Jun 29, 2013

Social Networks Shape Monkey 'Culture' Too

Of course Twitter and Facebook are all the rage, but the power of social networks didn't start just in the digital age. A new study on squirrel monkeys reported in Current Biology, a Cell Press publication, on June 27 finds that monkeys with the strongest social networks catch on fastest to the latest in foraging crazes. They are monkey trendsters.

The researchers, led by Andrew Whiten of the University of St Andrews, made the discovery by combining social network analysis with more traditional social learning experiments. By bringing the two together, they offer what they say is the first demonstration of how social networks may shape the spread of new cultural techniques. It's an approach they hope to see adopted in studies of other social animals.

"Our study shows that innovations do not just spread randomly in primate groups but, as in humans, are shaped by the monkeys' social networks," Whiten said.

Whiten, along with Nicolas Claidière, Emily Messer, and William Hoppitt, traced the monkeys' social networks by recording which monkeys spent time together in the vicinity of "artificial fruits" that could be manipulated to extract tempting food rewards. Sophisticated statistical analysis of those data revealed the monkeys' social networks, with some individuals situated at the heart of the network and others more on the outside. The researchers rated each of the monkeys on their "centrality," or social status in the network, with the highest ratings going to monkeys with the most connections to other well-connected individuals.

The artificial fruits could be opened in two different ways, either by lifting a little hatch on the front or by pivoting it from side to side. The researchers trained the alpha male in one group of monkeys on the lift technique, while the leader in another group was trained on the pivot method. They then sent them back to their groups and watched to see how those two methods would catch on in the two groups.

More central monkeys with the strongest social ties picked up the new methods more successfully, the researchers found. They were also more likely than peripheral monkeys to learn the method demonstrated by their trained alpha leaders.

Whiten said the squirrel monkeys are a good species for these studies because of their natural inquisitiveness. They also lead rather intense social lives.

The researchers now hope to extend their studies to focus on the squirrel monkeys in different contexts -- while foraging, moving, and resting, for example -- and how those contexts might influence the spread of innovations. They suspect they might even find evidence for different monkey subcultures.

Read more at Science Daily

How Earth Heals Itself After an Earthquake

For the first time, scientists have watched the Earth heal itself after an earthquake.

The process is similar to the body repairing a cut, researchers from China and the United States reported this week in the journal Science. During an earthquake, the ground tears apart along a fault, leaving a jagged series of fractures. After China's devastating magnitude 7.9 Wenchuan earthquake in 2008, fluids filled the fractured fault, like blood gushing into a wound, the team found by drilling into the fault.

Within two years — a blink of the eye in geologic time — the fault was speedily knitting itself back together, closing gaps through a combination of processes. But the gashes occasionally reopened when damaged by shaking from distant earthquakes, the study reports.

No one knows for sure how faults heal, and the observations from the Wenchuan drilling project offer more questions than answers. But the project's long-term monitoring of fractures opening and closing on a fault offers a series of fascinating puzzles for scientists to solve, said Chris Marone, a geophysicist at Penn State University who was not involved in the study.

"These are new observations. Unraveling exactly what's going on here could have serious implications for a lot of really important technical things," Marone said. Models based on the results could impact any place where water flows underground, such as in faults or aquifers or wells, he said.

Rapid response drilling

The Wenchuan project team tracked the healing process through a series of deep boreholes drilled through the fault. The study is part of an ongoing global effort to examine faults immediately after earthquakes, in hopes of checking the results of decades of laboratory experiments and computer modeling.

"We already know there are a lot of reasons real faults may not behave the way we think they do," said Emily Brodsky, a study co-author and geophysicist at the University of California, Santa Cruz. "If we're going to gain some actual new insights or go well beyond where our imaginations went before, we need the real deal," she said.

The Chinese-sponsored Wenchuan earthquake Fault Scientific Drilling project began 178 days after the May 12, 2008, earthquake. The massive temblor killed more than 80,000 people. Five boreholes pierced through the messy fault zone, finding 0.4 inches (1 centimeter) of fresh fault gouge, a type of pulverized rock.

For 18 months, the team monitored the fault's permeability, a measure of how quickly water flows through the rock. Permeability is a stand-in for damage on the fault, Brodsky said — as the fault heals, the area should become less permeable to fluids. The experiment tracked the ebb and flow of fault fluids from tidal forces, the same tugs from the sun and moon that create ocean tides.

The researchers saw a steady decrease in permeability at the boreholes. As the gaps and fractures along the fault zone filled in with new minerals deposited by the fluids, or squeezed shut, the permeability drops, the researchers think.

The overall permeability drop was significantly faster than predicted by laboratory experiments, Brodsky told LiveScience's OurAmazingPlanet. The likely reason is rapid fault healing, but Brodsky said she doesn't have a good explanation for how that happens yet. "I don't know why it's faster," she said. "This sort of begs us to work out the process."

Remote triggering
But they did solve another puzzle: Six short-term jumps in the permeability, random events with no link to local aftershocks or equipment problems. The team eventually realized shaking from big but distant earthquakes broke open healed sections of the fault, Brodsky said. Some of the remote culprits include the March 2011 Japan earthquake and a magnitude-7.8 earthquake in Sumatra in April 2010.

"We expected to see some sort of healing effect, but we did not expect to see this re-damaging effect, so that was sort of a surprise," Brodsky said. "This interplay is a much more complicated process than we anticipated seeing."

Read more at Discovery News

Jun 28, 2013

How 'Parrot Dinosaur' Switched from Four Feet to Two as It Grew

Tracking the growth of dinosaurs and how they changed as they grew is difficult. Using a combination of biomechanical analysis and bone histology, palaeontologists from Beijing, Bristol, and Bonn have shown how one of the best-known dinosaurs switched from four feet to two as it grew.

Psittacosaurus, the 'parrot dinosaur' is known from more than 1000 specimens from the Cretaceous, 100 million years ago, of China and other parts of east Asia. As part of his PhD thesis at the University of Bristol, Qi Zhao, now on the staff of the Institute for Vertebrate Paleontology in Beijing, carried out the intricate study on bones of babies, juveniles and adults.

Dr Zhao said: "Some of the bones from baby Psittacosaurus were only a few millimetres across, so I had to handle them extremely carefully to be able to make useful bone sections. I also had to be sure to cause as little damage to these valuable specimens as possible."

With special permission from the Beijing Institute, Zhao sectioned two arm and two leg bones from 16 individual dinosaurs, ranging in age from less than one year to 10 years old, or fully-grown. He did the intricate sectioning work in a special palaeohistology laboratory in Bonn, Germany,

The one-year-olds had long arms and short legs, and scuttled about on all fours soon after hatching. The bone sections showed that the arm bones were growing fastest when the animals were ages one to three years. Then, from four to six years, arm growth slowed down, and the leg bones showed a massive growth spurt, meaning they ended up twice as long as the arms, necessary for an animal that stood up on its hind legs as an adult.

Professor Xing Xu of the Beijing Institute, one of Dr Zhao's thesis supervisors, said: "This remarkable study, the first of its kind, shows how much information is locked in the bones of dinosaurs. We are delighted the study worked so well, and see many ways to use the new methods to understand even more about the astonishing lives of the dinosaurs."

Professor Mike Benton of the University of Bristol, Dr Zhao's other PhD supervisor, said: "These kinds of studies can also throw light on the evolution of a dinosaur like Psittacosaurus. Having four-legged babies and juveniles suggests that at some time in their ancestry, both juveniles and adults were also four-legged, and Psittacosaurus and dinosaurs in general became secondarily bipedal."

The paper is published in Nature Communications.

From Science Daily

Evidence of 2000-Year-Old Famine Found in Jerusalem

Three intact cooking pots and a small ceramic oil lamp have provided Israeli archaeologists with the first evidence for the famine and terror that spread throughout Jerusalem during the Roman siege nearly 2,000 years ago.

