Friday, December 18, 2009


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A novel geolocation system makes use of signals from Galileo, the future European satellite navigation system, to locate avalanche victims carrying an avalanche transceiver or a cellphone, to the precision of a few centimeters.

For many skiers and snowboarders, there is nothing quite like being the first to make tracks in the virgin snow, off the regular piste. But this can be a fateful decision, because the risk of avalanche is many times greater here. Once buried under a mass of snow, a person’s only hope of survival is if their location can be pinpointed swiftly. If not rescued within half an hour, their chances of being found alive diminish rapidly. Victims stand the best chance of being saved if the uninjured members of their group start searching for them immediately – but for that the buried victim needs to be wearing an avalanche beacon.

“In the experience of rescue teams not everyone actually carry beacons,” says Wolfgang Inninger of the Fraunhofer Institute for Material Flow and Logistics IML. “However, nearly everyone has a cellphone. This is why we decided to enhance our automatic geolocation system that works with Galileo, the future European satellite navigation system.” To do so, two new components have been added to the ‘avalanche rescue navigator’ ARN: a cellphone location function and software that calculates the position of the buried victim on the basis of local measurements. Starting from the approximate place where the victim is thought to be lying under the snow, the rescuers measure the field strength of the signal transmitted by the cellphone or beacon at three to five reference points. The system then uses a highly precise calculation algorithm to pinpoint the source of the signal, indicating with high probability the location of the buried victim. In this kind of situation, the position relative to the rescue team’s starting point is more important than the absolute position relative to global coordinates, which may be subject to measurement inaccuracies. This gives the rescuers immediate information on the direction and distance from their present location at which the victim can be found.

For their development work on the system, the researchers are using the GATE Galileo test and development environment in Berchtesgaden, where transmitter antennas installed on six mountain peaks simulate the Galileo signals. The researchers intend to combine these signals – and the real ones, after 2012 – with signals from existing satellite navigation systems such as the American GPS and the Russian Glonass, and to add signals for error estimation and correction. The project is being implemented by a consortium of regional companies, institutes and universities in collaboration with the Berchtesgaden mountain rescue service and the police, and is being sponsored by the German Aerospace Center DLR.

Fraunhofer Institute


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The bodywork on motor vehicles must be sufficiently stable, but processing the high-strength steels involved – for example punching holes in them – can prove something of a challenge. A new steel-cutting process will save time, energy and money in the future.

Squealing tires and the crunch of impact – when an accident occurs, the steel sheets that form a motor vehicle’s bodywork must provide adequate impact protection and shield its passengers to the greatest extent possible. But the strength of the steels that are used throw up their own challenges, for example when automobile manufacturers have to punch holes in them for cable routing. Struggling to pierce the hard steel, mechanical cutting tools rapidly wear out. And because they also leave some unwanted material on the underside of the steel (burr, as the experts call it), additional time has to be spent on a finishing process. One possible alternative is to use lasers as cutters, but they require a great deal of energy, which makes the entire process time-consuming and costly.

Working together with a number of partners including Volkswagen, researchers at the Fraunhofer Institute for Machine Tools and Forming Technology IWU in Chemnitz have come up with another way to make holes in press-hardened steel bodywork. Dr. Verena Kräusel, head of department at the IWU, explains: “The new method is based on electromagnetic pulse technology (EMPT), which was previously used primarily to expand or neck aluminum tubes. We’ve modified it to cut even hard steels. Whereas a laser takes around 1.4 seconds to cut a hole, EMPT can do the job in approximately 200 milliseconds – our method is up to seven times faster.” Another advantage is that it produces no burr, thus doing away with the need for a finishing process. Stamping presses become superfluous, and no costs arise from the need to replace worn-out parts.

The pulse generators comprise a coil, a capacitor battery, a charging device and high-current switches. When the switch closes, the capacitors discharge via the coil within a matter of microseconds, producing a high pulsed current. The coil converts the energy stored in the capacitors into magnetic energy. To be able to use this process to cut steel, the researchers simply had to modify the coil to ensure the resulting electromagnetic field is strong enough: the pressure with which the field hits the steel must be so high that it forcibly expels the material from the sheet. “The impact pressure on the steel is approximately 3,500 bar, which equates to the weight of three small cars on a single fingernail,” says Kräusel. PSTproducts GmbH in Alzenau provided the original EMPT system. With regard to the customer demands the researchers develop now the coils for various cutting geometries.

Fraunhofer Institute


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New scientific evidence refutes the preconception that testosterone causes aggressive, egocentric, and risky behavior. A study at the Universities of Zurich and Royal Holloway London with more than 120 experimental subjects has shown that the sexual hormone with the poor reputation can encourage fair behaviors if this serves to ensure one's own status.

