New Device Removes Stroke-Causing Blood Clots Better Than Standard Treatment

An experimental device for removing blood clots in stroke patients dramatically outperformed the standard mechanical treatment, according to research presented by UCLA Stroke Center director Dr. Jeffrey L. Saver at the American Stroke Association's 2012 international conference in New Orleans on Feb. 3.

The SOLITAIRE Flow Restoration Device is among an entirely new generation of devices designed to remove blood clots from blocked brain arteries in patients experiencing stroke. It has a self-expanding, stent-like design and, once inserted into a clot using a thin catheter tube, it compresses and traps the clot. The clot is then removed by withdrawing the device, thus reopening the blocked blood vessel.

In the first U.S. clinical trial of SOLITAIRE, the device opened blocked vessels without causing symptomatic bleeding in or around the brain in 61 percent of patients. The standard Food and Drug Administration–approved mechanical device — a corkscrew-type clot remover called the MERCI Retriever — was effective in 24 percent of cases.

The use of the new device also led to better survival three months after a stroke. There was a 17.2 percent mortality rate with the new device, compared with a 38.2 percent rate with the older one.

"This new device heralds a new era in acute stroke care," said Saver, the study's lead author and a professor of neurology at the David Geffen School of Medicine at UCLA. "We are going from our first generation of clot-removing procedures, which were only moderately good in reopening target arteries, to now having a highly effective tool. This really is a game-changing result."

About 87 percent of all strokes are caused by blood clots blocking a blood vessel supplying the brain. The stroke treatment that has received the most study is the FDA–approved clot- busting drug known as tissue plasminogen activator, but this drug must be given within four-and-a-half hours after the onset of stroke symptoms, and even more quickly in older patients.

When clot-busting drugs cannot be used or are ineffective, the clot can sometimes be mechanically removed during, or beyond, the four-and-a-half–hour window. The current study, however, did not compare mechanical clot removal to drug treatment.

For the trial, called SOLITAIRE With the Intention for Thrombectomy (SWIFT), researchers randomly assigned 113 stroke patients at 18 hospitals to receive either SOLITAIRE or MERCI therapy within eight hours of stroke onset, between January 2010 and February 2011. The patients' average age was 67, and 68 percent were male. The time from the beginning of stroke symptoms to the start of the clot-retriever treatment averaged 5.1 hours. Forty percent of the patients had not improved with standard clot-busting medication prior to the study, while the remainder had not received it.

At the suggestion of a safety monitoring committee, the trial was ended nearly a year earlier than planned due to significantly better outcomes with the experimental device.

Other statistically significant findings included:

• 2 percent of SOLITAIRE-treated patients had symptoms of bleeding in the brain, compared with 11 percent of MERCI patients. At the 90-day follow-up, overall adverse event rates, including bleeding in the brain, were similar for the two devices.
• 58 percent of SOLITAIRE-treated patients had good mental/motor functioning at 90 days, compared with 33 percent of MERCI patients.
• The SOLITARE device also opened more vessels when used as the first treatment approach, necessitating fewer subsequent attempts with other devices or drugs.

"Nearly a decade ago, our UCLA Stroke Center team invented the first stroke retrieval device — the MERCI Retriever — and now we are pleased to have helped develop and successfully test a superior, next-generation clot removing device," said Dr. Reza Jahan, associate professor of radiology at UCLA and the study's principal neurointerventional investigator, who also led the pre-clinical studies. "It is exciting to have a highly effective new tool that can improve the outcomes for more stroke patients."

Contacts and sources:
Amy Albin
University of California - Los Angeles Health Sciences

Regular Use Of Vitamin And Mineral Supplements Could Reduce The Risk Of Colon Cancer

Could the use of vitamin and mineral supplements in a regular diet help to reduce the risk of colon cancer and protect against carcinogens? A study published in the Canadian Journal of Physiology and Pharmacology (CJPP) found that rats given regular multivitamin and mineral supplements showed a significantly lower risk of developing colon cancer when they were exposed to carcinogens.

“It has been unclear whether multivitamin supplementation to cancer patients is helpful, has no effect, or is even detrimental during therapy,” commented Dr. Grant Pierce, Editor of CJPP. “This study is important because it gives some direction to cancer patients in desperate need of guidance on the value of multivitamins and minerals administered during cancer.”

The authors studied rats that were fed a high-fat diet (20% fat) over a 32 week period. The rats were divided into 6 groups, which were exposed to different combinations of supplements and carcinogens; the colon carcinogenisis induced in the study rats has characteristics that mimic human colon cancer. Rats fed a high-fat plus low-fibre diet and exposed to carcinogens developed pre-cancerous lesions; whereas, rats undergoing similar treatment, but provided with daily multivitamin and mineral supplements, showed a significant (84%) reduction in the formation of pre-cancerous lesions and did not develop tumours.

The authors conclude that “multivitamin and mineral supplements synergistically contribute to the cancer chemopreventative potential, and hence, regular supplements of multivitamins and minerals could reduce the risk of colon cancer.”

The study “Multivitamin and mineral supplementation in 1,2-dimethylhydrazine induced experimental colon carcinogenesis and evaluation of free radical status, antioxidant potential, and incidence of ACF” appears in the January issue of CJPP.


Contacts and sources:
Ignacimuthu Savarimuthu 
Canadian Science Publishing (NRC Research Press)
www.nrcresearchpress.com/cjpp 

Citation: Arul, A.B., Savarimuthu, I., Alsaif, M.A., Al Numair, K.S. 2012. Multivitamin and mineral supplementation in 1,2-dimethylhydrazine induced experimental colon carcinogenesis and evaluation of free radical status, antioxidant potential, and indicence of ACF. Canadian Journal of Physiology and Pharmacology, 90: 45–54. [Available Open Access on the www.nrcresearchpress.com website.]

Complex Relationship Between Memory And Silence

People who suffer a traumatic experience often don’t talk about it, and many forget it over time. But not talking about something doesn’t always mean you’ll forget it; if you try to force yourself not to think about white bears, soon you’ll be imagining polar bears doing the polka. A group of psychological scientists explore the relationship between silence and memories in a new paper published in Perspectives on Psychological Science, a journal of the Association for Psychological Science.

“There’s this idea, with silence, that if we don’t talk about something, it starts fading,” says Charles B. Stone of Université Catholique de Louvain in Belgium, an author of the paper. But that belief isn’t necessarily backed up by empirical psychological research—a lot of it comes from a Freudian belief that everyone has deep-seated issues we’re repressing and ought to talk about. The real relationship between silence and memory is much more complicated, Stone says.

“We are trying to understand how people remember the past in a very basic way,” Stone says. He cowrote the paper with Alin Coman of the University of Pittsburgh, Adam D. Brown of New York University, Jonathan Koppel of the University of Aarhus, and William Hirst of the New School for Social Research.

“Silence is everywhere,” Stone says. He and his coauthors divide silence about memories into several categories. You might not mention something you’re thinking about on purpose—or because it just doesn’t come up in conversation. And some memories aren’t talked about because they simply don’t come to mind. Sometimes people actively try not to remember something.

One well-studied example used by Stone and his colleagues to demonstrate how subtle the effects of silence can be, establishes that silences about the past occurring within a conversation do not uniformly promote forgetting. Some silences are more likely to lead to forgetting than others. People have more trouble remembering silenced memories related to what they or others talk about than silenced memories unrelated to the topic at hand. If President Bush wanted the public to forget that weapons of mass destruction figured in the build-up to the Iraq War, he should not avoid talking about the war and its build-up. Rather he should talk about the build-up and avoid any discussion of WMDs. And at a more personal level, when people talk to each other about the events of their lives, talking about happy memories may leave the unhappy memories unmentioned, but in the future, people may have more trouble remembering the unmentioned happy memories than the unmentioned sad memories.

Or to supply another example of the subtle relation between memory and silence: If your mother is asking you about your boyfriend and you tell her about yesterday’s date, while thinking—but not talking—about the exciting ending of the date, that romantic finish may linger longer in your memory than if you just answered her questions without thinking about the later part of the evening.

“Silence has important implications for how we remember the past beyond just forgetting,” Stone says. “In terms of memory, not all silence is equal.”
Contacts and sources:
Divya Menon
Association for Psychological Science

New Study Shows How To Boost The Power Of Pain Relief, Without Drugs

Placebos reduce pain by creating an expectation of relief. Distraction—say, doing a puzzle—relieves it by keeping the brain busy. But do they use the same brain processes? Neuromaging suggests they do. When applying a placebo, scientists see activity in the dorsolateral prefrontal cortex. That’s the part of the brain that controls high-level cognitive functions like working memory and attention—which is what you use to do that distracting puzzle.