The items belonged to Jewish residents who took shelter in the underground water channel. They were found in a cistern near the Western Wall, not far from Robinson’s Arch in the Jerusalem Archaeological Park.

According to Eli Shukron, excavation director at the Israel Antiquities Authority (IAA), people went down into the cistern to secretly eat the food that was contained in the pots, hiding from the Roman soldiers and the Jewish rebels who would have tried to take away the frugal meal.

“This is the first time we are able to connect archaeological finds with the famine that occurred during the siege of Jerusalem at the time of the Great Revolt,” Shukron said in a statement.

Beginning in 66 A.D., the Great Revolt was the first of several Jewish rebellions against the Roman rule.

Despite remarkable resistance, the Jewish people were ultimately crushed. In 70 A.D., the Romans under Titus sacked the city and destroyed the second Temple, which, according to Jewish tradition, was built by King Herod the Great on the site of King Solomon’s temple. This was razed by the Babylonians around 587 B.C.

The Romans plundered tons of gold, silver trumpets and gold candelabra from Herod’s magnificent white and gold temple. Then they paraded the treasure, which also helped finance the building of the Colosseum, through the streets of Rome in triumph.

The new finding, said Shukrun, matches the vivid account of the historian Titus Flavius Josephus (37 – about 100). He reported the dramatic events and widespread starvation in Jerusalem, claiming that 1,100,000 people, mainly Jewish, were killed during the siege.

In his dramatic description of the famine, the historian recounted that Jewish rebels sought food in the homes of their fellow Jews. They concealed and ate whatever they had in hidden places in their homes.

“For as nowhere was there corn to be seen, men broke into the houses and ransacked them,” Josephus wrote in his book “The Jewish War.”

“If they found some, they maltreated the occupants for saying there was none; if they did not, they suspected them of having hidden it more carefully and tortured them,” he added.

Read more at Discovery News

Cave Art Reveals Ancient View of Cosmos

Some of the oldest art in the United States maps humanity's place in the cosmos, as aligned with an ancient religion.

A team of scientists has uncovered a series of engravings and drawings strategically placed in open air and within caves by prehistoric groups of Native American settlers that depict their cosmological understanding of the world around them.

"The subject matter of this artwork, what they were drawing pictures of, we knew all along was mythological, cosmological," Jan Simek, an archaeologist at the University of Tennessee said. "They draw pictures of bird men that are important characters in their origin stories and in their hero legends, and so we knew it was a religious thing and because of that, we knew that it potentially referred to this multitiered universe that was the foundation of their cosmology."

Simek and his team studied art from 44 open-air locations and 50 cave sites. The earliest depiction of this kind of cosmological stratification dates to around 6,000 years ago, but most of the art is more recent, from around the 11th to 17th centuries.

The researchers noticed that certain kinds of drawings and engravings only appear in specific areas of the plateau. For instance, open-air spots in high elevations touched by the sun feature "upper world" artistic renderings that include depictions of weather forces, heavenly bodies and characters that can exert influence on humans.

"Lower world" drawings and engravings are found in dark areas like caves that are hidden from the sun. Usually, this layer of the world is associated with death, darkness and danger.

The "middle world" is representative of the reality that surrounded prehistoric humans on a daily basis. These drawings were found in both open-air environments and caves, but for the most part, they were found in the middle elevations of the plateau.

"This layered universe was a stage for a variety of actors that included heroes, monsters and creatures that could cross between the levels," Simek said in a statement.

Although depictions of many of the actors were found in low, high and middle elevations, color relates the overall cosmological structure of the universe, Simek said. Characters drawn in red — the color of life — are found in higher elevation sites, while black was used to draw figures found in the lower world.

"The dominant things we see all together are human images, what we call anthropomorphs," Simek told LiveScience. "They're not all human; some of them are clearly mythological people or people who blend animal and human characteristics."

Read more at Discovery News

New Hooter From the Past Found Fossilized

Scientists have found a new fossil of an owl species that lived 2,000 years ago in the remote São Miguel Island off Portugal. It was likely wiped out by the arrival of human settlers in the archipelago in the 1400s.

Scientists were digging in a cave near the volcano Água de pau when they found the bones of the bird. They put the bones together like a jigsaw to figure out what the bird must have looked like.

The species, christened the São Miguel scops owl (Otus frutuosoi), adds a new species to the Otus family of owls, commonly known as scops owls. The tarsi bones of the São Miguel scops, its stick-like connections between the thighs and feet, were weak. Coupled with short wings, the owls were likely not great fliers, but rather lived on the floor of the island’s laurel forests eating insects. The work was published in the journal Zootaxa.

It was possible for the birds to live on or close to the ground because there would have been few predators on the island 2,000 years ago.

The São Miguel Island is part of the Azores Islands archipelago, located about 900 miles west of Portugal. These are volcanic islands that jut out of the ocean floor at the tectonic triple juncture where the North American Plate separates from the Eurasian Plate and the African Plate along the mid-Atlantic ridge.

At the beginning, São Miguel Island was nothing more than rock.

Over time, a very few plants, insects and birds would have crossed the ocean by chance and stumbled onto the Azores. And they would have found it difficult to fly back, given the vast ocean separating the island from the main land. The immigrant birds would have instead adapted to their new home. Over time, they would occupy niches and evolve into new species of birds unique to the island – such as a flightless owl species that feeds on insects.

Given its remoteness and size, the Azores Islands should have many endemic bird species, but it has only two. Compare that against the Madeira Islands, which has four, the Canary Islands, which has five endemic bird species, and Cape Verde which has six. Scientists have suggested that the Azores had more species that then died out.

The São Miguel scops owl, which is the first fossil discovered on the island of an extinct bird species, suggests this might be true.

The trigger of extinction is likely to be humans, the scientists suggest. That’s not an unreasonable claim given that most volcanic islands witnessed rapid extinctions once mariners took to the oceans.

Mariners settled on the Azores Islands in the 15th-century. The impact of their arrival can be indirectly surmised by examining the historical record of the nearby Canary and Madeira Islands. There, human settlers caused extinctions of a number of bird species, by hunting, introducing new species that would compete for resources, and by changing ecosystems.

Read more at Discovery News

Jun 27, 2013

Ancient African Coins Spark Treasure Hunt

Can a handful of ancient African coins, discovered almost 70 years ago by a lone soldier on a remote island, rewrite history?

A weathered, hand-drawn map, with an "X" marking the spot on the Australian island where the African coins were discovered, might help an international team of researchers, who will travel to the island this summer, answer that question.

The story begins over a thousand years ago, when the city of Kilwa was the richest trading center on the eastern coast of Africa.

A bustling harbor, a glittering mosque decorated with Chinese porcelain and the Husuni Kubwa palace (famed for its octagonal swimming pool) made Kilwa a premier destination for wealthy merchants, who traded African gold and ivorty for spices and perfume from the Far East.

A dazzling era ends

But the city's eminence ended when Portuguese traders, intent on controlling commerce throughout the Indian Ocean, sacked the port in the 16th century.

"The Portuguese destroyed Kilwa in the 1500s, burnt it to the ground and looted everything," Ian McIntosh, a professor of anthropology at Indiana University-Purdue University Indianapolis (IUPUI), told Australian broadcaster ABC.

The deserted, crumbling ruins of Kilwa — now a UNESCO World Heritage site located near Zanzibar in modern-day Tanzania — are all that remains of the city's former splendor.

A handful of coins

Centuries later and thousands of miles away, an Australian soldier named Maurie Isenberg was operating a World War II radar station on one of the uninhabited Wessel Islands off Australia's northern shore, CNN reports.

One day, during his off-hours, Isenberg went fishing down at the remote island's beach, where he discovered a few old, copper coins with exotic markings embedded in the sand. Isenberg tossed the coins in a tin container, where they stayed for decades.

