over large portions of the planet." (6) Richard Williams, a physicist and consultant to the David Sarnoff laboratory in Princeton alleges HAARP constitutes "an irresponsible act of global vandalism." He and others fear a secret second stage where HAARP would "beam much more energy into the ionosphere. That could produce a severe disruption of the upper atmosphere at one location that may produce effects that spread rapidly around the Earth for years." (6) In 2002 the website globalresearch.ca reported that the Russian State Duma's International Affairs and Defence Committee expressed concern that "Under the HAARP program the USA is creating new integral geophysical weapons that may influence the near-Earth medium with high-frequency radio waves…the significance of this qualitative leap could be compared to the transition from cold steel to firearms, or from conventional weapons to nuclear weapons." The deputies demanded an international ban on large-scale geophysical experiments of this sort and sent the appeal to President Vladimir Putin, news outlets, scientific groups, the UN and others. The article went on to say that the HAARP program "will create weapons capable of breaking radio communication lines and equipment installed on spaceships and rockets, provoke serious accidents in electricity networks and in oil and gas pipelines and have a negative impact on the mental health of people populating entire regions." (10) Dr. Nicholas Begich, co-author of the book Angels Don’t Play This HAARP, depicts HAARP as "a super-powerful radio wave beaming technology that lifts areas of the ionosphere by focusing a beam on them and then heating them. Electromagnetic waves then bounce back onto earth and penetrate everything - living and dead." This ability allows for better communication with submarines and wide-area Earth-penetrating tomography (similar to radar) that can be used to locate underground missile sites, bunkers and oil reserves. Through his research he has come to the conclusion that HAARP has the potential to jam global communication systems, change weather patterns over large areas, interfere with wildlife migration patterns and negatively affect human health. It is also capable of potentially triggering targeted floods, droughts, hurricanes and earthquakes. (11) Dr. Rosalie Bertell, author of Planet Earth: The Latest Weapon of War and founder of the International Institute of Concern for Public Health, while writing on the background of HAARP says, "It would be rash to assume that HAARP is an isolated experiment which would not be expanded. It is related to fifty years of intensive and increasingly destructive programs to understand and control the upper atmosphere… It would be rash not to associate HAARP with the space laboratory construction which is separately being planned by the United States…The ability of the HAARP/Spacelab/rocket combination to deliver very large amount of energy, comparable to a nuclear bomb, anywhere on earth via laser and particle beams, are frightening…The project is likely to be "sold" to the public as a space shield against incoming weapons, or, for the more gullible, a device for repairing the ozone layer." (12) Michel Chossudovsky, professor of economics at the University of Ottawa and Director of the Center for Research on Globalization, says that "there are very clear statements by the US Air Force to the effect that weather modification technology is available, HAARP is fully operational and could be used in actually military situations. It is evident weather warfare does constitute an instrument of the Air Force, they even identify the scenarios of its use." He said his interest in the topic was sparked by the fact that it is possible to change climate and disrupt electricity over large areas of the Earth, effectively destabilizing portions of the globe and paralysing national economies. This can be done without the enemy even knowing the source of it. The health and economic prosperity of entire regions could potentially be devastated through climatic manipulations without the deployment of a single troop or the firing of any munitions. It is naïve to assume that those who ordered the development of the nuclear bomb would not want total control over this technology. Chossudovsky says HAARP can act as a "weapon of mass destruction" because it can destroy industry, infrastructure, agriculture and cause loss of life. He questions whether HAARP should be used at all since it has "global and environmental implications" and because it affects the electromagnetic field of the Earth. (13) In September 2003 the websiteglobalresearch.ca reported that a scientist who works in ionospheric research expressed concern that the 14 August, 2003 blackout might have been "a secret government test" that served multiple purposes including "fulfilling requirements for sophisticated warfare and security response." The author poses the question: Could a secret HAARP experiment have caused the blackout? This article was based on a number of facts that seemed oddly coincidental given the circumstances. For example, the power went out a few minutes after the closing bell on Wall Street and a few minutes after HAARP was turned on that day. The power grid that was affected was not the vulnerable California grid. The data that would show where the effects of HAARP were directed, by providing a picture of the ionosphere, were not posted on the day of the blackout. He also commented on the possibility that the HAARP heaters were directed at the power grid's bottleneck while the grid was operating near full power. "The sudden presence of electromagnetic energy could easily force an unexpected increase in the power flow which could in-turn cause a critical failure such as the one seen on August 14, 2003…The only requirement to achieve geographic precision is that geomagnetic activity be minimal such as it was on the day of the blackout." There was also a short test conducted shortly before 4pm. The author says such a test would serve the purpose of "showing the researchers exactly where the beam would focus itself given the current conditions, and would be a necessary step before executing such an experiment." The author describes how experiments of this sort would be an "ideal way to test possible military applications of the instrument…of course, this would need to be tested in a controlled environment where the effects could be thoroughly analyzed (such as on our own soil)…this was an excellent homeland security response test." He concludes by saying "Although it may sound like an episode of the X-files, the facts are clear; HAARP is an ionospheric warfare tool, it is capable of focusing it's electromagnetic energy at long distances, it was turned on right at the time the event began, and such a scenario would serve multiple national security interests simultaneously with minimal economic impact." (14) Michel Chossudovsky, by conferring with other well-known scientists, was able to conclude, "this man knows the facts. He can read and analyse scientific data and is well informed on the impact of the HAARP program." Although the article does not amount to proof, Chossudovsky feels that the author’s statements should be taken seriously and investigated. (13, 14) The HAARP program was scheduled for completion in 2002 and full-scale testing had started by early 2003. While there is currently no conclusive proof that HAARP has ever been used for weather manipulation, there have been numerous reports describing very unusual weather and environmental conditions throughout the world in recent years. In January 2003 Yuru Solomatin, secretary of the Ukrainian Committee for Economic Policy, writing in Pravda reported "A lot of specialists and scientists believe that unpredictable natural disasters and several … catastrophes that struck Europe and Asia in the summer of 2002 might have certain global reasons that caused them all." He posits "a possibility of secret geophysical weapon tests. Those tests were either secret or unauthorized… [Many] specialists and scientists believe that a special American program HAARP is one of those developments."(9) Chossudovsky says, "Even though we do not have clear-cut information on particular climatic occurrences, when there are very unusual weather patters that are occurring, which cannot be explained by greenhouse gas emissions, we cannot exclude the possibility of man-made climatic manipulations, based on our understanding of climate." (13) A primary objection to weather modification for military purposes is that its use is indiscriminant and civilians will inevitably be affected. Furthermore, the research necessary to achieve these goals is dangerous. According to Bertell, HAARP can make "long incisions in the protective layer of the Earth’s atmosphere."(7) As with the Manhattan project, scientists working on this massive military project simply are not able to determine for certain whether or not their activities will cause irreparable damage. Nor do they seem to care. In 1971 Science published an article titled Modifying the Ionosphere with Intense Radio Waves in which the authors describe the development of radio wave beaming technology for ionospheric modification that has long been "a desire for researchers." This new technology now allows them to conduct research without the "associated complications" of a laboratory. They now have a "plasma laboratory in the sky." (15) There is a dire need for this technology to be closely monitored by multiple independent scientific bodies (it currently is not) and, if it must be used, needs to be used in such a way as to be beneficial to life on earth. It could be used to increase food supply, repair the ozone layer or reduce damage to civilian populations frequently affected by adverse weather conditions. Sadly, current military agendas appear not to give much weight to these possible beneficial uses of the technology.

GREAT WALL OF CHINA

2011-10-10T11:54:00.000-07:00

Great Wall of China

The Great Wall of China is a series of stone and earthen fortifications in northern China, built originally to protect the northern borders of the Chinese Empire against intrusions by various nomadic groups. Several walls have been built since the 5th century BC that are referred to collectively as the Great Wall, which has been rebuilt and maintained from the 5th century BC through the 16th century. One of the most famous is the wall built between 220–206 BC by the first Emperor of China, Qin Shi Huang. Little of that wall remains; the majority of the existing wall was built during the Ming Dynasty.

The Great Wall stretches from Shanhaiguan in the east, to Lop Lake in the west, along an arc that roughly delineates the southern edge of Inner Mongolia. The most comprehensive archaeological survey, using advanced technologies, has concluded that all the walls measure 8,851.8 km (5,500.3 mi). This is made up of 6,259.6 km (3,889.5 mi) sections of actual wall, 359.7 km (223.5 mi) of trenches and 2,232.5 km (1,387.2 mi) of natural defensive barriers such as hills and rivers.

History

The early walls

Great Wall of the Qin Dynasty

Great Wall of the Han Dynasty

Great Wall of the Ming Dynasty

The Chinese were already familiar with the techniques of wall-building by the time of the Spring and Autumn Period, which began around the 8th century BC. During the Warring States Period from the 5th century BCE to 221 BCE, the states of Qin, Wei, Zhao, Qi, Yan and Zhongshan all constructed extensive fortifications to defend their own borders. Built to withstand the attack of small arms such as swords and spears, these walls were made mostly by stamping earth and gravel between board frames.

Qin Shi Huang conquered all opposing states and unified China in 221 BCE, establishing the Qin Dynasty. Intending to impose centralized rule and prevent the resurgence of feudal lords, he ordered the destruction of the wall sections that divided his empire along the former state borders. To protect the empire against intrusions by the Xiongnu people from the north, he ordered the building of a new wall to connect the remaining fortifications along the empire's new northern frontier. Transporting the large quantity of materials required for construction was difficult, so builders always tried to use local resources. Stones from the mountains were used over mountain ranges, while rammed earth was used for construction in the plains. There are no surviving historical records indicating the exact length and course of the Qin Dynasty walls. Most of the ancient walls have eroded away over the centuries, and very few sections remain today. The human cost of the construction is unknown, but it has been estimated by some authors that hundreds of thousands, if not up to a million, workers died building the Qin wall. Later, the Han, Sui, and Northern dynasties all repaired, rebuilt, or expanded sections of the Great Wall at great cost to defend themselves against northern invaders. The Tang and Song Dynasties did not build any walls in the region. The Liao, Jin, and Yuan dynasties, who ruled Northern China throughout most of the 10-13th centuries, had their original power bases north of the Great Wall proper; accordingly, they would have no need throughout most of their history to build a wall along this line. The Liao carried out limited repair of the Great Wall in a few areas, however the Jin did construct defensive walls in the 12th century, but those were located much to the north of the Great Wall as we know it, within today's Inner and Outer Mongolia.

The Ming era

The Great Wall concept was revived again during the Ming Dynasty in the 14th century, and following the Ming army's defeat by the Oirats in the Battle of Tumu in 1449. The Ming had failed to gain a clear upper hand over the Manchurian and Mongolian tribes after successive battles, and the long-drawn conflict was taking a toll on the empire. The Ming adopted a new strategy to keep the nomadic tribes out by constructing walls along the northern border of China. Acknowledging the Mongol control established in the Ordos Desert, the wall followed the desert's southern edge instead of incorporating the bend of the Huang He.

Unlike the earlier Qin fortifications, the Ming construction was stronger and more elaborate due to the use of bricks and stone instead of rammed earth. As Mongol raids continued periodically over the years, the Ming devoted considerable resources to repair and reinforce the walls. Sections near the Ming capital of Beijing were especially strong.

During the 1440s–1460s, the Ming also built a so-called "Liaodong Wall". Similar in function to the Great Wall (whose extension, in a sense, it was), but more basic in construction, the Liaodong Wall enclosed the agricultural heartland of the Liaodong province, protecting it against potential incursions by Jurched-Mongol Oriyanghan from the northwest and the Jianzhou Jurchens from the north. While stones and tiles were used in some parts of the Liaodong Wall, most of it was in fact simply an earth dike with moats on both sides.

Towards the end of the Ming Dynasty, the Great Wall helped defend the empire against the Manchu invasions that began around 1600. Even after the loss of all of Liaodong, the Ming army under the command of Yuan Chonghuan held off the Manchus at the heavily fortified Shanhaiguan pass, preventing the Manchus from entering the Chinese heartland. The Manchus were finally able to cross the Great Wall in 1644, after Beijing had fallen to Li Zicheng's rebels, and the gates at Shanhaiguan were opened by the commanding Ming general Wu Sangui, who hoped to use the Manchus to expel the rebels from Beijing. The Manchus quickly seized Beijing, and defeated both the rebel-founded Shun Dynasty and the remaining Ming resistance, establishing the Qing Dynasty rule over the entire China.

In 2009, an additional 290 km (180 mi) of previously undetected portions of the wall, built during the Ming Dynasty, were discovered. The newly discovered sections range from the Hushan mountains in the northern Liaoning province, to Jiayuguan in western Gansu province. The sections had been submerged over time by sandstorms which moved across the arid region.

Under Qing rule, China's borders extended beyond the walls and Mongolia was annexed into the empire, so construction and repairs on the Great Wall were discontinued. On the other hand, the so-called Willow Palisade, following a line similar to that of the Ming Liaodong Wall, was constructed by the Qing rulers in Manchuria. Its purpose, however, was not defense but rather migration control.

Early Western reports of the wall

The North African traveler Ibn Battuta, who was in Guangzhou ca. 1346, inquired among the local Muslims about the wall that, according to the Qur'an, Dhul-Qarnayn had built to contain Gog and Magog. Ibn Battuta reported that the wall was "sixty days' travel" from the city of Zeitun (Quanzhou); Hamilton Alexander Rosskeen Gibb noted Ibn Battuta has confused the Great Wall of China with that built by Dhul-Qarnayn. This indicated that Arabs may have heard about China's Great Wall during earlier periods of China's history, and associated it with the Gog and Magog wall of the Qur'an. But, in any event, no one of Ibn Battuta's Guangzhou interlocutors had seen the wall or knew anyone who had seen it, which implies that by the late Yuan the existence of the Great Wall was not in the people's living memory, at least not in the Muslim communities in Guangzhou.

Soon after Europeans reached the Ming China in the early 16th century, accounts of the Great Wall started to circulate in Europe, even though no European was to see it with his own eyes for another century. Possibly the earliest description of the wall, and its significance for the defense of the country against the "Tartars" (i.e. Mongols), may be the one contained in the Third Década of João de Barros' Asia (published 1563). Interestingly, Barros himself did not travel to Asia, but was able to use Chinese books brought to Lisbon by Portuguese traders. One of the earliest records of a Western traveler entering China via a Great Wall pass (Jiayuguan, in this case) may be that of the Portuguese Jesuit brother Bento de Góis, who had reached China's north-western gate from India in 1605.

Notable areas

Photograph of the Great Wall in 1907

An area of the sections of the Great Wall at Jinshanling

The Great Wall

Some of the following sections are in Beijing municipality, which were renovated and which are regularly visited by modern tourists today.

"North Pass" of Juyongguan pass, known as the Badaling. When used by the Chinese to protect their land, this section of the wall has had many guards to defend China’s capital Beijing. Made of stone and bricks from the hills, this portion of the Great Wall is 7.8 meters (26 ft) high and 5 meters (16 ft) wide.
"West Pass" of Jiayuguan (pass). This fort is near the western edges of the Great Wall.
"Pass" of Shanhaiguan. This fort is near the eastern edges of the Great Wall.
One of the most striking sections of the Ming Great Wall is where it climbs extremely steep slopes. It runs 11 kilometers (6.8 mi) long, ranges from 5 to 8 meters (16–26 ft) in height, and 6 meters (20 ft) across the bottom, narrowing up to 5 meters (16 ft) across the top. Wangjinglou is one of Jinshanling's 67 watchtowers, 980 meters (3,220 ft) above sea level.
South East of Jinshanling, is the Mutianyu Great Wall which winds along lofty, cragged mountains from the southeast to the northwest for approximately 2.25 kilometers (about 1.3 miles). It is connected with Juyongguan Pass to the west and Gubeikou to the east.
25 km (16 mi) west of the Liao Tian Ling stands apart of Great Wall which is only 2~3 stories high. According to the records of Lin Tian, the wall was not only extremely short compared to others, but it appears to be silver. Archeologists explain that the wall appears to be silver because the stone they used were from Shan Xi, where many mines are found. The stone contains extremely high levels of metal in it causing it to appear silver. However, due to years of decay of the Great Wall, it is hard to see the silver part of the wall today.

Another notable section lies near the eastern extremity of the wall, where the first pass of the Great Wall was built on the Shanhaiguan (known as the “Number One Pass Under Heaven”). 3 km north of Shanhaiguan is Jiaoshan Great Wall, the site of the first mountain of the Great Wall. 15 km northeast from Shanhaiguan, is the Jiumenkou, which is the only portion of the wall that was built as a bridge.

Characteristics

Before the use of bricks, the Great Wall was mainly built from rammed earth, stones, and wood. During the Ming Dynasty, however, bricks were heavily used in many areas of the wall, as were materials such as tiles, lime, and stone. The size and weight of the bricks made them easier to work with than earth and stone, so construction quickened. Additionally, bricks could bear more weight and endure better than rammed earth. Stone can hold under its own weight better than brick, but is more difficult to use. Consequently, stones cut in rectangular shapes were used for the foundation, inner and outer brims, and gateways of the wall. Battlements line the uppermost portion of the vast majority of the wall, with defensive gaps a little over 30 cm (12 in) tall, and about 23 cm (9.1 in) wide.

Condition

The Great Wall at Mutianyu, near Beijing

While some portions north of Beijing and near tourist centers have been preserved and even extensively renovated, in many locations the Wall is in disrepair. Those parts might serve as a village playground or a source of stones to rebuild houses and roads. Sections of the Wall are also prone to graffiti and vandalism. Parts have been destroyed because the Wall is in the way of construction.

More than 60 km (37 mi) of the wall in Gansu province may disappear in the next 20 years, due to erosion from sandstorms. In places, the height of the wall has been reduced from more than five meters (16.4 ft) to less than two meters. The square lookout towers that characterize the most famous images of the wall have disappeared completely. Many western sections of the wall are constructed from mud, rather than brick and stone, and thus are more susceptible to erosion.

Watchtowers and barracks

Communication between the army units along the length of the Great Wall, including the ability to call reinforcements and warn garrisons of enemy movements, was of high importance. Signal towers were built upon hill tops or other high points along the wall for their visibility.

Visibility from space

Visibility from the moon

One of the earliest known references to this myth appears in a letter written in 1754 by the English antiquary William Stukeley. Stukeley wrote that, "This mighty wall of four score miles in length (Hadrian's Wall) is only exceeded by the Chinese Wall, which makes a considerable figure upon the terrestrial globe, and may be discerned at the moon." The claim was also mentioned by Henry Norman in 1895 where he states "besides its age it enjoys the reputation of being the only work of human hands on the globe visible from the moon." The issue of "canals" on Mars was prominent in the late 19th century and may have led to the belief that long, thin objects were visible from space. The claim that the Great Wall is visible also appears in 1932's Ripley's Believe it or Not strip and in Richard Halliburton's 1938 book Second Book of Marvels.

The claim the Great Wall is visible has been debunked many times, but is still ingrained in popular culture. The wall is a maximum 9.1 m (30 ft) wide, and is about the same color as the soil surrounding it. Based on the optics of resolving power (distance versus the width of the iris: a few millimeters for the human eye, meters for large telescopes) only an object of reasonable contrast to its surroundings which is 70 mi (110 km) or more in diameter (1 arc-minute) would be visible to the unaided eye from the moon, whose average distance from Earth is 384,393 km (238,851 mi). The apparent width of the Great Wall from the moon is the same as that of a human hair viewed from 2 miles (3.2 km) away. To see the wall from the moon would require spatial resolution 17,000 times better than normal (20/20) vision. Unsurprisingly, no lunar astronaut has ever claimed to have seen the Great Wall from the moon.

Visibility from low earth orbit

A more controversial question is whether the Wall is visible from low earth orbit (an altitude of as little as 100 miles (160 km)). NASA claims that it is barely visible, and only under nearly perfect conditions; it is no more conspicuous than many other man-made objects. Other authors have argued that due to limitations of the optics of the eye and the spacing of photoreceptors on the retina, it is impossible to see the wall with the naked eye, even from low orbit, and would require visual acuity of 20/3 (7.7 times better than normal).

Anecdotal reports

Astronaut William Pogue thought he had seen it from Skylab but discovered he was actually looking at the Grand Canal of China near Beijing. He spotted the Great Wall with binoculars, but said that "it wasn't visible to the unaided eye." U.S. Senator Jake Garn claimed to be able to see the Great Wall with the naked eye from a space shuttle orbit in the early 1980s, but his claim has been disputed by several U.S. astronauts. Veteran U.S. astronaut Gene Cernan has stated: "At Earth orbit of 100 miles (160 km) to 200 miles (320 km) high, the Great Wall of China is, indeed, visible to the naked eye." Ed Lu, Expedition 7 Science Officer aboard the International Space Station, adds that, "it's less visible than a lot of other objects. And you have to know where to look."

In 2001, Neil Armstrong stated about the view from Apollo 11: "I do not believe that, at least with my eyes, there would be any man-made object that I could see. I have not yet found somebody who has told me they've seen the Wall of China from Earth orbit. ...I've asked various people, particularly Shuttle guys, that have been many orbits around China in the daytime, and the ones I've talked to didn't see it.

In October 2003, Chinese astronaut Yang Liwei stated that he had not been able to see the Great Wall of China. In response, the European Space Agency (ESA) issued a press release reporting that from an orbit between 160 and 320 km, the Great Wall is visible to the naked eye. In an attempt to further clarify things, the ESA published a picture of a part of the “Great Wall” photographed from Space. However, in a press release a week later (no longer available in the ESA’s website), they acknowledged that the "Great Wall" in the picture was actually a river.

Leroy Chiao, a Chinese-American astronaut, took a photograph from the International Space Station that shows the wall. It was so indistinct that the photographer was not certain he had actually captured it. Based on the photograph, the China Daily later reported that the Great Wall can be seen from space with the naked eye, under favorable viewing conditions, if one knows exactly where to look. However, the resolution of a camera can be much higher than the human visual system, and the optics much better, rendering photographic evidence irrelevant to the issue of whether it is visible to the naked eye.

2011-04-27T08:28:00.000-07:00

Allergy

Allergic or hypersensitivity type I is the failure of immune body where one's body becomes hypersensitive in immunology react to the materials generally immunogenic (antigenic) or the person in question is said to be atopic. In other words, the human body to the environment or excessive berkasi materials by the body are considered foreign and dangerous, but it was not for people who are not atopic. Ingredients that cause hypersensitivity is called an allergen .

Allergies are caused by the production of antibodies of IgE type.

Prevention

Some things you can do to prevent allergies:

§ Maintain cleanliness of the environment, both inside and outside the home. This includes not accumulate a lot of stuff in the home or bedroom can become a den of dust accumulation as a stimulus alergi.Usahakan reactions do not keep animals in the house or put a pet cage around your home.

§ Personal hygiene must also be considered, to avoid climbing tertumpuknya which can also be a source of stimulation alergi.Untuk reaction bath, it should use warm water for life, and try to shower the evening before PK.17.00 '. Soap and shampoo are used should be that soap and shampoo to bayi.Dilarang using hair dye.

§ Do not use air freshener or perfume, anti-mosquito drugs. If in your house there are lots of mosquitoes, use anti-mosquito racket.

§ Use a mattress or cushion of foam material, not cotton.

§ Use of cotton bed sheets and wash them at least once a week with warm water will be effective.

§ Avoid using the clothes made from wool, use cotton clothing.

§ Air conditioning (AC) can be used, but should not be too cold and should not be more than PK.24.00 '

§ Keep an eye on any food or beverages or drugs that cause allergic reactions. Avoid food, beverages, and drugs such. You must comply with the rules of your allergy diet.

§ meet the experts. Consult a specialist. Allergies that arise require different treatments to each patient allergies. Ask your doctor to perform immunotherapy to reduce your sensitivity to substances trigger allergic reactions, for example: by using the extract of house dust injection or by performing immunization Guirine Baccillus Calmette (BCG) at least 3 times (1 time a month) in succession, and repeated every 6 months.

STUXNET(new dangour for modren world)

2010-12-29T20:13:00.000-08:00

Stuxnet is a Windows-specific computer worm first discovered in July 2010 by VirusBlokAda, a security firm based in Belarus. While it is not the first time that hackers have targeted industrial systems, it is the first discovered worm that spies on and reprograms industrial systems, and the first to include a programmable logic controller (PLC) rootkit. It was specifically written to attack Supervisory Control And Data Acquisition (SCADA) systems used to control and monitor industrial processes. Stuxnet includes the capability to reprogram the PLCs and hide its changes.
The worm's probable target is said to have been high value infrastructures in Iran using Siemens control systems. According to news reports the infestation by this worm might have damaged Iran's nuclear facilities in Natanz and eventually delayed the start up of Iran's Bushehr Nuclear Power Plant. Although Siemens has stated that the worm has not caused any damage, on November 29, Iran confirmed that its nuclear program had indeed been damaged by Stuxnet.
Russian digital security company Kaspersky Labs released a statement that described Stuxnet as "a working and fearsome prototype of a cyber-weapon that will lead to the creation of a new arms race in the world." Kevin Hogan, Senior Director of Security Response at Symantec, noted that 60% of the infected computers worldwide were in Iran, suggesting its industrial plants were the target. Kaspersky Labs concluded that the attacks could only have been conducted "with nation-state support", making Iran the first target of real cyberwarfare.
History
The worm was first reported by the security company VirusBlokAda in mid-June 2010, and roots of it have been traced back to June 2009. It contains a component with a build time stamp from 3 February 2010. In the United Kingdom on 25 November 2010, Sky News reported that it had received information that the Stuxnet worm, or a variation of the virus, had been traded on the black market. The name is derived from some keywords discovered in the software.
Affected countries
A study of the spread of Stuxnet by Symantec showed that the main affected countries as of August 6, 2010 were:
Country Infected computers
China 6,000,000 (unconfirmed) (October 1)
Iran 62,867
Indonesia 13,336
India 6,552
United States 2,913
Australia 2,436
United Kingdom 1,038
Malaysia 1,013
Pakistan 993
Finland 7
Germany 5 (September)
Operation
The complexity of the software is very unusual for malware, and consists of attacks against three different systems:
1. The Windows operating system,
2. An industrial software application that runs on Windows, and
3. A Siemens programmable logic controller (PLC).
The attack requires in-depth knowledge of industrial processes and an interest in attacking industrial infrastructure. These capabilities would have required a team of people to program, as well as check that the malware would not crash the PLCs. Eric Byres, who has years of experience maintaining and troubleshooting Siemens systems, told Wired that writing the code would have taken many man-months, if not years.
Windows infection
Stuxnet attacked Windows systems using four zero-day attacks (plus the CPLINK vulnerability and a vulnerability used by the Conficker worm). It is initially spread using infected removable drives such as USB flash drives, and then uses other exploits and techniques such as peer-to-peer RPC to infect and update other computers inside private networks that are not directly connected to the Internet. The number of zero-day Windows exploits used is unusual, as zero-day Windows exploits are valued, and hackers do not normally waste the use of four different ones in the same worm. Stuxnet is unusually large at half a megabyte in size, and written in different programming languages (including C and C++) which is also irregular for malware. The Windows component of the malware is promiscuous in that it spreads relatively quickly and indiscriminately.
The malware has both user-mode and kernel-mode rootkit capability under Windows, and its device drivers have been digitally signed with the private keys of two certificates that were stolen from separate companies, JMicron and Realtek, that are both located at Hsinchu Science Park in Taiwan. The driver signing helped it install kernel-mode drivers successfully and remain undetected for a relatively long period of time. Both compromised certificates have been revoked by VeriSign.
Two websites were configured as command and control servers for the malware, allowing it to be updated, and for industrial espionage to be conducted by uploading information. Both of these websites have subsequently been taken down as part of a global effort to disable the malware.
Step 7 software infection

Overview of normal communications between Step 7 and a Siemens PLC

Overview of Stuxnet hijacking communication between Step 7 software and a Siemens PLC
Once installed on a Windows system, Stuxnet infects project files belonging to Siemens' WinCC/PCS 7 SCADA control software (Step 7), and subverts a key communication library of WinCC called s7otbxbx.dll. The purpose of this subversion is to intercept communications between the WinCC software running under Windows and the target Siemens PLC devices that the software is able to configure and program when the two are connected via a data cable. In this way, the malware is able to install itself on PLC devices unnoticed, and subsequently to mask its presence from WinCC if the control software attempts to read an infected block of memory from the PLC system.

