Science News

3-D Printer Can Build Synthetic Tissues

2013-04-06T23:13:00.002-07:00

A custom-built programmable 3D printer can create materials with several of the properties of living tissues, Oxford University scientists have demonstrated.

The new type of material consists of thousands of connected water droplets, encapsulated within lipid films, which can perform some of the functions of the cells inside our bodies.

These printed 'droplet networks' could be the building blocks of a new kind of technology for delivering drugs to places where they are needed and potentially one day replacing or interfacing with damaged human tissues. Because droplet networks are entirely synthetic, have no genome and do not replicate, they avoid some of the problems associated with other approaches to creating artificial tissues -- such as those that use stem cells.

The team report their findings in this week's Science.

'We aren't trying to make materials that faithfully resemble tissues but rather structures that can carry out the functions of tissues,' said Professor Hagan Bayley of Oxford University's Department of Chemistry, who led the research. 'We've shown that it is possible to create networks of tens of thousands connected droplets. The droplets can be printed with protein pores to form pathways through the network that mimic nerves and are able to transmit electrical signals from one side of a network to the other.'

Each droplet is an aqueous compartment about 50 microns in diameter. Although this is around five times larger than living cells the researchers believe there is no reason why they could not be made smaller. The networks remain stable for weeks.

'Conventional 3D printers aren't up to the job of creating these droplet networks, so we custom built one in our Oxford lab to do it,' said Professor Bayley. 'At the moment we've created networks of up to 35,000 droplets but the size of network we can make is really only limited by time and money. For our experiments we used two different types of droplet, but there's no reason why you couldn't use 50 or more different kinds.'

The unique 3D printer was built by Gabriel Villar, a DPhil student in Professor Bayley's group and the lead author of the paper.

The droplet networks can be designed to fold themselves into different shapes after printing -- so, for example, a flat shape that resembles the petals of a flower is 'programmed' to fold itself into a hollow ball, which cannot be obtained by direct printing. The folding, which resembles muscle movement, is powered by osmolarity differences that generate water transfer between droplets.

Gabriel Villar of Oxford University's Department of Chemistry said: 'We have created a scalable way of producing a new type of soft material. The printed structures could in principle employ much of the biological machinery that enables the sophisticated behaviour of living cells and tissues.'

source: The above story is reprinted from materials provided byUniversity of Oxford.and science daily

Bird Call Database Nests Online

2010-12-08T07:39:00.001-08:00

A growing online library of bird sounds, photos and information offers a new resource for backyard birders and seasoned ornithologists alike.

The Avian Vocalizations Center at Michigan State University, or AVoCet,offers free downloads of bird sounds from around the world. It also features sonograms that visually chart the sounds, photos of birds recorded, Google Earth maps of recording locations and links to other online sound collections.

More than 10,200 recordings from over 3,190 species in 45 countries are now available on AVoCet, "and that's growing quickly," said Pamela Rasmussen, an assistant professor of zoology and assistant curator at the MSU Museum. "Soon recordings and their data from many more species and areas will be available for download from AVoCet."

There are, after all, 10,000 bird species, all of which make sounds of some type. Many birds, such as cardinals, even sing in regional dialects. Some birds have huge vocabularies -- a single male Brown Thrasher is known to give 2,000 different notes.

Author of an exhaustive reference work on the birds of South Asia, Rasmussen has personally recorded on all the continents for this project. Her work in the Philippines alone netted 597 recordings of 120 species, many of which are threatened. Some of those sound types are not publicly available anywhere other than AVoCet.

AVoCet also contains recordings made around the world so far by 65 others, including local ornithologists, professional guides and MSU students from Rasmussen's study abroad and ornithology courses. Zoology department programmer/analyst Patrick Bills built the database and Web site and undergraduate students also contributed.

Digital technology has revolutionized birding, Rasmussen explains, allowing enthusiasts and professionals to more easily record, share and play bird calls. Online access to the AVoCet library allows easy access to sounds, photos and other supporting information via computer and Internet-connected mobile devices.

The ability to identify birds vocally is crucial for monitoring bird movements and populations, including such popular events as the annual Christmas bird counts organized across the country. A comprehensive collection of bird sounds can yield better understanding of habitats, ranges and habits, while allowing more efficient and thorough biodiversity studies, Rasmussen said. "It's very difficult to see birds in a tropical rainforest, but not difficult to hear and recognize them."

Oriented to the scientific community, AVoCet maintains rigorous scholarly standards. Whenever possible, recordings are accompanied by photos and sighting observations that enable independent evaluation, Rasmussen said. Scientists can then accurately map avian biodiversity and perhaps identify new species.

"We know that certain species will go extinct in the near future and, sadly, there's not a lot that can realistically be done about it," Rasmussen said. "However, ornithologists and birders do now have the opportunity to document virtually all the species of birds out there in one way or another, and one major goal of AVoCet is to contribute to this effort."

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Michigan State University.

Tiny Laser Light Show Illuminates Quantum Computing

2010-12-08T07:38:00.000-08:00

A new laser-beam steering system that aims and focuses bursts of light onto single atoms for use in quantum computers has been demonstrated by collaborating researchers from Duke University and the University of Wisconsin-Madison.

Described in the journal Applied Physics Letters, published by the American Institute of Physics, the new system is somewhat like the laser-light-show projectors used at rock concerts and planetariums. But it's much smaller, faster, atom-scale accurate and aimed at the future of computing, not entertainment.

In theory, quantum computers will be able to solve very complex and important problems if their basic elements,

called qubits, remain in a special "quantum entangled" state for a long enough time for the calculations to be carried out before information is lost to natural fluctuations. One of several promising approaches to quantum computing uses arrays of individual atoms suspended by electromagnetic forces. Pulses of laser light manipulate the internal states of the atoms that represent the qubits, to carry out the calculation. However the lasers must also be focused and aimed so accurately that light meant for one atom doesn't affect its neighbors.

The new system did just that. Tiny micromirrors, each only twice the diameter of a human hair, pointed to each target atom in as little as 5 microseconds, which is about 1,000 times faster than sophisticated beam-steering mirrors developed for optical communications switching, not to mention the still slower units used in light shows. The researchers saw that the laser pulses also correctly manipulated the quantum properties of each target atom -- in this case a line of five rubidium-87 atoms -- without disturbing any neighboring atoms, which were separated by just 8.7 microns, about one-tenth the diameter of a human hair.

"Our experiments demonstrated the crucial requirement that our micromirror system maintain the laser-beam quality necessary to manipulate the internal states of the individual atoms," said Jungsang Kim, leader of the Duke researchers who designed the micromirror system. The atomic physics experiments were performed in Mark Saffman's group at University of Wisconsin-Madison.

The groups plan to continue their collaboration, with future experiments targeting two-qubit gates, which are expected to be the basic building block of quantum logic, and atoms confined in larger two-dimensional arrays.

This work was funded by the Army Research Office, the Intelligence Advanced Research Projects Activity (IARPA), and the National Science Foundation.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by American Institute of Physics, via EurekAlert!, a service of AAAS.

Double Vision: New Instrument Casts Its Eyes to the Sky

2010-12-08T07:37:00.000-08:00

The Large Binocular Telescope Interferometer has taken its first images of the star Beta Peg in the constellation Pictor -- an encouraging start for an instrument designed to probe the cosmic neighborhoods where Earth-like planets could exist.

Eight years in development, the NASA-funded instrument combines beams of light from twin 8.4-meter (28-foot) mirrors mounted atop the Large Binocular Telescope on Mount Graham, Ariz. "By combining the light of the telescopes, we're able to realize its full potential," said Project Manager Tom McMahon of the University of Arizona, Tucson. "Together, the two mirrors form the largest single-mount telescope in the world."

"The quality of the first-light images is wonderful," said the principal investigator for the project, Phil Hinz of the University of Arizona. "The telescope was stable and the instrument was working properly."

With this high-resolution imaging capability, astronomers hope to probe nearby solar systems -- specifically, the areas in these systems where Earth-like planets with liquid water could exist. Though the Large Binocular Telescope Interferometer won't be able to detect Earth-size planets, it will be able to see dust disks that are indicative of planet formation, in addition to detecting large, Jupiter-size planets farther out from the star. These findings will help future, space-based exoplanet missions know where to search for Earth-like planets in our own galactic neighborhood.

With its ability to probe this "habitable zone" of other solar systems, the Large Binocular Telescope Interferometer will also complement the capabilities of other NASA missions -- the Keck Interferometer, which can find dust very close to stars; and the Spitzer Space Telescope, which is adept at observing planet-forming dust that is much more distant.

"This instrument will help complete our picture of what planetary systems look like and be a pathfinder for finding Earth-like planets that are close by," Hinz said.