But before he forgot about his discovery, on a map of the island hand-drawn by a fellow soldier, Isenberg drew an "X" showing where he found the coins.

In 1979, Isenberg sent the coins off for appraisal. He was astonished to discover their origin: Four of the coins were from the Dutch East India Company -- a trading company founded by the Dutch in the early 17th century -- and one of those coins dated from the late 1600s, according to CNN.

But five of the coins were minted in Kilwa and are believed to be about 1,100 to 1,200 years old (from about A.D. 900), ABC reports.

"It's a very fascinating discovery," McIntosh told CNN. "Kilwa coins have only ever been found outside of the Kilwa region on two occasions.

"A single coin was found in … Zimbabwe, and one coin was found in the Arabian Peninsula, in what is now Oman, but nowhere else," McIntosh said. "And yet, here is this handful of them in northern Australia — this is the astonishing thing."

Will 5 coins rewrite history?

The Eurocentric view of history holds that Australia, populated by Aboriginal settlers for some 60,000 years, was "discovered" by European explorers in 1606.

But since the discovery of the ancient coins, which came to the attention of McIntosh before Isenberg died in 1991, that history may need to be rewritten. McIntosh also has the old map showing where the coins were discovered.

This July, McIntosh will carry that map back to the Wessel Islands, where he's leading an international team of researchers intent on solving the mystery of how the coins found their way to a remote beach in Australia.

"We have five separate hypotheses we're looking to test about how these coins got there — each one quite different from the other," McIntosh told CNN.

Some speculate that the Portuguese sailed along Australia's northern shores much earlier than was previously known. Another hypothesis suggests that African sailors from Kilwa were hired by merchants from the Far East to navigate the seas of China.

"Once you shift from the Eurocentric focus -- and this is how it could change Australian history -- you start seeing north Australia as part of this ancient trading network which links southern Africa, Arabian Persia, India, the Spice Islands and China," McIntosh told ABC.

Read more at Discovery News

Amazingly Untouched Royal Tomb Found in Peru

A rare, undisturbed royal tomb has been unearthed in Peru, revealing the graves of three Wari queens buried alongside gold and silver riches and possible human sacrifices.

Though the surrounding site has been looted many times, this mausoleum has managed to evade grave robbers for hundreds of years, archaeologists say.

Long before the Inca built Machu Picchu, the Wari empire flourished between A.D. 700 and 1000 throughout much of present-day Peru. At a time when Paris had just 25,000 residents, the Wari capital Huari was home to 40,000 people at its height, according to National Geographic, which reported the find. (In Photos: Amazing Ruins of the Ancient World)

Despite their reach, the Wari have remained somewhat mysterious, and it is rare for archaeologists to find burials that have not been ravaged by grave robbers. In hauling away treasures, looters destroy archaeological context and information, leaving researchers grasping for answers about how ancient people lived.

But a team led by Polish and Peruvian archaeologists discovered an underground mausoleum that's being billed as the first unlooted Wari imperial tomb, sealed for centuries under 30 tons (27 metric tons) of loose stone fill.

The 1,200-year-old chamber was found in El Castillo de Huarmey, north of Lima. Milosz Giersz, an archaeologist at the University of Warsaw in Poland, told National Geographic that he first saw a faint outline of the mausoleum in aerial photographs of the site.

In digging through to the "temple of the dead," the team reportedly discovered rows of human bodies buried in a seated position (some of them suspected to be human sacrifices). They also found three Wari queens in small side chambers among valuable grave goods, such as gold tools for weaving, brilliantly painted ceramic vessels and a drinking cup carved from alabaster.

The queens may not have been laid to rest for good after they died. National Geographic also reported that there were traces of insect pupae found in the queens' bodies, suggesting that their mummies may have been periodically put out on display, left exposed to the open air, to be venerated by the living Wari people.

Read more at Discovery News

Bizarre 500-Million-Year-Old Creature Unearthed

A new fossilized, cigar-shaped creature that lived about 520 million years ago has been unearthed in Morocco.

The new-found species, Helicocystis moroccoensis, has "characteristics that place it as the most primitive echinoderm that has fivefold symmetry," said study co-author Andrew Smith, a paleontologist at the Natural History Museum in London, referring to the group of animals that includes starfish and sea urchins. Modern echinoderms typically have five-point symmetry, such as the five arms of the starfish or the sand dollar's distinctive pattern.

The primitive sea creature, described today (June 25) in the journal Proceedings of the Royal Society B, could even change its body shape from slender to stumpy. Researchers say it is a transitional animal that could help explain how early echinoderms evolved their unique body plans, Smith said.

Cambrian explosion

In 2012, Smith and his colleagues were excavating in sediments dating to about 520 million years ago in the Anti-Atlas Mountains in Morocco, when they uncovered several specimens of the strange fossil.

The creature lived on the ancient supercontinent called Gondwana during the Cambrian Explosion, a period when all creatures inhabited the seas and life on the planet diversified dramatically.

One of the oldest known echinoderms, Helicoplacus — first unearthed in the White Mountains in California — had a spiral but asymmetrical body plan. And all modern echinoderms start off as larvae with bilateral symmetry, raising the question of how and when the creatures' distinctive five-point body plan originated.

New creatures

H. moroccoensis, named after the country where it was found, had a cylindrical body that extended up to 1.6 inches (4 centimeters) long. The echinoderm's mouth was on the top of its body, and it sported a cup made of checkered plates with a small stem at its base. It had a lattice-like skeleton made of calcite.

"It's a cigar-shaped beast, and it was able to expand and contract that cigar shape," Smith told LiveScience. "Sometimes it could be short and fat, and sometimes it could be long and thin."

The tiny sea creatures changed shape using a spiraling arrangement of five ambulacra, or grooves coming from the mouth that opened and closed to capture bits of food floating in the water.

The newly discovered species is the oldest known echinoderm with five ambulacra, and could shed light on how echinoderms evolved their unique body plans, Smith said.

H. moroccoensis was also found in sediments containing several other bizarre echinoderms, many of which had wacky body plans, ranging from completely asymmetrical to bilaterally symmetrical. That wide variety suggests the creatures were going through a period of dramatic diversification around that time period, Smith said.

Read more at Discovery News

Tomatoes' Genetic History from Wild to Salad

The fruit synonymous with summer, plump tomatoes, descended from tiny wild ancestors. The genetic footprints left by that journey recently were traced by an international team of plant biologists. The deciphered DNA map of the tomato and its wild relatives points to ways that the fruit could be bred to survive in harsh, desert conditions, which may become more common as climate change reshapes the world.

Domesticated tomatoes’ (Solanum lycopersicum) DNA showed signs of the artificial selection and breeding efforts that  brought about their significantly larger, redder fruit compared with wild relatives. However, the domestication of the tomato came with genetic drawbacks.

Centuries ago, the tomato appeared on European tables after Spanish conquistadors brought the plant from its Western Hemisphere homeland. Only a few plants and seeds made the journey across the Atlantic, which created what geneticists call a bottleneck, or a serious reduction in population that resulted in lower genetic diversity.

Many of tomato genes stayed in the Aztec gardens and wilderness of the Western Hemisphere. The imported plants grown in Europe ended up with a number of potentially damaging genes, which became widespread in the cultivated plants, according to the recent study published in Proceedings of the National Academy of Sciences (PNAS). These genes may have made the domesticated tomato slower-growing and frailer than their wild kin.

Plant breeders have tried for decades to improve the domesticated tomato by cross breeding it with wild relatives. The new maps of three wild tomato relatives’ DNA (Solanum pennellii, S. habrochaites and S. pimpinellifolium), may help breeders focus on specific traits more efficiently. Genetic testing of new tomato hybrids can now look for DNA markers from wild traits that could make domestic tomatoes as hardy as their wild kin.

