Blogs / 80beats

A thrilling set of ancient crocodile fossils have been unearthed in northern Africa. A “saber-toothed cat in armor” and a pancake-shaped predator are among the strange crocodile cousins whose bones have been found beneath the windswept dunes of the Sahara, archaeologists say [National Geographic News].

At a news conference organized by the National Geographic Society, which sponsored the research, scientists announced that the fossils represent 5 species; 3 new species and 2 that were previously known. These ancient croc ancestors, known as crocodilyforms, are unlike any crocodiles encountered in the Northern Hemisphere, according to the research team. Their findings are detailed in the journal ZooKeys.

The crocs were spectacularly diverse, and included a species that ate dinosaurs, two that grew up to 20 feet long, and two that had long legs for quick movement on land but also had long tails for swimming. The three new species are:

• BoarCroc (Kaprosuchus saharicus), a 20-foot meat-eater. It used its snout for ramming and three sets of dagger-shaped fangs for slicing dinosaurs it ate.

• PancakeCroc (Laganosuchus thaumastos): a 20-foot-long, squat fish-eater with a 3-foot long flat head with spike-shaped teeth.

• RatCroc (Araripesuchus rattoides), a 3-foot-long plant and grub eater with buckteeth used for digging [Chicago Sun-Times].

The two previously known species are nicknamed DuckCroc, a three-foot long, long-legged croc that feasted on fish and frogs, and DogCroc, another small and lanky croc that mostly ate plants and grubs.

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Proceedings of the National Academy of Sciences, November 17
When is a goat like a reptile? When it’s cold-blooded, slow-moving, and fond of sitting on warm rocks. Researchers have discovered a bizarre dwarf goat species that lived on the Spanish island Majorca, but that went extinct when human hunters arrived on the island about 3,000 years ago. The study says that the goat’s cold-blooded ways allowed it to survive on the resource-scarce island, as it could match its growth and metabolism to the available food supplies, but its sluggish movements made it easy prey for humans. In medical news, a research team investigating the dramatic failure of an HIV vaccine trial, in which vaccinated people seemed to be at higher risk of infection, has proposed a new theory for the failure. The study suggests that the common cold virus, which was used in the vaccine to carry HIV material around the body so the immune system could learn to recognize HIV, may have been at fault. The vaccine didn’t cause infection. But for people who have previously been exposed to this cold virus, its appearance may have triggered a gathering of  immune cells called CD4 T-cells which were ready to fight it off. But those are the cells that HIV infects, so if people were then exposed to the HIV virus, the virus would have been presented with a ready availability of targets. Finally, an interesting study captured a snapshot of evolution-in-action on the Galapagos islands. A husband and wife team of evolutionary biologists is documenting what appears to be the emergence of a new species among Galapagos finches, the same birds that inspired Charles Darwin’s theory of evolution.

New England Journal of Medicine, November 19
Who can resist a story about brain-eaters that also has valuable medical and evolutionary lessons? A NEJM study describes a tribe in Papua New Guinea that used to engage in ritualistic cannibalism; when a member of the tribe died, the others ate the person’s brain as a mark of respect. The practice became a problem in the early 20th century, when some people became infected with a disease similar to mad cow disease and its human variant, Creutzfeldt Jakob disease. These fatal diseases are caused by misfolded proteins in the brain, so when the Fore people of Papua New Guinea consumed an affected brain the disease quickly spread. But a new study of living Fore people revealed that many are immune to the disease, which suggests that evolution has been acting quickly: Those people who had no resistance to the disease died off quickly, while people with resistance lived and multiplied. Researchers also hope to study the Fore people for clues on how to treat or prevent such diseases.

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Feel like teaching a lesson to that pinhead-sized worm that’s been bothering you? According to a study in the Journal of the American Chemical Society, a  material called dithienylethene plus a blast of UV light can stop a worm in the midst of its worming, rendering it temporarily paralyzed.

