ScienceAll

Leaving bed unmade could kill Dust mite

2017-11-22T10:39:00.000+06:00

Dust Mite

Dust mites are everywhere, and feed on scales of human skin; they also produce allergens that can be inhaled during sleep. And approximately 1.5 million of them are hanging out with you every night when you go to sleep. When you return from running and screaming around your room, here's the solution to get rid of them: Don't make the bed! The bugs are happiest in a warm, moist environment and are more likely to die off when that environment changes. Keeping the sheets wide open helps in their demise.

However, a segment on NBC’s Today show recently revealed a decade-old theory from BBC News that suggests there is one thing you can do to keep the mites at bay — stop making your bed.

A Kingston University study discovered the bugs cannot survive in the warm, dry conditions found in an unmade bed. The average bed could be home to up to 1.5 million house dust mites. The bugs, which are less than a millimeter long, feed on scales of human skin and produce allergens which are easily inhaled during sleep. The warm, damp conditions created in an occupied bed are ideal for the creatures, but they are less likely to thrive when moisture is in shorter supply. 'Small glands' The scientists developed a computer model to track how changes in the home can reduce numbers of dust mites in beds. Researcher Dr Stephen Pretlove said: "We know that mites can only survive by taking in water from the atmosphere using small glands on the outside of their body. "Something as simple as leaving a bed unmade during the day can remove moisture from the sheets and mattress so the mites will dehydrate and eventually die."

Skill at game and intelligence linked with multiplayer video games

2017-11-19T21:38:00.000+06:00

Credit: © sezer66 / Fotolia

Researchers at the University of York have discovered a link between young people's ability to perform well at two popular video games and high levels of intelligence.

Studies carried out at the Digital Creativity Labs (DC Labs) at York found that some action strategy video games can act like IQ tests. The researchers' findings are published today in the journal PLOS ONE.

The York researchers stress the studies have no bearing on questions such as whether playing computer games makes young people smarter or otherwise. They simply establish a correlation between skill at certain online games of strategy and intelligence.

The researchers focused on 'Multiplayer Online Battle Arenas' (MOBAs) -- action strategy games that typically involve two opposing teams of five individuals -- as well as multiplayer 'First Person Shooter' games. These types of games are hugely popular with hundreds of millions of players worldwide.

The team from York's Departments of Psychology and Computer Science carried out two studies. The first examined a group of subjects who were highly experienced in the MOBA League of Legends -- one of the most popular strategic video games in the world with millions of players each day.

In this study, the researchers observed a correlation between performance in the strategic game League of Legends and performance in standard paper-and-pencil intelligence tests.

The second study analysed big datasets from four games: Two MOBAs (League of Legends and Defence of the Ancients 2 (DOTA 2)) and two 'First Person Shooters' (Destiny and Battlefield 3). First Person Shooters (FPSs) are games involving shooting enemies and other targets, with the player viewing the action as though through the eyes of the character they are controlling.

In this second study, they found that for large groups consisting of thousands of players, performance in MOBAs and IQ behave in similar ways as players get older. But this effect was not found for First Person Shooters, where performance declined after the teens.

The researchers say the correlation between ability at action strategy video games such as League of Legends and Defence of the Ancients 2 (DOTA 2) and a high IQ is similar to the correlation seen in other more traditional strategy games such as chess.

Corresponding author Professor Alex Wade of the University of York's Department of Psychology and Digital Creativity Labs said: "Games such as League of Legends and DOTA 2 are complex, socially-interactive and intellectually demanding. Our research would suggest that your performance in these games can be a measure of intelligence.

"Research in the past has pointed to the fact that people who are good at strategy games such as chess tend to score highly at IQ tests. Our research has extended this to games that millions of people across the planet play every day."

The discovery of this correlation between skill and intelligence opens up a huge new data source. For example, as 'proxy' tests of IQ, games could be useful at a global population level in fields such as 'cognitive epidemiology' -- research that examines the associations between intelligence and health across time -- and as a way of monitoring cognitive health across populations.

Athanasios Kokkinakis, a PhD student with the EPSRC Centre for Intelligent Games and Game Intelligence (IGGI) research programme at York, is the lead author on the study.

He said: "Unlike First Person Shooter (FPS) games where speed and target accuracy are a priority, Multiplayer Online Battle Arenas rely more on memory and the ability to make strategic decisions taking into account multiple factors.

"It is perhaps for these reasons that we found a strong correlation between skill and intelligence in MOBAs."

Co-author Professor Peter Cowling, Director of DC Labs and the IGGI programme at York, said: "This cutting-edge research has the potential for substantial impact on the future of the games and creative industries -- and on games as a tool for research in health and psychology.

"The IGGI programme has 48 excellent PhD students working with industry and across disciplines -- there is plenty more to come!"

Source: ScienceDaily

Neanderthals survived at least 3,000 years longer in Spain than we thought

2017-11-19T21:30:00.000+06:00

Interior view of the cave and excavation trench as of the end of the 2012 field season.
Credit: João Zilhão

Neanderthals survived at least 3,000 years longer than we thought in Southern Iberia -- what is now Spain -- long after they had died out everywhere else, according to new research published in Heliyon.

The authors of the study, an international team from Portuguese, Spanish, Catalonian, German, Austrian and Italian research institutions, say their findings suggest that the process of modern human populations absorbing Neanderthal populations through interbreeding was not a regular, gradual wave-of-advance but a "stop-and-go, punctuated, geographically uneven history."

Over more than ten years of fieldwork, the researchers excavated three new sites in southern Spain, where they discovered evidence of distinctly Neanderthal materials dating until 37,000 years ago.

"Technology from the Middle Paleolithic in Europe is exclusively associated with the Neanderthals," said Dr. João Zilhão, from the University of Barcelona and lead author of the study. "In three new excavation sites, we found Neanderthal artefacts dated to thousands of years later than anywhere else in Western Europe. Even in the adjacent regions of northern Spain and southern France the latest Neanderthal sites are all significantly older."

The Middle Paleolithic was a part of the Stone Age, and it spanned from 300,000 to 30,000 years ago. It is widely acknowledged that during this time, anatomically modern humans started to move out of Africa and assimilate coeval Eurasian populations, including Neanderthals, through interbreeding.

According to the new research, this process was not a straightforward, smooth one -- instead, it seems to have been punctuated, with different evolutionary patterns in different geographical regions.

In 2010, the team published evidence from the site of Cueva Antón in Spain that provided unambiguous evidence for symbolism among Neanderthals. Putting that evidence in context and using the latest radiometric techniques to date the site, the researchers show Cueva Antón is the most recent known Neanderthal site.

"We believe that the stop-and-go, punctuated, uneven mechanism we propose must have been the rule in human evolution, which helps explaining why Paleolithic material culture tends to form patterns of geographically extensive similarity while Paleolithic genomes tend to show complex ancestry patchworks," commented Dr. Zilhão.

The key to understanding this pattern, says Dr. Zilhão, lies in discovering and analyzing new sites, not in revisiting old ones. Although finding and excavating new sites with the latest techniques is time-consuming, he believes it is the approach that pays off.

"There is still a lot we do not know about human evolution and, especially, about the Neanderthals," said Dr. Zilhão. "Our textbook ideas about Neanderthals and modern humans have been mostly derived from finds in France, Germany and Central Europe, but during the Ice Ages these were peripheral areas: probably as much as half of the Paleolithic people who ever lived in Europe were Iberians. Ongoing research has begun to bear fruit, and I have no doubt that there is more to come."

Source: sciencedaily

Aerobic exercise increases brain size and improves neuronal health

2017-11-17T23:51:00.000+06:00

Exercise can improve memory function and brain health. Image credit: Olga.

An international team of researchers examined the effects of aerobic exercise on a region of the brain called the hippocampus, which is critical for memory and other brain functions: study published in the journal NeuroImage.

Brain health decreases with age, with the average brain shrinking by approximately 5% per decade after the age of 40.

Studies in mice and rats have consistently shown that physical exercise increases the size of the hippocampus but until now evidence in humans has been inconsistent.

In the new study, lead author Dr. Joseph Firth, a postdoctoral research fellow at the National Institute of Complementary Medicine at Western Sydney University, Australia, and colleagues reviewed 14 clinical trials which examined the brain scans of 737 people before and after aerobic exercise programs or in control conditions.

The participants’ mean age in the included trials ranged from ranged from 24 to 76 years.

Four trials recruited participants with a diagnosis of schizophrenia or other psychotic disorders, six recruited healthy older adults, whilst individual studies examined the effects of exercise of hippocampal volumes in people with depression, mild cognitive impairment, probable Alzheimer’s disease, and healthy young-middle aged adults.

The researchers examined effects of aerobic exercise, including stationary cycling, walking, and treadmill running.

The length of the interventions ranged from three to 24 months with a range of 2-5 sessions per week.

Overall, the results showed that, while exercise had no effect on total hippocampal volume, it did significantly increase the size of the left region of the hippocampus in humans.

“Our study provides some of the most definitive evidence to date on the benefits of exercise for brain health,” Dr. Firth said.

“When you exercise you produce a chemical called brain-derived neurotrophic factor, which may help to prevent age-related decline by reducing the deterioration of the brain.”

“Our data showed that, rather than actually increasing the size of the hippocampus per se, the main ‘brain benefits’ are due to aerobic exercise slowing down the deterioration in brain size. In other words, exercise can be seen as a maintenance program for the brain.”

