Aug 24, 2013

Sea Ice Decline Spurs the Greening of the Arctic

Sea ice decline and warming trends are changing the vegetation in nearby arctic coastal areas, according to two University of Alaska Fairbanks scientists.

Uma Bhatt, an associate professor with UAF's Geophysical Institute, and Skip Walker, a professor at UAF's Institute of Arctic Biology, contributed to a recent review of research on the response of plants, marine life and animals to declining sea ice in the Arctic.

"Our thought was to see if sea ice decline contributed to greening of the tundra along the coastal areas," Bhatt said. "It's a relatively new idea."

The review appeared in a recent issue of Science magazine. It is a close, comprehensive look at how the losses of northern sea ice affect surrounding areas. Bhatt and Walker were two of ten authors.

The review team analyzed 10 years worth of data and research on the subject. The findings show that sea ice loss is changing marine and terrestrial food chains. Sea-ice disappearance means a loss of sea-ice algae, the underpinning of the marine food web. Larger plankton is thriving, replacing smaller, but more nutrient dense plankton. What that means exactly is not yet understood.

Above water, loss of sea ice has destroyed old pathways of animal migration across sea ice while opening new pathways for marine animals in others. Some animals and plants will become more isolated. In the case of the farthest north and coldest parts of the Arctic, entire biomes may be lost without the cooling effects of disappearing summer sea ice.

Walker, a plant biologist, says warming soils provide an opportunity for new vegetation to grow where less vegetation occurred previously. This contributes to a general greening of the Arctic that is visible from space. Bhatt, an atmospheric scientist, examined a 1982-2010 time series of remote sensing data to examine trends in sea ice, land-surface temperatures and changes in the vegetation abundance.

A surprise and puzzling finding shows that despite a general warming and greening of Arctic lands in North America, some areas in northern Russia and along the Bering Sea coast of Alaska are showing recent cooling trends and declines in vegetation productivity.

"We don't know why," Bhatt said.

Read more at Science Daily

Underwater Intelligence: How Do You Track a Fish Underwater?

How do you track a fish? There's no "Google Maps" for finding fish. The radio signals that are the backbone of traditional GPS cannot pass through seawater. But sound travels remarkably well, so scientists often use acoustic telemetry to estimate an individual fish's location. That means attaching an acoustic transmitter to a fish and then using a network of stationary underwater listening stations to monitor for the short clicking sounds that these tags emit. When a fish swims near to a receiver, its click is heard, and its individual code number is recorded.

Knowing your uncertainty

Even with this clicker-listener observation network in place, though, there's much uncertainty about a fish's whereabouts at any given time. To date, most researchers have used ad hoc methods to analyze their data, and typically have not quantified uncertainty.

"In science, knowing how certain or uncertain you are is often the prime objective," said Kevin C. Weng, manager of the Pelagic Fisheries Research Program at the University of Hawai'i at Mānoa and a graduate faculty member in the Department of Oceanography. "We're used to knowing within 20 feet where you can find that bison, wolf or bird. But underneath the ocean surface, we don't have the luxury of using GPS. So marine scientists use sound, which results in much lower accuracy."

But what is that accuracy? Martin W. Pedersen, a UH Mānoa postdoctoral fellow from Denmark, explains: "In the traditional tracking system, a fish is generally assigned the position of the receiver that detected it, even though the fish might be anywhere in that receiver's detection range. And if none of the receivers have heard from the fish for a while, no positions are assigned, even though the network may be providing some, albeit uncertain, information about the fish's whereabouts. For example, we could possibly estimate how far a fish could travel in a certain time since it was last heard, and could also infer locations where it isn't, due to the lack of detections."

A new statistical framework

Rethinking the traditional, ad hoc approach, Pedersen and Weng have proposed a new state-space model for analyzing fish movement data collected by marine observation networks. Their new model was recently published in the scientific journal Methods in Ecology and Evolution. Its goal is to quantify the uncertainty associated with this imperfect locating system, and to improve its accuracy.

"Previous methods were not formulated with the fish, ocean and acoustics in mind," said Pedersen. "They therefore do not exploit all available information, such as the biology of the fish limiting its range of possible movement."

Pedersen and Weng's new state-space model for estimating individual fish movement is two-part -- one part that models the fish behavior, and one that models the detection of that behavior.

"It tells us how the fish is moving," said Pedersen. "Does the fish swim in straight lines? Does it have a particular home range, or center of attraction, for its movements?"

The second part of the model estimates the likelihood of detecting a fish -- incorporating the detection probability, environmental noise, and both presence and absence data. When receivers are located close to each other, it can even help researchers triangulate positions. Acoustic telemetry works in much the same way that cell tower networks pin down the location of your mobile phone: The distance from your phone (or the fish tag) to several cell towers (or acoustic receivers) is measured, and circles of that radius are drawn around each tower (receiver). Where the circles intersect -- that's you (or the fish).

The observation model also uses negative data, or the lack of detections, in combination with the behavior model to estimate how far the fish may have traveled while undetected. "Knowing where the fish is not located actually tells you a lot about where it is located, and with our new method, we are able to utilize that information and achieve a better accuracy," Pedersen said.

Does it work in the real (underwater) world?

To field-test their model, the researchers turned to the spectacular tropical reef setting of Palmyra atoll in the central Pacific Ocean -- home to myriad fish, sharks, manta rays, whales and turtles.

With monitoring data collected for coral reef fish from 51 underwater observer stations at Palmyra Atoll, Pedersen and Weng used their state-space model to develop contour maps that provided a visual representation of the confidence regions for the locations of the fish over time, along with a home range estimate.

During daylight hours, fish locations were estimated with a 95% confidence region radius of 50 meters, at their most accurate.

Read more at Science Daily

Aug 23, 2013

A Fluffy Disk Around a Baby Star

An international team of astronomers that are members of the Strategic Exploration of Exoplanets and Disks with Subaru Telescope (SEEDS) Project has used Subaru Telescope's High Contrast Instrument for the Subaru Next Generation Adaptive Optics (HiCIAO) to observe a disk around the young star RY Tau (Tauri). The team's analysis of the disk shows that a "fluffy" layer above it is responsible for the scattered light observed in the infrared image. Detailed comparisons with computer simulations of scattered light from the disk reveal that this layer appears to be a remnant of material from an earlier phase of stellar and disk development, when dust and gas were falling onto the disk.

Since 2009, the five-year SEEDS Project (Note) has focused on direct imaging of exoplanets, i.e., planets orbiting stars outside of our Solar System, and disks around a targeted total of 500 stars. Planet formation, an exciting and active area for astronomical research, has long fascinated many scientists. Disks of dust and gas that rotate around young stars are of particular interest, because astronomers think that these are the sites where planets form--in these so-called "protoplanetary disks." Since young stars and disks are born in molecular clouds, giant clouds of dust and gas, the role of dust becomes an important feature of understanding planet formation; it relates not only to the formation of rocky, Earth-like planets and the cores of giant Jupiter-like planets but also to that of moons, planetary rings, comets, and asteroids.

As a part of the SEEDS Project, the current team of researchers used HiCIAO mounted on the Subaru Telescope to observe a possible planet-forming disk around the young star RY Tau. This star is about 460 light years away from Earth in the constellation Taurus and is around half a million years old. The disk has a radius of about 70 AU (10 billion kilometers), which is a few times larger than the orbit of Neptune in our own Solar System.

Astronomers have developed powerful instruments to obtain images of protoplanetary disks, and Subaru Telescope's HiCIAO is one of them. HiCIAO uses a mask to block out the light of the central star, which may be a million times brighter than its disk. They can then observe light from the star that has been reflected from the surface of the disk. The scattered light will reveal the structure of the surface of the disk, which is very small in scale and difficult to observe, even with large telescopes. Observers use HiCIAO with a 188 element adaptive optics system to reduce the blurring effects of Earthʼs atmosphere, making the images significantly sharper.

This team succeeded in capturing a near-infrared image (1.65 μm) associated with the RY Tau disk. Unlike many other protoplanetary disks, the disk emission is offset from the centre of the star. In contrast to longer wavelength observations, which are associated with the midplane of the disk, near-infrared, scattered light coming from the surface of the disk produced this offset, which provides information about the vertical structure of the disk.