The malware furthermore used a zero-day exploit in the WinCC/SCADA database software in the form of a hard-coded database password.
PLC infection
Siemens Simatic S7-300 PLC CPU with three modules attached, each of which can control 31 slave variable-frequency drives
The entirety of the Stuxnet code has not yet been understood, but among its peculiar capabilities is a fingerprinting technology which allows it to precisely identify the systems it infects. Stuxnet requires specific slave variable-frequency drives (frequency converter drives) to be attached to the targeted Siemens S7-300 system and its associated modules. It only attacks those PLC systems with variable-frequency drives from two specific vendors: Vacon based in Finland and Fararo Paya based in Iran. Furthermore, it monitors the frequency of the attached motors, and only attacks systems that spin between 807Hz and 1210 Hz. The industrial applications of motors with these parameters are diverse, and may include pumps or centrifuges.
Stuxnet installs malware into memory block DB890 of the PLC that monitors the Profibus messaging bus of the system. When certain criteria are met, it periodically modifies the frequency to 1410 Hz and then to 2 Hz and then to 1064 Hz, and thus affects the operation of the connected motors by changing their rotational speed. It also installs a rootkit that hides the malware on the system—the first such documented case on this platform.
Removal
Siemens has released a detection and removal tool for Stuxnet. Siemens recommends contacting customer support if an infection is detected and advises installing Microsoft patches for security vulnerabilities and prohibiting the use of third-party USB flash drives Siemens also advises immediately upgrading password access codes.
The worm's ability to reprogram external programmable logic controllers (PLCs) may complicate the removal procedure. Symantec's Liam O'Murchu warns that fixing Windows systems may not completely solve the infection; a thorough audit of PLCs is recommended. Despite speculation that incorrect removal of the worm could cause damage, Siemens reports that in the first four months since discovery, the malware was successfully removed from the systems of twenty-two customers without any adverse impact.
Control system security
Main article: Control system security
Prevention of control system security incidentssuch as from viral infections like Stuxnet, is a topic that is being addressed in both the public and the private sector.
The U.S. Department of Homeland Security National Cyber Security Division operates the Control System Security Program (CSSP). The program operates a specialized Computer Emergency Response Team (ICS-CERT), conducts a biannual conference (ICSJWG), provides training, publishes recommended practices, and provides a self-assessment tool.
Several industry organizations and professional societies have published standards and best practice guidelines providing direction and guidance for control system end-users on how to establish a Control System Security management program. The basic premise that all of these documents share is that prevention requires a multi-layered approach, often referred to as "defense-in-depth". The layers include policies & procedures, awareness & training, network segmentation, access control measures, physical security measures, system hardening, e.g., patch management, and system monitoring, anti-virus and IPS. The standards and best practices also all recommend starting with a risk analysis and a control system security assessment. The purpose is to assess the current level of risk and the size of the gap between that risk and what is tolerable. The other purpose of an assessment is to identify the vulnerabilities and develop a prioritized program to eliminate or minimize them.
In response to these concerns, cyber security standards and certifications programs such as ISA 99 and SASecure have been developed to evaluate and certify the security of industrial automation products.
Automation, SCADA and control system developers often use off-the-shelf equipment, software and protocols, integrating and configuring these in different ways for a variety of applications. This "common" approach can make it easier for malware to bring down some vulnerable systems. However, proprietary automation, SCADA and control system developers are able to provide a completely bespoke solution, using new protocols and hardware/software/firmware solutions yet unknown to developers of malware.
Speculations about the target and origin
Symantec estimates that the group developing Stuxnet would have been well-funded, consisting of five to ten people, and would have taken six months to prepare. The Guardian, the BBC and The New York Times all reported that experts studying Stuxnet considered that the complexity of the code indicates that only a nation state would have the capabilities to produce it.
Israel, perhaps through Unit 8200, has been speculated to be the country behind Stuxnet in many media reports and by experts such as Richard Falkenrath, former Senior Director for Policy and Plans within the United States Department of Homeland Security. Some have also referred to several clues in the code such as a concealed reference to the word "MYRTUS", believed to refer to the Myrtle tree, or Hadassah in Hebrew. Hadassah was the birth name of the former Jewish queen of Persia, Queen Esther. However, it may be that the "MYRTUS" reference is simply a misinterpreted reference to SCADA components known as RTUs (Remote Terminal Units) and that this reference is actually "My RTUs"–a management feature of SCADA. Also, the number 19790509 appears once in the code and might refer to the date "1979 May 09", the day Habib Elghanian, a Persian Jew, was executed in Tehran. "Symantec cautions readers on drawing any attribution conclusions. Attackers would have the natural desire to implicate another party." According to the New York Times, a former member of the United States intelligence community speculated that the attack may have been the work of Unit 8200. Yossi Melman, who covers intelligence for the Israeli daily newspaper Haaretz and is at work on a book about Israeli intelligence, also suspected that Israel was involved. He noted that Meir Dagan, head of the national intelligence agency Mossad, had his term extended in 2009 because he was said to be involved in important projects. Additionally, in the past year Israeli estimates of when Iran will have a nuclear weapon had been extended to 2014. "They seem to know something, that they have more time than originally thought”, he added.
Additionally, in 2009, a year before Stuxnet was discovered, Scott Borg of the United States Cyber-Consequences Unit (US-CCU) had suggested that Israel might prefer to mount a cyber-attack rather than a military strike on Iran's nuclear facilities. According to Borg this kind of attack could involve disrupting sensitive equipment such as centrifuges using malware introduced via infected memory sticks: "Since the autumn of 2002, I have regularly predicted that this sort of cyber-attack tool would eventually be developed ... Israel certainly has the ability to create Stuxnet and there is little downside to such an attack, because it would be virtually impossible to prove who did it. So a tool like Stuxnet is Israel's obvious weapon of choice." There has also been speculation on the involvement of NATO, the United States and other Western nations. It has been reported that the United States, under one of its most secret programs, initiated by the Bush administration and accelerated by the Obama administration, has sought to destroy Iran's nuclear program by novel methods such as undermining Iranian computer systems. However, solid evidence pointing to Western (and specifically American) involvement has been scarce.
Though Israel has not publicly commented on the Stuxnet attack, it has since confirmed that cyberwarfare is now among the pillars of its defense doctrine, with a military intelligence unit set up to pursue both defensive and offensive options.
Symantec has reported that the majority of infected systems were in Iran (about 60%),which has led to speculation that it may have been deliberately targeting "high-value infrastructure" in Iran including either the Bushehr Nuclear Power Plant or the Natanz nuclear facility. Ralph Langner, a German cyber-security researcher, called the malware "a one-shot weapon" and said that the intended target was probably hit, although he admitted this was speculation.
There are reports that Iran's uranium enrichment facility at Natanz was the target of Stuxnet and the site sustained damage because of it, causing a sudden 15% reduction in its production capabilities. There was also a previous report by WikiLeaks disclosing a "serious nuclear accident" at the site in 2009. According to statistics published by the Federation of American Scientists (FAS) the number of enriched centrifuges operational in Iran mysteriously declined from about 4,700 to about 3,900 beginning around the time the nuclear incident WikiLeaks mentioned would have occurred. On November 23 it was announced that uranium production at Natanz in Iran temporarily ceased altogether because of a series of major technical problems. According to a report by the Institute for Science and International Security (ISIS) Stuxnet is "a reasonable explanation for the apparent damage" at Natanz and may have destroyed up to 1000 centrifuges (10 percent) in the months before January 2010. The authors conclude:
"The attacks seem designed to force a change in the centrifuge’s rotor speed, first raising the speed and then lowering it, likely with the intention of inducing excessive vibrations or distortions that would destroy the centrifuge. If its goal was to quickly destroy all the centrifuges in the FEP, Stuxnet failed. But if the goal was to destroy a more limited number of centrifuges and set back Iran’s progress in operating the FEP, while making detection difficult, it may have succeeded, at least temporarily."
The ISIS report further notes that Iranian authorities have attempted to conceal the breakdown by installing new centrifuges on a large scale.
Iranian reaction
The Associated Press reported that the semi-official Iranian Students News Agency released a statement on 24 September 2010 stating that experts from the Atomic Energy Organization of Iran met in the previous week to discuss how Stuxnet could be removed from their systems. According to analysts, Western intelligence agencies have been attempting to sabotage the Iranian nuclear program for some time.
The head of the Bushehr Nuclear Power Plant told Reuters that only the personal computers of staff at the plant had been infected by Stuxnet and the state-run newspaper Iran Daily quoted Reza Taghipour, Iran's telecommunications minister, as saying that it had not caused "serious damage to government systems". The Director of Information Technology Council at the Iranian Ministry of Industries and Mines, Mahmud Liaii, has said that: "An electronic war has been launched against Iran... This computer worm is designed to transfer data about production lines from our industrial plants to locations outside Iran."
It is believed that infection originated from Russian laptops belonging to Russian contractors at the site of Bushehr power plant and spreading from there with the aim of targeting the power plant control systems. In response to the infection, Iran has assembled a team to combat it. With more than 30,000 IP addresses affected in Iran, an official has said that the infection is fast spreading in Iran and the problem has been compounded by the ability of Stuxnet to mutate. Iran has set up its own systems to clean up infections and has advised against using the Siemens SCADA antivirus since it is suspected that the antivirus is actually embedded with codes which update Stuxnet instead of eradicating it.
According to Hamid Alipour, deputy head of Iran's government Information Technology Company, "The attack is still ongoing and new versions of this virus are spreading." He reports that his company had begun the cleanup process at Iran's "sensitive centres and organizations. We had anticipated that we could root out the virus within one to two months, but the virus is not stable, and since we started the cleanup process three new versions of it have been spreading," he told the Islamic Republic News Agency.
Although he did not mention Stuxnet by name, on Monday November 29, 2010, Iranian President Mahmoud Ahmadinejad for the first time admitted that malicious software code had damaged Iran's centrifuge facilities. "They succeeded in creating problems for a limited number of our centrifuges with the software they had installed in electronic parts," Mr. Ahmadinejad told reporters at a news conference, Reuters reported. "They did a bad thing. Fortunately our experts discovered that and today they are not able [to do that] anymore.
On the same day two Iranian nuclear scientists were assassinated when bombs were attached to their cars in Tehran. Wired speculated that the assassinations could indicate that whoever was behind Stuxnet felt that it was not sufficient to stop the nuclear program.

HIV AND AIDS

2010-12-01T07:14:00.000-08:00

What Is It?

AIDS is one of the most serious, deadly diseases in human history.

More than 20 years ago, doctors in the United States identified the first cases of AIDS in San Francisco and New York. Now there are an estimated 42 million people living with HIV or AIDS worldwide, and more than 3 million die every year from AIDS-related illnesses.

AIDS is caused by the human immunodeficiency virus (HIV). HIV destroys a type of defense cell in the body called a CD4 helper lymphocyte (pronounced: lim-fuh-site). These lymphocytes are part of the body's immune system, the defense system that fights infectious diseases. But as HIV destroys these lymphocytes, people with the virus begin to get serious infections that they normally wouldn't — that is, they become immune deficient. The name for this condition is acquired immunodeficiency syndrome(AIDS).

As the medical community learns more about how HIV works, they've been able to develop drugs to inhibit it (meaning they interfere with its growth). These drugs have been successful in slowing the progress of the disease, and people with the disease now live much longer. But there is still no cure for HIV and AIDS.

Hundreds of U.S. teens become infected with HIV each year. HIV can be transmitted from an infected person to another person through blood, semen (also known as "cum," the fluid released from the penis when a male ejaculates), vaginal fluids, and breast milk.

The virus is spread through high-risk behaviors including:

· unprotected oral, vaginal, or anal sexual intercourse ("unprotected" means not using a condom)

· sharing needles, such as needles used to inject drugs (including needles used for injecting steroids) and those used for tattooing

People who have another sexually transmitted disease, such as syphilis, genital herpes, chlamydia, gonorrhea, or bacterial vaginosis are at greater risk for getting HIV during sex with infected partners.

If a woman with HIV is pregnant, her newborn baby can catch the virus from her before birth, during the birthing process, or from breastfeeding. If doctors know an expectant mother has HIV, they can usually prevent the spread of the virus from mother to baby. All pregnant teens and women should be tested for HIV so they can begin treatment if necessary.

How Does HIV Affect the Body?

A healthy body is equipped with CD4 helper lymphocyte cells (CD4 cells). These cells help the immune system function normally and fight off certain kinds of infections. They do this by acting as messengers to other types of immune system cells, telling them to become active and fight against an invading germ.

HIV attaches to these CD4 cells, infects them, and uses them as a place to multiply. In doing so, the virus destroys the ability of the infected cells to do their job in the immune system. The body then loses the ability to fight many infections.

Because their immune systems are weakened, people who have AIDS are unable to fight off many infections, particularly tuberculosis and other kinds of otherwise rare infections of the lung (such as Pneumocystis carinii pneumonia), the surface covering of the brain (meningitis), or the brain itself (encephalitis). People who have AIDS tend to keep getting sicker, especially if they are not taking antiviral medications properly.

AIDS can affect every body system. The immune defect caused by having too few CD4 cells also permits some cancers that are stimulated by viral illness to occur — some people with AIDS get forms of lymphoma and a rare tumor of blood vessels in the skin called Kaposi's sarcoma. Because AIDS is fatal, it's important that doctors detect HIV infection as early as possible so a person can take medication to delay the onset of AIDS.

How Do People Know They Have HIV?

Once a person's blood lacks the number of CD4 cells required to fight infections, or the person has signs of specific illnesses or diseases that occur in people with HIV infection, doctors make a diagnosis of AIDS.

Severe symptoms of HIV infection and AIDS may not appear for 10 years. And for years leading up to that, a person may not have symptoms of AIDS. The amount of time it takes for symptoms of AIDS to appear varies from person to person. Some people may feel and look healthy for years while they are infected with HIV. It is still possible to infect others with HIV, even if the person with the virus has absolutely no symptoms. You cannot tell simply by looking at someone whether he or she is infected.

When a person's immune system is overwhelmed by AIDS, the symptoms can include:

· extreme weakness or fatigue

· rapid weight loss

· frequent fevers that last for several weeks with no explanation

· heavy sweating at night

· swollen lymph glands

· minor infections that cause skin rashes and mouth, genital, and anal sores

· white spots in the mouth or throat

· chronic diarrhea

· a cough that won't go away

· trouble remembering things

Girls may also experience severe vaginal yeast infections that don't respond to usual treatment, as well as pelvic inflammatory disease (PID).

How Can It Be Prevented?

One of the reasons that HIV is so dangerous is that a person can have the virus for a long time without knowing it. That person can then spread the virus to others through high-risk behaviors. HIV transmission can be prevented by:

· abstaining from sex (not having oral, vaginal, or anal sex)

· always using latex condoms for all types of sexual intercourse

· avoiding contact with the bodily fluids through which HIV is transmitted

· never sharing needles

How Do Doctors Test for and Treat HIV?

If you think that you may have HIV or AIDS or if you have had a partner who may have HIV or AIDS, see your family doctor, adolescent doctor, or gynecologist. He or she will talk with you and perform tests. The doctor may do a blood test or a swab of the inside of your cheek. Depending on what type of test is done, results may take from a few hours to several days. Let the doctor know the best way to reach you confidentially with any test results.

People can also get tested for HIV/AIDS at special AIDS clinics around the country. Clinics offer both anonymous (meaning the clinic doesn't know a person's name) and confidential (meaning they know who a person is but keep it private) testing. Most AIDS testing centers will ask you to follow up for counseling to get your results, whether the test is negative or positive.

If you're not sure how to find a doctor or get an AIDS test, you can contact the National AIDS Hotlines at (800) 342-AIDS (English) or (800) 344-7432 (Spanish). A specialist there will explain what you should do next.

There is no cure for AIDS, which makes prevention so important. Combinations of antiviral drugs and drugs that boost the immune system have allowed many people with HIV to resist infections, stay healthy, and prolong their lives, but these medications are not a cure. Right now there is no vaccine to prevent HIV and AIDS, although researchers are working on developing one.

DIABETES MELLITUS

2010-11-22T22:19:00.001-08:00

DIABETES MELLITUS

Diabetes mellitus, often simply referred to as diabetes—is a group of metabolic diseases in which a person has high blood sugar, either because the body does not produce enough insulin, or because cells do not respond to the insulin that is produced. This high blood sugar produces the classical symptoms of polyuria (frequent urination), polydipsia (increased thirst) andpolyphagia (increased hunger).
There are three main types of diabetes:
 Type 1 diabetes: results from the body's failure to produce insulin, and presently requires the person to inject insulin. (Also referred to as insulin-dependent diabetes mellitus, IDDM for short, and juvenile diabetes.)
 Type 2 diabetes: results from insulin resistance, a condition in which cells fail to use insulin properly, sometimes combined with an absolute insulin deficiency.
 Gestational diabetes: is when pregnant women, who have never had diabetes before, have a high blood glucose level during pregnancy. It may precede development of type 2 DM.
Other forms of diabetes mellitus include congenital diabetes, which is due to genetic defects of insulin secretion, cystic fibrosis-related diabetes, steroid diabetes induced by high doses of glucocorticoids, and several forms of monogenic diabetes.
All forms of diabetes have been treatable since insulin became available in 1921, and type 2 diabetes may be controlled with medications. Both type 1 and 2 are chronic conditions that usually cannot be cured. Pancreas transplants have been tried with limited success in type 1 DM; gastric bypass surgery has been successful in many with morbid obesity and type 2 DM. Gestational diabetes usually resolves after delivery. Diabetes without proper treatments can cause many complications. Acute complications include hypoglycemia, diabetic ketoacidosis, or nonketotic hyperosmolar coma. Serious long-term complications include cardiovascular disease, chronic renal failure, retinal damage. Adequate treatment of diabetes is thus important, as well as blood pressure control and lifestyle factors such as smoking cessation and maintaining a healthy body weight.
As of 2000 at least 171 million people worldwide suffer from diabetes, or 2.8% of the population. Type 2 diabetes is by far the most common, affecting 90 to 95% of the U.S. diabetes population.
Definition
The term diabetes, without qualification, usually refers to diabetes mellitus, which roughly translates to excessive sweet urine (known as "glycosuria"). Several rare conditions are also named diabetes. The most common of these is diabetes insipidus in which large amounts of urine are produced (polyuria), which is not sweet (insipidus meaning "without taste" in Latin).
The term "type 1 diabetes" has replaced several former terms, including childhood-onset diabetes, juvenile diabetes, and insulin-dependent diabetes mellitus (IDDM). Likewise, the term "type 2 diabetes" has replaced several former terms, including adult-onset diabetes, obesity-related diabetes, and non-insulin-dependent diabetes mellitus (NIDDM). Beyond these two types, there is no agreed-upon standard nomenclature. Various sources have defined "type 3 diabetes" as: gestational diabetes, insulin-resistant type 1 diabetes (or "double diabetes"), type 2 diabetes which has progressed to require injected insulin, and latent autoimmune diabetes of adults (or LADA or "type 1.5" diabetes)
Classification
Most cases of diabetes mellitus fall into three broad categories: type 1, type 2, and gestational diabetes. A few other types are described.
Type 1 diabetes
Type 1 diabetes mellitus is characterized by loss of the insulin-producing beta cells of the islets of Langerhans in the pancreas leading to insulin deficiency. This type of diabetes can be further classified as immune-mediated or idiopathic. The majority of type 1 diabetes is of the immune-mediated nature, where beta cell loss is a T-cell mediated autoimmune attack. There is no known preventive measure against type 1 diabetes, which causes approximately 10% of diabetes mellitus cases in North America and Europe. Most affected people are otherwise healthy and of a healthy weight when onset occurs. Sensitivity and responsiveness to insulin are usually normal, especially in the early stages. Type 1 diabetes can affect children or adults but was traditionally termed "juvenile diabetes" because it represents a majority of the diabetes cases in children.
Type 2 diabetes
Type 2 diabetes mellitus is characterized by insulin resistance which may be combined with relatively reduced insulin secretion. The defective responsiveness of body tissues to insulin is believed to involve the insulin receptor. However, the specific defects are not known. Diabetes mellitus due to a known defect are classified separately. Type 2 diabetes is the most common type.
In the early stage of type 2 diabetes, the predominant abnormality is reduced insulin sensitivity. At this stage hyperglycemia can be reversed by a variety of measures and medications that improve insulin sensitivity or reduce glucose production by the liver.
Gestational diabetes
Gestational diabetes mellitus (GDM) resembles type 2 diabetes in several respects, involving a combination of relatively inadequate insulin secretion and responsiveness. It occurs in about 2%–5% of all pregnancies and may improve or disappear after delivery. Gestational diabetes is fully treatable but requires careful medical supervision throughout the pregnancy. About 20%–50% of affected women develop type 2 diabetes later in life.
Even though it may be transient, untreated gestational diabetes can damage the health of the fetus or mother. Risks to the baby include macrosomia (high birth weight), congenital cardiac and central nervous system anomalies, and skeletal muscle malformations. Increased fetal insulin may inhibit fetal surfactant production and cause respiratory distress syndrome. Hyperbilirubinemia may result from red blood cell destruction. In severe cases, perinatal death may occur, most commonly as a result of poor placental perfusion due to vascular impairment. Labor may be indicated with decreased placental function. A cesarean section may be performed if there is marked fetal distress or an increased risk of injury associated with macrosomia, such as shoulder dystocia.
A 2008 study completed in the U.S. found that the number of American women entering pregnancy with preexisting diabetes is increasing. In fact the rate of diabetes in expectant mothers has more than doubled in the past 6 years. This is particularly problematic as diabetes raises the risk of complications during pregnancy, as well as increasing the potential that the children of diabetic mothers will also become diabetic in the future.
Other types
Pre-diabetes indicates a condition that occurs when a person's blood glucose levels are higher than normal but not high enough for a diagnosis of type 2 diabetes. Many people destined to develop type 2 diabetes spend many years in a state of pre-diabetes which has been termed "America's largest healthcare epidemic.
Some cases of diabetes are caused by the body's tissue receptors not responding to insulin (even when insulin levels are normal, which is what separates it from type 2 diabetes); this form is very uncommon. Genetic mutations (autosomal or mitochondrial) can lead to defects in beta cell function. Abnormal insulin action may also have been genetically determined in some cases. Any disease that causes extensive damage to the pancreas may lead to diabetes (for example, chronic pancreatitis and cystic fibrosis). Diseases associated with excessive secretion of insulin-antagonistic hormones can cause diabetes (which is typically resolved once the hormone excess is removed). Many drugs impair insulin secretion and some toxins damage pancreatic beta cells. The ICD-10 (1992) diagnostic entity, malnutrition-related diabetes mellitus (MRDM or MMDM, ICD-10 code E12), was deprecated by the World Health Organization when the current taxonomy was introduced in 1999.
Following is a comprehensive list of other causes of diabetes:
 Genetic defects of β-cell Function
 Maturity onset diabetes of the young (MODY)
 Mitochondrial DNA mutations
 Genetic defects in insulin processing or insulin action
 Defects in proinsulin conversion
 Insulin gene mutations
 Insulin receptor mutations
 Exocrine Pancreatic Defects
 Chronic pancreatitis
 Pancreatectomy
 Pancreatic neoplasia
 Cystic fibrosis
 Hemochromatosis
 Fibrocalculous pancreatopathy
 Endocrinopathies
 Growth hormone excess (acromegaly)
 Cushing syndrome
 Hyperthyroidism
 Pheochromocytoma
 Glucagonoma
 Infections
 Cytomegalovirus infection
 Coxsackievirus B
 Drugs
 Glucocorticoids
 Thyroid hormone
 β-adrenergic agonists

Signs and symptoms

Overview of the most significant symptoms of diabetes.
The classical symptoms of diabetes are polyuria (frequent urination), polydipsia (increased thirst) and polyphagia (increased hunger). Symptoms may develop rapidly (weeks or months) in type 1 diabetes while in type 2 diabetes they usually develop much more slowly and may be subtle or absent.
Prolonged high blood glucose causes glucose absorption, which leads to changes in the shape of the lenses of the eyes, resulting in vision changes; sustained sensible glucose control usually returns the lens to its original shape. Blurred vision is a common complaint leading to a diabetes diagnosis; type 1 should always be suspected in cases of rapid vision change, whereas with type 2 change is generally more gradual, but should still be suspected.
People (usually with type 1 diabetes) may also present with diabetic ketoacidosis, a state of metabolic dysregulation characterized by the smell of acetone; a rapid, deep breathing known as Kussmaul breathing; nausea; vomiting and abdominal pain; and an altered states of consciousness.
A rarer but equally severe possibility is hyperosmolar nonketotic state, which is more common in type 2 diabetes and is mainly the result of dehydration. Often, the patient has been drinking extreme amounts of sugar-containing drinks, leading to a vicious circle in regard to the water loss.
A number of skin rashes can occur in diabetes that are collectively known as diabetic dermadromes.
Causes
The cause of diabetes depends on the type. Type 2 diabetes is due primarily to lifestyle factors and genetics.
Type 1 diabetes is also partly inherited and then triggered by certain infections, with some evidence pointing at Coxsackie B4 virus. There is a genetic element in individual susceptibility to some of these triggers which has been traced to particular HLA genotypes (i.e., the genetic "self" identifiers relied upon by the immune system). However, even in those who have inherited the susceptibility, type 1 diabetes mellitus seems to require an environmental trigger.
Pathophysiology

The fluctuation of blood sugar (red) and the sugar-lowering hormone insulin (blue) in humans during the course of a day with three meals. One of the effects of a sugar-rich vs a starch-rich meal is highlighted.

Mechanism of insulin release in normal pancreatic beta cells. Insulin production is more or less constant within the beta cells, irrespective of blood glucose levels. It is stored within vacuoles pending release, via exocytosis, which is primarily triggered by food, chiefly food containing absorbable glucose. The chief trigger is a rise in blood glucose levels after eating
Insulin is the principal hormone that regulates uptake of glucose from the blood into most cells (primarily muscle and fat cells, but not central nervous system cells). Therefore deficiency of insulin or the insensitivity of its receptors plays a central role in all forms of diabetes mellitus.
Humans are capable of digesting some carbohydrates, in particular those most common in food; starch, and some disaccharides such as sucrose, are converted within a few hours to simpler forms most notably the monosaccharide glucose, the principal carbohydrate energy source used by the body. The rest are passed on for processing by gut flora largely in the colon. Insulin is released into the blood by beta cells (β-cells), found in the Islets of Langerhans in the pancreas, in response to rising levels of blood glucose, typically after eating. Insulin is used by about two-thirds of the body's cells to absorb glucose from the blood for use as fuel, for conversion to other needed molecules, or for storage.
Insulin is also the principal control signal for conversion of glucose to glycogen for internal storage in liver and muscle cells. Lowered glucose levels result both in the reduced release of insulin from the beta cells and in the reverse conversion of glycogen to glucose when glucose levels fall. This is mainly controlled by the hormone glucagon which acts in the opposite manner to insulin. Glucose thus forcibly produced from internal liver cell stores (as glycogen) re-enters the bloodstream; muscle cells lack the necessary export mechanism. Normally liver cells do this when the level of insulin is low (which normally correlates with low levels of blood glucose).
Higher insulin levels increase some anabolic ("building up") processes such as cell growth and duplication, protein synthesis, and fat storage. Insulin (or its lack) is the principal signal in converting many of the bidirectional processes of metabolism from a catabolic to an anabolic direction, and vice versa. In particular, a low insulin level is the trigger for entering or leaving ketosis (the fat burning metabolic phase).
If the amount of insulin available is insufficient, if cells respond poorly to the effects of insulin (insulin insensitivity or resistance), or if the insulin itself is defective, then glucose will not have its usual effect so that glucose will not be absorbed properly by those body cells that require it nor will it be stored appropriately in the liver and muscles. The net effect is persistent high levels of blood glucose, poor protein synthesis, and other metabolic derangements, such as acidosis.
When the glucose concentration in the blood is raised beyond its renal threshold (about 10 mmol/L, although this may be altered in certain conditions, such as pregnancy), reabsorption of glucose in the proximal renal tubuli is incomplete, and part of the glucose remains in the urine (glycosuria). This increases the osmotic pressure of the urine and inhibits reabsorption of water by the kidney, resulting in increased urine production (polyuria) and increased fluid loss. Lost blood volume will be replaced osmotically from water held in body cells and other body compartments, causing dehydration and increased thirst.
Diagnosis
2006 WHO Diabetes criteria edit

Condition 2 hour glucose Fasting glucose
mmol/l(mg/dl) mmol/l(mg/dl)
Normal <7.8 (<140) <6.1 (<110)
Impaired fasting glycaemia <7.8 (<140) ≥ 6.1(≥110) & <7.0(<126)
Impaired glucose tolerance ≥7.8 (≥140) <7.0 (<126)
Diabetes mellitus ≥11.1 (≥200) ≥7.0 (≥126)
Diabetes mellitus is characterized by recurrent or persistent hyperglycemia, and is diagnosed by demonstrating any one of the following:
 Fasting plasma glucose level ≥ 7.0 mmol/L (126 mg/dL).
 Plasma glucose ≥ 11.1 mmol/L (200 mg/dL) two hours after a 75 g oral glucose load as in aglucose tolerance test.
 Symptoms of hyperglycemia and casual plasma glucose ≥ 11.1 mmol/L (200 mg/dL).
 Glycated hemoglobin (Hb A1C) ≥ 6.5%.
A positive result, in the absence of unequivocal hyperglycemia, should be confirmed by a repeat of any of the above-listed methods on a different day. It is preferable to measure a fasting glucose level because of the ease of measurement and the considerable time commitment of formal glucose tolerance testing, which takes two hours to complete and offers no prognostic advantage over the fasting test. According to the current definition, two fasting glucose measurements above 126 mg/dL (7.0 mmol/L) are considered diagnostic for diabetes mellitus.
People with fasting glucose levels from 100 to 125 mg/dL (5.6 to 6.9 mmol/L) are considered to have impaired fasting glucose. Patients with plasma glucose at or above 140 mg/dL (7.8 mmol/L), but not over 200 mg/dL (11.1 mmol/L), two hours after a 75 g oral glucose load are considered to have impaired glucose tolerance. Of these two pre-diabetic states, the latter in particular is a major risk factor for progression to full-blown diabetes mellitus as well as cardiovascular disease.
Management
Diabetes mellitus is a chronic disease which is difficult to cure. Management concentrates on keeping blood sugar levels as close to normal ("euglycemia") as possible without presenting undue patient danger. This can usually be with close dietary management, exercise, and use of appropriate medications (insulin only in the case of type 1 diabetes mellitus. Oral medications may be used in the case of type 2 diabetes, as well as insulin).
Patient education, understanding, and participation is vital since the complications of diabetes are far less common and less severe in people who have well-managed blood sugar levels. Wider health problems may accelerate the deleterious effects of diabetes. These includesmoking, elevated cholesterol levels, obesity, high blood pressure, and lack of regular exercise.
Lifestyle modifications
There are roles for patient education, dietetic support, sensible exercise, with the goal of keeping both short-term and long-term blood glucose levels within acceptable bounds. In addition, given the associated higher risks of cardiovascular disease, lifestyle modifications are recommended to control blood pressure.
Medications
Oral medications
Routine use of aspirin has not been found to improve outcomes in uncomplicated diabetes.
Insulin
Main article: Insulin therapy
Type 1 treatments usually include combinations of regular or NPH insulin, and/or synthetic insulin analogs.
Support
In countries using a general practitioner system, such as the United Kingdom, care may take place mainly outside hospitals, with hospital-based specialist care used only in case of complications, difficult blood sugar control, or research projects. In other circumstances, general practitioners and specialists share care of a patient in a team approach. Optometrists, podiatrists/chiropodists, dietitians, physiotherapists, nursing specialists (e.g., DSNs (Diabetic Specialist Nurse)), nurse practitioners, or Certified Diabetes Educators, may jointly provide multidisciplinary expertise. In countries where patients must provide for their own health care (e.g. in the US, and in much of the undeveloped world).
Peer support links people living with diabetes. Within peer support, people with a common illness share knowledge and experience that others, including many health workers, do not have. Peer support is frequent, ongoing, accessible and flexible and can take many forms—phone calls, text messaging, group meetings, home visits, and even grocery shopping. It complements and enhances other health care services by creating the emotional, social and practical assistance necessary for managing disease and staying healthy.
Prognosis
Diabetes doubles the risk of vascular problems, including cardiovascular disease.
According to one study, women with high blood pressure (hypertension) were three times more likely to develop type 2 diabetes as compared with women with optimal BP after adjusting for various factors such as age, ethnicity, smoking, alcohol intake, body mass index (BMI), exercise, family history of diabetes, etc. The study was conducted by researchers from the Brigham and Women’s Hospital, Harvard Medical School and the Harvard School of Public Health, USA, who followed over 38,000 female health professionals for ten years.
Except in the case of type 1 diabetes, which always requires insulin replacement, the way type 2 diabetes is managed may change with age. Insulin production decreases because of age-related impairment of pancreatic beta cells. Additionally, insulin resistance increases because of the loss of lean tissue and the accumulation of fat, particularly intra-abdominal fat, and the decreased tissue sensitivity to insulin. Glucose tolerance progressively declines with age, leading to a high prevalence of type 2 diabetes and postchallenge hyperglycemia in the older population. Age-related glucose intolerance in humans is often accompanied by insulin resistance, but circulating insulin levels are similar to those of younger people. Treatment goals for older patients with diabetes vary with the individual, and take into account health status, as well as life expectancy, level of dependence, and willingness to adhere to a treatment regimen. Glycated hemoglobin is better than fasting glucose for determining risks of cardiovascular disease and death from any cause.
Epidemiology

