Recently in Biological physics Category

Science: A mere 475 right whales summer in the western North Atlantic Ocean, and they have much lower reproduction rates than right whales that summer near Antarctica. One reason for that may be noise-induced stress. Rosalind Rolland of the New England Aquarium in Boston and colleagues report in the Proceedings of the Royal Society B that reduced ship traffic in the Bay of Fundy in the aftermath of the September 11, 2001, terrorist attacks resulted in a 6-decibel decrease in underwater noise, specifically low-frequency noise. Baleen whales, including right whales, use low-frequency sounds to communicate, and prior studies have shown that they change their behavior and vocalizations when noise increases. Rolland found that the Bay of Fundy's period of quiet was associated with a significant reduction in stress-related fecal hormone metabolites excreted by the whales.

Daily Mail: Neuroscientists at the University of California, Berkeley, have been developing a computer program that can decode brain activity and put it into words, writes Tamara Cohen for the Daily Mail. To monitor information from the temporal lobe, where sounds are processed, the scientists inserted electrodes into the brains of 15 patients whose skulls had been cut open for an epilepsy treatment. As the patients listened to a person speaking, the computer analyzed how the brain processed the words they heard. It was able to translate the spoken words into patterns of electrical activity and then translate them back into the original sounds, or something very similar. Brian Pasley, coauthor of a paper published in PLoS Biology, said that with more work, brain recordings could allow scientists to "synthesize the actual sound a person is thinking." Such technology could benefit people whose speech has been affected by stroke or degenerative disease.

BBC: Researchers at the Stanford University School of Medicine have succeeded in converting mouse skin cells into "neural precursor" cells, which can develop into three types of brain cell. The group's findings, published in the Proceedings of the National Academy of Sciences, may be important for certain medical therapies, such as bone marrow transplants. Until now such transplants have relied on stem cells, which can divide and differentiate into many different specialized cell types. Stem-cell research has been hampered by ethical concerns, however, because one source of the cells has been human embryos. More work will have to be done to re-create the experiment using human skin cells.

BBC: Researchers at Duke University have been working to develop synthetic nanoparticles that can boost the human body's immune system. They have engineered tiny capsules that mimic mast cells—which respond to fight infections near the skin—by releasing a body chemical called tumor necrosis factor, which battles certain types of bacteria and viruses. The nanoparticles, when injected into mice simultaneously with a vaccine, have been shown to improve the infected animals’ survival rate. Soman Abraham and colleagues said different immune system chemicals could be added to the nanoparticles, depending on which vaccine will be used.

BBC: Global climate shifts and flu pandemics may be linked, say researchers. Weather can influence the migratory patterns of wild birds; thus different species are brought together that don’t normally mix. The birds then share viruses, which can morph into different strains to which the human population has not been previously exposed. In a paper published yesterday in the Proceedings of the National Academy of Sciences, Jeffrey Shaman of Columbia University and Marc Lipsitch of Harvard University note that the four most recent human influenza pandemics—in 1918, 1957, 1968, and 2009—were preceded by a climate pattern called La Niña. However, the researchers emphasize, most La Niñas have not preceded a pandemic. Rather, climate patterns could be one of several factors that affect the spread of viruses.

BBC: Rhinos are one of the biggest living land mammals, yet little is known about the physics and mechanics of their relatively small feet. Unlike elephants, which have five forward-pointing toes and one "false toe" that points toward the heel, rhinos have three rigid toes and a more evenly spread pad across the sole of the foot. John Hutchinson of the Royal Veterinary College and colleagues are working with rhinos who have been trained to walk on a high-tech track that measures the amount of force the rhinos put on individual regions of their feet. Thus far, Hutchinson and his team have found that rhinos generate the highest pressures on the inside part of the foot—again in contrast with elephants, which generate the highest pressures on the outside. The study should help with the development of more targeted approaches to alleviate the foot problems that plague captive rhinos.

Discover: Researchers have genetically modified silkworms to produce a hybrid silk that’s partly from silkworm and partly from spider. Spider silk is extraordinarily strong and tough and can stretch several times its original length. Farming spiders has not proven as practical as farming silkworms, however, because spiders are territorial and cannibalistic. So Donald Jarvis and Randy Lewis of the University of Wyoming and Malcolm Fraser of the University of Notre Dame inserted spider silk genes into the silk-making glands of silkworms. Although the new silk is only 2–5% spider silk, it is stronger, more elastic, and twice as tough as normal silkworm fiber. Spider silk could have many uses, such as in sutures, artificial ligaments, and body armor.

Nature: Anomalocaris was a shark-sized, soft-bodied predator that inhabited the oceans in the Cambrian period. Possessing two front claw-like limbs, it looked like a shrimp, but with fins instead of legs. New fossil evidence has revealed another resemblance to shrimps and other arthropods: Anomalocaris had compound eyes. What's more, each of the two eyes of Anomalocaris contained at least 16 000 individual hexagonal lenses. Although modern dragonflies have 28 000 lenses per eye, ants and files have far fewer and likely cannot see as clearly as Anomalocaris could. The lens-containing fossils were discovered in a shale formation in Emu Bay, South Australia, by John Paterson of the University of New England in Australia and his colleagues. Until the team's discovery, compound eyes had been observed only in creatures that have exoskeletons, which suggested—wrongly it now seems—that compound eyes evolved alongside exoskeletons.

Daily Mail: Philips, a Dutch electronics company, is developing a bio-light that provides illumination using the same method as fireflies and glow worms, writes Gareth Finighan for the Daily Mail. The lamp consists of a series of glass chambers that contain bioluminescent bacteria, which glow green when fed methane gas pumped into the unit through a household-waste digester. Although most people would not necessarily want to introduce bacterial cultures into their homes, such a lighting method could have outside applications, such as illuminating walkways. The company is also working on an alternative method that uses fluorescent proteins that emit different frequencies of light. “Energy-saving light bulbs will only take us so far. We need to push ourselves to rethink domestic appliances entirely, to rethink how homes consume energy, and how entire communities can pool resources,” said Clive van Heerden of Philips Design.

BBC: A group of researchers at the University of Washington in Seattle is developing a contact lens that can project images in front of the eye through the use of an embedded pixel array. Such a device has been challenging to create because it not only requires a suitable power source and mechanical and electrical integration of its micrometer-scale components but it also must be biocompatible. In addition, the human eye usually can focus only on objects at least a few centimeters away, whereas a contact lens rests on the eye’s surface. Nevertheless, the researchers have built a single-pixel prototype device, which they have successfully tested on rabbits. In humans, such lenses could have many uses, such as to relay information from navigation systems, enhance video gaming, or alert the wearer to physiological problems like abnormal glucose levels, write Babak Parviz and colleagues in the Journal of Micromechanics and Microengineering.

Science: Graduate students who study biological physics now have their own international network to help them advance their careers. The Physics of Living Systems Student Research Network (PoLS-SRN) is hosted by the center for theoretical biophysics at the University of California, San Diego, and includes 28 participating institutions from North and South America, Europe, and Asia. Biological physics is a relatively young, interdisciplinary field that lacks the career networks that form naturally when several "generations" of researchers spread out and establish laboratories. One goal of PoLS-SRN is to introduce theorists and experimenters who work on the same problems.

Science: The International Classification of Diseases has served for more than 100 years as a standard for the World Health Organization, physicians, and the healthcare industry to track disease incidence, make diagnoses, and determine reimbursement for care. Last year, however, the National Institutes of Health decided it was time to update it. What the resulting National Research Council panel has proposed is a massive data network that would combine cutting-edge genomic and molecular data on patients' diseases with their routine medical records, writes Jocelyn Kaiser for Science. That system would be used to develop a new disease taxonomy and personalize medical care, according to the 108-page report, titled Toward Precision Medicine: Building a Knowledge Network for Biomedical Research and a New Taxonomy of Disease. Creating such a network of data is expected to take a decade or two, and it will require a change in the public’s attitude toward patient privacy and the use of personal medical data for research.

BBC: New radio carbon dating and DNA tests of a mastodon rib with a bone spear point embedded in it show that the spear point was itself fashioned from mastodon bone—13 800 years ago, some 800 years before the arrival of the Clovis hunters who were once thought to be the first inhabitants of North America. Michael Waters of Texas A&M University and colleagues used accelerator-based mass spectrometry to date specific amino acids they extracted from the collagen in the bone. Computed tomography, which creates 3D x-ray images of objects, showed how the spear point had been sharpened to a needle-like point. The fact that humans in North America had effective hunting technologies well before the Clovis people suggests that Ice Age fauna may have had to contend with greater hunting pressures, much earlier, than previously thought.

BBC: A team of researchers at the Joseph Fourier University in Grenoble, France, is working on a biofuel cell that uses glucose and oxygen at concentrations found in the human body to generate electricity. Serge Cosnier and colleagues estimate that within a decade or two, biofuel cells may be used to power a range of medical implants, from sensors and drug delivery devices to entire artificial organs, writes David Cohen for the BBC. The fundamental limitation on such devices has always been the battery needed to keep them running; whereas batteries need to be continuously replaced over a patient’s lifetime, biofuel cells could keep working indefinitely. A biofuel cell is made of two special electrodes. One removes electrons from glucose, and the other donates electrons to oxygen and hydrogen molecules, producing water. Although biofuel cells were first proposed in the 1970s, recent breakthroughs in the understanding of enzymes have resulted in several groups around the world working on such devices.

Nature: An international team of researchers has developed a brain implant that enables monkeys to examine virtual objects by means of a virtual arm controlled by their brain, writes Susan Young for Nature. Miguel Nicolelis of Duke University and coworkers inserted electrodes into the motor cortex and somatosensory cortex brain regions of two monkeys. The monkeys were trained to use only their brain to explore virtual objects on a computer screen by moving a computer cursor or a virtual image of an arm. The electrodes in the motor cortex recorded the monkeys’ intentions to move and relayed that information to the virtual world. As the virtual hand passed over objects on the screen, electrical signals were fed into the animal’s somatosensory cortex, which provided “tactile” feedback. The researchers hope that their technique could eventually help patients who are severely paralyzed to achieve full-body mobility through the use of robotic prosthetics.

Nature: Icelandic singer Björk's album Biophilia, which is released in two weeks, features songs about DNA, crystals, viruses, and electricity—each accompanied by an iPad app. Björk tells Nature's Andrew Mitchinson that the lessons are designed for children: "I felt that the years between five and eight, when a child's brain is soaking up languages and learning to read and write, are the perfect time to absorb musical theory." As part of her musical science tour, she'll be holding workshops at science museums around the globe, including in San Francisco.