Changes in structure perpendicular to the surface of a disk are much harder to investigate because there are few good examples to study. Therefore, the information about vertical structure that this image provides is a contribution to understanding the formation of planets, which depends strongly on the structure of the disk, including structures such as spirals and rings, as well as height.

The team performed extensive computer simulations of the scattered light, for disks with different masses, shapes, and types of dust. They found that the scattered light is probably not associated with the main surface of the disk, which is the usual explanation for the scattered light image. Instead, the observed infrared emission can be explained if the emission is associated with a fluffy upper layer, which is almost transparent and not completely transparent. The team estimated the dust mass in this layer to be about half the mass of Earthʼs Moon.

Read more at Science Daily

Richard III’s Skeleton Came Within Inches of Destruction

Leicester archaeologists have revealed the bones of Richard III came within inches of destruction.

A team from the University of Leicester Archaeological Services (ULAS) have discovered during a second, follow-up dig, a massive disturbance at the Grey Friars site where the bones of the medieval monarch were found last year.

The news comes one year on from when archaeologists began the Search for Richard III at the Grey Friars site on 25 August last year.

During their second excavation at the Grey Friars site last month, the archaeologists found a large area of the church which had been completely destroyed.

The area -- measuring over 5 metres by 10 metres -- was just inches away from Richard III's skull, meaning the remains of the Last Plantagenet King came very close to being destroyed.

The disturbance covers a far larger area than the remnants of the Victorian toilet which were also discovered near Richard's grave during the first dig last year.

Site director Mathew Morris said: "It's a miracle that Richard III's skeleton was where it was. To the east, there is a massive disturbance that has removed all evidence of the church -- which must have come within inches of his head.

"The disturbance is so big we didn't have all of it in the excavation area. We uncovered an area more than 5 metres by 10 metres. We never got to the bottom -- it is at least 1.8 metres deep.

"We don't know what caused it yet. It's possible it was related to the demolition of the Grey Friars church -- or it could have happened any time after the friary was disbanded. Whatever it was, it came very close to removing Richard's head.

"It's entirely possible that because he was underneath the Victorian outhouses, he was protected from it.

"We found some pottery remnants in the area, but until we have examined those we won't have any idea when the disturbance happened."

The team first started digging on the Grey Friars site on 25 August, 2012.

They came across Richard's remains on the very first day -- but didn't exhume the skeleton until they were able to determine where the bones were buried within the friary.

The archaeologists worked with a team of experts from a wide range of disciplines -- including genetics, osteoarchaeology, forensic pathology and genealogy -- to determine the skeleton's identity.

The results revealed that -- beyond reasonable doubt -- the remains were those of the medieval monarch, and the University announced its discovery to a global audience in February.

Read more at Science Daily

Why Can't Humans Regenerate Body Parts?

The idea that some humble life forms on our planet -- jellyfish, corals and the like -- are actually immortal seems to be as compelling as that vintage 1969 "Star Trek" episode about the 5,000-year-old man, born in ancient Mesopotamia, who was still around to meet Captain Kirk and his crew because he was unable to die.

Now, it has surfaced once again in research at the National University of Ireland-Galway's Regenerative Medicine Institute on Hydractinia echinata, a.k.a. the snail fur.

The snail fur is a pinkish mass of spines, tentacles and polyps just 20 to 30 millimeters in length, which makes it small enough to attach itself to the shells of hermit crabs along the Irish and British coast. The snail fur would seem unremarkable, except for one quality: according to Uri Frank, a scientist at the institute, the creature "in theory -- lives forever."

Immortality, though, is a concept that's largely in the eye of the beholder, as we learned from the brouhaha that erupted after a New York Times Magazine article trumpeted a Japanese scientist's assertion that Turritopsis dohrnii, a species of jellyfish, also lived forever. It turns out, though, that what Frank actually is talking about is the snail fur's ability to fully regenerate lost body parts.

"It sounds gruesome, but if it has its head bitten off, it simply grows another one within a few days," the Irish scientist explained in a recent Irish Times article about the research.

That's a little less like the immortal guy on "Star Trek" and a little more like claiming that your 1985 Pontiac Fiero will last forever, as long as you gradually replace all of its parts. But even so, being able to grow your own replacement parts whenever you needed one would a pretty nifty trick.

The snail fur is far from the only creature on the planet to have this ability. Earthworms, starfish, lobsters, snails, salamanders and scores of other creatures can produce their own replacement organs and/or limbs as well. A few mammals can regenerate themselves to a lesser degree as well; two species of African spiny mice, for example, have the ability to regrow lost sweat glands, fur and cartilage.

So if a zebra fish can grow a new tail, why can't we regenerate an arm or leg -- or a kidney or heart -- whenever we need a new one?

For the answer, we have to look at how we grow our bodies in the first place. In the womb, humans are built, piece by piece, by embryonic stem cells, which are highly pluripotent -- that is, able to divide and differentiate into various other sorts of cells, from nerve cells to muscle cells to blood cells.

Creatures that regenerate limbs and organs have stem cells that keep this ability throughout their life cycles. If a salamander’s leg is cut off, for example, its stem cells rush into action and form a fast-growing mass of undifferentiated cells called a regeneration blastema, which eventually will differentiate and form the various structures of a new limb.

But like most mammals, by the time we’re born, those pluripotent cells are replaced by somatic--AKA adult--stem cells, which can maintain and to a limited degree repair the part of the body in which they’re found. Adult stem cells in bone marrow, for example, can make new blood cells, and adult stem cells in the skin can help to replenish its layers. They also can grow scar tissue to seal off a wound. Humans do have some limited regenerative ability as well. We can’t grow back a lost limb, but as a 2013 article in Nature documented, children sometimes are able to grow back fingertips that have been accidentally amputated. And an adult human can regenerate a portion of his or her liver, if that organ is damaged.

Why we and other mammals lose most of our ability to grow new limbs or organs remains unclear. Some researchers believe that it's a natural consequence of our greater complexity as organisms.

It may be, for example, that the genetic mechanisms in our bodies that try to keep cancers from developing also would prevent a blastema from forming. Enrique Amaya, a developmental biologist at the University of Manchester in Great Britain, recently offered a different possible explanation.

Read more at Discovery News

Optical Illusions: Your Brain Is Way Ahead of You

Optical illusions may seem like nothing more than visual trickery. But they are actually a result of our brains trying to predict the future.

When light hits our retina, it takes about one-tenth of a second for our brain to translate that signal into perception. Evolutionary neurobiologist Mark Changizi says this neural delay makes our brains generate images of what it thinks the world will look like in one-tenth of a second. It's not always right.

“Your brain is slow, so you need to basically create perceptions that correct for that delay,” said Changizi, director of human cognition at 2AI Labs.

Creating an image of the very near future probably kept early humans alive because it kept them from bumping into dangerous objects or being attacked by a fast-moving predator.

Click through the following images and see how our ability to predict the future one-tenth of second in advance also messes with your mind.


When images of objects flow across the retina, it activates all these different neurons in our brains. This is the mechanism by which the brain figures out how to extrapolate the next moment.

“When you move through the world, your eyes take snapshots,” said Chingazi. “During that snapshot, as something moves across your visual field, you don’t just end up with a dot on your retina, you end up with a blurred line on your retina.”

Our perception doesn’t see them, but the blurred lines make our brains realize that something is in motion. From there we can determine the direction of an object moving in our world. Since the blurred lines are all emanating from a single point in your visual field, they can inform you on the direction you’re going.

“Once you know the direction you’re going, you can determine how all these things would change in the next moment,” said Chingazi.

Take the above photo of “warp speed.” You don’t even have to question in what direction those blurred lines are taking you. Little did you know, "Blurred Lines" is more than just the most over-hyped song of the summer.


Perhaps the best representation of blurred lines and how they apply to optical illusions is the Hering illusion. Its radial spokes are blurred lines, all emanating from a single point. Those lines tell us where we are heading: forwards, towards the center.

The reason the two vertical lines appear to bow in the middle is because the radial lines suck our field of vision towards the center, as if we were in motion. In fact, those vertical lines are parallel, despite what our brain tells us. Our perception is actually showing us what those parallel lines look like in the next tenth of a second, the moment our gaze “passes through” the vertical lines, towards the vanishing point of the radial lines.

