Planet Earth

Pesticides A pesticide poisoning

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:23:00 +0000

A pesticide poisoning occurs when chemicals intended to control a pest affect non-target organisms such as humans, wildlife, or bees.

Pesticides , if used carefully and the manufacturers, instructions followed carefully they do not cause too much harm to the indoor air.

The most common exposure scenarios for pesticide-poisoning cases are accidental or suicidal poisonings, occupational exposure, by-stander exposure to off-target drift, and the general public who are exposed through environmental contamination

Tobacco smoking

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:15:00 +0000

A carbon footprint is "the total set of greenhouse gases (GHG) emissions caused by an organization, event or product" ^[1]. For simplicity of reporting, it is often expressed in terms of the amount of carbon dioxide, or its equivalent of other GHGs, emitted.

The concept name of the carbon footprint originates from ecological footprint discussion.^[2] The carbon footprint is a subset of the ecological footprint and of the more comprehensive Life Cycle Assessment (LCA).

An individual, nation, or organization's carbon footprint can be measured by undertaking a GHG emissions assessment. Once the size of a carbon footprint is known, a strategy can be devised to reduce it, e.g. by technological developments, better process and product management, changed Green Public or Private Procurement (GPP), Carbon capture, consumption strategies, and others.

The mitigation of carbon footprints through the development of alternative projects, such as solar or wind energy or reforestation, represents one way of reducing a carbon footprint and is often known as Carbon offsetting.

Tobacco smoke generates a wide range of harmful chemicals and is known to cause cancer. It is well known that passive smoking causes a wide range of problems to the passive smoker (the person who is in the same room with a smoker and is not himself/herself a smoker) ranging from burning eyes, nose, and throat irritation to cancer, bronchitis, severe asthma, and a decrease in lung function.

April 19, 2010 -- Secondhand smoke exposure contributes to as many as 40% of the roughly 30 million cases of chronic sinusitis among adults in the U.S., a new study shows.

Chronic sinusitis, also known as rhinosinusitis, is defined as allergic and non-allergic sinus inflammation lasting at least three months. Symptoms can include, but are not limited to, nasal congestion, facial pain, headache, and daytime or nighttime coughing.

In a 2006 report, the surgeon general estimated that 60% of nonsmokers in the U.S., or 126 million adults and children, are routinely exposed to secondhand smoke.
Secondhand smoke exposure has been implicated as a risk factor for a number of respiratory ailments, including asthma and other conditions including heart disease, sudden infant death syndrome, and cancers of the lung and sinus.

From tobacco smoke to kitchens, fireplaces, candles and incense burners, brush and wildfires, smoke within the home is increasingly common, and during cold or hot months when the windows are closed, indoor air quality and health can deteriorate. The air quality in the average home is five times worse than outside, and with smoke adding to the problem, it’s no surprise that serious health problems can result.

Tobacco Users Smoke Crack

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:12:00 +0000

Tobacco Users Smoke Crack

Recently uncovered internal tobacco industry memos and reports reveal that industry executives knew of the addictive nature of nicotine long before they disclosed this information to the public. In this profiled document , industry researchers discuss the similarities between nicotine, the addictive chemical in tobacco products, and drugs like cocaine, heroin and marijuana. Although the industry knew -- more than 30 years ago -- of the highly addictive nature of modern tobacco products, few people are aware that smoking cigarettes is similar to smoking crack cocaine.

The graphic at left illustrates the biosynthesis of alkaloids. Common alkaloids are cocaine, heroin and nicotine. As seen in the expanded illustration, nicotine and cocaine are very close "cousins" [2]. The media, and our society in general, place great emphasis on the negative social aspects of illicit substances like cocaine and heroin. Yet, as this evidence shows, nicotine and cocaine are essentially the same drug.

More importatntly, the table at left highlights the superior addictiveness of nicotine. Tragically, one quarter of the U.S. population functions daily only by taking hundreds of "hits" from a highly addictive chemical. This drug alters their mental functions, corrupts rationality, and literally, takes control over lives.

Indoor air pollution

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:09:00 +0000

Indoor air pollution

t refers to the physical, chemical, and biological characteristics of air in the indoor environment within a home, building, or an institution or commercial facility. Indoor air pollution is a concern in the developed countries, where energy efficiency improvements sometimes make houses relatively airtight, reducing ventilation and raising pollutant levels. Indoor air problems can be subtle and do not always produce easily recognized impacts on health. Different conditions are responsible for indoor air pollution in the rural areas and the urban areas.

In the developing countries, it is the rural areas that face the greatest threat from indoor pollution, where some 3.5 billion people continue to rely on traditional fuels such as firewood, charcoal, and cowdung for cooking and heating. Concentrations of indoor pollutants in households that burn traditional fuels are alarming. Burning such fuels produces large amount of smoke and other air pollutants in the confined space of the home, resulting in high exposure. Women and children are the groups most vulnerable as they spend more time indoors and are exposed to the smoke. In 1992, the World Bank designated indoor air pollution in the developing countries as one of the four most critical global environmental problems. Daily averages of pollutant level emitted indoors often exceed current WHO guidelines and acceptable levels. Although many hundreds of separate chemical agents have been identified in the smoke from biofuels, the four most serious pollutants are particulates, carbon monoxide, polycyclic organic matter, and formaldehyde. Unfortunately, little monitoring has been done in rural and poor urban indoor environments in a manner that is statistically rigorous.

In urban areas, exposure to indoor air pollution has increased due to a variety of reasons, including the construction of more tightly sealed buildings, reduced ventilation, the use of synthetic materials for building and furnishing and the use of chemical products, pesticides, and household care products. Indoor air pollution can begin within the building or be drawn in from outdoors. Other than nitrogen dioxide, carbon monoxide, and lead, there are a number of other pollutants that affect the air quality in an enclosed space.

Volatile organic compounds originate mainly from solvents and chemicals. The main indoor sources are perfumes, hair sprays, furniture polish, glues, air fresheners, moth repellents, wood preservatives, and many other products used in the house. The main health effect is the imitation of the eye, nose and throat. In more severe cases there may be headaches, nausea and loss of coordination. In the long term, some of the pollutants are suspected to damage to the liver and other parts of the body.

Pesticides , if used carefully and the manufacturers, instructions followed carefully they do not cause too much harm to the indoor air.

Biological pollutants include pollen from plants, mite, hair from pets, fungi, parasites, and some bacteria. Most of them are allergens and can cause asthma, hay fever, and other allergic diseases.

Formaldehyde is a gas that comes mainly from carpets, particle boards, and insulation foam. It causes irritation to the eyes and nose and may cause allergies in some people.

Asbestos is mainly a concern because it is suspected to cause cancer.

Radon is a gas that is emitted naturally by the soil. Due to modern houses having poor ventilation, it is confined inside the house causing harm to the dwellers.

