Thursday, November 5, 2009

NC STATE DEVELOPS MATERIAL THAT COULD BOOST DATA STORAGE, SAVE ENERGY

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North Carolina State University engineers have created a new material that would allow a fingernail-size computer chip to store the equivalent of 20 high-definition DVDs or 250 million pages of text, far exceeding the storage capacities of today’s computer memory systems.

Led by Dr. Jagdish “Jay” Narayan, John C.C. Fan Family Distinguished Professor of Materials Science and Engineering and director of the National Science Foundation Center for Advanced Materials and Smart Structures at NC State, the engineers made their breakthrough using the process of selective doping, in which an impurity is added to a material that changes its properties. The process also shows promise for boosting vehicles’ fuel economy and reducing heat produced by semiconductors, a potentially important development for more efficient energy production.

Working at the nanometer level — a pinhead has a diameter of 1 million nanometers — the engineers added metal nickel to magnesium oxide, a ceramic. The resulting material contained clusters of nickel atoms no bigger than 10 square nanometers, a 90 percent size reduction compared to today’s techniques and an advancement that could boost computer storage capacity.

“Instead of making a chip that stores 20 gigabytes, you have one that can handle one terabyte, or 50 times more data,” Narayan says.

Information storage is not the only area where advances could be made. By introducing metallic properties into ceramics, Narayan says engineers could develop a new generation of ceramic engines able to withstand twice the temperatures of normal engines and achieve fuel economy of 80 miles per gallon. And since the thermal conductivity of the material would be improved, the technique could also have applications in harnessing alternative energy sources like solar energy.

The engineers’ discovery also advances knowledge in the emerging field of “spintronics,” which is dedicated to harnessing energy produced by the spinning of electrons. Most energy used today is harnessed through the movement of current and is limited by the amount of heat that it produces, but the energy created by the spinning of electrons produces no heat. The NC State engineers were able to manipulate the nanomaterial so the electrons’ spin within the material could be controlled, which could prove valuable to harnessing the electrons’ energy. The finding could be important for engineers working to produce more efficient semiconductors.

North Carolina State University

ETHIOPIA 27 MILLION YEARS AGO HAD HIGHER RAINFALL, WARMER SOIL

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Thirty million years ago, before Ethiopia's mountainous highlands split and the Great Rift Valley formed, the tropical zone had warmer soil temperatures, higher rainfall and different atmospheric circulation patterns than it does today, according to new research of fossil soils found in the central African nation.

Neil J. Tabor, associate professor of Earth Sciences at SMU and an expert in sedimentology and isotope geochemistry, calculated past climate using oxygen and hydrogen isotopes in minerals from fossil soils discovered in the highlands of northwest Ethiopia. The highlands represent the bulk of the mountains on the African continent.

Tabor's research supplies a picture of the paleo landscape of Ethiopia that wasn't previously known because the fossil record for the tropics has not been well established. The fossils were discovered in the grass-covered agricultural region known as Chilga, which was a forest in prehistoric times. Tabor's research looked at soil fossils dating from 26.7 million to 32 million years ago.

Fossil plants and vertebrates in the Chilga Beds date from 26.7 million to 28.1 million years ago, Tabor says. From his examination, Tabor determined there was a lower and older layer of coal and underclay that was a poorly drained, swampy landscape dissected by well-drained Oxisol-forming uplands. A younger upper layer of the Chilga Beds consists of mudstones and sandstones in what was an open landscape dominated by braided, meandering fluvial stream systems.

Tabor is part of a multi-disciplinary team combining independent lines of evidence from various fossil and geochemical sources to reconstruct the prehistoric climate, landscape and ecosystems of Ethiopia, as well as Africa.

(Photo: SMU)

Thirty million years ago, before Ethiopia's mountainous highlands split and the Great Rift Valley formed, the tropical zone had warmer soil temperatures, higher rainfall and different atmospheric circulation patterns than it does today, according to new research of fossil soils found in the central African nation.

Neil J. Tabor, associate professor of Earth Sciences at SMU and an expert in sedimentology and isotope geochemistry, calculated past climate using oxygen and hydrogen isotopes in minerals from fossil soils discovered in the highlands of northwest Ethiopia. The highlands represent the bulk of the mountains on the African continent.

Tabor's research supplies a picture of the paleo landscape of Ethiopia that wasn't previously known because the fossil record for the tropics has not been well established. The fossils were discovered in the grass-covered agricultural region known as Chilga, which was a forest in prehistoric times. Tabor's research looked at soil fossils dating from 26.7 million to 32 million years ago.