Prevalence of diabetes worldwide in 2000 (per 1000 inhabitants). World average was 2.8%.
no data ≤ 7.5 7.5–15 15–22.5 22.5–30 30–37.5 37.5–45 45–52.5 52.5–60 60–67.5 67.5–75 75–82.5 ≥ 82.5

Disability-adjusted life year for diabetes mellitus per 100,000 inhabitants in 2002.
no data ≤ 100 100-200 200-300 300-400 400-500 500-600 600-700 700-800 800-900 900-1000 1000-1500 ≥ 1500
In 2000, according to the World Health Organization, at least 171 million people worldwide suffer from diabetes, or 2.8% of the population. Its incidence is increasing rapidly, and it is estimated that by 2030, this number will almost double. Diabetes mellitus occurs throughout the world, but is more common (especially type 2) in the more developed countries. The greatest increase in prevalence is, however, expected to occur in Asia and Africa, where most patients will probably be found by 2030. The increase in incidence of diabetes in developing countries follows the trend of urbanization and lifestyle changes, perhaps most importantly a "Western-style" diet. This has suggested an environmental (i.e., dietary) effect, but there is little understanding of the mechanism(s) at present, though there is much speculation, some of it most compellingly presented.
For at least 20 years, diabetes rates in North America have been increasing substantially. In 2008 there were about 24 million people with diabetes in the United States alone, from those 5.7 million people remain undiagnosed. Other 57 million people are estimated to have pre-diabetes.
The Centers for Disease Control has termed the change an epidemic. The National Diabetes Information Clearinghouse estimates that diabetes costs $132 billion in the United States alone every year. About 5%–10% of diabetes cases in North America are type 1, with the rest being type 2. The fraction of type 1 in other parts of the world differs. Most of this difference is not currently understood. The American Diabetes Association cite the 2003 assessment of the National Center for Chronic Disease Prevention and Health Promotion (Centers for Disease Control and Prevention) that 1 in 3 Americans born after 2000 will develop diabetes in their lifetime.
According to the American Diabetes Association, approximately 18.3% (8.6 million) of Americans age 60 and older have diabetes. Diabetes mellitus prevalence increases with age, and the numbers of older persons with diabetes are expected to grow as the elderly population increases in number. The National Health and Nutrition Examination Survey (NHANES III) demonstrated that, in the population over 65 years old, 18% to 20% have diabetes, with 40% having either diabetes or its precursor form of impaired glucose tolerance.
Indigenous populations in first world countries have a higher prevalence and increasing incidence of diabetes than their corresponding non-indigenous populations. In Australia the age-standardised prevalence of self-reported diabetes in Indigenous Australians is almost 4 times that of non-indigenous Australians. Preventative community health programs such as Sugar Man (diabetes education) are showing some success in tackling this problem.
History
(pronounced /ˌdaɪ.əˈbiːtiːz/ or /ˌdaɪ.əˈbiːtɨs/;/mɨˈlaɪtəs/ or /ˈmɛlɨtəs/) was coined by Aretaeus of Cappadocia. It was derived from the Greek verb διαβαίνειν, diabaínein, itself formed from the prefix dia-, "across, apart," and the verb bainein, "to walk, stand." The verb diabeinein meant "to stride, walk, or stand with legs asunder"; hence, its derivative diabētēs meant "one that straddles," or specifically "a compass, siphon." The sense "siphon" gave rise to the use of diabētēs as the name for a disease involving the discharge of excessive amounts of urine. Diabetes is first recorded in English, in the form diabete, in a medical text written around 1425. In 1675, Thomas Willis added the word mellitus, from the Latinmeaning "honey", a reference to the sweet taste of the urine. This sweet taste had been noticed in urine by the ancient Greeks, Chinese, Egyptians, Indians, and Persians. In 1776, Matthew Dobson confirmed that the sweet taste was because of an excess of a kind of sugar in the urine and blood of people with diabetes.
Diabetes mellitus appears to have been a death sentence in the ancient era. Hippocrates makes no mention of it, which may indicate that he felt the disease was incurable. Aretaeus did attempt to treat it but could not give a good prognosis; he commented that "life (with diabetes) is short, disgusting and painful."
Sushruta (6th century BCE) identified diabetes and classified it as Medhumeha. He further identified it with obesity and sedentary lifestyle, advising exercises to help "cure" it. The ancient Indians tested for diabetes by observing whether ants were attracted to a person's urine, and called the ailment "sweet urine disease" (Madhumeha). The Chinese, Japanese and Korean words for diabetes are based on the same ideographs (糖尿病) which mean "sugar urine disease".
In medieval Persia, Avicenna (980–1037) provided a detailed account on diabetes mellitus in The Canon of Medicine, "describing the abnormal appetite and the collapse of sexual functions," and he documented the sweet taste of diabetic urine. Like Aretaeus before him, Avicenna recognized a primary and secondary diabetes. He also described diabetic gangrene, and treated diabetes using a mixture of lupine,trigonella (fenugreek), and zedoary seed, which produces a considerable reduction in the excretion of sugar, a treatment which is still prescribed in modern times. Avicenna also "described diabetes insipidus very precisely for the first time", though it was later Johann Peter Frank (1745–1821) who first differentiated between diabetes mellitus and diabetes insipidus.
Although diabetes has been recognized since antiquity, and treatments of various efficacies have been known in various regions since themiddle Ages, and in legend for much longer, pathogenesis of diabetes has only been understood experimentally since about 1900. The discovery of a role for the pancreas in diabetes is generally ascribed to Joseph von Mering and Oskar Minkowski, who in 1889 found that dogs whose pancreas was removed developed all the signs and symptoms of diabetes and died shortly afterwards. In 1910, Sir Edward Albert Sharpey-Schafer suggested that people with diabetes were deficient in a single chemical that was normally produced by the pancreas—he proposed calling this substance insulin, from the Latin insula, meaning island, in reference to the insulin-producing islets of Langerhansin the pancreas.
The endocrine role of the pancreas in metabolism, and indeed the existence of insulin, was not further clarified until 1921, when Sir Frederick Grant Banting and Charles Herbert Best repeated the work of Von Mering and Minkowski, and went further to demonstrate they could reverse induced diabetes in dogs by giving them an extract from the pancreatic islets of Langerhans of healthy dogs. Banting, Best, and colleagues (especially the chemist Collip) went on to purify the hormone insulin from bovine pancreases at the University of Toronto. This led to the availability of an effective treatment—insulin injections—and the first patient was treated in 1922. For this, Banting and laboratory director MacLeod received the Nobel Prize in Physiology or Medicine in 1923; both shared their Prize money with others in the team who were not recognized, in particular best and Collip. Banting and Best made the patent available without charge and did not attempt to control commercial production. Insulin production and therapy rapidly spread around the world, largely as a result of this decision. Banting is honored by World Diabetes Day which is held on his birthday, November 14.
The distinction between what is now known as type 1 diabetes and type 2 diabetes was first clearly made by Sir Harold Percival (Harry) Himsworth, and published in January 1936.
Despite the availability of treatment, diabetes has remained a major cause of death. For instance, statistics reveal that the cause-specificmortality rate during 1927 amounted to about 47.7 per 100,000 population in Malta.
Other landmark discoveries include:
 Identification of the first of the sulfonylureas in 1942
 Reintroduction of the use of biguanides for Type 2 diabetes in the late 1950s. The initial phenformin was withdrawn worldwide (in the U.S. in 1977) due to its potential for sometimes fatal lactic acidosis and metformin was first marketed in France in 1979, but not until 1994 in the US.
 The determination of the amino acid sequence of insulin (by Sir Frederick Sanger, for which he received a Nobel Prize)
 The radioimmunoassay for insulin, as discovered by Rosalyn Yalow and Solomon Berson (gaining Yalow the 1977 Nobel Prize in Physiology or Medicine)
 The three-dimensional structure of insulin (PDB 2INS)
 Dr Gerald Reaven's identification of the constellation of symptoms now called metabolic syndrome in 1988
 Demonstration that intensive glycemic control in type 1 diabetes reduces chronic side effects more as glucose levels approach 'normal' in a large longitudinal study, and also in type 2 diabetics in other large studies
 Identification of the first thiazolidinedione as an effective insulin sensitizer during the 1990s
In 1980, U.S. biotech company Genentech developed human insulin. The insulin is isolated from genetically altered bacteria (the bacteria contain the human gene for synthesizing human insulin), which produce large quantities of insulin. The purified insulin is distributed to pharmacies for use by diabetes patients.
Society and culture
The 1990 "St. Vincent Declaration was the result of international efforts to improve the care accorded to those with diabetes. Doing so is important both in terms of quality of life and life expectancy but also economically—expenses due to diabetes have been shown to be a major drain on health-and productivity-related resources for healthcare systems and governments.
Several countries established more and less successful national diabetes programmes to improve treatment of the disease.
A study shows that diabetic patients with neuropathic symptoms such as numbness or tingling in feet or hands are twice as likely to beunemployed as those without the symptoms.

OZONE LAYER

2010-11-07T11:32:00.000-08:00

Ozone layer

The ozone layer is a layer in Earth's atmosphere which contains relatively high concentrations of ozone (O₃). This layer absorbs 97–99% of the Sun's high frequency ultraviolet light, which is potentially damaging to life on Earth. It is mainly located in the lower portion of the stratosphere from approximately 13 km to 40 km above Earth, though the thickness varies seasonally and geographically. The ozone layer was discovered in 1913 by the French physicistsCharles Fabry and Henri Buisson. Its properties were explored in detail by the British meteorologist G. M. B. Dobson, who developed a simple spectrophotometer (the Dobsonmeter) that could be used to measure stratospheric ozone from the ground. Between 1928 and 1958 Dobson established a worldwide network of ozone monitoring stations which continues to operate today. The "Dobson unit", a convenient measure of the columnar density of ozone overhead, is named in his honor.

Origin of ozone

Ozone-oxygen cycle in the ozone layer.

The photochemical mechanisms that give rise to the ozone layer were discovered by the British physicist Sidney Chapman in 1930. Ozone in the Earth's stratosphere is created by ultraviolet light striking oxygen molecules containing two oxygen atoms (O₂), splitting them into individual oxygen atoms (atomic oxygen); the atomic oxygen then combines with unbroken O₂ to create ozone, O₃. The ozone molecule is also unstable (although, in the stratosphere, long-lived) and when ultraviolet light hits ozone it splits into a molecule of O₂ and an atom of atomic oxygen, a continuing process called the ozone-oxygen cycle, thus creating an ozone layer in the stratosphere, the region from about 10 to 50 km (32,000 to 164,000 feet) above Earth's surface. About 90% of the ozone in our atmosphere is contained in the stratosphere. Ozone concentrations are greatest between about 20 and 40 km, where they range from about 2 to 8 parts per million. If all of the ozone were compressed to the pressure of the air at sea level, it would be only a few millimeters thick

Ultraviolet light and ozone

Levels of ozone at various altitudes and blocking of ultraviolet radiation.

UV-B energy levels at several altitudes. Blue line shows DNA sensitivity. Red line shows surface energy level with 10% decrease in ozone

Although the concentration of the ozone in the ozone layer is very small, it is vitally important to life because it absorbs biologically harmful ultraviolet (UV) radiation coming from the Sun. UV radiation is divided into three categories, based on its wavelength; these are referred to as UV-A (400–315 nm), UV-B (315–280 nm), and UV-C (280–100 nm). UV-C, which would be very harmful to all living things, is entirely screened out by ozone at around 35 km altitude. UV-B radiation can be harmful to the skin and is the main cause of sunburn; excessive exposure can also cause genetic damage, resulting in problems such as skin cancer. The ozone layer is very effective at screening out UV-B; for radiation with a wavelength of 290 nm, the intensity at the top of the atmosphere is 350 million times stronger than at the Earth's surface. Nevertheless, some UV-B reaches the surface. Most UV-A reaches the surface; this radiation is significantly less harmful, although it can potentially cause genetic damage.

Distribution of ozone in the stratosphere

The thickness of the ozone layer—that is, the total amount of ozone in a column overhead—varies by a large factor worldwide, being in general smaller near the equator and larger towards the poles. It also varies with season, being in general thicker during the spring and thinner during the autumn in the northern hemisphere. The reasons for this latitude and seasonal dependence are complicated, involving atmospheric circulation patterns as well as solar intensity.

Since stratospheric ozone is produced by solar UV radiation, one might expect to find the highest ozone levels over the tropics and the lowest over Polar Regions. The same argument would lead one to expect the highest ozone levels in the summer and the lowest in the winter. The observed behavior is very different: most of the ozone is found in the mid-to-high latitudes of the northern and southern hemispheres, and the highest levels are found in the spring, not summer, and the lowest in the autumn, not winter in the northern hemisphere. During winter, the ozone layer actually increases in depth. This puzzle is explained by the prevailing stratospheric wind patterns, known as the Brewer-Dobson circulation. While most of the ozone is indeed created over the tropics, the stratospheric circulation then transports it pole ward and downward to the lower stratosphere of the high latitudes. However in the southern hemisphere, owing to the ozone hole phenomenon, the lowest amounts of column ozone found anywhere in the world are over the Antarctic in the southern spring period of September and October.

Brewer-Dobson circulation in the ozone layer.

The ozone layer is higher in altitude in the tropics, and lower in altitude in the extra tropics, especially in the Polar Regions. This altitude variation of ozone results from the slow circulation that lifts the ozone-poor air out of the troposphere into the stratosphere. As this air slowly rises in the tropics, ozone is produced by the overhead sun which photolyzes oxygen molecules. As this slow circulation bends towards the mid-latitudes, it carries the ozone-rich air from the tropical middle stratosphere to the mid-and-high latitudes lower stratosphere. The high ozone concentrations at high latitudes are due to the accumulation of ozone at lower altitudes.

The Brewer-Dobson circulation moves very slowly. The time needed to lift an air parcel from the tropical tropopause near 16 km (50,000 ft) to 20 km is about 4–5 months (about 30 feet (9.1 m) per day). Even though ozone in the lower tropical stratosphere is produced at a very slow rate, the lifting circulation is so slow that ozone can build up to relatively high levels by the time it reaches 26 km.

Ozone amounts over the continental United States (25°N to 49°N) are highest in the northern spring (April and May). These ozone amounts fall over the course of the summer to their lowest amounts in October, and then rise again over the course of the winter. Again, wind transport of ozone is principally responsible for the seasonal evolution of these higher latitude ozone patterns.

The total column amount of ozone generally increases as we move from the tropics to higher latitudes in both hemispheres. However, the overall column amounts are greater in the northern hemisphere high latitudes than in the southern hemisphere high latitudes. In addition, while the highest amounts of column ozone over the Arctic occur in the northern spring (March–April), the opposite is true over the Antarctic, where the lowest amounts of column ozone occur in the southern spring (September–October).

Ozone depletion

NASA projections of stratospheric ozone concentrations if chlorofluorocarbons had not been banned.

The ozone layer can be depleted by free radical catalysts, including nitric oxide (NO), nitrous oxide (N₂O), hydroxyl(OH), atomic chlorine (Cl), and atomic bromine (Br). While there are natural sources for all of these species, the concentrations of chlorine and bromine have increased markedly in recent years due to the release of large quantities of man-made organohalogen compounds, especially chlorofluorocarbons (CFCs) and bromofluorocarbons. These highly stable compounds are capable of surviving the rise to the stratosphere, where Cl and Br radicals are liberated by the action of ultraviolet light. Each radical is then free to initiate and catalyze a chain reaction capable of breaking down over 100,000 ozone molecules. The breakdown of ozone in the stratosphere results in the ozone molecules being unable to absorb ultraviolet radiation. Consequently, unabsorbed and dangerous ultraviolet-B radiation is able to reach the Earth’s surface. Ozone levels, over the northern hemisphere, have been dropping by 4% per decade. Over approximately 5% of the Earth's surface, around the north and south poles, much larger (but seasonal) declines have been seen; these are the ozone holes.

In 2009, nitrous oxide (N₂O) was the largest ozone-depleting substance emitted through human activities.

Regulation

In 1978, the United States, Canada and Norway enacted bans on CFC-containing aerosol sprays that are thought to damage the ozone layer. The European Community rejected an analogous proposal to do the same. In the U.S., chlorofluorocarbons continued to be used in other applications, such as refrigeration and industrial cleaning, until after the discovery of the Antarctic ozone hole in 1985. After negotiation of an international treaty (the Montreal Protocol), CFC production was sharply limited beginning in 1987 and phased out completely by 1996^.

On August 2, 2003, scientists announced that the depletion of the ozone layer may be slowing down due to the international ban on CFCs. Three satellites and three ground stations confirmed that the upper atmosphere ozone depletion rate has slowed down significantly during the past decade. The study was organized by the American Geophysical Union. Some breakdown can be expected to continue due to CFCs used by nations which have not banned them, and due to gases which are already in the stratosphere. CFCs have very long atmospheric lifetimes, ranging from 50 to over 100 years, so the final recovery of the ozone layer is expected to require several lifetimes.

Compounds containing C–H bonds have been designed to replace the function of CFC's (such as HCFC), since these compounds are more reactive and less likely to survive long enough in the atmosphere to reach the stratosphere where they could affect the ozone layer. While being less damaging than CFC's, HCFC's also have a significant negative impact on the ozone layer. HCFC's are also being phased out.

2010-11-05T10:28:00.000-07:00

SOLAR WIND

The solar wind is a stream of charged particles ejected from the upper atmosphere of the Sun. It mostly consists of electrons and protons with energies usually between 10 and 100 keV. The stream of particles varies in temperature and speed over time. These particles can escape the Sun’s gravity because of their high kinetic energy and the high temperature of the corona.

The solar wind creates the heliosphere, a vast bubble in the interstellar medium that surrounds the solar system. Other phenomena include geomagnetic that can knock out power grids on Earth, the aurorae (northern and southern lights), and the plasma tails of comets that always point away from the Sun.

HISTORY

The continuous stream of particles flowing outward from the Sun was first suggested by British astronomer Richard C. Carrington. In 1859, Carrington and Richard Hodgson independently made the first observation of what would later be called a solar flare. This is a sudden outburst of energy from the Sun's atmosphere. On the following day, a geomagnetic storm was observed, and Carrington suspected that there may be a connection. George Fitzgerald later suggested that matter was being regularly accelerated away from the Sun and was reaching the Earth after several days.

Laboratory simulation of the magnetosphere's influence on the Solar Wind; these auroral-likeBirkeland currents were created in a terrella, a magnetised anode globe in an evacuated chamber.

The ideas of Fitzgerald and others were further developed by the Norwegian physicist Kristian Birkeland. His geomagnetic surveys showed that auroral activity was nearly uninterrupted. As these displays and other geomagnetic activity were being produced by particles from the Sun, he concluded that the Earth was being continually bombarded by "rays of electric corpuscles emitted by the Sun". In 1916, Birkeland was probably the first person to successfully predict that, "From a physical point of view it is most probable that solar rays are neither exclusively negative nor positive rays, but of both kinds". In other words, the solar wind consists of both negative electrons and positive ions. Three years later in 1919, Frederick Lindemann also suggested that particles of polarities, protons as well as electrons, come from the Sun.

Around the 1930s, scientists had determined that the temperature of the solar corona must be a million degrees Celsius because of the way it stood out into space (as seen during total eclipses). Later spectroscopic work confirmed this extraordinary temperature. In the mid-1950s the British mathematician Sydney Chapman calculated the properties of a gas at such a temperature and determined it was such a superb conductor of heat that it must extend way out into space, beyond the orbit of Earth. Also in the 1950s, a German scientist named Ludwig Biermann became interested in the fact that no matter whether a comet is headed towards or away from the Sun, its tail always points away from the Sun. Biermann postulated that this happens because the Sun emits a steady stream of particles that pushes the comet's tail away. Wilfried Schröder claims in his book, Who First Discovered the Solar Wind?, that the German astronomer Paul Ahnert was the first to relate solar wind to comet tail direction based on observations of the comet Whipple-Fedke (1942g).

Eugene Parker realized that the heat flowing from the Sun in Chapman's model and the comet tail blowing away from the Sun in Biermann's hypothesis had to be the result of the same phenomenon, which he termed the "solar wind". Parker showed that even though the Sun's corona is strongly attracted by solar gravity, it is such a good conductor of heat that it is still very hot at large distances. Since gravity weakens as distance from the Sun increases, the outer coronal atmosphere escapes supersonically into interstellar space. Furthermore, Parker was the first person to notice that the weakening effect of the gravity has the same effect on hydrodynamic flow as a de Laval nozzle: it incites a transition from subsonic to supersonic flow.

Opposition to Parker's hypothesis on the solar wind was strong. The paper he submitted to the Astrophysical Journal in 1958 was rejected by two reviewers. It was saved by the editor Subrahmanyan Chandrasekhar (who later received the 1983 Nobel Prize in physics).

In January 1959, the Soviet satellite Luna 1 first directly observed the solar wind and measured its strength. They were detected by hemispherical ion traps. The discovery, made by Konstantin Gringauz, was verified by Luna 2, Luna 3 and by the more distant measurements of Venera 1. Three years later its measurement was performed by Americans (Neugebauer and collaborators) using the Mariner 2spacecraft.

However, the acceleration of the fast wind is still not understood and cannot be fully explained by Parker's theory. The first numerical simulation of the solar wind in the solar corona including closed and open field lines was performed by Pneuman and Knopp in 1971. Themagnetohydrodynamics equations in steady state were solved iteratively starting with an initial dipolar configuration.

In the late 1990s the Ultraviolet Coronal Spectrometer (UVCS) instrument on board the SOHO spacecraft observed the acceleration region of the fast solar wind emanating from the poles of the Sun, and found that the wind accelerates much faster than can be accounted for by thermodynamic expansion alone. Parker's model predicted that the wind should make the transition to supersonic flow at an altitude of about 4 solar radii from the photosphere; but the transition (or "sonic point") now appears to be much lower, perhaps only 1 solar radius above the photosphere

suggesting that some additional mechanism accelerates the solar wind away from the Sun.

In 1990, the Ulysses probe was launched to study the solar wind from high solar latitudes. All prior observations had been made at or near the solar system's ecliptic plane.

EMISSION

While early models of the solar wind used primarily thermal energy to accelerate the material, by the 1960s it was clear that thermal acceleration alone cannot account for the high speed of solar wind. An additional unknown acceleration mechanism is required, and likely relates to magnetic fields in the solar atmosphere.

The Sun's corona, or extended outer layer, is a region of plasma that is heated to over a million degrees Celsius. As a result of thermal collisions, the particles within the inner corona have a range and distribution of speeds described by a Maxwellian distribution. The mean velocity of these particles is about 145 km/s, which is well below the solar escape velocity of 618 km/s. However, a few of the particles achieve energies sufficient to reach the terminal velocity of 400 km/s, which allows them to feed the solar wind. At the same temperature, electrons, due to their much smaller mass, reach escape velocity and build up an electric field that further accelerates ions - charged atoms - away from the Sun.

The total number of particles carried away from the Sun by the solar wind is about 1.3 × 10³⁶ per second. Thus, the total mass loss each year is about (2–3) × 10⁻¹⁴ solar masses, or 6.7 billion tons per hour. This is equivalent to losing a mass equal to the Earth every 150 million years. However, only about 0.01% of the Sun's total mass has been lost through the solar wind. Other stars have much stronger stellar winds that result in significantly higher mass loss rates.

Components

The solar wind is divided into two components, respectively termed the slow solar wind and the fast solar wind. The slow solar wind has a velocity of about 400 km/s, a temperature of 1.4–1.6 × 10⁶ K and a composition that is a close match to the corona. By contrast, the fast solar wind has a typical velocity of 750 km/s, a temperature of 8 × 10⁵ K and it nearly matches the composition of the Sun's photosphere. The slow solar wind is twice as dense and more variable in intensity than the fast solar wind. The slow wind also has a more complex structure, with turbulent regions and large-scale structures.

The slow solar wind appears to originate from a region around the Sun's equatorial belt that is known as the "streamer belt". Coronal streamers extend outward from this region, carrying plasma from the interior along closed magnetic loops. Observations of the Sun between 1996 and 2001 showed that emission of the slow solar wind occurred between latitudes of 30–35° around the equator during the solar (the period of lowest solar activity), then expanded toward the poles as the minimum waned. By the time of the solar maximum, the poles were also emitting a slow solar wind.

The fast solar wind is thought to originate from coronal holes, which are funnel-like regions of open field lines in the Sun's magnetic field. Such open lines are particularly prevalent around the Sun's magnetic poles. The plasma source is small magnetic fields created by convection in the solar atmosphere. These fields confine the plasma and transport it into the narrow necks of the coronal funnels, which are located only 20,000 kilometers above the photosphere. The plasma is released into the funnel when these magnetic field lines reconnect.

Coronal mass ejection

Both the fast and slow solar wind can be interrupted by large, fast-moving bursts of plasma called interplanetary coronal mass ejections, or ICMEs. ICMEs are the interplanetary manifestation of solar coronal mass ejections, which are caused by release of magnetic energy at the Sun. CMEs are often called "solar storms" or "space storms" in the popular media. They are sometimes, but not always, associated with solar flares, which are another manifestation of magnetic energy release at the Sun. ICMEs cause shock waves in the thin plasma of the heliosphere, launching electromagnetic waves and accelerating particles (mostly protons and electrons) to form showers of radiation that precede the CME.

When an CME impacts the Earth's magnetosphere, it temporarily deforms the Earth's magnetic field, changing the direction of compass needles and inducing large electrical ground currents in Earth itself; this is called a geomagnetic storm and it is a global phenomenon. CME impacts can induce magnetic reconnection in Earth's magneto tail (the midnight side of the magnetosphere); this launches protons and electrons downward toward Earth's atmosphere, where they form the aurora.

ICMEs are not the only cause of space weather. Different patches on the Sun are known to give rise to slightly different speeds and densities of wind depending on local conditions. In isolation, each of these different wind streams would form a spiral with a slightly different angle, with fast-moving streams moving out more directly and slow-moving streams wrapping more around the Sun. Faster-moving streams tend to overtake slower streams that originate westward of them on the sun, forming turbulent co-rotating interaction regions that give rise to wave motions and accelerated particles, and that affect Earth's magnetosphere in the same way as, but more gently than, CMEs.

EFFECTS ON THE SOLAR SYSTEM

Over the lifetime of the Sun, the surface rotation rate has decreased significantly. This loss of rotation is thought to have been caused by interaction of the Sun's surface layers with the escaping solar wind. The wind is considered responsible for the tails of comets, along with the Sun's radiation. The solar wind contributes to fluctuations in celestial radio waves observed on the Earth, through an effect called interplanetary scintillation.

Magnetospheres

As the solar wind approaches a planet that has a well-developed magnetic field (such as Earth, Jupiter and Saturn), the particles are deflected by the Lorentz force. This region, known as the magnetosphere, causes the particles to travel around the planet rather than bombarding the atmosphere or surface. The magnetosphere is roughly shaped like a hemisphere on the side facing the Sun, then is drawn out in a long wake on the opposite side. The boundary of this region is called the magnetopause, and some of the particles are able to penetrate the magnetosphere through this region by partial reconnection of the magnetic field lines.

Earth itself is largely protected from the solar wind by its magnetic field, which deflects most of the charged particles, however some of the charged particles are trapped in the Van Allen radiation belt. A smaller number of particles from the solar wind manage to travel, as though on an electromagnetic energy transmission line, to the Earth's upper atmosphere and ionosphere in the auroral zones. The only time the solar wind is observable on the Earth is when it is strong enough to produce phenomena such as the aurora and geomagnetic storms. Bright auroras strongly heat the ionosphere, causing its plasma to expand into the magnetosphere, increasing the size of the plasma geosphere, and causing escape of atmospheric matter into the solar wind. Geomagnetic storms result when the pressure of plasmas contained inside the magnetosphere is sufficiently large to inflate and thereby distort the geomagnetic field.

The solar wind is responsible for the overall shape of Earth's magnetosphere, and fluctuations in its speed, density, direction, and entrained magnetic field strongly affect Earth's local space environment. For example, the levels of ionizing radiation and radio interference can vary by factors of hundreds to thousands; and the shape and location of the magnetopause and bow shock wave upstream of it can change by several Earth radii, exposing geosynchronous satellites to the direct solar wind. These phenomena are collectively called space weather.

