Mar 29, 2014

More male fish 'feminized' by pollution on Basque coast

Members of the Cell Biology in Environmental Toxicology group have discovered evidence of "feminization" of male fish in the estuaries of Gernika, Arriluze, Santurtzi, Plentzia, Ondarroa, Deba and Pasaia. The first cases (2007-2008) were detected in Urdaibai, and the most recent data confirm that they are also taking place in other estuaries. Pollutants acting as estrogens are responsible for this phenomenon which, among other changes, is causing ovocytes -- immature ova -- to appear in male fish.

The UPV/EHU's Cell Biology in Environmental Toxicology group has conducted research using thick-lipped grey mullet and has analysed specimens in six zones: Arriluze and Gernika in 2007 and 2008, and since then, Santurtzi, Plentzia, Ondarroa, Deba and Pasaia. The acquisition of feminine features by male fish has been detected, to a greater or lesser extent, in all the estuaries, not only in the characteristics of the gonads of the specimens analysed but also in various molecular markers. According to Miren P. Cajaraville, director of the research group, the results show that "endocrine disruption is a phenomenon that has spread all over our estuaries, which means that, as has been detected in other countries, we have a problem with pollutants."

Some of the emerging pollutants detected are in fact responsible for the "feminization" of male fish on the Basque coast and belong to the group of endocrine disrupting chemicals. Chemically, they are very different from each other, but they all have similar effects: due to their interaction with hormones, they destroy the hormone balance and can lead to the feminization or masculinization of the organism. As they are pollutants that have appeared recently, little is known as yet about their effects on the environment and on ecosystems. According to Cajaraville, "our discoveries are significant, because they enable us to know how far these pollutants have spread in our estuaries and rivers and what effects they have; that way, we will be able to adopt methods to prevent them reaching our waters, like legal regulations governing their use."

Despite the fact that they are new pollutants in terms of their effects, the "sources" of endocrine disrupting chemicals can be found in everyday products: plasticisers, pesticides, contraceptive pills, fragrances and detergents, among other things.

Some reach the waters after managing to get through the cleaning systems in wastewater treatment plants, and others as a result of industrial or farming activities. So, as far as the Urdaibai Biosphere Reserve is concerned, for example, "our main hypothesis," says Cajaraville, "is that they come from the water treatment plant. It was the first place we studied, and continues to be, by far, responsible for the highest percentage of recently appearing pollutants."

In any case, the UPV/EHU's research group found evidence of feminization in male thick-lipped grey mullet in all the estuaries analysed: in three out of the six estuaries (Gernika, Pasaia and Deba) appeared intersex fish, in other words, specimens whose testicles contained immature ova (depending on the area studied, the percentage ranged between 12% and 64%).What is more, all the estuaries have tested positive as far as the two main molecular indicators are concerned: most of the male fish (between 60% and 91%) had vitellogenin (a protein that, in principle, is only expressed in females) in the liver; in the brain, there were considerable levels of the gene expression that encodes Aromatase Cyp19a1b,a protein involved in oestrogen synthesising. Its expression in the male brain is a clear symptom of feminization.

Apart from measuring the feminization indicators in male fish populations, the research team also carried out a chemical analysis of the sampling areas: "All the time we worked in collaboration with analytical chemistry teams, and we characterised each spot from the chemical and biological points of view," stressed Cajaraville. During the 2007/2008 campaign they had the collaboration of the chemical team of the Institute of Environmental Diagnosis and Water Studies of the CSIC (Spanish National Scientific Research Council); later they were assisted by the UPV/EHU's department of Analytical Chemistry. According to Cajaraville, this is a "highly significant fact, since apart from demonstrating that there are clear biological indicators of fish feminization, in each of the places studied we have measured which pollutants have appeared recently and their respective concentrations, and we have confirmed the correlation existing between the presence of the pollutants and the feminization phenomenon." The pollutants were measured in the bile of the fish, and the said correlation has shown, according to Cajaraville, that it is the pollutants that are responsible for the feminization of the male fish.

Read more at Science Daily

Ancient African cattle first domesticated in Middle East, study reveals

Geneticist and anthropologists previously suspected that ancient Africans domesticated cattle native to the African continent nearly 10,000 years ago. Now, a team of University of Missouri researchers has completed the genetic history of 134 cattle breeds from around the world. In the process of completing this history, they found that ancient domesticated African cattle originated in the "Fertile Crescent," a region that covered modern day Iraq, Jordan, Syria and Israel.

Lead researcher Jared Decker, an assistant professor of animal science in the MU College of Agriculture, Food and Natural Resources, says the genetics of these African cattle breeds are similar to those of cattle first domesticated in the Middle East nearly 10,000 years ago, proving that those cattle were brought to Africa as farmers migrated south. Those cattle then interbred with wild cattle, or aurochs, which were native to the region, and changed their genetic makeup enough to confuse geneticists.

In their study published in PLOS Genetics, Decker and a team of international researchers compared the similarities and differences among the genetics of many different cattle breeds to determine how the breeds are related. Their research found mixing of native cattle in Indonesia with imports from India, European and African cattle in Italy and Spain, and European and Asian cattle in Korea and Japan. The MU researchers also determined that unique American cattle breeds, such as Texas longhorns, are the result of breeding between Spanish cattle, transported from Europe by explorers in the 16th century, and breeds of Zebu, or Brahman cattle from India imported into the U.S. from Brazil in the late 1800s. Decker says these discoveries help advance genetics and uncover important information about human history.

"In many ways, the history of cattle genetics mirrors human history," Decker said. "In the case of African cattle, anthropologists and geneticists used to suspect that domesticated African cattle were native to the continent, when in fact, they were brought by migrating peoples thousands of years ago. By better understanding the history of the animals we domesticate, we can better understand ourselves."

Decker also said that cattle breeding is important for animal farmers looking to maximize their herds' meat and dairy production. He says that understanding the genetic history of cattle breeds is important when looking for solutions to agricultural issues.

Read more at Science Daily

Mar 28, 2014

Heads Up, Lights Out Saturday for Earth Hour

Millions of people around the world are expected to go dark for an hour on Saturday, March 29, as part of the World Wildlife Fund’s annual Earth hour. Want to join in? Flip the switch and turn off your lights at 8:30 p.m. Saturday, local time.

"For us the symbolism or turning your lights off will always be important," Earth Hour's executive director Andy Ridley told The Guardian. "But the big thing for us has always been how to push it beyond the hour. The stage we're at now is to make it really easy for people from their handset, tablet or laptop to be able to do something pretty immediate to make a difference. That's the holy grail for us -- building a global collective movement, far beyond the event, where the event becomes a kind of inspiration but the movement is really the essence of it."

This year the WWF launched Earth Hour Blue, a crowdsourcing project for environmental and conservation projects around the world.

Earth Hour was first launched in Sydney, Australia in 2007, as a way to promote conservation and bring attention to global warming. People in more than 150 countries now participate in the event. Here are some of the notable landmarks that plan to observe Earth Hour:

Seattle’s Space Needle, the St. Louis Arch, parts of the Vegas strip, the Empire State Building, Berlin’s Brandenburg Gate, Buckingham Palace, the Burj Khalifa in Dubai and the Kremlin and Red Square in Moscow.

Read more at Discovery News

Extreme Earth Life Can Aid Search for Alien Lifeforms

Until we understand the limits of life, it will be difficult to determine if alien planets can host any living beings, scientists say.

By studying Earth-bound "extremophiles" — microbes that survive in harsh conditions, such as hot and acid-filled ocean vents — scientists can understand the limits of temperature, pressure and acidity that support life on Earth more fully. These finding may also be applied to other planets.

These life-supporting parameters could be revised, however, if a new extremophile is discovered or biology is different on another world, said John Baross, a researcher at the University of Washington who focuses on these microbes, on March 17.

"This is very much a discovery-based science, and there is so much we still don't understand," Baross said during the Search for Life Beyond the Solar System conference in Tucson, Ariz.

One emerging field of research examines microbes living in a low carbon and energy environment, like the parts of the ocean below where sunlight can reach through the waters.

Considering slower evolution over millions of years in these reaches is a "totally new ballgame" for alien planet researchers, Baross said.

Musings on life beyond Earth

Hosts for the conference include the University of Arizona's Steward Observatory as well as the Vatican Observatory, which is based just outside of Rome. Historically, science and religion have at times come to loggerheads at the Vatican. For example, when Galileo Galilei discovered moons around Jupiter in 1610, he said the Earth orbits sun rather than the other way around, in defiance of the church.