BBC: Environmental engineers at the Pennsylvania State University are developing a process that involves a microbial fuel cell to treat wastewater and produce hydrogen gas without consuming electrical grid energy. In this method, bacteria break down wastewater by eating the organic material and releasing electrons as a byproduct. Bruce Logan and his coworkers' prototype attempts to collect those electrons, along with the hydrogen gas produced, in the fuel cell. The electrons are directed through a circuit that can power a small device, such as a fan or a light bulb. Additional hydrogen can be produced from the wastewater by applying extra voltage to the system, which leads to the electrons produced by the bacteria to bond with protons found in the water.

To avoid the need for external power, the team members are experimenting with a process called reverse electrodialysis, which generates electricity from the salinity difference between seawater and fresh water. "You're actually creating energy and desalinating the water and treating the wastewater. It's a triple play," Logan was quoted as saying in an NSF press release. Logan hopes that within the next 5–10 years microbial fuel cells will generate enough electricity to power a wastewater treatment plant with energy left over to share with the nearby community.

Science: The terrorizing wail of the Stuka dive bomber came from wing-mounted sirens called Jericho Trumpets. The male Anna's hummingbird (Calypte anna) also makes a characteristic noise when it dives, but the squeaky sound is meant to woo, not frighten, females. Three years ago Christopher Clark discovered that the hummingbird's diving sound originates in its tail feathers. Now, as Science's Daniel Strain reports, Clark has identified the underlying mechanism. By putting tail feathers in a wind tunnel, Clark, who is now at Yale University, and his colleagues found that the feathers begin to flutter with sound-generating rhythm when the wind speed matches the bird's diving speed of 7–20 m/s. Clark's paper describing his research also appears in Science.

Nature: Pili, which are hairlike filaments that sprout from some bacteria, can enable the bacteria to remove uranium from contaminated groundwater without becoming poisoned in the process. Geobacter sulfurreducens, for example, obtains energy by reducing, or adding electrons to, metals in the environment; when pili are present, the bacterium is able to do this outside the cell envelope. In addition to keeping uranium out of the bacterium itself, pili provide a greater surface area for electron transfer, increasing the amount of uranium removed. Gemma Reguera of Michigan State University, who participated in the discovery, is most excited about the possibility of developing nonliving nanowires that share the pili's properties of electron transfer. Such devices could be used in environments where bacteria can't live, such as the Fukushima Daiichi plant in Japan. It's possible that conductive nanowires could also be used to remove radioactive isotopes of plutonium or cobalt.

BBC: According to vast computer simulations of debris thrown up from asteroid impacts on Earth, more life-bearing particles could have been scattered to Mars, Jupiter, or even beyond our solar system than previously thought. Mauricio Reyes-Ruiz of the National Autonomous University of Mexico and his colleagues have carried out the largest-ever simulations of the process, which considered impacts of varying intensity. Because of new and better computing systems, the researchers were able to study the effects over much longer time periods, up to millions of years. The most important question, however, is whether any ejecta could carry living cargo. The researchers think so, as such small, hardy organisms as water bears have already demonstrated their ability to survive the harsh conditions of space. Preliminary results were presented at January’s American Astronomical Society meeting.

Earth magazine: Over the past decade, a team from the US Geological Survey has been studying the long-term health risks for rescue workers, civilians, and survivors directly affected by the 9/11 terrorist attacks. The US Environmental Protection Agency and the Public Health Service Commissioned Corps called in the USGS because of its expertise in categorizing dust and airborne contaminants, especially using remote sensing. Since 2001 the USGS has been increasingly involved in disaster response; it sent out teams in 2005 following Hurricane Katrina and in 2007 and 2009 during the California wildfires. Meg Marquardt, writing for the American Geological Institute’s Earth magazine, discusses the USGS’s methods and what they have found.

BBC: Woody plants probably appeared earlier than previously thought. Phillipe Gerrienne of the University of Liege, Belgium, and colleagues made a study of plants from the Early Devonian age, about 10 million years before the widespread appearance of shrubs and trees, and found rings of cells that are characteristic of wood. Rather than to provide structural support, that woody substance may have been used to enhance the flow of water in plants. While some early ferns produced some wood, they didn't show the characteristic pattern of cell division perpendicular to the stem typical of lignophytes. The plants in the study, which were herbaceous and probably no more than 20–40 cm tall, would not necessarily have been distinguishable externally from nonwoody plants.

Science: To better manage the world’s coral reefs—many of which are suffering because of overfishing of algae-eating fish, pollution, and temperature spikes—ecologists have performed a global assessment of the most susceptible ones. They believe that by focusing on the reefs that have the best chance of surviving, and ignoring the ones that are likely to die anyway, reef managers can be more effective. Ways to help restore coral reefs include restricting fishing and reducing pollutants in the water that then runs off land near reefs. More than 100 million people depend on coral reefs for food and many more rely on reefs as buffers against high waves. Yesterday the team published its findings in PLoS ONE.

BBC: Benjamin Blankertz and his colleagues at the Berlin Institute for Technology have demonstrated in the lab that it's possible to detect a driver's intention to brake before he or she actually brakes. In their experiment, volunteers drove an arcade-like simulator and were given the task of keeping a fixed distance away from the car in front. A helmet studded with electrodes monitored their brain waves. Whenever the car in front braked, the helmet picked up a telltale signal that heralded the driver's application of the brake pedal 130 milliseconds later. At 113 kilometers (70 miles) per hour, a delay of 130 ms corresponds to a length of 4 meters. If the helmet could be replaced with a more comfortable, less obtrusive device, brain-wave detection could provide a means to shorten stopping distances and avoid accidents, the researchers say.

MSNBC: Zvonimir Dogic of Brandeis University and his colleagues have performed an experiment that helps solve a biological mystery: how cilia, the microscopic hairs that sprout from certain cells, beat together to perform such useful tasks as expelling mucous from lungs and ferrying eggs from ovaries into the uterus. Dogic's team made artificial cilia from just three components: microtubule filaments, motor proteins called kinesin, and a bundling agent. Although the artificial cilia lacked a dedicated internal means to communicate with each other, the researchers found that the cilia spontaneously beat together under certain external conditions. The simplicity of the artificial system could lead to nonbiological applications.

Science: Like little batteries, bacteria have two charges: positive on the outside of their cell membranes, negative on the inside, writes Sara Reardon for Science. And as with batteries, that division of charge is their power source. By pumping protons across their membrane, bacteria can make energy, spin their flagella so they can swim, and drive the pumps that bring in food. Researchers have now found that Escherichia coli drop the voltage difference for a brief moment and depolarize, much as neurons do when they fire. The phenomenon could help explain how some bacteria resist antibiotics: By depolarizing their membranes, the bacteria may be able to kick out charged molecules, such as toxins, that they’ve accumulated.

BBC: Researchers at the University of Bath and the University of the West of England are growing seven algae species in the UK's Roman Baths in Bath to find the best one for biodiesel production. Although studies to create biodiesel from algae have been carried out for the past 20 years, limitations currently prevent its use on a large scale. Because much of the world's arable land is being used for food production, an algae species that can grow in areas that don't already have other uses, such as the desert, is being sought. Also, algae cell walls are difficult to break, so extracting the oil inside is an energy-intensive process. As a result, researchers are also looking for a species with a weaker cell wall and a higher oil content. "The results of this study will help us identify whether there is a particular algae species among the seven identified in the Roman Baths that is well adapted to growing at higher temperatures and also suitable for producing sufficient amounts of biodiesel to make wide-scale production viable," said Rod Scott, one of the research team's members.

Nature: Genetic diseases such as hemophilia may one day be treated through a gene-editing process. Katherine High, a hemophilia researcher at the Children's Hospital of Philadelphia, teamed up with researchers at Sangamo BioSciences in Richmond, California, who are experts on enzymes called zinc-finger nucleases (ZFNs). They treated hemophilia in mice that were engineered to carry the faulty human gene; the researchers used ZFNs as molecular scissors to cleave the genome at the F9 gene—where people with hemophilia B have multiple mutations—and insert a healthy gene. After treatment, the animals' blood clotted in 44 seconds, compared with more than a minute for mice with hemophilia. "In theory, almost all genetic diseases could be amenable to this type of treatment," said Mark Kay, a gene-therapy researcher at Stanford University. Much more work must be done, however; many questions remain about how to get the right amount of DNA to the right cells and how to guarantee the ZFNs cut the right bit of DNA. High and colleagues' work was published yesterday in Nature.

BBC: Adult birds will often flap their wings and run up steep inclines rather than fly over them. Brandon Jackson of the University of Montana wanted to know why birds capable of flight use the flap-run motion, writes Victoria Gill for the BBC. To measure birds' muscle activity, Jackson and his colleagues implanted electrodes into the flight muscles of pigeons. They found that, for birds, running up a ramp with a 65-degree incline requires about 10% as much power from the flight muscles as flying. Flap-running is also a crucial step in learning to fly—young birds that can't fly yet due to small or weak wings use it to get off the ground and away from predators, transitioning gradually to full flight as they mature. Jackson deduced that dinosaurs with similarly small, weak wings could have also flap-run and transitioned toward flight over evolutionary time.

New Scientist: A research group at the University of Minnesota in St. Paul caused a single-celled yeast to evolve into a multicelled organism. Evolution to multicellularity has occurred at least 20 times since life began, but the last time was about 200 million years ago, and it left few clues to the precise sequence of events, writes Bob Holmes for New Scientist. William Ratcliff and colleagues grew the yeast in a liquid, gently centrifuged each culture, and inoculated the next batch with the yeast that settled to the bottom of each tube. Because groups of cells settle faster than single cells, the team was able to select for yeast that clumped together. Within 60 days—about 350 generations—all their culture lines had evolved a clumped, snowflake form. "The key step in the evolution of multicellularity is a shift in the level of selection from unicells to groups. Once that occurs, you can consider the clumps to be primitive multicellular organisms," said Ratcliff. Skeptics say, however, that because some yeast strains were multicellular tens or hundreds of millions of years ago, the yeast may have retained some evolved mechanisms for cell adhesion and programmed cell death, effectively stacking the deck in favor of Ratcliff's experiment. Ratcliff and his colleagues are planning to address that objection by doing similar experiments with Chlamydomonas, a single-celled alga that has no multicellular ancestors.

Nature: Many studies have shown how some birds, such as pelicans, can conserve energy by flying in formation. However, for pigeons, flocking comes at a high energy cost. James Usherwood and colleagues at the University of London discovered this through fitting GPS sensors to the birds. They propose other factors that might explain why pigeons favor such an energy-intensive activity, such as mutual observation, collective guidance and navigation, enhanced security as a result of greater numbers of individuals or of eyes, fitness display, and assessment of group numbers.