To simplify things, Chingazi suggests we imagine walking through a very tall doorway of a cathedral. When we’re really far away, the doorway sides seem parallel to one another. The angular distance between the top, middle and bottom of the door are all roughly the same.

“Once you’re really close or going through the cathedral doorway, the parts at eye-level are going to be wider apart,” he said. “When you look up, they actually converge like railroad tracks in the sky.”

Essentially, this is the same phenomenon that happens in the Hering illusion.


Shapes aren’t the only objects that change as we move forward. Other factors like angular size -- how much of our visual field is taken up by an object – speed, distance and the color contrast between an object and its background also contribute to optical illusions.

Changizi determined that many illusions can be defined within his future-seeing process, so he created a chart with 28 categories that help organize what he calls his “grand unified theory.”

“This seven-by-four table really has one hypothesis that explains them all,” he said. “It makes a prediction across these 28 categories about what kind of illusions you should expect and how the illusions will reveal themselves across these 28 kinds of stimuli.”

The above illusion was created by a former student of Chingizi’s, and it demonstrates elements of speed, size and contrast. Move your head towards the center and the bright-white center appears to quickly fill the circle. Move your head backward and the dark perimeter appears to close in on the white center.


The orange circle on the left appears much smaller than the one on the right, when in fact they are the same size. This is the classic Ebbinghaus illusion, named after Hermann Ebbinghaus, the German psychologist who discovered it. British psychologist Edward Titchener popularized the illusion in the early 20th Century, as the illusion is also known as “Titchener circles.”

The juxtaposition of the circles’ sizes and distance from each other make them appear incongruent.

Read more at Discovery News

Aug 22, 2013

Wolves Howl Out of Loneliness

The “woe is me” sound of a wolf howl is tied to loneliness and affection for others, a new Current Biology study suggests.

What’s more, each howl appears to be uniquely matched to the quality of a specific wolf relationship.

This goes against prior speculation that howls are just a knee jerk reaction, with wolves acting out of instinct instead of anything particularly meaningful.

“Our results suggest the social relationship can explain more of the variation we see in howling behavior than the emotional state of the wolf,” Friederike Range of the Messerli Research Institute at the University of Veterinary Medicine Vienna, who worked on the study, said in a press release.

“This suggests that wolves, to a certain extent, may be able to use their vocalizations in a flexible way.”

Range and colleagues’ study looked at two packs of wolves living at Austria’s Wolf Science Center. Human handlers there typically take individual wolves out for walks on a leash, one at a time. The handlers noticed that, without fail, the other wolves would howl when one of their pack left them.

The researchers measured the howling wolves’ stress hormone levels to see if sheer anxiety led to the howling. They found that the amount of howling did not correspond to higher levels of the stress hormone cortisol.

Range said, “Our data suggest that howling is not a simple stress response to being separated from close associates but instead may be used more flexibly to maintain contact and perhaps to aid in reuniting with allies.”

Collected data on the wolves’ dominance status in the pack and their preferred partners determined that wolves howled longer and with more gusto when the missing wolf was a close compatriot and if the individual was of high status within the pack.

Read more at Discovery News

New Glue-Spitting Velvet Worm Found in Vietnam

Small bugs of the rain forest have many things to worry about, assuming they are capable of anxiety. But surely some of their more feared predators are velvet worms, a group of ancient animals that spit an immobilizing, gluelike material onto prey before injecting them with saliva and chomping down.

It turns out the velvet worm family is more diverse than thought: A new species has been found in the jungles of Vietnam. Unlike related velvet worms, this species has uniquely shaped hairs covering its body. It reaches a length of 2.5 inches (6 centimeters), said Ivo de Sena Oliveira, a researcher at the University of Leipzig, Germany, who along with colleagues describes the species in Zoologischer Anzeiger (A Journal of Comparative Zoology).

The paper and related work by Oliveira suggest thousands of unknown species of these creatures are waiting to be found throughout the world's tropical rain forests, he said. Research by Oliveira in the Amazon rain forest alone suggests there may be one new species of velvet worm about every 15 miles (25 kilometers), he told LiveScience.

Little-known glue-spitter

The animals are extremely difficult to find and little known, because they spend most of life hidden in moist areas in the soil, in rotting logs or under rocks, due in part to the fact that their permeable skin allows them to quickly dry out, Oliveira said. In some areas, "if you're not there at the right moment of the year, during the rainy season, you won't find them," he added. The rainy season is the one time of year this Vietnamese species exits the soil, he said.

Unlike arthropods (a huge group of animals that includes ants and spiders), velvet worms lack hard exoskeletons. Instead their bodies are fluid-filled, covered in a thin skin and kept rigid by pressurized liquid. This hydrostatic pressure allows them to walk, albeit very slowly, on fluid-filled, stubby legs that lack joints.


Their slowness works to their advantage. To hunt, they sneak up on other insects or invertebrates. And that's when the sliming begins — velvet worms like the newfound species hunt by spraying a "net of glue" onto their prey from two appendages on their backs, Oliveira said. This nasty material consists of a mix of proteins that impedes movement. "The more the prey moves, the more it gets entangled," he said.

Oftentimes the velvet worms will eat any excess "glue," which is energetically costly to make. Although the animals have been shown to take down prey larger then themselves, they often choose smaller creatures, likely to ensure they don't waste their precious bodily fluids, Oliveira said.

Fossils show that velvet worms haven't changed much since they diverged from their relatives (such as the ancestors of arthropods and waterbears) about 540 million years ago, Oliveira said. Studies of velvet worms could help shed light on the evolution of arthropods, he added.

There are two families of velvet worm, one spread around the tropics, and another found in Australia and New Zealand. Members of the former group generally tend to be loners. But the other family may be more social. One 2006 study found that members of the species Euperipatoides rowelli can hunt in groups of up to 15, and that the dominant female eats first.

While it's not a surprise to find a new species of velvet worm, this is "great work by [these researchers] to actually characterize and name a new species from this region," said Nick Jeffery, a doctoral student at the University of Guelph who wasn't involved in the study.

Read more at Discovery News

Mystery Settlers Reached 'Step to Americas' Before Vikings

One of the first stepping stones for Europeans as they explored across the Atlantic to ultimately land in the Americas was colonized much earlier than previously thought -- and not by the Vikings, who were once thought to be the pioneers of those isles, researchers say.

The Faroe Islands are located about halfway between Norway and Iceland. They were the first stepping stones beyond the Scottish archipelago of the Shetlands for the Viking diaspora that culminated in the European discovery of continental North America in the 11th century, about 400 or 500 years before Christopher Columbus made his famous voyage.

Until now, scientists thought the Vikings undertook the first major settlement of the Faroes in the ninth century. Still, there were hints there might have been earlier arrivals there -- for instance, in about 825, the Irish monk Dicuil in the court of Charlemagne wrote of Irish hermits settling islands beforehand that may have been the Faroes, researcher Mike Church, an environmental archaeologist at the Durham University in England, told LiveScience in an interview.

Mystery settlers

Now, scientists have discovered firm archaeological evidence "for the human colonization of the Faroes by people some 300 to 500 years before the large-scale Viking colonization of the ninth century, although we don't yet know who these people were or where they came from," Church said in a statement.

The research took place at an archaeological site of Á Sondum on the island of Sandoy. The investigation revealed an extensive windblown sand deposit containing patches of burnt peat ash from human activity.

This ash contained barley grains burnt in domestic hearths, which carbon dating showed was pre-Viking. Barley is not indigenous to the Faroes, so it must have been either grown or brought to the islands by humans.

"This is the first archaeological evidence that proves there were humans there at the Faroes prior to the big Viking colonization event," Church said.

Humans would have spread these ashes onto the sands during the fourth to sixth centuries and sixth to eighth centuries. This practice was often seen in the North Atlantic region among Europeans during this period to stabilize the dunes and keep the wind from eroding them away.

"The majority of archaeological evidence for this early colonization is likely to have been destroyed by the major Viking invasion, explaining the lack of proof found in the Faroes for the earlier settlement," Church said.

It remains unknown who these newly discovered settlers were. Possibilities may include religious hermits from Ireland, late-Iron Age colonists from Scotland or pre-Viking explorers from Scandinavia. (The 10 Most Intrepid Explorers)

"Maybe these were intrepid explorers arriving from each of those areas," Church said, adding that the findings raise more questions than they answer.

