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Tuesday, January 27, 2015

'Kindness Curriculum' Boosts School Success In Preschoolers

Over the course of 12 weeks, twice a week, the prekindergarten students learned their ABCs. Attention, breath and body, caring practice — clearly not the standard letters of the alphabet.

Rather, these 4- and 5-year-olds in the Madison Metropolitan School District were part of a study assessing a new curriculum meant to promote social, emotional and academic skills, conducted by the University of Wisconsin-Madison Center for Investigating Healthy Minds (CIHM) at the Waisman Center.

Researchers found that kids who had participated in the curriculum earned higher marks in academic performance measures and showed greater improvements in areas that predict future success than kids who had not. The results were recently published in the journal Developmental Psychology.

“This work started a number of years ago when we were looking at ways to possibly help children develop skills for school and academic success, as well as in their role as members of a global community,” says study lead author Lisa Flook, a CIHM scientist. “There was a strong interest in looking at cultivating qualities of compassion and kindness."

While mindfulness-based approaches for children have become popular in recent years, few are backed by rigorous scientific evidence. The research team — graduate research assistant Simon Goldberg; outreach specialist Laura Pinger; and CIHM founder Richard Davidson, the UW-Madison William James and Vilas Professor of Psychology and Psychiatry — set out to change that.

The team developed a curriculum to help children between the ages of 4 and 6 years learn how to be more aware of themselves and others through practices that encourage them to bring mindful attention to present moment experience. These practices, the researchers hypothesized, could enhance the children’s self-regulation skills – such as emotional control and the capacity to pay attention — and influence the positive development of traits like impulse control and kindness.

Past studies show the ability to self-regulate in early childhood predicts better results later in life with health, educational attainment and financial stability. Flook says early childhood is an opportune time to equip children with these skills since their brains are rapidly developing. The skills may also help them cope with future life stress.

“Knowing how critical these skills are at an early age, if there are ways to promote them, it could help set kids on a more positive life trajectory,” says Flook.

Throughout the study period, trained CIHM instructors taught the curriculum in diverse classrooms throughout the Madison area and worked with students through hands-on activities involving movement, music and books. Each lesson provided students and teachers the opportunity to participate in mindfulness practices, including activities focused on compassion and gratitude, and to take note of their experience.

For example, kids were encouraged to think about people who are helpful to them – sometimes those they may not know well, like the bus driver — and to reflect on the role these people play in their lives, Flook says.

Teachers reported one of the kids’ favorite activities was a practice called “Belly Buddies,” in which they listened to music while lying on their backs, a small stone resting on their stomachs. They were asked to notice the sensation of the stone, and to feel it rising and falling as they breathed in and out.

“It’s something that’s so simple and it allows them to experience internal quietness and a sense of calm,” says Flook.

They also each received alphabet bracelets to wear, to help them remember their kindness curriculum ABCs.

The curriculum itself is rooted in long-standing adult mindfulness-based practices but was adapted to the children’s developmental ability.

The researchers measured the impact of the curriculum on sharing by using stickers the kids could choose to give to a variety of others or keep for themselves. They measured the kids’ ability to delay gratification by choosing one small reward to have immediately or waiting to receive a larger treat later.

The team looked at how well kids could switch from one mental task to another in a card sorting activity, where they were first asked to sort by shape, then by color, and finally, a mix of both. That’s a particularly challenging skill for young kids, Flook says.

The research team also assessed the students’ ability to pay attention by measuring how well they identified particularly oriented arrows on a screen despite the presence of other on-screen distractions, and it examined the students’ academic performance in the months following the study.

In addition to improved academics, the 30 students who went through the curriculum showed less selfish behavior over time and greater mental flexibility than the 38 kids in the control group.

Flook cautions that while the study was designed as a randomized control trial, additional, larger studies are needed to demonstrate the curriculum’s true power. However, the results demonstrate its potential.

Ultimately, the researchers would like to see mindfulness-based practices become “woven into” the school day, adapted to students across grade levels, becoming a foundation for how teachers teach and how students approach learning, Flook says.

“I think there’s increasing recognition of how social, emotional and cognitive functioning are intermingled; that kids may have difficulty in school when emotional challenges arise and that impacts learning,” she adds. “Can you imagine how this could shift the climate of our schools, our community, our world, if cultivating these qualities was at the forefront of education?”

Credit: Wikipedia

Watch Richard Davidson discuss this project at the 2015 World Economic Forum Annual Meeting in Davos, Switzerland.

Contacts and sources:
 Kelly April Tyrrell
University of Wisconsin-Madison

Nocturnal Leg Cramps More Common In Summer

Painful nocturnal leg cramps are about twice as common during summer than in winter, found a new study in CMAJ (Canadian Medical Association Journal). Nocturnal leg cramps are involuntary muscle contractions that occur in the calves, soles of the feet, or other muscles in the body during the night or (less commonly) while resting.

Credit: Wikipedia

Because quinine is commonly prescribed to treat leg cramps, researchers looked at the number of new quinine prescriptions for adults over 50 years of age in British Columbia, Canada, from Dec. 1, 2001 to Oct. 31, 2007. There were 31 339 people, of whom 61% were female, who began taking quinine during the 6-year study period. The researchers then looked at the frequency of Google searches from the United States and Australia for leg cramps.

They found that prescriptions for quinine peaked in British Columbia in July as did Google searches for leg cramps. In Australia, where mid-summer is in January, Google Trends data indicated a similar peak for leg cramp searches. There was no observed seasonality for search terms for back pain, kidney stones, migraines, acne or panic attacks.

"Although there are anecdotal reports of pregnancy-associated rest cramps being worse in summer, these findings establish the phenomenon of seasonality in rest cramps in the general population," writes Dr. Scott Garrison, Faculty of Medicine, University of Alberta, Edmonton, and the Centre for Hip Health and Mobility, University of British Columbia, Vancouver, with coauthors.

These findings could have implications for clinical practice.

"In countries where quinine is still in widespread use as prophylaxis for nocturnal leg cramps despite safety warnings (e.g., Canada and the United Kingdom), physicians may choose to counsel patients to take a 'quinine holiday' during the 6 colder months of the year," suggest the authors.

In a related commentary http://www.cmaj.ca/site/press/cmaj150044.pdf, Dr. David Hogan, University of Calgary, writes that quinine sulfate, although widely used in Canada to treat nocturnal leg cramps, is not recommended for routine treatment because of safety concerns. Clinicians should first prescribe a 4-week course of quinine to determine if it works and encourage patients to try stopping the drug periodically to minimize use.

"The merit of a 'quinine holiday' during the colder months, as suggested by Garrison and colleagues, becomes moot if patients are not prescribed the agent in the first place or are periodically advised to try stopping it," he writes.

Contacts and sources:
Kim Barnhardt
Canadian Medical Association Journal

Entanglement On A Chip: Breakthrough Promises Secure Communications And Faster Computers

Unlike Bilbo's magic ring, which entangles human hearts, engineers have created a new micro-ring that entangles individual particles of light, an important first step in a whole host of new technologies.

Entanglement - the instantaneous connection between two particles no matter their distance apart - is one of the most intriguing and promising phenomena in all of physics. Properly harnessed, entangled photons could revolutionize computing, communications, and cyber security. Though readily created in the lab and by comparatively large-scale optoelectronic components, a practical source of entangled photons that can fit onto an ordinary computer chip has been elusive.

Drawing of the silicon ring resonator with its access waveguide. The green wave at the input represents the laser pump, the red and blue wavepackets at the output represent the generated photon pairs, and the infinity symbol linking the two outputs indicates the entanglement between the pair of photons.

Credit: Università degli Studi di Pavia

New research, reported today in The Optical Society's (OSA) new high-impact journal Optica, describes how a team of scientists has developed, for the first time, a microscopic component that is small enough to fit onto a standard silicon chip that can generate a continuous supply of entangled photons.

The new design is based on an established silicon technology known as a micro-ring resonator. These resonators are actually loops that are etched onto silicon wafers that can corral and then reemit particles of light. By tailoring the design of this resonator, the researchers created a novel source of entangled photons that is incredibly small and highly efficient, making it an ideal on-chip component.

"The main advantage of our new source is that it is at the same time small, bright, and silicon based," said Daniele Bajoni, a researcher at the Università degli Studi di Pavia in Italy and co-author on the paper. "The diameter of the ring resonator is a mere 20 microns, which is about one-tenth of the width of a human hair. Previous sources were hundreds of times larger than the one we developed."