Popular scientific literature, art, and the media have been attributing the roll of aggression to the arguably best known sexual hormone for decades. Research appeared to confirm this – the castration of male rodents evidently led to a reduction in combativeness among the animals. The prejudice thus grew over decades that testosterone causes aggressive, risky, and egocentric behavior. The inference from these experiments with animals that testosterone produces the same effects in humans has proven to be false, however, as a combined study by neuroscientist Christoph Eisenegger and economist Ernst Fehr, both of the University of Zurich, and economist Michael Naef of Royal Holloway in London demonstrates. "We wanted to verify how the hormone affects social behavior," Dr. Christoph Eisenegger explains, adding, "we were interested in the question: what is truth, and what is myth?"

For the study, published in the renowned journal Nature, some 120 test subjects took part in a behavioral experiment where the distribution of a real amount of money was decided. The rules allowed both fair and unfair offers. The negotiating partner could subsequently accept or decline the offer. The fairer the offer, the less probable a refusal by the negotiating partner. If no agreement was reached, neither party earned anything.

Before the game the test subjects were administered either a dose of 0.5 mg testosterone or a corresponding placebo. "If one were to believe the common opinion, we would expect subjects who received testosterone to adopt aggressive, egocentric, and risky strategies – regardless of the possibly negative consequences on the negotiation process," Eisenegger elucidates.

The study's results, however, contradict this view sharply. Test subjects with an artificially enhanced testosterone level generally made better, fairer offers than those who received placebos, thus reducing the risk of a rejection of their offer to a minimum. "The preconception that testosterone only causes aggressive or egoistic behavior in humans is thus clearly refuted," sums up Eisenegger. Instead, the findings suggest that the hormone increases the sensitivity for status. For animal species with relatively simple social systems, an increased awareness for status may express itself in aggressiveness. "In the socially complex human environment, pro-social behavior secures status, and not aggression," surmises study co-author Michael Naef from Royal Holloway London. "The interplay between testosterone and the socially differentiated environment of humans, and not testosterone itself, probably causes fair or aggressive behavior".

Moreover the study shows that the popular wisdom that the hormone causes aggression is apparently deeply entrenched: those test subjects who believed they had received the testosterone compound and not the placebo stood out with their conspicuously unfair offers. It is possible that these persons exploited the popular wisdom to legitimate their unfair actions. Economist Michael Naef states: "It appears that it is not testosterone itself that induces aggressiveness, but rather the myth surrounding the hormone. In a society where qualities and manners of behavior are increasingly traced to biological causes and thereby partly legitimated, this should make us sit up and take notice." The study clearly demonstrates the influence of both social as well as biological factors on human behavior.

University of Zurich


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A team led by scientists at The Scripps Research Institute have discovered a direct link between insulin—a hormone long associated with metabolism and metabolic disorders such as diabetes—and core body temperature. While much research has been conducted on insulin since its discovery in the 1920s, this is the first time the hormone has been connected to the fundamental process of temperature regulation.

The paper was published recently in an advance, online issue of the journal Diabetes, a journal of the American Diabetes Association, and will appear in the January print edition of the publication.

The scientists found that when insulin was injected directly into a specific area of the brain in rodents, core body temperature rose, metabolism increased, and brown adipose (fat) tissue was activated to release heat. The research team also found that these effects were dose-dependent—up to a point, the more insulin, the more these metabolic measures rose.

"Scientists have known for many years that insulin is involved in glucose regulation in tissues outside the brain," said Scripps Research neurobiologist Manuel Sanchez-Alavez, who was first author of the new paper with Bartfai lab colleagues Iustin V. Tabarean and Olivia Osborn (now at the University of California, San Diego). "The connection to temperature regulation in the brain is new."

In addition to suggesting a fresh perspective on diseases such as diabetes that involve the disruption of insulin pathways, the study adds to our understanding of core body temperature—the temperature of those parts of the body containing vital organs, namely the trunk and the head. Normally, core body temperature stays within a narrow range so that key enzymatic reactions can occur. When core body temperature goes outside this range for prolonged periods—higher as in fever, or lower as in hypothermia—the result is harm to the body.

More modest variations in core body temperature are associated with our daily 24-hour sleep-wake cycle, the female monthly hormonal cycle, and, intriguingly, the effects of severe calorie restriction.

"Our paper highlights the possibility that differences in core temperature may play a role in obesity and may represent a therapeutic area in future drug design," added Osborn.

