Aug 8, 2014

How we form habits, change existing ones

Much of our daily lives are taken up by habits that we've formed over our lifetime. An important characteristic of a habit is that it's automatic-- we don't always recognize habits in our own behavior. Studies show that about 40 percent of people's daily activities are performed each day in almost the same situations. Habits emerge through associative learning. "We find patterns of behavior that allow us to reach goals. We repeat what works, and when actions are repeated in a stable context, we form associations between cues and response," Wendy Wood explains in her session at the American Psychological Association's 122nd Annual Convention.

What are habits?

Wood calls attention to the neurology of habits, and how they have a recognizable neural signature. When you are learning a response you engage your associative basal ganglia, which involves the prefrontal cortex and supports working memory so you can make decisions. As you repeat the behavior in the same context, the information is reorganized in your brain. It shifts to the sensory motor loop that supports representations of cue response associations, and no longer retains information on the goal or outcome. This shift from goal directed to context cue response helps to explain why our habits are rigid behaviors.

There is a dual mind at play, Wood explains. When our intentional mind is engaged, we act in ways that meet an outcome we desire and typically we're aware of our intentions. Intentions can change quickly because we can make conscious decisions about what we want to do in the future that may be different from the past. However, when the habitual mind is engaged, our habits function largely outside of awareness. We can't easily articulate how we do our habits or why we do them, and they change slowly through repeated experience. "Our minds don't always integrate in the best way possible. Even when you know the right answer, you can't make yourself change the habitual behavior," Wood says.

Participants in a study were asked to taste popcorn, and as expected, fresh popcorn was preferable to stale. But when participants were given popcorn in a movie theater, people who have a habit of eating popcorn at the movies ate just as much stale popcorn as participants in the fresh popcorn group. "The thoughtful intentional mind is easily derailed and people tend to fall back on habitual behaviors. Forty percent of the time we're not thinking about what we're doing," Wood interjects. "Habits allow us to focus on other things…Willpower is a limited resource, and when it runs out you fall back on habits."

How can we change our habits?

Public service announcements, educational programs, community workshops, and weight-loss programs are all geared toward improving your day-to-day habits. But are they really effective? These standard interventions are very successful at increasing motivation and desire. You will almost always leave feeling like you can change and that you want to change. The programs give you knowledge and goal-setting strategies for implementation, but these programs only address the intentional mind.

In a study on the "Take 5" program, 35 percent of people polled came away believing they should eat 5 fruits and vegetables a day. Looking at that result, it appears that the national program was effective at teaching people that it's important to have 5 servings of fruits and vegetables every day. But the data changes when you ask what people are actually eating. Only 11 percent of people reported that they met this goal. The program changed people's intentions, but it did not overrule habitual behavior.

According to Wood, there are three main principles to consider when effectively changing habitual behavior. First, you must derail existing habits and create a window of opportunity to act on new intentions. Someone who moves to a new city or changes jobs has the perfect scenario to disrupt old cues and create new habits. When the cues for existing habits are removed, it's easier to form a new behavior. If you can't alter your entire environment by switching cities-- make small changes. For instance, if weight-loss or healthy eating is your goal, try moving unhealthy foods to a top shelf out of reach, or to the back of the freezer instead of in front.

Read more at Science Daily

Many Sharks Much Older Than Previously Thought

Nuclear bomb testing during the 1950s and 60s is helping scientists to determine that many sharks today are much older than previously thought.

Earlier this year it was announced that some great white sharks swimming in the ocean now are 70 years old or more. A new study, published in the journal Marine & Freshwater Research, has found that many sand tiger sharks and likely other shark species too are much older than scientists had suspected.

“Validated lifespan for C. taurus (sand tiger shark) individuals in the present study reached at least 40 years for females and 34 years for males,” according to lead author Michelle Passerotti and colleagues.

They added “that ages of large adult sharks were underestimated by 11–12 years,” prior to the study.

Passerotti, a researcher at the National Marine Fisheries Service of the Southeast Fisheries Science Center, and her team came to that conclusion after analyzing sand tiger shark vertebrae from different life stages. The sharks hailed from waters off of the southeastern United States and South Africa.

Here’s where the bomb fallout comes in: Detonation of nuclear bombs during tests in the 50s and 60s produced “artificial” radiocarbon in the atmosphere. This is known as the bomb effect. The global carbon exchange cycle has thankfully been reducing the nuclear bomb-released radiocarbon, such that levels of bomb carbon were 100 percent above normal between 1963 and 1965, but about 20 percent above normal (i.e., pre-nuclear bomb testing) in the 1990s.

The radiocarbon pulse in the environment therefore created, and continues to create, time stamps, so scientists can measure radiocarbon levels in something (in this case, the shark vertebrae) and pair those measurements with a reference chronology.

The technique has been used to better date trees, but in more recent years, it’s been applied to sharks, which can be notoriously difficult to study. That’s because many sharks have large ocean ranges, swim in deep water, grow up discreetly in “nurseries,” and can be hard to tag-release-recapture.

The researchers suspect that sandbar sharks may be much older than presently thought as well.

The good news is that some sharks appear to enjoy impressive longevity. If you see a large great white in the ocean, for example, that shark could be a healthy senior citizen by human standards.

Read more at Discovery News

All Hail King Richard! Details of Elaborate Burial Unveiled

After years of heated controversy over the rightful resting spot for King Richard III, officials have finally decided on the reinterment details for the remains of the 15th-century English ruler.

His remains will be laid to rest on Thursday, March 26, 2015, in Leicester Cathedral during one of three services to honor the English king, the University of Leicester announced yesterday (Aug. 7).

The king's remains, which were discovered beneath a city council parking lot in Leicester, England, in 2012, will be tucked away in a tomb made of Swaledale fossil stone crafted by Michael Ibsen, a descendant of King Richard III's sister Anne of York. That design was unveiled on June 16.

A judicial review concluded on May 23 that the University of Leicester had the legal right to reinter Richard III's remains, after controversy erupted by Richard enthusiasts, including the Plantagenet Alliance, who claimed the king should be reburied in York, England, where he spent a good chunk of his life.

King Richard ruled England from 1483 to 1485, when he died at the Battle of Bosworth, the final battle in the War of the Roses, the civil war between the Houses of York and Lancaster. The king's body was buried in a hastily dug grave three days later, according to historical records and research published last May in the journal Antiquity. Once the remains were discovered, they underwent extensive study that included a look at the skeleton's physical characteristics and its DNA. After confirming the identity of the bones, researchers and others involved began to discuss the reburial.

"Our cathedral has been consistently committed to providing a fitting, dignified and memorable ceremony for the reinterment of King Richard," Rt. Rev. Tim Stevens, Bishop of Leicester, said in a statement. "We can now see how this works out in detail, and our city and county look forward to all the events of next spring."

The reburial will include much fanfare. On March 22, the university will place the king's remains into a lead-lined coffin, which will then be transferred from Leicester to Bosworth, as the villages linked in some way to Richard III's last days before his death in 1485 will be honored. The coffin will return to Leicester that evening, arriving at the Leicester Cathedral, where they'll be handed over to the church during a service.

King Richard III's remains will lie in repose for three days, during which time the public can pay their respects. The first service, on March 26, will be followed by similar events on March 27 and 28.

This week, contractor Fairhurst Ward Abbotts has begun to make space for the king's tomb.

Read more at Discovery News

This Goofy Fish Poops Out White-Sand Beaches

The parrotfish may or may not feed exclusively on algae. Probably does though.
Ah, Hawaii. The resplendent luaus and awe-inspiring volcanoes. Tom Selleck and his mustache running around private-investigating stuff. The beautiful white-sand beaches made of fish poop.

Oh, that’s right. Your precious Hawaiian beach vacation was actually a frolic through epic amounts of doody. Specifically, the doody from a very special kind of critter: the parrotfish. You see, parrotfish are quite partial to the algae that grow on coral, and they gnaw it off with two impressive rows of fused, beak-like teeth (hence their name). Simply by chewing on reefs, a large Hawaiian parrotfish can ingest a coral’s calcium carbonate and poop out up to 800 pounds of sand each year, according to marine biologist Ling Ong of Hawaii’s SWCA Environmental Consultants. One Australian species, she notes, produces up to one ton per year.

And the parrotfish isn’t alone here. “In places like Hawaii, where we have very little terrestrial input of sand, almost all of our sand is of biological origin,” Ong said. “So I like to tell people that the sand you’re standing on in Hawaii has probably gone through the gut of something. It’ll have gone through the gut of a parrotfish, a sea urchin, some kind of worm.”