From Entanglement to Innovation

Scientists and engineers have long recognized the enormous practical potential of entangled photons. This curious manifestation of quantum physics, which Einstein referred to as "spooky action at a distance," has two important implications in real-world technology.

First, if something acts on one of the entangled photons then the other one will respond to that action instantly, even if it is on the opposite side of a computer chip or even the opposite side of the Galaxy. This behavior could be harnessed to increase the power and speed of computations. The second implication is that the two photons can be considered to be, in some sense, a single entity, which would allow for new communication protocols that are immune to spying.

This seemingly impossible behavior is essential, therefore, for the development of certain next-generation technologies, such as computers that are vastly more powerful than even today's most advanced supercomputers, and secure telecommunications.

Creating Entanglement on a Chip

To bring these new technologies to fruition, however, requires a new class of entangled photon emitters: ones that can be readily incorporated into existing silicon chip technologies. Achieving this goal has been very challenging.

To date, entangled photon emitters - which are principally made from specially designed crystals -- could be scaled down to only a few millimeters in size, which is still many orders of magnitude too large for on-chip applications. In addition, these emitters require a great deal of power, which is a valuable commodity in telecommunications and computing.

To overcome these challenges, the researchers explored the potential of ring resonators as a new source for entangled photons. These well-established optoelectronic components can be easily etched onto a silicon wafer in the same manner that other components on semiconductor chips are fashioned. To "pump," or power, the resonator, a laser beam is directed along an optical fiber to the input side of the sample, and then coupled to the resonator where the photons race around the ring. This creates an ideal environment for the photons to mingle and become entangled.

As photons exited the resonator, the researchers were able to observe that a remarkably high percentage of them exhibited the telltale characteristics of entanglement.

"Our device is capable of emitting light with striking quantum mechanical properties never observed in an integrated source," said Bajoni. "The rate at which the entangled photons are generated is unprecedented for a silicon integrated source, and comparable with that available from bulk crystals that must be pumped by very strong lasers."

Applications and Future Technology

The researchers believe their work is particularly relevant because it demonstrates, for the first time, a quintessential quantum effect, entanglement, in a well-established technology.

"In the last few years, silicon integrated devices have been developed to filter and route light, mainly for telecommunication applications," observed Bajoni. "Our micro-ring resonators can be readily used alongside these devices, moving us toward the ability to fully harness entanglement on a chip." As a result, this research could facilitate the adoption of quantum information technologies, particularly quantum cryptography protocols, which would ensure secure communications in ways that classical cryptography protocols cannot.

According to Bajoni and his colleagues, these protocols have already been demonstrated and tested. What has been missing was a cheap, small, and reliable source of entangled photons capable of propagation in fiber networks, a problem that is apparently solved by their innovation.

Contacts and sources:
The Optical Society

Paper: D. Grassani, S. Azzini, M. Liscidini, M. Galli, M. J. Strain, M. Sorel, J. E. Sipe, and D. Bajoni, "A micrometer-scale integrated silicon source of time-energy entangled photons," Optica, 2, 1, 88-94 (2015)  doi: http://dx.doi.org/10.1364/OPTICA.2.000088

Satellite View Of Developing US Nor'easter, Video

National Weather Service forecasters have been tracking a low pressure area that moved from the Midwest into the Atlantic Ocean today, and is expected to become a strong nor'easter that will bring blizzard conditions to the northeastern U.S. The path of the system was captured in a NASA movie of NOAA's GOES-East satellite imagery.

NOAA's GOES-East satellite captured the center of the developing Nor'easter located off North Carolina's Outer Banks on Jan. 26 in the image from 16:30 UTC (12:30 p.m. EST).
Credit: NASA/NOAA Goes Project

An animation of visible and infrared imagery from NOAA's Geostationary Operational Environmental or GOES satellite captured over the period of January 24 through 26 showed the progression of the developing nor'easter.

The satellite animation began on Jan. 24 when clouds associated with a cold front preceding the low, pushed off the U.S. East coast. The front was followed by a low pressure area that moved from the Midwest to the southeast. That low moved over the Carolinas and exited into the Atlantic Ocean on Jan. 26. NOAA's National Weather Service forecast calls for the low to intensify along the Eastern Seaboard and bring blizzard conditions to the northeastern U.S. on Monday night, January 26 and Tuesday, January 27.

This GOES-East animation shows a cold front push off the U.S. East coast followed by a low pressure area from the Midwest moved southeast and exited the Carolinas into the Atlantic Ocean. That low pressure area is forecast to intensify into a Nor'easter.

Image Credit: NASA/NOAA GOES Project

On Monday, January 26, 2015, the National Weather Service noted: A storm system off the East Coast will continue to strengthen as it develops into a major nor'easter on Monday. As the storm moves up the coast, it is expected to bring snowfall of 1-3 feet or more to many parts of the Northeast through Tuesday evening, including New York City and Boston. Strong, gusty winds will combine with the snow to create blizzard conditions along and near the coast.

Winter storm warnings are in effect for the panhandles of West Virginia and Maryland, much of interior New England down to the northern Mid-Atlantic as well as for Nantucket Island, Massachusetts. Winter weather advisories are in effect for portions of the Ohio Valley, Mid-Atlantic and the southern Appalachians as well as a narrow area across interior New England.

To create the video and imagery, NASA/NOAA's GOES Project located at NASA's Goddard Space Flight Center in Greenbelt, Maryland overlays the cloud data from NOAA's GOES-East satellite on a true-color image of land and ocean created by data from the Moderate Resolution Imaging Spectroradiometer, or MODIS, instrument that flies aboard NASA's Aqua and Terra satellites. Together, these data create the entire animation of the storm and show its movement.

GOES satellites provide the kind of continuous monitoring necessary for intensive data analysis. Geostationary describes an orbit in which a satellite is always in the same position with respect to the rotating Earth. This allows GOES to hover continuously over one position on Earth's surface, appearing stationary. As a result, GOES provide a constant vigil for the atmospheric "triggers" for severe weather conditions such as tornadoes, flash floods, hail storms and hurricanes.

Contacts and sources:
Rob Gutro
NASA Goddard Space Center 


Huge Ring System Dwarfs Saturn's Rings, From Earth They Would Be Brighter And Larger Than A Full Moon If They Surrounded Saturn

Astronomers at the Leiden Observatory, The Netherlands, and the University of Rochester, USA, have discovered that the ring system that they see eclipse the very young Sun-like star J1407 is of enormous proportions, much larger and heavier than the ring system of Saturn. The ring system - the first of its kind to be found outside our solar system - was discovered in 2012 by a team led by Rochester's Eric Mamajek.

Artist's conception of the extrasolar ring system circling the young giant planet or brown dwarf J1407b is shown. The rings are shown eclipsing the young sun-like star J1407, as they would have appeared in early 2007. The best fit model is consistent with a system of at least 30 rings, and there are gaps where satellites ("exomoons") may have already formed.
Credit: Ron Miller

A new analysis of the data, led by Leiden's Matthew Kenworthy, shows that the ring system consists of over 30 rings, each of them tens of millions of kilometers in diameter. Furthermore, they found gaps in the rings, which indicate that satellites ("exomoons") may have formed. The result has been accepted for publication in the Astrophysical Journal.

"The details that we see in the light curve are incredible. The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings," says Kenworthy. "The star is much too far away to observe the rings directly, but we could make a detailed model based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn's rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon."

"This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn's rings are today," said co-author Mamajek, professor of physics and astronomy at the University of Rochester. "You could think of it as kind of a super Saturn."

The astronomers analyzed data from the SuperWASP project - a survey that is designed to detect gas giants that move in front of their parent star. In 2012, Mamajek and colleagues at the University of Rochester reported the discovery of the young star J1407 and the unusual eclipses, and proposed that they were caused by a moon-forming disk around a young giant planet or brown dwarf.

In a third, more recent study also led by Kenworthy, adaptive optics and Doppler spectroscopy were used to estimate the mass of the ringed object. Their conclusions based on these and previous papers on the intriguing system J1407 is that the companion is likely to be a giant planet - not yet seen - with a gigantic ring system responsible for the repeated dimming of J1407's light.

The light curve tells astronomers that the diameter of the ring system is nearly 120 million kilometers, more than two hundred times as large as the rings of Saturn. The ring system likely contains roughly an Earth's worth of mass in light-obscuring dust particles.