New Scientist: In a case before a US federal court, animal rights groups are arguing that wild horses of the American West should be considered a native species and thus deserving of the same protections as elk or antelope. If the claim is successful, it could change the way the US Bureau of Land Management (BLM) manages tens of thousands of wild horses on federal lands, writes Bob Holmes for New Scientist. Although it is generally accepted that North America is the ancestral home of horses, today's wild horses are the feral descendants of domestic ones brought over from Europe centuries ago. Yet according to some researchers, whether or not the horses are native ought to be irrelevant to their treatment by the BLM. Mark Davis at Macalester College in Saint Paul, Minnesota, is lead author of a new paper in Nature that questions the valuing of native species over nonnative ones. He says the distinction between native and introduced is arbitrary: "The question should be, are wild horses causing a problem? Are they providing benefits? Then you can develop policy to either reduce or increase their numbers."

CNET: Currently the only method for thinning blood, and thus reducing the risk of heart attacks and strokes, is through drugs such as aspirin. But physicists at Temple University in Philadelphia have been working on a procedure that uses magnets. Rongjia Tao and coworkers were able to use a magnetic field of 1.3 tesla (roughly equivalent to what is used in magnetic resonance imaging) to polarize red blood cells, which contain iron, thereby causing those cells to link together in short, streamlined chains, writes Elizabeth Armstrong Moore for CNET. The blood then flowed more smoothly through the blood vessels, and the friction along the walls was reduced. The researchers found that after just 1–12 minutes of exposure to the magnetic field via a 1000-pound magnet, blood viscosity decreased by 20–30% for several hours. Eventually, blood viscosity returned to previous levels. Unlike the ionizing radiation found in CT scans, Tao’s method is not expected to have any harmful biological effects. The study is to be published in the journal Physical Review E.

National Geographic: According to a new study, nuclear radiation from bomb tests and power plant accidents causes slightly more boys than girls to be born, writes Ker Than for National Geographic. Normally, male births outnumber female births by a ratio of 105 to 100, said one of the study's coauthors, Hagen Scherb of the Institute of Biomathematics and Biometry at Helmholtz Zentrum München in Germany. The statistical bumps observed in the study are in addition to that slight natural imbalance. The study also found that while effects of nuclear incidents on the ground tend to be regional, atmospheric blasts can have a global effect. Analyzing population data from 1975 to 2007 for Europe and the US, Scherb and colleagues found two spikes in the number of male births relative to female births, which they attribute to atmospheric atomic bomb tests and the 1986 Chernobyl disaster. Despite the fact that in both instances the increase in the ratio of male-to-female births was meager—less than 1%—even such a small increase in the percentage of male births has led, over decades, to several million fewer girls being born worldwide than would otherwise have been expected. Although the biological mechanism behind the skewed sex ratio wasn't investigated in the study, previous radiation experiments on animals suggest the boost in males may be due to damage to X chromosomes in sperm, Scherb said.

Nature: Saturn's icy moon Enceladus has some of the chemical ingredients for life—liquid water, organic carbon, and nitrogen—plus a source of energy in its tectonically active crust. As Nature's Richard Lovett reports, a recent workshop held at the SETI Institute in Mountain View, California, attendees brainstormed ideas for finding life on Saturn's sixth-largest moon. Although the Cassini spacecraft is currently in orbit around Saturn and has flown by Enceladus 27 times so far, it lacks the instruments to detect the molecular signatures of life. One promising approach is to look for differences in the concentrations of carbon-12 and carbon-13 in methane and other molecules. Whereas biochemical reactions favor the lighter isotope, nonbiochemical reactions favor neither isotope.

Chronicle of Higher Education: Biophysicists Herbert Levine, José Onuchic, and Peter Wolynes are leaving their positions at the University of California, San Diego, to join a research center at Rice University in Houston, Texas. All three researchers are members of the National Academy of Sciences. At Rice they'll work on elucidating the basic science of cancer as part of a $10-million initiative funded by the Cancer Prevention and Research Institute of Texas. In an interview with the Chronicle's Josh Keller, Levine acknowledged that the financial troubles of the University of California played a role in his decision to take up the Rice offer.

MSNBC: Researchers in the growing field of bioprecipitation believe that bacteria may be what triggers rain, snow, and even hailstorms, writes Jennifer Welsh for MSNBC. Although minerals or other particulates have long been thought to cause water droplets to form, for that to happen the water needs to be much colder than is usually found in clouds. Alexander Michaud of Montana State University, who examined golf-ball-sized hailstones, found large amounts of bacteria at their centers. Brent Christner of Louisiana State University and his coworkers studied the plant pathogen Psuedomonas syringae and found that it plays an important role in snow formation all over the world, even in Antarctica; it is very good at creating ice at temperatures above the normal freezing point of water. An organism that lives on a plant, says Christner, would probably seek another plant on the ground. He adds that if it has "the ability to produce precipitation, fall down and land on a plant, [that] could be a cycle." Both Michaud and Christner presented their findings Tuesday at the general meeting of the American Society for Microbiology in New Orleans.

Daily Mail: Scientists are one step closer to creating power stations that generate electricity from humble bacteria, writes David Derbyshire for the Daily Mail. Yesterday Tom Clarke of the University of East Anglia and coworkers published their results in the Proceedings of the National Academy of Sciences. They have shown for the first time how microbes are able to discharge tiny electrical currents from their cells to get rid of unwanted electrons—the byproducts of converting food into energy. By tethering bacteria directly to electrodes, the researchers were able to tap into this potential source of electricity, although at present the currents generated are too weak to be useful. Nevertheless, because some bacteria feed off pollutants, microbial fuel cells or “bio-batteries” raise the possibility that in the future, bacteria could be used to convert industrial waste, sewage, and uranium waste into electricity.

New Scientist: A new method of analyzing a fingerprint could reveal not just its pattern but also when it was made. Many methods, including dusting, chemical agents, and atomic force microsopy, have been developed to capture fingerprints. All of them have their limitations. Now Robert Prance and colleagues at the University of Sussex in Brighton, UK, have developed a way to capture fingerprints by examining the small amount of static charge left behind when a finger makes contact with an insulating surface such as plastic or glass, writes Wendy Zukerman for New Scientist. By measuring the static charge repeatedly over a period of two weeks, the researchers, who have published their results in Forensic Science International, found that the charge decayed over time and, therefore, the measurements could be used to determine when a fingerprint was made. The technique could be used in forensics to determine when a crime was committed or to narrow a list of suspects. There are limitations, however: It won't work with prints left on a conducting material, such as a metal bullet casing.

Daily Mail: A super-resolution microscopy technique developed at Sandia National Laboratories is allowing researchers to study a cell membrane with extraordinary spatial resolution. The technique builds on super-resolution capabilities developed in recent years, but it goes another step by adding dual-color capabilities to the relatively new stochastic optical reconstruction microscopy, or STORM. Sandia researchers Jesse Aaron, Jeri Timlin, and Bryan Carson have been using the new technique to discover why a cell can defend against some invaders, such as Escherichia coli, while failing against others, such as the bacteria that cause bubonic plague. They have been able to view the clustering of receptor proteins—tasked with recognizing intruders—on the surface of immune cells when those proteins are confronted with lipopolysaccharides derived from E. coli; LPS derived from bacteria that cause the plague do not cause the same effects. Such studies could open doors to new diagnostic, prevention, and treatment methods. For more details, see Sandia’s press release.

BBC: Tardigrades, also known as water bears, joined the crew of the space shuttle Endeavour on Monday as part of Project Biokis, sponsored by the Italian Space Agency. The project will investigate the impact of short-duration spaceflight on several different microscopic organisms; Tardkiss, a subset of the project, will expose tardigrade colonies to different levels of ionizing radiation at different points during the spaceflight. The data will be used to help determine how radiation dosage affects the way cells work. Less than one millimeter long and ubiquitous on Earth, water bears became the first animals to survive exposure to space during the European Space Agency's 2007 Foton-M3 mission. In inhospitable conditions, they enter a state of dormancy called cryptobiosis—an ametabolic state that allows them to resist physical and chemical extremes, including solar winds, high pressure, and the vacuum of space. The Tardkiss study may facilitate the development of techniques to protect other organisms, including humans, from the extreme stresses encountered during space exploration.

Wired: Birds, amphibians, and mammals often use hard-to-discern sounds to add an extra layer of vocal information, but until now such sounds had not been detected in fish, writes Dave Mosher for Wired. In a new study published in Proceedings of the Royal Society B, Aaron Rice, a biologist at Cornell University, and coworkers analyzed the vocalizations of the three-spined toadfish. Swim bladders, air-filled sacs that allow the toadfish to alter its buoyancy, also serve as sonic instruments when the fish vibrates the muscles in the sacs. The researchers found that the sound produced contains surprisingly complex information, including subtle harmonics and dissonances.

Wired: New video footage of hummingbirds drinking has revolutionized scientists’ understanding of the process. “The first time I saw these videos, they blew my mind,” said Alejandro Rico-Guevara from the University of Connecticut, one of the coauthors of a study published in the Proceedings of the National Academy of Sciences. It had been believed that capillary action drew the fluid up a pair of tubes in the hummingbird’s tongue, but the video shows instead that the tongue’s tip acts as a liquid-trapping device. For the study, Rico-Guevara and colleague Margaret Rubega built transparent flowers. They then filmed high-speed, magnified footage of hummingbirds’ tongues flicking into the nectar. Instead of simply sucking up the nectar, the tongue’s two tubes, which are initially curled at the tip of the tongue, uncurl when they come in contact with the nectar; when the tongue is retracted, they curl back up to trap the nectar and pull it back into the beak. Studies of this mechanism could aid in the design of self-assembling electronics, fluid-power microchips, or even liquid-sipping robots.

Science: Traditional microscopes can't resolve objects smaller than half the wavelength of the light used to illuminate them; electron microscopes get around this by replacing the visible light with electron beams, which have a much shorter wavelength and a much smaller intrinsic blur. However, electrons pass right through thin samples of most living tissue unless it's been prepared in a radical way—which prevents researchers from viewing living organisms. E. G. van Putten, of MESA+ Institute for Nanotechnology in Twente, the Netherlands, and colleagues etched a gallium phosphide lens with sulfuric acid to produce a frosted surface that scattered light in all directions. They then used a computer to design a light wave that, when passed through and scattered by the lens, would focus to a point. It seems counterintuitive, but the randomization and reconstruction process allowed the researchers to form a sharper image than would otherwise have been possible. They were also able to create an ultrasharp image of the entire sample by rotating the incoming light wave and scanning the focus across the sample. Thus far, they have imaged gold nanoparticles with a resolution as small as 97 nm. With a more powerful light source and some fine-tuning, it should be possible to see details of living tissue samples, including nanoscale processes such as viruses invading cells.