The researchers fed a light-sensitive material — a “photoswitch” known as dithienylethene — to the transparent worms. When exposed to ultraviolet rays, the molecule turned blue and the worms became paralyzed. Using visible light instead made the chemical turn colorless and the paralysis ended [LiveScience]. Scientists aren’t sure why the transparent nematodes became paralyzed, but they know dithienylethene changes shapes and suspect it interferes with the worm’s energy-producing metabolic pathways. Repeated cycles of UV-induced paralysis actually killed some of the worms.

Unsurprisingly, news of this worm stun-gun led to longing for Star Trek-style phasers, and the scientists, though skeptical, were good sports about it. As lead researcher Neil Branda said tactfully: “I’m not convinced there’s a legitimate use of turning organisms on and off in terms of paralysis, but until somebody tells me otherwise, I’m not going to say that there isn’t an application” [BBC News].

But while phasers remain a fantasy, light-activated materials certainly have a future in medical research. Light-activated drugs could be used to activate tumour-killing drugs once they reach a particular location in the body. Similar chemicals have been used before, but have required a steady supply of light – often harmful UV bandwidths – to stay active. The new compounds, known as diarylethenes, could be more useful because they can be switched on and off with a single light pulse, Branda says [New Scientist].

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Image: Wiki Commons / Yonatanh

An artificial brain as powerful as a human’s remains a distant goal, but scientists are inching closer. This week IBM announced that by using a brain-simulating algorithm called BlueMatter, researchers created an artificial brain simulation that packs more brainpower than a cat.

Researchers used an IBM supercomputer at the Lawrence Livermore Lab to model the movement of data through a structure with 1 billion neurons and 10 trillion synapses, which allowed them to see how information “percolates” through a system that’s comparable to a feline cerebral cortex [San Jose Mercury News]. The team’s previous effort two years ago, modeled after a rat brain, simulated only about 55 million neurons.

The staggering surge in computing power has engineers like IBM’s Dharmendra Modha drooling over the possibilities for more brain-like computers. By reverse engineering [the] cortical structure, Modha says, researchers could give machines the ability to interpret biological senses such as sight, hearing and touch. And artificial machine brains could process, intelligently, senses that don’t currently exist in the natural world, such as radar and laser range-finding [Popular Mechanics].

It should come as no surprise that the design suggests such military applications, as DARPA provided much of the funding. But like the Internet and other technologies originally developed for the military, BlueMatter’s abilities could lead in a multitude of directions. “As our digital and physical worlds collide, there is a tsunami of information,” Modha said. “There is a need for a new kind of intelligence that can sort through, prioritize and extract the most important information, much like how the brain deals with sight, sounds, tastes, touch and smell” [San Jose Mercury News].

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Image: IBM Almaden research lab, Stanford University

A fungus found within ancient mammoth dung is providing scientists with clues about how the large ancient mammals collectively known as megafauna went extinct. The fungus, Sporormiella, produces spores in the dung of large herbivores. These are then preserved in the layers of mud and can provide an index of the number of these animals, or megafauna, that roamed the environment at a particular time [BBC News]. For a new study, researcher Jacquelyn Gill collected and analyzed spores in sediment samples from an Indiana lake and several sites in New York.

From Gill’s analysis, published in the journal Science, she concluded that North American megafauna began a slow decline around 15,000 years ago and vanished about 1,000 years later. The data suggests megafauna started going extinct much earlier than previously though, which basically wipes out two theories of their extinction.

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Members of a tribe in Papua New Guinea has evolved resistance to a affliction similar to mad cow disease (called Creutzfeldt Jakob disease, or CJD, in people). How did they do it? Cannibalism, according to a study in the New England Journal of Medicine.

The Papua New Guinea variant is called kuru, and it was a disaster there. When members of the Fore people in Papua New Guinea died, others would eat the dead person’s brain during funeral rituals as a mark of respect. Kuru passed on in this way killed at least 2500 Fore in the 20th century until the cause was identified in the late 1950s and the practice halted [New Scientist].

