'Biosensors' on Four Feet Detect Animals Infected With Bird Flu

mouse earns a water reward for choosing the odor of samples of feces infected with avian flu over a feces sample from ducks that were not infected.

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Blood hounds, cadaver dogs, and other canines who serve humanity may soon have a new partner ― disease detector dogs ― thanks to an unusual experiment in which scientists trained mice to identify feces of ducks infected with bird influenza. Migrating ducks, geese, and other birds can carry and spread flu viruses over wide geographic areas, where the viruses may possibly spread to other species.

Reported in Boston at the 240th National Meeting of the American Chemical Society (ACS), the proof-of-concept study may pave the way for development of biosensors-on-four-feet that warn of infection with influenza and other diseases.

"Based on our results, we believe dogs, as well as mice, could be trained to identify a variety of diseases and health conditions," said U.S. Department of Agriculture scientist Bruce A. Kimball, Ph.D., who presented the study results. The study was among nearly 8,000 scientific reports scheduled for presentation at the ACS meeting, one of the largest scientific gatherings of 2010.

"In fact, we envision two broad, real-world applications of our findings," Kimball added. "First, we anticipate use of trained disease-detector dogs to screen feces, soil, or other environmental samples to provide us with an early warning about the emergence and spread of flu viruses. Second, we can identify the specific odor molecules that mice are sensing and develop laboratory instruments and in-the-field detectors to detect them."

Kimball cited the likelihood that a suite of chemicals, rather than a single compound, are responsible for producing the difference in fecal odor between healthy and infected ducks. His team is investigating the use of instruments in detecting these so-called volatile, or gaseous, metabolites in animal feces. Once accomplished, they can use statistical techniques to sift through the data to determine the pattern of volatiles that indicate the presence of infection.

Kimball and colleagues from the Monell Chemical Senses Center trained inbred mice to navigate a maze and zero in on infected duck feces. The mice got a reward of water every time they correctly identified the infected sample and no reward when they zeroed in on feces from healthy ducks. Eventually, the mice became experts at identifying feces from infected ducks.

Magnetism's Subatomic Roots: Study of High-Tech Materials Helps Explain Everyday Phenomenon

A new theoretical physics model helps define the subatomic origins of ferromagnetism -- the everyday "magnetism" of compass needles and refrigerator magnets.

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The modern world -- with its ubiquitous electronic devices and electrical power -- can trace its lineage directly to the discovery, less than two centuries ago, of the link between electricity and magnetism. But while engineers have harnessed electromagnetic forces on a global scale, physicists still struggle to describe the dance between electrons that creates magnetic fields.

Two theoretical physicists from Rice University are reporting initial success in that area in a new paper in the Proceedings of the National Academy of Sciences. Their new conceptual model, which was created to learn more about the quantum quirks of high-temperature superconductors and other high-tech materials, has also proven useful in describing the origins of ferromagnetism -- the everyday "magnetism" of compass needles and refrigerator magnets.

"As a theorist, you strive to have exact solutions, and even though our new model is purely theoretical, it does produce results that match what's observed in the real world," said Rice physicist Qimiao Si, the lead author of the paper. "In that sense, it is reassuring to have designed a model system in which ferromagnetism is allowed."

Ferromagnets are what most people think of as magnets. They're the permanently magnetic materials that keep notes stuck to refrigerators the world over. Scientists have long understood the large-scale workings of ferromagnets, which can be described theoretically from a coarse-grained perspective. But at a deeper, fine-grained level -- down at the scale of atoms and electrons -- the origins of ferromagnetism remain fuzzy.

"When we started on this project, we were aware of the surprising lack of theoretical progress that had been made on metallic ferromagnetism," Si said. "Even a seemingly simple question, like why an everyday refrigerator magnet forms out of electrons that interact with each other, has no rigorous answer."

Si and graduate student Seiji Yamamoto's interest in the foundations of ferromagnetism stemmed from the study of materials that were far from ordinary.

Si's specialty is an area of condensed matter physics that grew out of the discovery more than 20 years ago of high-temperature superconductivity. In 2001, Si offered a new theory to explain the behavior of the class of materials that includes high-temperature superconductors. This class of materials -- known as "quantum correlated matter" -- also includes more than 10 known types of ferromagnetic composites.

Si's 2001 theory and his subsequent work have aimed to explain the experimentally observed behavior of quantum-correlated materials based upon the strangely correlated interplay between electrons that goes on inside them. In particular, he focuses on the correlated electron effect that occur as the materials approach a "quantum critical point," a tipping point that's the quantum equivalent of the abrupt solid-to-liquid change that occurs when ice melts.

The quantum critical point that plays a key role in high-temperature superconductivity is the tipping point that marks a shift to antiferromagnetism, a magnetic state that has markedly different subatomic characteristics from ferromagnetism. Because of the key role in high-temperature superconductivity, most studies in the field have focused on antiferromagnetism. In contrast, ferromagnetism -- the more familiar, everyday form of magnetism -- has received much less attention theoretically in quantum-correlated materials.

"So our initial theoretical question was, 'What would happen, in terms of correlated electron effects, when a ferromagnetic material moves through one of these quantum tipping points?" said Yamamoto, who is now a postdoctoral researcher at the National High Magnetic Field Laboratory in Tallahassee, Fla..

To carry out this thought experiment, Si and Yamamoto created a model system that idealizes what exists in nature. Their jumping off point was a well-studied phenomenon known as the Kondo effect -- which also has its roots in quantum magnetic effects. Based on what they knew of this effect, they created a model of a "Kondo lattice," a fine-grained mesh of electrons that behaved like those that had been observed in Kondo studies of real-world materials.

Si and Yamamoto were able to use the model to provide a rigorous answer about the fine-grained origins of metallic ferromagnetism. Furthermore, the ferromagnetic state that was predicted by the model turned out to have quantum properties that closely resemble those observed experimentally in heavy fermion ferromagnets.

"The model is useful because it allows us to predict how real-world materials might behave under a specific set of circumstances," Yamamoto said. "And, in fact, we have been able to use it to explain experimental observations on heavy fermion metals, including both the antiferromagnets as well as the less well understood ferromagnetic materials."