With a major upgrade of the Large Binocular Telescope's adaptive optics system scheduled for next year, the interferometer will undergo testing and commissioning for the majority of 2011, and during that time, scientific observations will begin.

"This is the highest-resolution instrument of its kind in the world," McMahon said. "We won't just be able to image exoplanets, but extragalactic objects, nebulae and galaxies. It's taken time to make sure it works as envisioned, but now it's time to do science."

The Large Binocular Telescope Interferometer is funded by NASA and managed by Ben Parvin at NASA's Jet Propulsion Laboratory, Pasadena, Calif., as part of NASA's Exoplanet Exploration Program. The instrument and product development are provided by the University of Arizona, Tucson.

More information about the Large Binocular Telescope Interferometer can be found at: http://lbti.as.arizona.edu/LBTI-Main/Project.html

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA/Jet Propulsion Laboratory. The original article was written by Josh Rodgriguez

A Swarm of Ancient Stars

2010-12-08T07:35:00.001-08:00

The globular cluster Messier 107, also known as NGC 6171, is a compact and ancient family of stars that lies about 21 000 light-years away. Messier 107 is a bustling metropolis: thousands of stars in globular clusters like this one are concentrated into a space that is only about twenty times the distance between our Sun and its nearest stellar neighbour, Alpha Centauri, across. A significant number of these stars have already evolved into red giants, one of the last stages of a star's life, and have a yellowish colour in this image.

Globular clusters are among the oldest objects in the Universe. And since the stars within a globular cluster formed from the same cloud of interstellar matter at roughly the same time -- typically over 10 billion years ago -- they are all low-mass stars, as lightweights burn their hydrogen fuel supply much more slowly than stellar

behemoths. Globular clusters formed during the earliest stages in the formation of their host galaxies and therefore studying these objects can give significant insights into how galaxies, and their component stars, evolve.

Messier 107 has undergone intensive observations, being one of the 160 stellar fields that was selected for the Pre-FLAMES Survey -- a preliminary survey conducted between 1999 and 2002 using the 2.2-metre telescope at ESO's La Silla Observatory in Chile, to find suitable stars for follow-up observations with the VLT's spectroscopic instrument FLAMES [1]. Using FLAMES, it is possible to observe up to 130 targets at the same time, making it particularly well suited to the spectroscopic study of densely populated stellar fields, such as globular clusters.

M107 is not visible to the naked eye, but, with an apparent magnitude of about eight, it can easily be observed from a dark site with binoculars or a small telescope. The globular cluster is about 13 arcminutes across, which corresponds to about 80 light-years at its distance, and it is found in the constellation of Ophiuchus, north of the pincers of Scorpius. Roughly half of the Milky Way's known globular clusters are actually found in the constellations of Sagittarius, Scorpius and Ophiuchus, in the general direction of the centre of the Milky Way. This is because they are all in elongated orbits around the central region and are on average most likely to be seen in this direction.

Messier 107 was discovered by Pierre Méchain in April 1782 and it was added to the list of seven Additional Messier Objects that were originally not included in the final version of Messier's catalogue, which was published the previous year. On 12 May 1793, it was independently rediscovered by William Herschel, who was able to resolve this globular cluster into stars for the first time. But it was not until 1947 that this globular cluster finally took its place in Messier's catalogue as M107, making it the most recent star cluster to be added to this famous list.

This image is composed from exposures taken through the blue, green and near-infrared filters by the Wide Field Camera (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by ESO.

New Observations of Exploding Stars Reveal Pauses, Flickers and Flares Not Reliably Seen Before

2010-12-08T07:34:00.000-08:00

Astronomers have traced the waxing and waning light of exploding stars more closely than ever before and seen patterns that aren't yet accounted for in our current understanding of how these eruptions occur.

Using data from a sensitive instrument aboard a satellite that images the entire sky every 102 minutes, they studied four of these stars, or novae, that exploded so violently their light would have been visible without a telescope and measured their brightness over the course of the outburst.

Three of the novae stalled before reaching a peak, and all flickered or flared as the explosions ran their course,

they report in The Astrophysical Journal.

The instrument they used -- the Solar Mass Ejection Imager -- was developed by a team led by astrophysicist Bernard Jackson at the Center for Astrophysics and Space Sciences at the University of California, San Diego, to study the sun. Rebekah Hounsell, a graduate student at Liverpool John Moores University in Britain made the measurements while visiting UC San Diego.

Because starlight is a distraction for Jackson's team, noise they must subtract from their data so that they can focus on the sun's outer corona and the heliosphere, they make detailed maps of stellar light, including its brightness.

In those maps Hounsell identified the four novae by finding points of light that rapidly brightened and dimmed over the course of days.

Wavering Light

Other astronomers had observed a pause in the brightening of novae, or "pre-maximum halt" before, but some thought it an anomaly. The precise time-scale and repeated observations of the current study confirms it, they authors say.

"The reality of this halt as found in all three of the fast-declining novae observed is a challenge to detailed models of the nova outburst," said one of the authors, astrophysicist Mike Bode, of Liverpool John Moores University.

Two independent teams of theorists have already begun to refine their models of how novae explode in response.

Astronomers typically characterize novae's changing light with curves smoothly fit to more sporadic observations, but the rapid cadence of the solar imager captured glimmers that hadn't been observed before. All flickered as their light dimmed and one nova, the slowest of the four to dim, flared brightly twice after reaching its peak luminosity.

These novae are white dwarf stars that steal matter, in the form of hydrogen, from a companion star, often an aging, expanding red giant. As hydrogen accumulates the white dwarf's gravity pulls it in and condenses it until it ignites, setting off a runaway nuclear fusion reaction.

The team speculates that the post-peak flares may correspond to changes in the dynamics of that reaction that still need to be explained.

Catching Missing Stars

"Before Hounsell looked through these data, most novae were observed only after their peak luminance. The instrument's very even cadences and uniformly exposed images allow us to trace the entire evolution of these explosions as they brighten and dim," UC San Diego's Jackson said.

Data from the imager, which has been in operation aboard the Coriolis satellite since January 2003, allows astronomers to measure novae that they initially missed.

"Even today novae are mainly discovered by amateur astronomers around the world who then alert their professional counterparts to conduct observations," Hounsell said.

As many as five novae bright enough to be detected by SMEI explode in our galaxy each year, Allen Shafter, astronomy professor at San Diego State University and one of the co-authors of the report have previously estimated, but more than half have gone undetected.

"The instrument assures that the brightest and most rapidly evolving novae -- ones that brighten and then fade within a few days -- are not overlooked," Shafter said. "The high time resolution of these observations has opened up a new window into the study of novae in our galaxy."

Bernard Jackson's research at UC San Diego is supported by the National Science Foundation and NASA. Allen Shafter's work at San Diego State University is supported by the National Science Foundation.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of California - San Diego. The original article was written by Susan Brown.

How Flowering Time of Plants Can Be Controlled

2010-12-08T07:32:00.000-08:00

Researchers at Umeå Plant Science Center in Sweden discovered, in collaboration with the Syngenta company, a previously unknown gene in sugar beets that blocks flowering. Only with the cold of winter is the gene shut off, allowing the sugar beet to blossom in its second year. The discovery of this new gene function makes it possible to control when sugar beets bloom.

The new findings were recently published in the journal Science.

Scientists at Umeå Plant Science Center and the international company Syngenta, in a joint study of genetic regulation in the sugar beet, have discovered an entirely new principle for how flowering can be controlled. The

study, which was co-directed by Professorn Ove Nilsson, of the Swedish University of Agricultural Sciences

(SLU), and Syngenta scientist Dr. Thomas Kraft, showed that there is a gene in the sugar beet that was previously unknown.

"When we studied a gene in the sugar beet that usually stimulates blooming in other plants, we made a very surprising discovery: in the sugar beet evolution has developed a 'sister gene' that has taken on the exact opposite function, namely, to inhibit blossoming. For biennial sugar beets this means that they can't flower in their first year. Once the plants have been exposed to the cold of winter at the end of the first year, the 'gene blockade is lifted,' and the sugar beets can bloom in their second year of life," says Ove Nilsson about the function of the newly discovered flowering gene.

The researchers speculate that the development of the inhibiting sister gene was an important factor in enabling biennial sugar beets to evolve from an annual to a biennial plant. Furthermore, plant researchers in Umeå and Landskrona have shown that it is possible to manipulate the "flowering gene" in such a way as to leave the gene constantly "turned on," that is, to block blooming, and thereby prevent it from being turned off after winter.

"In that way it's possible to fully control the flowering time of the sugar beet. This enables us to develop a so-called 'winter beet,' that is, a sugar beet that can be planted in the autumn and then will continue to grow throughout the following growth season without blossoming," says Thomas Kraft at Syngenta Seeds.