The Vatican Observatory has made its own contributions to astronomy, pointed out José Funes, its current director. The 19th-century director Angelo Secchi was one of the first scientists to authoritatively say that the sun is a star, Funes said.

Secchi, like scientists today, also mused on the possibility of life beyond Earth, a theme that Vatican scientists discussed at the conference, Funes added, putting a passage from Secchi's 1870 book, "Le Soleil" (The Sun) on the screen.

"What to think of these stars without any doubt similar to our sun," the passage read, "destined like the sun to keep alive an enormous quantity of creatures of every kind?"

Synthetic life

Finding alien life will be a complex task, other scientists pointed out. Perhaps extraterrestrials will require a "wet" planet like Earth and a "dry" planet like Mars to pass material back and forth, said biochemist Steven Benner of The Westheimer Institute for Science and Technology in Florida.

Benner suggested that it might be easier for organisms to come alive in a dry environment, but that it would take water to make sustained life possible.

Other researchers, meanwhile, are trying to better understand the parameters of life by creating synthetic lifeforms to see how they will behave in different environments. Lynn Rothschild of NASA's Ames Research Center, is the faculty adviser for Brown University and Stanford University students participating in the annual International Genetically Engineered Machine competition.

Read more at Discovery News

Could 'Planet X' Still be Lurking Out There?

The hunt for the hypothetical "Planet X" has been fruitless so far, but that doesn't mean astronomers are calling it off.

A new analysis of data collected by NASA's Wide-Field Infrared Survey Explorer (WISE) spacecraft revealed no sign of the mysterious Planet X hypothesized to exist in the outer solar system. But scientists are keeping up the search for a planet or dim star far from the sun.

"I think astronomers will continue to search for a distant companion to the sun with every new, deeper survey," Kevin Luhman of the University of Pennsylvania told by email. Luhman, who studies low-mass stars and "failed stars" known as brown dwarfs, recently published the results of his search for Planet X using WISE.

"We have a natural desire to better determine the contents of our solar system," Luhman said. "There's a vast volume of space in the outer solar system, and we would like to know what's out there."

And a recent find may give a boost to the hunt for Planet X. On Wednesday (March 26), researchers announced they had discovered a dwarf planet orbiting the sun in a distant, largely unexplored region known as the inner Oort Cloud.

Further, the orbits of the newfound object, known as 2012 VP113, and some of its neighbors are consistent with (though by no means proof of) the existence of a planet-size "perturber" far from the sun — perhaps so distant that it cannot be detected with current instruments.

An Unseen Companion

For more than a century, astronomers have considered the possibility that another massive body exists in the outer solar system.

Percival Lowell coined the term "Planet X" at the turn of the 20th century to refer to an undiscovered large planet that could be responsible for perturbing the orbits of Uranus and Neptune. More recently, the idea grew to incorporate a possible dwarf-star companion to the sun, nicknamed "Nemesis."

In the 1980s, scientists suggested that a solar companion could be responsible for causing mass extinctions on Earth every 26 million years. They theorized that a small, dim star or a large brown dwarf -- a body larger than a planet but too small to ignite the fusion reactions that power stars -- could periodically pass through the Oort Cloud, the faraway comet repository that surrounds the solar system.

Gravitational tugs from this body could send a rain of comets hurtling toward the inner solar system, where some would collide with Earth and threaten any life that existed.

The Infrared Astronomical Satellite (IRAS), the first space telescope to scan the entire sky in the infrared, collected a wealth of data in the early 1980s but found no sign of the putative distant object. More detailed data came back from NASA's Two Micron All-Sky Survey (2MASS) a decade and a half later, with the same result.

But that didn't end the search for the mysterious body. A 1999 study, for example, claimed to find subtle anomalies in the orbits of comets — possible evidence for a distant solar companion. A follow-up study by the same authors in 2011 made the same claim. The team of astronomers suggested that the oddities could be the result of a gas giant planet that they nicknamed "Tyche."

Still scanning the heavens

Most astronomers today don't give much credence to the claims of historical evidence for a companion star or distant planet, Luhman said. Yet the hunt continues, because the possibility such a body could exist is always there. (An Earth-size object would likely be undetectable with current instruments if it lay about 250 Earth-sun distances away, researchers say.)

The recent results from WISE provide an even more detailed look at cool bodies within the solar system. Luhman's work, published in The Astrophysical Journal, found no sign of Saturn-size bodies to a distance of 10,000 times the Earth-sun distance. (The distance from Earth to the sun, known as an astronomical unit or AU, is about 93 million miles, or 150 million kilometers).

The survey also sought Jupiter-like and larger bodies, which would include brown dwarfs and low-mass stars, as far away as 26,000 AU. It turned up no hint of the hypothesized body.

If scientists hadn't suggested that an unseen star or planet could be affecting life on Earth, would astronomers still search for Planet X? Luhman thinks so.

"Even if no one had previously claimed to find evidence of a large body in the solar system, one would naturally search for an object of that kind with every new all-sky survey that is able to see fainter objects than the previous survey," he said.

Improving technology could make the difference when it comes to turning up a solar companion. According to Luhman, there is a small chance that a distant companion to the sun could have been missed if it was aligned close to a bright star. Data from the bright star could then have overwhelmed the companion, much as the sun overpowers a flashlight beam.

Read more at Discovery News

The 6-Foot Earthworm That Sounds Like a Draining Bathtub

Giant Gippsland earthworms grow to 6 feet long. Here one does a pretty half-assed impression of the letter M.
They say everything in Australia can kill you: crazy-poisonous eastern brown snakes, enormous saltwater crocodiles, and, until recently, the late ill-tempered supercriminal Mark “Chopper” Read. But the truth is there are plenty of harmless animals and even a handful of harmless humans in Australia.

The continent’s long isolation has given rise to an incredibly unique diversity of life that, yes, includes some extremely lethal critters. But perhaps its most remarkable creature is a gentle, extremely delicate colossus few have had the privilege of glimpsing: the giant Gippsland earthworm, which can grow to some 6 feet long. Give it a stretch–only if it’s already dead, you chucklehead–and it can easily double in length.

These elusive monsters have been known to science only since the late 1800s, when workers unearthed a specimen while surveying a rail line. Mistaking it for a snake, with great care they took it to a professor at the University of Melbourne, who I hope informed them that snakes generally have, you know, teeth and scales and stuff.

This is an extremely vulnerable species, isolated to just 150 square miles at the southeast tip of Australia. Its habitat, once dense forests, has been almost entirely converted to farmland, where tilling and toxins have pushed them to the brink of extinction. But while these worms only surface during heavy rains to avoid drowning in soggy soil, you can actually hear them underfoot.

“Burrows that are occupied by giant Gippsland earthworms have very wet walls,” said biologist Beverley D. Van Praagh, who has studied the creatures for over 20 years, “so when the earthworms move quickly within their burrows, it makes a gurgling sound that is quite loud and can be heard above ground. The sound is a bit like water draining out of a bath and has been known to terrify the uninitiated.”

Life is just one long mud bath for the giant earthworm. The bourgeois lifestyle, though, takes its toll. The worm grows fat and overly content, spending its days sunning and abusing the help before eventually descending into inheritance disputes with its ingrate children.
The giant earthworm burrows through relatively firm soil up to 5 feet deep, using its muscular head to chew through the substrate while ingesting fungi, bacteria, algae, and other microbes. They don’t have teeth, but they do have a gizzard, where small rocks that the worm has eaten help grind up food. (Some birds do this as well, by the way, as did their ancestors the dinosaurs. As do some enterprising human children, though it does them no real good.)

The wastes they expel at the other end are called castings, and the worms actually block their burrows with them, which would seem, well, irresponsible.

“You would think that if they had permanent burrows and block part of their systems with cast that they would run out of room unless they built more burrows,” said Van Praagh. “It does appear that they go back to the same spot and cast in areas where they have already left other cast material, but clearly we do not have the full story on their toilet habitats and burrow building.”

Also still unknown is how they mate in burrows barely wide enough for one. Could they in fact be emerging to mate on the surface?

“Many other species of earthworms mate above ground and don’t have permanent burrows,” said Van Praagh, “but giant Gippsland earthworms are very sluggish on the surface and they would be very vulnerable to desiccation and predators if they stayed above ground for too long.” But they may just have a sexy trick up their sleeves for mating underground. “These worms are fairly flexible, so it’s possible they extend their length to make themselves thinner,” Van Praagh added, “thereby allowing the two worms to couple side by side within their burrows.”

