Tag: Science

A Spider That Likes Stinky Socks

  • Venue: Science Magazine


Arachnophobes everywhere will be heading to the laundromat when they hear this. Researchers have found that an East African spider, Evarcha culicivora, is attracted to your stinky socks. By presenting the spiders with a pair of socks worn continuously for 12 hours and a pair of identical unworn socks, researchers showed that the arachnids prefer the smell of human feet. Luckily for us, it’s likely that the spider’s odor detection has evolved not to find humans, but rather to catch the mosquitoes that carry our blood, researchers report online today in Biology Letters. Still, it might not be a bad idea to take your socks off before bed.

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Ancient ‘Seaweed’ Rewrites History

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The discovery of leaf-thin, seaweed-like fossils in China nudges back the moment when ancient life went from microscopic to merely tiny. At 600 million years old, the new fossils—called the Lantian Formation—are 27 million years older than the so-called Avalon fossils found in Canada and England, which, until now, were the earliest known fossil assemblage of multicellular life. The new specimens, some resembling modern day seaweeds, represent 15 or so photosynthetic algae researchers report online today in Nature. Unlike the Avalon fossil organisms, which thrived in deep-water environments, these ancient “seaweeds” lived in shallow marine seas. That means paleontologists need to rethink their theory that oxygenation of the deep oceans triggered the rise of more complex organisms.

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Marine Mud Is High in Fish Poop

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Will you still enjoy feeling the beach between your toes this summer knowing it’s partly fish feces? In a paper published online this week in the Proceedings of the National Academy of Sciences, researchers report that 14% of the calcium carbonate that makes up the muddy floors of shallow tropical seas is fish poop. Fecal samples from 11 common tropical fish, including barracudas and snappers, reveal that calcium carbonate forms a key component of the excrement. The team estimates that every year, tropical fish excrete 6.1 million kilograms of calcium carbonate, equivalent to the weight of 1000 adult elephants, over an area of 111,577 square kilometers. Each fish may even have its own unique “fecalprint”, with specific sizes and shapes of calcium carbonate crystals (as seen in the black and white image), which could allow future oceanographers to analyze an ocean’s mud to track changes in the numbers and diversity of fish species.

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Dinosaur Munchies May Have Bulked Up Pinecones

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The next time you step on a big, spiky pinecone, blame a dinosaur. A new study suggests that these seed carriers used to be soft and thin but that they had to toughen up when dinos with long necks started nibbling on them.

Conifers, such as today’s cypresses, Douglas firs, and giant redwoods, produce two types of cones: slender male cones that release pollen and bulky female cones that house the seeds. Ancient conifers also produced two cones, but palaeobotanist Andrew Leslie of Yale University noticed that they were both slim and unassuming, like today’s male cones.

Eager to find out what made the female cones bulk up, Leslie scoured the world’s herbariums—calipers in hand—in search of well-preserved fossil conifers. He compared the 70 or so specimens he found with more than 200 living species. Leslie’s early observation stood up: Female cones have gotten fatter. This widening was not a result of larger seeds but instead a broadening of the scales with which the cone arms itself against grazers, he reports online today in the Proceedings of the Royal Society B.

Leslie found the first cases of wider seed cones in the Jurassic period, a time when very large vertebrate herbivores, such as the long-necked sauropods Diplodocus and Barapasaurus, roamed Earth. These dinosaurs would have been able to graze much higher than earlier species, putting female cones at risk.

Scientists are still debating whether sauropods lifted their necks to feed from the tops of trees, as giraffes do. But even without reaching up, they could graze up to a height of 5 meters. “This still represents a notable increase in browsing height compared to previous vertebrate herbivores, which were mostly browsing around 1 meter or less,” Leslie says.

“It is quite a striking pattern now that someone has pointed it out,” says plant evolutionary biologist Peter Crane of Yale, who was not involved in the study. Still, one shouldn’t rush to blame sauropods, he says. “I don’t think we should forget early birds and mammals.”

Leslie agrees: “The fossil record is pretty useless for showing what was living up in the trees.” This makes it difficult to establish whether conifers were arming themselves against taller dinosaurs or against early mammals and birds that were also beginning to appear in the late Jurassic and early Cretaceous periods. Even insects could have played a role. “We also see an increase in the types of insect mouth parts,” Leslie says, so insects could have broadened their diets to include conifer cones.

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Organ Development in 3D

  • Venue: Science Magazine

organdev3dIf you ever wanted to know how the inner organs of a mouse embryo form, this is the movie for you. The animation was created by imaging thin sections of an embryo and then stacking these images to make a 3D movie. “If you look closely, you can see the developing lungs, gut, kidney, and bladder,” says the movie’s creator, Ian Smyth, a developmental biologist at Monash University in Australia. His video was selected from among several for being the most “striking and technically excellent” of the animations submitted to this year’s Wellcome Image Awards in London. Smyth uses these animations to compare normal tissues in embryos with those whose development is disrupted because of disease or exposure to a toxin. The animation was selected because of its ability to illustrate how effective this imaging technique can be for looking at the internal structure of the organs in a noninvasive way, explains Catherine Draycott, one of this year’s judges. “You can almost travel through [the mouse] as it develops.”

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Does Bird Flu + Swine Flu = Superflu?

  • Venue: Science Magazine

What do you get if you cross bird flu with the 2009 pandemic human virus, widely known as swine flu? Unfortunately, the answer isn’t funny. A new study predicts that swapping genes between the avian and human influenza viruses may result in an even more dangerous flu.