“Along with improving regular ‘healthy’ aging, the results have implications for the prevention of aging-related neurodegenerative disorders such as Alzheimer’s and dementia — however further research is needed to establish this.”

Joseph Firth et al. 2018. Effect of aerobic exercise on hippocampal volume in humans: A systematic review and meta-analysis. NeuroImage 166: 230-238; doi: 10.1016/j.neuroimage.2017.11.007

Source: Sci-news

Mineral hematite found on Mars by NASA's curiosity rover

2017-11-17T23:41:00.002+06:00

This false-color image demonstrates how use of special filters available on Curiosity’s Mastcam camera can reveal the presence of certain minerals in target rocks. It is a composite of images taken through three ‘science’ filters chosen for making hematite stand out as exaggerated purple. Mastcam’s narrow-band filters used for this view help to increase spectral contrast, making blues bluer and reds redder, particularly with the processing used to boost contrast in each of the component images of this composite. Fine-grained hematite preferentially absorbs sunlight around in the green portion of the spectrum around 527 nm. That gives it the purple look from a combination of red and blue light reflected by the hematite and reaching the camera through the other two filters. Bright lines within the rocks are fractures filled with calcium sulfate minerals. Image credit: NASA / JPL-Caltech / MSSS.

NASA’s Curiosity rover has found spectral evidence of an iron-oxide mineral called hematite (Fe2O3) on a rock near Mount Sharp in Gale Crater, Mars.

In an area on Mars’ ‘Vera Rubin Ridge’ where the Curiosity team sought to determine whether dust coatings are hiding rocks’ hematite content, the rover found a promising target — a rock called ‘Christmas Cove.’

On September 16, 2017, during the 1,118th Martian day of Curiosity’s work on the planet, the rover’s wire-bristled brush — the Dust Removal Tool — brushed an area about 2.5 inches (6 cm) across.

Curiosity’s Mars Hand Lens Imager (MAHLI) took an image of the freshly brushed area later the same day.

“Removing dust from part of the Christmas Cove target was part of an experiment to check whether dust is subduing the apparent indications of hematite in some of the area’s bedrock,” the rover-team researchers explained.

“The brushed area’s purplish tint in an image from the MAHLI was characteristic of fine-grained hematite, an iron-oxide mineral that can provide information about ancient environmental conditions.”

“Brushing of this target also exposed details in the fine layering and bright veins within the bedrock of this part of Vera Rubin Ridge.”

Curiosity’s ChemCam instrument examined an area on the Christmas Cove and found spectral evidence of hematite. The upper-left inset of this graphic is an image from ChemCam’s Remote Micro-Imager with five labeled points that the instrument analyzed. The image covers an area about 2 inches (5 cm) wide, and the bright lines are fractures in the rock filled with calcium sulfate minerals. The five charted lines of the graphic correspond to those five points and show the spectrometer measurements of brightness at thousands of different wavelengths, from 400 nm (at the violet end of the visible-light spectrum) to 840 nm (in near-infrared). Sections of the spectrum measurements that are helpful for identifying hematite are annotated. These include a dip around 535 nm, the green-light portion of the spectrum at which fine-grained hematite tends to absorb more light and reflect less compared to other parts of the spectrum. The spectra also show maximum reflectance values near 750 nm, followed by a steep decrease in the spectral slope toward 840 nm, both of which are consistent with hematite. Image credit: CNRS.

260 million year old fossil trees found in Antarctica

2017-11-17T23:30:00.000+06:00

Dr. Erik Gulbranson working in Antarctica. Image credit: Peter Rejcek, NSF.

Paleoecologist of University of Wisconsin-Milwaukee Erik Gulbranson has found the fossil remnants of a Permian-age forest on the frozen slopes of the McIntyre Promontory in the Transantarctic Mountains.

The fossil forest dates back to the late Permian period some 260 million years ago.

“The Permian period ended 251 million years ago in history’s greatest mass extinction, as the Earth rapidly shifted from icehouse to greenhouse conditions. More than 90% of species on Earth disappeared, including the polar forests,” Dr. Gulbranson said.

“Because the Antarctic forests grew at polar latitudes where plants can’t grow today, we believe that the trees were an extremely hearty species and are trying to determine why they went extinct.”

Dr. Gulbranson and colleagues found the fossil fragments of at least 13 trees.

“This forest is a glimpse of life before the extinction, which can help us understand what caused the event. It can also give clues to how plants were different than today,” he said.

At the end of the Permian period, Antarctica was part of the supercontinent Gondwana and was warmer and more humid than it is today.

There would have been a mixture of mosses, ferns and an extinct plant called Glossopteris, and it’s likely that this forest stretched across the entirety of the supercontinent.

“The fossil forests looked different than forests today,” Dr. Gulbranson noted.

“During the Permian period, forests were a potentially low diversity assemblage of different plant types with specific functions that affected how the entire forest responded to environmental change. This is contrast to modern high-latitude forests that display greater plant diversity.”

“This plant group must have been capable of surviving and thriving in a variety of environments.”

“It’s extremely rare, even today, for a group to appear across nearly an entire hemisphere of the globe.”

But not even these robust forests survived the high carbon dioxide concentrations of the mass extinction.

The resilient plants also must have survived through the polar extremes of perpetual light and total darkness. Even in a warmer past, the polar regions would have experienced months of darkness in winter and would have gone without sunset during the summer months.

By studying the preserved tree rings, the authors found that these trees transitioned from summer activity to winter dormancy rapidly, perhaps within a month.

Modern plants make the same transition over the course of several months and also conserve water by making food during the day and resting at night.

Scientists don’t yet know how months of perpetual light would have affected the plants’ day-and-night cycles.

“There isn’t anything like that today. These trees could turn their growing cycles on and off like a light switch,” Dr. Gulbranson said.

“We know the winter shutoff happened right away, but we don’t know how active they were during the summertime and if they could force themselves into dormancy while it was still light out.”

Source: Sci-news

Mushrooms Contain Powerful Antioxidants with Anti-Aging Potential

2017-11-17T23:22:00.000+06:00

Mushrooms contain unusually high amounts of antioxidants called glutathione and ergothioneine. Image credit: Jan Plywacz.

Some mushroom species are filled with two antioxidants- glutathione and ergothioneine. Both are helpfull for anti-aging treatment.

The research paper highlighted some facts:

Glutathione levels varied >20-fold in different mushroom varieties and were highly correlated with ergothioneine levels.
Glutathione content of some mushroom species were higher than those previously found in other foods.
Mushroom species high in glutathione and ergothioneine are an excellent dietary antioxidant source.

Professor Robert Beelman, from Penn State Center for Plant and Mushroom Products for Health said “We found that mushrooms have high amounts of the ergothioneine and glutathione, both important antioxidants, and that the amounts the two compounds varied greatly between mushroom species".

“What we found is that, without a doubt, mushrooms are highest dietary source of these two antioxidants taken together, and that some types are really packed with both of them.”

When the human body uses food to produce energy, it also causes oxidative stress because some free radicals are produced.

Free radicals are oxygen atoms with unpaired electrons that cause damage to cells, proteins and even DNA as these highly reactive atoms travel through the body seeking to pair up with other electrons.

Replenishing antioxidants in the body, then, may help protect against this oxidative stress.

“There’s a theory — the free radical theory of aging — that’s been around for a long time that says when we oxidize our food to produce energy there’s a number of free radicals that are produced that are side products of that action and many of these are quite toxic,” Professor Beelman said.

“The body has mechanisms to control most of them, including ergothioneine and glutathione, but eventually enough accrue to cause damage, which has been associated with many of the diseases of aging, like cancer, coronary heart disease and Alzheimer’s.”

The amounts of ergothioneine and glutathione in mushrooms vary by species with the porcini species, a wild variety, containing the highest amount of the two compounds among the 13 species tested, the study found.

“We found that the porcini has the highest, by far, of any we tested. This species is really popular in Italy where searching for it has become a national pastime,” Professor Beelman said.

The more common mushroom types, like the white button, had less of the antioxidants, but had higher amounts than most other foods.

The amount of ergothioneine and glutathione also appear to be correlated in mushrooms. Mushrooms that are high in glutathione are also high in ergothioneine, for example.

“Cooking mushrooms does not seem to significantly affect the compounds. Ergothioneine are very heat stable,” Professor Beelman said.

Michael D. Kalaras et al. 2017. Mushrooms: A rich source of the antioxidants ergothioneine and glutathione. Food Chemistry 233: 429-433; doi: 10.1016/j.foodchem.2017.04.109

Source: Sci-news

Highly energetic cosmic explosion discovered, type never seen before

2017-11-17T23:11:00.000+06:00

Illustration of a stream of material from a star as it is being devoured by a supermassive black hole in a tidal disruption flare. Image credit: NASA / JPL-Caltech.

An extremely energetic cosmic explosion happend on a very massive star or on the environment of a supermassive black hole. A paper reporting this discovery is published in the journal Nature Astronomy.

Using telescopes on La Palma and Hawaii, the astronomers detected an explosion that was so energetic it must have originated from one of two sources: (i) an extremely massive star — up to several hundred times more massive than our Sun — exploding as a supernova, or (ii) a lower mass star that has been shredded by the ultra-strong gravitational forces close to the supermassive black hole.

The event, dubbed PS1-10adi, occurred in the center of an active galaxy called SDSS J204244.74+153032.1, some 2.4 billion light-years from Earth.

