Interesting facts

Searching for Spin Liquids: Much-Sought Exotic Quantum State of Matter Can Exist

The world economy is becoming ever more reliant on high tech electronics such as computers featuring fingernail-sized microprocessors crammed with billions of transistors. For progress to continue, for Moore's Law -- according to which the number of computer components crammed onto microchips doubles every two years, even as the size and cost of components halves -- to continue, new materials and new phenomena need to be discovered.

Diagram depicting anti-ferromagnetic order (upper) compared to a spin liquid phase (lower). In an anti-ferromagnet, the spins are anti-aligned. A spin liquid has no order and the spins can be viewed as bobbing about like water molecules in liquid water. (Credit: E. Edwards)

Furthermore, as the sizes of electronic components shrink, soon down to the size of single atoms or molecules, quantum interactions become ever more important. Consequently, enhanced knowledge and exploitation of quantum effects is essential. Researchers at the Joint Quantum Institute (JQI) in College Park, Maryland, operated by the University of Maryland and the National Institute of Standards and Technology (NIST), and at Georgetown University have uncovered evidence for a long-sought-after quantum state of matter, a spin liquid. 


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Scientists Have New Help Finding Their Way Around Brain's Nooks and Crannies

Like explorers mapping a new planet, scientists probing the brain need every type of landmark they can get. Each mountain, river or forest helps scientists find their way through the intricacies of the human brain.

Scientists have found a way to use MRI scanning data 
to map myelin, a white sheath that covers some brain 
cell branches. Such maps, previously only available via 
dissection, help scientists determine precisely where they 
are at in the brain. Red and yellow indicate regions with 
high myelin levels; blue, purple and black areas have low 
myelin levels. (Credit: David Van Essen)

Researchers at Washington University School of Medicine in St. Louis have developed a new technique that provides rapid access to brain landmarks formerly only available at autopsy. Better brain maps will result, speeding efforts to understand how the healthy brain works and potentially aiding in future diagnosis and treatment of brain disorders, the researchers report in the Journal of Neuroscience Aug. 10.


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Seeing eye to eye is key to copying, say scientists

Imitation may be the sincerest form of flattery but how do our brains decide when and who we should copy? Researchers from The University of Nottingham have found that the key may lie in an unspoken invitation communicated through eye contact.

In a study published this week in the Journal of Neuroscience, a team of scientists from the University's School of Psychology show that eye contact seems to act as an invitation for mimicry, triggering mechanisms in the frontal region of the brain that control imitation. 

The results could be the first clues to understanding why some people, such as children with autism, struggle to grasp when they are expected to copy the actions of others in social situations. 


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Speaking and Understanding Speech Share the Same Parts of the Brain

The brain has two big tasks related to speech: making it and understanding it. Psychologists and others who study the brain have debated whether these are really two separate tasks or whether they both use the same regions of the brain. Now, a new study, published in the August issue of Psychological Science, a journal of the Association for Psychological Science, finds that speaking and understanding speech share the same parts of the brain, with one difference: we don't need the brain regions that control the movements of lips, teeth, and so on to understand speech.

New research finds that speaking and understanding 
speech share the same parts of the brain. 
(Credit: © Artsem Martysiuk / Fotolia)

Most studies of how speech works in the brain focuses on comprehension. That's mostly because it's easier to image the brains of people who are listening quietly; talking makes the head move, which is a problem when you're measuring the brain. But now, the Donders Institute at the Radboud University Nijmegen, where the study was conducted, has developed technology that allows recording from a moving brain. 

Laura Menenti, a Postdoctoral Research Associate at the University of Glasgow, co-wrote the paper along with Peter Hagoort of Radboud University Nijmegen and the Max Planck Institute for Psycholinguistics, Sarah Gierhan and Katrien Segaert. Menenti was initially interested in how the brain produces grammatical sentences and wanted to track the process of producing a sentence in its entirety; looking not only at its grammatical structure but also at its meaning. "What made this particularly exciting to us was that no one had managed to perform such a study before, meaning that we could explore an almost completely new topic," says Menenti. 