Parrotfish come in staggeringly beautiful colors, unless you’re color blind. In which case, you’ll have to just take my word for it.
Parrotfish, though, serve a far more important purpose in their grazing. Algae is a major threat to corals, positively smothering them and stealing their precious light. Parrotfish play a huge role in keeping algae in check, though they can get a bit carried away. Some species have evolved to not only skim the algae off the top, but gnaw a few millimeters down to reach algae that has penetrated the coral. Overall, though, they’re the reef’s benevolent and indispensable gardeners.

Now, if you’re anything like me, you considered eating chalk at some point in your childhood. Luckily I never did—which isn’t to say I didn’t come close—because blackboard chalk used to be made of calcium carbonate, exactly what coral is made of. And when calcium carbonate mixes with acid, it fizzes like crazy. “It creates carbon dioxide,” said Ong. “So if you’re a regular animal and you had acid in your stomach and you ate a chunk of chalk, you would get fizzy quickly. It would be generating a lot of gas.”

So why aren’t parrotfish spontaneously exploding all over the reef? Well, they don’t have stomachs. They simply gnaw off the algae and calcium carbonate and grind it up with teeth at the back of their throat known as pharyngeal jaws (the same jaws, by the way, that the moray eel has evolved into horrifying forward-thrusting chompers like those in the queen from Alien). Their digestive systems then take up the nutritious algae while firing out the calcium carbonate as sand.

Mucus Sleeping Bags and Polychromatic Sex Changes

All of this beach-building is exhausting work, and indeed the parrotfish is a strangely heavy sleeper. Like, dangerously heavy. “They don’t wake up easily at all, which makes them fairly easy to catch,” said Ong, “because you can go down and shine a light at them and they’ll be sound asleep. And the ones you do catch, you put them in a dark bag and they go back to sleep.”

Ong isn’t sure why exactly they need such deep sleep, though it wouldn’t seem to make much evolutionary sense. Why leave yourself so vulnerable?

Well, younger, smaller parrotfish, which are of course more susceptible to predation, have a brilliant little trick. They tuck themselves into a crevice or under a ledge and secrete mucus to build a translucent, semi-solid sleeping bag, which balloons to encase the parrotfish in a water-filled bubble. It’s likely a measure to mask their scent from predators, or a kind of proximity sensor to detect when something is closing in. And when they wake up in the morning, they’ll recycle the cocoon by eating it for breakfast. Try doing that with your sleeping bag the next time you go camping.

A parrotfish demonstrates the world’s most ineffective force field.
But their heavy sleep makes the larger individuals extremely vulnerable to spearfishers, who target the easy prey at night. And while losing an individual parrotfish every once in a while to fishing may not seem like a huge deal, the way parrotfish societies are set up makes this kind of hunting a serious threat.

You see, most parrotfish species are sex-changers. Individuals are born female and form into schools. Once they’ve matured, the largest female will change into a male, assuming rule over the school, which essentially becomes his harem. He begins managing territory, chasing away rival males, and transforms his drab skin into the gaudy colors in the photos above.

Yet this color shift doesn’t happen every time. Some males eschew the lovely new outfit in favor of a more sneaky strategy: They pretend to still be female. “So when it comes to spawning, they can sneak in,” said Ong. “When the males and females spawn—either in the territory, or some of them actually congregate in a place and they group-spawn—the sneaker males can insert themselves in there. And there are a fair number, so it’s a reproductive strategy that must work.” (The giant Australian cuttlefish actually does the same, with males manipulating their arms to look like females, sneaking under dominant males to steal a kiss with their mates, and by steal a kiss I mean hand her bundles of sperm.)

If you’re going to sleep like a rock, you may as well look like one too.
Now, it’s great being the big man on campus—until a bigger bully shows up. “This is a fish that a lot of Pacific Islanders like to eat,” said Ong. “And normally they target the biggest fish, and that causes a problem for these kinds of sex changes, because you’re taking a lot of the males out of the population. And you’re also taking a lot of the big females out of the population, and they’re the ones that are creating the most young.”

Indeed, the creatures are overfished in most parts of the world, setting off a domino effect that leaves coral, already struggling to survive climate change, at the mercy of algae. And interestingly, according to Ong, parrotfish seem to be getting smaller. Could we be artificially selecting against the largest individuals by removing them from the gene pool? After all, we seem to have done the same with elephant tusks, poaching individuals with the most ivory and keeping them from passing along their genes for such size.

Read more at Wired Science

Aug 7, 2014

Shark Eyes Designed to Catch Photons in Twilight Zone

The unique eye structure of deep-sea bioluminescent sharks helps them survive in the twilight zone, a study has found.

Detailed mapping of the eye structure of five species of bioluminescent sharks reveals they have a higher rod densities than other sharks, report a team of international researchers in the journal PLOS ONE.

The twilight -- or mesopelagic -- zone covers ocean depths from 200 to 1000 meters down. Only the shorter wavelengths of light at the blue end of the spectrum reach this far down.

Mesopelagic sharks make up 12 per cent of all sharks and use bioluminescent light to communicate, find prey, and provide camouflage from predators.

Some species of lantern sharks are only 50 centimeters long.

"These amazing little animals aren't well understood, so by studying their eyes we can gain useful insights into how these sharks make a living," says study co-author, Professor Julian Partridge of the University of Western Australia.

Partridge and colleagues examined the eye shape, structure, and retinal cell pattern of four lantern shark species -- Etmopterus lucifer, E. splendidus, E. spinax and Trigonognathus kabeyai -- and one dalatiid or kitefin shark species -- Squaliolus aliae.

The authors found the eyes of bioluminescent sharks are designed to capture as much light as possible.

"We found things which hadn't been seen before in sharks, such as a layer of tissue behind the retina to reflect and increase the light available to photoreceptors," says Partridge.

The authors also found gaps between the lens and iris of these sharks, allowing extra light to reach the retina.

The sharks also had long thin photoreceptors, the rods in the back of their eyes which absorb light.

Previous studies have shown that long rods are very sensitive to light, while thin rods detect fast movement.

Sharp vision

Bioluminescence often appears as just a brief flash. The ability of these sharks to see details in the shape of that flash tells them if it's being produced by a potential mate, lunch or a predator.

Partridge and colleagues found the density and distribution of the ganglion cells, which send information from the photoreceptors to the brain, indicates these sharks have relatively good resolution.

"They can see fairly fine detail for a fish, although it's not as good as humans," says Partridge.

"We also found differences in the density patterns of the rods and ganglion cells, depending on whether these sharks lived in mid water, or near the sea floor."

The difference in density patterns indicates whether the sharks seek food directly in front of them or on the sea-bed below.

Bioluminescent camouflage

Partridge and colleagues also found a strange translucent structure in the top of the eye which they believe is used by bioluminescent sharks to balance their own light emissions for camouflage, against the light coming down from above.

"If you're an animal in the sea where there's still some down-welling light, you can look upwards for silhouettes that might then become your lunch," says Partridge.

"So there's a lot of selective pressure for animals to disguise their silhouette because there's nothing to hide behind in the deep sea. One way to deal with that is by disguising their shape by putting lights on their bellies."

Read more at Discovery News

Stone Age Skull May Contain Bits of Brain Matter

A Stone Age skull with what may be bits of brain clinging to it has been unearthed at an ancient hunter-gatherer site in Norway.

The skeletal fragment, which is about 8,000 years old, may have once belonged to an infant or a small child, though it is so packed into the soil that researchers still haven't been able to remove most of it, said Gaute Reitan, an archaeologist at the Museum of Cultural History in Oslo, Norway, who is excavating the site in conjunction with the University of Oslo.

The piece of skull was unearthed along with an adult's skeleton. These bones may represent one of the oldest Stone Age skeletons, and skulls, ever unearthed in Scandinavia, Reitan said.

While doing archaeological exploration last year prior to construction of a convention center in southwestern Oslo, local archaeologists found signs of an ancient settlement and passed the information along to Reitan and his colleagues, who did additional excavation.

Several pits contained microblades, or tiny pieces of flint that would have fit into slots in bone or wooden arrows, as well as stone axes and pieces of rock crystal — a smooth, clear glass that Mesolithic people placed in their arrowheads, Reitan said.

These pieces shaped by the Mesolithic people "look like the cleanest glass from a bottle of Coke," Reitan said.

Other pits revealed hearths with burnt bones, as well as postholes that would have supported the wooden beams of a simple hut.

The finds suggest that the site was once a semipermanent hunter-gatherer settlement.

