Blogs / 80beats

In a match-up between an annoyed human brandishing a fly swatter and a buzzing fly, who wins? As most people know from frustrating experience, all too often the fly easily evades the human’s swat, and buzzes merrily into another region of the room. Now, using a high-speed camera, scientists have determined just how the fly makes its astoundingly effective escape.

Biologist Michael Dickinson used a video camera that shoots 5400 frames per second to record a fly’s precise motions when threatened with a swatting. The video showed that as a threatening object moved towards the fly from one direction, it shuffled its feat and positioned itself to take off in the opposite direction–all within 200 millisecionds. “They perform an elegant little ballet with their legs,” says Dickinson. “They move their legs around to reposition their bodies so that when they do jump, they will push themselves away from the looming threat” [NPR].

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When a hummingbird or a hawk moth sups on the sweet nectar of a wild tobacco plant, they’re not just getting a tasty meal in exchange for their services in spreading the plant’s pollen. Instead, a new study shows that the nectar may be a complex chemical cocktail that simultaneously attracts and repels pollinators in order to optimize the amount of time they spend at each flower, and the attention they pay to flowers on different plants. “This paper shows just how sophisticated a plant can be in using chemistry to get what it wants,” [The Scientist] says lead researcher Ian Baldwin.

The researchers had already analyzed the chemical composition of tobacco plants’ nectar; they found that the compound benzyl acetone is the primary attractant, and that the plants “spike” their nectar with nicotine, presumably as a poisonous deterrent to insects. But in a clever experiment, the research team created genetically modified plants with different levels of these two chemicals. In greenhouse and field experiments, the scientists were surprised to find that not only did nicotine deter nectar robbers and plant nibblers, but the right dose prevented pollinators from lingering too long at any one flower, increasing the number of flowers visited [Science News].

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Just as summer is giving way to autumn in the Earth’s northern hemisphere, the seasons are changing on Mars, too. Near the Martian north pole, the Mars Phoenix Lander is watching its environment grow darker and colder, bringing Phoenix a little closer the end of its mission each day. Meanwhile, in Mars’ southern hemisphere, the rovers Spirit and Opportunity have been reinvigorated with increased sunlight to power their solar panels, and are on the move once more.

Phoenix, which has conducted fascinating experiments on the planet’s soil and water ice, saw the sun dip below the horizon yesterday for the first time since it landed on May 25. NASA officials originally planned a 90-day mission for Phoenix, which would have ended operations this week, but since the lander is in excellent condition NASA extended its mission. “It’s doing fabulously,” said Barry Goldstein, NASA’s Phoenix project manager at the Jet Propulsion Laboratory in Pasadena, Calif. “But I’ve made it clear to the science team that the warranty’s over…. The vehicle is not going to tip over and die,” Goldstein said. “But we’re getting to the point where we’re going to start seeing the creaks and groans” [SPACE.com].

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Anthropologists have uncovered the remnants of a sophisticated network of settlements in the Amazon rainforest that date back to pre-Columbian days, and which challenge notions of what a complex and organized society can look like. The 28 towns and villages found thus far were tucked away in the forest and linked by roads, and may have supported as many as 50,000 people across an area slightly smaller than New Jersey. Says lead researcher Mike Heckenberger: “These are not cities, but this is urbanism, built around towns…. If we look at your average medieval town or your average Greek polis, most are about the scale of those we find in this part of the Amazon” [Reuters].

Researchers believe that these settlements were first occupied about 1,500 years ago, and say that indicates that the rainforest has been shaped by human habitation much more profoundly than previously realized. [T]he Western Amazon forest is not, strictly speaking, what could be called “virgin” forest. It is what took over after local cultures were wiped out by European settlers and their diseases and their towns and villages were left untended [New Scientist].

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Cane toads, the green and warty invasive animals that are spreading ruin throughout ecosystems in northern Australia, may not continue their relentless march southward towards the sea. According to a new study, lower temperatures in the south may stop the toads in their tracks.

Researchers coaxed the toads into hopping through a 2-meter course in a laboratory to make a so-called “cane toad Olympics,” and measured the cold-blooded creatures’ hops at different temperatures. They found that in temperatures above 80 degrees Fahrenheit, the toads could hop at a speed of over one mile per hour. But below 60 degrees Fahrenheit, they slowed to a glacial .2 miles per hour. “This means that there’s no way the toads could invade southern parts like Melbourne, Adelaide … because they wouldn’t be able to move,” said researcher Dr Michael Kearney…. The winters of southern Australia would be too cold for the cane toads to forage or spawn, he said [The Age].

