May 19, 2012

A Crowning Success for Crayfish

Nature sometimes copies its own particularly successful developments. A team of scientists from the Max Planck Institute of Colloids and Interfaces in Potsdam and the Ben-Gurion University at Beer-Sheva in Israel has now found that the teeth of the Australian freshwater crayfish Cherax quadricarinatus are covered with an enamel amazingly similar to that of vertebrates. Both materials consist of calcium phosphate and are also very alike in terms of their microstructure. This extremely hard substance has apparently developed in freshwater crayfish independently from vertebrates, as it makes the teeth particularly strong.

In terms of hardness, enamel sets a unique standard, which is hardly met by any other other biological material. The hardness and strength of the outer layer of the crown of the tooth in humans and other vertebrates are due to tiny crystals of calcium phosphate, which also strengthen bones. And because the composition and structure of the enamel have made it exceptionally strong, the evolution in freshwater crayfish, too, has produced a highly mineralised protective layer for the mandibles that is very similar to enamel in vertebrates, as Barbara Aichmayer and her colleagues at the Max Planck Institute in Potsdam in cooperation with Amir Berman and Amir Sagi of the Ben-Gurion University in Beer-Sheva have now discovered. "We assume," she explains, "that in the course of their evolution both vertebrates and freshwater crayfish developed enamel-like structures independently of one another. These amazing materials are a perfect answer to similar demands on the masticatory organs."

The enamel of freshwater crayfish is heavily fluoridated by nature

The mandibles of the freshwater crayfish are part of the cuticle which, as in other crustaceans, consists essentially of a network of chitin fibres. The shell is hardened in particular by disordered calcium carbonate, which is termed amorphous by scientists. In the mandibles of freshwater crayfish, the softer compound material of chitin and amorphous calcium carbonate, however, is covered with a thin layer which, like human enamel, is composed predominantly of crystalline calcium phosphate. This is remarkable because the constituent calcium phosphate is rarely found in the exoskeleton of invertebrates. The elongated shape of the crystals and their arrangement perpendicular to the surface of the teeth, too, match the structure of human enamel to a large extent and produces similar mechanical properties. The structure makes the material extremely hard and at the same time highly resistant to crack propagation, giving the tooth perfect protection against destruction.

However, there is one aspect in which the teeth of freshwater crayfish differ from those of vertebrates: Their enamel contains a high level of fluoride that makes it much less water-soluble -- all without taking fluoride tablets. In freshwater, the habitat of the freshwater crayfish, this is particularly important, because minerals containing calcium dissolve more easily there than in salt water.

Read more at Science Daily

Rabies Evolves Slower in Hibernating Bats

The rate at which the rabies virus evolves in bats may depend heavily upon the ecological traits of its hosts, according to researchers at the University of Georgia, the U.S. Centers for Disease Control and Prevention and Katholieke Universiteit Leuven in Belgium. Their study, published May 17 in the journal PLoS Pathogens, found that the host's geographical location was the most accurate predictor of the viral rate of evolution. Rabies viruses in tropical and sub-tropical bat species evolved nearly four times faster than viral variants in bats in temperate regions.

"Species that are widely distributed can have different behaviors in different geographical areas," said Daniel Streicker, a postdoctoral associate in the UGA Odum School of Ecology and the study's leader. "Bats in the tropics are active year-round, so more rabies virus transmission events occur per year. Viruses in hibernating bats, on the other hand, might lose up to six months' worth of opportunities for transmission."

Understanding the relationship between host ecology and viral evolution rates could shed light on the transmission dynamics of other viruses, such as influenza, that occur across regions, infect multiple host species or whose transmission dynamics are impacted by anthropogenic change.

The team's findings could eventually help public health officials better predict when rabies virus transmission could happen in different environments and as environments change, but Streicker cautions that more research into the rabies virus genome and bats' overwintering ecology is needed.

"If viral evolution is faster, it could potentially lead to greater genetic diversity in crucial parts of the viral genome that allow it to shift hosts," he said. "For rabies, we don't yet know what those are, so identifying them will be key. Similarly, before understanding whether climate change will speed viral evolution, we need a better idea of how environmental changes will influence host ecology and behavior."

Evolutionary biologists have long recognized that molecular evolution proceeds in a largely clock-like manner, with mutations accumulating at a fairly constant rate over time. This "molecular clock" allows for powerful inferences -- from dating the origins of species to the origins of epidemics. However, the rate at which the clock ticks varies dramatically among species; much research has focused on what causes these differences.

For RNA viruses such as rabies, understanding the rate variability has practical implications, since faster evolution can enable viral emergence in new species or allow a virus to evade its host's immune defenses. However, nearly all past studies compared viruses of completely different families and were therefore limited to focusing on viral structural traits. Since few opportunities existed to study the evolution of similar viruses in different host species, the role of the host had been almost completely neglected.

Streicker set out to better understand the tempo of the evolution of rabies viruses in bats, and specifically what, if any, role the host species played.

To conduct the study, Streicker and his colleagues compiled a database of rabies virus genetic sequences from infected bats in the U.S. and South America, representing 21 different variants of the virus. They also collected information on the biology and ecology of the different bat species that served as viral hosts. They looked at the evolutionary history of the different bat species; their overwintering behavior (whether the bats hibernated, went through periods of torpor or remained active during the winter); their metabolic rates; and their migration habits (whether they engaged in long distance migration). They also classed the bats by climatic region and whether they were solitary or roosted in colonies.

Their analysis of this enormous database revealed extreme variability in the rate of evolution in different rabies viruses, comparable to the differences seen between viruses of entirely different families. The analysis also suggested that viral genetic traits were not chiefly responsible for this variation since rates seemed to shift freely throughout the ancestral history of the rabies virus as it jumped into new bat species.

"Earlier studies led to the conclusion that viral genomic traits are driving the evolution rate," Streicker said. "It turns out that's not the whole story. In this case, host biology plays an important role."

The trait that best correlated with the rate of viral evolution was not the host's evolutionary history. It was its climatic region, which affects the bats' behavior.

Rabies in tropical bats goes through more generations per year than in temperate bats, a mechanism also hypothesized to accelerate how quickly the molecular clock ticks in free-living tropical plants and animals. The rapid evolution in rabies viruses provided the researchers with an opportunity to examine one of the mechanisms thought to drive the differences in evolution and species diversity across latitudes from the poles to the tropics.

"This is just another example of how the fast pace of evolution in RNA viruses makes them exceptional tools for understanding simultaneously ecological and evolutionary processes," Streicker said.

Read more at Science Daily

Tyrannosaur Skeleton For Sale, But Ownership Is Questioned

The origin of a rare tyrannosaur skeleton, now sitting mounted and prepared at an auction house in New York City, has been questioned, with some saying the specimen is from Mongolia; if so, that would mean it entered the United States illegally.

The rare Tyrannosaurus bataar — standing 8 feet (2.4 meters) tall and 24 feet (7.3 m) long — is to be auctioned Sunday (May 20) by Heritage Auctions.

An email to LiveScience late on Friday afternoon claimed the Mongolian President Elbegdorj Tsakhia was raising concerns that the specimen was actually his country's property. The email contained a note signed by Mark Norell, a vertebrate paleontologist at the American Museum of Natural History in New York City.