New Scientist: Two techniques involving magnets could significantly reduce the time it takes—from days to hours—to diagnose a fatal infection, writes Jessica Hamzelou for New Scientist. A team at MIT has created a device that uses magnetic resonance to detect a fungus called Candida, which has a 40% mortality rate. Because there are five species of Candida, the team engineered five types of molecular probe, each of which contains a magnetic particle. When the probes are put into blood samples and a magnetic pulse is applied, the water molecules begin to spin; the time it takes for the molecules to return to rest determines whether a species of Candida is present and how much of it there is. A second team at Harvard University has been working to diagnose sepsis. Team members coated magnetic particles with an immune-system protein that binds to the cell walls of pathogens in the blood. The entire cluster can be pulled out using a magnet, and the pathogen can then be identified. "In my opinion both techniques could significantly advance the field of diagnostics.... It's pretty cool," said Dirk Kuhlmeier at the Fraunhofer Institute for Cell Therapy and Immunology in Leipzig, Germany.

Science: Current crowd simulations, used to develop safe public spaces, usually treat virtual humans within the model as simple particles that repel each other and zoom to their destinations. While these models are useful for predicting how long pedestrians might take to cross an intersection, they cannot reconstruct or predict the chaotic movement of a large number of people trying to escape a crowded room. Mehdi Moussaid, of the University of Toulouse, France, and colleagues created a computer model that emphasizes human behavior rather than many-body physics. The model doesn’t ignore physical laws, such as the person-to-person energy transfer that help explain “crowd-quakes”, but it does rely on heuristic formulas the team derived from studying patterns of pedestrian movement in videos. Moussaid's approach is the first to accurately reproduce pedestrian behavior across a spectrum of intensity: from lanes of pedestrians formed in simulations of hallway interactions to emergency escapes from bottlenecked rooms.

Science: Research has indicated that sonar and other anthropogenic sounds can damage a wide spectrum of ocean fauna, but the effect of such sound on cephalopods was unknown. Now Michel André of the Technical University of Catalonia in Spain and colleagues have been studying the effect of high-decibel, low-frequency sound on wild cephalopods held in laboratory aquariums, and discovered that all of the animals exposed to the noise suffered severe damage to their statocysts (sound-detecting structures behind the cephalopod eye). Damage ranged from crumpled or displaced sensory cells to large lesions. More damage appeared to develop as post-exposure times increased. Peter Madsen at Aarhus University in Denmark expresses some skepticism about the results, partly because the control animals used by the researchers were not housed in an aquarium as the experimental animals were, which leaves open the possibility that captivity caused or contributed to the sensory damage in the latter group. T. Aran Mooney at Woods Hole Oceanographic Institution in Massachusetts questions how André and his team measured the animals' exposure to noise, but also says their research is "a good first step" in determining whether anthropogenic noise harms cephalopods.

BBC: Sensors placed on the outside of the human skull can pick up enough information from the brain beneath to direct, say, a cartoon car around a crude course on a computer screen. But the skull absorbs high-frequency signals that would allow finer, faster control. Now, Eric Leuthardt of Washington University in Saint Louis and his collaborators have shown that sensors placed directly on the surface of a person's brain can be used to move a computer cursor with pure thought, as if the person were using a mouse. The people in the study were epilepsy patients who'd already had the electrocorticographical sensors implanted in their heads. Controlling the cursor entailed asking the patients to think of four vowel sounds. After recording the signals that corresponded to each imagined vowel, the researchers ran a control program that translated the signals into cursor motion.

New York Times: In India, writes Andrew Revkin for the New York Times, cheap technology is widening the gender gap—but not the kind related to jobs and salaries. A combination of rising incomes, availability of ultrasound, and cultural norms that strongly favor boys over girls has resulted in a distorted ratio of female to male children in that country. In 1991 the ratio was 945:1000, in 2001 it was 927:1000, and this year it’s 914:1000. And India is not the only country where this is occurring—China and Vietnam are witnessing a similar trend. For more on the subject, read Diksha Sahni's blog post for the Wall Street Journal.

Washington Post: As Washington, DC, celebrates its National Cherry Blossom Festival this week, the Post's Brian Palmer interviewed Ove Nilsson of Sweden's Umea Plant Science Center concerning the genetic basis for when the plants bloom. According to Nilsson, the blossom festival started last June, when the buds were actually initiated. The longer days of summer kick-start the growth processes by allowing a molecule in the plants' cells, the FT protein, to be produced. Winter's shorter days signal the plants to go dormant. In the spring, however, it is not the longer days but rather the warmer temperatures, Nilsson has found, that signal the blossoms to open. Thus global warming could challenge the system, for two reasons: It could throw off the plants' ability to sense spring and disrupt the pollination schedule of bats, birds, and bees, which spread the plants' seeds.

New Scientist: A company based in Australia has been working on a cochlear implant for the hearing impaired. Unlike a traditional hearing aid, which acoustically amplifies sound, the bionic device translates sound into electrical signals that are used to electrically stimulate the cochlea—a spiral-shaped part of the inner ear attached to the auditory nerve, writes Duncan Graham-Rowe for New Scientist. Because of its small size, the new device can be fully implanted in a patient's ear—unlike current devices, which require an external unit containing the power supply, processors, and microphone. The fully implantable system, would, however, require replacement every 10 years when its batteries run out.

Science News: Harvard physicists have described for the first time how flowers generate the forces needed to curl open come springtime, writes Daniel Strain for Science News. In their 21 March article published online in the Proceedings of the National Academy of Sciences, Haiyi Liang and L. Mahadevan studied the asiatic lily and how its petals and sepals—the outer, greener portion of a flower—gradually invert, then peel open like a banana and form a blossom. The Harvard team’s first clue to the mechanism was that the outer margins of petals and sepals ruffled during blooming, while inner surfaces stayed smooth. The researchers also developed a mathematical model to demonstrate how extra edge strain could warp thin materials like flower petals. “Infusing a scientific aesthetic into a thing of beauty only enhances our appreciation of it,” Mahadevan said. “This is what we try to do as scientists.”

Science: Some in the field of taxonomy are hoping to make use of amateur scientists much as the popular GalaxyZoo has done with citizen astronomers. As funds and professional practitioners dwindle, and the number of extinctions rises, scientists are pushing to identify and catalog organisms. Proponents of the plan to use amateurs say that although taxonomy has grown to be quite specialized, technological advances are helping lower the bar for participating. There are already several science programs that take advantage of amateurs’ input: among them Project Feeder Watch, which asks the public to identify backyard birds, and Encyclopedia of Life, which seeks photos, videos, and information on all forms of life. Others fear that research quality could suffer if amateurs flock to “attractive” creatures such as birds and beetles and ignore the less attractive ones, such as jellyfish and nematodes.

BBC: A team from the US and Canada has built a miniaturized scanner that can perform positron emission tomography (PET) on mobile, wide-awake rats. The new scanner, which is described in a paper in Nature Methods, is potentially useful because PET is a molecular probe. Thanks to the use of radioactive tracers, PET can locate concentrations in the brain of neurotransmitters and other biochemically significant molecules. Subjecting lab rats to PET scans usually entails immobilizing and anesthetizing them, a restriction that limits the kinds of brain activity that can be studied. The new scanner is small enough and light enough that it can be attached to a rat's head while the rat moves about.

Nature: The acidity of seawater has climbed by 30% over the past 150 years, and some regions have already become corrosive enough to inhibit the growth of corals and other species for part of the year. Carbonic acid is produced when the oceans absorb carbon dioxide, which reacts with the water. Unless nations sharply curb their emissions, atmospheric CO₂ is expected to at least double from its preindustrial concentration by sometime in the second half of this century. Countries are only now revving up the coordinated research programs needed to assess how marine ecosystems will react to the increasingly acidic waters. Quirin Schiermeier examines this problem in his Nature news story.

Washington Post: NASA has taken the unusual step of disclaiming any endorsement of a paper written by one of its scientists, Richard Hoover of Marshall Space Flight Center in Huntsville, Alabama. The paper, which appears in the online Journal of Cosmology, claims that tiny, wormhole-like cavities in the Alais, Ivuna, and Orgueil meteorites constitute evidence of extraterrestrial bacteria. As Seth Borenstein of the Associated Press reports, other scientists are skeptical, given how easily the meteorites could have become contaminated. "There has been no one in the scientific community, certainly no one in the meteorite analysis community, that has supported these conclusions," NASA Astrobiology Institute Director Carl Pilcher said of Hoover's analysis.

BBC: Researchers in the UK and Singapore have demonstrated the highest-resolution optical microscope ever—imaging objects down to just 50 nanometers. Ordinarily, it's impossible to use visible light to resolve objects smaller than its wavelength (380–750 nm). However, you can beat this diffraction limit by detecting "evanescent" waves, whose intensity falls to zero within one wavelength of the emitter's surface. As reported in Nature Communications, the new technique uses tiny glass beads to gather evanescent light waves and refocus them, channeling them into a standard microscope. It is believed that the technique holds great promise for biological studies, for viewing cells, bacteria, and viruses.

BBC: Nitrogen is the fourth most abundant element in the universe, the most abundant gas in Earth's atmosphere, and an essential ingredient in proteins, DNA, and other biomolecules. But getting nitrogen into the right chemical form to give rise to life is chemically tricky. Now, Sandra Pizzarello of Arizona State University and her colleagues have found a possible answer. By using hot, pressurized water, Pizzarello was able to dissolve and subsequently analyze an otherwise insoluble organic component of a meteorite found in Antarctica. Among the molecules they found was ammonia. Unlike N₂, ammonia readily participates in organic chemistry. Pizzarello speculates that meteorites could have brought ammonia to prebiotic Earth, thereby giving life the chemical impetus needed to get going. The team reported their results in the Proceedings of the National Academy of Sciences.

Science News: By using a combination of computer simulation and lizard-mimicking robots, Daniel Goldman of Georgia Tech and his colleagues have determined how the sandfish lizard is able to burrow at a maximum rate of two body lengths per second through a sandy medium. Optimization of the lizard's wiggling motion is the key. The bigger the amplitude of the lizard's wiggles, the more force the lizard exerts on the sand. But that increased force, being side to side, doesn't yield faster forward motion. A medium wiggle is optimal. The problem of determining the sandfish lizard's motion reflects the challenges of understanding granular media, which share some properties with solids and others with liquids. Goldman's paper is scheduled to appear in the journal Royal Society Interface.