The scientists compared DNA samples of about 3,000 living Fore people, some of whom had participated in the old rituals, to 152 samples of stored DNA from Fore that kuru killed. They looked at the genes for prions, ordinary brain proteins that take on a misfolded shape in prion disease such as CJD and kuru. They found a mutation called G127V that protected people from kuru. Only people who ate brains and survived have it, they found [Reuters].

The discovery excited scientists with the possibility of understanding and even treating other prion diseases, like CJD. And British neurologist John Hardy exemplified the scientific glee at seeing human evolution happen in such a short time. “It’s fantastic demonstration of natural selection… In Papua New Guinea kuru became the major cause of death, so there was a clear survival advantage and the selection pressure was enormous” [BBC News].

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Image: D. Carleton Gajdusek

With NASA’s manned space flight program in tumult, it’s an open question when/if human boots will tramp on Martian soil. But the space agency has provided a virtual way for humans to explore the red planet, with its new “Be a Martian” program.

The online project, a collaboration between NASA and Microsoft, enlists the power of crowdsourcing. Users are invited to sort through the hundreds of thousands of photos of Mars that have been sent back by rovers and orbiters. To convince people to spend hours pouring over pictures of dusty Martian landscapes, two tasks have been set up as games where participants can win points and badges. One game asks people to count craters in photos of Mars; the other asks people to match small, high-res photos of the Martian surface with their corresponding locations on a low-res photo taken from a higher altitude [Seattle Post-Intelligencer]. (You’ll need to have Microsoft’s Silverlight application for the games and videos on the site to work.)

By enlisting citizen scientists, NASA hopes to both interest students in space careers and to make real progress in Martian research. “We really need the next generation of explorers,” says Michelle Viotti, from the agency’s Jet Propulsion Laboratory, which oversees Mars missions. “And we’re also accomplishing something important for Nasa. There’s so much data coming back from Mars. Having a wider crowd look at the data, classify it and help understand its meaning is very important” [BBC News].

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Image: JPL / Microsoft

Air travelers around the country saw their flights delayed this morning, thanks to a computer glitch. The problem, which occured [sic] in the Atlanta-based computer system that provides data about flight plans, has forced air controllers to input the information manually, said Arlene Salac, FAA spokeswoman in New York [Reuters].

The Federal Aviation Administration tried to assure travelers that the problem wasn’t a safety concern; rather it fouled up ground stops and caused delays. The problems began a little after 5 a.m. Eastern time, and hit Atlanta’s busy airport the hardest. One passenger said that a Delta Air Lines gate agent had announced that the glitch prevented pilots from accessing flight plans, the Atlanta Journal-Constitution reported [The New York Times].

The computer problem has been fixed, though FAA spokeswoman Kathleen Bergen said she doesn’t know how many flights have been affected [MSNBC]. And today’s glitch was the second such one in 15 months.

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Image: flickr/ eschipul

If  you read this blog last week, you might have seen us cover a study suggesting that South African sprinter Oscar Pistorius ought to be allowed to compete in the same track and field events as everyone else because his prosthetic legs confer no advantage over a sprinter with biological legs. But if you saw a study cited by the Associated Press and many other publications yesterday, you might think that Pistorius would soon be banned from competitions, because his “blades” let him swing his legs far faster than even the world’s fastest man, Usain Bolt. So what the heck is going on?

The AP’s study isn’t actually a “study,” per se. Rather, what the Journal of Applied Physiology published was a point-counterpoint (pdf), now freely available for anyone to read. In in, Peter Weyand and Matthew Bundle argue that Pistorius’ prosthetics are a huge advantage, particularly in what matters most: how fast he can move his legs. Weyand and Bundle say that the lightweight blades allow Pistorius “to reposition his limbs 15.7 percent more rapidly than five of the most recent former world-record holders in the 100-meter dash” [AP].