Fossil plants and vertebrates in the Chilga Beds date from 26.7 million to 28.1 million years ago, Tabor says. From his examination, Tabor determined there was a lower and older layer of coal and underclay that was a poorly drained, swampy landscape dissected by well-drained Oxisol-forming uplands. A younger upper layer of the Chilga Beds consists of mudstones and sandstones in what was an open landscape dominated by braided, meandering fluvial stream systems.

Tabor is part of a multi-disciplinary team combining independent lines of evidence from various fossil and geochemical sources to reconstruct the prehistoric climate, landscape and ecosystems of Ethiopia, as well as Africa.

(Photo: SMU)

Southern Methodist University

SPIRALING FLIGHT OF MAPLE TREE SEEDS INSPIRES NEW AERIAL SURVEILLANCE TECHNOLOGY

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Maple tree seeds (or samara fruit) and the spiraling pattern in which they glide to the ground have delighted children for ages and perplexed engineers for decades. Now aerospace engineering graduate students at the University of Maryland's Clark School of Engineering have learned how to apply the seeds unique design to devices that can hover and perform surveillance in defense and emergency situations.

In the 1950s, researchers first tried to create an unmanned aerial vehicle that could mimic a maple seed's spiraling fall. Ever since, their attempts have been foiled by instability, resulting in a lack of control over the tiny (less than one meter) vehicles, which were easily knocked off course by wind. As recently as June 2009, this was considered as an open challenge for engineers.

The Clark School students have solved the steering problem and provided a solution that allows the device to take off from the ground and hover, as well as perform controlled flight after its initial fall to the ground after being deployed from an aircraft. The device can also begin to hover during its initial descent, or after being launched by hand.

The students studied maple seeds and developed a new design incorporating the natural flight of the tiny flyers. The insight gleaned from this study enabled the creation of the world's smallest controllable single-winged rotorcraft. The maple seed-inspired design is valuable because when dropped, unpowered, from a plane and then controlled remotely, it can perform surveillance maneuvers for defense, fire monitoring and search-and-rescue purposes.

"Natural maple seeds usually trade off altitude for rotation as they fall to the ground," said Evan Ulrich, one of the graduate students on the team. This altitude-rotation trade-off results in the power that the seeds need to travel. But this traditional design does not provide enough power to allow the device to hover.

Ulrich and other graduate students in the research group led by Clark School Dean Darryll Pines (Professor, Department of Aerospace Engineering) incorporated a new part to their device, a curved, comma-shaped component in the body of the device, which provides more stability and gives the device power to hover. They have two patents pending on their innovation.

Part of the solution to controlling flight was to physically separate the problem of propulsion and stability. The wing of the vehicle is designed to function in the same way as natural samara and performs a stable autorotation during descent. The propulsive section of the vehicle functions like the tail rotor on a helicopter, though instead of preventing rotation, (as in the case of a helicopter), it maintains rotation (to allow it to hover).

Part of the solution to controlling flight was to physically separate the problem of propulsion and stability. The wing of the vehicle is designed to function in the same way as natural samara and performs a stable autorotation during descent. The propulsive section of the vehicle functions like the tail rotor on a helicopter, though instead of preventing rotation, (as in the case of a helicopter), it maintains rotation (to allow it to hover).

(Photo: Evan Ulrich/A. James Clark school of Engineering)

University of Maryland

EVOLUTION’S PATH MAY LEAD TO SHORTER, STOUTER WOMEN WHO GIVE BIRTH EARLIER

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Yale University researchers have detected the effects of natural selection among two generations of contemporary women and predict their descendents will be slightly shorter and chubbier, have lower cholesterol and blood pressure and have their first children earlier in life.

The predictions, which were made in the Oct. 19 online edition of the Proceedings of the National Academy of Sciences, were based on an analysis of women who have participated in the famous Framingham Heart Study, that began in 1948. The results illustrate the medical value of evolutionary biology principles, 150 years after Darwin published The Origin of the Species, the authors say.

“The idea that natural selection has stopped operating in humans because we have gotten better at keeping people alive is just plain wrong,” said Stephen C. Stearns, senior author of the paper and Edward P. Bass Professor of Ecology and Evolutionary Biology.