Mamajek puts into context how much material is contained in these disks and rings. "If you were to grind up the four large Galilean moons of Jupiter into dust and ice and spread out the material over their orbits in a ring around Jupiter, the ring would be so opaque to light that a distant observer that saw the ring pass in front of the sun would see a very deep, multi-day eclipse," Mamajek says. "In the case of J1407, we see the rings blocking as much as 95 percent of the light of this young Sun-like star for days, so there is a lot of material there that could then form satellites."

In the data the astronomers found at least one clean gap in the ring structure, which is more clearly defined in the new model. "One obvious explanation is that a satellite formed and carved out this gap," says Kenworthy. "The mass of the satellite could be between that of Earth and Mars. The satellite would have an orbital period of approximately two years around J1407b."

Astronomers expect that the rings will become thinner in the next several million years and eventually disappear as satellites form from the material in the disks.

"The planetary science community has theorized for decades that planets like Jupiter and Saturn would have had, at an early stage, disks around them that then led to the formation of satellites," Mamajek explains. "However, until we discovered this object in 2012, no-one had seen such a ring system. This is the first snapshot of satellite formation on million-kilometer scales around a substellar object."

Astronomers estimate that the ringed companion J1407b has an orbital period roughly a decade in length. The mass of J1407b has been difficult to constrain, but it is most likely in the range of about 10 to 40 Jupiter masses.

The researchers encourage amateur astronomers to help monitor J1407, which would help detect the next eclipse of the rings, and constrain the period and mass of the ringed companion. Observations of J1407 can be reported to the American Association of Variable Star Observers (AAVSO). In the meantime the astronomers are searching other photometric surveys looking for eclipses by yet undiscovered ring systems.

Kenworthy adds that finding eclipses from more objects like J1407's companion "is the only feasible way we have of observing the early conditions of satellite formation for the near future. J1407's eclipses will allow us to study the physical and chemical properties of satellite-spawning circumplanetary disks."

Contacts and sources:
Leonor Sierra
 University of Rochester

Monday, January 26, 2015

A First Peek Beneath The Surface Of A Comet

In some of the first research findings to be published from the European Space Agency's Rosetta Mission to the comet 67P/Churyumov-Gerasimenko, scientists including astronomer Peter Schloerb of the University of Massachusetts Amherst report early measurements of the comet's subsurface temperature and production of gas from the surface of its nucleus.

Writing this week in Science, an international team with lead author Samuel Gulkis of the Jet Propulsion Laboratory, Pasadena, describes the first millimeter-wave measurements made from June through September 2014, of the comet's nucleus, subsurface temperature and of water vapor and other molecules in the coma of gas and dust that is beginning to form around the comet as it approaches the Sun.

Writing this week in Science, an international team describes the first millimeter-wave measurements made from June through September 2014, of the comet's nucleus and of water vapor and other molecules in the coma of gas and dust that is beginning to form around the comet as it approaches the Sun.

Credit:  European Space Agency

The researchers used NASA's Microwave Instrument on the Rosetta Orbiter (MIRO), launched as a part of the European Space Agency's Rosetta Mission, to study heat transport in the comet's nucleus along with outgassing and development of the coma as interrelated processes. Data from MIRO's millimeter-wave radio receivers help to map temperature and spectral information during the day, night and across seasons as the comet approached the sun.

Schloerb, a planetary scientist who brings special expertise in radio astronomy and remote sensing to the team, says such measurements and monitoring of the interplay between gas emissions and surface temperature over time by MIRO provides key information that allows scientists to better understand the evolution of the gas and dust that comprise the comet's coma.

Observations of the comet at millimeter wavelengths allow astronomers to measure the temperature beneath the surface of the comet's nucleus and properties of the gases in the coma as well.

"An important contribution is that we're sensing not only the subsurface, we're also looking at the important properties of gases inside the coma. Our instrument puts the two together, providing an integrated look at the important physical processes that make the comet work," the UMass Amherst astronomer says.

Schloerb adds, "That's valuable because we can measure temperature within the surface and then see the gases that are produced directly as the nucleus heats up. The surface and subsurface temperatures vary quite a lot as the comet rotates and changes its orientation towards the sun during its orbit. It will be fun to relate this driving force behind the gaseous emissions and then see how the molecules produced behave in response as the comet moves toward the sun."

"In our initial results, not surprisingly, we found important day-night and seasonal variations in the temperature of the nucleus. It is northern summer now, so the northern latitudes are quite warm, while some southern latitudes are un-illuminated at this time and very cold. We're the only instrument that can make measurements of this un-illuminated part of the comet, so our measurements are completely unique in that area."

Schloerb says the team's observations from Comet P67 show a comet spectrum was not consistent with water vapor coming out the same in all directions. Instead, water vapor flowed out mainly from the illuminated side.

"Right away, by looking at the shape of the spectrum, we knew the emissions were very asymmetrical, with most gas being produced on the dayside where comet was being heated up. This is not a new result, we've known this in a general way for 30 years from ground based observations, but it was sure interesting to see it up close where we can look at the detailed behavior."

Another of the important properties of gases inside the coma, besides composition, is their speed as they escape, Schloerb says. MIRO has the ability to measure the outflow speed of the gasses, which is fundamental to the interpretation of observations of the coma and a key parameter needed to check theoretical models.

The UMass Amherst astronomer, who has studied comets for decades and led the worldwide radio observations of Halley's comet as a part of the International Halley Watch in the 1980s, says, "This has been a pretty neat experience. I've never been on a spacecraft project before, but as a planetary scientist I always wanted to do this. After all those years of sitting and looking through a telescope, to see the spectra come in and make the first maps ever of the comet nucleus is really satisfying."

A component of one of the receivers was built at UMass Amherst by Neal Erickson, a world expert on millimeter and submillimeter receivers.

Contacts and sources:
University of Massachusetts Amherst

H.E.S.S. Finds Three Extremely Luminous Gamma-Ray Sources

Wits scientists are part of a multinational team of astronomers working on the High Energy Stereoscopic System (H.E.S.S.) telescopes that have again demonstrated its excellent capabilities in searching for high-energy gamma rays.

In the latest discovery, H.E.S.S. found three extremely luminous gamma-ray sources in the Large Magellanic Cloud (LMC), a satellite dwarf galaxy of the Milky Way. These are objects of different types, namely the most powerful pulsar wind nebula; the most powerful supernova remnant; and a shell of 270 light years in diameter blown by multiple stars, and supernovae – a so-called superbubble.

The Large Magellanic Cloud (LMC) is ablaze with star-forming regions. From the Tarantula Nebula, the brightest stellar nursery in our cosmic neighborhood, to LHA 120-N 11, part of which is featured in this Hubble image, the small and irregular galaxy is scattered with glowing nebulae, the most noticeable sign that new stars are being born.
Image Credit: ESA/NASA/Hubble

The discovery is announced in the latest edition of the scientific journal, Science, in a research paper titled: The exceptionally powerful TeV ƴ-ray emitters in the Large Magellanic Cloud, which will be published on Friday, 23 January 2015.

“This is a very important breakthrough for the team,” says Professor Sergio Colafrancesco, DST/NRF SKA Research Chair in the Wits School of Physics. “It paves the way to study external galaxies with very high-E telescopes such as H.E.S.S and then later with the planned Cherenkov Telescope Array (CTA) in Namibia. It will lead us to re-examine galaxy evolution and answer questions such as how high-E particles can affect the evolution of cosmic structures in the universe, principally galaxies, and the life cycles of matter in galaxies,” he adds.

Very high-energy gamma rays are the best tracers of cosmic accelerators such as supernova remnants and pulsar wind nebulae – end-products of massive stars. There, charged particles are accelerated to extreme velocities. When these particles encounter light or gas in and around the cosmic accelerators, they emit gamma rays. Very high-energy gamma rays can be measured on Earth by observing the Cherenkov light emitted from the particle showers produced by incident gamma
rays high up in the atmosphere using large telescopes with fast cameras.

The Large Magellanic Cloud (LMC) is a dwarf satellite galaxy of our Milky Way, located about 170.000 light years away and showing us its face. New, massive stars are formed at a high rate in the LMC, and it harbors numerous massive stellar clusters. The LMC’s supernova rate relative to its stellar mass is five times that of our Galaxy. The youngest supernova remnant in the local group of galaxies, SN 1987A, is also a member of the LMC. Therefore, the H.E.S.S. scientists dedicated significant observation to searching for very high-energy gamma rays from this cosmic object.

SN 1987A
Credit: NASA

For a total of 210 hours, H.E.S.S. has observed the largest star-forming region within the LMC called Tarantula Nebula. For the first time in a galaxy outside the Milky Way, individual sources of very high-energy gamma rays could be resolved: three extremely energetic objects of different type.