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Holograms Reveal Brain's Inner Workings: Microscopy Technique Used to Observe Activity of Neurons Like Never Before

Like far away galaxies, powerful tools are required to bring the minute inner workings of neurons into focus. Borrowing a technique from materials science, a team of neurobiologists, psychiatrists, and advanced imaging specialists from Switzerland's EPLF and CHUV report in The Journal of Neuroscience how Digital Holographic Microscopy (DHM) can now be used to observe neuronal activity in real-time and in three dimensions -- with up to 50 times greater resolution than ever before. The application has immense potential for testing out new drugs to fight neurodegenerative diseases such as Alzheimer's and Parkinson's.

This is a 3-D image of living neuron taken by DHM 
technology. (Credit: Courtesy of Lyncée Tec)

Neurons come in various shapes and are transparent. To observe them in a Petri dish, scientists use florescent dyes that change the chemical composition and can skew results. Additionally, this technique is time consuming, often damages the cells, and only allows researchers to examine a few neurons at a time. But these newly published results show how DHM can bypass the limitations of existing techniques. 

"DHM is a fundamentally novel application for studying neurons with a slew of advantages over traditional microscopes," explains Pierre Magistretti of EPFL's Brain Mind Institute and a lead author of the paper. "It is non-invasive, allowing for extended observation of neural processes without the need for electrodes or dyes that damage cells." 


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Biologists Discovery May Force Revision of Biology Textbooks: Novel Chromatin Particle Halfway Between DNA and a Nucleosome

Basic biology textbooks may need a bit of revising now that biologists at UC San Diego have discovered a never-before-noticed component of our basic genetic material.

Biologists have discovered a novel chromatin 
particle halfway between DNA and a nucleosome. 
While it looks like a nucleosome, it is in fact a 
distinct particle of its own, researchers say. 
(Credit: James Kadonaga, UC San Diego)

According to the textbooks, chromatin, the natural state of DNA in the cell, is made up of nucleosomes. And nucleosomes are the basic repeating unit of chromatin. 

When viewed by a high powered microscope, nucleosomes look like beads on a string. But in the Aug. 19 issue of the journal Molecular Cell, UC San Diego biologists report their discovery of a novel chromatin particle halfway between DNA and a nucleosome. While it looks like a nucleosome, they say, it is in fact a distinct particle of its own. 


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Etch-a-sketch with superconductors

Reporting in Nature Materials this week, researchers from the London Centre for Nanotechnology and the Physics Department of Sapienza University of Rome have discovered a technique to 'draw' superconducting shapes using an X-ray beam. This ability to create and control tiny superconducting structures has implications for a completely new generation of electronic devices.

In future, X-ray beams could be used to write superconducting circuits, such as those depicted in the image. Here, solid lines indicate electrical connections while semicircles denote superconducting junctions, whose states are indicated by red arrows. Credit: UCL Press Office

Superconductivity is a special state where a material conducts electricity with no resistance, meaning absolutely zero energy is wasted. 

The research group has shown that they can manipulate regions of high temperature superconductivity, in a particular material which combines oxygen, copper and a heavier, 'rare earth' element called lanthanum. Illuminating with X-rays causes a small scale re-arrangement of the oxygen atoms in the material, resulting in high temperature superconductivity, of the type originally discovered for such materials 25 years ago by IBM scientists. The X-ray beam is then used like a pen to draw shapes in two dimensions. 


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World-Record Pulsed Magnetic Field Achieved; Lab Moves Closer to 100-Tesla Mark

Researchers at the National High Magnetic Field Laboratory's Pulsed Field Facility at Los Alamos National Laboratory have set a new world record for the strongest magnetic field produced by a nondestructive magnet. 

Yates Coulter, left, and Mike Gordon of Los Alamos National Laboratory make final preparations before successfully achieving a world-record for the strongest magnetic field produced by a nondestructive magnet. Working at the National High Magnetic Field Laboratory's Pulsed Field Facility at Los Alamos, a team of researchers achieved a field of 97.4 tesla, which is nearly 100 times stronger than the magnetic field found in giant electromagnets used in metal scrap yards. (Credit: Image courtesy of DOE/Los Alamos National Laboratory)


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How Many Species On Earth? About 8.7 Million, New Estimate Says

Eight million, seven hundred thousand species (give or take 1.3 million).