The reason is that traits that enable women to have children will continue to be subject to selection. As a first step, the Yale researchers measured the individual reproductive success of two generations of more than 2000 women who participated in the Framingham study and had reached menopause. They then surveyed the traits that conferred reproductive success. After adjusting for environmental factors such as income, education and lifestyle choices such as smoking, the researchers estimated the heritability of traits by applying correlations among all relatives. They also adjusted for the indirect effects of selection by measuring the impacts the traits have on each other – such as whether high blood pressure is correlated with lower or higher age of sexual maturity.

The statistical analysis allowed researchers to predict which of those traits were likely to be conferred by natural selection upon the third generation of women participating in the Framingham study. The results showed that the effects of natural selection are slow and gradual, but trend towards shorter, chubbier women with lower blood pressure and cholesterol and who give birth earlier in life. For instance, the women in the third generation of the study are predicted to begin their periods a month earlier and enter menopause a month later than their mothers and grandmothers.

However Stearns points out that the rate of change driven by natural selection found in this group of women does not differ much from rates observed in nature.

“The paper drives home the point that humans aren’t different, that we are evolving at about the same average rate as other life on the planet,” Stearns said.

Sean G. Byars, a post-doctoral researcher at Yale, was lead author of the paper. Researchers from the University of Pennsylvania and the Boston University School of Medicine contributed to the paper.

Yale University

BRAIN RESPONDS TO HUMAN VOICE IN ONE FIFTH OF A SECOND

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BBSRC-funded researchers have found that the sound of human voice can be recognised by the brain in less than one fifth of a second. The research could help scientists better understand conditions such as autism.

The study, conducted at the Centre for Cognitive Neuroimaging at the University of Glasgow, found that the brain recognises voices within a similar time-frame as it recognises faces – after around 170ms following presentation.

Ian Charest, a PhD student who conducted the study under the supervision of Professor Pascal Belin, said: “Because human social interactions rely heavily on facial and vocal expressions, the brain is likely to have developed the ability to process them very rapidly and efficiently. Since faces and voices are usually paired together in social communication, it makes sense that the brain would process them in a similar time-frame.”

Researchers tested 32 volunteers in an experiment in which electrical signals generated by the brain were measured using EEG caps as the volunteers listened to series of sounds comprising bird songs, environmental sounds and human voices.

They observed electric potentials related to voice that had twice the amplitude as those related to bird songs and environmental sounds in less than 200 milliseconds.

Ian, from Trois-Rivières, Québec, Canada added: “This knowledge may also help us understand conditions such as autism and help develop more accessible diagnostic tools. Autistic individuals have difficulties in social interactions and we observe abnormal brain activity after presentation of faces or voices in their brains.”

(Photo: BBSRC)

BBSRC

STUDY REVEALS HOW 'WORLD'S TOUGHEST BACTERIUM' SURVIVES LETHAL RADIATION

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Listed in the Guinness Book of World Records as "the world's toughest bacterium," Deinococcus radiodurans can withstand extreme temperatures and drought conditions, lack of nutrients and a thousand times more radiation than a human being.

A new study by Cornell researchers reveals that nitric oxide -- a gas molecule used in many metabolic processes in animals and a pollutant in the atmosphere that leads to smog -- plays a key role in D. radiodurans' recovery when exposed to ultraviolet radiation (UV).

The study, appearing online Oct. 19 in the Proceedings of the National Academy of Sciences, may have implications for why and how nitric oxides act as signals in mammals for cell-to-cell communication, dilation of the vascular system and activating the immune system; in bacterial responses to antibiotic treatments; and in food safety efforts as D. radiodurans appears in some canned foods. The organism is also studied for use in environmental cleanup of sites contaminated with radiation and toxic chemicals.
Brian Crane, a Cornell associate professor of chemistry and chemical biology, and colleagues, discovered a gene in D. radiodurans that, when exposed to UV radiation, increases production of an enzyme responsible for creating nitric oxide. They then engineered bacteria without this gene. When zapped by radiation, the engineered bacteria repaired themselves but failed to grow and proliferate.

"Bacteria are much more sensitive to radiation damage when nitric oxide is not there," said Crane, the paper's senior author. Bhumit Patel, a graduate student in Crane's lab, is the paper's first author. "If you block the nitric oxide signal, the cell will repair but [will] not divide," Crane added.

In addition, the researchers were surprised to find that removing nitric oxide increased sensitivity to radiation but had no effect on the bacteria's ability to withstand other stressors, including exposure to oxidative damage that leads to toxic free radicals.