"There is no legal mechanism (nor has there been for over 50 years) to remove vertebrate fossil material from Mongolia. These specimens are the patrimony of the Mongolian people and should be in a museum in Mongolia," the letter reads.

Norell confirmed that the letter was his.

The auction house stands by their collection, saying the items legally entered the United States.

"There is nothing from Mongolia that is legal. It's not that I am against the commercial trade of fossils, it's just different countries have different laws," Norell told LiveScience, adding that Heritage Auctions avoids giving the specific locality for the origin of the fossil in their catalog of natural history items to be auctioned.

The description, he said, only states the skeleton is from Central Asia, though if the specimen did indeed come from China, it would still be illegal.

David Herskowitz, director of natural history for Heritage Auctions, said the T. bataar skeleton entered the United States legally, adding in a statement that "no one knows where exactly it was dug up. They'd have to find the hole and match up the matrix."

While the tyrannosaur skeleton is the headliner, several other natural-history specimens are also set to be auctioned Sunday. Of these, Norell says he is also concerned an ankylosaur skull and T. bataar teeth may also be from Mongolia; the teeth described in the auction house's catalog say they came from a formation that Norell says only exists in Mongolia.

Regarding the T. bataar skeleton and the ankylosaur, Norell said, "They say they are from Central Asia, but the only places those two animals have ever been collected have been from Mongolia."

Read more at Discovery News

Tiny Deep-Sea Life Eats Dinosaur-Era Meals

Microbes living in the seabed below the deep ocean are taking the slow-food movement to extremes. According to new research, these microorganisms are subsisting on nutrients first laid down when dinosaurs still walked the Earth.

Nutrient-carrying sediment rarely makes it to the deep seafloor at the North Pacific Gyre far north of Hawaii. If a grain of sand falls to the seabed, it will be another 1,000 years before another grain lands on top of it, said Hans Røy, aquatic ecologist at Aarhus University in Denmark and leader of the new study, published Thursday (May 17) in the journal Science. And yet, an expedition to the North Pacific turned up populations of incredibly slow-living microbes in these depths.

"It's pretty amazing, because if you look at the deepest parts, these are layers that were laid down back when the dinosaurs were walking on this planet, and there has been no input of new organic material since that," Røy told LiveScience. "They've been chewing on the same bone for 86 million years."

Microbial mission

Research stretching back to the late 1980s suggests that as much as 90 percent of the Earth's microorganisms live in the seabed, Røy said. But these microbial communities remain mysterious, largely because they resist typical laboratory experiments. If you wanted to measure the metabolism (how fast the body uses energy) of microbes living in coastal mud, you'd simply take some mud and track how fast they burned through the oxygen in that sample. Because coastal seafloor organisms live in a nutrient-rich, fast-turnover world, the experiment would only take a few minutes.

To do the same thing with the slow-living bacteria found beneath the North Pacific Gyre, you'd have to wait 1,000 years to detect a change in oxygen levels, Røy said.

That's what makes the new discovery important, he said. The bacterial communities living in the Pacific have been chugging along for millions of years. All scientists have to do is go out and measure their activities.

During an expedition on the U.S. Navy research vessel R/V Knorr, Røy and his colleagues drilled long columns of sediment called cores out of the seabed. They first sampled from a long stretch along the equator, varying their distance from land, but not their latitude. Next, the vessel sailed north into the Pacific, and researchers took seabed samples at different latitudes, but all at equal distances from land.

Slow living in the seafloor

In most places, oxygen penetrates only a millimeter into the ocean bed, sometimes making it as much as about a foot and a half (0.5 meters) in deep-sea zones. But in the deep North Pacific Gyre, researchers hauled up cores 98 feet (30 m) long and found oxygen reaching all the way down.

The reason, Røy said, is that so few nutrients reach the seabed here that the microbes in the seafloor barely eat. When they don't eat, they don't use oxygen. Thus, the oxygen hangs around in the sediment for thousands of years.

The researchers aren't sure how old the individual microbes in the colonies are. It takes the microbes 1,000 years to double their biomass, they calculated. In comparison, a familiar microbe like the food-poisoning bug salmonella might take between 20 minutes and two hours to double, depending on its environment.

Cells double their biomass to divide, so the results suggest the microbes are at least 1,000 years old. But that number is a minimum, Røy said.

"Maybe they grow and divide, but the result could just as well indicate that they have a long repair cycle where over a 1,000-year period, they actually replace all the compartments of the cell," he said. "If that is the case, the cells could be much older."

Read more at Discovery News

May 18, 2012

Bronze-Age 'Facebook' Stone Conveyed 'Likes'

A Bronze Age version of Facebook has emerged from granite rocks in Russia and northern Sweden, revealing a thousands-of-years-old timeline filled with an archaic version of the Facebook "like."

Using computer modeling, Mark Sapwell, a Ph.D. archaeology student at Cambridge University, analyzed some 3,500 rock art images from Nämforsen in Northern Sweden and Zalavruga in Western Russia.

"Although this rock art has been documented from the early 1900s, the modeling has allowed a unique look at the interesting way these images have been arranged and accumulated over time," Sapwell told Discovery News.

Carved from about 4000 B.C. up to the Bronze Age, the rock art shows animals, people, boats, hunting scenes -- even very early centaurs and mermaids. It was produced by generations of semi nomadic people, who lived more inland in winter to hunt elk, and then occupied areas closer to coasts and rivers to fish.

As they were located in important and prominent locations on river crossroads, the rock art landscapes were likely very visible points where passing travellers would take notice of the traces of people who came before them, adding their own mark on the world.

"The rock art we see today is the result of a culmination of many repeated acts of carving, each responding to each other over time. Like a Facebook status invites comment, the rock art appears very social and invites addition," Sapwell said.

Usually clustered on the granite rocks, the images ranged from groups of one to two images to rock art panels with over 500 images. Larger clusters represented a greater response and conversation between people.

Read more at Discovery News

Island Platypuses Face Risky Future

Safety really is in the numbers for some of Australia's iconic animals with a new study showing small island populations of platypus are in danger of being wiped out because of a lack of genetic diversity.

The finding could help improve management of other animal populations with low genetic variation such as the koala and helps explain the decimation of the Tasmanian devils from a contagious cancer.

The paper, published this month in the Journal of Heredity, shows platypuses on the Australian mainland and in Tasmania have high levels of genetic diversity within their populations.

However those platypuses found on King Island, north-west of Tasmania, and Kangaroo Island, south-west of Adelaide, are at high risk of being wiped out.

For the study, University of Sydney doctoral student Mette Lillie, examined the immune genes of 70 platypuses from populations in Queensland, New South Wales, Victoria, Tasmania and the two smaller islands.

She says the study shows the King Island population has no diversity in its major histocompatibility complex (MHC) gene which plays a critical role in the immune system identifying pathogens and disease.

"If you have lots of variation in the MHC gene it means the populations is better able to resist disease and pathogens," Lillie says.

She says the genetic diversity has been lost because the King island population is an endemic species that has been isolated from other populations since the last Ice Age about 14,000 years ago.

Genetic diversity would have been reduced through inbreeding and random genetic drift - evolutionary forces or events that dramatically change or influence genetic diversity from generation to generation.

She says around 20 platypuses were introduced to Kangaroo Island in the 1930s and 1940s and the lack of genetic diversity is to be expected given the small size of the original population.