"Although we don't know who the people were that settled here and where they came from, it is clear that they did prepare peat for use by cutting, drying and burning it, which indicates they must have stayed here for some time," researcher Símun Arge, of the National Museum of the Faroe Islands, said in a statement.

Questions of human settlement

The research challenges the scale, timing and nature of human settlement of the wider North Atlantic region.

"This also raises questions about the timing of human activity on other island systems where, similarly, evidence may have been destroyed," Church said.

Arge agreed. "We now have to digest these dates of this early evidence in relation to other sources and consider whether there may be other similar sites, elsewhere on the islands, which may be able to provide us with further structural archaeological evidence," Arge said.

It may be a major challenge finding more evidence of these ancient settlers, Church noted.

Read more at Discovery News

Brilliant Red Sprite Lightning Caught on Film

Amazing new photos and video of the elusive red lightning called sprites are helping researchers understand how the mysterious electric bursts form.

Sprites last less than a second as they dance on the tops of thunderstorms. Many viewers say the clusters of charged particles look like jellyfish — big, red balls with tendrils that reach down into the clouds. But red sprites take many shapes, from crowns to carrots, and researchers still don't why. Because few sprites are seen from the ground, thanks to obscuring storms, scientists are hunting them from the air.

Graduate student Jason Ahrns captured stunning images of sprites during several flights over the Midwest this summer aboard the National Center for Atmospheric Research's Gulfstream V research plane. Ahrns is part of a sprite-hunting team from University of Alaska, Fairbanks, the U.S. Air Force Academy and Fort Lewis College in Durango, Colo.

During the research flights, the scientists snapped high-speed photos and video, which will help them to better understand the chemical and physical processes behind the phenomenon.

"It's still not clear what exactly is happening in a sprite, and why there are different kinds of sprites," Ahrns told LiveScience in an email interview.

Sprites could also impact weather and climate by changing conditions in Earth's atmosphere, but scientists don't yet know the scale of the effect, Ahrns said. "We can't answer that without studying them."

While many questions remain about red sprites, some details have emerged since their existence was confirmed in 1989. Sprites form above thunderstorms, when a positively charged lightning bolt leaves the air above a thundercloud that is negatively charged. (Most lightning results from negatively charged bolts). The red color results from the interaction between charged particles and nitrogen, scientists believe.

"There's about one positive lightning stroke for every 10 regular negative strokes," said Ahrns, using the technical term for lightning bolt. "Most big storms probably produce a few sprites, and some produce lots of them. They're probably more common than people think, they're just very difficult to see since they're above the clouds."

Red sprites can race high toward space, up to 60 miles (96 kilometers) above the Earth. Astronauts aboard the International Space Station caught a sprite on camera in 2012. A sprite's red tendrils also reach down into the stratosphere, about 15 to 20 miles (25 to 32 km) above Earth's surface. They look brightest between 40 to 45 miles (65 to 72 km) up.

Read more at Discovery News

Aug 21, 2013

Astronomers Take Sharpest Photos Ever of the Night Sky

Astronomers at the University of Arizona, the Arcetri Observatory near Florence, Italy and the Carnegie Observatory have developed a new type of camera that allows scientists to take sharper images of the night sky than ever before.

The team has been developing this technology for more than 20 years at observatories in Arizona, most recently at the Large Binocular Telescope, or LBT, and has now deployed the latest version of these cameras in the high desert of Chile at the Magellan 6.5-meter telescope.

"It was very exciting to see this new camera make the night sky look sharper than has ever before been possible," said UA astronomy professor Laird Close, the project's principal scientist. "We can, for the first time, make long-exposure images that resolve objects just 0.02 arcseconds across -- the equivalent of a dime viewed from more than a hundred miles away. At that resolution, you could see a baseball diamond on the moon."

The twofold improvement over past efforts rests on the fact that for the first time, a telescope with a large diameter primary mirror is being used for digital photography at its theoretical resolution limit in visible wavelengths -- light that the human eye can see.

"As we move towards shorter wavelengths, image sharpness improves," said Jared Males, a NASA Sagan Fellow at the UA's department of astronomy. "Until now, large telescopes could make the theoretically sharpest photos only in infrared -- or long wavelength -- light, but our new camera can take photos that are twice as sharp in the visible light spectrum."

These images are also at least twice as sharp as what the Hubble Space Telescope can make, because with its 21-foot diameter mirror, the Magellan telescope is much larger than Hubble with its 8-foot mirror. Until now, Hubble always produced the best visible light images, since even large ground-based telescope with complex adaptive optics imaging cameras could only make blurry images in visible light.

To overcome atmospheric turbulence, which plagues earth-based telescopes by causing the image to blur, Close's team developed a very powerful adaptive optics system that floats a thin (1/16th of an inch) curved glass mirror (2.8 feet across) on a magnetic field 30 feet above the telescope's primary mirror.

This so-called Adaptive Secondary Mirror (ASM) can change its shape at 585 points on its surface 1,000 times each second, counteracting the blurring effects of the atmosphere.

"As a result, we can see the visible sky more clearly than ever before," Close said. "It's almost like having a telescope with a 21-foot mirror in space."

The new adaptive optics system, called MagAO for "Magellan Adaptive Optics," has already made some important scientific discoveries, published today in three scientific papers in the Astrophysical Journal. As the system was being tested and received what astronomers call "first light," the team pointed it to a famous and well-studied massive star that gives the Great Orion Nebula (Object M42) most of its UV light. The Orion Nebula, located just below Orion's Belt visible as smudge of light even with regular binoculars.

Considered young at about 1 million years old, this star, called Theta 1 Ori C, has been previously known to be in fact a binary star pair made up of two stars called C1 and C2. However, the separation between the two is so small -- about the average distance between Earth and Uranus -- that astronomers had never been able to resolve the famous pair in a direct telescope photo.

Once MagAO and its visible science camera called VisAO were pointed towards Theta Ori 1 C, the results were immediate.

"I have been imaging Theta 1 Ori C for more than 20 years and never could directly see that it was in fact two stars," Close said. "But as soon as we turned on the MagAO system it was beautifully split into two stars."

In another result, MagAO has shed light on another mystery: How do how planets form from disks of dust and gas affected by the strong ionizing light called stellar wind coming from a massive star like Theta 1 Ori C, which has about 44 times the mass of the sun?

The team used MagAO and VisAO to look for red light from ionized hydrogen gas to trace out how the strong UV radiation and stellar wind from Theta 1 Ori C affects the disks around its neighboring stars.

"Close to Theta 1 Ori C, there are two very young stars surrounded by disks of gas and dust," said Ya-Lin Wu, a graduate student and lead author on one of the publications. "Theta 1 Ori C pummels those disks with stellar wind and UV light. It looks like they are being bent backwards by a strong wind."

MagAO's photo revealed that the two stars and their protoplanetary disks are heavily distorted into teardrop shapes as the strong UV light and wind create shock fronts and drag gas downwind of the pair.

The distribution of gas and dust in young planetary systems is another unsolved problem in planet formation. The team used VisAO's simultaneous/spectral differential imager, or SDI, to estimate the mass of another intriguing object in the Orion Nebula: one of a few stars in Orion sporting a rare "silhouette disk." The SDI camera allowed the light from the star to be removed at a very high level -- offering, for the first time, a clear look at the inner regions of the silhouette.

"The disk lies in front of the bright Orion nebula, so we see the dark shadow cast as the dust in the disk absorbs background light from the nebula," said Kate Follette, a graduate student and lead author of one of the three papers published in the Astrophysical Journal. "Picture a moth flying across a bright movie screen: Its body will appear opaque, while the wings will be partially transparent. Our SDI instrument allows us to peer into the silhouette and trace how much dust is at each location in the disk based on how transparent or opaque it is."

"We were surprised to find that the amount of attenuated light from the nebula never reached an opaque point," she said. "It seems as though the outer parts of this disk have less dust than we would have expected."

"It is important to understand how dust is laid out in these objects because that dust and gas is what nature uses to build planets," Close explained. "Our new imaging capabilities revealed there is very little dust and gas in the outer part of the disk."