Hovering Bats Stay Aloft Using Swirling Vortices

Simplified representation of the strong vortices associated with the unsteady aerodynamics of bat flight at slow speeds. The vortices can be thought of as causing the surrounding air to rotate rapidly around them, and this motion around the LEV on top of the wing increases the lift force on it. Just like familiar, fixed-wing planes, the bat also leaves tip vortices in its wake, but the overall flow is further modified by the start vortices created at the beginning of the downstroke. (Credit: Image courtesy of University of Southern California)

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Honey bees and hummingbirds can hover like helicopters for minutes at a time, sucking the juice from their favorite blossoms while staying aloft in a swirl of vortices.

But the unsteady air flows they create for mid-air suspension – which hold the secrets to tiny robotic flying machines -- have also been observed for the first time in the flight of larger and heavier animals, according to Prof. Geoffrey Spedding of the Department of Aerospace and Mechanical Engineering at the University of Southern California and his colleagues at Lund University, Sweden.

In a follow-up study of bat aerodynamics, appearing in the February 29, 2008 issue of Science, Spedding and co-authors F. T. Muijres, L.C. Johansson, R. Barfield, M. Wolf and A. Hedenstrom were able to measure the velocity field immediately above the flapping wings of a small, nectar-eating bat as it fed freely from a feeder in a low-turbulence wind tunnel.

Researchers used a wind tunnel at Lund University specially crafted for research on bird flight on bats. Birds fly “at the spot” against a headwind, allowing detailed investigation of wing movements using high speed video cameras. It’s also possible to visualize the vortices around the wings and in the wake using fog as tracer particles.

“Thanks to a very reliable behavior pattern where bats learned to feed at a thin, sugar-filled tube in the wind tunnel, using the same flight path to get there every time, and the construction of side flaps on the feeder tube, we could make observations with bright laser flashes right at mid-wing without harming the bats,” Spedding reported in a commentary about the study. “Before this, we had no direct evidence of how the air moved over the wing itself in these small vertebrates.”

The researchers’ findings challenge quasi-steady state aerodynamic theory, which suggests that slow-flying vertebrates should not be able to generate enough lift to stay above ground, said Spedding, a professor of aerospace and mechanical engineering in the USC Viterbi School of Engineering.

Using digital particle image velocimetry, the researchers discovered that Pallas’ long-tongued bat, Glossophaga soricina, increased its lift by as much as 40 percent using a giant and apparently stable, re-circulating zone, known as a leading-edge vortex (LEV), which completely changed the effective airfoil shape.

How can the bats generate such high lift? One of the team members and lead author of the new study, Florian Muijres, explains: "The high lift arises because the bats can actively change the shape (curvature) by their elongated fingers and by muscle fibers in their membranous wing. A bumblebee cannot do this; its wings are stiff. This is compensated for by the wing-beat frequency. Bats beat their wings up to 17 times per second while the bumblebee can approach 200 wing-beats per second."

“The air flow passing over the LEV of a flapping wing left an amazingly smooth and ordered laminar disturbance at the trailing edge of the wing, and the LEV itself accounted for at least a 40 percent increment in lift,” Spedding noted in his commentary, “Leading Edge Vortex Improves Lift in Slow-Flying Bats.” The LEV makes a strong lift force, but it may be equally important that the smooth flow behind it may be associated with low, or at least not increased, drag.

“The sharp leading edge of the bat wing generates the LEV,” Spedding said, “while the bat’s ability to actively change its wing shape and wing curvatures may contribute to control and stability in the leading-edge vortex.”

Spedding and his colleagues believe observations of LEVs in active, unrestricted bat flight have important implications for overall aerodynamic theory and for the design of miniature robotic flight vehicles, which have been undergoing dramatic modifications in recent years.

“There’s much to be learned from bat flight about unsteady flows and forces on small bodies,” Spedding said. “We have suspected for a while that insects weren’t the only creatures affected by highly unsteady viscous air flows, but now we know that larger animals adapted for slow and hovering flight, such as these nectar-feeding bats, can – and perhaps must – use LEVs to enhance flight performance. So, if we wish to build a highly maneuverable, slow-flying surveillance plane, maybe it should flap its wings like a bat?”

The paper in Science is: Leading-Edge Vortex Improves Lift in Slow-Flying Bats, authors are F T Muijres, L C Johansson, R Barfield, M Wolf, G R Spedding and A Hedenström.

Miniature Auto Differential Helps Tiny Aerial Robots Stay Aloft

Microrobots could be used for search and rescue, agriculture, environmental monitoringEngineers at Harvard University have created a millionth-scale automobile differential to govern the flight of minuscule aerial robots that could someday be used to probe environmental hazards, forest fires, and other places too perilous for people.

Their new approach is the first to passively balance the aerodynamic forces encountered by these miniature flying devices, letting their wings flap asymmetrically in response to gusts of wind, wing damage, and other real-world impediments.

"The drivetrain for an aerial microrobot shares many characteristics with a two-wheel-drive automobile," says lead author Pratheev S. Sreetharan, a graduate student in Harvard's School of Engineering and Applied Sciences. "Both deliver power from a single source to a pair of wheels or wings. But our PARITy differential generates torques up to 10 million times smaller than in a car, is 5 millimeters long, and weighs about one-hundredth of a gram -- a millionth the mass of an automobile differential."

High-performance aerial microrobots, such as those the Harvard scientists describe in the Journal of Mechanical Design, could ultimately be used to investigate areas deemed too dangerous for people. Scientists at institutions including the University of California, Berkeley, University of Delaware, University of Tokyo, and Delft University of Technology in the Netherlands are exploring aerial microrobots as cheap, disposable tools that might someday be deployed in search and rescue operations, agriculture, environmental monitoring, and exploration of hazardous environments.

To fly successfully through unpredictable environments, aerial microrobots -- like insects, nature's nimblest fliers -- have to negotiate conditions that change second-by-second. Insects usually accomplish this by flapping their wings in unison, a process whose kinematic and aerodynamic basis remains poorly understood.