The human influenza virus H1N1 that caused the 2009 flu pandemic, and H9N2, an avian influenza virus that is endemic in bird populations in Asia, are close cousins—close enough that they can swap genes if they find themselves in the same cell, resulting in new viruses that are a patchwork of the parent strains. Scientists suspect that some gene combinations may result in a particularly potent form of flu and ignite a pandemic in humans. But because these viruses are more likely to meet in the lungs of an Asian chicken farmer than under the nose of a virologist, researchers find it difficult to predict which gene combinations might be the most virulent and contagious.

So instead of waiting and seeing, researchers have played matchmaker and thrust the two viruses together in a test tube. A team in China generated 127 hybrid viruses and injected each one into lab mice. More than half of the hybrids were as good as their parent strains at infecting the mice, and eight of them proved to be more pathogenic, the team led by Jinhua Liu of the China Agricultural University in Beijing reports online today in the Proceedings of the National Academy of Sciences.

“These are important experiments”, says virologist Peter Palese of Mount Sinai Medical Center in New York City, who was not involved in the work. The viral hybrids that the Chinese team has identified are the ones that scientists might want to watch out for worldwide, he says. If these strains were recognized early, governments could launch a speedier response.

Creating highly virulent viruses in the lab is controversial, says virologist Ab Osterhaus of the Erasmus University Medical Center in Rotterdam, the Netherlands. “[But] I don’t think we should shy away from these experiments. … The more information we have, the better,” he says.

He explains, however, that the hybrids that are the most virulent in mice will not necessarily be the most dangerous in humans, nor the most contagious. “Mice mirror, to a certain extent, what happens in humans,” he says, but they are not perfect model animals. Liu agrees. He plans to investigate how contagious his new viral blends are in guinea pigs and ferrets—animals whose respiratory system better reflects our own feverish battle with flu.

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May the Best Analyst Win

  • Venue: Science Magazine

LAST MAY, JURE ŽBONTAR, A 25-YEAR-OLD computer scientist at the University of Ljubljana in Slovenia, was among the 125 million people around the world paying close attention to the televised finale of the annual Eurovision Song Contest. Started in 1956 as a modest battle between bands or singers representing European nations, the contest has become an often-bizarre affair in which some acts seem deliberately bad—France’s 2008 entry involved a chorus of women wearing fake beards and a lead singer altering his vocals by sucking helium—and the outcome, determined by a tally of points awarded by each country following telephone voting, has become increasingly politicized.

Žbontar and his friends gather annually and bet on which of the acts will win. But this year he had an edge because he had spent hours analyzing the competition’s past voting patterns. That’s because he was among the 22 entries in, and the eventual winner of, an online competition to predict the song contest’s results.

The competition was run by Kaggle, a small Australian start-up company that seeks to exploit the concept of “crowdsourcing” in a novel way. Kaggle’s core idea is to facilitate the analysis of data, whether it belongs to a scientist, a company, or an organization, by allowing outsiders to model it. To do that, the company organizes competitions in which anyone with a passion for data analysis can battle it out. The contests offered so far have ranged widely, encompassing everything from ranking international chess players to evaluating whether a person will respond to HIV treatments to forecasting if a researcher’s grant application will be approved. Despite often modest prizes—Žbontar won just $1000—the competitions have so far attracted more than 3000 statisticians, computer scientists, econometrists, mathematicians, and physicists from approximately 200 universities in 100 countries, Kaggle founder Anthony Goldbloom boasts.

And the wisdom of the crowds can sometimes outsmart those offering up their data. In the HIV contest, entrants significantly improved on the efforts of the research team that posed the challenge. Citing Žbontar’s success as another example, Goldbloom argues that Kaggle can help bring fresh ideas to data analysis. “This is the beauty of competitions. He won not because he is perhaps the best statistician out there but because his model was the best for that particular problem. … It was a true meritocracy,” he says.

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Coral Time Sex to the Moon

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The romance of a full moon sometimes gets the better of Acropora palmata. The 2-millimeter-tall polyp, which forms vast coral reefs in the Caribbean Sea, holes up in its marine fortress and waits for the moon to shift from its usual blue hue to a redder glow. Then it waits a bit more. If this red glow is followed by several days during which no moonlight is visible—an event that occurs only in the days following a full moon—these marine creatures know it’s time for some serious synchronized sex. They release millions of eggs and sperm within a period of 20 minutes, ensuring that some young will survive parrotfish and other predators, researchers report this week in The Journal of Experimental Biology. That may explain why pilots often see red, 10-kilometer-long slicks of coral gametes a couple of days after a full moon.

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Why Some Penguins Wear a Blue Tuxedo

  • Venue: Science Magazine

Feeling small and blue today? Eudyptula minor goes through its whole life that way. This Australian bird—the smallest of all penguins at around 30 cm high—sports a notable blue tint in its feathers, hence its common name, the Little Blue Penguin. Using high-powered microscopes, researchers have now discovered that nanometer-sized fibers in the bird’s wing feathers provide the unusual blue hue. Made from keratin, the same material as human hair, these nanofibers are packed together like bundles of uncooked spaghetti, the team reports online today in Biology Letters. The penguin’s color is due to blue light that is scattered when it hits the fibers, while all other wavelengths of light just pass through the feathers. This is a new mechanism for giving feathers a blue color, the authors say; similar nanofibers are found in the blue skin of other birds, such as Emus, but those fibers are made of collagen. What advantage the colorful feathers provide for Little Blue remains unknown, but they certainly aren’t being caught dead in the same black and white tuxedo as most of their relatives.

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