Sunday, June 23, 2013

Sun Emits a Solstice CME

This image from June 20, 2013, at 11:15 p.m. EDT shows the bright light of a solar flare on the left side of the sun and an eruption of solar material shooting through the sun’s atmosphere, called a prominence eruption. Shortly thereafter, this same region of the sun sent a coronal mass ejection out into space. (Credit: Credit: NASA/SDO)


June 23, 2013 — On June 20, 2013, at 11:24 p.m., the sun erupted with an Earth-directed coronal mass ejection or CME, a solar phenomenon that can send billions of tons of particles into space that can reach Earth one to three days later. These particles cannot travel through the atmosphere to harm humans on Earth, but they can affect electronic systems in satellites and on the ground.

Experimental NASA research models, based on observations from NASA's Solar Terrestrial Relations Observatory and ESA/NASA's Solar and Heliospheric Observatory show that the CME left the sun at speeds of around 1350 miles per second, which is a fast speed for CMEs.
Earth-directed CMEs can cause a space weather phenomenon called a geomagnetic storm, which occurs when they funnel energy into Earth's magnetic envelope, the magnetosphere, for an extended period of time. The CME's magnetic fields peel back the outermost layers of Earth's fields changing their very shape. Magnetic storms can degrade communication signals and cause unexpected electrical surges in power grids. They also can cause aurora. Storms are rare during solar minimum, but as the sun's activity ramps up every 11 years toward solar maximum -- currently expected in late 2013 -- large storms occur several times per year.
In the past, geomagnetic storms caused by CMEs of this strength and direction have usually been mild.
In addition, the CME may pass by additional spacecraft: Messenger, STEREO B, Spitzer, and their mission operators have been notified. If warranted, operators can put spacecraft into safe mode to protect the instruments from the solar material.


Story Source:
The above story is reprinted from materials provided byNASA/Goddard Space Flight Center.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Sunday, June 16, 2013

Mystery of X-Ray Light from Black Holes Solved



June 14, 2013 — It is a mystery that has stymied astrophysicists for decades: how do black holes produce so many high-power X-rays?

In a new study, astrophysicists from The Johns Hopkins University, NASA and the Rochester Institute of Technology conducted research that bridges the gap between theory and observation by demonstrating that gas spiraling toward a black hole inevitably results in X-ray emissions.
The paper states that as gas spirals toward a black hole through a formation called an accretion disk, it heats up to roughly 10 million degrees Celsius. The temperature in the main body of the disk is roughly 2,000 times hotter than the sun and emits low-energy or "soft" X-rays. However, observations also detect "hard" X-rays which produce up to 100 times higher energy levels.
Julian Krolik, professor of physics and astronomy in the Zanvyl Krieger School of Arts and Sciences, and his fellow scientists used a combination of supercomputer simulations and traditional hand-written calculations to uncover their findings. Supported by 40 years of theoretical progress, the team showed for the first time that high-energy light emission is not only possible, but is an inevitable outcome of gas being drawn into a black hole.
"Black holes are truly exotic, with extraordinarily high temperatures, incredibly rapid motions and gravity exhibiting the full weirdness of general relativity," Krolik said. "But our calculations show we can understand a lot about them using only standard physics principles."
The team's work was recently published in the print edition ofAstrophysical Journal. His collaborators on the study include Jeremy Schnittman, a research astrophysicist from the NASA Goddard Space Flight Center, and Scott Noble, an associate research scientist from the Center for Computational Relativity and Gravitation at RIT. Schnittman was lead author.
As the quality and quantity of the high-energy light observations improved over the years, evidence mounted showing that photons must be created in a hot, tenuous region called the corona. This corona, boiling violently above the comparatively cool disk, is similar to the corona surrounding the sun, which is responsible for much of the ultra-violet and X-ray luminosity seen in the solar spectrum.
While the team's study of black holes and high-energy light confirms a widely-held belief, the role of advancing modern technology should not be overlooked. A grant from the National Science Foundation enabled the team to access Ranger, a supercomputing system at the Texas Advanced Computing Center located at the University of Texas in Austin. Ranger worked over the course of about 27 days, over 600 hours, to solve the equations.
Noble developed the computer simulation solving all of the equations governing the complex motion of inflowing gas and its associated magnetic fields near an accreting black hole. The rising temperature, density and speed of the inflowing gas dramatically amplify magnetic fields threading through the disk, which then exert additional influence on the gas.
The result is a turbulent froth orbiting the black hole at speeds approaching the speed of light. The calculations simultaneously tracked the fluid, electrical and magnetic properties of the gas while also taking into account Einstein's theory of relativity.
"In some ways, we had to wait for technology to catch up with us," Krolik said. "It's the numerical simulations going on at this level of quality and resolution that make the results credible."
The scientists are all familiar with each other as their paths have all crossed with Krolik during graduate school at Johns Hopkins. Schnittman was previously a postdoctoral fellow mentored by Krolik from 2007 to 2010 while Noble was an assistant research scientist and instructor also under Krolik from 2006 to 2009.
The work was supported by the National Science Foundation Grants AST-0507455, AST- 0908336 and AST-1028087.