"A winter beet has be a high priority for sugar beet growers, since it is estimated to be able to increase the yield by about 25 percent and at the same time allow a more extended harvesting period. Traditional breeding has failed to produce such a plant. Syngenta Seeds is now going to move on to more in-depth tests of this potential new winter beet."

The research work in this project has been primarily conducted by an industrial doctoral candidate, Pierre Pin, with funding from the Swedish Research Council and Syngenta Seeds AB.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided byExpertanswer, via AlphaGalileo.

Social Relationships in Animals Have a Genetic Basis, New Research Reveals

2010-12-08T07:28:00.000-08:00

The ability to tolerate aggression is partly genetic, UCLA life scientists report in the first study to demonstrate a genetic component to a social network trait in a non-human population.

The ability to tolerate aggression is passed on across generations; there is genetic variation in the ability to tolerate aggression," said the study co-author Daniel T. Blumstein, professor and chair of ecology and evolutionary biology at UCLA.

Blumstein, a leader in the field of applying social network statistics to animals, and his colleagues studied four groups of yellow-bellied marmots, which are related to squirrels, over six years in the Rocky Mountains of Colorado. Each group included 15 to 30 marmots.

To study the social behavior of the animals, the biologists applied the same type of social network statistics that Google and Facebook use to study human behavior.

"We are gaining a novel insight into the importance of tolerating aggressive interactions," Blumstein said. "Those relationships are important for social stability and reproductive success. I believe these ideas are generalizable well beyond marmots."

The research, funded by the National Science Foundation and the National Geographic Society, is currently published in the online early edition of the journal Proceedings of the National Academy of Sciences and will appear Dec. 14 in the journal's print edition.

The paper's lead author, Amanda Lea, a former UCLA honors student who is now a research assistant in ecology

and evolutionary biology, spent two summers observing the marmots for four hours a day and analyzing their behavior -- from far enough away not to affect it. She can tell the marmots apart.

"We found that having many friendly interactions gave marmots fitness benefits -- these marmots reproduced more. But surprisingly, we found that marmots embedded in a network of unfriendly interactions also showed higher fitness levels," Lea said. "Over a lifetime, a marmot that is very social will have more offspring than a less social one. But surprisingly, so will a marmot that is getting picked on frequently."

"The family unit is important, even if their interactions are not always nice," Blumstein said of the finding.

Like people, some marmots are quite friendly, some keep to themselves and some are more aggressive, Lea said. They live in family groups, groom one another, sit next to one another, play together and, much less frequently, fight. They live up to 15 years, Blumstein said.

Female marmots typically have three to nine offspring a year and can have as many as 60 over a lifetime. Some males can have as many as 150 or more, although most have many fewer, Blumstein said.

Blumstein, Lea and colleagues applied social networking statistics, computational analysis and quantitative genetics to marmots' social behavior. They studied, for example, whether interactions were friendly or aggressive, and they applied state-of-the-science statistical techniques to estimate the heritability of traits and whether particular traits are correlated with reproductive success.

With his colleagues, Blumstein, who has studied marmots for more than 20 years to learn about their biology and evolution, quantified the genetic component to the marmots' social behaviors. Genetic factors account for some 10 percent of the differences among marmots, while about 20 percent of the variation is due to the social environment, they calculated.

"There is a genetic component to certain social behaviors, and we have quantified that," Blumstein said.

Because social behavior has a genetic component, he said, a social trait has the ability to carry on across generations and evolve.

"Social network statistics can be a useful way to study a variety of animals and understand social evolution," Blumstein said. "This study says that traits we define using social network analyses can evolve, and that has not been demonstrated like this before."

The life scientists made predictions and found some surprising results.

"We predicted that direct and immediate relationships, over which an individual has control, might have a higher heritability (a genetic basis) than indirect relationships," Blumstein said.

"We found that direct measures were heritable and indirect measures were not; we expected this," he said. "However, within these direct relationships, you might expect that things I do to you, things I have control over, would have significant heritability, but what we found is the opposite: the ability to tolerate aggression is heritable, and we found that fascinating. Tolerating aggression is, surprisingly, very important in marmots and perhaps in other species."

"Many people have perhaps not recognized the benefits of aggressive interactions, even if you are on the receiving end," Lea said.

Blumstein said the findings have important implications for why animals are social.

These marmots in Colorado have been studied since 1962 -- one of the longest-running animal studies. Blumstein has studied marmots worldwide, and these for more than a decade.

"Once we had a good genealogy, a good understanding of the genetic relationships among them, we were able to ask questions about the heritability of various behaviors -- the ability of a behavior to be passed on from generation to generation," he said.

Why has Blumstein devoted so much of his research to studying these animals?

"Most species do not have an address, but marmots do, and because they have an address, you can set up camp and study them," he said. "You can go to their burrows every day and watch them. We can learn a lot about evolution, the adaptive value of sociality and the adaptive value of complex communication by studying marmots and ground squirrels."

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of California - Los Angeles. The original article was written by Stuart Wolpert

Using Chaos to Model Geophysical Phenomena

2010-12-08T07:26:00.001-08:00

Geophysical phenomena such as the dynamics of the atmosphere and ocean circulation are typically modeled mathematically by tracking the motion of air or water particles. These mathematical models define velocity fields that, given (i) a position in three-dimensional space and (ii) a time instant, provide a speed and direction for a particle at that position and time instant.

"Geophysical phenomena are still not fully understood, especially in turbulent regimes," explains Gary Froyland at the School of Mathematics and Statistics and the Australian Research Council Centre of Excellence for Mathematics and Statistics of Complex Systems (MASCOS) at the University of New South Wales in Australia.

"Nevertheless, it is very important that scientists can quantify the 'transport' properties of these geophysical

systems: Put very simply, how does a packet of air or water get from A to B, and how large are these packets? An example of one of these packets is the Antarctic polar vortex, a rotating mass of air in the stratosphere above Antarctica that traps chemicals such as ozone and chlorofluorocarbons (CFCs), exacerbating the effect of the CFCs on the ozone hole," Froyland says.

In the American Institute of Physics' journal Chaos, Froyland and his research team, including colleague Adam Monahan from the School of Earth and Ocean Sciences at the University of Victoria in Canada, describe how they developed the first direct approach for identifying these packets, called "coherent sets" due to their nondispersive properties.

This technique is based on so-called "transfer operators," which represent a complete description of the ensemble evolution of the fluid. The transfer operator approach is very simple to implement, they say, requiring only singular vector computations of a matrix of transitions induced by the dynamics.

When tested using European Centre for Medium Range Weather Forecasting (ECMWF) data, they found that their new methodology was significantly better than existing technologies for identifying the location and transport properties of the vortex.

The transport operator methodology has myriad applications in atmospheric science and physical oceanography to discover the main transport pathways in the atmosphere and oceans, and to quantify the transport. "As atmosphere-ocean models continue to increase in resolution with improved computing power, the analysis and understanding of these models with techniques such as transfer operators must be undertaken beyond pure simulation," says Froyland.

Their next application will be the Agulhas rings off the South African coast, because the rings are responsible for a significant amount of transport of warm water and salt between the Indian and Atlantic Oceans.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by American Institute of Physics, via EurekAlert!, a service of AAAS.

Plants 'Remember' Winter to Bloom in Spring With Help of Special Molecule

2010-12-08T07:25:00.001-08:00

The role a key molecule plays in a plant's ability to remember winter, and therefore bloom in the spring, has been identified by University of Texas at Austin scientists

Many flowering plants bloom in bursts of color in spring after long periods of cold in the winter. The timing of blooming is critical to ensure pollination, and is important for crop production and for droves of people peeping at wildflowers.

One way for the plants to recognize the spring -- and not just a warm spell during winter -- is that they "remember" they've gone through a long enough period of cold.

"Plants can't literally remember, of course, because they don't have brains," says Sibum Sung, assistant

professor in the Section of Molecular Cell and Developmental Biology. "But they do have a cellular memory of winter, and our research provides details on how this process works."

The process is known as vernalization, whereby a plant becomes competent to flower after a period of cold. And though it is common for many plants adapted to temperate climates, including important crops like winter wheat, it has not been until the past decade or so that scientists have begun to understand the process's genetic and molecular underpinnings.

Sung and postdoctoral fellow Jae Bok Heo have now discovered that a long, non-coding RNA molecule, named COLDAIR, is required for plants to set up a memory of winter.

They published their work on the Arabidopsis plant in ScienceExpress on Dec. 2.

This is how it works: In fall, a gene called FLC actively represses floral production. A random bloom in fall could be a waste of precious energy.