The laboratory of Tamas Bartfai, who is chair of the Department of Molecular and Integrative Neurosciences, director of the Harold Dorris Neurological Research Institute, and a member of The Skaggs Institute of Chemical Biology at Scripps Research, has been investigating the biology of temperature regulation for almost a decade. The idea for the new study came about from some recent experiments in his lab exploring the properties of cells called "warm-sensitive neurons." These cells exist only in the preoptic area of the brain, which is known to regulate core body temperature.

In work coordinated by Osborn to characterize these neurons and their transcriptome (all of the messenger RNA molecules in a cell, which reflect the genes being expressed), the team noticed something unexpected—a messenger RNA for an insulin receptor.

"We were surprised to find the insulin receptor," said Tabarean. "The insulin receptor is very well documented in the pancreas and in other peripheral tissues. But in the brain, it was not clear and we definitely did not know about its existence in warm-sensitive neurons."

Hypothesizing that insulin was acting in the regulation of core body temperature because of its presence in warm-sensitive neurons, the scientists set out to investigate. To do so, they used a rare combination of techniques including molecular biology at the single-cell level, electrophysiology, imaging techniques, and in vivo metabolic studies.

First, Tabarean led the single-cell work, examining the effect of insulin on individual warm-sensitive neurons, which fire more frequently when temperature rises. Results showed that insulin was potent in reducing the neurons' firing rate.

Next, members of the Bartfai lab designed several whole animal studies to confirm these findings and examine the pathways in the body that might be affected.

The scientists suspected that insulin in the brain might work to warm the body through a specific pathway involving signals that traveled from the brain's preoptic area, down the spinal cord, to neurons that direct brown adipose tissue to expend energy to produce heat.

Brown adipose tissue, also known as brown fat, is distinct from white fat in that it burns calories rather than storing them. While in years past, brown fat was thought to exist in humans only when they are infants, recent studies have shown that brown fat deposits are also found in healthy adults, especially around their collarbones and necks. Interestingly, older people have less brown fat than younger people, and obese individuals have less than lean individuals.

To see if brown fat was activated by insulin in the brain, the Bartfai group collaborated with members of Seimens Medical Solutions, who are experts in imaging techniques. Specifically, the scientists examined the effect of insulin injections in the preoptic area of rats on brown adipose tissue using Computerized tomography (CT) scans and positron emission tomography (PET) scans. Rodents possess brown adipose tissue in two large masses on their backs between the shoulder blades.

When the activity of the brown fat was captured visually, the data confirmed the scientists' projections.

"After insulin injection into the preoptic area, the brown adipose tissue lights up very beautifully," said Sanchez-Alavez.

Next, Sanchez-Alavez led studies examining the effects of insulin on metabolism, specifically by measuring the effect of insulin injections in the preoptic area of mice on oxygen consumption and carbon dioxide production. Again, results showed that metabolic rate increased with an increase in insulin.

"All the techniques—PET/CT scan, metabolic studies, telemetric work—support the hyperthermic effect of insulin in rodent models," Sanchez-Alavez summarized.

The authors note that while their new paper illuminates a key piece of the puzzle of the body's metabolic processes, it also raises many intriguing questions: How does insulin get to the brain's preoptic area—does it cross the blood-brain barrier or is it produced locally? Are diabetics, who are insensitive to insulin in peripheral tissues, still sensitive to insulin in the brain; if so, could this dichotomy be used in the development of a new therapy? Could scientists find a way to use these new insights to increase energy expenditure for the purpose of weight loss?

"This is a very long project," said Sanchez-Alavez. "I hope we get funding to continue this research."

The Scripps Research Institute


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What happens when soldiers in hostile areas capture valuable documents written in a language they don’t speak and in a non-Roman script they can’t read? Are the documents exploited for their intelligence value, or are they stored unread and unevaluated?

All too often, it is the latter—a case of too many documents and too few translators.

American soldiers captured more than 2 million documents during the first few years of U.S. military involvement in Iraq and Afghanistan. Of these, fewer than 3 percent have been evaluated, mostly by human eyes with little help from computers.

Henry Baird and Daniel Lopresti, professors of computer science and engineering, have resolved to change that. Early in the U.S. anti-terrorism campaign they concluded that new research was needed to develop high-performance document analysis techniques to help military intelligence officials. They recommended that DARPA (the Defense Advanced Research Projects Agency) launch a program to support the development of a faster, more computerized capability to understand and translate documents.

The result of these efforts was DARPA funding for the MADCAT (Multilingual Automatic Document Classification, Analysis and Translation) project, in which Baird and Lopresti are participating. Its purpose is to use computers to convert foreign-language text images into English transcripts. Its early focus was on Arabic documents and it has made impressive progress in recognizing Arabic handwriting.