Individuals have both male and female sex organs, and Van Praagh reckons that they align their naughty bits and hand off sperm (here, trade ya!), which is stored in chambers called spermathecae. Van Praagh has found that the worms will store sperm year-round, which means “that they may potentially mate whenever they meet and then store the sperm, ready for producing eggs whenever conditions are favorable. This could be advantageous for worms in low densities and poor dispersal abilities.”

Fertilization actually occurs inside the egg cocoon, which a worm will produce only once a year. When the worms finally decide they’re financially stable and mature enough to have a child, a structure called a clitellum releases an egg case, which slides forward and gathers eggs and sperm. The egg is then laid in a chamber branching off from the burrow, and can take as many as 12 months to hatch.

When it does, at a foot long the baby is already huge (for perspective, that’s as big as a foot-long Subway sandwich … I think). Its growth rate for the rest of its life, though, is slow. And it’s based on this rate that Van Praagh estimates the worm can live as long as 10 years–and probably a lot more.

But this sluggish growth, combined with a tiny distribution and the giant worm’s positively lazy sex life of just one cocoon a year, pose a serious problem for a creature living in the anthropocene–the epoch of devastating human impacts on the planet.

Read more at Wired Science

Mar 27, 2014

Ancient sea creatures filtered food like modern whales

Ancient, giant marine animals used bizarre facial appendages to filter food from the ocean, according to new fossils discovered in northern Greenland. The new study, led by the University of Bristol and published today in Nature, describes how the strange species, called Tamisiocaris, used these huge, specialized appendages to filter plankton, similar to the way modern blue whales feed today.

The animals lived 520 million years ago during the Early Cambrian, a period known as the 'Cambrian Explosion' in which all the major animal groups and complex ecosystems suddenly appeared. Tamisiocaris belongs to a group of animals called anomalocarids, a type of early arthropod that included the largest and some of the most iconic animals of the Cambrian period. They swam using flaps down either side of the body and had large appendages in front of their mouths that they most likely used to capture larger prey, such as trilobites.

However, the newly discovered fossils show that those predators also evolved into suspension feeders, their grasping appendages morphing into a filtering apparatus that could be swept like a net through the water, trapping small crustaceans and other organisms as small as half a millimetre in size.

The evolutionary trend that led from large, apex predators to gentle, suspension-feeding giants during the highly productive Cambrian period is one that has also taken place several other times throughout Earth's history, according to lead author Dr Jakob Vinther, a lecturer in macroevolution at the University of Bristol.

Dr Vinther said: "These primitive arthropods were, ecologically speaking, the sharks and whales of the Cambrian era. In both sharks and whales, some species evolved into suspension feeders and became gigantic, slow-moving animals that in turn fed on the smallest animals in the water."

In order to fully understand how the Tamisiocaris might have fed, the researchers created a 3D computer animation of the feeding appendage to explore the range of movements it could have made.

"Tamisiocaris would have been a sweep net feeder, collecting particles in the fine mesh formed when it curled its appendage up against its mouth," said Dr Martin Stein of the University of Copenhagen, who created the computer animation. "This is a rare instance when you can actually say something concrete about the feeding ecology of these types of ancient creatures with some confidence."

The discovery also helps highlight just how productive the Cambrian period was, showing how vastly different species of anomalocaridids evolved at that time, and provides further insight into the ecosystems that existed hundreds of millions of years ago.

"The fact that large, free-swimming suspension feeders roamed the oceans tells us a lot about the ecosystem," Dr Vinther said. "Feeding on the smallest particles by filtering them out of the water while actively swimming around requires a lot of energy -- and therefore lots of food."

Read more at Science Daily

Fossil Detectives Close the Case on Prehistoric Spider Footprints

These are footprints left behind when a tarantula-size arachnid crawled over the sand of what’s now northern Arizona, 260 million years ago. We don’t know where it was going or what it was doing, but each time the critter pressed one of its eight feet into the ground, it left a tiny, cup-shaped imprint in the dewy grains.

The sand’s moisture helped preserve the imprints of the creature’s journey: As the sand dried out, the delicate prints solidified. Over millennia, layers of sand covered the arachnid’s footwork and hardened into rock. Then, in 1968, the rock and its footprints were pulled from the Arizona desert; it now lives in The Raymond M. Alf Museum of Paleontology, where visitors can stop by and see the footsteps of an ancient spider.

Well, it’s probably a spider. There are many clues that suggest as much, though the organism responsible for these tracks, which span 2.5 inches, is long gone.

“You just don’t have fossil spiders from this part of the world,” says Alf museum curator Andrew Farke. “They’re too squishy to preserve very well.”

Deciphering the traces left by organisms – whether footprints, tracks, trails, burrows – is the realm of a discipline known as ichnology. Basically, ichnology is what you would get if you mixed Sherlock Holmes with felonious fossils. Ichnologists look at the shapes of tracks, their distribution, and other clues to learn more about the animals and the environment at the time the tracks were made.

We didn’t always know what spider footprints looked like. When paleontologist Raymond Alf (the museum’s namesake) retrieved the fossil in 1968, he did some experimenting to determine whether the eight-legged footprints were the work of a spider or a scorpion or something else. “He got some spiders and inked up their little legs on an inkpad and had them run across paper,” Farke says. “In his opinion, these things were fairly close matches for a spider.”

Then, two decades ago, geologist Christa Sadler redid the experiment. She set up a 4-meter long sandy runway with a slight hill in the middle. She sprayed water on some of the sand and kept the rest dry. Then she released tarantulas and scorpions onto the runway. She varied the speeds at which they could traverse the course by introducing a headwind, and recorded how their footprints changed with speed, angle, and moisture. In the end, she reached the same conclusion about this fossil: It most closely resembles the footwork of a tarantula.

But there’s still a lot to learn about spider footprints — especially those belonging to prehistoric arachnids.

We checked in with Emory University ichnologist Anthony Martin, to see if modern fossil forensics has anything to tell us about this fossil.

He thinks Alf and Sadler were on the right track, so to speak. When most people look at this fossil, they might immediately think the tracks were made by something with four toes, but Martin’s trained eyes see something else: The unmistakable imprints of an eight-legged creature, one with an “out of phase, alternating” gait. In other words, the creature didn’t hop.

“The legs on each side of the spider are moving at different times,” he says. “This is a very typical pattern with terrestrial arthropods.”

Read more at Wired Science

An Unexpected Discovery in the Brains of Autistic Children

Nobody knows what causes autism, a condition that varies so widely in severity that some people on the spectrum achieve enviable fame and success while others require lifelong assistance due to severe problems with communication, cognition, and behavior. Scientists have found countless clues, but so far they don’t quite add up. The genetics is complicated. The neuroscience is conflicted.

Now, a new study adds an intriguing, unexpected, and sure-to-be controversial finding to the mix: It suggests the brains of children with autism contain small patches where the normally ordered arrangement of neurons in the cerebral cortex is disrupted. “We’ve found locations where there appears to be a failure of normal development,” said Eric Courchesne, a neuroscientist at the University of California, San Diego and an author of the study, which appears today in the New England Journal of Medicine.

“It’s been really difficult to identify a lesion or anything in the brain that’s specific and diagnostic of autism,” said Thomas Insel, director of the National Institute of Mental Health, one of several agencies that funded the project. The new study is notable because it applies sophisticated molecular labeling methods to postmortem tissue from people with autism who died as children, which is incredibly hard to come by, Insel says.

“If it’s real, if it’s replicated and it’s a consistent finding, it’s more evidence that autism starts prenatally and only manifests itself when kids start to have trouble with language or social behavior around age two or three,” Insel said. “These kinds of changes in cellular architecture would happen during brain development, probably around the first part of the second trimester.”

The cortex is the thin sheet of tissue on the surface of the brain. We humans have so much of it that it’s folded up to fit inside our skulls, giving our brains their wrinkly appearance. The cortex plays an important role in everything from basic functions like planning movements and making sense of information from our eyes and ears, to more advanced stuff like language and abstract thought.

If you cut a cross-section through the cortex and looked at it under a microscope, you’d see that it has a consistent cellular architecture, with six distinct layers, each inhabited by certain types of neurons with a certain pattern of connections with other neurons. This uniform organization, many neuroscientists think, is what makes the cortex such a powerful and flexible computer.