Flyash

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:09:00 +0000

With the boom in population and industrial growth, the need for power has increased manifold. Nearly 73% of India’s total installed power generation capacity is thermal, of which 90% is coal-based generation, with diesel, wind, gas, and steam making up the rest. Thermal power generation through coal combustion produces minute particles of ash that causes serious environmental problems.

Commonly known as fly ash, these ash particles consist of silica, alumina, oxides of iron, calcium, and magnesium and toxic heavy metals like lead, arsenic, cobalt, and copper.

The 80-odd utility thermal power stations in India use bituminous coal and produce large quantities of fly ash. According to one estimate, up to 150 million tonnes of fly ash will be produced in India in the year 2000, primarily by thermal power plants and, to a lesser extent, by cement and steel plants and railways. This poses problems in the form of land use, health hazards, and environmental dangers. Both in disposal and in utilization utmost care has to be taken to safeguard the interest of human life, wild life, and such other considerations.

The prevalent practice is to dump fly ash on wastelands, and this has lain to waste thousands of hectares all over the country. To prevent the fly ash from getting airborne, the dumping sites have to be constantly kept wet by sprinkling water over the area. The coal industry in USA spends millions of dollars on lining fly ash dumping grounds. But in India, these sites are not lined and it leads to seepage, contaminating groundwater and soil. It lowers soil fertility and contaminates surface and ground water as it can leach into the subsoil. When fly ash gets into the natural draining system, it results in siltation and clogs the system. It also reduces the pH balance and portability of water. Fly ash interferes with the process of photosynthesis of aquatic plants and thus disturbs the food chain. Besides, fly ash corrodes exposed metallic structures in its vicinity.

In Delhi, the problem of fly ash is particularly severe as three power stations are located here. Being very minute, fly ash tends to remain airborne for a very long period leading to serious health problems as the airborne ash can enter the body. It causes irritation to eyes, skin, and nose, throat, and respiratory tract. Repeated inhalation of fly ash dust containing crystalline silica can cause bronchitis and lung cancer.

Tackling the problem of fly ash

Fly ash management has taken considerable strides over the past few years. Researches have been attempting to convert this waste into wealth by exploring viable avenues for fly ash management. Fly ash is oxide-rich and can be used as the raw material for different industries.

Today, fly ash bricks can be used as a building material. The American Embassy in India has used fly ash bricks in some of its recent construction. Use of fly ash as a part replacement of cement in mortar and concrete has started with the Indian Institute of Technology, Delhi taking the lead. Use of fly ash in the construction of roads and embankments has been successfully demonstrated in the country and it is gaining acceptance. The NTPC (National Thermal Power Corporation) is setting up two fly ash brick manufacturing plants at Badarpur and Dadri near Delhi.

At TERI, researchers have proven that fly ash dumps can be reclaimed by suitable addition of organic matter and symbiotic fungi, making it commercially viable for activities like floriculture and silviculture. TERI researchers have successfully reclaimed a part of an ash pond at the Badarpur Thermal Power Station by introducing a mycorrhizal fungi-based organic bio-fertilizer. As the fungus germinates, it sustains on the partner plant and quickly spreads to the roots and beyond. It improves the plant's water and nutrient uptake, helps in the development of roots and soil-binding, stores carbohydrates and oils for use when needed, protects the plants from soil-borne diseases, and detoxifies contaminated soils. This helps in keeping both air and water pollution under control. It also helps revive wastelands and saves millions of litres of precious water from going down the fly ash slurries. Marigold, tuberose, gladiolus, carnation, sunflower, poplar, sheesham, and eucalyptus now grow at the demonstration site of the power station.

Use of fly ash in agricultural applications has been well demonstrated and has been accepted by a large number of farmers.

The National Capital Power Station of the NTPC has come up with an innovative technology for commercial utilization of this by-product. Known as the dry ash technology, it is considered environment-friendly. Under the dry ash technology, the fly ash is collected in huge mounds with a filter bed provided at the bottom of the mound. Grass is planted on the slopes of the fly ash mounds and polymer layering is also done to prevent the ash from being blown by the wind. Fly ash treated by this method develops certain physical properties that make it more suitable for commercial purposes.

Acid rain

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:08:00 +0000

Another effect of air pollution is acid rain. The phenomenon occurs when sulphur dioxide and nitrogen oxides from the burning of fossil fuels such as, petrol, diesel, and coal combine with water vapour in the atmosphere and fall as rain, snow or fog. These gases can also be emitted from natural sources like volcanoes. Acid rain causes extensive damage to water, forest, soil resources and even human health. Many lakes and streams have been contaminated and this has led to the disappearance of some species of fish in Europe, USA and Canada as also extensive damage to forests and other forms of life. It is said that it can corrode buildings and be hazardous to human health. Because the contaminants are carried long distances, the sources of acid rain are difficult to pinpoint and hence difficult to control. For example, the acid rain that may have damaged some forest in Canada could have originated in the industrial areas of USA. In fact, this has created disagreements between Canada and the United States and among European countries over the causes of and solutions to the problem of acid rain. The international scope of the problem has led to the signing of international agreements on the limitation of sulphur and nitrogen oxide emissions.

Smog

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:06:00 +0000

The term smog was first used in 1905 by Dr H A Des Voeux to describe the conditions of fog that had soot or smoke in it. Smog is a combination of various gases with water vapour and dust. A large part of the gases that form smog is produced when fuels are burnt. Smog forms when heat and sunlight react with these gases and fine particles in the air. Smog can affect outlying suburbs and rural areas as well as big cities. Its occurrences are often linked to heavy traffic, high temperatures, and calm winds. During the winter, wind speeds are low and cause the smoke and fog to stagnate; hence pollution levels can increase near ground level. This keeps the pollution close to the ground, right where people are breathing. It hampers visibility and harms the environment. Heavy smog is greatly decreases ultraviolet radiation. In fact, in the early part of the 20th century, heavy smog in some parts of Europe resulted in a decrease in the production of natural vitamin D leading to a rise in the cases of rickets. Smog causes a misty haze similar to fog, but very different in composition. In fact the word smog has been coined from a combination of the words fog and smoke. Smog refers to hazy air that causes difficult breathing conditions.

The most harmful components of smog are ground-level ozone and fine airborne particles. Ground-level ozone forms when pollutants released from gasoline and diesel-powered vehicles and oil-based solvents react with heat and sunlight. It is harmful to humans, animals, and plants.

The industrial revolution in the 19th century saw the beginning of air pollution in Europe on a large scale and the presence of smog mainly in Britain. The industries and the households relied heavily on coal for heating and cooking. Due to the burning of coal for heat during the winter months, emissions of smoke and sulphur dioxide were much greater in urban areas than they were during the summer months. Smoke particles trapped in the fog gave it a yellow/black colour and this smog often settled over cities for many days.