Distribution of species by kingdom. (Credit: CoML)

That is a new, estimated total number of species on Earth -- the most precise calculation ever offered -- with 6.5 million species found on land and 2.2 million (about 25 percent of the total) dwelling in the ocean depths. 

Announced today by Census of Marine Life scientists, the figure is based on an innovative, validated analytical technique that dramatically narrows the range of previous estimates. Until now, the number of species on Earth was said to fall somewhere between 3 million and 100 million. 

Furthermore, the study, published by PLoS Biology, says a staggering 86% of all species on land and 91% of those in the seas have yet to be discovered, described and catalogued. 

Says lead author Camilo Mora of the University of Hawaii and Dalhousie University in Halifax, Canada: "The question of how many species exist has intrigued scientists for centuries and the answer, coupled with research by others into species' distribution and abundance, is particularly important now because a host of human activities and influences are accelerating the rate of extinctions. Many species may vanish before we even know of their existence, of their unique niche and function in ecosystems, and of their potential contribution to improved human well-being." 


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Researchers develop prototype to detect fake websites

Do you go online to pay bills, shop, transfer funds, sign up for classes, send email or instant messages or search for medical information? If so, then this pertains to you.

It seems logical that a more Internet-driven world would translate into a heightened awareness of fake websites. But it isn't so. The vast majority of people still are unable to determine the authenticity of websites, resulting in tremendous monetary loses. That is what is driving the work of UA Artificial Intelligence Lab members who, along with a UA alumnus, have earned a top honor from MIS Quarterly for their research.

Members of a University of Arizona Eller College of Management team and a UA alumnus developed a prototype system to detect fake websites. When tested against other existing commercial systems, the team found that its system resulted in effective and more accurate detections of spoof sites – better than a human can. 

The team's subsequent article, “Detecting Fake Websites: The Contribution of Statistical Learning Theory" was published last year in an issue of MIS Quarterly, or MISQ. A preeminent peer-reviewed journal in the field of management information systems, MISQ has since been named the article its top paper for 2010. 


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Scientists Discover Tipping Point for the Spread of Ideas

Scientists at Rensselaer Polytechnic Institute have found that when just 10 percent of the population holds an unshakable belief, their belief will always be adopted by the majority of the society. The scientists, who are members of the Social Cognitive Networks Academic Research Center (SCNARC) at Rensselaer, used computational and analytical methods to discover the tipping point where a minority belief becomes the majority opinion. The finding has implications for the study and influence of societal interactions ranging from the spread of innovations to the movement of political ideals.

In this visualization, we see the tipping point where minority opinion (shown in red) quickly becomes majority opinion. Over time, the minority opinion grows. Once the minority opinion reached 10 percent of the population, the network quickly changes as the minority opinion takes over the original majority opinion (shown in green). (Credit: SCNARC/Rensselaer Polytechnic Institute)

"When the number of committed opinion holders is below 10 percent, there is no visible progress in the spread of ideas. It would literally take the amount of time comparable to the age of the universe for this size group to reach the majority," said SCNARC Director Boleslaw Szymanski, the Claire and Roland Schmitt Distinguished Professor at Rensselaer. "Once that number grows above 10 percent, the idea spreads like flame." 


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New Way to Measure Expansion of Universe

Using a measurement of the clustering of the galaxies surveyed, plus other information derived from observations of the early universe, researchers have measured the Hubble constant with an uncertainly of less than 5 percent. The new work draws on data from a survey of more than 125,000 galaxies.

The 6df Galaxy Survey data, each dot is a galaxy and 
Earth is at the center of the sphere. (Credit: Image courtesy 
of International Centre for Radio Astronomy Research)

A PhD student from The International Centre for Radio Astronomy Research (ICRAR) in Perth has produced one of the most accurate measurements ever made of how fast the Universe is expanding. 

Florian Beutler, a PhD candidate with ICRAR at the University of Western Australia, has calculated how fast the Universe is growing by measuring the Hubble constant. 

"The Hubble constant is a key number in astronomy because it's used to calculate the size and age of the Universe," said Mr Beutler. 