But that organization appears to be messed up in spots in many children with autism, according to the new study.

Courchesne and colleagues examined post-mortem brain tissue from 22 children who died between the ages of 2 and 15 — half had autism, half did not. The symptoms of those who had it varied from mild to severe. With help from Ed Lein and other scientists at the Allen Brain Institute, the team applied genetic markers that label specific cell types and specific layers of cortex.

In 10 of 11 of the autistic brains, they found patches of cortex that didn’t follow the normal rules. The patches were a few millimeters across (roughly a quarter to half an inch). In some patches, a specific layer was missing. In others, certain cells weren’t there. The details varied from case to case.

The researchers found these abnormalities in the temporal and prefrontal cortex, areas with roles in language and cognition that are — in a very broad and hand-wavey sort of way — relevant to the symptoms of autism. They did not see them in the occipital cortex, a region primarily associated with vision, which isn’t typically disrupted in autism. Nor did they see them in the brains of 10 of the 11 children without autism. (The one child in this group without autism who had patches of scrambled cortex also had a history of severe seizures, which doesn’t exactly explain that finding, but might be relevant, Courchesne says).

“It’s intriguing to find something consistent like this,” said Helen Barbas, a neuroscientist at Boston University who wasn’t involved in the new study. But she’s less sure about what it means.

One popular hypothesis is that autism results from altered connections within or between regions of the cortex. “The cortex is a huge communication system,” Barbas said. “If you have an abnormality in the structure of cortex, it’s going to affect connectivity.” At this point though, it’s not possible to connect the dots between the scrambled bits of cortex described in the new study and the type of altered connectivity Barbas and others have found previously. “It raises a lot of questions, and that’s good.”

 Courchesne acknowledges the new study is just a start. The researchers only had access to small chunks of brain tissue, so they can’t say how widespread the disordered patches were in any given person, let alone how common they are overall in the brains of people with autism (or without it, for that matter). For the same reason, it’s not clear yet whether there’s any relationship between the severity — or the type — of autism symptoms and the number or location of scrambled patches of cortex.

What could cause these abnormalities isn’t clear, but Courchesne thinks genetics and environment could both play a role. The trigger could be some relatively common (but currently unknown) thing encountered by pregnant mothers, Courchesne suggests, but different individuals might vary in their genetic susceptibility to it — and in their genetic potential to compensate for it.

The findings might also be consistent with spontaneous gene mutations, which have been implicated by several teams of autism researchers in recent years, says Robert Hevner, a neuropathologist and neuroscientist at the University of Washington. Unlike the inherited gene mutations passed down from parent to offspring, spontaneous mutations occur later, during development.

“As billions of cells in our body and brain are dividing, mistakes get made,” Hevner said. Because those mistakes affect some cells and not others, they can create a mosaic-like pattern of abnormalities. “If there are mutations occurring on a small scale during brain development, we might see some changes like they’re showing here.”

Read more at Wired Science

Roman Emperor Dressed as Pharaoh in Newfound Carving

An ancient stone carving on the walls of an Egyptian temple depicts the Roman emperor Claudius dressed as an Egyptian pharaoh, wearing an elaborate crown, a team of researchers has discovered.

In the carving, Emperor Claudius, who reigned from A.D. 41 to 54, is shown erecting a giant pole with a lunar crescent at the top. Eight men, each wearing two feathers, are shown climbing the supporting poles, with their legs dangling in midair.

Egyptian hieroglyphs in the carving call Claudius the "Son of Ra, Lord of the Crowns," and say he is "King of Upper and Lower Egypt, Lord of the Two Lands." The hieroglyphs say he is raising the pole of the tent (or cult chapel) of Min (an ancient Egyptian god of fertility and power) and notes a date indicating a ritual like this took place around the summertime researchers say. It would have taken place even though Claudius never visited Egypt. A cult chapel is a place of worship and a tent could also be used for this purpose.

The elaborate crown on Claudius consists of three rushes (plants) set on ram horns with three falcons sitting on top. Three solar discs representing the sun (one for each plant) are shown in front of the rushes. Egyptian rulers are shown wearing crowns like this relatively late in ancient Egyptian history, mainly after 332 B.C., and they were worn only in Egypt. The Roman Empire took over Egypt in 30 B.C., and while the Roman emperors were not Egyptian, they were still depicted as pharaohs Egyptologists have noted.

In the recently discovered carving, the god Min is shown wearing his own crown and has an erect penis, because Min was a god of fertility, the researchers said. The hieroglyphs describe Min as "the one who brings into control the warhorses, whose fear is in the Two Lands." Min tells Claudius, "I give you the (southern) foreign lands," which researchers say could be a reference to the deserts surrounding the Nile River, where minerals could be quarried.

The scene was discovered on the western exterior wall of the Temple of Isis at Shanhur, located on the east bank of the Nile River about 12 miles (20 kilometers) north of Luxor. It is an Egyptian temple built and decorated during the Roman occupation under Augustus (who reigned from about 30 B.C. to A.D. 14) through to Trajan (who reigned from A.D. 98 to 117). The pole-raising scene was first found during the 2000-2001 excavation season and was recorded in full during the 2010 epigraphic (recording) season. The temple originally had 36 scenes on each of its eastern and western exterior walls, and this new scene, protected for millennia by a layer of dirt, is one of the best preserved.

The study was published recently in the journal Zeitschrift für ägyptische Sprache und Altertumskunde by Martina Minas-Nerpel, a Reader (the American equivalent of an associate professor) at Swansea University in the United Kingdom, and Marleen De Meyer, a postdoctoral researcher at KU Leuven University in Belgium. Careful line drawings of the scene were done by Troy Sagrillo, a senior lecturer at Swansea University.

Roman pharaohs

Although Cleopatrais often called the "last pharaoh of Egypt," the Egyptian priests depicted the Roman emperors as pharaohs up until the fourth century A.D. The Roman emperors allowed, or even encouraged, these depictions in Egyptian temples in order to keep Egypt — which was an important Roman province — stable.

"Although we know that Claudius, as most Roman emperors, never visited Egypt, his rule over the land at the Nile and the desert regions was legitimized through cultic means," Minas-Nerpel and De Meyer wrote in the journal article. "By decorating the exterior temple wall with this ritual, Claudius theoretically received Min's characteristics and thus his ability to rule over Egypt."

The researchers noted that similar scenes showing a pole being raised for the god Min date as far back as 4,300 years ago, during the age when pyramids were being built in Egypt. This tradition of creating pole-raising scenes was continued into the period of Roman rule.

Real-life ritual

In addition, the date on the carving indicates that a ritual like this took place in real life, the researchers said, adding that people may have climbed the central pole of the chapel of Min. In fact, a priest may have stood in for the absent Claudius, and a statue could have been used to represent Min, Minas-Nerpel said.

"What we see depicted on the temple scene is the ideal scenario," Minas-Nerpel told Live Science. She added that, even before the Romans took over Egypt in 30 B.C., Egypt's pharaohs were unable to take part in each temple ceremony in person, and stand-ins would have been necessary.

Lettuce scene

Another ritual offering at the Shanhur temple depicted at the axially corresponding scene on the eastern exterior wall shows Claudius giving an offering of lettuce to Min, which symbolizes the continued fertility of Egypt. It is located on the east wall and did not have to be excavated. In this scene, the Egyptian god Horus (shown as a child) is depicted between the two.

"[Take for] you the lettuce in order to unite it with your body (or phallus)," Claudius says to Min in hieroglyphs shown on the depiction. At one point, Claudius says, "One is in fear when seeing your face."

The two scenes highlight fertility and victorious power, both of which were important for legitimizing the rule of an absent Roman emperor who wanted to control Egypt, Minas-Nerpel and De Meyer wrote.

Read more at Discovery News

Mar 26, 2014

1,300-Year-Old Egyptian Mummy Had Biblical Tattoo

A mummy of an Egyptian woman dating back to 700 A.D. has been scanned and stripped to reveal a tattoo on her thigh that displays the name of the biblical archangel Michael.

The discovery, announced by researchers at the British Museum over the weekend, was made during a research project that used advanced medical scans, including Computed Tomography (CT) images, to examine Egyptian mummies at a number of hospitals in the United Kingdom last year.

The woman’s body was wrapped in a woolen and linen cloth before burial, and her remains were mummified in the desert heat. As deciphered by curators, the tattoo on her thigh, written in ancient Greek, reads Μιχαήλ, transliterated as M-I-X-A-H-A, or Michael.