Building on these successes, the Lehigh team made the case for a second, more far-reaching undertaking, the Document Analysis and Exploitation (DAE) project. This proposal was shepherded through the government approval process by Bill Michalerya, associate vice president for government relations and economic development at Lehigh, and was recently approved by Congress. Together, MADCAT and DAE represent the largest investment of federal research grants in document image analysis in two decades.

In the new project, Baird and Lopresti and Hank Korth, also a professor of computer science and engineering, are leading efforts to advance the automation of document analysis and to provide a national resource to enable shared research and access. The three faculty members and their students are collaborating with BBN Technologies of Massachusetts.

Baird brings to the project more than 20 years of experience in computer vision and pattern recognition. He has authored and edited prominent books on the subject and published numerous articles. Lopresti, the co-director of Lehigh’s Pattern Recognition Research Lab, has published widely in the areas of document analysis, handwriting, computer security and bioinformatics. Korth, an expert in databases, has published more than 100 technical publications, including the widely-used text Database System Concepts, which is now in its sixth edition.

Applications as diverse as digital libraries, medical records, and the discovery process for lawsuits will benefit from automated document analysis, say the three researchers. But the immediate need—national security—adds urgency to the effort.

The goal of the DAE project goes well beyond the computerized “reading” that’s been around for decades.

Simple document scanning, long used in copiers and fax machines, produces a photo-like representation of a document, not a file that people can search and edit. OCR (optical character recognition) software can understand some machine-printed text and so allow for searching and editing. But it’s limited mostly to Western languages on very clean documents.

“You can buy decent OCR machines these days for printed text, but not for handwriting,” Baird says. “But if you look for Arabic, Ethiopian languages and many other non-Western languages, for example, you won’t find usable technology.”

In addition, says Baird, OCR is not able to recognize unusual fonts, poor-quality faxes, bleed-throughs, or even yellowing paper in old books.

And those challenges don’t even begin to cover the demanding needs of the military intelligence community.

“People in the field might get a pile of papers in handwritten Arabic scribbles,” Baird says. “In addition to text, the documents can contain maps, tables of information, drawings and photographs. We’d like to automate the analysis of these as well.”

“We also want go beyond the actual written text to meta-data,” Lopresti says. “For example, if we can tell that documents appear to be written by the same author, that’s incredibly valuable information.”

Automating document analysis involves three steps: scanning the document; converting images to computer-readable characters; and translating and evaluating the content.

“There’s been much agreement over the past 20 years on how to describe ordinary language text for computers,” Baird says, “but not on mathematics, chemical diagrams, maps, or tabular data. That’s what this project is all about. We’re developing the technology to automate people’s ability to read and understand the contents of all kinds of documents. And that turns out to be pretty hard.”

To do that they will exploit synergies of document layout analysis, character recognition, language modeling and parsing, link analysis, and semantic modeling. The result will be script- and language-independent, making it easily transferable to new applications.

“This project has two main thrusts,” says Lopresti. “One is to develop new techniques for extracting information from documents. The other is to make available to the research community these techniques plus data sets for producing new algorithms and techniques.”

“The database challenges,” Korth states, “relate to the type of information that must be stored and the ways in which we anticipate the data being used. For example, we’ve had to consider collaborative document analysis. What are the problems when lots of teams analyze lots of documents using lots of different tools? We need to design a database that can store the information efficiently so that it can be shared by all the potential users.”

The DAE project, says Lopresti, represents “a small slice of the research trajectory.” The Lehigh team is already looking ahead to the next challenge.

“Right now the emphasis is on Arabic,” Baird states. “Six or 12 months from now, though, who knows where the interest will be? We want to have techniques that are robust, well-developed, debugged, proven and ready to go, so that we can quickly adapt to any situation of interest.”

Lehigh University


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Toddlers are distractible. Their minds flit constantly here and there, and they have a terrible time concentrating on even the most stimulating project. They might be fascinated by a colorful new toy, but only until the next best toy comes along. This can be maddening for parents or teachers, who often try to rein in a toddler’s impulsivity.

But should we really be trying to teach self-control? Psychologists are beginning to raise these questions, and some are even suggesting that it may be detrimental to the developing brain to push it toward maturity too soon. University of Pennsylvania neuropsychologist Sharon Thompson-Schill and her colleagues study a region of the brain called the prefrontal cortex, or PFC, the part of the brain that filters out irrelevant information and allows us to focus. It is also the last part of the brain to mature and become fully functional. It lags behind the rest of the brain until about age four.

