Proceedings of the National Academy of Sciences

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

Science, November 20
A fascinating study brought new insight into the disappearance of North America’s prehistoric megafauna, via a study of a fungus present in their mega-dung. The fungus releases a spore that is preserved in sediment samples, which researchers can analyze to determine how prevalent the great beasts were throughout history. The new analysis suggests that megafauna like mastodons, mammoths, and sabre-toothed tigers began a slow decline around 15,000 years ago and vanished completely about 1,000 years later. This suggests that their extinction was not a result of an asteroid or comet that is thought to have exploded over North America much later. It also takes the blame off the Clovis people, who were thought to be North America’s first settlers, but who didn’t establish themselves until about 13,300 years ago. Some researchers have suggested that the Clovis people hunted mammoths and the like into extinction. While the new study makes a good argument, it’s unlikely to persuade all proponents of alternate theories–expect rebuttals to follow. Another study revealed the results of a four-year effort to map the genome of corn. The task turned out to be surprisingly complex, as the corn genome has 12,000 more genes than the human genome, but the resulting data has already helped scientists understand how maize was domesticated, and should help agricultural researchers increase the efficiency of corn crops.

Journal of the American Medical Association, November18
Upper-crust ancient Egyptians weren’t so different from modern Americans in one way: a new study that X-rayed 20 Egyptian mummies found signs of clogged arteries and heart disease in 16 of them. Since only the Egyptian elite were mummified, it’s impossible to say if cardiovascular problems were widespread in ancient Egypt. But the researchers note that the elite often dined on rich dishes such as beef, mutton, and cakes with honey and butter, and suggest that this fatty diet may have contributed to heart disease among the nobility.

Nature, November 19
In another warning bell regarding global warming, a study found that the world’s oceans are absorbing less globe-warming carbon dioxide than they used to. Until about the 1980s, researchers say, the absorption rate kept pace with increasing greenhouse gas emissions. But since then the intake rate has slowed, due to a gradual change in the oceans’ chemistry. The increased load of CO2 in the seawater is changing the pH balance of the oceans and making them more acidic, which then limits the amount of CO2 they can sop up. The results are troubling, because they indicate that even more greenhouse gases will remain in the atmosphere.

Proceedings of the National Academy of Sciences

Journal of the American Medical Association, November 4
A new study of hospitalizations in California due to swine flu has highlighted a neglected risk factor: obesity. In the study group of patients whose weight was known, researchers found that 25 percent of the people were morbidly obese, although less than 5 percent of the U.S. population falls into that category. Researchers also found that 58 percent of these hospitalized patients were obese–in the population as a whole, about 34 percent of people are obese. The increased risks come partially from health problems associated with obesity, like heart disease, lung ailments, and diabetes. But physiological factors may also be to blame: The lungs of obese patients are squeezed by the abdomen pressing upward on the diaphragm.

Nature, November 5
A new astronomy study has solved a mystery that began brewing in 1680, when Britain’s first Astronomer Royal spotted a supernova in the constellation Cassiopeia. Supernova typically collapse into a super-dense object like a black hole or a neutron star, but for decades astronomers have looked for such an object at the center of the supernova remnant, to no avail. Now, a new examination suggests that there is indeed a baby neutron star there, but it escaped detection because it’s swaddled in an unusual atmosphere of carbon gas. Further studies of the 330-year-old star will give researchers insight into how such stars mature. Another study brings us from the macro to the micro, with an investigation into the evolution of bacteria. Researchers forced bacteria to evolve in constantly changing conditions, so that natural selection couldn’t produce microbes that were ideally suited to a single environment. Instead, researchers proved that the bacteria hedged their bets by evolving into a strain that could form several different shapes from the same genetic material. The will to survive: It’s an amazing thing.

Science, November 6
The biggest study from Science reveals a very promising treatment for the fatal, inherited brain disease that was made famous by the movie Lorenzo’s Oil. Adrenoleukodystrophy (ALD) is caused by a faulty gene that leads to the destruction of nerve fibers’ insulating sheaths; without that insulation, electrical signals can’t be transmitted. The progressive disease is usually diagnosed in young boys, who typically die before adulthood. In the new experimental treatment, researchers used a deactivated HIV virus to ferry a working gene into the stem cells found in the patients’ bone marrows. Since the virus integrates itself permanently into the DNA of the cells it enters, researchers hope the patients will keep the working genes for the rest of their lives. More than two years after the treatment, the patients show no sign of further deterioration, and are able to live relatively normal lives. While the boys will continue to be monitored for side effects, the study brings fresh hope not just to ALD sufferers, but also to those who believe that gene therapy holds tremendous medical promise, despite earlier setbacks.

Current Biology, November 3
When Charles Darwin and the crew of the HMS Beagle arrived at the remote Falkland Islands, 300 miles from the tip of Argentina, they wondered how the islands came to be populated with the strange Falkland wolves. The small wolves were the only mammals present on the islands, and one theory of their origin posited that they were descended from dogs brought over by Native Americans. Now a new genetic study of four museum specimens (sadly, the wolves have since gone extinct) has proven that theory wrong. The study showed that the wolves shared a common ancestor at least 70,000 years ago, which suggests that the wolves arrived on the islands long before the first humans made it to the new world.