“If these explosions are tidal disruption events — where a star gets sufficiently close to a supermassive black hole’s event horizon and is shredded by the strong gravitational forces — then its properties are such that it would be a brand new type of tidal disruption event,” said lead author Dr. Erkki Kankare, from Queen’s University Belfast, UK.

“If they are supernova explosions then their properties are more extreme than we have ever observed before, and are likely connected to the central environments of the host galaxies.”

PS1-10adi. Image credit: Pan-STARRS1 / Kankare et al.

“The discovery we made has revealed explosions capable of releasing an amount of energy 10 times bigger than normal explosions,” added co-author Dr. Cosimo Inserra, from the University of Southampton, UK.

“Our data show that events like this are not very unusual and challenge our knowledge of exploding and disrupting stars.”

“At the same time, their existence provides us with important information about the extreme environment in the central, hidden, part of galaxies.”

“Now that we know what we are looking for, we are particularly excited that we will find more transients such as PS1-10adi in larger datasets from upcoming facilities,” said co-author Dr. Rubina Kotak, also from Queen’s University Belfast.

“This means that we are in a fantastic position to pin down their origin, and this will help to piece together more clues of how these events come about.”

E. Kankare et al. A population of highly energetic transient events in the centres of active galaxies. Nature Astronomy, published online November 13, 2017; doi: 10.1038/s41550-017-0290-2

Source: sci-news

Black holes are colliding again, it's fifth time

2017-11-17T18:44:00.004+06:00

Illustration of Colliding black holes

Mark Garlick/Science Photo Library/Alamy Stock Photo

Black holes are colliding regularly. Scientist could observe them from earth. It's fifth time black holes colliding is observed from earth.

For a fifth time, scientists have reported the detection of two colliding black holes via their gravitational waves, tiny vibrations that warp the fabric of spacetime. Unlike previous gravitational wave detections, which were heralded with news conferences often featuring panels of scientists squinting at journalists under bright lights, this was a low-key announcement. The event, caught on June 8, 2017, by the Advanced Laser Interferometer Gravitational-Wave Observatory, LIGO, was unceremoniously unveiled in a paper published online November 15 at arXiv.org.

With masses 7 and 12 times that of the sun, the pair of black holes was the lightest LIGO has spotted so far. The lack of fanfare over the detection signals a shift. Scientists are now aiming to collect data from many black hole crashes. That data can be analyzed to answer questions about the population as a whole, such as how two black holes get paired up in the first place.

Source: Sciencenews

Nobody born as believer, it comes from society

2017-11-17T18:16:00.001+06:00

Religions

Image credit: thegodmurders

A new research at "The universities of Coventry and Oxford" relieved that religious beliefs are not comes from intuition or rational thinking.

We thought that people who hold strong religious beliefs are more intuitive and less analytical, and when a man think more analytically his or her religious beliefs decrease.

But new research, by academics from Coventry University’s Centre for Advances in Behavioural Science and neuroscientists and philosophers at Oxford University, suggests that is not the case, and that people are not ‘born believers’.

The study on pilgrims taking part in the famous Camino de Santiago and a brain stimulation experiment – found no link between intuitive or analytical thinking, or cognitive inhibition (an ability to suppress unwanted thoughts and actions), and supernatural beliefs.

Instead, the academics conclude that other factors, such as upbringing and socio-cultural processes, are more likely to play a greater role in religious beliefs.

The study – published in Scientific Reports — was the first to challenge a growing trend among cognitive psychologists over the past 20 years that has attempted to show that believing in the supernatural is something that comes to us ‘naturally’ or intuitively.

The team started by carrying out an investigation on one of the largest pilgrimage routes in the world – the Camino de Santiago de Compostela, in northern Spain.

They asked pilgrims about the strength of their beliefs and the length of time spent on the pilgrimage and assessed their levels of intuitive thinking with a probability task, where participants had to decide between a logical and a ‘gut feeling’ choice. The results suggested no link between strength of supernatural belief and intuition.

In a second study, where they used mathematical puzzles to increase intuition, they also found no link between levels of intuitive thinking and supernatural belief.

In the last part of their research they used brain stimulation to increase levels of cognitive inhibition, which is thought to regulate analytical thinking.

This involved running a painless electrical current between two electrodes placed on the participant’s scalp, to activate the right inferior frontal gyrus, a part of the brain that controls inhibitory control. A previous brain-imaging study had shown that atheists used this area of the brain more when they wanted to suppress supernatural ideas.

The results showed that while this brain stimulation increased levels of cognitive inhibition, it did not change levels of supernatural belief, suggesting there is no direct link between cognitive inhibition and supernatural belief.

The academics say that it is “premature” to explain belief in gods as intuitive or natural.

Instead, they say their research supports a theory that religion is a nurture-based process and develops because of socio-cultural processes, including upbringing and education.

Leading author Miguel Farias said:

    “What drives our belief in gods – intuition or reason; heart or head? There has been a long debate on this matter but our studies have challenged the theory that being a religious believer is determined by how much individuals rely on intuitive or analytical thinking.
    We don’t think people are ‘born believers’ in the same way we inevitably learn a language at an early age. The available sociological and historical data show that what we believe in is mainly based on social and educational factors, and not on cognitive styles, such as intuitive/analytical thinking.
    Religious belief is most likely rooted in culture rather than in some primitive gut intuition.”

Source: Why do we believe in gods? Religious belief not linked to intuition or rational thinking, new research suggests

Aging will be visible if anyone drink and smoke heavy

2017-11-17T15:32:00.002+06:00

Aging concept, young and old comparison (stock image).
Credit: © blackday / Fotolia

Recently a research has published n the "Journal of Epidemiology & Community Health" which says that heavy drinking and smoking are linked to visible signs of physical aging, and looking older than one's years.

Light to moderate drinking was not associated with biological aging, the findings showed.

But nor was it linked to the slowing of the visible aging process as there was no difference in the prevalence of the signs of aging between light to moderate drinkers and non-drinkers, the researchers point out.

They base their findings on information from more than 11,500 adults, whose heart health and visible aging signs were tracked for an average of 11.5 years as part of the Copenhagen City Heart Study.

This study, which began in 1976, has been monitoring a random sample of Danish people over the age of 20 living in the Copenhagen area in 1981-3, 1991-4, and in 2001-3.

Before each of the clinic visits, participants were quizzed about their lifestyle and general health and asked to state how much they drank and smoked.

And they were checked for four signs of aging that have previously been linked to a heightened risk of cardiovascular ill health and/or death.

These were: earlobe creases; a greyish opaque coloured ring or arc around the peripheral cornea of both eyes (arcus corneae); yellow-orange plaques on the eyelids (xanthelasmata); and male pattern baldness (receding hairline or a bald patch on the top of the head).

The average age of the participants was 51, but ranged from 21 to 86 among the women, and from 21 to 93 among the men. Average alcohol consumption was 2.6 drinks/week for women and 11.4 for men. Just over half the women (57%) and around two thirds of the men (67%) were current smokers.

Arcus coneae was the most common sign of aging among both sexes, with a prevalence of 60 per cent among men over 70 and among women over 80. The least common sign was xanthelasmata, with a prevalence of 5 per cent among men and women over 50. A receding hairline was common among men, with 80 per cent of those over the age of 40 affected.

Analysis of drinking and smoking patterns revealed a consistently heightened risk of looking older than one's true age and developing arcus corneae, earlobe creases, and xanthelasmata among those who smoked and drank heavily.

For example, compared with a weekly alcohol intake of up to 7 drinks, a tally of 28 or more was associated with a 33 per cent heightened risk of arcus coneae among the women, and a 35 per cent heightened risk among men who knocked back 35 or more drinks every week.

Similarly, compared with not smoking, smoking one pack of 20 cigarettes daily for between 15 and 30 years was associated with a 41 per cent heightened risk among women and a 12 per cent heightened risk among men.

The occurrence of the visible signs of aging was no different among light to moderate drinkers than it was among non-drinkers, the analysis showed.

Male pattern baldness was not consistently associated with heavy drinking or smoking, possibly because it is strongly influenced by genes and circulating levels of male hormones (androgens), suggest the researchers.

This is an observational study so no firm conclusions can be drawn about cause and effect, particularly as the data on smoking and drinking relied on personal recall, which is subject to bias.

And while the researchers took account of a range of potentially influential factors, they were unable to take account of stress, which is associated both with cardiovascular disease risk and smoking and heavier drinking.

Nevertheless, they conclude: "This is the first prospective study to show that alcohol and smoking are associated with the development of visible age-related signs and thus generally looking older than one's actual age....This may reflect that heavy drinking and smoking increases general aging of the body."

Source: Anne L Schou et al. Alcohol consumption, smoking and development of visible age-related signs: a prospective cohort study. Journal of Epidemiology & Community Health, November 2017 DOI: 10.1136/jech-2016-208568

Biologist Modifies Theory Of Cells' Engines

2008-12-25T21:59:00.000+06:00

Biologists have known for decades that cells use tiny molecular motors to move chromosomes, mitochondria, and many other organelles within the cell, but no one has been able to understand what "steers" these engines to their destinations. Now, researchers at the University of Rochester have shed new light on how cells accomplish this feat, and the results may eventually lead to new approaches to fighting pathogens and neurological diseases.

Michael Welte, associate professor of biology, shows in a paper published in the December 11 issue of Cell that the mechanisms that control the molecular motors are quite different from what biologists have previously believed. Before these findings, scientists assumed that the number of motors attached to an organelle determined how far and fast the organelle could travel, but Welte and colleagues have discovered that it is not the number of motors, but yet-to-be-discovered molecules that are likely the master regulators.