They also found that under normal circumstances there is a time lag in the process, where radiation exposure induces the cell to repair itself, but it takes a few hours for these bacteria to produce nitric oxide, which then activates a gene involved in cell proliferation and stress responses. "Nitric oxide seems to coordinate this growth response, but it's curious that the bacteria will wait to grow until they have repaired themselves," said Crane. "We don't know why it works this way, but there are analogies in human cells [for other processes]. There may be related pathways for controlling cell growth in animal cells."

(Photo: U. Cornell)

University of Cornell

IS MY ROBOT HAPPY TO SEE ME?

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Scientists at Georgia Tech decided to test our ability to interpret a robot’s “emotion” by reading its expression to see if there were any differences between the ages. They found that older adults showed some unexpected differences in the way they read a robot’s face from the way younger adults performed. The findings will be presented at the upcoming Human Factors and Ergonomics Society 53rd Annual Meeting, Grand Hyatt, San Antonio, Texas on Thursday, October 22.

“Home-based assistive robots have the potential to help older adults age in place. They have the potential to keep older adults independent longer, reduce healthcare needs and provide everyday assistance,” said Jenay Beer, graduate student in Georgia Tech’s School of Psychology.

Beer, along with Wendy Rogers and Arthur Fisk, professors of Engineering Psychology at Georgia Tech and directors of the Human Factors and Aging Laboratory, used a virtual version of the iCat, called appropriately enough the virtual iCat, to test the difference among adults between the ages of 65 and 75 and 18 to 27. They had the virtual iCat exhibit seven emotions at various levels of intensity: happiness, sadness, anger, fear, surprise, disgust and neutral. They tested how well each participant could read the emotions of the virtual iCat.

Existing research on how well adults can recognize emotions on human faces has found that older adults are less accurate in recognizing anger, fear and sadness. But the robotic study found that older adults were less accurate in recognizing anger and fear, as expected, but had difficulty recognizing happiness, not sadness. In fact, they most often confused the happy expression with the neutral expression of the robot.

Beer reasoned that the similar success both younger and older adults had in recognizing sadness could be due to the difference in the way a human actually expresses an emotion and the way it’s exaggerated in art.

“It may be due to the ‘cartoon’ look of the iCat, with the mouth turned down being very prominent,” she said.

As for why the older adults had trouble recognizing the happy robot compared with their success in recognizing happy people, Beer suspected that the robot just didn’t do a good enough job of expressing its emotion.

“It may be that older adults were not as cognizant of the facial features differentiating happy from neutral,” she explained.

Researchers also found that neither the young nor old could easily distinguish the emotion disgust on the virtual iCat. Beer explained that this could be due to the difficulty in programming a robot to show this emotion.

“When humans express disgust, the nose is wrinkled and the lips are drawn back, creating creases on each side of the mouth,” said Beer. “Manipulating these wrinkles is difficult for a robot made with a plastic face.”

Beer is continuing her work by studying whether other virtual versions of robots show the same differences when compared to the virtual iCat and the human face. What seems clear already, though, is if robots are going to be accepted by older adults in any social situations, they need to be designed with emotion displays that are easy to recognize, with some of them potentially being exaggerated to overcome any trouble older adults may have in reading that emotion among human faces.

(Photo: GIT)

Georgia Tech

STUDY SHOWS HOW SUBSTANCE IN GRAPES MAY SQUEEZE OUT DIABETES

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A naturally produced molecule called resveratrol, found in the skin of red grapes, has been shown to lower insulin levels in mice when injected directly into the brain, even when the animals ate a high-fat diet.

The findings from a new UT Southwestern Medical Center study suggest that when acting directly on certain proteins in the brain, resveratrol may offer some protection against diabetes. Prior research has shown that the compound exerts anti-diabetic actions when given orally to animals with type 2 diabetes (non-insulin dependent diabetes mellitus), but it has been unclear which tissues in the body mediated these effects.

“Our study shows that the brain plays an important role in mediating resveratrol’s anti-diabetic actions, and it does so independent of changes in food intake and body weight,” said Dr. Roberto Coppari, assistant professor of internal medicine at UT Southwestern and senior author of the study appearing online and in the December issue of Endocrinology.

“These animals were overrun with fat and many of their organs were inflamed. But when we delivered resveratrol in the brain, it alleviated inflammation in the brain,” added Dr. Coppari.