In the most recent issue of Current Directions in Psychological Science, a journal of the Association for Psychological Science, Thompson-Schill and colleagues speculate that an immature PFC may not be a deficit at all, but rather an advantage in the first years of life. Here’s an example: It has to do with guessing. Say you are naïve about the game of football, but you are playing a guessing game: Will the offensive team pass or run the ball? You observe that the team passes the ball three out of every four plays, so you guess “pass” 75 percent of the time and “run” 25 percent of the time.

That’s not smart. Smart would be saying “pass” all the time. And if you played this game with your toddler, that is likely what he or she would do. Toddlers are often better at this, because their immature brains are still operating on a brute-force competition between two alternatives: pass or run. They are not yet capable of guessing.

For toddlers, this inability is a good thing, because they can’t afford to guess. They have a lot of learning to do, and much of that learning has to do with hard-and-fast rules and conventions. In fact, this rigidity may be essential to language acquisition. Learning language is an intimidating task; it requires saying the right thing in the right context, and agreeing with everyone else that these are the right things to say. It’s no surprise, the psychologists note, that kids pick up languages so effortlessly compared to adults.

And it’s not just language. Toddlers are mastering all sorts of social conventions that simply must be learned. They’re the rules of the world. In this sense, trying to hasten the brain’s development may be not only difficult by unwise.

Association for Psychological Science


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How do fruit flies get high cholesterol and become obese? The same way as people do - by eating a diet that's too rich in fats.

More importantly, according to two new studies led by a University of Utah human geneticist, fruit flies use the same molecular mechanisms as humans to help maintain proper balances of cholesterol and a key form of stored fat that contributes to obesity. The findings mean that as researchers try to learn more about the genetic and biological processes through which people regulate cholesterol and fat metabolism, the humble fruit fly, also called Drosophila, can teach humans much about themselves.

"Not a lot is known about these regulatory mechanisms in people," says Carl S. Thummel, Ph.D., professor of human genetics at the U of U School of Medicine and senior author on the two studies. "But we can learn a lot by studying metabolic control in fruit flies and apply what we learn to humans."

High cholesterol and obesity, which affects an estimated 25 percent to 30 percent of the U.S. population, are linked to heart disease, diabetes, and other diseases that take huge tolls on health and add billions of dollars to the nation's medical bills. Understanding the processes that regulate cholesterol and fat in humans could be critical for addressing those health risks in people, Thummel believes.

The two studies identify a nuclear receptor, DHR96, which plays a critical role in regulating the balance or homeostasis of cholesterol and another fat molecule called triacylglycerol (TAG). Nuclear receptors are proteins that sense the presence of chemical compounds within cells. DHR96 corresponds closely to a nuclear receptor in humans, called LXR, that is known to regulate cholesterol levels.

In a study published Dec. 2 in Genes and Development, Thummel and colleagues at the U of U and two Canadian universities show that DHR96 helps regulate cholesterol in fruit flies by binding with this compound. When this binding occurs, it allows DNA to be read, which switches genes on and off that help maintain proper levels of cholesterol, according to Thummel, who also holds an H.A. and Edna Benning Presidential Endowed Chair in Human Genetics.

The researchers used a technique developed by University of Utah biologist Kent Golic, Ph.D., in which they silenced or disabled the DHR96 protein so it couldn't function in fruit flies. They then grew flies in which DHR96 was silenced. Depending on what the fruit flies were fed, lean or fat diets, they had either too little or too much cholesterol. Flies fed too little cholesterol died, while those with too much developed hypercholesterolemia or chronically excessive cholesterol levels. At the same time, flies in which DHR96 functioned normally maintained a proper level of cholesterol.

"When they lacked the DHR96 receptor, the flies were unable to maintain cholesterol homeostasis," Thummel says. "This is similar to what happens in humans who have high cholesterol levels."

Fruit flies are good for such research insights in large part because of the insects' short life span - about 30 days - meaning their development and biological processes are more easily observed than in other, longer-lived models, such as mice. Fruit flies also are easy to manipulate genetically and are less expensive to study compared to mice or other models, according to Thummel. In addition, the mechanisms by which metabolism is controlled in fruit flies are very similar to those in mice or humans.

"We can do a lot more mechanistic studies in a fly than are possible in a mouse," he says. "We can study metabolic pathways faster and more in-depth."

Along with its important role in helping to maintain proper levels of cholesterol, DHR96 also plays an integral part in regulating dietary fat metabolism, Thummel and another U of U researcher report in a Dec. 2 study in Cell Metabolism.