As the Universe swells, it carries other galaxies away from ours. The Hubble constant links how fast galaxies are moving with how far they are from us. 


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Southampton engineers fly the world's first 'printed' aircraft

Engineers at the University of Southampton have designed and flown the world's first 'printed' aircraft, which could revolutionise the economics of aircraft design.

SULSA is the world's first "printed" aircraft.
Credit: University of Southampton

The SULSA (Southampton University Laser Sintered Aircraft) plane is an unmanned air vehicle (UAV) whose entire structure has been printed, including wings, integral control surfaces and access hatches. It was printed on an EOS EOSINT P730 nylon laser sintering machine, which fabricates plastic or metal objects, building up the item layer by layer. 

No fasteners were used and all equipment was attached using 'snap fit' techniques so that the entire aircraft can be put together without tools in minutes. 


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New Invisibility Cloak Hides Objects from Human View

For the first time, scientists have devised an invisibility cloak material that hides objects from detection using light that is visible to humans. The new device is a leap forward in cloaking materials, according to a report in the ACS journal Nano Letters.

A real-life invisibility cloak, shown in this cross- sectional 
illustration, can hide objects from human view. (Credit: ACS)

Xiang Zhang and colleagues note that invisibility cloaks, which route electromagnetic waves around an object to make it undetectable, "are still in their infancy." Most cloaks are made of materials that can only hide things using microwave or infrared waves, which are just below the threshold of human vision. To remedy this, the researchers built a reflective "carpet cloak" out of layers of silicon oxide and silicon nitride etched in a special pattern. The carpet cloak works by concealing an object under the layers, and bending light waves away from the bump that the object makes, so that the cloak appears flat and smooth like a normal mirror. 


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Brain Cap Technology Turns Thought Into Motion; Mind-Machine Interface Could Lead to New Life-Changing Technologies for Millions of People

"Brain cap" technology being developed at the University of Maryland allows users to turn their thoughts into motion. Associate Professor of Kinesiology José 'Pepe' L. Contreras-Vidal and his team have created a non-invasive, sensor-lined cap with neural interface software that soon could be used to control computers, robotic prosthetic limbs, motorized wheelchairs and even digital avatars.

University of Maryland associate professor of 
kinesiology Jose "Pepe" Contreras-Vidal wears his 
Brain Cap, a noninvasive, sensor-lined cap with neural 
interface software that soon could be used to control 
computers, robotic prosthetic limbs, motorized 
wheelchairs and even digital avatars. (Credit: John 
Consoli, University of Maryland)


"We are on track to develop, test and make available to the public- within the next few years -- a safe, reliable, noninvasive brain computer interface that can bring life-changing technology to millions of people whose ability to move has been diminished due to paralysis, stroke or other injury or illness," said Contreras-Vidal of the university's School of Public Health. 

The potential and rapid progression of the UMD brain cap technology can be seen in a host of recent developments, including a just published study in the Journal of Neurophysiology, new grants from the National Science Foundation (NSF) and National Institutes of Health, and a growing list of partners that includes the University of Maryland School of Medicine, the Veterans Affairs Maryland Health Care System, the Johns Hopkins University Applied Physics Laboratory, Rice University and Walter Reed Army Medical Center's Integrated Department of Orthopaedics & Rehabilitation. 

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Sun-Free Photovoltaics Powered by Heat

A new photovoltaic energy-conversion system developed at MIT can be powered solely by heat, generating electricity with no sunlight at all. While the principle involved is not new, a novel way of engineering the surface of a material to convert heat into precisely tuned wavelengths of light -- selected to match the wavelengths that photovoltaic cells can best convert to electricity -- makes the new system much more efficient than previous versions.</>

A variety of silicon chip micro-reactors developed by the MIT team. Each of these contains photonic crystals on both flat faces, with external tubes for injecting fuel and air and ejecting waste products. Inside the chip, the fuel and air react to heat up the photonic crystals. In use, these reactors would have a photovoltaic cell mounted against each face, with a tiny gap between, to convert the emitted wavelengths of light to electricity. (Credit: Photo by Justin Knight)

The key to this fine-tuned light emission, described in the journal Physical Review A, lies in a material with billions of nanoscale pits etched on its surface. When the material absorbs heat -- whether from the sun, a hydrocarbon fuel, a decaying radioisotope or any other source -- the pitted surface radiates energy primarily at these carefully chosen wavelengths. 