The so-called superbubble 30 Dor C is the largest known X-ray-emitting shell and appears to have been created by several supernovae and strong stellar winds. Superbubbles are broadly discussed as (complementary or alternative to individual supernova remnants) factories where the galactic cosmic rays are produced. The H.E.S.S. results demonstrate that the bubble is a source of, and filled by, highly energetic particles. The superbubble represents a new class of sources in the very high-energy regime.

Superbubble 30 Dor C 
Credit: Chandra X-ray Observatory

Pulsars are highly magnetized, fast rotating neutron stars that emit a wind of ultra-relativistic particles forming a nebula. The most famous one is the Crab Nebula, one of the brightest sources in the high-energy gamma-ray sky. The pulsar PSR J0537−6910 driving the wind nebula N 157B discovered by the H.E.S.S. telescopes in the LMC is in many respects a twin of the very powerful Crab pulsar in our own Galaxy. However, its pulsar wind nebula N 157B outshines the Crab Nebula by an order of magnitude, in very high-energy gamma rays. Reasons are the lower magnetic field in N 157B and the intense starlight from neighboring star-forming regions, which both promote the generation of high-energy gamma rays.

The supernova remnant N 132D, known as a bright object in the radio and infrared bands, appears to be one of the oldest – and strongest – supernova remnants still glowing in very high-energy gamma rays. Between 2500 and 6000 years old – an age where models predict that the supernova explosion front has slowed down and it ought no longer to be efficiently accelerating particles – it still outshines the strongest supernova remnants in our Galaxy. The observations confirm suspicions raised by other H.E.S.S. observations, that supernova remnants can be much more luminous than thought before.

N 132D
Credit: Chandra X-ray Observatory

Observed at the limits of detectability, and partially overlapping with each other, these new sources challenged the H.E.S.S. scientists. The discoveries were only possible due to the development of advanced methods of interpreting the Cherenkov images captured by the telescopes, improving in particular the precision with which gamma-ray directions can be determined.

Indeed, the new H.E.S.S. II 28 m telescope will boost the performance of the H.E.S.S. telescope system, and in the more distant future the planned Cherenkov Telescope Array (CTA) will provide even deeper and higher-resolution gamma-ray images of the LMC – in the plans for science with CTA, the satellite galaxy is already identified as a “Key Science Project” deserving special attention.
The H.E.S.S. telescope is operated by an international collaboration of scientists with a strong involvement by South African universities, in particular Wits University, North West University, and the Universities of the Free State and Johannesburg.

Wits physicists are particularly involved in data analysis techniques, the development of theoretical interpretation tools of both extragalactic and galactic sources, and in the operational shifts at the telescope location in Namibia.

Contacts and sources:
University of the Witwatersrand (Wits)

Yes, Black Holes Exist In Gravitational Theories With Unbounded Speeds Of Propagation!

Lorentz invariance (LI) is a cornerstone of modern physics, and strongly supported by observations.

In fact, all the experiments carried out so far are consistent with it, and no evidence to show that such a symmetry needs to be broken at a certain energy scale. Nevertheless, there are various reasons to construct gravitational theories with broken LI. In particular, our understanding of space-times at Plank scale is still highly limited, and the renomalizability and unitarity of gravity often lead to the violation of LI.

The foliation of the timelike hypersurfaces on which the khronon phi becomes a constant, and the location of the universal horizon xi = xi_{UH}. The khronon defines globally an absolute time, and the trajectory of a particle is always along the increasing direction of phi. Thus, once it cross the horizon, the particle move toward the singularity r = 0 and reaches it within a finite proper time.

Credit: Anzhong Wang and the paper can be found in the International Journal of Modern Physics D, via the following link,http://www.worldscientific.com/doi/abs/10.1142/S0218271814430044

One concrete example is the Horava theory of quantum gravity, in which the LI is broken in the ultraviolet (UV), and the theory can include higher-dimensional spatial derivative operators, so that the UV behavior is dramatically improved and can be made (power-counting) renormalizable.

On the other hand, the exclusion of high-dimensional time derivative operators prevents the ghost instability, whereby the unitarity of the theory -- a problem that has been faced since 1977 [ K.S. Stelle, Phys. Rev. D16, 953 (1977)] -- is assured. In the infrared (IR) the lower dimensional operators take over, whereby a healthy low-energy limit is presumably resulted.

However, once LI is broken different species of particles can travel with different velocities, and in certain theories , such as the Horava theory mentioned above, they can be even arbitrarily large. This suggests that black holes may not exist at all in such theories, as any signal initially trapped inside a horizon can penetrate it and propagate to infinity, as long as the signal has sufficiently large velocity (or energy). This seems in a sharp conflict with current observations, which strongly suggest that black holes exist in our universe [R. Narayan and J.E. MacClintock, Mon. Not. R. Astron. Soc., 419, L69 (2012)].

A potential breakthrough was made recently by Blas and Sibiryakov [D. Blas and S. Sibiryakov,Phys. Rev. D84, 124043 (2011)], who found that there still exist absolute causal boundaries, the so-called universal horizons, and particles even with infinitely large velocities would just move around on these boundaries and cannot escape to infinity.

This has immediately attracted lot of attention. In particular, it was shown that the universal horizon radiates like a blackbody at a fixed temperature, and obeys the first law of black hole mechanics [P. Berglund, J. Bhattacharyya, and D. Mattingly, Phys. Rev. D85, 124019 (2012);Phys. Rev. Lett. 110, 071301 (2013)]. The main idea is as follows: In a given space-time, a globally timelike foliation parametrized by a scalar field, the so-called khronon, might exist.

Then, there is a surface at which the khronon diverges, while physically nothing singular happens there, including the metric and the space-time. Given that the khronon defines an absolute time, any object crossing this surface from the interior would necessarily also move back in absolute time, which is something forbidden by the definition of the causality of the theory. Thus, even particles with superluminal velocities cannot penetrate this surface, once they are trapped inside it.

In all studies of universal horizons carried out so far the khronon is part of the gravitational theory involved. To generalize the conception of the universal horizons to any gravitational theory with broken LI, recently Lin, Abdalla, Cai and Wang promoted the khronon to a test field, a similar role played by a Killing vector, so its existence does not affect the given space-time, but defines the properties of it.

By this way, such a field is no longer part of the underlaid gravitational theory and it may or may not exist in a given space-time, depending on the properties of the space-time considered. Then, they showed that the universal horizons indeed exist, by constructing concrete static charged solutions of the Horava gravity. More important, they showed that such horizons exist not only in the IR limit of the theory, as has been considered so far in the literature, but also in the full Horava theory of gravity, that is, when high-order operators are not negligible.

Contacts and sources:
 World Scientific

This work was supported in part by DOE, DE-FG02-10ER41692, USA (AW); Ciencia Sem Fronteiras, No. A045/2013 CAPES, Brazil (AW); NSFC No. 11375153, China (AW); FAPESP No. 2012/08934-0, Brazil (EA, KL); CNPq, Brazil (EA, KL); and NSFC No.10821504, China (RC), No.11035008, China (RC), and No.11375247, China (RC). The opinions expressed in this publication are those of the authors and do not necessarily reflect the views of any of these foundations.

The corresponding author of this paper is Anzhong Wang, anzhong_wang@baylor.edu, and the paper can be found in the International Journal of Modern Physics D, via the following link,http://www.worldscientific.com/doi/abs/10.1142/S0218271814430044. Access the PDF directly from http://www.worldscientific.com/doi/pdf/10.1142/S0218271814430044.

Study Projects Unprecedented Loss Of Corals In Great Barrier Reef Due To Warming

The coverage of living corals on Australia's Great Barrier Reef could decline to less than 10 percent if ocean warming continues, according to a new study that explores the short- and long-term consequences of environmental changes to the reef.

Environmental change has caused the loss of more than half the world's reef building corals. Coral cover, a measure of the percentage of the seafloor covered by living coral, is now just 10-20 percent worldwide. The Great Barrier Reef, once thought to be one of the more pristine global reef systems, has lost half of its coral cover in only the last 27 years.

The coverage of living corals on Australia's Great Barrier Reef could decline to less than 10 percent if ocean warming continues, according to a new study.

Credit:  Catlin Seaview Survey/Underwater Earth

Overfishing, coastal pollution and increased greenhouse gas emissions leading to increased temperatures and ocean acidification, as well as other human impacts are all affecting the delicate balance maintained in coral reef ecosystems.