Story Source:
The above story is reprinted from materials provided by Johns Hopkins University.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. Jeremy D. Schnittman, Julian H. Krolik, Scott C. Noble. X-RAY SPECTRA FROM MAGNETOHYDRODYNAMIC SIMULATIONS OF ACCRETING BLACK HOLESThe Astrophysical Journal, 2013; 769 (2): 156 DOI: 10.1088/0004-637X/769/2/156

Thursday, June 13, 2013

How Diving Mammals Evolved Underwater Endurance

How did seals and sea lions and other aquatic mammals evolve the ability to survive for long periods underwater without breathing? (Credit: © Rafael Ben-Ari / Fotolia)


June 13, 2013 — Scientists at the University of Liverpool have shed new light on how diving mammals, such as the sperm whale, have evolved to survive for long periods underwater without breathing.

The team identified a distinctive molecular signature of the oxygen-binding protein myoglobin in the sperm whale and other diving mammals, which allowed them to trace the evolution of the muscle oxygen stores in more than 100 mammalian species, including their fossil ancestors.
Myoglobin, which gives meat its red colour, is present in high concentrations in elite mammalian divers, so high that the muscle is almost black in colour. Until now, however, very little was known about how this molecule is adapted in champion divers.
Proteins tend to stick together at high concentrations, impairing their function, so it was unclear how myoglobin was able to help the body store enough oxygen to allow mammals, such as whales and seals, to endure underwater for long periods of time without breathing. Elite mammalian divers can hold their breath for over an hour while they hunt in the depths of the oceans, while land mammals, such as humans, can hold their breath for only a few minutes.
Dr Michael Berenbrink, from the University's Institute of Integrative Biology, who led the international team, explains: "We studied the electrical charge on the surface of myoglobin and found that it increased in mammals that can dive underwater for long periods of time. We were surprised when we saw the same molecular signature in whales and seals, but also in semi-aquatic beavers, muskrats and even water shrews.
"By mapping this molecular signature onto the family tree of mammals, we were able to reconstruct the muscle oxygen stores in extinct ancestors of today's diving mammals. We were even able to report the first evidence of a common amphibious ancestor of modern sea cows, hyraxes and elephants that lived in shallow African waters some 65 million years ago."
Dr Scott Mirceta, PhD student on the project, added: "Our study suggests that the increased electrical charge of myoglobin in mammals that have high concentrations of this protein causes electro-repulsion, like similar poles of two magnets. This should prevent the proteins from sticking together and allow much higher concentrations of the oxygen-storing myoglobin in the muscles of these divers."
"We are really excited by this new find, because it allows us to align the anatomical changes that occurred during the land-to-water transitions of mammals with their actual physiological diving capacity. This is important for understanding the prey items that were available to these extinct animals and their overall importance for past aquatic ecosystems."
The research, funded by the Biotechnology and Biological Sciences Research Council (BBSRC), could also help improve understanding of a number of human diseases where protein aggregation is a problem, such as Alzheimer's and diabetes, and could inform the development of artificial blood substitutes.
Dr Berenbrink added: "This finding illustrates the strength of combining molecular, physiological and evolutionary approaches to biological problems and, for the first time, allows us to put 'flesh' onto the bones of these long extinct divers."

Story Source:
The above story is reprinted from materials provided byUniversity of Liverpool.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. S. Mirceta, A. V. Signore, J. M. Burns, A. R. Cossins, K. L. Campbell, M. Berenbrink. Evolution of Mammalian Diving Capacity Traced by Myoglobin Net Surface Charge.Science, 2013; 340 (6138): 1234192 DOI:10.1126/science.1234192

Wednesday, June 12, 2013

Discovery of New Material State Counterintuitive to Laws of Physics

It’s like squeezing a stone and forming a giant sponge,” said Argonne chemist Karena Chapman. “Materials are supposed to become denser and more compact under pressure. We are seeing the exact opposite." (Credit: Image courtesy of DOE/Argonne National Laboratory)


June 12, 2013 — When you squeeze something, it gets smaller. Unless you're at Argonne National Laboratory.