Now a new study challenges the theory that the placebo effect is a high-level cognitive function. The authors—Jason T. Buhle, Bradford L. Stevens, and Jonathan J. Friedman of Columbia University and Tor D. Wager of the University of Colorado Boulder—reduced pain in two ways – either by giving them a placebo, or a difficult memory task. lacebo. But when they put the two together, “the level of pain reduction that people experienced added up. There was no interference between them,” says Buhle. “That suggests they rely on separate mechanisms.” The findings, published in Psychological Science, a journal of the Association for Psychological Science, could help clinicians maximize pain relief without drugs.

In the study, 33 participants came in for three separate sessions. In the first, experimenters applied heat to the skin with a little metal plate and calibrated each individual’s pain perceptions. In the second session, some of the people applied an ordinary skin cream they were told was a powerful but safe analgesic. The others put on what they were told was a regular hand cream. In the placebo-only trials, participants stared at a cross on the screen and rated the pain of numerous applications of heat—the same level, though they were told it varied. For other trials they performed a tough memory task—distraction and placebo simultaneously. For the third session, those who’d had the plain cream got the “analgesic” and vice versa. The procedure was the same.

The results: With either the memory task or the placebo alone, participants felt less pain than during the trials when they just stared at the cross. Together, the two effects added up; they didn’t interact or interfere with each other. The data suggest that the placebo effect does not require executive attention or working memory.

So what about that neuroimaging? “Neuroimaging is great,” says Buhle, “but because each brain region does many things, when you see activation in a particular area, you don’t know what cognitive process is driving it.” This study tested the theory about how placebos work with direct behavioral observation.

The findings are promising for pain relief. Clinicians use both placebos and distraction—for instance, virtual reality in burn units. But they weren’t sure if one might diminish the other’s efficacy. “This study shows you can use them together,” says Buhle, “and get the maximum bang for your buck without medications.”

Contacts and sources:

Divya Menon
Association for Psychological Science

Scientists Chart High-Precision Map Of Milky Way's Magnetic Fields

Scientists at the Naval Research Laboratory are part of an international team that has pooled their radio observations into a database, producing the highest precision map to date of the magnetic field within our  own Milky Way galaxy.

Fig. 1: The sky map of the Faraday effect caused by the magnetic fields of the Milky Way. Red and blue colors indicate regions of the sky where the magnetic field points toward and away from the observer, respectively. The band of the Milky Way (the plane of the Galactic disk) extends horizontally in this panoramic view. The center of the Milky Way lies in the middle of the image. The North celestial pole is at the top left and the South Pole is at the bottom right. 

Image Credit: Max Planck Institute for Astrophysics

The team, led by the Max Planck Institute for Astrophysics (MPA), used the database they created and were able to apply information theory techniques to produce the map, explains NRL's Dr. Tracy Clarke, a member of the research team. "The key to applying these new techniques is that this project brings together over 30 researchers with 26 different projects and more than 41,000 measurements across the sky. The resulting database is equivalent to peppering the entire sky with sources separated by an angular distance of two full moons." This incredible volume of data results in a new, unique all-sky map that gives scientists the ability to measure the magnetic field structure of the Milky Way in unparalleled detail.

The map shows scientists a quantity known as Faraday depth, a concept that depends on magnetic fields along a specific line of sight. The research team created the map by combining the more than 41,000 individual measurements using a unique image reconstruction technique. The researchers at MPA are specialists in the new discipline of information field theory. Dr. Tracy Clarke, working in NRL's Remote Sensing Division, is part of the team of international radio astronomers who provided the radio observations for the database. The new, high-precision map not only shows the Galactic magnetic field's structure on large scales, it also reveals small-scale features that help scientists better understand turbulence in the Galactic gas.

The Milky Way, along with all other galaxies, possesses magnetic fields. Until now, scientists have been puzzled over the origin of these galactic magnetic fields. The assumption was that the magnetic fields were created by processes where mechanical energy is converted into magnetic energy. These same kinds of processes occur in the interior of the Earth and the Sun. The map that the team has created will give scientists valuable knowledge about the structure of Galactic magnetic fields throughout the Milky Way.

Fig. 2: The uncertainty in the Faraday map. Note that the range of values is significantly smaller than in the Faraday map (Fig. 1). In the area of the celestial south pole, the measurement uncertainties are particularly high because of the low density of data points.

  Image Credit: Max Planck Institute for Astrophysics

For 150 years, scientists have measured cosmic magnetic field by observing the Faraday effect. They know that when polarized light passes though a magnetized medium, the plane of polarization turns. This concept is called Faraday rotation. The strength and direction of the magnetic field governs the amount of rotation that occurs. So scientists observe the rotation to investigate the magnetic fields' properties.

Radio astronomers study the polarized light from distant radio source, passing through the Milky Way on the way to Earth, in order to measure our Galaxy's magnetic field. By measuring the polarization of the light sources at different frequencies, researchers can determine the amount of Faraday rotation.

With these individual measurements, researchers gain data about only a single path through the Galaxy. To gain a fuller picture of the Milky Way's magnetic fields from the Faraday rotation measurements, researchers have to observe many sources across the sky. To achieve this map, radio astronomers from around the world have pooled data from 26 different projects, collecting a total of 41,330 individual measurements. The map contains approximately one radio source per square degree of sky.

Despite this large catalog of date, there are still some large areas, especially in the southern sky, where only a few measurements have been recorded. So to gain a realistic map of the entire sky, researchers have to interpolate between the existing data points that they do have recorded.

There are some difficulties in obtaining the map data this way. First, the accuracy of the various measurements varies greatly although the more exact measurements should have the greatest influence. However scientists are not certain exactly how reliable any single measurement is in providing dependable information about the environment around it. Therefore more accurate measurements are not always given the highest priority.

Fig. 3: In this map of the sky, a correction for the effect of the Galactic disk has been made in order to emphasize weaker magnetic field structures. The magnetic field directions above and below the disk seem to be diametrically opposed, as indicated by the positive (red) and negative (blue) values. An analogous change of direction takes place across the vertical center line, which runs through the center of the Milky Way.

 Image Credit: Max Planck Institute for Astrophysics

There is also the problem of the uncertainty of the measurements simply because the process for obtaining the measurements is highly complex. A seemingly small error can impact the data in a significant way, leading to a distorted map.

To address these problems, the MPA scientists have developed an algorithm used to reconstruct the images. This algorithm, called the "extended critical filter," uses tools provided by the new discipline known as information field theory. Information field theory, which uses logical and statistical methods applied to fields, is an effective tool for dealing with erroneous information. Besides astronomy these tools can be used in fields such as medicine or geography for a range of image and signal-processing applications.

While the new map is particularly important for studying our own Galaxy, researchers will also be able to use it for future studies for extragalactic magnetic fields. This is possible because the scientists will use the new map to help them account for the Galactic contribution to observed Faraday rotation. In the near future astronomers are looking toward a new generation of radio telescopes, such as LOFAR, eVLA, ASKAP, MeerKAT and the SKA that will provide an abundance of measurements of the Faraday effect. With this new data, researchers will be able to provide updates to the image of the Faraday sky, and perhaps someday understand the origin of the galactic magnetic fields.

Contacts and sources:

Donna McKinney
Naval Research Laboratory

A Battle Of The Vampires, 20 Million Years Ago?

They are tiny, ugly, disease-carrying little blood-suckers that most people have never seen or heard of, but a new discovery in a one-of-a-kind fossil shows that “bat flies” have been doing their noxious business with bats for at least 20 million years.

For bats, that’s a long time to deal with a parasite doing its best vampire impression. Maybe it is nature’s revenge on the vampire bat, an aggressive blood consumer in its own right that will feed on anything from sheep to dogs and humans.

The find was made by researchers from Oregon State University in amber from the Dominican Republic that was formed 20-30 million years ago. The bat fly was entombed and perfectly preserved for all that time in what was then oozing tree sap and later became a semi-precious stone.

This is the only known fossil of a bat fly, a specimen at least 20 million years old that carried malaria and fed on the blood of bats. 

Photo by George Poinar, Jr., courtesy of Oregon State University 

This is the only fossil ever found of a bat fly, and scientists say it’s an extraordinary discovery. It was also carrying malaria, further evidence of the long time that malaria has been prevalent in the New World. The genus of bat fly discovered in this research is now extinct.

The findings have been published in two professional journals, Systematic Parasitology and Parasites and Vectors.

“Bat flies are a remarkable case of specific evolution, animals that have co-evolved with bats and are found nowhere else,” said George Poinar, Jr., an OSU professor of zoology and one of the world’s leading experts on the study of ancient ecosystems through plants and animals preserved in amber.

“Bats are mammals that go back about 50 million years, the only true flying mammal, and the earliest species had claws and climbed trees,” Poinar said. “We now know that bat flies have been parasitizing them for at least half that time, and they are found exclusively in their fur. They are somewhat flat-sided like a flea, allowing them to move more easily through bat fur.”