Curators at the museum speculate that the tattoo was a symbol worn for religious and spiritual protection, though they declined to offer additional details.

“Like Greeks and Romans across the Mediterranean, the portion of the population that was literate was fascinated by the shapes of letters and delighted in making designs with letters in names. Hence, we have the odd shape of the tattoo composed of the letters.”

Placing the name of a powerful heavenly protector on one's body by a tattoo or amulet was very common in antiquity, Tilley told “Christian women who were pregnant often placed amulets with divine or angelic names on bands on their abdomens to insure a safe delivery of their child,” she said.

“Placing the name on the inner thigh, as with this mummy, may have had some meaning for the hopes of childbirth or protection against sexual violation, as in ‘This body is claimed and protected.’ Michael is an obvious identity for a tattoo, as this is the most powerful of angels.”

Christian Gnostics, religious cultists in that era, were especially interested in the names and functions of intermediary beings between humans and the divine, Tilley noted.

“The Gospel of Truth and the Book of Enoch were both popular among them and have much about an angel whose story sounds very much like that of Archangel Michael in many Christian stories, the angel who led the heavenly army against Satan and the Fallen Angels.”

She added that Christians were not the only ones to use the names of angelic powers in ancient days. “Jews of antiquity were fascinated by the identity and nature of angels,” she said.

Villanova University biology professor Michael Zimmerman, who also has used advanced technologies to study Egyptian mummies, said this kind of find has been sought for years.

“I did participate in an expedition to the Dakhleh Oasis in Egypt's western desert several years ago,” he told “This was an early Christian site (around 200 AD), and the deceased were still being mummified, by simply being dried in the very hot climate.

“We did not see any tattoos on those mummies, so the British Museum find is remarkable.”

The museum, which is located in London, will reveal what it has learned about this and seven other mummies in “Ancient Lives: New Discoveries,” an exhibition scheduled to run from May 22 to Nov. 30.

John Taylor, lead curator of the ancient Egypt and Sudan department at the museum, told a local newspaper over the weekend that the exhibition will tell the story of the lives of eight people from antiquity, portraying them as full human beings, rather than as archeological objects.

Using sophisticated medical imaging usually reserved to study strokes and heart attacks, the research team discovered that these eight ancient individuals, whose remains have been held in the museum for some time, had many of the same traits that modern man does, including dental problems, high cholesterol levels and tattoos.

Read more at Discovery News

16th-Century Masterpiece Reveals Cheese Glue Recipe

Sticky cheese might be the secret behind one of the most intriguing Mannerist paintings, according to a preliminary investigation carried out during restoration work.

Restorers had wondered what holds together the five poplar wood planks which make up “Visitation,” an enigmatic work by the 16th-century Mannerist Jacopo Pontormo.

“We believe they were pieced together with a caseine-based glue,” restorer Daniele Rossi told Discovery News. Caseine is a group of proteins commonly found in mammalian milk.

“Cheese glue was very popular at that time, and was normally used to join wood planks. We are going to carry out special chemical analyses for bindings to get a definitive answer,” Rossi said.

Described in the 16th-century Compendium of Rational Secrets as a “great secret of nature, a “super glue which withstands dampness and heat,” cheese glue was already detailed in the artists’ manuals of both Theophilus, a 12th-century German monk and 15th-century Italian painter Cennino Cennini.

The recipe for the potent adhesive relied on polypeptide casein protein molecules, and included ingredients such as hot water and quicklime. The goat or cow cheese-based concoction resulted in a sticky and thick compound which dried hard as stone, making it extremely hard for wood joints to separate.

“Whatever glue was used there, it was a powerful one. It’s still holding after five centuries,” Rossi said.

The source of inspiration for “The Greeting,” a video installation presented at the 1995 Venice Biennial by the Italian American artist Bill Viola, the dream-like Visitation is now the centerpiece of an exhibition on Mannerist artists Jacopo Carucci, also known as Pontormo (1494-1557), and Giovan Battista di Jacopo, a.k.a. Rosso Fiorentino (1494-1540) which runs in Florence through July 20.

Pontormo was one of the last artists of the Florentine Renaissance. He was a pupil of Leonardo da Vinci and Andrea del Sarto, and one of the earliest of the Mannerist school, a style of art developed in Italy following the High Renaissance, which emphasized mental conception over realistic depiction.

Pontormo completed the Visitation around 1528-1529, but the oil painting remained almost unknown until 1904, when it was rediscovered in the church of San Michele in Carmignano, a village west of Florence, and attributed to Pontormo.

The painting depicts in an almost metaphysical way the biblical meeting of the Virgin Mary, pregnant with Jesus, and Elisabeth, pregnant with St. John the Baptist. Staring fixedly into space, two statuesque figures in the background represent their alter egos.

The younger of the two wears the same color clothing of the Virgin Mary, but reversed. The older one appears to be Elizabeth shown in a sort of doubling.

“This intensely abstract atmosphere is sustained by the disproportionate size of the figures in comparison to the Florentine architectural backdrop and by the artist’s multiplication – as though in a mirror – of the number of figures witnessing the scene,” art critic Antonio Geremicca wrote in the exhibition catalog.

“These figurative devices make it more complicated to interpret the painting, whose significance scholars have yet to fathom in full,” he added.

Rossi’s restoration might help acquire new clues.

In addition to finding the super glue, the restorer filled 1,673 woodworm holes and removed the heavy repainting of past restorations. Incisive, luminous colors which previous interventions covered with a yellow varnish, re-emerged in full glory.

Read more at Discovery News

Secrets of the Viking Sun-Compass -- After Dark

Viking sailors may have been able to navigate after sunset, despite having no magnetic compasses and relying on sun compasses, says a team of researchers from Hungary and Sweden.

The trick may have been to combine the power of a sun-compass, which is a sort of modified sundial, with that of sunstones to create what they are calling a "twilight board."

"The recently identified calcite crystal found between the navigational tools of 16th-century European ship wreck hints that they could play some role in marine navigation" reports Balázs Bernáth and his colleagues in the Proceedings of the Royal Society A.

To test out if such twilight boards might have existed, the team examined a fragment of an 11th-century dial found in Uunartoq, Greenland, and attempted to extrapolate its features into something that would allow Viking navigators to detect the position of the sun from the twilight glow on the horizon passing through two sunstones.

If the difficult technique was employed, it could have allowed navigation well after sunset, since the twilight glow can last all night long at high latitudes in summer. Sunstones are recorded in Viking sagas as being employed to navigate on cloudy days, although what the stones were and how they worked remains lost knowledge.

The first step in regaining that knowledge was taken a few years ago by physicist Guy Ropars of the University of Rennes in France. Ropars and his team experimented with a potential sunstone that was recovered from a British ship which sunk in 1592. They applied partially polarized laser light on the calcite crystal -- similar to the kind of light that would make it through clouds (direct, unfiltered sunlight is not polarized).

By turning the crystal they found that a single angle where the crystal splits the light and transmits both unpolarized and polarized light beams at equal strength. This angle of equal brightness of the two beams of light in the crystal could be used by navigators to then determine the angle of the sun in the sky -- without actually being able to see the sun.

The twilight board would have used the same approach, argues Bernáth, but instead of being used during the day to navigate under clouds, it would use the light in the sky after sunset, along with a specially marked dial, perhaps one like that found in Uunartoq.

"Developing a twilight board is surely not beyond the capabilities of sea-faring people," Bernáth opined. "Sunstones are mentioned in written sources and they could be used during civil twilight, although it is not trivial how one can accurately estimate the position of the sun with them."

Read more at Discovery News

Small World Discovered Beyond Pluto

After a decade of searching, astronomers have found a second dwarf-like planet far beyond Pluto and its Kuiper Belt cousins, a presumed no-man’s land that may turn out to be anything but.

How Sedna, which was discovered in 2003, and its newly found neighbor, designated 2012 VP 2113 by the Minor Planet Center, came to settle in orbits so far from the sun is a mystery.

Sedna comes no closer than about 76 times as far from the sun as Earth, or 76 astronomical units. The most distant leg of its 11,400-year orbit is about 1,000 astronomical units.

Newly found VP 2113’s closest approach to the sun is about 80 astronomical units and its greatest distance is 452 astronomical units. The small world is roughly 280 miles (450 kilometers) wide, less than half the estimated diameter of Sedna.