Though the ancient humans may have eaten deer and elk, they likely survived mostly on the water's bounty, guiding their log boats or canoes through the Oslo fjord to hunt for marine mammals and fish, Reitan said. "They were first and foremost fisherman," he added.

In late June while excavating the same site, the team uncovered a man-size pit, roughly the shape of a bathtub, with the sides lined with stones. The pit was so tightly packed with sandy soil that it felt like concrete, Reitan said.

The burial contained one mostly intact skeleton, possibly from an adult male.

In that same pit, the team also found a fragment of what looked like the back of a child's skull, with bits of spongy, claylike "gray matter," clinging to it, Reitan said. Though it's still too early to say for sure, Reitan told Live Science he "can't think of anything else [it could be] but brain matter."

The burial also contained what look like deer antlers. Throughout the world, hunter-gatherers have placed deer antlers in the burials of loved ones, though the exact reason why has remained a mystery, Reitan said.

The discovery of the skeleton and skull may be among the oldest Stone Age skeletons in Scandinavia. The details of the burial — such as the wide, deeply dug pit and the potential deer antlers placed in the grave — resemble those of other Mesolithic sites from the region, he said.

"They shared much of the same religious beliefs and shared the same way of handling their dead," Reitan said. The concern and effort taken to dig a pit and leave goods for the deceased show the hints of ancient religious beliefs of Mesolithic people, he added.

Still, there is much more to learn about these long-gone hunter-gatherers. Though the archaeologists tentatively identified some of the artifacts buried in the pit, most of the bones are still embedded in clumps of soil. The team now must painstakingly brush and remove the tightly packed soil from around the bones to more thoroughly catalog the pit's contents, Reitan said.

Read more at Discovery News

Stellar Nursery Formed 30 Million Years Before Our Sun

The stellar nursery that produced our solar system separated out from the rest of the galaxy some 30 million years before the sun was born, new research shows.

“Considering that it took less than 100 million years for the terrestrial planets to form, this incubation time seems astonishingly long,” chemist and planetary scientist Martin Bizzarro, with the University of Copenhagen Natural History Museum in Denmark, writes in an article in this week’s Science.

The study reconciles a long-standing discrepancy between the abundances of two radioactive isotopes -- iodine-129 and hafnium-182 -- at the time of the sun’s birth some 4.567 billion years ago. The samples came from meteorites and were previously analyzed in laboratories.

“We did not measure these nuclei in meteorites, but explained the data already available,” lead researcher Maria Lugaro with Monash University in Australia, wrote in an email to Discovery News.

“The new research “delivers the first successful interpretation of meteoritic data that were presented beforehand but were difficult to explain,” she added.

Lugaro and colleagues calculated that the last time elements such as lead were added into the solar system’s birthing materials was no more than 30 million years before formation of the sun.

“This timing is significant because it represents the maximum time that the solar system matter was isolated from the rest of the galaxy -- and hence could not experience any more addition -- inside a stellar nursery before the formation of the sun,” Lugaro said.

Not only was the sun’s birthplace old, it also was likely very crowded, a finding that has implications for understanding how other star systems evolve, including those that host potentially habitable planets.

“The planets in the solar system survived dynamical interaction with the sun's siblings. At the moment, we cannot exclude that the sun's nursery may have been a very massive, long-living region where thousands or even tens of thousands of stars were born together. In this case, we would have the proof that extrasolar planetary systems can form and survive in crowded conditions,” Lugaro said.

Read more at Discovery News

Alien Life 'Inevitable' and We Could Detect It Within 20 Years

As astronomical instrumentation becomes more sophisticated, we are rapidly approaching a crossroads in the search for extraterrestrial life, according to a leading planetary scientist. It’s also “inevitable” that alien life exists in the universe given the preponderance of extrasolar planets that are being discovered — it’s up to us to seek out the extraterrestrial biosignatures.

These conclusions are outlined by Sara Seager, Professor of Planetary Science and Physics at the Massachusetts Institute of Technology (MIT), in a paper published in the journal Proceedings of the National Academy of Sciences on Aug. 4.

“In the coming decade or two, we will have a lucky handful of potentially habitable exoplanets with atmospheres that can be observed in detail with the next generation of sophisticated space telescopes,” writes Seager, pointing out that NASA’s James Webb Space Telescope (JWST) and a planned direct-imaging space telescope will be able to seek out biosignatures (i.e. chemicals created by extraterrestrial biology) in the atmospheres of nearby exoplanets. The JWST is set for launch in 2018.

“Life can be inferred by the presence of atmospheric biosignature gases — gases produced by life that can accumulate to detectable levels in an exoplanet atmosphere,” she writes.

To date, a handful of exoplanetary atmospheres have been studied through the analysis of their host star’s light passing through their atmospheres. As an alien world orbits its star, from our perspective, it may block some of the starlight from view and be registered as a “transit.” The transit method is used by NASA’s Kepler space telescope and has so far confirmed the detection of hundreds of exoplanets. But this method can also help us analyze the chemicals contained in exoplanetary atmospheres.

During a transit, if that exoplanet has an atmosphere, some of the starlight is filtered through its atmosphere. Some wavelengths of that light are absorbed by specific chemicals, leaving a spectroscopic ‘fingerprint’ in the starlight we detect. Although only the largest class of exoplanets have so far had their atmospheres analyzed in this way (gas giants with tight orbits around their stars known as “hot-Jupiters”), Seager argues that with the advent of advanced space telescopes, the composition of smaller worlds’ atmospheres could also studied. Habitable “super-Earths” fall into this category.

Once this happens, we can begin to observe small rocky worlds, potentially detecting spectroscopic signatures of chemicals associated with life.

Although the next generation of space telescopes may be able to detect biosignatures in nearby exoplanets, Seager urges caution.

“(M)any different gases are produced by life, but the anticipated diversity of exoplanet atmosphere composition and host star environments may yield different detectable biosignature gases than the terrestrial examples. Even with excellent data, false positives will drive a permanent ambiguity in many cases,” she adds.

Molecules such as methane can be generated through biological (methanogenic) and geological (volcanic) processes, so the detection of methane in an exoplanetary atmosphere may not indicate life. To find out what is generating that gas, astronomers will need to study the atmosphere in its entirety to avoid jumping to conclusions about that world’s biological potential. The identification of these “false positives,” using advanced instrumentation, will be critical when seeking out genuine biosignatures.

The advances in space-based observatories are tantalizing and, with the launch of JWST and other advanced direct imaging telescopes (such as the “star shade” concept), we could start studying small habitable worlds with atmospheres and teasing hints as to any biosignatures within the next couple of decades.

But to fully investigate this exciting class of exoplanet, “we require the ability to directly image exoplanets orbiting 1,000 or more of the nearest sun-like stars.” Such an endeavor would require a huge space-borne observatory — an optical telescope with a diameter exceeding 10 meters. Considering the Hubble Space Telescope is only 2.4 meters in diameter, the exoplanetary atmosphere telescopes of the future will require some huge innovative leaps before they become a reality.

One thing seems certain, however. The longer we gaze into the stars, the more certain we become about the possibility for life beyond Earth.

Read more at Discovery News

Aug 6, 2014

Jellyfish Uses Supercomputing Strategy to Find Food

The barrel jellyfish, isn't just the largest jelly found in the waters around the United Kingdom, it's also one of the animal kingdom's most strategic searchers, according to a new study.

To locate the best possible meal in the vast waters of its marine habitat, the barrel jellyfish (Rhizostoma octopus) uses a strategy most commonly associated with the world's fastest supercomputers — an approach known as fast simulated annealing.

For mathematicians, fast simulated annealing is an algorithm, implemented by a supercomputer, which can find optimal solutions to complex problems in a relatively short amount of time. For jellyfish, fast simulated annealing is a highly evolved search strategy categorized by a series of predictable movements that bring the jelly closer and closer to large numbers of plankton, its preferred prey.

This complex search strategy has never been observed before in nature, according to study lead author Andy Reynolds, a scientist at Rothamsted Research, an agricultural research center in the U.K.

Yet, other mathematical patterns of movement have been widely observed in the natural world, Reynolds said. The most common of these patterns, the "Lévy walk," is a less complex version of the barrel jelly's approach.

"A Lévy walk is random walk in which frequently occurring small steps are interspersed with more rarely occurring longer steps, which in turn are interspersed with even rarer, even longer steps and so on," Reynolds told Live Science in an email. (The Lévy walk was named after French mathematician Paul Lévy, who was noted for his work in the theory of probability.)

While this may sound like a fairly complex way of searching for something, Reynolds said it's similar to the way you might search for your lost car keys in the living room sofa and then, not finding them there, head over to the closet to check your coat pocket.

