The free dolphin

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2012-02-11T13:28:00.000+01:00

Diamond light, brighter than the sun The Diamond Light source building at dusk. Credit: Diamond Light Source.

2012-02-11T13:18:00.000+01:00

The Diamond Light source building at dusk. Credit: Diamond Light Source.

It’s the size of five football pitches and generates light 10 billion times brighter than the sun. As the Diamond Light Source celebrates its tenth anniversary this year, Penny Bailey visits one of the UK’s biggest scientific investments to see how it works.

Imagine that the only thing limiting you is your imagination - that the physical means of achieving what you see in your mind's eye is right in front of you. That, according to Professor Mark Hodson, is how it is for scientists at the Diamond synchrotron in Oxfordshire. With its curving walls, lined with walkways, pipes and colourful, clunky-looking machines and gadgets, it's a sight that wouldn't seem out of place in an early episode of 'Doctor Who'.

From a birds-eye view, Diamond looks like a massive ring doughnut or a spaceship half a kilometre in circumference (roughly the size of five football pitches). In fact, it’s a polygon of 24 straight sides, and its size and shape are dictated by its purpose.

As the name suggests, Diamond is a source of intensely bright light, which can be up to 10 billion times brighter than the sun. And it's not just visible light - Diamond is optimised to produce light with much shorter wavelengths in the form of X-rays and also generates infrared and ultraviolet light invisible to the naked human eye.

Researchers go to the synchrotron to use that brilliantly intense light in much the same way as they use visible light in a microscope or X-rays: to reveal things we can't see. Microscopes work by passing visible (optical) light through an object. The refracted light passes through two lenses that focus it to create an image of the object's microscopic structures, then magnify the image so we can see it. An X-ray machine passes X-rays through an object and captures the image created of its internal tissues on negative film. X-rays reveal the internal composition (tissues) of large objects such as people, and microscopes reveal the innards of tiny objects such as cells that are only a few microns (0.001 mm) in size, too small to be visible to the naked human eye.

The Diamond synchrotron is millions of times bigger than an X-ray machine or a microscope, yet the light it generates enables scientists to see the internal structures of things that are infinitely smaller, such as atoms. Atoms are measured in angstroms: one angstrom (1 Å) is 0.1 of a nanometre (nm), which in turn is one-billionth of a metre. To give you some context, a human hair is 100 000 nm wide and an ant is approximately 5 million nm long.

In trying to look inside an atom, scientists are trying to visualize something that is only 0.1 billionth of a metre big. To distinguish two objects (atoms) that are only 1 Å apart, researchers need to pass a much more intense light through them. They need to use light with far shorter wavelengths than the visible light used in microscopes - either ultraviolet light or X-rays. It's the job of Diamond to produce that light and send it to the 'cabins', the laboratories surrounding the storage ring where the experiments are actually carried out.

Acceleration

How does Diamond create those intense, invisible forms of light? Like CERN in Switzerland, Diamond is a particle accelerator, and it uses very similar technology. Both, as the term suggests, are designed to get particles zipping along at great speed. CERN sends neutrons and protons smashing into each other at speeds approaching the speed of light to understand what particles - and the universe - are made of. Diamond, by contrast, accelerates electrons. It also doesn't smash them into each other, and scientists don't actually do any experiments with the electrons themselves; instead, they use the high speed of the electrons to create intense light to use in their experiments.

The way the electrons are produced in the first place will be familiar to anyone who's ever owned a big, old-fashioned TV. The cathode ray tube in the back of the TV heats up an alloy, causing it to release electrons and fire them at the TV screen, which fluoresces, producing images. Diamond works on a similar principle, although on a much vaster scale.

The bridge over the storage ring of the facility. Credit: Diamond Light Source.

Rather than a screen, the electrons generated by heating an alloy in an electron gun are fired into a sequence of three accelerators. The first is the 30-m long Linac, which increases the speed of electrons from almost no miles per hour to something approaching the speed of light. They then pass into the booster, where they gain energy until they have enough to produce light of the kind and quantity needed to illuminate the atoms the scientists are looking at.

They then pass into the storage ring - the vast 560 m2 tube that gives Diamond its shape and size. It is here that the electron bundles (beams), which travel around the ring roughly half a million times every second, generate synchrotron light and send it into the beamlines leading to the experimental stations (laboratories) surrounding the storage ring.

Magnets at the point of entry to the beamlines bend the speeding electrons around the corners of the polygonal storage ring, which causes them to release energy in the form of light (photons). This light spans the electromagnetic spectrum from infrared to visible and ultraviolet light and X-rays.

Diamond is a 'third-generation' synchrotron, which broadly means that it uses more sophisticated magnets to create more intense light. At the beamline point of entry, 'insertion devices' cause the electron beam to wiggle backwards and forwards between the opposite magnetic poles. This 'constructive interference' produces very bright, very intense beams of X-rays - so intense that safety procedures are stringent. People cannot enter the lead-lined hutches in which the experiments take place when the machine is operating, so experiments are controlled remotely from a separate control cabin.

The power of these X-rays can help reveal the atomic structure of proteins and inorganic elements like metals. Mirrors and crystals help focus the beams down to the wavelength required for each station, which then passes into the experimental hutch where it interacts with the substance the scientists want to 'see', the interaction revealing what it is made of at the atomic level.

Around 2000 research groups a year come to do experiments at Diamond that they could not do anywhere else. Research ranges from solving protein structures to designing drug targets.

Scientists have used the synchrotron's light to look at the nutritional quality of wheat, assess the success of attempts to increase levels of zinc and iron in food, and work out which form of phosphate is best at locking up metal contaminants in soil. iPod and iPad users might be interested to know that the technology on which they are based - giant magneto resistance - wouldn't exist without synchrotrons. With new beamlines coming online in the forthcoming third phase of Diamond's development, new possibilities for research abound to push the limits of scientists' imaginations.

Provided by Wellcome Trust (news : web)

Anyone can learn to be more inventive, cognitive researcher says

2012-02-11T13:11:00.002+01:00

There will always be a wild and unpredictable quality to creativity and invention, says Anthony McCaffrey, a cognitive psychology researcher at the University of Massachusetts Amherst, because an "Aha moment" is rare and reaching it means overcoming formidable mental obstacles. But after studying common roadblocks to problem-solving, he has developed a toolkit for enhancing anyone's skills.

McCaffrey believes his Obscure Features Hypothesis (OFH) has led to the first systematic, step-by-step approach to devising innovation-enhancing techniques to overcome a wide range of cognitive obstacles to invention. His findings appear now in an early online issue of Psychological Science. McCaffrey, a post doctoral research fellow at the Center for e-Design at UMass Amherst and Virginia Tech, recently won a two-year, $170,000 grant from the National Science Foundation to turn his technique into software with a user-friendly graphical interface. Initial users will likely be engineers.

Looking at more than 100 significant modern and 1,000 historical inventions, McCaffrey analyzed how successful inventors overcame various cognitive obstacles to uncover the key obscure information needed to solve problems. He found that almost all innovative solutions follow two steps, as articulated by the OFH: Noticing an infrequently-seen, obscure feature and second, building a solution based on that feature.

"I detected a pattern suggesting that something everyone else had overlooked often became the basis of an inventive solution," he says. So thecognitive psychologist with degrees in computer science and philosophy, who says all three disciplines "have come in very handy to approach this from different angles," set out to study aspects of human perception and cognition that inhibit our noticing obscure features.

"I felt that if I could understand why people overlook certain things, then develop techniques for them to notice much more readily what they were overlooking, I might have a chance to improve creativity."

Psychologists use the term "functional fixedness" to describe the first mental obstacle McCaffrey investigated. It explains, for example, how one person finding burrs stuck to his sweater will typically say, "Ugh, a burr," while another might say, "Hmmm, two things lightly fastened together. I think I'll invent Velcro!" The first view is clouded by focusing on an object's typical function.

To overcome functional fixedness, McCaffrey sought a way to teach people to reinterpret known information about common objects. For each part of an object, the "generic parts technique" (GPT) asks users to list function-free descriptions, including its material, shape and size. Using this, the prongs of an electrical plug can be described in a function-free way to reveal that they might be used as a screwdriver, for example.

"The trick is how to unconceal the features relevant to your purposes," McCaffrey points out. The result of creating the function-free parts list is a tree diagram in which the description of each part does not imply a use, helping subjects see beyond common functions of any object and its parts.

Using "insight problems" involving common objects because they require no special engineering knowledge, McCaffrey designed an experiment to test whether GPT improved problem solving in a group of 14 undergraduates trained in GPT compared to a control group of 14 who were not. Both groups were given insight problems commonly used in psychological testing, plus new ones designed by McCaffrey's colleagues.

Overall, the GPT group solved 67.4 percent more problems than the control group, a dramatic and statistically significant improvement in performance. In a follow-up study asking subjects to list features for the same objects (independent of a problem), GPT-trained subjects listed the key obscure feature required for the solution 75 percent of the time compared to 27 percent for controls. This suggests it is not mere exposure to problems but rather the GPT that leads to uncovering the key obscure feature more often.

Two ideas from his philosophy background helped him think about such problems in a broad way, McCaffrey says. In Nietzsche, McCaffrey found his broad definition of "feature" that doesn't limit a theory of creativity. From Heidegger, he borrowed the notion of "unconcealment," the idea that any object can have an unlimited number of features that are gradually unconcealed within an endless array of contexts.

"I was an elementary school teacher for several years," McCaffrey adds. "With these ideas bubbling around in my brain, I gave my students a steady stream of puzzles and observed carefully when they were getting stuck." Eventually, he decided it was time for him to formally and scientifically study how people overcome these mental obstacles.

"I want to help people to notice things consciously that they might not otherwise see, and remain open to the possibilities. Noticing is one thing, and building on it or connecting it to other things is the next step. Some of this can be learned and we now have a discipline for it." He is already looking at other obstacles and plans to publish a series of innovation-enhancing techniques to address as many as two dozen distinct creativity blocks caused by the normal function of our perceptual and cognitive systems.

Provided by University of Massachusetts at Amherst

Streams need trees to withstand climate change

2012-02-11T13:08:00.002+01:00

(PhysOrg.com) -- More than twenty years of biological monitoring have confirmed the importance of vegetation for protecting Australia's freshwater streams and rivers against the ravages of drought and climate change.

Researchers from Monash University, the Environment Protection Authority and the Arthur Rylah Institute for Environmental Research studied the effects of drought on Australia's fragile freshwater ecosystems using data collected in Victoria before, during and after the severe drought that lasted from 1997 until 2009.

The sustained monitoring allowed researchers to compare how sites with differing levels of vegetation responded to sustained drought.

The research, published in Global Change Biology, showed streams with extensive surrounding vegetation, whether natural or re-planted, were healthier, both in terms of water quality and biodiversity. These sites were much more robust in the face of drought than sparsely vegetated areas.

