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2013-12-13

Noble gas molecule discovered in space

Dec. 12, 2013 — A molecule containing a noble gas has been discovered in space by a team including astronomers from Cardiff University.

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The find was made using a Cardiff-led instrument aboard Europe's Herschel Space Observatory. The molecule, argon hydride, was seen in the Crab Nebula, the remains of a star that exploded 1,000 years ago. Before the discovery, molecules of this kind have only been studied in laboratories on Earth.

The noble gases, which include helium, argon, radon and krypton, usually do not react easily with other chemical elements, and are often found on their own. In the right circumstances, however, they can form molecules with other elements. Such chemical compounds have only ever been studied in laboratories on Earth, leading astronomers to assume the right conditions simply do not occur in space.

"The Crab Nebula was only formed 1000 years ago when a massive star exploded," said Dr Haley Gomez of Cardiff University's School of Physics and Astronomy. "Not only is it very young in astronomical terms, but also relatively close, at just 6,500 light years away, providing an excellent way to study what happens in these stellar explosions. Last year, we used the European Space Agency's Herschel Space Observatory to study the intricate network of gas filaments to show how exploding stars are creating huge amounts of space dust."

Further measurements of the Crab Nebula were made using Herschel's SPIRE instrument. Its development and operation was led by Professor Matt Griffin, from the School of Physics and Astronomy. As molecules spin in space, they emit light of very specific wavelengths, or colours, called "emission lines." The precise wavelength is dictated by the composition and structure of the molecule. Studying the emission lines observed by the SPIRE instrument allows astronomers to study the chemistry of outer space.

The team, led by Professor Mike Barlow from University College London, did not set out to make the discovery, but stumbled upon it almost by accident. "We were really concentrating on studying the dust in the filaments with SPIRE, and out pops these two bright emission lines exactly where we see the dust shining," says Dr Gomez. "The team had a hard time figuring out what these lines were from, as no-one had seen them before."

Professor Barlow said, "At first, the discovery of argon seemed bizarre. With hot gas still expanding at high speeds after the explosion, a supernova remnant is a harsh, hot and hostile environment, and one of the places where we least expected to find a noble-gas based molecule."

It now seems the Crab Nebula provides exactly the right conditions to form such molecules. The argon was produced in the initial stellar explosion, and then ionised, or energised, with electrons stripped from the atoms in resulting intense radiation as shockwaves. These shockwaves led to the formation of the network of cool filaments containing cold molecular hydrogen, made of two hydrogen atoms. The ionised argon then mixed with the cool gas to provide perfect conditions for noble gas compounds to form.

The measurements allowed the team to gauge other properties in argon molecules. "Finding this kind of molecule allowed us to evaluate the type (or isotope) of argon we discovered in the Crab Nebula," said Dr Gomez. "We now know that it is different from argon we see in rocks on the Earth. Future measurements will allow us to probe what exactly took place in the explosion 1000 years ago."

"What a great detective story," added Prof Matt Griffin, from Cardiff University, and lead scientist of the team behind the SPIRE instrument. "Here we see the excellent performance of the Herschel-SPIRE spectrometer, the expertise of the instrument team in producing the highest quality data, and the tenacity and vision of the scientists analysing it, all coming together to make an intriguing new discovery."

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Aquatic comb jelly floats into new evolutionary position

The cornerstone of the study, published in the Dec. 13, 2013, advance online issue of Science, is the researchers' sequencing, assembly, annotation and analysis of the genome of Mnemiopsis leidyi, a comb jelly native to the coastal waters of the western Atlantic Ocean. Whole-genome sequencing data shows that comb jellies branched from the rest of the animals before the sponge, a simple animal without complex cell types, according to the study. The results also show that critical cell types, such as neurons and muscle cells, were either lost multiple times during evolution or evolved independently in the ctenophores.