"The fact that motor number has nothing to do with regulating transport is extremely surprising, and somewhat unsettling to people working in vitro," says Welte. "It says we're really missing something when we study these motors only in the test tube instead of in a living cell."

Intracellular transport is crucial to a cell's health, says Welte. For instance, during cell division, one copy of each of the cell's chromosomes migrates to one side of the cell while the other copy moves to the other side. If this movement is disturbed, it could cause an imbalance of chromosomes in the daughter cells, which might die or become cancerous. Similarly, neurons, some of which are as much as three feet in length, manufacture proteins and organelles at one end and then must move that precious cargo all the way to the far end where they'll be used. This is an enormous task, says Welte, and defects in this transport are thought to cause a number of neurological diseases.

Given the difficulty of investigating these tiny motors acting within the cell, biologists have performed basic experiments on them outside of the cell in a carefully controlled environment. This led them to believe that the speed and distance an organelle could be transported depended on how many motors were pulling it, says Welte. Thus, the scientists reasoned, perhaps the cell simply attaches the right number of motors to an organelle to send it the right distance. Although this "multi-motor" hypothesis is very simple and elegant, says Welte, whether it actually holds true within living cells had never been tested.

Welte's graduate student, Susan Tran, decided to perform that test. She created fruit-fly eggs lacking a type of molecular motor called kinesin and found that certain organelles stopped moving—strong evidence that kinesin is responsible for their transport. Tran then made another type of mutant eggs, this time ones that produced only about half the number of kinesin motors of a regular egg. In both types of eggs, organelles were transported with the same speed and the same distance.

Welte needed to know if this equality was because the normal egg was simply utilizing only half the available kinesin motors, or if some master regulator was controlling the organelle's progress, regardless of the number of motors moving it. To do this, Welte turned to Steven Gross, associate professor of developmental and cell biology at the University of California. Gross' group uses an apparatus called "optical tweezers" that employs laser light to measure the tiny forces the motors generate. The team found that organelles in regular cells are pulled with twice the force of Tran's mutant, low-kinesin cells.

"That clinched it for us," says Welte. "Yes, there are multiple motors moving organelles around, but exactly how many doesn't matter. There is something else in the cell that's controlling all the motors. That opens up a big area for research—find what's driving these motors and maybe we can control them all by controlling one thing."

Welte and his team are now looking at where in the cell this signal comes from and how it influence the motors. Although Welte's team studied fruit fly eggs, the motors moving the organelles are present in all animals and employed for many tasks, including transport in human neurons.

Welte also points out that viruses, including HIV, make use of the same kind of motors to move about the cell, first to get from the site of penetration to the nucleus, where they multiply, and then to get progeny viruses back to the cell surface. If Welte and others can figure out how cells normally control these motors, it may be possible to prevent HIV from taking control of the motors and thus to keep it, and other intracellular pathogens, at the edge of the cell where they can do little harm.

This research was funded by the National Institutes of Health, and includes researchers from the University of Rochester, the University of California Irvine, and University of Texas at Austin.
Adapted from materials provided by University of Rochester.
ScienceDaily

Mathematical Model Gives Clearer Picture Of Physics Of Cells, Organelles

2008-12-25T21:56:00.000+06:00

Cells are filled with membrane-bound organelles like the nucleus, mitochondria and endoplasmic reticula. Over the years, scientists have made much progress in understanding the biomolecular details of how these organelles function within cells, but understanding the actual physical forces that maintain the structures of these organelles' membranes continues to be a challenge.

Now, UCLA Henry Samueli School of Engineering and Applied Science researcher William Klug and colleagues from the California Institute of Technology and the Whitehead Institute for Biomedical Research in Massachusetts have devised a mathematical procedure for accurately predicting the three-dimensional forces involved in creating and maintaining certain organelle membranes.

Their study, which appears Dec. 8 in Proceedings of the National Academy of Sciences and is currently available online, could potentially shed light on the life cycles of membrane-bound viruses such as HIV.

"The study is exciting because it provides a roadmap for ways we can do predictive computational science," said Klug, an assistant professor of mechanical and aerospace engineering. "The mathematical model is able to provide us with a quantitative understanding of the physics of cells that is essentially impossible to obtain directly by experiment."

To understand the researchers' mathematical description of how forces can lead to deformations in a membrane, one can consider the simple concept of a bathroom scale.

"When you step on a scale, a small spring in the scale defines how heavy you are or what force is being applied to the scale," said study co-author Paul Wiggins, a fellow at the Whitehead Institute. "Similarly, with membranes, springs or forces cause them to bend. In a sense, we wanted to see if we could play the same game with the organelles of a cell — to take the observed structure and see if we can predict what forces are applied to give rise to the structure and essentially hold the structure together."

The team used an artificial biomembrane to investigate the dynamic forces that act on a cell's membrane and organelles. With optical tweezers — a scientific instrument that uses a focused laser beam to provide an attractive or repulsive force — they were able to trap and move parts of the cell. This enabled the researchers to exert known forces in different ways, giving them an opportunity to analyze both the response of the membranes when their structures were changed dramatically and to validate their mathematical procedure for predicting forces based on the deformed shapes of the membranes.

"We have this geometry, so what are the forces?" said Klug. "It seems straightforward if you write it out mathematically but in practice, actually measuring the forces reliably where you can quantify the error is really tricky."

The researchers believe that understanding the forces and mechanisms that are responsible for maintaining the geometries of the organelles will help them uncover the crucial factors that lead to changes or malfunctions in organelles.

"When cells undergo oxygen damage, that usually leads to a change in the structure of the mitochondria — the specialized organelles often referred to as the powerhouses of cells," Wiggins said. "There is a close link between the ability of the mitochondria to function and its structure. By relating structure to force, we can uncover the crucial factors that lead to the change in the structure of the mitochondria and other organelles as well."

Membrane-bound viruses like HIV infect cells and then replicate and break from the cells by budding. This budding process eventually uses up the cell membrane and kills it.

"The forces that lead to the process of budding are essentially unknown," Klug said. "Researchers have looked at the image data of HIV in different stages of budding to try to understand the forces that lead up to it. If we can eventually understand what those forces are, we might be able to come up with a way to disrupt the viral assembly process. And that's a different strategy than what is being done today to treat retroviruses and HIV in particular."

Adapted from materials provided by University of California - Los Angeles.
ScienceDaily

Time Running Out On Coral Reefs As Climate Change Becomes Increasing Threat

2008-12-25T21:53:00.000+06:00

Located off the northeastern coast of Australia, the Great Barrier Reef is the largest coral reef system in the world. Increasing pressures from climate change will reach a tipping point in less than a decade triggering a significant decline in the health of the planet's coral reef ecosystems according to the findings in an international report. (Credit: iStockphoto)

Increasing pressures from climate change will reach a tipping point in less than a decade triggering a significant decline in the health of the planet's coral reef ecosystems according to the findings in an international report.

Released by the Global Coral Reef Monitoring Network and the International Coral Reef Initiative, international governmental and scientific partnerships, "Status of Coral Reefs of the World: 2008" provides both good and bad news while sounding the call for urgent global action to respond to climate change.

Coral reefs continue to be threatened from direct human activities of pollution and over-fishing, but now the threat of climate change is being recognized as the major threat to the future of reefs around the world. One fifth of the Earth's coral reefs have disappeared since 1950, and a NOAA authored report issued in July states that more that that nearly half of U.S. coral reef ecosystems are considered to be in "poor" or "fair" condition.

"Unless the world gets serious about reducing greenhouse gas emissions in the next few years, it is likely there will be massive bleaching and deaths of corals around the world," notes the report's lead editor and global coral authority Clive Wilkinson who coordinates the Global Coral Monitoring Network in Australia. "This will have significant impacts on the lives of the people in developing countries who are dependent on reefs for food, for tourism, and for protecting the land they live on."

This status report was put together from 370 contributors in 96 countries and states and is the most authoritative report on the world's coral reefs. The report presents regional assessments of the health coral reef ecosystems found throughout the world, the threats they face, and recommendations for action. A new feature of the 2008 reporting is publication of a separate report, "Socioeconomic Conditions along the World's Tropical Coasts: 2008," detailing socioeconomic data on how people use coral reefs in 27 developing tropical coastal countries.

The status report includes satellite date from NOAA's Coral Reef Watch project which measures stress to reefs from temperature globally and resulting bleaching. NOAA recently started tracking ocean acidification changes in the Caribbean.

Frequent or long-term bleaching kills or severely weakens corals, leaving them more vulnerable to disease, and resulting in a sea bottom covered with algae and sponges that may eventually smother remaining coral. Acidification is a growing threat that could imperil the ability of corals to build their skeletons. A number of recent studies demonstrate that ocean acidification is likely to harm coral reefs by slowing coral growth and making reefs more vulnerable to erosion and storms.

In good news the report, which is issued every four years, found that there was major recovery of reefs in the Indian Ocean and western Pacific from climate change induced bleaching events in 1998 - especially those reefs that were in protected areas. Other reefs cited as being in healthy condition included Australian reefs in general, most notably the Great Barrier Reef, the remote reef systems of the Pacific and Indian Ocean that suffer little human impacts and some small areas of the Caribbean.