In flies in which DHR96 was silenced, TAG levels were markedly reduced in the intestine, making the insects resistant to diet-induced obesity. But when DHR96 was overexpressed, meaning there were higher levels of the protein, it led to increased TAG levels and made the flies more prone to being overweight. These findings show that DHR96 is required for breaking down dietary fat in the intestine of fruit flies and provide insight into how dietary fat metabolism is regulated in Drosophila.

"This nuclear receptor plays a major role in sensing and regulating cholesterol and TAG uptake in the intestine in fruit flies," Thummel says. "It functions similarly to the way LXR functions in humans, although we have a relatively poor understanding about how LXR controls these pathways."

In his future studies, Thummel intends to learn more about how DHR96 regulates metabolism by studying the functions of the genes that it controls.

University of Utah


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Using the latest technology, researchers are uncovering evidence of exactly how major a role activity plays in the battle to keep obesity at bay. In new report published in the British Medical Journal, scientists have shown that it’s the type of exercise you do, rather than the amount, that’s most important.

Building on previous work in this field from the same team, the research provides evidence that being active in childhood protects against later obesity.

The work, which uses information from the Bristol-based Children of the 90s study, suggests that making even small increases to your daily exercise routine can have dramatic long-term results – as long as the exercise you choose is one which makes you breathless.

Using the latest cutting-edge techniques, researchers discovered that doing just 15 minutes a day of at least moderate exercise at age 12 led to 10-12% less body fat in boys and girls when they reached 14. The proviso is that the activity has to be vigorous enough to make your child a little out a breath to be of benefit.

What makes the results particularly interesting is that it involves following the same large group of UK children who were studied at two different times – two years apart. That, and the use of high-tech equipment, provides the most accurate measures of both fat and activity levels ever achieved for a study of this type.

Researchers monitored over 4,500 children from the Children of the 90s research project (also known as ALSPAC, the Avon Longitudinal Study of Parents and Children) initially at age 12 and then again at 14. The study is based at the University of Bristol

Each child wore a special ‘Actigraph activity monitor’, which sits on a belt around the waist and records every move they made. Most wore the movement-sensitive monitor for a week but all used the Actigraph for at least three days and activity levels were monitored for a period of 10 hours a day.

They also had their body fat measured using an X-ray emission scanner, which differentiates both muscle and fat deposits in the body. This is far more precise than the usual BMI (Body Mass Index) system often used to estimate fat levels.

Heading up the research is Professor Chris Riddoch from the University of Bath together with Children of the 90s’ co-director Professor Andy Ness and his team at Bristol.

Professor Riddoch explained the significance of their results, “Although this study spans only two years, the important thing is that we have a far clearer idea of the sequence of events. It is a really important link in the chain of evidence showing that inactivity leads to obesity, rather than obesity – for example caused by overeating – leading to inactivity.

“It is the strongest suggestion yet that we need to look at how active children are, rather than automatically blaming their diet, when we wonder about why children are become overweight and obese.”

(Photo: Bristol U.)

Bristol University


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For those who are deaf or hard of hearing, cell phone use has largely been limited to text messaging. But technology is catching up: Cornell researchers and colleagues have created cell phones that allow deaf people to communicate in sign language -- the same way hearing people use phones to talk.

"We completely take cell phones for granted," said Sheila Hemami, Cornell professor of electrical and computer engineering, who leads the research with Eve Riskin and Richard Ladner of the University of Washington. "Deaf people can text, but if texting were so fabulous, cell phones would never develop. There is a reason that we like to use our cell phones. People prefer to talk."

The technology, Hemami continued, is about much more than convenience. It allows deaf people "untethered communication in their native language" -- exactly the same connectivity available to hearing people, she said.

Since the project, Mobile ASL (American Sign Language), started four years ago, the researchers have published several academic papers on their technology and given talks around the world. The first phone prototypes were created last year and are now in the hands of about 25 deaf people in the Seattle area.

Standard videoconferencing is used widely in academia and industry, for example, in distance-learning courses. But the Mobile ASL team designed their video compression software specifically with ASL users in mind, with the goal of sending clear, understandable video over existing limited bandwidth networks. They also faced such constraints as phones' battery life and their ability to process real-time video at enough frames per second. They solved the battery life problem by writing software smart enough to vary the frames per second based on whether the user is signing or watching the other person sign.

Because ASL requires efficient motion capture, the researchers had to make video compression software that could deliver video at about 10 frames per second. They also had to work within the standard wireless 2G network, which only allows transmission of video at about 15-20 kilobits per second.

This is a relatively small amount of information when compared with a YouTube video, which travels at about 600 kilobits per second. For further comparison, high-definition digital television images come in at 6-10 megabits per second.