Atmospheres

The solar wind affects the other incoming cosmic rays interacting with the atmosphere of planets. Moreover, planets with a weak or non-existent magnetosphere are subject to atmospheric stripping by the solar wind.

Venus, the nearest and most similar planet to Earth in our solar system, has an atmosphere 100 times denser than our own. Modern space probes have discovered a comet-like tail that extends to the orbit of the Earth.

Mars is larger than Mercury and four times farther from the Sun, and yet even here it is thought that the solar wind has stripped away up to a third of its original atmosphere, leaving a layer 1/100th as dense as the Earth's. It is believed the mechanism for this atmospheric stripping is gas being caught in bubbles of magnetic field, which are ripped off by solar winds.

Planetary surfaces

Mercury, the nearest planet to the Sun, bears the full brunt of the solar wind, and its atmosphere is vestigial and transient, its surface bathed in radiation.

The Earth's Moon has no atmosphere or intrinsic magnetic field, and consequently its surface is bombarded with the full solar wind. The Project Apollo missions deployed passive aluminum collectors in an attempt to sample the solar wind, and lunar soil returned for study confirmed that the lunar regolith is enriched in atomic nuclei deposited from the solar wind. There has been speculation that these elements may prove to be useful resources for future lunar colonies.

OUTER LIMITS

The solar wind "blows a bubble" in the interstellar medium (the rarefied hydrogen and helium gas that permeates the galaxy). The point where the solar wind's strength is no longer great enough to push back the interstellar medium is known as the heliopause, and is often considered to be the outer "border" of the solar system. The distance to the heliopause is not precisely known, and probably varies widely depending on the current velocity of the solar wind and the local density of the interstellar medium, but it is known to lie far outside the orbit of Pluto. Scientists hope to gain more perspective on the heliopause from data acquired through the Interstellar Boundary Explorer (IBEX) mission, launched in October 2008.

NOBEL EVENTS

§ From May 10, 1999 to May 12, NASA's ACE and Wind spacecraft observed a 98% decrease of solar wind density. This allowed energetic electrons from the Sun to flow to Earth in narrow beams known as "strahl", which caused a highly unusual "polar rain" event, in which a visible aurora appeared over the North Pole. In addition, Earth's magnetosphere increased to between 5 and 6 times its normal size.

VEHICLES WITHOUT DRIVERS

2010-10-29T08:34:00.000-07:00

What Is HAARP?

2010-09-29T10:36:00.000-07:00

What Is HAARP?

The official HAARP facility is located in Gakuna, Alaska. The site consists of a collection of antennae, arranged in a computer-controlled grid, known as a "phased array." A phased array has the ability to focus radio signals in a precise direction, without the necessity of turning the antennae. Modern radar systems no longer use the revolving dish that we have come to recognize. The new radar antennae, which rely on phased arrays, look more like the flat screen of a drive-in movie, speckled with small umbrella-like antennae in neat rows. The phased array in HAARP is not a radar, but it uses some of the same extremely high frequencies to focus a powerful radio beam to specific locations in the Earth's ionosphere.

The ionosphere is a layer of charged particles (or "ions") located about 60-90 kilometers above the Earth's surface. It is the layer which reflects short wave radio waves and makes it possible for a transmitter in New York to send a signal to Tokyo. Short waves may be good enough to send The Voice of America broadcasts, but they are subject to noise and static. Short wave signals lose much of their power as they travel and can even be blocked by the weather and sunspot activity.

Extremely High Frequency waves, on the other hand, aremuch shorter than short waves. They travel in compact, narrowly focused, beams. They do not encounter static or deteriorate from rain or clouds. Since they retain their strength over long distances, they are preferred for most point-to-point communications. Unfortunately, though, EHF waves (including microwaves) do not naturally reflect and bounce off of the ionosphere. For this reason, high frequency waves are said to propagate along the "line of sight." If you own a satellite television dish, you know that it is important for your antenna to be pointed in the direction of the satellite. This is because you are receiving extremely high frequency waves.

Eastlund's discovery involved beaming High Frequency (HF) and Extremely High Frequency (EHF) waves, of extremely high power (over a billion watts), directly at a point on the ionosphere. When this was done, the ionosphere became heated from the accumulating electrical energy. You might think of it as "cooking" the atmosphere.

The heated portion of the ionosphere expands like heated plastic and is raised to a higher altitude, causing an atmospheric "bulge." Eastlund discovered that this bulge was highly reflective to radio waves, and, because of its altitude, it could bounce high frequency radio signals to points well beyond the horizon. Even efficient ELF and microwaves signals, which normally would pass through the ionosphere into space, could be deflected without much loss of strength. He called this heated "bulge" the "lens effect."

Eastlund's first patent (US #4,686,605) was for a "method and apparatus for altering a region in the Earth's atmosphere, ionosphere, and or magnetosphere." His second patent described the reflection of a second signal, using the ionospheric bulge, to distant locations on the Earth's surface. Eastlund had been working with the Atlantic Richfield Company, holders of a massive reserve of natural gas under Alaska's north slope. ARCO bought Eastlund's first two patents with the understanding that this new technology would make it possible for their natural gas reserves, too expensive to be piped from Alaska, to be converted to electrical energy on the north slope, and then bounced off the heated ionosphere to customers in remote locations around the globe. Also, because Eastlund's "heaters" could elevate the Earth's ionosphere, his discovery provided the ability to control weather! Jet streams could be altered, tornadoes could be zapped and rain could be made-- anywhere and anytime-- right here and right now! But the military had other plans.

Eastlund's patents were sealed under a US Secrecy Order. The military realized that his first patent outlined the recipe for an over-the-horizon radar apparatus, capable of detecting Soviet launched ICBM's within seconds of their launch. His second patent was even more appetizing. President Ronald Regan's infamous Star Wars program had challenged the military with tall order. Their complex laser systems, nuke satellites and rail-guns didn't work. The military were years from meeting Pentagon goals. Now, unexpectedly, their prayers had been answered. Eastlund's "energy transmission system" would be turned into the ultimate "death ray."

HAARP: The Weapon (continued)

Wave length: explained

When we speak of "short" waves or "extremely short" waves, we are speaking about the distance that a radio signal must travel to produce one complete (often called "sign wave") positive and negative cycle. Electrons travel at the speed of light, a constant velocity in the universe, estimated to be 300,000,000 meters per second. The frequency of a radio signal is the number of complete "positive-negative" cycles that occur in a second (called "hertz"). A frequency of 15,000,000 (or 15 million hertz) means that the electrical energy is changing from positive to negative at the rate of 15-million times a second.

To determine the "length" of this frequency, or "wavelength," we simply divide the velocity of light, 300,000,000 meters per second, by the frequency, say 15,000,000 cycles per second, to arrive at a distance in meters. Thus, 15 MHz would equal 20 meters.

The length of a radio antenna is determined by the frequency that it is designed to transmit or receive. In the case above (15 MHz), the ideal length of a long wire antenna would be 20 meters. However, this is not always practical. Engineers have found that they can successfully divide the length in half, or in a quarter of the full wavelength, and still maintain both transmission and reception of the prescribed signal frequency.

If one uses this formula to determine the wavelength of ELF signals, which range from 30 to 3000 hertz, one can easily see why extremely long antennae are needed, as pictured in Viewzone's Unusual Photograph of January 1999, even if a quarter wavelength is used.

INOSPHERE

2010-09-27T09:13:00.000-07:00

Ionosphere

The ionosphere is a portion of the upper atmosphere, between the thermosphere and the exosphere, distinguished because it isionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth.

GEOPHYSICS

The ionosphere is a shell of electrons and electrically charged atoms and molecules that surrounds the Earth, stretching from a height of about 50 km to more than 1000 km. It owes its existence primarily to ultraviolet radiation from the sun.

The lowest part of the Earth's atmosphere, the troposphere extends from the surface to about 10 km (6 miles). Above 10 km is thestratosphere, followed by the mesosphere. In the stratosphere incoming solar radiation creates the ozone layer. At heights of above 80 km (50 miles), in the thermosphere, the atmosphere is so thin that free electrons can exist for short periods of time before they are captured by a nearby positive ion. The number of these free electrons is sufficient to affect radio propagation. This portion of the atmosphere is ionized and contains a plasma which is referred to as the ionosphere. In a plasma, the negative free electrons and the positive ions are attracted to each other by the electromagnetic force, but they are too energetic to stay fixed together in an electrically neutral molecule.

Ultraviolet (UV), X-Ray and shorter wavelengths of solar radiation are ionizing, since photons at these frequencies contain sufficient energy to dislodge an electron from a neutral gas atom or molecule upon absorption. In this process the light electron obtains a high velocity so that the temperature of the created electronic gas is much higher (of the order of thousand K) than the one of ions and neutrals. The reverse process to Ionization is recombination, in which a free electron is "captured" by a positive ion, occurs spontaneously. This causes the emission of a photon carrying away the energy produced upon recombination. As gas density increases at lower altitudes, the recombination process prevails, since the gas molecules and ions are closer together. The balance between these two processes determines the quantity of ionization present.

Ionization depends primarily on the Sun and its activity. The amount of ionization in the ionosphere varies greatly with the amount of radiation received from the sun. Thus there is a diurnal (time of day) effect and a seasonal effect. The local winter hemisphere is tipped away from the Sun, thus there is less received solar radiation. The activity of the sun is associated with the sunspot cycle, with more radiation occurring with more sunspots. Radiation received also varies with geographical location (polar, auroral zones, mid-latitudes, and equatorial regions). There are also mechanisms that disturb the ionosphere and decrease the ionization. There are disturbances such as solar flares and the associated release of charged particles into the solar wind which reaches the Earth and interacts with itsgeomagnetic field.

The ionospheric layers

At night the F layer is the only layer of significant ionization present, while the ionization in the E and D layers is extremely low. During the day, the D and E layers become much more heavily ionized, as does the F layer, which develops an additional, weaker region of ionisation known as the F₁ layer. The F₂ layer persists by day and night and is the region mainly responsible for the refraction of radio waves.

D layer

The D layer is the innermost layer, 60 km to 90 km above the surface of the Earth. Ionization here is due to Lyman series-alpha hydrogen radiation at a wavelength of 121.5 nanometre (nm) ionizing nitric oxide (NO). In addition, with high Solar activityhard X-rays (wavelength <>2, O₂). During the night cosmic raysproduce a residual amount of ionization. Recombination is high in the D layer, the net ionization effect is low, but loss of wave energy is great due to frequent collisions of the electrons (about ten collisions every msec). As a result high-frequency (HF) radio waves are not reflected by the D layer but suffer loss of energy therein. This is the main reason for absorption of HF radio waves, particularly at 10 MHz and below, with progressively smaller absorption as the frequency gets higher. The absorption is small at night and greatest about midday. The layer reduces greatly after sunset; a small part remains due to galactic cosmic rays. A common example of the D layer in action is the disappearance of distant AM broadcast band stations in the daytime.

During solar proton events, ionization can reach unusually high levels in the D-region over high and polar latitudes. Such very rare events are known as Polar Cap Absorption (or PCA) events, because the increased ionization significantly enhances the absorption of radio signals passing through the region. In fact, absorption levels can increase by many tens of dB during intense events, which is enough to absorb most (if not all) transpolar HF radio signal transmissions. Such events typically last less than 24 to 48 hours.

E layer

The E layer is the middle layer, 90 km to 120 km above the surface of the Earth. Ionization is due to soft X-ray (1-10 nm) and far ultraviolet (UV) solar radiation ionization of molecular oxygen (O₂). Normally, at oblique incidence, this layer can only reflect radio waves having frequencies lower than about 10 MHz and may contribute a bit to absorption on frequencies above. However during intense Sporadic E events the E_s layer can reflect frequencies up to 50 MHz and higher.The vertical structure of the E layer is primarily determined by the competing effects of ionization and recombination. At night the E layer rapidly disappears because the primary source of ionization is no longer present. After sunset an increase in the height of the E layer maximum increases the range to which radio waves can travel by reflection from the layer.

This region is also known as the Kennelly-Heaviside Layer or simply the Heaviside layer. Its existence was predicted in 1902 independently and almost simultaneously by the American electrical engineer Arthur Edwin Kennelly (1861-1939) and the British physicist Oliver Heaviside (1850-1925). However, it was not until 1924 that its existence was detected by Edward V. Appleton.

E_s

The E_s layer (sporadic E-layer) is characterized by small, thin clouds of intense ionization, which can support reflection of radio waves, rarely up to 225 MHz. Sporadic-E events may last for just a few minutes to several hours. Sporadic E propagation makes radio amateurs very excited, as propagation paths that are generally unreachable can open up. There are multiple causes of sporadic-E that are still being pursued by researchers. This propagation occurs most frequently during the summer months when high signal levels may be reached. The skip distances are generally around 1000 km (620 miles). VHF TV and FM broadcast DX'ers also get excited as their signals can be bounced back to Earth by Es. Distances for one hop propagation can be as close as 900 km [500 miles] or up to 2500 km (1,400 miles). Douple-hop reception over 3500 km (2,000 miles) is possible, too.

F layer

The F layer or region, also known as the Appleton layer extends from about 200 km to more than 500 km above the surface of Earth. It is the densest point of the ionosphere, which implies signals penetrating this layer will escape into space. Beyond this layer is thetopside ionosphere. Here extreme ultraviolet (UV, 10–100 nm) solar radiation ionizes atomic oxygen. The F layer consists of one layer at night, but during the day, a deformation often forms in the profile that is labeled F₁. The F₂ layer remains by day and night responsible for most skywave propagation of radio waves, facilitating high frequency (HF, or shortwave) radio communications over long distances.

From 1972 to 1975 NASA launched the AEROS and AEROS B satellites to study the F region.

Ionospheric model

An ionospheric model is a mathematical description of the ionosphere as a function of location, altitude, day of year, phase of the sun spot cycle and geomagnetic activity. Geophysically, the state of the ionospheric plasma may be described by four parameters:electron density, electron and ion temperature and, since several species of ions are present, ionic composition. Radio propagationdepends uniquely on electron density.

Models are usually expressed as computer programs. The model may be based on basic physics of the interactions of the ions and electrons with the neutral atmosphere and sun light, or it may be a statistical description based on a large number of observations or a combination of physics and observations. One of the most widely used models is the International Reference Ionosphere (IRI) (IRI 2007), which is based on data and specifies the four parameters just mentionned. The IRI is an international project sponsored by theCommittee on Space Research (COSPAR) and the International Union of Radio Science (URSI). The major data sources are the worldwide network of ionosondes, the powerful incoherent scatter radars (Jicamarca, Arecibo, Millstone Hill, Malvern, St. Santin), the ISIS and Alouette topside sounders, and in situ instruments on several satellites and rockets. IRI is updated yearly. IRI will be established in 2009 by the International Organization for Standardization (ISO) as standard TS16457. IRI is accurate in describing the variation of the electron density from bottom of the ionosphere to the altitude of maximum density than in describing the total electron content (TEC).

Anomalies to the ideal model

Ionograms allow deducing not only the shape of the different layers but also the structure of the electron/ion-plasma. Rough traces, indicating nonhomogeneity, are seen predominantly at night and at higher latitudes, and during disturbed conditions.

Winter anomaly

At mid-latitudes, the F₂ layer daytime ion production is higher in the summer, as expected, since the sun shines more directly on the earth. However, there are seasonal changes in the molecular-to-atomic ratio of the neutral atmosphere that cause the summer ion loss rate to be even higher. The result is that the increase in the summertime loss overwhelms the increase in summertime production, and total F₂ ionization is actually lower in the local summer months. This effect is known as the winter anomaly. The anomaly is always present in the northern hemisphere, but is usually absent in the southern hemisphere during periods of low solar activity.

Equatorial anomaly

Within approximately ± 20 degrees of the magnetic equator, is the equatorialanomaly. It is the occurrence of a trough of concentrated ionization in the F₂ layer. The Earth's magnetic field lines are horizontal at the magnetic equator. Solar heating and tidal oscillations in the lower ionosphere move plasma up and across the magnetic field lines. This sets up a sheet of electric current in the E region which, with the horizontal magnetic field, forces ionization up into the F layer, concentrating at ± 20 degrees from the magnetic equator. This phenomenon is known as theequatorial fountain.

Equatorial electrojet

The worldwide solar-driven wind results in the so-called Sq (solar quiet) current system in the E region of the Earth's ionosphere (100–130 km altitude). Resulting from this current is an electrostatic field directed E-W (dawn-dusk) in the equatorial day side of the ionosphere. At the magnetic dip equator, where the geomagnetic field is horizontal, this electric field results in an enhanced eastward current flow within ± 3 degrees of the magnetic equator, known as the equatorial electrojet.

Ionospheric perturbations

X-rays: sudden ionospheric disturbances (SID)

When the sun is active, strong solar flares can occur that will hit the Earth with hard X-rays on the sunlit side of the Earth. They will penetrate to the D-region, release electrons which will rapidly increase absorption causing a High Frequency (3-30 MHz) radio blackout. During this time Very Low Frequency (3 – 30 kHz) signals will become reflected by the D layer instead of the E layer, where the increased atmospheric density will usually increase the absorption of the wave, and thus dampen it. As soon as the X-rays end, thesudden ionospheric disturbance (SID) or radio black-out ends as the electrons in the D-region recombine rapidly and signal strengths return to normal.

Protons: polar cap absorption (PCA)

Associated with solar flares is a release of high-energy protons. These particles can hit the Earth within 15 minutes to 2 hours of the solar flare. The protons spiral around and down the magnetic field lines of the Earth and penetrate into the atmosphere near the magnetic poles increasing the ionization of the D and E layers. PCA's typically last anywhere from about an hour to several days, with an average of around 24 to 36 hours.

Geomagnetic storms

A geomagnetic storm is a temporary intense disturbance of the Earth's magnetosphere.

§ During a geomagnetic storm the F₂ layer will become unstable, fragment, and may even disappear completely.

§ In the Northern and Southern pole regions of the Earth aurora will be observable in the sky.

Lightning

Lightning can cause ionospheric perturbations in the D-region in one of two ways. The first is through VLF frequency radio waves launched into the magnetosphere. These so-called "whistler" mode waves can interact with radiation belt particles and cause them to precipitate onto the ionosphere, adding ionization to the D-region. These disturbances are called Lightning-induced Electron Precipitation (LEP) events.

Additional ionization can also occur from direct heating/ionization as a result of huge motions of charge in lightning strikes. These events are called Early/Fast.

In 1925, C. F. Wilson proposed a mechanism by which electrical discharge from lightning storms could propagate upwards from clouds to the ionosphere. Around the same time, Robert Watson-Watt, working at the Radio Research Station in Slough, UK, suggested that the ionospheric sporadic E layer (Es) appeared to be enhanced as a result of lightning but that more work was needed. In 2005, C. Davis and C. Johnson, working at the Rutherford Appleton Laboratory in Oxfordshire, UK, demonstrated that the Es layer was indeed enhanced as a result of lightning activity. Their subsequent research has focussed on the mechanism by which this process can occur.

Radio application

DX communication, popular among amateur radio enthusiasts, is a term given to communication over great distances. Thanks to the property of ionized atmospheric gases to refract high frequency (HF, or shortwave) radio waves, the ionosphere can be utilized to "bounce" a transmitted signal down to ground. Transcontinental HF-connections rely on up to 5 bounces, or hops. Such communications played an important role during World War II. Karl Rawer's most sophisticated prediction method took account of several (zig-zag) paths, attenuation in the D-region and predicted the 11-years solar cycle by a method due to Wolfgang Gleißberg.

Mechanism of refraction

When a radio wave reaches the ionosphere, the electric field in the wave forces the electrons in the ionosphere into oscillation at the same frequency as the radio wave. Some of the radio-frequency energy is given up to this resonant oscillation. The oscillating electrons will then either be lost to recombination or will re-radiate the original wave energy. Total refraction can occur when the collision frequency of the ionosphere is less than the radio frequency, and if the electron density in the ionosphere is great enough.

The critical frequency is the limiting frequency at or below which a radio wave is reflected by an ionospheric layer at vertical incidence. If the transmitted frequency is higher than the plasma frequency of the ionosphere, then the electrons cannot respond fast enough, and they are not able to re-radiate the signal. It is calculated as shown below:

where N = electron density per cm³ and f_critical is in MHz.

The Maximum Usable Frequency (MUF) is defined as the upper frequency limit that can be used for transmission between two points at a specified time.

where $α$ = angle of attack, the angle of the wave relative to the horizon, and sin is the sine function.

The cutoff frequency is the frequency below which a radio wave fails to penetrate a layer of the ionosphere at the incidence angle required for transmission between two specified points by refraction from the layer.

Other applications

The open system electrodynamic tether, which uses the ionosphere, is being researched. The space tether uses plasma contactors and the ionosphere as parts of a circuit to extract energy from the Earth's magnetic field by electromagnetic induction.

Measurements

Ionograms

Ionograms show the virtual heights and critical frequencies of the ionospheric layers and which are measured by an ionosonde. An ionosonde sweeps a range of frequencies, usually from 0.1 to 30 MHz, transmitting at vertical incidence to the ionosphere. As the frequency increases, each wave is refracted less by the ionization in the layer, and so each penetrates further before it is reflected. Eventually, a frequency is reached that enables the wave to penetrate the layer without being reflected. For ordinary mode waves, this occurs when the transmitted frequency just exceeds the peak plasma, or critical, frequency of the layer. Tracings of the reflected high frequency radio pulses are known as ionograms. Reduction rules are given in:"URSI Handbook of Ionogram Interpretation and Reduction", edited by W.R.Piggott and Karl Rawer, Elsevier Amsterdam 1961. Translations in Chinese, French, Japanese, Russian were edited by national organisations.

Incoherent scatter radars

Incoherent scatter radars operate above the critical frequencies. Therefore the technique allows to probe the ionosphere, unlike ionosondes, also above the electron density peaks. The thermal fluctuations of the electron density scattering the transmitted signals lack coherence, which gave the technique its name. Their power spectrum contains information not only on the density, but also on the ion and electron temperatures, ion masses and drift velocities.

Solar flux

Solar flux is a measurement of the intensity of solar radio emissions at a frequency of 2800 MHz made using a radio telescope located in Dominion Radio Astrophysical Observatory, Penticton, British Columbia, Canada. Known also as the 10.7 cm flux (the wavelength of the radio signals at 2800 MHz), this solar radio emission has been shown to be proportional to sunspot activity. However, the level of the sun's ultraviolet and X-ray emissions is primarily responsible for causing ionization in the Earth's upper atmosphere. We now have data from the GOES spacecraft that measures the background X-ray flux from the sun, a parameter more closely related to the ionization levels in the ionosphere.

§ The A and K indices are a measurement of the behavior of the horizontal component of the geomagnetic field. The K index uses a scale from 0 to 9 to measure the change in the horizontal component of the geomagnetic field. A new K index is determined at theTable Mountain Observatory, north of Boulder, Colorado.

§ The geomagnetic activity levels of the earth are measured by the fluctuation of the Earth's magnetic field in SI units called teslas (or in non-SI gauss, especially in older literature). The Earth's magnetic field is measured around the planet by many observatories. The data retrieved is processed and turned into measurement indices. Daily measurements for the entire planet are made available through an estimate of the ap index, called the planetary A-index (PAI).

Scientific research on ionospheric propagation

Scientists also are exploring the structure of the ionosphere by a wide variety of methods, including passive observations of optical and radio emissions generated in the ionosphere, bouncing radio waves of different frequencies from it, incoherent scatter radars such as the EISCAT, Sondre Stromfjord, Millstone Hill, Arecibo, and Jicamarca radars, coherent scatter radars such as the Super Dual Auroral Radar Network (SuperDARN) radars, and using special receivers to detect how the reflected waves have changed from the transmitted waves.

A variety of experiments, such as HAARP (High Frequency Active Auroral Research Program), involve high power radio transmitters to modify the properties of the ionosphere. These investigations focus on studying the properties and behavior of ionospheric plasma, with particular emphasis on being able to understand and use it to enhance communications and surveillance systems for both civilian and military purposes. HAARP was started in 1993 as a proposed twenty year experiment, and is currently active near Gakona, Alaska.

The SuperDARN radar project researches the high- and mid-latitudes using coherent backscatter of radio waves in the 8 to 20 MHz range. Coherent backscatter is similar to Bragg scattering in crystals and involves the constructive interference of scattering from ionospheric density irregularities. The project involves more than 11 different countries and multiple radars in both hemispheres.

Scientists are also examining the ionosphere by the changes to radio waves from satellites and stars passing through it. The Arecibo radio telescope located in Puerto Rico, was originally intended to study Earth's ionosphere.

Ionospheres on other planets and Titan

The atmosphere of Titan, the only moon known to have one, includes an ionosphere. It ranges from about 1100 to 1300 km in altitude, and contains carbon compounds.

Planets with ionospheres (incomplete list):

Ionosphere of Venus

Ionosphere of Uranus

History

In 1899, Nikola Tesla moved from New York to Colorado Springs, Colorado, where he would have room for his high-voltage, high-frequency experiments. Upon his arrival he told reporters that he was conducting wireless telegraphy experiments transmitting signals from Pikes Peak to Paris. Tesla's diary contains explanations of his experiments concerning the ionosphere.

Guglielmo Marconi received the first trans-Atlantic radio signal on December 12, 1901, in St. John's, Newfoundland (now in Canada) using a 152.4 m (500 ft) kite-supported antenna for reception. The transmitting station in Poldhu, Cornwall used a spark-gap transmitter to produce a signal with a frequency of approximately 500 kHz and a power of 100 times more than any radio signal previously produced. The message received was three dits, the Morse code for the letter S. To reach Newfoundland the signal would have to bounce off the ionosphere twice. Dr. Jack Belrose has recently contested this, however, based on theoretical and experimental work. However, Marconi did achieve transatlantic wireless communications beyond a shadow of doubt in Glace Bay one year later.

In 1902, Oliver Heaviside proposed the existence of the Kennelly-Heaviside Layer of the ionosphere which bears his name. Heaviside's proposal included means by which radio signals are transmitted around the Earth's curvature. Heaviside's proposal, coupled with Planck's law of black body radiation, may have hampered the growth of radio astronomy for the detection of electromagnetic waves from celestial bodies until 1932 (and the development of high frequency radio transceivers). Also in 1902, Arthur Edwin Kennellydiscovered some of the ionosphere's radio-electrical properties.

In 1912, the U.S. Congress imposed the Radio Act of 1912 on amateur radio operators, limiting their operations to frequencies above 1.5 MHz (wavelength 200 meters or smaller). The government thought those frequencies were useless. This led to the discovery of HF radio propagation via the ionosphere in 1923.

In 1926, Scottish physicist Robert Watson-Watt introduced the term ionosphere in a letter published only in 1969 in Nature:

We have in quite recent years seen the universal adoption of the term ‘stratosphere’..and..the companion term ‘troposphere’... The term ‘ionosphere’, for the region in which the main characteristic is large scale ionisation with considerable mean free paths, appears appropriate as an addition to this series.

Edward V. Appleton was awarded a Nobel Prize in 1947 for his confirmation in 1927 of the existence of the ionosphere. Lloyd Berknerfirst measured the height and density of the ionosphere. This permitted the first complete theory of short wave radio propagation.Maurice V. Wilkes and J. A. Ratcliffe researched the topic of radio propagation of very long radio waves in the ionosphere. Vitaly Ginzburg has developed a theory of electromagnetic wave propagation in plasmas such as the ionosphere.

In 1962 the Canadian satellite Alouette 1 was launched to study the ionosphere. Following its success were Alouette 2 in 1965 and the two ISIS satellites in 1969 and 1971, all for measuring the ionosphere.

HAARP

2010-09-11T05:15:00.000-07:00

This article was prepared to provide a summary of the contents of a book written in 1995 which describes an entirely new class of weapons. The weapons and their effects are described in the following pages. The United States Navy and Air Force have joined with the University of Alaska, Fairbanks, to build a prototype for a ground based "Star Wars" weapon system located in the remote bush country of Alaska.

The individuals who are demanding answers about HAARP are scattered around the planet. As well as bush dwellers in Alaska, they include: a physician in Finland; a scientist in Holland; an anti-nuclear protester in Australia; independent physicists in the United States; a grandmother in Canada, and countless others.

Unlike the protests of the 1960s the objections to HAARP have been registered using the tools of the 1990s. From the Internet, fax machines, syndicated talk radio and a number of alternative print mediums the word is getting out and people are waking up to this new intrusion by an over zealous United States government.

The research team put together to gather the materials which eventually found their way into the book never held a formal meeting, never formed a formal organization. Each person acted like a node on a planetary info-spirit-net with one goal held by all -- to keep this controversial new science in the public eye. The result of the team's effort was a book which describes the science and the political ramifications of this technology.

That book, Angels Don't Play this HAARP: Advances in Tesla Technology, has 230 pages. This article will only give the highlights. Despite the amount of research (350 footnoted sources), at its heart it is a story about ordinary people who took on an extraordinary challenge in bringing their research forward.

HAARP Boils the Upper Atmosphere

HAARP will zap the upper atmosphere with a focused and steerable electromagnetic beam. It is an advanced model of an "ionospheric heater." (The ionosphere is the electrically-charged sphere surrounding Earth's upper atmosphere. It ranges between 40 to 60 miles above the surface of the Earth.)

Put simply, the apparatus for HAARP is a reversal of a radio telescope; antenna send out signals instead of receiving. HAARP is the test run for a super-powerful radiowave-beaming technology that lifts areas of the ionosphere by focusing a beam and heating those areas. Electromagnetic waves then bounce back onto earth and penetrate everything -- living and dead.

HAARP publicity gives the impression that the High-frequency Active Auroral Research Program is mainly an academic project with the goal of changing the ionosphere to improve communications for our own good. However, other U.S. military documents put it more clearly -- HAARP aims to learn how to "exploit the ionosphere for Department of Defense purposes." Communicating with submarines is only one of those purposes.

Press releases and other information from the military on HAARP continually downplay what it could do. Publicity documents insist that the HAARP project is no different than other ionospheric heaters operating safely throughout the world in places such as Arecibo, Puerto Rico, Tromso, Norway, and the former Soviet Union. However, a 1990 government document indicates that the radio-frequency (RF) power zap will drive the ionosphere to unnatural activities.