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How Vampire Bats Find Veins

Heat-sensing protein channels in vampire bats allow the flying mammals to find the best place to sink their teeth into their prey.

The common vampire bat (Desmodus rotundus)

Researchers have discovered an infrared-sensing protein channel that allows vampire bats to identify the hottest part of the animal—veins close to the skin’s surface that carry 38 degree-Celsius (100° F) blood, and presumably the best spot for feeding. 

The channel is a variant of TRPV1, a heat-sensing protein channel that is triggered by high temperatures that could potentially cause injury, according to the study published today (August 3) in Nature, and is distinct from the heat sensor used by snakes—the only other non-insect animals that are known to detect heat by sensing infrared radiation. 


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Engineers Solve Longstanding Problem in Photonic Chip Technology: Findings Help Pave Way for Next Generation of Computer Chips

Stretching for thousands of miles beneath oceans, optical fibers now connect every continent except for Antarctica. With less data loss and higher bandwidth, optical-fiber technology allows information to zip around the world, bringing pictures, video, and other data from every corner of the globe to your computer in a split second. But although optical fibers are increasingly replacing copper wires, carrying information via photons instead of electrons, today's computer technology still relies on electronic chips.

Caltech engineers have developed a new way to 
isolate light on a photonic chip, allowing light to 
travel in only one direction. This finding can lead 
to the next generation of computer-chip technology: 
photonic chips that allow for faster computers 
and less data loss. (Credit: Caltech/Liang Feng)

Now, researchers led by engineers at the California Institute of Technology (Caltech) are paving the way for the next generation of computer-chip technology: photonic chips. With integrated circuits that use light instead of electricity, photonic chips will allow for faster computers and less data loss when connected to the global fiber-optic network. 


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Engineers Reverse E. Coli Metabolism for Quick Production of Fuels, Chemicals

In a biotechnological tour de force, Rice University engineering researchers this week unveiled a new method for rapidly converting simple glucose into biofuels and petrochemical substitutes. In a paper published online in Nature, Rice's team described how it reversed one of the most efficient of all metabolic pathways -- the beta oxidation cycle -- to engineer bacteria that produce biofuel at a breakneck pace.

Rice University engineering researchers Ramon Gonzalez (left) and 
Clementina Dellomonaco reversed one of the most efficient of all 
metabolic pathways -- the beta oxidation cycle -- to engineer bacteria 
that make biofuels at a breakneck pace. (Credit: Jeff Fitlow/Rice 

Just how fast are Rice's single-celled chemical factories? On a cell-per-cell basis, the bacteria produced the butanol, a biofuel that can be substituted for gasoline in most engines, about 10 times faster than any previously reported organism. 


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Inexpensive catalyst that makes hydrogen gas 10 times faster than natural enzyme

Looking to nature for their muse, researchers have used a common protein to guide the design of a material that can make energy-storing hydrogen gas. The synthetic material works 10 times faster than the original protein found in water-dwelling microbes, the researchers report in the August 12 issue of the journal Science, clocking in at 100,000 molecules of hydrogen gas every second.

The part of the catalyst that cranks out 100,000
molecules of hydrogen gas a second packs electrons
into chemical bonds between hydrogen atoms, possibly
hijacked from water. Credit: PNNL

This step is just one part of a series of reactions to split water and make hydrogen gas, but the researchers say the result shows they can learn from nature how to control those reactions to make durable synthetic catalysts for energy storage, such as in fuel cells. 

In addition, the natural protein, an enzyme, uses inexpensive, abundant metals in its design, which the team copied. Currently, these materials -- called catalysts, because they spur reactions along -- rely on expensive metals such as platinum. 

"This nickel-based catalyst is really very fast," said coauthor Morris Bullock of the Department of Energy's Pacific Northwest National Laboratory. "It's about a hundred times faster than the previous catalyst record holder. And from nature, we knew it could be done with abundant and inexpensive nickel or iron." 