At the suburban Chicago laboratory, a group of scientists has seemingly defied the laws of physics and found a way to apply pressure to make a material expand instead of compress/contract.
"It's like squeezing a stone and forming a giant sponge," said Karena Chapman, a chemist at the U.S. Department of Energy laboratory. "Materials are supposed to become denser and more compact under pressure. We are seeing the exact opposite. The pressure-treated material has half the density of the original state. This is counterintuitive to the laws of physics."
Because this behavior seems impossible, Chapman and her colleagues spent several years testing and retesting the material until they believed the unbelievable and understood how the impossible could be possible. For every experiment, they got the same mind-bending results.
"The bonds in the material completely rearrange," Chapman said. "This just blows my mind."
This discovery will do more than rewrite the science text books; it could double the variety of porous framework materials available for manufacturing, health care and environmental sustainability.
Scientists use these framework materials, which have sponge-like holes in their structure, to trap, store and filter materials. The shape of the sponge-like holes makes them selectable for specific molecules, allowing their use as water filters, chemical sensors and compressible storage for carbon dioxide sequestration of hydrogen fuel cells. By tailoring release rates, scientists can adapt these frameworks to deliver drugs and initiate chemical reactions for the production of everything from plastics to foods.
"This could not only open up new materials to being porous, but it could also give us access to new structures for selectability and new release rates," said Peter Chupas, an Argonne chemist who helped discover the new materials.
The team published the details of their work in the May 22 issue of the Journal of the American Chemical Society in an article titled "Exploiting High Pressures to Generate Porosity, Polymorphism, And Lattice Expansion in the Nonporous Molecular Framework Zn(CN)2 ."
The scientists put zinc cyanide, a material used in electroplating, in a diamond-anvil cell at the Advanced Photon Source (APS) at Argonne and applied high pressures of 0.9 to 1.8 gigapascals, or about 9,000 to 18,000 times the pressure of the atmosphere at sea level. This high pressure is within the range affordably reproducible by industry for bulk storage systems. By using different fluids around the material as it was squeezed, the scientists were able to create five new phases of material, two of which retained their new porous ability at normal pressure. The type of fluid used determined the shape of the sponge-like pores. This is the first time that hydrostatic pressure has been able to make dense materials with interpenetrated atomic frameworks into novel porous materials. Several series of in situ high-pressure X-ray powder diffraction experiments were performed at the 1-BM, 11-ID-B, and 17-BM beamlines of the APS to study the material transitions.
"By applying pressure, we were able to transform a normally dense, nonporous material into a range of new porous materials that can hold twice as much stuff," Chapman said. "This counterintuitive discovery will likely double the amount of available porous framework materials, which will greatly expand their use in pharmaceutical delivery, sequestration, material separation and catalysis."
The scientists will continue to test the new technique on other materials.
The research is funded by the U.S. Department of Energy's Office of Science.

Story Source:
The above story is reprinted from materials provided byDOE/Argonne National Laboratory.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. Saul H. Lapidus, Gregory J. Halder, Peter J. Chupas, Karena W. Chapman. Exploiting High Pressures to Generate Porosity, Polymorphism, And Lattice Expansion in the Nonporous Molecular Framework Zn(CN)2Journal of the American Chemical Society, 2013; 135 (20): 7621 DOI: 10.1021/ja4012707

Tuesday, June 11, 2013

Scientists Discover New Layer of the Human Cornea

Scientists have discovered a previously undetected layer in the cornea, the clear window at the front of the human eye. (Credit: © Kesu / Fotolia)



June 11, 2013 — Scientists at The University of Nottingham have discovered a previously undetected layer in the cornea, the clear window at the front of the human eye.

The breakthrough, announced in a study published in the academic journal Ophthalmology, could help surgeons to dramatically improve outcomes for patients undergoing corneal grafts and transplants.
The new layer has been dubbed the Dua's Layer after the academic Professor Harminder Dua who discovered it.
Professor Dua, Professor of Ophthalmology and Visual Sciences, said: "This is a major discovery that will mean that ophthalmology textbooks will literally need to be re-written. Having identified this new and distinct layer deep in the tissue of the cornea, we can now exploit its presence to make operations much safer and simpler for patients.
"From a clinical perspective, there are many diseases that affect the back of the cornea which clinicians across the world are already beginning to relate to the presence, absence or tear in this layer."
The human cornea is the clear protective lens on the front of the eye through which light enters the eye. Scientists previously believed the cornea to be composed of five layers, from front to back, the corneal epithelium, Bowman's layer, the corneal stroma, Descemet's membrane and the corneal endothelium.
The new layer that has been discovered is located at the back of the cornea between the corneal stroma and Descemet's membrane. Although it is just 15 microns thick -- the entire cornea is around 550 microns thick or 0.5mm -- it is incredibly tough and is strong enough to be able to withstand one and a half to two bars of pressure.
The scientists proved the existence of the layer by simulating human corneal transplants and grafts on eyes donated for research purposes to eye banks located in Bristol and Manchester.
During this surgery, tiny bubbles of air were injected into the cornea to gently separate the different layers. The scientists then subjected the separated layers to electron microscopy, allowing them to study them at many thousand times their actual size.
Understanding the properties and location of the new Dua's layer could help surgeons to better identify where in the cornea these bubbles are occurring and take appropriate measures during the operation. If they are able to inject a bubble next to the Dua's layer, its strength means that it is less prone to tearing, meaning a better outcome for the patient.
The discovery will have an impact on advancing understanding of a number of diseases of the cornea, including acute hydrops, Descematocele and pre-Descemet's dystrophies.
The scientists now believe that corneal hydrops, a bulging of the cornea caused by fluid build up that occurs in patients with keratoconus (conical deformity of the cornea), is caused by a tear in the Dua layer, through which water from inside the eye rushes in and causes waterlogging.