Guardian: Biology is providing surprising insights into the financial crisis that brought the banking system to its knees, according to Ehsan Masood, editor of Research Fortnight. Over a period of several weeks, Masood worked with biologists who were advising the Bank of England on how to reform global finance, as part of a documentary for BBC Radio 4. Ecologist and former government chief scientific adviser Robert May and others made the case that the most stable ecosystems are those with a diversity of species; less stable ecosystems have less diversity and a higher degree of connectedness between species. Their results, published in Nature, revealed that the banking system was relatively homogeneous—with many banks having similar characteristics and doing the same things—and also super-connected.

NPR: The scientific evidence alone is not enough to prove that microbiologist Bruce Ivins was the perpetrator of the anthrax attacks that killed five people in 2001, according to an independent review panel, writes Joe Palca for NPR. The panel of scientists was convened by the National Research Council of the National Academies to review the science that the FBI used in its investigation into the attacks. After the attacks, the FBI created the Amerithrax Task Force, which interviewed thousands of witnesses and evaluated a mountain of evidence. Ivins killed himself in July 2008, just as the Justice Department was about to indict him.

Science: The exoskeletons of ants, ticks, and other arthropods, both ancient and modern, are made up of proteins, sugars, and calcium carbonate. When an arthropod dies, microbes begin eating the first two components of the shell. The upshot for paleontologists is that little of an ancient arthropod's exoskeleton survives as a fossil. But some exoskeleton does survive, and now, as Science's Sid Perkins reports, we know why. George Cody of the Carnegie Institution of Washington and his collaborators applied x-ray absorption near edge structure (XANES) spectromicroscopy to the fossilized remains of two arthropods, a 310-million-year-old land scorpion and a 417-million-year-old sea scorpion. Comparison with modern scorpions revealed that what remained of the fossilized exoskeletons had been chemically modified, possibly by chemicals from the exoskeleton's original waxy coating. When the scorpions were alive, the waxy coating prevented their exoskeletons from drying out. When they died, the coating decomposed, releasing chemicals that stabilized the exoskeleton's protein–sugar complex.

BBC: Researchers at Cambridge University have identified the mechanism by which fleas jump up to 200 times the length of their bodies. Fleas make use of a spring, rather than their muscles, to store jumping energy in their hind legs. What was in question was how the energy is released. In a paper that appears in the Journal of Experimental Biology, zoologists Gregory Sutton and Malcolm Burrows report the results of a study that entailed both modeling a flea's legs and filming fleas as they jump. The researchers conclude that the spring delivers its impulse via the explosive extension of a flea's tibia (shin) and tarsus (foot), rather than through its trochanter (knee).

Science News: Deep within Earth, bacteria and other tiny organisms can coax the rocks around them to produce food, say researchers whose findings appear in the March issue of Geology. They have found that the mere presence of microbes triggers minerals to release hydrogen gas, which the organisms then ingest. “It looks like the bacteria themselves have an integral role in liberating this energy,” says R. John Parkes, a geomicrobiologist at Cardiff University in Wales. The work helps explain how microbes can survive up to kilometers deep in a subterranean world far from any sunlight to fuel photosynthesis.

BBC: In a paper published in the Journal of the Royal Society Interface, Peter Falkingham of the University of Manchester and his collaborators explain why fossilized dinosaur footprints are so rare. According to the group's computer simulations, the massive prehistoric animals left enduring prints only in thick, shallow mud. Lighter dinosaurs would not leave prints in the same kind of mud, which means that the absence of small prints next to large fossilized prints should not be taken as evidence for the absence of small dinosaurs.

New York Times: Researchers at Colorado State University said Wednesday that they were working on developing a plant-kingdom early warning system: plants that subtly change color when exposed to minute amounts of TNT in the air. The research, published in the peer-reviewed online science journal PLoS One, and financed mostly by the Departments of Defense and Homeland Security, shows that plants are uniquely suited by evolution to chemical analysis of their environment, in detecting pests, for example. The trick, still in refinement, writes the New York Times's Kirk Johnson, is how to make sure the plant’s signal is clear enough and fast enough to be of use.

New Scientist: James Urquhart, writing for New Scientist, describes a camera inspired by the operation of the human eye. The camera can zoom without the need for bulky lenses, making it more compact than conventional cameras. The device builds on a non-zooming eyeball camera developed in 2008 by John Rogers of the University of Illinois at Urbana-Champaign. Now he has given the technology a twist by building in a stretchable lens and a flexible photodetector whose shape alters as the magnification of the lens changes. The technology could be used in such devices as night-vision cameras and endoscopes.

Daily Mail: NASA scientists have reported finding the amino acid isovaline in samples of meteorites that came from asteroids. This discovery suggests that life on Earth began in space, because most of the isovaline from the meteorites was left-handed and life on Earth uses the left-handed kind of amino acid exclusively. This suggests that perhaps left-handed life got its start in space, where conditions in asteroids favored the creation of left-handed amino acids. Life in other star systems with different early conditions could have built up around right-handed amino acids, said NASA’s Daniel Glavin.

Science: By sequencing the nuclear genome of an ancient finger bone, researchers have confirmed the discovery of a new type of human that lived in the Altai Mountains in southern Siberia more than 30 000 years ago. The long-lost group of people, which researchers are calling "Denisovans" after the Denisova cave in which the bone was found, lived at roughly the same time modern humans and Neandertals were in the region, and it appears to be more closely related to Neandertals than us. Although the Denisovans went extinct, they were widespread enough in Asia to interbreed with modern humans before they disappeared, writes Science’s Ann Gibbons.

New Scientist: Researchers in Germany have designed a tiny camera, inspired by an arthropod eye, that maximizes image resolution. Andreas Brückner, of the Fraunhofer Institute of Applied Optics and Precision Engineering, and colleagues constructed an electronic cluster eye that can take 221 miniature images, each 39 pixels to a side, that are then stitched together into a single image of 700 by 550 pixels, writes New Scientist’s Kate McAlpine. The tiny device, which can provide clear, high-resolution images, could be used in cell phones, in medical devices, or on the gripper hands of robots as a secondary eye.

Nature: Himadri Pakrasi of Washington University in St. Louis and his collaborators have discovered that the photosynthesizing bacterium Cyanothece 51142 makes hydrogen. The enzyme responsible, nitrogenase, is present in other bacteria, which, like Cyanothece 51142, use it to make ammonia and its byproduct, hydrogen. Because nitrogenase breaks down in the presence of oxygen, those other bacteria have to live in oxygen-poor environments. Cyanothece 51142, by contrast, consumes the oxygen within its cell walls during photosynthesis. The ability of Cyanothece 51142 to live in oxygen-rich environments could make it a useful source of hydrogen fuel for cars and other machines.

Guardian: : The RMS Titanic, which sank almost 100 years ago, is slowly being eaten away by a newly identified species of bacterium, Halomonas titanicae, which lives in “rusticles” affixed to the ship’s hull. A rusticle is a structure that looks like an icicle but consists of rust and is highly porous; rusticles can support a complex variety of bacteria. While H. titanicae could pose problems for offshore oil and gas pipelines, it could be useful in the disposal of old ships and oil rigs that have been cleaned of toxins and oil-based products, according to researchers at Dalhousie University in Halifax, Canada, and Seville University in Spain.

BBC: Leslie Noble of the University of Aberdeen and his collaborators have analyzed the DNA of great white sharks in the Atlantic Ocean, the Indian Ocean, and the Mediterranean Sea and reached a startling conclusion. The great whites in the Mediterranean are more closely related to their counterparts in the distant antipodes than to their counterparts in the nearby Atlantic. Moreover, because random genetic mutations occur at roughly the same rate, Noble and his team could deduce that the Mediterranean and Indian Ocean populations diverged 450 000 years ago. At that time, Earth was between ice ages. Strong currents could have taken some Indian Ocean sharks to the Mediterranean, which was more accessible than it is today. Because sharks spawn where they were born, the first generation of Mediterranean sharks would have stayed and not tried to find their way back. The results appear in the Proceedings of the Royal Society B.

Washington Post: David Mann of the University of South Florida and his collaborators have adapted a technique used to test the hearing of infants and applied it to beached or stranded dolphins. By measuring the electrical impulses evoked by an auditory stimulus, Mann and his team discovered that some beached or stranded dolphins are deaf. As the researchers report in a paper in PLoS One, the deafness appears to depend on species:

Approximately 57% of the bottlenose dolphins and 36% of the rough-toothed dolphins had significant hearing deficits with a reduction in sensitivity equivalent to severe (70–90 dB) or profound (>90 dB) hearing loss in humans. The only stranded short-finned pilot whale examined had profound hearing loss. No impairments were detected in seven Risso's dolphins from three different stranding events, two pygmy killer whales, one Atlantic spotted dolphin, one spinner dolphin, or a juvenile Gervais' beaked whale.

Mann notes there are five possible causes of hearing loss in dolphins: intense chronic noise, transient intense noise, age-related hearing loss, congenital hearing impairment, and the side effects of certain antibiotics that are given to sick, stranded dolphins. Because dolphins rely on hearing to find food, Mann argues "that hearing screening should be part of the standard veterinary examination of stranded cetaceans." A deaf dolphin, even if it recovers from being stranded, is unlikely to fare well when returned to the sea.

NPR: By the end of next year, one out of every six airline passengers at US airports will be asked to go through a scanner that uses backscattered x rays to find concealed weapons. In absolute terms, the radiation dose delivered to each passenger in one scan is tiny: 0.02 microsieverts, about 1/1000th of the dose the same passenger would receive from cosmic rays during a transcontinental flight. But, as NPR's Richard Knox reported earlier this year, a group of biochemists and biophysicists from the University of California, San Francisco, has challenged the assumption that the scanners are safe, despite the low dose. The scientists question whether the prime safety criterion should be the overall dose, if, as they suspect, the dose is concentrated in the passenger's skin.

Nature: Daniel Zalko of the French National Institute for Agricultural Research in Paris and his colleagues have used radioactive tracers to prove that bisphenol A (BPA) is readily absorbed through the skin. The chemical, which is widely used as an additive in plastics and other consumer products, has been banned in Canada because of its implication in a range of medical conditions, including birth defects. Zalko and company's findings might help clear up a mystery. Some people have higher levels of BPA in their bodies than would be expected if they ingested it in food or drink. Among the BPA-containing products that people routinely touch is the thermal paper used for store receipts.