Read more at Discovery News

Car-Sized Turtle Found in Colombian Coal Mine

Remains of an enormous turtle, which was the size of a Smart car, have been unearthed in a Colombian coal mine.

The shell alone of the 60-million-year-old turtle, Carbonemys cofrinii aka "coal turtle," is large enough to be a small swimming pool. Its skull is roughly the size of a regulation NFL football.

The coal mine where it was found is part of northern Colombia's Cerrejon formation.

"We had recovered smaller turtle specimens from the site," Edwin Cadena, a North Carolina State doctoral student who discovered the turtle, said in a press release. "But after spending about four days working on uncovering the shell, I realized that this particular turtle was the biggest anyone had found in this area for this time period -- and it gave us the first evidence of giant-ism in freshwater turtles."

The find was described in the latest Journal of Systematic Paleontology.

Relatives of Carbonemys existed alongside dinosaurs, but these turtles were much smaller. This gigantic version appeared five million years after dinos went extinct, during a period when giant varieties of many different reptiles -- including Titanoboa cerrejonensis, the largest snake ever discovered -- lived in this part of South America.

Why were the animals so big?

Cadena and other experts believe that a combination of changes in the ecosystem, including fewer predators, a larger habitat area, plentiful food supply and climate changes, worked together to allow these giant species to survive. Carbonemys' habitat would have resembled a much warmer modern-day Orinoco or Amazon River delta.

Read more at Discovery News

May 17, 2012

Religion Is a Potent Force for Cooperation and Conflict, Research Shows

Across history and cultures, religion increases trust within groups but also may increase conflict with other groups, according to an article in a special issue of Science.

"Moralizing gods, emerging over the last few millennia, have enabled large-scale cooperation and sociopolitical conquest even without war," says University of Michigan anthropologist Scott Atran, lead author of the article with Jeremy Ginges of the New School for Social Research.

"Sacred values sustain intractable conflicts like those between the Israelis and the Palestinians that defy rational, business-like negotiation. But they also provide surprising opportunities for resolution."

As evidence for their claim that religion increases trust within groups but may increase conflict with other groups, Atran and Ginges cite a number of studies among different populations. These include cross-cultural surveys and experiments in dozens of societies showing that people who participate most in collective religious rituals are more likely to cooperate with others, and that groups most intensely involved in conflict have the costliest and most physically demanding rituals to galvanize group solidarity in common defense and blind group members to exit strategies. Secular social contracts are more prone to defection, they argue. Their research also indicates that participation in collective religious ritual increases parochial altruism and, in relevant contexts, support for suicide attacks.

They also identify what they call the "backfire effect," which dooms many efforts to broker peace. In many studies that Atran and Ginges carried out with colleagues in Palestine, Israel, Iran, India, Indonesia and Afghanistan, they found that offers of money or other material incentives to compromise sacred values increased anger and opposition to a deal.

"In a 2010 study, Iranians who regarded Iran's right to a nuclear program as a sacred value more violently opposed sacrificing Iran's nuclear program for conflict-resolution deals involving substantial economic aid, or relaxation of sanctions, than the same deals without aid or sanctions," they write. "In a 2005 study in the West Bank and Gaza, Palestinian refugees who held their 'right of return' to former homes in Israel as a sacred value more violently opposed abandoning this right for a Palestinian state plus substantial economic aid than the same peace deal without aid."

This dynamic is behind the paradoxical reality that the world finds itself in today: "Modern multiculturalism and global exposure to multifarious values is increasingly challenged by fundamentalist movements to revive primary group loyalties through greater ritual commitments to ideological purity."

But Atran and Ginges also offer some insights that could help to solve conflicts fueled by religious conviction. Casting these conflicts as sacred initially blocks standard business-like negotiation tactics. But making strong symbolic gestures such as sincere apologies and demonstrations of respect for the other's values generates surprising flexibility, even among militants and political leaders, and may enable subsequent material negotiations, they point out.

"In an age where religious and sacred causes are resurgent, there is urgent need for joint scientific effort to understand them," they conclude. "In-depth ethnography, combined with cognitive and behavioral experiments among diverse societies (including those lacking a world religion), can help identify and isolate the moral imperatives for decisions on war or peace."

Read more at Science Daily

Giant Galaxy-Packed Filament Revealed

A McGill-led research team using the Herschel Space Observatory has discovered a giant, galaxy-packed filament ablaze with billions of new stars. The filament connects two clusters of galaxies that, along with a third cluster, will smash together and give rise to one of the largest galaxy superclusters in the universe.

The filament is the first structure of its kind spied in a critical era of cosmic buildup when colossal collections of galaxies called superclusters began to take shape. The glowing galactic bridge offers astronomers a unique opportunity to explore how galaxies evolve and merge to form superclusters.

"We are excited about this filament, because we think the intense star formation we see in its galaxies is related to the consolidation of the surrounding supercluster," said Kristen Coppin, a postdoctoral fellow in astrophysics at McGill and lead author of a new paper in Astrophysical Journal Letters.

"This luminous bridge of star formation gives us a snapshot of how the evolution of cosmic structure on very large scales affects the evolution of the individual galaxies trapped within it," said Jim Geach, a co-author also based at McGill.

The intergalactic filament, containing hundreds of galaxies, spans 8 million light-years and links two of the three clusters that make up a supercluster known as RCS2319. This emerging supercluster is an exceptionally rare, distant object whose light has taken more than seven billion years to reach us.

RCS2319 is the subject of a huge observational study, led by Professor Tracy Webb and her group at McGill's Department of Physics. Previous observations in visible and X-ray light had found the cluster cores and hinted at the presence of a filament. It was not until astronomers trained Herschel on the region, however, that the intense star-forming activity in the filament became clear. Dust obscures much of the star-formation activity in the early universe, but telescopes like Herschel can detect the infrared glow of this dust as it is heated by nascent stars. (The Herschel Space Observatory is a European Space Agency mission with important NASA contributions.)

The amount of infrared light suggests that the galaxies in the filament are cranking out the equivalent of about 1,000 solar masses (the mass of our sun) of new stars per year. For comparison's sake, our Milky Way galaxy is producing about one solar mass-worth of new stars per year.

Researchers chalk up the blistering pace of star formation in the filament to the fact that galaxies within it are being crunched into a relatively small cosmic volume under the force of gravity. "A high rate of interactions and mergers between galaxies could be disturbing the galaxies' gas reservoirs, igniting bursts of star formation," said Geach.

By studying the filament, astronomers will be able to explore the fundamental issue of whether "nature" versus "nurture" matters more in the life progression of a galaxy. "Is the evolution of a galaxy dominated by intrinsic properties such as total mass, or do wider-scale cosmic environments largely determine how galaxies grow and change?" Geach asked. "The role of the environment in influencing galactic evolution is one of the key questions of modern astrophysics."

The galaxies in the RCS2319 filament will eventually migrate toward the center of the emerging supercluster. Over the next seven to eight billion years, astronomers think RCS2319 will come to look like gargantuan superclusters in the local universe, like the nearby Coma cluster. These advanced clusters are chock-full of "red and dead" elliptical galaxies that contain aged, reddish stars instead of young ones.