Dr. Ross Thompson, of the Australian Centre for Biodiversity at Monash University's School of Biological Sciences, said the results provided clues as to how Australia's waterways and surrounding areas would respond toclimate change.

"Changing climate is a reality, and even with current efforts to manage carbon emissions it will take decades to reverse the patterns of warming which we are already seeing. It's incredibly important to understand how we can better manage the environment in the face of this challenge," Dr. Thompson said.

Climate change is expected to cause reduced river flows through decreased or more variable rainfall. Extreme weather events, such as drought are expected to become more frequent and severe. This would be exacerbated by increasing agricultural demands for water.

Dr Thompson said reduced river flow would impact water quality, aquatic habitat, and the ability of organisms to move around in an ecosystem. These effects would likely be aggravated by human activity, and together with rising water temperatures would have a negative impact on biodiversity.

"This study shows that replanting vegetation around streams not only acts to absorb carbon from the atmosphere, helping us arrest climate change in the future, but may also work now to protect biodiversity through providing cool refuges and protecting habitat in warming landscapes," Dr. Thompson said.

The research was supported by an Australian Research Council Linkage grant, with Monash University working in partnership with state and regional policy and management agencies.

Provided by Monash University (news : web)

A frank discussion of the power law and linking correlation to causation

2012-02-11T13:04:00.000+01:00

An example power-law graph, being used to demonstrate ranking of popularity. To the right is the long tail, and to the left are the few that dominate (also known as the 80-20 rule). Image: Wikipedia.

(PhysOrg.com) -- Michael Stumpf a mathematics professor at Imperial College in London, and Mason Porter a lecturer at Oxford have teamed together to write and publish a perspective piece in Science regarding the inexact science of trying to apply the power law to situations in science where it’s not always easy to show a direct link between correlation and causation, a key problem they say, in much of the science that is conducted today.

A power law is where a relationship between two quantities exists that can be described mathematically where one measurement is directly related to the outcome of another. In their perspective the authors describe it as related via an exponent which can be mathematically described. One example is where the surface area of a sphere is firmly fixed to its radius, i.e. the area increases proportionally as the radius does. In such cases, its scalable, it doesn’t matter how large or small the sphere is, its surface area can still be calculated using the same formulaic relationship. It’s also meaningful, i.e. the relationship formula can be used to actually calculate sphere surface areas.

In their perspective, the authors use the relationship between the metabolic performance of an organism and its body size, which biologists describe using allometric scaling, a power law, to make their assertions. Research has shown that using such a formula allows scientists to calculate the second when obtaining the first through measurement, regardless of body size, a clear and useful thing when studying virtually any organism.

In their perspective, however, the authors point out that not all areas of science are so compliant, which leads to all manner of assumptions regarding outcomes that may or may not be true. One prime example is when researchers collect data points and find they can draw a line though them, which suggests a correlation. Unfortunately, quite often other lines could have just as easily been drawn, indicating there was no correlation at all. The point here is that in scenarios where the power law cannot be applied, researchers are often left to make educated guesses, going on little more than intuitive leaps based on past experience. This is especially important when it is a practicable impossibility to obtain a reasonably large sample size.

They also point out that many instances occur in research where the power law is applied in ways that don’t actually make sense. For example, if a line is drawn though a set of data points showing correlation, it won’t matter much if that line doesn’t offer any real insight into what is being demonstrated.

Because of such scenarios, the authors conclude that it might behoove the scientific community, both researchers and readers of scientific papers alike, to apply some bit of skepticism to such claims when they are made.

More information: Critical Truths About Power Laws, Science 10 February 2012: Vol. 335 no. 6069 pp. 665-666. DOI: 10.1126/science.1216142

The ability to summarize observations using explanatory and predictive theories is the greatest strength of modern science. A theoretical framework is perceived as particularly successful if it can explain very disparate facts. The observation that some apparently complex phenomena can exhibit startling similarities to dynamics generated with simple mathematical models (1) has led to empirical searches for fundamental laws by inspecting data for qualitative agreement with the behavior of such models. A striking feature that has attracted considerable attention is the apparent ubiquity of power-law relationships in empirical data. However, although power laws have been reported in areas ranging from finance and molecular biology to geophysics and the Internet, the data are typically insufficient and the mechanistic insights are almost always too limited for the identification of power-law behavior to be scientifically useful (see the figure). Indeed, even most statistically “successful” calculations of power laws offer little more than anecdotal value.

Seeing colors in music, tasting flavors in shapes may happen in life's early months

2012-02-11T13:02:00.000+01:00

Triangles and circles placed atop

different background colors were

used as part of an experiment to

determine if infants might have

synesthesia.

Credit: Katie Wagner | UCSD

Famed violinist Itzhak Perlman sees a deep forest green whenever he plays a B-flat on his Stradivarius' G string. The A on the E string is red.

For Perlman, the connection between music and color is not a metaphor. When he plays an A, he sees red the same way the rest of us see white when we look at snow.

This trait is called synesthesia, and recent research suggests that all humans may have experienced it as infants. For adults, it involves a rare cross-wiring of the brain, so that stimulating one sensory or cognitive pathway automatically and involuntary stimulates another.

"It is not an add-on. Synesthetes experience two sensory stimuli at once," said Maureen Seaberg, a synesthete who wrote a book called "Tasting the Universe" on the subject.

Nor is synesthesia limited to music and colors. Researchers have identified more than 50 types. Seaberg, for example, has grapheme-color synesthesia, in which each letter of the alphabet has its own distinctive color. Others have ordinal-linguistic personification, where numbers and days of the week have distinct personalities.

Oscar-winning actress Tilda Swinton tastes words. The word "tomato" tastes lemony to her, while "table" evokes cake. According to Seaberg, word-tasters like Swinton “are the only ones who ever express any discomfort with synesthesia, since not every word tastes like cake.”

Seaberg remembers that as a child, she asked her mother why the letter A was always yellow. Her mother answered that she must have memorized it that way in class.

"That was a pretty good answer for the time, but what was more perplexing was why I saw the days of week and the months in color," Seaberg recounted.

She asked other adults and quickly realized it was better to remain quiet. "I spent the vast majority of my life keeping it a secret," Seaberg said.

Synesthesia has been known for thousands of years. The ancient Greeks speculated about it, and so did Isaac Newton. The first medical paper appeared 200 years ago, and it was widely studied over the next 100 years. The rise of behaviorism, which sought to make psychology more scientific by studying measurable behaviors rather than personal experiences, ended those investigations.

Then, in 1980, neurologist Richard Cytowic began studying synesthetes. He predicted that a stimulus that would ordinarily activate one sensory pathway in the brain would light up two areas in synesthetes. Brain imaging in the 1990s proved him right.

Seaberg discovered the name for her trait in a bookstore, when she noticed a very colorful copy of Cytowic's book, "The Man Who Tasted Shapes."

"When I started reading the inner flap, I finally had a name for what had been going on all my life," Seaberg said.

Although only 1-2 percent of the population experiences synesthesia, most researchers in the field believe all infants are synesthetes early in life.

Babies' neurons begin proliferating wildly as soon as they are born, forming many random connections, explained Karen Dobkins, a professor of psychology at University of California - San Diego.

Within a few months, as infants begin to recognize shapes, sounds, and tastes, they trim away the connections they no longer need. Researchers hypothesize that synesthetes retain some of those early connections.

This hypothesis is not easy to prove. "You can't ask babies directly if they are seeing colors when they look at shapes," Dobkins remarked. She and graduate student Katie Wagner developed an experiment to tease out the truth.

First, they created two identical images of black-lined triangles. They reasoned that if the infants truly experienced synesthesia, their minds would automatically color in the triangles, the way some adults color in letters.

They placed the two images side by side, one over a red background and the other over a green background. They showed the images to 15 two-month-olds and measured how long their eye stayed on each image. Then they tried the same experiment using circles instead of triangles.

"If the shape didn't matter, you would expect their eyes to spend the same amount of time on the red triangles as the red circles," Dobkins said. Instead, the amount of time varied by 12 to 14 percent, depending on what shape was on the color. The researchers believe the preference was due to the contrast between the background and the colors the infants' minds perceived inside the shapes.

The difference was greatest in two-month-olds. It faded in three-month-olds and disappeared in eight-month-olds and adults. While the experiment does not prove definitively that two-month-olds experience synesthesia, it offers tantalizing clues about how the brain develops and how this seemingly rare condition might be something we all experienced as infants.

Provided by Inside Science News Service (news : web)

What Does a Nebula Sound Like?

2012-02-11T12:53:00.003+01:00

What do things sound like out in the cosmos? Of course, sound waves can’t travel through the vacuum of space; however, electromagnetic waves can. These electromagnetic waves can be recorded by devices called spectrographs on many of the world’s most powerful telescopes. Astronomer Paul Francis from the Australian National University has used some of these recordings and converted them into sound by reducing their frequency 1.75 trillion times to make them audible, as the original frequencies are too high to be heard by the human ear.

“This allows us to listen to many parts of the universe for the first time,” Francis wrote on his website. “We can hear the song of a comet, the chimes of stars being born or dying, the choir of a quasar eating the heart of a galaxy, and much more.”

Above, is Francis’ recording of a nebula. It is actually a medley of sounds from different nebulae, but our friend César Cantú of the Chilidog Observatory in Monterrey, Mexico, has put together the sounds with images he took of the Rosette Nebula, or NGC2244.

This provides both a visual and audio hint of what a nebula might sound like, if our ears could hear at electromagnetic frequencies. Being able to ‘hear’ this gives one a feeling akin to being Superman! — as well as offering new insights into our Universe.

Francis also has the sounds of the Sun, quasars, comets, other nebulae, and more. Check outhis audio recordings here.

And many thanks to César Cantú to for sending us his video.

Is Venus’ Rotation Slowing Down?

2012-02-11T12:53:00.000+01:00

New measurements from ESA’s Venus Express spacecraft shows that Venus’ rotation rate is about 6.5 minutes slower than previous measurements taken 16 years ago by the Magellan spacecraft. Using infrared instruments to peer through the planet’s dense atmosphere, Venus Express found surface features weren’t where the scientists expected them to be.

“When the two maps did not align, I first thought there was a mistake in my calculations as Magellan measured the value very accurately, but we have checked every possible error we could think of,” said Nils Müller, a planetary scientist at the DLR German Aerospace Centre, lead author of a research paper investigating the rotation.

Venus Express in orbit since 2006 around our nearest planetary neighbor. Credits: ESA

Using the VIRTIS infrared instrument, scientists discovered that some surface features were displaced by up to 20 km from where they should be given the accepted rotation rate as measured by the Magellan orbiter in the early 1990s.