The effects of smog on human health were evident, particularly when smog persisted for several days. Many people suffered respiratory problems and increased deaths were recorded, notably those relating to bronchial causes. A haze of dense harmful smog would often cover the city of London. The first smog-related deaths were recorded in London in 1873, when it killed 500 people. In 1880, the toll was 2000. London had one of its worst experiences with smog in December 1892. It lasted for three days and resulted in about 1000 deaths. London became quite notorious for its smog. By the end of the 19th century, many people visited London to see the fog. Despite gradual improvements in air quality during the 20th century, another major smog occurred in London in December 1952. The Great London Smog lasted for five days and resulted in about 4000 more deaths than usual. In response to the Great London Smog, the government passed its first Clean Air Act in 1956, which aimed to control domestic sources of smoke pollution by introducing smokeless zones. In addition, the introduction of cleaner coals led to a reduction in sulphur dioxide pollution. In the 1940s, severe smog began covering the city of Los Angeles in the USA.

Relatively little was done to control any type of pollution or to promote environmental protection until the middle of the 20th century. Today, smoke and sulphur dioxide pollution in cities is much lower than in the past, as a result of legislation to control pollution emissions and cleaner emission technology.

United States Environmental Protection Agency

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:05:00 +0000

The U.S. Environmental Protection Agency (EPA or sometimes USEPA) is an agency of the federal government of the United States charged to protect human health and the environment, by writing and enforcing regulations based on laws passed by Congress. The EPA was proposed by President Richard Nixon and began operation on December 2, 1970, when its establishment was passed by Congress, and signed into law by President Nixon, and has since been chiefly responsible for the environmental policy of the United States.^[2] It is led by its Administrator, who is appointed by the President of the United States. The EPA is not a Cabinet agency, but the Administrator is normally given cabinet rank. Lisa P. Jackson is the current Administrator. The agency has approximately 18,000 full-time employees.

Epidemiology

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:03:00 +0000

Epidemiology is the study of factors affecting the health and illness of populations, and serves as the foundation and logic of interventions made in the interest of public health and preventive medicine. It is considered a cornerstone methodology of public health research, and is highly regarded in evidence-based medicine for identifying risk factors for disease and determining optimal treatment approaches to clinical practice. In the study of communicable and non-communicable diseases, the work of epidemiologists ranges from outbreak investigation to study design, data collection and analysis including the development of statistical models to test hypotheses and the documentation of results for submission to peer-reviewed journals. Epidemiologists also study the interaction of diseases in a population, a condition known as a syndemic. Epidemiologists rely on a number of other scientific disciplines such as biology (to better understand disease processes), biostatistics (the current raw information available), Geographic Information Science (to store data and map disease patterns) and social science disciplines (to better understand proximate and distal risk factors).

Air pollution Indoor air quality (IAQ)

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:02:00 +0000

Indoor air quality (IAQ)

Indoor air quality (IAQ) is a term referring to the air quality within and around buildings and structures, especially as it relates to the health and comfort of building occupants.

IAQ can be affected by microbial contaminants (mold, bacteria), gases (including carbon monoxide, radon, volatile organic compounds), particulates, or any mass or energy stressor that can induce adverse health conditions. Indoor air is becoming an increasingly more concerning health hazard than outdoor air. Using ventilation to dilute contaminants, filtration, and source control are the primary methods for improving indoor air quality in most buildings.

Determination of IAQ involves the collection of air samples, monitoring human exposure to pollutants, collection of samples on building surfaces and computer modelling of air flow inside buildings.

A lack of ventilation indoors concentrates air pollution where people often spend the majority of their time. Radon (Rn) gas, a carcinogen, is exuded from the Earth in certain locations and trapped inside houses. Building materials including carpeting and plywood emit formaldehyde (H₂CO) gas. Paint and solvents give off volatile organic compounds (VOCs) as they dry. Lead paint can degenerate into dust and be inhaled. Intentional air pollution is introduced with the use of air fresheners, incense, and other scented items. Controlled wood fires in stoves and fireplaces can add significant amounts of smoke particulates into the air, inside and out^[10]. Indoor pollution fatalities may be caused by using pesticides and other chemical sprays indoors without proper ventilation.

Carbon monoxide (CO) poisoning and fatalities are often caused by faulty vents and chimneys, or by the burning of charcoal indoors. Chronic carbon monoxide poisoning can result even from poorly adjusted pilot lights. Traps are built into all domestic plumbing to keep sewer gas, hydrogen sulfide, out of interiors. Clothing emits tetrachloroethylene, or other dry cleaning fluids, for days after dry cleaning.

Though its use has now been banned in many countries, the extensive use of asbestos in industrial and domestic environments in the past has left a potentially very dangerous material in many localities. Asbestosis is a chronic inflammatory medical condition affecting the tissue of the lungs. It occurs after long-term, heavy exposure to asbestos from asbestos-containing materials in structures. Sufferers have severe dyspnea (shortness of breath) and are at an increased risk regarding several different types of lung cancer. As clear explanations are not always stressed in non-technical literature, care should be taken to distinguish between several forms of relevant diseases. According to the World Health Organisation (WHO), these may defined as; asbestosis, lung cancer, and mesothelioma (generally a very rare form of cancer, when more widespread it is almost always associated with prolonged exposure to asbestos).

Air pollution Emission factors

noreply@blogger.com (AH) — Wed, 21 Apr 2010 08:01:00 +0000

Air pollutant emission factors are representative values that attempt to relate the quantity of a pollutant released to the ambient air with an activity associated with the release of that pollutant. These factors are usually expressed as the weight of pollutant divided by a unit weight, volume, distance, or duration of the activity emitting the pollutant (e.g., kilograms of particulate emitted per megagram of coal burned). Such factors facilitate estimation of emissions from various sources of air pollution. In most cases, these factors are simply averages of all available data of acceptable quality, and are generally assumed to be representative of long-term averages.

The United States Environmental Protection Agency has published a compilation of air pollutant emission factors for a multitude of industrial sources. The United Kingdom, Australia, Canada and many other countries have published similar compilations, as well as the European Environment Agency

Air pollution

noreply@blogger.com (AH) — Wed, 21 Apr 2010 07:58:00 +0000

Air pollution is the introduction of chemicals, particulate matter, or biological materials that cause harm or discomfort to humans or other living organisms, or damages the natural environment into the atmosphere.
The air around us is getting more and more polluted. Find out why and what we can do about it.

The atmosphere is a complex dynamic natural gaseous system that is essential to support life on planet Earth. Stratospheric ozone depletion due to air pollution has long been recognized as a threat to human health as well as to the Earth's ecosystems.