Story Source:
The above story is reprinted from materials provided byUniversity of Nottingham, via AlphaGalileo.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. Harminder S. Dua, Lana A. Faraj, Dalia G. Said, Trevor Gray, James Lowe. Human Corneal Anatomy RedefinedOphthalmology, 2013; DOI:10.1016/j.ophtha.2013.01.018

Marks On Martian Dunes May Be Tracks of Dry-Ice Sleds

Several types of downhill flow features have been observed on Mars. This image from the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter is an example of a type called "linear gullies." (Credit: NASA/JPL-Caltech/Univ. of Arizona)



June 11, 2013 — NASA research indicates hunks of frozen carbon dioxide -- dry ice -- may glide down some Martian sand dunes on cushions of gas similar to miniature hovercraft, plowing furrows as they go.

Researchers deduced this process could explain one enigmatic class of gullies seen on Martian sand dunes by examining images from NASA's Mars Reconnaissance Orbiter (MRO) and performing experiments on sand dunes in Utah and California.
"I have always dreamed of going to Mars," said Serina Diniega, a planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and lead author of a report published online by the journal Icarus. "Now I dream of snowboarding down a Martian sand dune on a block of dry ice."
The hillside grooves on Mars, called linear gullies, show relatively constant width -- up to a few yards, or meters, across -- with raised banks or levees along the sides. Unlike gullies caused by water flows on Earth and possibly on Mars, they do not have aprons of debris at the downhill end of the gully. Instead, many have pits at the downhill end.
"In debris flows, you have water carrying sediment downhill, and the material eroded from the top is carried to the bottom and deposited as a fan-shaped apron," said Diniega. "In the linear gullies, you're not transporting material. You're carving out a groove, pushing material to the sides."
Images from MRO's High Resolution Imaging Science Experiment (HiRISE) camera show sand dunes with linear gullies covered by carbon-dioxide frost during the Martian winter. The location of the linear gullies is on dunes that spend the Martian winter covered by carbon-dioxide frost. By comparing before-and-after images from different seasons, researchers determined that the grooves are formed during early spring. Some images have even caught bright objects in the gullies.
Scientists theorize the bright objects are pieces of dry ice that have broken away from points higher on the slope. According to the new hypothesis, the pits could result from the blocks of dry ice completely sublimating away into carbon-dioxide gas after they have stopped traveling.
"Linear gullies don't look like gullies on Earth or other gullies on Mars, and this process wouldn't happen on Earth," said Diniega. "You don't get blocks of dry ice on Earth unless you go buy them."
That is exactly what report co-author Candice Hansen, of the Planetary Science Institute in Tucson, Ariz., did. Hansen has studied other effects of seasonal carbon-dioxide ice on Mars, such as spider-shaped features that result from explosive release of carbon-dioxide gas trapped beneath a sheet of dry ice as the underside of the sheet thaws in spring. She suspected a role for dry ice in forming linear gullies, so she bought some slabs of dry ice at a supermarket and slid them down sand dunes.
That day and in several later experiments, gaseous carbon dioxide from the thawing ice maintained a lubricating layer under the slab and also pushed sand aside into small levees as the slabs glided down even low-angle slopes.
The outdoor tests did not simulate Martian temperature and pressure, but calculations indicate the dry ice would act similarly in early Martian spring where the linear gullies form. Although water ice, too, can sublimate directly to gas under some Martian conditions, it would stay frozen at the temperatures at which these gullies form, the researchers calculate.
"MRO is showing that Mars is a very active planet," Hansen said. "Some of the processes we see on Mars are like processes on Earth, but this one is in the category of uniquely Martian."
Hansen also noted the process could be unique to the linear gullies described on Martian sand dunes.
"There are a variety of different types of features on Mars that sometimes get lumped together as 'gullies,' but they are formed by different processes," she said. "Just because this dry-ice hypothesis looks like a good explanation for one type doesn't mean it applies to others."
The University of Arizona Lunar and Planetary Laboratory operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp. of Boulder, Colo. JPL, a division of the California Institute of Technology in Pasadena, manages MRO for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems, Denver, built the orbiter.
To see images of the linear gullies and obtain more information about MRO, visit: http://www.nasa.gov/mro .
For more about HiRISE, visit: http://hirise.lpl.arizona.edu .


Story Source:
The above story is reprinted from materials provided byNASA/Jet Propulsion Laboratory.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. S. Diniega, C.J. Hansen, J.N. McElwaine, C.H. Hugenholtz, C.M. Dundas, A.S. McEwen, M.C. Bourke. A new dry hypothesis for the formation of martian linear gullies.Icarus, 2013; 225 (1): 526 DOI:10.1016/j.icarus.2013.04.006

Video Gamers Really Do See More: Gamers Capture More Information Faster for Visual Decision-Making

New research shows that playing video games trains the brain to make better and faster use of visual input. (Credit: © tomispin / Fotolia)



June 11, 2013 — Hours spent at the video gaming console not only train a player's hands to work the buttons on the controller, they probably also train the brain to make better and faster use of visual input, according to Duke University researchers.