In particular, one desert-dwelling tomato, S. pennellii, contains genes that give it a thicker waxy coating on fruits and leaves that prevent water loss, according to the PNAS study led by University of California – Davis biologists. The leaves of the desert tomato grow smaller and have fewer openings, called stomata, used for respiration. Also, the plant has hardy roots that can tolerate saltier soil.

Read more at Discovery News

Voyager Reaches Mystery Interstellar Doorstep

Voyager’s prolonged journey into interstellar space took another dramatic turn when the intrepid space probe last summer passed into a bizarre and unanticipated cosmic hallway between the bubble of space under the sun’s influence and whatever lies beyond.

On the celestial highway since September 1977, the Voyager 1 probe soared past Jupiter and Saturn in 1979 and 1980, respectively, then ended up an a path that led toward interstellar space. Eventually, the spacecraft will get there, but exactly when that will happen -- and what else it may encounter before then -- is anybody’s guess.

“The results of the measurements from Voyager have been surprising us not just since last August, but for about the last 2.5 years,” astronomer Stamatios Krimigis, with Johns Hopkinds University’s Applied Physics Laboratory, told Discovery News.

Scientists thought Voyager 1 had finally passed beyond the heliosheath, the outermost region of space touched by the solar wind, a stream of charged particles continuously flowing the sun. On Aug. 25, 2012, Voyager suddenly found itself in an uncharted region of space, marked by the abrupt disappearance of particles from the sun and the sudden rise of particles emanating from interstellar space.

“As far as we could tell there was absolutely no solar material in the vicinity of the spacecraft and there hasn’t been since then. At the same time, the cosmic rays coming from outside the system started to increase. We all thought at the time that, by God, we were probably out of the solar system,” Krimigis said.

But there were two other puzzling bits of data that didn’t fit that scenario.

The first mystery was why the magnetic field Voyager measured was still aligned like the sun’s -- and even more perplexing, why the magnetic field suddenly strengthened.

Scientists had expected to see a different magnetic orientation once Voyager was in interstellar space.

The second conundrum was why the cosmic ray particles were not evenly distributed. The thinking was -- and is -- that cosmic rays, which emanate from distant supernova explosions all over the galaxy, should be uniformly spread out in every direction in interstellar space.

The best scientists can conclude is that Voyager is in some sort of foyer where particles from inside and outside the solar system can easily flow, but which is not quite yet in interstellar space. The rather unpoetic name they came up for this zone is the “heliosheath depletion region.”

“What we have is kind of a hybrid. The magnetic field still seems to be the solar magnetic field, not the interstellar magnetic field, so how do you define interstellar medium if that’s the case? If you really need to finally reach the case where both the magnetic field and the plasma are from other stars, then we’re still not there,” lead project scientist Ed Stone, with the California Institute of Technology in Pasadena, told Discovery News.

Scientists have no idea how much longer it will take Voyager to reach the next and presumably last leg of its journey into interstellar space, but the proverbial clock is ticking.

The spacecraft, which is powered by the slow decay of radioactive plutonium, will begin running out of power for its science instruments in 2020.

“By then, we would have shut off everything we can shut off other than the instruments and will have to turn off the first instrument. As time goes on, each year there are four watts less available, we’ll have to turn off the second instrument,” Stone said.

By 2025, Voyager, which was originally designed to last just five years, will be completely shut down.

Read more at Discovery news

Jun 26, 2013

Horses Evolved 4 Million Years Ago

The ancestor of all living horses, donkeys and zebras lived about four million years ago, suggests a new study, pushing back the confirmed age of the horse’s progenitor by two million years.

The discovery comes from the genetic analysis of a 700,000-year old horse fossil trapped in the Canadian permafrost. That’s hundreds of thousands of years older than any genome ever sequenced before.

Among other insights, the sequence supports the often-debated view that the Przewalski’s horse, native to the Mongolian steppes, is the last living population of truly wild horses in the world.

And while the new study offers an intriguing look into the history of horses and how they have changed over millenia, the research also opens up the possibility of getting a much longer view into the evolution of all sorts of species, including people.

“This really shows that you can go much further back in time and do genomics than people previously thought,” said Eske Willerslev, an evolutionary geneticist at the University of Copenhagen. “Suddenly, that means that we can potentially go back and do the genome for precursors to Neanderthals. Maybe there’s potential for getting the genome of Homo erectus. From a scientific standpoint, this is really great.”

In 2003, Willerslev and colleagues retrieved a horse fossil from a site in Canada’s Yukon Territory, which contains some of the oldest permafrost on Earth. Based on volcanic ash preserved in the soil, the researchers estimated that the fossil was at least 700,000 years old.

When they scanned the bone for biomolecules, they were surprised to find both collagen and proteins, giving them hope that the bone might also still contain DNA, even though the oldest surviving DNA ever recovered from a fossil to date was only about 130,000 years old.

The team started with classic techniques to amplify DNA and build a genetic library, Willerslev said, but they ran into too much contamination. Most of the DNA they extracted belonged to microbes.

Instead, they turned to newer technologies to put together the full genome of the ancient creature. For comparison, they also sequenced the genomes of five domestic horse breeds, a donkey and a Przewalski’s horse, the rare wild horse that lives in central Asia.

Now that they had such an old specimen to contrast with modern versions, the researchers were able to calibrate the mutation rate and then work back to an age of origin for the ancestral horse. The Equus genus, they report today in the journal Science, emerged between four and 4.5 million years ago. Eventually, that lineage split, leading to modern Arabian horses, Icelandic horses, donkeys and related species.

There has been plenty of debate about when exactly Equus began, and while some paleontologists have suspected a history spanning 4 million years, the oldest known true horse fossil is only 2 million years old. The new findings strengthen the idea of an older history. “This study corroborates with molecular evidence what the fossils say,” said Bruce MacFadden, a paleontologist at the University of Florida, Gainesville. “It’s always interesting and good when two methods arrive at the same conclusion.”

With the ancient horse genome now available for reference, the new study offers insights into how natural selection shaped horses over time. It also offers opportunities to figure out which traits people focused on when they domesticated horses about 6,000 years ago, said James MacLeod, an equine genome expert at the University of Kentucky, Lexington’s Gluck Equine Research Center.

“Before, it was pure speculation, like ‘Oh, I think people wanted horses that were bigger and stronger to be war horses that could pull equipment and knights in heavy armor so I bet they selected for this,’” MacLeod said. “Now you could theoretically have data to back that up.”

What’s more, the data can now finally answer a long-standing question about whether the Przewalski’s horse is actually a wild strain or if it bred with domestic horses at some point in the past. According to the new work, the team reports that the Przewalski’s horse is truly wild.

Read more at Discovery News

Ancient Roman Road Exposed in Jerusalem

The worn-down flat stones of an ancient Roman road have been unearthed in Jerusalem, the Israeli Antiquities Authority (IAA) announced.

About 1,800 years ago, the road was one of two imperial arteries that connected Jerusalem to the ancient coastal city of Jaffa, now part of Tel Aviv. A well-preserved section of the path was exposed in northern Jerusalem during an excavation ahead of the installation of a drainage pipe, excavators say.

"Several segments of the road were previously excavated by research expeditions of the IAA, but such a finely preserved section of the road has not been discovered in the city of Jerusalem until now," David Yeger, who directed the excavation, said in an IAA statement.

"The Romans attached great importance to the roads in the empire," Yeger added. "They invested large sums of money and utilized the most advanced technological aids of the period in order to crisscross the empire with roads. These served the government, military, economy and public by providing an efficient and safe means of passage. Way stations and roadside inns were built along the roads, as well fortresses in order to protect the travelers."

The part of the road discovered in Jerusalem stretched 26 feet (8 meters) across and was bound on either side by curbstones, according to the IAA.