Sreetharan and his co-author, Harvard engineering professor Robert J. Wood, recognized that an aerial microrobot based on an insect need not contain complex electronic feedback loops to precisely control wing position.

"We're not interested so much in the position of the wings as the torque they generate," says Wood, an associate professor of electrical engineering at Harvard. "Our design uses 'mechanical intelligence' to determine the correct wing speed and amplitude to balance the other forces affecting the robot. It can slow down or speed up automatically to correct imbalances."

Sreetharan and Wood found that even when a significant part of an aerial microrobot's wing was removed, the self-correction engendered by their PARITy (Passive Aeromechanical Regulation of Imbalanced Torques) drivetrain allowed the device to remain balanced in flight. Smaller wings simply flapped harder to keep up with the torque generated by an intact wing, reaching speeds of up to 6,600 beats per minute.

The Harvard engineers say their passive approach to regulating the forces generated in flight is preferable to a more active approach involving electronic sensors and computation, which would add weight and complexity to devices intended to remain as small as lightweight as possible. Current-generation aerial microrobots are about the size and weight of many insects, and even make a similar buzzing sound when flying.

"We suspect that similar passive mechanisms exist in nature, in actual insects," Sreetharan says. "We take our inspiration from biology, and from the elegant simplicity that has evolved in so many natural systems."

Sreetharan and Wood's work was funded by the National Science Foundation.

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Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Harvard University, via EurekAlert!, a service of AAAS.

Ants Take on Goliath Role in Protecting Trees in the Savanna from Elephants

Ants are not out of their weight class when defending trees from the appetite of nature's heavyweight, the African elephant, a new University of Florida study finds.

Columns of angered ants will crawl up into elephant trunks to repel the ravenous beasts from devouring tree cover throughout drought-plagued East African savannas, playing a potentially important role in regulating carbon sequestration in these ecosystems, said Todd Palmer, a UF biology professor and co-author of a paper being published in the journal Current Biology.

"It really is a David and Goliath story, where these little ants are up against these huge herbivores, protecting trees and having a major impact on the ecosystems in which they live," Palmer said. "Swarming groups of ants that weigh about 5 milligrams each can and do protect trees from animals that are about a billion times more massive."

The mixture of trees and grasses that make up savanna ecosystems are traditionally thought to be regulated by rainfall, soil nutrients, plant-eating herbivores and fire, he said.

"Our results suggest that plant defense should be added to the list," he said. "These ants play a central role in preventing animals that want to eat trees from doing extensive damage to those trees."

While conducting research in the central highlands of Kenya, where hungry elephants have destroyed much of the tree cover, Palmer said he and his colleague and former UF post-doctoral student, Jacob Goheen, now a University of Wyoming zoology, physiology and botany professor, noticed that elephants rarely ate a widespread tree species known as Acacia drepanolobium where guardian ants aggressively swarm anything that touches the trees. But they would feed on other trees that did not harbor these ants.

The researchers decided to test whether these tiny ants were repelling the world's largest land mammal by serving as bodyguards for the tree in exchange for shelter and the food it supplied in the form of a sugary nectar solution. So they offered elephants at a wildlife orphanage a choice between these "ant plant" trees, with and without ants on the branches, and their favorite species of tree, the Acacia mellifera, to which the researchers added ants to some of its otherwise antless branches.

"We found the elephants like to eat the "ant plant" trees just as much as they like to eat their favorite tree species, and that when either tree species had ants on them, the elephants avoided those trees like a kid avoids broccoli," he Palmer said.

Also, the researchers removed ants from "ant trees" out in the field to see if elephants would attack them undefended, and a year later found much more damage than on trees with ants. Satellite images between 2003 and 2008 confirmed the ants were having a widespread, long-term effect throughout the savanna, he said.

The ants did not seem to annoy tree-feeding giraffes, who used their long tongues to swipe away them away from their short snouts, in marked contrast to the long nose or trunk on an elephant, Palmer said. The inside of an elephant's trunk is tender and highly sensitive to thousands of biting ants swarming up into it, he said.

"An elephant's trunk is a truly remarkable organ, but also appears to be their Achille's heel when it comes to squaring off with an angry ant colony," he said.

Because it appears that smell alerts elephants to avoid trees that are occupied by ants, it raises the question of whether ant odors might be applied to crops to deter elephants from feeding on them, just as DEET helps repel mosquitoes from people, he said.

"A big issue in east Africa is elephants damaging crops, which is one reason elephants have been harassed and sometimes killed," he said. "There's been a lot of interest in the conservation world about how to minimize the conflict elephants have with humans and particularly how to keep elephants from raiding agricultural fields."

One predicted outcome of global warming is more frequent and intense droughts, which will force desperate elephants to eat everything they can to survive, Palmer said "With more droughts, the extent to which elephants destroy and remove trees may increase and potentially shift the ecosystems back to grasslands," he said.

Ants' role in saving trees is critical with the interest in slowing the accumulation of greenhouse gasses since trees absorb carbon dioxide from the atmosphere, Palmer said.

"These 'ant plants' don't cover just a few hundred acres but are distributed throughout east Africa from southern Sudan all the way over to eastern Zaire and down through the horn of Africa and Tanzania," he said. "So they potentially play a big role in terms of regulating carbon dynamics in these ecosystems."

Physical Activity May Strengthen Children's Ability To Pay Attention

Charles Hillman and Darla Castelli, professors of kinesiology and community health, have found that physical activity may increase students' cognitive control -- or ability to pay attention -- and also result in better performance on academic achievement tests.

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As school districts across the nation revamped curricula to meet requirements of the federal “No Child Left Behind” Act, opportunities for children to be physically active during the school day diminished significantly.