Read more at Science Daily

Medieval Poison Ring Used for Political Murders

Bulgarian archaeologists have unearthed a medieval bronze ring that might have been used for political murders some 700 years ago, local authorities have announced.

Found at the site of a former medieval fortress in Cape Kaliakra, not far from the Black Sea coastal town of Kavarna in northeast Bulgaria, the finely crafted ring was probably worn by a male on the little finger of the right hand.

Intriguingly, it features a round, hollow cartridge decorated with granulation and an artificial hole.

“The cartridge was adapted into the ring for the poison to be poured into a glass quite seamlessly,” the Kavarna municipality said in a statement.

Dated to the 14th century, the poison ring adds to more than 30 gold rings, earrings with pearls and other jewels found at the site since 2011.

But according to Bonnie Petrunova, head of the dig and deputy director of the National Archaeology Institute and Museum in Sofia, that piece of jewelry has no comparison in the whole of Bulgaria.

“It’s a unique ring,” Petrunova said. “I have no doubts that the hole is there on purpose and the ring was worn on the right hand, because the hole was made in such a way so as to be covered by a finger, thus the poison could be dropped at a moment’s notice.”

“Clearly, it was not worn constantly and would have been put on when necessary,” he added.

Possibly coming from Italy or Spain, with which Bulgarian principalities had trade relations, the deadly poison was used for political murders.

Worn at a time in which Kaliakra was the capital of a principality in the Dobruja region, the poison ring most likely had a key role in the fight between Dobrotitsa, ruler of the independent Despotate of Dobrudja in the second half of the 14th century, and his son Ivanko Terter, Petrunova said.

Read more at Discovery News

Ancient Artificial Harbor Found in Israel

Archaeologists say they have discovered massive fortifications on the coast of Israel that may have protected an Assyrian artificial harbor during the Iron Age more than 2,700 years ago.

Researchers from Tel Aviv University (TAU) unearthed the crescent-shaped structure in the Israeli city of Ashdod, just south of Tel Aviv. The impressive fortifications date back to the eighth century B.C. At their core is a mud-brick wall that measures more than 12 feet (3.6 meters) wide and 15 feet (4.5 m) high. This wall is covered in layers of mud and sand extending outward hundreds of feet.

"The fortifications appear to protect an artificial harbor," TAU archaeologist Alexander Fantalkin said in a statement. "If so, this would be a discovery of international significance, the first known harbor of this kind in our corner of the Levant."

The researchers are not exactly sure who built the defensive structure, but they think it may be associated with a rebellion.

From ancient Assyrian inscriptions, researchers have gleaned that a rebel king of Ashdod named Yamani led a revolt against Sargon II, the king of the empire, around the time the fortifications were built. Sargon II's forces quickly put down the rebellion. Whereas some researchers have conjectured that the rebels put up the fortifications in anticipation of a fight, Fantalkin said the construction is too huge to have been completed under hasty circumstances.

"An amazing amount of time and energy was invested in building the wall and glacis (embankments)," Fantalkin added.

The excavations are taking place at the site of Ashdod-Yam, and researchers say there are more layers of the site's archaeological history.

Read more at Discovery News

Stars' Twinkle Reveals Potential for Habitable Worlds

In 1806, English poet Jane Taylor famously lamented that a little star’s twinkle, twinkle left her wondering what it was.

Fast-forward 207 years and a new analysis of starlight collected by NASA’s Kepler space telescope shows patterns in the flicker that are directly tied to the amount of boiling taking place on a star’s surface, a key indicator of its size, mass and evolutionary state.

That information, in turn, reveals volumes about any orbiting planets, including those fortuitously positioned from their parent stars for liquid surface water -- apparently a key ingredient for life.

“Everything you know about planets is tied to what you know about the host star,” Fabienne Bastien, an astronomy graduate student at Vanderbilt University, told Discovery News.

“We don’t observe the planets directly. We observe the stars and the influence that the planets have on their stars so in order to make any conclusions about the size of the planet or the mass of the planet as it’s pulling on the star when it’s moving, you need to know the size and the mass of the star very well.

“That directly impacts whether or not you can claim that you have an Earth-like planet,” she said.

Bastien, who is working on a doctoral dissertation, was analyzing archived Kepler data for a totally different reason when she and colleagues chanced upon strange patterns in the data that they didn’t understand.

“It was a complete surprise,” Bastien said.

It turns out the pattern provides a quick and relatively reliable way to determine a star’s evolutionary state. Stars like the sun, which is about 4.6 billion years old, eventually will evolve into red giants as they run out of fuel for nuclear fusion. The new study shows the surfaces of younger dwarf stars boiling more vigorously than older giants.

“What we are looking at here is the gravitational acceleration in the stellar outer layers, what we often call the atmosphere,” astronomer Joergen Christensen-Dalsgaard, with Aarhus University in Denmark, wrote in an email to Discovery News.

“The typical methods used have uncertainties up to 150 percent. That very imprecise method is the easiest to do, and especially if you’re dealing with 150,000 stars and you need to characterize them all, that’s what you go to because it takes the least amount of resources. Our technique lets us beat that down to 25 percent, which is very, very good for this field,” added Bastien.

Kepler, which collected data from about 120,000 target stars between May 2009 and May 2013, was designed to search for Earth-like planets in stars’ habitable zones,

For Bastien’s study, which appears in this week’s Nature, astronomers analyzed a few thousand stars in the Kepler data archive.

Read more at Discovery News

Aug 20, 2013

Oldest 'Bog Body' Found with Skin Intact

Archaeologists have unearthed the remains of a 4,000-year-old man preserved in an Irish peat bog, marking the oldest European body ever found with skin still intact.

The cool, waterlogged conditions of Northern European bogs (a type of wetland) create low-oxygen, highly acidic environments ideal for body preservation. As a result, hundreds of "bog bodies" dating back thousands of years have been uncovered in the region, but many have shriveled down to mostly skeletons and tend to be closer to 2,000 years old.

A resident of central Ireland's County Laois came across the well-preserved "Cashel Man" -- named for the bog he was found in -- while milling for peat moss, which is used for a variety of farm purposes, including animal-bedding and field conditioning.

Having realized that he had come across a human body, the resident notified archaeologists at the National Museum of Ireland, who later conducted a formal excavation of the site. A summary of the dig appeared in the latest edition of the Irish journal Ossory, Laois, and Leinster.

"All that was visible to start with was a pair of legs below the knees, and a torso," Eamonn Kelly, an archaeologist at the National Museum and lead excavator of the project, wrote in the report. "The body appeared to be naked. Later, it was possible to work out that the torso had been damaged by the milling machine, which also removed the head, neck and left arm."

The team calculated the age of the body using radiometric carbon dating, in which the constant decay rate of radioactive carbon-14 is used to estimate age based on remaining levels of carbon-14 in the dead tissues. Surprised to find the body was roughly 4,000 years old, the team dated the peat above and below the body to confirm the results, and came up with about the same age. Previously, the oldest bog body ever found in Ireland was 1,300 years old, according to the Irish Times.

The team conducted computed tomography (CT) scans of the body after the dig, and found that the young man's arm and spine had been broken multiple times, seemingly from sharp blows before his death.

The researchers also found cuts along the man's back that looked like ax wounds. They uncovered axes capable of producing such wounds within the vicinity of the site.

Given this evidence of brutality, the team concluded that the young man had been killed in a ritual sacrifice, a practice commonly known in later eras, but not well documented in the Early Bronze Age of 2000 B.C., about the time this bog body would've lived.

"All the indications are that the human remains from Cashel Bog tell of the fate of a young king who, through folly or misadventure, was deemed to have failed to appease the goddess on whose benevolence his people depended, and who paid the ultimate price," Kelly wrote.

The international anthropology community has also taken note of the significance of this finding.

Read more at Discovery News

Oceanic Black Holes Found in Southern Atlantic

Black holes are a tear in the fabric of space-time from which nothing escapes, not even light. They take on a mythic significance in popular culture as portals to alternate dimensions or grave threats to space travel. Astronomers are certain they exist out there in the universe, formed by the collapse of dead stars.

Now, physicists have found mathematical analogs to black holes here on Earth, specifically in the southern Atlantic Ocean where eddies whirl about. The work was posted to arXiv and reported first by the The Physics arXiv Blog.