Over its four-year mission, Magellan determined the length of the day on Venus as being equal to 243.0185 Earth days. But the data from Venus Express indicate the length of the Venus day is on average 6.5 minutes longer.

What could cause the planet to slow down? One possibility may be the raging weather on Venus. Recent atmospheric models have shown that the planet could have weather cycles stretching over decades, which could lead to equally long-term changes in the rotation period. The most important of those forces is due to the dense atmosphere – more than 90 times the pressure of Earth’s and high-speed weather systems, which are believed to change the planet’s rotation rate through friction with the surface.

Earth experiences a similar effect, where it is largely caused by wind and tides. The length of an Earth day can change by roughly a millisecond and depends seasonally with wind patterns and temperatures over the course of a year.

But a change of 6.5 minutes over a little more than a decade is a huge variation.

Other effects could also be at work, including exchanges of angular momentum between Venus and the Earth when the two planets are relatively close to each other. But the scientists are still working to figure out the reason for the slow down.

These detailed measurements from orbit are also helping scientists determine whether Venus has a solid or liquid core, which will help our understanding how the planet formed and evolved. If Venus has a solid core, its mass must be more concentrated towards the center. In this case, the planet’s rotation would react less to external forces.

“An accurate value for Venus’ rotation rate will help in planning future missions, because precise information will be needed to select potential landing sites,” said Håkan Svedhem, ESA’s Venus Express project scientist.

Venus Express will keep monitoring the planet to determine if the rate of rotation continues to change.

Source: ESA

Vernissage de l'artiste peintre Vincent Ubags le 23/02/2012

2012-02-10T13:15:00.003+01:00

http://www.galerielasuperette.blogspot.com/

Researchers create 3-D laser maps that show how earthquake changes landscape

2012-02-09T21:14:00.000+01:00

This is a visualization of LiDAR data from the April, 2010 earthquake near Mexicali. Blue shows where ground surface moved down, red shows upward movement compared to the previous survey. Credit: Michael Oskin, UC Davis

Geologists have a new tool to study how earthquakes change the landscape down to a few inches, and it's giving them insight into how earthquake faults behave. In the Feb. 10 issue of the journal Science, a team of scientists from the U.S., Mexico and China reports the most comprehensive before-and-after picture yet of an earthquake zone, using data from the magnitude 7.2 event that struck near Mexicali, northern Mexico in April, 2010.

"We can learn so much about how earthquakes work by studying fresh fault ruptures," said Michael Oskin, geology professor at the University of California, Davis and lead author on the paper.

The team, working with the National Center for Airborne Laser Mapping (NCALM), flew over the area with LiDAR (light detection and ranging), which bounces a stream of laser pulses off the ground. New airborne LiDAR equipment can measure surface features to within a few inches. The researchers were able to make a detailed scan over about 140 square miles in less than three days, Oskin said.

Oskin said that they knew the area had been mapped with LiDAR in 2006 by the Mexican government. When the earthquake occurred, Oskin and Ramon Arrowsmith at Arizona State University applied for and got funding from the National Science Foundation to carry out an immediate aerial survey to compare the results.

Coauthors John Fletcher and graduate student Orlando Teran from the Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE) carried out a traditional ground survey of the fault rupture, which helped guide planning of the aerial LiDAR survey and the interpretation of the results.

From the ground, features like the five-foot escarpment created when part of a hillside abruptly moved up and sideways are readily visible. But the LiDAR survey further reveals warping of the ground surface adjacent to faults that previously could not easily be detected, Oskin said. For example, it revealed the folding above the Indiviso fault running beneath agricultural fields in the floodplain of the Colorado River.

"This would be very hard to see in the field," Oskin said.

Team members used the "virtual reality" facility at UC Davis's W. M. Keck Center for Active Visualization in Earth Sciences to handle and view the data from the survey. By comparing pre- and post-earthquake surveys, they could see exactly where the ground moved and by how much.

The survey revealed deformation around the system of small faults that caused the earthquake, and allowed measurements that provide clues to understanding how these multi-fault earthquakes occur.

The 2010 Mexicali earthquake did not occur on a major fault, like the San Andreas, but ran through a series of smaller faults in the Earth's crust. These minor faults are common around major faults but are "underappreciated," Oskin said.

"This sort of earthquake happens out of the blue," he said.

The new LiDAR survey shows how seven of these small faults came together to cause a major earthquake, Oskin said.

Ken Hudnut, a geophysicist with the U.S. Geological Survey and coauthor on the paper, made the first use of airborne LiDAR about 10 years ago to document surface faulting from the Hector Mine earthquake. But "pre-earthquake" data were lacking. Since then, NCALM has carried out LiDAR scans of the San Andreas system (the "B4 Project") and other active faults in the western U.S. (a component of the EarthScope Project), thereby setting a trap for future earthquakes, he said.

"In this case, fortunately, our CICESE colleagues had set such a trap, and this earthquake fell right into it and became the first ever to be imaged by "before" and "after'" LiDAR. It is a thrill for me to be on the team that reached this important milestone," Hudnut said.

More information: The post-event dataset collected by the team is publicly available through http://www.opentopography.org

Provided by University of California - Davis

Explained: Sigma

2012-02-09T21:09:00.001+01:00

On this chart of a 'normal' distribution, showing the classic 'bell curve' shape, the mean (or average) is the vertical line at the center, and the vertical lines to either side represent intervals of one, two and three sigma. The percentage of data points that would lie within each segment of that distribution are shown.

It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but also with judgments about what standards make sense in a given situation.

The unit of measurement usually given when talking about statistical significance is the standard deviation, expressed with the lowercase Greek letter sigma (σ). The term refers to the amount of variability in a given set of data: whether the data points are all clustered together, or very spread out.

In many situations, the results of an experiment follow what is called a “normal distribution.” For example, if you flip a coin 100 times and count how many times it comes up heads, the average result will be 50. But if you do this test 100 times, most of the results will be close to 50, but not exactly. You’ll get almost as many cases with 49, or 51. You’ll get quite a few 45s or 55s, but almost no 20s or 80s. If you plot your 100 tests on a graph, you’ll get a well-known shape called a bell curve that’s highest in the middle and tapers off on either side. That is a normal distribution.

The deviation is how far a given data point is from the average. In the coin example, a result of 47 has a deviation of three from the average (or “mean”) value of 50. The standard deviation is just the square root of the average of all the squared deviations. One standard deviation, or one sigma, plotted above or below the average value on that normal distribution curve, would define a region that includes 68 percent of all the data points. Two sigmas above or below would include about 95 percent of the data, and three sigmas would include 99.7 percent.

So, when is a particular data point — or research result — considered significant? The standard deviation can provide a yardstick: If a data point is a few standard deviations away from the model being tested, this is strong evidence that the data point is not consistent with that model. However, how to use this yardstick depends on the situation. John Tsitsiklis, the Clarence J. Lebel Professor of Electrical Engineering at MIT, who teaches the course Fundamentals of Probability, says, “Statistics is an art, with a lot of room for creativity and mistakes.” Part of the art comes down to deciding what measures make sense for a given setting.

For example, if you’re taking a poll on how people plan to vote in an election, the accepted convention is that two standard deviations above or below the average, which gives a 95 percent confidence level, is reasonable. That two-sigma interval is what pollsters mean when they state the “margin of sampling error,” such as 3 percent, in their findings.

That means if you asked an entire population a survey question and got a certain answer, and then asked the same question to a random group of 1,000 people, there is a 95 percent chance that the second group’s results would fall within two-sigma from the first result. If a poll found that 55 percent of the entire population favors candidate A, then 95 percent of the time, a second poll’s result would be somewhere between 52 and 58 percent.

Of course, that also means that 5 percent of the time, the result would be outside the two-sigma range. That much uncertainty is fine for an opinion poll, but maybe not for the result of a crucial experiment challenging scientists’ understanding of an important phenomenon — such as last fall’s announcement of a possible detection of neutrinos moving faster than the speed of light in an experiment at the European Center for Nuclear Research, known as CERN.

Six sigmas can still be wrong

Technically, the results of that experiment had a very high level of confidence: six sigma. In most cases, a five-sigma result is considered the gold standard for significance, corresponding to about a one-in-a-million chance that the findings are just a result of random variations; six sigma translates to one chance in a half-billion that the result is a random fluke. (A popular business-management strategy called “Six Sigma” derives from this term, and is based on instituting rigorous quality-control procedures to reduce waste.)

But in that CERN experiment, which had the potential to overturn a century’s worth of accepted physics that has been confirmed in thousands of different kinds of tests, that’s still not nearly good enough. For one thing, it assumes that the researchers have done the analysis correctly and haven’t overlooked some systematic source of error. And because the result was so unexpected and so revolutionary, that’s exactly what most physicists think happened — some undetected source of error.

Interestingly, a different set of results from the same CERN particle accelerator were interpreted quite differently.

A possible detection of something called a Higgs boson — a theorized subatomic particle that would help to explain why particles weigh something rather than nothing — was also announced last year. That result had only a 2.3sigma confidence level, corresponding to about one chance in 50 that the result was a random error (98 percent confidence level). Yet because it fits what is expected based on current physics, most physicists think the result is likely to be correct, despite its much lower statistical confidence level.

Significant but spurious

But it gets more complicated in other areas. “Where this business gets really tricky is in social science and medical science,” Tsitsiklis says. For example, a widely cited 2005 paper in the journal Public Library of Science — titled “Why most published research findings are wrong” — gave a detailed analysis of a variety of factors that could lead to unjustified conclusions. However, these are not accounted for in the typical statistical measures used, including “statistical significance.”

The paper points out that by looking at large datasets in enough different ways, it is easy to find examples that pass the usual criteria for statistical significance, even though they are really just random variations. Remember the example about a poll, where one time out of 20 a result will just randomly fall outside those “significance” boundaries? Well, even with a five-sigma significance level, if a computer scours through millions of possibilities, then some totally random patterns will be discovered that meet those criteria. When that happens, “you don’t publish the ones that don’t pass” the significance test, Tsitsiklis says, but some random correlations will give the appearance of being real findings — “so you end up just publishing the flukes.”

One example of that: Many published papers in the last decade have claimed significant correlations between certain kinds of behaviors or thought processes and brain images captured by magnetic resonance imaging, or MRI. But sometimes these tests can find apparent correlations that are just the results of natural fluctuations, or “noise,” in the system. One researcher in 2009 duplicated one such experiment, on the recognition of facial expressions, only instead of human subjects he scanned a dead fish — and found “significant” results.

“If you look in enough places, you can get a ‘dead fish’ result,” Tsitsiklis says. Conversely, in many cases a result with low statistical significance can nevertheless “tell you something is worth investigating,” he says.

So bear in mind, just because something meets an accepted definition of “significance,” that doesn’t necessarily make it significant. It all depends on the context.