Sabse Bada Kaun ?

noreply@blogger.com (AH) — Sun, 18 Apr 2010 09:46:00 +0000

Sabse Bada Kaun ?

management -pot-pourri

noreply@blogger.com (AH) — Sun, 18 Apr 2010 09:43:00 +0000

NATURE :-NATURE WALL PAPER | IMAGES | PHOTOS

noreply@blogger.com (AH) — Sat, 17 Apr 2010 07:38:00 +0000

NATURE
NATURE WALL PAPER | IMAGES | PHOTOS

EARTHQUAKE :- Earthquake TYPES

noreply@blogger.com (AH) — Sat, 17 Apr 2010 07:32:00 +0000

Earthquake TYPES

There are three main types of fault that may cause an earthquake: normal, reverse (thrust) and strike-slip. Normal and reverse faulting are examples of dip-slip, where the displacement along the fault is in the direction of dip and movement on them involves a vertical component. Normal faults occur mainly in areas where the crust is being extended such as a divergent boundary. Reverse faults occur in areas where the crust is being shortened such as at a convergent boundary. Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other ; transform boundaries are a particular type of strike-slip fault. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip; this is known as oblique slip.
Earthquakes away from plate boundaries

Where plate boundaries occur within continental lithosphere, deformation is spread out over a much larger area than the plate boundary itself. In the case of the San Andreas fault continental transform, many earthquakes occur away from the plate boundary and are related to strains developed within the broader zone of deformation caused by major irregularities in the fault trace (e.g. the “Big bend” region). The Northridge earthquake was associated with movement on a blind thrust within such a zone. Another example is the strongly oblique convergent plate boundary between the Arabian and Eurasian plates where it runs through the northwestern part of the Zagros mountains. The deformation associated with this plate boundary is partitioned into nearly pure thrust sense movements perpendicular to the boundary over a wide zone to the southwest and nearly pure strike-slip motion along the Main Recent Fault close to the actual plate boundary itself. This is demonstrated by earthquake focal mechanisms.

All tectonic plates have internal stress fields caused by their interactions with neighbouring plates and sedimentary loading or unloading (e.g. deglaciation). These stresses may be sufficient to cause failure along existing fault planes, giving rise to intraplate earthquakes.
Shallow-focus and deep-focus earthquakes

The majority of tectonic earthquakes originate at the ring of fire in depths not exceeding tens of kilometers. Earthquakes occurring at a depth of less than 70 km are classified as 'shallow-focus' earthquakes, while those with a focal-depth between 70 and 300 km are commonly termed 'mid-focus' or 'intermediate-depth' earthquakes. In subduction zones, where older and colder oceanic crust descends beneath another tectonic plate, deep-focus earthquakes may occur at much greater depths (ranging from 300 up to 700 kilometers).[4] These seismically active areas of subduction are known as Wadati-Benioff zones. Deep-focus earthquakes occur at a depth at which the subducted lithosphere should no longer be brittle, due to the high temperature and pressure. A possible mechanism for the generation of deep-focus earthquakes is faulting caused by olivine undergoing a phase transition into a spinel structure.[5]
Earthquakes and volcanic activity

Earthquakes often occur in volcanic regions and are caused there, both by tectonic faults and the movement of magma in volcanoes. Such earthquakes can serve as an early warning of volcanic eruptions, like during the Mount St. Helens eruption of 1980. Earthquake swarms can serve as markers for the location of the flowing magma throughout the volcanoes. These swarms can be recorded by seismometers and tiltimeters (a device which measures the ground slope) and used as sensors to predict imminent or upcoming eruptions.
Earthquake clusters

Most earthquakes form part of a sequence, related to each other in terms of location and time.[Most earthquake clusters consist of small tremors which cause little to no damage, but there is a theory that earthquakes can recur in a regular pattern.

EARTHQUAKE :- quake, tremor, temblor or seismic activity

noreply@blogger.com (AH) — Sat, 17 Apr 2010 07:30:00 +0000

An earthquake (also known as a quake, tremor, temblor or seismic activity) is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are recorded with a seismometer, also known as a seismograph. The moment magnitude (or the related and mostly obsolete Richter magnitude) of an earthquake is conventionally reported, with magnitude 3 or lower earthquakes being mostly imperceptible and magnitude 7 causing serious damage over large areas. Intensity of shaking is measured on the modified Mercalli scale.

At the Earth's surface, earthquakes manifest themselves by shaking and sometimes displacing the ground. When a large earthquake epicenter is located offshore, the seabed sometimes suffers sufficient displacement to cause a tsunami. The shaking in earthquakes can also trigger landslides and occasionally volcanic activity.

EARTHQUAKE

In its most generic sense, the word earthquake is used to describe any seismic event — whether a natural phenomenon or an event caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by volcanic activity, landslides, mine blasts, and nuclear experiments. An earthquake's point of initial rupture is called its focus or hypocenter. The term epicenter refers to the point at ground level directly above the hypocenter.

The 2010 Haiti earthquake was a catastrophic magnitude 7.0 Mw earthquake, with an epicentre near the town of Léogâne, approximately 25 km (16 miles) west of Port-au-Prince, Haiti's capital. The earthquake occurred at 16:53 local time (21:53 UTC) on Tuesday, 12 January 2010. By 24 January, at least 52 aftershocks measuring 4.5 or greater had been recorded. An estimated three million people were affected by the quake;the Haitian Government reported that an estimated 230,000 people had died, 300,000 had been injured and 1,000,000 made homeless.They also estimated that 250,000 residences and 30,000 commercial buildings had collapsed or were severely damaged.
The earthquake caused major damage to Port-au-Prince, Jacmel and other settlements in the region. Many notable landmark buildings were significantly damaged or destroyed, including the Presidential Palace, the National Assembly building, the Port-au-Prince Cathedral, and the main jail. Among those killed were Archbishop of Port-au-Prince Joseph Serge Miot,[12] and opposition leader Micha Gaillard.[13][14] The headquarters of the United Nations Stabilization Mission in Haiti (MINUSTAH), located in the capital, collapsed, killing many, including the Mission's Chief, Hédi Annabi.[15][16]

Many countries responded to appeals for humanitarian aid, pledging funds and dispatching rescue and medical teams, engineers and support personnel. Communication systems, air, land, and sea transport facilities, hospitals, and electrical networks had been damaged by the earthquake, which hampered rescue and aid efforts; confusion over who was in charge, air traffic congestion, and problems with prioritisation of flights further complicated early relief work. Port-au-Prince's morgues were quickly overwhelmed with many tens of thousands of bodies having to be buried in mass graves.[17] As rescues tailed off, supplies, medical care and sanitation became priorities. Delays in aid distribution led to angry appeals from aid workers and survivors, and some looting and sporadic violence being observed.

On 22 January the United Nations noted that the emergency phase of the relief operation was drawing to a close, and on the following day the Haitian government officially called off the search for survivors.