Now, in a new study that aims to project the composition of the future Great Barrier Reef under current and future environmental scenarios, researchers found that in the long term, moderate warming of 1-2 degrees Celsius would result in a high probability of coral cover declining to less than 10 percent, a number thought to be important for maintaining reef growth.

In the short term, with increasing temperatures as well as local man-made threats like coastal development, pollution, and over-fishing, the study found that corals--tiny animals related to jellyfish--would be over-run by seaweed which would, in effect, suffocate them. In the longer term, interactions among reef organisms would lead to dominance by other groups, including sponges and soft corals known as gorgonians.

The study, now in pre-print online in the journal Ecology, uses a multivariate statistical model and includes quantitative surveys of 46 reef habitats over 10 years of data from 1996-2006.

"The model indicated that warming of an additional 1-2 degrees Celsius would more than likely lead large declines in coral cover and overall changes to the community structure," said lead author Jennifer K. Cooper, a graduate student in marine biology at James Cook University. "If our model is correct the Great Barrier Reef will begin to look very different as ocean temperatures increase."

Cooper was part of an international team of ecologists who conducted the study at the National Institute for Mathematical and Biological Synthesis (NIMBioS).

"Even the massive, remote, and intensely managed Great Barrier Reef is being degraded by human activities. Losing the GBR and other reefs would be a massive blow to marine biodiversity and to the people that depend on healthy reefs for food, tourism, and protection from storms," said co-author John Bruno, a marine ecologist from the University of North Carolina, Chapel Hill.

The Great Barrier Reef, which stretches along most of the coastline of the state of Queensland and is about the size of Japan, contains the world's largest collection of coral reefs, with 400 types of coral, 1,500 species of fish and 4,000 types of mollusks. The United Nations listed the reef as a World Heritage site in 1981, but is being considered this year to be placed on the List of World Heritage in Danger.

The study matches similar dynamics found in a recent study widely reported in the media, which said that some parts of the Great Barrier Reef can recover in the short term from damage due to global warming. Yet, the longer term future is bleak for the coral reefs in spite of any short-term recovery.

Co-author Matthew Spencer, who conducted the study while a sabbatical visitor at NIMBioS, said that the findings are not only important for predicting reef futures under climate change but could also be applied to other ecosystems. "The beauty of this study is that the same approach should work for other systems, provided enough data are available," he said. "Our next plan is to use it to model the dynamics of European forests."

Contacts and sources:
Jennifer K. Cooper, James Cook University
Matthew Spencer, Univ. of Liverpool
John Bruno, Univ. of North Carolina, Chapel Hill
Catherine Crawley, NIMBioS

Citation: Cooper JK, Spencer M, Bruno JF. 2015. Stochastic dynamics of a warmer Great Barrier Reef. Ecology. [Online Pre-Print] 12 January 2015. http://dx.doi.org/10.1016/j.jtbi.2015.01.002

The National Institute for Mathematical and Biological Synthesis is an NSF-supported center that brings together researchers from around the world to collaborate across disciplinary boundaries to investigate solutions to basic and applied problems in the life sciences.

China Takes Over Lead From Europe In 2013 Photovoltaic Installations

A booming photovoltaic market in Asia has propelled China to a global leader in photovoltaic energy installations in 2013, according to the latest edition of the JRC’s PV Status Report

The EU has retained its domination in cumulative installed capacity – its total of 80.7 GW represents a 57 % share of the world’s 140 GW of solar photovoltaic electricity generation capacity at the end of 2013. However, this is down from a 70% share in 2012, reflecting Europe’s stagnating market.

The report combines up-to-date information on photovoltaics in 2013, collected from public and commercial studies and own research. It finds that despite an overall drop in solar energy investments – amounting to 23% compared to 2012 – the falling prices for photovoltaic cells and modules have allowed for a 23% increase in the annual installation capacity with respect to the previous year. 

The photovoltaic industry has changed dramatically over the last few years, with markets shifting due to a greater demand in Asia: from the total of 39.5 GW of new installations in 2013, 12.9 GW were set up in China and 7 GW in Japan. For a first time China has left behind the EU (10.6 GW), which has dominated the market in the past decade.

Annual PV installations from 2005 to 2014 

 (data source: [Epi 2014, Eur 2014], JRC analysis)

Since 2005, solar photovoltaic electricity generation capacity in the EU has increased from 1.9 GW to 80.7 GW at the end of 2013. It can cover 2.9% of EU’s electricity demand, or the electricity needs of Belgium or Finland. But EU’s share globally is declining both in relation to the growing market worldwide and in actual installation figures. 

Its share in cumulative capacity, amounting to 70% in 2012 and 57.6% in 2013, is projected to fall below 30% by 2020, according to a forecast by the International Energy Agency (Medium-Term Renewable Energy Market Report 2014) due to a shrinking market. Such development is partly a result of supporting schemes in some member states which missed to adequately address the very rapidly growing market. 

The biggest drop in photovoltaic installations was recorded in Germany (from 7.5 GW in 2011 and 7.6 GW in 2012 to 3.3 installed GW in 2013) and in Italy, where it was more than halved compared to the new installations in each of the previous three years.

Contacts and sources:
European Commission Research & Innovation

Transforming The Driving Experience: The Connected Car

Just as the internet revolutionized the way we use mobile devices, the 'connected car' has the opportunity to transform the driving experience. CARMESH, a European Union (EU)-funded Marie Curie project, took the first steps towards a seamless integration of digital life into the car.

© Syda Productions - fotolia

For four years, the CARMESH team investigated architectures and systems such as Wireless Mesh Networks (WMNs), suitable for the connected car. The researchers developed a prototype system for high-speed mobile connectivity while driving.

Once on the market, the CARMESH system, which is a mobile phone application that works with the car's network interface, is expected to increase safety standards by providing regular updates such as road conditions and diversions to the user. Moreover, the overall driving experience around metropolitan areas could be improved through constant location-based traffic updates to help drivers avoid lengthy traffic jams.

The research team’s vision was centered on the hands-free mobile phone, which is integrated with the wireless network interface in the car. Mobile phone applications connect wirelessly to the vehicle and are designed to avoid driver distraction – in fact, only pertinent information is relayed to the driver while on the road.

“Social networking, mapping and event services could all be tailored to the car,” says project coordinator Dr. John Murphy of University College Dublin in Ireland. “The system developed by the project team is also expected to gather data on the driving behavior and inform users if there are any car maintenance issues to address,” he adds.

Both the academic and the industrial partners working on the CARMESH project learned a great deal about how to deliver high-quality service and networking to the ‘connected car’. Due to their work and presence at numerous events, such as the Automotive Linux Summit in Edinburgh in 2013, the researchers also increased their collaboration with the automotive sector. Experts predict that by 2025, 60% of all cars will have extended internet connectivity. And, with the automotive industry seeing the ‘connected car’ market as an opportunity.

Contacts and sources:
European Commission Research & Innovation

Personalized Travel Advice From Your Pocket

While many of us are used to checking transport schedules on our smartphones, the i-TOUR app, created by EU-funded researchers, goes much further. It advises which form of transport is most appropriate to get from A to B in large urban areas wherever you are in Europe, and takes into account personal preferences, weather and changing circumstances. The i-TOUR team is currently discussing how to take the idea to the market.

Credit: © Halfpoint - fotolia

The rationale behind i-TOUR was to give every smartphone or tablet owner the means to have as smooth a journey as possible, particularly when in large urban areas, explains project coordinator Piero Trucco of Formit Servizi in Italy.

What makes i-TOUR different from all the other apps offering travel information is its ability to scan all transport modes before offering advice. While most apps require the user to select bus, car or bike, for example, i-TOUR makes that decision for the user – or at least advises on the most appropriate mode.

Arriving late for an appointment should also be a thing of the past for i-TOUR app users. If an accident delays the tram or a commuter bumps into a friend on the way to the station, i-TOUR can re-schedule while the traveller is still on the move.

Personalised route-planner

It is this ability to scan both public and private transport networks before advising on the best route that helps i-TOUR stand out from the crowd of navigation apps. “The app does not choose, a priori, one means of transportation. It does not ideologically favour public transport. It proposes the fastest and most economical way to get from A to B at a particular time of day,” says Trucco.

All forms of public transportation are also treated equally in view of the ultimate interest of the passenger, emphasises Trucco. The technology behind this involves an interface that is able to plug into different transport databases – from that of Rome’s bus company to those of the city’s car share and metro systems.