But after a plant has been exposed to 20 days of near-freezing temperatures, the scientists found that COLDAIR becomes active. It silences the FLC gene, a process that is completed after about 30 to 40 days of cold. With the FLC silenced as temperatures warm in the spring, other genes are activated that initiate blooming.

COLDAIR helps create a cellular memory for a plant, letting it know it has been through 30 or more days of cold.

But, how does the cold actually turn on COLDAIR?

"That is one of the next questions we have," says Sung. "How do plants literally sense the cold?"

Answering these kinds of basic questions could lead to crop improvements and will be important to grasp as climate changes alter the length of the winter season, with possible repercussions to vernalization in plants around the world.

This research was supported with funds from the National Science Foundation and The University of Texas at Austin.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Texas at Austin, via EurekAlert!, a service of AAAS.

Doctor Who's Trusty Invention Is Anything but Sci-Fi: Sonic Screwdriver to Solve Future DIY Woes

2010-12-08T07:24:00.000-08:00

Television's favourite Time Lord could not exist without his trusty sonic screwdriver, as it's proved priceless in defeating Daleks and keeping the Tardis in check. Now Doctor Who's famous cure-all gadget could become a reality for DIY-ers across the world, say engineers.

Ultrasonic engineers at Bristol University and The Big Bang: UK Young Scientists and Engineers Fair (http://www.thebigbangfair.co.uk/) are uncovering how a real life version of the fictional screwdriver -- which uses sonic technology to open locks and undo screws -- could be created.

Professor of Ultrasonics, Bruce Drinkwater, who is working with The Big Bang to inspire young scientists of the future, says the answer lies in ultrasonic sound waves. By operating the waves at frequencies way beyond the

realms of human hearing, they can be used to apply forces to objects.

The technology is already being trialled in modern manufacturing to fix parts together and ultrasonic force fields are being developed within the medical field to separate diseased cells from healthy cells. Professor Drinkwater and The Big Bang team are now exploring whether super powerful versions of these sound beams could bring Doctor Who's iconic device to life.

He says: "Doctor Who is renowned for bending the rules of science. But technology has radically moved on since the Doc first stepped out of his Tardis in the sixties. Whilst a fully functioning time machine may still be light years away, engineers are already experimenting with ultrasonic waves to move and manipulate small objects."

Engineers are looking into how ultrasonic waves can be spun at high speed to create a twisting force similar to that of a miniature tornado, which could undo screws remotely. They have also experimented with rotating ultrasonic force fields which would act like the head of a real screwdriver.

Doctor Who and DIY fans may still have to wait before they can add the sonic screwdriver to their Christmas wish lists. However, Professor Drinkwater hopes his work to make the impossible possible will inspire engineers, technologists and inventors of the future.

"Doctor Who's adventures have captured the imaginations of millions, young and old. And, however far fetched the Time Lord's encounters may seem, there are engineers and scientists out there who are using their skills to bring the magic to life.

"The sonic screwdriver may still be sometime in the making but ultrasonic technology is already making its mark in the medical and manufacturing arenas with some exciting results."

Professor Drinkwater has teamed up with The Big Bang, one of the UK's biggest celebrations of science and engineering, to inspire young people from all walks of life.

Taking place at ICC London ExCeL from 10 -- 12 March 2011, The Big Bang offers young people the chance to take part in a host of free interactive shows and workshops including Sky One's Brainiac Live! and BBC One's Bang Goes the Theory. It is also the ideal place to find out about the exciting career options available in science and engineering. The Big Bang hosts the finals of the prestigious National Science & Engineering Competition and also kicks off National Science & Engineering Week 2011.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Bristol.

Life Found Thriving in Porous Rock Deep Beneath the Seafloor

2010-12-08T07:22:00.000-08:00

Researchers have found compelling evidence for an extensive biological community living in porous rock deep beneath the seafloor. The microbes in this hidden world appear to be an important source of dissolved organic matter in deep ocean water, a finding that could dramatically change ideas about the ocean carbon cycle.

Matthew McCarthy, associate professor of ocean sciences at the University of California, Santa Cruz, led a team of researchers from several institutions who analyzed the dissolved organic matter in fluids from natural vents on the seafloor and from a borehole that penetrated the basement rock deep beneath the seafloor sediments. Their results, to be published in the January issue ofNature Geoscience and currently available online, indicate that the dissolved material in those fluids was synthesized by microbes living in the porous basalt rock of the upper

oceanic crust. These microbes are "chemoautotrophic," meaning they derive energy from chemical reactions and are completely independent of the sunlight-driven life on the surface of our planet.

Chemoautotrophic microbes (bacteria and archaea) have been found in deep-ocean sediments and at hydrothermal vents, where hot water flows out through newly formed volcanic rock at mid-ocean ridges. The idea that a much larger biological community might exist in habitats within the cooler upper-crustal rock that lies under large areas of the seafloor has been an exciting, but controversial, hypothesis, McCarthy said.

"What is really important about this is the huge size and extent of such systems," he said. "This study provides the strongest evidence yet that a really large biosphere exists in the warm fluids in the porous upper-oceanic crust. It's large not just in area, but in productivity. In the same way that forests and grasslands fix carbon and produce organic matter on land, our data suggest these microbes produce enough organic matter to export carbon to other systems. That's a real expansion of our ideas about the oceanic carbon cycle."

The existence of an extensive "alternate biosphere" beneath the ocean floor may also influence the thinking of astrobiologists about where life might exist elsewhere in our solar system, McCarthy said. Saturn's moon Europa, for example, is thought to have liquid oceans beneath its icy crust, prompting speculation about the possibility of life evolving there.

McCarthy's team found evidence of the hidden microbial ecosystem beneath the seafloor by analyzing carbon isotopes in the organic molecules in their samples. Of the three naturally occurring isotopes of carbon, carbon-12 is the most abundant, and both carbon-12 and the slightly heavier carbon-13 are stable. Carbon-14 is an unstable isotope formed in the upper atmosphere through the action of cosmic rays, and its steady decay is the basis for carbon-dating of organic material.

The ratios of these different isotopes provide telltale clues to the origins of organic molecules and the carbon atoms in them. Carbon-13 analysis, for example, indicates what kind of organisms synthesized the molecules. "Carbon-13 is really useful for looking at the origins of organic matter, because there are distinctive signatures for different sources," McCarthy said. "Chemosynthetic bacteria have wildly different signatures than anything else, and our carbon-13 results match the classic chemosynthetic values."

The team's carbon-14 analysis showed where the carbon in the organic molecules came from. If it came from the carbon in crustal rocks, there would be no carbon-14 at all. Instead, the carbon-14 signature indicated that the carbon came from dissolved inorganic carbon in deep seawater. This inorganic carbon pool consists of carbonate ions formed when carbon dioxide from the atmosphere dissolves in ocean water.

Carbon-14 dating indicated that the carbon in the dissolved organic matter is 11,800 to 14,400 years old--in other words, that's how long ago the carbon now in those organic molecules was absorbed from the atmosphere into the ocean. That's about three times older than the carbon-14 age of the overall pool of dissolved organic matter in the deep ocean. This suggests that water circulates very slowly through the deep microbial habitat in the rocks of the upper crust.

"The observation that this deep biosphere is apparently pumping very old, carbon-14-depleted dissolved organic matter into the deep ocean may be very important to our understanding of biogeochemical cycles," McCarthy said. "The reservoir of dissolved organic matter in the deep ocean is one of the largest active pools of organic carbon in the global carbon cycle, about the same size as the pool of atmospheric carbon dioxide."

The age of the deep-ocean water is used to estimate how quickly it turns over and returns to the surface layers. "If this very old pool of carbon is being mixed in and biasing the measurements, the deep-ocean water may actually be turning over more quickly than we thought," McCarthy said.

To obtain their samples, the researchers used custom-built equipment and a remotely operated deep-sea submersible, the ROV Jason II, from Woods Hole Oceanographic Institution (WHOI). Stainless-steel probes driven into an exposed rock outcrop and a specialized set of deep-sea sampling platforms designed at the University of Washington (UW) enabled them to recover the unprecedented quantities of uncontaminated crustal fluids needed for the analyses. The samples were collected during two expeditions to the Juan de Fuca Ridge system off the coast of Washington and British Columbia.

The key carbon-14 measurements on the recovered organic molecules were done through collaborations with the Lawrence Livermore National Laboratory's accelerator facility and the Keck Carbon Cycle Accelerator facility at UC Irvine. In addition to McCarthy, the coauthors include Steven Beaupré of WHOI; UCSC graduate student Brett Walker; Ian Voparil of Shell International Exploration and Production; Thomas Guilderson of Lawrence Livermore National Laboratory; and Ellen Druffel of UC Irvine. H. Paul Johnson and Tor Bjorkland of the UW School of Oceanography were instrumental in the development and deployment of deep-sea samplers and probes.