Not every bat is infested with bat flies, and some of the contemporary flies are specific to certain species of bats. But they are still pretty common and found around the world.

Bat flies only leave their bat in order to mate, Poinar said, and that’s probably what this specimen was doing when it got stuck in some sticky, oozing sap.

Contacts and sources:

George Poinar, Jr.
Oregon State University

The study this story is based on is available online: http://bit.ly/y1ekGE

Global Extinction: Gradual Doom Is Just As Bad As Abrupt

Around 250 million years ago, most life on Earth was wiped out in an extinction known as the “Great Dying.” A team led by University of Cincinnati geologist Thomas J. Algeo finds that the end came slowly from thousands of centuries of volcanic activity.

The Permian–Triassic (P–Tr) extinction event, informally known as the Great Dying,was an extinction event that occurred 252.28 Ma (million years) ago, forming the boundary between the Permian and Triassic geologic periods, as well as the Paleozoic and Mesozoic eras. It was the Earth's most severe extinction event, with up to 96% of all marine species and 70% of terrestrial vertebrate species becoming extinct.

The world around the time of the P–Tr extinction.

Credit: Wikipedia

It is the only known mass extinction of insects. Some 57% of all families and 83% of all genera were killed. Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event. This event has been described as the "mother of all mass extinctions.

A painstakingly detailed investigation shows that mass extinctions need not be sudden events. The deadliest mass extinction of all took a long time to kill 90 percent of Earth’s marine life, and it killed in stages, according to a newly published report.

Thomas J. Algeo, professor of geology at the University of Cincinnati, worked with 13 co-authors to produce a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. Their analysis, published Feb. 3 in the Geological Society of America Bulletin, provides strong evidence that Earth’s biggest mass extinction phased in over hundreds of thousands of years.

Thomas J. Algeo 

Credit: University of Cincinnati 

About 252 million years ago, at the end of the Permian period, Earth almost became a lifeless planet. Around 90 percent of all living species disappeared then, in what scientists have called “The Great Dying.” Algeo and colleagues have spent much of the past decade investigating the chemical evidence buried in rocks formed during this major extinction.



The world revealed by their research is horrific and alien: a devastated landscape, barren of vegetation and scarred by erosion from showers of acid rain, huge “dead zones” in the oceans, and runaway greenhouse warming leading to sizzling temperatures.

The evidence that Algeo and his colleagues are looking at points to massive volcanism in Siberia. A large portion of western Siberia reveals volcanic deposits up to five kilometers (three miles) thick, covering an area equivalent to the continental United States. And the lava flowed where it could most endanger life, through a large coal deposit.

“The eruption released lots of methane when it burned through the coal,” he said. “Methane is 30 times more effective as a greenhouse gas than carbon dioxide. We’re not sure how long the greenhouse effect lasted, but it seems to have been tens or hundreds of thousands of years.”

A lot of the evidence ended up being washed into the ocean, and it is among fossilized marine deposits that Algeo and his colleagues look for it. Previous investigations have focused on deposits created by a now vanished ocean known as Tethys, a kind of precursor to the Indian Ocean. Those deposits, in South China particularly, record a sudden extinction at the end of the Permian.

“In shallow marine deposits, the latest Permian mass extinction was generally abrupt,” Algeo said. “Based on such observations, it has been widely inferred that the extinction was a globally synchronous event.”

Recent studies are starting to challenge that view.

Algeo and his co-authors focused on rock layers at West Blind Fiord on Ellesmere Island in the Canadian Arctic. That location, at the end of the Permian, would have been a lot closer to the Siberian volcanoes than sites in South China.

The Canadian sedimentary rock layers are 24 meters (almost 80 feet) thick and cross the Permian-Triassic boundary, including the latest Permian mass extinction horizon. The investigators looked at how the type of rock changed from the bottom to the top of the section. They looked at the chemistry of the rocks. They looked at the fossils contained in the rocks.

They discovered a total die-off of siliceous sponges about 100,000 years earlier than the marinemass extinction event recorded at Tethyan sites. Chemical clues, Algeo said, confirm that life on land was in crisis. Dying plants and eroding soil were being flushed into the ocean where the over-abundant nutrients led to a microbial feeding frenzy and the removal of oxygen – and life – from the late Permian ocean.

What appears to have happened, according to Algeo and his colleagues, is that the effects of early Siberian volcanic activity, such as toxic gases and ash, were confined to the northern latitudes. Only after the eruptions were in full swing did the effects reach the tropical latitudes of the Tethys Ocean.

The research was supported by the National Science Foundation, Canadian Natural Sciences and Engineering Research Council and the National Aeronautics and Space Administration Exobiology Program.

Contacts and sources:

Greg Hand
University of Cincinnati

Powerful 3D Animation Tool Shows Complexity Of A Single Cell, Wins International Visualization Award

A powerful 3D animation tool created by Graham Johnson at The Scripps Research Institute has been selected as the winning video in the ninth annual International Science and Engineering Visualization Challenge.

The competition, co-sponsored by the National Science Foundation (NSF) and the journal Science, is designed to celebrate and encourage the visual communication of science for education and journalistic purposes. This year, 212 entries were received from 33 countries, representing every continent except Antarctica. For the first time this year, the public participated in the voting process, selecting their favorite images as People's Choice winners.

A single cell

Credit: Scripps Research Institute

Johnson’s entry—the result of a collaboration with Andrew Noske of the National Center for Microscopy & Imaging Research and Bradley Marsh of the Institute for Molecular Bioscience at the University of Queensland—was selected as a first-place winner in the video category by both the judges and through People’s Choice.

To create the winning entry, Johnson, Noske, and Marsh worked to create a prototype of Marsh’s long-term goal of visually simplifying the complex 3D data sets collected in his lab through an imaging technique known as tomography.

Their winning video, “Rapid Visual Inventory & Comparison of Complex 3D Structures,” illustrates the tool that enables scientists to compare and contrast multiple parameters of complicated structures, like those found in whole-cell tomograms, at a glance. The video shows how the tool can morph beta cells into simplified geometric versions to enable the visual comparison of the organelle volumes of a single cell and how it can compare relationships between four beta cells collected by Noske, Marsh, and colleagues under different physiological conditions.

Credit: Scripps Research Institute

“Scientists and general audiences alike can learn a great deal about biology by comparing the internal structural differences between cells harvested from different environments, say from different parts of your body or different lifecycle stages,” said Johnson, an alumnus of the Scripps Research Institute’s Kellogg School of Science and Technology and a newly appointed QB3@University of California San Francisco Faculty Fellow. “Morphing the cell from the complicated native model to the simplified version and back gets general audiences excited about the subject matter and reminds even expert audiences of the complex interplay of randomness and specific interaction that enables life to exist.”

Johnson, Noske, and Marsh’s video and other winning entries appear in the February 3 issue of Science (see www.sciencemag.org andhttp://www.sciencemag.org/content/335/6068/534.abs), as well as on the NSF website (see www.nsf.gov). It can also be viewed on YouTube athttp://www.youtube.com/grahamj21?v=Dl1ufW3cj4g&lr=1

Contacts and sources: 

Mika Ono  
Scripps Research Institute

Surface Of Mars An Unlikely Place For Life After 600 Million Year Drought, Say Scientists

Mars may have been arid for more than 600 million years, making it too hostile for any life to survive on the planet’s surface, according to researchers who have been carrying out the painstaking task of analysing individual particles of Martian soil. Dr Tom Pike, from Imperial College London, will discuss the team’s analysis at a European Space Agency (ESA) meeting on 7 February 2012.

The researchers have spent three years analysing data on Martian soil that was collected during the 2008 NASA Phoenix mission to Mars. Phoenix touched down in the northern arctic region of the planet to search for signs that it was habitable and to analyse ice and soil on the surface.

The results of the soil analysis at the Phoenix site suggest the surface of Mars has been arid for hundreds of millions of years, despite the presence of ice and the fact that previous research has shown that Mars may have had a warmer and wetter period in its earlier history more than three billion years ago. The team also estimated that the soil on Mars had been exposed to liquid water for at most 5,000 years since its formation billions of years ago. They also found that Martian and Moon soil is being formed under the same extremely dry conditions.

Satellite images and previous studies have proven that the soil on Mars is uniform across the planet, which suggests that the results from the team’s analysis could be applied to all of Mars. This implies that liquid water has been on the surface of Mars for far too short a time for life to maintain a foothold on the surface.