Each database is of course organised differently, which was a technological challenge for the project team. The solution is an open source system that gives each public transport operator responsibility for creating, maintaining and updating its service.

Each company’s local area network (LAN) can interface with the i-TOUR system, and a multimodal routing system then harmonises the structure and format of the data received from different companies so that it can be displayed on i-TOUR.

The ability to plug into individual transport systems “is, I think, from a technological standpoint, the app’s best feature,” says Trucco.

From prototype to market

The project’s study of privacy issues is “state-of-the-art” according to Trucco, and could be used for other apps. He believes that privacy is often neglected by app developers. The study results have been shared with the European Telecommunications Standards Institute (ETSI), and have contributed to standardisation for security, particularly for navigation apps.

The i-TOUR team has a working prototype, and discussions have been underway on taking the app to the market since the project finished in July 2013. The remaining challenges are not technical but contractual, relating to licencing and privacy.

The business plan foresees two likely possibilities: the creation of a new company, or partnership with a technology company. Either way, the team has “a viable business case, and with a relatively small investment will be able to take the app to the market,” says Trucco.

Contacts and sources:
European Commission Research & Innovation

Spray The Rats Away - Better Ways To Rid Us Of Rodents

Rats damage crops, buildings and infrastructure, costing billions of euros every year. They also carry more than 60 diseases that threaten humans and animals. But now scientists in Britain are using smart electronics to counter the danger.

Professor of Chemistry Michael Tisdale knows the rodent problem well. He has a small holding near Birmingham in central England where he keeps chickens. It has been invaded by rats who gnaw through anything to steal food from his animals.

Professor of Chemistry Michael Tisdale

Professor Tisdale, who works at Birmingham's Aston University, told euronews the rodents are keen to get to the food he puts out for the chickens: “The rats come out in the night, they dig a hole, they get under the door, get inside, and they eat the food.”

Like everyone, he uses poisonous pellets, but ordinary poisons don’t seem to help anymore. Professor Tisdale says the rats seem to enjoy some common toxins as free food: “The place is literally alive with them at night, even though we put poison down. They do eat the poison, but they seem to become resistant to it. That’s the main problem.”

At Aston University they are working as part of a European research project called Piedpiper.

It takes a different approach: rather than waiting for the rat to eat enough poison to die, the new system sprays the rodent with a single deadly dose of toxin.

Drug delivery researcher Andrew Ingham is working on the project: “This is one of the first commercial systems that will spray rats, and actually kill them through absorbing the toxin through their skin.”

Scientists have created a vitamin D-based formula. It is safe for common animals but deadly for rats who can’t metabolise it.

Experiments are being carried out to show how fast the toxin gets into a rat’s blood after it is sprayed.

Andrew Ingham explains: “We perform all experiments in glassware in the laboratory to a model membrane that represents rat skin. Once we’ve optimised all the different formulations, we can then select out the best way of transferring vitamin across the skin.”

To deliver the toxin, researchers have made an electronic device that uses light sensors to that when a rat runs through it the poisonous spray is triggered at exactly the right moment. A pheromone inside the device attracts rats in.

The system detects when the rat gets right under the spray can. It is not triggered if the animal that enters is not a rat, or if two rats try to enter the device from both ends at the same time.

Aston University Biomedical engineer Joseph Davies says the system can also be remotely monitored to make sure the poison is quickly replaced when it is all used up: “There’s a microprocessor on the circuit board. It gives an option for the device to send a signal or a message to the pest control officer to tell them to come and replace the can.”

The current traps, known as multi-feed stations, use poison pellets and kill rats slowly and painfully by causing internal bleeding. The new device is more humane as the rats die of a heart attack one day after being sprayed.

Drug delivery researcher Andrew Ingham says their product is more effective: “The multi-feed station means that animal can chose how much he wants to eat, and often doesn’t eat enough to kill him. Our prototype system has a single-shot formulation which means it’s guaranteed death once it’s been sprayed.”

Sunday, January 25, 2015

A 3-D View Of The Greenland Ice Sheet Opens Window On Ice History

Scientists using ice-penetrating radar data collected by NASA’s Operation IceBridge and earlier airborne campaigns have built the first comprehensive map of layers deep inside the Greenland Ice Sheet, opening a window on past climate conditions and the ice sheet’s potentially perilous future.

Peering into the thousands of frozen layers inside Greenland’s ice sheet is like looking back in time. Each layer provides a record of not only snowfall and melting events, but what the Earth’s climate was like at the dawn of civilization, or during the last ice age, or during an ancient period of warmth similar to the one we are experiencing today. Using radar data from NASA’s Operation IceBridge, scientists have built the first-ever comprehensive map of the layers deep inside the ice sheet.
Credit: NASA

This new map allows scientists to determine the age of large swaths of the second largest mass of ice on Earth, an area containing enough water to raise ocean levels by about 20 feet.

“This new, huge data volume records how the ice sheet evolved and how it’s flowing today,” said Joe MacGregor, the study’s lead author, a glaciologist at The University of Texas at Austin Institute for Geophysics (UTIG), a unit of the Jackson School of Geosciences.

Credit:  University of Texas at Austin

Greenland’s ice sheet has been losing mass during the past two decades, a phenomenon accelerated by warming temperatures. Scientists are studying ice from different climate periods in the past to better understand how the ice sheet might respond in the future.

Ice cores offer one way of studying the distant past. These cylinders of ice drilled from the ice sheet hold evidence of past snow accumulation and temperature and contain impurities such as dust and volcanic ash compacted over hundreds of thousands of years. These layers are visible in ice cores and can be detected with ice-penetrating radar.

Ice-penetrating radar works by sending radar signals into the ice and recording the strength and return time of reflected signals. From those signals, scientists can detect the ice surface, sub-ice bedrock and layers within the ice.

New techniques used in this study allowed scientists to efficiently pick out these layers in radar data. Prior studies had mapped internal layers, but not at the scale made possible by these newer, faster methods.

Another major factor in this study was the scope of Operation IceBridge’s measurements across Greenland, which included flights that covered distances of tens of thousands of kilometers across the ice sheet.

“IceBridge surveyed previously unexplored parts of the Greenland Ice Sheet and did it using state-of-the-art CReSIS radars,” said study co-author Mark Fahnestock, an IceBridge science team member and glaciologist from the Geophysical Institute at the University of Alaska Fairbanks (UAF-GI).

CReSIS is the Center for Remote Sensing of Ice Sheets, a National Science Foundation science and technology center headquartered at the University of Kansas in Lawrence, Kansas.

IceBridge’s flight lines often intersect ice core sites where other scientists have analyzed the ice’s chemical composition to map and date layers in the ice. These core data provide a reference for radar measurements and provide a way to calculate how much ice from a given climate period exists across the ice sheet, something known as an age volume. Scientists are interested in knowing more about ice from the Eemian period, a time from 115,000 to 130,000 years ago that was about as warm as today. This new age volume provides the first data-driven estimate of where Eemian ice may remain.

Researchers have developed 3-D maps of the age of the ice within the Greenland Ice Sheet. The new research will help scientists determine what may happen to the ice sheet as the climate changes.

Credit:  University of Texas at Austin

Comparing this age volume to simple computer models helped the study’s team better understand the ice sheet’s history. Differences in the mapped and modeled age volumes point to past changes in ice flow or processes such as melting at the ice sheet’s base. This information will be helpful for evaluating the more sophisticated ice sheet models that are crucial for projecting Greenland’s future contribution to sea-level rise.

“Prior to this study, a good ice-sheet model was one that got its present thickness and surface speed right. Now, they’ll also be able to work on getting its history right, which is important because ice sheets have very long memories,” said MacGregor.

Contacts and sources: 
University of  Texas - Austin

This study was published online on Jan. 16, 2015, in Journal of Geophysical Research: Earth Surface. It was a collaboration among scientists at UTIG, UAF-GI, CReSIS and the Department of Earth System Science at the University of California, Irvine. It was supported by NASA’s Operation IceBridge and the National Science Foundation’s Arctic Natural Sciences.

For more information on Operation IceBridge, visit: www.nasa.gov/icebridge.

150 Kilometer Diamerter Crater In Nevada Results From Bolide Impact On Ancient Seafloor

Carbonate rock deposits found within the mountain ranges of south-central Nevada, USA, record evidence of a catastrophic impact event known as the Alamo impact. This event occurred roughly 382 million years ago when the ancient seafloor was struck and a submarine crater was formed. The crater was filled-in with fragmented rock, and later with more typical ocean deposits, as the energy from the impact lessened and the environment returned to normal. 