Researching how ASL developed gave the team clues on how people use it, said Frank Ciaramello, a graduate student working on the project. They learned that deaf people often use only one hand to sign, depending on the situation, and that they're very good at adapting as needed.

And they found that when two people are talking to each other, they spend almost the entire time focused on the other person's face.

"The facial expressions are really important in ASL, because they add a lot of information," Ciaramello said. They concluded that their cell phone video would have to be clearest in the face and hands, while they could spare some detail in the torso and in the background. Studies with deaf people who rated different videos on an intelligibility scale helped the researchers hone in on the best areas to focus in their video.

The researchers are now perfecting their intelligibility metrics while also looking for ways to bring down the cost of integrating the software into the phones. Making the phones as user friendly as possible is a key goal of the project, Hemami said.

"We don't want people to use the technology and say, 'This is annoying,'" Hemami said. "We want it to be really technology transparent. We want them to call their mother and have a nice conversation."

(Photo: Robert Barker/Cornell University)

Cornell University


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An international team of scientists led by researchers at the University of Hawaii at Manoa have found no evidence supporting an extraterrestrial impact event at the onset of the Younger Dryas ~13000 years ago.

The Younger Dryas is an abrupt cooling event in Earth's history. It coincided with the extinction of many large mammals including the woolly mammoth, the saber toothed jaguar and many sloths. This cooling period is generally considered to be the result of the complex global climate system, possibly spurred on by a reduction or slowdown of the thermohaline circulation in North America. This paradigm was challenged two years ago by a group of researchers that reported finding high iridium concentrations in terrestrial sediments dated during this time period, which led them to theorise that an impact event was instead the instigator of this climate shift. A team led by François Paquay, a Doctoral graduate student in the Department of Geology and Geophysics at the University of Hawaii at Manoa (UHM) decided to also investigate this theory, to add more evidence to what they considered a conceptually appealing theory. However, not only were they unable to replicate the results found by the other researchers, but additional lines of evidence failed to support an impact theory for the onset of the Younger Dryas. Their results were published in the December 7th early online edition of the prestigious journal the Proceedings of the National Academy of Sciences.

The idea that an impact event may have been the instigator for this cooling period was appealing because of several alleged impact markers, especially the high iridium concentrations that the previous team reported. However, it is difficult for proponents of this theory to explain why no impact crater of this age is known. "There is a black mat layer across North America which is correlated to the Younger Dryas climatic shift seen in Greenland ice cores dated at 13 thousand years ago by radio carbon," explains Paquay. "Initially I thought this type of layer could be associated with an impact event because concentration in the proxies of widespread wildfires are sky high. That plus very high levels of iridium (which is one indicator used to indicate extraterrestrial impact events). So the theory was conceptually appealing, but because of the missing impact site, the idea of one or multiple airburst arose."

To corroborate the theory, Paquay and his colleagues decided to take a three-pronged approach. The first was to replicate the original researchers data, the second step was to look for other tracers, specifically osmium isotopes, of extraterrestrial matter in those rocks, and the third step was to look for these concentrations in other settings. "Because there are so many aspects to the impact theory, we decided to just focus on geochemical evidence that was associated with it, like the concentration of iridium and other platinum group elements, and the osmium isotopes," says Paquay. "We also decided to look in very high resolution sediment cores across North America, and yet we could find nothing in our data to support their theory."

The team includes American, Belgian and Canadian researchers. Analysis of the sediments was done both at UHM and in Belgium, using the same sediments from the same interval and independently did the analysis work and got similar results. Both the marine and terrestrial sediment records do not indicate that an impact event was the trigger for the transition into the Younger Dryas cold period. "The marine and terrestrial record both complement each other to support this finding," concludes Paquay. "That's what makes the beauty of this study."

(Photo: Wikipedia Common)

University of Hawaii


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A coating on windows or solar panels that repels grime and dirt? Expanded battery storage capacities for the next electric car? New Tel Aviv University research, just published in Nature Nanotechnology, details a breakthrough in assembling peptides at the nano-scale level that could make these futuristic visions come true in just a few years.

Operating in the range of 100 nanometers (roughly one-billionth of a meter) and even smaller, graduate student Lihi Adler-Abramovich and a team working under Prof. Ehud Gazit in TAU's Department of Molecular Microbiology and Biotechnology have found a novel way to control the atoms and molecules of peptides so that they "grow" to resemble small forests of grass. These "peptide forests" repel dust and water — a perfect self-cleaning coating for windows or solar panels which, when dirty, become far less efficient.