The scientists describe the eddies using Edgar Allan Poe’s “A Descent into the Maelström”:

“The edge of the whirl was represented by a broad belt of gleaming spray; but no particle of this slipped into the mouth of the terrific funnel. . .”

That’s exactly how eddies look, the study says. A belt of spray encircles the whirlpool but the liquid does not fall in.

Similarly, black holes in space are encircled by photon (light) spheres, a region where the gravity is so strong (because of the density of the black hole) that it causes light to travel in an orbit. And there the photons remain, in precarious balance, neither falling into the hole or escaping. That’s similar to Poe’s description of the belt of spray around the Maelström.

And much like astronomical black holes, oceanic eddies exhibit singularity.

To locate these oceanic black holes, the scientists examined satellite images of the Agulhas Current in the Indian Ocean. The current travels along the east coast of Africa before turning back on itself in a loop. The loop occasionally pinches off and forms eddies that whirl off into the South Atlantic Ocean, remaining intact for more than three months.

The eddies are a coherent island of water in an otherwise turbulent ocean. As such, they “create moving oases for the marine food chain or even impact climate change through their long-range transport of salinity and temperature,” the study states. The eddies will capture any detritus floating nearby and swallow it, thereby transporting oil and garbage. And nothing within leaks out.

Read more at Discovery News

Spontaneous Human Combustion? Probably Not

Earlier this month a 4-month-old Indian boy was admitted to a hospital with burns on his chest, head and abdomen. Though police and medical suspicions first turned to parental abuse or neglect in the child’s injuries, the baby’s mother offered a strange explanation.

She claimed that Rahul had previously been injured by a mysterious phenomena called spontaneous human combustion (SHC), in which people are said to suddenly and inexplicably burst into flames.

She claimed that there was nothing flammable near him when he was burned and suggested that there may be something special or unique about the boy’s body chemistry that makes him prone to these strange attacks.

According to R. Jayachandran, a professor in the department of pediatrics at Kilpauk Medical College Hospital in Chennai, “The mother told us that the baby has suffered four episodes of such spontaneous fire and suffered burn injuries. The last episode was a month back.”

His parents claimed that Rahul first caught fire when he was nine days old. There is surely something strange going on with this child — but what?

Spontaneous Human Combustion?

The idea that people can suddenly burst into flames for no apparent reason has been around for over a century; it even happened to a character in the 1853 Dickens novel “Bleak House.”

Some sources claim that hundreds, or even thousands, of spontaneous combustion cases have been reported throughout history, though only about a dozen cases have been investigated.

There are many reasons to be skeptical that random people can spontaneously combust. Not only is there no plausible medical or physiological mechanism by which a person could generate enough heat to catch fire, but there exists no film or video evidence of it ever occurring.

With few exceptions, SHC cases follow a familiar pattern upon close investigation: elderly, young, or infirm people left alone in or near flammable materials and sources of ignition.

Despite a lack of credible evidence for the existence of SHC, belief in the phenomenon is widespread, and every few years a suspected case makes the news. In fact in 2011 an Irish coroner even officially listed it as a cause of death in the case of a 76-year-old man found dead lying near an open fire.

Police, understandably, take a dim view of supernatural or paranormal “explanations” for real-life injuries and crimes. Injuries to anyone — and especially children — blamed on ghosts should of course be treated with extreme skepticism; other than in scary movies and reality TV ghost shows, real injuries are caused by real people. If a child goes missing investigators assume abductions by family members, not aliens or Bigfoot.

In the case of the Indian toddler, follow-up tests found nothing unusual about Rahul.

“Over a dozen tests have been performed on the baby to check the vital functions and according to doctors the reports so far are normal,” according to a report from ZNews India. Though tests on the child turned up nothing unusual, investigators did locate a hidden source of flammable material in the huts where the family lived.

Read more at Discovery News

Blue Moon Rises: What Does It Mean?

When the moon rises Tuesday night (Aug. 20), it brings us the August full moon and in addition, it will also technically be a "Blue Moon."

"But wait a minute," you may ask. "Isn't a Blue Moon defined as the second full moon that occurs during a calendar month? Tuesday’s full moon will be the only full moon of August 2013. So how can we call it a 'Blue' moon?"

Yet it still is a Blue Moon, but only if we follow a now somewhat obscure rule of astronomy. In fact, the current "two full moon in one month" rule has superseded the rule that would allow us to call Tuesday’s full moon "blue."

Confused yet? Well, as the late Paul Harvey used to say, here now, is the rest of the story:

A Blue Moon: The Almanac Moon Rule

Back in the July 1943 issue of "Sky & Telescope magazine, in a question and answer column written by Lawrence J. Lafleur, there was a reference made to the term "Blue Moon." Lafleur cited the unusual term from a copy of the 1937 edition of the now-defunct Maine Farmers’ Almanac (NOT to be confused with The Farmers' Almanac which is still published in Lewiston, Maine).

On the Maine Farmers' almanac page for August 1937, the calendar definition of the Blue Moon explained that occasionally "one of the four seasons would contain four full moons instead of the usual three."

"There are seven Blue Moons in a Lunar Cycle of nineteen years," continued the Almanac, ending on the comment: "In olden times the almanac makers had much difficulty calculating the occurrence of the Blue Moon and this uncertainty gave rise to the expression 'Once in a Blue Moon.'"

Unfortunate Astronomical Oversight

While LaFleur quoted the Almanac's account, he made one important omission: He never specified any date for the Blue Moon. And as it turned out, in 1937 it occurred on Aug. 21. That was the third full moon in the summer of 1937, a summer season that would see a total of four full moons.

Names were assigned to each moon in a season: For example, the first moon of summer was called the early summer moon, the second was the midsummer moon, and the last was called the late summer moon. But when a particular season has four moons the third was apparently called a Blue Moon so that the fourth and final one can continue to be called the late moon.

So where did we get the "two full moons in a month is a Blue Moon rule" that is so popular today?

Pruett's Mistake

Once again, we must turn to the pages of Sky & Telescope. This time to page 3 of the March 1946 issue.

In that issue, author James Hugh Pruett wrote the article "Once in a Blue Moon" in which he made a reference to the term "Blue Moon" and referenced LaFleur's S&T article from July 1943. But because Pruett had no specific dates to fall back on, his interpretation of the ruling given by the Maine Farmers' Almanac was highly subjective. Pruett ultimately came to this conclusion:

"Seven times in 19 years there were — and still are — 13 full moons in a year. This gives 11 months with one full moon each and one with two. This second in a month, so I interpret it, was called Blue Moon."

How unfortunate that Pruett did not have a copy of that 1937 almanac at hand, or else he would have almost certainly noticed that his "two full moons in a single month assumption" would have been wrong. For the Blue Moon date of Aug. 21 was most definitely not the second full moon that month!

Blue Moon Goes Viral

Pruett's 1946 explanation was, of course, the wrong interpretation and it might have been completely forgotten were it not for Deborah Byrd who used it on her popular National Public Radio program, StarDate on Jan. 31, 1980. We could almost say that in the aftermath of her radio show, the incorrect Blue Moon rule "went viral." Over the next decade, this new Blue Moon definition started appearing in such diverse places such as the Kids edition of the World Almanac, and the board game Trivial Pursuit.

I must confess that even I was involved in helping to perpetuate the new Blue Moon phenomenon. More than 30 years ago, in the Dec. 1, 1982 edition of The New York Times, I made reference to it in the "New York Day by Day" column.

And by 1988 the new definition started receiving international press coverage.

Today, Pruett's misinterpreted "two full moons in a month rule" is recognized worldwide. Indeed, Sky & Telescope turned a literary lemon into lemonade, proclaiming later that — however unintentional — it changed pop culture and the English language in unexpected ways.

Meanwhile, the original Maine Farmers' Almanac rule had been all but forgotten.

Playing by the (Old) Rules

Now, let's come back to this August's full moon. Under the "old" Almanac rule, Tuesday's lunar event will be a "Blue Moon."

In northern summer of 2013, there are four full moons: They occur on June 23, July 22, Aug. 20 and Sept. 19.

This means that under the original Maine Almanac rule — the one promoted by Lafleur and later misinterpreted by Pruett — the third full moon of the 2013 summer season on Aug. 20 would be a Blue Moon.