" ... at the highest HF powers available in the West, the instabilities commonly studied are approaching their maximum RF energy dissipative capability, beyond which the plasma processes will 'runaway' until the next limiting factor is reached."

If the military, in cooperation with the University of Alaska Fairbanks, can show that this new ground-based "Star Wars" technology is sound, they both win. The military has a relatively-inexpensive defense shield and the University can brag about the most dramatic geophysical manipulation since atmospheric explosions of nuclear bombs. After successful testing, they would have the military megaprojects of the future and huge markets for Alaska's North Slope natural gas.

Looking at the other patents which built on the work of a Texas' physicist named Bernard Eastlund, it becomes clearer how the military intends to use the HAARP transmitter. It also makes governmental denials less believable. The military knows how it intends to use this technology, and has made it clear in their documents. The military has deliberately misled the public, through sophisticated word games, deceit and outright disinformation.

The military says the HAARP system could:

Give the military a tool to replace the electromagnetic pulse effect of atmospheric thermonuclear devices (still considered a viable option by the military through at least 1986)
Replace the huge Extremely Low Frequency (ELF) submarine communication system operating in Michigan and Wisconsin with a new and more compact technology
Be used to replace the over-the-horizon radar system that was once planned for the current location of HAARP, with a more flexible and accurate system
Provide a way to wipe out communications over an extremely large area, while keeping the military's own communications systems working
Provide a wide area earth-penetrating tomography which, if combined with the computing abilities of EMASS and Cray computers, would make it possible to verify many parts of nuclear nonproliferation and peace agreements
Be a tool for geophysical probing to find oil, gas and mineral deposits over a large area
Be used to detect incoming low-level planes and cruise missiles, making other technologies obsolete

The above abilities seem like a good idea to all who believe in sound national defense, and to those concerned about cost-cutting. However, the possible uses which the HAARP records do not explain, and which can only be found in Air Force, Army, Navy and other federal agency records, are alarming. Moreover, effects from the reckless use of these power levels in our natural shield -- the ionosphere -- could be cataclysmic according to some scientists.

Two Alaskans put it bluntly. A founder of the NO HAARP movement, Clare Zickuhr, says "The military is going to give the ionosphere a big kick and see what happens."
The military failed to tell the public that they do not know what exactly will happen, but a Penn State science article brags about that uncertainty. Macho science? The HAARP project uses the largest energy levels yet played with by what Begich and Manning call "the big boys with their new toys." HAARP is an experiment in the sky, and experiments are done to find out something not already known. Independent scientists told Begich and Manning that a HAARP-type "skybuster" with its unforeseen effects could be an act of global vandalism.

HAARP History

The patents described below were the package of ideas which were originally controlled by ARCO Power Technologies Incorporated (APTI), a subsidiary of Atlantic Richfield Company, one of the biggest oil companies in the world. APTI was the contractor that built the HAARP facility. ARCO sold this subsidiary, the patents and the second phase construction contract to E-Systems in June 1994.

E-Systems is one of the biggest intelligence contractors in the world -- doing work for the CIA, defense intelligence organizations and others. $1.8 billion of their annual sales are to these organizations, with $800 million for black projects -- projects so secret that even the United States Congress isn't told how the money is being spent.
E-Systems was bought out by Raytheon, which is one of the largest defense contractors in the world. In 1994 Raytheon was listed as number forty-two on the Fortune 500 list of companies. Raytheon has thousands of patents, some of which will be valuable in the HAARP project. The twelve patents below are the backbone of the HAARP project, and are now buried among the thousands of others held in the name of Raytheon. Bernard J. Eastlund's U.S. Patent # 4,686,605, "Method and Apparatus for Altering a Region in the Earth's Atmosphere, Ionosphere; and/or Magnetosphere," was sealed for a year under a government Secrecy Order.

The Eastlund ionospheric heater was different; the radio frequency (RF) radiation was concentrated and focused to a point in the ionosphere. This difference throws an unprecedented amount of energy into the ionosphere. The Eastlund device would allow a concentration of one watt per cubic centimeter, compared to others only able to deliver about one millionth of one watt.

This huge difference could lift and change the ionosphere in the ways necessary to create futuristic effects described in the patent. According to the patent, the work of Nikola Tesla in the early 1900's formed the basis of the research.

What would this technology be worth to ARCO, the owner of the patents? They could make enormous profits by beaming electrical power from a powerhouse in the gas fields to the consumer without wires.

For a time, HAARP researchers could not prove that this was one of the intended uses for HAARP. In April, 1995, however, Begich found other patents, connected with a "key personnel" list for APTI. Some of these new APTI patents were indeed a wireless system for sending electrical power. Eastlund's patent said the technology can confuse or completely disrupt airplanes' and missiles' sophisticated guidance systems. Further, this ability to spray large areas of Earth with electromagnetic waves of varying frequencies, and to control changes in those waves, makes it possible to knock out communications on land or sea as well as in the air.

The patent said:

"Thus, this invention provides the ability to put unprecedented amounts of power in the Earth's atmosphere at strategic locations and to maintain the power injection level particularly if random pulsing is employed, in a manner far more precise and better controlled than heretofore accomplished by the prior art, particularly by detonation of nuclear devices of various yields at various altitudes... "

"...it is possible not only to interfere with third party communications but to take advantage of one or more such beams to carry out a communications network even though the rest of the world's communications are disrupted. Put another way, what is used to disrupt another's communications can be employed by one knowledgeable of this invention as a communication network at the same time."

"... large regions of the atmosphere could be lifted to an unexpectedly high altitude so that missiles encounter unexpected and unplanned drag forces with resultant destruction."

"Weather modification is possible by, for example, altering upper atmosphere wind patterns by constructing one or more plumes of atmospheric particles which will act as a lens or focusing device.

... molecular modifications of the atmosphere can take place so that positive environmental effects can be achieved. Besides actually changing the molecular composition of an atmospheric region, a particular molecule or molecules can be chosen for increased presence. For example, ozone, nitrogen, etc., concentrations in the atmosphere could be artificially increased."

Begich found eleven other APTI Patents. They told how to make "Nuclear-sized Explosions without Radiation," Power-beaming systems, over-the-horizon radar, detection systems for missiles carrying nuclear warheads, electromagnetic pulses previously produced by thermonuclear weapons and other Star-Wars tricks. This cluster of patents underlay the HAARP weapon system.

Related research by Begich and Manning uncovered bizarre schemes. For example, Air Force documents revealed that a system had been developed for manipulating and disturbing human mental processes through pulsed radio-frequency radiation (the stuff of HAARP) over large geographical areas. The most telling material about this technology came from writings of Zbigniew Brzezinski (former National Security Advisory to U.S. President Carter) and J.F. MacDonald (science advisor to U.S. President Johnson and a professor of Geophysics at UCLA), as they wrote about use of power-beaming transmitters for geophysical and environmental warfare. The documents showed how these effects might be caused, and the negative effects on human heath and thinking.

The mental-disruption possibilities for HAARP are the most disturbing. More than 40 pages of the book, with dozens of footnotes, chronicle the work of Harvard professors, military planners and scientists as they plan and test this use of the electromagnetic technology. For example, one of the papers describing this use was from the International Red Cross in Geneva. It even gave the frequency ranges where these effects could occur -- the same ranges which HAARP is capable of broadcasting.

The following statement was made more than twenty-five years ago in a book by Brzezinski which he wrote while a professor at Columbia University:

"Political strategists are tempted to exploit research on the brain and human behavior. Geophysicist Gordon J.F. MacDonald, a specialist in problems of warfare, says accurately-timed, artificially-excited electronic strokes could lead to a pattern of oscillations that produce relatively high power levels over certain regions of the earth ... in this way one could develop a system that would seriously impair the brain performance of very large populations in selected regions over an extended period"

" ... no matter how deeply disturbing the thought of using the environment to manipulate behavior for national advantages, to some, the technology permitting such use will very probably develop within the next few decades."

In 1966, MacDonald was a member of the President's Science Advisory Committee and later a member of the President's Council on Environmental Quality. He published papers on the use of environmental control technologies for military purposes. The most profound comment he made as a geophysicist was, "the key to geophysical warfare is the identification of environmental instabilities to which the addition of a small amount of energy would release vastly greater amounts of energy." While yesterday's geophysicists predicted today's advances, are HAARP program managers delivering on the vision?

The geophysicists recognized that adding energy to the environmental soup could have large effects. However, humankind has already added substantial amounts of electromagnetic energy into our environment without understanding what might constitute critical mass. The book by Begich and Manning raises questions:

Have these additions been without effect, or is there a cumulative amount beyond which irreparable damage can be done?
Is HAARP another step in a journey from which we cannot turn back?
Are we about to embark on another energy experiment which unleashes another set of demons from Pandora's box?

As early as 1970, Zbigniew Brzezinski predicted a "more controlled and directed society" would gradually appear, linked to technology. This society would be dominated by an elite group which impresses voters by allegedly superior scientific know-how. Angels Don't Play This HAARP further quotes Brzezinski:

"Unhindered by the restraints of traditional liberal values, this elite would not hesitate to achieve its political ends by using the latest modern techniques for influencing public behavior and keeping society under close surveillance and control. Technical and scientific momentum would then feed on the situation it exploits," Brzezinski predicted.

His forecasts proved accurate. Today, a number of new tools for the "elite" are emerging, and the temptation to use them increases steadily. The policies to permit the tools to be used are already in place. How could the United States be changed, bit by bit, into the predicted highly-controlled technosociety? Among the "steppingstones" Brzezinski expected were persisting social crises and use of the mass media to gain the public's confidence.

In another document prepared by the government, the U.S. Air Force claims: "The potential applications of artificial electromagnetic fields are wide-ranging and can be used in many military or quasi-military situations... Some of these potential uses include dealing with terrorist groups, crowd control, controlling breaches of security at military installations, and antipersonnel techniques in tactical warfare. In all of these cases the EM (electromagnetic) systems would be used to produce mild to severe physiological disruption or perceptual distortion or disorientation. In addition, the ability of individuals to function could be degraded to such a point that they would be combat ineffective. Another advantage of electromagnetic systems is that they can provide coverage over large areas with a single system. They are silent and countermeasures to them may be difficult to develop... One last area where electromagnetic radiation may prove of some value is in enhancing abilities of individuals for anomalous phenomena."

Do these comments point to uses already somewhat developed? The author of the government report refers to an earlier Air Force document about the uses of radio frequency radiation in combat situations. (Here Begich and Manning note that HAARP is the most versatile and the largest radio-frequency-radiation transmitter in the world.)

The United States Congressional record deals with the use of HAARP for penetrating the earth with signals bounced off of the ionosphere. These signals are used to look inside the planet to a depth of many kilometers in order to locate underground munitions, minerals and tunnels. The U.S. Senate set aside $15 million dollars in 1996 to develop this ability alone -- earth-penetrating-tomography. The problem is that the frequency needed for earth-penetrating radiation is within the frequency range most cited for disruption of human mental functions. It may also have profound effects on migration patterns of fish and wild animals which rely on an undisturbed energy field to find their routes.

As if electromagnetic pulses in the sky and mental disruption were not enough, T. Eastlund bragged that the super-powerful ionospheric heater could control weather.

Begich and Manning brought to light government documents indicating that the military has weather-control technology. When HAARP is eventually built to its full power level, it could create weather effects over entire hemispheres. If one government experiments with the world's weather patterns, what is done in one place will impact everyone else on the planet. Angels Don't Play This HAARP explains a principle behind some of Nikola Tesla's inventions -- resonance -- which affect planetary systems.

Bubble of Electric Particles

Angels Don't Play This HAARP includes interviews with independent scientists such as Elizabeth Rauscher. She has a Ph.D., a long and impressive career in high-energy physics, and has been published in prestigious science journals and books. Rauscher commented on HAARP. "You're pumping tremendous energy into an extremely delicate molecular configuration that comprises these multi-layers we call the ionosphere."
&QUOTThe ionosphere is prone to catalytic reactions," she explained, "if a small part is changed, a major change in the ionosphere can happen."

In describing the ionosphere as a delicately balanced system, Dr. Rauscher shared her mental picture of it -- a soap-bubble-like sphere surrounding Earth's atmosphere, with movements swirling over the surface of the bubble. If a big enough hole is punched through it, she predicts, it could pop.

Slicing the Ionosphere

Physicist Daniel Winter, Ph.D., of Waynesville, North Carolina, says, "HAARP high-frequency emissions can couple with longwave (extremely-low-frequency, or ELF) pulses the Earth grid uses to distribute information as vibrations to synchronize dances of life in the biosphere." Dan terms this geomagnetic action 'Earth's information bloodstream,' and says it is likely that coupling of HAARP HF (high-frequency) with natural ELF can cause unplanned, unsuspected side effects.

David Yarrow of Albany, New York, is a researcher with a background in electronics. He described possible interactions of HAARP radiation with the ionosphere and Earth's magnetic grid: "HAARP will not burn holes in the ionosphere. That is a dangerous understatement of what HAARP's giant gigawatt beam will do. Earth is spinning relative to thin electric shells of the multilayer membrane of ion-o-speres that absorb and shield Earth's surface from intense solar radiation, including charged particle storms in solar winds erupting from the sun. Earth's axial spin means that HAARP -- in a burst lasting more than a few minutes -- will slice through the ionosphere like a microwave knife. This produces not a hole but a long tear -- an incision."

Crudely Plucking the Strings

Second concept: As Earth rotates, HAARP will slice across the geomagnetic flux, a donut-shaped spool of magnetic strings -- like longitude meridians on maps.
HAARP may not 'cut' these strings in Gaia's magnetic mantle, but will pulse each thread with harsh, out-of-harmony high frequencies. These noisy impulses will vibrate geomagnetic flux lines, sending vibrations all through the geomagnetic web. "

"The image comes to mind of a spider on its web. An insect lands, and the web's vibrations alert the spider to possible prey. HAARP will be a man-made microwave finger poking at the web, sending out confusing signals, if not tearing holes in the threads. "
"Effects of this interference with symphonies of Gaia's geomagnetic harp are unknown, and I suspect barely thought of. Even if thought of, the intent (of HAARP) is to learn to exploit any effects, not to play in tune to global symphonies. "

Among other researchers quoted is Paul Schaefer of Kansas City. His degree is in electrical engineering and he spent four years building nuclear weapons. "But most of the theories that we have been taught by scientists to believe in seem to be falling apart," he says. He talks about imbalances already caused by the industrial and atomic age, especially by radiation of large numbers of tiny, high-velocity particles "like very small spinning tops" into our environment. The unnatural level of motion of highly-energetic particles in the atmosphere and in radiation belts surrounding Earth is the villain in the weather disruptions, according to this model, which describes an Earth discharging its buildup of heat, relieving stress and regaining a balanced condition through earthquakes and volcanic action.

Feverish Earth

"One might compare the abnormal energetic state of the Earth and its atmosphere to a car battery which has become overcharged with the normal flow of energy jammed up, resulting in hot spots, electrical arcing, physical cracks and general turbulence as the pent-up energy tries to find some place to go."

In a second analogy, Schaefer says "Unless we desire the death of our planet, we must end the production of unstable particles which are generating the earth's fever. A first priority to prevent this disaster would be to shut down all nuclear power plants and end the testing of atomic weapons, electronic warfare and 'Star Wars'." Meanwhile, the military builds its biggest ionospheric heater yet, to deliberately create more instabilities in a huge plasma layer -- the ionosphere -- and to rev up the energy level of charged particles.

Electronic Rain From The Sky

They have published papers about electron precipitation from the magnetosphere (the outer belts of charged particles which stream toward Earth's magnetic poles) caused by man-made very low frequency electromagnetic waves. "These precipitated particles can produce secondary ionization, emit X-rays, and cause significant perturbation in the lower ionosphere."

Two Stanford University radio scientists offer evidence of what technology can do to affect the sky by making waves on earth; they showed that very low frequency radio waves can vibrate the magnetosphere and cause high-energy particles to cascade into Earth's atmosphere. By turning the signal on or off, they could stop the flow of energetic particles.

Weather Control

Avalanches of energy dislodged by such radio waves could hit us hard. Their work suggests that technicians could control global weather by sending relatively small 'signals' into the Van Allen belts (radiation belts around Earth). Thus Tesla's resonance effects can control enormous energies by tiny triggering signals.
The Begich/ Manning book asks whether that knowledge will be used by war-oriented or biosphere-oriented scientists.

The military has had about twenty years to work on weather warfare methods, which it euphemistically calls weather modification. For example, rainmaking technology was taken for a few test rides in Vietnam. The U.S. Department of Defense sampled lightning and hurricane manipulation studies in Project Skyfire and Project Stormfury. And they looked at some complicated technologies that would give big effects. Angels Don't Play This HAARP cites an expert who says the military studied both lasers and chemicals which they figured could damage the ozone layer over an enemy. Looking at ways to cause earthquakes, as well as to detect them, was part of the project named Prime Argus, decades ago. The money for that came from the Defense Advanced Research Projects Agency (DARPA, now under the acronym ARPA.) In 1994 the Air Force revealed its Spacecast 2020 master plan which includes weather control. Scientists have experimented with weather control since the 1940's, but Spacecast 2020 noted that "using environmental modification techniques to destroy, damage or injure another state are prohibited." Having said that, the Air Force claimed that advances in technology "compels a reexamination of this sensitive and potentially risky topic."

40 Years of Zapping the Sky?

As far back as 1958, the chief White House advisor on weather modification, Captain Howard T. Orville, said the U.S. defense department was studying "ways to manipulate the charges of the earth and sky and so affect the weather" by using an electronic beam to ionize or de-ionize the atmosphere over a given area.

In 1966, Professor Gordon J. F. MacDonald was associate director of the Institute of Geophysics and Planetary Physics at the University of California, Los Angeles, was a member of the President's Science Advisory Committee, and later a member of the President's Council on Environmental Quality.

He published papers on the use of environmental-control technologies for military purposes. MacDonald made a revealing comment: "The key to geophysical warfare is the identification of environmental instabilities to which the addition of a small amount of energy would release vastly greater amounts of energy. " World-recognized scientist MacDonald had a number of ideas for using the environment as a weapon system and he contributed to what was, at the time, the dream of a futurist. When he wrote his chapter, "How To Wreck The Environment," for the book Unless Peace Comes, he was not kidding around. In it he describes the use of weather manipulation, climate modification, polar ice cap melting or destabilization, ozone depletion techniques, earthquake engineering, ocean wave control and brain wave manipulation using the planet's energy fields.

He also said that these types of weapons would be developed and, when used, would be virtually undetectable by their victims. Is HAARP that weapon? The military's intention to do environmental engineering is well documented, U.S. Congress' subcommittee hearings on Oceans and International Environment looked into military weather and climate modification conducted in the early 1970's. "What emerged was an awesome picture of far-ranging research and experimentation by the Department of Defense into ways environmental tampering could be used as a weapon," said another author cited in Angles Don't Play This HAARP.

The revealed secrets surprised legislators. Would an inquiry into the state of the art of electromagnetic manipulation surprise lawmakers today? They may find out that technologies developed out of the HAARP experiments in Alaska could deliver on Gordon MacDonald's vision because leading-edge scientists are describing global weather as not only air pressure and thermal systems, but also as an electrical system.

Small Input - Big Effect

HAARP zaps the ionosphere where it is relatively unstable. A point to remember is that the ionosphere is an active electrical shield protecting the planet from the constant bombardment of high-energy particles from space. This conducting plasma, along with Earth's magnetic field, traps the electrical plasma of space and holds it back from going directly to the earth's surface, says Charles Yost of Dynamic Systems, Leicester, North Carolina. "If the ionosphere is greatly disturbed, the atmosphere below is subsequently disturbed."

Another scientist interviewed said there is a super-powerful electrical connection between the ionosphere and the part of the atmosphere where our weather comes onstage, the lower atmosphere.

One man-made electrical effect -- power line harmonic resonance -- causes fallout of charged particles from the Van Allen (radiation) belts, and the falling ions cause ice crystals (which precipitate rain clouds). What about HAARP? Energy blasted upward from an ionospheric heater is not much compared to the total in the ionosphere, but HAARP documents admit that thousandfold-greater amounts of energy can be released in the ionosphere than injected. As with MacDonald's "key to geophysical warfare," "nonlinear" effects (described in the literature about the ionospheric heater) mean small input and large output. Astrophysicist Adam Trombly told Manning that an acupuncture model is one way to look at the possible effect of multi-gigawatt pulsing of the ionosphere. If HAARP hits certain points, those parts of the ionosphere could react in surprising ways.

Smaller ionospheric heaters such as the one at Arecibo are underneath relatively placid regions of the ionosphere, compared to the dynamic movements nearer Earth's magnetic poles. That adds another uncertainty to HAARP -- the unpredictable and lively upper atmosphere near the North Pole.

HAARP experimenters do not impress commonsense Alaskans such as Barbara Zickuhr, who says "They're like boys playing with a sharp stick, finding a sleeping bear and poking it in the butt to see what's going to happen."

Could They Short-Circuit Earth?

Earth as a spherical electrical system is a fairly well-accepted model. However, those experimenters who want to make unnatural power connections between parts of this system might not be thinking of possible consequences. Electrical motors and generators can be caused to wobble when their circuits are affected. Could human activities cause a significant change in a planet's electrical circuit or electrical field? A paper in the respected journal Science deals with manmade ionization from radioactive material, but perhaps it could also be studied with HAARP-type skybusters in mind:

"For example, while changes in the earth's electric field resulting from a solar flare modulating conductivity may have only a barely detectable effect on meteorology, the situation may be different in regard to electric field changes caused by manmade ionization... " Meteorology, of course, is the study of the atmosphere and weather. ionization is what happens when a higher level of power is zapped into atoms and knocks electrons off the atoms. The resulting charged particles are the stuff of HAARP. "One look at the weather should tell us that we are on the wrong path," says Paul Schaefer, commenting on HAARP-type technologies.

Angels Don't Play This HAARP: Advances in Tesla Technology is about the military's plan to manipulate that which belongs to the world -- the ionosphere. The arrogance of the United States government in this is not without precedent.

Atmospheric nuclear tests had similar goals. More recently, China and France put their people's money to destructive use in underground nuclear tests. It was recently reported that the US government spent $3 trillion dollars on its nuclear program since its beginnings in the 1940's. What new breakthroughs in life science could have been made with all the money spent on death?

Begich, Manning, Roderick and others believe that democracies need to be founded on openness, rather than the secrecy which surrounds so much military science. Knowledge used in developing revolutionary weapons could be used for healing and helping mankind. Because they are used in new weapons, discoveries are classified and suppressed. When they do appear in the work of other independent scientists, the new ideas are often frustrated or ridiculed, while military research laboratories continue to build their new machines for the killing fields.

However, the book by Manning and Begich gives hope that the military industrial academic bureaucratic Goliath can be affected by the combined power of determined individuals and the alternative press. Becoming informed is the first step to empowerment.

Suez Canal

2010-07-20T09:22:00.000-07:00

Suez Canal

The Suez Canal is an artificial sea-level waterway in Egypt, connecting the Mediterranean Sea and the Red Sea. Opened in November 1869, it allows water transportation between Europe and Asia without navigating around Africa. The northern terminus is Port Said and the southern terminus is Port Tawfik at the city of Suez. Ismailia lies on its west bank, 3 km (1.9 mi) north of the half-way point.

When first built, the canal was 164 km (102 mi) long and 8 m (26 ft) deep. After multiple enlargements, the canal is 193.30 km (120.11 mi) long, 24 m (79 ft) deep, and 205 metres (673 ft) wide as of 2010. It consists of the northern access channel of 22 km/14 mi, the canal itself of 162.25 km/100.82 mi and of the southern access channel of 9 km/5.6 mi.

It is single-lane with passing places in Ballah By-Pass and in the Great Bitter Lake. It contains no locks; seawater flows freely through the canal. In general, the Canal north of the Bitter Lakes flows north in winter and south in summer. The current south of the lakes changes with the tide at Suez.

The canal is owned and maintained by the Suez Canal Authority (SCA) of the Arab Republic of Egypt. Under international treaty, it may be used "in time of war as in time of peace, by every vessel of commerce or of war, without distinction of flag."

History of Suez Canal

Ancient west-east canals have facilitated travel from the Nile to the Red Sea. One smaller canal is believed to have been constructed under the auspices of either Senusret II or Ramesses II. Another canal probably incorporating a portion of the first was constructed under the reign of Necho II and completed by Darius.

2nd millennium BC

The legendary Sesostris (likely either Pharaoh Senusret II or Senusret III of the Twelfth dynasty of Egypt) is suggested to have perhaps started work on an ancient canal joining the River Nile with the Red Sea (1897 BC–1839 BC). (It is said that in ancient times the Red Sea reached northward to the Bitter Lakes and Lake Timsah.)

In his Meteorology, Aristotle wrote:

One of their kings tried to make a canal to it (for it would have been of no little advantage to them for the whole region to have become navigable; Sesostris is said to have been the first of the ancient kings to try), but he found that the sea was higher than the land. So he first, and Darius afterwards, stopped making the canal, lest the sea should mix with the river water and spoil it.

Strabo also wrote that Sesostris started to build a canal, and Pliny the Elder wrote:

165. Next comes the Tyro tribe and, on the Red Sea, the harbour of the Daneoi, from which Sesostris, king of Egypt, intended to carry a ship-canal to where the Nile flows into what is known as the Delta; this is a distance of over 60 miles. Later the Persian king Darius had the same idea, and yet again Ptolemy II, who made a trench 100 feet wide, 30 feet deep and about 35 miles long, as far as the Bitter Lakes.

French cartographers discovered the remnants of an ancient north-south canal running past the east side of Lake Timsah and ending near the north end of the Great Bitter Lake in the second half of the 19th century. (This ancient, second, canal may have followed a course along the shoreline of the Red Sea when the Red Sea once extended north to Lake Timsah.) In the 20th century the northward extension of this ancient canal was discovered, extending from Lake Timsah to the Ballah Lakes, which was subsequently dated to the Middle Kingdom of Egypt by extrapolating the dates of ancient sites erected along its course. However it remains unknown whether or not this is the same as Sesostris' ancient canal and whether it was used as a waterway or as a defence against the east.

The reliefs of the Punt expedition under Hatshepsut 1470 BC depict seagoing vessels carrying the expeditionary force returning from Punt. This has given rise to the suggestion that, at the time, a navigable link existed between the Red Sea and the Nile. Evidence seems to indicate its existence by the 13th century BC during the time of Ramesses II.

Canals dug by Necho, Darius I and Ptolemy

Remnants of an ancient west-east canal, running through the ancient Egyptian cities of Bubastis, Pi-Ramesses, and Pithom were discovered by Napoleon Bonaparte and his cadre of engineers and cartographers in 1799.

According to the Histories of the Greek historian Herodotus, about 600 BC, Necho II undertook to dig a west-east canal through the Wadi Tumilat between Bubastis and Heroopolis, and perhaps continued it to the Heroopolite Gulf and the Red Sea. Regardless, Necho is reported as having never completed his project.

Herodotus was told that 120,000 men perished in this undertaking, but this figure is doubtless exaggerated. According to Pliny the Elder, Necho's extension to the canal was approximately 57 English miles, equal to the total distance between Bubastis and the Great Bitter Lake, allowing for winding through valleys that it had to pass through. The length that Herodotus tells us, of over 1000 stadia (i.e., over 114 miles), must be understood to include the entire distance between the Nile and the Red Seaat that time.

With Necho's death, work was discontinued. Herodotus tells us that the reason the project was abandoned was because of a warning received from an oracle that others would benefit by its successful completion. In fact, Necho's war with Nebuchadrezzar II most probably prevented the canal to be continued.

Necho's project was finally completed by Darius I of Persia, who conquered Egypt. We are told that by Darius's time a natural waterway passage which had existed between the Heroopolite Gulf and the Red Sea in the vicinity of the Egyptian town of Shaluf (alt. Chalouf or Shaloof), located just south of the Great Bitter Lake, had become so blocked with silt that Darius needed to clear it out so as to allow navigation once again. According to Herodotus, Darius's canal was wide enough that two triremes could pass each other with oars extended, and required four days to traverse. Darius commemorated his achievement with a number of granite stelae that he set up on the Nile bank, including one near Kabret, and a further one a few miles north of Suez. The Darius Inscriptions read:

“

Saith King Darius: I am a Persian. Setting out from Persia, I conquered Egypt. I ordered this canal dug from the river called the Nile that flows in Egypt, to the sea that begins in Persia. When the canal had been dug as I ordered, ships went from Egypt through this canal to Persia, even as I intended.

”

The canal left the Nile at Bubastis. An inscription on a pillar at Pithom records that in 270 or 269 BC it was again reopened, by Ptolemy II Philadelphus. In Arsinoe, Ptolemy constructed a navigable lock, with sluices, at the Heroopolite Gulf of the Red Seawhich allowed the passage of vessels but prevented salt water from the Red Sea from mingling with the fresh water in the canal.

Receding Red Sea and the dwindling Nile

The Red Sea is believed by some historians to have gradually receded over the centuries, its coastline slowly moving farther and farther southward away from Lake Timsah and the Great Bitter Lake to its present coastline today. Coupled with persistent accumulations of Nile silt, maintenance and repair of Ptolemy's canal became increasingly cumbersome over each passing century.

Two hundred years after the construction of Ptolemy's canal, Cleopatra seems to have had no west-east waterway passage, because the Pelusiac branch of the Nile River, which had fed Ptolemy's west-east canal, had by that time dwindled, being choked with silt.

Topographic map, northern Gulf of Suez, route to Cairo, 1856.

Old Cairo to the Red Sea

By the 8th century, a navigable canal existed between Old Cairo and the Red Sea, but accounts vary as to who ordered its construction—either Trajan or 'Amr ibn al-'As, or Omar the Great. This canal reportedly linked to the River Nile at Old Cairo and ended near modern Suez.

The Abbasid Caliph al-Mansur is said to have ordered this canal closed so as to prevent supplies from reaching Arabian detractors.

Repair by Tāriqu l-Ḥākim

Al-Hakim bi-Amr Allah is claimed to have repaired the Old Cairo to Red Sea passageway, but only briefly, circa 1000 AD, as it soon "became choked with sand." However, we are told that parts of this canal still continued to fill in during the Nile's annual inundations.