The report also acknowledges that increased awareness such as that promoted by 2008 being designated "International Year of the Reef" is beginning to have an impact pointing to a series of major conservation initiatives that have been announced in recent years including the Coral Triangle Initiative in Asia, the Micronesia and Caribbean Challenges, and the creation of the two largest marine protected areas in the world: in the Phoenix Islands of Kiribati and the U.S. Papahanaumokuakea Marine National Monument.

In addition to climate change, negative impacts to corals in the past four years included the Indian Ocean tsunami, hurricane damage which combined with bleaching has endangered wide ranges of Caribbean coral reefs, and increasing human activity pressures including pollution, development, deforestation and overfishing in East Africa, South Asia, Southeast Asia, populated areas of the Pacific and Caribbean. One particular threat is the increase in "bomb" and cyanide fishing in Asia and in Tanzania.

The assessment includes detailed recommendations to preserve and better manage reef ecosystems. Human pollution and fishing pressures have to be reduced while the development of sustainable tourism activities can protect the reefs while stimulating economic growth. The report also encourages increased use of marine protected areas as a means of ensuring reefs can continue to protect important fish nursery areas and serve as reservoirs of marine biodiversity.

The Global Coral Reef Monitoring Network receives support from governmental and non-governmental organizations including the U.S. Department of State, NOAA (the National Oceanic and Atmospheric Administration), the World Bank and the WWF (World Wildlife Fund) to publish this survey of the health of the world's coral reefs and diagnoses solutions for halting and reversing their decline.

Adapted from materials provided by The Global Coral Reef Monitoring Network, via EurekAlert!, a service of AAAS.
ScienceDaily

Fraud In Science: How Prevalent Is It And What Can Be Done?

2008-12-25T21:51:00.000+06:00

Public confidence in the honesty of scientists is being harmed by a small minority of researchers who behave badly, a conference recently heard. European research organisations agreed to work more closely to tackle the problem of fraud and other misconduct in science.

The meeting in Madrid on 17-18 November was organised by the newly formed Research Integrity Forum of the European Science Foundation (ESF) in collaboration with the Spanish National Research Council (CSIC). It continued work set in motion by the first world conference on research integrity held in Lisbon in September 2007.

Fraud in science includes inventing data (fabrication), manipulating data to produce an unjustified result (falsification) or presenting the work of other researchers as one's own (plagiarism).

There is little hard evidence of the extent of the problem but various estimates suggest that between 0.1% and 1% of researchers commit fraud and perhaps as many as 10% to 50% engage in questionable practices. Most of these are relatively minor, said Dr John Marks, Director of Science and Strategy at ESF, "but if people get away with it and if no-one says anything about it, it might invite bigger issues of misconduct." He said that opinion polls showed that trust in scientists is still high "but that trust is easily lost by high profile cases of misconduct and that is why we are so concerned."

A survey by ESF earlier this identified 18 European countries that had put in place codes of conduct for good practice in research but they varied greatly in how they dealt with suspected cases. Many have set up research integrity offices to promote good practice and discourage misconduct.

No European country has yet followed the lead of the US National Science Foundation which, along with other federal agencies, has statutory powers to investigate allegations of fraud including power to subpoena evidence. Dr Peggy Fischer, of the NSF's Office of Inspector General, described how offenders can be required to take a course in scientific ethics or, in the most serious cases, banned from receiving any federal research funding for up to five years.

Systems in Europe tend to be more consensual and rely more on the self-governance of the scientific community. Professor Eero Vuorio, chair of the National Advisory Board on Research Ethics, said that all of Finland's universities and polytechnics and most research funding bodies had signed up to a national code of good scientific practice. Allegations of misconduct are investigated by individual institutions to an agreed procedure with the help of outside experts. Sanctions are in the hands of employers.

Although most countries agree on the core definition of what constitutes misconduct, they differ in how they regard other unethical behaviour and how they deal with it. The meeting heard reports on the situation in the United Kingdom, Portugal, the Czech Republic and France.

With much research now being done in international collaborations, problems can arise when fraud is committed within a cross-border partnership and there are no agreed rules on how cases are to be investigated and how sanctions can be imposed.

A move towards a common approach has been proposed by the Global Science Forum of the OECD, which would require potential collaborators to agree on what to do in cases of suspected misconduct. "When you're doing your collaborative planning you need to recognise that things can go wrong," said co-chair of the forum, Christine Boesz of NSF. She acknowledged that such an idea was new and was meeting resistance from some researchers.

The meeting also discussed the role of universities, national academies, international scientific bodies and scientific journals in promoting research integrity and heard of a project to compile a database of research papers known to be tainted by fraud. A proposal for a global clearinghouse to promote research integrity was also presented.

Members of the forum agreed to exchange information and good practice, to develop a code of conduct that could be used as a template for national codes, to develop a checklist to assist ESF members in setting up national and institutional structures to promote good practice and deal with misconduct, and to promote further research on the extent of misconduct.

Co-organiser Professor Juan José de Damborenea of CSIC told the meeting: "Society requires science and researchers to solve the problems that concern all of us. In general, public opinion has a good image of the honesty of scientists. We cannot allow it to be lost."

Adapted from materials provided by European Science Foundation.
ScienceDaily

4,000-year-old Amber Necklace Has Been Unearthed In England

2008-12-25T21:49:00.001+06:00

A 4,000-year-old amber necklace has been unearthed in England. (Credit: Image courtesy of University of Manchester)

A 4,000-year-old amber necklace has been unearthed in England. The rare find was unearthed from a stone-lined grave – known as a Cist - excavated by the team from The University of Manchester Field Archaeology Centre and Mellor Archaeological Trust.

It is the first time a necklace of this kind from the early Bronze Age has been found in north west England.

Peter Noble from The University of Manchester said: “An amber necklace of this sort was one of the most important ways that people of the early Bronze Age could display their power and influence.

“The fact that it has been found in the north west of England is pretty amazing and extremely rare.”

Dozens of different sized pierced amber beads are linked together on a length of fibre to form the beautiful artifact.

It was discovered by Vicky Nash from of the Mellor Archaeological Trust.

Peter Noble, who directed the dig added: “The necklace was made of amber – which is not found in this region.

“In fact, the nearest source is in the Baltic so we’re bound to ask, how did it get here and who brought it?”

Adapted from materials provided by University of Manchester.
ScienceDaily

Potential Links Between Breast Density And Breast Cancer Risk

2008-12-25T21:48:00.000+06:00

Having dense breasts - areas that show up light on a mammogram - is strongly associated with increased breast cancer risk, but "why" remains to be answered. Now, by examining dense and non-dense tissue taken from the breasts of healthy volunteers, researchers from Mayo Clinic have found several potential links.

In two studies being presented simultaneously in poster form at the Cancer Therapy & Research Center-American Association for Cancer Research (CTRC-AACR) San Antonio Breast Cancer Symposium, the researchers report that dense breast tissue contains more cells believed to give rise to breast cancer, compared to non-dense tissue. "We found a dramatic difference in tissue composition between dense and non-dense tissue in the breast," says Karthik Ghosh, M.D., a Mayo Clinic breast cancer researcher and physician who led one study.

In a second study, researchers also found that dense breast tissue has more aromatase enzyme than non-dense tissue. This is significant because aromatase helps convert androgen hormones into estrogen, and estrogen is important in breast cancer development, says that study's lead investigator, Celine Vachon, Ph.D.

"If aromatase is differentially expressed in dense and non-dense breast tissue, this could provide one mechanism by which density may increase breast cancer risk," Dr. Vachon says.

The researchers say these findings are unique because these studies are the first to examine areas of both dense and non-dense tissue taken from the same breast in healthy volunteers. Examination of healthy women is important, Dr. Ghosh says, because most prior studies of breast density have looked at tissue taken from women with known breast disease.

Sixty women, age 40 to 85, allowed Mayo Clinic researchers to take eight core-needle biopsies from their breasts; none had a history of breast cancer.

Dr. Ghosh and her team examined the biopsies to determine the percentage of epithelium tissue, stroma, and fat content in each. The epithelium is primarily composed of milk glands and ductal cells, and stroma is the connective tissue that supports epithelial cells. Dr. Vachon and her colleagues looked at aromatase expression within cells in both dense and non-dense tissue.

Results are now available from more than half of the participants who donated biopsy tissue. Dr. Ghosh found that areas of density contained much more epithelium (6 percent) and stroma (64 percent) and much less fat (30 percent), compared to non-dense tissue that contained less than 1 percent epithelium, about 20 percent stroma, and almost 80 percent fat. "This shows us that both the epithelium and stroma contribute to density, and suggests that the large difference in stroma content in dense breast tissue may play a significant role in breast cancer risk," Dr. Ghosh says.

She also looked at lobular involution, a decrease in the size and number of milk ducts that has been associated with decreased breast cancer risk, and found that 85 percent of non-dense tissue had complete involution compared to 35 percent of dense tissue.

Dr. Vachon and her team examined expression of aromatase in the biopsy samples and found that the stromal cells in dense breast tissue had more aromatase and intensity of expression in dense tissue, compared to non-dense. They say these findings may help explain why women with greater proportion of dense breast tissue are at greater risk for breast cancer than women with little or no density.

"These are initial findings from one of the first attempts to study breast density at the level of healthy tissue. It doesn't explain everything yet, but is providing really valuable insights," says Dr. Ghosh, who established the patient resource for both studies.

Drs. Ghosh and Vachon are finishing their analysis of the initial 60 volunteers, and they are also enrolling more participants in order to validate and expand their findings. "No one knows why density increases breast cancer risk, but we are attempting to connect the dots," Dr. Vachon says.