"Gamers see the world differently," said Greg Appelbaum, an assistant professor of psychiatry in the Duke School of Medicine. "They are able to extract more information from a visual scene."
It can be difficult to find non-gamers among college students these days, but from among a pool of subjects participating in a much larger study in Stephen Mitroff's Visual Cognition Lab at Duke, the researchers found 125 participants who were either non-gamers or very intensive gamers.
Each participant was run though a visual sensory memory task that flashed a circular arrangement of eight letters for just one-tenth of a second. After a delay ranging from 13 milliseconds to 2.5 seconds, an arrow appeared, pointing to one spot on the circle where a letter had been. Participants were asked to identify which letter had been in that spot.
At every time interval, intensive players of action video games outperformed non-gamers in recalling the letter.
Earlier research by others has found that gamers are quicker at responding to visual stimuli and can track more items than non-gamers. When playing a game, especially one of the "first-person shooters," a gamer makes "probabilistic inferences" about what he's seeing -- good guy or bad guy, moving left or moving right -- as rapidly as he can.
Appelbaum said that with time and experience, the gamer apparently gets better at doing this. "They need less information to arrive at a probabilistic conclusion, and they do it faster."
Both groups experienced a rapid decay in memory of what the letters had been, but the gamers outperformed the non-gamers at every time interval.
The visual system sifts information out from what the eyes are seeing, and data that isn't used decays quite rapidly, Appelbaum said. Gamers discard the unused stuff just about as fast as everyone else, but they appear to be starting with more information to begin with.
The researchers examined three possible reasons for the gamers' apparently superior ability to make probabilistic inferences. Either they see better, they retain visual memory longer or they've improved their decision-making.
Looking at these results, Applebaum said, it appears that prolonged memory retention isn't the reason. But the other two factors might both be in play -- it is possible that the gamers see more immediately, and they are better able make better correct decisions from the information they have available.
To get at this question, the researchers will need more data from brainwaves and MRI imagery to see where the brains of gamers have been trained to perform differently on visual tasks.
This study, which appears in the June edition of the journalAttention, Perception and Psychophysics, was supported by grants from the Army Research Office (54528LS), the Department of Homeland Security (HSHQDC-08-C-00100), DARPA (D12AP00025-002) and Nike Inc.

Story Source:

The above story is reprinted from materials provided byDuke University.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

New Tasks Become as Simple as Waving a Hand With Brain-Computer Interfaces

This image shows the changes that took place in the brain for all patients participating in the study using a brain-computer interface. Changes in activity were distributed widely throughout the brain. (Credit: Jeremiah Wander, UW)



June 11, 2013 — Small electrodes placed on or inside the brain allow patients to interact with computers or control robotic limbs simply by thinking about how to execute those actions. This technology could improve communication and daily life for a person who is paralyzed or has lost the ability to speak from a stroke or neurodegenerative disease.

Now, University of Washington researchers have demonstrated that when humans use this technology -- called a brain-computer interface -- the brain behaves much like it does when completing simple motor skills such as kicking a ball, typing or waving a hand. Learning to control a robotic arm or a prosthetic limb could become second nature for people who are paralyzed.
"What we're seeing is that practice makes perfect with these tasks," said Rajesh Rao, a UW professor of computer science and engineering and a senior researcher involved in the study. "There's a lot of engagement of the brain's cognitive resources at the very beginning, but as you get better at the task, those resources aren't needed anymore and the brain is freed up."
Rao and UW collaborators Jeffrey Ojemann, a professor of neurological surgery, and Jeremiah Wander, a doctoral student in bioengineering, published their results online June 10 in theProceedings of the National Academy of Sciences.
In this study, seven people with severe epilepsy were hospitalized for a monitoring procedure that tries to identify where in the brain seizures originate. Physicians cut through the scalp, drilled into the skull and placed a thin sheet of electrodes directly on top of the brain. While they were watching for seizure signals, the researchers also conducted this study.
The patients were asked to move a mouse cursor on a computer screen by using only their thoughts to control the cursor's movement. Electrodes on their brains picked up the signals directing the cursor to move, sending them to an amplifier and then a laptop to be analyzed. Within 40 milliseconds, the computer calculated the intentions transmitted through the signal and updated the movement of the cursor on the screen.
Researchers found that when patients started the task, a lot of brain activity was centered in the prefrontal cortex, an area associated with learning a new skill. But after often as little as 10 minutes, frontal brain activity lessened, and the brain signals transitioned to patterns similar to those seen during more automatic actions.
"Now we have a brain marker that shows a patient has actually learned a task," Ojemann said. "Once the signal has turned off, you can assume the person has learned it."
While researchers have demonstrated success in using brain-computer interfaces in monkeys and humans, this is the first study that clearly maps the neurological signals throughout the brain. The researchers were surprised at how many parts of the brain were involved.
"We now have a larger-scale view of what's happening in the brain of a subject as he or she is learning a task," Rao said. "The surprising result is that even though only a very localized population of cells is used in the brain-computer interface, the brain recruits many other areas that aren't directly involved to get the job done."
Several types of brain-computer interfaces are being developed and tested. The least invasive is a device placed on a person's head that can detect weak electrical signatures of brain activity. Basic commercial gaming products are on the market, but this technology isn't very reliable yet because signals from eye blinking and other muscle movements interfere too much.
A more invasive alternative is to surgically place electrodes inside the brain tissue itself to record the activity of individual neurons. Researchers at Brown University and the University of Pittsburgh have demonstrated this in humans as patients, unable to move their arms or legs, have learned to control robotic arms using the signal directly from their brain.
The UW team tested electrodes on the surface of the brain, underneath the skull. This allows researchers to record brain signals at higher frequencies and with less interference than measurements from the scalp. A future wireless device could be built to remain inside a person's head for a longer time to be able to control computer cursors or robotic limbs at home.
"This is one push as to how we can improve the devices and make them more useful to people," Wander said. "If we have an understanding of how someone learns to use these devices, we can build them to respond accordingly."
The research team, along with the National Science Foundation's Engineering Research Center for Sensorimotor Neural Engineering headquartered at the UW, will continue developing these technologies.
This research was funded by the National Institutes of Health, the NSF, the Army Research Office and the Keck Foundation.