Napoleon discovers an ancient canal

Napoleon Bonaparte's interest in finding the remnants of an ancient waterway passageculminated in a cadre of archaeologists, scientists, cartographers and engineers scouring the area beginning in the latter months of 1798. Their findings, recorded in the Description de l'Égypte, include detailed maps that depict the discovery of an ancient canal extending northward from the Red Sea and then westward toward the Nile.

The Suez Canal at Ismailia, c. 1860. The Ismailia segment was completed in November 1862.

Napoleon had contemplated the construction of another, modern, north-south canal to join the Mediterranean and Red Sea. But his project was abandoned after the preliminary survey erroneously concluded that the Red Sea was 10 metres (33 ft) higher than the Mediterranean, making a locks-based canal too expensive and very long to construct. The Napoleonic survey commission's error came from fragmented readings mostly done during wartime, which resulted in imprecise calculations.

1881 drawing of the Suez Canal.

Though by this time unnavigable, the ancient route from Bubastis to the Red Sea still channeled water in spots as late as 1861 and as far east as Kassassin.

Interim Period

Although the difference in the sea levels (which could be problematic for a canal's construction there) had been noted for some time, the idea of finding a shorter route to the east remained alive. In 1830, F. R. Chesney submitted a report to the British government, which stated that there was no difference in altitude, and that the Suez Canal was feasible, but his report received no further attention. Lieutenant Waghorn established his Overland Route, which transported post and passengers to India via Egypt. Linant de Bellefonds, a French explorer of Egypt, became chief engineer of Egypt's Public Works. In addition to his normal duties, he surveyed the Isthmus of Suez and made plans for the Suez Canal. French Saint-Simonianists showed an interest in the canal and in 1833, Barthélemy Prosper Enfantin tried to draw Muhammad Ali's attention to the canal but was unsuccessful. Alois Negrelli, the Austrian railroad pioneer, became interested in the idea in 1836. In 1846, Prosper Enfantin's Société d'Études du Canal de Suez invited a number of experts, among them Robert Stephenson, Negrelli and Paul-Adrien Bourdaloue to study the feasibility of the Suez Canal (with the assistance of Linant de Bellefonds). Bourdaloue's survey of the isthmus was the first generally accepted evidence that there was no practical difference in altitude between the two seas. Britain, however, feared that a canal open to everyone might interfere with its India trade and, therefore, preferred a connection by train from Alexandria via Cairo to Suez, which eventually was built by Stephenson.

Construction by Suez Canal Company

In 1854 and 1856 Ferdinand de Lesseps obtained a concession from Sa'id Pasha, the viceroy of Egypt, to create a company to construct a canal open to ships of all nations. The company was to operate the canal for 99 years from its opening. De Lesseps had used his friendly relationship with Sa'id, which he had developed while he was a French diplomat during the 1830s. As stipulated in the concessions, Lesseps convened the International Commission for the piercing of the isthmus of Suez (Commission Internationale pour le percement de l'isthme des Suez) consisting of thirteen experts from seven countries, among them McClean, President of the Institution of Civil Engineers in London, and again Negrelli, to examine the plans of Linant de Bellefonds and to advise on the feasibility of and on the best route for the canal. After surveys and analyses in Egypt and discussions in Paris on various aspects of the canal, where many of Negrelli's ideas prevailed, the commission produced a final unanimous report in December 1856 containing a detailed description of the canal complete with plans and profiles. The Suez Canal Company (Compagnie Universelle du Canal Maritime de Suez) came into being on 15 December 1858 and work started on the shore of the future Port Said on 25 April 1859.

The excavation took some 10 years using forced labour (Corvée) of Egyptian workers during a certain period. Some sources estimate that over 30,000 people were working on the canal at any given period, that altogether more than 1.5 million people from various countries were employed, and that thousands of laborers died on the project.

The British government had opposed the project of the canal from the outset to its completion. As one of the diplomatic moves against the canal, it disapproved the use of slave labor on the canal (slaves had been banned throughout Europe by 1830). The British Empire was the major global naval force and officially condemned the forced work and sent armed bedouins to start a revolt among workers. Involuntary labour on the project ceased, and the viceroy condemned the Corvée, halting the project.

Angered by the British opportunism, de Lesseps sent a letter to the British government remarking on the British lack of remorse a few years earlier when forced workers died in similar conditions building the British railway in Egypt.

Initially international opinion was skeptical and Suez Canal Company shares did not sell well overseas. Britain, the United States, Austria and Russia did not buy any significant number of shares. All French shares were quickly sold in France. A contemporary British sceptic claimed:

“

One thing is sure... our local merchant community doesn't pay practical attention at all to this grand work, and it is legitimate to doubt that the canal's receipts... could ever be sufficient to recover its maintenance fee. It will never become a large ships accessible way in any case. (reported by German historian Uwe A. Oster)

”

One of the first traverses in the 19th century.

Suez Canal in February 1934. Air photograph taken by Swiss pilot and photographer Walter Mittelholzer.

The canal opened to shipping on 17 November 1869. Although numerous technical, political, and financial problems had been overcome, the final cost was more than double the original estimate.

After the opening of the canal, the Suez Canal Company was in financial difficulties. The remaining works were completed only in 1871, and traffic was below expectations in the first two years. Lesseps therefore tried to increase revenues by interpreting the kind of net ton referred to in the second concession (tonneau de capacité) as meaning a ship's real freight capacity and not only the theoretical net tonnage of the Moorsom System introduced in Britain by the Merchant Shipping Act in 1854. The ensuing commercial and diplomatic activities resulted in the International Commission of Constantinople establishing a specific kind of net tonnage and settling the question of tariffs in their protocol of 18 December 1873. This was the origin of the Suez Canal Net Tonnage and the Suez Canal Special Tonnage Certificate still used today.

The canal had an immediate and dramatic effect on world trade. Combined with the American transcontinental railroad completed six months earlier, it allowed the entire world to be circled in record time. It played an important role in increasing European colonisation of Africa. External debts forced Said Pasha's successor, Isma'il Pasha, to sell his country's share in the canal for £4,000,000 to the United Kingdom in 1875, but French shareholders still held the majority. Prime Minister Benjamin Disraeli was accused by William Ewart Gladstone of undermining Britain's constitutional system, due to his lack of reference or consent from Parliament when purchasing the shares with funding from the Rothschilds.

The Convention of Constantinople in 1888 declared the canal a neutral zone under the protection of the British; British troops had moved in to protect it during a civil war in Egypt in 1882. They were later to defend the strategically important passage against a major Ottoman attack in 1915. Under the Anglo-Egyptian Treaty of 1936, the United Kingdom insisted on retaining control over the canal. In 1951 Egypt repudiated the treaty, and in 1954 the UK agreed to remove its troops, and withdrawal was completed in July 1956.

Suez Crisis

After the United Kingdom and the United States withdrew their pledge to support the construction of the Aswan Dam due to Egyptian overtures towards the Soviet Union, Egyptian President Gamal Abdel Nasser nationalised the canal in 1956 and transferred it to the Suez Canal Authority, intending to finance the dam project using revenue from the canal. This lead up to the Suez Crisis, in which the UK, France and Israel invaded Egypt. The intention was for Israel to invade on the ground, and for the Anglo-French partnership to give air and other support, later to intervene to resolve the crisis and control the canal.

To stop the war from spreading and to save the British from what he thought was a disastrous action, Canadian Secretary of State for External Affairs, Lester B. Pearson, proposed the creation of the very first United Nations peacekeeping force to ensure access to the canal for all and an Israeli withdrawal from the Sinai. On 4 November 1956, a majority of nations at the United Nations voted for Pearson's peacekeeping resolution, which mandated the UN peacekeepers to stay in the Sinai Peninsula unless both Egypt and Israel agreed to their withdrawal. The United States backed this proposal by putting pressure on the British government by selling Pounds, which would cause it to depreciate. Britain then agreed to withdraw its troops. Pearson was later awarded the Nobel Peace Prize. As a result of damage and ships intentionally sunk under orders from Nasser the canal was closed until April 1957, when it was cleared with UN assistance. A UN force (UNEF) was established to maintain the neutrality of the canal and the Sinai Peninsula.

Arab-Israeli wars of 1967 and 1973

In May 1967 President Nasser ordered the UN peacekeeping forces out of the Sinai Peninsula, including the Suez Canal area. Despite Israeli objections in the United Nations, the peacekeepers were withdrawn and the Egyptian army took up positions on the Israeli border, closing the Straits of Tiran to Israeli shipping. The canal itself had been closed to Israeli shipping since 1949, except for a short period in 1951-1952.

These actions were key factors in the Israeli decision to launch a pre-emptive attack on Egypt in June 1967, and to capture the Sinai Peninsula to the Suez Canal. After the 1967 Arab-Israeli war, also called the Six Day War, the canal was closed by an Egyptian blockade until 5 June 1975. As a result, fourteen cargo ships known as "The Yellow Fleet" remained trapped in the canal for over eight years. In 1973, during the Yom Kippur War, the canal was the scene of a major crossing by the Egyptian army into Israeli-occupied Sinai, and in the later stage of the war, a crossing by the Israeli army into mainland Egypt. Much wreckage from this conflict remains visible along the canal's edges.

A US Navy RH-53D sweeping the Suez Canal in 1974.

In reaction to the Yom Kippur War the United States initiated Operation Nimbus Moon. The helicopter carrier USS Iwo Jima (LPH-2) was sent to the Canal, carrying twelve RH-53D minesweeping helicopters of HM-12. These cleared the Suez Canal between May and December 1974. When the operations were completed, the Suez Canal and its lakes were considered 99% clear of mines. The Canal was then reopened in 1975.

The UNEF mandate expired in 1979. Despite the efforts of the United States, Israel, Egypt, and others to obtain an extension of the UN role in observing the peace between Israel and Egypt, as called for under the Egypt-Israel Peace Treaty of 1979, the mandate could not be extended because of the veto by the USSR in the security council, at the request of Syria. Accordingly, negotiations for a new observer force in the Sinai produced the Multinational Force and Observers (MFO), stationed in Sinai in 1981 in coordination with a phased Israeli withdrawal. It is there under agreements between the United States, Israel, Egypt, and other nations.

Capacity

Ships moored at El Ballah during transit

Main article: Suezmax

The canal allows passage of ships up to 20 m (66 ft) draft or 240,000 deadweight tons and up to a maximum height of 68 m (223 ft) above water level and a maximum beam of 77.5 m (254 ft) under certain conditions.

Some supertankers are too large. Others can offload part of their cargo onto a canal-owned boat to reduce their draft, transit, and reload at the other end of the canal.

Alternatives

The main alternative is travelling around Cape Agulhas at the south of the African continent. This was the only route before the canal was constructed, and—more recently—when the canal was closed. It is still the only route for ships which are too large for the canal. In the early twenty-first century the long route has enjoyed increased popularity because of increasing piracy in Somalia and high canal tolls.

Before the canal's opening in 1869 goods were sometimes offloaded from ships and carried overland between the Mediterranean and the Red Sea.

Operation

USS Bainbridge, an American warship in the Suez Canal

The canal has no locks due to the flat terrain, and the minor sea level difference between each end is inconsequential for shipping.

There is one shipping lane with passing areas in Ballah-Bypass near El Qantara and in the Great Bitter Lake. On a typical day, three convoys transit the canal, two southbound and one northbound. The first southbound convoy enters the canal in the early morning hours and proceeds to the Great Bitter Lake, where the ships anchor out of the fairway, awaiting passage of the northbound convoy. The northbound convoy passes the second southbound convoy, which moors in Ballah-Bypass . The passage takes between 11 and 16 hours at a speed of around 8 knots (15 km/h; 9 mph). The low speed helps prevent erosion of the canal banks by ships' wakes.

By 1955 approximately two-thirds of Europe's oil passed through the canal. About 7.5% of world sea trade is carried via the canal today. In 2008, a total of 21,415 vessels passed through the canal and the receipts from the canal totaled $5.381 billion. Average cost per-ship is roughly $251,000.00

New Rules of Navigation that constitute an improvement over the older ones were passed by the board of directors of the Suez Canal Authority (SCA) to organise vessels’ and tankers’ transit that came into force as at 1 January 2008.

The most important amendments to the Rules include allowing vessels with 62-foot (19 m) draught to transit and increasing the allowed breadth from 32 metres (105 ft) up to 40 metres (130 ft) following improvement operations, as well as imposing a fine on vessels using divers without permission from outside the SCA inside the canal boundaries.

The amendments also allow vessels loaded with dangerous cargo, such as radioactive or inflammable materials, to transit after bringing conformity with the latest amendments provided by international conventions.

The SCA will also have the right to determine the number of tugs required to assist warships transiting the Canal to achieve the highest degree of safety during transit.

The vast canal can handle more ship traffic and larger ships than the Panama Canal.

Connections between the shores

From north to south connections are:

The Suez Canal Bridge, also called the Egyptian-Japanese Friendship Bridge, is a high-level road bridge at El Qantara. In Arabic, al qantara means "the bridge". It has a 70-metre (230 ft) clearance over the canal and was built with assistance from the Japanese government and by PentaOcean Construction.
El Ferdan Railway Bridge 20 km (12 mi) north of Ismailia was completed in 2001 and is the longest swing span bridge in the world, with a span of 340 m (1100 ft). The previous bridge was destroyed in 1967 during the Arab-Israeli conflict.
Pipelines taking fresh water under the canal to Sinai, about 57 km (35 mi) north of Suez, at 30°27.3′N 32°21.0′E / 30.455°N 32.35°E / 30.455; 32.35.
Ahmed Hamdi Tunnel south of the Great Bitter Lake was built in 1983. Because of leakage problems, a new water-tight tunnel was built inside the old one, from 1992 to 1995.
The Suez Canal overhead line crossing powerline was built in 1999.

A railway on the west bank runs parallel to the canal for its entire length.

Environmental impact

Map of the Red Sea

The opening of the Suez Canal in 1869 created the first salt-water passage between the Mediterranean and Red seas. Although the Red Sea is about 1.2 m (3.9 ft) higher than the eastern Mediterranean, the current between the Mediterranean and the middle of the canal at the Bitter Lakes flows north in winter and south in summer. The current south of the Bitter Lakes is tidal, varying with the height of tide at Suez. The Bitter Lakes, which were hypersaline natural lakes, blocked the migration of Red Sea species into the Mediterranean for many decades, but as the salinity of the lakes gradually equalised with that of the Red Sea, the barrier to migration was removed, and plants and animals from the Red Sea have begun to colonise the eastern Mediterranean. The Red Sea is generally saltier and more nutrient-poor than the Atlantic, so the Red Sea species have advantages over Atlantic species in the salty and nutrient-poor eastern Mediterranean. Accordingly, most Red Sea species invade the Mediterranean biota, and only few do the opposite. This migratory phenomenon is called Lessepsian migration (after Ferdinand de Lesseps) or Erythrean invasion. The construction of the Aswan High Dam across the River Nile in the 1960s reduced the inflow of freshwater and nutrient-rich silt from the Nile into the eastern Mediterranean, making conditions there even more like the Red Sea, worsening the impact of the invasive species.

Invasive species originated from the Red Sea and introduced into the Mediterranean by the construction of the canal have become a major component of the Mediterranean ecosystem, and have serious impacts on the Mediterranean ecology, endangering many local and endemic Mediterranean species. Currently about 300 species from the Red Sea have been identified in the Mediterranean Sea, and there are probably others yet unidentified. The Egyptian government's intent to enlarge the canal have raised concerns from marine biologists, fearing that this will worsen the invasion of Red Sea species in the Mediterranean.

Construction of the Suez Canal was preceded by cutting a small fresh-water canal from the Nile delta along Wadi Tumilat to the future canal, with a southern branch to Suez and a northern branch to Port Said. Completed in 1863, these brought fresh water to a previously arid area, initially for canal construction, and subsequently facilitating growth of agriculture and settlements along the canal.

Octopus

2010-07-12T11:55:00.000-07:00

Octopus

The octopus is a cephalopod mollusk in the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms. Most octopuses have no internal or external skeleton, allowing them to squeeze through tight places. Octopuses are highly intelligent, probably the most intelligent of all invertebrates.
The octopus inhabits many diverse regions of the ocean, especially coral reefs. For defense against predators, they hide, flee quickly, expel ink, or use color-changing camouflage. An octopus trails its eight arms behind it as it swims. All octopuses are venomous, but only the small blue-ringed octopuses are deadly to humans.In the larger sense, there are around 300 recognized octopus species, which is over one-third of the total number of known cephalopod species. The term octopus may also be used to refer only to those creatures in the genus Octopus.
Biology

A Common Octopus (Octopus vulgaris)
Octopuses are characterized by their eight arms, usually bearing suction cups. The arms of octopuses are often distinguished from the pair of feeding tentacles found in squid and cuttlefish.[4] Both types of limbs are muscular hydrostats. Unlike most other cephalopods, the majority of octopuses – those in the suborder most commonly known, Incirrina – have almost entirely soft bodies with no internal skeleton. They have neither a protective outer shell like the nautilus, nor any vestige of an internal shell or bones, like cuttlefish or squid. A beak, similar in shape to a parrot's beak, is the only hard part of their body. This enables them to squeeze through very narrow slits between underwater rocks, which is very helpful when they are fleeing from morays or other predatory fish. The octopuses in the less familiar Cirrina suborder have two fins and an internal shell, generally reducing their ability to squeeze into small spaces.

An octopus moving between tide pools during low tide
Octopuses have a relatively short life expectancy, and some species live for as little as six months. Larger species, such as the North Pacific Giant Octopus, may live for up to five years under suitable circumstances. However, reproduction is a cause of death: males can only live for a few months after mating, and females die shortly after their eggs hatch. They neglect to eat during the (roughly) one month period spent taking care of their unhatched eggs, but they don't die of starvation. Endocrine secretions from the two optic glands are the cause of genetically programmed death (and if these glands are surgically removed, the octopus may live many months beyond reproduction, until she finally starves).

Stauroteuthis syrtensis, a finned octopus of the suborder Cirrina
Octopuses have three hearts. Two pump blood through each of the two gills, while the third pumps blood through the body. Octopus blood contains the copper-rich protein hemocyanin for transporting oxygen. Although less efficient under normal conditions than the iron-rich hemoglobin of vertebrates, in cold conditions with low oxygen pressure, hemocyanin oxygen transportation is more efficient than hemoglobin oxygen transportation. The hemocyanin is dissolved in the plasma instead of being carried within red blood cells and gives the blood a blue color. Octopuses draw water into their mantle cavity where it passes through its gills. As mollusks, octopuses have gills that are finely divided and vascularized outgrowths of either the outer or the inner body surface.
Intelligence
Main article: Cephalopod intelligence
Octopuses are highly intelligent, likely more so than any other order of invertebrates. The exact extent of their intelligence and learning capability is much debated among biologists, but maze and problem-solving experiments have shown that they do have both short- and long-term memory. Their short lifespans limit the amount they can ultimately learn. There has been much speculation to the effect that almost all octopus behaviors are independently learned rather than instinct-based, although this remains largely unproven. They learn almost no behaviors from their parents, with whom young octopuses have very little contact.

An octopus opening a container with a screw cap
An octopus has a highly complex nervous system, only part of which is localized in its brain. Two-thirds of an octopus's neurons are found in the nerve cords of its arms, which have a remarkable amount of autonomy. Octopus arms show a wide variety of complex reflex actions arising on at least three different levels of the nervous system. Unlike vertebrates, the complex motor skills of octopuses in their higher brain are not organized using an internal somatotopic map of its body. Some octopuses, such as the mimic octopus, will move their arms in ways that emulate the movements of other sea creatures.
In laboratory experiments, octopuses can be readily trained to distinguish between different shapes and patterns. They have been reported to practice observational learning, although the validity of these findings is widely contested on a number of grounds. Octopuses have also been observed in what some have described as play: repeatedly releasing bottles or toys into a circular current in their aquariums and then catching them. Octopuses often break out of their aquariums and sometimes into others in search of food. They have even boarded fishing boats and opened holds to eat crabs.
In some countries, octopuses are on the list of experimental animals on which surgery may not be performed without anesthesia. In the UK, cephalopods such as octopuses are regarded as honorary vertebrates under the Animals (Scientific Procedures) Act 1986 and other cruelty to animals legislation, extending to them protections not normally afforded to invertebrates.
The octopus is the only invertebrate which has been conclusively shown to use tools. At least four specimens of the Veined Octopus (Amphioctopus marginatus) have been witnessed retrieving discarded coconut shells, manipulating them, and then reassembling them to use as shelter. This discovery was documented in the journal Current Biology and has also been caught on video.
Defense

Greater Blue-ringed Octopus (Hapalochlaena lunulata)
An octopus's main (primary) defense is to hide, either not to be seen at all, or not to be detected as an octopus. Octopuses have several secondary defenses (defenses they use once they have been seen by a predator). The most common secondary defense is fast escape. Other defenses include the use of ink sacs, camouflage, and autotomising limbs.
Most octopuses can eject a thick blackish ink in a large cloud to aid in escaping from predators. The main colouring agent of the ink is melanin, which is the same chemical that gives humans their hair and skin colour. This ink cloud is thought to reduce the efficiency of olfactory organs, which would aid an octopus's evasion from predators that employ smell for hunting, such as sharks. Ink clouds of some species might serve as pseudomorphs, or decoys that the predator attacks instead.

Amphioctopus marginatus travels with shells it has collected for protection
An octopus's camouflage is aided by certain specialized skin cells which can change the apparent color, opacity, and reflectiveness of the epidermis. Chromatophores contain yellow, orange, red, brown, or black pigments; most species have three of these colors, while some have two or four. Other color-changing cells are reflective iridophores, and leucophores (white). This color-changing ability can also be used to communicate with or warn other octopuses. The very venomous blue-ringed octopus becomes bright yellow with blue rings when it is provoked. Octopuses can use muscles in the skin to change the texture of their mantle to achieve a greater camouflage. In some species the mantle can take on the spiky appearance of seaweed, or the scraggly, bumpy texture of a rock, among other disguises. However in some species skin anatomy is limited to relatively patternless shades of one color, and limited skin texture. It is thought that octopuses that are day-active and/or live in complex habitats such as coral reefs have evolved more complex skin than their nocturnal and/or sand-dwelling relatives.
When under attack, some octopuses can perform arm autotomy, in a similar manner to the way skinks and other lizards detach their tails. The crawling arm serves as a distraction to would-be predators.
A few species, such as the Mimic Octopus, have a fourth defense mechanism. They can combine their highly flexible bodies with their color changing ability to accurately mimic other, more dangerous animals such as lionfish, sea snakes, and eels.
Reproduction
When octopuses reproduce, males use a specialized arm called a hectocotylus to insert spermatophores (packets of sperm) into the female's mantle cavity. The hectocotylus in benthic octopuses is usually the third right arm. Males die within a few months of mating. In some species, the female octopus can keep the sperm alive inside her for weeks until her eggs are mature. After they have been fertilized, the female lays about 200,000 eggs (this figure dramatically varies between families, genera, species and also individuals). The female hangs these eggs in strings from the ceiling of her lair, or individually attaches them to the substrate depending on the species. The female cares for the eggs, guarding them against predators, and gently blowing currents of water over them so that they get enough oxygen. The female does not hunt during the roughly one-month period spent taking care of the unhatched eggs and may ingest some of her own arms for sustenance. At around the time the eggs hatch, the mother leaves the lair and is too weak to defend herself from predators like cod, often succumbing to their attacks. The young larval octopuses spend a period of time drifting in clouds of plankton, where they feed on copepods, larval crabs and larval starfish until they are ready to descend to the ocean bottom, where the cycle repeats. This is a dangerous time for the larval octopuses; in the plankton cloud they are vulnerable to plankton eaters. In some deeper dwelling species, the young do not go through this period.
Sensation
Eye of Octopus vulgaris
Octopuses have keen eyesight. Octopuses, like other cephalopods, can distinguish the polarization of light. Color vision appears to vary from species to species, being present in Octopus aegina but absent in Octopus vulgaris. Attached to the brain are two special organs, called statocysts, that allow the octopus to sense the orientation of its body relative to horizontal. An autonomic response keeps the octopus's eyes oriented so that the pupil slit is always horizontal.
Octopuses also have an excellent sense of touch. An octopus's suction cups are equipped with chemoreceptors so that the octopus can taste what it is touching. The arms contain tension sensors so that the octopus knows whether its arms are stretched out. However, the octopus has a very poor proprioceptive sense. The tension receptors are not sufficient for the octopus brain to determine the position of the octopus's body or arms. (It is not clear that the octopus brain would be capable of processing the large amount of information that this would require; the flexibility of an octopus's arms is much greater than that of the limbs of vertebrates, which devote large areas of cerebral cortex to the processing of proprioceptive inputs.) As a result, the octopus does not possess stereognosis; that is, it does not form a mental image of the overall shape of the object it is handling. It can detect local texture variations, but cannot integrate the information into a larger picture.
The neurological autonomy of the arms means that the octopus has great difficulty learning about the detailed effects of its motions. The brain may issue a high-level command to the arms, but the nerve cords in the arms execute the details. There is no neurological path for the brain to receive feedback about just how its command was executed by the arms; the only way it knows just what motions were made is by observing the arms visually.
Octopuses appear to have limited hearing.

Octopuses swim headfirst, with arms trailing behind
Locomotion
Octopuses move about by crawling or swimming. Their main means of slow travel is crawling, with some swimming. Jet propulsion is their fastest means of locomotion, followed by swimming and walking.
They crawl by walking on their arms, usually on many at once, on both solid and soft surfaces, while supported in water. In 2005 it was reported that some octopuses (Adopus aculeatus and Amphioctopus marginatus under current taxonomy) can walk on two arms, while at the same time resembling plant matter. This form of locomotion allows these octopuses to move quickly away from a potential predator while possibly not triggering that predator's search image for octopus (food).
Octopuses swim by expelling a jet of water from a contractile mantle, and aiming it via a muscular siphon.
Size
An adult North Pacific Giant Octopus, Enteroctopus dofleini
The North Pacific Giant Octopus, Enteroctopus dofleini, is often cited as the largest octopus species. Adults usually weigh around 15 kg (33 lb), with an arm span of up to 4.3 m (14 ft). The largest specimen of this species to be scientifically documented was an animal with a live mass of 71 kg (156.5 lb). The alternative contender is the Seven-arm Octopus, Haliphron atlanticus, based on a 61 kg (134 lb) carcass estimated to have a live mass of 75 kg (165 lb). However, there are a number of questionable size records that would suggest E. dofleini is the largest of all octopus species by a considerable margin; one such record is of a specimen weighing 272 kg (600 lb) and having an arm span of 9 m (30 ft).
Terminology
The term octopus, pronounced /ˈɒktəpʊs/, is from Greek ὀκτάπους (oktapous), "eight-footed", with plural forms: octopuses /ˈɒktəpʊsɪz/, octopi /ˈɒktəpaɪ/, or octopodes /ɒkˈtɒpədiːz/. Currently, octopuses is the most common form in both the US and the UK; octopodes is rare, and octopi is often objectionable.
The plural form octopi is often defined as a hypercorrection. The Oxford English Dictionary (2008 Draft Revision) lists octopuses, octopi and octopodes (in that order); it labels octopodes "rare", and notes that octopi derives from the "apprehension" that octōpūs is a second declension Latin noun, though it is not. It is a Latinization of Greek third-declension masculine oktṓpous (ὀκτώπους, 'eight-foot'), plural oktṓpodes (ὀκτώποδες). If the word were native to Latin, it would be octōpēs, plural octōpedes, after the pattern of pēs ('foot'), plural pedēs, analogous to "centipede". The actual Latin word for octopus and other similar species is polypus, from Greek polýpous (πολύπους, 'many-foot'); usually the inaccurate plural polypī is used instead of polypodēs.
In modern Greek, the word is khtapódi (χταπόδι), plural khtapódia (χταπόδια), from Medieval oktapódion (ὀκταπόδιον), equivalent to Classical oktápous (ὀκτάπους), variant of oktṓpous.
Chambers 21st Century Dictionary and the Compact Oxford Dictionary list only octopuses, although the latter notes that octopodes is "still occasionally used"; the British National Corpus has 29 instances of octopuses, 11 of octopi and 4 of octopodes. Merriam-Webster 11th Collegiate Dictionary lists octopuses and octopi, in that order; Webster's New World College Dictionary lists octopuses, octopi and octopodes (in that order).
Fowler's Modern English Usage states that "the only acceptable plural in English is octopuses," and that octopi is misconceived and octopodes pedantic.
The term octopod (plural octopods or octopodes) is taken from the taxonomic order Octopoda but has no classical equivalent. The collective form octopus is usually reserved for animals consumed for food.
Relationship to humans
Left: Vase from a Mycenaean Greek cemetery at Prosymna, Argos, grave 2, c. 1500 BCE
Centre: Moche Octopus (200 AD), Larco Museum Collection, Lima, Peru
Right: Ancient Greek black-figure amphora, 530–520 BC. On the left, a hoplite with an octopus image on his shield. Staatliche Antikensammlungen, Munich, Germany
Ancient peoples of the Mediterranean were aware of the octopus, as evidenced by certain artworks and designs of prehistory. For example, a stone carving found in the archaeological recovery from Bronze Age Minoan Crete at Knossos has a depiction of a fisherman carrying an octopus.
Octopuses were often depicted in the art of the Moche people of ancient Peru, who worshipped the sea and its animals.
In mythology
The Hawaiian creation myth relates that the present cosmos is only the last of a series, having arisen in stages from the wreck of the previous universe. In this account, the octopus is the lone survivor of the previous, alien universe.
In literature
The octopus has a significant role in Victor Hugo's book Travailleurs de la mer (Toilers of the Sea).
Octopus at Tsukiji fish market
As food
Humans eat octopus in many cultures. The arms and sometimes other body parts are prepared in various ways, often varying by species.
Octopus is a common ingredient in Japanese cuisine, including sushi, takoyaki, and Akashiyaki. Some small species are sometimes eaten alive as a novelty food. Similarly, a live octopus may be sliced up and the legs eaten while still squirming, which continues for some minutes.