There is, however, a counterpoint to this argument in the journal piece that yesterday’s news reports neglected, coauthored by Alena Grabowski of the MIT Media Lab (who led the research on Pistorius’ blades that 80beats covered last week). Her team has found that the limiting factor determining an athlete’s top speed was how hard the foot or prosthesis hit the ground. Their study showed this “ground force” was around 9% lower in the prosthetic limb versus the unaffected leg [The Guardian]. Grabowski’s research focused on professional runners with only one prosthetic leg.

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Like humans, sea stars enjoy lounging on the shore during the hot summer months. But when they get too hot, they can’t run for shade, so they have a back-up plan—fattening themselves with cold ocean water before the tide recedes, according to new research published in the journal The American Naturalist. This finding shows that sea stars, or ochre starfish, aren’t as helpless as previously thought. The sea stars are likely cued during low tide that it’s a hot day, the researchers say, and that signals them to soak up more water during the next high tide. “It would be as if humans were able to look at a weather forecast, decide it was going to be hot tomorrow, and then in preparation suck up 15 or more pounds of water into our bodies,” said study researcher Brian Helmuth [LiveScience]. Talk about staying hydrated.

The researchers first studied starfish in an aquarium using heat lamps to simulate a scorching summer day, an infrared camera to measure their internal temperatures, and a scale to weigh the sea stars and determine how much water they had absorbed. The researchers say the amount of water a starfish absorbs can decrease its body temperature by almost 4 degrees Celsius. But researcher Sylvain Pincebourde is concerned that this novel strategy may have limitations in a rapidly changing world…. As oceans warm together with air temperature the thermoregulatory mechanism used by the starfish will cease to work, he warns. “The colder the sea water, the more it is able to lower its body temperature. The efficiency of this thermoregulation strategy therefore might be annihilated by ocean warming” [BBC News]. Yet another reason to get a handle on global carbon emissions.

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Image: flickr / laszio-photo

This week in Nature Geoscience, a cadre of scientists going by the name Global Carbon Project will publish a meta-analysis of global carbon emissions. The study led to headlines like, “Global CO2 emissions to drop 2.8 pct in ‘09: report,” and many others more in the ominous vein of “Earth ‘heading for 6C (6 degrees Celsius)’ of warming.” So how did both headlines come from the same study?

This year’s dip is correct: “In 2009, it is likely that the global financial crisis will cause global emissions to actually fall by a couple of percent,” said Michael Raupach, co-author of the report and co-chair of the Global Carbon Project [Reuters]. But, he says, the carbon cut will be short-lived if the recession ends.

In that case, the researchers say, the world will return to its normal trend. Since 2000 emissions have been rising by an average 3.4 per cent every year, compared to one per cent in the 1990s [The Telegraph]. Overall, worldwide emissions rose by 29 percent from 2000 to 2008, and the scientists put forward that 6 degrees Celsius global warming figure as a worst-case scenario—what could happen if the overall rising trend continued unabated.

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DeCode Genetics, a genome sequencing and drug development company, found out the hard way that predicting disease risk simply by reading someone’s genes isn’t so straightforward. On Tuesday, deCode filed for chapter 11 bankruptcy protection in Delaware. The company’s financial problems have also raised some troubling questions about genetic privacy.

DeCode’s mission was to uncover genetic risk factors for common diseases and to develop personal genome scans so individuals could learn their risk. DeCode quickly became the leader in the worldwide race to identify the causes of common disease. The company’s researchers discovered mutations linked to schizophrenia, heart disease, diabetes, prostate cancer and many other illnesses. Its approach was to identify the mutations first in Icelanders and then to confirm them in other populations [The New York Times]. Iceland was seen as an ideal spot for genetic studies, because the population was fairly isolated and the country has excellent medical and genealogical records. However, the company’s early successes did not translate into dollars, in part because the mutations they found only account for a small percentage of the overall incidence of a given disease.