This research was supported by the National Science Foundation, the University of California, and the Packard Foundation.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of California - Santa Cruz.

Drugs Can Pass Through Human Body Almost Intact: New Concerns for Antibiotic Resistance, Pollution Identified

2010-12-08T07:20:00.001-08:00

When an antibiotic is consumed, researchers have learned that up to 90 percent passes through a body without metabolizing. This means the drugs can leave the body almost intact through normal bodily functions.

In the case of agricultural areas, excreted antibiotics can then enter stream and river environments through a variety of ways, including discharges from animal feeding operations, fish hatcheries, and nonpoint sources such as the flow from fields where manure or biosolids have been applied. Water filtered through wastewater treatment

plants may also contain used antibiotics.

Consequently, these discharges become "potential sources of antibiotic resistance genes," says Amy Pruden, a National Science Foundation CAREER Award recipient, and an assistant professor of civil and environmental engineering at Virginia Tech.

"The presence of antibiotics, even at sub-inhibitory concentrations, can stimulate bacterial metabolism and thus contribute to the selection and maintenance of antibiotic resistance genes," Pruden explains. "Once they are present in rivers, antibiotic resistance genes are capable of being transferred among bacteria, including pathogens, through horizontal gene transfer."

The World Health Organization and the Center for Disease Control recognize antibiotic resistance "as a critical health challenge of our time," Pruden writes in a paper published in a 2010 issue of Environmental Science and Technology.

Pruden says reducing the spread of antibiotic resistance is a critical measure needed to prolong the effectiveness of currently available antibiotics. This is important since "new drug discovery can no longer keep pace with emerging antibiotic-resistant infections," Pruden says.

Pruden who has developed the concept of antibiotic resistance genes as environmental pollutants has an international reputation in applied microbial ecology, environmental remediation, and environmental reservoirs of antimicrobial resistance.

In her work outlined in the Environmental Science and Technology article, she and her co-authors, H. Storteboom, M. Arabi and J.G. Davis, all of Colorado State University, and B. Crimi of Delft University in The Netherlands, identified specific patterns of antibiotic resistance gene occurrence in a Colorado watershed. Identification of these patterns represents a major step in being able to discriminate between agricultural and wastewater treatment plant sources of these genes in river environments.

They assert that such unique patterns of antibiotic resistance gene occurrence represent promising molecular signatures that may then be used as tracers of specific manmade sources.

In their study they identified three wastewater treatment plant sites, six animal feeding operation locations, and three additional locations along a pristine region of the Poudre River, in an upstream section located in the Rocky Mountains. They compared the frequency of detection of 11 sulfonamide and tetracycline antibiotic resistance genes.

Their findings showed detection of one particular antibiotic resistance gene in 100 percent of the treatment plant and animal feeding operations, but only once in the clean section of the Poudre River.

As they are able to differentiate between human and animal sources of the antibiotic resistance genes, Pruden and her colleagues believe they can "shed light on areas where intervention can be most effective in helping to reduce the spread of these contaminants through environmental matrixes such as soils, groundwater, surface water and sediments.

"This study advances the recognition of antibiotic resistance genes as sources to impacted environments, taking an important step in the identification of the dominant processes of the spreading and transport of antibiotic resistance genes."

The Colorado Water Resources Research Institute and a USDA Agricultural Experiment Station provided funding for this study in addition to Pruden's NSF award.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Virginia Tech, via EurekAlert!, a service of AAAS.

Researchers Find Mathematical Patterns to Forecast Earthquakes

2010-12-07T08:33:00.000-08:00

Researchers from the Universidad Pablo de Olavide (UPO) and the Universidad de Sevilla (US) have found patterns of behaviour that occur before an earthquake on the Iberian peninsula. The team used clustering techniques to forecast medium-large seismic movements when certain circumstances coincide.

"Using mathematical techniques, we have found patterns when medium-large earthquakes happen, that is, earthquakes greater than 4.4 on the Richter scale," said Francisco Martínez Álvarez, co-author of the study and a

senior lecturer at the UPO.

The research, which will be published this month by the journal Expert Systems with Applications, is based on the data compiled by the Instituto Geográfico Nacional on 4,017 earthquakes between 3 and 7 on the Richter scale that occurred on the Iberian Peninsula and in the surrounding waters between 1978 and 2007.

The scientists applied clustering techniques to the data, which allowed them to find similarities between them and discover patterns that will help to forecast earthquakes.

The team concentrated on the two seismogenic regions with the most data (The Alboran Sea and the Western Azores-Gibraltar fault region) analysing three attributes: the magnitude of the seismic movement, the time elapsed since the last earthquake and the change in a parameter called the b-value from one earthquake and the other. The b-value reflects the tectonics of the region under analysis.

A high b-value means earthquakes are predominantly small in size and, therefore, the land has a low level of resistance. In contrast, a low value indicates that there are a relatively similar number of large and small seismic movements, which implies the land is more resistant.

Successful Forecast Probability Greater than 80%

"We have discovered the strong relationship between earthquakes and the parameter b-value, recording accuracy rates of more than 80%," Antonio Morales Esteban, another of the co-authors of the study and a senior lecturer at the US highlighted. "After the calculations had been performed, providing the circumstances and sequences we have determined to be forerunners occur, we obtain a significant success probability."

The technique summarises the forecasts in two factors: sensitivity (probability of an earthquake occurring after the patterns detected occur) and specificity (probability of an earthquake not occurring when no patterns have occurred).

The results reflect a sensitivity of 90% and specificity of 82.56% for the Alboran Sea region and 79.31% and 90.38% respectively for the seismogenic region of the Western Azores-Gibraltar Fault.

That is, there is a high probability of an earthquake in these regions immediately after the patterns discovered occur (high sensitivity) and, moreover, on most of such occasions, they only occur after the patterns discovered (high specificity).

At present the team is analysing the same data using their own algorithms based on "association rules," other mathematical techniques used to discover common events or those which fulfil specific conditions within a set of events.

"The results are promising, although I doubt we will ever be able to say that we are capable of forecasting an earthquake 100% accurately," Martínez Álvarez conceded.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by FECYT - Spanish Foundation for Science and Technology, viaEurekAlert!, a service of AAAS.

Virtual Biopsy May Allow Earlier Diagnosis of Brain Disorder in Athletes

2010-12-07T08:22:00.000-08:00

In a study of ex-pro athletes, researchers found that a specialized imaging technique called magnetic resonance spectroscopy (MRS) may help diagnose chronic traumatic encephalopathy (CTE), a disorder caused by repetitive head trauma that currently can only be definitively diagnosed at autopsy. Results of the study were presented at the annual meeting of the Radiological Society of North America (RSNA).

"The devastating effects of brain injuries suffered by pro football players who repeatedly suffered concussions and subconcussive brain trauma during their careers have put the spotlight on CTE," said Alexander P. Lin, Ph.D., a principal investigator at the Center for Clinical Spectroscopy at Brigham and Women's Hospital in Boston. "However, blows to the head suffered by all athletes involved in contact sports are of increasing concern."

According to the Centers for Disease Control and Prevention, an estimated 3.8 million sports- and recreation-related concussions occur in the U.S. each year. In addition, subclinical concussions -- injuries that cannot be diagnosed as concussions but have similar effects -- are often unrecognized.

Studies have shown that individuals who suffer repetitive brain trauma are more likely to experience ongoing problems, from permanent brain damage to long-term disability.

CTE is a degenerative brain disease caused by repeated brain trauma and marked by a buildup of abnormal proteins in the brain. CTE has been associated with memory difficulty, impulsive and erratic behavior, depression and eventually, dementia.

"Cumulative head trauma invokes changes in the brain, which over time can result in a progressive decline in memory and executive functioning in some individuals," Dr. Lin said. "MRS may provide us with noninvasive, early detection of CTE before further damage occurs, thus allowing for early intervention."

In Dr. Lin's study, conducted in collaboration with the Boston University Center for the Study of Traumatic Encephalopathy (CSTE), five retired professional male athletes from football, wrestling and boxing with suspected CTE and five age- and size-matched controls between the ages of 32 and 55 were examined with MRS. In MRS, sometimes referred to as "virtual biopsy," a powerful magnetic field and radio waves are used to extract information about chemical compounds within the body, using a clinical MR scanner.

The results revealed that compared with the brains of the control patients, the brains of the former athletes with suspected CTE had increased levels of choline, a cell membrane nutrient that signals the presence of damaged tissue, and glutamate/glutamine, or Glx. MRS also revealed altered levels of gamma-aminobutyric acid (GABA), aspartate, and glutamate in the brains of former athletes.