Octopuses are "tickled" out of their holes‎ in the Hawaiian Islands with 3-pronged polespears
Octopus is eaten regularly in Hawaii, since many popular dishes are Asian in origin. Locally known by their Hawaiian or Japanese names ("he'e" and "tako" respectively), octopus is also a popular fish bait.
Octopus is a common food in Mediterranean cuisine and Portuguese cuisine. In Galicia, polbo á feira (market fair style octopus) is a local delicacy. Restaurants which specialize or serve this dish are known as pulperías. On the Tunisian island of Djerba, local people catch octopuses by taking advantage of the animals' habit of hiding in safe places during the night. In the evening they put grey ceramic pots on the sea bed. The morning of the following day they check them for octopuses that sheltered there. A common scene in the Greek islands is octopuses hanging in the sunlight from a rope, just like laundry from a clothesline. They are often caught by spear fishing close to the shore. The fisherman brings his prey to land and tenderizes the flesh by pounding the carcass against a stone surface. Thus treated they are hung out to dry, and later will be served grilled either hot, or chilled in a salad.
According to the USDA Nutrient Database (2007), cooked octopus contains approximately 139 calories per three ounce portion, and is a source of vitamin B3, B12, potassium, phosphorus, and selenium.
Care must be taken to boil the octopus properly, to rid it of slime, smell, and residual ink.
As pets
Though octopuses can be difficult to keep in captivity, some people keep them as pets. Octopuses often escape even from supposedly secure tanks, due to their problem-solving skills, mobility and lack of rigid structure.
The variation in size and life span among octopus species makes it difficult to know how long a new specimen can naturally be expected to live. That is, a small octopus may be just born or may be an adult, depending on its species. By selecting a well-known species, such as the California Two-spot Octopus, one can choose a small octopus (around the size of a tennis ball) and be confident that it is young with a full life ahead of it.
Octopuses are also quite strong for their size. Octopuses kept as pets have been known to open the covers of their aquariums and survive for a time in the air in order to get to a nearby feeder tank and gorge themselves on the fish there. They have also been known to catch and kill some species of sharks.

THE BERMUDA TRIANGLES

2010-07-07T12:07:00.000-07:00

THE BERMUDA TRIANGLES

The Site
This site is a compilation of data from 1492 to 2001 on over 170 disappearances of ships, boats, planes and other phenomena which have occurred in or near (sometimes far from!) the area known as "The Bermuda Triangle".
The number of discrepancies in the documentation is astounding. Some of the disappearances occurred far from the boundaries of the triangle, some occurred in very bad storms and rough seas, some have other factors which might be responsible, some have no facts that can be verified, but there are a few that are quite strange.
The Area
The "Bermuda or Devil's Triangle" is an imaginary area located off the southeastern Atlantic coast of the United States, which is noted for a high incidence of unexplained losses of ships, small boats, and aircraft. The apexes of the triangle are generally accepted to be Bermuda, Miami, Fla., and San Juan, Puerto Rico. However, The U. S. Board of Geographic Names does not recognize the Bermuda Triangle as an official name and does not maintain an official file on the area.
An area called the "Devil's Sea" by Japanese and Filipino seamen, located off the east coast of Japan, also exhibits the same magnetic characteristics. It is also known for its mysterious disappearances.
Brief History
To my knowledge the first documentation that anything was amiss in the area came from Christopher Columbus,
who reported compass malfunctions and a bolt of fire that fell into the sea. He also reports of a light on the horizon.
The rest is history.... sort of.
Since that time there have been hundreds of disappearances in the area. A full time job for the Coast Guard no doubt.
In the past, extensive, but futile Coast Guard searches prompted by search and rescue cases such as the disappearances of an entire squadron of TBM Avengers (Flight 19) shortly after take off from Fort Lauderdale, Fla., or the traceless sinking of USS CYCLOPS and MARINE SULPHUR QUEEN have lent credence to the popular belief in the mystery and the supernatural qualities of the "Bermuda Triangle."

It seems that interest in the "Bermuda Triangle" can be traced to (1) the cover article in the August 1968 Argosy, "The Spreading Mystery of the Bermuda Triangle", (2) the answer to a letter to the editor of the January 1969 Playboy and (3) an article in August 4, 1968 I, "Limbo of Lost Ships", by Leslie Lieber. Also, many newspapers carried a December 22, 1967 National Geographic Society news release which was derived largely from Vincent Gaddis' Invisible Horizons: True Mysteries of the Sea (Chilton Books, Philadelphia, 1965. OCLC# 681276) Chapter 13, "The Triangle of Death", in Mr. Gaddis' book, presents the most comprehensive account of the mysteries of the Bermuda Triangle. Gaddis describes nine of the more intriguing mysteries and provides copious notes and references. Much of the chapter is reprinted from an article by Mr. Gaddis, "The Deadly Bermuda Triangle", in the February 1964 Argosy. The article elicited a large and enthusiastic response from the magazine's readers. Perhaps the most interesting letter, which appeared in the May 1964 of Argosy's "Back Talk" section, recounts a mysterious and frightening incident in an aircraft flying over the area in 1944.
Theories

Countless theories attempting to explain the many disappearances have been offered throughout the history of the area. The most practical seem to be environmental and those citing human error. The majority of disappearances can be attributed to the area's unique environmental features.
It has been said that the "Devil's Triangle" is one of the two places on earth that a magnetic compass does point towards true north. Normally it points toward magnetic north. The difference between the two is known as compass variation. The amount of variation changes by as much as 20 degrees as one circumnavigates the earth. If this is the case and a compass variation or error is not compensated for, a navigator could find himself far off course and in deep trouble.

Another environmental factor is the character of the Gulf Stream. It is extremely swift and turbulent and can quickly erase any evidence of a disaster. The unpredictable Caribbean-Atlantic weather pattern also plays its role. Sudden local thunder storms and water spouts often spell disaster for pilots and mariners. Finally, the topography of the ocean floor varies from extensive shoals around the islands to some of the deepest marine trenches in the world. With the interaction of the strong currents over the many reefs the topography is in a state of constant flux and development of new navigational hazards is swift. Not to be under estimated is the human error factor. A large number of pleasure boats travel the waters between Florida's Gold Coast and the Bahamas. All too often, crossings are attempted with too small a boat, insufficient knowledge of the area's hazards, and a lack of good seamanship.
gas
Dr. Ben Clennell, of Leeds University, England, is not the first to make note of the possibility of methane hydrates as a source for causing ships to disappear, he has become identified with the theory which, on September 21, 1998, at the Festival of Earth Sciences at Cardiff, Wales, he proposed methane hydrates as the future of energy.
As a part of his elaborate dissertation he claimed that methane locked below the sea sediments in the Bermuda Triangle can explain the mysterious disappearances. He told how subterranean landslides can unlock the vast beds of methane hydrate. This would be disastrous, he told the audience, because large amounts of methane would reduce the density of the water. “This would make any ship floating above sink like a rock.” He went on to explain how the highly combustible gas could also ignite aircraft engines and blow them to pieces. Although I believe a certain percentage of flammable gas to air is required for the atmosphere to become combustible.
aliens and time
There is another school of thought regarding the disappearance of people along with their craft, it is thought that they are "trapped in-between time dimensions," of which there is "no way out." These disappearances are accidental and not intentional. The victims were in the wrong place, at the wrong time.
The "Bermuda Triangle" is one of two portals, used by the "human-like" aliens, to travel from their planet to ours. The "Bermuda Triangle" is not actually a triangle. When it is "in-phase," it is constantly in motion and in intensity (between one to one and a half mile wide). The disappearances occur when caught in the center or within the first two outward radiating rings.
The occurrence takes place 25 times a year and lasts for 28 minutes, for the "Bermuda Triangle." The "Pacific Triangle," takes place only 3 times a year. The "Bermuda and the Pacific Triangles" are linked to other triangles that exist throughout the universe. The "human-like" aliens technology enable them to use "time compression, solar power and the ability to reduce friction," for travelling across vast distances. It takes them approximately 24 hours to travel from their planet to Earth.
These "time holes" can be described as an "accordion in motion." When the "time hole" is compressed, the craft enters one end and when the "time hole" expands itself, the craft is at the opposite end exiting one "time hole" and entering another. The "human-like" aliens know exactly which "time hole" is compressed, at any given time.
atlantis & crystals
This theory was helped along in more recent years by the psychic Edgar Cayce (1877-1945) who became the U.S.'s most prominent advocate of a factual Atlantis. Widely known as "The Sleeping Prophet," Cayce claimed the ability to see the future and to communicate with long-dead spirits from the past. He identified hundreds of people...including himself ...as reincarnated Atlanteans.
Cayce said that Atlantis had been situated near the Bermuda island of Bimini. He believed that Atlanteans possessed remarkable technologies, including supremely powerful "fire-crystals" which they harnessed for energy. A disaster in which the fire-crystals went out of control was responsible for Atlantis's sinking, he said, in what sounds very much like a cautionary fable (what is that about history repeating itself ?) on the dangers of nuclear power. If still intermitently active beneath the ocean waves, damaged fire-crystals send out energy fields that interfere with passing ships and aircraft...which is how Cayce accounted for the Bermuda Triangle.
Cayce prophesied that "elements of Atlantis would rise in 1968 and 1969". The Bimini Wall or Road was discovered off the coast of Bimini in 1968.
ray brown's crystal
In 1970, Dr. Ray Brown, a naturopathic practitioner from Mesa, Arizona, went scuba diving with some friends near the Bari Islands in the Bahamas, close to a popular area known as the Tongue of the Ocean (This was depicted in the television show, "In Search Of...Atlantis," originally made in 1979.
During one of his dives, Brown became separated from his friends and while searching for them he was startled when he came across a strange pyramid shape silhouetted against the aquamarine light. Upon investigating further, Brown was surprised by how smooth and mirror-like was the stone surface of the whole structure, with the joints between the individual blocks almost indiscernible. Swimming around the capstone, which Brown thought might have been lapis lazuli, he discovered an entrance and decided to explore inside. Passing along a narrow hallway, Brown finally came to a small rectangular room with a pyramid-shaped ceiling. He was totally amazed that this room contained no algae or coral growing on the inner walls. They were completely spotless! In addition, though Brown had brought no torch with him, he could nevertheless see everything in the room with his normal eyesight. The room was well lit, but no direct light source was visible. Brown's attention was drawn to a brassy metallic rod three inches in diameter hanging down from the apex of the center of the room and at its end was attached a many-facetted red gem, which tapered to a point. Directly below this rod and gem, sitting in the middle of the room, was a stand of carved stone topped by a stone plate with scrolled ends. On the plate there was a pair of carved metal bronze-colored hands, life-sized, which appeared blackened and burnt, as if having been subjected to tremendous heat. Nestled in the hands, and situated four feet directly below the ceiling rod gem point, was a crystal sphere four-inches in diameter. Brown tried to loosen the ceiling rod and red gemstone but neither would move. Returning to the crystal sphere, he found, to his amazement, that it separated easily from the bronze hand holders. With the crystal sphere in his right hand he then made his way out of the pyramid. As he departed, Brown felt an unseen presence and heard a voice telling him never to return!
Fearing, rightly, that his unusual prize might be confiscated as salvage-treasure by the American Government, Dr. Brown did not reveal the existence of his strange crystal sphere, nor did he relate his experiences until 1975, when he exhibited his crystal for the first time at a psychic seminar in Phoenix.
Since that time, the crystal sphere has made only a very few public appearances but on each occasion people who have seen it have experienced strange phenomena directly associated with it.
Deep inside the crystal form, one gazes upon three pyramidal images, one in front of the other,in decreasing sizes. Some people who enter a deep meditative state of consciousness are able to discern a fourth pyramid, in the foreground of the other three.
Elizabeth Bacon, a New York psychic, claimed while in trance, that the crystal sphere had once belonged to Thoth, the Egyptian God who was responsible for burying a secret vault of knowledge in Giza, near the three great Pyramids. Perhaps the positions of the three pyramidal images in the crystal sphere hold the long-sought key to finding a fourth, as yet unfound, subterranean pyramid that will lead us to the Hall of Records? Who knows?
Looking at the crystal sphere from the side, the internal images dissolve into thousands of tiny fracture lines. Brown feels that these may prove to be electrical in nature, like some form of microscopic circuitry. From yet another angle, and under special conditions, many people have been able to see a large single human eye staring out serenely at them. Photographs of this eye have also been taken. I have not been able to find this photo anywhere.
Dr. Brown's crystal sphere has been the source of a wide variety of paranormal and mysterious occurrences. People have felt breezes or winds blowing close to it. Both cold and warm layers surround it at various distances. Other witnesses have observed phantom lights, heard voices or felt strange tingling sensations surrounding it. A compass needle, when placed next to the crystal sphere, will spin counter-clockwise, then commence turning in the opposite direction when moved only inches away. Metals become temporarily magnetized when they come into close contact with the sphere.
There are even recorded instances where healing has taken place by merely touching the sphere.
We may only speculate as to why the crystal sphere was created and what part it once played within the underwater Bahamas pyramid discovered by Ray Brown.
Disappearances and other strange occurrences in the area are contained in links listed in the table below,
listed by dates. The books listed give sources and references except where noted.
1492 to 1900
1901 to 1925
1926 to 1950
1951 to 1975
1976 to Date

THE GREAT WALL OF CHINA

2010-07-06T13:03:00.000-07:00

THE GREAT WALL OF CHINA

The Great Wall of China is actually a series of walls built over the course of approximately 2000 years. The wall was built by a succession of Chinese Emperors and rulers as a military fortification to protect against encroaching enemies. It began by connecting smaller fortifications built by earlier leaders. How long is the Great Wall of China? That number is up for debate. Some historians put the length of the Great Wall at anywhere between 1,500 and 2,600 miles, spanning from western Jiayuguan, past the Gobi Desert, over the Yellow River, past Beijing and through to Shanhaiguan on the Bohai Sea. If you ask other historians how long is the Great Wall of China, they may tell you that the length of the Wall is actually closer to 4,000 miles. From its lowest point in the desert, parts of the wall reached heights of over 6,000 feet. Today, fragments of the Wall in various states of disrepair line the countryside of northern China.
The History of the Great Wall of China
The history of the Great Wall of China is as bloody and gruesome as the history of ancient Chinese civilization itself. Construction of the Wall began in the third century B.C. when the first Emperor of China, Qin Shih Huang Di engaged in a bloody battle and ultimately succeeded in uniting what was known as “the Warring States.” For the first time, China was unified. But with enemies all around, particularly the Mongols encroaching from the North, Emperor Qin set about to strengthen his defenses. He gathered a work force consisting of 200,000 convicts and 100,000 soldiers and commissioned them to build a barrier that would thwart all enemies. It took 10 years to construct this wall, often referred to as the first Great Wall of China. During this time, thousands of workers would die from exposure to the elements and fatigue. Others died from enemy military action that cropped up during the building of the wall. And still other workers were put to death at the end of the construction project so as not to reveal secrets of the construction itself. In fact according to the history of the Great Wall of China, so many workers were said to have died during its building, that it is often referred to as “the longest cemetery on Earth” or the “longest graveyard.”
One famous myth about the building of the Great Wall involved Chinese wife Meng Chiang-nu, whose husband had been called to work on the Wall. After he had been gone a long time, she went searching for him. Unable to find him and overcome with grief, the legend goes that her tears were so bitter and copious that the Great Wall opened up and surrendered the body of her beloved husband.
Work on the Great Wall Continues
Although the Great Wall of China was conceived and started during the reign of Emperor Qin, the Wall that exists today for tourists to see was primarily built during later periods. During the first century B.C.E., the third century C.E., the Han and Sui Dynasties respectively sent men to expand the breadth of the Great Wall. And in the twelfth century, during a period in Chinese History called 10 Kingdoms, the Great Wall construction on the Great Wall continued. The construction during all these periods, including the first building of the Great Wall during the Qin period was done in a similar manner using packed earth to form the wall and interspersing tall watch towers along the Wall so the kingdoms could see marauders invading from a distance. The portion of the Wall that is most visited today was built by the Ming Dynasty in the middle ages, during the years 1368 through 1644. The Ming Dynasty built its portion using stronger materials such as brick and stone. This is why today, in Chinese cities like Beijing, tourists are able to see parts of the Great Wall that are largely intact. Although invaders such as the Mongols and the Manchus were able to take control of China during the Ming Dynasty, it is said that no foreign enemy ever breached the Wall. Every successful invasion was due to a breakdown in the government and political weakness and not the weakness of the Great Wall itself. The Wall was made a UNESCO World Heritage Site in 1987 and is currently the subject of a restoration effort by the Chinese government.

GREAT PYRAMID OF GIZA

2010-07-02T12:50:00.000-07:00

Great Pyramid of Giza

The Great Pyramid of Giza, in 2005. Built c. 2560 BC, it is the oldest and largest of the three pyramids in the Giza Necropolis.
The Great Pyramid of Giza (also called the Pyramid of Khufu and the Pyramid of Cheops) is the oldest and largest of the three pyramids in the Giza Necropolis bordering what is now El Giza, Egypt. It is the oldest of the Seven Wonders of the Ancient World, and the only one to remain largely intact. It is believed the pyramid was built as a tomb for fourth dynasty Egyptian Pharaoh Khufu (Cheops in Greek) and constructed over a 20-year period concluding around 2560 BC. The Great Pyramid was the tallest man-made structure in the world for over 3,800 years. Originally the Great Pyramid was covered by casing stones that formed a smooth outer surface; what is seen today is the underlying core structure. Some of the casing stones that once covered the structure can still be seen around the base. There have been varying scientific and alternative theories about the Great Pyramid's construction techniques. Most accepted construction hypotheses are based on the idea that it was built by moving huge stones from a quarry and dragging and lifting them into place.
There are three known chambers inside the Great Pyramid. The lowest chamber is cut into the bedrock upon which the pyramid was built and was unfinished. The so-called Queen's Chamber and King's Chamber are higher up within the pyramid structure. The Great Pyramid of Giza is the only pyramid in Egypt known to contain both ascending and descending passages. The main part of the Giza complex is a setting of buildings that included two mortuary temples in honor of Khufu (one close to the pyramid and one near the Nile), three smaller pyramids for Khufu's wives, an even smaller "satellite" pyramid, a raised causeway connecting the two temples, and small mastaba tombs surrounding the pyramid for nobles.
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Building of the Great pyramid of Giza
It is believed the pyramid was built as a tomb for Fourth dynasty Egyptian pharaoh Khufu and constructed over a 14 to 20 year period. Khufu's vizier, Hemon, or Hemiunu, is believed by some to be the architect of the Great Pyramid. It is thought that, at construction, the Great Pyramid was originally 280 Egyptian cubits tall, 146.478 metres (480.57 ft) but with erosion and absence of its pyramidion, its present height is 138.75 metres (455.22 ft). Each base side was 440 royal cubits, 230.37 metres (755.81 ft) long. A royal cubit measures 0.524 metres. The mass of the pyramid is estimated at 5.9 million tonnes. The volume, including an internal hillock, is roughly 2,500,000 cubic meters. Based on these estimates, building this in 20 years would involve installing approximately 800 tonnes of stone every day. Alternatively looking at the construction from another angle, since the Great Pyramid consists of an estimated 2.3 million blocks, completing the building in 20 years would involve moving little more than 12 of the blocks in place each hour, day and night, during the 20 year period. The first precision measurements of the pyramid were done by Egyptologist Sir Flinders Petrie in 1880–82 and published as The Pyramids and Temples of Gizeh. Almost all reports are based on his measurements. Many of the casing stones and inner chamber blocks of the Great Pyramid were fit together with extremely high precision. Based on measurements taken on the north eastern casing stones, the mean opening of the joints are only 0.5 millimeters wide (1/50th of an inch).

Great Pyramid of Giza from a 19th century stereopticon card photo
The pyramid remained the tallest man-made structure in the world for over 3,800 years, unsurpassed until the 160-meter-tall spire of Lincoln Cathedral was completed c. 1300. The accuracy of the pyramid's workmanship is such that the four sides of the base have an average error of only 58 millimeters long The base is horizontal and flat to within 21 mm[10]. The sides of the square base are closely aligned to the four cardinal compass points (within 4 minutes of arc) based on true north, not magnetic north, and the finished base was squared to a mean corner error of only 12 seconds of arc. The completed design dimensions, as suggested by Petrie's survey and subsequent studies, are estimated to have originally been 280 cubits high by 440 cubits long at each of the four sides of its base. These proportions equate to π/2 to an accuracy of better than 0.05% (corresponding to the approximation of π as 22/7). Some Egyptologists consider this to have been the result of deliberate design proportion.Verner wrote, "We can conclude that although the ancient Egyptians could not precisely define the value of π, in practice they used it". Petrie, author of Pyramids and Temples of Gizeh, who was the first accurate surveyor of Giza and the excavator and surveyor of the Pyramid of Meidum, concluded: "but these relations of areas and of circular ratio are so systematic that we should grant that they were in the builders design". Earlier in the chapter he wrote more specifically, that: “We conclude therefore that the approximation of 7 to 22 as the ratio of diameter to circumference was recognised”. These proportions equated to the four outer faces sloping by 51.843° or 51° 50′ 34″, which would have been understood and expressed by the Ancient Egyptians as a seked slope of 5½ palms.
Materials
The Great Pyramid consists of an estimated 2.3 million limestone blocks with most believed to have been transported from nearby quarries. The Tura limestone used for the casing was quarried across the river. The largest granite stones in the pyramid, found in the "King's" chamber, weigh 25 to 80 tonnes and were transported more than 500 miles away from Aswan. Traditionally, ancient Egyptians cut stone blocks by hammering wooden wedges into the stone which were then soaked with water. As the water was absorbed, the wedges expanded, causing the rock to crack. Once they were cut, they were carried by boat either up or down the Nile River to the pyramid.
Casing stones

casing stone
At completion, the Great Pyramid was surfaced by white 'casing stones' – slant-faced, but flat-topped, blocks of highly polished white limestone. These were carefully cut to what is approximately a face slope with a seked of 5½ palms to give the required dimensions. Visibly, all that remains is the underlying stepped core structure seen today. In AD 1300, a massive earthquake loosened many of the outer casing stones, which were then carted away by Bahri Sultan An-Nasir Nasir-ad-Din al-Hasan in 1356 to build mosques and fortresses in nearby Cairo. The stones can still be seen as parts of these structures to this day. Later explorers reported massive piles of rubble at the base of the pyramids left over from the continuing collapse of the casing stones, which were subsequently cleared away during continuing excavations of the site. Nevertheless, a few of the casing stones from the lowest course can be seen to this day in situ around the base of the Great Pyramid, and display the same workmanship and precision as has been reported for centuries. Petrie also found a different orientation in the core and in the casing measuring 193 centimeters ± 25 centimeters. He suggested a redetermination of north was made after the construction of the core, but a mistake was made, and the casing was built with a different orientation. Petrie related the precision of the casing stones as to being "equal to opticians' work of the present day, but on a scale of acres." and "to place such stones in exact contact would be careful work; but to do so with cement in the joints seems almost impossible."
Construction theories
Main article: Egyptian pyramid construction techniques
Many alternative, often contradictory, theories have been proposed regarding the Pyramid's construction techniques. Not all even agree that the blocks were quarried; Davidovits claims that they were cast in situ using a "limestone concrete", a theory which is rejected by other Egyptologists. The rest accept that it was built by moving huge stones from a quarry, being only unable to agree whether they were dragged, lifted or even rolled into place. The Greeks believed that slave labour was used, but modern Egyptologists accept that it was built by many tens of thousands of skilled workers. They camped near the pyramids and worked for a salary or as a form of paying taxes until the construction was completed. Their cemeteries were discovered in 1990 by archaeologists Zahi Hawass and Mark Lehner. Verner posited that the labor was organized into a hierarchy, consisting of two gangs of 100,000 men, divided into five zaa or phyle of 20,000 men each, which may have been further divided according to the skills of the workers.
One mystery of the pyramid's construction is its planning. John Romer suggests that they used the same method that had been used for earlier and later constructions, laying out parts of the plan on the ground at a 1 to 1 scale. He writes that "such a working diagram would also serve to generate the architecture of the pyramid with precision unmatched by any other means." He devotes a chapter of his book to the physical evidence that there was such a plan. The 1925 Cole survey discovered as part of some planning an actual Original Builder's Mark, engraved into the pavement perpendicular to the N face.
Interior

Diagram of the interior structures of the Great Pyramid. The inner line indicates the pyramid's present profile, the outer line indicates the original profile.
The original entrance to the Great Pyramid is 17m (55’7”) vertically above ground level and 7.29m (23'11”) east of the center line of the pyramid. From this original entrance there is a Descending Passage 0.96m (3'2") high and 1.04m (3'5") wide which goes down at an angle of 26° 31'23" through the masonry of the pyramid and then into the bedrock beneath it. After 105.23m (345’3”) the passage becomes level and continues for an additional 8.84m (29’) to the lower Chamber, which appears not to have been finished. There is a continuation of the horizontal passage in the south wall of the lower chamber; there is also a pit dug in the floor of the chamber. Some Egyptologists suggest this Lower Chamber was intended to be the original burial chamber, but that King Khufu later changed his mind and wanted it to be higher up in the pyramid.
28.2m (98’7”) from the entrance is a square hole in the roof of the Descending Passage. Originally concealed with a slab of stone, this is the beginning of the Ascending Passage. The Ascending Passage is 39.3m (129') long, as wide and high as the Descending Passage and slopes up at almost precisely the same angle. The lower end the Ascending Passage is closed by three huge blocks of granite, each about 1.5m (5') long. At the start of the Grand Gallery on the right-hand side there is a hole cut in the wall (and now blocked by chicken wire). This is the start of a vertical shaft which follows an irregular path through the masonry of the pyramid to join the Descending Passage. Also at the start of the Grand Gallery there is a Horizontal Passage leading to the "Queen's Chamber". The passage is 1.1m (3'8") high for most of its length, but near the chamber there is a step in the floor, after which the passage is 1.73m (5'8") high.
The Queen's Chamber is exactly half-way between the north and south faces of the pyramid and measures 5.75m (18'10") north to south, 5.23m (17'2") east to west and has a pointed roof with an apex 6.23m (20'5") above the floor. At the eastern end of the chamber there is a niche 4.67m (15'4") high. The original depth of the niche was 1.04m (3'5"), but has since been deepened by treasure hunters.
In the north and south walls of the Queen's Chamber there are shafts, which unlike those in the King's Chamber that immediately slope upwards, are horizontal for around 2m (6') before sloping upwards. The horizontal distance was cut in 1872 by a British engineer, Waynman Dixon, who believed on the analogy of the King's Chamber that such shafts must exist. He was proved right, but because the shafts are not connected to the outer faces of the pyramid or the Queen's Chamber, their purpose is unknown. At the end of one of his shafts, Dixon discovered a ball of black diorite and a bronze implement of unknown purpose. Both objects are currently in the British Museum.
The shafts in the Queen's Chamber were explored in 1992 by the German engineer Rudolf Gantenbrink using a crawler robot of his own design which he called "Upuaut 2". He discovered that one of the shafts was blocked by limestone "doors" with two eroded copper "handles". Some years later the National Geographic Society created a similar robot which drilled a small hole in the southern door, only to find another larger door behind it. The northern passage, which was difficult to navigate because of twists and turns, was also found to be blocked by a door.
The Grand Gallery continues the slope of the Ascending Passage, but is 8.6m (28') high and 46.68m (153') long. At the base it is 2.06m (6'9") wide, but after 2.29m (7'6") the blocks of stone in the walls are corbelled inwards by 7.6 cm (3") on each side. There are seven of these steps, so at the top the Grand Gallery is only 1.04m (3'5") wide. It is roofed by slabs of stone laid at a slightly steeper angle than the floor of the gallery, so that each stone fits into a slot cut in the top of the gallery like the teeth of a ratchet. The purpose was to have each block supported by the wall of the Gallery rather than resting on the block beneath it, which would have resulted in an unacceptable cumulative pressure at the lower end of the Gallery.
At the upper end of the Gallery on the right-hand side there is a hole near the roof which opens into a short tunnel by which access can be gained to the lowest of the Relieving Chambers. The other Reliving Chambers were discovered in 1837/8 by Colonel Howard Vyse and J. S. Perring, who dug tunnels upwards using blasting powder.
The floor of the Grand Gallery consists of a shelf or step on either side, 51 cm (1'8") wide, leaving a lower ramp 1.04m (3'5") wide between them. In the shelves there are 54 slots, 27 on each side matched by vertical and horizontal slots in the walls of the Gallery. These form a cross shape that rises out of the slot in the shelf. The purpose of these slots is not known, but the central gutter in the floor of the Gallery, which is the same width as the Ascending Passage, has led to speculation that the blocking stones were stored in the Grand Gallery and the slots held wooden beams to restrain them from sliding down the passage. This, in turn, has led to the proposal that originally many more than 3 blocking stones were intended, to completely fill the Ascending Passage.At the top of the Grand Gallery there is a step giving onto a horizontal passage approximately 1.02m (3'4") long, in which can be detected four slots, three of which were probably intended to hold granite portcullises. Fragments of granite found by Petrie in the Descending Passage may have come from these now vanished doors.
The King's Chamber is 10.47m (34'4") from east to west and 5.234m (17'2") north to south. It has a flat roof 5.974m (19'1") above the floor. 0.91m (3') above the floor there are two narrow shafts in the north and south walls (one is now filled by an extractor fan to try to circulate air in the pyramid). The purpose of these shafts is not clear: they appear to be aligned on stars or areas of the northern and southern skies, but on the other hand one of them follows a dog-leg course through the masonry so there was not intention to directly sight stars through them. They did not appear to contribute to air circulation, so the most likely explanation is a ritual one associated with the ascension of the king’s spirit.The King's Chamber is entirely faced with granite, the blocks of stone being fitted with such precision that it is impossible to insert a piece of paper between them. Above the roof, which is formed of nine slabs of stone weighing in total about 400 tons, are five compartments known as Relieving Chambers. The first four, like the King's Chamber, have flat roofs formed by the floor of the chamber above, but the final chamber has a pointed roof. Vyse suspected the presence of upper chambers when he found that he could push a long reed through a crack in the ceiling of the first chamber. From lower to upper, the chambers are known as "Davidson Chamber", "Wellington Chamber", "Lady Arbuthnot's Chamber" and "Campbell's Chamber". It is believed that the compartments were intended to safeguard the King's Chamber from the possibility of a roof collapsing under the weight of stone above the Chamber. As the chambers were not intended to be seen, they were not finished in any way and a few of the stones still retain mason's marks painted on them. One of the stones in Campbell's Chamber bears a mark, apparently the name of a work gang, which incorporates the only reference in the pyramid to Pharaoh Khufu.
The only object in the King's Chamber is a rectangular granite "sarcophagus", one corner of which is broken. The sarcophagus is slightly larger than the Ascending Passage, which indicates that it must have been placed in the Chamber before the roof was put in place. Unlike the fine masonry of the walls of the Chamber, the sarcophagus is roughly finished, with saw marks visible in several places. This is in contrast with the finely finished and decorated sarcophagi found in other pyramids of the same period. Petrie suggested that such a sarcophagus was intended but was lost in the river on the way north from Aswan and a hurriedly made replacement was used instead. This ingenious theory does not explain why the sarcophagus could not have been finished in situ.
Entrance