Read more at Discovery News

Aug 19, 2013

Tiny Fish Make 'Eyes' at Their Killer

Small prey fish can grow a bigger 'eye' on their rear fins as a way of distracting predators and dramatically boosting their chances of survival, new scientific research has found.

Researchers from Australia's ARC Centre of Excellence for Coral Reef Studies (CoECRS) have made a world-first discovery that, when constantly threatened with being eaten, small damsel fish not only grow a larger false 'eye spot' near their tail -- but also reduce the size of their real eyes.

The result is a fish that looks like it is heading in the opposite direction -- potentially confusing predatory fish with plans to gobble them up, says Oona Lönnstedt, a graduate student at CoECRS and James Cook University.

For decades scientists have debated whether false eyespots, or dark circular marks on less vulnerable regions of the bodies of prey animals, played an important role in protecting them from predators -- or were simply a fortuitous evolutionary accident.

The CoECRS team has found the first clear evidence that fish can change the size of both the misleading spot and their real eye to maximise their chances of survival when under threat.

"It's an amazing feat of cunning for a tiny fish," Ms Lonnstedt says. "Young damsel fish are pale yellow in colour and have this distinctive black circular 'eye' marking towards their tail, which fades as they mature. We figured it must serve an important purpose when they are young."

"We found that when young damsel fish were placed in a specially built tank where they could see and smell predatory fish without being attacked, they automatically began to grow a bigger eye spot, and their real eye became relatively smaller, compared with damsels exposed only to herbivorous fish, or isolated ones.

"We believe this is the first study to document predator-induced changes in the size of eyes and eye-spots in prey animals."

When the researchers investigated what happens in nature on a coral reef with lots of predators, they found that juvenile damsel fish with enlarged eye spots had an amazing five times the survival rate of fish with a normal-sized spot.

"This was dramatic proof that eyespots work -- and give young fish a hugely increased chance of not being eaten.

"We think the eyespots not only cause the predator to attack the wrong end of the fish, enabling it to escape by accelerating in the opposite direction, but also reduce the risk of fatal injury to the head," she explains.

Read more at Science Daily

Computer Can Read Letters Directly from the Brain

By analysing MRI images of the brain with an elegant mathematical model, it is possible to reconstruct thoughts more accurately than ever before. In this way, researchers from Radboud University Nijmegen have succeeded in determining which letter a test subject was looking at.

The journal Neuroimage has accepted the article, which will be published soon.

Functional MRI scanners have been used in cognition research primarily to determine which brain areas are active while test subjects perform a specific task. The question is simple: is a particular brain region on or off? A research group at the Donders Institute for Brain, Cognition and Behaviour at Radboud University has gone a step further: they have used data from the scanner to determine what a test subject is looking at.

The researchers 'taught' a model how small volumes of 2x2x2 mm from the brain scans -- known as voxels -- respond to individual pixels. By combining all the information about the pixels from the voxels, it became possible to reconstruct the image viewed by the subject. The result was not a clear image, but a somewhat fuzzy speckle pattern. In this study, the researchers used hand-written letters.

Prior knowledge improves model performance

'After this we did something new', says lead researcher Marcel van Gerven. 'We gave the model prior knowledge: we taught it what letters look like. This improved the recognition of the letters enormously. The model compares the letters to determine which one corresponds most exactly with the speckle image, and then pushes the results of the image towards that letter. The result was the actual letter, a true reconstruction.'

'Our approach is similar to how we believe the brain itself combines prior knowledge with sensory information. For example, you can recognise the lines and curves in this article as letters only after you have learned to read. And this is exactly what we are looking for: models that show what is happening in the brain in a realistic fashion. We hope to improve the models to such an extent that we can also apply them to the working memory or to subjective experiences such as dreams or visualisations. Reconstructions indicate whether the model you have created approaches reality.'

Read more at Science Daily

Russian Meteor Explosion's Dust Lingered for Months

When a meteor exploded over the Russian city of Chelyabinsk in February, pieces of the bus-sized space rock hit the ground while its detonation shattered windows, set off car alarms and injured more than 1,000 people.

Masked in the chaos, however, was an enormous plume of dust that the Russian meteor left behind in Earth's atmosphere. This cloud, which had hundreds of tons of material in it, was still lingering three months after the Feb. 15 explosion, a new study has found. Scientists created a video of the Russian meteor explosion's dust cloud to illustrate the phenomenon.

"Thirty years ago, we could only state that the plume was embedded in the stratospheric jet stream," Paul Newman, chief scientist for NASA Goddard Space Flight Center's atmospheric science lab, said in a statement. "Today, our models allow us to precisely trace the bolide and understand its evolution as it moves around the globe."

Chasing dust

The Russian meteor, which weighed 11,000 metric tons when it hit the atmosphere, detonated about 15 miles (24 kilometers) above Chelyabinsk. The explosion sent out a burst of energy 30 times greater than the atom bomb that leveled Hiroshima during World War II.

Some of the asteroid's remnants crashed to the ground, but hundreds of tons of dust remained in the atmosphere. A team led by NASA Goddard atmospheric physicist Nick Gorkavyi, who is from Chelyabinsk, wondered if it was possible to track the cloud using NASA's Suomi NPP satellite.

"Indeed, we saw the formation of a new dust belt in Earth's stratosphere, and achieved the first space-based observation of the long-term evolution of a bolide plume," Gorkavyi said in a statement.

Initial measurements 3.5 hours after the meteor explosion showed the dust 25 miles (40 km) high in the atmosphere, speeding east at 190 mph (306 km/h).

Russian officials were still cleaning up in Chelyabinsk when, four days after the explosion, the higher portion of the plume reached all the way around Earth's northern hemisphere. Even three months into the study, Suomi still saw a "detectable belt" of dust circling the globe, researchers said.

Putting it in perspective

Tracking the plume also revealed some insights into how particles behave in Earth's atmosphere. Heavier particles, for example, moved more slowly as they dropped closer to Earth in an area with lower wind speeds. Lighter particles maintained speed and altitude, consistent with predictions of wind velocities at their heights.

While the plume was easily detectable, it was by no means extraordinarily dense, NASA researchers noted. About 30 metric tons of space dust hits the Earth every day on average. Also, volcanoes and other natural Earth sources contribute far greater numbers of particles to the stratosphere.

Read more at Discovery News

First Fossil Whale Poop Pops Up in Italy

Clumps of squid beaks sticking out of clay in Italy's Umbrian badlands may be the first fossilized ambergris, or whale poo, ever found.

Ambergris is a fatty, waxy-looking substance. Scientists believe sperm whales — the largest toothed predator on Earth — secrete ambergris inside their digestive tracts to protect themselves from sharp objects, like giant squid beaks and fish bones and teeth. And contrary to urban legend, ambergris is actually whale poo, not vomit. Sought after by perfume makers, aged ambergris is like umami for the nose, adding musky depth to scents.

Even though scientists have discovered fossilized feces, called coprolites, from dinosaurs, ichthyosaurs, mammoths and sharks, no one has reported finding ancient ambergris.

"These structures, derived from the original fossil ambergris masses, represent the first recovery on a global scale, since nothing like has been described before in the scientific literature," lead study author Angela Baldanza, a sedimentary geologist at the University of Perugia in Italy, said in an email interview.

Baldanza and her colleagues discovered the fossil ambergris in September 2011, while surveying the remains of a Pleistocene ocean in southwestern Umbria in central Italy. The region is well known for sperm whale fossils, though few have been found near the site of the fossil ambergris, Baldanza said.

Trekking across the badlands, the scientists noticed mineralized lumps sticking out of the 1.75-million-year-old rocks. They found 25 of the rounded structures over an area of about 0.3 acres (1,200 square meters). Each was about 23 to 47 inches (60 to 120 centimeters) wide and 12 to 23 inches (30 to 60 cm) long. The mounds were circular or tapered.

"The preliminary observations revealed they were of biological origin, but bore no resemblance to any known trace fossil," Baldanza told LiveScience's OurAmazingPlanet. "From the first moment we discovered them, these structures looked enigmatic."

Several clues led the researchers to conclude they had found fossil whale poo. The trace fossils were striated with concentric rings, like modern ambergris, and their rounded and tapered shapes matched the appearance of ambergris found in sperm whales killed on ships in the 1950s. Squid beaks and altered organic matter in the fossils also hinted at an origin in a sperm whale's stomach.