"By helping us identify the neurochemicals that may play a role in CTE, this study has contributed to our understanding of the pathophysiology of the disorder," Dr. Lin said.

For example, the amino acid and neurotransmitter glutamate is involved in most aspects of normal brain function and must be present in the right places and at the right concentration in order for the brain to be healthy -- too much or too little can be harmful.

"Being able to diagnose CTE could help athletes of all ages and levels, as well as war veterans who suffer mild brain injuries, many of which go undetected," Dr. Lin said.

Results of CSTE neuropathological studies of retired football players and other athletes have led to significant changes in the NFL, as well as collegiate and youth sports. Recently, the researchers found evidence of CTE in 21-year-old Owen Thomas, the University of Pennsylvania football captain who committed suicide in April 2010.

Coauthors are Saadallah Ramadan, Ph.D., Hayden Box, B.S., Peter Stanwell, Ph.D., and Robert Stern, Ph.D. Dr. Lin's research team is led by Carolyn Mountford, D.Phil. Other collaborators include Ann McKee, M.D., Robert Cantu, M.D., and Christopher Nowinski.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided byRadiological Society of North America.

Tiny Laser Light Show Illuminates Quantum Computing

2010-12-07T08:21:00.000-08:00

In theory, quantum computers will be able to solve very complex and important problems if their basic elements,

This work was funded by the Army Research Office, the Intelligence Advanced Research Projects Activity (IARPA), and the National Science Foundation.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by American Institute of Physics, via EurekAlert!, a service of AAAS.

Lower Power Consumption for Electronics: Thin Film Packaged MEMS Resonator With Industry Record Q Factor and Low Bias Voltage

2010-12-07T08:19:00.000-08:00

Panasonic and imec present at the International Electron Devices Meeting in San Francisco an innovative SiGe (silicon germanium) thin film packaged SOI-based MEMS resonator featuring an industry-record Q factor combined with a low bias voltage. The high Q factor was achieved by implementing a resonator that operates in a torsional vibration mode, and, by vacuum encapsulation of the resonator in a thin film package.

This groundbreaking resonator paves the way towards miniaturization and low power consumption of timing devices used in a variety of applications such as consumer electronics and automotive electronics.

MEMS resonators offer enhanced miniaturization over conventional resonators such as quartz crystals and

piezoelectric ceramics. However, state-of-the art MEMS resonators suffer from a low Q factor and a high bias voltage. Panasonic and imec developed a novel packaged MEMS resonator achieving the highest Q factor reported in the industry until now (220,000 at a resonant frequency f=20MHz (f•Q product of 4.3X10¹²Hz)) and low bias voltage by combining different advanced MEMS technologies.

The application of a torsional vibration mode enables low anchor losses and lower squeeze film damping compared to flexural mode resonators, resulting in a higher Q factor. Since the Q factor also depends on the ambient pressure and starts to decrease above a critical pressure due to viscous and squeeze film damping, imec and Panasonic vacuum encapsulated the resonator in a hermetically sealed environment. This thin-film encapsulation of the MEMS with a 4µm thick SiGe film is realized with a monolithic fabrication process with the MEMS.

The narrow 130nm gap between the beam and drive and sense electrodes enables a low bias voltage (1.8Vdc) and thus eliminates a charge pump in the oscillator circuit. Moreover, using sacrificial layer etching through a microcrystalline silicon germanium layer minimizes the chances of deposition of the sealing material inside the cavity and thus enables to position the etching holes right above the beam surface, leading to a smaller chip size.

The packaged MEMS resonator was realized as part of imec's CMORE service which offers heterogeneous integration services to the industry. Imec builds on its expertise in many research areas to tune and extend CMOS processes with new processing steps to make novel CMOS micro- and nanodevices, adding functions other than logic and memory to the chips. Possible applications of such MEMS devices are smart sensors, actuators, power scavengers, resonators, biochips, micro-implantable appliances, or solar cells. Imec's CMORE services range from development-on-demand, over prototyping, to low-volume production.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided byInteruniversity Microelectronics Centre (IMEC), viaAlphaGalileo.

Dark Matter Could Transfer Energy in the Sun

2010-12-07T08:16:00.000-08:00

Researchers from the Institute for Corpuscular Physics (IFIC) and other European groups have studied the effects of the presence of dark matter in the Sun. According to their calculations, low mass dark matter particles could be transferring energy from the core to the external parts of the Sun, which would affect the quantity of neutrinos that reach Earth.

"We assume that the dark matter particles interact weakly with the Sun's atoms, and what we have done is calculate at what level these interactions can occur, in order to better describe the structure and evolution of the Sun," Marco Taoso, researcher at the IFIC, a combined centre of the Spanish National Research Council and the University of Valencia, explains.

The astrophysical observations suggest that our galaxy is situated in a halo of dark matter particles. According to the models, some of these particles, the WIMPs (Weakly Interacting Massive Particles) interact weakly with other normal ones, such as atoms, and could be building up on the inside of stars. The study, recently published in the journal Physical Review D, carries out an in-depth study of the case of the Sun in particular.

"When the WIMPs pass through the Sun they can break up the atoms of our star and lose energy. This prevents them from escaping the gravitational force of the Sun which captures them, and they become trapped, orbiting inside it, with no way of escaping," the researcher points out.

The dark matter cools down the Sun's core

Scientists believe that the majority of the dark matter particles gather together in the centre of the Sun, but in their elliptic orbits they also travel to the outer part, interacting and exchanging with the solar atoms. In this way, the WIMPs transport the energy from the burning central core to the cooler peripheral parts.

"This effect produces a cooling down of the core, the region from where the neutrinos originate due to the nuclear reactions of the Sun," Taoso points out. "And this corresponds to a reduction in the flux of solar neutrinos, since these depend greatly on the temperature of the core."

The neutrinos that reach Earth can be measured by means of different techniques. These data can be used to detect the modifications of the solar temperature caused by the WIMPs. The transport of energy by these particles depends on the likelihood of them interacting with the atoms, and the "size" of these interactions is related to the reduction in the neutrino flux.

"As a result, current data about solar neutrinos can be used to put limits on the extent of the interactions between dark matter and atoms, and using numerical codes we have proved that certain values correspond to a reduction in the flux of solar neutrinos and clash with the measurements," the scientist reveals.

The team has applied their calculations to better understand the effects of low mass dark matter particles (between 4 and 10 gigaelectronvolts). At this level we find models that attempt to explain the results of experiments such as DAMA (beneath an Italian mountain) or CoGent (in a mine in the USA), which look for dark material using "scintillators" or WIMP detectors.

Debate about WIMP and solar composition

This year another study by scientists from Oxford University (United Kingdom) also appeared. It states that WIMPs not only reduce the fluxes of solar neutrinos, but also, furthermore, modify the structure of the Sun and can explain its composition.

"Our calculations, however, show that the modifications of the star's structure are too small to support this claim and that the WIMPs cannot explain the problem of the composition of the sun," Taoso concludes.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Plataforma SINC, via AlphaGalileo.

Satellite Tracking Campaign Tests European Abilities

2010-12-07T08:15:00.000-08:00

An experimental tracking campaign using European facilities is helping determine how well existing telescopes and radars can work together to observe objects in Earth orbit. The results will be used to help design ESA's future Space Situational Awareness system.

On 29 November, experts from the Agency's Space Situational Awareness (SSA) Preparatory Programme began an experimental tracking campaign using scientific research telescopes and radars in five European countries. The campaign is testing how well existing facilities can track potential debris hazards in orbit using known satellites as targets.

A series of three overnight tests during November to February will see the radars and telescopes being used to

track a dozen candidate 'objects' -- existing satellites including ESA's GOCE, Artemis and Envisat. Other European satellite operators, including Eumetsat and SES-Astra, have agreed to the use of their satellites in the tracking campaign as well.

Facilities in Sweden, UK, Switzerland, Spain and Cyprus

To track objects in low orbit -- just several hundred kilometres altitude -- the campaign is making use of research radars operated by the European Incoherent Scatter Scientific Association (EISCAT) in Sweden and Norway, and by the Chilbolton Observatory in Hampshire, UK.

For objects in geostationary orbit -- up to 36 000 km altitude -- the tests will use optical telescopes, including ESA's own Optical Ground Station in Tenerife, Spain.

In addition, astronomical observatories in Spain (Observatorio Astronómico de Mallorca), Switzerland (Zimmerwald Observatory) and Troodos, Cyprus (British National Space Centre -- Starbrook) will be used.

Testing diverse sensors for interoperability

Some of the radars and telescopes were originally designed for meteorological, ionospheric or astronomical studies, so their use for tracking objects in Earth orbit is complementary but has not been fully tested.