Ozone depletion :- Ozone cycle |

noreply@blogger.com (AH) — Sat, 17 Apr 2010 07:23:00 +0000

Ozone depletion describes two distinct, but related observations: a slow, steady decline of about 4 percent per decade in the total volume of ozone in Earth's stratosphere (the ozone layer) since the late 1970s, and a much larger, but seasonal, decrease in stratospheric ozone over Earth's polar regions during the same period. The latter phenomenon is commonly referred to as the ozone hole. In addition to this well-known stratospheric ozone depletion, there are also tropospheric ozone depletion events, which occur near the surface in polar regions during spring.

The detailed mechanism by which the polar ozone holes form is different from that for the mid-latitude thinning, but the most important process in both trends is catalytic destruction of ozone by atomic chlorine and bromine.[1] The main source of these halogen atoms in the stratosphere is photodissociation of chlorofluorocarbon (CFC) compounds, commonly called freons, and of bromofluorocarbon compounds known as halons. These compounds are transported into the stratosphere after being emitted at the surface.[2] Both ozone depletion mechanisms strengthened as emissions of CFCs and halons increased.

CFCs and other contributory substances are commonly referred to as ozone-depleting substances (ODS). Since the ozone layer prevents most harmful UVB wavelengths (270–315 nm) of ultraviolet light (UV light) from passing through the Earth's atmosphere, observed and projected decreases in ozone have generated worldwide concern leading to adoption of the Montreal Protocol that bans the production of CFCs and halons as well as related ozone depleting chemicals such as carbon tetrachloride and trichloroethane. It is suspected that a variety of biological consequences such as increases in skin cancer, cataracts,[3] damage to plants, and reduction of plankton populations in the ocean's photic zone may result from the increased UV exposure due to ozone depletion.

Ozone cycle overview

Three forms (or allotropes) of oxygen are involved in the ozone-oxygen cycle: oxygen atoms (O or atomic oxygen), oxygen gas (O₂ or diatomic oxygen), and ozone gas (O₃ or triatomic oxygen). Ozone is formed in the stratosphere when oxygen molecules photodissociate after absorbing an ultraviolet photon whose wavelength is shorter than 240 nm. This produces two oxygen atoms. The atomic oxygen then combines with O₂ to create O₃. Ozone molecules absorb UV light between 310 and 200 nm, following which ozone splits into a molecule of O₂ and an oxygen atom. The oxygen atom then joins up with an oxygen molecule to regenerate ozone. This is a continuing process which terminates when an oxygen atom "recombines" with an ozone molecule to make two O₂ molecules: O + O₃ → 2 O₂

_{he overall amount of ozone in the stratosphere is determined by a balance between photochemical production and recombination.

Ozone can be destroyed by a number of free radical catalysts, the most important of which are the hydroxyl radical (OH·), the nitric oxide radical (NO·), atomic chlorine (Cl·) and bromine (Br·). All of these have both natural and manmade sources; at the present time, most of the OH· and NO· in the stratosphere is of natural origin, but human activity has dramatically increased the levels of chlorine and bromine. These elements are found in certain stable organic compounds, especially chlorofluorocarbons (CFCs), which may find their way to the stratosphere without being destroyed in the troposphere due to their low reactivity. Once in the stratosphere, the Cl and Br atoms are liberated from the parent compounds by the action of ultraviolet light, e.g. ('h' is Planck's constant, 'ν' is frequency of electromagnetic radiation)

CFCl3 + hν → CFCl2 + Cl

The Cl and Br atoms can then destroy ozone molecules through a variety of catalytic cycles. In the simplest example of such a cycle,[4] a chlorine atom reacts with an ozone molecule, taking an oxygen atom with it (forming ClO) and leaving a normal oxygen molecule. The chlorine monoxide (i.e., the ClO) can react with a second molecule of ozone (i.e., O3) to yield another chlorine atom and two molecules of oxygen. The chemical shorthand for these gas-phase reactions is:

Cl + O3 → ClO + O2

ClO + O3 → Cl + 2 O2

The overall effect is a decrease in the amount of ozone. More complicated mechanisms have been discovered that lead to ozone destruction in the lower stratosphere as well.

A single chlorine atom would keep on destroying ozone (thus a catalyst) for up to two years (the time scale for transport back down to the troposphere) were it not for reactions that remove them from this cycle by forming reservoir species such as hydrogen chloride (HCl) and chlorine nitrate (ClONO2). On a per atom basis, bromine is even more efficient than chlorine at destroying ozone, but there is much less bromine in the atmosphere at present. As a result, both chlorine and bromine contribute significantly to the overall ozone depletion. Laboratory studies have shown that fluorine and iodine atoms participate in analogous catalytic cycles. However, in the Earth's stratosphere, fluorine atoms react rapidly with water and methane to form strongly-bound HF, while organic molecules which contain iodine react so rapidly in the lower atmosphere that they do not reach the stratosphere in significant quantities. Furthermore, a single chlorine atom is able to react with 100,000 ozone molecules. This fact plus the amount of chlorine released into the atmosphere by chlorofluorocarbons (CFCs) yearly demonstrates how dangerous CFCs are to the environment.}

Electricity and the Environment ISSUES | The Environmental Issues Of Electricity Production

noreply@blogger.com (AH) — Sat, 17 Apr 2010 07:17:00 +0000

Electricity and the Environment

The generation of electric power produces more pollution than any other single industry in the United States. Recent (2002) data shows the U.S. electricity industry was responsible for:[1]

63% of sulfur dioxide emissions that contribute to acid rain

22% of NOx emissions that contribute to urban smog

39% of carbon emissions that contribute to global climate change

33% of mercury emissions that pose significant health risks

Among the other major environmental issues linked to electricity are water impacts, generation of wastes, and the disruption of land uses.

Electricity is also playing an increasingly important role in our personal lives and in the economy that feeds us. Electricity powered computer and communication systems are more and more important parts our lives and our economy. Because we are demanding more electricity service we must avoid increasing the damage to our environment by using electricity efficiently and by obtaining electricity from the cleanest sources available.

How do we meet the energy needs of these people as they lift themselves from poverty while addressing pressing environmental impacts linked to their inevitable increase in power consumption? Find out how consumer choice offers ways to obtain cleaner electricity supplies

Also, click below for additional information on the various generating technologies (coal, natural gas, wind, etc.) that produce electric power and on the specific environmental issues (global warming, acid rain, toxic mercury emissions, water quality, and others) used by the Power Scorecard to rate electricity products.

The Environmental Issues Of Electricity Production

he variety of fuels used to generate electricity all have some impact on the environment. Fossil fuel power plants release air pollution, require large amounts of cooling water, and can mar large tracts of land during the mining process. Nuclear power plants are generating and accumulating copious quantities of radioactive waste that currently lack any repository. Even renewable energy facilities can affect wildlife (fish and birds), involve hazardous wastes, or require cooling water.