Though it has been largely covered up by modern development, parts of the road seem to have been in use long after the Romans left the region. For instance, the modern road in Bir Nabala, just northeast of Jerusalem, has been paved only a few centimeters above the ancient road, suggesting the Roman path had been used until a few decades ago, IAA officials said.

Read more at Discovery News

Earth's Deep Upwelling Limited to 2 Spots

Forget Yellowstone, Iceland and all those other wannabe volcanic hotspots. There are only two hotspots powered by true deep upwelling of heat and rock in the Earth’s mantle: The central Pacific Ocean and Africa.

A new study published today in Nature today argues that large-scale upwelling happens only in those two places, and also suggests that the two plumes from Earth’s depths have been very stable and have not moved much over the history of our planet. That’s despite the fact that the continents have formed and reformed several times and tectonic plates have been banging around continuously.

“For example, the Pangaea supercontinent formed and broke apart at the surface, but we think that the upwelling locations in the mantle have remained relatively constant despite this activity,” said Clinton Conrad, associate professor of geology at the University of Hawaii–Manoa’s School of Ocean and Earth Science and Technology (SOEST).

Conrad had long noted that tectonic plates tend to move northward. With that in mind, he and his colleagues started looking to see if there was some point in the Northern Hemisphere where the plates tended to be heading. They found it in eastern Asia.

Conrad then started looking for other important points on the planet for plate tectonics motions. With a bit of math, he discovered a plate tectonic “quadrupole” with two points of “net convergence” and two points of “net divergence” of tectonic plates. Overlaid on today’s planet, the researchers found the quadrupole locations of net divergence matched African and central Pacific locations where it’s generally thought mantle upwellings are now underway.

“This observation was interesting and important, and it made sense,” said Conrad.

Next, his team applied the same formula to the history of plate motions and plotted the points. They were astonished to see that the quadrupole points have not moved over geologic time. Why? Nobody knows. But the discovery provides a framework for begining to understand how mantle happenings can be linked to surface geology over the span of Earth’s history. In other words, this could be an underlying effect that could explain a lot of changes that have taken place on the surface of the Earth over the last few billion years.

Read more at Discovery News

Unlikely Planets Found in Violent Star Cluster

When it comes to forming planets, Mother Nature isn’t very picky. Despite horrific conditions inside densely packed open clusters, stars apparently have no problem forming and hanging on to an orbital brood.

That’s the conclusion from a new study that used data collected by NASA’s now-dormant Kepler space telescope to hunt for planets in a one-billion-year old open cluster called NGC 6811, a collection of about 70 stars located about 3,400 light years away in the constellation Cygnus.

Astronomers found two small Neptune-like planets orbiting sun-like stars in the cluster, which is believed to have once been far more populated than how it appears today.

The planets, named Kepler-66b and Kepler-67b, are not the first discovered in an open cluster (as opposed to free-flying so-called “field stars” which are easier to scan for planets) but they are the smallest.

To find two such worlds by Kepler, which sees only the fraction of planets that pass directly in front of their parent stars, relative to the telescope’s point of view, means that they should be as common as planets found orbiting field stars, said astronomer Soren Meibom with Harvard University.

The planets are too close to their host stars for liquid water, a condition believed to be necessary for life, and they are unlikely to even be solid bodies. Nevertheless, the study expands the domain where small planets can exist.

So far, the only place where planets haven’t been found yet is in globular clusters, an environment even more extreme that open clusters like NCG 6811.

“There is a threshold for when you cannot form planets or you make very different planets,” Meibom told Discovery News.

Astronomers believe most, if not all, stars started off in clusters, which then collapsed over time. Some member stars gradually drifted off, becoming field stars, taking their planets along with them.

What was unknown is if the most commonly found planets in the galaxy, the super-Earths and mini-Neptunes (none of which ironically appear in our own solar system) could survive all the gravitational elbowing, radiation bombardment, supernova explosions and other conditions resulting from so many stars being jammed into a relatively small slice of celestial real estate.

“It’s a very different birth environment than our own sun and planets,” Meibom said. “There was a very high probability that fragile planetary systems would fall apart.”

The study likely means that the estimate of 50 billion planets in the Milky Way galaxy, a number derived from Kepler data, is low since it does not include stars in clusters, added astronomer William Welsh, with San Diego State University.

“It looks like planets are just as common in clusters as everywhere else,” Welsh told Discovery News. “It is a little surprising because the cluster environment is harsh.”

Read more at Discovery News

Jun 25, 2013

Ten Thousandth Near-Earth Object Discovered in Space

More than 10,000 asteroids and comets that can pass near Earth have now been discovered. The 10,000th near-Earth object, asteroid 2013 MZ5, was first detected on the night of June 18, 2013, by the Pan-STARRS-1 telescope, located on the 10,000-foot (convert) summit of the Haleakala crater on Maui. Managed by the University of Hawaii, the PanSTARRS survey receives NASA funding.

Ninety-eight percent of all near-Earth objects discovered were first detected by NASA-supported surveys.

"Finding 10,000 near-Earth objects is a significant milestone," said Lindley Johnson, program executive for NASA's Near-Earth Object Observations Program at NASA Headquarters, Washington. "But there are at least 10 times that many more to be found before we can be assured we will have found any and all that could impact and do significant harm to the citizens of Earth." During Johnson's decade-long tenure, 76 percent of the NEO discoveries have been made.

Near-Earth objects (NEOs) are asteroids and comets that can approach the Earth's orbital distance to within about 28 million miles (45 million kilometers). They range in size from as small as a few feet to as large as 25 miles (41 kilometers) for the largest near-Earth asteroid, 1036 Ganymed.

Asteroid 2013 MZ5 is approximately 1,000 feet (300 meters) across. Its orbit is well understood and will not approach close enough to Earth to be considered potentially hazardous.

"The first near-Earth object was discovered in 1898," said Don Yeomans, long-time manager of NASA's Near-Earth Object Program Office at the Jet Propulsion Laboratory in Pasadena, Calif. "Over the next hundred years, only about 500 had been found. But then, with the advent of NASA's NEO Observations program in 1998, we've been racking them up ever since. And with new, more capable systems coming on line, we are learning even more about where the NEOs are currently in our solar system, and where they will be in the future."

Of the 10,000 discoveries, roughly 10 percent are larger than six-tenths of a mile (one kilometer) in size -- roughly the size that could produce global consequences should one impact the Earth. However, the NASA NEOO program has found that none of these larger NEOs currently pose an impact threat and probably only a few dozen more of these large NEOs remain undiscovered.

The vast majority of NEOs are smaller than one kilometer, with the number of objects of a particular size increasing as their sizes decrease. For example, there are expected to be about 15,000 NEOs that are about one-and-half football fields in size (460 feet, or 140 meters), and more than a million that are about one-third a football field in size (100 feet, or 30 meters). A NEO hitting Earth would need to be about 100 feet (30 meters) or larger to cause significant devastation in populated areas. Almost 30 percent of the 460-foot-sized NEOs have been found, but less than 1 percent of the 100-foot-sized NEOs have been detected.

When it originated, the NASA-instituted Near-Earth Object Observations Program provided support to search programs run by the Massachusetts Institute of Technology's Lincoln Laboratory (LINEAR); the Jet Propulsion Laboratory (NEAT); the University of Arizona (Spacewatch, and later Catalina Sky Survey) and the Lowell Observatory (LONEOS). All these search teams report their observations to the Minor Planet Center, the central node where all observations from observatories worldwide are correlated with objects, and they are given unique designations and their orbits are calculated.

"When I began surveying for asteroids and comets in 1992, a near-Earth object discovery was a rare event," said Tim Spahr, director of the Minor Planet Center. "These days we average three NEO discoveries a day, and each month the Minor Planet Center receives hundreds of thousands of observations on asteroids, including those in the main-belt. The work done by the NASA surveys, and the other international professional and amateur astronomers, to discover and track NEOs is really remarkable."