Provided by Massachusetts Institute of Technology (news : web)

This story is republished courtesy of MIT News (http://web.mit.edu/newsoffice/), a popular site that covers news about MIT research, innovation and teaching.

Flipping a light switch in the cell: Quantum dots used for targeted neural activation Flipping a light switch in the cell: Quantum dots used for targeted neural activation

2012-02-09T13:20:00.000+01:00

Optically excited quantum dots in close proximity to a cell control the opening of ion channels. Credit: Lugo et al., University of Washington

By harnessing quantum dots—tiny light-emitting semiconductor particles a few billionths of a meter across—researchers at the University of Washington (UW) have developed a new and vastly more targeted way to stimulate neurons in the brain. Being able to switch neurons on and off and monitor how they communicate with one another is crucial for understanding—and, ultimately, treating—a host of brain disorders, including Parkinson's disease, Alzheimer's, and even psychiatric disorders such as severe depression. The research was published today in the Optical Society's (OSA) open-access journal Biomedical Optics Express.

Doctors and researchers today commonly use electrodes—on the scalp or implanted within the brain—to deliver zaps of electricity to stimulate cells. Unfortunately, these electrodes activate huge swaths of neural territory, made up of thousands or even millions of cells, of many different types. That makes it impossible to tease out the behavior of any given cell, or even of particular cell types, to understand cellular communication and how it contributes to the disease process.

Ideally, nerve cells would be activated in a non-invasive way that is also highly targeted. A promising method for doing this is photostimulation—essentially, controlling cells with light. Recently, for example, a team of Stanford University researchers altered mammalian nerve cells to carry light-sensitive proteins from single-celled algae, allowing the scientists to rapidly flip the cells on and off, just with flashes of light. The problem with this process, however, is that the light-controlled cells must be genetically altered to perform their parlor trick.

Optically excited quantum dots in close proximity to a cell control the opening of ion channels. Credit: Image adapted fromJiang et al., Chem. Mater., 2006, 18 (20), pp 4845-4854.

An alternative, says the UW team, led by electrical engineer Lih Y. Lin and biophysicist Fred Rieke, is to use quantum dots—tiny semiconductor particles, just a few billionths of a meter across, that confine electrons within three spatial dimensions. When these otherwise trapped electrons are excited by electricity, they emit light, but at very precise wavelengths, determined both by the size of the quantum dot and the material from which it is made. Because of this specificity, quantum dots are being explored for a variety of applications, including in lasers, optical displays, solar cells, light-emitting diodes, and even medical imaging devices.

In the paper published today, Lin, Rieke and colleagues have extended the use of quantum dots to the targeted activation of cells. In laboratory experiments, the researchers cultured cells on quantum dot films, so that the cell membranes were in close proximity to the quantum-dot coated surfaces. The electrical behavior of individual cells was then measured as the cells were exposed to flashes of light of various wavelengths; the light excited electrons within the quantum dots, generating electrical fields that triggered spiking in the cells.

"We tried prostate cancer cells first because a colleague happened to have the cell line and experience with them, and they are resilient, which is an advantage for culturing on the quantum dot films," Lin says. "But eventually we want to use this technology to study the behavior of neurons, so we switched to cortical neurons after the initial success with the cancer cells."

The experiments, says Lin, show that "it is possible to excite neurons and other cells and control their activities remotely using light. This non-invasive method can provide flexibility in probing and controlling cells at different locations while minimizing undesirable effects."

"Many brain disorders are caused by imbalanced neural activity," Rieke adds, and so "techniques that allow manipulation of the activity of specific types of neurons could permit restoration of normal—balanced—activity levels"—including the restoration of function in retinas that have been compromised by various diseases. "The technique we describe provides an alternative tool for exciting neurons in a spatially and temporally controllable manner. This could aid both in understanding the normal activity patterns in neural circuits, by introducing perturbations and monitoring their effect, and how such manipulations could restore normal circuit activity."

So far, the technique has only been applied to cells cultured outside the body; to gain insight into disease processes and be clinically useful, it would need to be performed within living tissue. To do so, Lin says, "we need to modify the surface of the quantum dots so that they can target specific cells when injected into live animals." The dots also need to be non-toxic, unlike those used in the Biomedical Optics Express report, which often had detrimental effects on the cells to which they were attached. "One solution would be developing non-toxic quantum dots using silicon," Lin says.

More information: "Remote switching of cellular activity and cell signaling using light in conjunction with quantum dots (http://www.opticsi … =boe-3-3-447)," Biomedical Optics Express, Vol. 3, Issue 3, pp. 447-454 (2012).

Provided by Optical Society of America (news : web)

Building mountains in a bottle

2012-02-09T13:15:00.001+01:00

The Landscape Evolution Observatory will enable scientists to better understand how water moves through different soil types and how changing climate conditions will impact the atmosphere and water resources in the future. Credit: Paul M. Ingram, Biosphere 2 science writer

(PhysOrg.com) -- Scientists are preparing to launch a 10-year project to study water resources, gas exchange and carbon cycling in three man-made landscapes built in a half-acre laboratory at the University of Arizona’s Biosphere 2.

Sunlight streams through the arched glass ceiling of an enclosure the size of an aircraft hanger, where 650 tons of crushed volcanic rocks from northern Arizona were unloaded last week through a 10-foot by 10-foot opening: Material to build the first of three mountains inside Biosphere 2.

"We think of them as three ships in a bottle," said Stephen DeLong, an assistant research professor at Biosphere 2 with a joint appointment in the UA's department of geosciences and lead scientist on the project.

It's the first and only experiment that will be able to reproduce the complex natural systems that control how water flows through the ground and how gases circulate in our atmosphere.

Funded by the Philecology Foundation, the Landscape Evolution Observatory, or LEO, will contain mountain slopes interlaced with a network of sensors that will allow the scientists to measure with greater precision than ever before everything from the speed with which water flows through the soil to exchange of gases through the leaves of plants.

Mountain or hill slopes are a vital part of the landscape, especially in the Desert Southwest, said DeLong. "Water and nutrients and plant life all occur on mountain slopes. They're especially important for humans because that's where water resources come from in the southwest – from the high elevation, mountain-sloped areas."

The idea for the project had its origins when the UA began managing Biosphere 2 in 2007. "There was a conscious decision to only take on the challenge of managing Biosphere 2 if scientists here at the UA could figure out a really neat, really new project," said DeLong. "A new use for the facility that really couldn't be done anywhere else in the world."

"Right now we can make observations of the natural world, which are obviously very important, but the natural world is very complicated," he added. "We're building this intermediate scale in the biosphere. These hills approach a natural scale, and they have some of the complexities of a natural system.

"This is also an opportunity to get lots of different scientists together to tackle things like how climate change will affect ecology and water availability in the future and how we might be able to improve the models and theory for how water moves through landscapes and how carbon and energy and all these very complicated systems work together."

The measurements the researchers record at LEO will bridge the gap between small-scale controlled experiments and observational studies of hydrology, atmospheric cycling and climate change on a global scale.

The researchers will embed sensors in the soil to measure temperature, water flow and soil chemistry. “One of the most exciting things about the project is that we will really understand the soil hydrology and the soil chemistry and how this physical system behaves for a year or two, and then we’ll add plants to it so that we can see how the plants feedback with the hydrology and with the soil chemistry,” said Stephen DeLong, an assistant professor at Biosphere 2 and lead scientist on the LEO project. Credit: Paul M. Ingram, Biosphere 2 science writer

"In a laboratory you can really control an experiment and understand everything that goes in and out, but it doesn't really tell you much about how big systems interact," said DeLong. "Here we can see how big systems interact."

Currently under construction, LEO is expected to be operational by the end of 2012. "We're building three identical slopes," said DeLong. "First we'll run them as replicates, and then perhaps we can diverge them and run them at different climates or with different plants."

All of the materials for building the steel framework, the sensors and the slopes themselves have to be carried through the 10-foot by 10-foot opening.

"We're putting the soil on now and next we will build a crane system that allows the researchers to access different points without disturbing the surface," said DeLong. "We've designed a rain system that can simulate everything from a light winter rain to a fairly heavy monsoon storm."

Ability to control temperature and rain will allow the scientists to study how climate change will impact atmospheric chemistry, water resources and plant and microbial life in the soil.

"We're going to start out with a very homogenous, even soil material," said DeLong. "Crushed volcanic rock, material that erupted out of a volcano in northern Arizona about 100,000 years ago. It's very young, like yesterday to a geologist."

The scientists decided to use volcanic rock because of its unique chemical composition: The minerals that make up the rocks are relatively unstable and will weather and change during the lifetime of the experiment. "In the 10 years or so of the experiment, we'll see these volcanic minerals turned into things like clays and that will affect how water moves through the soil, so we'll see realistic hydrology," said DeLong. "That allows us to see how soil evolves in real time."

A network of about 1,800 sensors and samplers arrayed through each slope will take measurements of the amount of water in the soil at a particular point, the soil chemistry and temperature, the types of gases released from the soil and other parameters. "It's a relatively controlled environment within the facility where we can make a lot of measurements of trace gases, carbon dioxide and oxygen levels," said DeLong.

The researchers will be able to draw gas and water out from the soil through a network of samplers connected to the structure. "We'll be able to see what's going on chemically and biologically and we won't have to dig into the soil and disturb it," said DeLong. "We can just pump the gas and the water out and run analyses on them."

According to DeLong, "Once we introduce plants to the environment, water will be transpired through the plants, they're going to put organic material into the soil and encourage a lot of biologic activity and things are really going to change."

DeLong stressed the advantage of running different climate scenarios," said DeLong. "We can really understand the hydrology well, understand how water moves through with different rain scenarios, understand how the plants feedback, and then run a big drought. And then we can run a second drought that's somewhat warmer and start to see how these changes really affect the landscape."

The data from LEO will help to improve regional and global climate models by providing the researchers with real evidence of how the changing climate will affect movement of water, ecology and how the atmosphere interacts with the soil.

"We know that here in the southwest there's a massive die-off of pine trees," said DeLong. "We don't fully understand it but we understand that it's related to drought, to climate change and to invasive species. We can get at this in our model system and really understand the different controls on some of these phenomena."

Through a two-story glass wall at Biosphere 2, visitors can view the construction of LEO, and at the end of 2012 they will be able to see the model mountainsides. "Visitors also get a chance to talk to me and other researchers and technicians in an informal way, which is a nice way for the public to learn more about how science is done," said DeLong.

Like the global climate and landscape interactions that it reflects, LEO is an evolving and ever-changing study. "We're always open to new ideas. Getting new scientists and new students involved over the years will really guide the project," said DeLong. "There are going to be a lot of opportunities scientifically."