Future mandates, however, might be better served by taking into account findings from a University of Illinois study suggesting the academic benefits of physical education classes, recess periods and after-school exercise programs. The research, led by Charles Hillman, a professor of kinesiology and community health and the director of the Neurocognitive Kinesiology Laboratory at Illinois, suggests that physical activity may increase students’ cognitive control – or ability to pay attention – and also result in better performance on academic achievement tests.
“The goal of the study was to see if a single acute bout of moderate exercise – walking – was beneficial for cognitive function in a period of time afterward,” Hillman said. “This question has been asked before by our lab and others, in young adults and older adults, but it’s never been asked in children. That’s why it’s an important question.”
For each of three testing criteria, researchers noted a positive outcome linking physical activity, attention and academic achievement.
Study participants were 9-year-olds (eight girls, 12 boys) who performed a series of stimulus-discrimination tests known as flanker tasks, to assess their inhibitory control.
On one day, students were tested following a 20-minute resting period; on another day, after a 20-minute session walking on a treadmill. Students were shown congruent and incongruent stimuli on a screen and asked to push a button to respond to incongruencies. During the testing, students were outfitted with an electrode cap to measure electroencephalographic (EEG) activity.
“What we found is that following the acute bout of walking, children performed better on the flanker task,” Hillman said. “They had a higher rate of accuracy, especially when the task was more difficult. Along with that behavioral effect, we also found that there were changes in their event-related brain potentials (ERPs) – in these neuroelectric signals that are a covert measure of attentional resource allocation.”
One aspect of the neuroelectric activity of particular interest to researchers is a measure referred to as the P3 potential. Hillman said the amplitude of the potential relates to the allocation of attentional resources.
“What we found in this particular study is, following acute bouts of walking, children had a larger P3 amplitude, suggesting that they are better able to allocate attentional resources, and this effect is greater in the more difficult conditions of the flanker test, suggesting that when the environment is more noisy – visual noise in this case – kids are better able to gate out that noise and selectively attend to the correct stimulus and act upon it.”
In an effort to see how performance on such tests relates to actual classroom learning, researchers next administered an academic achievement test. The test measured performance in three areas: reading, spelling and math.
Again, the researchers noted better test results following exercise.
“And when we assessed it, the effect was largest in reading comprehension,” Hillman said. In fact, he said, “If you go by the guidelines set forth by the Wide Range Achievement Test, the increase in reading comprehension following exercise equated to approximately a full grade level.
“Thus, the exercise effect on achievement is not statistically significant, but a meaningful difference.”
Hillman said he’s not sure why the students’ performance on the spelling and math portions of the test didn’t show as much of an improvement as did reading comprehension, but suspects it may be related to design of the experiment. Students were tested on reading comprehension first, leading him to speculate that too much time may have elapsed between the physical activity and the testing period for those subjects.
“Future attempts will definitely look at the timing,” he said. Subsequent testing also will introduce other forms of physical-activity testing.
“Treadmills are great,” Hillman said. “But kids don’t walk on treadmills, so it’s not an externally valid form of exercise for most children. We currently have an ongoing project that is looking at treadmill walking at the same intensity relative to a Wii Fit game – which is a way in which kids really do exercise.”
Still, given the preliminary study’s positive outcomes on the flanker task, ERP data and academic testing, study co-author Darla Castelli believes these early findings could be used to inform useful curricular changes.
“Modifications are very easy to integrate,” Castelli said. For example, she recommends that schools make outside playground facilities accessible before and after school.
“If this is not feasible because of safety issues, then a school-wide assembly containing a brief bout of physical activity is a possible way to begin each day,” she said. “Some schools are using the Intranet or internal TV channels to broadcast physical activity sessions that can be completed in each classroom.”
Among Castelli’s other recommendations for school personnel interested in integrating physical activity into the curriculum:

• scheduling outdoor recess as a part of each school day;
• offering formal physical education 150 minutes per week at the elementary level, 225 minutes at the secondary level;
• encouraging classroom teachers to integrate physical activity into learning.

An example of how physical movement could be introduced into an actual lesson would be “when reading poetry (about nature or the change of seasons), students could act like falling leaves,” she said.
The U. of I. study appears in the current issue of the journal Neuroscience. Along with Castelli and Hillman, co-authors are U. of I. psychology professor Art Kramer and kinesiology and community health graduate student Mathew Pontifex and undergraduate Lauren Raine.
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Adapted from materials provided by University of Illinois at Urbana-Champaign.

Satellite Collisions: What Can Be Done To Prevent Them In The Future?

A U.S.-operated Iridium satellite -- one of a 66-member commercial constellation of communications satellites -- and a Russian satellite designated Cosmos 2251 collided on February 10

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The recent collision involving an active U.S. commercial Iridium satellite and an inactive Russian Cosmos 2251 satellite in low Earth orbit has demonstrated an urgent need to establish a civil space traffic control system.
A U.S.-operated Iridium satellite -- one of a 66-member constellation of communications satellites -- and a Russian satellite designated Cosmos 2251 collided on February 10.
Both were completely destroyed, producing two large debris clouds. According to information from the U.S. Air Force’s Space Surveillance Network, over 500 pieces from the Cosmos satellite and 194 pieces from the Iridium satellite were now being tracked in two separate debris clouds.
Investigations are underway regarding the events leading up to the collision of the two spacecraft – with details still forthcoming -- yet the implications of the incident are in need of immediate discussion.

Data warning
“Unfortunately, it appears that there was data warning about the possibility of this collision beforehand,” noted Brian Weeden, Technical Consultant for Secure World Foundation. “However, it must be stressed that close approaches between satellites somewhere in Earth orbit occurs on almost a weekly basis…and until this event, have never before resulted in an actual collision.”
Weeden noted that in every case it is impossible to give a definite answer on whether or not two objects will actually collide, only probabilities and potential risks.
“Getting the right information to the right authorities in time to make the right avoidance maneuver decision is a very complicated process that doesn't entirely exist yet,” Weeden said. “The Secure World Foundation is working with many other organizations around the world to try and develop this process.”
That process involves the creation of a space traffic control system.

Increasingly congested environment
“This collision underscores in a dramatic way the importance of instituting an international civil space situational awareness (SSA) system as soon as possible,” said Dr. Ray Williamson Executive Director of Secure World Foundation.
Williamson said that such a civil SSA system could have been used to warn the Iridium operations managers of the danger of collision and allow them to take evasive action. “In the absence of reliable ways to clear debris from orbit, it will be increasingly important to follow all active satellites to prevent future preventable collisions,” he added.
Williamson said that the satellite collision has been spotlighted in a statement of the United States, delivered during the 46th Session of the Scientific and Technical Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) being held in Vienna.
That COPUOS statement explains: “Since space is becoming an increasingly congested environment, heightened space situational awareness as well as international cooperation between governments and industry is critical in the future.”
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Adapted from materials provided by Secure World Foundation, via Newswise.