"This hierarchical nested pattern is highly effective when searching because once an area has been intensively surveyed, the searcher is relocated to another area and then begins a new bout of intensive searching," Reynolds said.

Some of the species that have been observed using Lévy walks to locate their meals include sharks, penguins, honeybees, ants, turtles and even human hunter-gatherers.

But among these many species, the barrel jelly stands out because, in addition to exhibiting this Lévy walk pattern, it also engages several search methods that others species don't seem to use.

One of the barrel jelly's search-optimizing behaviors, often referred to as a "bounce," occurs when the jellyfish starts out in one depth of water and then makes a long glide either upwards or downwards to a different depth of water. If it doesn't find a meal in the new location, the jellyfish will "bounce" again to return to its original position.

Some scientists believe that the jelly's tendency to bounce around in the water may actually hinder its ability to search for food, but according to Reynolds, these unusual animals have had it right all along.

The jellyfish, which will sometimes repeat its pattern of bounces dozens of times a day, uses this strategy to slowly home in on the highest concentrations of plankton, Reynolds explained.

The behavior therefore makes the barrel jelly even more efficient than other marine animals, such as penguins and sharks, that only use Lévy walks to search for prey, Reynolds said.

If the barrel jelly's unusual way of searching for food really is the best way to do it, then why aren't other marine species using the same strategy?

The answer has to do with diet, Reynolds said. The barrel jellyfish benefits from spending long periods of time searching for concentrations of prey because it needs to eat a lot of plankton before it is satisfied, Reynolds said. This is different from sharks and penguins, which Reynolds said can survive by eating the occasional fish.

"A Lévy search is highly effective in finding the next meal, when any meal will do. Fast simulated annealing, on the other hand, takes the forager to the best possible meal," Reynolds said. "This is what makes jellyfish special — they are very discerning diners, unlike bony fish, penguins, turtles and sharks, which are just looking for any meal."

This high level of discernment is also what draws certain mathematicians and engineers to the strategy of fast simulated annealing for supercomputing, Reynolds said.

Read more at Discovery News

First Venezuelan Dino Was a Social Creature

The first dinosaur found in Venezuela is one of the world's oldest, living right after the major extinction event at the end of the Triassic Period.

The 200-million-year-old dinosaur, described in the latest issue of the Proceedings of the Royal Society B, has been named Laquintasaura venezuelae. The name was inspired by where it was discovered, the La Quinta Formation in Tachira State, Venezuela.

"Laquintasaura was a small bipedal dinosaur about 1 meter (3.3 feet) long," lead author Paul Barrett, a paleontologist at the Natural History Museum in London, told Discovery News. "It was probably largely herbivorous, but its slightly curved and elongated teeth hint at occasional omnivory. The teeth are the most distinctive feature of the new dinosaur, as their elongated, curved outline and striated surfaces are unique."

"There are many surprising firsts with Laquintasaura," Barrett said. "Not only does it expand the distribution of early dinosaurs, its age makes it important for understanding their early evolution and behavior."

Another important first for this dinosaur is that it provides the earliest likely evidence for social behavior in "bird-hipped" dinosaurs (ornithischians). The group includes species such as stegosaurus, triceratops and iguanodon.

Fossils from at least four Laquintasaura individuals were found together, with the dinosaurs ranging in age from 3 to approximately 12 years old. The researchers suspect that the dinosaurs were "gregarious" and lived together in a herd. It looks like they died together too, although the cause of their death remains a mystery.

Laquintasaura's later Cretaceous relatives were social animals, so it's theorized this characteristic emerged early among bird-hipped dinosaurs.

"It is fascinating and unexpected to see they lived in herds, something we have little evidence of so far in dinosaurs from this time," Barrett said.

So why did it take so long to find a dinosaur in Venezuela? Researchers thought the region around 200 million years ago would have been too inhospitable to support a dino, or for that matter any relatively large animal.

Because Laquintasaura munched on ferns -- and probably insects and other small prey -- suggests that Venezuela supported a richer ecosystem than was previously thought.

Another unexpected aspect is that this new dinosaur emerged just 500,000 years ago -- a veritable drop in the geological time bucket -- after the Triassic-Jurassic extinction event that led to the disappearance of at least half of Earth's species at the time.

Read more at Discovery News

6,500-Year-Old 'Noah' Skeleton Found in Museum Closet

The University of Pennsylvania did have a skeleton in its closet -- and it was quite old.

Scientists at the Penn Museum (the University of Pennsylvania Museum of Archaeology and Anthropology) announced Tuesday they had found a 6,500-year-old skeleton in the museum basement.

The bones belonged to a once well-muscled, 5'9" man estimated to be at least 50 years old. His remains had been lying in a coffin-like box for 85 years with no identifying documents. Since he likely outlived a great flood that, millennia later would be a precursor to the Biblical story, some are referring to the skeleton as "Noah."

"This summer, a project to digitize old records from a world-famous excavation brought that documentation, and the history of the skeleton, back to light," the Penn Museum said in a statement.

Records revealed the complete skeleton was unearthed at the site of Ur, an ancient city near modern-day Nasiriyah in southern Iraq, in 1929–30.

At that time, a joint Penn Museum/British Museum excavation team led by Sir Leonard Woolley excavated 48 graves in a floodplain, all dating to the Ubaid period. This was a culture characterized by large village settlements that originated on the alluvial plains of southern Mesopotamia around 5500 B.C. and lasted until roughly 4000 B.C.

Of all the bones found, only one skeleton was in good enough condition to recover. Buried with arms at his sides and hands over his abdomen, with pottery vessels at the feet, the skeleton is 2,000 years older than the famous Mesopotamian "royal tombs" that Woolley found in the same Ur location.

After Woolley discovered the Royal Cemetery, he kept digging. Around 40 feet down, he reached a layer of clean, water-lain silt. Digging further, Woolley found graves cut into the silt and eventually another silt layer. This "flood layer" was more than 10 feet deep.

Reaching below sea level, Woolley concluded that Ur had originally been a small island in a surrounding marsh. Then a great flood washed away the land.

The burial that produced the Penn museum skeleton was one of those cut into the deep silt. This indicates the man, as well as other people in Ur, had lived after the flood.

Archaeologists believe the disaster likely inspired stories of an epic flood which are the historic precursors of the biblical story written millennia later.

As such, Penn researchers named the rediscovered skeleton "Noah."

Though, since the skeleton is much older than the Bible, "Utnapishtim" would have been more appropriate.

"He was named in the Gilgamesh epic as the man who survived the great flood," William Hafford, Ur Digitization Project Manager at Penn.

Hafford was able to reconstruct how the skeleton reached the museum. Woolley himself painstakingly removed the intact skeleton, covered it in wax, fastened it onto a piece of wood, and lifted it out with the surrounding dirt using a burlap sling.

Read more at Discovery News

Fantastically Wrong: Why the Guy Who Discovered Uranus Thought There’s Life on the Sun

You can’t live on the sun. Well, you can try if you want. I’m not your mother.
There are a whole lot of places in the universe that aren’t exactly conducive to the proliferation of life: the vacuum of space, for instance, or the poisonous, boiling atmosphere of Venus, or anywhere Chuck Norris goes. But surely the most brutal are the unimaginably hot surfaces of stars like our sun, furnaces so powerful that they fling energy billions of miles.

Sure, we know that now. But in 1795, prominent astronomer William Herschel, who had discovered Uranus 14 years previous, took the opposite view. In the essay “On the Nature and Construction of the Sun and Fixed Stars,” he argued that the sun is simply an enormous planet, and because all other planets in our solar system contain life (a popular opinion in his day), so too must our star. It sounds mad, but he put forth sophisticated arguments to bolster his theory.

But first, a bit of background on the years leading up to Herschel’s bold claim. The telescope was invented in the early 1600s, and was first turned skyward not by its inventors, who were concerned with more terrestrial applications (“seeing faraway things as though nearby,” as one patent application read), but by Galileo. Observations of the sun began almost immediately, and what followed was a sort of stargazing gold rush, as inventors developed ever more powerful devices, while of course remaining cautious not to burn their eyeballs out of their heads.

William Herschel, the discoverer of Uranus, believer of life on the sun, disapprover of paragraphs above and to the left of his person.
By the 1700s, astronomers observing sunspots hit upon an idea: The sun was a regular old terrestrial planet like ours that just happened to be covered with a luminous atmosphere. One Englishman figured that such sunspots were volcanoes belching smoke through glowing gas, while another reckoned they were towering mountains peeking through, according to Steven Kawaler and J. Veverka in their essay “The Habitable Sun: One of William Herschel’s Stranger Ideas.” Another figured the bright, hot matter wasn’t an atmosphere but an ocean, and that sunspots were instead mountains exposed by ebbing tides.