These studies were funded by the Mayo Clinic Breast Cancer Specialized Programs of Research Excellence (SPORE) grant, and a National Institutes of Health (NIH) career development award.
Adapted from materials provided by Mayo Clinic.
ScienceDaily

Why Climbers Die On Mount Everest

2008-12-25T21:46:00.000+06:00

Mountaineers climbing Mount Everest. (Credit: iStockphoto/Sandeep Subba)

An international research team led by Massachusetts General Hospital (MGH) investigators has conducted the first detailed analysis of deaths during expeditions to the summit of Mt. Everest. They found that most deaths occur during descents from the summit in the so-called "death zone" above 8,000 meters and also identified factors that appear to be associated with a greater risk of death, particularly symptoms of high-altitude cerebral edema.

"We know that climbing Everest is dangerous, but exactly how and why people have died had not been studied," says Paul Firth, MB, ChB, of the MGH Department of Anesthesia, who led the study "It had been assumed that avalanches and falling ice – particularly in the Khumbu Icefall on the Nepal route – were the leading causes of death and that high-altitude pulmonary edema would be a common problem at such extreme altitude. But our results do not support either assumption."

Thousands of climbers have attempted to reach the summit of 8,850-meter (29,000-foot) Mount Everest since the 1920s. In order to examine the circumstances surrounding all deaths on Everest expeditions, the research team – which included investigators from three British hospitals and the University of Toronto – reviewed available expedition records including the Himalayan Database, a compilation of information from all expeditions to 300 major peaks in the world's highest range. Of a total of reported 212 deaths on Everest from 1921 to 2006, 192 occurred above Base Camp, the last encampment before technical (roped) climbing begins.

Firth and three physician co-authors – all experienced Himalayan mountaineers with expertise in managing high-altitude illness – reviewed records for all deaths and classified them according to available information. More detailed analysis was conducted on deaths occurring above 8,000 meters during the past 25 years. Deaths were categorized as traumatic, from falls or external hazards such as avalanches; nontraumatic, from high-altitude illness, hypothermia or other medical causes; or as disappearances. Expedition participants were classified as either 'climbers,' individuals from outside the Himalayan region, or 'sherpas' – high-altitude porters, most of them ethnic Sherpas or Tibetans, hired to transport equipment and otherwise assist the climbers.

The overall mortality rate for Everest mountaineers during the entire 86-year period was 1.3 percent; the rate among climbers was 1.6 percent and the rate among sherpas was 1.1 percent. During the past 25 years, a period during which a greater percentage of moutaineers climbed above 8,000 meters, the death rate for non-Himalayan climbers descending via the longer Tibetan northeast ridge was 3.4 percent, while on the shorter Nepal route it was 2.5 percent.

Factors most associated with the risk of death were excessive fatigue, a tendency to fall behind other climbers and arriving at the summit later in the day. Many of those who died developed symptoms such as confusion, a loss of physical coordination and unconsciousness, which suggest high-altitude cerebral edema, a swelling of the brain that results from leakage of cerebral blood vessels. Symptoms of high-altitude pulmonary edema, which is involved in most high-altitude-related deaths, were suprisingly rare.

"High-altitude cerebral edema symptoms were common among those that died, but signs of pulmonary edema, or excessive fluid in the lungs, were unusual" Firth says. "We also were surprised at how few people died due to avalanches and ice falls in recent years – those usually happen at lower altitudes, and overwhelmingly people died during summit bids above 8,000 feet – and that during descents, the mortality rate for climbers was six time that of sherpas."

While the reduced mortality rate among sherpas during descent suggests that taking time to acclimatize to high altitude could improve climber survival, Firth notes that many other factors may be involved. "Most of the sherpas are born and live their lives at high altitudes, and the competitive process for expedition employment probably selects those who are best adapted to and most skilled for the work. So the ability of lowlanders to acclimate to these very high altitudes needs further investigation."

During a 2004 Norwegian-American expedition from the north side of Everest led by Firth, equipment problems led the team to turn around at 8,300 meters, return to 7,900 meters and pool their oxygen supply. Half of the team successfully re-attempted the summit and returned safely, including Randi Skuag, the first Norwegian woman to climb Everest. Seven other climbers from other teams that year were not so fortunate – all dying above 8,000 meters, most while descending from the summit.

"The majority of those who have died on Everest were in the prime of their lives, with families and friends left bereft," stresses Firth, who is an instructor in Anaesthesia at Harvard Medical School. "Mountaineering is for fun; it's not worth dying or leaving others there to die. Appropriate caution is the hallmark of the elite mountaineer – the mountain will always be there next year."

The report, which will appear the December 20/27 issue of the British Medical Journal has been released online. The senior author of the British Medical Journal report is Richard Salisbury, who created and maintains the Himalayan Database. The other physician reviewers are Jeremy Windsor, MD, the Heart Hospital, London; Andrew Sutherland, MD, Radcliffe Hospital, Oxford; and Christopher Imray, MD, University Hospital, Coventry, all in the U.K. Additional co-authors are Hui Zheng, PhD, MGH Department of Medicine; G.W. Kent Moore, PhD, and John Semple, MD, University of Toronto; and Robert Roach, PhD, University of Colorado. The study was supported by the MGH Department of Anesthesia and Critical Care.

Adapted from materials provided by Massachusetts General Hospital, via EurekAlert!, a service of AAAS.
ScienceDaily

Toothbrushing Can Prevent Hospital-borne Pneumonia

2008-12-25T21:43:00.001+06:00

Ordinary tooth brushing could help prevent ventilator-associated pneumonia, new research shows. (Credit: iStockphoto/Michael Gatewood)

Hospital-borne infections are a serious risk of a long-term hospital stay, and ventilator-associated pneumonia (VAP), a lung infection that develops in about 15% of all people who are ventilated, is among the most dangerous. With weakened immune systems and a higher resistance to antibiotics, patients who rely on a mechanical ventilator can easily develop serious infections — as 26,000 Americans do every year.

Thanks to a proven new clinical approach developed by Tel Aviv University nurses, though, there is a new tool for stopping the onset of VAP in hospitals.

This new high-tech tool? An ordinary toothbrush.

Three Times a Day Keeps Pneumonia Away

“Pneumonia is a big problem in hospitals everywhere, even in the developed world,” says Nurse Ofra Raanan, the chief researcher in the new study and a lecturer at Tel Aviv University’s Department of Nursing. “Patients who are intubated can be contaminated with pneumonia only 2 or 3 days after the tube is put in place. But pneumonia can be effectively prevented if the right measures are taken.”

Raanan, who works at the Sheba Academic School of Nursing at The Chaim Sheba Medical Center, collaborated with a team of nurses at major medical centers around Israel. The nurses found that if patients — even unconscious ones — have their teeth brushed three times a day, the onset of pneumonia can be reduced by as much as 50%.

A Pioneering Study with Measurable Effects

It’s difficult to quantify the effects precisely, the researchers say. “While the research shows a definite improvement in reducing the incidence of hospital-borne pneumonia, it’s hard to say by exactly how much toothbrushing prevents VAP,” says Raanan, but the published evidence shows a direct correlation for intubated patients.

“Sometimes, however, doctors and nurses do everything right and the patient still gets pneumonia. But this approach will certainly improve the odds for survival.”

Normally, the teeth and oral cavity in a healthy mouth maintain a colony of otherwise harmless bacteria. Infection takes root when a breathing tube allows free passage of the “good” bacteria into the lower parts of the lung. The bacteria travel in small water droplets through the tube and colonize the lung. Once there, the bacteria take advantage of a patient’s weakened immune system and multiply. A regular toothbrushing kills the growth and subsequent spread of the bacterium that leads to VAP.

Augmenting the Preventative Routine

There are additional steps for preventing the onset of VAP. Today, nurses typically use a mechanical suction device to remove secretions from the mouth and throat. They also put patients in a seated position and change the position every few hours. Toothbrushing, say Tel Aviv University nurses, should be added to the routine.

Although nurses in some American hospitals already practice toothbrushing on ventilated patients, these new results may convince medical centers around the world to invest more resources in this routine practice, thereby saving lives.

The research and recommendations are scheduled for publication in a leading nursing journal.

Adapted from materials provided by Tel Aviv University.
ScienceDaily

Jupiter's Moon Europa Does The Wave To Generate Heat

2008-12-25T21:41:00.000+06:00

If the moon Europa is tilted on its axis even slightly as it orbits the giant planet Jupiter, then Jupiter's gravitational pull could be creating powerful waves in Europa's ocean. (Credit: NASA)

One of the moons in our solar system that scientists think has the potential to harbor life may have a far more dynamic ocean than previously thought.

If the moon Europa is tilted on its axis even slightly as it orbits the giant planet Jupiter, then Jupiter's gravitational pull could be creating powerful waves in Europa's ocean, according to Robert Tyler, an oceanographer with the University of Washington's Applied Physics Laboratory and author of a letter in the Dec. 11 Nature. As those waves dissipate, they would give off significant heat energy.

Depending on the amount of tilt, the heat generated by the ocean flow could be 100 to thousands of times greater than the heat generated by the flexing of Europa's rocky core in response to gravitational pull from Jupiter and the other moons circling that planet.

That's the current assumption – that oceans on moons are heated mainly by this flexing of their cores. In the case of Europa, it also has been thought that the thick ice covering its ocean probably generates some heat as two sides of cracked ice rub together in response to gravitational pull.