Read more at Science Daily

200-Year-Old Shipwreck Found Off Gulf Coast

Ocean researchers exploring the depths of the Gulf of Mexico have discovered a wooden shipwreck laden with anchors, navigational instruments, glass bottles, ceramic plates, cannons and boxes of muskets.

Resting on the sea bottom in about 4,000 feet of water, some 200 miles offs the northern Gulf Coast shore, the wooden-hulled vessel "is believed to have sunk as long as 200 years ago," the U.S. National Oceanic and Atmospheric Administration (NOAA) said in a statement.

"Artifacts in and around the wreck and the hull's copper sheathing may date the vessel to the early to mid-19th century," said Jack Irion, a maritime archaeologist with the Interior Department's Bureau of Ocean Energy Management.

Originally identified as an "unknown sonar contact" during a 2011 oil and gas survey for Shell Oil Company, the shipwreck site was fully investigated in a recent NOAA-funded 56-day expedition in little known regions of the Gulf.

Scientists on board the NOAA Ship Okeanos Explorer used a state-of-the-art multibeam mapping sonar and a remote-controlled underwater explorer, Little Hercules, that is equipped with lights and high definition cameras. They were able to view a variety of artifacts inside the ship's hull.

While the ship's wood has nearly disintegrated after more than a century on the seafloor, the oxidized copper sheathing remains, along with a variety of artifacts.

"Some of the more datable objects include what appears to be a type of ceramic plate that was popular between 1800 and 1830, and a wide variety of glass bottles. A rare ship's stove on the site is one of only a handful of surviving examples in the world and the second one found on a shipwreck in the Gulf of Mexico," Irion said.

Historic events in the Gulf of Mexico that may have been responsible for the sinking include the War of 1812, events leading to the Texas Revolution, and the Mexican-American War.

Read more at Discovery News

Do Tarantulas Shoot Spidey Silk?

Tarantulas, like all spiders, extrude silk from so-called spinnerets on their abdomens, and scientists recently found evidence suggesting the arachnids also shoot silk from their feet, Spider-Man style. But these powers were fleeting, it seems, with new research showing tarantulas are not so like the famed superhero, after all.

The tips of their eight legs don't shoot out Spidey silk.

"The history of science has plenty of examples which teach us that our present truths are provisional," Fernando Pérez-Miles, an entomologist at the University of the Republic in Uruguay, told LiveScience in an email. "But in my opinion the present evidence shows that tarantulas do not produce silk by their feet."

To hold on to vertical surfaces, spiders rely on molecular forces generated by thousands of microscopic hairs on their feet. Additionally, tiny foot claws allow them to cling to rough surfaces. In 2006, a study led by biologist Stanislav Gorb suggested that the zebra tarantula uses silk fibers -- presumably produced by the nozzle-like spigots on their feet -- to help them climb up a vertical glass wall.

"I have been studying tarantulas for more than 30 years and I have never seen any signal of silk production by tarantula feet," Pérez-Miles said.

Pérez-Miles and his colleagues repeated Gorb's experiment in 2009, with one small alteration: They sealed the tarantula's silk-spinning abdominal organs (the spinnerets)with paraffin. They didn't see any silk residues left on the glass. Though, they did find that tarantulas normally brush their hind legs against unsealed spinnerets as they climb, suggesting that the silk Gorb found was produced by the arachnids' spinnerets, not their feet.

But that wasn't the end of the story. Last year, biologist Claire Rind and her students at the University of Newcastle in the U.K. placed various tarantulas on horizontal glass slides, which they then raised to a vertical position and gently shook. The spiders' legs slipped slightly, but they regained their footing quickly, each time leaving behind microscopic silk threads -- the team believes the arachnids only secrete silk from their feet as a lifeline to save themselves from falling, explaining why Pérez-Miles didn't see any silk in his experiments.

Next, to find the source of the foot silk, the researchers used an electron microscope to look at the feet of a dead tarantula. They found silk threads attached to ribbed, tapered structures that stuck out farther than the tiny foot hairs.

"But the microscopy was pretty poor," said arachnid specialist Rainer Foelix, author of "Biology of Spiders" (Oxford University Press, 2011). "There was such a low magnification of the silk threads that you couldn't tell them from a hole in the ground."

In a study published in April, Foelix and his colleagues compared the proposed foot spigots with spinneret spigots. They didn't look anything alike, but the foot structures strongly resembled the sensory hairs involved in taste and touch found elsewhere on the spiders. "Morphologically, it is very clear [the hairs] are sensory in nature," he said.

And in a study published in the May 15 issue of the Journal of Experimental Biology, Pérez-Miles repeated Rind's experiment, but again sealed the spider's spinnerets -- he didn't find any silk thread on the glass.

Read more at Discovery News

May 16, 2012

Colorful Butterflies Increase Their Odds of Survival by Sharing Traits

Bright black-and-red butterflies that flit across the sunlit edges of Amazonian rain forests are natural hedonists, and it does them good, according to genetic data published May 16 in the journal Nature.

An international consortium of researchers at UC Irvine and elsewhere discovered that different species of the Heliconius butterfly are crossbreeding to more quickly acquire superior wing colors. They also have a surprisingly large number of genes devoted to smell and taste.

The use of color to attract mates and fend off predators is widespread in daytime-loving butterflies, while night-flying moths are famous for having large antennae to sniff out potential mates' pheromones. Thus, researchers predicted that because they're such visual creatures, the butterflies would not be able to smell or taste very well.

"Instead, we learned that they have a rich repertoire of genes for olfaction [smell] and chemosensation [in this case taste]," said UCI biologist and article co-author Adriana Briscoe.

Delicate antennae contain smell receptors, she explained, and the butterflies' tiny feet hold taste buds.

Briscoe said additional findings by the consortium could help scientists better understand trait sharing in other species, such as Homo sapiens and Neanderthals.

As part of the international effort, researchers first sequenced the genome of the Postman butterfly (Heliconius melpomene), a well-known species whose caterpillars feast on passion fruit vines in the Peruvian Amazon. They then examined the genetic makeup of two closely related species -- Heliconius timareta and Heliconius elevatus -- all of which sport similar color patterns on their wings to ward off predators.

The genetic sharing among species, scientists believe, is the result of hybridization. Considered extremely rare, hybridization occurs when members of different species interbreed in the wild. Though often seen as an evolutionary dead end, hybrids are able to interbreed with other species, in the process introducing new genes that can help populations adapt to new or changing environments.

"What we show is that one butterfly species can gain its protective color pattern genes ready-made from a different species by interbreeding with it -- a much faster process than having to evolve one's color patterns from scratch," said co-author Kanchon Dasmahapatra, a postdoctoral researcher at University College London.

The paper was produced by researchers in the U.S., Central America, South America and Great Britain -- dubbed the Heliconius Genome Consortium -- who took on the task of sequencing the butterfly's genome, consisting of about 295 million DNA base pairs.

Read more at Science Daily

Robot Arm Knows What You Want

Scientists have invented a device that allows paralyzed patients to control a robot arm directly from their brain, bypassing their damaged central nervous system.

This brainwave-connected device would then be able to grab objects that the user wants. The system uses tiny electrodes implanted directly into the primary motor cortex, the part of the brain that controls movement. Signals are then routed through a tiny box in the scalp, which is then connected by wire to a small refrigerator-size computer. The computer then translates the brain movement patterns into an algorithm that can be transmitted directly to the robot arm.