In reality, sunspots are areas where the star’s magnetic field becomes highly concentrated, inhibiting convective motion and therefore the transport of heat, dropping the temperature inside to thousands of degrees cooler than the rest of the surface. It’s still quite bright (if you could pull one out of the sun it’d glow brighter than a full moon), but in contrast to the surrounding hotter areas it appears dark. And that apparent ebbing tide exposing and enveloping mountains? It’s actually the sun’s shifting magnetic field opening up and closing new spots willy-nilly.

Anyway, along comes Herschel, who subscribes to the idea that sunspots can be either openings in the atmosphere exposing land or mountains rising above the luminosity. Scaling up the potential size of mountains on the sun using a mountain on Earth with a height of 3 miles, he gets a potential height of 334 miles, adding that “there can be no doubt but that a mountain much higher would stand very firmly”—unlike his theory as a whole, appropriately enough.

Sunspots utilize the time-tested buddy system, opening up in pairs as the sun’s magnetic field comes out of one and dives back into another.
As to how the atmosphere formed in the first place, Herschel invokes the formation of clouds on Earth, “but with this difference, that the continual and very extensive decompositions of the elastic fluids of the sun, are of a phosphoric nature, and attended with lucid appearances, by giving out light.” But why hasn’t the sun exhausted its supply of “elastic fluids” that throw so much energy into space? Just as clouds rain water back down to Earth, “in decomposition of phosphoric fluids every other ingredient but light may also return to the body of the sun.” I mean, could you imagine it raining light? That’d just be silly.

According to Kawaler and Veverka in their essay, “it is clear that what especially attracted Herschel to this model of the sun were its philosophical implications,” since it brought the sun in league with other planetary bodies. “Clearly,” they add, “it is a product of Herschel’s prejudice that all planets are inhabited.”

It’s Getting Hot in Here, So Take Off All Your Preconceived Notions of Where Life Can Potentially Exist

It was prejudice that of course came with problems, both scientifically and existentially. While Herschel believed the sun to be inhabited “by beings whose organs are adapted to the peculiar circumstances of that vast globe,” at the same time he pointed out that “angry moralists” thought the star to be “a fit place for the punishment of the wicked,” while “fanciful poets” reckoned it was home to blessed spirits. Clearly not all parties could inhabit the same world without stepping on each other’s toes.

And then there was the question of how the luminous atmosphere wouldn’t simply cook any life on the sun. Herschel argued that “heat is produced by the sun’s rays only when they act upon a calorific medium.” Substances that can be heated, you see, contain the “matter of fire,” as a flint can ignite gunpowder that already contains such fire. If light alone could cause heat, he reasoned, then you’d expect the top of our highest mountains, where light’s course is the least interrupted, to be quite hot indeed, when in fact they’re frigid. And because the sun emits such an incredible amount of light, it stands to reason that little of it is acting upon such a “calorific medium” to produce heat on the surface. There must be something chemically different about the surface and atmosphere of the sun.

According to Kawaler and Veverka, six years after he proposed this theory, Herschel returned with another reasoning of how life on the sun would keep from bursting into flames. The sun must have not just a luminous atmosphere, but an underlying layer of clouds so opaque that they bounce the light into space, protecting the inhabitants below.

 The scientific community, however, wasn’t buying it. The polymath Thomas Young reckoned that not only would the cloud layer be totally worthless at reflecting heat, no matter how dense it was, but there also was the rather glaring problem of gravity. Living beings on such a large body would be flattened like Wile E. Coyote beneath an anvil—my words, not his. And in 1821, David Brewster, also a polymath (Europe was lousy with them back then), instead attacked the very core of Herschel’s reasoning: He’d based his theory on the assumption that the sun was like any other planet and would therefore harbor life, when the sun was in fact unique in our solar system.

And in 1801, the collapse of a building in Germany led humanity to see the sun in a totally new light. Joseph von Fraunhofer, an orphan and decidedly not a polymath, was trapped when the mirror and glass shop he apprenticed in crumbled. The crowd that gathered to witness the ensuing rescue included Prince Elector Maximilian Joseph IV, who took pity on von Fraunhofer, providing him cash and books to further his studies. Von Fraunhofer eventually made huge advances in lens-making and, more importantly for astronomy, invented the spectroscope, which was later used to determine the chemical makeup of the sun by analyzing its light.

What we then began to understand is that instead of featuring a surface for life to amble around upon, the sun is in fact comprised of hydrogen and helium gas. And later on in the early 20th century, scientists finally solved the mystery of the sun’s power: It is, as They Might Be Giants noted, a gigantic nuclear furnace. Specifically, it’s a nuclear fusion furnace, in which hydrogen atoms collide to produce not only helium, but astounding amounts of energy and sunburns on Earth.

Read more at Wired Science

Aug 5, 2014

Scientists change butterflies wing color in just six generations

Yale University scientists have chosen the most fleeting of mediums for their groundbreaking work on biomimicry: They've changed the color of butterfly wings.

In so doing, they produced the first structural color change in an animal by influencing evolution. The discovery may have implications for physicists and engineers trying to use evolutionary principles in the design of new materials and devices.

The research appears this week in the journal Proceedings of the National Academy of Sciences.

"What we did was to imagine a new target color for the wings of a butterfly, without any knowledge of whether this color was achievable, and selected for it gradually using populations of live butterflies," said Antónia Monteiro, a former professor of ecology and evolutionary biology at Yale, now at the National University of Singapore.

In this case, Monteiro and her team changed the wing color of the butterfly Bicyclus anynana from brown to violet. They needed only six generations of selection.

Little is known about how structural colors in nature evolved, although researchers have studied such mechanisms extensively in recent years. Most attempts at biomimicry involve finding a desirable outcome in nature and simply trying to copy it in the laboratory.

"Today, materials engineers are making complex materials to perform multiple functions. The parameter space for the design of such materials is huge, so it is not easy to search for the optimal design," said Hui Cao, chair of Yale's Department of Applied Physics, who also worked on the study. "This is why we can learn from nature, which has obtained the optimal solutions in many cases via natural evolution over millions of years."

Indeed, the scientists explained, natural selection algorithms can select for multiple characteristics simultaneously -- which is standard operating procedure in the natural world.

The desired color for the butterfly wings was achieved by changing the relative thickness of the wing scales -- specifically, those of the lower lamina. It took less than a year of selective breeding to produce the color change from brown to violet.

Read more at Science Daily

How spiders spin silk

Spider silk is an impressive material; lightweight and stretchy yet stronger than steel. But the challenge that spiders face to produce this substance is even more formidable. Silk proteins, called spidroins, must convert from a soluble form to solid fibers at ambient temperatures, with water as a solvent, and at high speed. How do spiders achieve this astounding feat? In new research publishing in the open access journal PLOS Biology on August 5, Anna Rising and Jan Johansson show how the silk formation process is regulated. The work was done at the Swedish University of Agricultural Sciences (SLU) and Karolinska Institutet in collaboration with colleagues in Latvia, China and USA.

Spidroins are big proteins of up to 3,500 amino acids that contain mostly repetitive sequences, but the most important bits for the conversion of spidroins into silk are the ends. These terminal regions of the proteins are unique to spider silk and are very similar between different spiders. Spidroins have a helical and unordered structure when stored as soluble proteins in silk glands, but when converted to silk their structure changes completely to one that confers a high degree of mechanical stability. These changes are triggered by an acidity (pH) gradient present between one end of the spider silk gland and the other. The gland proceeds from a narrow tail to a sac to a slender duct, and it is known that silk forms at a precise site within the duct. However, further details of spider silk production have been elusive.

By using highly selective microelectrodes to measure the pH within the glands, the authors showed the pH falls from a neutral pH of 7.6 to an acidic pH of 5.7 between the beginning of the tail and half-way down the duct, and that the pH gradient was much steeper than previously thought. The microelectrodes also showed that the concentration of bicarbonate ions and pressure of carbon dioxide simultaneously rise along the gland. Taken together, these patterns suggested that the pH gradient might form through the action of an enzyme called carbonic anhydrase, which converts carbon dioxide and water to bicarbonate and hydrogen ions (and thereby creating an acidic environment). Using a method developed by the authors, they were able to identify active carbonic anhydrase in the narrower part of the gland and confirm that carbonic anhydrase is indeed responsible for generating the pH gradient.