New Scientist: Researchers at the University of Oxford report in Current Biology that applying an electric current to a particular area of the human brain can improve mathematical abilities for at least six months. Roi Cohen Kadosh’s team applied transcranial direct current stimulation to the right parietal cortex while simultaneously using the opposite current to subdue activity in the left parietal cortex. "This isn't going to turn you into a genius," said Cohen Kadosh, "but it could be turned into a device to help children with poor numeracy skills improve their mathematical abilities."

BBC: A collaboration between the University of Tübingen and Retina Implant AG—both in Germany—has successfully tested a chip that, once installed behind a damaged retina, can partially restore a blind person's sight. As the BBC's Neil Bowdler explains, the sub-retinal chip works like an undamaged retina. Light focused by the eye's lens strikes the chip, which converts the energy into electrical impulses and sends them to the optic nerve.

SPACE.com: Genomics pioneer J. Craig Venter asserts that human space exploration could benefit from more genetic screening and genetic engineering. Genetic screening could help better identify individuals most suited for long space missions, by identifying certain genes that would be desirable, such as ones that encode robust bone regeneration or rapid repair of DNA. Genetic engineering could make space travel safer and more efficient, by engineering microbes to help astronauts take up nutrients more efficiently or to eliminate body odor, for example. However, engineering humans would only come after long consideration and debate, Venter said.

BBC: In a paper in the latest issue of Nature, Caltech's Moran Cerf and his collaborators report experiments that directly probed how our imaginations can shape, and even override, what our senses tell us. Cerf's team looked at the output from detectors attached to single neurons in the brains of 12 epilepsy patients. The patients were shown hybrid images of actors Josh Brolin and Marilyn Monroe and asked to "see" one or the other—that is, to mentally change what was before their eyes. Having already determined which neurons hold either image, Cerf and his team could tell that the patients could reliably override the hybrid image and "see" the image of the requested actor. According to Cerf, his findings suggest that it might be possible one day to record people's dreams.

Guardian: One of science's longest-running imaging competitions, the Nikon Small World awards, has announced the 2010 winners. Celebrating its 35th anniversary, the competition received entries from scientists in 63 countries. This year's first prize went to Jonas King, of the biological sciences department of Vanderbilt University in Nashville, Tennessee. He used fluorescence microscopy to capture his close-up view of the heart of a mosquito (see image below). To see all the winning images, visit the Nikon Small World online gallery.

Space.com: A new type of greenhouse is being refined for future lunar or Martian colonies to grow fresh fruit and vegetables. Scientists at the University of Arizona’s Controlled Environment Agriculture Center (CEAC) built a prototype lunar greenhouse where plants are grown without either soil or sunlight: Potatoes and other vegetables are grown in water—hydroponically—and are buried in a module beneath a planet’s or moon’s surface to protect them from harmful radiation; they receive light from sodium vapor lamps in the module. The system would operate independently and would use robot-like components. A similar CEAC food-production system has been operating at a South Pole research station for the past six years.

Science News: Scientists at the Johns Hopkins University have created millimeter-sized machines that operate without batteries or any other source of power. Engineer David Gracias and coworkers, who published their results in the Journal of the American Chemical Society, developed the tiny tools, which have five finger-like extensions that snap shut when exposed to a certain chemical or combination of chemicals. Their invention could have medical applications such as to biopsy tiny bits of tissue or to deliver small amounts of drugs to disease sites in the body.

New York Times: The mystery of what is killing off the honeybees may have been solved by a unique partnership of military scientists and entomologists. Since 2006, 20–40% of US bee colonies have disappeared. The probable reason: A fungus tag-teaming with a virus have apparently interacted to cause the problem, according to a paper by US Army scientists in Maryland and bee experts in Montana in the online science journal PLoS One. The scientists say that more research is needed to determine, for example, how further outbreaks might be prevented, and how much environmental factors such as heat, cold or drought might play a role.

New York Times: The three-dimensional imaging techniques of the movies are being used to improve athletic performance. Motion capture produces a 3D image on a computer using a combination of advanced sensors, biomechanics, orthopedic research, and animated-film technology such as that used in the film Avatar (2009). The images generated, which can be viewed from any direction, provide a wealth of data regarding limb angles, ball speeds, and g-forces. Some of the innovative uses of the new technology include sports players studying their peak performances to improve their technique and avoid injury, dancers in different locations being able to practice with each other using 3D re-creations, and coaches working remotely with teams by watching them perform drills in three dimensions in another location.

Economist: A group of oceanic microorganisms may hold the key to fighting climate change, according to Jiao Nianzhi of Xiamen University in China and his colleagues. Jiao and his team note that carbon dioxide is absorbed by the ocean through photosynthesis by planktonic algae, which lie at the bottom of the food chain. The algae are consumed by tiny animals, which are in turn consumed by larger ones. Eventually this organic matter makes its way to the ubiquitous aerobic anoxygenic photoheterotrophic bacteria (AAPB), which convert the carbon contained in it into a compound that cannot be turned back into carbon dioxide. Thus, the AAPB build up a reservoir of carbon in the ocean and keep it out of the atmosphere. The researchers are looking into encouraging the growth of planktonic algae, and hence AAPB, in order to take advantage of this microbial carbon pump that could potentially be used to combat climate change by extracting carbon dioxide from the atmosphere.

Los Angeles Times: An appeals court in Washington, DC, ruled yesterday that the National Institutes of Health may temporarily resume funding research that involves human embryonic stem cells. NIH had halted research last month in response to a court-ordered injunction that stated that federal funds cannot be used for such purposes. "We are pleased with the court's interim ruling, which will allow this important, life-saving research to continue while we present further arguments to the court in the weeks to come," said NIH Director Francis Collins.

Science: Possibly unprecedented in its history, the National Institutes of Health yesterday ordered a shutdown of human embryonic stem cell experiments by researchers in labs on the NIH campus. According to Jocelyn Kaiser of Science, the message came from NIH intramural research chief Michael Gottesman. The action was a response to a court-ordered injunction a week ago, which stated that using NIH funding to study human embryonic stem cells violates a law prohibiting the use of federal funds to destroy embryos.

Nature: Harvard University’s Charles Lieber and his colleagues have developed an electrical probe that’s so tiny it can be inserted into a cell’s membrane without disrupting it. To make the probe, Lieber’s team took a silicon nanowire, bent it into a hairpin, coated it with lipids (the same type of molecules make up the membrane), and attached it to a tiny field-effect transistor. A paper describing the probe’s fabrication, operation, and performance appears in today’s issue of Science.

Smithsonian: Sensor-studded clothing, a Band-Aid-sized electrocardiogram machine, and computer screens in contact lenses—such miniature embedded electronics may one day be possible, provided the right power supply can be developed. As Michael Belfiore explains in the August issue of Smithsonian magazine, current batteries are too bulky for those applications. Researchers at MIT are therefore working to harvest thermal and kinetic energy from the human body, which they hope can be converted into electricity and stored in a capacitor on a millimeter-sized chip. So, in future, just walking or nodding your head could power, say, a cell phone implanted in your tooth.

New York Times: It’s long been appreciated that the vivid colors of butterfly wings arise not from pigments, which selectively absorb certain frequencies, but from intrinsic microstructures, which selectively refract certain frequencies. Now, Yale University’s Richard Prum and his collaborators have figured out how those microstructures grow as the butterfly develops inside its chrysalis.

Nature: An elastic polymer has been made whose molecular structure mimics that of titin, a protein found in muscle. The resulting material is tough and stretchy and dissipates energy — just like muscle itself.

Physics Today: Rice University undergraduates Lila Kerr and Lauren Theis have developed a rudimentary blood centrifuge that does not require electricity, by adapting a standard salad spinner.

Nature: Dorothy Hodgkin was born 100 years ago next month. When Hodgkin won the Nobel Prize in Chemistry in 1964, much was made of her gender. She was only the fifth woman to become a laureate in science, the first from Britain, and the first women not married to a scientist.

Hodgkin was therefore by definition exceptional. When Georgina Ferry began to write her biography soon after her death in 1994, one of her principal motives was to try to understand what it was that had enabled her to transcend the conventions of her time. "She never acknowledged that she faced barriers on the grounds of her gender," writes Ferry, "and her story largely bears this out."

What did influence her social and scientific circumstances were also exceptional, and provided the environment in which it was possible for her to fulfil her promise and achieve science's highest honor, says Ferry. The support of her parents, and the forward-thinking planning of Somerville College in Oxford.

The Frederick News-Post Online: It is absolutely impossible that Bruce Ivins, accused of mailing anthrax and killing five people in 2001, could have created and cleaned up anthrax spores in the timeline and manner the FBI alleges, Ivins's former coworker said last Thursday.

The National Academy of Sciences brought in Henry Heine, a former microbacteriologist for the US Army Medical Research Institute of Infectious Diseases, to explain spore preparation to the panel, which is tasked with investigating the science the FBI used to accuse Ivins, also a former microbacteriologist for USAMRIID.

And though Heine discussed only scientific methods and technologies before the panel, he said afterward he firmly believes Ivins did not and could not have grown and prepared the anthrax.

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Scientists raise queries over FBI anthrax probe

ScienceNOW: If efficiency were all that matters, animals would hobble around like pirates with two peg legs. That's because, mathematically speaking, running with stiff legs requires less energy. But humans and many other animals have "squishy" legs, and a new simulation suggests why. When attached to real, floppy bodies, so-called compliant legs prove more efficient, absorbing more force and offering more stability in rough terrain. The finding helps explain the long-puzzling paradox of why animals crouch and bounce as they run and may change how researchers model animal locomotion.

Nature: Gold nanoparticles coated with a thin layer of an oxide allow molecules adsorbed on surfaces of materials as diverse as platinum, yeast cells, or citrus fruits to be characterized routinely in the laboratory through the use of spectroscopy.

Related link
Shell-isolated nanoparticle-enhanced Raman spectroscopy

Science News: Evidence for the existence of Earth's magnetic field has been pushed back about 250 million years, new research suggests. The field may therefore be old enough to have shielded some of the planet's earliest life from the Sun's most harmful cosmic radiation.

NYTimes.com: Specialists say such safeguards, such as ear muffs at loud stadiums, are critical for young ears in a deafening world. Hearing loss from exposure to loud noises is cumulative and irreversible; if such exposure starts in infancy, children can live “half their lives with hearing loss,” said Brian Fligor, director of diagnostic audiology at Children’s Hospital Boston.

AAAS Meeting: Margaret Murnane and Henry Kapteyn group at JILA, a joint institute of the University of Colorado at Boulder and NIST, has made some breakthroughs on how to build a tabletop x-ray laser. The laser could be used for super high-resolution imaging, while also giving scientists a new way to at the nanoscale at objects such as a single cell.

Murnane and Kapteyn presented highlights of their research at the American Association for the Advancement of Science annual meeting in San Diego.