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Supergene is key to copycat butterflies

Since Charles Darwin, biologists have pondered the mystery of "mimicry butterflies", which survive by copying the wing patterns of other butterflies that taste horrible to their predators, birds. 

This undated handout photo released by the CNRS shows butterflies, Melinaea mneme (top) and Heliconius numata. The mystery of how a butterfly has changed its wing patterns to mimic neighbouring species and avoid being eaten by birds has been solved by a team of European scientists.

The answer, according to a study released on Friday, lies in an astonishing cluster of about 30 genes in a single chromosome. 

"We were blown away by what we found," said Mathieu Joron of France's National Museum of Natural History, who led the probe into what is being called a "supergene". 


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Computer learns language by playing games

Computers are great at treating words as data: Word-processing programs let you rearrange and format text however you like, and search engines can quickly find a word anywhere on the Web. But what would it mean for a computer to actually understand the meaning of a sentence written in ordinary English -- or French, or Urdu, or Mandarin?

"Civilization" is a strategy game in which players build
empires by, among other things, deciding where to
found cities and deploy armies. Image courtesy of
Sid Meier's Civilization V


One test might be whether the computer could analyze and follow a set of instructions for an unfamiliar task. And indeed, in the last few years, researchers at MIT’s Computer Science and Artificial Intelligence Lab have begun designing artificial-intelligence systems that do exactly that, with surprisingly good results. 

In 2009, at the annual meeting of the Association for Computational Linguistics (ACL), researchers in the lab of Regina Barzilay, associate professor of computer science and electrical engineering, took the best-paper award for a system that generated scripts for installing a piece of software on a Windows computer by reviewing instructions posted on Microsoft’s help site. At this year’s ACL meeting, Barzilay, her graduate student S. R. K. Branavan and David Silver of University College London applied a similar approach to a more complicated problem: learning to play “Civilization,” a computer game in which the player guides the development of a city into an empire across centuries of human history. When the researchers augmented an artificial-intelligence system so that it could use a player’s manual to guide the development of a game-playing strategy, its rate of victory jumped from 46 percent to 79 percent. 

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Early Warning Signal for Ecosystem Collapse: Fluctuations Before the Fall

Researchers eavesdropping on complex signals emanating from a remote Wisconsin lake have detected what they say is an unmistakable warning -- a death knell -- of the impending collapse of the lake's aquatic ecosystem. Researchers have found that models used to assess catastrophic changes in economic and medical systems can also predict environmental collapse. Stock market crashes, epileptic seizures, and ecological breakdowns are all preceded by a measurable increase in variance—be it fluctuations in brain waves, the Dow Jones index, or, in the case of the Wisconsin lake, chlorophyll.

A tale of two lakes: Paul (reference lake) is smaller lake; 
Peter (manipulated lake) in background. 
(Credit: Steve Carpenter)

The finding, reported April 29 in the journal Science by a team of researchers led by Stephen Carpenter, a limnologist at the University of Wisconsin-Madison, is the first experimental evidence that radical change in an ecosystem can be detected in advance, possibly in time to prevent ecological catastrophe. 

"For a long time, ecologists thought these changes couldn't be predicted," says Carpenter, a UW-Madison professor of zoology and one of the world's foremost ecologists. "But we've now shown that they can be foreseen. The early warning is clear. It is a strong signal." 

The implications of the National Science Foundation-supported study are big, says Carpenter. They suggest that, with the right kind of monitoring, it may be possible to track the vital signs of any ecosystem and intervene in time to prevent what is often irreversible damage to the environment. 

"With more work, this could revolutionize ecosystem management," Carpenter avers. "The concept has now been validated in a field experiment and the fact that it worked in this lake opens the door to testing it in rangelands, forests and marine ecosystems." 


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NASA's Swift and Hubble Probe Asteroid Collision Debris

Late last year, astronomers noticed an asteroid named Scheila had unexpectedly brightened, and it was sporting short-lived plumes. Data from NASA's Swift satellite and Hubble Space Telescope showed these changes likely occurred after Scheila was struck by a much smaller asteroid.