Provided by University of Arizona (news : web)

My connectome, myself

2012-02-08T00:17:00.002+01:00

The cover of Connectome. Image: Houghton Mifflin Harcourt

The human brain has 100 billion neurons, each of which is connected to many others. Neuroscientists believe these connections hold the key to our memories, personality and even mental disorders such as schizophrenia. By unraveling them, we may be able to learn more about how we become our unique selves, and possibly even how to alter those selves.

Mapping all those connections may sound like a daunting task, but MIT neuroscientist Sebastian Seung believes it can be done — one cubic millimeter of brain tissue at a time.

“When you start to explain how difficult it would be to find the connectome of an entire brain, people ask, ‘What’s the point? That seems too far off.’ But even finding or mapping the connections in a small piece of brain can tell you a lot,” says Seung, a professor of computational neuroscience and physics at MIT.

Even more than our genome, our connectome shapes who we are, says Seung, who outlines his vision for connectome research in a new book, Connectome, published this month by Houghton Mifflin Harcourt. “Clearly genes are very important, but because they don’t change after the moment of conception, they can’t really account for the effects of experience,” he says.

A streambed of consciousness

Seung envisions the brain’s connections as the “streambed” through which our consciousness flows. At a molecular level, that streambed consists of billions of synapses, in which one neuron sends signals to the next via chemical neurotransmitters. While scientists once believed that synapses could not be changed after formation, they now know that synapses are continuously strengthening, weakening, disappearing and reforming, as we learn new things and have new experiences.

While neuroscientists have long hypothesized that the key to our unique selves lies in those connections, this has proven impossible to test because the technology to map the connections did not exist. That is now changing, due to the efforts of Seung and a handful of other neuroscientists around the world.

At the Max Planck Institute for Medical Research in Heidelberg, Germany, neuroscientists in the laboratory of Winfried Denk have taken extremely thin slices of brain tissue and generated electron-microscope images of all the neural connections within each slice. However, the next step — mapping those connections — is extremely time-consuming. Seung estimates that it would take 100,000 years for a lone worker to trace the connections in one cubic millimeter of brain tissue.

To help speed that up, Seung and his colleagues have developed an artificial intelligence (AI) system, which they presented at the International Conference on Computer Vision and the Neural Information Processing Systems Conference in 2009. However, the system still requires human guidance, so the researchers are enlisting the help of the general public through a website called eyewire.org. “The brain is like a vast jungle of neurons,” Seung says. “They’re like trees that are all tangled up together, and people can help us explore that.”

Participants in the Eyewire project will help guide the computer program when it loses track of where a neuronal extension goes amidst the tangle of neurons.

“The person can click the mouse and say color here, and the computer starts coloring again, and keeps going, and then stops again when it’s uncertain. So you’re guiding the computer,” Seung says. Furthermore, the AI system becomes “smarter” as people guide it, so it will need less and less help as it goes on.

Rather than tackling the human brain right away, the researchers are beginning with a 300- by 350- by 80-micron slice of mouse retinal tissue. Images of just this small piece of tissue take up a terabyte of data, or enough to hold 220 million pages of text.

In a review published in New Scientist, Terrence Sejnowski, the Francis Crick Professor of Computational Neurobiology at the Salk Institute, says the book “gives a sense of the excitement on the cutting edge of neuroscience.” Sejnowski points out that connectomics, just like genomics, will be aided by the rapid advance of technology. “Once a certain threshold has been achieved, something that seemed impossible becomes possible, and soon becomes routine,” he writes.

Miswired brains

While everyone’s connectomes are different, extreme differences may account for mental disorders such as autism and schizophrenia. Neuroscientists have long speculated that autism and schizophrenia are caused by problems in brain wiring, but haven’t been able to test that theory. Once a typical human connectome has been mapped, scientists will be able to compare it to the wiring diagrams of small chunks of the brains of mice engineered to express autism or schizophrenia symptoms, in the hopes of figuring out why those disorders arise and, potentially, how to treat them.

“Finding those differences, of course, is not a cure or treatment, it’s just a starting point. But I would argue that being able to see those differences would be a huge step forward,” Seung says. “Imagine studying infectious diseases before there were microscopes. You could see the symptoms, but you couldn’t see the microbes. That’s why, for a long time, people didn’t believe schizophrenia had a biological basis, because they looked at the brain and there was nothing obviously wrong.”

In the last section of Connectome, Seung addresses some futuristic applications of connectomics, drawn directly from science fiction — ideas such as uploading human brains into computers or freezing bodies to preserve them until technology is developed to bring them back to life.

“My goal in those chapters is to point out that we can start to examine those dreams in a critical way,” Seung says. For example, he suggests that cryogenics is only a feasible plan if it can be shown that the connectome survives the freezing and thawing intact. “My point in those chapters is to introduce a dose of science into science fiction.”

Provided by Massachusetts Institute of Technology (news : web)

This story is republished courtesy of MIT News (http://web.mit.edu/newsoffice/), a popular site that covers news about MIT research, innovation and teaching.

Entire genome of extinct human decoded from fossil

2012-02-08T00:11:00.001+01:00

Researchers have now been able to sequence the entire Denisova genome using 10 milligram of a finger bone fragment that was found in the Denisova-Cave in Southern Sibiria. © MPI for Evolutionary Anthropology

(PhysOrg.com) -- In 2010, Svante Pääbo and his colleagues presented a draft version of the genome from a small fragment of a human finger bone discovered in Denisova Cave in southern Siberia. The DNA sequences showed that this individual came from a previously unknown group of extinct humans that have become known as Denisovans. Together with their sister group the Neandertals, Denisovans are the closest extinct relatives of currently living humans.

The Leipzig team has now developed sensitive novel techniques which have allowed them to sequence every position in the Denisovan genome about 30 times over, using DNA extracted from less than 10 milligrams of the finger bone. In the previous draft version published in 2010, each position in the genome was determined, on average, only twice. This level of resolution was sufficient to establish the relationship of Denisovans to Neandertals and present-day humans, but often made it impossible for researchers to study the evolution of specific parts of the genome. The now-completed version of the genome allows even the small differences between the copies of genes that this individual inherited from its mother and father to be distinguished. This Wednesday the Leipzig group makes the entire Denisovan genome sequence available for the scientific community over the internet.

“The genome is of very high quality”, says Matthias Meyer, who developed the techniques that made this technical feat possible. “We cover all non-repetitive DNA sequences in the Denisovan genome so many times that it has fewer errors than most genomes from present-day humans that have been determined to date”.

The genome represents the first high-coverage, complete genome sequence of an archaic human group - a leap in the study of extinct forms of humans. “We hope that biologists will be able to use this genome to discover genetic changes that were important for the development of modern human culture and technology, and enabled modern humans to leave Africa and rapidly spread around the world, starting around 100,000 years ago” says Pääbo. The genome is also expected to reveal new aspects of the history of Denisovans and Neandertals.

The group plans to present a paper describing the genome later this year. “But we want to make it freely available to everybody already now” says Pääbo. “We believe that many scientists will find it useful in their research”.

The project is made possible by financing from the Max Planck Society and is part of efforts since almost 30 years by Dr. Pääbo’s group to study ancient DNA. The finger bone was discovered by Professor Anatoly Derevianko and Professor Michail Shunkov from the Russian Academy of Sciences in 2008 during their excavations at Denisova Cave, a unique archaeological site which contains cultural layers indicating that human occupation at the site started up to 280,000 years ago. The finger bone was found in a layer which has been dated to between 50,000 and 30,000 years ago.

The genome is available at http://www.eva.mpg.de/denisova and as a Public Data Set via Amazon Web Services (AWS):http://aws.amazon.com/datasets/2357 .

Provided by Max-Planck-Gesellschaft (news : web)

A bronze matryoshka doll: The metal in the metal in the metal

2012-02-07T20:14:00.000+01:00

Just like in the Russian wooden toy, a hull of 12 copper atoms encases a single tin atom. This hull is, in turn, enveloped by 20 further tin atoms. With their large surfaces these structures can serve as highly efficient catalysts. Credit: TUM

A doll in a doll, and then one more, enveloping them from the outside – this is how Thomas Faessler explains his molecule. He packs one atom in a cage within an atom framework. With their large surfaces these structures can serve as highly efficient catalysts. Just like in the Russian wooden toy, a hull of twelve copper atoms encases a single tin atom. This hull is, in turn, enveloped by 20 further tin atoms. Professor Faessler's work group at the Institute of Inorganic Chemistry at the Technische Universitaet Muenchen (Germany) was the first to generate these spatial structures built up in three layers as isolated metal clusters in bronze alloys.

Particularly fascinating are the images the researchers use to explain these chemical compounds and their properties. In the laboratory the substance is an unimpressive, fine, grayish-black powder, yet the structure models are in color and in various nested shapes. These powders, with their large surfaces, are interesting as an interim step for catalysts that transfer hydrogen, for instance. Similar structures made of silicon could be used in solar cells to capture light from the sun more effectively.

Most people view metals as uniform materials with a rather unspectacular structure. The metal compounds from Faessler's institute are quite the opposite. His desk is piled high with various multicolored cage models with yellow spheres representing copper atoms and blue ones for tin. The analogy to the carbon spheres that caused a sensation as Buckyballs can not be overlooked. Here, too, there are geometric structures made up of triangles, pentagons and hexagons. However, they are not made of carbon: heavier metals such as tin and lead can also form such isolated cage structures.

A string of tin atoms is surrounded by a layer of copper atoms, and around that yet another tube of tin atoms. Such fibers could one day be used as molecular wires with various electrical properties. Credit: Andrea Hoffmann / TUM

"We are basically interested in alloy structures that are out of the ordinary," says Faessler. Bronze, for example: this mixture of copper and tin, which was discovered early on and lent its name to an entire age of humanity, has a crystalline structure; the atoms of the two components are distributed evenly throughout the entire crystal and are densely packed together.

The new bronzes from the Faessler laboratory are different. The PhD candidate Saskia Stegmaier melted a particularly pure form of copper wire and tin granulate under special conditions – protected from air and moisture in an argon atmosphere. The bronze produced in this manner was then sealed into an alkali metal such as potassium in an ampoule made of tantalum. The melting point of tantalum is 3,000 degrees Celsius, making it particularly well suited as a vessel for binging other metals into contact with each other.

This is how the new metal clusters, nested inside each other just like the Russian doll, came into existence. When bronze is heated, together with potassium or sodium, to 600 to 800 degrees Celsius, the alkali metals act like scissors that cut up the alloy grid and then edge their way between the pieces, thereby stabilizing the isolated atomic clusters. On their own, these clusters cannot organize themselves into dense, uniformly structured layers to form crystals. They are made up of pentagons with 20 tin atoms in all – a constellation in which repetitive patterns are not possible under normal conditions. But "cheating" a little and using potassium atoms as glue can produce a seemingly normal crystal. Last year the Israeli scientist Dan Shechtman received the Nobel Prize for chemistry for the discovery of a similar phenomenon – the so-called quasi-crystals with five-fold symmetry.