For specifics on any issue:

Air impacts
Climate change
Acid rain
Ozone (smog) and fine particulates
Air toxics (mercury)
Water impacts
Consumption of water resources
Pollution of water bodies
Land impacts
On-site land impacts
Off-site land impacts

Also see technologies for details on the various methods of producing electricity.

What causes global warming?

noreply@blogger.com (AH) — Sat, 17 Apr 2010 07:14:00 +0000

What causes global warming?

Many things cause global warming. One thing that causes global warming is electrical pollution. Electricity causes pollution in many ways, some worse than others. In most cases, fossil fuels are burned to create electricity. Fossil fuels are made of dead plants and animals. Some examples of fossil fuels are oil and petroleum. Many pollutants (chemicals that pollute the air, water, and land) are sent into the air when fossil fuels are burned. Some of these chemicals are called greenhouse gasses.

We use these sources of energy much more than the sources that give off less pollution. Petroleum, one of the sources of energy, is used a lot. It is used for transportation, making electricity, and making many other things. Although this source of energy gives off a lot of pollution, it is used for 38% of the United States’ energy.

Some other examples of using energy and polluting the air are:

	Turning on a light
	Watching T.V.
	Listening to a stereo
	Washing or drying clothes
	Using a hair dryer
	Riding in a car
	Heating a meal in the microwave
	Using an air conditioner
	Playing a video game
	Using a dish washer

When you do these things, you are causing more greenhouse gasses to be sent into the air. Greenhouse gasses are sent into the air because creating the electricity you use to do these things causes pollution. If you think of how many times a day you do these things, it’s a lot. You even have to add in how many other people do these things! That turns out to be a lot of pollutants going into the air a day because of people like us using electricity. The least amount of electricity you use, the better.

When we throw our garbage away, the garbage goes to landfills. Landfills are those big hills that you go by on an expressway that stink. They are full of garbage. The garbage is then sometimes burned. This sends an enormous amount of greenhouse gasses into the air and makes global warming worse.

Another thing that makes global warming worse is when people cut down trees. Trees and other plants collect carbon dioxide (CO2), which is a greenhouse gas.

Carbon dioxide is the air that our body lets out when we breathe. With fewer trees, it is harder for people to breathe because there is more CO2 in the air, and we don’t breathe CO2, we breathe oxygen. Plants collect the CO2 that we breathe out, and they give back oxygen that we breathe in. With less trees and other plants, such as algae, there is less air for us, and more greenhouse gases are sent into the air. This means that it is very important to protect our trees to stop the greenhouse effect, and also so we can breathe and live.

This gas, CO2, collects light and heat (radiant energy), produced by the sun, and this makes the earth warmer. The heat and light from the sun is produced in the center of the sun. (The sun has layers just like the earth.)

This layer is called the core. Just like a core of an apple, it is in the middle. Here there is a very high temperature, about 27,000,000°F. This heat escapes out of this layer to the next layer, the radiative zone. This layer is cooler, about 4,500,000°F. Gradually, the heat and light will pass through the convection zone at a temperature of around 2,000,000°F. When it gets to the surface, the temperature is about 10,000°F. Finally, the heat and light is sent into space. This is called radiant energy (heat and light). The radiant energy reaches the earth’s atmosphere. As a result of this process we get light and heat. When you pollute, you send chemicals into the air that destroy our atmosphere, so more heat and light cannot escape from the earth’s atmosphere.

The dirty yellow color on outside is the surface. The light and dark yellow colored area is the convection zone. The orange colored area is the radiative zone, and the red colored area is the core. The squiggle lines represent radiant energy.

What is the greenhouse effect? What are greenhouse gasses?

noreply@blogger.com (AH) — Sat, 17 Apr 2010 07:12:00 +0000

The greenhouse effect is when the temperature rises because the sun’s heat and light is trapped in the earth’s atmosphere. This is like when heat is trapped in a car. On a very hot day, the car gets hotter when it is out in the parking lot. This is because the heat and light from the sun can get into the car, by going through the windows, but it can’t get back out. This is what the greenhouse effect does to the earth. The heat and light can get through the atmosphere, but it can’t get out. As a result, the temperature rises.

The sun’s heat can get into the car through the windows but is then trapped. This makes what ever the place might be, a greenhouse, a car, a building, or the earth’s atmosphere, hotter. This diagram shows the heat coming into a car as visible light (light you can see) and infrared light (heat). Once the light is inside the car, it is trapped and the heat builds up, just like it does in the earth’s atmosphere.

Sometimes the temperature can change in a way that helps us. The greenhouse effect makes the earth appropriate for people to live on. Without it, the earth would be freezing, or on the other hand it would be burning hot. It would be freezing at night because the sun would be down. We would not get the sun’s heat and light to make the night somewhat warm. During the day, especially during the summer, it would be burning because the sun would be up with no atmosphere to filter it, so people, plants, and animals would be exposed to all the light and heat.

Although the greenhouse effect makes the earth able to have people living on it, if there gets to be too many gases, the earth can get unusually warmer, and many plants, animals, and people will die. They would die because there would be less food (plants like corn, wheat, and other vegetables and fruits). This would happen because the plants would not be able to take the heat. This would cause us to have less food to eat, but it would also limit the food that animals have. With less food, like grass, for the animals that we need to survive (like cows) we would even have less food. Gradually, people, plants, and animals would all die of hunger.

What are greenhouse gasses?

Greenhouse gasses are gasses are in the earth’s atmosphere that collect heat and light from the sun. With too many greenhouse gasses in the air, the earth’s atmosphere will trap too much heat and the earth will get too hot. As a result people, animals, and plants would die because the heat would be too strong.

GLOBAL WARMING :- Definitions of global warming

noreply@blogger.com (AH) — Sat, 17 Apr 2010 07:09:00 +0000

Global warming is when the earth heats up (the temperature rises). It happens when greenhouse gases (carbon dioxide, water vapor, nitrous oxide, and methane) trap heat and light from the sun in the earth’s atmosphere, which increases the temperature. This hurts many people, animals, and plants. Many cannot take the change, so they die.

an increase in the average temperature of the earth's atmosphere (especially a sustained increase that causes climatic changes)
Global Warming is an album by jazz saxophonist Sonny Rollins, released on the Milestone label in 1998, featuring performances by Rollins with ...

An overall increase in world temperatures which may be caused by additional heat being trapped by greenhouse gases.
The progressive gradual rise of the earth's surface temperature thought to be caused by the greenhouse effect and responsible for changes in global climate patterns. An increase in the near surface temperature of the Earth. ...

An increase in the Earth's temperature caused by human activities, such as burning coal, oil and natural gas. This releases carbon dioxide, methane, and other greenhouse gases into the atmosphere. ...