Neither body can be explained by the present structure of the solar system, with its four rocky planets, four outer gas giant planets, disk of small icy Kuiper belt objects beyond Neptune and the comet-rich spherical Oort Cloud located some 10,000 times farther from the sun than Earth.

“Something else earlier on in the history of the solar system had to put them on these orbits,” astronomer Megan Schwamb, with Academia Sinica in Taipei, Taiwan, wrote in an email to Discovery News.

One theory is that a sister star to the sun, jointly incubated in a long-disbanded stellar nursery, gravitationally nudged some of the bodies in the Oort Cloud inward, creating a new and stable orbital subdivision.

Option two is that another planet at least as big as Earth got booted out of the solar system, taking with it a clutch of Kuiper Belt objects into far more distant orbits.

That renegade planet could have left the solar system – or may still be in orbit today.

Astronomers suspect several Earth-mass sized planets formed in the giant planets region.

“What happened to those objects – if they collided with the giant planets and eventually became a part of the giant planets, or if they got ejected – is not known,” astronomer Scott Sheppard, with the Carnegie Institution of Washington DC, told Discovery News.

Some computer models show it was another giant planet that got expelled from the solar system, pulling bodies as it went.

“The bigger the object, the more planets it could pull out to this region,” Sheppard said.

The search for other Sedna-like objects continues. Sheppard and colleague Chad Trujillo with the Gemini Observatory in Hawaii, are working this week to try to confirm six more potential objects discovered last year.

Several observations over a period of at least a year are needed to detect the slight motion of the small, dim targets against background stars.

Read more at Discovery News

First Asteroid Found Sporting a Ring System

When you think of a celestial ring system, the beautiful ringed planet Saturn will likely jump to mind. But for the first time astronomers have discovered that ring systems aren’t exclusive to planetary bodies — asteroids can have them too.

Announced on Wednesday, astronomers using several observatories in South America, including the ESO’s La Silla Observatory in Chile, have discovered that distant asteroid Chariklo possesses two distinct rings. Chariklo, which is approximately 250 kilometers (155 miles) wide, is the largest space rock in a class of asteroids known as Centaurs that orbit between Saturn and Uranus in the outer solar system.

“We weren’t looking for a ring and didn’t think small bodies like Chariklo had them at all, so the discovery — and the amazing amount of detail we saw in the system — came as a complete surprise!” said lead researcher Felipe Braga-Ribas, of the Observatório Nacional and MCTI, in Rio de Janeiro, Brazil.

Due to the asteroid’s remote location, direct observations of Chariklo’s rings are not possible. Instead, astronomers planned to watch the asteroid drift in front of a distant star — an event known as an occultation, when starlight is blocked for a few seconds. As the asteroid drifted in front of the star UCAC4 248-108672 on June 3, 2013, the astronomers noticed something strange happen to the starlight a few seconds before and a few seconds after occultation: there was a double-dip in starlight brightness.

Astronomers have interpreted this double-dip signal as the presence of a double ring system — the first ever ring system discovered around an asteroid.

“For me, it was quite amazing to realize that we were able not only to detect a ring system, but also pinpoint that it consists of two clearly distinct rings,” said team member Uffe Gråe Jørgensen of the Niels Bohr Institute, University of Copenhagen, Denmark. “I try to imagine how it would be to stand on the surface of this icy object — small enough that a fast sports car could reach escape velocity and drive off into space — and stare up at a 20-kilometre wide ring system 1000 times closer than the moon.”

The astronomers have been able to read incredible details from this observation, including information about the ring system’s shape, orientation and width. There are two sharply confined rings 7 kilometers (4.3 miles) and 3 kilometers (1.9 miles) wide separated by a 9 kilometer (5.6 miles) gap. The rings are being nicknamed Oiapoque and Chuí, two rivers in Brazil.

The ring gap and the ring system’s defined shape is suggestive of the presence of a small satellite in orbit around the asteroid.

“So, as well as the rings, it’s likely that Chariklo has at least one small moon still waiting to be discovered,” said Braga-Ribas.

Read more at Discovery News

Mar 25, 2014

Paleontologists assemble giant turtle bone from fossil discoveries made centuries apart

"As soon as those two halves came together, like puzzle pieces, you knew it," said Ted Daeschler, PhD, associate curator of vertebrate zoology and vice president for collections at the Academy of Natural Sciences of Drexel University.

That surprising puzzle assembly occurred in the fall of 2012, when Jason Schein, assistant curator of natural history at the New Jersey State Museum, visited the Academy's research collections to better identify and describe a recently-unearthed fossil. The discovery linked scientists from both museums to their predecessors from the 19th century, while setting the stage to advance science today.

The partial fossil bone that Schein had brought to the Academy was a recent discovery by amateur paleontologist Gregory Harpel. Harpel thought the bone seemed strange and out of place when he noticed it on a grassy embankment, a bit upstream from his usual fossil-hunting haunt at a brook in Monmouth County, N.J. Visiting the brook to search for fossil shark teeth is a weekend hobby for Harpel, an analytical chemist from Oreland, Pa. "I picked it up and thought it was a rock at first -- it was heavy," Harpel said.

When he realized it was indeed a fossil, certainly much larger and possibly a lot more scientifically significant than shark teeth, he took it to the experts at the New Jersey State Museum, to which he ultimately donated his find.

Schein and David Parris, the museum's curator of natural history, immediately recognized the fossil as a humerus -- the large upper arm bone -- from a turtle, but its shaft was broken so that only the distal end, or end nearest to the elbow, remained.

Parris also thought the fossil looked extremely familiar. He joked with Schein that perhaps it was the missing half of a different large, partial turtle limb housed in the collections at the Academy of Natural Sciences of Drexel University. That bone also had a broken shaft, but only its proximal end, nearest to the shoulder, remained. The coincidence was striking.

"I didn't think there was any chance in the world they would actually fit," Schein said.

That's because the Academy's piece of the puzzle was much too old, according to the conventional wisdom of paleontology. Paleontologists expect that fossils found in exposed strata of rock will break down from exposure to the elements if they aren't collected and preserved, at least within a few years-- decades at the most. There was no reason to think a lost half of the same old bone would survive, intact and exposed, in a New Jersey streambed from at least the time of the old bone's first scientific description in 1849, until Harpel found it in 2012.

The Academy's older bone was also without a match of any kind, making a perfect match seem even more farfetched: It was originally named and described by famed 19th-century naturalist Louis Agassiz as the first, or type specimen, of its genus and species, Atlantochelys mortoni. In the intervening years, it remained the only known fossil specimen from that genus and species.

It remained so until that fateful day when Schein carried the "new" New Jersey fossil to the Academy in Philadelphia, connecting the two halves. The perfect fit between the fossils left little space for doubt. Stunned by the implications, Schein and Academy paleontology staffers Jason Poole and Ned Gilmore, who had assembled the puzzle together, called Daeschler into the room.

"Sure enough, you have two halves of the same bone, the same individual of this giant sea turtle," said Daeschler. "One half was collected at least 162 years before the other half."

Now, the scientists are revising their conventional wisdom to say that, sometimes, exposed fossils can survive longer than previously thought. They report their remarkable discovery in the forthcoming 2014 issue of the Proceedings of the Academy of Natural Sciences of Philadelphia.

"The astounding confluence of events that had to have happened for this to be true is just unbelievable, and probably completely unprecedented in paleontology," said Schein.

The fully assembled A. mortoni humerus now gives the scientists more information about the massive sea turtle it came from as well. With a complete limb, they have calculated the animal's overall size -- about 10 feet from tip to tail, making it one of the largest sea turtles ever known. The species may have resembled modern loggerhead turtles, but was much larger than any sea turtle species alive today.

Read more at Discovery News

Exploding stars prove Newton's law of gravity unchanged over cosmic time

Australian astronomers have combined all observations of supernovae ever made to determine that the strength of gravity has remained unchanged over the last nine billion years.

Newton's gravitational constant, known as G, describes the attractive force between two objects, together with the separation between them and their masses. It has been previously suggested that G could have been slowly changing over the 13.8 billion years since the Big Bang.

If G has been decreasing over time, for example, this would mean that Earth's distance to the Sun was slightly larger in the past, meaning that we would experience longer seasons now compared to much earlier points in Earth's history.

But researchers at Swinburne University of Technology in Melbourne have now analysed the light given off by 580 supernova explosions in the nearby and far Universe and have shown that the strength of gravity has not changed.