"Our clusters are small units. They are, so to speak, piles of atoms that are not connected to their neighbors." That makes them ideal for catalytic applications: "Because they are consistent in size," explains Faessler, "they are much better at steering chemical reactions than classical catalysts." Hydration reactions in which hydrogen atoms dock to organic molecule chains with oxygen atoms, e.g. in the synthesis of artificial flavors, are examples of such processes. Typically, expensive precious metals like rhodium are used for this. However, novel polar alloys with magnesium, cobalt and tin can serve the same purpose. "What we need for an efficient reaction is a catalyst with very large surface area." The classical method of achieving this is to mix solutions of two metal salts to precipitate extremely small nanoparticles. "This results in an entire spectrum of particle sizes," explains Faessler. With metal clusters we can tailor the catalyst to our needs, as it were."

However, Stegmaier's and Faessler's reaction vessel contained more surprises. Aside from the clusters, the scientists noticed a fiber-like material – like thin needles – whose ends could be bent a little. "We suspected," says Stegmaier, "this could turn out to be exiting." In the meantime the yield of the fibers has been improved by using sodium as scissors to cut up the bronze. This time the result was not spheres, but multilayered rods. In the middle is a string of tin atoms, surrounded by a layer of copper atoms, and around that yet another tube of tin atoms. Just as the hollow Matryoshka molecules are reminiscent of Buckyballs, the new fibers with their tubes are akin to carbonnanotubes. Analogously, such fibers could one day be used as molecular wires with various electrical properties.

More information: S. Stegmaier, T. F. Faessler, A Bronze Matryoshka – The Discrete Intermetalloid Cluster [Sn@Cu12@Sn20]12– in the Ternary Phases A12Cu12Sn21 (A = Na, K) J. Am. Chem. Soc. 2011, 133, 19758-19768. DOI:10.1021/ja205934p

S. Stegmaier, T. F. Faessler, Na2.8Cu5Sn5.6 – A Crystalline Alloy Featuring Intermetalloid 1∞{Sn0.6@Cu5@Sn5} Double-Wall Nano Rods with Five-Fold Symmetry , Angew. Chem, Early View Online, 1 February 2012,DOI:10.1002/anie.201107985

Provided by Technische Universitaet Muenchen

It's not solitaire: Brain activity differs when one plays against others

2012-02-07T14:12:00.000+01:00

Rock, paper or scissors? Learning while playing a strategic game against others involves a different pattern of brain activity than learning from the consequences of one's own actions, researchers found. Credit: L. Brian Stauffer

Researchers have found a way to study how our brains assess the behavior – and likely future actions – of others during competitive social interactions. Their study, described in a paper in the Proceedings of the National Academy of Sciences, is the first to use a computational approach to tease out differing patterns of brain activity during these interactions, the researchers report.

"When players compete against each other in a game, they try to make a mental model of the other person's intentions, what they're going to do and how they're going to play, so they can play strategically against them," said University of Illinois postdoctoral researcher Kyle Mathewson, who conducted the study as a doctoral student in the Beckman Institute with graduate student Lusha Zhu and economics professor and Beckman affiliate Ming Hsu, who now is at the University of California, Berkeley. "We were interested in how this process happens in the brain."

Previous studies have tended to consider only how one learns from the consequences of one's own actions, called reinforcement learning, Mathewson said. These studies have found heightened activity in the basal ganglia, a set of brain structures known to be involved in the control of muscle movements, goals and learning. Many of these structures signal via the neurotransmitter dopamine.

"That's been pretty well studied and it's been figured out that dopamine seems to carry the signal for learning about the outcome of our own actions," Mathewson said. "But how we learn from the actions of other people wasn't very well characterized."

Researchers call this type of learning "belief learning."

To better understand how the brain processes information in a competitive setting, the researchers used functional magnetic resonance imaging (fMRI) to track activity in the brains of participants while they played a competitive game, called a Patent Race, against other players. The goal of the game was to invest more than one's opponent in each round to win a prize (a patent worth considerably more than the amount wagered), while minimizing one's own losses (the amount wagered in each trial was lost). The fMRI tracked activity at the moment the player learned the outcome of the trial and how much his or her opponent had wagered.

A computational model evaluated the players' strategies and the outcomes of the trials to map the brain regions involved in each type of learning.

"Both types of learning were tracked by activity in the ventral striatum, which is part of the basal ganglia," Mathewson said. "That's traditionally known to be involved in reinforcement learning, so we were a little bit surprised to see that belief learning also was represented in that area."

Belief learning also spurred activity in the rostral anterior cingulate, a structure deep in the front of the brain. This region is known to be involved in error processing, regret and "learning with a more social and emotional flavor," Mathewson said.

The findings offer new insight into the workings of the brain as it is engaged in strategic thinking, Hsu said, and may aid the understanding of neuropsychiatric illnesses that undermine those processes.

"There are a number of mental disorders that affect the brain circuits implicated in our study," Hsu said. "These include schizophrenia, depression and Parkinson's disease. They all affect these dopaminergic regions in the frontal and striatal brain areas. So to the degree that we can better understand these ubiquitous social functions in strategic settings, it may help us understand how to characterize and, eventually, treat the social deficits that are symptoms of these diseases."

Provided by University of Illinois at Urbana-Champaign (news : web)

Optics get magnetic powers

2012-02-04T01:04:00.000+01:00

Figure 1: Dichroic glass used in jewelry produces different colors from light beams that travel along different paths. Similarly, rare-earth perovskite materials with dynamic cross-coupling between magnetic and electric fields have optical properties that depend on the direction of light. Credit: 2012 iStockphoto/JodiJacobson

For decades, scientists have studied a class of materials called ‘multiferroics’ in which static electric and magnetic structures are coupled to each other. This allows capabilities such as controlling magnetic order with electric fields instead of magnetic ones, making it easier to build devices such as sensors and computer memory.

The dynamic equivalent of this static coupling, or the linking of the electric and magnetic fields of excitations inside materials, would expand these capabilities even further. However, observations of dynamic coupling have been rare and coupling strengths weak. Now, researchers in Japan have observed strong cross-coupling of dynamic excitations in multiferroic materials called rare-earth perovskites. The work has revealed optical properties in opto-electronic materials similar to those found in common dichroic glass (Fig.1), and may make possible new types of optical devices.

Control via coupling

At the microscopic level, the electric and magnetic field structures inside any material are complicated. Small displacements of electrons from their equilibrium positions cause electric polarization and create associated electric fields. Similarly, electrons have either a ‘spin up’ or ‘spin down’ magnetic configuration that can produce magnetic fields, or dipoles. These electric and magnetic fields can be aligned randomly, or they can form complex, large-area structures useful for devices, explains Youtarou Takahashi from the Japan Science and Technology Agency and the RIKEN Advanced Science Institute, who led the team that observed the dynamic cross-coupling.

The microscopic electric fields in ‘ferroelectric’ materials, for example, are organized into domains containing millions of atoms. The fields inside a single domain point in the same direction, which can be set with an externally applied electric field. Since information can be stored in the domain orientations, scientists are studying ferroelectrics as candidates for next-generation, ultra-high-density storage. Similarly, microscopic domains in ferromagnets align into domains that can be controlled with an external magnet.

Figure 2: A schematic diagram of directional dichroism behavior. A rare-earth perovskite (black blocks) absorbs light (purple arrows). The internal magnetic (M) and electric (P) fields of the perovskite interact with the light according to their orientation relative to the light. As a result, the strength with which the perovskite absorbs light depends on the light’s direction. Absorption strengths are equal for configurations connected by a '='. Credit: Ref. 1 © 2012 Y. Takahashi et al.

In most devices made from ferroelectric and ferromagnetic materials, like controls like: electric fields control electric domains, and magnetic fields control magnetic domains. In multiferroics, however, electric fields control magnetic structures and vice versa. This is useful because magnetic fields are more difficult to create and control at small scales than electric fields. The ability to move beyond static cross-coupling, and link the electric and magnetic field components of a time-varying excitation, could yield additional capabilities, such as control over the absorption of light and its direction.

Getting excited

Takahashi, along with colleagues from the University of Tokyo and the RIKEN Advanced Science Institute, observed strong, dynamic coupling by studying how rare-earth perovskite materials absorb light at terahertz frequencies. The microscopic magnetic field components, called spins, in these materials arrange spontaneously into a helix. Because light consists of oscillating electric and magnetic fields, its absorption can distort the material’s atomic lattice.

Other researchers had previously observed that light absorption in rare-earth perovskites established a transient electric field that distorted the magnetic spin helix structure by modulating the interactions between neighboring spins. However, the reverse coupling did not exist—the magnetic distortion, or excitation, did not affect electric polarization—so the excitation was not mutually cross-coupled, Takahashi notes.

Takahashi and colleagues extended these results by changing the orientation of the incident light relative to the perovskite atomic lattice. They exploited the fact that rare-earth perovskites have an inherent electric field, or polarization, which results from a combination of their helical spin structure, and a ‘spin–orbit’ interaction that couples the orbital motion of electrons to electron spin. They found that, when they oriented the electric field of the incident light perpendicularly to the material’s inherent electric field, a truly cross-coupled excitation resulted.

This cross-coupling resulted from the fact that the perovskite’s inherent electric field was derived entirely from its helical spin structure: when it was affected by the light field, the spin structure was affected. And when the spin structure distorted, it in turn changed the electric field. The researchers confirmed the cross-coupled nature of the excitation by studying how absorption strength changed under different magnetic fields and varying incident light energy.

Switching backwards and forwards

Takahashi and his colleagues also demonstrated an immediate and remarkable consequence of this cross-coupled excitation: their rare-earth perovskite absorbed more of the light that passed through it in one direction than it did light passing through in the opposite direction. In a regular material, the absorption strength would be identical in each direction since only the strength of the electric polarization, internal to the material—not its direction—would affect absorption. When cross-coupling occurs, however, the directions of the absorbing material’s internal electric and magnetic fields also matter. Because reversing the direction of light travel reverses at least one of these internal field directions, absorption will vary for different directions of travel (Fig. 2).

This so-called ‘directional dichroism’ effect, reminiscent of dichroic glass, could have applications to efficient optical switching of terahertz light signals in high-speed communication switches and optical circuits. This and other applications may represent the beginning of a new field. “I think that this research marks the beginning of magneto-electric optics, which will be based on a firm understanding of the microscopic mechanisms in magneto-electric materials,” says Takahashi.

This nascent field will be helped, Takahashi continues, by the likelihood that cross-coupled excitations will turn out to be relatively common. Like the excitations observed here, they will probably be in the gigahertz-to-terahertz frequency regime, and will occur in materials that exhibit ferroelectric order derived from magnetic spin structure—possibly including many of the multiferroics that are already known to scientists.