Antibacterial Plaster Could Put A Clean Sheen On Walls

Scientists report development of a novel plaster with excellent sterilizing abilities and properties similar to traditional gypsum plaster.

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Scientists in China are reporting development and testing of new self-sanitizing plaster with more powerful antibacterial effects than penicillin. The material could be used in wall coatings, paints, art works and other products.

Liang-jie Yuan and colleagues note that plaster has been used for centuries as building material and surfaces for great works of art, including Michelangelo’s famed Sistine Chapel ceiling in Vatican City. The new, first-of-its kind plaster —formed from different ingredients from traditional gypsum plaster — still retains similar mechanical properties while having added antibacterial effects.
Lab tests showed that the so-called “supramolecular” plaster has a “very broad” antibacterial spectrum, killing five types of disease-causing bacteria. When compared with penicillin, the plaster was more effective at controlling growth of four kinds of bacteria, including dangerous Staphylococcus aureus and Escherichia coli. “It can be expected that the supramolecular plaster can be used for building, painting, coating and carving, and the coat, brick, or art ware constructed by the plaster do not need additive antiseptic or sterilization,” the authors say.
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Adapted from materials provided by American Chemical Society.

Compact Biosensor For Wide-ranging Applications Under Development

This portable magnetoresistive biosensor system utilizes an IC chip with an embedded giant magnetoresistance sensor array called the Bead ARray Counter (BARC). BARC detects paramagnetic microparticles that are used to label protein or DNA molecules of interest in a sandwich-based assay. The BARC chip is housed in an assay cartridge which contains an integrated fluid cell, microfludics bus and a PCMCIA connector to quickly interface with the compact Bead Array Sensor System (cBASS). cBASS includes a low power electromagnet, an automated fluidic system, and supporting electronics, all of which is controlled by a computer through a USB interface.

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Scientists at the Naval Research Laboratory (NRL) are partnering with industry to develop a sensor system for biomolecules that could make a significant contribution to a variety of fields such as healthcare, veterinary diagnostics, food safety, environmental testing, and national security.
NRL has developed a highly sensitive, portable biosensor system called the compact Bead Array Sensor System (cBASS®). This innovative instrument utilizes a special integrated sensor chip, called the Bead ARray Counter (BARC®), which contains an embedded array of giant magnetoresistive sensors. With 64, 200 µm diameter sensors on the chip, BARC® has the potential to detect 64 different target analytes.
Through the efforts of Dr. Lloyd Whitman, former head of the Surface Nanoscience and Sensor Technology Section at NRL, the NRL-developed technology has been licensed to Seahawk Biosystems Corporation in Rockville, Maryland, for further development in veterinary diagnostic, clinical diagnostic, and environmental applications.

Researchers at NRL began working on the magnetoelectronic biosensor concept more than a decade ago, under the leadership of Dr. Richard Colton and former NRL researcher Dr. David Baselt. Dr. Baselt used a quantum-mechanical effect called giant magnetoresistance (GMR). In simplistic terms, GMR materials are magnetic field-dependent resistors, i.e. their resistance changes when subjected to an externally applied magnetic field. GMR devices are typically constructed of alternating magnetic and non-magnetic metal thin-film multilayers that are only nanometers in thickness.
Dr. Baselt looked specifically at a type of GMR called multilayer GMR in which the resistance of two thin antiferromagnetically exchange-coupled layers, separated by a thin non-magnetic conducting layer, can be altered by changing the moments of the ferromagnetic layers from anti-parallel to parallel. This change decreases the spin-dependent interfacial scattering of charge carriers resulting in a decrease in the resistance of the GMR material.
Dr. Baselt realized this very sensitive phenomenon could have potential in the development of sensors for biological materials which are naturally biochemically specific, but are not usually magnetic. By attaching tiny paramagnetic particles to biomolecules, such as proteins or single-stranded DNA, scientists could then perform standard sandwich-type immuno or nucleic acid hybridization assays over the GMR sensors.
The GMR sensors, each covered with complementary protein or single-stranded DNA (the "probe"), could then detect the magnetically labeled biomolecules (the "target") the assays were designed to identify.
A decade in the making, the instrumentation that reads the BARC® chip is called the "compact Bead Array Sensor System" (cBASS®). NRL's current engineering team is led by Dr. Cy Tamanaha, working with Dr. Jack Rife, Mr. Matthew Kniller, and Mr. Michael Malito. The engineering team has worked to make many improvements to cBASS®, including:
• a new quick assembly assay cartridge with an integrated microfluidic cell, PCMCIA interface and kinematic microfluidics bus;
• an onboard fully automated fluidic valve and pumping system;
• a new electromagnet design with lower power requirements;
• a faster data exchange via USB with the controlling computer; and
• a rechargeable battery unit for enhanced portability (they have shrunk cBASS® down to approximately the size of a shoebox).

Ultimately, the success of the NRL's magnetoelectronic biosensor depends on the performance of the microbead label assays whose continued development is currently spearheaded by Dr. Shawn Mulvaney with the assistance of Ms. Kristina Myers. Over the past several years, NRL has made significant strides in surface biofunctionalization and assay development. With these advances, they have achieved high sensitivity and speed; low, non-specific binding with femtomolar DNA and attomolar protein detection, typically in less than 10 minutes.
One important characteristic of the NRL-developed assays is that the size of the microbead labels allows for either magnetoelectronic detection with GMR sensors, or optical enumeration with image processing software via a standard low-power microscope. The detection sensitivity under each method is nearly identical. However, there are differences in the two methods related to the size of the detection system and the cost of the consumables used.
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Adapted from materials provided by Naval Research Laboratory.

Robot Playmates Monitor Emotional State Of Children With Autism

Wired participant demonstrates plays the nerf basketball game.