Read more at Discovery News

Aug 18, 2013

Dread Pirate Blackbeard's Wreck Is Coming Up

Sunken treasure lies 25 feet beneath the sea off North Carolina, where archaeologists are probing the wreck of the Queen Anne’s Revenge -- the flagship in the dread pirate Blackbeard’s flotilla.

But this treasure won’t sparkle and gleam, and it definitely isn’t locked in a dead man’s chest.

“The project calls for the recovery of all the materials. Everything. All the weapons, all the bits of the ship, all the personal items. Everything. If it’s down there, it’s coming up,” project leader Billy Ray Morris told

Morris and a group of 14 marine archaeologists, technicians and restoration experts from the Underwater Archaeology Branch of the N.C. Department of Cultural Resources believe the Queen Anne's Revenge itself is a treasure trove, a unique repository of history from centuries ago. They plan to salvage the entire remains of the pirate ship by 2014. Cannon by cannon, plank by plank.

“I’ve worked on shipwrecks all around the world, and this is one of the coolest,” Morris said.

Pulled from the ocean's chemical stew, the artifacts are taken to a lab in Greenville, where it may take as much as a decade to leach out 300 years worth of salt and sea, preparing the ship for the final phase of its life out of the water. More than 280,000 such artifacts have already been recovered; many are displayed in an exhibit at the N.C. Maritime Museum in Beaufort. It will ultimately provide a detailed look at 18th century life, information Morris said is hard to come by.

“It’s not like these guys left their memoirs," he told "We’re looking at the stuff that these guys used on a daily basis.”

The Queen Anne's Revenge ran aground in Beaufort in June 1718, on the western side of the channel. Morris said the ship was most likely intentionally grounded; historical documentation indicates Blackbeard wanted to downsize his flotilla of four ships -- and the crew that sailed on them.

“So there would be fewer guys he had to split the goodies with,” Morris said.

Intersal, Inc., a private research firm, discovered the site in late 1996. The Department of Cultural Resources has been working it ever since, bit by bit. In 2009, they recovered the ship's anchor. The interest is driven in part because this pirate ship was not always a pirate ship: Queen Anne’s Revenge was built as a privateer, then served as a slave ship before coming under Blackbeard’s command.

“We’re going to have a magnificent collection,” Morris told “We’ve got the plates they ate off. We’ve got bones with butcher’s marks.”

A treasure chest is an unlikely find in the wreckage: When you sink your own pirate ship, you pull the loot off it first. But what does exist, 300 years after the ship was abandoned in shallow waters, will be of incalculable value for future scholars, Morris said. There is navigation equipment, weaponry, ceramics, glass wear, personal effects, material from the African slave trade and more. These items often are locked in a concrete like crust of sand, shells and marine life that must be removed during the conservation process.

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Medieval Child's Last Day Revealed With New Tech

Soil surrounding centuries-old skeletons can reveal how the deceased people spent their last day on Earth, according to a new study published in the journal Heritage Science.

Danish researchers used the new technology to investigate the remains of a 10- to 13-year-old child who had been buried in the medieval town of Ribe, in Denmark, some 800 years ago.

According to their findings, the day before death was indeed painful for the poor child, who was likely suffering from a severe illness. In a desperate attempt to save his or her life, the child was given a high dose of bacteria-killing mercury.

“I cannot say which diseases the child had contracted.” Kaare Lund Rasmussen, a chemist from the University of Southern Denmark, said. “But I can say that (the child) was exposed to a large dose of mercury a couple of months before its death and again a day or two prior to death.”

“You can imagine what happened: that the family for a while tried to cure the child with mercury-containing medicine which may or may not have worked, but that the child’s condition suddenly worsened and that it was administered a large dose of mercury which was, however, not able to save its life,” he added.

The detailed insight into the life of the child did not come from analyses of the child’s bones. Rather, Rasmussen and colleagues extracted the crucial information from the soil surrounding the skeletal remains.

The sampling technique relies on the compounds released when a body decays in the grave.

“If we can localize an element in the soil in the immediate vicinity of the skeleton which is not normally found in the soil itself, we can assume that it came from the deceased and this can tell us something about how the person lived. We are not interested in death, but in the life before death,” Rasmussen said.

The soil samples must be taken from the regions once occupied by the individual’s lungs, kidneys, liver and muscle tissue.

For example, the compounds that were originally part of the kidneys have now become part of the soil — provided they have not been washed away by groundwater.

“If there was mercury present in the kidney at the time of death it would have been transformed rapidly to mercury sulphide, which is very immobile and undissolvable in water. In this way we can obtain information about the deceased even though we do not analyze the bones,” Rasmussen said.

Locating the compounds in relation to the decayed organs is very important to get clues about the last days of the deceased. For instance, mercury is excreted very fast from the lungs, within hours or at the most a couple of days.

“When we found high mercury concentrations in the soil that had once been the lungs of the child, we could conclude that the child probably was exposed to mercury within the last 48 hours or so before its death,” Rasmussen said.

Although bones can also be analyzed for excess mercury, the technique has some limitations, according to Rasmussen.

“While the soil gives insight into the last months and days before death, the bones can only give information about the mercury exposure from about 10 to three years prior to death,” he said.

Rarely found naturally in soil, mercury is particularly interesting for archaeologists as many cultures in different part of the world have been in contact with this chemical element.

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CIA Admits 'Area 51' Exists, But Says No UFOs

A newly declassified CIA document confirms the existence of famed Area 51 in Nevada, but conspiracy theorists will be disappointed the spy agency offers no proof of alien spaceship landings in the desert.

Area 51 has long been fodder for science fiction films and wild UFO tales claiming the US government imposed secrecy over the site northwest of Las Vegas to cover up evidence of extra-terrestrials touching down on Earth.

Instead of encounters with flying saucers, the documents released by the Central Intelligence Agency on Thursday recount a less sensational history of Area 51 -- as a testing range for the government's U-2 spy plane during the Cold War.

The CIA in-house history makes no mention of the legendary "Roswell incident," when a weather balloon crashed in New Mexico in 1947. UFO true believers allege it was an alien spacecraft that went down, and that Area 51's hangars had hidden evidence of extra-terrestrial corpses.

But according to the CIA, the government secrecy surrounding Area 51 was not about Martians but about hiding a new spy plane from the Soviets.

The U-2 reconnaissance aircraft was designed to snoop on the Soviet Union at high-altitude, and its development was top-secret.

In April 1955, the CIA chose a remote dry lakebed in the Nevada desert as a testing ground, which was designated on maps as Area 51.

Test flights for the U-2 aircraft were conducted at a much higher altitude than commercial airliners or other military planes.

In the 1950s, commercial planes flew at between 10,000 and 20,000 feet and warplanes such as B-47 reached altitudes of less than 40,000 feet.

The U-2 planes flew at above 60,000 feet, and reports of unidentified flying objects in the Nevada desert started to roll in, the report said.

"High altitude testing of the U-2 soon led to an unexpected side effect -- a tremendous increase in reports of unidentified flying objects (UFOs)," it said.

The reports of UFOs often came from pilots from commercial airliners in the early evening hours, with the U-2 plane's silver wings reflecting the rays of the sun.

The surveillance planes appeared to be "fiery objects" high in the sky, it said.

"At this time, no one believed manned flight was possible above 60,000 feet, so no one expected to see an object so high in the sky," it said.

The commercial pilots and other observers on the ground wrote letters to an Air Force unit in Dayton, Ohio charged with investigating such sightings.

Anxious to avoid exposing the ultra-secret U-2 program, Air Force officers explained the sightings as merely due to natural phenomena, though they knew the high-flying U-2 was the true cause.

U-2 and other surveillance flights "accounted for more than one-half of all UFO reports during the late 1950s and most of the 1960s," it said.

The 400-page report, titled "Central Intelligence Agency and Overhead reconnaissance: The U-2 and Oxcart Programs, 1954-1974," was released as a result of a Freedom of Information request dating to 2005 from the National Security Archives at George Washington University.

The study was published in classified form for spy agencies in 1992 and a heavily censored version was published in 1998.

Area 51's location has been an open secret for years but government documents released previously had not acknowledged its existence and role in such a detailed way. Officials also had referred to a location "near Groom Lake."

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