Figure 1. Micrographs of Martian soil collected from (a) Mama Bear, surface at Goldilocks trench (sol 31);
(b) Rosy Red, surface near Snow White trench (sol 31); (c) Sorceress, sublimation lag from Snow White trench (sol 44); (d) Golden Key, sublimation pile from Dodo-Goldilocks trench (sol 103); (e) Golden Goose, subsurface  from Stone Soup Trench (sol 112); (f) Galloping Hessian, surface sample below Headless rock near Neverland Trench (sol 132); (g) Wicked Witch, sublimation lag from Snow White trench (sol 122). Middle frame: The locations in the work area. Images of the lag deposit from the soil-rich ice in Figures 1c and 1g appear similar to the other soils, suggesting contemporaneous ice formation. Golden Key (Figure 1d) has a markedly greater proportion of large grains, indicative of entrainment of soil produced under different sorting conditions.

Credit:  W. T. Pike, U. Staufer, M. H. Hecht, W. Goetz, D. Parrat, H. Sykulska-Lawrence, S. Vijendran, and M. B. Madsen,

Dr Pike, from the Department of Electrical and Electronic Engineering at Imperial, who is lead author on the study published in the journal Geophysical Research Letters, explains:

“We found that even though there is an abundance of ice, Mars has been experiencing a super-drought that may well have lasted hundreds of millions of years. We think the Mars we know today contrasts sharply with its earlier history, which had warmer and wetter periods and which may have been more suited to life. Future NASA and ESA missions that are planned for Mars will have to dig deeper to search for evidence of life, which may still be taking refuge underground.”

During the Phoenix mission, Dr Pike and his research group formed one of 24 teams based at mission control in the University of Arizona in the USA, operating part of the spacecraft’s onboard laboratories. They analysed soil samples dug up by a robot arm, using an optical microscope to produce images of larger sand-sized particles, and an atomic-force microscope to produce 3D images of the surface of particles as small as 100 microns across. Since the end of the mission, the team has been cataloguing individual particle sizes to understand more about the history of the Martian soil.

In the study, the researchers looked for the microscopic clay particles that are formed when rock is broken down by water. Such particles are an important marker of contact between liquid water and the soil, forming a distinct population in the soil. The team found no such marker. They calculated that even if the few particles they saw in this size range were in fact clay, they made up less than 0.1 percent of the total proportion of the soil in the samples. On Earth, clays can make up to 50 percent or more of the soil content, so such a small proportion in the Martian samples suggests that the soil has had a very arid history.

They estimated that the soil they were analysing had only been exposed to liquid water for a maximum of 5,000 years by comparing their data with the slowest rate that clays could form on Earth.

The team found further evidence to support the idea that Martian soil has been largely dry throughout its history by comparing soil data from Mars, Earth and the Moon. The researchers deduced that the soil was being formed in a similar way on Mars and the Moon because they were able to match the distribution of soil particle sizes. On Mars, the team inferred that physical weathering by the wind as well as meteorites breaks down the soil into smaller particles. On the Moon, meteorite impacts break down rocks into soil, as there is no liquid water or atmosphere to wear down the particles.

This research has received support from the UK Science and Technology Facilities Council; the Danish Research Agency; the Wolfermann-Nägeli Foundation, Switzerland; the Space Center at EPFL, Switzerland; the Swiss National Science Foundation; and the National Aeronautics and Space Administration.

Contacts and sources:

Imperial College London

Citation:  W. T. Pike, U. Staufer, M. H. Hecht, W. Goetz, D. Parrat, H. Sykulska-Lawrence, S. Vijendran, and M. B. Madsen, “Quantification of the dry history of the Martian soil inferred from in situ microscopy” Geophysical Research Letter, Vol. 38, December 2011 edition, doi:10.1029/2011GL049896, 2011. For a copy of the paper: https://fileexchange.imperial.ac.uk/files/aafc223436/2011GL049896.pdf

10 Once-Dominant Businesses That Ended Up Declaring Bankruptcy

When a company's name becomes practically synonymous with the industry it's in, it seems impossible that the business could ever fail. It'd be like Coca-Cola going under even though a large chunk of the population refer to all sodas as "Coke." But even the most recognizable businesses sometimes can't adjust to changes in the market or overcome financial troubles. These companies were once the top in their field, but fell to the point where filing bankruptcy was their best option.

1. Kodak

We're barely into 2012 and a major company has already filed for bankruptcy. Eastman Kodak, the groundbreaking photography company that's been around since the late 1800s, saw its stock drop 35% after they filed for Chapter 11 bankruptcy in January. The age of digital photography seems to have caused some innovation problems for the business that made a name for itself by selling cheap cameras and making most of their profit through film and supplies to print photos. Once those money-making elements started to become obsolete, Eastman Kodak found itself with $6.75 billion in debt. Not exactly a Kodak moment for the company.

2. Enron

Even if you were too young to understand it all when the trouble went down, you've probably at least heard of Enron, which became synonymous with corporate greed and corruption. In 2000, the company was considered a leading business in electricity and natural gas, along with several other services. By the end of 2001, Enron had filed for bankruptcy after it came out that they'd been cooking the books regularly. The scandal affected corporations all over the U.S. by calling into question corporate accounting practices in general, which led to a federal investor protection act, and affected employees and investors with the company who lost jobs or huge amounts of money (or both).

3. Blockbuster

We still remember Blockbuster, right? We used to go there before hosting a slumber party or having a date night at home to pick up the newest releases to snuggle up to. There's no doubt that it stole the show from its red-headed stepbrother, Hollywood Video, and any mom-and-pop rental stores in town. Once RedBox and Netflix came around, though, it was harder for Blockbuster to hold onto their dominance in the home entertainment industry, and in 2010, the company was forced to file for bankruptcy. Dish Network won the enterprise at auction in 2011.

4. Schwinn Bicycle Company

Schwinn has been the quintessential bike for kids and adults alike since the company gained overwhelming popularity in the '60s. So you'd probably be surprised to hear that the company of the perfect cruising bike has declared bankruptcy twice. By 1990, many other bicycle brands were gaining traction in the market and Schwinn began exporting production to save money. By 1993, they had declared bankruptcy. The company was bought by an investment group. In 2001, it filed for bankruptcy again, and was purchased by Pacific Cycle at auction.

5. General Motors

General Motors was consistently considered the leading automaker in the world for 77 years, up until 2007. With mounting debt and a poor economy, the government pushed them toward Chapter 11 bankruptcy in 2009. This company, though, seems to have a success story compared to some other bankruptcy tales, though it's still too soon to see the long-term effects. GM came out of Chapter 11 reorganization (with help from government funds) with an initial public offering that was the highest in history, at $20.1 billion. Some contestants on Wheel of Fortune probably wish they could bounce back from a "Bankrupt" like that.

6. Marvel Entertainment

We don't want to get into a debate over the superiority of Marvel over DC (or vice versa), but there's no denying that Marvel has been one of the top comic book companies for the past couple of decades. The parent company of Marvel Comics, and thus some of your favorite character like Spider-Man, the X-Men, and Captain America, has needed its own hero in its business history. Facing money problems and unable to come to a bailout deal with bondholders, Marvel filed for bankruptcy in 1996. The resulting drama with shareholders could've filled a (very boring) comic book, which would've ended with the merger of Marvel Entertainment and ToyBiz to create Marvel Enterprises.

7. Hugo Boss

Men's fashion leader Hugo Boss' story is kind of backwards compared to the rest of these. While the master tailor was creating great clothes before his bankruptcy, his company is now a giant in the good-looking men industry. Hugo Boss himself started the company in 1924 in a small town in Germany, but because the economy was so tough after World War I, he had to declare bankruptcy after just six years. But in 1931, he picked back up and began building an empire. Today, the company does business in 110 countries with several fashion lines for both men and women.

8. Atkins Nutritionals

Remember that dark time in recent history when people were going around eating nothing but big slabs of meat? Sure, eating few-to-zero carbs helped fat people lose weight, but it also made them look like crazed savages. The company that was encouraging this behavior was Atkins Nutritionals, the biggest name in the no-carb diet fad. Besides the books on the diet, the company also sold low-carb food products to go along with them. Of course, just like with most fad diets, the interest in the Atkins way of eating died down, and in 2005, the company filed for bankruptcy.

9. Lehman Brothers

As the fourth biggest investment bank in the country, you could say Lehman Brothers was pretty important. It was also using some accounting tricks to make it seem more stable than it was, and was eventually brought down by the mortgage crisis. With $613 billion in bank debt and $155 billion in bond debt, Lehman Brothers' filing for bankruptcy in 2008 became the largest bankruptcy in U.S. history.

10. Reader's Digest Association

At some point in your life, you've come across a Reader's Digest magazine, whether it was at a doctor's office or in the pile of reading materials in your grandpa's bathroom. Considering it was first distributed in 1922, it's no surprise that the average reader is, well, really old. And with the trouble print publications have been running into in the last decade, this old-fashioned publication just couldn't pull its weight anymore. Reader's Digest Association has other magazines, but they couldn't escape bankruptcy in 2009.