For the past 30 years, researchers have used whole-genome sequencing of organisms to advance their understanding of evolution. They do this by comparing the order of the chemical bases of DNA -- 150 million base pairs for comb jellies versus 3 billion in humans -- that comprise the organism's genome. While whole-genome sequencing data have been available for four of the five major animal lineages -- sponges (Porifera), flat invertebrates (Placozoa), jellyfish (Cnidaria), and animals with left-right symmetry, including humans (Bilateria) -- Ctenophora remained the last major animal lineage for which there were no sequenced genomes.

"Having genomic data from the ctenophores is crucial from a comparative genomics perspective, since it allows us to determine what physical and structural features were present in animals early on," said Andy Baxevanis, Ph.D., senior author of the study and senior scientist in NHGRI's Division of Intramural Research. "These data also provide us an invaluable window for determining the order of events that led to the incredible diversity that we see in the animal kingdom."

Comb jellies possess muscle cells, but the analysis of the Mnemiopsis genome showed that comb jellies lack the vast majority of genes that specify muscle types in most other animals. According to the researchers, the absence of such a large number of muscle genes suggests that muscle cells evolved independently in comb jellies, after they diverged from the rest of the animals. Comb jellies also possess a simple form of nervous system, called a nerve net, and their genome contains many of the genes involved in the nervous system. Sponges also have these genes, suggesting that they may have had the capacity to support a nervous system and perhaps lost it.

The results of the study lead to a new way of thinking about early animal evolution. "Our analysis of the Mnemiopsis genome thoroughly corroborates previous studies suggesting that ctenophores might be the sister group to the rest of the animals," said Joseph Ryan, Ph.D., lead author and a former postdoctoral research fellow in NHGRI's Genome Technology Branch, now at the Sars International Center for Marine Molecular Biology, University of Bergen, Norway. "With our whole-genome sequencing data in hand, it is now clear that the cell types that make up muscles and nervous systems were either lost in some animal lineages or that, despite the complexity of these cells, they very well may have evolved multiple times."

"Expanding our understanding of genomes across the animal kingdom is important for gaining an understanding of evolutionary adaptation at the molecular, cellular and organismal levels," said Daniel Kastner, M.D., Ph.D., NHGRI scientific director. "The whole-genome sequence of the comb jelly provides a nontraditional model through which new insights about genes and their functions, including those in our own genome, may become better understood."

The study involved collaborators from the Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, Fl.; Brown University, Providence, R.I.; the Monterey Bay Aquarium Research Institute, Moss Landing, Calif.; Rice University, Houston; the University of Michigan, Ann Arbor; and the NIH Intramural Sequencing Center (NISC), Rockville, Md.

"Our study demonstrates the power of comparative genomics research having an evolutionary point of view, probing the interface of genomics and developmental biology," said co-author Jim Mullikin, Ph.D., NISC director. "The data generated in the course of this study also provide a strong foundation for future work that will undoubtedly lead to novel findings related to the nature of animal biology."

"Over the longer term, basic biological discoveries made in organisms such as Mnemiopsis could very well lay the groundwork for translational studies focused on specific human diseases," said Dr. Baxevanis.

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Sniffing out danger: Fearful memories can trigger heightened sense of smell

Dec. 12, 2013 — Most people -- including scientists -- assumed we can't just sniff out danger.

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It was thought that we become afraid of an odor -- such as leaking gas -- only after information about a scary scent is processed by our brain.

But neuroscientists at Rutgers University studying the olfactory -- sense of smell -- system in mice have discovered that this fear reaction can occur at the sensory level, even before the brain has the opportunity to interpret that the odor could mean trouble.

In a new study published today in Science, John McGann, associate professor of behavioral and systems neuroscience in the Department of Psychology, and his colleagues, report that neurons in the noses of laboratory animals reacted more strongly to threatening odors before the odor message was sent to the brain.

"What is surprising is that we tend to think of learning as something that only happens deep in the brain after conscious awareness," says McGann. "But now we see how the nervous system can become especially sensitive to threatening stimuli and that fear-learning can affect the signals passing from sensory organs to the brain."

McGann and students Marley Kass and Michelle Rosenthal made this discovery by using light to observe activity in the brains of genetically engineered mice through a window in the mouse's skull. They found that those mice that received an electric shock simultaneously with a specific odor showed an enhanced response to the smell in the cells in the nose, before the message was delivered to the neurons in the brain.

This new research -- which indicates that fearful memories can influence the senses -- could help to better understand conditions like Post Traumatic Stress Disorder, in which feelings of anxiety and fear exist even though an individual is no longer in danger.

"We know that anxiety disorders like PTSD can sometimes be triggered by smell, like the smell of diesel exhaust for a soldier," says McGann who received funding from the National Institute of Mental Health and the National Institute on Deafness and Other Communication Disorders for this research. "What this study does is gives us a new way of thinking about how this might happen."

In their study, the scientists also discovered a heightened sensitivity to odors in the mice traumatized by shock. When these mice smelled the odor associated with the electrical shocks, the amount of neurotransmitter -- chemicals that carry communications between nerve cells -- released from the olfactory nerve into the brain was as big as if the odor were four times stronger than it actually was.

This created mice whose brains were hypersensitive to the fear-associated odors. Before now, scientists did not think that reward or punishment could influence how the sensory organs process information.

The next step in the continuing research, McGann says, is to determine whether the hypersensitivity to threatening odors can be reversed by using exposure therapy to teach the mice that the electrical shock is no longer associated with a specific odor. This could help develop a better understanding of fear learning that might someday lead to new therapeutic treatments for anxiety disorders in humans, he says.

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Programming smart molecules: Machine-learning algorithms could make chemical reactions intelligent

Dec. 12, 2013 — Computer scientists at the Harvard School of Engineering and Applied Sciences (SEAS) and the Wyss Institute for Biologically Inspired Engineering at Harvard University have joined forces to put powerful probabilistic reasoning algorithms in the hands of bioengineers.

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In a new paper presented at the Neural Information Processing Systems conference on December 7, Ryan P. Adams and Nils Napp have shown that an important class of artificial intelligence algorithms could be implemented using chemical reactions.

These algorithms, which use a technique called "message passing inference on factor graphs," are a mathematical coupling of ideas from graph theory and probability. They represent the state of the art in machine learning and are already critical components of everyday tools ranging from search engines and fraud detection to error correction in mobile phones.

Adams' and Napp's work demonstrates that some aspects of artificial intelligence (AI) could be implemented at microscopic scales using molecules. In the long term, the researchers say, such theoretical developments could open the door for "smart drugs" that can automatically detect, diagnose, and treat a variety of diseases using a cocktail of chemicals that can perform AI-type reasoning.

"We understand a lot about building AI systems that can learn and adapt at macroscopic scales; these algorithms live behind the scenes in many of the devices we interact with every day," says Adams, an assistant professor of computer science at SEAS whose Intelligent Probabilistic Systems group focuses on machine learning and computational statistics. "This work shows that it is possible to also build intelligent machines at tiny scales, without needing anything that looks like a regular computer. This kind of chemical-based AI will be necessary for constructing therapies that sense and adapt to their environment. The hope is to eventually have drugs that can specialize themselves to your personal chemistry and can diagnose or treat a range of pathologies."

Adams and Napp designed a tool that can take probabilistic representations of unknowns in the world (probabilistic graphical models, in the language of machine learning) and compile them into a set of chemical reactions that estimate quantities that cannot be observed directly. The key insight is that the dynamics of chemical reactions map directly onto the two types of computational steps that computer scientists would normally perform in silico to achieve the same end.

This insight opens up interesting new questions for computer scientists working on statistical machine learning, such as how to develop novel algorithms and models that are specifically tailored to tackling the uncertainty molecular engineers typically face. In addition to the long-term possibilities for smart therapeutics, it could also open the door for analyzing natural biological reaction pathways and regulatory networks as mechanisms that are performing statistical inference. Just like robots, biological cells must estimate external environmental states and act on them; designing artificial systems that perform these tasks could give scientists a better understanding of how such problems might be solved on a molecular level inside living systems.

"There is much ongoing research to develop chemical computational devices," says Napp, a postdoctoral fellow at the Wyss Institute, working on the Bioinspired Robotics platform, and a member of the Self-organizing Systems Research group at SEAS. Both groups are led by Radhika Nagpal, the Fred Kavli Professor of Computer Science at SEAS and a Wyss core faculty member. At the Wyss Institute, a portion of Napp's research involves developing new types of robotic devices that move and adapt like living creatures.

"What makes this project different is that, instead of aiming for general computation, we focused on efficiently translating particular algorithms that have been successful at solving difficult problems in areas like robotics into molecular descriptions," Napp explains. "For example, these algorithms allow today's robots to make complex decisions and reliably use noisy sensors. It is really exciting to think about what these tools might be able to do for building better molecular machines."

Indeed, the field of machine learning is revolutionizing many areas of science and engineering. The ability to extract useful insights from vast amounts of weak and incomplete information is not only fueling the current interest in "big data," but has also enabled rapid progress in more traditional disciplines such as computer vision, estimation, and robotics, where data are available but difficult to interpret. Bioengineers often face similar challenges, as many molecular pathways are still poorly characterized and available data are corrupted by random noise.

Using machine learning, these challenges can now be overcome by modeling the dependencies between random variables and using them to extract and accumulate the small amounts of information each random event provides.

"Probabilistic graphical models are particularly efficient tools for computing estimates of unobserved phenomena," says Adams. "It's very exciting to find that these tools map so well to the world of cell biology."

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Physicists provide answers for predicted behavior in relaxors: Thin films studied used in electronic devices

Physicists Sergey Prosandeev and Laurent Bellaiche, with Dawei Wang at Xi'an Jiaotong University in China, report their findings in an article titled "Properties of epitaxial films made of relaxor ferroelectrics," in current issue of the journal Physical Review Letters.

Prosandeev and Bellaiche study ferroelectric materials, which convert small changes in mechanical energy into electrical energy, called a piezoelectric response, and are used in a wide range of applications that includes injectors in vehicles and heart implants.

In this study, the team used supercomputers at the Arkansas High Performance Computing Center to perform calculations on thin films made of a certain type of complex ferroelectrics -- called relaxors -- that were deposited on different substrates.

Their conclusions suggest how their properties could be controlled.

"One advantage of thin films is that they can be grown on different substrates, which makes their distance between atoms identical to those of the substrate," said Bellaiche, a Distinguished Professor of physics. "If you change the substrate, you change the distance between atoms in the films. We discovered what happens to the physical properties -- both microscopic and macroscopic -- when doing so."

The authors put forward a phase diagram that will help scientists design new transducers and other devices made of relaxor thin films, said Prosandeev, a research professor of physics.

"This study is important for experimentalists who grow piezoelectric films and look for new thin films that possess desired properties that are important for our daily life and technology," Prosandeev said. "This study opens a new direction in the understanding of the properties of disordered piezoelectric thin films."

Bellaiche holds the Twenty-First Century Endowed Professorship in Nanotechnology and Science Education. Prosandeev and Bellaiche are both in the University of Arkansas' Institute for Nanoscience and Engineering.

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New definition for old age

Dec. 12, 2013 — A groundbreaking study published in the journal Population and Development Review by IIASA population researchers Warren Sanderson and Sergei Scherbov reorients the way demographers study population aging, providing a new toolbox of methodologies for demographers to better understand the impacts of an aging population on society.

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Previously, studies of aging used only one characteristic of people, their chronological age. The new study provides a framework for measuring aging based instead on characteristics of people that change with age, including life expectancy, health, cognitive function, and other measures. These measures can be used by demographers to better understanding aging societies.

"Your true age is not just the number of years you have lived," says IIASA researcher Sergei Scherbov. "It also includes characteristics such as health, cognitive function, and disability rates."

Demographers have not traditionally used such measures in studies of population and society, instead using age as a proxy for those characteristics. But as lifespans get longer, the same age no longer correlates with the same level of health and other such characteristics.

"We use to consider people old at age 65," says Scherbov. "Today, someone who is 65 may be more like someone who was 55 forty-fifty years ago in terms of many important aspects of their lives."

The authors show that policy recommendations with respect to aging differ depending on exactly which characteristics of people are measured. "For different purposes we need different measures. Aging is multidimensional," says Scherbov. By reconceptualizing population aging to incorporate how people actually function, the study provides the foundation of a much richer and more realistic view of population aging.

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Hubble Space Telescope sees evidence of water vapor venting off Jupiter moon

Previous scientific findings from other sources already point to the existence of an ocean located under Europa's icy crust. Researchers are not yet fully certain whether the detected water vapor is generated by erupting water plumes on the surface, but they are confident this is the most likely explanation.

Should further observations support the finding, this would make Europa the second moon in the solar system known to have water vapor plumes. The findings are being published in the Dec. 12 online issue of Science Express, and reported at the meeting of the American Geophysical Union in San Francisco.

"By far the simplest explanation for this water vapor is that it erupted from plumes on the surface of Europa," said lead author Lorenz Roth of Southwest Research Institute in San Antonio. "If those plumes are connected with the subsurface water ocean we are confident exists under Europa's crust, then this means that future investigations can directly investigate the chemical makeup of Europa's potentially habitable environment without drilling through layers of ice. And that is tremendously exciting."

In 2005, NASA's Cassini orbiter detected jets of water vapor and dust spewing off the surface of Saturn's moon Enceladus. Although ice and dust particles have subsequently been found in the Enceladus plumes, only water vapor gases have been measured at Europa so far.

Hubble spectroscopic observations provided the evidence for Europa plumes in December 2012. Time sampling of Europa's auroral emissions measured by Hubble's imaging spectrograph enabled the researchers to distinguish between features created by charged particles from Jupiter's magnetic bubble and plumes from Europa's surface, and also to rule out more exotic explanations such as serendipitously observing a rare meteorite impact.

The imaging spectrograph detected faint ultraviolet light from an aurora, powered by Jupiter's intense magnetic field, near the moon's south pole. Excited atomic oxygen and hydrogen produce a variable auroral glow and leave a telltale sign that are the products of water molecules being broken apart by electrons along magnetic field lines.

"We pushed Hubble to its limits to see this very faint emission. These could be stealth plumes, because they might be tenuous and difficult to observe in the visible light," said Joachim Saur of the University of Cologne, Germany. Saur, who is principal investigator of the Hubble observation campaign, co-wrote the paper with Roth.

Roth suggested that long cracks on Europa's surface, known as lineae, might be venting water vapor into space. Cassini has seen similar fissures that host the Enceladus jets.

Also the Hubble team found that the intensity of the Europa plumes, like those at Enceladus, varies with Europa's orbital position. Active jets have only been seen when the moon is farthest from Jupiter. The researchers could not detect any sign of venting when Europa is closer to Jupiter.

One explanation for the variability is that these lineae experience more stress as gravitational tidal forces push and pull on the moon and open vents at larger distances from Jupiter. The vents are narrowed or closed when the moon is closest to the gas-giant planet.

"The apparent plume variability supports a key prediction that Europa should tidally flex by a significant amount if it has a subsurface ocean," said Kurt Retherford, also of Southwest Research Institute.

The Europa and Enceladus plumes have remarkably similar abundances of water vapor. Because Europa has a roughly 12 times stronger gravitational pull than Enceladus, the minus-40-degree-Fahrenheit (minus-40-degree-Celsius) vapor for the most part doesn't escape into space as it does at Enceladus, but rather falls back onto the surface after reaching an altitude of 125 miles (201 kilometers), according to the Hubble measurements. This could leave bright surface features near the moon's south polar region, the researchers hypothesize.

"If confirmed, this new observation once again shows the power of the Hubble Space Telescope to explore and opens a new chapter in our search for potentially habitable environments in our solar system," said John Grunsfeld, an astronaut who participated Hubble servicing missions and now serves as NASA's associate administrator for science in Washington. "The effort and risk we took to upgrade and repair Hubble becomes all the more worthwhile when we learn about exciting discoveries like this one from Europa."

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

To view the images of the evidence for plumes visit: http://www.nasa.gov/content/goddard/hubble-europa-water-vapor.

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First step of metastasis halted in mice with breast cancer

Dec. 12, 2013 — Cell biologists at Johns Hopkins have identified a unique class of breast cancer cells that lead the process of invasion into surrounding tissues. Because invasion is the first step in the deadly process of cancer metastasis, the researchers say they may have found a weak link in cancer's armor and a possible new target for therapy. A summary of their results will be published online in the journal Cell on Dec. 12.

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"Metastasis is what most threatens breast cancer patients, and we have found a way to stop the first part of the process in mice," says Andrew Ewald, Ph.D., assistant professor of cell biology at the Johns Hopkins School of Medicine.

Before metastasis occurs, single cells on the edge of a tumor, termed leader cells, form protrusions into the surrounding tissue, like someone dipping a toe in to test the water before deciding to venture farther, Ewald says. If the conditions are right, the leader cells act as guides, with many tumor cells following behind, as they escape the confines of the tumor into the healthy tissue beyond. Full metastasis occurs when the cells succeed in migrating to a new location -- the lungs, for example -- and set up shop, creating a new tumor.

Beginning with the idea that some cells in the tumor might be more invasive than others, Ewald's team grew mouse tumors in the laboratory in special 3-D gels that mimic the environment that surrounds breast tumors in human patients. Kevin Cheung, M.D., a medical oncology fellow in the Ewald lab, observed that the cancer cells infiltrated the gels in groups, with a few cells out in front and the rest following behind.

Looking for a molecular cause for the apparent "leadership" seen in the initiating cells, Cheung searched for proteins that were uniquely present in the leader cells. They identified one protein, cytokeratin 14, or K14, that was present in almost all leader cells but was very rare in the noninvasive parts of the tumor. When the team looked at tumors from mice that had other types of breast cancer -- some more prone to invasion and others less prone -- all had leader cells containing K14. The more invasive a tumor was, the more cells with K14 it had.

The team then grew breast tumors from 10 breast cancer patients in 3-D gels and found that the leader cells in these human tumors also contained K14. "Our research shows that the most invasive cells in breast tumors express K14 across all types of breast cancer," says Cheung. "Now we need to learn how to eliminate these leader cells from breast tumors in patients."

K14 is a protein that helps form the internal "skeleton" of many cell types, giving them structure and helping them to move. Although its presence in leader cells made its involvement in the invasion process seem likely, the investigators conducted further experiments to determine whether it was essential to the process or merely coincidental to it.

The researchers removed breast tumors from mice with breast cancer and divided them into an experimental group and a control group. Each group of tumors was exposed to viruses that had been reprogrammed to carry pieces of genetic material into the cells. The experimental group received genetic material designed to prevent the production of K14; the control group got genetic material that didn't affect the cells. The two groups of tumors were then transplanted into healthy mice, with experimental tumors on one side and control tumors on the other side of the same mouse.

After letting the tumors grow for some time, the team removed and examined them. As expected, in the control group, leader cells were present, contained K14 and were leading vigorous invasions into normal tissue. In the experimental tumors, whose cells had no K14, the tumor borders were smooth, with essentially no invasions occurring.

"We're still several years away from being able to use these insights to help patients with breast cancer, but we now know which tumor cells are the most dangerous, and we know some of the proteins they rely on to do their dirty work," says Ewald. "Just a few leader cells are sufficient to start the process of metastasis, and they require K14 to lead the invasion."

He also notes that K14 is present in cells within many other organs, so K14 may play a similar role in other types of cancer.

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Fast radio bursts might come from nearby stars

"We propose that fast radio bursts aren't as exotic as astronomers first thought," says lead author Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA).

Fast radio bursts are both brief and bright, packing a lot of energy into a short time. Only six have been discovered to date, all of them in archival data. Each was detected only once, making follow-up studies difficult.

A detailed analysis of the bursts showed that the pulses passed through a large column of electrons on their way to Earth. If those electrons were spread out across intergalactic space, then the pulses must have crossed billions of light-years. As a result, they would have to come from extremely energetic events. Gamma-ray bursts don't produce the right radio frequencies, so astronomers looked to other extreme events like the collapse of a neutron star into a black hole.

Loeb and his colleagues reasoned that if the bursts came from a closer location, within the Milky Way galaxy, then they wouldn't require as much energy. The explanation could be more mundane.

Stellar flares fit the bill. Tightly packed electrons in the stellar corona would cause the same effect as the more diffuse intergalactic electrons.

Two types of stars are known to create radio bursts: young, low mass stars and solar-mass "contact" binaries which orbit so close that they share their outer, gaseous envelopes. Both types of star system would also fluctuate in brightness at optical wavelengths (i.e. visible light).

To test their theory Loeb and his colleagues searched the locations of three fast radio bursts to look for variable stars, using the telescopes at Tel-Aviv University's Wise Observatory, in Israel.

"It was straightforward to monitor these fields for several nights, to see if they showed anything unusual," says Dani Maoz of Tel Aviv University.

"We were surprised that, apparently, no one had done this before," adds Yossi Shvartzvald, a graduate student who led the observations.

They discovered a contact binary system in one location. The binary consists of two Sun-like stars orbiting each other every 7.8 hours. They are located about 2,600 light-years from Earth. Statistics of stars across the observed field of view show that there is less than a 5 percent chance that the binary star is in the right place by coincidence.

"Whenever we find a new class of sources, we debate whether they are close or far away," says Loeb. Gamma-ray bursts were initially thought to be coming from within the Milky Way; only later did astronomers learn they came from cosmological distances.

"Here we have exactly the opposite," explains Loeb. Fast radio bursts, initially thought to be distant, may actually originate from our own galaxy.

The study has been accepted for publication in the Monthly Notices of the Royal Astronomical Society.

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Surprise: Duck-billed dinosaurs had fleshy 'cocks comb'

Dec. 12, 2013 — A rare, mummified specimen of the duck-billed dinosaur Edmontosauraus regalis described in the Cell Press journal Current Biology on December 12 shows for the first time that those dinosaurs' heads were adorned with a fleshy comb, most similar to the roosters' red crest.

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The most common dinosaurs in North America between 75 and 65 million years ago, duck-billed dinosaurs were gentle giants, about 12 meters long, and filled the same ecological role that kangaroos or deer play today. But no one had suspected that they -- or other dinosaurs, for that matter -- had fleshy structures on the tops of their heads.

"Until now, there has been no evidence for bizarre soft-tissue display structures among dinosaurs; these findings dramatically alter our perception of the appearance and behavior of this well-known dinosaur and allow us to comment on the evolution of head crests in this group," says Phil Bell from Australia's University of New England. "It also raises the thought-provoking possibility of similar crests among other dinosaurs."

The dinosaur specimen in question was found in deposits west of the city of Grande Prairie in west-central Alberta, Canada. Bell, along with Federico Fanti from the University of Bologna, Italy, knew they had something special when they found skin impressions on parts of the mummified body. But it wasn't until Bell put a chisel through the top of the crest that he realized they really had something incredible.

"An elephant's trunk or a rooster's crest might never fossilize because there's no bone in them," Bell explains. "This is equivalent to discovering for the first time that elephants had trunks. We have lots of skulls of Edmontosaurus, but there are no clues on them that suggest they might have had a big fleshy crest. There's no reason that other strange fleshy structures couldn't have been present on a whole range of other dinosaurs, including T. rex or Triceratops."

Of course, it's hard to tell what that cocks comb might have done for the duck-billed dinosaurs. In roosters and some other birds, bright red crests are a way to get the girls. "We might imagine a pair of male Edmontosaurus sizing each other up, bellowing, and showing off their head gear to see who was the dominant male and who is in charge of the herd," Bell says.

We may never know exactly, but the new study is a useful reminder of just how bizarre and amazing dinosaurs really were, the researchers say. There is much left to discover.

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