"If my work is correct then the heat source for Europa's ocean is the ocean itself rather than what's above or below it," Tyler says. "And we must form a new vision of the ocean habitat that involves strong ocean flow rather than the previously assumed sluggish flows."

Both are important considerations if exploratory missions are ever sent to Europa in search of life. Europa, which is slightly smaller than Earth's moon, is one of Jupiter's 63 moons. With surface temperatures as cold as minus 260 degrees Fahrenheit, Europa's surface is covered with a thick layer of ice. There is evidence of a liquid ocean beneath the ice and, if there is volcanic activity on the sea floor, this could be a recipe for generating microorganisms that live without sunlight, perhaps like the microorganisms found at hydrothermal vents and other places on Earth.

Many planets and moons are known to be tilted within their orbital plane. The Earth, for example, has an axial tilt of about 23 degrees. It's why the northern and southern hemispheres have different seasons, depending on whether they are tilted more toward or away from the sun.

Previous theoretical calculations expected Europa to have an axial tilt of at least 0.1 degrees. It hasn't been measured and could be bigger than this. But even at this minimum value the tidal flow on Europa using Tyler's new calculation is quite strong – some 10 centimeters a second – and enough to cause significant heating.

The new calculation differs from previous ones in that it allows a more realistic dynamic response of the ocean to the tidal forces.

His assumptions and calculations led him to say that he thinks this kind of wave action could be the dominant heat source in the oceans of Europa and other moons.

"But this proposal is a relatively new contender – so let's see how it does," he says. Tyler is the sole author of the letter in Nature. His work was supported by NASA's Outer Planets Research program.

Adapted from materials provided by University of Washington.
ScienceDaily

Astrophysicists Aim To Recreate Stars In The Lab

2008-12-25T21:40:00.000+06:00

Astronomers are recruiting the physics laboratory to unravel the high energy processes involved in formation of stars and other critical processes within the universe. Experiments with high energy radiation and plasmas in the laboratory involving temperatures and magnetic fields over a million times greater than normally encountered on earth are also producing spin off benefits for important applications, notably in the drive towards nuclear fusion as a source of clean carbon-neutral energy.

Although a great deal has been learnt through a combination of theoretical models and observation of the universe right across the electromagnetic spectrum including visible light with conventional optical telescopes, many questions on energetic processes taking place billions of miles away still remain unanswered.This is why astrophysicists are turning to a third ingredient, the high energy laboratory, fusing results obtained there with theoretical models and direct observation through instruments. The state of this highly promising field was discussed at a recent workshop organised by the European Science Foundation (ESF), which also set out a roadmap for future collaborative research in Europe over the next five years.

The workshop is setting up a European framework for conducting coordinated experiments in Extreme Laboratory Astrophysics (ELA), aiming to simulate the high temperatures and magnetic fields experienced in a variety of formative processes occurring throughout the universe's history. Full blown ELA builds on earlier more tentative initiatives, such as the JETSET network, which is a four-year Marie Curie Research Training Network (RTN) funded by the European Commission, designed to build a vibrant interdisciplinary European Research and Training community centred on rigorous and novel approaches to plasma jet studies, with a focus on flows produced during star formation. Plasma jets comprise high energy atomic nuclei stripped of their electrons, expelled from stars during their formation and early in their lives.

ELA experiments however, as discussed at the ESF workshop, go much further than the study of plasma jets, and therefore expand on the foundations created by JETSET. "The JETSET network was truly innovative in that it combined not only theoretical and observational astrophysics, but also for the first time experiments," said Andrea Ciardi, convenor of the ESF workshop and plasma physicist at the Ecole Normale Superieure in Paris. "However JETSET was limited in terms of astrophysical phenomena studied (jets from young stars) and in terms of groups involved. The workshop aims at the creation of an XLA framework combining numerical modelling, experiments and theory, to complement observations in the study of a broader range of astrophysical phenomena."

The workshop fulfilled its objectives of stimulating the required interdisciplinary research effort, and providing a broad outlook of future objectives. Furthermore it generated great excitement about prospects for the field, according to Ciardi. "The workshop covered a large spectrum of research both in astrophysics and in laboratory plasma physics: from cosmic rays acceleration, to the properties of fast winds in stars, and from high-power lasers aimed at achieving fusion to experiments producing magnetic bubbles expanding at hundreds of kilometres per second," said Ciardi. "Indeed the excitement comes from being able to re-create in the laboratory astrophysical phenomena taking place in some of the most extreme and exotic objects in the universe."

The ELA experiments should also have practical benefits. "ELA research has an inherent duality: experiments developed initially for laboratory astrophysics, including new diagnostics, theoretical and numerical models, can be useful for example to fusion research, which is pursuing a clean source of energy, which in some cases uses similar theoretical and experimental techniques," said Ciardi.

ELA research could also help improve weather forecasts by leading to better understanding of cosmic rays that strike the earth's atmosphere and have a significant effect on cloud formation and thunderstorm activity.

The ESF workshop, Extreme Laboratory Astrophysics: Advances and Opportunities in High-Energy Density Experiments, was held in Paris (France), in September 2008.

Adapted from materials provided by European Science Foundation.
ScienceDaily

Dwarf Crocodiles Split Into Three Species

2008-12-25T21:37:00.000+06:00

O. tetraspis eats a captures a land crab at Loango National Park, Gabon. (Credit: Mitchell J. Eaton)

You'd think that if scientists were to discover a new species, it would be in some remote, uncharted tropical forest, not a laboratory in New York. But a team from the Sackler Institute for Comparative Genomics at the American Museum of Natural History has done the unexpected. Looking at the genes of the African dwarf crocodile, researchers found that the group — genetically speaking — comprises three distinct species rather than one.

This not only ends a long debate about the taxonomy of this group, previously thought to consist of two closely related subspecies, but also defines a new, distinct species from genetic samples.

"In the past, the two morphologically distinct crocodile populations were believed to be different genera, then later different species, and then finally different subspecies," explains first-author Mitchell Eaton. Eaton conducted the research at the Sackler Institute and is finishing his doctoral degree at the University of Colorado. "We collected samples in Africa to explore this taxonomic question, and we found a great deal of evolutionary divergence between populations in the Congo Basin and on the west coast of Central Africa. We also — quite unexpectedly — found a completely new species from far West Africa; there may be even more species that we haven't sampled yet!"

African dwarf crocodiles, genus Osteolaemus, live in the tropical forests of Central and West Africa. Adults typically grow to no more than 5 feet in length and are the smallest living members of the crocodilian family. The three groups identified in this current research include a species from the Congo Basin (O. osborni), another from Central Africa's Ogooué Basin (O. tetraspis), and the new, yet unnamed species from West Africa. All of these crocodiles look very similar, and all are widely hunted by local people as a source of food. In fact, these animals provide up to a quarter of the non-fish bush meat consumed in some areas of Central Africa, but over-hunting to supply commercial 'bushmeat' markets may threaten many populations with extinction. Dwarf crocodiles are listed as vulnerable on the International Union for Conservation of Nature's Red List.

In the laboratory, the researchers sequenced more than 4,000 base pairs of both mitochondrial and nuclear DNA from as many as 82 individuals sampled across Central and West Africa. The results confirmed species-level separations between three different groups of dwarf crocodiles. Crocodiles from the Congo Basin appear to be the oldest of the three species, with some morphological characteristics placing them closer to a shared ancestor of the Nile crocodile. The dwarf crocodiles of the Ogooué and West Africa, on the other hand, are more recently evolved and are more closely related to each other than either is to the Congo Basin species.

"These species have been on their own evolutionary trajectory for a long time," says George Amato, Director of the Sackler Institute. "They are diagnostically distinct — every individual in one species has characteristics that are not found in the other species, and the number of diagnostic characteristics is large."

The new taxonomic discovery has implications for the conservation strategy of African dwarf crocodiles. "Without these genetic results, the level of biodiversity was cryptic, hidden," Amato continues. "Accurate taxonomy is necessary for conservation management of each species, and now we can calculate subsistence hunting levels that are manageable."

In addition to Amato and Eaton, coauthors include Andrew Martin of the University of Colorado and John Thorbjarnarson of the Wildlife Conservation Society (WCS). The research was funded in part by AMNH, the National Geographic Society, WCS, Lincoln Park Zoo, the Rufford Foundation, and the University of Colorado's Natural History Museum and Rozella Smith Fellowship. It is published in the early online edition of Molecular Phylogenetics and Evolution.

Adapted from materials provided by American Museum of Natural History, via EurekAlert!, a service of AAAS.
ScienceDaily

Immunity Stronger At Night Than During Day

2008-12-25T21:36:00.000+06:00

A fruit fly's immune system can tell time, researchers at the Stanford University School of Medicine have found, and how hard it punches back against infections depends on whether the fly is snoozing or cruising. The discovery could have implications for human health, too.

Working with jerry-rigged, light-bulb-laden shoeboxes to manipulate the flies' daily cycle and with syringes small enough to inject measured amounts of germs into the wee winged ones, the investigators have shown that the insects' immune response waxes and wanes with the diurnal oscillations called circadian rhythms.