Contacts and sources:
Roxanne McAnn 

http://www.businessinsurance.org/10-once-dominant-businesses-that-ended-up-declaring-bankruptcy/

Classic Portrait Of A Barred Spiral Galaxy

The NASA/ESA Hubble Space Telescope has taken a picture of the barred spiral galaxy NGC 1073, which is found in the constellation of Cetus (The Sea Monster). Our own galaxy, the Milky Way, is a similar barred spiral, and the study of galaxies such as NGC 1073 helps astronomers learn more about our celestial home.

Most spiral galaxies in the Universe have a bar structure in their centre, and Hubble's image of NGC 1073 offers a particularly clear view of one of these. Galaxies' star-filled bars are thought to emerge as gravitational density waves funnel gas toward the galactic centre, supplying the material to create new stars. The transport of gas can also feed the supermassive black holes that lurk in the centres of almost every galaxy.

Some astronomers have suggested that the formation of a central bar-like structure might signal a spiral galaxy's passage from intense star-formation into adulthood, as the bars turn up more often in galaxies full of older, red stars than younger, blue stars. This storyline would also account for the observation that in the early Universe, only around a fifth of spiral galaxies contained bars, while more than two thirds do in the more modern cosmos.

The NASA/ESA Hubble Space Telescope has taken a picture of the barred spiral galaxy NGC 1073, which is found in the constellation of Cetus (The Sea Monster). Our own galaxy, the Milky Way, is thought to be a similar barred spiral, and the study of galaxies such as NGC 1073 can help astronomers learn more about our celestial home.

 

Credit: NASA and  ESA

While Hubble's image of NGC 1073 is in some respects an archetypal portrait of a barred spiral, there are a couple of quirks worth pointing out.

One, ironically, is almost — but not quite — invisible to optical telescopes like Hubble. In the upper left part of the image, a rough ring-like structure of recent star formation hides a bright source of X-rays. Called IXO 5, this X-ray source is likely to be a binary system featuring a black hole and a star orbiting each other.

Comparing X-ray observations from the Chandra spacecraft with this Hubble image, astronomers have narrowed the position of IXO 5 down to one of two faint stars visible here. However, X-ray observations with current instruments are not precise enough to conclusively determine which of the two it is.

Hubble's image does not only tell us about a galaxy in our own cosmic neighbourhood, however. We can also discern glimpses of objects much further away, whose light tells us about earlier eras in cosmic history.

Right across Hubble's field of view, more distant galaxies are peering through NGC 1073, with several reddish examples appearing clearly in the top left part of the frame.

This video zooms from an image of constellation of Cetus (the Sea Monster) into a closeup of the galaxy NGC 1073, imaged by the NASA/ESA Hubble Space Telescope. Our own galaxy, the Milky Way, is thought to have a similar barred spiral shape, and the study of galaxies such as NGC 1073 can help astronomers learn more about our celestial home.

Credit: NASA, ESA, Digitized Sky Survey 2, Adam Block/Mount Lemmon SkyCenter/University of Arizona

More intriguing still, three of the bright points of light in this image are neither foreground stars from the Milky Way, nor even distant stars in NGC 1073. In fact they are not stars at all. They are quasars, incredibly bright sources of light caused by matter heating up and falling into supermassive black holes in galaxies literally billions of light-years from us. The chance alignment through NGC 1073, and their incredible brightness, might make them look like they are part of the galaxy, but they are in fact some of the most distant objects observable in the Universe.


Contacts and sources:
Oli Usher
ESA/Hubble Information Centre

New Procedure Repairs Severed Nerves In Minutes, Restoring Limb Use In Days Or Weeks

Team apply new procedure to rapidly induce nerve regeneration in mammals

American scientists believe a new procedure to repair severed nerves could result in patients recovering in days or weeks, rather than months or years. The team used a cellular mechanism similar to that used by many invertebrates to repair damage to nerve axons. Their results are published today in theJournal of Neuroscience Research.

"We have developed a procedure which can repair severed nerves within minutes so that the behavior they control can be partially restored within days and often largely restored within two to four weeks," said Professor George Bittner from the University of Texas. "If further developed in clinical trials this approach would be a great advance on current procedures that usually imperfectly restore lost function within months at best."

The team studied the mechanisms all animal cells use to repair damage to their membranes and focused on invertebrates, which have a superior ability to regenerate nerve axons compared to mammals. An axon is a long extension arising from a nerve cell body that communicates with other nerve cells or with muscles.

This research success arises from Bittner's discovery that nerve axons of invertebrates which have been severed from their cell body do not degenerate within days, as happens with mammals, but can survive for months, or even years.

The severed proximal nerve axon in invertebrates can also reconnect with its surviving distal nerve axon to produce much quicker and much better restoration of behaviour than occurs in mammals.

"Severed invertebrate nerve axons can reconnect proximal and distal ends of severed nerve axons within seven days, allowing a rate of behavioural recovery that is far superior to mammals," said Bittner. "In mammals the severed distal axonal stump degenerates within three days and it can take nerve growths from proximal axonal stumps months or years to regenerate and restore use of muscles or sensory areas, often with less accuracy and with much less function being restored."

The team described their success in applying this process to rats in two research papers published today. The team were able to repair severed sciatic nerves in the upper thigh, with results showing the rats were able to use their limb within a week and had much function restored within 2 to 4 weeks, in some cases to almost full function.

"We used rats as an experimental model to demonstrate how severed nerve axons can be repaired. Without our procedure, the return of nearly full function rarely comes close to happening," said Bittner. "The sciatic nerve controls all muscle movement of the leg of all mammals and this new approach to repairing nerve axons could almost-certainly be just as successful in humans."

To explore the long term implications and medical uses of this procedure, MD's and other scientist- collaborators at Harvard Medical School and Vanderbilt Medical School and Hospitals are conducting studies to obtain approval to begin clinical trials.

"We believe this procedure could produce a transformational change in the way nerve injuries are repaired," concluded Bittner.


Contacts and sources:
Ben Norman
Wiley-Blackwell

Penn Anthropologists Clarify Link Between Asians And Early Native Americans

A tiny mountainous region in southern Siberia may have been the genetic source of the earliest Native Americans, according to new research by a University of Pennsylvania-led team of anthropologists.

Lying at the intersection of what is today Russia, Mongolia, China and Kazakhstan, the region known as the Altai “is a key area because it’s a place that people have been coming and going for thousands and thousands of years,” said Theodore Schurr, an associate professor in Penn’s Department of Anthropology. Schurr, together with doctoral student Matthew Dulik and a team of graduate students and postdoctoral researchers, collaborated on the work with Ludmila Osipova of the Institute of Cytology and Genetics in Novosibirsk, Russia.

Matthew Dulik and Theodore Schurr

 Credit: University of Pennsylvania

Among the people who may have emerged from the Altai region are the predecessors of the first Native Americans. Roughly 20-25,000 years ago, these prehistoric humans carried their Asian genetic lineages up into the far reaches of Siberia and eventually across the then-exposed Bering land mass into the Americas.

“Our goal in working in this area was to better define what those founding lineages or sister lineages are to Native American populations,” Schurr said.

The team’s study, published in the American Journal of Human Genetics, analyzed the genetics of individuals living in Russia’s Altai Republic to identify markers that might link them to Native Americans. Prior ethnographic studies had found distinctions between tribes in the northern and southern Altai, with the northern tribes apparently linked linguistically and culturally to ethnic groups farther to the north, such as the Uralic or Samoyedic populations, and the southern groups showing a stronger connection to Mongols, Uighurs and Buryats.

Schurr and colleagues assessed the Altai samples for markers in mitochondrial DNA, which is maternally inherited, and in Y chromosome DNA, which is passed from fathers to sons. They also compared the samples to ones previously collected from individuals in southern Siberia, Central Asia, Mongolia, East Asia and a variety of American indigenous groups. Because of the large number of gene markers examined, the findings have a high degree of precision.

“At this level of resolution we can see the connections more clearly,” Schurr said.

Looking at the Y chromosome DNA, the researchers found a unique mutation shared by Native Americans and southern Altaians in the lineage known as Q.

“This is also true from the mitochondrial side,” Schurr said. “We find forms of haplogroups C and D in southern Altaians and D in northern Altaians that look like some of the founder types that arose in North America, although the northern Altaians appeared more distantly related to Native Americans."

Calculating how long the mutations they noted took to arise, Schurr’s team estimated that the southern Altaian lineage diverged genetically from the Native American lineage 13,000 to 14,000 years ago, a timing scenario that aligns with the idea of people moving into the Americas from Siberia between 15,000 and 20,000 years ago.

Though it’s possible, even likely, that more than one wave of people crossed the land bridge, Schurr said that other researchers have not yet been able to identify a similar geographic focal point from which Native Americans can trace their heritage.