Story Source:
The above story is reprinted from materials provided byUniversity of Washington. The original article was written by Michelle Ma.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. J. D. Wander, T. Blakely, K. J. Miller, K. E. Weaver, L. A. Johnson, J. D. Olson, E. E. Fetz, R. P. N. Rao, J. G. Ojemann. Distributed cortical adaptation during learning of a brain-computer interface task.Proceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1221127110

Females Fend Off Gut Diseases -- At Least Among Mice

A microscopic image shows an inflamed intestine in a male mouse. MSU professor Laura McCabe and colleagues found that something about female mice seems to protect them from inflammatory bowel disease. (Credit: Image courtesy of Michigan State University)



June 11, 2013 — At least among mice, females have innate protection from certain digestive conditions, according to a new Michigan State University study.

While it's tricky to draw conclusions for human health, the findings could eventually help scientists better understand and treat the 1.4 million Americans suffering from inflammatory bowel diseases, or IBD.
Crohn's disease and colitis, the two most common forms of IBD, involve abnormal functioning of the immune system that can damage the digestive tract, causing inflammation, diarrhea, constipation, abdominal pain and other symptoms.
For the study, researchers induced colitis by giving mice with weakened immune systems a dose of bacteria that can cause digestive trouble. After six weeks, the males had significantly more severe symptoms than the females and had more of the bacteria left in their guts. The males also showed more deterioration of their bones, which studies have linked to gut inflammation.
"It seems females are protected from bad bacteria-induced bone loss, and it's because they have reduced gut inflammation," said co-author Laura McCabe, a professor in the MSU Departments of Physiology and Radiology. "When we looked at markers of inflammation in the male mice, they were really high, whereas the females didn't have that kind of bad response. They can somehow handle these nasty bacteria."
McCabe said while the new study is a step toward better understanding of IBD, it's not clear if women have the same kind of resistance to the condition as the female mice. Indeed, much is still unknown about IBD, including what causes it. The imbalance of good and bad gut bacteria that the experiment simulated is one possible cause.
"We want to know what it is about female mice allowing them to be protected," she said. "If we can understand that, we might have a potential therapeutic target for people with IBD."
The study was funded by the Crohn's and Colitis Foundation of America and appears in the journal Inflammatory Bowel Diseases.
McCabe's partners on the study from the Department of Physiology were Regina Irwin, research technologist; Tae Hyung Lee, research associate; and Narayanan Parameswaran, associate professor. Vincent Young from the University of Michigan also participated.

Story Source:
The above story is reprinted from materials provided byMichigan State University.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Perfect Pitch May Not Be Absolute After All

A new study finds that exposure to music influences how people identify notes from their sound, rather than having the rare ability of perfect pitch at an early age. (Credit: © M. Schuppich / Fotolia)



June 11, 2013 — People who think they have perfect pitch may not be as in tune as they think, according to a new University of Chicago study in which people failed to notice a gradual change in pitch while listening to music.