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Minuscule viruses on the sea floor have a big impact on the marine ecosystem, a new study shows. The viruses infect simple microbes, known as prokaryotes, that form one of the lowest rungs in the food chain. Usually the nutrients and carbon contained in prokaryotes are used by the larger organisms that eat them, but something very different happens when prokaryotes are infected by viruses: the viruses burst the prokaryotes open and release their carbon and nutrients into the water column [New Scientist]. When these nutrients sink down to the ocean floor they’re consumed by other microbes, which then multiply and provide more hosts for the viruses.

Researchers long ago grasped that viruses on the sea surface play a Dr.-Jekyll-and-Mr.-Hyde role, killing biomass while at the same time sustaining it. Now, though, evidence has emerged that these tiny bacterial pathogens also carry out unsung work at the ocean depths — a dark, inhospitable, nutrient-poor place that counts as last great unexplored ecosystem on the planet [AFP]. Researchers say the newly discovered role of deep sea viruses may also play a critical role in the carbon cycle, as the decaying remnants of the burst microbes carry carbon, which is sequestered in the ocean depths.

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Scientists have produced the cells that make up delicate inner ear hairs in mouse embryos, a step that could point the way to reversing hearing loss and curing congenital deafness. Sensory hair cells inside the cochlea, the auditory portion of the inner ear, convert sound waves into electrical impulses that are delivered to the brain. The loss of these minute hairs, or the nerves that control them, is the most common cause of hearing impairment and so-called nerve deafness [ABC Science].

Researchers used gene therapy to create the crucial cells: They used a virus to introduce a gene into the mice embryos, which caused non-sensory cells to turn into cochlear hair cells. While this preliminary experiment was done on normal-hearing mice, the discovery that the engineered cochlear cells functioned as well as natural cells was an important step. Says lead researcher John Brigande: “One approach to restore auditory function is to replace defective cells with healthy new cells…. Our work shows that it is possible to produce functional auditory hair cells in the mammalian cochlea” [Reuters].

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It may not be a big market, but it’s presumably a lucrative one: To meet the needs of consumers who are in the business of transmitting classified national secrets, physicists are working on an absolutely secure communication system that uses the strange laws of quantum mechanics to encode information. The latest experiments in this field, called quantum cryptography, produced a system that researchers say would theoretically work to transmit information around the globe.

The system relies on a concept known as quantum entanglement to establish hack-proof communication. Entanglement allows two particles to be quantum-mechanically connected even when they are physically separated. Although the specific condition of either particle cannot be precisely known, taking measurements of one will instantly tell you something about the other. The trick can’t be used to actually send information, because each particle’s condition is random until it is measured. But entanglement can be used for encrypting data if a sender and a receiver make measurements on a number of entangled particles and then compare their results [Nature News].

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The cosmic collision of two galaxy clusters has given astronomers a clearer look at the mysterious substance known as dark matter. Researchers say when the two clusters crashed into each other, the dark matter from each cluster [appeared] to pass through the cosmic mess unscathed, leaving ordinary matter behind in the galactic pileup [SPACE.com]. Using data from NASA’s Hubble and Chandra space telescopes, astronomers were able to produce an image showing clouds of dark matter, colored blue, on either side of the impact site.

Dark matter, mysterious stuff that exerts a gravitational force on other matter, was originally proposed to explain what holds spinning galaxies, like the Milky Way, together. Observations suggest it outweighs ordinary matter by a factor of about 6 to 1. But no one knows what it is made of, and normally dark matter and ordinary matter are too well mixed to observe the dark matter independently [New Scientist].

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In a discovery that’s being hailed as a leap forward in regenerative medicine, researchers have found a way to transform common pancreatic cells in an adult mouse into the rare, insulin-producing beta cells that are destroyed in type 1 diabetes. Previously, researchers believed that the only way to transmute an adult cell was to first coax it back into stem cell form and then to reprogram it; this new research removes the first step entirely.

The accomplishment raises the tantalizing prospect that patients suffering from not only diabetes but also heart disease, strokes and many other ailments could eventually have some of their cells reprogrammed to cure their afflictions without the need for drugs, transplants or other therapies. “It’s kind of an extreme makeover of a cell,” said [lead researcher] Douglas A. Melton…. “The goal is to create cells that are missing or defective in people. It’s very exciting” [Washington Post].