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The day that robot playmates help children with autism learn the social skills that they naturally lack has come a step closer with the development of a system that allows a robot to monitor a child's emotional state.
"There is a lot of research going on around the world today trying to use robots to treat children with autism spectrum disorders (ASD). It has shown that the children are attracted to robots, raising the promise that appropriately designed robots could play an important role in their treatment," says Nilanjan Sarkar, associate professor of mechanical engineering at Vanderbilt University. "However, the efforts so far have been quite limited because they haven't had a way to monitor the emotional state of the children, which would allow the robot to respond automatically to their reactions."

If these limitations can be overcome, the use of robots to treat children with ASD could have a significant social and financial impact. One baby in every 150 born today in the United States is diagnosed with ASD, making it more common than pediatric cancer, diabetes and AIDS combined. Currently, treatment of these children involves a combination of behavioral, educational, physical, occupational and speech therapies, sometimes accompanied by medication for co-occurring conditions such as anxiety, irritability, bi-polar and other disorders. The average cost of caring for one person with autism for life is $3.2 million. In total, autism currently costs the U.S. more than $90 billion per year, and that cost is projected to double by 2017 due to the growing population of those affected.
Over the last five years, Sarkar has developed a method that uses physiological measurements, including heart rate, galvanic skin response, temperature and muscle response, to monitor the emotional state of individuals. His original motivation was to improve human-robot interactions. When his nephew was diagnosed with autism, however, Sarkar got the idea of applying the technique to aid children with ASD. So he sought out one of the leading authorities on the subject, Wendy Stone, professor of pediatrics and investigator at Vanderbilt's Kennedy Center, and they formed a partnership to develop this new approach.
"I'm always interested in creative ways to study and treat autism, so, when Nilanjan approached me, I was willing to listen," says Stone. "He had clearly done his homework and his proposal sounded like a great idea."
This fall, Sarkar and Stone published two papers – one in the IEEE Transactions on Robotics and one in the International Journal of Human-Computer Studies – that describe the results of their first set of experiments, which were conducted with six children ranging in age from 13 to 16 years who had been diagnosed with ASD. A battery of physiological sensors were attached to the participants and they were asked to play two games. One was the computer game Pong. The other was a variant of Nerf basketball with the hoop and backboard attached to the end of a robotic arm that moves it back and forth or up and down. Graduate students Changchun Liu and Karla Conn participated in the studies.
The researchers report that the physiological data they gathered can be used to develop an affective model for each individual that can predict his or her emotional states of liking, anxiety and engagement with an accuracy of better than 80 percent. Furthermore, they showed that this information can be used in real time to alter the game configuration in ways that significantly increase the children's degree of engagement.
"That's the part that really nailed me," says Stone, "that the robot can read the physiological cues of the person playing the game, control the distance and angle of the hoop, and that the person reported a more positive mood when the computer was responsive to his needs."
The ability to accurately monitor a child's emotional state is particularly important in treating ASD, Stone says: "Children with autism are not necessarily giving the kind of emotional cues that we know how to read. They are not necessarily good reporters of their inner feelings. If we know that the child is becoming upset or anxious, then we can help the child identify his or her own emotional state and implement strategies for monitoring and control. It is a concrete way to help them identify their own feelings."
One of the most encouraging results of their preliminary research was discovering that the affective model works accurately in different settings. The model was based on the readings they took as the children played Pong. The game was changed in several ways: Ball and paddle speeds were varied, and computer-based opponents of different skill levels were introduced. This allowed the researchers to induce emotions of interest, boredom, anxiety and engagement in each of the participants. The model was then used to predict how each child would react to changes in the computer game. When they switched to robot basketball, they found that the model's predictions were equally accurate.
"The model is about as good at identifying a child's emotional state as an experienced therapist. When a child gets a new therapist, as often happens, there is a learning curve as the new therapist gets to know the child, whereas the accuracy of the model should continue to improve over time," Sarkar points out.
A robot's ability to provide consistent and predictable responses should be particularly useful for treating ASD. Each child has individual triggers. For example, one child may not like direct eye contact. Another might be upset by loud voices and sounds. Yet another may react when people get too close. Once a particular trigger is identified, a robot could be programmed to increase the stimulus at such a gradual rate that the child doesn't notice it. The robot could also be programmed to back off when it senses that its responses are beginning to bother the child. In this fashion, it could build up the child's tolerance to the problem stimulus. "Robots can be programmed to respond with a consistency that is difficult for humans to achieve," Sarkar points out.
According to the autism expert, something that robots lack may also be an advantage in this setting. "I've always been interested in the idea of teaching social skills in a non-social situation that is less threatening. The children can be distracted by a lot of sensory stimuli coming at them. Social stimuli are particularly complex and can confuse them. So alternative methods of teaching that can subtract the social component could be very helpful as a beginning step," Stone says.
In the future, the researchers foresee technologies like robots and virtual reality environments as taking over some of the burden of the behavioral therapy that is one of the most time-consuming and expensive aspects of ASD treatment.
"This approach holds great promise," says Stone. "It will involve many steps and this is just the beginning. There are lots of different possible applications. So it is just a matter of finding the resources to explore them all."
The research was supported by a grant from the Marino Autism Research Institute.
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Adapted from materials provided by Vanderbilt University.

Slow Down: Those Lines On The Road Are Longer Than You Think

People grossly underestimate the length of dashed lines separate traffic lanes, new research shows.

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Take a guess -- how long are the dashed lines that are painted down the middle of a road?

If you’re like most people, you answered, “Two feet.”
The real answer is 10 feet. That’s the federal guideline for every street, highway, and rural road in the United States, where dashed lines separate traffic lanes or indicate where passing is allowed.
A new study has found that people grossly underestimate the length of these lines -- a finding which implies that we’re all misjudging distances as we drive, and are driving too fast as a result.