“It may change with more data from other groups, but, so far, even with intensive work in Mongolia, they’re not seeing the same things that we are,” he said.

In addition to elucidating the Asia-America connection, the study confirms that the modern cultural divide between southern and northern Altaians has ancient genetic roots. Southern Altaians appeared to have had greater genetic contact with Mongolians than they did with northern Altaians, who were more genetically similar to groups farther to the north.

However, when looking at the Altaians’ mitochondrial DNA in isolation, the researchers did observe greater connections between northern and southern Altaians, suggesting that perhaps females were more likely to bridge the genetic divide between the two populations.

“Subtle differences here both reflect the Altaians themselves — the differentiation among those groups — and allow us to try to point to an area where some of these precursors of American Indian lineages may have arisen,” Schurr said.

Moving forward, Schurr and his team hope to continue to use molecular genetic techniques to trace the movement of peoples within Asia and into and through the Americas. They may also attempt to identify links between genetic variations and adaptive physiological responses, links that could inform biomedical research.

For example, Schurr noted that both Siberians and Native American populations “seem to be susceptible to Westernization of diet and moving away from traditional diets, but their responses in terms of blood pressure and fat metabolism and so forth actually differ.”

Using genomic approaches along with traditional physical anthropology may lend insight into the factors that govern these differences.

In addition to Schurr and Dulik, the research was conducted by Sergey Zhadanov, Ayken Askapuli, Lydia Gau, Omer Gokcumen and Samara Rubinstein of Penn’s Department of Anthropology.

The study was supported by the University of Pennsylvania, the National Science Foundation, the Social Sciences and Humanities Research Council of Canada and the Russian Basic Fund for Research. The National Geographic Society also provided infrastructural support to the Schurr lab.


Contacts and sources:
University of Pennsylvania

Football Findings Suggest Concussions Caused By Series Of Hits

A two-year study of high school football players suggests that concussions are likely caused by many hits over time and not from a single blow to the head, as commonly believed.

Purdue University researchers have studied football players for two seasons at Jefferson High School in Lafayette, Ind., where 21 players completed the study the first season and 24 the second season, including 16 repeating players.

Helmet-sensor impact data from each player were compared with brain-imaging scans and cognitive tests performed before, during and after each season.

Members of the Jefferson High School football team, seen here during a practice last season, were monitored in research to learn how impacts to the head affect brain function.

Credit: Purdue University file photo/Andrew Hancock

"The most important implication of the new findings is the suggestion that a concussion is not just the result of a single blow, but it's really the totality of blows that took place over the season," saidEric Nauman, an associate professor of mechanical engineering and an expert in central nervous system and musculoskeletal trauma. "The one hit that brought on the concussion is arguably the straw that broke the camel's back."

Researchers evaluated players using a type of brain imaging technology called functional magnetic resonance imaging, or fMRI, along with a computer-based neurocognitive screening test. The fMRI scans reveal which parts of the brain are most active during specific tasks.

Thomas Talavage, an expert in functional neuroimaging and co-director of the Purdue MRI Facility, said the scans indicate players are adapting their mental processes to deal with brain changes.

"The changes in brain activity we are observing suggest that a player is having to use a different strategy to perform a task, and that is likely because functional capacity is reduced," Talavage said. "The level of change in the fMRI signal is significantly correlated to the number and distribution of hits that a player takes. Performance doesn't change, but brain activity changes, showing that certain areas are no longer being recruited to perform a task."

Brain scans show differences among high school football players in a two-year study that suggests concussions are likely caused by many hits over time and not from a single blow to the head, as commonly believed. 

 Purdue University image/Thomas Talavage
Findings, detailed in a paper to appear online in the Journal of Biomechanics, are contrary to conventional thinking.

"Most clinicians would say that if you don't have any concussion symptoms you have no problems," said Larry Leverenz, an expert in athletic training and a clinical professor of health and kinesiology. "However, we are finding that there is actually a lot of change, even when you don't have symptoms."

The paper was written by mechanical engineering graduate student Evan Breedlove, Nauman, Leverenz, Talavage, former Purdue professor of educational studies Jeffrey Gilger, biomedical engineering graduate student Meghan Robinson, health and kinesiology graduate student Katherine E. Morigaki, electrical and computer engineering graduate student Umit Yoruk, mechanical engineering undergraduate student Kyle O'Keefe, and undergraduate student in electrical and computer engineering Jeffrey King. Gilger is now a researcher at the University of California, Merced.

The research may help to determine how many blows it takes to cause impairment, which could lead to safety guidelines on limiting the number of hits a player receives per week.

"Any change in fMRI data is a concern, but we don't yet know what these changes mean, what they translate to, in terms of cognitive impairment," Breedlove said.

A common assumption in sports medicine is that certain people are innately more susceptible to head injury. However, the new findings suggest the number of hits received during the course of a season is the most important factor, Talavage said.

"Over the two seasons we had six concussed players, but 17 of the players showed brain changes even though they did not have concussions," Talavage said. "There is good correlation with the number of hits players received, but we need more subjects."

The researchers have expanded the study to include an additional high school football team and girls' soccer.

"We want to increase the number of football players in the study and also include soccer to study athletes who don't wear head protection," Nauman said. "We also want to include girls to see whether they are affected differently than boys."

The research findings represent a dilemma because they suggest athletes may suffer a form of injury that is difficult to diagnose.

"This might be especially important in young people because the brain is still developing, so even though subtle unexpressed damage doesn't manifest as a concussion it could affect the brain later in life," Gilger said.

Changes were seen in regions of the brain that have been associated with chronic traumatic encephalopathy (CTE), a progressive degenerative disease found in people who suffer numerous concussions and other forms of head injury.

"This is still circumstantial evidence, but it suggests that whether you are concussed or not your brain is changing as a result of all these hits, and the regions most affected are the ones that exhibit CTE," Nauman said.

Players in the study received from 200 to nearly 1,900 hits to the head in a single season, with two players exceeding 1,800 hits. Helmet-sensor data indicated impact forces to the head ranged from 20 Gs to more than 100 Gs.

"The worst hit we've seen was almost 300 Gs," Nauman said.

A soccer player "heading" a ball experiences an impact of about 20 Gs.

Findings could aid efforts to develop more sensitive and accurate methods to detect cognitive impairment and concussions; more accurately characterize and model cognitive deficits that result from head impacts; determine the cellular basis for cognitive deficits after a single impact or repeated impacts; and develop new interventions to reduce the risk and effects of head impacts.

"Now that we know there is definitely a buildup of damage before the concussion occurs, ultimately, there is hope that we can do more to prevent concussions," Nauman said.

The work is ongoing and supported with grants from the Indiana State Department of Health's Spinal Cord and Brain Injury Research Fund, General Electric Healthcare, the Indiana Clinical and Translational Sciences Institute, and through the National Science Foundation and National Defense Science and Engineering Graduate Fellowships.

Researchers also will follow the case studies of players who take the most hits to see if there is evidence of permanent changes in brain structure using MRI scans.

The research group, called the Purdue Neurotrauma Group (PNG), also is studying ways to reduce traumatic brain injury in soldiers who suffer concussions caused by shock waves from explosions.


Contacts and sources:
Written by Emil Venere
Purdue University

Citation: Biomechanical Correlates of Symptomatic and Asymptomatic Neurophysiological Impairment in High School Football

Evan L. Breedlove, BS1,Thomas M. Talavage, PhD2,3,Meghan Robinson, BS2, Katherine E. Morigaki, MS ATC4,Umit Yoruk, BS3, Larry J. Leverenz, PhD ATC4, Jeffrey W. Gilger, PhD5, Eric A. Nauman, PhD1,2,6

1 School of Mechanical Engineering, Purdue University

2 Weldon School of Biomedical Engineering, Purdue University

3 School of Electrical and Computer Engineering, Purdue University

4 Department of Health and Kinesiology, Purdue University

5 Department of Educational Studies, Purdue University

6 Department of Basic Medical Sciences, Purdue University

Scientists Coax Shy Microorganisms To Stand Out In A Crowd

The communities of marine microorganisms that make up half the biomass in the oceans and are responsible for half the photosynthesis the world over, mostly remain enigmatic. A few abundant groups have had their genomes described, but the natures and functions of the rest remain mysterious.

Understanding how the changing global environment might affect these important ecosystem players is like trying to understand the solar system when all you can discern are the brightest objects in the sky.

Now University of Washington scientists have advanced a method that allowed them to single out a marine microorganism and map its genome even though the organism made up less than 10 percent of a water sample teeming with many millions of individuals from dozens of identifiable groups of microbes.

A graphical view of tens of millions of bases of DNA extracted from a marine microbial community found in Puget Sound reveals the entangled genomes of bacteria, archaea and viruses. University of Washington scientists extracted two million of these to map the genome of one particular marine microorganism that had defied investigation.