"A significant goal of the campaign is determining how well these facilities can provide tracking data and identifying any operational problems related to, for example, weather or interoperability issues," says Emmet Fletcher, Head of the Space Surveillance and Tracking (SST) Segment at ESA's SSA programme.

Fletcher says that knowing how a diverse network of independent sensors can work together is critical for designing the architecture of the future European hazard-tracking system.

Results from the campaign will be used to assess the potential performance of the current European infrastructure, and how the future SST tracking capability should be designed to best make use of such assets.

About Europe's space hazard tracking capability

Under the SSA Preparatory Programme, a main aim of the SST element is to provide an independent ability to promptly acquire and catalogue precise information on objects orbiting Earth. Using these data, a wide range of services will be provided by the future European SSA System, such as warning of potential collisions and alerting when and where debris reenters Earth's atmosphere. These data will be stored in a catalogue and made available to SSA customers across Europe.

The infrastructure required to provide these capabilities is referred to as the ''SST Segment'. It comprises surveillance and tracking sensors, which could use radar or optical technology, to acquire raw data, which are then processed to correlate (or link) each observed object with ones already known, or to indicate a new object.

Initially, the SST Segment will obtain data using existing sensors. When the full SSA programme begins, additional systems may be developed and deployed as required to achieve the objective of European autonomy in this area. The decision for the continuation of the SSA Programme is planned to be taken at the next ESA Ministerial Council, foreseen in 2012.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by European Space Agency, via AlphaGalileo.

Stripes Are Back in Season on Jupiter

2010-12-07T08:13:00.000-08:00

New NASA images support findings that one of Jupiter's stripes that "disappeared" last spring is now showing signs of a comeback. These new observations will help scientists better understand the interaction between Jupiter's winds and cloud chemistry.

Earlier this year, amateur astronomers noticed that a longstanding dark-brown stripe, known as the South Equatorial Belt, just south of Jupiter's equator, had turned white. In early November, amateur astronomer Christopher Go of Cebu City, Philippines, saw an unusually bright spot in the white area that was once the dark stripe. This phenomenon piqued the interest of scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and elsewhere.

After follow-up observations in Hawaii with NASA's Infrared Telescope Facility, the W.M. Keck Observatory and the Gemini Observatory telescope, scientists now believe the vanished dark stripe is making a comeback.

First-glimpse images of the re-appearing stripe are online at:http://www.nasa.gov/topics/solarsystem/features/jupiter20101124-i.html.

"The reason Jupiter seemed to 'lose' this band -- camouflaging itself among the surrounding white bands -- is that the usual downwelling winds that are dry and keep the region clear of clouds died down," said Glenn Orton, a research scientist at JPL. "One of the things we were looking for in the infrared was evidence that the darker material emerging to the west of the bright spot was actually the start of clearing in the cloud deck, and that is precisely what we saw."

This white cloud deck is made up of white ammonia ice. When the white clouds float at a higher altitude, they obscure the missing brown material, which floats at a lower altitude. Every few decades or so, the South Equatorial Belt turns completely white for perhaps one to three years, an event that has puzzled scientists for decades. This extreme change in appearance has only been seen with the South Equatorial Belt, making it unique to Jupiter and the entire solar system.

The white band wasn't the only change on the big, gaseous planet. At the same time, Jupiter's Great Red Spot became a darker red color. Orton said the color of the spot -- a giant storm on Jupiter that is three times the size of Earth and a century or more old -- will likely brighten a bit again as the South Equatorial Belt makes its comeback.

The South Equatorial Belt underwent a slight brightening, known as a "fade," just as NASA's New Horizons spacecraft was flying by on its way to Pluto in 2007. Then there was a rapid "revival" of its usual dark color three to four months later. The last full fade and revival was a double-header event, starting with a fade in 1989, revival in 1990, then another fade and revival in 1993. Similar fades and revivals have been captured visually and photographically back to the early 20th century, and they are likely to be a long-term phenomenon in Jupiter's atmosphere.

Scientists are particularly interested in observing this latest event because it's the first time they've been able to use modern instruments to determine the details of the chemical and dynamical changes of this phenomenon. Observing this event carefully may help to refine the scientific questions to be posed by NASA's Juno spacecraft, due to arrive at Jupiter in 2016, and a larger, proposed mission to orbit Jupiter and explore its satellite Europa after 2020.

The event also signifies another close collaboration between professional and amateur astronomers. The amateurs, located worldwide, are often well equipped with instrumentation and are able to track the rapid developments of planets in the solar system. These amateurs are collaborating with professionals to pursue further studies of the changes that are of great value to scientists and researchers everywhere.

"I was fortunate to catch the outburst," said Christopher Go, referring to the first signs that the band was coming back. "I had a meeting that evening and it went late. I caught the outburst just in time as it was rising. Had I imaged earlier, I would not have caught it," he said. Go, who also conducts in the physics department at the University of San Carlos, Cebu City, Philippines, witnessed the disappearance of the stripe earlier this year, and in 2007 he was the first to catch the stripe's return. "I was able to catch it early this time around because I knew exactly what to look for."

NASA's Exoplanet Science Institute at the California Institute of Technology in Pasadena manages time allocation on the Keck telescope for NASA. Caltech manages JPL for NASA.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by NASA/Jet Propulsion Laboratory.

Self-Healing Autonomous Material Comes to Life

2010-12-07T08:10:00.001-08:00

You've seen it in movies: the human-like, robot assassin quickly regenerates its structure after being damaged beyond recognition. This "Terminator" scenario is becoming less far-fetched as recent advances in structural health monitoring systems have led to a variety of ways to identify damage to a structural system.

Now, in the Journal of Applied Physics, researchers at Arizona State University have created a material that may be able to not only sense damage in structural materials, such as cracking in a fiber-reinforced composite, but to even heal it. The aim of developing "autonomous adaptive structures" is to mimic the ability of biological systems such as bone to sense the presence of damage, halt its progression, and regenerate itself.

The novel autonomous material developed by Henry Sodano and colleagues uses "shape-memory" polymers with an embedded fiber-optic network that functions as both the damage detection sensor and thermal stimulus delivery system to produce a response that mimics the advanced sensory and healing traits shown in biological systems. An infrared laser transmits light through the fiber-optic system to locally heat the material, stimulating the toughening and healing mechanisms.

The material system is capable of increasing the toughness of a specimen by 11 times. After toughening the specimen, the crack can be closed using the shape-memory effect to recover an unprecedented 96 percent of the object's original strength. In fact, after the crack is closed, the new material is nearly five times as tough as the original specimen, even though it has been strained past its original failure strain point by a factor of four. The material and healing process can be applied while the structure is in operation, which has not been possible with existing healing techniques.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by American Institute of Physics, via EurekAlert!, a service of AAAS.

Nanosatellite Successfully Ejected from Free-Flying Microsatellite in Space

2010-12-07T03:18:00.001-08:00

On Dec. 6 at 1:31 a.m. EST, NASA for the first time successfully ejected a nanosatellite from a free-flying microsatellite. NanoSail-D ejected from the Fast, Affordable, Science and Technology Satellite, FASTSAT, demonstrating the capability to deploy a small cubesat payload from an autonomous microsatellite in space.

Nanosatellites or cubesats are typically launched and deployed from a mechanism called a Poly-PicoSatellite Orbital Deployer (P-POD) mounted directly on a launch vehicle. This is the first time NASA has mounted a P-POD

on a microsatellite to eject a cubesat.

FASTSAT, equipped with six science and technology demonstration payloads, including NanoSail-D, launched Friday, Nov. 19 at 8:25 p.m. EST from Kodiak Island, Alaska. During launch, the NanoSail-D flight unit, about the size of a loaf of bread, was stowed inside FASTSAT in a P-POD.

"The successful ejection of NanoSail-D demonstrates the operational capability of FASTSAT as a cost-effective independent means of placing cubesat payloads into orbit safely," said Mark Boudreaux, FASTSAT project manager at the Marshall Space Flight Center in Huntsville, Ala. "With this first step behind us, we have demonstrated we can launch a number of different types of payloads using this common deployment system from an autonomous microsatellite like FASTSAT."

"NanoSail D has multiple enabling technology demonstration objectives for this flight," said Joe Casas, FASTSAT project scientist at Marshall. Casas said when the NanoSail-D sail is deployed it will use its large sail made of thin polymer material, a material much thinner than a single human hair, to significantly decrease the time to de-orbit the small satellite without the use of propellants as most traditional satellites use.

The NanoSail-D flight results will help to mature this technology so it could be used on future large spacecraft missions to aid in de-orbiting space debris created by decommissioned satellites without using valuable mission propellants.