More information: Takahashi, Y., et al. Magnetoelectric resonance with electromagnons in a perovskite helimagnet. Nature Physics published online, 4 December 2011 doi: 10.1038/NPHYS2161 .

Provided by RIKEN (news : web)

A Tour Of Detroit's Ghetto

2012-02-01T19:13:00.002+01:00

How do you fight fire in space? Experiments provide some answers

2012-01-31T20:57:00.001+01:00

This is a color image of a burning droplet during a fuel combustion experiment on the International Space Station. Credit: NASA/Glenn Research Center

Improving fire-fighting techniques in space and getting a better understanding of fuel combustion here on Earth are the focus of a series of experiments on the International Space Station, led by a professor at the Jacobs School of Engineering at the University of California, San Diego. A first round of experiments ran from March 2009 to December 2011. A second round kicked off in January and is set to last a year or more.

Forman Williams, a professor of mechanical and aerospace engineering, has been working on fire research and fire safety with NASA since the 1970s. You will not, however, find him on the space station. The experiments are run by remote control from NASA's John Glenn Research Center in Cleveland. Williams and colleagues at Princeton, UC Davis, the University of Connecticut and Cornell analyze the results at their home institutions. They will present findings based on the first series of experiments this summer at a symposium in Poland.

"Research leads to a better understanding of fire behavior," Willams said. "And better understanding ultimately leads to better safety designs."

All the experiments take place in a chamber located in the Destiny module of the International Space Station. The chamber is part of a piece of equipment called the Combustion Integrated Rack, which is roughly the size of a 5.5-foot bookcase and weighs close to 560 lbs. The rack is crammed with sensors and equipped with video cameras that record experiments. The chamber is equipped with a device called the Multiuser Droplet Combustion Apparatus that can generate and ignite droplets from different fuels in different atmospheric conditions.

The Combustion Integrated Rack is used on the International Space station to conduct fuel combustion experiments. Credit: NASA/Glenn Research Center

Fire safety on the space station

The Flame Extinguishment Experiment, known as FLEX, ran in the chamber from March 2009 to December 2011. The goal was to get a better understanding of how fire happens on a space craft, where there is no up or down and where atmosphere and pressure are tightly controlled. The ultimate goal was to improve fire-fighting techniques in space.

To help understand how flames behave and burn in space, FLEX researchers ignited a small drop of either heptane or methanol. As this little sphere of fuel burned for about 20 seconds, it was engulfed by a spherically symmetric flame. The droplet shrank until either the flame extinguished or the fuel ran out.

Flames in space can burn at a lower temperature, at a lower rate and with less oxygen than in normal gravity. This means that materials used to extinguish fire must be present in higher concentrations. The slow flow of air from the fans mixing air in a spacecraft can make flames burn even faster.

The space station is equipped with carbon-dioxide fire extinguishers, so researchers investigated how fuel droplets burn in the presence of different amounts of CO2. Also, ambient air can become completely fire safe when there is not enough oxygen for fuels to ignite. This threshold is called the limiting oxygen index. Williams and colleagues pinpointed this index for methanol and heptane on the space station.

Astronaut Mike Fincke pictured to the left of the Combustion Integrated Rack facility installed in the Destiny module of the ISS shortly after installation. Credit: NASA

Fuel combustion experiments

Williams is now working on a new series of experiments, called FLEX-2, which aims to recreate conditions that are closer to what actually happens in a combustion engine. Findings could lead to new designs for cleaner fuels that have a smaller carbon footprint and emit fewer pollutants, among other applications.

While the original FLEX experiments looked at fuels with only one component, FLEX-2 will run tests on fuels with two components, more similar to fuels used in real-life conditions, which usually have multiple components. While FLEX examined the behavior of single fuel droplets, the new round of tests will also look at the interaction of two fuel droplets.

But Williams said he isn't quite done with the original FLEX experiments. He and colleagues still need to explain some of what they observed. For example, when the flame around a fuel droplet extinguishes, that droplet should stop shrinking because combustion has essentially stopped. But in about a dozen instances during the FLEX experiments, heptane droplets kept shrinking at the same rate as when the flame was still burning. Williams, who has studied combustion for the past 50 years, said he has never seen anything like it.

Tests on the space shuttle

This is not Williams' first round of tests to be run in space. His work includes several experiments that ran on Spacelab, a science module flown in the cargo bay of U.S. space shuttles. The holy grail of combustion science is a flame around a fuel droplet that looks like a perfectly symmetrical sphere. That is very hard to achieve here on Earth. It is however a common occurrence in microgravity. Spherical symmetry makes it easier to observe droplets' behavior and to craft the calculations that explain it, Williams said.

During the space shuttle missions, he and colleagues used to work around the clock at the Marshall Space Flight Center in Huntsville, Ala. Williams and colleagues also took their families to Cape Canaveral to watch space shuttle Columbia take off in July 1997, when it was carrying a microgravity combustion experiment they designed.

William's interest in combustion dates back to his undergraduate days at Princeton. He was taking a graduate-level course. His professor wrote out on the blackboard the conservation equations of combustion. "When I realized how complicated they were, I said to myself that there is enough there to last me a lifetime," Williams explained.

Provided by University of California - San Diego (news : web)

Students discover millisecond pulsar, help in the search for gravitational waves

2012-01-31T20:49:00.000+01:00

Using an array of millisecond pulsars, astronomers can detect tiny changes in the pulse arrival times in order to detect the influence of gravitational waves. Credit: NRAO

A special project to search for pulsars has bagged the first student discovery of a millisecond pulsar – a super-fast spinning star, and this one rotates about 324 times per second. The Pulsar Search Collaboratory (PSC) has students analyzing real data from the National Radio Astronomy Observatory’s (NRAO) Robert C. Byrd Green Bank Telescope (GBT) to find pulsars. Astronomers involved with the project said the discovery could help detect elusive ripples in spacetime known as gravitational waves.

“Gravitational waves are ripples in the fabric of spacetime predicted by Einstein’s theory of General Relativity,” said Dr. Maura McLaughlin, from West Virginia University. “We have very good proof for their existence but, despite Einstein’s prediction back in the early 1900s, they have never been detected.”

Four other pulsars have been discovered by high school students participating in this project.

“When you discover a pulsar, you feel like you’re walking on air! It is the best experience you can ever have,” said student co-discoverer Jessica Pal of Rowan County High School in Kentucky. “You get to meet astronomers and talk to them about your experience. I still can’t believe I found a pulsar. It is wonderful to know that there is something out there in space that you discovered.”

The other student involved in the discovery was Emily Phan of George C. Marshall High School in Virginia, who along with Pal found the millisecond pulsar on January 17, 2012. It was later confirmed by Max Sterling of Langley High School, Sydney Dydiw of Trinity High School, and Anne Agee of Roanoke Valley Governor’s School, all in Virginia.

“I am considering pursuing astronomy as a career choice,” said Agee. “The Pulsar Search Collaboratory has opened my eyes to how fun astronomy can be!”

Once the pulsar candidate was reported to NRAO, a followup observing session was scheduled on the giant, 17-million-pound telescope. On January 24, 2012, observations confirmed that the pulsar was real.

Pulsars are spinning neutron stars that sling “lighthouse beams” of radio waves around as they rotate. A neutron star is what is left after a massive star explodes at the end of its “normal” life. With no nuclear fuel left to produce energy to offset the stellar remnant’s weight, its material is compressed to extreme densities. The pressure squeezes together most of its protons and electrons to form neutrons; hence, the name “neutron star.” One tablespoon of material from a pulsar would weigh 10 million tons.

The object that the students discovered is a special class of pulsars called millisecond pulsars, which are the fastest-spinning neutron stars. They are highly stable and keep time more accurately than atomic clocks.

On January 24, 2012, observations with the Green Bank Telescope at 800 MHz confirmed that the signal was astronomical and zeroed in on its position. Pulsars are brighter at lower frequencies (like 350 MHz, above) than at higher frequencies, and so the confirmation plot is noisier than the original data. Since this pulsar spins so fast, it may be used as part of the pulsar timing array used to detect gravitational waves. Courtesy NRAO.

Astronomers don’t know much about them, however. But because of their stability, these pulsars may someday allow astronomers to detect gravitational waves.

Millisecond pulsars, however, could hold the key to that discovery. Like buoys bobbing on the ocean, pulsars can be perturbed by gravitational waves.

“Gravitational waves are invisible,” said McLaughlin. “But by timing pulsars distributed across the sky, we may be able to detect very small changes in pulse arrival times due to the influence of these waves.”

Millisecond pulsars are generally older pulsars that have been “spun up” by stealing mass from companion stars, but much is left to discover about their formation.

“This latest discovery will help us understand the genesis of millisecond pulsars,” said Dr. Duncan Lorimer, who is also part of the project. “It’s a very exciting time to be finding pulsars!”

The PSC is a joint project of the National Radio Astronomy Observatory and West Virginia University, funded by a grant from the National Science Foundation. The PSC includes training for teachers and student leaders, and provides parcels of data from the GBT to student teams. The project involves teachers and students in helping astronomers analyze data from the GBT.

Approximately 300 hours of the observing data were reserved for analysis by student teams. These students have been working with about 500 otherstudents across the country. The responsibility for the work, and for the discoveries, is theirs. They are trained by astronomers and by their teachers to distinguish between pulsars and noise.

The PSC will continue through the 2012-2013 school year. Teachers interested in participating in the program can learn more at this link. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

Source: Universe Today

Moonlighting enzyme works double shift 24/7

2012-01-31T20:47:00.000+01:00

MSU researchers found a moonlighting enzyme

in Arabidopsis that works double shifts 24/7.

Credit: Photo illustration by G.L. Kohuth

A team of researchers led by Michigan State University has discovered an overachieving plant enzyme that works both the day and night shifts.

The discovery, featured in the current issue of Proceedings of the National Academy of Sciences, shows that plants evolved a new function for this enzyme by changing merely one of its protein building blocks.

The enzyme, ATP synthase, usually works the day shift, serving as a key player in storing energy created through photosynthesis in the chloroplast. When the sun goes down most of these enzymes switch off to prevent energy from leaking out.

The newly changed protein building block, or subunit, allows this enzyme to do another job once the sun goes down and photosynthesis stops, said David Kramer, Hannah Distinguished Professor of Photosynthesis and Bioenergetics.

"By exchanging this one building block, the enzyme gains a new function in the dark, in the roots." he said. "It's like a food processor. With one attachment it chops food. Swap it for another, and it kneads bread dough."

The building block on which the researchers focused is called gamma, a component of ATP synthase. There are two forms of gamma, gamma-1 and gamma-2. When researchers removed gamma-1, photosynthesis was completely stopped. When gamma-2 was removed, the plant could not make normal root hairs (the part of the root that takes up nutrients.) On the other end of the spectrum, plants engineered to produce lots of gamma-2 made very long root hairs.