 

Credit: V Iverson/U of Washington

Typically researchers have had to isolate an organism and culture it in a lab before they could begin to crack its genome.

"We've done the opposite," said Vaughn Iverson, a UW doctoral student in oceanography and lead author of a report in the Feb. 2 issue of the journal Science.

"We went to the environment, didn't make any attempt to isolate any of the organisms in a laboratory sense and, instead, extracted the DNA from everything in the sample," he said. "It's a technique known as metagenomics. The UW's innovation was to develop computational methods to simultaneously sequence all the parts and then reconstruct the chosen genome."

The researchers determined the genome of a member of the marine group II Euryarchaeota, something that has defied investigators since those microorganisms were first detected about a decade ago. They are found widely across the world's oceans so – although not always abundant – biologists assume they have some important function, said Virginia Armbrust, UW professor of oceanography and corresponding author on the Science paper. The resulting genome offers hints that Euryarchaeota might serve as a kind of cleanup crew after diatoms, another ocean microorganism, bloom and die.

"Ocean microorganisms are regulators of large biogeochemical cycles so we need to understand the different members of those communities," Armbrust said. "As we change coastal communities – for better or for worse – we need to understand the players that are there."

The genome also clarified the origin of a gene that allows marine group II Euryarchaeota, as well as many marine bacteria, to harvest energy directly from sunlight, with no photosynthesis involved.

The approach advanced by the UW team isn't just useful for studying microorganisms in the oceans, but also for those found in soils and algal communities with potential for biofuels, or for understanding emerging strains of antibiotic-resistant bacteria that threaten human or animal health, Iverson said. The UW approach takes less time and money.

"Having to culture things to sequence them is an extra step and time consuming if they're difficult to culture," he said. "It becomes a chicken and egg problem. If you have never been able to study it, you don't know what it needs. But in order to study it, you must provide the environment in the lab that it requires."

"If microbiologists can get the DNA directly and sequence it without having to culture it, that's a big advantage."

Metagenomics – extracting DNA from whole microbial communities and sequencing it to reveal genes – has been used for about a decade with marine microorganisms. Sequencing equipment and methods have leapt forward since then, thanks to many researchers and companies, the UW scientists said.

But previous techniques allowed scientists to reconstruct an organism's genome only if the organism made up a third or more of a sample. The UW team showed how to construct the genome of marine group II Euryarchaeota even though it comprised only 7 percent of the cells found in 100 liters of water from Puget Sound near Seattle.

The sample was analyzed using equipment purchased with funding to Armbrust from the Gordon and Betty Moore Foundation, which also paid for Iverson's work. The project was conducted in labs run by Armbrust and co-author Robert Morris, a UW assistant professor of oceanography. Other co-authors are Christian Frazar, Chris Berthiaume and Rhonda Morales, all with the UW.

"Now you can afford to get things that are a much smaller fraction of your overall sample," Iverson said. "That's what's really new – to assemble something with a genome that is not closely related to anything else that is known, so there are no templates or references to work from, and to discern organisms making up less than10 percent of a sample from a complex community."


Contacts and sources:
Sandra Hines
University of Washington

"Discovery" Of Atlantis Corrected As Google Earth Ocean Terrain Receives Major Update

Data from Scripps, NOAA sharpen resolution of seafloor maps, correct "discovery" of Atlantis

Credit:  Scripps Institution of Oceanography

Scripps Institution of Oceanography / University of California, San Diego and Internet information giant Google have updated ocean data in its Google Earth application this week, reflecting new bathymetry data assembled by Scripps Institution of Oceanography, UC San Diego, NOAA researchers and many other ocean mapping groups from around the world.

The newest version of Google Earth includes more accurate imagery in several key areas of ocean using data collected by research cruises over the past three years.

"The original version of Google Ocean was a newly developed prototype map that had high resolution but also contained thousands of blunders related to the original archived ship data," said David Sandwell, a Scripps geophysicist. "UCSD undergraduate students spent the past three years identifying and correcting the blunders as well as adding all the multibeam echosounder data archived at the National Geophysical Data Center in Boulder, Colorado."

"The Google map now matches the map used in the research community, which makes the Google Earth program much more useful as a tool for planning cruises to uncharted areas," Sandwell added.

For example, the updated, more precise data corrects a grid-like artifact on the seafloor that was misinterpreted in the popular press as evidence of the lost city of Atlantis off the coast of North Africa.

Through several rounds of upgrades, Google Earth now has 15 percent of the seafloor image derived from shipboard soundings at 1-kilometer resolution. Previous versions only derived about 10 percent of their data from ship soundings and the rest from depths predicted by Sandwell and NOAA researcher Walter Smith using satellite gravity measurements. The two developed the prediction technique in 1994. The satellite and sounding data are combined with land topography from the NASA Shuttle Radar Topography Mission (SRTM) to create a global topography and bathymetry grid called SRTM30_PLUS.

This new version includes all of the multibeam bathymetry data collected by U.S. research vessels over the past three decades including 287 Scripps expeditions from research vessels Washington,Melville and Revelle. UCSD undergraduate student Alexis Shakas processed all the U.S. multibeam data and then worked with Google researchers on the global integration.

The next major upgrade to the grid will occur later this year using a new gravity model having twice the accuracy of previous models. The new gravity information is being collected by a European Space Agency satellite called CryoSat that was launched in February 2010.


Contacts and sources:

Robert Monroe or Mario Aguilera
University of California - San Diego

Magnetic Fields Appear To Evolve With Galaxy Evolution

A CSIRO Summer Vacation student has uncovered details of how galaxies and their magnetic fields evolve together — one of the most challenging problems in astrophysics.

Claire-Elise Green, a second-year Advanced Science student from the University of New South Wales, has been working at CSIRO Astronomy and Space Science in Sydney for nine weeks.

Claire-Elise Green

Image credit: Chris Taylor

"We find magnetic fields throughout space," Ms Green said. "We know they help stars and planets form, but their role in galaxies is less clear."

Magnetic fields can be detected with radio telescopes, because of the effect they have on radio waves.

"Just as light can be polarised by our sunglasses, radio waves can be polarised. Magnetic fields change the direction of this polarisation, so by looking at how the waves are polarised, we can determine the direction of the magnetic fields," explained Ms Green's supervisor, CSIRO astronomer Dr Julie Banfield.

Magnetic fields in space were discovered decades ago, but only recently has it become possible to study them in very distant galaxies.

Ms Green has been using data from US and Canadian radio telescopes to study 136 distant galaxies whose cores produce huge amounts of energy.

These galaxies, called "active galactic nuclei" or AGN, are scattered all across the Universe and are at different stages in their development.

"I'm looking to see if the magnetic fields differ in the different types of these galaxies," she said.

"For instance, I've been looking to see where the magnetic fields start from — the centre of the galaxy, or its outer parts — and whether the magnetic field gets more ordered or changes orientation as galaxies get older."

"What we knew before going into this project is that magnetic fields appear to evolve with galaxy evolution, but we didn't know why or how," said Dr Banfield.

"What Claire-Elise has found is that the location of the magnetic field changes as an AGN evolves from one type to another."

During her time at CSIRO Ms Green has visited the Australia Telescope Compact Array, at Narrabri, NSW, getting the chance to explore galaxies 'hands on' at a telescope as well as from her computer in Marsfield, Sydney.

Ms Green said her vacation scholarship at CSIRO has been an invaluable experience, allowing her to see what astrophysicists do on a day-to-day basis and to learn from and work with them on real-world problems.


Contacts and sources:
Helen Sim 
CSIRO 

Images and audio

 

Hubble Zooms In On Brightest Magnified Galaxy Known

Thanks to the presence of a natural "zoom lens" in space, NASA's Hubble Space Telescope got a uniquely close-up look at the brightest "magnified" galaxy yet discovered.

This observation provides a unique opportunity to study the physical properties of a galaxy vigorously forming stars when the universe was only one-third its present age.

It is one of the most striking examples of gravitational lensing, where the gravitational field of a foreground galaxy bends and amplifies the light of a more distant background galaxy. In this image the light from a distant galaxy, nearly 10 billion light-years away, has been warped into a nearly 90-degree arc of light in the galaxy cluster RCS2 032727-132623. The galaxy cluster lies 5 billion light-years away. The background galaxy’s image is 20 times larger and over three times brighter than typically lensed galaxies. The natural color image was taken in March 2011 with the Hubble Space Telescope’s Wide Field Camera 3.

Credit: NASA; ESA; J. Rigby (NASA Goddard Space Flight Center); and K. Sharon (Kavli Institute for Cosmological Physics, University of Chicago)

A so-called gravitational lens is produced when space is warped by a massive foreground object, whether it is the sun, a black hole or an entire cluster of galaxies. The light from more-distant background objects is distorted, brightened and magnified as it passes through this gravitationally disturbed region.