Within a dozen years, the program achieved its goal of discovering 90 percent of near-Earth objects larger than 3,300 feet (1 kilometer) in size. In December 2005, NASA was directed by Congress to extend the search to find and catalog 90 percent of the NEOs larger than 500 feet (140 meters) in size. When this goal is achieved, the risk of an unwarned future Earth impact will be reduced to a level of only one percent when compared to pre-survey risk levels. This reduces the risk to human populations, because once an NEO threat is known well in advance, the object could be deflected with current space technologies.

Currently, the major NEO discovery teams are the Catalina Sky Survey, the University of Hawaii's Pan-STARRS survey and the LINEAR survey. The current discovery rate of NEOs is about 1,000 per year.

Read more at Science Daily

Mysterious Manuscript Has Genuine Message

The Voynich Manuscript, an enigmatic book that has frustrated codebreakers and linguists for a century, contains a genuine message, according to a new computer analysis.

The study analyzed the unintelligible scripts that fill the about 250-page-long manuscript and extracted clusters of “keywords” which could serve as a good starting point in cryptographic attempts.

Described as “the world’s most mysterious manuscript,” the book takes its name from the rare book dealer Wilfrid Voynich, who discovered it in 1912 in the Villa Mondragone near Rome. He claimed the book had belonged to the 16th-century Habsburg emperor Rudolf II.

Radio carbon dating established the manuscript was penned on 15th-century parchment pages.

The book’s estimated 250,000 characters are totally alien and make “The Da Vinci Code” pale by comparison: arranged in groups like words and sentences, some resemble Latin letters and Roman numerals; others are unlike any known language.

Moreover, the puzzling handwriting is surrounded by intricately drawn illustrations: plants that can’t be identified, astrological symbols, elaborate networks of pipework and naked ladies dancing or bathing in a strange green liquid.

Modern scholars have thematically divided the manuscript into five sections: Herbal, Astrological, Biological, Pharmacological and Recipes.

“In spite of its unmistakable medieval-codex look, the origin, purpose and contents of the Voynich manuscript remain a deep mystery,” Marcelo Montemurro, a theoretical physicist from the University of Manchester, UK, and Damian Zanette, of the Statistical Physics Group at Centro Atómico Bariloche, Río Negro, Argentina, wrote in the journal Plos One.

“Since the seventeenth century, numerous attempts at deciphering the script have led to a few claims of success, but none of them has been convincing,” he added.

Speculations ranged from the manuscript being the secret work of a religious sect, the only remaining document from a forgotten language, an unbreakable secret code, and the recipe for the “elixir of life.”

Montemurro used a computerized statistical method to analyze the text at a large scale. Focusing on patterns of how the words were arranged, the study extracted “clusters” of cryptic words such as shedy, cthy, chor, qotedy and qokeey.

“The identification of these words is crucial for our analysis,” Montemurro told Discovery News.

The key idea behind the extraction of the keywords relies on the non-homogeneous use of content-bearing words in any text, with certain words being used with a higher-than-average frequency when a specific topic is discussed.

“At the statistical level this means that these words that define the topics in the text end up being used in a sort of clustered pattern. On the contrary, words that are not related to any specific topic, like for instance function words like ‘or’, ‘and’, ‘an’, have a much more uniform rate of use,” Montemurro said.

According to the researcher, if the words in the Voynich text are real encoded words, then this method could provide clues on which are the keywords that are more related to the book’s topics.

He noted that the manuscript presents a complex organization in the distribution of words that is compatible with those found in real language sequences.

The analysis also unveiled a relationship between the sections of the text that is consistent with similarities between the images.

“For instance, at the level of language, the Herbal and Pharmaceutical sections of the text are the most closely linked. Interestingly, these two sections are the ones sharing the lavish plant illustrations of the book,” Montemurro said.

Several experts dismissed the manuscript as a deliberate hoax, possibly forged by John Dee, an English mathematician and astrologer at Rudolph’s court.

In 2003 computer scientist Gordon Rugg demonstrated that text resembling that in the book could be generated with a Cardan grille, an encryption device invented around 1550.

Read more at Discovery News

Distant, Ancient Galaxies Reveal Formation

The Universe is a big place, and the most distant galaxies we can see date to a time when it was very different. With sensitive radio observations, astronomers in Australia have now peered into the birthplace of two galaxy groups from a time when the Universe was a fourth of its present age.

Using the Australia Telescope Compact Array, or ATCA, astronomers detected carbon monoxide (CO) gas in several galaxies 10 billion light years away. CO is a molecular gas and a tracer of the more abundant molecular hydrogen gas. It is from this gas that stars form in galaxies.

The Spiderweb Galaxy is a complex region where molecular gas was found in quantities of 60 billion times the mass of the sun. (For reference, our Milky Way Galaxy, a product of a later time in the Universe’s history, is 500 to 1000 billion times the mass of the sun.) Much of the mass is concentrated in a central galaxy, while other clumps are the sites of smaller, satellite galaxies. There is so much mass going into star formation in this region that astronomers infer that the burst of star formation will continue for another 40 million years. That is not unlike the bright starburst galaxies that we see with infrared telescopes.

Two more galaxies were observed thanks to gravitational lensing. This occurs when a nearer galaxy bends the light of a distant galaxy around it and towards us on Earth. This allows the more distant object to be seen by our telescopes. These galaxies were also detected with CO, the cold molecular gas that forms stars. These also hold billions of solar masses of star-forming material.

These two galaxies were detected in broad-spectrum radio light in addition to the emission lines of CO, and these galaxies were also detected in infrared surveys. Astronomers use this information to determine the star formation rate in these galaxies since the radio emission is dominated by emission near star forming regions and from cosmic rays accelerated by supernovae, the explosions of young, large stars.

These galaxies are forming stars at a rate of over 400 solar masses per year. Compare that to our Milky Way’s one solar mass per year of star formation. These distant galaxies are forming stars at a prodigious rate, not unlike, once again, those starburst galaxies we see in the infrared.

ATCA has recently undergone a sensitivity upgrade, allowing it to see more distant and dim emission from the spectral lines of carbon monoxide. This allows it to complement other facilities, such as the Atacama Large Millimeter/Submillimeter Array (ALMA) in Chile and the Very Large Array (VLA) in New Mexico. ATCA complements those arrays both in frequency and in location on Earth, being of overlapping frequencies with the VLA but available to see the Southern sky.

Read more at Discovery News

3 Habitable Super-Earths Orbiting Nearby Star

Gliese 667C is a well-studied star lying only 22 light-years from Earth in the constellation of Scorpius, but it appears to have been hiding a pretty significant secret. The star has at least six exoplanets in orbit, three of which orbit within the star’s “habitable zone” — the region surrounding a star that’s not too hot and not too cold for liquid water to exist on a planetary surface.

Where there’s the potential of liquid water, there’s the possibility for life. Therefore, if you were to gamble on the life-giving potential of any given star in the galaxy, Gliese 667C would triple your chances.

This unprecedented discovery is even more impressive as the trio are all “super-Earths” — worlds that are bigger than our planet and have the potential to possess rocky surfaces.

To make this landmark discovery, astronomers analyzed data from the High Accuracy Radial Velocity Planet Searcher (HARPS) instrument at the European Southern Observatory’s (ESO) 3.6-meter telescope in Chile. The instrument analyzes the very slight ‘wobble’ of stars caused by the gravitational tugging of any exoplanets in orbit. The ESO’s Very Large Telescope, the W.M. Keck Observatory and the Magellan Telescopes provided further data to make the discovery.