"Looking back in cosmic time to find out how the laws of physics may have changed is not new" Swinburne Professor Jeremy Mould said. "But supernova cosmology now allows us to do this with gravity."

A Type 1a supernova marks the violent death of a star called a white dwarf, which is as massive as our Sun but packed into a ball the size of our Earth.

Our telescopes can detect the light from this explosion and use its brightness as a 'standard candle' to measure distances in the Universe, a tool that helped Australian astronomer Professor Brian Schmidt in his 2011 Nobel Prize winning work, discovering the mysterious force Dark Energy.

Professor Mould and his PhD student Syed Uddin at the Swinburne Centre for Astrophysics and Supercomputing and the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) assumed that these supernova explosions happen when a white dwarf reaches a critical mass or after colliding with other stars to 'tip it over the edge'.

"This critical mass depends on Newton's gravitational constant G and allows us to monitor it over billions of years of cosmic time -- instead of only decades, as was the case in previous studies," Professor Mould said.

Despite these vastly different time spans, their results agree with findings from the Lunar Laser Ranging Experiment that has been measuring the distance between Earth and the Moon since NASA's Apollo missions in the 1960s and has been able to monitor possible variations in G at very high precision.

"Our cosmological analysis complements experimental efforts to describe and constrain the laws of physics in a new way and over cosmic time." Mr Uddin said.

In their current publication, the Swinburne researchers were able to set an upper limit on the change in Newton's gravitational constant of 1 part in 10 billion per year over the past nine billion years.

Read more at Science Daily

How a Giant Sunflower Will Help Us See Alien Worlds

It seems that announcements of newly-discovered exoplanets are occurring on an almost weekly basis these days — 961 confirmed, at last count — but the hunt continues for a truly Earth-like world. And even with 20 exoplanets categorized as “potentially habitable,” the real determination of their capability to harbor life as we know it will only come with investigation of their atmospheres, a tricky task considering the inherent proximity of habitable worlds to their host stars.

When you realize that the sun’s diameter is 109 times that of Earth’s, you can imagine how difficult it would be to spot our own life-covered planet from even a moderate cosmic distance.

That’s where NASA’s starshade comes in. Like an enormous origami sunflower, the starshade would work in tandem with a space-based telescope to block the glare from target stars, allowing their planets to be observed directly and their atmospheres studied in intricate detail.

The secret is in the starshade’s “petals,” which, once unfurled to their full 34-meter diameter, are specifically designed to reduce the bending of light around the edges.

“Less light bending means that the starshade shadow is very dark, so the telescope can take images of the planets without being overwhelmed by starlight,” said Dr. Stuart Shaklan, lead engineer on the starshade project at NASA’s Jet Propulsion Laboratory.

Watch a video of the starshade in action and in development below:

Launched along with a space telescope, the starshade would then use an onboard propulsion system to position itself ahead of the telescope and between observation targets. Alternatively it could also be used with existing telescopes, like the upcoming James Webb Space Telescope, slated for launch in 2018.

It may just be that “flower power” is what NASA needs to spot Earth’s true twin.

Read more at Discovery News

Lasers to Solve the Black Hole Information Paradox?

In an effort to help solve the black hole information paradox that has immersed theoretical physics in an ocean of soul searching for the past two years, two researchers have thrown their hats into the ring with a novel solution: Lasers.

Yes, lasers.

So what the heck have lasers got to do with black holes? Technically, we’re not talking about the little flashy devices you use to keep your cat entertained, we’re talking about the underlying physics that produces laser light and applying it to information that falls into a black hole.

Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. In its simplest form, laser light is generated inside a cavity where a photon will interact with a material, simulating it and amplifying the output. The process cascades to generate a beam of collimated and coherent light that is very useful for communications, industry and entertainment.

“Basically, it works like a copy machine: you throw something into the machine, and two identical somethings come out,” said Chris Adami, a physics professor at Michigan State University. If you apply this mechanism to an event horizon as matter falls into a black hole, according to Adami, we may have some kind of solution to the black hole “firewall paradox.”

Adami co-wrote a paper based on this research with Greg Ver Steeg of University of Southern California, Los Angeles, that was published in the April 7 edition of the journal Classical and Quantum Gravity.

The firewall is an uneasy solution to decades of debate in the physics world around information falling into a black hole.

In the 1970s, renowned black hole physicist Stephen Hawking made the realization that black holes aren’t totally black. Taking his cue from quantum physics, pairs of virtual particles are predicted to pop into existence, annihilate with each other and then disappear. But right at the edge of an event horizon — the point at which spacetime warping around a black hole is so extreme even light cannot escape the black hole’s grasp — one of these virtual particles may become trapped and pulled away from being annihilated by its partner, making the escaping particle “real,” leaching a tiny amount of mass from the black hole.

This slight “evaporation” of mass became known as Hawking radiation and completely revolutionized our perspective on black holes — depending on their mass, they will evaporate and eventually disappear. Black holes aren’t as permanent we once thought.

The formulation of Hawking radiation heralded the beginning of some hefty theoretical hurt and it all boiled down to how black holes deal with information. The information contained within the matter falling into a black hole is ultimately destroyed by its total evaporation out of existence — a scenario that violates our physical understanding of how the universe works. Is information really being destroyed or is it somehow being conserved in a way don’t yet understand?

A recent development to the last few decades of debate (involving Hawking and other key physicists) came in 2012 when physicists led by Joseph Polchinski of the University of California in Santa Barbara published their research on the information paradox. If indeed black holes do not destroy information, there must be a raging inferno just inside the black hole’s event horizon called a “firewall.”

Earlier this year, Hawking stepped in arguing that the firewall is not needed and advocated a “chaos wall” that instead jumbles up the information (thereby not violating quantum rules) and varies the location of the event horizon depending on the information that is falling in. In this scenario, argued Hawking, an event horizon (in its classical sense) does not exist — it should be replaced by an “apparent horizon.”

This certainly isn’t a “win” for Hawking or anyone else, it’s just another idea that has been thrown into the pot in an effort to find some balance between apparently conflicting theories that govern information getting consumed by a black hole.

But say if this whole thing has been overcomplicated? Perhaps a mechanism has been overlooked? This is where Adami’s stimulated emission of radiation idea comes in.

“If you throw information at a black hole, just before it is swallowed, the black hole first makes a copy that is left outside. This copying mechanism was discovered by Albert Einstein in 1917, and without it, physics cannot be consistent,” said Adami in a news release.

“In my view Chris Adami has correctly identified the solution to the so-called black hole information paradox,” said Paul Davies, theoretical physicist at Arizona State University. “Ironically, it has been hiding in plain sight for years.”

As matter falls into a black hole’s event horizon, Adami thinks radiation is generated via stimulated emission, retaining a copy of the in-falling information. This radiation will be distinct from the spontaneous Hawking radiation also being generated.

“Stimulated emission of radiation is precisely the process of copying information: one particle comes in, two leave with the same exact set of quantum numbers,” write Adami and Ver Steeg in their publication.

However, information cannot be copied perfectly in the quantum world (a concept known as the no-cloning theorem), “but it turns out that the spontaneous emission of radiation (the Hawking radiation of the black hole) conveniently prevents perfect cloning by supplying the necessary minimum amount of noise.”

The researchers state that this research doesn’t directly address the information that falls beyond the black hole’s event horizon, however, as stimulated emission would occur at the boundary of the black hole’s event horizon, but it could be a potential answer to the information paradox.

Read more at Discovery News

Mar 24, 2014

DNA from fossils reveal origin of Norwegian lemmings

A new ancient DNA study shows that the Norwegian lemming has a unique history. In contrast to other mammals in Fennoscandia, the Norwegian lemming may have survived the last Ice Age in the far north, sealed off from the rest of the world by gigantic ice sheets. This conclusion is drawn by an international team of researchers in an article published this week in the journal Molecular Ecology.

The Norwegian lemming is an iconic small mammal that is unique to the Fennoscandian mountain tundra. Known for its dramatic fluctuations in population size, it is a keystone species in the mountain tundra ecosystem. But its origin has until now remained somewhat of a mystery.

Twenty thousand years ago, Fennoscandia was covered by a thick ice sheet. Animals and plants in the region are therefore thought to originate from populations that lived to the south or east of the ice sheet, and colonised Fennoscandia as the ice melted. With this in mind, and international team of scientists, led by researchers at the Swedish Museum of Natural History, set out to investigate from where the Norwegian lemming originated at the end of the last Ice Age. To do this, the researchers retrieved and analysed ancient DNA from lemming populations that surrounded the ice sheet during the last Ice Age.