"Our goal is to create a laser beam that contains a broad range of x-ray wavelengths all at once that can be focused both in time and space," Murnane said. "If we have this source of coherent light that spans a huge region of the electromagnetic spectrum, we would be able to make the highest resolution light-based tabletop microscope in existence that could capture images in 3-D and tell us exactly what we are looking at. We're very close."

Most of today's x-ray lasers require so much power that they rely on fusion laser facilities the size of football stadiums or larger, making their use impractical. Murnane and Kapteyn generate coherent laser-like x-ray beams by using an intense femtosecond laser and combining hundreds or thousands of visible photons together with a desktop-size system.

They can already generate laser-like x-ray beams in the soft x-ray region and believe they have discovered how to extend the process all the way into the hard x-ray region of the electromagnetic spectrum.

"If we can do this, it could lead to all kinds of possibilities," Kapteyn said. "It might make it possible to improve x-ray imaging resolution at your doctor's office by a thousand times. The x-rays we get in the hospital now are limited. For example, they can't detect really small cancers because the x-ray source in your doctor's office is more like a light bulb, not a laser. If you had a bright, focused laser-like x-ray beam, you could image with far higher resolution."

Their method can be thought of as a coherent version of the x-ray tube, according to Murnane. In an x-ray tube, an electron is boiled off a filament, then it is accelerated in an electric field before hitting a solid target, where the kinetic energy of the electron is converted into incoherent x-rays. These incoherent x-rays are like the incoherent light from a light bulb or flashlight—they aren't very focused.

In the tabletop setup, instead of boiling an electron from a filament, they pluck part of the quantum wave function of an electron from an atom using a very intense laser pulse. The electron is then accelerated and slammed back into the ion, releasing its energy as an x-ray photon. Since the laser field controls the motion of the electron, the x-rays emitted can retain the coherence properties of a laser, Murnane said.

Being able to build a tabletop x-ray laser is just the beginning, said Kapteyn.

"An analogy that is pretty close to what is going on in this field is the MRI, which started as just a fundamental investigation," said Kapteyn. "People then started using it for microscopy, and then it progressed into a medical diagnostic technique."

The Economist: The great hope of transplant surgeons is that they will, one day, be able to order replacement body parts on demand. That possibility may be closer with the arrival of the first commercial 3D bio-printer for manufacturing human tissue and organs.

The new machine, which costs around $200,000, has been developed by San Diego–based Organovo, a company that specializes in regenerative medicine, and an Australian engineering and automation firm called Invetech.

To start with, only simple tissues, such as skin, muscle, and short stretches of blood vessels, will be made for research purposes.

Organovo expects that within five years, once clinical trials are complete, the printers will produce blood vessels for use as grafts in bypass surgery.

WSJ.com: Scientific revolutions are often led by the youngest scientists, and yet such innovation in the US could be at risk, says Jonah Lehrer in the Wall Street Journal, as the number of successful young scientists is dramatically shrinking.

In 1980, the largest share of grants from the National Institutes of Health went to scientists in their late 30s. By 2006 the curve had been shifted sharply to the right, with the highest proportion of grants going to scientists in their late 40s. This shift came largely at the expense of young scientists.

In 1980, researchers between the ages of 31 and 33 received nearly 10% of all grants; by 2006 they accounted for approximately 1%. And the trend shows no signs of abating: In 2007, the most recent year available, there were more grants to 70-year-old researchers than there were to researchers under the age of 30.

Nature News: The burning of fossil fuels such as coal and oil releases carbon dioxide that alters the balance of carbon isotopes naturally found in the environment—an effect that is now being found in food, reveals a US study.

New Scientist: Gil Bub and Peter Kohl's team at the University of Oxford wanted to record rat heart cells in action, so they trained two cameras on tissue samples in their lab. A high-speed movie camera filmed the cell's pulsing activity, while a normal stills camera captured detailed images. But aligning the two sets of images proved fiddly and frustrating.

So the team took an off-the-shelf video camera to pieces and rebuilt it to perform both roles, simultaneously recording high-speed video and high-resolution stills.

Related Link
Temporal pixel multiplexing for simultaneous high-speed, high-resolution imaging Nature Methods

ScienceNOW: Have you ever noticed that the first gunslinger to draw his gun in a movie is invariably the one to get shot?

Nobel prize–winning physicist Niels Bohr did, once arranging mock duels to test the validity of this cinematic curiosity.

Following Bohr's example, researchers have now confirmed that people move faster if they are reacting to another person's movements than if they are taking the lead themselves.

Nature: A living cell can be thought of as a building of extremely peculiar architecture, in which the walls are formed by films just a few nanometers thick—the cell membranes.

The diversity and dynamics of membrane shapes are vital for the cell's physiology. One of the biggest challenges in cell biology and biophysics is therefore to understand the molecular mechanisms that enable cell membranes to bend easily and rapidly into highly curved, dynamic shapes. Reporting in the Journal of the American Chemical Society, Y. Yu and coworkers describe a promising synthetic model of membranes that can be used to assess experimentally the combined influence of lipids and proteins on membrane curvature.

Related link
Vesicle budding induced by a pore-forming peptide

Science: In the natural sciences, x-ray crystallography has clarified how the shapes of proteins and related complexes relate to their cellular function, and x-ray scattering has elucidated the structure and dynamics, mechanical properties, and intermolecular interactions of countless materials.

In Science, H. Cui and coworkers report a new twist in the application of x-ray scattering, where synchrotron x-ray irradiation, in addition to its usual role in probing structure, acts as a reversible switch for self-assembly from a disordered to an ordered state of bundled filaments.

Related link
Spontaneous and x-ray–triggered crystallization at long range in self-assembling filament networks

Nature: The surprising discovery of methane in Mars's atmosphere could be a sign of life there. Researchers are now working out how to find its source, reports Nature's Katharine Sanderson.

Science: If there's one thing you can be sure about with particle accelerators, it's that they're expensive to build. The €3 billion Large Hadron Collider at CERN is the most extreme example. But even at the other end of the scale, a hospital that wants an accelerator for proton beam therapy for cancer patients will likely have to fork out more than $100 million, and neither of the two most common existing technologies—cyclotrons and synchrotrons—is well-suited to the task. Now a handful of accelerator physicists are experimenting with a new type of machine—a cross between a cyclotron and a synchrotron—that avoids many of the shortcomings of both and is simpler and cheaper to build.

guardian.co.uk: From Leonardo da Vinci to Le Corbusier, the golden ratio is believed to have guided artists and architects over the centuries.

Leonardo is thought to have used the golden ratio, a geometric proportion regarded as the key to creating aesthetically pleasing art, when painting the Mona Lisa.

Now a US academic believes he has discovered the reason why it pleases the eye.

According to Adrian Bejan, professor of mechanical engineering at Duke University in Durham, North Carolina, the human eye is capable of interpreting an image featuring the golden ratio faster than any other.

Physics Today: Researchers at Rice University and Baylor College of Medicine (BCM) have created a single nanoparticle that can be tracked in real time with MRI as it homes in on cancer cells, tags them with a fluorescent dye, and kills them with heat.

The all-in-one particle is one of the first examples from a growing field called "theranostics" that develops technologies physicians can use to diagnose and treat diseases in a single procedure.

The research is available online in the journal Advanced Functional Materials. Tests so far involve laboratory cell cultures, but the researchers said MRI tracking will be particularly advantageous as they move toward tests in animals and people.

"Some of the most essential questions in nanomedicine today are about biodistribution—where particles go inside the body and how they get there," said study co-author Naomi Halas. "Noninvasive tests for biodistribution will be enormously useful on the path to FDA approval, and this technique—adding MRI functionality to the particle you're testing and using for therapy—is a very promising way of doing this."

The all-in-one particles are based on nanoshells—particles Halas invented in the 1990s that are currently in human clinical trials for cancer treatment. Nanoshells harvest laser light that would normally pass harmlessly through the body and convert it into tumor-killing heat.

In designing the new particle, Halas partnered with Amit Joshi, assistant professor in BCM's Division of Molecular Imaging, to modify nanoshells by adding a fluorescent dye that glows when struck by near-infrared (NIR) light. NIR light is invisible and harmless, so NIR imaging could provide doctors with a means of diagnosing diseases without surgery.

In studying ways to attach the dye, Halas's graduate student, Rizia Bardhan, found that dye molecules emitted 40–50 times more light if a tiny gap was left between them and the surface of the nanoshell. The gap was just a few nanometers wide, but rather than waste the space, Bardhan inserted a layer of iron oxide that would be detectable with MRI. The researchers also attached an antibody that lets the particles bind to the surface of breast and ovarian cancer cells.

In the lab, the team tracked the fluorescent particles and confirmed that they targeted cancer cells and destroyed them with heat. Joshi said the next step will be to destroy whole tumors in live animals. He estimates that testing in humans is at least two years away, but the ultimate goal is a system where a patient gets a shot containing nanoparticles with antibodies that are tailored for the patient's cancer. Using NIR imaging, MRI, or a combination of the two, doctors would observe the particles' progress through the body, identify areas where tumors exist, and then kill them with heat.

"This particle provides four options—two for imaging and two for therapy," Joshi said. "We envision this as a platform technology that will present practitioners with a choice of options for directed treatment."

Eventually, Joshi said, he hopes to develop specific versions of the particles that can attack cancer at different stages, particularly early-stage cancer, which is difficult to diagnose and treat with current technology. The researchers also expect to use different antibody labels to target specific forms of the disease. Halas said the team has been careful to choose components that either are already approved for medical use or are already in clinical trials.

"What's nice is that every single component of this has been approved or is on a path toward FDA approval," Halas said. "We're putting together components that all have good, proven track records."

Various: A new study from the National Cancer Institute projects 29 000 excess cancers from the 72 million CT scans that Americans got in 2007 alone. Nearly 15 000 of those cancers could be fatal.

It has been known for sometime that doctors had been overprescribing the number of CT scans for their patients, but this is one of the first comprehensive studies in the US that has quantified the risk using actual medical data.

Richard Knox at NPR reports that one of the reasons for the large number of scans is because doctors have been seduced by the high-resolution images CT scans produce, and have not considered the risk to the patient of using high-intensity x rays.

"Physicians [and their patients] cannot be complacent about the hazards of radiation or we risk creating a public health time bomb," said Rita Redberg, editor of Archives of Internal Medicine, which published the paper.

Children, younger adults and women are especially susceptible. Two-thirds of the excess cancers will occur in women, the NCI researchers say.

Projected Future Cancers Possibly Related To CT Scans In U.S.