A team of astronomers led by Jane Rigby of NASA's Goddard Space Flight Center in Greenbelt, Md., aimed Hubble at one of the most striking examples of gravitational lensing, a nearly 90-degree arc of light in the galaxy cluster RCS2 032727-132623. Hubble's view of the distant background galaxy is significantly more detailed than could ever be achieved without the help of the gravitational lens.

The results have been accepted for publication in the Astrophysical Journal, in a paper led by Keren Sharon of the Kavli Institute for Cosmological Physics at the University of Chicago. Professor Michael Gladders and graduate student Eva Wuyts of the University of Chicago were also key team members.

This graphic shows a reconstruction (at lower left) of the brightest galaxy whose image has been distorted by the gravity of a distant galaxy cluster. The small rectangle in the center shows the location of the background galaxy on the sky if the intervening galaxy cluster were not there. The rounded outlines show distinct, distorted images of the background galaxy resulting from lensing by the mass in the cluster. The image at lower left is a reconstruction of what the lensed galaxy would look like in the absence of the cluster, based on a model of the cluster's mass distribution derived from studying the distorted galaxy images.

Credit: NASA, ESA, and Z. Levay (STScI)

The presence of the lens helps show how galaxies evolved from 10 billion years ago to today. While nearby galaxies are fully mature and are at the tail end of their star-formation histories, distant galaxies tell us about the universe's formative years. The light from those early events is just now arriving at Earth. Very distant galaxies are not only faint but also appear small on the sky. Astronomers would like to see how star formation progressed deep within these galaxies. Such details would be beyond the reach of Hubble's vision were it not for the magnification made possible by gravity in the intervening lens region.

In 2006 a team of astronomers using the Very Large Telescope in Chile measured the arc's distance and calculated that the galaxy appears more than three times brighter than previously discovered lensed galaxies. In 2011 astronomers used Hubble to image and analyze the lensed galaxy with the observatory's Wide Field Camera 3.

This illustration shows how an image of a background galaxy is distorted and magnified by the gravitational field of a foreground galaxy. In this alignment gravity acts as a lens in space by warping space like a funhouse mirror. The image of a distant galaxy is stretched into a giant arc.
 
Credit: NASA, ESA, and A. Feild (STScI)

The distorted image of the galaxy is repeated several times in the foreground lensing cluster, as is typical of gravitational lenses. The challenge for astronomers was to reconstruct what the galaxy really looked like, were it not distorted by the cluster's funhouse-mirror effect.

Hubble's sharp vision allowed astronomers to remove the distortions and reconstruct the galaxy image as it would normally look. The reconstruction revealed regions of star formation glowing like bright Christmas tree bulbs. These are much brighter than any star-formation region in our Milky Way galaxy.

Credit: NASA, ESA, J. Rigby (NASA Goddard Space Flight Center), and K. Sharon (Kavli Institute for Cosmological Physics, University of Chicago), and M. Gladders and E. Wuyts (University of Chicago)

Through spectroscopy, the spreading out of the light into its constituent colors, the team plans to analyze these star-forming regions from the inside out to better understand why they are forming so many stars.

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Md., conducts Hubble science operations. STScI is operated by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

For images and more information about galaxy RCS2 032727-132623 and gravitational lensing, visit:
http://hubblesite.org/news/2012/08


Contacts and sources:
NASA

365 New Species Discovered In Peruvian Park

The Wildlife Conservation Society's (WCS) Peru program announced today the discovery of 365 species previously undocumented in Bahuaja Sonene National Park (BSNP) in southeastern Peru.

Fifteen researchers participated in the inventory focusing on plant life, insects, birds, mammals, and reptiles. The discovery included: thirty undocumented bird species, including the black-and-white hawk eagle, Wilson's phalarope, and ash colored cuckoo; two undocumented mammals – Niceforo's big-eared bat and the Tricolored Bat; as well as 233 undocumented species of butterflies and moths. This expedition was especially important because it was the first time that research of this scale has been carried out in Bahuaja Sonene National Park since it was created in 1996.

Giant leaf frogs are among the 50 reptiles and amphibian species found in the park.

 

Credit: Andre Baertschi

"The discovery of even more species in this park underscores the importance of ongoing conservation work in this region," said Dr. Julie Kunen, WCS Director of Latin America and Caribbean Programs. "This park is truly one of the crown jewels of Latin America's impressive network of protected areas."

BSNP contains more than 600 bird species including seven different types of macaw, more than 180 mammal species, more than 50 reptiles and amphibian species, 180 fish varieties, and 1,300 types of butterfly.

Since the 1990s, the Wildlife Conservation Society has been working in Tambopata and Bahuaja Sonene Parks in Peru, and Madidi, Pilon Lajas, and Apolobamba Parks in neighboring Bolivia. The tranboundary region, known as the Greater Madidi Landscape, spans more than 15,000 square miles of the tropical Andes and is considered to be the most biodiverse region on earth.

WCS has helped form more than 20 community-based enterprises in the area that promote the sustainable use of natural resources, such as native honey, subsistence hunting and fishing, ornamental fish cultivation, cacao, handicrafts, and timber. More than 3,000 local people benefit from these community initiatives.


Contacts and sources:
Stephen Sautner
Wildlife Conservation Society

Castaway Lizards Offer New Look at Evolutionary Processes

Differences caused by 'founder effect' persist when populations adapt to new environments.

Biologists who released lizards on tiny uninhabited islands in the Bahamas have uncovered a seldom-observed interaction between evolutionary processes.

A male brown anole lizard (Anolis sagrei) displays its eye-catching dewlap.

 

Credit: Neil Losin

Jason Kolbe, a biologist at the University of Rhode Island (URI)--along with colleagues at Duke University, Harvard University and the University of California, Davis--found that the lizards' genetic and morphological (form and structural) traits were determined by both natural selection and a phenomenon called the founder effect.

Their research results are published online today in the journalScience.

The founder effect is the loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population. It often results in the new population becoming genetically or morphologically different from the original population.

"We rarely observe the founder effect as it happens in nature, but we know that it occurs because islands are colonized by new species over time," said Kolbe.

Tall and broad vegetation typical of the source population island on Iron Cay is shown.

 

Credit: Jason Kolbe

"What we didn't know was how these evolutionary mechanisms [natural selection and the founder effect] interact with each other."

The scientists learned that differences caused by the founder effect persist even as populations adapt to new environments.

Short, narrow vegetation indicative of the founder islands in the study is shown.

 

Credit: Jason Kolbe

"Evolutionary biologists have been debating the importance of founder effects for more than 70 years," said Sam Scheiner, program director in the National Science Foundation (NSF)'s Division of Environmental Biology, which funded the research. "This study is the first to definitively demonstrate those effects for ecologically important traits."

Kolbe and colleagues randomly collected brown anole lizards from a large island near Great Abaco in the Bahamas, and released one pair on each of seven nearby islands whose lizard populations had been cleared by a recent hurricane.

The source island is forested, while the other islands have short, scrubby vegetation.

Previous research had found that anole lizards living in forests had longer hind limbs than those found in scrub habitat.

Lizards with longer limbs can run faster on the broad perches available in forests, while short-limbed lizards are more adept at moving on the narrower perches found in lower vegetation.

The scientists revisited each of the islands over the next four years to measure the lizards' limb length and collect tissue samples for genetic analysis.

Scientists search for lizards on one of the experimental founder islands.

Credit: Jason Kolbe

All the new populations survived and increased an average of 13-fold in the first two years, before leveling off.

"We noticed a founder effect one year after starting the experiment, which resulted in differences among the lizards on the seven islands," Kolbe said.

"Some of the islands had lizards with longer limbs and some had lizards with shorter limbs, but that was random with respect to the vegetation on the new islands."

Because the structure of the vegetation on the islands differed from that of the source island, the scientists predicted that natural selection would lead the lizards to develop shorter limbs.

"Over the next four years, the lizards on all the islands experienced a decrease in leg length that is attributable to natural selection," Kolbe explained. "But those that started out with the longest hind limbs still had the longest hind limbs."

The fact that the populations maintained their order from longest to shortest limbs throughout the experiment means that both the founder effect and natural selection contributed to their current differences.

According to Kolbe, the founder effect is rarely observed in nature, with most previous research conducted in the laboratory.

"Ours is the first to study this process experimentally in a natural setting, and we were able to account for multiple evolutionary mechanisms through time," he said. "We manipulated the founding of these islands, but everything else about it was natural."

The next step in the research will be to determine how long the founder effect persists before other factors erase its signature.

Co-authors of the paper are Kolbe; Manuel Leal of Duke University; Thomas Schoener and David Spiller of the University of California, Davis; and Jonathan Losos of URI.

The study was also funded by the National Geographic Society.


Contacts and sources:
National Science Foundation