Mimi Shirasu-Hiza, PhD, a postdoctoral scholar in the laboratory of David Schneider, PhD, assistant professor of microbiology and immunology, presented the findings Dec. 14 at the annual meeting of the American Society for Cell Biology, held in San Francisco.*

Insects do not have the advanced artillery that characterizes vertebrate immune systems — antibody-secreting B-cells, and killer and helper T-cells that precisely target specific pathogens for attack. But they do share with vertebrate organisms a primitive, but critical, rough-and-ready response to unwanted microbes: the innate immune system. This all-important first line of defense, without which we wouldn't survive an infection for the week or two it takes for our more-sophisticated antibodies and T-cells to kick into high gear, whirls into action at once, based on its ability to recognize generic patterns that distinguish microbial pests.

One feature of the fruit fly's innate immune system is the presence of circulatory cells called phagocytes that, like our own white blood cells, engulf and digest bacteria. In their new research, Shirasu-Hiza and Schneider have found that phagocytes' activity oscillates throughout the day.

Like the mosquito, platypus and whitetail deer, fruit flies are crepuscular — they are most active at dawn and dusk, tend to roam a bit during the daytime, and engage in what passes for sleep during the nighttime. (Flies don't have eyelids, so it's hard to tell if they're really asleep. Researchers instead characterize cyclical patterns of rest and activity in terms of the number of movements per five-minute cycle.)

Shirasu-Hiza flummoxed flies into a 12-hour circadian-rhythm phase shift by raising them in shoeboxes, wired by Schneider with timers that controlled batteries of light bulbs. This enabled the researchers to infect two sets of flies (from "nighttime" or "daytime" shoeboxes) in a single experimental session. This Shirasu-Hiza did, using syringes fashioned from glass capillary tubes heated and then stretched so that they were extremely thin, but still hollow. Armed with these syringes — which are powered by a machine called a "Picospritzer" — she spent hours on end in a dark room lit only by a red bulb (red light doesn't seem to perturb the daily rhythms of the flies) while injecting, one by one, multiple hundreds of tiny, week-old male flies (half of them sleeping, the other half awake) per session with precise volumes of solutions containing different pathogenic bacteria.

In previously published research, when Shirasu-Hiza and her colleagues had infected normal flies with measured doses of two noted human pathogens, Streptococcus pneumoniae or Listeria monocytogenes, the sickened flies' circadian rhythms were disturbed. They stumbled around more randomly, and stood still for relatively shorter periods. Moreover, genetic mutants lacking circadian cycles of rest and activity died more quickly on infection with these pathogens than normal flies did.

In the new round of experiments, the researchers observed that, consistent with those earlier findings, the activity of phagocytes in normal fruit flies oscillates with their circadian rhythms. Flies infected with S. pneumonia or L. monocytogenes during resting periods ("nighttime") also survive significantly longer than those infected during active periods ("daytime"). Further, by injecting fluorescently labeled dead bacteria into flies at different points in their circadian cycle, the investigators could see increased phagocyte function at night for those two pathogens: there was an increase in the number of bacteria ingested by phagocytes in flies infected during resting versus active phases. Likewise, circadian-mutant flies "trapped" in the active phase had decreased phagocyte function, demonstrating that phagocyte activity is subject to regulation by circadian proteins whose activity, in turn, is disrupted by these mutations.

Strangely, though, infecting the flies with a third bacterial pathogen, Burkholderia cepacia, produced the opposite result. Circadian-mutant flies coped better with the infection than did normal flies, suggesting that in this case, a disrupted circadian rhythm might actually be good for the flies.

That poses an intellectual challenge, Schneider said: "If a sick fruit fly were to walk into my office, and it were infected with Burkholderia, I would know that I should deprive it of sleep. But I don't know the rules for people. In hospitals, nurses and orderlies are going in and out all the time, and you never get any sleep. Is that good, or bad? There are probably conditions where that's going to make things much worse. But maybe there are some conditions where it's actually better for you to have your sleep continuously interrupted. We're trying to figure out the rules for the fly, and hopefully someone else can translate it into human biology: Do they put you in a quiet room, or do they keep coming in and fiddling with your IV on purpose?"

*The paper, "Circadian rhythm and immunity in Drosophila: a model for neuroimmune communication," was presented on Dec. 14, at the Moscone Center.

The work was funded by the National Institutes of Health.

Adapted from materials provided by Stanford University Medical Center, via EurekAlert!, a service of AAAS.
ScienceDaily

Predecessor of Cows, The Aurochs, Were Still Living In The Netherlands Around AD 600

2008-12-25T21:34:00.001+06:00

Archaeological researchers at the University of Groningen have discovered that the aurochs, the predecessor of our present-day cow, lived in the Netherlands for longer than originally assumed. Remains of bones recently retrieved from a horn core found in Holwerd (Friesland, Netherlands), show that the aurochs became extinct in around AD 600 and not in the fourth century.

The last aurochs died in Poland in 1627. In January 2008, the bony core horn was unearthed in a mound near Holwerd by amateur-archaeologist Lourens Olivier from Ternaard. The Groningen Institute for Archaeology at the University of Groningen has established that it came from the left horn of an aurochs bull, and C14 dating reveals that the horn dates back to between AD 555 and 650.

The horn core is the bony core of the horn of a bovine animal. While the aurochs was still alive, the horn core would have been covered by a sheath of horn. This horn sheath has since decomposed in the soil. The largest curve in the horn core found in Holwerd measures 59 cm. The whole horn, including the horn sheath, must have been at least 70 cm long.

The aurochs was much larger than the common cows we know today, with aurochs bulls measuring between 160 and 180 cm at the withers, and aurochs cows between 140 and 150 cm. The cattle bred on the Frisian mounds around AD 600 measured between 90 and 120 cm and their horn cores were 25 cm long at the most.

Hunters and the first Dutch farmers hunted the aurochs. The species eventually became extinct in the Netherlands, not only because it was hunted, but also because more and more land was being used for agriculture and the human population was increasing.

Aurochs bones dating back to Roman times have previously been found at various sites in the Dutch river regions. They have also been unearthed in the terps and mounds of Friesland and Groningen. An almost complete skeleton of an aurochs was found in a terp in Britsum (Friesland), 15 km from Holwerd. It dates back to between AD 257 and 421. It was long thought that this was the most recent evidence of the aurochs that would be found, and that the aurochs had therefore become extinct in the Netherlands sometime in the fourth century AD. However, the horn core from Holwerd shows that the aurochs must have been grazing the Frisian meadows for at least another 150 to 250 years.

The find is reported in the newsletter ‘Van Warden en Terpen’ (From Mounds and Terps), published on 4 December 2008 by the Terp Research Association.

Adapted from materials provided by University of Groningen.
ScienceDaily

Robotic Aircraft Designed For Weather Forecasting

2008-12-25T21:32:00.001+06:00

Improving weather forecasting could also save lives. The more time to prepare for a storm and evacuate the area, the better. Currently, forecasts made more than 48 hours in the future aren't considered highly reliable. (Credit: iStockphoto/Mike Bentley)

At MIT, planning for bad weather involves far more than remembering an umbrella. Researchers in the Department of Aeronautics and Astronautics are trying to improve weather forecasting using robotic aircraft and advanced flight plans that consider millions of variables.

"Weather affects huge sectors of our economy, such as agriculture and transportation," said Nicholas Roy, an assistant professor and one of the researchers who worked on the project. With more time for advanced planning, farmers could bring in their crop before a big storm hits. Airlines could adjust their flight schedules further in advance, reducing the impact on customers.

Improving weather forecasting could also save lives. "People do get killed in these storms," said Aero-Astro Professor Jonathan How, the principal investigator. The more time to prepare for a storm and evacuate the area, the better. Currently, forecasts made more than 48 hours in the future aren't considered highly reliable.

The researchers hope to gain some lead-time by improving the way data about current weather conditions are collected. Existing forecasting systems depend on pressure, temperature, and other sensors aboard a single piloted airplane that flies scripted routes. But the data that are collected can't be processed fast enough to alter the flight plan if a storm starts brewing. "The response time is fairly slow," How said. "Today's flight path is based on yesterday's weather."

Ideally, teams of unmanned aircraft would be used to gather data. Current sensor readings from one plane would be used to guide the deployment of additional planes to areas with especially interesting or changing weather. By gathering information from several key areas at the same time, the researchers believe they could offer more accurate forecasts.

"We'd like to better predict the weather three to five days in advance," said Han-Lim Choi, a postdoctoral associate in How's lab.

But this is no easy task, largely because weather involves extremely complicated interactions between a lot of different factors. And while the researchers focused their work on the area over the Pacific Ocean, this was still a vast expanse to consider in terms of automated flight planning. Traditional robotic planning algorithms don't scale well to problems of that size, How explained. So the key challenge was creating an algorithm that could develop an effective flight plan quickly, based on millions of variables.

After three years of research using computerized weather simulations, the team believes their algorithm can quickly and efficiently determine where aircraft should be sent to take the most important measurements. Essentially, the algorithm works by determining the relative utility of taking different flight paths to gather measurements. How said their system can create a new flight plan within six hours of collecting data.

Choi, who recently earned an MIT PhD for his work on the project, will describe the research at this month's IEEE Conference on Decision and Control.

How said the results of the research could reach far beyond weather prediction. Intelligent path planning is essential for all kinds of mobile robots, be they autonomous cars or mail-carrying robots. The research also be used, How noted, to help environmental engineers determine where best to take samples to determine the source of a contaminant.

Although the system has not yet been used with real aircraft, How's team continues to test their algorithm against increasingly complex weather models with the help of former MIT meteorologist James Hansen, who is now with the Naval Research Laboratory.

The research was funded by the National Science Foundation.

Adapted from materials provided by Massachusetts Institute of Technology.
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