Dr. Coppari emphasized that his study does not support the conclusion that consuming products made from red grapes, such as red wine, could alleviate diabetes.

“The main reason is that resveratrol does not cross the blood brain barrier efficiently,” he said. “In order for the brain to accumulate the same dose of resveratrol delivered in our study, the amounts of red wine needed daily would surely cause deleterious effects, especially in the liver. Rather, our study suggests that resveratrol’s analogs that selectively target the brain may help in the fight against diet-induced diabetes.”

For the study, the researchers investigated what happens when resveratrol acts only in the brain. Specifically, they wanted to know whether resveratrol injected in the brain activated a group of proteins called sirtuins, which are found throughout the body and thought to underlie many of the beneficial effects of calorie restriction. Previous animal research has shown that when these proteins are activated by resveratrol, diabetes is improved. In addition, drugs activating sirtuins currently are being tested as anti-diabetic medications in human trials, Dr. Coppari said.

In one group of animals, researchers injected resveratrol directly into the brain; another group received a saline-based placebo. All the surgically treated animals consumed a high-fat diet before and after the surgery.

Dr. Coppari said the insulin levels of the animals treated with the placebo solution rose increasingly higher post-surgery. “That’s a normal outcome because insulin sensitivity decreases the longer you keep an animal on a high-fat diet.”

Insulin levels in the mice given resveratrol, however, actually started to drop and were halfway to normal by the end of the five-week study period, even though the animals remained on a high-fat diet.

In addition, the researchers found that resveratrol did indeed activate sirtuin proteins in the brain.

Dr. Coppari said the findings support his team’s theory that the brain plays a vital role in mediating the beneficial effects of resveratrol and that manipulation of brain sirtuins also may have other beneficial outcomes. “By knowing that the central nervous system is involved, pharmaceutical companies can begin to focus on developing drugs that selectively target sirtuins in the brain,” he said.

The next step, Dr. Coppari said, is to determine precisely which neurons in the brain are mediating the effects of the resveratrol.

(Photo: UTSMC)

UT Southwestern Medical Center

ARCTIC SEDIMENTS SHOW THAT 20TH CENTURY WARMING IS UNLIKE NATURAL VARIATION

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The possibility that climate change might simply be a natural variation like others that have occurred throughout geologic time is dimming, according to evidence in a Proceedings of the National Academy of Sciences paper recently published.

The research reveals that sediments retrieved by University at Buffalo geologists from a remote Arctic lake are unlike those seen during previous warming episodes.

The UB researchers and their international colleagues were able to pinpoint that dramatic changes began occurring in unprecedented ways after the midpoint of the twentieth century.

"The sediments from the mid-20th century were not all that different from previous warming intervals," said Jason P. Briner, PhD, assistant professor of geology in the UB College of Arts and Sciences. "But after that things really changed. And the change is unprecedented."

The sediments are considered unique because they contain rare paleoclimate information about the past 200,000 years, providing a far longer record than most other sediments in the glaciated portion of the Arctic, which only reveals clues to the past 10,000 years.

"Since much of the Arctic was covered by big ice sheets during the Ice Age, with the most recent glaciations ending around 10,000 years ago, the lake sediment cores people get there only cover the past 10,000 years," said Briner.

"What is unique about these sediment cores is that even though glaciers covered this lake, for various reasons they did not erode it," said Briner, who discovered the lake in the Canadian Arctic while working on his doctoral dissertation. "The result is that we have a really long sequence or archive of sediment that has survived arctic glaciations, and the data it contains is exceptional."

Working with Briner and colleagues at UB who retrieved and analyzed the sediments, the paper's co-authors at the University of Colorado and Queens University, experts in analyzing fossils of bugs and algae, have pooled their expertise to develop the most comprehensive picture to date of how warming variations throughout the past 200,000 years have altered the lake's ecology.

"There are periods of time reflected in this sediment core that demonstrate that the climate was as warm as today," said Briner, "but that was due to natural causes, having to do with well-understood patterns of the Earth's orbit around the sun. The whole ecosystem has now shifted and the ecosystem we see during just the last few decades is different from those seen during any of the past warm intervals."

Yarrow Axford, a research associate at the University of Colorado, and the paper's lead author, noted: "The 20th century is the only period during the past 200 millennia in which aquatic indicators reflect increased warming, despite the declining effect of slow changes in the tilt of the Earth's axis which, under natural conditions, would lead to climatic cooling."

(Photo: U. Buffalo)

University at Buffalo

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