Dennis Shaffer, assistant professor of psychology at Ohio State University’s Mansfield campus, led the study, which appeared in the journal Perception & Psychophysics.
Shaffer and his colleagues tested more than 400 college students in three experiments. When asked to guess the length of the lines from memory, most answered two feet. Even when the students were standing some distance away from actual 10-foot lines or riding by them in a car, they judged the size to be the same: two feet.
“We were surprised, first, that people’s estimates were so far off, and second, that there was so little variability,” Shaffer said.
The finding holds implications for traffic safety. Each dashed line measures 10 feet, and the empty spaces in-between measure 30 feet. So every time a car passes a new dashed line, the car has traveled 40 feet. But in this study, people consistently judged the lines and the empty spaces to be the same size, claiming that both were two feet.
“This means that to most people, 40 feet looks like a lot less than 40 feet when they’re on the road,” Shaffer said. “People cover more ground than they think in a given period of time, so they are probably underestimating their speed.”
He acknowledges that the study will come as no surprise to transportation engineers, some of whom his team consulted with during the study. But this is the first study to quantify Americans’ misperceptions of the lines.
Shaffer began this research when he was a graduate student at Kent State University in 1995, and continued it while he was on the faculty of Arizona State University’s West Campus, and now at Ohio State. At each university, he and his colleagues measured lines on a variety of roads in the area.
Over those years, the federal guideline for line size has shrunk from 15 feet to 10 feet. Wherever the researchers went, they found all lines to be close to the federal guidelines of the time. In Arizona in 2000, for instance, some lines were 16 feet long instead of the expected 15.
But even back then -- when the federal guideline was 15 feet -- people still thought of lines as measuring only two feet.
“It was ridiculous,” Shaffer said. “We talked to different people in different states, over different years, and whether the lines were 15 feet or 10 feet, people still estimated them to be two feet.”
One possible explanation: as we drive, we look out far ahead the car for safety reasons, so the only lines we really see are faraway lines that look small.
Even though lines appear to expand as a car passes by, drivers can’t safely notice that effect. Rather, the first line we can comfortably look at while driving safely is some 120 feet ahead -- the fourth line ahead on the road. So perhaps we think that all lines are as small in reality as that one faraway line appears to be.
Some researchers have proposed the idea of “size constancy” to explain our perceptions -- meaning that we see an object as being the same size, no matter how close or far away it is, Shaffer said.
“That seems to be the case for lines on the road, because even if you know how long they are, they still look two feet,” he added. “To have a correct perception of the size of an object, you have to be familiar with the object in advance. And that’s the clincher. Very few people are familiar with the size of a line on the road in advance.”
In the first experiment, researchers gave participants a written test in which they were asked how long they believed the lines and the spaces in-between to be. In the second experiment, the researchers took a piece of paper that was the exact size and shape of a dashed line and taped it to the ground. Participants stood either 60 or 120 feet from the line, and looked at it at an angle close to their line of sight, as they would see it if they were driving down a road. In the third experiment, participants sat in the front or rear passenger seat of a car, and were asked to study the lines and spaces while a researcher drove down an actual road at either 25 or 60 miles per hour.
As to why everyone’s estimates were consistent in every experiment, Shaffer suspects that the answer has something to do with how our brains perceive geometry. Engineers design roads, buildings, and public spaces using Euclidian geometry -- the system of lines and angles first described by the ancient Greek mathematician Euclid. But this study and previous ones suggest that our brains perceive objects in a non-Euclidian way.
In the future, Shaffer will examine how people perceive the size of lines that are oriented at different angles -- as if seen by a driver approaching a bend in a road -- and how our perceptions affect our ability to judge the steepness of hills.
His coauthors on the paper included Andrew Maynor, formerly an undergraduate psychology student at Ohio State who is now a graduate student in labor and human resources in the Fisher College of Business; and Windy Roy, formerly an undergraduate psychology student at Arizona State University’s West Campus.
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Adapted from materials provided by Ohio State University.

Safety device or just a must-have gizmo? The parent’s dilemma over pre-teen mobile

"The Tobi phone, unlike most mobiles, can block any numbers sending unwanted text messages"

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It is the modern parental dilemma: at what age should you let your child have his or her first mobile phone? The answer could soon be in single figures with the introduction of a device aimed at “pre-teens”.
Samsung’s Tobi phone, released yesterday at a cost of between £70 and £80, is supposed to ease the minds of concerned parents with several safety features that will make it easier to call parents in an emergency and stop children receiving bullying text messages.
But it is also designed to appeal to primary school pupils, coming in “sweet pink” or “loyal blue” colours with a choice of on-screen themes based on animated characters and the ability to customise the back of the phone with a range of colourful designs. Samsung said that it would be marketing the device at parents but family groups doubt this.
“I’ve always thought that there is a potential market for phones with reduced functionality that can block images and phone numbers,” said John Carr, secretary of the Children’s Charities’ Coalition on Internet Safety. “What is not a good idea is increasing the pressure on parents through marketing to buy more branded goods. In essence, it will be the kids who pick up on it.”
Sue Palmer, author of Detoxing Childhood, which gives advice to parents on how to steer children through the problems of growing up, said: “We have a huge amount of child protection legislation which is protecting their bodies, but nobody is thinking about their minds.
“They’re being brainwashed and leeched on to think that the most important thing in the world is consumption, and their parents are now being brought into the act.”
Samsung defended the phone, saying that the advertising was “aimed squarely at parents” and that it had gained the support of some parents’ groups, such as the Children’s Safety Education Foundation. “A least it gives the parent a chance to sit down and think about the safety issue,” it said.
The Tobi, unlike most phones, can block senders of text messages, so a child can choose to stop receiving messages from a given phone number. Experts pointed out, however, that the phone also has Bluetooth technology, which gives an alternative way for someone to send malicious and offensive messages that cannot be blocked.
Mr Carr said: “Some horrible pictures, sometimes pornographic ones, of kids on the toilet or in the changing rooms, are swapped through Bluetooth.”
Mobile phone makers are finding it increasingly difficult to sell their products because consumer demand is slowing and because the vast majority of people already own a phone. Many pre-teen children are among the last who do not. Research by the regulator Ofcom last year suggested that 65 per cent of girls and 61 per cent of boys between the ages of 8 and 11 owned or had access to a mobile phone. But in the same age range, only 22 per cent of boys and 40 per cent of girls used a mobile phone every day.
Others pointed to health concerns. In 2005 Sir William Stewart, then chairman of the Health Protection Agency and the National Radiological Protection Board, recommended that 9 to 14-year-olds should make only short calls and that younger children should never use mobile phones.