Top: Faint dust plumes bookend asteroid (596) 
Scheila, which is overexposed in this composite. 
Visible and ultraviolet images from Swift's UVOT 
(circled) are merged with a Digital Sky Survey 
image of the same region. The UVOT images 
were acquired on Dec. 15, 2010, when the asteroid 
was about 232 million miles from Earth. Bottom: 
The Hubble Space Telescope imaged (596) Scheila 
on Dec. 27, 2010, when the asteroid was about 
218 million miles away. Scheila is overexposed 
in this image to reveal the faint dust features. 
The asteroid is surrounded by a C-shaped cloud 
of particles and displays a linear dust tail in this 
visible-light picture acquired by Hubble's Wide 
Field Camera 3. Because Hubble tracked the asteroid 
during the exposure, the star images are trailed. 
(Credit: Top: NASA/Swift/DSS/D. Bodewits (UMD) / 
Bottom: NASA/ESA/D. Jewitt (UCLA))


"Collisions between asteroids create rock fragments, from fine dust to huge boulders, that impact planets and their moons," said Dennis Bodewits, an astronomer at the University of Maryland in College Park and lead author of the Swift study. "Yet this is the first time we've been able to catch one just weeks after the smash-up, long before the evidence fades away." 

Asteroids are rocky fragments thought to be debris from the formation and evolution of the solar system approximately 4.6 billion years ago. Millions of them orbit the sun between Mars and Jupiter in the main asteroid belt. Scheila is approximately 70 miles across and orbits the sun every five years. 

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New Solar Cell Technology Greatly Boosts Efficiency

With the creation of a 3-D nanocone-based solar cell platform, a team led by Oak Ridge National Laboratory's Jun Xu has boosted the light-to-power conversion efficiency of photovoltaics by nearly 80 percent.

Nanocone-based solar cell consisting of n-type 
nanocones, p-type matrix, transparent conductive 
oxide (TCO) and glass substrate. (Credit: Image)

The technology substantially overcomes the problem of poor transport of charges generated by solar photons. These charges -- negative electrons and positive holes -- typically become trapped by defects in bulk materials and their interfaces and degrade performance.

"To solve the entrapment problems that reduce solar cell efficiency, we created a nanocone-based solar cell, invented methods to synthesize these cells and demonstrated improved charge collection efficiency," said Xu, a member of ORNL's Chemical Sciences Division.

The new solar structure consists of n-type nanocones surrounded by a p-type semiconductor. The n-type nanoncones are made of zinc oxide and serve as the junction framework and the electron conductor. The p-type matrix is made of polycrystalline cadmium telluride and serves as the primary photon absorber medium and hole conductor.


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Cells Send Signals Via Membrane Nanotubes

Most of the body's cells communicate with each other by sending electrical signals through nano-thin membrane tubes. A sensational Norwegian research discovery may help to explain how cells cooperate to develop tissue in the embryo and how wounds heal.

Here a cell has coupled with another cell by growing 
a long nanotube which enables it to exchange 
electrical signals. (Credit: UiB)

For nearly ten years, researchers have known that cells can "grow" ultra-thin tubes named tunnelling nanotubes (TNTs) between one another. These nanotubes -- the length of two to three cells and just 1/500th the thickness of a human hair -- are connections that develop between nearly all cell types to form a communication channel different from any previously known mechanisms.

In 2010, Dr. Xiang Wang and Professor Hans-Hermann Gerdes -- colleagues at the University of Bergen's Department of Biomedicine -- discovered that electrical signals were being passed through nanotubes from one cell to another at high speed (roughly 1-2 m/sec). Their research receives funding under the Research Council's large-scale research programme Nanotechnology and New Materials (NANOMAT).


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Hydrogen Fuel Tech Gets Boost from Low-Cost, Efficient Catalyst

Scientists have engineered a cheap, abundant alternative to the expensive platinum catalyst and coupled it with a light-absorbing electrode to make hydrogen fuel from sunlight and water.