"This is beautiful and protean research," says Adler-Abramovich, a Ph.D. candidate. "It began as an attempt to find a new cure for Alzheimer's disease. To our surprise, it also had implications for electric cars, solar energy and construction."

A world leader in nanotechnology research, Prof. Gazit has been developing arrays of self-assembling peptides made from proteins for the past six years. His lab, in collaboration with a group led by Prof. Gil Rosenman of TAU's Faculty of Engineering, has been working on new applications for this basic science for the last two years.

Using a variety of peptides, which are as simple and inexpensive to produce as the artificial sweetener aspartame, the researchers create their "self-assembled nano-tubules" in a vacuum under high temperatures. These nano-tubules can withstand extreme heat and are resistant to water.

"We are not manufacturing the actual material but developing a basic-science technology that could lead to self-cleaning windows and more efficient energy storage devices in just a few years," says Adler-Abramovich. "As scientists, we focus on pure research. Thanks to Prof. Gazit's work on beta amyloid proteins, we were able to develop a technique that enables short peptides to 'self-assemble,' forming an entirely new kind of coating which is also a super-capacitor."

As a capacitor with unusually high energy density, the nano-tech material could give existing electric batteries a boost — necessary to start an electric car, go up a hill, or pass other cars and trucks on the highway. One of the limitations of the electric car is thrust, and the team thinks their research could lead to a solution to this difficult problem.

"Our technology may lead to a storage material with a high density," says Adler-Abramovich. "This is important when you need to generate a lot of energy in a short period of time. It could also be incorporated into today's lithium batteries," she adds.

Coated with the new material, the sealed outer windows of skyscrapers may never need to be washed again — the TAU lab's material can repel rainwater, as well as the dust and dirt it carries. The efficiency of solar energy panels could be improved as well, as a rain shower would pull away any dust that might have accumulated on the panels. It means saving money on maintenance and cleaning, which is especially a problem in dusty deserts, where most solar farms are installed today.

The lab has already been approached to develop its coating technology commercially. And Prof. Gazit has a contract with drug mega-developer Merck to continue his work on short peptides for the treatment of Alzheimer's disease — as he had originally foreseen.

Tel Aviv University


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The collision between the Siberian Plate and North China Plate was a significant geological event in earth history, which led to the final closure of the Paleoasian Ocean and the formation of the Eurasian continent. Despite numerous research efforts in recent decades, the precise time of this event has remained a puzzle until now. New evidence in helping settle this issue is provided by Prof. Deng Shenghui and his colleagues in their paper newly published in Science in China (2009, vol.52).

Geological studies have demonstrated that during the early Paleozoic, an interval from 450-300 million year ago, the Siberian paleo-land was thousands kilometers away from the North China paleo-land, which is very different from their present situation. An immense ocean of thousands kilometers wide, namely the Paleoasian Ocean, separated these two paleo-lands. During the Carboniferous and Early Permian (about 360-270 million year ago), the North China paleo-land was located near the equator, where subtropic-tropic type of flora grew, named as "the Cathaysia Flora". In contrast, the Siberian paleo-land was located at high latitude, where temperate flora was distributed, known as "the Angara Flora". These two types of floras are very distinctive and do not mix with each other because of the geological barrier and their separate niches in different climatic zones.

Prof. Deng and his collaborators concluded that the time of the Paleoasian Ocean's disappearance is the end of the Permian, about 251 million years ago, based on their study of land plant fossils. Several years ago, Deng and his research group found many plant fossils from the rocks that were formed in the Late Permian during their stratigraphical and paleontological investigation in Heilongjiang, Northeast China. These fossils could be divided into two types after detailed identifications. One belongs to Angara Flora and the other to Cathaysia Flora. So, these plant fossils represent a mixed flora. The mixed flora implies that the Angara type plants lived together with some Cathaysia type plants at this location in the Late Permian. This means that the Paleoasian Ocean, once a barrier of plant immigration, must have disappeared in the Late Permian, and those plants grew previously in North China paleo-land now immigrated to the Siberian paleo-land. Therefore, Deng and his colleagues suggested that the Paleoasian Ocean finally closed at the end of the Late Permian, about 251 million years ago.

Prof. Deng is a paleontologist in the Research Institute of Petroleum Exploration and Development, PetroChina, which is the largest national oil corporation in China. In order to explore more oil and gas resources, many basic geological problems should be solved first, such as the forming age of the oil and gas-bearing rocks, the paleogeography, paleoclimate, and paleoecology etc. Fossils, fossilized bodies and traces of ancient animals and plants, play an extremely important role in study of these basic geological problems. Prof. Deng and his paleontological group focus on the researches of various fossils.

Science in Chine Press




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