So, the seemingly small change not only allows the enzyme to pick up an additional shift, but to also work a completely different job – from storing energy during the day to transporting energy in the roots at night.

This particular enzyme also functions as a regulator of photosynthesis, controlling how much energy plants consume. Too much light causes damage while too little results in low energy, which keeps the plants from growing to their full potential.

Kramer's next phase of research in this realm will investigate regulating the enzyme's effect on increasing photosynthesis, which could potentially lead to more efficient plants and algae.

Kramer works in the MSU-Department of Energy Plant Research Laboratory. The research team included scientists from Washington State University, Ludwig Maximilians University (Germany), Albert Ludwigs University (Germany) and the Centre de la Recherche Scientifique (France).

Provided by Michigan State University (news : web)

Learning-based tourism an opportunity for industry expansion

2012-01-30T23:41:00.000+01:00

A guide on Sparks Lake in the Oregon Cascade Range explains the geologic history and ecology of the area to tourists, in the shadow of the South Sister volcano. (Photo courtesy of Oregon State University)

New research suggests that major growth in the travel, leisure and tourism industry in the coming century may be possible as more people begin to define recreation as a learning and educational opportunity – a way to explore new ideas and cultures, art, science and history.

Some of this is already happening, although the expansion of tourism in much of the 20th century was often focused on amusement parks and tropical resorts – not that there's anything wrong with them.

But in a recent study published in the Annals of Tourism Research, experts say that increasingly affluent and educated people around the world are ready to see travel in less conventional ways, and that lifelong learning and personal enrichment can compete favorably with sandy beaches or thrill rides.

"The idea of travel as a learning experience isn't new, it's been around a long time," said John Falk, a professor of science education at Oregon State University and international leader in the "free-choice learning" movement, which taps into personal interests to help boost intellectual growth beyond what's taught in schools and through formal education.

In the 1700s and 1800s, a "Grand Tour" of Europe was considered an educational rite of passage for upper-class citizens of the gentry or nobility, in which months of travel throughout the continent offered education about art, culture, language, everything from history to science, fencing and dancing.

There may not be as much demand today to perfect one's skills with a sword, but the concept is the same.

"For a long time the travel industry has been focused on hedonistic escapism," Falk said. "That's okay, but as more and more people have the time, means and opportunity to travel, a lot of them are ready to go beyond that. There are many other interesting things to do, and people are voting with their feet.

"You're already seeing many tour operators and travel agencies offer educational opportunities, things like whale watching, ecotourism," Falk said. "The National Park Service does a great job with its resources, teaching people about science, geology and history. The push for more international travel experiences as a part of formal education for students is an outgrowth of this concept.

"We're convinced this is just the beginning of a major shift in how people want to spend their leisure time, and one that could have important implications for intellectual and cultural growth around the world," he said.

Among the observations the researchers make in their study:

More leisure time and lower relative cost of travel near the end of the 20th century has opened the door for people to consider different types of recreation focused on intellectual engagement.
A growing appetite for lifelong learning is being underserved by the existing tourism industry.
A major expansion of learning-based tourism will require both participants and the tourism industry to overcome a long-standing bias that recreation and education are opposite ends of the spectrum – to accept that learning can be fun.
The cultural impact of "being there" makes for a memorable learning experience of great personal value to participants, and is often just the beginning of a continued interest in a topic.
People seek experiences that are sensation-rich, alter their view of the world, or instill a sense of wonder, beauty and appreciation.
A down side to travel and learning can occur if tourists use the experience to reinforce colonialist, racial or cultural stereotypes.
Tourism activities are most successful if the participant feels active and engaged, rather than just receiving a recitation of facts to correct a "knowledge deficit."

Collaborators on this research were from the University of Queensland in Australia.

"It is expected that tourism will become ever more centered upon a quest for something larger, something more personally fulfilling," the researchers wrote in their report. "It is argued that the quest for knowledge and understanding, enacted through travel, will continue to be a dominant theme of the new century."

Provided by Oregon State University (news : web)

Europe's Orbiting Observatories Capture Stunning New Images of the "Pillars of Creation"

2012-01-28T21:25:00.001+01:00

Two of the European Space Agency's (ESA) orbiting observatories have captured new and spectacular views of the gas pillars in the Eagle Nebula (M16) that were the subject of the iconic 1995 Hubble images dubbed "Pillars of Creation."

In 1995, the Hubble Space Telescope's 'Pillars of Creation' image of the Eagle Nebula became one of the most iconic images of the 20th century. Now, two of ESA's orbiting observatories --Stunning new Herschel and XMM-Newton-- have revealed new insights this enigmatic star-forming region.

The pillars are only a small portion of the extensive nebulous region imaged in far-infrared by ESA’s Herschel Space Observatory, which shows cool dust and gas tendrils being carved away by the hot stars seen in the X-ray image from XMM-Newton. The wide-field optical image from the ESO MPG telescope puts the pillars into context against the full scale of the nebula, which is over 75 light-years across.

The Eagle Nebula is 6500 light-years away in the constellation of Serpens. It contains a young hot star cluster, NGC6611, visible with modest back-garden telescopes, that is sculpting and illuminating the surrounding gas and dust, resulting in a huge hollowed-out cavity and pillars, each several light-years long.

The Hubble image hinted at new stars being born within the pillars, deeply inside small clumps known as 'evaporating gaseous globules' or EGGs. Owing to obscuring dust, Hubble's visible light picture was unable to see inside and prove that young stars were indeed forming. The ESA Herschel Space Observatory's new image shows the pillars and the wide field of gas and dust around them. Captured in far-infrared wavelengths, the image allows astronomers to see inside the pillars and structures in the region.

In parallel, a new multi-energy X-ray image from ESA's XMM-Newton telescope shows those hot young stars responsible for carving the pillars. Combining the new space data with near-infrared images from the European Southern Observatory's (ESO's) Very Large Telescope at Paranal, Chile, and visible-light data from its Max Planck Gesellschaft 2.2m diameter telescope at La Silla, Chile, we see this iconic region of the sky in a uniquely beautiful and revealing way.

In visible wavelengths, the nebula shines mainly due to reflected starlight and hot gas filling the giant cavity, covering the surfaces of the pillars and other dusty structures.Multi wavelength video of the Eagle Nebula.

At near-infrared wavelengths, the dust becomes almost transparent and the pillars practically vanish. In far-infrared, Herschel detects this cold dust and the pillars reappear, this time glowing in their own light.
The 8.2m-diameter VLT’s ANTU telescope imaged the famous Pillars of Creation region and its surroundings in near-infrared using the ISAAC instrument. This enabled astronomers to penetrate the obscuring dust in their search to detect newly formed stars.

The research into the ‘evaporating gaseous globules’ (EGGs), which were first detected in the Hubble images, needed the near-infrared capabilities and resolution of the VLT to peel back the layers of dust and detect the low-mass young stars cocooned within the EGG shells. The near-infrared results showed that 11 of the 73 EGGs detected possibly contained stars, and that the tips of the pillars contain stars and nebulosity not seen in the Hubble image.

Intricate tendrils of dust and gas are seen to shine, giving astronomers clues about how it interacts with strong ultraviolet light from the hot stars seen by XMM-Newton.

In 2001, Very Large Telescope near-infrared images had shown only a small minority of the EGGs were likely to contain stars being born.

However, Herschel's image makes it possible to search for young stars over a much wider region and thus come to a much fuller understanding of the creative and destructive forces inside the Eagle Nebula. Earlier mid-infrared images from ESA's Infrared Space Observatory and NASA's Spitzer, and the new XMM-Newton data, have led astronomers to suspect that one of the massive, hot stars in NGC6611 may have exploded in a supernova 6000 years ago, emitting a shockwave that destroyed the pillars. However, because of the distance of the Eagle Nebula, we won't see this happen for several hundred years yet. Powerful ground-based telescopes continue to provide astonishing views of our Universe, but images in far-infrared, mid-infrared and X-ray wavelengths are impossible to obtain owing to the absorbing effects of Earth's atmosphere.

Space-based observatories such as ESA's Herschel and XMM-Newton help to peel back that veil and see the full beauty of the Universe across the electromagnetic spectrum.

XMM-Newton’s images of the Eagle Nebula region in X-rays, above is colour-coded to show different energy levels (red: 0.3–1 keV, green: 1–2 keV and blue: 2–8 keV) is helping astronomers to investigate a theory that the Eagle Nebula is being powered by a hidden supernova remnant. The researchers are looking for signs of very diffuse emission and how far this extends around the region. They believe that an absence of this X-ray emission beyond that found by previous orbiting space telescopes (Chandra and Spitzer) would support the supernova remnant theory.

With regions like the Eagle Nebula, combining all of these observations helps astronomers to understand the complex yet amazing lifecycle of stars.

The Daily Galaxy via European Space Agency

Blind moles use beauty for function, not fancy

2012-01-28T13:13:00.000+01:00

Golden mole. Image: Wikipedia.

(PhysOrg.com) -- Scientists have long wondered why a blind mole that lives in underground darkness has beautiful iridescent hair. After all, many animals or birds with magnificent features exhibit their colorful beauty for mating purposes. Now, a new study shows that the iridescent hairs of the blind golden mole, Chrysochloridae, aren’t for attracting potential mates. Instead, the shiny coats help the rodents function efficiently underground.

Colorful iridescent hues ranging from green to purple result from light reflecting off of the moles’ flat hair. The smooth hair — discovered by UA biology honors alumna Holly Snyder, along with integrated bioscience Ph.D. student Rafael Maia, postdoctoral fellow

Liliana D’Alba and associate professor of biology Matthew Shawkey — helps the moles maneuver easily through dirt and sand.

“These moles are blind and live underground and, consequently, don’t use the colors to communicate with one another as they would typically do by way of color,” Shawkey says. Shawkey and his research colleagues discovered that the moles’ hair cuticles, arranged in multiple layers of thin material, bend light and create a spectrum of colors.

Using microspectrophotometry, electron microcopy and optical modeling, the researchers also found the moles’ hair is flat like a pancake, increasing the amount of surface area and light reflected.

“The color just might be an incidental byproduct,” Shawkey says. “These moles have evolved structures that have two distinct properties: color and wear-resistance. This could give usinspiration for developing new multifunctional materials. Who knows, maybe ahair-care company could apply these findings to make human hair iridescent!”

Findings of the research team, which also includes Allison Schultz, San Diego State University; and Karen Rowe and Kevin Rowe, Museum of Vertebrate Zoology, University of California, Berkeley, and Museum Victoria, Melbourne, Victoria, Australia, are published in the Jan. 25, 2012 issue of the Royal Society journal Biology Letters at http://rsbl.royals … 11.1168.full .

Provided by University of Akron