The entrance of the Pyramid
Today tourists enter the Great Pyramid via the Robbers' Tunnel dug by workmen employed by Caliph al-Ma'mun around AD 820. The tunnel is cut straight through the masonry of the pyramid for approximately 27m (90'), then turns sharply left to encounter the blocking stones in the Ascending Passage. Unable to remove these stones, the workmen tunnelled up beside them through the softer limestone of the Pyramid until they reached the Ascending Passage. It is possible to enter the Descending Passage from this point, but access is usually forbidden.
In recent years entrance to the pyramid has been restricted to groups of 100 morning and afternoon. As tickets are highly prized, those wishing to enter must queue outside the right ticket office for an hour or more before it opens. Under Zahi Hawass, photography inside the pyramid is now strictly forbidden.
King's Chamber and the Golden Mean
At the end of the lengthy series of entrance ways leading into the interior is the structure's main chamber, the King's Chamber. This granite room was originally 10 × 20 × 11.4 cubits, or about 5.235 m × 10.47 m × 5.974 m, comprising a double 10 × 10 cubit square floor, and a height equal to half the double square's diagonal. Some believed that the height was consistent with the geometric methods for determining the Golden Ratio φ (phi) as the height is approximately phi times the width minus ½, while phi can be derived from other dimensions of the pyramid, but evidence from Petrie’s surveys and later conclusions drawn by others shows that the circular proportions were deliberately incorporated into the internal and external designs of the Great Pyramid by its architects and builders for symbolic reasons. The so called golden ratio phi simply exists in the proportions of the architecture as an inadvertent by-product of the inclusion of the circular proportions. The reason for the inadvertent inclusion is that phi, the golden ratio, has a naturally occurring mathematical relation to the circular ratio pi that is unrelated to the architecture or geometry, and which was unknown to the pyramid's builders. Petrie confirmed that the King’s Chamber was a triumph of Egyptian geometry, the ratio of its length to the circuit of the side wall being the same as the ratio of 1 to pi, and that the exterior of the pyramid had been built to the same proportions.
Pyramid complex

Map of Giza pyramid complex
Main article: Giza pyramid complex
The Great Pyramid is surrounded by the usual complex of buildings. The Pyramid Temple, which stood on the east side of the pyramid and measured 52.2m (171') north to south and 40m (132') east to west, has almost entirely disappeared apart from the black basalt paving. There are only a few remnants of the causeway which linked the pyramid with the valley and the presumed Valley Temple which, if it exists, is buried beneath the village of Kafr es-Samman.
On the south side are the subsidiary pyramids, popularly known as Queens' Pyramids. Three remain standing to nearly full height but the fourth was so ruined that its existence was not suspected until the recent discovery of the first course of stones and the remains of the capstone. Herodotus claims that Khufu was a tyrant who prostituted his daughter to raise money to build the Great Pyramid. She, however, requested a stone from each customer and used them to build her smaller pyramid. There is no evidence to support this tale (though it may reflect an arranged marriage advantageous for Khufu) and the Queens' Pyramids may not have housed members of the court. Some have suggested that they corresponded to the later canopic jars for burial of the royal viscera - heart, lungs, liver and entrails.
Hidden beneath the paving around the pyramid was the tomb of Queen Hetepheres, sister-wife of Sneferu and mother of Khufu. Discovered by accident by the Reisner expedition, the burial was intact, though the carefully sealed coffin proved to be empty. Reisner suggests that Hetepheres was originally buried near her husband's pyramid but the tomb was robbed and the mummy destroyed. Khufu transferred the burial to his own pyramid complex, but the priests responsible for the burial did not dare tell him that his mother's body was missing.
There are three boat-shaped pits around the pyramid, of a size and shape to have held complete boats, though so shallow that any superstructure must have been removed or disassembled. It is not clear how these pits were sealed, as the span is too large for stone slabs, which may be why they were found empty apart from ropes and a few fragments of gilded wood found in one pit by Reisner. However in May, 1954, the Egyptian archaeologist Kamal el-Mallakh discovered a fourth pit, a long, narrow rectangle, still covered with slabs of stone weighing up to 15 tons. Inside were 1224 pieces of wood, the longest 23m (75') long, the shortest 10 cm (4"). These were entrusted to a native boat builder, Haj Ahmed Yusuf, who slowly and methodically worked out how the pieces fit together. The entire process, including conservation and straightening of the warped wood, took fourteen years.
The result is a spectacular cedar-wood boat 43.6m (143') long, its timbers held together by ropes. It is not clear how the boat was made water-tight. Early theories that soaking in water caused the wood to swell and thus become water-tight did not prove effective with the modern reconstruction "Horizon of Min" based on boats found in the Wadi Gawasis excavation and the reconstructers had recourse to traditional fibre caulking reinforced by beeswax. There is no sign of such measures on the Khufu boat, which may simply mean that the boat was never floated. The name "Djedefre", Khufu's son and successor, is found on some of the slabs of stone that sealed the pit, indicating that the boat was put there by Khufu's son.
The reconstructed boat is housed in a special boat-shaped, air-conditioned museum beside the pyramid. During construction of this museum, which stands above the boat pit, a second sealed boat pit was discovered. It was deliberately left unopened in the hope that future excavation techniques will allow more information to be recovered, however a hole was drilled in the sealing stones and air extracted from the pit in the hope of obtaining information about the ancient atmosphere. However as the air was found to be identical to modern air it was concluded that the pit is not hermetically sealed.
The Gizeh pyramid complex, which includes the pyramids of Khufu, Khafre and Menkaure, is surrounded by a cyclopaean stone wall, outside which Mark Lehner has discovered the town where the workers on the pyramids were housed. Among the discoveries are communal sleeping quarters, bakeries, breweries and kitchens (with evidence showing that bread and fish were staples of the diet), a hospital and a cemetery (where some of the skeletons were found with signs of trauma associated with accidents on a building site).
Thieves, tourists and excavators
Although succeeding pyramids were smaller, pyramid building continued until the end of the Middle Kingdom. However, as authors Briar and Hobbs claim, "all the pyramids were robbed" by the New Kingdom, when the construction of royal tombs in a desert valley, now known as the Valley of the Kings, began. Joyce Tyldesley states that the Great Pyramid itself "is known to have been opened and emptied by the Middle Kingdom", before the Arab caliph Abdullah al-Mamun entered the pyramid around AD 820.[

PHYSICS

2010-06-29T05:59:00.000-07:00

Physics
Physics (Greek: physis – φύσις meaning "nature") is a natural science that involves the study of matter and its motion through space-time, as well as all applicable concepts, such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the world and universe behave.
Physics is one of the oldest academic disciplines, perhaps the oldest through its inclusion of astronomy. Over the last two millennia, physics had been considered synonymous with philosophy, chemistry, and certain branches of mathematics and biology, but during the Scientific Revolution in the 16th century, it emerged to become a unique modern science in its own right. However, in some subject areas such as in mathematical physics and quantum chemistry, the boundaries of physics remain difficult to distinguish.
Physics is both significant and influential, in part because advances in its understanding have often translated into new technologies, but also because new ideas in physics often resonate with other sciences, mathematics, and philosophy. For example, advances in the understanding of electromagnetism or nuclear physics led directly to the development of new products which have dramatically transformed modern-day society (e.g., television, computers, domestic appliances, and nuclear weapons); advances in thermodynamics led to the development of motorized transport; and advances in mechanics inspired the development of calculus.
Scope and aims

This parabola-shaped lava flow illustrates Galileo's law of falling bodies as well as blackbody radiation – the temperature is discernible from the color of the blackbody.
Physics covers a wide range of phenomena, from the smallest sub-atomic particles (such as quarks, neutrinos and electrons), to the largest galaxies. Included in these phenomena are the most basic objects from which all other things are composed, and therefore physics is sometimes called the "fundamental science".
Physics aims to describe the various phenomena that occur in nature in terms of simpler phenomena. Thus, physics aims to both connect the things observable to humans to root causes, and then to try to connect these causes together in the hope of finding an ultimate reason for why nature is as it is. For example, the ancient Chinese observed that certain rocks (lodestone) were attracted to one another by some invisible force. This effect was later called magnetism, and was first rigorously studied in the 17th century.
A little earlier than the Chinese, the ancient Greeks knew of other objects such as amber, that when rubbed with fur would cause a similar invisible attraction between the two. This was also first studied rigorously in the 17th century, and came to be called electricity. Thus, physics had come to understand two observations of nature in terms of some root cause (electricity and magnetism). However, further work in the 19th century revealed that these two forces were just two different aspects of one force – electromagnetism. This process of "unifying" forces continues today .
The scientific method
Physicists use the scientific method to test the validity of a physical theory, using a methodical approach to compare the implications of the theory in question with the associated conclusions drawn from experiments and observations conducted to test it. Experiments and observations are to be collected and matched with the predictions and hypotheses made by a theory, thus aiding in the determination or the validity/invalidity of the theory.
Theories which are very well supported by data and have never failed any competent empirical test are often called scientific laws, or natural laws. Of course, all theories, including those called scientific laws, can always be replaced by more accurate, generalized statements if a disagreement of theory with observed data is ever found.
Theory and experiment

The astronaut and Earth are both in free-fall

Lightning is an electric current
The culture of physics has a higher degree of separation between theory and experiment than many other sciences. Since the twentieth century, most individual physicists have specialized in either theoretical physics or experimental physics. In contrast, almost all the successful theorists in biology and chemistry (e.g. American quantum chemist and biochemist Linus Pauling) have also been experimentalists, although this is changing as of late.
Theorists seek to develop mathematical models that both agree with existing experiments and successfully predict future results, while experimentalists devise and perform experiments to test theoretical predictions and explore new phenomena. Although theory and experiment are developed separately, they are strongly dependent upon each other. Progress in physics frequently comes about when experimentalists make a discovery that existing theories cannot explain, or when new theories generate experimentally testable predictions, which inspire new experiments.
It is also worth noting there are some physicists who work at the interplay of theory and experiment who are called phenomenologists. Phenomenologists look at the complex phenomena observed in experiment and work to relate them to fundamental theory.
Theoretical physics has historically taken inspiration from philosophy; electromagnetism was unified this way. Beyond the known universe, the field of theoretical physics also deals with hypothetical issues, such as parallel universes, a multiverse, and higher dimensions. Theorists invoke these ideas in hopes of solving particular problems with existing theories. They then explore the consequences of these ideas and work toward making testable predictions.
Experimental physics informs, and is informed by, engineering and technology. Experimental physicists involved in basic research design and perform experiments with equipment such as particle accelerators and lasers, whereas those involved in applied research often work in industry, developing technologies such as magnetic resonance imaging (MRI) and transistors. Feynman has noted that experimentalists may seek areas which are not well explored by theorists.
Relation to mathematics and the other sciences
In the Assayer (1622), Galileo noted that mathematics is the language in which Nature expresses its laws. Most experimental results in physics are numerical measurements, and theories in physics use mathematics to give numerical results to match these measurements.
Physics relies upon mathematics to provide the logical framework in which physical laws may be precisely formulated and predictions quantified. Whenever analytic solutions of equations are not feasible, numerical analysis and simulations may be utilized. Thus, scientific computation is an integral part of physics, and the field of computational physics is an active area of research.
A key difference between physics and mathematics is that since physics is ultimately concerned with descriptions of the material world, it tests its theories by comparing the predictions of its theories with data procured from observations and experimentation, whereas mathematics is concerned with abstract patterns, not limited by those observed in the real world. The distinction, however, is not always clear-cut. There is a large area of research intermediate between physics and mathematics, known as mathematical physics.
Physics is also intimately related to many other sciences, as well as applied fields like engineering and medicine. The principles of physics find applications throughout the other natural sciences as some phenomena studied in physics, such as the conservation of energy, are common to all material systems. Other phenomena, such as superconductivity, stem from these laws, but are not laws themselves because they only appear in some systems.
Physics is often said to be the "fundamental science" (chemistry is sometimes included), because each of the other disciplines (biology, chemistry, geology, material science, engineering, medicine etc.) deals with particular types of material systems that obey the laws of physics. For example, chemistry is the science of collections of matter (such as gases and liquids formed of atoms and molecules) and the processes known as chemical reactions that result in the change of chemical substances.
The structure, reactivity, and properties of a chemical compound are determined by the properties of the underlying molecules, which may be well-described by areas of physics such as quantum mechanics, or quantum chemistry, thermodynamics, and electromagnetism.
Philosophical implications
For more details on this topic, see Philosophy of Physics.
Physics in many ways stems from ancient Greek philosophy. From Thales' first attempt to characterize matter, to Democritus' deduction that matter ought to reduce to an invariant state, the Ptolemaic astronomy of a crystalline firmament, and Aristotle's book Physics, different Greek philosophers advanced their own theories of nature. Well into the 18th century, physics was known as "Natural philosophy".
By the 19th century physics was realized as a positive science and a distinct discipline separate from philosophy and the other sciences. Physics, as with the rest of science, relies on philosophy of science to give an adequate description of the scientific method. The scientific method employs a priori reasoning as well as a posteriori reasoning and the use of Bayesian inference to measure the validity of a given theory.
“ Truth is ever to be found in the simplicity, and not in the multiplicity and confusion of things. ”
—Isaac Newton

The development of physics has answered many questions of early philosophers, but has also raised new questions. Study of the philosophical issues surrounding physics, the philosophy of physics, involves issues such as the nature of space and time, determinism, and metaphysical outlooks such as empiricism, naturalism and realism.
Many physicists have written about the philosophical implications of their work, for instance Laplace, who championed causal determinism, and Erwin Schrödinger, who wrote on Quantum Mechanics. The mathematical physicist Roger Penrose has been called a Platonist by Stephen Hawking, a view Penrose discusses in his book, The Road to Reality. Hawking refers to himself as an "unashamed reductionist" and takes issue with Penrose's views.
History
Main article: History of physics
Isaac Newton (1643-1727)
Since antiquity, people have tried to understand the behavior of the natural world. One great mystery was the predictable behavior of celestial objects such as the Sun and the Moon. Several theories were proposed, the majority of which were disproved.
The philosopher Thales (ca. 624–546 BC) first refused to accept various supernatural, religious or mythological explanations for natural phenomena, proclaiming that every event had a natural cause. Early physical theories were largely couched in philosophical terms, and never verified by systematic experimental testing as is popular today. Many of the commonly accepted works of Ptolemy and Aristotle are not always found to match everyday observations.
Even so, many ancient philosophers and astronomers gave correct descriptions in atomism and astronomy. Leucippus (first half of 5th century BC) first proposed atomism, while Archimedes derived many correct quantitative descriptions of mechanics, statics and hydrostatics, including an explanation for the principle of the lever. The Middle Ages saw the emergence of an experimental physics taking shape among medieval Muslim physicists, the most famous being Alhazen, followed by modern physics largely taking shape among early modern European physicists, the most famous being Isaac Newton, who built on the works of Galileo Galilei and Johannes Kepler. In the 20th century, the work of Albert Einstein marked a new direction in physics that continues to the present day.
Core theories of physics
Further information: Branches of Physics, Classical physics, Modern physics, Topic outline of physics
While physics deals with a wide variety of systems, there are certain theories that are used by all physicists. Each of these theories were experimentally tested numerous times and found correct as an approximation of Nature (within a certain domain of validity). For instance, the theory of classical mechanics accurately describes the motion of objects, provided they are much larger than atoms and moving at much less than the speed of light. These theories continue to be areas of active research, and a remarkable aspect of classical mechanics known as chaos was discovered in the 20th century, three centuries after the original formulation of classical mechanics by Isaac Newton (1642–1727).
These central theories are important tools for research into more specialized topics, and any physicist, regardless of his or her specialization, is expected to be literate in them. These include classical mechanics, quantum mechanics, thermodynamics and statistical mechanics, electromagnetism, and special relativity.
Research fields
Contemporary research in physics can be broadly divided into condensed matter physics; atomic, molecular, and optical physics; particle physics; astrophysics; geophysics and biophysics. Some physics departments also support research in Physics education.
Since the twentieth century, the individual fields of physics have become increasingly specialized, and today most physicists work in a single field for their entire careers. "Universalists" such as Albert Einstein (1879–1955) and Lev Landau (1908–1968), who worked in multiple fields of physics, are now very rare.
Table of the major fields of physics, along with their subfields and the theories they employ
Field Subfields Major theories Concepts
Astrophysics
Astronomy, Astrometry, Cosmology, Gravitation physics, High-energy astrophysics, Planetary astrophysics, Plasma physics, Solar Physics, Space physics, Stellar astrophysics
Big Bang, Cosmic inflation, General relativity, Newton's law of universal gravitation, Lambda-CDM model, Magnetohydrodynamics
Black hole, Cosmic background radiation, Cosmic string, Cosmos, Dark energy, Dark matter, Galaxy, Gravity, Gravitational radiation, Gravitational singularity, Planet, Solar system, Star, Supernova, Universe

Atomic, molecular, and optical physics
Atomic physics, Molecular physics, Atomic and Molecular astrophysics, Chemical physics, Optics, Photonics
Quantum optics, Quantum chemistry, Quantum information science
Photon, Atom, Molecule, Diffraction, Electromagnetic radiation, Laser, Polarization (waves), Spectral line, Casimir effect

Particle physics
Nuclear physics, Nuclear astrophysics, Particle astrophysics, Particle physics phenomenology
Standard Model, Quantum field theory, Quantum electrodynamics, Quantum chromodynamics, Electroweak theory, Effective field theory, Lattice field theory, Lattice gauge theory, Gauge theory, Supersymmetry, Grand unification theory, Superstring theory, M-theory
Fundamental force (gravitational, electromagnetic, weak, strong), Elementary particle, Spin, Antimatter, Spontaneous symmetry breaking, Neutrino oscillation, Seesaw mechanism, Brane, String, Quantum gravity, Theory of everything, Vacuum energy

Condensed matter physics
Solid state physics, High pressure physics, Low-temperature physics, Surface Physics, Nanoscale and Mesoscopic physics, Polymer physics
BCS theory, Bloch wave, Density functional theory, Fermi gas, Fermi liquid, Many-body theory, Statistical Mechanics
Phases (gas, liquid, solid), Bose-Einstein condensate, Electrical conduction, Phonon, Magnetism, Self-organization, Semiconductor, superconductor, superfluid, Spin,

Applied Physics
Accelerator physics, Acoustics, Agrophysics, Biophysics, Chemical Physics, Communication Physics, Econophysics, Engineering physics, Fluid dynamics, Geophysics, Laser Physics, Materials physics, Medical physics, Nanotechnology, Optics, Optoelectronics, Photonics, Photovoltaics, Physical chemistry, Physics of computation, Plasma physics, Solid-state devices, Quantum chemistry, Quantum electronics, Quantum information science, Vehicle dynamics

Condensed matter

Main article: Condensed matter physics
Velocity-distribution data of a gas of rubidium atoms, confirming the discovery of a new phase of matter, the Bose–Einstein condensate
Condensed matter physics is the field of physics that deals with the macroscopic physical properties of matter. In particular, it is concerned with the "condensed" phases that appear whenever the number of constituents in a system is extremely large and the interactions between the constituents are strong.
The most familiar examples of condensed phases are solids and liquids, which arise from the bonding and electromagnetic force between atoms. More exotic condensed phases include the superfluid and the Bose–Einstein condensate found in certain atomic systems at very low temperature, the superconducting phase exhibited by conduction electrons in certain materials, and the ferromagnetic and antiferromagnetic phases of spins on atomic lattices.
Condensed matter physics is by far the largest field of contemporary physics. Historically, condensed matter physics grew out of solid-state physics, which is now considered one of its main subfields. The term condensed matter physics was apparently coined by Philip Anderson when he renamed his research group — previously solid-state theory — in 1967.
In 1978, the Division of Solid State Physics at the American Physical Society was renamed as the Division of Condensed Matter Physics. Condensed matter physics has a large overlap with chemistry, materials science, nanotechnology and engineering.
Atomic, molecular, and optical physics
Main article: Atomic, molecular, and optical physics
Atomic, molecular, and optical physics (AMO) is the study of matter-matter and light-matter interactions on the scale of single atoms or structures containing a few atoms. The three areas are grouped together because of their interrelationships, the similarity of methods used, and the commonality of the energy scales that are relevant. All three areas include both classical and quantum treatments; they can treat their subject from a microscopic view (in contrast to a macroscopic view).
Atomic physics studies the electron shells of atoms. Current research focuses on activities in quantum control, cooling and trapping of atoms and ions, low-temperature collision dynamics, the collective behavior of atoms in weakly interacting gases (Bose–Einstein Condensates and dilute Fermi degenerate systems), precision measurements of fundamental constants, and the effects of electron correlation on structure and dynamics. Atomic physics is influenced by the nucleus (see, e.g., hyperfine splitting), but intra-nuclear phenomenon such as fission and fusion are considered part of high energy physics.
Molecular physics focuses on multi-atomic structures and their internal and external interactions with matter and light. Optical physics is distinct from optics in that it tends to focus not on the control of classical light fields by macroscopic objects, but on the fundamental properties of optical fields and their interactions with matter in the microscopic realm.
High energy/particle physics
Main article: Particle physics
A simulated event in the CMS detector of the Large Hadron Collider, featuring a possible appearance of the Higgs boson.
Particle physics is the study of the elementary constituents of matter and energy, and the interactions between them. It may also be called "high energy physics", because many elementary particles do not occur naturally, but are created only during high energy collisions of other particles, as can be detected in particle accelerators.
Currently, the interactions of elementary particles are described by the Standard Model. The model accounts for the 12 known particles of matter that interact via the strong, weak, and electromagnetic fundamental forces. Dynamics are described in terms of matter particles exchanging messenger particles that carry the forces. These messenger particles are known as gluons; W− and W+ and Z bosons; and the photons, respectively. The Standard Model also predicts a particle known as the Higgs boson, the existence of which has not yet been verified.
Astrophysics
Main articles: Astrophysics and Physical cosmology
The deepest visible-light image of the universe, the Hubble Ultra Deep Field
Astrophysics and astronomy are the application of the theories and methods of physics to the study of stellar structure, stellar evolution, the origin of the solar system, and related problems of cosmology. Because astrophysics is a broad subject, astrophysicists typically apply many disciplines of physics, including mechanics, electromagnetism, statistical mechanics, thermodynamics, quantum mechanics, relativity, nuclear and particle physics, and atomic and molecular physics.
The discovery by Karl Jansky in 1931 that radio signals were emitted by celestial bodies initiated the science of radio astronomy. Most recently, the frontiers of astronomy have been expanded by space exploration. Perturbations and interference from the earth’s atmosphere make space-based observations necessary for infrared, ultraviolet, gamma-ray, and X-ray astronomy.
Physical cosmology is the study of the formation and evolution of the universe on its largest scales. Albert Einstein’s theory of relativity plays a central role in all modern cosmological theories. In the early 20th century, Hubble's discovery that the universe was expanding, as shown by the Hubble diagram, prompted rival explanations known as the steady state universe and the Big Bang.
The Big Bang was confirmed by the success of Big Bang nucleosynthesis and the discovery of the cosmic microwave background in 1964. The Big Bang model rests on two theoretical pillars: Albert Einstein's general relativity and the cosmological principle. Cosmologists have recently established a precise model of the evolution of the universe, which includes cosmic inflation, dark energy and dark matter.
Numerous possibilities and discoveries are anticipated to emerge from new Fermi data over the upcoming decade and vastly revise or clarify existing models of the Universe. In particular, the potential for a tremendous discovery surrounding dark matter is possible over the next several years. Fermi will search for evidence that dark matter is composed of weakly interacting massive particles, complementing similar experiments with the Large Hadron Collider and other underground detectors.
IBEX is already yielding new astrophysical discoveries: "No one knows what is creating the ENA (energetic neutral atoms) ribbon" along the termination shock of the solar wind, "but everyone agrees that it means the textbook picture of the heliosphere — in which the solar system's enveloping pocket filled with the solar wind's charged particles is plowing through the onrushing 'galactic wind' of the interstellar medium in the shape of a comet — is wrong."
Fundamental physics
The basic domains of physics
While physics aims to discover universal laws, its theories lie in explicit domains of applicability. Loosely speaking, the laws of classical physics accurately describe systems whose important length scales are greater than the atomic scale and whose motions are much slower than the speed of light. Outside of this domain, observations do not match their predictions. Albert Einstein contributed the framework of special relativity, which replaced notions of absolute time and space with spacetime and allowed an accurate description of systems whose components have speeds approaching the speed of light. Max Planck, Erwin Schrödinger, and others introduced quantum mechanics, a probabilistic notion of particles and interactions that allowed an accurate description of atomic and subatomic scales. Later, quantum field theory unified quantum mechanics and special relativity. General relativity allowed for a dynamical, curved spacetime, with which highly massive systems and the large-scale structure of the universe can be well described. General relativity has not yet been unified with the other fundamental descriptions.
Application and influence

Main article: Applied physics Archimedes' screw uses simple machines to lift liquids.
Applied physics is a general term for physics research which is intended for a particular use. An applied physics curriculum usually contains a few classes in an applied discipline, like geology or electrical engineering. It usually differs from engineering in that an applied physicist may not be designing something in particular, but rather is using physics or conducting physics research with the aim of developing new technologies or solving a problem.
The approach is similar to that of applied mathematics. Applied physicists can also be interested in the use of physics for scientific research. For instance, people working on accelerator physics might seek to build better particle detectors for research in theoretical physics.
Physics is used heavily in engineering. For example, Statics, a subfield of mechanics, is used in the building of bridges and other structures. The understanding and use of acoustics results in better concert halls; similarly, the use of optics creates better optical devices. An understanding of physics makes for more realistic flight simulators, video games, and movies, and is often critical in forensic investigations.
With the standard consensus that the laws of physics are universal and do not change with time, physics can be used to study things that would ordinarily be mired in uncertainty. For example, in the study of the origin of the Earth, one can reasonably model Earth's mass, temperature, and rate of rotation, over time. It also allows for simulations in engineering which drastically speed up the development of a new technology.
But there is also considerable interdisciplinarity in the physicist's methods, and so many other important fields are influenced by physics: e.g. presently the fields of econophysics plays an important role, as well as sociophysics.
Current research
Further information: List of unsolved problems in physics

Feynman diagram signed by R. P. Feynman
A typical event described by physics: a magnet levitating above a superconductor demonstrates the Meissner effect.
Research in physics is continually progressing on a large number of fronts.
In condensed matter physics, an important unsolved theoretical problem is that of high-temperature superconductivity. Many condensed matter experiments are aiming to fabricate workable spintronics and quantum computers.
In particle physics, the first pieces of experimental evidence for physics beyond the Standard Model have begun to appear. Foremost among these are indications that neutrinos have non-zero mass. These experimental results appear to have solved the long-standing solar neutrino problem, and the physics of massive neutrinos remains an area of active theoretical and experimental research. In the next several years, particle accelerators will begin probing energy scales in the TeV range, in which experimentalists are hoping to find evidence for the Higgs boson and supersymmetric particles.
Theoretical attempts to unify quantum mechanics and general relativity into a single theory of quantum gravity, a program ongoing for over half a century, have not yet been decisively resolved. The current leading candidates are M-theory, superstring theory and loop quantum gravity.
Many astronomical and cosmological phenomena have yet to be satisfactorily explained, including the existence of ultra-high energy cosmic rays, the baryon asymmetry, the acceleration of the universe and the anomalous rotation rates of galaxies.
Although much progress has been made in high-energy, quantum, and astronomical physics, many everyday phenomena involving complexity, chaos, or turbulence are still poorly understood. Complex problems that seem like they could be solved by a clever application of dynamics and mechanics remain unsolved; examples include the formation of sandpiles, nodes in trickling water, the shape of water droplets, mechanisms of surface tension catastrophes, and self-sorting in shaken heterogeneous collections.
These complex phenomena have received growing attention since the 1970s for several reasons, including the availability of modern mathematical methods and computers, which enabled complex systems to be modeled in new ways. Complex physics has become part of increasingly interdisciplinary research, as exemplified by the study of turbulence in aerodynamics and the observation of pattern formation in biological systems. In 1932, Horace Lamb said:
“ I am an old man now, and when I die and go to heaven there are two matters on which I hope for enlightenment. One is quantum electrodynamics, and the other is the turbulent motion of fluids. And about the former I am rather optimistic. ”
—Horace Lamb

MY DAD

2010-06-28T05:16:00.001-07:00

MY DAD (Father’s Day)

What I am today,
What I will be,
Because of him,
No sorrow I see.
My smile makes him happy,
A single tear, him sad.
I am the luckiest girl,
I have world’s bestest DAD.
He takes away my pains,
Comfort me always in stress.
He listens to my wishes insane,
And treat me like a warrior princes.
Always there for me, he is the one,
His shadow protects me from burning sun.
Like a gift from heavens is he!
Thank you! Dad what ever you did for me.
There is no measure made as such,
That tells that your princes love you how much.
Words to thank you I never will and never had,
Just I am sweetest daughter of world’s bestest DAD.
By Natasha Mubashar