By studying the distribution and features of the post-impact ocean deposits and fragmented rock that filled the crater, Andrew J. Retzler of Idaho State University and colleagues present a new map characterizing the size and shape of the Alamo crater. Their results indicate that only about half of the Alamo impact crater and its related deposits are now exposed within the region, and they estimate its total diameter to be between 111 and 150 km. 

This is more than double previous estimates and, if correct, places the Alamo crater as one of the largest marine impacts in the last 550 million years, conservatively larger than the well-studied Chesapeake Bay impact crater (about 35 million years old) on the eastern shore of North America.

Landscape showing Alamo impact breccia (arrow) near Hancock Summit, Pahranagat Range, Nevada

To date, there are only 182 confirmed impact structures on Earth (see the Earth Impact Database). In contrast, most other planets consist of thousands to hundreds of thousands of impact structures. Regardless, Earth has undergone billions of years of bolide impacts, mainly taking place in its early history (about 3.8 to 4 billion years ago). Evidence of these early bolide impacts has been erased due to the dynamic nature of the Earth over millions of years. The thick atmosphere, deep oceans, and mobile crust unique to our planet has altered bolides and hidden their structures!

Only a handful of Earth's impact structures are relatively undeformed (for example: Manson, Mjølnir, Lockne, Popigai, and Ries craters), allowing geologists to better study bolide impact processes and their effects on Earth's systems. Most of these craters are exposed on the surface, which are more accessible than submarine impacts, such as the Mjølnir crater. Few submarine impact structures are known, and they are largely understudied due to the deep ocean depths in which they exist.

Lockne Crater in Sweden

The relatively young age of the oceanic crust also worsens the chance of submarine impact preservation. Oceanic crust is continually being created at ocean spreading ridges, where molten rock flows out and cools to form new oceanic crust. As the ocean floor spreads apart, older oceanic crust is pushed away and subducted underneath the continental plates, where it is melted and recycled beneath Earth's crust. Thus, any impacts that may have occurred on the ocean floor deep in Earth's history may have been subducted, re-melted, and recycled to create new oceanic crust.

The Alamo Impact Event represents a submarine impact that has since been exposed onto land. Such exposures allow geologists to better study and understand submarine impact processes, making the Alamo Impact an excellent case study. Other submarine impact structures that are now exposed on land include: the Chesapeake Bay (85-km diameter), the Montagnais (45-km diameter), the Mjølnir (40-km diameter), and the Ust Kara (25-km diameter) craters.

Contacts and sources:
Geological Society of America

Citation: Post-impact depositional environments as a proxy for crater morphology, Late Devonian Alamo impact, Nevada. Andrew J. Retzler et al., Idaho State University, Pocatello, Idaho, USA. Published online on 14 Jan. 2015; http://dx.doi.org/10.1130/GES00964.1.

Bad Reputation Of Crows Demystified

In literature, crows and ravens are a bad omen and are associated with witches. Most people believe they steal, eat other birds' eggs and reduce the populations of other birds. But a new study, which has brought together over 326 interactions between corvids and their prey, demonstrates that their notoriety is not entirely merited.

Corvids - the bird group that includes crows, ravens and magpies - are the subject of several population control schemes, in both game and conservation environments. These controls are based on the belief that destroying them is good for other birds. They are also considered to be effective predators capable of reducing the populations of their prey.

The 326 interactions between corvids and their prey, shows that they have a much smaller effect on other bird species than was previously thought. 
Credit: Jorge Piñeiro

However, a study published recently in the journal 'Ibis' analysed the impact of six species of corvid on a total of 67 species of bird susceptible to being their prey, among which are game birds and passerine birds.

The project, which compiled the information of 42 scientific studies and analysed a total of 326 interactions between corvids and their prey, shows that they have a much smaller effect on other bird species than was previously thought.

As Beatriz Arroyo - author of the study and a researcher at the Institute of Research in Game Resources (IREC), a joint centre of the University of Castilla-La Mancha, the Castilla-La Mancha Community Council and the CSIC (Spanish National Research Council) - tells SINC: "In 81% of cases studied, corvids did not present a discernible impact on their potential prey. Furthermore, in 6% of cases, some apparently beneficial relationships were even observed."

Greater impact on reproduction

To find out what impact corvids have on their prey, the researchers - in conjunction with the University of Cape Town (South Africa) - conducted several experiments in which they isolated crows, ravens and magpies, among other predators, to observe how they affected the reproduction and abundance of other birds.

According to the works analysed, when crows were taken away from their habitat, the survival rates of chickens and the number of eggs of other species were higher in most cases. Nevertheless, with respect to abundance, without corvids an increased size of the populations of other birds was observed only in a small number of cases.

According to the study, when crows were removed from the environment, in 46% of cases their prey had greater reproductive success, while their abundance fell in less than 10% of cases.

Additionally, these experimental studies carried out in nine different countries (Canada, France, Norway, Poland, Slovakia, Spain, Sweden, the UK and the USA) revealed that, if corvids are eliminated but other predators are not, the impact on the productivity of their prey would be positive in only 16% of cases; whilst without corvids and other predators, including carnivores, the productivity of other birds improves in 60% of cases.

This suggests that crows, ravens and magpies, amongst others, have a lower impact on prey than other threats. "Compensatory predation can also occur," the researcher explains.

In the study they also compared the effects between different groups of corvids. In these results it is striking that "magpies had much less impact on prey than other species," Arroyo claims.

Comparing crows and magpies, the scientists showed that in 62% of cases crows impacted negatively on the reproduction of their prey, whilst magpies had a negative effect in 12% of cases. "But no differences related to the abundance of prey were noted," the scientist affirms.

For the authors of this piece of research, given the results it is necessary to "be cautious" when drawing conclusions on the impact of magpies or crows on the populations of their prey. "This method of managing populations is frequently ineffective and unnecessary," Arroyo finishes.

Contacts and sources:
 Plataforma SINC

Citation:  Madden, C.F., Arroyo, B. & Amar, A. "A review of the impact of corvids on bird productivity and abundance" Ibis 5 December 2014 doi: 10.1111/ibi.12223

Rosetta Reveals Churi's Secrets: Witness To The Birth Of The Solar System And More

With its surprising two-lobed shape and high porosity, the nucleus of comet 67P/Churyumov-Gerasimenko (nicknamed Churi) has a wide range of features, revealed by the MIRO, VIRTIS and OSIRIS instruments of ESA's Rosetta mission, which involves researchers from the CNRS, the Paris Observatory and several universities , with support from CNES.

CO2/H2O ratio of the comet measured by ROSINA from 17 August to 22 September 2014. 

Credit: © ESA/Rosetta/ROSINA/UBern, BIRA, LATMOS, LMM, IRAP, MPS, SwRI, TUB, Umich  The seven papers published on 23 January 2015 in Science also show that the comet is rich in organic material and that the geological structures observed on the surface mainly result from erosion processes. In addition, the RPC-ICA instrument traced the evolution of the comet's magnetosphere, while the ROSINA spectrometer searched for evidence of the birth of the Solar System.

The composition of the comet's surface is very homogeneous, with a small difference in the neck region, which may contain water ice.


The nucleus of 67P/Churyumov-Gerasimenko

The images of comet 67P taken by the OSIRIS camera show an unusual overall shape made up of two lobes separated by a 'neck' of unknown origin. Its surface, whose overall composition is homogeneous, displays a wide variety of geological structures caused by erosion, collapse and redeposition processes. The comet's activity, which is surprising at such great distance from the Sun, is currently concentrated in the 'neck' region.

The entire series of images was used to make a three-dimensional model of the comet as well as map the detailed topography of Philae's original landing site. Combined with the measurement of its mass, this model has provided the first-ever direct determination of the density of a cometary nucleus, which implies that it is extremely porous. The model also provides a cartographic context for the interpretation of the results of the other experiments.

The surface properties of 67P/Churyumov-Gerasimenko

The MIRO instrument enabled the researchers to draw up a map of the near subsurface of 67P. The map shows seasonal and diurnal variations in temperature that point to low thermal conductivity of the surface of 67P, due to its porous, low-density structure. The researchers also carried out measurements of the comet's water production rate, which varies as the nucleus rotates, since the water outgassing from the comet is localized in its 'neck'.

Temperature map of the near subsurface of the nucleus (in isocontours) measured by the MIRO instrument. The illumination of the surface of the nucleus is shown in the background. The lowest temperatures (-250 °C, in blue) are on the non-sunlit side (on the left of the image).
Credit: © Gulkis et al.