The greenhouse effect acts to warm the plant and increase average global temperatures. This is seen as a major environmental hazard as average temperatures rise, leading to a possible change in weather patterns and agricultural output. ...
The term given to the major consequence of the greenhouse effect. Scientists have long predicted and recently measured notable increases in the world's temperature. ...

A process that raises the air temperature in the lower atmosphere due to heat trapped by greenhouse gases, such as carbon dioxide, methane, nitrous oxide, CFCs and ozone. ...

terms "climate change" and "global warming" are often used to mean the same thing. Global warming emphasises the rise in average temperatures of the earth.

The warming of the lower atmosphere due to the increased emission of greenhouse gases.

The theory that the world's average temperature is increasing due to the burning of fossil fuels and other forms of energy resulting in higher atmospheric concentrations of gases such as carbon dioxide.

A gradual warming of the Earth's atmosphere reportedly caused by the burning of fossil fuels and industrial pollutants.

The idea that increased greenhouse gases cause the Earth's temperature to rise globally. (See climate change).

The steady rise in global average temperature in recent decades, which experts believe is largely caused by man-made greenhouse gas emissions. The long-term trend continues upwards, they suggest, even though the warmest year on record, according to the UK's Met Office, is 1998.

Global warming relates to the increase in the average temperature of the Earth's surface that has been observed in recent years, and it is projected to continue. It is debated as to whether this is a natural occurrence or whether human activity has impacted or accelerated it. ...

GLOBAL WARMING :- MEANING | DEFFINATION | IMAGES | ISSUES AND MORE

noreply@blogger.com (AH) — Sat, 17 Apr 2010 07:05:00 +0000

Global warming is the increase in the average temperature of Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) between the start and the end of the 20th century. The Intergovernmental Panel on Climate Change (IPCC) concludes that most of the observed temperature increase since the middle of the 20th century was very likely caused by increasing concentrations of greenhouse gases resulting from human activity such as fossil fuel burning and deforestation. The IPCC also concludes that variations in natural phenomena such as solar radiation and volcanic eruptions had a small cooling effect after 1950. These basic conclusions have been endorsed by more than 40 scientific societies and academies of science, including all of the national academies of science of the major industrialized countries.[

Climate model projections summarized in the latest IPCC report indicate that the global surface temperature is likely to rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the 21st century.The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions. Most studies focus on the period leading up to the year 2100. However, warming is expected to continue beyond 2100 even if emissions stop, because of the large heat capacity of the oceans and the long lifetime of carbon dioxide in the atmosphere.

An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers, permafrost and sea ice. Other likely effects include changes in the frequency and intensity of extreme weather events, species extinctions, and changes in agricultural yields. Warming and related changes will vary from region to region around the globe, though the nature of these regional variations is uncertain.
Political and public debate continues regarding global warming, its causes and what actions to take in response. The available options are mitigation to reduce further emissions; adaptation to reduce the damage caused by warming; and, more speculatively, geoengineering to reverse global warming. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions.

Temperature changes

The most common measure of global warming is the trend in globally averaged temperature near the Earth's surface. Expressed as a linear trend, this temperature rose by 0.74 ± 0.18 °C over the period 1906–2005. The rate of warming over the last half of that period was almost double that for the period as a whole (0.13 ± 0.03 °C per decade, versus 0.07 °C ± 0.02 °C per decade). The urban heat island effect is estimated to account for about 0.002 °C of warming per decade since 1900.[10] Temperatures in the lower troposphere have increased between 0.13 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to satellite temperature measurements. Temperature is believed to have been relatively stable over the one or two thousand years before 1850, with regionally varying fluctuations such as the Medieval Warm Period and the Little Ice Age.[11]

Estimates by NASA's Goddard Institute for Space Studies and the National Climatic Data Center show that 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree.[12][13] Estimates prepared by the World Meteorological Organization and the Climatic Research Unit show 2005 as the second warmest year, behind 1998.[14][15] Temperatures in 1998 were unusually warm because the strongest El Niño in the past century occurred during that year.[16] Global temperature is subject to short-term fluctuations that overlay long term trends and can temporarily mask them. The relative stability in temperature from 2002 to 2009 is consistent with such an episode

Definitions of global warming

What is global warming?

What is the greenhouse effect?

Evaluation | Introduction to Evaluation | Definitions | Evaluation Strategies

noreply@blogger.com (AH) — Fri, 16 Apr 2010 15:12:00 +0000

Introduction to Evaluation

Evaluation is a methodological area that is closely related to, but distinguishable from more traditional social research. Evaluation utilizes many of the same methodologies used in traditional social research, but because evaluation takes place within a political and organizational context, it requires group skills, management ability, political dexterity, sensitivity to multiple stakeholders and other skills that social research in general does not rely on as much. Here we introduce the idea of evaluation and some of the major terms and issues in the field.

Definitions of Evaluation

Probably the most frequently given definition is:

Evaluation is the systematic assessment of the worth or merit of some object

This definition is hardly perfect. There are many types of evaluations that do not necessarily result in an assessment of worth or merit -- descriptive studies, implementation analyses, and formative evaluations, to name a few. Better perhaps is a definition that emphasizes the information-processing and feedback functions of evaluation. For instance, one might say:

Evaluation is the systematic acquisition and assessment of information to provide useful feedback about some object

Both definitions agree that evaluation is a systematic endeavor and both use the deliberately ambiguous term 'object' which could refer to a program, policy, technology, person, need, activity, and so on. The latter definition emphasizes acquiring and assessing information rather than assessing worth or merit because all evaluation work involves collecting and sifting through data, making judgements about the validity of the information and of inferences we derive from it, whether or not an assessment of worth or merit results.

The Goals of Evaluation

The generic goal of most evaluations is to provide "useful feedback" to a variety of audiences including sponsors, donors, client-groups, administrators, staff, and other relevant constituencies. Most often, feedback is perceived as "useful" if it aids in decision-making. But the relationship between an evaluation and its impact is not a simple one -- studies that seem critical sometimes fail to influence short-term decisions, and studies that initially seem to have no influence can have a delayed impact when more congenial conditions arise. Despite this, there is broad consensus that the major goal of evaluation should be to influence decision-making or policy formulation through the provision of empirically-driven feedback.

Evaluation Strategies

'Evaluation strategies' means broad, overarching perspectives on evaluation. They encompass the most general groups or "camps" of evaluators; although, at its best, evaluation work borrows eclectically from the perspectives of all these camps. Four major groups of evaluation strategies are discussed here.

Scientific-experimental models are probably the most historically dominant evaluation strategies. Taking their values and methods from the sciences -- especially the social sciences -- they prioritize on the desirability of impartiality, accuracy, objectivity and the validity of the information generated. Included under scientific-experimental models would be: the tradition of experimental and quasi-experimental designs; objectives-based research that comes from education; econometrically-oriented perspectives including cost-effectiveness and cost-benefit analysis; and the recent articulation of theory-driven evaluation.