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It’s a demonstration of unconscious brain power: A new neuroscience study shows that people can make decisions based on input that is invisible to the conscious mind. Researchers say the findings aren’t evidence of the efficacy of subliminal messages, which have mostly been discredited. But there has been a more subtle phenomenon, billed as the foundation of intuition, where seasoned poker players may play more successfully because they can pick up subtle signals in the body language of their opponents - without consciously realising it - to work out if they are bluffing [Telegraph].

In the study, published in the journal Neuron [subscription required], test subjects were repeatedly shown brief abstract animations before being asked whether they wanted to take a gamble, which could either earn or lose them a small amount of money. The animations had hidden symbols that indicated whether the subject would win or lose on the subsequent bet; over time, test subjects got better at predicting whether they would win or not.

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A pesky computer virus that has popped up on computers around the world has now made the leap into space. NASA announced yesterday that several laptops on board the International Space Station were infected with the virus in July, and also admitted that such infections have happened before.

“This is not the first time we have had a worm or a virus,” NASA spokesman Kelly Humphries said. “It’s not a frequent occurrence, but this isn’t the first time.” … NASA downplayed the news, calling the virus mainly a “nuisance” that was on non-critical space station laptops used for things like e-mail and nutritional experiments [Wired News].

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A man who was paralyzed below the waist 20 years ago is walking again, thanks to a robotic “exoskeleton” that moves his legs and can even navigate up and down hills. The inventors of the device, dubbed the ReWalk, say the experimental technology can give paraplegics a psychological boost through renewed mobility, and can also help people avoid medical problems caused by long-term wheelchair use.

One of the first paraplegics to test out the device is Radi Kaiof, a former Israeli paratrooper who has been paralysed for the last 20 years following an injury during his service in the Israeli military. He says the device has changed his life. “I never dreamed I would walk again. After I was wounded, I forgot what it’s like. Only when standing up can I feel how tall I really am and speak to people eye to eye, not from below” [BBC News].

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Yesterday, NASA released the first set of images from its newest space telescope, the Gamma-Ray Large Area Space Telescope, which has now been renamed Fermi in honor of the particle physicist Enrico Fermi. After less than three months of collecting data, the Fermi telescope produced a map of the sky showing the sources of powerful gamma rays as bright spots of light.

“I like to call it our extreme machine,” said Jon Morse, the director of astrophysics for NASA. “It will help us crack the mysteries of these enormously powerful emissions.” Gamma rays are powerful light rays invisible to the naked eye [Washington Post]. As the Earth’s atmosphere absorbs gamma rays, they can only be studied from an orbiting telescope.

The $700 million telescope will observe gamma rays emitted by black holes, neutron stars, and other cosmic eccentrics, and will also scan the skies for the mysterious gamma ray bursts that are of special interest to astronomers because they are among the brightest events ever observed. The intense flashes of gamma rays can release within seconds the same amount of energy that the sun will put out over its entire ten-billion-year lifetime—but no one is sure what causes them. The going theory is that the bursts are tied to the explosive deaths of massive stars, but exactly what types of stars and how the explosions are triggered remains a mystery [National Geographic News]. Already, the Fermi telescope has detected gamma ray bursts at a rate of about one a day.

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Archaeologists have recreated the stone tools made by Neanderthals, and found them to be as useful and efficient as those made by the earliest Homo sapiens, who survived while the Neanderthal line died off. The new research is one of many recent studies claiming that Neanderthals weren’t just dumb brutes that were out-competed by early humans. Says lead researcher Metin Eren: “When we think of Neanderthals we need to stop thinking in terms of ’stupid’ or ‘less advanced’ and more in terms of ‘different’” [Guardian].

Other recent studies have argued that Neanderthals hunted and communicated as well as the early Homo sapiens who arrived in Europe, where the Neanderthals already lived, about 45,000 years ago. But some archaeologists still believed that Homo sapiens had a technological advantage, because they used long stone tools called blades, as opposed to the Neanderthals’ disk-shaped flakes. In the new study, Eren’s team spent spent three years recreating blades and flakes, then measured their cutting power, durability and the amount of effort needed to produce them [Wired News]. In the end, Eren determined that the Neanderthals’ tools may have even had a slight edge over Homo sapiens tools.

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