The bars in the chart above indicate the projected average number of future cancers for each age range (95% uncertainty limits) that could be related to 2007 CT scans performed in the US, according to age at exposure. The lower and upper values represent the possible margin of error from the mean estimate.

"Although a guiding principle in medicine is to ensure that the benefit of a procedure or therapy outweighs the risk, the explosion of CT scans in the past decade has outpaced evidence of their benefit," said Redberg.

Related Links
Projected cancer risks from computed tomographic scans performed in the United States in 2007
Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer
Radiation from CT scans may raise cancer risk NPR
CT scans may pose higher risk of cancer than first thought The Daily Telegraph
Overuse of CT scans will lead to new cancer deaths, a study shows The Los Angeles Times

Science: Conventional solar technologies produce electricity, but most transportation fuel comes from oil. A new class of solar chemical reactors aims to make liquid fuels from air, water, and sunshine.

Nature News: Giorgio Riccobene, a particle physicist at the Southern Laboratories of the Italian National Institute for Nuclear Physics (INFN) in Catania, was hoping to show that hydrophones could be used to detect subatomic particles called neutrinos that had come from deep space.

Giovanni Pavan, a marine biologist from the University of Pavia in Northern Italy, was there to help Riccobene deal with background noise in the recordings.

But what Riccobene and Pavan discovered as they analyzed data from a series of hydrophones placed 28 kilometers off shore was the sound clicks of sperm whales, more whales in fact than biologists believed to exist in the area (see also powerpoint presentation 7.9 Mb).

The Economist: Airlines could take a more naturalistic approach to cutting jet-fuel use, and it would not require them to buy new aircraft.

The answer, says Ilan Kroo and colleagues at Stanford University, lies with birds. Since 1914, scientists have known that birds flying in formation—a V-shape, echelon, or otherwise—expend less energy.

Photo credit: John Avise, University of California, Irvine

The air flowing over a bird’s wings curls upwards behind the wingtips, a phenomenon known as upwash. Other birds flying in the upwash experience reduced drag, and spend less energy propelling themselves.

When applied to aircraft, the principles are not substantially different.

Kroo and his team modeled what would happen if three passenger jets departing from Los Angeles, San Francisco, and Las Vegas, and all traveling to London, were to rendezvous over Utah and assume an inverted V-formation.

They found that the aircraft consumed as much as 15% less fuel. Nitrogen-oxide emissions during the cruising portions of the flight fell by around a quarter.

Wired.com: Blue whales, the largest animals on Earth, are singing in ever-deeper voices every year. Among the suggested explanations are ocean noise pollution, changing population dynamics, and new mating strategies. But none of them is entirely convincing.

"We don't have the answer. We just have a lot of recordings," said Mark McDonald, president of Whale Acoustics, a company that specializes in the sonic monitoring of cetaceans.

McDonald and his collaborators first noticed the change eight years ago, when they kept needing to recalibrate the automated song detectors used to track blue whales off the California coast.

After collecting thousands of recordings taken over the last 40 years, he and his colleagues discovered that the songs' tonal frequency is falling every year by a few fractions of a hertz.

Science News: Want to make a planet that can sustain carbon-based life? Don't park it in orbit around a sunlike star.

"For the long term, the sun may not be the best star," says Edward Guinan of Villanova University in Pennsylvania, coauthor of a paper reporting a new model about the suitability of planets for life. Smaller, cooler stars called orange dwarf stars might be the most hospitable, he says.

NPR: John Dabiri, bioengineer at Caltech, has developed new techniques for studying the motion of aquatic animals. In a recent study in the journal Nature, Dabiri and Kakani Katija explain how swimming animals contribute to ocean mixing—the process that distributes heat, nutrients and gasses throughout the sea.

Related Link
A viscosity-enhanced mechanism for biogenic ocean mixing

guardian.co.uk: Tyrannosaurus rex was an athletic, warm-blooded animal that jogged rather than lumbered around its territory, according to a new study.

Researchers led by Herman Pontzer at Washington University in St Louis examined the anatomical details of 14 dinosaurs of different sizes to work out how much energy the animals might have needed to move around.

He found that, for dinosaurs weighing from a few kilograms to tons, the power their muscles needed was far too high for the animals to have been cold-blooded.

Related Link
Biomechanics of running indicates endothermy in bipedal dinosaurs

Wired.com: A cell in the eye may be worth two in the beak, at least when it comes to a migratory bird's magnetic compass.

In European robins (right image), a visual center in the brain and light-sensing cells in the eye—not magnetic sensing cells in the beak—allow the songbirds to sense which direction is north and migrate correctly, a new study finds. The study published in Nature, may improve conservation efforts for migratory birds.

Related Link
Visual but not trigeminal mediation of magnetic compass information in a migratory bird

The Daily Telegraph: The mantis shrimps, found on the Great Barrier Reef in Australia, have the most complex vision systems known to science, researchers at Bristol University have found.

The shrimps can see in 12 colors—humans see in only three—and can distinguish between different forms of light to give a sophisticated and vivid 3D image.

Related Update
A mantis shrimp's extraordinary eyes

Related Link
A biological quarter-wave retarder with excellent achromaticity in the visible wavelength region Nature Photonics

NYTimes.com: Two cases involving CT scans are under scrutiny in California—one involving a large, well-known Los Angeles hospital, the other a tiny hospital in the northern part of the state—underscoring the risks that powerful CT scans pose when used incorrectly.

Raven Knickerbocker, then an X-ray technologist at Mad River Community Hospital in Arcata, activated a CT scan 151 times on the same area of the head of 2 ½-year-old Jacoby Roth, investigators concluded.

A week ago, Cedars-Sinai Medical Center in Los Angeles disclosed that it had mistakenly administered up to eight times the normal radiation dose to 206 possible stroke victims over an 18-month period during a procedure intended to get clearer images of the brain.

Although CT scans are useful in determining internal injuries, there are major risks associated to patients because of the intensity of the X-rays used in the device, either through human error, or through too frequent exposure to X-rays.

In 2000-2001, CT scans constituted 7% of all radiologic examinations, but contributed 47% of the total collective dose from medical X-ray examinations.

Nature News: A new generation of light sources—the newly completed Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory in Menlo Park, California; one under construction in Japan; and the European X-Ray Free-Electron Laser (XFEL) being built at DESY in Germany—are getting set not only to put atoms and molecules under the spotlight, but also to illuminate their dynamics.

The devices, called x-ray free-electron lasers, produce flashes of x-ray light with angstrom-level wavelengths—small and coherent enough to image individual atoms. The flashes are also more intense than any created before—stuffed with enough photons to create and study extreme states of matter such as plasma.

But perhaps most importantly, the bursts of light are short—just hundreds of femtoseconds long, the time it takes for light to cross a human hair. Pulses as brief as this can record functions, not just forms: the folding of a protein, the action of a catalyst, the splitting of a chemical bond.

Physics Today: The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Chemistry for 2009 jointly to

Venkatraman Ramakrishnan, MRC Laboratory of Molecular Biology, Cambridge,United Kingdom
Thomas A. Steitz, Yale University, New Haven, CT, USA
Ada E. Yonath, Weizmann Institute of Science, Rehovot, Israel

"for studies of the structure and function of the ribosome."

Inside every cell in all organisms, there are DNA molecules. They contain the blueprints for how a human being, a plant, or a bacterium looks and functions.

The DNA is transformed into living matter through the work of ribosomes. Based upon the information in DNA, ribosomes make the chemistry of life: proteins, such as oxygen-transporting hemoglobin, antibodies of the immune system, hormones such as insulin, the collagen of the skin, or enzymes that break down sugar.

There are tens of thousands of proteins in the body and they all have different forms and functions.

Ramakrishnan, Steitz, and Yonath discovered what the ribosome looks like and how it functions at the atomic level.

All three used X-ray crystallography to map the position for each and every one of the hundreds of thousands of atoms that make up the ribosome and created 3D models that show how different antibiotics bind to the ribosome. X-ray crystallography is a fundamental research tool in biophysics and chemistry, and has resulted in a number of Nobel Prizes.

"Today's award is one of the great stories in biophysics," says Jason Bardi, a spokesperson for the American Institute of Physics (which publishes Physics Today). "People worked for years to get these structures, and for a long time, many in the field doubted whether it could even be done."

The ribosome is a massive protein, weighing in at 2.5 million atomic mass units (amu) and has a complicated structure.

Ribosomes are so big that they can often be spotted under electron microscopes but attempts to look at their structures using diffracted light of much shorter X-wavelengths proved to be challenging.

When the hi-resolution images of ribosomes came out a decade ago by the three laureates, it was held as a significant breakthrough. "Frankly I was stunned," says Bardi. "The ribosomal structure most familiar to me previous to that was the one that adorned my "GENES IV" textbook in graduate school. It was a big purple blob—a molecular Barney. Now suddenly, I could see a thousand interwoven protein helices and finger-like sheets and an impossibly complicated tangle of RNA. It was a truly stunning image."

Paul Guinnessy

Related Physics Today Resources
A three-dimensional x-ray image of a single pair of human chromosomes, Charles Day, February 2009
Time-resolved macromolecular crystallography, Eric A. Galburt and Barry L. Stoddard, July 2001
Nobel Prize in Chemistry to Hauptman and Karle, Bruce Schechter, December 1985
Aaron Klug wins Nobel Prize in Chemistry, Bertram M. Schwarzschild, January 1983

Related Resources
Protein factory reveals Its secrets Chemical & Engineering News, February 2007
Venkatraman Ramakrishnan
Thomas A. Steitz
Ada E. Yonath

Related News Stories
Ribosome map makers win chemistry Nobel NPR
Cambridge chemist wins Nobel prize for showing how proteins are made in cells The Guardian
Three share Nobel Prize in Chemistry Associated Press
Three win Nobel for ribosome research New York Times

NYTimes.com: Researchers have discovered that the topography of a desert locust’s wings and the way they twist when flapping are important for the insect’s efficiency as a flier. Compared with flat, stiff wings, they produce about 30 percent more lift for the same effort.

IEEE Spectrum: The human eye is a perceptual powerhouse. It can see millions of colors, adjust easily to shifting light conditions, and transmit information to the brain at a rate exceeding that of a high-speed Internet connection.

But why stop there?

In the Terminator movies, Arnold Schwarzenegger's character sees the world with data superimposed on his visual field--virtual captions that enhance the cyborg's scan of a scene. In Rainbows End by the science fiction author Vernor Vinge, characters rely on electronic contact lenses, rather than smartphones or brain implants, for seamless access to information that appears right before their eyes.

"These visions might seem far-fetched, but a contact lens with simple built-in electronics is already within reach," says Babak A. Parviz.

"In fact, my s