“The ultimate goal is to develop neural technologies to restore mobility specifically for people with no control of their arms or hands,” said Leigh Hochberg, a neurologist at the Department of Veterans Affairs in Providence, R.I., who also has appointments at Massachusetts General Hospital, Brown University and Harvard University. “We’re hoping to provide technology directly from brain signals back to commands that control assisted devices or limbs.”

Hochberg and John Donoghue, director of the Brain Institute at Brown, had previously collaborated on the “BrainGate” project that produced the 2006 study showing how a patient could control a computer cursor using a brain-to-computer neural interface. Their latest study, which appears in today’s issue of the British science journal Nature, goes a step further. It is, in effect, developing a separate neural pathway to deliver messages from the brain to an arm, in this case an artificial one.

Hochberg said the experiment has worked with two patients, a man and a woman who both lost the use of their limbs and their voice as a result of a stroke.

Both patients were able to move the robot arm to grab foam balls. And the woman was able to pick up a metal coffee container and drink through a straw for the first time since she was injured 15 years earlier.

“The smile on her face was something I and our research team will never forget,” Hochberg said.

The researchers cautioned that the efforts with the two patients only worked successfully about two-thirds of the time, and are not as fast or accurate as a human arm. The experiment does give hope to millions of patients who have become paralyzed as the result of stroke or other physical trauma.

Researchers implanted an array of electrodes the size of a baby aspirin near the top of the motor cortex. From their, 96 hair-thin electrodes pick up signals and send them to a penny-sized device in the top of the scalp. A matchbox-sized transmitter on top of the head then relays the brain signals to the computer which controls the robot arm.

Each neuron is like a radio broadcast tower putting out signals that generates a pattern, Donohue said.

“It’s like a QR code coming out at all times. The computer takes that pattern and translates it into a command that moves it to the left or right."

Read more at Discovery News

Superflares Found on Sun-like Stars

Scientists have found superflares more than 1 million times more powerful than flares generated by the sun occurring on sun-like stars being studied by NASA's Kepler space telescope.

The finding, culled from 120 days of observations of 83,000 stars, is the first to detail how often and how energetic flares on other stars can be.

The discovery, however, raises a question about how the massive outbursts, believed to be caused by complex magnetic interactions, can physically occur.

Scientists previously theorized a close-flying Jupiter-sized planet would be needed to ground a super-flaring stars' magnetic fits. For the size flares our sun experiences, magnetic reconnection occurs within the sun itself, with one twisted magnetic field snapping and then linking up to another -- releasing energy in the process as a solar flare.

But the 365 superflares found by scientists crunching Kepler data need another explanation, said astrophysicist Bradley Schaefer, with Louisiana State University.

Kepler, whose prime mission is to look for planets transiting the face of their parent stars, should have found big, close-by planets (so-called "hot-Jupiters") circling about 10 percent of the superflaring stars. Instead the team, led by Kyoto University astronomer Hiroyuki Maehara, found none.

"Maehara's point that the 365 superflares don't show hot-Jupiters is a pretty strong argument against the hot-Jupiter theory," Schaefer told Discovery News. "No one has proposed any alternative."

Maehara thinks they could be caused by starspots much larger than any sunspot found on the sun.

"However it is not well understood why and how such large starspots are formed on solar-type stars," he wrote in an email to Discovery News.

"This very much is a mystery and a challenge for classic astrophysics," Schaefer said.

Scientists don't believe our sun has ever generated such a superflare. If one had, it likely would have triggered enough chemical change in the atmosphere to set off a mass-extinction of life on Earth. The only mass extinctions in geologic record have been tied to asteroid strikes, volcanic activity and related climatic change.

Read more at Discovery News

Ancient 'Loch Ness Monster' Suffered Arthritis

Ancient creatures resembling stout-necked Loch Ness Monsters apparently developed arthritis in their monster jaws, revealing that even such lethal killers could suffer from and eventually succumb to diseases of old age, researchers find.

Scientists reached that conclusion while investigating the fossil of an extinct marine reptile known as a pliosaur. The carnivore was apparently an old female extending some 26 feet (8 meters). It had a 10-foot-long (3 meters), crocodilelike head, short neck, whalelike body and four powerful flippers to propel it through water to hunt down prey.

"This pliosaur, like many of its relatives, was truly huge," researcher Michael Benton, a vertebrate paleontologist at the University of Bristol in England, told LiveScience. "To stand beside its skull and realize that it is 3 meters long, and massive and heavy as it is, that it once functioned with muscles and blood vessels and nerves, is amazing. You can lie down inside its mouth."

Normally, with huge jaws and teeth about 8 inches (20 centimeters) long, this pliosaur could have ripped most other animals apart. However, paleontologists found this specimen was apparently afflicted with an arthritis-like disease.

Old lady pliosaur

Benton and his colleagues analyzed an approximately 150-million-year-old specimen of Pliosaurus that had been unearthed in 1994 by fossil collector Simon Carpenter and held since then in the Bristol City Museum and Art Gallery in England.

The beast would have lived in what is now southern England, back when the area was covered in warm, shallow seas. "Imagine the Mediterranean or Florida," Benton said. Other fossils from the site include smaller marine reptiles such as marine crocodiles, turtles and plesiosaurs, other Loch Ness Monster-like creatures upon which the pliosaur likely fed, as well as fish and shellfish.

The skeleton had a low ridge of bone running from front to back on top of its skull. Investigators regarded it as female because males were thought to have taller ridges. Its large size and fused skull bones suggested maturity. The investigators noticed the reptile had signs of a degenerative condition similar to human arthritis.

"The most exciting aspect of this research for me is the arthritic condition, which has never been seen before in these or similar Mesozoic reptiles," researcher Judyth Sassoon at the University of Bristol told LiveScience.

Crooked jaws

The degenerative condition had eroded the pliosaur's left jaw joint. This would have knocked its lower jaw askew.

"In the same way that aging humans develop arthritic hips, this old lady developed an arthritic jaw and survived with her disability for some time," Sassoon said. "But an unhealed fracture on the jaw indicates that at some time the jaw weakened and eventually broke.

"With a broken jaw, the pliosaur would not have been able to feed, and that final accident probably led to her demise."

Marks on the lower jawbone from the pliosaur's upper teeth suggest the predator lived with a crooked jaw for many years, long enough to damage its own bones.

"You can see these kinds of deformities in living animals, such as crocodiles or sperm whales, and these animals can survive for years as long as they are still able to feed. But it must be painful," Benton said. "Remember that the fictional whale Moby-Dick, from Herman Melville's novel, was supposed to have had a crooked jaw."

Read more at Discovery News

May 15, 2012

Chronic Child Abuse Strong Indicator of Negative Adult Experiences

Child abuse or neglect are strong predictors of major health and emotional problems, but little is known about how the chronicity of the maltreatment may increase future harm apart from other risk factors in a child's life.

In a new study published in the current issue of the journal Pediatrics, Melissa Jonson-Reid, PhD, child welfare expert and a professor at the Brown School at Washington University in St. Louis, looked at how chronic maltreatment impacted the future health and behavior of children and adults.

The study tracked children by number of child maltreatment reports (zero to four or more) and followed the children into early adulthood, by which time some of the children had become parents.