Small talk The Mickey Mouse phone
A planned Disney service aimed at 8 to 14-year-olds was scrapped because of an “adverse retail environment”

Teddyphone
“Child-safety” phone for four-year-olds programmed to call only four numbers.

Hello Kitty phone
Launched last summer in pink. Sanrio insisted that it was aimed at older women

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Source: Times archives

Unique stamps on world’s natural treasures on display

"Collector’s delight: A visitor takes a look at the stamps displayed at a thematic exhibition that opened in Chennai on Thursday."

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CHENNAI: Every stamp displayed at the hall had a message to convey — protect the environment. Visitors to the thematic exhibition that opened in the city on Thursday got a glimpse into the natural treasures of the world and were educated about the need to preserve them.
Organised by South India Philatelists’ Association and Tamil Nadu Centre of ABK-AOTS Dosokai on the centre’s premises, to mark World Environment Day, the exhibition featured the collection of 11 philatelists under different themes.
Every inch of the wall was covered by a whopping number of over 8,000 stamps mounted in frames.
The collection of ABK-AOTS Dosokai’s chairman M.R.Ranganathan outlined the various causes of global warming, including deforestation and industrial pollution, and its consequences. The remedy and the global action to tackle the problem were also suggested through the stamps.
Gaurav Sethia, a school student, had an interesting collection on marine life in various countries such as Canada and Vietnam.
The stamps on rare species were accompanied by information on the marine life such as Gentoo Penguin is the fastest swimming bird.
Naturalist T.Murugavel’s collection on conservation of nature traced the history of mankind’s changing relationship with environment and degradation of natural resources. “I have added the adhesive of stamps on Koala bears printed in Australia as it also had the image of animal printed,” he said.
While butterflies dominated Norean Singh Nahar’s collection, others featured various kinds of pollution and flora and fauna.
South India Philatelists’ Association’s president G.Balakrishna Das said one of the participants had matched the stamps with photographs of the endangered species in his collection.
Earlier, inaugurating the exhibition, Principal Chief Postmaster General Indira Krishnakumar said the Postal Department created awareness of environmental conservation through release of stamps. Chief Conservator of Forests (Research) R.K.Ojha and Exnora International founder M.B.Nirmal participated in the programme.
The exhibition, which is open from 10 a.m. to 7 p.m. till Saturday, also has a dealers’ booth to facilitate purchase of stamps.

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Three-day thematic stamp exhibition features some rare collections.

Interested Or Deceptively Flirting? Observers Of First Dates Can Predict Outcome, Study Shows

"When it comes to assessing the romantic playing field -- who might be interested in whom -- men and women were shown to be equally good at gauging men's interest -- and equally bad at judging women's interest."

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When it comes to assessing the romantic playing field -- who might be interested in whom -- men and women were shown to be equally good at gauging men's interest during an Indiana University study involving speed dating -- and equally bad at judging women's interest.
Researchers expected women to have a leg up in judging romantic interest, because theoretically they have more to lose from a bad relationship, but no such edge was found.
"The hardest-to-read women were being misperceived at a much higher rate than the hardest-to-read men. Those women were being flirtatious, but it turned out they weren't interested at all," said lead author Skyler Place, a doctoral student in IU's Department of Psychological and Brain Sciences working with cognitive science Professor Peter Todd. "Nobody could really read what these deceptive females were doing, including other women."
Place's study, published in the January issue of the journal Psychological Science, focused on the ability of observers to judge romantic interest between others because this ability has evolutionary benefits when it comes to finding a mate. Decisions that other people around us make, said Place, can influence or inform our own choices.
"So, if you walk into a room and there's 20 people you've never met before, being able to know which individuals might be available and which are clearly smitten by others can make you more efficient in finding your own romantic interest to pursue," he said.
For the study, 28 women and 26 men of college age watched video clips of couples interacting on speed dates. Speed dating is a popular commercial method for singles to meet a large number of individuals in one evening of successive brief one-on-one conversations. Each participant observed 24 videos, all with different men and women, and after each rated whether the man seemed interested in the woman and the woman in the man.
The speed dating sessions were all conducted in Germany while the observer ratings were all made by students in Indiana. Despite the language difference, observers were still able to judge men's romantic interest accurately using body language, tone of voice, eye contact, how often each dater spoke and other non-verbal cues.
"How people talk might convey more than what they say," Place said.
Observers did not have to see much of this non-verbal behavior. They were just as good at predicting the speed-dating couple's interest if they saw only 10 seconds of the date as they were if they saw 30 seconds. The researchers say this showed that observers, even with limited information, could make quick, accurate inferences using "thin slices" of behavior.
There was, however, great variability in how well observers could predict the interest of any particular speed-dater, ranging from 90 percent accuracy down to 10 percent. In five of the videos, 80 percent of the observers thought the women shown were interested when in fact they were not -- they were acting friendly even though they had no interest in the men.
Evolutionary theory, said Place, predicts a certain level of coyness or even deceptiveness in women because if a relationship is abandoned they may face greater costs, including pregnancy and child rearing. When choosing a mate, it is in a woman's best interest to get men to open up and talk honestly to give her a better idea of whether they would be good long-term partners.
"In a speed dating environment, you would expect to see these effects dramatically, with the women trying to get the men to be more straightforward, while they themselves remain more coy," Place said. "Though the pace is faster than a typical first date, the strategy remains the same."
Readers can see how successful they are at judging romantic interest by participating in a new online study that contains the same task as the one described here. To learn more or to participate in the 20-minute experiment being conducted by Place and his research colleagues, visit this site: https://www.indiana.edu/~abcwest/webexp/.
Co-authors include Peter M. Todd, Cognitive Science Program, in the College of Arts and Sciences at IU Bloomington; Lars Penke, University of Edinburgh in Scotland; and Jens B. Asendorpf, Humboldt University of Berlin.
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Adapted from materials provided by Indiana University.