A team of researchers have engineered a cheap, abundant 
alternative to the expensive catalyst platinum and coupled it 
with a light-absorbing electrode to make hydrogen fuel from 
sunlight and water. The discovery was published in Nature 
Materials by theorist Jens Nørskov of the Department of 
Energy's SLAC National Accelerator Laboratory and Stanford 
University and a team of colleagues led by Ib Chorkendorff and 
Søren Dahl at the Technical University of Denmark. The team 
optimized a photo-electrochemical water splitting device by 
designing light absorbers made of silicon arranged in closely 
packed pillars, imaged above using a scanning electron 
microscope. After dotting the pillars with tiny clusters of the 
new catalyst and exposing the pillars to light, researchers 
watched as hydrogen gas bubbled up -- as quickly as if they'd 
used costly platinum. (Credit: Image courtesy of Christian D. 
Damsgaard, Thomas Pedersen and Ole Hansen, 
Technical University of Denmark)

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Shootingstars Provide Clues to Likely Response of Plants to Global Warming

Both migration and evolution played a role in the adaptation of shootingstars to warmer temperatures after the last ice age. Many scientists are concerned that plant and animal species may face extinction due to global warming, but biologists at Washington University in St. Louis are trying to predict exactly what will happen to them. Which species will migrate? Which evolve? Which change their behavior? Which become extinct?

A study of two rare species of shootingstar that grow in 
cliff habitats, the jeweled shootingstar (middle) and 
French's shootingstar (right) asked whether these are 
true species, glacial relicts now confined to refuge 
habitats, or variants of the widespread Mead's 
shootingstar (left) that adapted to 
the cliff microclimates. (Credit: Brad Oberle)


Rather than peer into the future, they are looking backward, exploring how species alive today survived global warming at the end of the Pleistocene and asking whether their responses provide any guidance for us today.

For his dissertation Brad Oberle, a doctoral candidate in biology in Arts & Sciences at Washington University in St. Louis, delved into the post-Pleistocene history of three species of shootingstars (Dodecatheon). 

Dodecatheon is a genus of flowering plant in the Primrose family, the petals of whose nodding flowers flex upward, giving the flowers the appearance of a star falling to earth, trailing flames behind it. 

Two of the species, the jeweled shootingstar (D. amethystinum), and French's shootingstar (D. frenchii), are rare and grow only in cliff habitats. 

Are the rare species glacial relicts, species adapted to the cool wet conditions during the Pleistocene that gradually retreated to smaller and smaller refuges as the climate warmed? Or were they ecotypes, local variants of a widespread species, Mead's shootingstar (D. meadia), that had adapted to cliff microclimates but were genetically similar to Mead's shootingstar. 

"As is typical of science," says Barbara A. Schaal, PhD, the Mary-Dell Chilton Distinguished Professor of biology in Arts & Sciences, Oberle's dissertation advisor, and his co-author, "the result was mixed. One species is probably a relict species, and the other is probably an ecotype. Some species responded to warming by migrating but other populations apparently adapted in place." 

The article was published in the April 5th issue of the Proceedings of the National Academy of Science (PNAS). 

"It's a lovely piece of work," Schaal says. 

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Why the Eye Is Better Than a Camera at Capturing Contrast and Faint Detail Simultaneously

The human eye long ago solved a problem common to both digital and film cameras: how to get good contrast in an image while also capturing faint detail.

Cones normally release the neurotransmitter glutamate 
in the dark, while light decreases glutamate release. This 
graph of neurotransmitter release shows what 
happens when cone cells are exposed to a dark spot in a 
light background (top) under various scenarios, including 
no feedback (green trace) and only negative feedback 
from horizontal cells (red trace). Negative feedback to 
many cones enhances edges, but would decrease 
detail in dark areas were it not for newly discovered 
positive feedback that is localized to only a few cone
cells (blue trace). (Credit: Richard Kramer lab, UC Berkeley)


Nearly 50 years ago, physiologists described the retina's tricks for improving contrast and sharpening edges, but new experiments by University of California, Berkeley, neurobiologists show how the eye achieves this without sacrificing shadow detail. 

"One of the big success stories, and the first example of information processing by the nervous system, was the discovery that the nerve cells in the eye inhibit their neighbors, which allows the eye to accentuate edges," said Richard Kramer, UC Berkeley professor of molecular and cell biology. "This is great if you only care about edges. But we also want to know about the insides of objects, especially in dim light." 

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