The study sought to determine how well the number of child maltreatment reports predicted poor outcomes in adolescence, such as delinquency, substance abuse in the teen years or getting a sexually transmitted disease.

"For every measure studied, a more chronic history of child maltreatment reports was powerfully predictive of worse outcomes," Jonson-Reid says.

"For most outcomes, having a single maltreatment report put children at a 20 percent to 50 percent higher risk than non-maltreated comparison children.

In addition, a series of adult outcomes were tracked to see if the chronicity of maltreatment still mattered after controlling for the poor outcomes in adolescence. Adult outcomes included adult substance abuse or growing up and having children whom they then maltreated.

"In models of adult outcomes, children with four or more reports were about least twice as likely to later abuse their own children and have contact with the mental health system, even when controlling for the negative outcomes during adolescence." Jonson-Reid says that there appears to be good reason to put resources into preventing ongoing maltreatment.

"Successfully interrupting chronic child maltreatment may well reduce risk of a wide range of other costly child and adolescent health and behavioral problems," she says.

Jonson-Reid cites a recently published Centers for Disease Control and Prevention study estimating lifetime costs for a single year's worth of children reported for maltreatment at $242 billion.

"What our study illustrates is that these costs are even more likely to accrue for children who continue to be re-reported," she says.

The study also found that maltreatment predicts a range of negative adolescent outcomes, and those adolescent outcomes then predict poor adult outcomes.

"If the poor outcomes in adolescence can be dealt with effectively, then later adult outcomes may also be forestalled," Jonson-Reid says.

"Our findings could therefore be interpreted as supporting many current evidence-based interventions that seek to improve behavioral and social functioning among children and adolescents who have experienced trauma like abuse or neglect."

Read more at Science Daily

Chinese Physicists Smash Quantum Teleportation Record

A group of Chinese engineers have smashed the records for quantum teleportation, by creating a pair of entangled photons over a distance of almost 100 kilometers.

Quantum entanglement is the mysterious phenomenon where two particles become tightly intertwined and behave as one system — whether they are next to each other on a laboratory bench, or either sides of a galaxy.

If you examine one particle and measure a certain property — say, vertical polarization — then the other will instantly adopt the opposite property — in this case, horizontal polarization.

It’s crazy stuff. Albert Einstein described it as “spooky action at a distance,” when he was still struggling to get his brain around the ideas proposed by quantum theory. But it’s a powerful phenomenon, and one that physicists have long attempted to harness in the lab.

Trouble is, creating a pair of particles with any distance between them has always been a difficult hurdle to overcome. Imperfections in optic fiber glass, or air turbulence, means that the qubits become unentangled. Plus as the distance gets farther your beam gets wider, so photons simply miss their target.

Juan Yin at the University of Science and Technology of China in Shanghai claims to have cracked it. His team sent photons between two stations, separated by 97 km. Over a Chinese lake, to be precise. To pull off this feat, Yun and friends used a 1.3 Watt laser, and a clever optic steering technique to keep the beam precisely on target. With this setup, they were able to teleport more than 1,100 photons in four hours, over a distance of 97 kilometers.

The last quantum teleportation record was 16 km, and was set by a different set of Chinese researchers in 2010.

Read more at Wired Science

Beheading: Once a Nobleman's Death

When most people think of beheadings they probably think of events far away in time and place, such as Marie Antoinette's 1793 guillotine execution during the French revolution.

But beheadings are hardly a thing of the past; in fact in some places they are becoming increasingly commonplace.

Though most Americans are unaware of it, many beheadings take place very near the United States, in Mexico. As Will Grant noted in a BBC News story,

    This month has been perhaps the worst in terms of decapitations. In the past 10 days alone, there have been an unprecedented 81 beheaded bodies discovered in the country. In early May, 14 decapitated bodies were found in Nuevo Laredo, just over the border from Texas. Last week, 18 bodies and severed heads were left in two mini-vans near Lake Chapala, an area popular with tourists in western Mexico. Finally, in one of the most shocking incidents of its kind since the current drug war began, 49 headless and mutilated bodies were left in plastic bags on a road outside the industrial city of Monterrey.

The idea of execution by decapitation is bizarre and horrific, though for millennia public beheadings around the world were fairly common. It's only in modern times that cutting a person's head off has come to be considered barbaric.

In centuries past beheading was actually preferable to other common forms of execution (such as being burned alive or disemboweled). In early England beheading was considered a noble, and even honorable, death. Nigel Cawthorne, author of "Public Executions" (2006, Capella Press) notes that "Hanging was usually reserved for the lower classes.

Rebellious noblemen who had been sentenced to be hanged, drawn and quartered for treason were understandably relieved when their sentence was changed to beheading...knowing that they could make a parting speech before departing this life in a relatively swift and painless manner."

Beheading remains an officially sanctioned method of execution in several Middle Eastern countries.

Though historically decapitation was essentially a means to an end, the beheading element itself carried a powerful message, and continues to do so today. There are far cleaner and less gruesome ways to kill a person, but few things make a greater impression on the public than seeing a severed head. That shock value is used to strike fear in enemies and ensure obedience.

In October 2010, an American businessman on vacation with his wife at Texas's Falcon Lake bordering Mexico was killed by suspected drug runners. The Mexican police chief investigating his death was himself murdered and decapitated; his severed head was found inside a suitcase.

According to a Oct. 13, 2010 dispatch from Fred Burton, Vice President of Intelligence at the Stratford Global Initiative think tank, "The Zeta cartel boss responsible for the beheading of the Mexican investigator sent a strong signal to the Mexican authorities that this is his geography, this is Zeta controlled area, and for the Mexican government to stay out."

Read more at Discovery News

Dino-Era Insects Frozen in Time During Oldest Pollination

With massive dinosaurs towering above, tiny female insects called thrips had just dusted themselves with hundreds of pollen grains from a gingko tree more than 100 million years ago when they perished, only to be preserved in tree resin called amber.

The discovery, detailed this week in the journal Proceedings of the National Academy of Sciences, is the oldest known record of insect pollination.

(Pollination occurs when either the wind or an animal, mostly insects, deliver pollen from a plant's male reproductive organ to the female parts either on the same plant or another one.)

During the lower Cretaceous Period when the newly discovered thrips lived, flowering plants would have just started to diversify, eventually replacing conifers as the dominant species, the researchers said.

"This is the oldest direct evidence for pollination, and the only one from the age of the dinosaurs," study researcher Carmen Soriano said in a statement. "The co-evolution of flowering plants and insects, thanks to pollination, is a great evolutionary success story."

Soriano and an international team of scientists studying the two pieces of amber, which were discovered in what is now northern Spain, say the specimens date back between 110 million and 105 million years ago.

They found six female thrips, also called thysanopterans, enclosed in the amber, with hundreds of pollen grains attached to their tiny bodies — the insects are just 2 millimeters long. The thrips, the researchers found, belong to a new genus now named Gymnopollisthrips, with two new species, G. minor and G. major.

After the amber pieces' initial discovery, they were then kept in a collection of the Museo de Ciencias Naturales de Álava in Spain.

To get a closer look at the pollination event frozen in time, the team used synchrotron X-ray tomography at the European Synchrotron Radiation Facility (ESRF), focusing on the most representative of the amber-encapsulated thrips. In synchrotron X-ray tomography, charged particles are sent speeding through magnetic fields; these particles release high-energy light that can then pierce opaque materials to reveal three-dimensional, high-resolution images.