Astronomers already knew that Gliese 667C had three worlds in orbit, one in the star’s habitable zone, but the finding of three more exoplanets, two of which are also in the habitable zone is a huge discovery. Finding one small planet in a star’s habitable zone is exciting, but finding three is historic.

“The number of potentially habitable planets in our galaxy is much greater if we can expect to find several of them around each low-mass star — instead of looking at ten stars to look for a single potentially habitable planet, we now know we can look at just one star and find several of them,” said Rory Barnes, of the University of Washington, co-author of the study, in an ESO press release Tuesday (June 25).

Gliese 667C is one of three stars that orbit one another as a triple star system. It is a smaller star than our sun at only one third of its mass. Therefore, the energy emitted from the star is lower, forcing the habitable zone closer to the star. As a consequence, the orbital periods of the habitable trio are a lot shorter than what we are accustomed to living in the sun’s larger habitable zone.

But as with any exoplanet discovery, caution is urged to be aware that just because an exoplanet orbits within the habitable zone, it certainly doesn’t mean there is life on these worlds. We know very little else about the true habitability of the trio in Gliese 667C. Also, just because we know their masses, it doesn’t mean we know their physical sizes.

“Their estimated masses range from 2.7 to 3.8 that of the Earth’s,” Mikko Tuomi, of the University of Hertfordshire and co-investigator, told BBC News. “However, we can only estimate the physical sizes by assuming certain compositions that is, well, only educated guessing.

“Their orbital periods are 28, 39, and 62 days, which means that they all orbit the star closer to its surface than Mercury in our own system. Yet, the estimated surface temperatures enable the existence of liquid water on them because of the low luminosity and low mass of the star.”

Although the Gliese 667C system will be very alien when compared to our own solar system, there’s one key comparison that can be made. The solar system also has three planets within our star’s habitable zone — Venus, Earth and Mars — and we know there’s life on one of them. Venus and Mars may be skirting the inner and outer edges, respectively, of the sun’s habitable zone, but scientists believe that even Mars once had the conditions ripe for basic lifeforms to evolve.

Read more at Discovery News

Jun 24, 2013

Migrating Animals Add New Depth to How the Ocean 'Breathes'

The oxygen content of the ocean may be subject to frequent ups and downs in a very literal sense -- that is, in the form of the numerous sea creatures that dine near the surface at night then submerge into the safety of deeper, darker waters at daybreak.

Research begun at Princeton University and recently reported on in the journal Nature Geoscience found that animals ranging from plankton to small fish consume vast amounts of what little oxygen is available in the ocean's aptly named "oxygen minimum zone" daily. The sheer number of organisms that seek refuge in water roughly 200- to 650-meters deep (650 to 2,000 feet) every day result in the global consumption of between 10 and 40 percent of the oxygen available at these depths.

The findings reveal a crucial and underappreciated role that animals have in ocean chemistry on a global scale, explained first author Daniele Bianchi, a postdoctoral researcher at McGill University who began the project as a doctoral student of atmospheric and oceanic sciences at Princeton.

"In a sense, this research should change how we think of the ocean's metabolism," Bianchi said. "Scientists know that there is this massive migration, but no one has really tried to estimate how it impacts the chemistry of the ocean.

"Generally, scientists have thought that microbes and bacteria primarily consume oxygen in the deeper ocean," Bianchi said. "What we're saying here is that animals that migrate during the day are a big source of oxygen depletion. We provide the first global data set to say that."

Much of the deep ocean can replenish (often just barely) the oxygen consumed during these mass migrations, which are known as diel vertical migrations (DVMs).

But the balance between DVMs and the limited deep-water oxygen supply could be easily upset, Bianchi said -- particularly by climate change, which is predicted to further decrease levels of oxygen in the ocean. That could mean these animals would not be able to descend as deep, putting them at the mercy of predators and inflicting their oxygen-sucking ways on a new ocean zone.

"If the ocean oxygen changes, then the depth of these migrations also will change. We can expect potential changes in the interactions between larger guys and little guys," Bianchi said. "What complicates this story is that if these animals are responsible for a chunk of oxygen depletion in general, then a change in their habits might have a feedback in terms of oxygen levels in other parts of the deeper ocean."

The researchers produced a global model of DVM depths and oxygen depletion by mining acoustic oceanic data collected by 389 American and British research cruises between 1990 and 2011. Using the background readings caused by the sound of animals as they ascended and descended, the researchers identified more than 4,000 DVM events.

They then chemically analyzed samples from DVM-event locations to create a model that could correlate DVM depth with oxygen depletion. With that data, the researchers concluded that DVMs indeed intensify the oxygen deficit within oxygen minimum zones.

"You can say that the whole ecosystem does this migration -- chances are that if it swims, it does this kind of migration," Bianchi said. "Before, scientists tended to ignore this big chunk of the ecosystem when thinking of ocean chemistry. We are saying that they are quite important and can't be ignored."

Read more at Science Daily

Two Mutations Triggered an Evolutionary Leap 500 Million Years Ago

Evolution, it seems, sometimes jumps instead of crawls. A research team led by a University of Chicago scientist has discovered two key mutations that sparked a hormonal revolution 500 million years ago.

In a feat of "molecular time travel," the researchers resurrected and analyzed the functions of the ancestors of genes that play key roles in modern human reproduction, development, immunity and cancer. By re-creating the same DNA changes that occurred during those genes' ancient history, the team showed that two mutations set the stage for hormones like estrogen, testosterone and cortisol to take on their crucial present-day roles.

"Changes in just two letters of the genetic code in our deep evolutionary past caused a massive shift in the function of one protein and set in motion the evolution of our present-day hormonal and reproductive systems," said Joe Thornton, PhD, professor of human genetics and ecology & evolution at the University of Chicago, who led the study.

"If those two mutations had not happened, our bodies today would have to use different mechanisms to regulate pregnancy, libido, the response to stress, kidney function, inflammation, and the development of male and female characteristics at puberty," Thornton said.

The findings were published online June 24 in the Proceedings of the National Academy of Sciences.

Understanding how the genetic code of a protein determines its functions would allow biochemists to better design drugs and predict the effects of mutations on disease. Thornton said the discovery shows how evolutionary analysis of proteins' histories can advance this goal, Before the group's work, it was not previously known how the various steroid receptors in modern species distinguish estrogens from other hormones.

The team, which included researchers from the University of Oregon, Emory University and the Scripps Research Institute, studied the evolution of a family of proteins called steroid hormone receptors, which mediate the effects of hormones on reproduction, development and physiology. Without receptor proteins, these hormones cannot affect the body's cells.

Thornton's group traced how the ancestor of the entire receptor family -- which recognized only estrogens -- evolved into descendant proteins capable of recognizing other steroid hormones, such as testosterone, progesterone and the stress hormone cortisol.

To do so, the group used a gene "resurrection" strategy. They first inferred the genetic sequences of ancient receptor proteins, using computational methods to work their way back up the tree of life from a database of hundreds of present-day receptor sequences. They then biochemically synthesized these ancient DNA sequences and used molecular assays to determine the receptors' sensitivity to various hormones.

Thornton's team narrowed down the time range during which the capacity to recognize non-estrogen steroids evolved, to a period about 500 million years ago, before the dawn of vertebrate animals on Earth. They then identified the most important mutations that occurred during that interval by introducing them into the reconstructed ancestral proteins. By measuring how the mutations affected the receptor's structure and function, the team could re-create ancient molecular evolution in the laboratory.

They found that just two changes in the ancient receptor's gene sequence caused a 70,000-fold shift in preference away from estrogens toward other steroid hormones. The researchers also used biophysical techniques to identify the precise atomic-level mechanisms by which the mutations affected the protein's functions. Although only a few atoms in the protein were changed, this radically rewired the network of interactions between the receptor and the hormone, leading to a massive change in function.