When tested afterward, people with perfect, or absolute pitch, thought notes made out of tune at the end of a song were in tune, while notes that were in tune at the beginning sounded out of tune.
About one out of 10,000 people has absolute pitch, which means they can accurately identify a note by hearing it. They are frequently able, for instance, to replicate a song on a piano by simply hearing it. Absolute pitch has been "idealized in popular culture as a rare and desirable musical endowment, partly because several well-known composers, such as Mozart, Beethoven, Chopin and Handel, have been assumed to posses absolute pitch," the researchers write in "Absolute Pitch May Not Be So Absolute," in the current issue of Psychological Science.
The study showed that exposure to music influences how people identify notes from their sound, rather than having a rare, absolute ability at an early age. The research also demonstrates the malleability of the brain -- that abilities thought to be stable late in life can change with even a small amount of experience and learning.
One of the researchers, Stephen Hedger, a graduate student in psychology at UChicago, has absolute pitch, as determined by objective tests. Joining him in the study were postdoctoral scholar Shannon Heald and Howard Nusbaum, professor in psychology at UChicago.
Hedger and Heald decided to pursue the study after a session in which Heald tricked Hedger by covertly adjusting pitch on an electronic keyboard.
"Steve and I have talked about absolute pitch, and I thought it might be more malleable than people have thought," Heald said. While in the lab, Hedger began to play a tune, and Heald secretly changed the pitch with a wheel at the side of the keyboard.
Heald changed the tuning to make the music a third of a note flatter than it was at the beginning of the song. Hedger never noticed the change, which was gradual, and was later surprised to discover the music he was playing was actually out of tune at the end.
"I was astounded that I didn't notice the change," Hedger said. Working with Nusbaum, an expert on brain plasticity, they devised experiments to see if other people with absolute pitch would make the same mistake as Hedger.
The researchers recruited 27 people who were identified as having absolute pitch by standard tests and assigned them to two groups for two experiments. The subjects were tested on identifying notes at the beginning of the experiments, and each was able to correctly identify an in-tune note.
One group then listened to Johann Brahms' Symphony No. 1 in C Minor. In another experiment, a second group listened to music played on a French horn to determine whether individual instruments impact the ability to detect music going out of tune.
As the people listened to the symphony, the music was detuned during the first movement (about 15 minutes) to become flatter at the rate of two cents a minute. (The tonal distance between two notes, such as an A and G sharp, is measured as 100 cents).
By the end of the movement, the pitch had been detuned by 33 cents, a change none of the listeners detected, much like Hedger. The symphony was then played out of tune for the next three movements.
The listeners were then tested after listening to the detuned music, as they had been at the beginning of the session. They identified out-of-tune notes from the newly detuned music as being in tune, while reporting notes they heard in the pre-test were slightly out of tune.
Another test composed of only five notes, called phase music, equally found that people with absolute pitch changed what they determined was in tune after listening to the slightly out-of-tune music. That included notes not actually heard as detuned during the musical exposure.
In both tests, only the specific instruments used in the compositions were affected by the detuned nature of the listening experience. Neither the Brahms' Symphony nor the five-note compositions used a piano or French horn, and after listening to detuned music, notes played on these instruments were unaffected.
"Listening to detuned music significantly shifted the perceived intonation and generalized to notes that had not been heard in the detuned music," said Nusbaum. The researchers are now experimenting with people who have more limited pitch identification ability and are finding that their pitch identification can be improved.
"This is further evidence of how adaptable even the adult mind is for learning new skills. We are finding out more and more about how our brains are equipped to learn new things at any age and not limited by abilities previously thought to be available only from the time of birth," Nusbaum said.

Story Source:
The above story is reprinted from materials provided byUniversity of Chicago. The original article was written by William Harms.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Modern Humans Did Not Settle in Asia Before Eruption of Sumatra Volcano 74,000 Years Ago, Study Finds

View of Lake Toba in Sumatra, Indonesia. (Credit: © 12ee12 / Fotolia)



June 11, 2013 — When did modern humans settle in Asia and what route did they take from humankind's African homeland? A University of Huddersfield professor has helped to provide answers to both questions. But he has also had to settle a controversy.


Professor Martin Richards, who heads the University's Archaeogenetics Research Group, co-authors a new article in the Proceedings of the National Academy of Sciences. It refutes a recent theory that there is archaeological evidence for the presence of modern humans in southern Asia before the super-eruption of the Mount Toba volcano in Sumatra. ‌One of the most catastrophic events since humans evolved, it happened approximately 74,000 years ago. In 2005, Professor Richards led research published in an article in the journalScience which used mitochondrial DNA evidence to show that anatomically modern humans dispersed from their Africa homeland via a "southern coastal route" from the Horn and through Arabia, about 60,000 years ago -- after the Toba eruption.‌
‌However, a team of archaeologists excavating in India then claimed to have found evidence that modern humans were there before the eruption -- possibly as early as 120,000 years ago, much earlier than Europe or the Near East were colonised. These findings, based on the discovery of stone tools below a layer of Toba ash, were published in Science in 2007.
Now Professor Richards -- working principally with the archaeologist Professor Sir Paul Mellars, of the University of Cambridge and the University of Edinburgh, with a team including Huddersfield University's Dr Martin Carr and colleagues from York and Porto -- has published his rebuttal of this theory. In doing so, they have been able to draw on a much greater body of DNA evidence that was available for the earlier article.
"One of the things we didn't have in 2005 was very much evidence from India in the way of mitochondrial sequences. Now, with a lot of people doing sequencing and depositing material in databases there are about 1,000 sequences from India," said Professor Richards.
‌By using the mitochondrial DNA of today's populations and working backwards, and by drawing on a wide variety of other evidence and research, the team was able to make much more precise estimates for the arrival of modern humans in India.
‌The evidence suggests dispersal from Africa and settlement in India no earlier than 60,000 years ago. "We also argue that close archaeological similarities between African and Indian stone-tool technologies after 70,000 years ago, as well as features such as beads and engravings, suggest that the slightly later Indian material had an African source," states Professor Richards.
"There were people in India before the Toba eruption, because there are stone tools there, but they could have been Neanderthals -- or some other pre-modern population," he adds.
"The replacement of the presumably archaic humans living previously in South Asia by modern people with these new technologies appears analogous to the replacement of Neanderthals by modern humans in Europe and western Asia 50-40,000 years ago."