The images revealed various features of the pollen grains, together suggesting the grains came from a kind of cycad, or gingko, tree, the researchers said. Gingkos have separate male and female trees, with males producing small pollen cones and females bearing ovules at the ends of stalks that develop into seeds after pollination.

Read more at Discovery News

May 14, 2012

Killer 'Hot Jupiters' Could Abort Formation of Alien Earths

This December, Jupiter will rival the brilliance of Venus in the night sky as Earth makes its closest approach to the giant planet for this year (no doubt 2012 soothsayers will mistake it for the final approach of the mythological doomsday planet Nibiru).

December's "Christmas Star" appearance of Jupiter will belie the fact that this monster, 318 times the mass of Earth, had the potential to snuff-out Earth's formation 4.5 billion years ago.

That's the conclusion from a new analysis of the NASA Kepler space telescope survey of planets orbiting other stars. A team of astronomers searched the Kepler data for any Earth-sized planets cohabiting in systems with "hot Jupiter" class planets.

The so-called "hot Jupiters" are so close to their stars they complete and orbit within a matter of days (Jupiter takes 12 years). The only way they could have gotten that close to their star was to somehow migrate from a much farther out frigid planetary "construction shipyard" where ices and lightweight gasses could condense onto a solid body.

Kepler can't photograph planets, but it measures the very slight dimming of a star when a planet in an edge-on orbit passes in front of the star. We'll be treated to such an event this Jun. 5-6, when Venus makes a rare transit across the face of our sun.

Looking at 63 candidate hot Jupiter systems in the Kepler data, the research team did not find any evidence for small companion terrestrial planets. The hot Jupiters complete an orbit so quickly that astronomers can look for irregularities in the timing of the transits -- known as transit timing variations, or TTVs -- that would be telltale evidence for the pull of smaller, unseen bodies.

But no TTVs were detected. The absence of small, Earth-sized worlds near hot-Jupiters suggests the migration of the hot Jupiter planet prevented or aborted the formation of smaller terrestrial planets.

The team, led by Jason Steffen of the Fermilab Center for particle Astrophysics, published their results in the May 7 edition of Proceedings of the National Academy of Sciences.

Odds of finding a smaller companion planet got a little better when researchers expanded the search to include systems with close-orbiting "hot Neptunes" of around 15 Earth masses. Of the 222 hot Neptunes in the Kepler database, there were two with possible companions that changed the transit timing of the giant planets' orbits.

The team also looked at so-called "warm Jupiters" that migrate not as close to the star as hot Jupiters. They had about a ten percent chance of companion planets.

These results suggest that the hot Neptunes and warm Jupiters had a markedly different formation history from the hot Jupiters.

In our solar system, there is a growing body of evidence that suggests there was a lot of planet migration in our early planetary history. The giant outer planets moved, well, outward.

This shoveled icy bodies outward to form the Kuiper belt, where Pluto dwells. What's more, Jupiter's gravitational influence formed the asteroid belt by keeping this primordial debris from agglomerating into an Earth-sized planet -- as dramatically demonstrated last week by a detailed analysis of the mini-planet/asteroid Vesta from NASA's Dawn mission.

If Jupiter's orbit was more elliptical, the asteroid belt would extend all the way through the area of the inner solar system and Earth would be a bunch of debris, like the blown-up planet Alderaan in the Star Wars trilogy (though Earth would have not formed in the first place).

Read more at Discovery News

Europe's Early Man Drew Female Sex Organs, Animals

Multiple engraved and painted images of female sexual organs, animals and geometric figures discovered in southern France are believed to be the first known wall art.

Radiocarbon dating of the engravings, described in the latest Proceedings of the National Academy of Sciences, reveals that the art was created 37,000 years ago. This makes them slightly older than the world’s earliest known cave art, found in Chauvet Cave, southeastern France.

Since this site, Abri Castanet in southern France, is very close to Chauvet, it is likely that the artists in both cases came from what is known as the Aurignacian culture, which existed until about 28,000 years ago.

“Abri Castanet has long been recognized as one of the oldest sites in Eurasia with evidence for human symbolism in the form of hundreds of personal ornaments (such as) pierced animal teeth, pierced shells, ivory and soapstone beads, engravings and paintings on limestone slabs,” lead author Randall White told Discovery News.

White, a New York University anthropology professor, added that the artwork “is associated with members of some of the first modern human populations to leave Africa, dispersing into Eurasia, replacing the preceding Neanderthals.”

White and his international team analyzed the engravings, which were made with ochre on a 3,307-pound block of limestone found in a rock shelter occupied by a group of Aurignacian reindeer hunters. The researchers believe the limestone was once the shelter’s low ceiling, which later collapsed.

The engravings include depictions of “the back end of a horse,” according to the researchers, as well as multiple images of the female vulva. Other “zoomorphic” and “geometric” engravings are included, along with additional images of female sexual organs.

Unlike the Chauvet paintings and engravings, which are deep underground and away from living areas, “the engravings and paintings at Castanet are directly associated with everyday life, given their proximity to tools, fireplaces, bone and antler tool production, and ornament workshops,” White said.

The discovery in many respects leads to more questions than answers, given the subject matter of the artwork.

“While there are animal figures, the dominant motif is that considered to represent abstract female vulvas,” White said, mentioning that other interpretations could be possible.

Additional Aurignacian artwork, however, clearly represents female sexual organs. The Venus of Hohle Fels, for example, is an ivory figurine dating to at least 35,000 to 40,000 years ago, according to Nicholas Conard, a paleoanthropologist at the University of Tübingen who reported the find.

The figurine, found in a southwestern Germany cave, depicts a woman with what Conard told Discovery News were “large projecting breasts” and a pronounced vulva and labia majora visible between the woman’s open legs.

Read more at Discovery News

Lucky Strike: Lightning Brings Seismic Surprise

As dark clouds rolled in from the west on a July afternoon last year, Klaus-G. Hinzen, a seismologist at the University of Cologne in Germany, knew a big storm was brewing. He was watching from the window of the university's earthquake observatory in Bensberg, a small town outside of Cologne, as lightning struck a nearby hotel. Less than a minute later, a flash took out a tree next to the earthquake lab itself, turning that stormy afternoon into a rare seismic experiment.

"The main experience that we seismologists have with lightning strikes is a very bad one, because it often causes a lot of damage in the equipment. But the equipment didn't fail this time," Hinzen told OurAmazingPlanet. "It's a rare instance that you have a lightning strike so close to so many different seismometers and get a complete record of it."

Hinzen's seismic equipment recorded the lightning strike and its effects in shocking detail.

Anatomy of a lightning strike

When the bolt struck the big poplar tree that stood 174 feet (53 meters) from the lab, one of Hinzen's seismometers — a type of accelerometer called a strong-motion station, specifically tuned to pick up small ground movements — recorded a strong signal that lasted about one-tenth of a second.

The strong-motion station detected another spike a fraction of a second later, which Hinzen interprets as the thunderclap that accompanied the lightning. Then the 65-foot (20 meters) tree exploded, scattering debris in a 65-foot radius, and the station recorded a third set of ground shakes.