The authors also found that pH had opposite effects on the stability of the two regions at each end of the spidroin proteins, which was surprising given that these regions had been suggested to have similar roles in silk formation. While one of the ends (the "N-terminal domain") tended to pair up with other molecules at the beginning of the duct and became increasingly stable as the acidity increased along the duct, the other end (the "C-terminal domain") destabilized as the acidity increased, and gradually unfolded until it formed the structure characteristic of silk at the acidic pH of 5.5. These findings show that both ends of the protein undergo dramatic structural changes at the pH found at the beginning of the duct, which is also the point where carbonic anhydrase activity is concentrated.

Read more at Science Daily

Planet-like object may have spent its youth as hot as a star

Astronomers have discovered an extremely cool object that could have a particularly diverse history -- although it is now as cool as a planet, it may have spent much of its youth as hot as a star. The team publish their results in the journal Monthly Notices of the Royal Astronomical Society.

The current temperature of the object is 100-150 degrees Celsius, intermediate between that of Earth and Venus. But the object shows evidence of a possible ancient origin, implying that a large change in temperature has taken place. In the past this object would have been as hot as a star for many millions of years.

Called WISE J0304-2705, the object is a member of the recently established "Y dwarf" class -- the coolest stellar temperature class yet defined, added to the end of the sequence OBAFGKMLT (for historical reasons this is not in alphabetical order but follows a decline in temperature from O to T). Although its temperature is not far off that of our own world, the object is not like the rocky Earth-like planets and instead is a giant ball of gas like Jupiter.

The international discovery team, led by Prof David Pinfield at the University of Hertfordshire, identified the Y dwarf using the Wide-field Infrared Survey Explorer (WISE) observatory -- a NASA space telescope that since its launch in 2009 has imaged the entire sky in mid-infrared light (rather redder than the reddest light we can see with our eyes). The team also dispersed the light emitted by the Y dwarf into a spectrum, which allowed them to determine its current temperature and better understand its history.

Only 20 other Y dwarfs have been discovered to-date, and amongst these WISE J0304-2705 is defined as 'peculiar' due to unusual features in its emitted light spectrum. "Our measurements suggest that this Y dwarf may have a composition and/or age characteristic of one of the Galaxy's older members" explains Prof Pinfield. "This would mean its temperature evolution could have been rather extreme -- despite starting out at thousands of degrees this exotic object is now barely hot enough to boil a cup of tea."

The reason that WISE J0304-2705 underwent such extensive evolutionary cooling is because it is "sub-stellar" -- its interior never became hot enough for hydrogen fusion, the process that has kept the Sun hot for billions of years. And without an energy source maintaining a stable temperature, cooling and fading was inevitable.

If WISE J0304-2705 is an ancient object then its temperature evolution would have followed the stages shown in the illustration. During the first 20 million years or so of its life it would have had a temperature of at least 2800 degrees C, the same as red dwarf stars like Proxima Centauri (the nearest star to the Sun). After 100 million years it would have cooled to about 1500 degrees C, with silicate clouds condensing out in its atmosphere. At a billion years of age it would have cooled to about 1000 degrees C, cool enough for methane gas and water vapour to dominate its appearance. And since then it has continued to cool to its current temperature of 100 to 150 degrees C.

WISE J0304-2705 is as massive as 20 to 30 Jupiters combined, so somewhere between the least massive stars and typical planets. But in terms of temperature it may have actually "taken the journey" from star-like to planet-like conditions.

Having identified WISE 0304-2705, Prof Pinfield's team made crucial ground-based observations with some of the world's largest telescopes -- the 8m Gemini South Telescope, the 6.5m Magellan Telescope and the European Southern Observatory's 3.6m New Technology Telescope, all located in the Chilean Andes.

Team member Dr Mariusz Gromadzki said "The ground based measurements were very challenging, even with the largest telescopes. It was exciting when the results showed just how cool this object was, and that it was unusual."

"The discovery of WISE J0304-2705, with its peculiar light spectrum, poses ongoing challenges for the most powerful modern telescopes that are being used for its detailed study" remarked Prof Maria Teresa Ruiz, team member from the Universidad de Chile.

WISE J0304-2705 is located in the Fornax (Furnace) constellation in the southern hemisphere of the sky, belying its cool temperature and is between 33 and 55 light years away.

Read more at Science Daily

Extinct Penguin Was Tall Enough to Play in the NBA

A penguin that lived more than 35 million years ago was the largest ever, and would stand twice as tall as today's largest penguin, according to new fossil evidence.

Palaeeudyptes klekowskii would have stood about 6 feet 6 inches tall and weighed around 250 pounds, according to analysis of new bones found on Seymour Island in Antarctica by an Argentinian museum researcher.

The newly discovered bones -- a partial wing and an ankle-and-foot-bone structure called the tarsometatarsus -- gave Carolina Acosta Hospitaleche, from the La Plata Museum in Argentina, a way to derive the height of the long-lost penguin giant.

Today's largest penguin, the Emperor penguin, stands about 3 and a half feet tall, making it Spud Webb next to the Shaquille O'Neal that was P. klekowskii.

P. klekowskii lived during a goldilocks period for its kind -- "a wonderful time for penguins, when 10 to 14 species lived together along the Antarctic coast," Acosta Hospitaleche told New Scientist.

The new bones aren't the first ever found for P. klekowskii; Seymour Island contains no shortage of penguin fossils. But the new finds are the first to allow for such extrapolation of sheer, slam-dunking height.

From Discovery News

Roman Road Reveals Oldest Potholes

Potholes have been a nuisance to drivers as far back as the Roman Empire, a newly discovered Roman road has revealed.

Unearthed at Ipplepen, a site thought to be part of the largest Romano-British settlement in Devon outside of Exeter, U.K., the road featured wheel ruts similar to those found at Pompeii.

According to the archaeologists, the grooves were caused by horse-drawn carts being driven over the road over a long period of time.

“It’s intriguing to think what the horse-drawn carts may have been carrying and who was driving them. This is a fantastic opportunity to see a ‘snap shot’ of life 2000 years ago,” Danielle Wootton, the Devon Finds Liaison Officer for the Portable Antiquities Scheme, said.

Drivers at the time had to deal with hazardous road surfaces — archaeologists found evidence for some of the oldest-known potholes.

Holes were filled in with lots of tightly packed stones in order to make the surface smoother and easier for travlers.

“A smooth road surface meant that there was less chance of getting the wheels of your cart stuck,” Wootton said.

The signs of wear and maintenance on the road suggest that heavy traffic characterized the site at that time.

“For this reason, it was important to keep it in a good state of repair,” University of Exeter archaeologist Ioana Oltean told Discovery News.

Although archaeological evidence revealed the ancient Romans drove on the left in some parts of England, it wasn’t possible to tell if left-hand driving also ruled traffic at Ipplepen.

“Like their modern counterparts, Roman roads were made to accommodate traffic both ways,” Oltean said.

Read more at Discovery News

Aug 4, 2014

Flores bones show features of Down syndrome, not a new 'Hobbit' human

In October 2004, excavation of fragmentary skeletal remains from the island of Flores in Indonesia yielded what was called "the most important find in human evolution for 100 years." Its discoverers dubbed the find Homo floresiensis, a name suggesting a previously unknown species of human.

Now detailed reanalysis by an international team of researchers including Robert B. Eckhardt, professor of developmental genetics and evolution at Penn State, Maciej Henneberg, professor of anatomy and pathology at the University of Adelaide, and Kenneth Hsü, a Chinese geologist and paleoclimatologist, suggests that the single specimen on which the new designation depends, known as LB1, does not represent a new species. Instead, it is the skeleton of a developmentally abnormal human and, according to the researchers, contains important features most consistent with a diagnosis of Down syndrome.

"The skeletal sample from Liang Bua cave contains fragmentary remains of several individuals," Eckhardt said. "LB1 has the only skull and thighbones in the entire sample."

No substantial new bone discoveries have been made in the cave since the finding of LB1.

Initial descriptions of Homo floresiensis focused on LB1's unusual anatomical characteristics: a cranial volume reported as only 380 milliliters (23.2 cubic inches), suggesting a brain less than one third the size of an average modern human's and short thighbones, which were used to reconstruct a creature standing 1.06 meters (about 3.5 feet tall). Although LB1 lived only 15,000 years ago, comparisons were made to earlier hominins, including Homo erectus and Australopithecus. Other traits were characterized as unique and therefore indicative of a new species.

A thorough reexamination of the available evidence in the context of clinical studies, the researchers said, suggests a different explanation.