"This is a great step for our solar sail team with the successful ejection of the NanoSail-D satellite from FASTSAT," said Dean Alhorn, NanoSail-D principal investigator and aerospace engineer at the Marshall Center. "We had to carefully plan and calculate the ejection time, so we'd be lined up over the United States and our ground controllers to execute the next phase of the mission."

After ejection, a timer within NanoSail-D will begin a three day countdown as the satellite orbits the Earth. Once the timer reaches zero, four booms will quickly deploy and the NanoSail-D sail will start to unfold to a 100 square foot polymer sail. Within five seconds the sail fully unfurls.

If the deployment is successful, NanoSail-D will stay in low-Earth orbit between 70 and 120 days, depending on atmospheric conditions. NanoSail-D is designed to demonstrate deployment of a compact solar sail boom system that could lead to further development of this alternative solar sail propulsion technology and FASTSAT's ability to eject a nanosatellite from a microsatellite -- while avoiding re-contact with the FASTSAT satellite bus.

NanoSail-D was designed and built by engineers in Huntsville and managed at the Marshall Center with technical and hardware support from NASA's Ames Research Center in Moffett Field, Calif. This experiment is a combined effort between the Space and Missile Defense Command, Von Braun Center for Science and Innovation, both located in Huntsville, Ala. and NASA.

FASTSAT launched on the STP-S26 mission -- a joint activity between NASA and the U.S. Department of Defense Space Test Program. The satellite was designed, developed and tested at the Marshall Center in partnership with the Von Braun Center for Science & Innovation and Dynetics Inc. of Huntsville. Dynetics provided key engineering, manufacturing and ground operations support for the new microsatellite. Thirteen Huntsville-area firms, as well as the University of Alabama in Huntsville, also were part of the project team.

To learn more about FASTSAT and the NanoSail-D missions visit: http://www.nasa.gov/mission_pages/smallsats

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided byNASA/Marshall Space Flight Center.

Threshold Sea Surface Temperature for Hurricanes and Tropical Thunderstorms Is Rising

2010-12-07T03:16:00.001-08:00

Scientists have long known that atmospheric convection in the form of hurricanes and tropical ocean thunderstorms tends to occur when sea surface temperature rises above a threshold. The critical question is, how do rising ocean temperatures with global warming affect this threshold? If the threshold does not rise, it could mean more frequent hurricanes.

According to a new study by researchers at the International Pacific Research Center (IPRC) of the University of Hawaii at Manoa (UHM), this threshold sea surface temperature for convection is rising under global warming at the same rate as that of the tropical oceans.

Their paper appears in the journalNature Geoscience.

In order to detect the annual changes in the threshold sea surface temperature, Nat Johnson, a postdoctoral fellow at IPRC, and Shang-Ping Xie, a professor of meteorology at IPRC and UHM, analyzed satellite estimates of

tropical ocean rainfall spanning 30 years. They find that changes in the threshold temperature for convection closely follow the changes in average tropical sea surface temperature, which have both been rising approximately 0.1°C per decade.

"The correspondence between the two time series is rather remarkable," says lead author Johnson. "The convective threshold and average sea surface temperatures are so closely linked because of their relation with temperatures in the atmosphere extending several miles above the surface."

The change in tropical upper atmospheric temperatures has been a controversial topic in recent years because of discrepancies between reported temperature trends from instruments and the expected trends under global warming according to global climate models. The measurements from instruments have shown less warming than expected in the upper atmosphere. The findings of Johnson and Xie, however, provide strong support that the tropical atmosphere is warming at a rate that is consistent with climate model simulations.

"This study is an exciting example of how applying our knowledge of physical processes in the tropical atmosphere can give us important information when direct measurements may have failed us," Johnson notes.

The study notes further that global climate models project that the sea surface temperature threshold for convection will continue to rise in tandem with the tropical average sea surface temperature. If true, hurricanes and other forms of tropical convection will require warmer ocean surfaces for initiation over the next century.

This work was supported by grants from NOAA, NSF, NASA, and JAMSTEC.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Hawaii at Manoa.

Pregnant Mother's Diet Impacts Infant's Sense of Smell, Alters Brain Development

2010-12-07T03:15:00.001-08:00

A major new study shows that a pregnant mother's diet not only sensitizes the fetus to those smells and flavors, but physically changes the brain directly impacting what the infant eats and drinks in the future.

"This highlights the importance of eating a healthy diet and refraining from drinking alcohol during pregnancy and nursing," said Josephine Todrank, PhD, who conducted the two-year study while a visiting scientist at the University of Colorado School of Medicine. "If the mother drinks alcohol, her child may be more attracted to

alcohol because the developing fetus "expects" that whatever comes from the mother must be safe. If she eats healthy food, the child will prefer healthy food."

Researchers studying mice found that the pups' sense of smell is changed by what their mothers eat, teaching them to like the flavors in her diet. At the same time, they found significant changes in the structure of the brain's olfactory glomeruli, which processes smells, because odors in the amniotic fluid affect how this system develops.

"This is the first study to address the changes in the brain that occur upon steady exposure to flavors in utero and early in postnatal life when the newborn is receiving milk from the mother," said Diego Restrepo, PhD, co-director of the Center for NeuroScience at the University of Colorado School of Medicine and sponsor of the study. "During these periods the pup is exposed to flavors found in the food the mom is eating."

The research, he said, could have important public health implications.

"Many diseases plaguing society involve excess consumption or avoidance of certain kinds of foods," said Restrepo, a professor of cell and developmental biology. "Understanding the factors that determine choice and ingestion, particularly the early factors, is important in designing strategies to enhance the health of the infant, child, and adult."

In her study, Todrank, now a research fellow with collaborator Giora Heth, PhD, at the Institute of Evolution at the University of Haifa, Israel, fed one group of pregnant and nursing mice a bland diet and another a flavored diet. At weaning age, the pups from mothers on the flavored diet had significantly larger glomeruli than those on the bland diet. They also preferred the same flavor their mother ate, while the other pups had no preference.

"Exposure to odor or flavor in the womb elicits the preference but also shapes the brain development," said Todrank, whose work was funded by a grant from the National Institutes of Health and was published Dec. 1, 2010 in the Proceedings of the Royal Society B.

"From the fetus' point of view, whatever is in the womb is considered "good." If your mother ate it and survived to give birth to you then it was probably safe," she said. "This is a good strategy for a mouse that is foraging for food. It treats those same foods as safe."

Due to the similarities in mammalian development, she said, there is no reason to think that experiments would produce different results in humans.

"What an expectant mother chooses to eat and drink has long-term effects -- for better or worse -- on her child's sensory anatomy as well his or her odor memory and food preferences in the future," Todrank said. "It is not yet clear how long these changes and preferences last, but we are currently investigating that question."

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Colorado Denver.

First Horned Dinosaur from South Korea Discovered

2010-12-07T03:14:00.000-08:00

Scientists from South Korea, the United States and Japan analyzed fossil evidence found in South Korea and published research describing a new horned dinosaur. The newly identified genus, Koreaceratops hwaseongensis, lived about 103 million years ago during the late Early Cretaceous period. The specimen is the first ceratopsian dinosaur from the Korean peninsula. The partial skeleton includes a significant portion of the animal's backbone, hip bone, partial hind limbs and a nearly complete tail.

Results from the analysis of the specimen were published in the 18 November 2010 online edition of the journal Naturwissenchaften: The Science of Nature.

The Koreaceratops hwaseongensis is named for Korea and Hwaseong City, which yielded the fossil. It was discovered in 2008 in a block of rock along the Tando Basin reservoir. It is one of the first articulated dinosaurs known from Korea.

"This is a rare find," said Michael J. Ryan, Ph.D., curator and head of Vertebrate Paleontology at The Cleveland Museum of Natural History, who co-authored the research. "Fossils of dinosaurs have not typically been found in this region, whereas evidence of dinosaur eggs and footprints occur more commonly. This specimen is significant because it fills in a missing 20 million-year gap in the fossil record between the origin of these dinosaurs in Asia and their first appearance in North America."

At approximately 5 to 6 feet long and weighing about 60 to 100 pounds, the animal was relatively small compared to the geologically younger, giant relatives like Triceratops found in North America. Koreaceratops had a parrot-like face with a beak at the front of its jaws, indicating it was an herbivore. The claws on its hind feet suggest that it was bipedal and moved at a fairly rapid speed. Koreaceratops had a unique fan-shaped tail formed by long neural spines, which suggests it may have been a good swimmer, and spent part of its time hunting for aquatic food.

Yuong-Nam Lee of the Korea Institute of Geoscience and Mineral Resources was lead author on the research. Yoshitsugu Kobayashi of the Hokkaido University Museum in Japan was third author.

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The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Cleveland Museum of Natural History, via EurekAlert!, a service of AAAS