Read more at Science Daily

Bumpy-Faced Beastie Dominated Before Dinos

Over 250 million years ago, just before the first known dinosaurs emerged, the bumpy-faced beast Bunostegos dominated the world’s one big desert.

The reptile struck quite a pose on the dry central Pangea landscape. (Pangea, aka “All Earth,” was the enormous supercontinent that existed before the land mass broke up into parts.) The beast’s territory is now northern Niger.

“Imagine a cow-sized, plant-eating reptile with a knobby skull and bony armor down its back,” Linda Tsuji of the University of Washington, who led the research, was quoted as saying in a press release.

The aptly-named genus Bunostegos means “knobby roof.”

This distinctive prehistoric animal was a pareiasaur, meaning a large, plant-loving reptile common across Pangea. Most of these beasts had bony knobs on their skulls, but Bunostegos sported the largest and most bulbous ones ever discovered. These knobs were like the skin-covered horns (technically called ossicones) seen today on modern giraffes, or at least that’s the present theory.

In giraffes, these bumps help to distinguish males from females, since only females have obvious tufts of fur on theirs. They also help to protect the heads of males during combat, which is one reason why the bumps are usually hairless on males. Over time, the hair and skin on them wears away. Perhaps the bumps held similar functions in pareiasaurs.

Since Bunostegos had characteristics of even earlier reptiles, the researchers think a population of these cow-sized reptiles persisted in the supercontinent, essentially isolated, for millions of years.

“Our work supports the theory that central Pangea was climatically isolated, allowing a unique relict fauna to persist into the late Permian,” said co-author Christian Sidor, also from the University of Washington.

This is surprising, he said, because areas outside the central Pangea region show fossil evidence of regular faunal interchange back in pre-dino times.

Paleontologist Gabe Bever, who was not involved with the study, said, “Research in these lesser-known basins is critically important for meaningful interpretation of the Permian fossil record. Our understanding of the Permian and the mass extinction that ended it depends on discovery of more fossils like the beautifully bizarre Bunostegos.”

Read more at Discovery News

Plants Do Math to Survive the Night

Plants use a chemical calculator to divide their amount of stored energy by the length of the night and thereby solve the problem of how to portion out their energy reserves overnight.

Biologists from the John Innes Centre in England discovered that plants have a biological process which divides their amount of stored energy by the length of the night. This solves the problem of how to portion out energy reserves during the night so that the plant can keep growing, yet not risk burning off all its stored energy.

While the sun shines, plants perform photosynthesis. In this process, the plants convert sunlight, water and carbon dioxide into stored energy in the form of long chains of sugar, called starch. At night, the plants burn this stored starch to fuel continued growth.

“The calculations are precise so that plants prevent starvation but also make the most efficient use of their food,” study co- author Alison Smith said in press release. “If the starch store is used too fast, plants will starve and stop growing during the night. If the store is used too slowly, some of it will be wasted.”

To give the foliage a math quiz, the biologists shut off the lights early on plants that had been grown with 12-hour days and nights. Plunging the plants into darkness after only an 8-hour day forced them to adjust their normal nightly rhythm. Since the plants didn’t have time to store as much starch as usual, they had to recalculate their metabolism.

Even after this day length trickery, the plants aced their exams and ended up with just a small amount of starch left over in the morning. They had neither starved, nor stored starch that could have been used to fuel more growth.

The plants weren’t doing anything consciously. Instead, chemical reactions did the number crunching automatically. The results of the study will be published in eLife, and can currently be read via the Cornell University Library.

Read more at Discovery News

Jun 23, 2013

Scientists Solve Riddle of Strangely Behaving Magnetic Material

Materials scientists at the U.S. Department of Energy's (DOE) Ames Laboratory have found an accurate way to explain the magnetic properties of a compound that has mystified the scientific community for decades.

The compound of lanthanum, cobalt and oxygen (LaCoO3) has been a puzzle for over 50 years, due to its strange behavior. While most materials tend to lose magnetism at higher temperatures, pure LaCoO3 is a non-magnetic semiconductor at low temperatures, but as the temperature is raised, it becomes magnetic. With the addition of strontium on the La sites the magnetic properties become even more prominent until, at 18 percent strontium, the compound becomes metallic and ferromagnetic, like iron.

"They knew that we could calculate x-ray absorption and magnetic dichroism, so we started doing that. It is a case where we fell into doing what we thought was a routine calculation, and it turned out we discovered a totally different explanation," said Harmon. "We found we could explain pretty much everything in really nice detail, but without explicitly invoking that local model," said Harmon.

The scientists found that a small rhombohedral distortion of the LaCoO3 lattice structure, which had largely been ignored, was key.

"We found that the total electronic energy of the lattice depends sensitively on that distortion," explained Harmon. "If the distortion becomes smaller (the crystal moves closer to becoming cubic), the magnetic state of the crystal switches from non-magnetic to a state with 1.3 Bohr magnetons per Co atom."

Ames Laboratory scientists Bruce Harmon and Yongbin Lee partnered with the researchers at the Argonne National Laboratory and the University of California, Santa Cruz to publish a paper in Physical Review Letters, "Evolution of Magnetic Oxygen States in Sr-Doped LaCO3."

This new understanding may help the further development of these materials, which are easily reduced to nanoparticles; these are finding use in catalytic oxidation and reduction reactions associated with regulation of noxious emissions from motor vehicles.

Read more at Science Daily

Unexpected Discovery of the Ways Cells Move Could Boost Understanding of Complex Diseases

A new discovery about how cells move inside the body may provide scientists with crucial information about disease mechanisms such as the spread of cancer or the constriction of airways caused by asthma. Led by researchers at Harvard School of Public Health (HSPH) and the Institute for Bioengineering of Catalonia (IBEC), investigators found that epithelial cells -- the type that form a barrier between the inside and the outside of the body, such as skin cells -- move in a group, propelled by forces both from within and from nearby cells -- to fill any unfilled spaces they encounter.

The study appears June 23, 2013 in an advance online edition of Nature Materials.

"We were trying to understand the basic relationship between collective cellular motions and collective cellular forces, as might occur during cancer cell invasion, for example. But in doing so we stumbled onto a phenomenon that was totally unexpected," said senior author Jeffrey Fredberg, professor of bioengineering and physiology in the HSPH Department of Environmental Health and co-senior investigator of HSPH's Molecular and Integrative Cellular Dynamics lab.

Biologists, engineers, and physicists from HSPH and IBEC worked together to shed light on collective cellular motion because it plays a key role in functions such as wound healing, organ development, and tumor growth. Using a technique called monolayer stress microscopy -- which they invented themselves -- they measured the forces affecting a single layer of moving epithelial cells. They examined the cells' velocity and direction as well as traction -- how some cells either pull or push themselves and thus force collective movement.

As they expected, the researchers found that when an obstacle was placed in the path of an advancing cell layer -- in this case, a gel that provided no traction -- the cells moved around it, tightly hugging the sides of the gel as they passed. However, the researchers also found something surprising -- that the cells, in addition to moving forward, continued to pull themselves collectively back toward the gel, as if yearning to fill the unfilled space. The researchers dubbed this movement "kenotaxis," from the Greek words "keno" (vacuum) and "taxis" (arrangement), because it seemed the cells were attempting to fill a vacuum.

This new finding could help researchers better understand cell behavior -- and evaluate potential drugs to influence that behavior -- in a variety of complex diseases, such as cancer, asthma, cardiovascular disease, developmental abnormalities, and glaucoma. The finding could also help with tissue engineering and regenerative medicine, both of which rely on cell migration.

In carcinomas, for instance -- which represent 90% of all cancers and involve epithelial cells -- the new information on cell movement could improve understanding of how cancer cells migrate through the body. Asthma research could also get a boost, because scientists think migration of damaged epithelial cells in the lungs are involved in the airway narrowing caused by the disease.

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