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Toys, refrigerators, washing machines, socks—more and more products contain silver nanoparticles. It’s no wonder: These particles, which measure less 100 nanometers (smaller than a single HIV virus), can kill microbes on contact. But, researcher Darin Furgeson says, nanosilver can also escape into ecosystems and cause serious damage to fish embryos. Furgeson’s team published its results in the journal Small.

In one new experiment, Furgeson, a professor of pharmaceutical sciences, exposed zebrafish embryos to silver nanoparticles in a laboratory, and found that some died and others were left with dramatic mutations. “Some of the fish became extremely distorted, almost making a number nine or a comma instead of a linear fish,” he said [Scientific American]. Eyes, tails, and other body parts turned out malformed in the fish that survived.

Just how much nanosilver gets into the environment? A separate study from Environmental Science & Technology washed nine kinds of nanosilver-containing textiles, including some “anti-bacterial and anti-odor socks” that are already on the market. The researchers found that anywhere from less than 1 percent to as high as 45 percent of the silver came out in the first wash. Most of the silver was in the form of coarse particles of greater than 450 nanometers, suggesting that mechanical stress in the washing machine was responsible for most of the release [The New York Times], and that the nanoparticles might have aggregated to reach that size.

Those nanoparticles flushed out by a washing machine can end up in both fish habitats and drinking water supplies. Furgeson says his fish experiments could help show whether nanosilver is a health concern for humans, too. “Zebrafish have similar tissues and organs to us,” Furgeson said. “They don’t have lungs, but they do have a liver, kidneys and heart – though it is only two chambered – and they have a blood-brain barrier” [Scientific American].

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Image: Wiki Commons / Kristof vt

The elites of ancient Egypt had money, power, divine status in the case of the pharaohs, and also heart disease. In a study in today’s issue of The Journal of the American Medical Association, a team of researchers reports performing x-ray scans of 20 Egyptian mummies and finding them rife with cardiovascular disease like clogged arteries, one of the commonest ailments in modern American society.

On a visit to the Museum of Egyptian Antiquities in Cairo, one of the researchers had been intrigued by a nameplate on the remains of Pharaoh Merenptah, who died in 1,203BC. The plate said the pharaoh died at the age of 60 and suffered diseased arteries, arthritis and tooth decay [The Guardian]. So the scientists obtained permission to scan that mummy and others in the museum collection.

The common people of ancient Egypt weren’t mummified; only elites like royal families, their nursemaids, and priests got such a treatment. The elites ate salted fish, bread, and cheese like everyone else, but they also dined on rich foods such as cow, sheep, and goat meat, as well as honey and cakes with butter, says Abdel Nureldin, a professor of Egyptology at Cairo University, who worked on the investigation. At the same time, virtually no one in ancient times was sedentary, and that may have helped counteract their fatty diets [ScienceNOW Daily News].

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One single difference in the human genome may play a role in behaviors such as empathizing and responding to stress. The research, published in the journal Proceedings of the National Academy of Sciences, focused on a single gene, called OXTR, which carries the design and production blueprint for cells scattered throughout the heart, uterus, spinal cord and brain that serve as docking stations for a chemical called oxytocin [Los Angeles Times]. Oxytocin is a chemical produced in the brain that makes us feel all warm and fuzzy when we interact with others in a nurturing or bonding way; it has also been shown to help mice stay calm when under stress.

The researchers decided to investigate a region on the OXTR gene associated with decreased social interaction in humans to see if small changes correlated to a person’s sociability and ability to handle stress. They put 192 college students through experiments to measure empathy and stress. One in four of the subjects had a particular variation of that gene region, and those subjects were significantly better at accurately reading the emotions of others by observing their faces than were the remaining three-quarters of subjects [Los Angeles Times]. The people in this subset were also less likely to startle during the stress test, and reported that they were generally chill folks.

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