- "We found that even though the populations surrounding the ice sheet were closely related to modern day lemmings, none of them were similar enough to be the direct ancestor of the Norwegian lemming," says Love Dalén, Associate Professor at the Swedish Museum of Natural History.

Read more at Science Daily

When Did Earth's First Whiffs of Oxygen Emerge?

Today's climate change doesn't hold a candle to the chemical warfare waged on Earth more than 2 billion years ago.

Before plants discovered the power of photosynthesis, single-celled life survived on chemicals, not sunlight, burning through hydrogen, methane and sulfur, among other yummy compounds. These "anaerobes" that live without oxygen were poisoned when blue-green algae called cyanobacteria evolved photosynthesis and started exhaling oxygen. The highly reactive gas combines with metals and proteins in anaerobic cells, killing them. But cyanobacteria thrived, turning sunlight into sugar and excreting oxygen as waste.

Oxygen levels in rocks suddenly rise starting 2.5 billion years ago — a spike called the "Great Oxidation Event." The jump was long held up as evidence for when cyanobacteria evolved photosynthesis. But a study published today (March 23) in the journal Nature Geoscience joins a growing body of data that suggests the earliest sun-lovers appeared long before this oxygen spike.

Many researchers now think the first photosynthetic organisms lived on Earth 3 billion years ago. And like art restorers who find a hidden image under an Old Master painting, these scientists are discovering a new picture of Earth's first breath.

Heavy metals

In the new study, Yale University geochemist Noah Planavsky and his colleagues analyzed levels of molybdenum and iron in 2.95-billion-year-old rocks from South Africa. The rocks were laid down in water, in a shallow ocean setting near the shore. The metals serve as markers of photosynthesis. Molybdenum isotopes, or elements with the same number of protons but a different number of neutrons, track manganese oxidization, a process that requires high levels of oxygen, Planavsky said.

The chemical traces in the rocks, from the Pongola Supergroup, indicate cyanobacteria were producing oxygen in ocean surface water, Planavsky said. "Our study is telling you that there was localized cyanobacteria production in the oceans," he told Live Science's Our Amazing Planet.

In another recent study, also on South Africa's Pongola rocks, scientists looked at chromium isotopes to estimate atmospheric oxygen levels 3 billion years ago. The results suggest atmospheric oxygen was about 100,000 times higher than could be explained by non-biological chemical reactions, according to the research, published Sept. 26, 2013, in the journal Nature.

"The two studies are quite complementary," Planavsky said. "We're providing independent evidence of the presence of cyanobacteria. We're tracking surface ocean processes and they're tracking terrestrial processes."

However, Woodward Fischer, a geobiologist at Caltech in Pasadena, Calif., cautions that the trace metal techniques need further validation. Both analytic methods are just about a decade old and are being tested in extremely old rocks. "The quality of our interpretations derived from them remains a little bit uncertain," said Fischer, who was not involved in either study. "In all fairness, we don't understand the molybdenum and the chromium cycle today."

Which came first?

As more sensitive techniques emerge for peering into deep time, a new debate has surfaced: Did microbes pump our planet's first breath, or did environmental changes push the planet into oxygen richness?

Emerging evidence suggests oxygen levels took a roller coaster ride in the 500 million years between when the first cyanobacteria evolved photosynthesis and the Great Oxidation Event. That's a long time for life — it's about the same as the time between Earth's first trilobites and humans.

Read more at Discovery News

What Is Ebola?

The Ebola virus, which has caused various outbreaks in Africa since it was first identified in 1976, is one of the deadliest viruses known.

Causing severe bleeding and organ failure, most of the sub-types of the virus kill in 25-90 percent of the people they infect. There are no approved drugs to treat the disease.

Humans contract Ebola from animals, often from eating infected meat or contact with bat feces or urine. Once one person gets it, it can be spread through body fluids, contaminated needles, and body tissue. The contagious period usually starts after symptoms appear. New infections often occur when family members take care of each other and prepare dead bodies for burial, according to The Mayo Clinic.

Symptoms, which usually come on quickly, include fever, headache, aches, chills and sore throat, and progress to nausea and vomiting, diarrhea, rash, chest pain and cough, weight loss and bleeding.

In lieu of medication, people are sometimes quarantined to curtail an outbreak.

“Isolation units are essential to prevent the spread of the disease, which is highly contagious,” Dr. Esther Sterk, medicine adviser of the international medical charity Medecins Sans Frontieres, said in a statement.

From Discovery News

Ebola Said to Be Source of Mysterious, Deadly Epidemic

Guinea identified the Ebola virus Saturday as the source of a highly contagious epidemic raging through its southern forests, as the death toll rose to 59.

Experts in the west African nation had been unable to identify the disease, whose symptoms -- diarrhea, vomiting and bleeding -- were first observed six weeks ago, but scientists studying samples in the French city of Lyon confirmed it was Ebola, the Guinean health ministry said.

"The Ebola fever epidemic raging in southern Guinea, including the prefectures of Gueckedou and Macenta, since February 9 has left at least 59 dead out of 80 cases identified by our services on the ground," said Sakoba Keita, the ministry's chief disease prevention officer.

"We are overwhelmed in the field, we are fighting against this epidemic with all the means we have at out disposal with the help of our partners but it is difficult. But we will get there," he said.

To date, no treatment or vaccine is available for Ebola, which kills between 25 and 90 percent of those who fall sick, depending on the strain of the virus, according to the World Health Organization.

The disease is transmitted by direct contact with blood, feces or sweat, or by sexual contact or unprotected handling of contaminated corpses.

Medical aid group Doctors Without Borders (MSF) said in a statement it would strengthen its team of 24 doctors, nurses, logisticians and experts in hygiene and sanitation already in Guinea.

The organization has set up isolation units for suspected cases in the southern region of Nzerekore and is looking for people who may have had contact with the infected.

"These structures are essential to prevent the spread of the disease, which is highly contagious," said MSF tropical medicine adviser Esther Sterk said.

"Specialized staff are providing care to patients showing signs of infection."

MSF said it was sending around 33 tonnes of medicines and isolation, sanitation and protective equipment in two planes leaving from Belgium and France.

Ebola, one of the world's most virulent diseases, was first discovered in the Democratic Republic of Congo (DRC) in 1976 and the country has had eight outbreaks.

The most recent epidemic, in the DRC, infected 62 people and left 34 dead between May and November 2012, according to the country's health ministry.

There are fears it could be used in a biological weapons attack.

According to researchers, the virus multiplies quickly, overwhelming the immune system's ability to fight the infection.

The French embassy in the Liberian capital Monrovia released a travel advisory warning French citizens against travel to the affected parts of Guinea or areas of northern Liberia near the border between the countries.

Read more at Discovery News

Falling Into the Guts of a Black Hole

If you happened to be falling into a black hole, the last thing on your mind will likely be how pretty the view is. But in this NASA Astronomy Picture of the Day, some idea about the dynamic swirl of awesome energy just outside a black hole’s event horizon (or is that an apparent horizon?) has been created in a computer simulation meaning we can enjoy the physics prettiness from a very safe distance.

This simulation, created by the NASA Chandra X-ray Observatory team, shows the detail of matter spinning into a stellar mass black hole. The matter, which has collected in a hot accretion disk, falls toward the black hole’s event horizon — the distance at which the black hole’s spacetime warping is so intense that even light cannot escape. Some of the matter passes through the horizon, adding to the black hole’s bulk, but the rest is redirected via intense magnetic fields, ejecting it from the poles at relativistic speeds.

As seen in the simulation, the polar jets can be seen being ejected from the black hole’s spin axis. Missions such as Chandra are able to observe these jets as they generate powerful X-ray radiation. Radio wave signatures can also be observed, aiding our understanding of how these energetic beasts work.

As noted by NASA, by studying the radiation generated by black hole GRO J1655-40, an unusual flickering at a rate of 450 times a second has been detected. This flickering has been attributed to the rapid spin of the black hole, which is estimated to be 7 times the mass of our sun. The mechanisms behind the flickering are the focus of intense research, but it seems likely that we won’t fully understand the black hole accretion disk interplay until we can directly image the black hole’s event horizon, a feat that may be possible in the not-so-distant future.

From Discovery News