The researchers report their findings in two papers published today (Aug. 4) in the Proceedings of the National Academy of Sciences.

In the first place, they write, the original figures for cranial volume and stature are underestimates, "markedly lower than any later attempts to confirm them." Eckhardt, Henneberg, and other researchers have consistently found a cranial volume of about 430 milliliters (26.2 cubic inches).

"The difference is significant, and the revised figure falls in the range predicted for a modern human with Down syndrome from the same geographic region," Eckhardt said.

The original estimate of 3.5 feet for the creature's height was based on extrapolation combining the short thighbone with a formula derived from an African pygmy population. But humans with Down syndrome also have diagnostically short thighbones, Eckhardt said.

Though these and other features are unusual, he acknowledged, "unusual does not equal unique. The originally reported traits are not so rare as to have required the invention of a new hominin species."

Instead, the researchers build the case for an alternative diagnosis: that of Down syndrome, one of the most commonly occurring developmental disorders in modern humans.

"When we first saw these bones, several of us immediately spotted a developmental disturbance," said Eckhardt, "but we did not assign a specific diagnosis because the bones were so fragmentary. Over the years, several lines of evidence have converged on Down syndrome."

The first indicator is craniofacial asymmetry, a left-right mismatch of the skull that is characteristic of this and other disorders. Eckhardt and colleagues noted this asymmetry in LB1 as early as 2006, but it had not been reported by the excavating team and was later dismissed as a result of the skull's being long buried, he said.

A previously unpublished measurement of LB1's occipital-frontal circumference -- the circumference of the skull taken roughly above the tops of the ears -- allowed the researchers to compare LB1 to clinical data routinely collected on patients with developmental disorders. Here too, the brain size they estimate is within the range expected for an Australomelanesian human with Down syndrome.

LB1's short thighbones not only match the height reduction seen in Down syndrome, Eckhardt said, but when corrected statistically for normal growth, they would yield a stature of about 1.26 meters, or just over four feet, a figure matched by some humans now living on Flores and in surrounding regions.

Read more at Science Daily

How amphibians crossed continents: DNA helps piece together 300-million-year journey

There are more than 7,000 known species of amphibians that can be found in nearly every type of ecosystem on six continents. But there have been few attempts to understand exactly when and how frogs, toads, salamanders and caecilians have moved across the planet throughout time.

Armed with DNA sequence data, Alex Pyron, an assistant professor of biology at the George Washington University, sought to accurately piece together the 300-million-year storyline of their journey.

Dr. Pyron has succeeded in constructing a first-of-its-kind comprehensive diagram of the geographic distribution of amphibians, showing the movement of 3,309 species between 12 global ecoregions. The phylogeny -- or diagram of evolutionary relationships -- includes about half of all extant amphibian species from every taxonomic group.

"There have been smaller-scale studies, but they included only a few major lineages and were very broad," Dr. Pyron said. "What we needed was a large-scale phylogeny that included as many species as possible. That allows us to track back through time, not only how different species are related, but also how they moved from place to place."

His findings, which appear in the journal Systematic Biology, suggest that, contrary to popular belief, certain groups of amphibians may have swam long distances from one landmass to another within the past few million years.

Biologists have long hypothesized the distribution of extant lineages of amphibians has been driven by two major processes: vicariance and dispersal.

Vicariance occurs when a population is separated following a large-scale geophysical event. After the fragmentation of supercontinent Pangaea and the subsequent split of the Laurasian and Gondwanan landmasses, certain groups of amphibians were able to "hitch a ride" from one continent to another, Dr. Pyron explained. The researcher's biogeographic analysis supports this hypothesis, showing that continental movement can explain the majority of patterns in the distribution of extant species of amphibians.

Dr. Pyron also found that dispersal during the Cenozoic Era (66 million years ago to the present), likely across land bridges or short distances across oceans, also contributed to their distribution.

Given their ancient origin, it is unsurprising that the history of amphibians is a mixture of both vicariance and dispersal. But the third and final distribution pattern that Dr. Pyron notes in his study was an unexpected finding.

Past studies have assumed that long-distance over water dispersal was essentially impossible for amphibians due to salt intolerance. However, when Dr. Pyron began completing his analysis, he noticed a number of cases of distribution that could not be explained by old age.

For instance, one group of frogs found in Australia and New Guinea (pelodryadine hylids) that originated around 61 to 52 million years ago is deeply nested within a group of amphibians that exist only in South America. By the time pelodryadines originated, all major continental landmasses occupied their present-day positions, with South America and Australia long separated from Antarctica.

"They're 120 million years too late to have walked to Australia," Dr. Pyron said.

So how could this group of South American amphibians be related to frogs on the other side of the world?

"You wouldn't think that frogs would be able to swim all the way there, but that seems like one of the more likely explanations for how you could have such a young group nested within South America and have it somehow get to this other continent," Dr. Pyron said.

In his study, Dr. Pyron points two other instances of long-distance oceanic dispersal.

"What you have is this mixture of processes. You have vicariance, which over 300 million years has put certain groups in Africa, some in Australia and others in South America," Dr. Pyron said. "But even more recently, within the last few million years, you have these chance events of long distance dispersals across the ocean, which can influence distribution patterns."

Read more at Science Daily

Fluffy, Golden Bat From Bolivia ID'd as New Species

A newly identified species of bat from Bolivia isn’t exactly spooky. It features fluffy golden yellow fur and a cute pug nose.

Myotis midastactus had been seen before, but was classified as another bat found in the Amazon in South America called Myotis simus. Once Dr. Ricardo Moratelli from the Oswaldo Cruz Foundation in Rio de Janeiro, Brazil had a chance to examine the unusual bat up close from the collections of the American Museum of Natural History in New York, he realized he was looking at a new species altogether.

“This new species have been misidentified as Myotis simus since 1965,” Moratelli said in an email to Discovery News. “When I put Amazon and Bolivian specimens side-by-side I realized they were two different species.”

There are more than 100 species of Myotis bats in the world — sharing the trait of mouse-like ears. What makes this new species unique is its bright golden fur. It takes its name midastactus from the Greek legend of King Midas of the legendary golden touch.

The golden furry bat is believed to live only in the savannas of Bolivia where it feeds on small insects. A nocturnal mammal, the bat snoozes in nests during the day in hollow trees, under thatched roofs and in holes in the ground.

Although Moratelli believes the golden bat lives only in this area, so far, he hasn’t managed to capture one from the wild and has based his conclusions, published in the Journal of Mammalogy, on previous collections of the bat.

“In 2011, I spent two months in the Brazilian Savannah (in the boundary with Bolivia) trying to capture living individuals to get fresh tissues to perform DNA comparisons but none was captured,” said Moratelli.

Read more at Discovery News

2,100-Year-Old Royal Mausoleum Found in China

A 2,100-year-old mausoleum built for a king named Liu Fei has been discovered in modern-day Xuyi County in Jiangsu, China, archaeologists report.

Liu Fei died in 128 B.C. during the 26th year of his rule over a kingdom named Jiangdu, which was part of the Chinese empire.

Although the mausoleum had been plundered, archaeologists found that it still contained more than 10,000 artifacts, including treasures made of gold, silver, bronze, jade and lacquer. They also found severallife-size chariot and dozens of smaller chariots.

Excavated between 2009 and 2011, the mausoleum contains "three main tombs, 11 attendant tombs, two chariot-and-horse pits, two weaponry pits" and the remains of an enclosure wall that originally encompassed the complex, a team of Nanjing Museum archaeologists said in an article recently published in the journal Chinese Archaeology. The wall was originally about 1,608 feet (490 meters) long on each side.

The archaeologists said their work was a "rescue excavation," as the site was threatened by quarrying.

A large earthen mound — extending more than 492 feet (150 meters) — once covered the king's tomb, the archaeologists say. The tomb has two long shafts leading to a burial chamber that measured about 115 feet (35 m) long by 85 feet (26 m) wide.

When archaeologists entered the burial chamber they found that Liu Fei was provided with a vast assortment of goods for the afterlife.

Such goods would have been fitting for such a "luxurious" ruler. "Liu Fei admired daring and physical prowess. He built palaces and observation towers and invited to his court all the local heroes and strong men from everywhere around," wrote ancient historian Sima Qian (145-86 B.C.), as translated by Burton Watson. "His way of life was marked by extreme arrogance and luxury."

His burial chamber is divided into a series of corridors and small chambers. The chamber contained numerous weapons, including iron swords, spearheads, crossbow triggers, halberds (a two-handled pole weapon), knives and more than 20 chariot models (not life-size).