Story Source:
The above story is reprinted from materials provided byUniversity of Huddersfield.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal References:
  1. P. Mellars, K. C. Gori, M. Carr, P. A. Soares, M. B. Richards. Genetic and archaeological perspectives on the initial modern human colonization of southern AsiaProceedings of the National Academy of Sciences, 2013; DOI: 10.1073/pnas.1306043110
  2. Vincent Macaulay, Catherine Hill, Alessandro Achilli, Chiara Rengo, Douglas Clarke, William Meehan, James Blackburn, Ornella Semino, Rosaria Scozzari, Fulvio Cruciani, Adi Taha, Norazila Kassim Shaari, Joseph Maripa Raja, Patimah Ismail, Zafarina Zainuddin, William Goodwin, David Bulbeck, Hans-Jürgen Bandelt, Stephen Oppenheimer, Antonio Torroni, and Martin Richard. Single, Rapid Coastal Settlement of Asia Revealed by Analysis of Complete Mitochondrial GenomesScience, 2005; 308 (5724): 1034 DOI: 10.1126/science.1109792
  3. M. Petraglia, R. Korisettar, N. Boivin, C. Clarkson, P. Ditchfield, S. Jones, J. Koshy, M. M. Lahr, C. Oppenheimer, D. Pyle, R. Roberts, J.-L. Schwenninger, L. Arnold, K. White. Middle Paleolithic Assemblages from the Indian Subcontinent Before and After the Toba Super-EruptionScience, 2007; 317 (5834): 114 DOI:10.1126/science.1141564

Monday, June 10, 2013

Master Regulator in Cancer Metastasis Discovered


Mammary epithelial cells that have undergone an epithelial-mesenchymal transition, exhibit a change in cell morphology with actin stress fibers (red) and with focused cell adhesion points (green). (Credit: Dr. Nathalie Meyer-Schaller, University of Basel)


June 10, 2013 — The predominant cause of death in cancer patients is metastasis, the formation of secondary tumors in other organs like the brain, liver, and lungs. Cancer cells detach from the original primary tumor and reach a single cell or group of cells in another organ. The cells of the body normally remain in place through adhering to an extracellular substance. However, cancer cells learn how to release themselves from these bonds and invade surrounding tissues, blood, and the lymphatic system.

The transformation of sedentary, specialized cells into wandering, invasive, and unspecialized cells is called epithelial-mesenchymal transition (EMT), which is central to metastasis. EMT is a multistage process, which is accompanied by a fundamental change in cell morphology and number of genetic programs. The molecular processes that govern EMT, however, are still poorly understood.
Main Switch Found
The research groups of Prof. Gerhard Christofori of the Department of Biomedicine at the University of Basel; Prof. Erik van Nimwegen from the Biozentrum, University of Basel; and Prof. Dirk Schuebeler from the Friedrich Miescher Institute have discovered a master regulator of EMT and metastasis: the transcription factor Sox4 is upregulated in its activity and triggers the expression of a number of genes that play an important role during EMT and metastasis.
In particular, Sox4 promotes the expression of the enzyme Ezh2, a methyltransferase, which generally influences methylation of specific proteins (histones), the packaging of the genetic material, and thus its readability and gene expression. Due to this change in genetic information, the behavior and function of cells are reprogrammed -- a process that is currently observed during metastasis. Such a change in gene expression is also found in patients with malignant cancer and metastasis and correlates with a poor prognosis.
These findings point to the possibility that the inhibition of the transcription factor Sox4 and especially the methyltransferase Ezh2 could hinder metastasis in cancer patients. Appropriate medications are currently being developed but they need to undergo clinical trials before being used in patients. The research was implemented within the framework of the SystemsX.ch-RTD Project "Cell Plasticity."

Story Source:
The above story is reprinted from materials provided byUniversity of Basel, via EurekAlert!, a service of AAAS.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

Journal Reference:
  1. Neha Tiwari, Vijay K. Tiwari, Lorenz Waldmeier, Piotr J. Balwierz, Phil Arnold, Mikhail Pachkov, Nathalie Meyer-Schaller, Dirk Schübeler, Erik van Nimwegen, Gerhard Christofori. Sox4 Is a Master Regulator of Epithelial-Mesenchymal Transition by Controlling Ezh2 Expression and Epigenetic ReprogrammingCancer Cell, 2013; 23 (6): 768 DOI: 10.1016/j.ccr.2013.04.020