A comet rich in organic material

VIRTIS provided the first detection of organic materials on a cometary nucleus. Its spectroscopic measurements indicate the presence of various materials containing carbon-hydrogen and/or oxygen-hydrogen bonds, while nitrogen-hydrogen bonds have not been detected at present. These species are associated with dark, opaque minerals such as iron sulfides (pyrrhotite and troilite). In addition, the measurements show that no water ice-rich patches exceeding twenty meters across are observed in sunlit regions, which indicates that the top few centimeters of the surface are strongly dehydrated.

The birth of a comet's magnetosphere

Using the RPC-ICA (Ion Composition Analyser) instrument, the researchers traced the evolution of water ions, from the first detection until the moment when the cometary atmosphere began to repel the solar wind (at around 3.3 AU ). They thus recorded the spatial structure of the early interaction between the solar wind and the thin cometary atmosphere, which gave rise to the formation of Churi's magnetosphere.

67P/Churyumov-Gerasimenko, a witness to the birth of the Solar System

Formed around 4.5 billion years ago and remaining frozen ever since, comets preserve traces of the original matter of the Solar System. The composition of their nucleus and coma thus gives us clues about the physical and chemical conditions in the early Solar System. The Rosetta spacecraft's ROSINA instrument measured the composition of 67P's coma (the coma is a sort of relatively dense atmosphere surrounding the nucleus, made up of a mixture of dust and gas molecules) by monitoring the comet's rotation. The results show that there are large fluctuations in the heterogeneous composition of the coma, as well as a complex coma-nucleus relationship where seasonal variations may be driven by temperature differences just below the comet surface..

Example of a circular pit observed on the nucleus of comet 67P.. Enhancing the contrast reveals the presence of activity. Image taken by the OSIRIS-NAC camera on 28 August 2014 from a distance of 60 km, with a spatial resolution of 1 m/pixel.

The dust of comet 67P/Churyumov-Gerasimenko

The GIADA dust detector has already collected a wealth of data (size, speed, direction, composition) about the dust emitted directly from the nucleus, which ranges in size from 0.1 to several millimeters. In addition, the OSIRIS images were also used to detect larger dust grains orbiting the nucleus, probably emitted during an earlier passage of the comet.

Contacts and sources:
CNRS (Délégation Paris Michel-Ange)

Friday, January 23, 2015

Chandra Celebrates The International Year of Light

The year of 2015 has been declared the International Year of Light (IYL) by the United Nations. Organizations, institutions, and individuals involved in the science and applications of light will be joining together for this yearlong celebration to help spread the word about the wonders of light.

To celebrate the International Year of Light, five Chandra images (M51, SNR E0519-69.0, MSH 11-62, Cygnus A, and RCW 86) have been released.

Image Credit: NASA/CXC/SAO

In many ways, astronomy uses the science of light. By building telescopes that can detect light in its many forms, from radio waves on one end of the “electromagnetic spectrum” to gamma rays on the other, scientists can get a better understanding of the processes at work in the Universe.

NASA’s Chandra X-ray Observatory explores the Universe in X-rays, a high-energy form of light. By studying X-ray data and comparing them with observations in other types of light, scientists can develop a better understanding of objects likes stars and galaxies that generate temperatures of millions of degrees and produce X-rays.

To recognize the start of IYL, the Chandra X-ray Center is releasing a set of images that combine data from telescopes tuned to different wavelengths of light. From a distant galaxy to the relatively nearby debris field of an exploded star, these images demonstrate the myriad ways that information about the Universe is communicated to us through light.

The images, beginning at the upper left and moving clockwise, are:

Messier 51 (M51):This galaxy, nicknamed the "Whirlpool," is a spiral galaxy, like our Milky Way, located about 30 million light years from Earth. This composite imagecombines data collected at X-ray wavelengths by Chandra (purple), ultraviolet by the Galaxy Evolution Explorer (GALEX, blue); visible light by Hubble (green), and infrared by Spitzer (red).

SNR E0519-69.0: When a massive star exploded in the Large Magellanic Cloud, a satellite galaxy to the Milky Way, it left behind an expanding shell of debris called SNR 0519-69.0. Here, multimillion degree gas is seen in X-rays from Chandra (blue). The outer edge of the explosion (red) and stars in the field of view are seen in visible light from Hubble.

MSH 11-62: When X-rays, shown in blue, from Chandra and XMM-Newton are joined in this image with radio data from the Australia Telescope Compact Array (pink) and visible light data from the Digitized Sky Survey (DSS, yellow), a new view of the region emerges. This object, known as MSH 11-62, contains an inner nebula of charged particles that could be an outflow from the dense spinning core left behind when a massive star exploded.

Cygnus A: This galaxy, at a distance of some 700 million light years, contains a giant bubble filled with hot, X-ray emitting gas detected by Chandra (blue). Radio data from the NSF's Very Large Array (red) reveal "hot spots" about 300,000 light years out from the center of the galaxy where powerful jets emanating from the galaxy's supermassive black hole end. Visible light data (yellow) from both Hubble and the DSS complete this view.

RCW 86:This supernova remnant is the remains of an exploded star that may have been witnessed by Chinese astronomers almost 2,000 years ago. Modern telescopes have the advantage of observing this object in light that is completely invisible to the unaided human eye. This image combines X-rays from Chandra (pink and blue) along with visible emission from hydrogen atoms in the rim of the remnant, observed with the 0.9-m Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory (yellow).

In addition to these newly released images, the Chandra X-ray Center has created a new online repository of images called "Light: Beyond the Bulb" for IYL. This project places astronomical objects in context with light in other fields of science and research.

NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cam

Contacts and sources:
Janet Anderson
Marshall Space Flight Center, Huntsville, Ala.

For more information on “Light: Beyond the Bulb,” visit the website at http://lightexhibit.org

For more information on the International Year of Light, go to http://www.light2015.org/Home.html

For more information and related materials, visit:

For more Chandra images, multimedia and related materials, visit:

Stardust On Ocean Floor Shows Gold And Uranium Alchemy In Stars Is Much Less Frequent Than Expected

Half the heavy elements in nature are created during stellar explosions such as supernovae or star collisions. Analyzing deep-sea samples of stardust that fell to Earth over millions of years, researchers made a surprising discovery about how frequently far-away stars produce heavy elements like gold and uranium. "Our analysis shows about 100 times less plutonium than we expected," says co-author Prof. Michael Paul at the Hebrew University's Racah Institute of Physics.

Bright spot on lower-left is Hubble Space Telescope-Image of Supernova 1994D (SN1994D) in galaxy NGC 4526. 
Photo by NASA/ESA 

Researchers combing the ocean depths have made a surprising discovery about the frequency with which stars beyond our solar system produce special heavy elements such as gold and uranium.

Stellar explosions such as supernovae or star collisions emit extremely bright light and vast amounts of energy and heavy matter. Half of the heavy elements in nature, including gold and uranium, are created during such events, yet their frequency and their very sites in the Galaxy remain a mystery.

By analyzing samples from the deep-sea floor that accumulated over millions of years, an international team of researchers concluded that the frequency of such events is much lower than expected.

The researchers analyzed core samples collected from the Pacific Ocean floor at about 4500 m water depth. They measured Pu-244, a rare isotope of plutonium that accumulated in the deep sea from the deposition of interstellar particles.

According to study co-author Prof. Michael Paul at the Hebrew University of Jerusalem's Racah Institute of Physics, "Our analysis of galactic debris that fell to Earth and settled in our oceans shows about 100 times less plutonium than we originally expected."

According to Prof. Paul, "The stellar dust that collects in our oceans provides new information about the far reaches of space as well as our own planet. Our research challenges current theories about supernovae and compounds the mystery surrounding how our solar system received its share of heavy elements. However it could be consistent with a particular astrophysical scenario, namely collisions or mergers of two neutron stars in the Milky Way Galaxy."

The findings are published in the January 2015 edition of the prestigious journal Nature Communications, as "Abundance of live 244Pu in deep-sea reservoirs on Earth points to rarity of actinide nucleosynthesis."

Partial funding for the research was provided by the Israel Science Foundation.

Contacts and sources:
Hebrew University of Jerusalem

Citation:Abundance of live 244Pu in deep-sea reservoirs on Earth points to rarity of actinide nucleosynthesis
NATURE COMMUNICATIONS | 6:5956 | DOI: 10.1038/ncomms6956
A Wallner, T. Faestermann, et al