The second class of strategies are management-oriented systems models. Two of the most common of these are PERT, the Program Evaluation and Review Technique, and CPM, the Critical Path Method. Both have been widely used in business and government in this country. It would also be legitimate to include the Logical Framework or "Logframe" model developed at U.S. Agency for International Development and general systems theory and operations research approaches in this category. Two management-oriented systems models were originated by evaluators: the UTOS model where U stands for Units, T for Treatments, O for Observing Observations and S for Settings; and the CIPP model where the C stands for Context, the IP for Process and the second P for Product. These management-oriented systems models emphasize comprehensiveness in evaluation, placing evaluation within a larger framework of organizational activities. for Input, the first

The third class of strategies are the qualitative/anthropological models. They emphasize the importance of observation, the need to retain the phenomenological quality of the evaluation context, and the value of subjective human interpretation in the evaluation process. Included in this category are the approaches known in evaluation as naturalistic or 'Fourth Generation' evaluation; the various qualitative schools; critical theory and art criticism approaches; and, the 'grounded theory' approach of Glaser and Strauss among others.

Finally, a fourth class of strategies is termed participant-oriented models. As the term suggests, they emphasize the central importance of the evaluation participants, especially clients and users of the program or technology. Client-centered and stakeholder approaches are examples of participant-oriented models, as are consumer-oriented evaluation systems.

With all of these strategies to choose from, how to decide? Debates that rage within the evaluation profession -- and they do rage -- are generally battles between these different strategists, with each claiming the superiority of their position. In reality, most good evaluators are familiar with all four categories and borrow from each as the need arises. There is no inherent incompatibility between these broad strategies -- each of them brings something valuable to the evaluation table. In fact, in recent years attention has increasingly turned to how one might integrate results from evaluations that use different strategies, carried out from different perspectives, and using different methods. Clearly, there are no simple answers here. The problems are complex and the methodologies needed will and should be varied.

Types of Evaluation

There are many different types of evaluations depending on the object being evaluated and the purpose of the evaluation. Perhaps the most important basic distinction in evaluation types is that between formative and summative evaluation. Formative evaluations strengthen or improve the object being evaluated -- they help form it by examining the delivery of the program or technology, the quality of its implementation, and the assessment of the organizational context, personnel, procedures, inputs, and so on. Summative evaluations, in contrast, examine the effects or outcomes of some object -- they summarize it by describing what happens subsequent to delivery of the program or technology; assessing whether the object can be said to have caused the outcome; determining the overall impact of the causal factor beyond only the immediate target outcomes; and, estimating the relative costs associated with the object.

Formative evaluation includes several evaluation types:

needs assessment determines who needs the program, how great the need is, and what might work to meet the need
evaluability assessment determines whether an evaluation is feasible and how stakeholders can help shape its usefulness
structured conceptualization helps stakeholders define the program or technology, the target population, and the possible outcomes
implementation evaluation monitors the fidelity of the program or technology delivery
process evaluation investigates the process of delivering the program or technology, including alternative delivery procedures

Summative evaluation can also be subdivided:

outcome evaluations investigate whether the program or technology caused demonstrable effects on specifically defined target outcomes
impact evaluation is broader and assesses the overall or net effects -- intended or unintended -- of the program or technology as a whole
cost-effectiveness and cost-benefit analysis address questions of efficiency by standardizing outcomes in terms of their dollar costs and values
secondary analysis reexamines existing data to address new questions or use methods not previously employed
meta-analysis integrates the outcome estimates from multiple studies to arrive at an overall or summary judgement on an evaluation question

Evaluation Questions and Methods

Evaluators ask many different kinds of questions and use a variety of methods to address them. These are considered within the framework of formative and summative evaluation as presented above.

In formative research the major questions and methodologies are:

What is the definition and scope of the problem or issue, or what's the question?

Formulating and conceptualizing methods might be used including brainstorming, focus groups, nominal group techniques, Delphi methods, brainwriting, stakeholder analysis, synectics, lateral thinking, input-output analysis, and concept mapping.

Where is the problem and how big or serious is it?

The most common method used here is "needs assessment" which can include: analysis of existing data sources, and the use of sample surveys, interviews of constituent populations, qualitative research, expert testimony, and focus groups.

How should the program or technology be delivered to address the problem?

Some of the methods already listed apply here, as do detailing methodologies like simulation techniques, or multivariate methods like multiattribute utility theory or exploratory causal modeling; decision-making methods; and project planning and implementation methods like flow charting, PERT/CPM, and project scheduling.

How well is the program or technology delivered?

Qualitative and quantitative monitoring techniques, the use of management information systems, and implementation assessment would be appropriate methodologies here.

The questions and methods addressed under summative evaluation include:

What type of evaluation is feasible?

Evaluability assessment can be used here, as well as standard approaches for selecting an appropriate evaluation design.

What was the effectiveness of the program or technology?

One would choose from observational and correlational methods for demonstrating whether desired effects occurred, and quasi-experimental and experimental designs for determining whether observed effects can reasonably be attributed to the intervention and not to other sources.

What is the net impact of the program?

Econometric methods for assessing cost effectiveness and cost/benefits would apply here, along with qualitative methods that enable us to summarize the full range of intended and unintended impacts.

Clearly, this introduction is not meant to be exhaustive. Each of these methods, and the many not mentioned, are supported by an extensive methodological research literature. This is a formidable set of tools. But the need to improve, update and adapt these methods to changing circumstances means that methodological research and development needs to have a major place in evaluation work.

Planet Earth

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top five problems smoke can cause

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Tobacco Users Smoke Crack

Indoor air pollution

Flyash

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Smog

United States Environmental Protection Agency

Epidemiology

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Indoor air quality (IAQ)

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Sabse Bada Kaun ?

management -pot-pourri

NATURE :-NATURE WALL PAPER | IMAGES | PHOTOS

EARTHQUAKE :- Earthquake TYPES

EARTHQUAKE :- quake, tremor, temblor or seismic activity

Ozone depletion :- Ozone cycle |

Ozone cycle overview

Electricity and the Environment ISSUES | The Environmental Issues Of Electricity Production

What causes global warming?

What is the greenhouse effect? What are greenhouse gasses?

GLOBAL WARMING :- Definitions of global warming

GLOBAL WARMING :- MEANING | DEFFINATION | IMAGES | ISSUES AND MORE

Temperature changes

Definitions of global warming

Evaluation | Introduction to Evaluation | Definitions | Evaluation Strategies

Introduction to Evaluation

Definitions of Evaluation

The Goals of Evaluation

Evaluation Strategies

Types of Evaluation

Evaluation Questions and Methods

In formative research the major questions and methodologies are:

The questions and methods addressed under summative evaluation include: