Jul 13, 2013

Disks Don't Need Planets to Make Patterns, NASA Study Shows

Many young stars known to host planets also possess disks containing dust and icy grains, particles produced by collisions among asteroids and comets also orbiting the star. These debris disks often show sharply defined rings or spiral patterns, features that could signal the presence of orbiting planets. Astronomers study the disk features as a way to better understand the physical properties of known planets and possibly uncover new ones.

But a new study by NASA scientists sounds a cautionary note in interpreting rings and spiral arms as signposts for new planets. Thanks to interactions between gas and dust, a debris disk may, under the right conditions, produce narrow rings on its own, no planets needed.

Watch the changing dust density and the growth of structure in this simulated debris disk, which extends about 100 times farther from its star than Earth's orbit around the sun. At left, the disk is seen from a 24-degree angle; at right, it's face-on. Lighter colors show higher dust density.

"When the mass of gas is roughly equal to the mass of dust, the two interact in a way that leads to clumping in the dust and the formation of patterns," said lead researcher Wladimir Lyra, a Sagan Fellow at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "In essence, the gas shepherds the dust into the kinds of structures we would expect to be see if a planet were present."

A paper describing the findings was published in the July 11 issue of Nature.

The warm dust in debris disks is easy to detect at infrared wavelengths, but estimating the gas content of disks is a much greater challenge. As a result, theoretical studies tend to focus on the role of dust and ice particles, paying relatively little attention to the gas component. Yet icy grains evaporate and collisions produce both gas and dust, so at some level all debris disks must contain some amount of gas.

"All we need to produce narrow rings and other structures in our models of debris disks is a bit of gas, too little for us to detect today in most actual systems," said co-author Marc Kuchner, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Md.

Here's how it works. When high-energy ultraviolet light from the central star strikes a clump of dust and ice grains, it drives electrons off the particles. These high-speed electrons then collide with and heat nearby gas.

The rising gas pressure changes the drag force on the orbiting dust, causing the clump to grow and better heat the gas. This interaction, which the astronomers refer to as the photoelectric instability, continues to cascade. Clumps grow into arcs, rings, and oval features in tens of thousands of years, a relatively short time compared to other forces at work in a young solar system.

A model developed by Lyra and Kuchner shows the process at work.

"We were fascinated to watch this structure form in the simulations," Lyra said. "Some of the rings begin to oscillate, and at any moment they have the offset appearance of dust rings we see around many stars, such as Fomalhaut."

In addition, dense clumps with many times the dust density elsewhere in the disk also form during the simulation. When a clump in a ring grows too dense, the ring breaks into arcs and the arcs gradually shrink until only a single compact clump remains. In actual debris disks, some of these dense clumps could reflect enough light to be directly observable.

"We would detect these clumps as bright moving sources of light, which is just what we're looking for when we search for planets," adds Kuchner.

Read more at Science Daily

Boston Strangler Case: How Long Does DNA Last?

The news that 50-year-old DNA provided a break in the Boston Strangler murder case may have you wondering: just how long does DNA last?

Yesterday, investigators on the Boston Strangler murders, which occurred in the 1960s, said that DNA taken from a blanket at one crime scene was a very close match to that of a family member of Albert DeSalvo, the suspected killer.

The findings thus link DeSalvo to the crime scene. Officials now have permission to exhume the remains of DeSalvo, who died in 1973, to test DNA from his body and confirm the match, according to the New York Times.

DNA degrades over time, and just how long it lasts depends on how well it's preserved. Factors such as exposure to heat, water and sunlight can cause the molecule to degrade faster, according to Slate. The best way to preserve DNA is by freezing it, and sealing it in vacuum-packed container, Slate says.

Last year, researchers estimated that the half-life of DNA — the point at which half the bonds in a DNA molecule backbone would be broken — is 521 years. That means that, under ideal conditions, DNA would last about 6.8 million years, after which all the bonds would be broken. But DNA would not be readable after about 1.5 million years, the researchers said.

The oldest DNA recorded was found in Greenland ice, and estimated to be between 450,000 and 800,000 years old.

From Discovery News

Jul 12, 2013

The Toll of Growing Up in a Religious Cult

Children who grow up in religious cults face diffiulties not only during their childhood, but also after leaving the group.

That is the conclusion of research being presented today, Friday 12 July 2013, by the Chartered Psychologist Jill Mytton at the Annual Conference of the Society's Division of Counselling Psychology in Cardiff.

In her research Jill Mytton worked with 262 adults (95 women and 167 men) who had lived in a religious group as children. Around 70 per cent of the sample lost their family on leaving, 27 per cent reported child sexual abuse and 68 per cent had found the experience of leaving traumatic.

She asked them to complete a battery of psychological measures. The results showed that the average scores of the 264 partiticpants on these measures were significantly higher than the general population.

Two other measurss -- the Group Psychological Abuse Scale and the Extent of Group Identity Scale -- were used to assess the group environment and the level of group involvement respectively, and significant correlations were found between them and all clinical measures. This may mean that the specifics of the group environment, coupled with how strongly the group identity is enmeshed with personal identity, are key factors in the causation of distress in this sample.

Jill Mytton says: "Second-generation adult survivors of high-demand groups face particular difficulties, not only during their childhood, but also upon leaving the group, because they face assimilation into a culture that is not just alien to them but also one that they have been taught is wicked and to be hated."

From Science Daily

Why Do Cats Go Nuts for Lasers?

Every morning my cat paws at the hand mirror on the dresser until I use it to bounce a beam of morning sunlight around the room for her to chase. The internet hosts an abundance of videos of cats and dogs going nuts for laser pointer beams. Why do pets obsess over light beams?

Animal behaviorists believe the dots’ rapid, random movement trigger the animals’ predatory instincts and spurs them into an ultimately fruitless chase. Although it may seem obvious to humans that big differences exist between a laser dot and a mouse, people shouldn’t feel so superior. The most advanced ape on the planet falls for the same trick.

In an experiment, psychologists instructed people to watch the movement of dots of light on a screen and report when one of them disappeared. Most of the dots moved by simply bouncing around like in the old video game Pong. However some of the dots moved randomly, as if they were alive. People noticed when those “living” dots disappeared sooner than the Pong dots.

Considering how much time many people spend fixated on dots of light moving in life-like patterns, i.e. television, these results don’t surprise me.

For pets, the ultimately frustrating chase of laser dots can be psychologically harmful.

“They can get so wound up and driven with prey drive that once they start chasing the light they can’t stop. It becomes a behavior problem,” Nicholas Dodman, professor of animal behavior at Tufts University told Live Science. “I’ve seen light chasing as a pathology where they will just constantly chase around a light or shadow and pounce upon it. They just spend their whole lives wishing and waiting.”

Read more at Discovery News

Drifting Iceberg Spins Out Ocean Tunes

This is the sound of a splitting iceberg.

Like ice cubes cracking in a glass of warm soda, except louder.

Disintegrating icebergs generate significant noise pollution at the world’s poles, affecting narwhals, whales and other aquatic life, according to a study published June 18 in Oceanography. And with temperatures rising at the poles due to climate change, the oceans will only get louder.

The splitting of an iceberg over 20 minutes in the Antarctic’s Southern Ocean produces enough sound energy to equal that of 214 supertankers, according to the study.

“Sound from ice breakup in the Southern Ocean can be significantly greater than anthropogenic noise sources and thus are a major contributor to the overall ocean noise budget,” the authors state.

It had been assumed so far by oceanographers that the loudest noises in the oceans of the Arctic and Antarctic are generated by direct human activity, such as the sonic booms emitted by vessels exploring for oil, by shipping traffic, and sonar.

Scientists have previously listened in on icebergs running aground and scraping against the sea floor. But this is the first time that an iceberg’s final moments before disintegration have been documented in sound.

Between April and June 2007, the A53a iceberg was drifting in the Weddell Sea of Antarctica when it hit a shoal. Robert Dziak of Oregon State University and his colleagues had installed an array of hydropones in the area, and they were able to listen in to the sharp bursts of sound called harmonic tremors the iceberg made as it spinned.

By July, the iceberg got free of the shoal, and floated north into the warmer Scotia Sea where it started melting. Melt ponds appeared on the surface, a sure sign it was disintegrating. By September, it was no more. Researchers were most interested in these final moments of A53a.

They recovered the data from the hydropone array and listened to the sounds, called icequakes. It was entirely different from harmonic tremors of an iceberg running aground.

Since sound is a form of energy, Dziak was able to calculate the energy flows through the ocean over a 20 minute period, which equaled the sound energy generated by 214 ships.

A number of aquatic mammals are affected by noise pollution. At the poles especially, the oceans are usually so quiet that the animals are not habituated to anthropogenic noise.

Read more at Discovery News

The Explosive, Beautiful Death of a Star

Although they may shine for many billions of years, stars like our sun don't last forever and when it's time for them to fizzle away into the night they most certainly don't go gently -- but the result can be quite beautiful.

The image above, a composite of optical data from Hubble and x-ray observations from NASA's Chandra observatory, shows the brilliant structure of planetary nebula NGC 2392 -- a.k.a. the "Eskimo nebula."

Named for their supposed resemblance to planetary disks in early telescopes, planetary nebulae are created when stars up to about 8 times the mass of our sun run out of fuel during the final stages of their natural lives. Powerful gravitational convulsions within a failing star blast its outermost layers into space, and when the outwardly-expanding shells of material are then impacted by the star’s radiation they become ionized, causing them to glow.

The comet-shaped structures surrounding NGC 2392 are created by faster wind and radiation from the central star interacting with cooler shells of dust and gas that have already been ejected.

While not achieving the dramatic level of true supernova remnants, planetary nebulae like NGC 2392 are nonetheless fascinating targets for observation, not only for their unique beauty but also for the insight they can provide as to the eventual end of our own home star, the sun.

From Discovery News

Jul 11, 2013

Solar Tsunami Rips Across the Sun

Two solar observatories have joined forces to witness a rare phenomenon: a solar tsunami.

Immediately after an eruption of a coronal mass ejection in the lower corona (the sun’s multimillion degree atmosphere), observations by NASA’s Solar Dynamics Observatory (SDO) and Japan’s Hinode solar observatory tracked a vast wave blast across the upper plasma layers of the sun. By doing so, scientists were able to accurately measure the strength of the sun’s magnetic field and test a method that may ultimately help space weather forecasters predict the characteristics of coronal mass ejections (CMEs).

This particular tsunami — technically known as an “EIT wave” after the EIT instrument on board the veteran NASA/ESA Solar and Heliospheric Observatory (SoHO) that made their discovery — was clocked speeding at up to 1,000 kilometers (620 miles) per second through the highly magnetized, searingly hot solar plasma.

EIT waves are of huge importance to solar physics. Understanding the nature of the lower corona and the interface between the sun’s atmosphere and interior can be difficult; analysis of this extreme environment is limited by the hot plasma and complex magnetic fields bubbling through the solar surface. You can’t simply send a probe into the lower corona, it would be incinerated. So scientists depend on remote observations by an armada of space observatories to spot rare phenomena such as tsunamis to help gauge the lower coronal environment.

“These EIT waves are quite tricky — they’re very random and they’re relatively rare,” David Long, of University College London (UCL) Mullard Space Science Laboratory and lead investigator of the research, told BBC News. “We need to be in the right place at the right time; this has been a long time coming.” The study has been accepted for publication in the journal Solar Physics.

The SDO was used to keep track of the extreme ultraviolet emissions from the million-degree plasma the wave was propagating through and the EIS instrument on board Hinode tracked the density of the plasma. As the speed and shape of EIT waves is strongly affected by the sun’s magnetic field, these accurate measurements were used to deduce the magnetic environment the wave was traveling through.

“We’ve demonstrated that the sun’s atmosphere has a magnetic field about ten times weaker than a normal fridge magnet,” said Long in a UCL press release. Weaker it may be, but the sun’s magnetic field is extensive, dominating the entire solar system.

These measurements have practical implications for Earth, too.

As we become more and more dependent on technology in our daily lives, civilization is becoming increasingly vulnerable to the sun’s ‘temper tantrums.’ Every 11 years or so, the sun winds up into a highly stressed state; a period known as “solar maximum.” During these periods of intense solar activity (as the sun is now), we can expect an amplification in solar wind ferocity and an increase in frequency of solar flares and CMEs — all of which can interfere with communications and damage satellites, for example.

CMEs are of special concern, as when the huge magnetized bubbles of highly charged particles interact with our planet’s magnetic field they can generate huge currents through the atmosphere, threatening entire power grids. Therefore, accurate prediction and characterization of incoming CMEs is paramount.

Read more at Discovery News

Hot Spots Hit Earth's Hottest Place

You may have heard that on June 30th the official temperature at the headquarters of Death Valley National Park, Furnace Creek, was 129.2 Fahrenheit, making it the hottest June temperature measured on Earth in history. But that was hardly the hottest temperature in Death Valley that day, as the above U.S. Geological Survey (USGS) images reveal and my past experience as a ranger there tells me.

The false color image shows the ground temperatures on that very hot day. It was taken by the Thermal Infrared Sensor on the USGS’s Landsat 8 satellite. The lighter the color, the hotter the ground was in this image. The natural color view is in infrared and collected by the same satellite on the same day by the Operational Land Imager. One of the things that the images show is that, generally speaking, the higher you go, the cooler it was that day, which makes sense. Or does it?

Turns out it’s not as simple as elevation. The type of ground also matters and there are some very exotic kinds of ground in Death Valley. For instance, notice the area to the southwest (lower left) of Furnace Creek — the natural color image shows very bright ground that is actually cooler (darker) in the thermal image. That is because this area is lower than Furnace Creek and has no plants. Furnace Creek is darker in both images because of its trees and other plants. The cooler ground is made of highly reflective salt: miles and miles of salt crystals at the bottom of what was, tens of thousands of years ago, a vast inland sea with no outlet.

Now look at the dark brown (in natural light) alluvial fans coming out of the mountains on either side of the salt. They are much hotter (brighter in the thermal image), while being higher in elevation. These areas are made of a collection of darker rocks that have eroded from the mountains. The darker rocks absorb more sunlight, getting a lot hotter.

While surface temperatures are certainly different from air temperatures, the heat coming from the ground does play a big role in heating up the air a few feet off the ground where the official thermometers are typically kept. And if there are trees nearby shading the ground, as there are near the Furnace Creek thermometer station, that cools things as well.

Read more at Discovery News

Neanderthals Talked -- Like Us

Neanderthals, like modern humans, likely communicated among themselves and with others using tonal languages.

New research, published in the journal Frontiers in Language Sciences, presents strong evidence -- genetic, fossil, archaeological and more -- that modern speech and language existed among Neanderthals, Denisovans (a Paleolithic type of human), and early members of our own species.

“Modern humans and Neanderthals and Denisovans are very similar genetically, and there are indications of interbreeding as well, strengthening this similarity,” lead author Dan Dediu told Discovery News, explaining that a gene involved in language and speech, FOXP2, is present in all three groups.

Neanderthal genes also suggest that the stocky, yet brainy, individuals possessed tonal languages, since there is an association between tone and two of their genes involved in brain growth and development.

Dediu is a senior investigator in the Language and Genetics Department and is group leader of Genetic Biases in Speech and Language at the Max Planck Institute for Psycholinguistics.

In addition to outlining the DNA evidence, Dediu and colleague Stephen Levinson also explain that Neanderthals possessed a human-like hyoid bone, which is involved in speech production. Neanderthal ear bones further appear to have evolved for hearing speech in addition to other sounds, just as ours have.

Symbolism ties to language, since sounds and words represent specific concepts, and it appears that Neanderthals were big on both symbolism and culture.

“Recent discoveries and reinterpretation of the Neanderthal archaeological record support its capacity for symbolic culture (including their) complex toolkit, complex social life and its capacity to persist in the harsh and fluctuating western Eurasian climate of the time,” Dediu said.

The researchers believe modern speech and language first emerged in Homo heidelbergensis, an extinct species of the genus Homo that lived in Africa, Europe and western Asia from at least 600,000 years ago and possibly much earlier than that. This species might have been the common ancestor of Homo sapiens and Neanderthals.

Dediu and Levinson's work counters the theory that a single, or very few, genetic change(s) resulted in the acquisition of the capacity for language. Instead, the scientists hold that genes associated with language and culture co-evolved.

"The basic idea," Dediu explained, "is that cultural change is not simply an effect of a better genetic background; culture does not have to wait for biology change, but culture generates new selective pressures to which our biology must adapt, changes in biology that might allow new cultural changes in a co-evolutionary cycle."

The evolution of lactose tolerance and changes to our immune and digestive systems due to farming are all examples.

As for when an individual of any species first communicated in a complex way via sound, it’s possible the sound was a whistle, Mark Sicoli, an assistant professor in Georgetown University’s Department of Linguistics, told Discovery News. Sicoli studies whistled speech still used in parts of Oaxaca, Mexico.

"Hypothetically, whistled speech could be as old as the earliest languages," Sicoli said, adding that it could even have been a component of proto-language, the precursor of human language used by the earlier hominid species.

Read more at Discovery News

Hubble Spies a Blue Planet (Not Earth)

As far as planets go, HD 189733b, a giant, sizzling Jupiter-like world that swoops around its parent star every 2.2 days, couldn’t be more different from Earth.

But the planet, located 63 light-years away in the constellation Vulpecula (the Fox), has one feature that is familiar: it’s blue.

Astronomers weren’t specifically thinking about HD 189733b’s color per se when they requested observation time on the Hubble Space Telescope. They were following up previous studies showing the planet had clouds with an attempt to learn more about what is in its atmosphere.

As HD 189733b paraded around its star, astronomers used Hubble’s light-splitting spectrograph to home in on specific wavelengths of light reflecting off the planet’s surface.

HD 189733b is a so-called “transiting planet” meaning it passes in front of and then behind its host star, relative to the telescope’s line of sight. Taking data before, during and after eclipses often yields scientific treasures -- and in this case an aesthetic one as well.

When HD 189733b slipped behind the star, the light seen by Hubble dropped deeply into the blue part of the electromagnetic spectrum, while all other colors remained the same, a telltale sign of the planet's color.

HD 189733b is far too hot for liquid water, but there are other molecules that could scatter blue light, mirroring what happens in Earth’s atmosphere. Scientists believe HD 189733b has clouds made of liquid glass.

“Our best guess is that the color is due to a combination of reflection by silicate clouds and absorption by sodium atoms,” astronomer Frederic Pont, with the University of Exeter in the United Kingdom, wrote in an email to Discovery News.

“Other factors may be photochemical aerosols -- i.e. smog -- and absorption by other atoms or molecules than sodium,” though presently are no specific candidates,” he added.

Driving the planet’s extreme environment is its unenviable position 30 times closer to its parent star than Earth orbits the sun. At that distance, surface temperatures reach more than 1,800 degrees Fahrenheit.

To boot, the planet is likely gravitationally locked with one side permanently facing its star and the other in darkness. That dichotomy can generate wild winds that surpass 4,350 mph.

“I think of this planet in some ways as being about as alien a planet as you could possibly imagine,” astronomer Heather Knutson, with the California Institute of Technology (Caltech) in Pasadena, told Discovery News.

Read more at Discovery News

Jul 10, 2013

Researchers Create Inner Ear from Stem Cells, Opening Potential for New Treatments

Indiana University scientists have transformed mouse embryonic stem cells into key structures of the inner ear. The discovery provides new insights into the sensory organ's developmental process and sets the stage for laboratory models of disease, drug discovery and potential treatments for hearing loss and balance disorders.

A research team led by Eri Hashino, Ph.D., Ruth C. Holton Professor of Otolaryngology at Indiana University School of Medicine, reported that by using a three-dimensional cell culture method, they were able to coax stem cells to develop into inner-ear sensory epithelia -- containing hair cells, supporting cells and neurons -- that detect sound, head movements and gravity. The research was reportedly online Wednesday in the journal Nature.

Previous attempts to "grow" inner-ear hair cells in standard cell culture systems have worked poorly in part because necessary cues to develop hair bundles -- a hallmark of sensory hair cells and a structure critically important for detecting auditory or vestibular signals -- are lacking in the flat cell-culture dish. But, Dr. Hashino said, the team determined that the cells needed to be suspended as aggregates in a specialized culture medium, which provided an environment more like that found in the body during early development.

The team mimicked the early development process with a precisely timed use of several small molecules that prompted the stem cells to differentiate, from one stage to the next, into precursors of the inner ear. But the three-dimensional suspension also provided important mechanical cues, such as the tension from the pull of cells on each other, said Karl R. Koehler, B.A., the paper's first author and a graduate student in the medical neuroscience graduate program at the IU School of Medicine.

"The three-dimensional culture allows the cells to self-organize into complex tissues using mechanical cues that are found during embryonic development," Koehler said.

"We were surprised to see that once stem cells are guided to become inner-ear precursors and placed in 3-D culture, these cells behave as if they knew not only how to become different cell types in the inner ear, but also how to self-organize into a pattern remarkably similar to the native inner ear," Dr. Hashino said. "Our initial goal was to make inner-ear precursors in culture, but when we did testing we found thousands of hair cells in a culture dish."

Electrophysiology testing further proved that those hair cells generated from stem cells were functional, and were the type that sense gravity and motion. Moreover, neurons like those that normally link the inner-ear cells to the brain had also developed in the cell culture and were connected to the hair cells.

Additional research is needed to determine how inner-ear cells involved in auditory sensing might be developed, as well as how these processes can be applied to develop human inner-ear cells, the researchers said.

Read more at Science Daily

Supercooled Water Transforms Into New Form of Liquid

Researchers at the University of Arkansas have identified that water, when chilled to a very low temperature, transforms into a new form of liquid.

Through a simulation performed in “supercooled” water, a research team led by chemist Feng “Seymour” Wang, confirmed a “liquid-liquid” phase transition at 207 Kelvins, or 87 degrees below zero on the Fahrenheit scale.

The properties of supercooled water are important for understanding basic processes during cryoprotection, which is the preservation of tissue or cells by liquid nitrogen so they can be thawed without damaged, said Wang, an associate professor in the department of chemistry and biochemistry in the J. William Fulbright College of Arts and Sciences.

“On a miscrosecond time scale, the water did not actually form ice but it transformed into a new form of liquid,” Wang said. “The study provides strong supporting evidence of the liquid-liquid phase transition and predicted a temperature of minimum density if water can be cooled well below its normal freezing temperature. Our study shows water will expand at a very low temperature even without forming ice.”

The findings were published online July 8 in the journal Proceedings of the National Academy of Sciences. Wang wrote the article, “Liquid–liquid transition in supercooled water suggested by microsecond simulations.” Research associates Yaping Li and Jicun Li assisted with the study.

The liquid–liquid phase transition in supercooled water has been used to explain many anomalous behaviors of water. Direct experimental veri?cation of such a phase transition had not been accomplished, and theoretical studies from different simulations contradicted each other, Wang said.

The University of Arkansas research team investigated the liquid–liquid phase transition using a simulation model called Water potential from Adaptive Force Matching for Ice and Liquid (WAIL). While normal water is a high-density liquid, the low-density liquid emerged at lower temperatures, according to the simulation.

The research was supported by a National Science Foundation Faculty Early Career Development Award and by a startup grant from the U of A. The University of Arkansas High Performance Computing Center provided the main computational resource for the study.

From Science Daily

Green Crabs Devouring America's Seafood

Green crabs may devour America’s entire seafood buffet. In New England, the crabs (Carcinus maenas) started by pinching scallop and mussel populations. Now the crabs chomp on clams. Fisheries managers fear that the crabs will move onto the king of American seafood, the Maine lobster (Homarus americanus).

“[The crabs’] food preference has systematically moved through all of shellfish resources on a sequence based on convenience,” Chad Coffin, president of Maine Clammers Association, told the Bangor Daily News. “When the clams are gone, what are they going to eat? People may think lobsters are big and tough, but they’re not.”

On the other side of the continent, invading hordes of green crabs devour oysters and other crab species, including the delicious Dungeness, in the waters off Oregon and Washington.

Green crabs lack the claw strength to crack into full-grown oysters and other marine mollusks. Instead, the crabs dig young oysters and clams out of up to six inches of sand. The invaders can consume 40 half-inch clams per day, according to the Washington Department of Fish and Wildlife.

Cold waters used to keep lobsters and other marine life relatively safe from the green crab invasion. The crabs are native to the coastal waters of Europe warmed by currents flowing north from the tropics. Chilly winter waters on the East Coast of North America used to knock out invasive green crab populations periodically.

However, as the ocean’s temperature increases the green crab killing chills occur less frequently and the invaders’ numbers are skyrocketing.

Unfortunately, the booming green crab population won’t make for discount crab legs. Although they are edible, the green crab has little meat and getting at that meat takes a frustrating amount of effort, according to the Sustainable Ecosystems Institute. Research at the University of Maine studied the feasibility of mechanically processing the crabs and making breaded cakes from them.

Read more at Discovery News

Dogs With American Roots Revealed

Alaskan breeds -- such as Inuit sled dogs, the Eskimo dog and the Greenland dog -- are the only canines with actual American roots, according to DNA analysis. All of these pooches hail from the 49th state and nearby areas, according to the study, published in the latest Proceedings of the Royal Society B.

“They are all equally American,” co-author Peter Savolainen told Discovery News. “They originate from the indigenous Indian-American and Inuit dog populations, and have only marginally been mixed with European dogs in modern time.”

Savolainen, an associate professor at KTH-Royal Institute of Technology in Sweden, explained the determination after tracing the origin of mitochondrial DNA lineages for several dog breeds suspected to be pre-Columbian, meaning before Europeans settled in the Americas. Dogs inherit their mitochondrial DNA from their mothers.

Scientists widely agree that the original stock of all canines worldwide originated from Asia. This is similar to the widely agreed-upon view that all members of our species originated in Africa before some people left that continent.

“There was a single origin of the domestic dog somewhere in Eurasia,” Savolainen explained. “The exact place is still debated, but our previous studies strongly indicate the southern part of East Asia, basically southern China.”

The earliest archaeological evidence for dogs in the Americas dates to around 10,000 years ago, long before the dawn of transoceanic travel in the 15th century that saw the arrival of Columbus and other Europeans.

Most U.S. dogs today, however, have European origins. Golden retrievers, poodles and many more breeds fall into this category.

Inuit sled dogs, the Eskimo dog and the Greenland dog, though, show no European heritage in their genes. Like Native Americans, they were in the United States and nearby areas long before Europeans arrived.

“Nobody knows exactly what happened,” Savolainen said. “Most probably migrated together with the humans that entered America from Asia via the Bering Strait. These humans became today’s Indians and Inuits.”

“Our data shows dogs came in several migrations, at least one with the Indian-American ancestors and at least one with the Inuit ancestors,” he continued.

The result for Alaskan Malamutes was ambiguous, but these dogs appear to come from slightly different stock originating in Siberia, Japan, China and Indonesia. The Alaskan husky and the American Eskimo dog have a known origin from Siberian spitzes and European dogs.

The dogs with the most pre-Columbian Mexican heritage, according to the study, are the Chihuahua and Xolo (Mexican hairless dog).

The researchers additionally determined that a group of free-ranging dogs based in South Carolina and Georgia -- known as Carolina Dogs -- likely have an ancient Asian origin.

Carolina Dogs might have once been associated with a Native American tribe, the canine's relatives turning feral once their humans disappeared.

“The reason might be that the human population keeping these dogs was wiped out when Europeans came,” Savolainen said.

Prior research by Sarah Brown of UC Davis and colleagues is consistent with the latest findings about the Inuit sled dog, Eskimo dog and Greenland dog. Brown and her team found “ancient DNA evidence for genetic continuity in arctic dogs.”

Read more at Discovery News

Jul 9, 2013

Pharaoh's Sphinx Paws Found in Israel

Archaeologists digging in Israel say they have made an unexpected find: the feet of an Egyptian sphinx linked to a pyramid-building pharaoh.

The fragment of the statue's front legs was found in Hazor, a UNESCO World Heritage Site just north of the Sea of Galilee. Between the paws is a hieroglyphic inscription with the name of king Menkaure, sometimes called Mycerinus, who ruled Egypt during the Old Kingdom more than 4,000 years ago and built one of the great Giza pyramids.

Researchers don't believe Egypt had a relationship with Israel during Menkaure's reign. They think it's more likely that the sphinx was brought to Israel later on, during the second millennium B.C. (Images: Glitzy Discovery at Giza Pyramids)

The inscription also includes the phrase, "Beloved by the divine manifestation … that gave him eternal life." Amnon Ben-Tor, one of the Hebrew University archaeologists leading the excavations at Hazor, thinks that descriptor could be a clue the sphinx originated in the ancient seat of sun worship, Heliopolis, which is today mostly destroyed and covered up by Cairo's sprawl.

The part-lion, part-human sphinx was a mythical creature represented in art throughout the ancient Near East as well as India and Greece. Ben-Tor and colleagues say the artifact found at Hazor is the first-ever discovered sphinx fragment associated with king Menkaure. It's also the only royal Egyptian sphinx ever to be unearthed in Israel, according to a statement from Hebrew University.

The statue fragment was exposed at the entrance to the city palace in an archaeological layer that dates to the mysterious destruction of Hazor when it was occupied by the Canaanites in the 13th century B.C.

The researchers think the sphinx could have been brought to Israel during the 17th to 16th centuries B.C., when part of Egypt was controlled by the Hyksos, a people believed to be originally from northern Canaan. Alternatively, the royal sculpture may have arrived in Hazor as a gift from an Egyptian king during the 15th to 13th centuries B.C., when Egypt controlled much of Canaan through a system of vassal states. At that time, Hazor was the most important city in the southern Levant, covering some 200 acres (80 hectares), with an estimated population of about 20,000.

Read more at Discovery News

Ancient City of Angkor Bigger Than Thought

Angkor, the ancient capital of the Khmer Empire, has been mapped for the first time using laser light.

The technique called LIDAR, which uses billions of reflected light beams to map the topography below a thick forest canopy, revealed that the city was even more massive than previously thought.

The new analysis "shows there were hundreds, if not thousands of settlements, mounds, ponds, roads and urban blocks which actually organized a quite dense city," said study co-author Christophe Pottier, an archaeologist and co-director of the Greater Angkor Project. "This area of dense occupation was much bigger than what we were expecting."

The findings were published in the journal Proceedings of the National Academy of Sciences.

Ancient empire
Angkor is located in modern-day Cambodia, and for several centuries, was the capital city of the Khmer Empire. The city and its surrounding areas may have housed up to 1 million people and, at its height, was considered the largest city in the world. Angkor flourished until the 15th century, when it was mysteriously abandoned. The crown jewel of the complex, Angkor Wat, is a temple built between A.D. 1113 and 1150 that rises 213 feet (65 meters) into the air and spans 500 acres (200 hectares).

After the city was abandoned, the jungle took over, covering the area in a thick canopy of vegetation. In the past, researchers had tried to study its extent using radar and satellite images. But much of the ancient city's footprint remained hidden.

In 2012, Pottier and his colleagues began mapping the terrain using airborne laser scanning, or LIDAR. The team used a helicopter and sent out billions of beams of laser light that were able to pass through the tiny spaces between dense jungle canopy to hit the earth below. The reflected beams were then analyzed to determine whether the light bounced off leaves, soil or other features.

The LIDAR uncovered hundreds of bumps on the landscape that ancient inhabitants formed when moving earth to build dikes, dams, huge reservoirs, canals, family ponds and roads. The new map reveals that the city made heavy use of cultivation and water-storing techniques. (Scientists recently discovered a lost Khmer city known only from inscriptions using the same technology.)

In addition, the city's dense core was much larger than thought: about 27 square miles (70 square kilometers), Pottier said. The core alone may have housed 500,000 people, he added.

Read more at Discovery News

Ice Above Lake Vostok Includes DNA From Animals

Microbes that live inside fish intestines are among the array of life that appear to have been found in ice drilled from above Lake Vostok, the deepest lake buried beneath Antarctica's ice sheet.

The ice is thought to be from frozen Vostok lake water, chilled by contact with the lake's overlying glacier. Called accretion ice, scientists first reported evidence of microbes in this ice in the journal Science in 1999. In some spots above the lake, the accretion ice is more than 650 feet (200 meters) thick and 20,000 years old, scientists believe. Though ice has sealed the surface for up to 15 million years, subglacial waterways may have refreshed the lake and even brought in life from outside the basin, scientists think.

Now, a new study of genetic material in the accretion ice reveals more than 3,500 unique traces of life in Lake Vostok, including animals, from a wide variety of ecosystems. Most of the snippets of DNA and RNA are from bacteria and fungi, according to the report, published July 3 in the journal PLOS ONE. Some sequences match living microbes pulled from the same ice cores by the research team in 2008 and 2009, said senior author Scott Rogers, a molecular biologist at Bowling Green State University in Ohio.

Although the researchers found genetic evidence of many different organisms in the ice, the overall concentration was incredibly low compared with water from lake systems on other continents, Rogers said, ranging between one cell to 100 cells per milliliter (0.04 ounces) of fluid. "If [Lake Vostok] does have life, it's interesting life, but it's not highly concentrated life," Rogers told LiveScience.

A cross-section of Lake Vostok shows how ice accumulates above the lake, and a list of some of the different organisms discovered in the ice core.
New view of Vostok

Lake Vostok is Antarctica's biggest and deepest subglacial lake; its surface sits 1,600 feet (500 m) below sea level. It is roughly the size of Lake Ontario and lies beneath 2 miles (3.2 kilometers) of ice. The lake basin is about 35 million years old and was entombed after Antarctica underwent a deep freeze about 15 million years ago. Signs of subglacial waterways suggest rivers, streams or floods periodically refresh the lake, so the water in the lake is much younger than 15 million years. However, Rogers estimates the accretion ice tested in the study is between 5,000 to 10,000 years old.

The ice cores analyzed in the current study have been shared and scrutinized internationally since they were extracted in the 1990s by Russian scientists. The first hints of life turned up soon after the cores were removed, such as in the series of papers published in Science in 1999.

In their new study, Rogers and his colleagues discovered genetic sequences from cold-loving extremophiles, adapted to the chilly, light-poor environment. Among the bacteria were species that live in hydrothermal vents and organisms that colonize the intestines of rainbow trout, lobsters and tubeworms.

The team also found stretches of RNA and DNA from animals such as tiny, deep-sea-living mollusks and the water flea, a small floating crustacean found in almost every permanent water body on Earth. "The organisms we've been finding are in the very, very small range. These are tiny little creatures," Rogers said.

Finding Vostok's hotspot

Reports of life from Antarctic lakes, especially from the Vostok ice cores, have been plagued by problems with contamination. In the past decade, Rogers and his team developed a painstaking decontamination technique to remove genetic contagion on the outside of the ice core while preserving the ancient DNA and RNA within, he said. The method involves a bleach wash, as well as melting, filtering and refreezing the ice.

"Contamination is still a concern, but we think the contamination methods we have developed ensure that all the external contamination has been eliminated," Rogers said.

In the future, the team plans to conduct genetic tests on additional ice cores to pin down the center of biological activity above the lake. Studies suggest the shallow part of the lake is the active zone, with the highest cell counts in ice cores from above this region, Rogers said.

"As you get further out into the lake, the cell count really drops," he said. "We're interested in finding out what's there and how they're able to live there. Life seems to find a way to survive almost everywhere on Earth that you can go."

Read more at Discovery News

Event Horizon Telescope Will Snap a Black Hole

Black holes are essentially invisible, but astronomers are developing technology to image the immediate surroundings of these enigmas like never before. Within a few years, experts say, scientists may have the first-ever picture of the environment around a black hole, and could even spot the theorized "shadow" of a black hole itself.

Black holes are hard to see in detail because the large ones are all far away. The closest supermassive black hole is the one thought to inhabit the center of the Milky Way, called Sagittarius A* (pronounced "Sagittarius A-star"), which lies about 26,000 light-years away. This is the first target for an ambitious international project to image a black hole in greater detail than ever before, called the Event Horizon Telescope (EHT).

The EHT will combine observations from telescopes all over the world, including facilities in the United States, Mexico, Chile, France, Greenland and the South Pole, into one virtual image with a resolution equal to what would be achieved by a single telescope the size of the distance between the separated facilities.

"This is really an unprecedented, unique experiment," said EHT team member Jason Dexter, an astrophysical theorist at the University of California, Berkeley. "It's going to give us more direct information than we've ever had to understand what happens extremely close to black holes. It's very exciting, and this project is really going to come of age and start delivering amazing results in the next few years."

From Earth, Sagittarius A* looks about as big as a grapefruit would on the moon. When the Event Horizon Telescope is fully realized, it should be able to resolve details about the size of a golf ball on the moon. That's close enough to see the light emitted by gas as it spirals in toward its doom inside the black hole.

Very Long Baseline Interferometry

To accomplish such fine resolution, the project takes advantage of a technique called very long baseline interferometry (VLBI). In VLBI, a supercomputer acts as a giant telescope lens, in effect.

"If you have telescopes around the world you can make a virtual Earth-sized telescope," said Shep Doeleman, an astronomer at MIT's Haystack Observatory in Massachusetts who's leading the Event Horizon Telescope project. "In a typical telescope, light bounces off a precisely curved surface and all the light gets focused into a focal plane. The way VLBI works is, we have to freeze the light, capture it, record it perfectly faithfully on the recording system, then shift the data back to a central supercomputer, which compares the light from California and Hawaii and the other locations, and synthesizes it. The lens becomes a supercomputer here at MIT."

A major improvement to the Event Horizon Telescope's imaging ability will come when the 64 radio dishes of the ALMA (Atacama Large Millimeter/submillimeter Array) observatory in Chile join the project in the next few years.

"It's going to increase the sensitivity of the Event Horizon Telescope by a factor of 10," Doeleman said. "Whenever you change something by an order of magnitude, wonderful things happen."

Very long baseline interferometry has been used for about 50 years, but never before at such a high frequency, or short wavelength, of light. This short-wavelength light is what's needed to achieve the angular resolution required to measure and image black holes.

Grand Technical Challenge

Pulling off the Event Horizon Telescope has been a grand technical challenge on many fronts.

To coordinate the observations of so many telescopes spread out around the world, scientists have needed to harness specialized computing algorithms, not to mention powerful supercomputers. Plus, to accommodate the time difference between the various stations, extremely accurate clocks are needed.

"We had to prove you could keep time well enough at all the stations, and that the detectors at all the telescopes were good enough, that when you multiply the two signals from two telescopes you wouldn’t get just noise," said Dan Marrone, an astronomer at the University of Arizona's Steward Observatory who's building a receiver to enable the South Pole Telescope to join the project.

The researchers have been using atomic clocks made of what's called hydrogen masers to keep time to an accuracy of about a trillionth of a second per second.

"We use this property of the structure of the hydrogen atom to create a fundamental time reference for us that transitions between two states of the electron in a hydrogen atom," Marrone said. "It creates a low-frequency signal that through careful design you can make a very precise oscillator. It creates very perfect oscillations for a short time period. That means we can average our data over those time periods because they will all have kept time very perfectly."

Testing General Relativity

With the unprecedented data soon to be collected by the Event Horizon Telescope, scientists are hoping to better understand the strange physics of black holes, which are some of the most extreme, bizarre objects in the universe.

The black hole at the center of the Milky Way is thought to contain the mass of about 4 million suns, all packed into an incomprehensibly small area. The ultra-strong densities there should produce some very extreme gravitational forces that offer a rare test of Einstein's general theory of relativity.

"The Event Horizon Telescope is going to look at emission at the edge of the black hole itself," Doeleman said. "That's an area where the gravity is so strong that light is bent and the structures you see are dominated by strong gravity, where you absolutely need Einstein to understand what you're seeing. It becomes a laboratory of extremes."

One question scientists hope to answer is whether black holes really have event horizons, as predicted by general relativity. An event horizon is a theorized boundary around a black hole that marks the "point of no return" where matter and even light can't escape. If event horizons exist, general relativity also predicts black holes will have shadows, or darkened regions where light has been swallowed. If black holes do produce shadows, the Event Horizon Telescope should be able to see one at Sagittarius A* within the next few years, said Dexter, the University of California, Berkeley, theorist.

"That would be the most extreme general relativistic effect detected so far," he added.

X-raying Black Holes

While the Event Horizon Telescope is observing black holes in radio wavelengths, the other frontier of black hole astronomy is in the X-ray regime.

The gas falling into black holes emits light across the electromagnetic spectrum, but the hottest, most energetic gas, which is swirling closest to a black hole's event horizon, can be seen in X-ray light.

This light is only visible beyond the atmosphere of Earth, to space telescopes such as NASA's Chandra observatory and NuSTAR telescope, Europe's XMM Newton observatory, and Japan's Suzaku telescope. These observations aren't directly imaging the environs of black holes, like the Event Horizon Telescope, but are breaking up X-ray light into its constituent colors, or wavelengths, to search for clues about what's happening to the gas in those extreme environments.

For example, astronomer Chris Reynolds of the University of Maryland, College Park, uses X-ray observations to study the spins of black holes. "Because the physics is so extreme, when a black hole spins, it actually twists up the space-time around it and we can see the effect it has on gas orbiting the black hole," Reynolds said.

And by studying black holes in various wavelengths, researchers hope to build up a more complete understanding of these strange cosmic objects.

Read more at Discovery News

Jul 8, 2013

Archaeologists Unearth a Virtually Intact Late Roman Well

Archaeologists from the University of York say a virtually intact Late Roman well discovered near Heslington, on the outskirts of the city, may have had significance in contemporary local agricultural cycles and fertility practices.

The well, which is thought to have been in use for several decades in the late 4th and early 5th centuries, was unearthed during archaeological excavations on the site of the University's campus expansion at Heslington East.

From at least the Early Bronze Age, a range of methods were used here to access natural springs, including watering holes and primitive wells. In contrast, this Late Roman feature was carefully engineered, positioned high on a hillside and used newly acquired, good-quality masonry.

The research published in the latest issue of Internet Archaeology says that the well's main structure featured facing stones of newly quarried, roughly squared, oolitic limestone blocks, probably from a source near Malton, 30km to the north-east. Curved on their outer surface, the stones were set in carefully defined, regular courses. The base of the well was dish-shaped and composed of triangular limestone slabs set directly on natural clay. The engineering employed suggests an intimate understanding of the subsoil. The masonry lining did however incorporate a former roof finial, the only element from any earlier structure to be reused. The excavation team from the Department of Archaeology at York say its recycling is best interpreted as symbolic rather than opportunistic.

The well contained more than a 1000 pieces of Romano-British pottery, including two almost complete Huntcliff-type jars, and a similar number of animal bone fragments. These featured sheep, cattle, horse, deer and even a young dog. A high proportion of the bones showed signs of being butchered but were not highly fragmented, in contrast to the domestic waste encountered on the rest of the site.

Steve Roskams, Senior Lecturer, said: "It is striking that all of the material found in our well would have been familiar to those inhabiting this landscape. Its construction incorporates a finial which, we argue, probably came from the dismantling of a nearby, good-quality structure. The jars circulated here widely, the Huntcliff-type probably being connected directly to water usage. The other pottery and the animal bones also comprise well-understood 'mundane' elements that were available locally.

"At the same time, there is sufficient evidence to indicate that some of this fairly ordinary material was deliberately placed in the well as symbolic performance. When interpreting such practices, archaeologists often concern themselves with whether they belong to 'Roman' or 'Iron Age' traditions. However, if we are to understand these forms of routine ritual fully, we would do better to look to local agricultural cycles and fertility practices, whether annual, generational or longer-term transitions. The economic pressures and social tensions, which came to fore at such points, were of far greater significance to these communities as they sought to establish and reinforce their own, immediate identities."

From Science Daily

Breakthrough Could Lead to 'Artificial Skin' That Senses Touch, Humidity and Temperature

Using tiny gold particles and a kind of resin, a team of scientists at the Technion-Israel Institute of Technology has discovered how to make a new kind of flexible sensor that one day could be integrated into electronic skin, or e-skin. If scientists learn how to attach e-skin to prosthetic limbs, people with amputations might once again be able to feel changes in their environments.

The findings appear in the June issue of ACS Applied Materials & Interfaces.

The secret lies in the sensor's ability to detect three kinds of data simultaneously. While current kinds of e-skin detect only touch, the Technion team's invention "can simultaneously sense touch, humidity, and temperature, as real skin can do," says research team leader Professor Hossam Haick. Additionally, the new system "is at least 10 times more sensitive in touch than the currently existing touch-based e-skin systems."

Researchers have long been interested in flexible sensors, but have had trouble adapting them for real-world use. To make its way into mainstream society, a flexible sensor would have to run on low voltage (so it would be compatible with the batteries in today's portable devices), measure a wide range of pressures, and make more than one measurement at a time, including humidity, temperature, pressure, and the presence of chemicals. In addition, these sensors would also have to be able to be made quickly, easily, and cheaply.

The Technion team's sensor has all of these qualities. The secret is the use of monolayer-capped nanoparticles that are only 5-8 nanometers in diameter. They are made of gold and surrounded by connector molecules called ligands. In fact, "monolayer-capped nanoparticles can be thought of as flowers, where the center of the flower is the gold or metal nanoparticle and the petals are the monolayer of organic ligands that generally protect it," says Haick.

The team discovered that when these nanoparticles are laid on top of a substrate -- in this case, made of PET (flexible polyethylene terephthalate), the same plastic found in soda bottles -- the resulting compound conducted electricity differently depending on how the substrate was bent. (The bending motion brings some particles closer to others, increasing how quickly electrons can pass between them.) This electrical property means that the sensor can detect a large range of pressures, from tens of milligrams to tens of grams. "The sensor is very stable and can be attached to any surface shape while keeping the function stable," says Dr. Nir Peled, Head of the Thoracic Cancer Research and Detection Center at Israel's Sheba Medical Center, who was not involved in the research.

And by varying how thick the substrate is, as well as what it is made of, scientists can modify how sensitive the sensor is. Because these sensors can be customized, they could in the future perform a variety of other tasks, including monitoring strain on bridges and detecting cracks in engines.

Read more at Science Daily

Spider Webs Capture Electrically Charged Prey

Similar to electrostatic dust cloths, spider webs attract electrically charged prey. The electricity, in this case, is derived from flapping.

The discovery, outlined in the latest issue of Scientific Reports, could help to explain how spider webs evolved. Light, flexible spider silk easily deforms in the wind and electrostatic charges to aid prey capture. Were it not for such flexibility, the flying insect could just bounce off and zip on its way.

“Electrostatic charges are everywhere, and we propose that this may have driven the evolution of specialized webs,” Victor Manuel Ortega-Jimenez, a UC Berkeley researcher who worked on the study, said in a press release.

Ortega-Jimenez most often studies hummingbird flight, but he had a light bulb moment while playing with his 4-year-old daughter.

“I was playing with my daughter’s magic wand, a toy that produces an electrostatic charge, and I noticed that the positive charge attracted spider webs,” he said. “I then realized that if an insect is positively charged too it could perhaps attract an oppositely charged spider web to affect the capture success of the spider web.”

To test this, he gathered a bunch of cross-spider webs and brought them into his lab. Then, like Dr. Frankenstein, he used an electrostatic generator to charge up dead insects. These included aphids, fruit flies, green-bottle flies and honeybees. Once charged, all were then dropped one by one onto a neutral, grounded web.

“Using a high speed camera, you can clearly see the spider web is deforming and touching the insect before it reaches the web,” he said. Insects without a charge did not do this. “You would expect that if the web is charged negatively, the attraction would increase.”

Microfiber and electrostatic dust cloths utilize a similar process. Because of its structure, microfiber is positively charged. Like a magnet, it can then attract negatively charged dirt and dust. Tiny hooks in the fabric trap the dust in, which is why you often have to rinse, throw out, or vigorously shake such dust cloths after use.

Insect-generated electricity has also been shown to help bees to communicate with plants and vice versa. There’s been a fair amount of focus on electrically charged bees and insects these days, with all kinds of interesting findings like this. (See an electrically charged bee fall into a spider’s web).

The electricity from our perspective is minimal, although insects easily develop several hundred volts of positive charge from the friction of wings against air molecules or by contacting a charged surface. By comparison, we develop several thousand volts of electricity when walking across a rug, or even when petting a cat. That’s why you can get a shock right afterward when you touch something metal, such as a metal doorknob.

Read more at Discovery News

Primeval Underwater Forest Discovered in Gulf of Mexico

Scuba divers have discovered a primeval underwater forest off the coast of Alabama.

The Bald Cypress forest was buried under ocean sediments, protected in an oxygen-free environment for more than 50,000 years, but was likely uncovered by Hurricane Katrina in 2005, said Ben Raines, one of the first divers to explore the underwater forest and the executive director of the nonprofit Weeks Bay Foundation, which researches estuaries.

The forest contains trees so well-preserved that when they are cut, they still smell like fresh Cypress sap, Raines said.

The stumps of the Cypress trees span an area of at least 0.5 square miles (0.8 kilometers), several miles from the coast of Mobile, Ala., and sit about 60 feet (18 meters) below the surface of the Gulf of Mexico.

Despite its discovery only recently, the underwater landscape has just a few years to be explored, before wood-burrowing marine animals destroy the ancient forest.

Closely guarded secret
Raines was talking with a friend who owned a dive shop about a year after Hurricane Katrina. The dive shop owner confided that a local fisherman had found a site teeming with fish and wildlife and suspected that something big was hidden below. The diver went down to explore and found a forest of trees, then told Raines about his stunning find.

But because scuba divers often take artifacts from shipwrecks and other sites, the dive shop owner refused to disclose the location for many years, Raines said.

In 2012, the owner finally revealed the site's location after swearing Raines to secrecy. Raines then did his own dive and discovered a primeval Cypress swamp in pristine condition. The forest had become an artificial reef, attracting fish, crustaceans, sea anemones and other underwater life burrowing between the roots of dislodged stumps.

Some of the trees were truly massive, and many logs had fallen over before being covered by ocean sediment. Raines swam the length of the logs.

"Swimming around amidst these stumps and logs, you just feel like you're in this fairy world," Raines told LiveScience's OurAmazingPlanet.

Primeval forest

Raines reached out to several scientists to learn more about the forest. One of those scientists was Grant Harley, a dendrochronologist (someone who studies tree rings) at the University of Southern Mississippi.

Harley was intrigued, and together with geographer Kristine DeLong of Louisiana State University, set out to discover the site's secrets.

The research team created a sonar map of the area and analyzed two samples Raines took from trees. DeLong is planning her own dive at the site later this year. Because of the forest depth, scuba divers can only stay below for about 40 minutes before coming up.

Carbon isotopes (atoms of the same element that have different molecular weights) revealed that the trees were about 52,000 years old.

The trees' growth rings could reveal secrets about the climate of the Gulf of Mexico thousands of years ago, during a period known as the Wisconsin Glacial period, when sea levels were much lower than they are today. (World's Weirdest Geological Formations)

In addition, because Bald Cypress trees can live a thousand years, and there are so many of them, the trees could contain thousands of years of climate history for the region, Harley said.

"These stumps are so big, they're upwards of two meters in diameter — the size of trucks," Harley told OurAmazingPlanet. "They probably contain thousands of growth rings."

The team, which has not yet published their results in a peer-reviewed journal, is currently applying for grants to explore the site more thoroughly.

Read more at Discovery News

Jul 7, 2013

Biomedical Uses for Hydrogels Explored

It's squishy, synthetic, flexible, mostly water and almost as tough as rubber.

No, it's not "flubber" -- it's a hydrogel, and now scientists at The University of Akron are exploring new biomedical uses for this polymer-based product.

Dr. Jie Zheng, associate professor of chemical and biomolecular engineering, and Dr. Robert Weiss, Hezzleton E. Simmons professor and chair of polymer engineering, are among the most recent to contribute to the growing research of hydrogels, the gelatinous substance that, because of its toughness and plasticity, has several biomedical applications, including cartilage repair, implants for minimally invasive surgery and drug delivery.

Simplifying production process

Since, as Zheng says, "all existing methods to prepare double-network hydrogels involve multiple-step processes, which are tedious and time-consuming," Zheng and his team developed a simple, efficient and one-pot method (in which reactions occur in one as opposed to several pots) to synthesize double-network hydrogels -- that is, hydrogels composed of two networks of polymer chains, one rigid, the other ductile.

Zheng not only made the synthesis of these hydrogels more efficient -- he also made the hydrogels tougher.

Most hydrogels are weak and brittle, "suffering from low mechanical strength, poor toughness, and/or limited extensibility and recoverability," Zheng says.

His hydrogels, however, "exhibit high mechanical properties, excellent recoverable properties, and a unique, free-shapeable property," he says, making them promising replacements for load-bearing soft tissues like cartilage, tendon, muscle and blood vessels.

Weiss also has synthesized a tougher brand of hydrogel, a "shape memory hydrogel," which can be bent and stretched and fixed into temporary shapes. When exposed to an external stimulus, such as temperature, light, moisture, or an electric field, shape memory polymers recover their original, permanent shape.

Useful shape-shifters

Weiss's shape memory hydrogels are thermally actuated, meaning they stretch and change shape when heated, and they retain this temporary shape when cooled.

Biocompatible, shape memory hydrogels have the potential to be used for minimally invasive surgery and drug delivery, Weiss says.

"Shape memory may be useful for deployment of hydrogels in biomedical applications using less invasive methods ... for example, one can implant a compact form of the device that would deploy into the usable shape after it is implanted," he says.

For example, a small form of the shape memory hydrogel may be inserted into the body, where, upon absorbing bodily fluids, it expands into the desired shape of the implant, thus filling a wound or replacing tissue.

The permeable hydrogels can also be loaded with drugs and placed into the body, where the sponge-like gel biodegrades and releases the drugs from its pores.

Weiss and co-author Jinkun Hao published their findings, "Mechanically Tough, Thermally Activated Shape Memory Hydrogels," on Jan. 7, 2013, in ACS Macro Letters.

Read more at Science Daily

How the Brain Creates the 'Buzz' That Helps Ideas Spread

How do ideas spread? What messages will go viral on social media, and can this be predicted?

UCLA psychologists have taken a significant step toward answering these questions, identifying for the first time the brain regions associated with the successful spread of ideas, often called "buzz."

The research has a broad range of implications, the study authors say, and could lead to more effective public health campaigns, more persuasive advertisements and better ways for teachers to communicate with students.

"Our study suggests that people are regularly attuned to how the things they're seeing will be useful and interesting, not just to themselves but to other people," said the study's senior author, Matthew Lieberman, a UCLA professor of psychology and of psychiatry and biobehavioral sciences and author of the forthcoming book "Social: Why Our Brains Are Wired to Connect." "We always seem to be on the lookout for who else will find this helpful, amusing or interesting, and our brain data are showing evidence of that. At the first encounter with information, people are already using the brain network involved in thinking about how this can be interesting to other people. We're wired to want to share information with other people. I think that is a profound statement about the social nature of our minds."

The study findings are published in the online edition of the journal Psychological Science, with print publication to follow later this summer.

"Before this study, we didn't know what brain regions were associated with ideas that become contagious, and we didn't know what regions were associated with being an effective communicator of ideas," said lead author Emily Falk, who conducted the research as a UCLA doctoral student in Lieberman's lab and is currently a faculty member at the University of Pennsylvania's Annenberg School for Communication. "Now we have mapped the brain regions associated with ideas that are likely to be contagious and are associated with being a good 'idea salesperson.' In the future, we would like to be able to use these brain maps to forecast what ideas are likely to be successful and who is likely to be effective at spreading them."

In the first part of the study, 19 UCLA students (average age 21), underwent functional magnetic resonance imaging (fMRI) brain scans at UCLA's Ahmanson-Lovelace Brain Mapping Center as they saw and heard information about 24 potential television pilot ideas. Among the fictitious pilots -- which were presented by a separate group of students -- were a show about former beauty-queen mothers who want their daughters to follow in their footsteps; a Spanish soap opera about a young woman and her relationships; a reality show in which contestants travel to countries with harsh environments; a program about teenage vampires and werewolves; and a show about best friends and rivals in a crime family.

The students exposed to these TV pilot ideas were asked to envision themselves as television studio interns who would decide whether or not they would recommend each idea to their "producers." These students made videotaped assessments of each pilot.

Another group of 79 UCLA undergraduates (average age 21) was asked to act as the "producers." These students watched the interns' videos assessments of the pilots and then made their own ratings about the pilot ideas based on those assessments.

Lieberman and Falk wanted to learn which brain regions were activated when the interns were first exposed to information they would later pass on to others.

"We're constantly being exposed to information on Facebook, Twitter and so on," said Lieberman. "Some of it we pass on, and a lot of it we don't. Is there something that happens in the moment we first see it -- maybe before we even realize we might pass it on -- that is different for those things that we will pass on successfully versus those that we won't?"

It turns out, there is. The psychologists found that the interns who were especially good at persuading the producers showed significantly more activation in a brain region known as the temporoparietal junction, or TPJ, at the time they were first exposed to the pilot ideas they would later recommend. They had more activation in this region than the interns who were less persuasive and more activation than they themselves had when exposed to pilot ideas they didn't like. The psychologists call this the "salesperson effect."

"It was the only region in the brain that showed this effect," Lieberman said. One might have thought brain regions associated with memory would show more activation, but that was not the case, he said.

"We wanted to explore what differentiates ideas that bomb from ideas that go viral," Falk said. "We found that increased activity in the TPJ was associated with an increased ability to convince others to get on board with their favorite ideas. Nobody had looked before at which brain regions are associated with the successful spread of ideas. You might expect people to be most enthusiastic and opinionated about ideas that they themselves are excited about, but our research suggests that's not the whole story. Thinking about what appeals to others may be even more important."

The TPJ, located on the outer surface of the brain, is part of what is known as the brain's "mentalizing network," which is involved in thinking about what other people think and feel. The network also includes the dorsomedial prefrontal cortex, located in the middle of the brain.

"When we read fiction or watch a movie, we're entering the minds of the characters -- that's mentalizing," Lieberman said. "As soon as you hear a good joke, you think, 'Who can I tell this to and who can't I tell?' Making this judgment will activate these two brain regions. If we're playing poker and I'm trying to figure out if you're bluffing, that's going to invoke this network. And when I see someone on Capitol Hill testifying and I'm thinking whether they are lying or telling the truth, that's going to invoke these two brain regions.

"Good ideas turn on the mentalizing system," he said. "They make us want to tell other people."

The interns who showed more activity in their mentalizing system when they saw the pilots they intended to recommend were then more successful in convincing the producers to also recommend those pilots, the psychologists found.

"As I'm looking at an idea, I might be thinking about what other people are likely to value, and that might make me a better idea salesperson later," Falk said.

By further studying the neural activity in these brain regions to see what information and ideas activate these regions more, psychologists potentially could predict which advertisements are most likely to spread and go viral and which will be most effective, Lieberman and Falk said.

Such knowledge could also benefit public health campaigns aimed at everything from reducing risky behaviors among teenagers to combating cancer, smoking and obesity.

"The explosion of new communication technologies, combined with novel analytic tools, promises to dramatically expand our understanding of how ideas spread," Falk said. "We're laying basic science foundations to addressimportant public health questions that are difficult to answer otherwise -- about what makes campaigns successful and how we can improve their impact."

As we may like particular radio DJs who play music we enjoy, the Internet has led us to act as "information DJs" who share things that we think will be of interest to people in our networks, Lieberman said.

Read more at Science Daily