The archaeologists also found musical instruments, including chime bells, zither bridges (the zither is a stringed instrument) and jade tuning pegs decorated with a dragon design.

Liu Fei's financial needs were not neglected, as the archaeologists also found an ancient "treasury" holding more than 100,000 banliang coins, which contain a square hole in the center and were created by the first emperor of Chinaafter the country was unified. After the first emperor died in 210 B.C., banliang coins eventually fell out of use.

In another section of the burial chamber archaeologists found "utilities such as goose-shaped lamps, five-branched lamps, deer-shaped lamps, lamps with a chimney or with a saucer …." They also found a silver basin containing the inscription of "the office of the Jiangdu Kingdom."

The king was also provided with a kitchen and food for the afterlife. Archaeologists found an area in the burial chamber containing bronze cauldrons, tripods, steamers, wine vessels, cups and pitchers. They also found seashells, animal bones and fruit seeds. Several clay inscriptions found held the seal of the "culinary officer of the Jiangdu Kingdom."

Sadly, the king's coffins had been damaged and the body itself was gone. "Near the coffins many jade pieces and fragments, originally parts of the jade burial suit, were discovered. These pieces also indicate that the inner coffin, originally lacquered and inlaid with jade plaques, was exquisitely manufactured," the team writes.

A second tomb, which archaeologists call "M2," was found adjacent to the king's tomb. Although archaeologists don't know who was buried there it would have been someone of high status.

"Although it was looted, archaeologists still discovered pottery vessels, lacquer wares, bronzes, gold and silver objects, and jades, about 200 sets altogether," the team writes.

"The 'jade coffin' from M2 is the most significant discovery. Although the central chamber was looted, the structure of the jade coffin is still intact, which is the only undamaged jade coffin discovered in the history of Chinese archaeology," writes the team.

In addition to the chariot models and weapons found in the king's tomb, the mausoleum also contains two chariot-and-horse pits and two weapons pits holding swords, halberds, crossbow triggers and shields.

In one chariot-and-horse pit the archaeologists found five life-size chariots, placed east to west. "The lacquer and wooden parts of the chariots were all exquisitely decorated and well preserved," the team writes. Four of the chariots had bronze parts gilded with gold, while one chariot had bronze parts inlaid with gold and silver.

The second chariot pit contained about 50 model chariots. "Since a large quantity of iron ji (Chinese halberds) and iron swords were found, these were likely models of battle chariots," the team writes.

A series of 11 attendant tombs were found to the north of the king's tomb. By the second century B.C. human sacrifice had fallen out of use in China so the people buried in them probably were not killed when the king died.

Again, the archaeologists found rich burial goods. One tomb contained two gold belt hooks, one in the shape of a wild goose and the other a rabbit.

Another tomb contained artifacts engraved with the surname "Nao." Ancient records indicate that Liu Fei had a consort named "Lady Nao," whose beauty was so great that she would go on to be a consort for his son Liu Jian and then for another king named Liu Pengzu. Tomb inscriptions suggest the person buried in the tomb was related to her, the team says.

During the second century B.C. China was one of the largest, and wealthiest, empires on Earth, however, the power of its emperor was not absolute. During this time a number of kings co-existed under the control of the emperor. These kings could amass great wealth and, at times, they rebelled against the emperor.

About seven years after Liu Fei's death, the Chinese emperor seized control of Jiangdu Kingdom, because Liu Jian, who was Liu Fei's son and successor, allegedly plotted against the emperor.

Read more at Discovery News

Aug 3, 2014

Why is the Sun's atmosphere so much hotter than its surface? Nanoflares

Scientists have recently gathered some of the strongest evidence to date to explain what makes the sun's outer atmosphere so much hotter than its surface. The new observations of the small-scale extremely hot temperatures are consistent with only one current theory: something called nanoflares -- a constant peppering of impulsive bursts of heating, none of which can be individually detected -- provide the mysterious extra heat.

What's even more surprising is these new observations come from just six minutes worth of data from one of NASA's least expensive type of missions, a sounding rocket. The EUNIS mission, short for Extreme Ultraviolet Normal Incidence Spectrograph, launched on April 23, 2013, gathering a new snapshot of data every 1.3 seconds to track the properties of material over a wide range of temperatures in the complex solar atmosphere.

The sun's visible surface, called the photosphere, is some 6,000 Kelvins, while the corona regularly reaches temperatures which are 300 times as hot.

"That's a bit of a puzzle," said Jeff Brosius, a space scientist at Catholic University in Washington, D.C., and NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Things usually get cooler farther away from a hot source. When you're roasting a marshmallow you move it closer to the fire to cook it, not farther away."

Brosius is the first author of a paper on these results appearing in the Aug. 1, 2014, edition of The Astrophysical Journal.

Several theories have been offered for how the magnetic energy coursing through the corona is converted into the heat that raises the temperature. Different theories make different predictions about what kind of -- and what temperature -- material might be observable, but few observations have high enough resolution over a large enough area to distinguish between these predictions.

The EUNIS rocket, however, was equipped with a very sensitive version of an instrument called a spectrograph. Spectrographs gather information about how much material is present at a given temperature, by recording different wavelengths of light. To observe the extreme ultraviolet wavelengths necessary to distinguish between various coronal heating theories, such an instrument can only work properly in space, above the atmosphere surrounding Earth that blocks that ultraviolet light. So EUNIS flew up nearly 200 miles above the ground aboard a sounding rocket, a type of NASA mission that flies for only 15 minutes or so, and gathered about six minutes worth of observations from above the planet's air.

During its flight, EUNIS scanned a pre-determined region on the sun known to be magnetically complex, a so-called active region, which can often be the source of larger flares and coronal mass ejections. As light from the region streamed into its spectrograph, the instrument separated the light into its various wavelengths. Instead of producing a typical image of the sun, the wavelengths with larger amounts of light are each represented by a vertical line called an emission line. Each emission line, in turn, represents material at a unique temperature on the sun. Further analysis can identify the density and movement of the material as well.

The EUNIS spectrograph was tuned into a range of wavelengths useful for spotting material at temperatures of 10 million Kelvin -- temperatures that are a signature of nanoflares. Scientists have hypothesized that a myriad of nanoflares could heat up solar material in the atmosphere to temperatures of up to 10 million Kelvins. This material would cool very rapidly, producing ample solar material at the 1 to 3 million degrees regularly seen in the corona.

However, the faint presence of that extremely hot material should remain. Looking over their six minutes of data, the EUNIS team spotted a wavelength of light corresponding to that 10 million degree material. To spot this faint emission line was a triumph of the EUNIS instrument's resolution. The spectrograph was able to clearly and unambiguously distinguish the observations representing the extremely hot material.

"The fact that we were able to resolve this emission line so clearly from its neighbors is what makes spectroscopists like me stay awake at night with excitement," said Brosius. "This weak line observed over such a large fraction of an active region really gives us the strongest evidence yet for the presence of nanoflares."

There are a variety of theories for what mechanisms power these impulsive bursts of heat, the nanoflares. Moreover, other explanations have been offered for what is heating the corona. Scientists will continue to explore these ideas further, gathering additional observations as their tools and instruments improve. However, no other theory predicts material of this temperature in the corona, so this is a strong piece of evidence in favor of the nanoflare theory.

Read more at Science Daily

Bacteria Build Shelters from Salt, Hibernate There

The common bacterium E. coli (Escherichia coli) has another trick up its sleeve: in addition to making humans very sick, it can build a shelter out of salt, dry out and hang out there for, well, no one is sure how long.

And then ... and then ... when a drop of water is applied to the salt shelter, the bacterium springs back to life.

The finding has implications for the search for life on other planets. Where super-harsh conditions might lead researchers to dismiss the possibility that life could persist there, bacteria may simply lie in wait for a spritz of moisture.

"Given the richness and complexity of these formations, they may be used as biosignatures in the search for life in extremely dry environments outside our own planet, such as the surface of Mars or that of Jupiter's satellite, Europa," said biologist José María Gómez, from the Laboratory of BioMineralogy and Astrobiological Research (LBMARS, University of Valladolid-CSIC), Spain, in a press release.

Gómez made the discovery with his home microscope. He was looking at E. coli, a bacterium that lurks, among other places, on the surface of beef and can make humans very ill if the meat isn't cooked thoroughly.

"It was a complete surprise, a fully unexpected result, when I introduced E. coli cells into salt water and I realized that the bacteria had the ability to join the salt crystallisation and modulate the development and growth of the sodium chloride crystals,"

Read more at Discovery News