"We think the current flowing through the tree heated the sap in the trunk so quickly that it turned into steam," Hinzen said. "This put enough pressure on the trunk that the tree basically exploded."

The fourth and final seismic signal came about two-tenths of a second later, when the high-pressure airwave from the exploding tree shook the ground near the strong-motion station. This airwave had moved slower than the ground wave from the explosion, Hinzen explained, because it was traveling through air instead of rock.

Altogether, from the lightning strike to the fallout from the tree explosion, the incident lasted less than half a second.

A lucky strike

Hinzen was able to tease out these short-lived signals because the strong-motion station took very detailed measurements — 250 readings every second.

"Lightning looks very different on a seismometer because the total signal we see is very short compared to the ground motion you would see from a true earthquake," Hinzen said. "Before this, I would not have guessed we could resolve these very fast signals."

Another important factor was the earthquake observatory's advanced lightning protection system, which had been installed just a few years earlier. Without it, Hinzen said, the lightning would have fried the equipment that collected and stored the data.

All in all, it turned out to be a lucky strike for Hinzen.

"It's just such a rare occurrence that it hit where we could record it," he said, "and it really shows how well these systems can perform."

Read more at Discovery News

Free-floating Planets Could Harbor Life

Our galaxy could have as many as a hundred thousand billion life-carrying Earth-sized planets floating between the stars, according to a new study.

An international team of scientists led by Professor Chandra Wickramasinghe, of the University of Buckingham, published their finding in the journal Astrophysics and Space Science.

Recent estimates have suggested that our galaxy has as many planets as stars -- approximately 200 billion - with most of those planets not orbiting a star. But this latest study dramatically increases the number of 'free-floating' planets.

Wickramasinghe and colleagues propose that these planets originated in the early universe a few million years after the Big Bang, and that they make up most of the so-called "missing mass" of galaxies, known as dark matter.

They calculate that on average our solar system would be visited by a free-floating planet once every 26 million years. As each one passes by our solar system, it accumulates up to 1000 tonnes of interplanetary dust onto its surface.

"If the dust included microbial material that originated on Earth ... this process offers a way by which evolved genes from Earth life could become dispersed through the galaxy," they write.

Dr Simon O'Toole, an astronomer at the Australian Astronomical Observatory, isn't convinced the number of free-floating planets is so high.

"It's a fascinating idea, but involves too many assumptions to say for sure that it's going to be real," says O'Toole.

Read more at Discovery News

May 13, 2012

New Ultra-Thin Electronic Films Have Greater Capacity

The development of a new combination of polymers associating sugars with oil-based macromolecules makes it possible to design ultra-thin films capable of self-organization with a 5-nanometer resolution. This opens up new horizons for increasing the capacity of hard discs and the speed of microprocessors.

The result of a French-American collaboration spearheaded by the Centre de Recherches sur les Macromolécules Végétales (CNRS), this work has led to the filing of two patents. It is published in the journal ACS Nano. This new class of thin films based on hybrid copolymers could give rise to numerous applications in flexible electronics, in areas as diverse as nanolithography, biosensors and photovoltaic cells.

Before new generations of microprocessors can be devised, an evolution in lithography, the technique used for printing electronic circuits, is indispensable. Until now, the thin films used in electronic circuits have been designed from synthetic polymers exclusively derived from petroleum. However, these thin films have limitations: their minimum structural resolution is around 20 nanometers and cannot be reduced further by combining petroleum-derived polymers. This limit has been one of the main obstacles to the development of new generations of very-high-resolution flexible electronic devices.

Why was there such a limit? Because of the low incompatibility between the two blocks of polymers, both derived from oil. For that reason, the team headed by Redouane Borsali, CNRS senior researcher at the Centre de Recherches sur les Macromolécules Végétales (CERMAV), came up with a hybrid material: this new class of thin films combines sugar-based and petroleum-derived (silicon containing polystyrene) polymers with widely different physical/chemical characteristics. This copolymer(1), formed of highly incompatible elementary building blocks, is similar to an oil bubble attached to a small water bubble. The researchers have shown that this type of structure is capable of organizing itself into sugar cylinders within a petroleum-based polymer lattice, each structure having a size of 5 nanometers, i.e. much smaller than the resolution of "old" copolymers, exclusively composed of petroleum derivatives. In addition, this new generation of material is made from an abundant, renewable and biodegradable resource: sugar.

Achieving this performance makes it possible to envisage numerous applications in flexible electronics: miniaturization of circuit lithography, six-fold increase in information storage capacity (flash memories -- USB keys -- no longer limited to 1 Tbit of data but 6 Tbit), enhanced performance of photovoltaic cells, biosensors, etc. The researchers are now seeking to improve control of these nano-glycofilms' large-scale organization and design in different self-organized structures.

Read more at Science Daily

Parenting Lessons from the Ancient World

Mothers' Day might be a relatively new holiday, but that doesn't mean that parents today are any more deserving of adulation in the form of flowers and gift cards than their counterparts in the ancient world.

No matter in what ancient civilization parents raised their children, they faced a lot of the same challenges. And any advice from those early Imperial China or ancient Mesopotamian mothers could even still apply today.

Ancient Rome

Although the history of ancient Rome conjures up images of marching armies conquering new territory, ambitious emperors seizing power and bloodthirsty gladiators dueling in the area, parents were still responsible for the somewhat more mundane task of raising children. For parents in the lower classes in ancient Rome, a well raised child could be a means for them to change their fortunes, assuming the investment in that child's care paid off.

Quintus Sulpicius Maximus was an 11-year-old boy who lived during the first century in ancient Rome. The son of former slaves, Quintus had a knack for Greek poetry, a talent that was encouraged by his parents. But before Quintus had a chance to potentially be the next Ovid, he died in 94 A.D. According to a statue left by his grieving parents, the cause of death was working too hard.

The moral of the story? Don't push your children too hard.

Ancient China

If there's one person from the ancient world who you could turn to for advice on just about anything, it would be the now legendary philosopher Confucius. Even with all the time Confucius spent teaching students and nobility his beliefs on morality, justice, politics and more, he still was able to spare a few moments to impart some parenting advice.

According to Georgetown University assistant professor of theology Erin Cline, early Confucians understood, like modern parents, that the earliest years of a child's life could fundamentally inform the person he or she grew up to be as an adult. A nurturing parent can be the most important early experience in a child's life.

Like any other topic in which Confucius gave advice, his advice on parenting can be wrapped within in a parable. In one such story, Zengzi, one of Confucius' students, explains to his wife, who had recently enticed their son to behave with promises of a slaughtered pig, that by deceiving the child to get her way, she has both taught him to lie and not to trust what his mother says.

Ancient Egypt

Unlike parents of other cultures who seemed to prepare their children for the life ahead, ancient Egyptians almost seemed to prepare their children for death.

As explained in the book "Egypt and the Egyptians," young men and women were essentially raised to take over for their parents when they became elderly, a relatively short period of time given ancient Egyptian men in peasant society had an average lifespan on 33 years and women on average only made it to 29. Formal education was generally lacking, so most children learned about morality, religion and more at the home.

And unlike ancient Rome and other societies at the time which were patriarchal, ancient Egyptians passed their inheritance on equally to both sons and daughters within a family. However, the eldest son was responsible for the costly and critical task of conducting the burial rights for his parents.

Read more at Discovery News