Nature Nanotechnology

Journal of the American Medical Association, October 28
The new generation of antipsychotic drugs may be of enormous benefit to patients’ mental health, but they may take a toll of their bodily health. A study of children and adolescents taking the drugs for the first time found that the young patients added 8 to 15 percent to their weight in less than 12 weeks, leading researchers to caution that the pills may put patients at risk of diabetes and heart disease. The study focused on young patients in order to examine the drugs’ effects on people who had never tried them before, but researchers believe they have the same metabolic effects on adults.

Proceedings of the National Academy of Sciences, October 27
Here’s a strange tale of animal behavior that could make for a lurid episode of the Sundance Channel’s Green Porno: Researchers have discovered that one species of jumping spider uses a bloody perfume to make itself irresistible to the opposite sex. According to the study (not yet available online), spiders that feast on blood-fattened mosquitoes just before they search for a mate have much more success than those that eat anything else, including mosquitoes that had been fed on sugar. Stepping from the insect to the mammalian world, another study examined the medical lessons that can be learned from naked mole rats, those ugly subterranean rodents with unusually long life spans. Researchers previously noted that mole rats never get cancer, and now they think they know why: The mole rats’ cells hate to be crowded and stop multiplying when they come into contact with each other. That means that the runaway cell divisions that produce cancerous tumors can’t take place.

Nature, October 29
Researchers have taken another step towards understanding the uncanny accuracy with which migratory birds navigate their annal routes: At least in the case of the European robin, they’re aided by amazing magneto-vision! Researchers knew that some birds can detect magnetic fields, but weren’t sure how the mechanism worked. Now, a new study has found that certain proteins in light-sensitive cells in a robin’s eyes convey the message to a visual processing area of its brain. The study also disproved the theory that it is iron-based cells in the birds’ beaks that did the trick. Moving on to a journey just a tad bit longer than that of a European robin, another study examined some gamma rays that traveled billions of light-years across the universe. The gamma rays were the result of a massive supernova that occurred 7.3 billion years ago, and they were detected by the Fermi Space Telescope. Astrophysicists realized they offered an excellent opportunity to settle some nagging questions about the nature of space-time: namely, is it smooth and continuous, as Einstein’s theory of general relativity assumed, or is it granular and sometimes lumpy, as predicted by quantum mechanics? If space-time is lumpy, then the gamma rays with the shortest wavelengths might get slowed down by inference from the tiny grains as they travel across the universe, while rays with longer wavelengths would speed on ahead. So researchers checked to see if the gamma rays detected by the Fermi Telescope arrived in a staggered procession–but they didn’t, instead they all arrived within nine-tenths of a second. Their conclusion: Space-time is smooth, and Einstein was right about the speed of light always being constant. Unless, of course, the grains of space-time are much smaller than we have ever dared imagine, and had a much tinier effect on the gamma rays. Got all that?

Nature

Journal of the American Medical Association, October 21
An article in JAMA kicked up a bit of fuss by questioning the effectiveness of widespread screening for prostate and breast cancer. The authors note that prostate cancer screenings can turn up very slow-growing cancers that don’t pose a real threat, and say that treating such cancers can actually cause more harm to patients than leaving them be. They note a similar trend with the mammographies that screen for breast cancer. While the authors don’t go so far as to recommend the cessation of screening programs, they do ask for a better discussion of benefits versus risks.

Science, October 23
Amphibian populations are crashing around the world, and experts say that the chytrid skin fungus is one of the major culprits–but until now, no one understood how the fungus was killing frogs and toads and other creatures. A new study cracked the case by showing that the fungus interferes with frogs’ ability to absorb nutrients through their porous skin. The electrolytes that frogs usually get from their watery environments play a crucial role in muscle and nerve function; when their levels plummet, the frogs’ hearts shut down. While the new findings don’t offer any immediate hope for ways to treat fungal infections in the wild, researchers are determined to gather all the information they can about this killer.

New England Journal of Medicine, October 20
One of the most confounding stories in medicine over the past weeks has been the frustrating tale of the HIV vaccine that either showed the first real promise in preventing HIV infection, or was yet another dud–depending on how you look at it. In late September, researchers announced the results of a large clinical trial of the vaccine in Thailand, saying that people who received the vaccine were 31 percent less likely to get HIV. While the vaccine’s protection seemed limited, there was much rejoicing. But within weeks, other AIDS researchers declared that a different analysis of the trial’s results made it appear that the vaccine’s benefits were a fluke. The two sides have been hashing it out this week at the AIDS Vaccine Conference, drawing fresh evidence from the full trial results that were published in a study in NEJM.

PLoS ONE, October 21
Finally, on a lighter note: A new study has determined that the testosterone levels of male John McCain supporters dropped dramatically on Election Night 2008, when Barack Obama soundly beat their candidate. Men who supported Obama’s candidacy showed no corresponding boost in testosterone levels, and women’s hormone levels also stayed steady. The results were based on saliva samples taken at regular intervals on election night, and a surveys also revealed that the McCain supporters felt submissive, controlled, and unhappy. Researchers say the findings are proof that politics can affect men in the same way that physical contests for dominance do.

Current Biology, October 13
In Central America and Mexico, entomologists have discovered the first known spider that passes on plump and meaty ants, and instead feasts on leafy greens. The spider maintains the hunting methods of its arachnid relations, the study explains, it just turns them on a different target–it stakes out a position on an Acacia tree, darts past the ants that protect the protein-rich leaf tips, and then makes off with its veggie delight.

Journal of the American Medical Association, October 14
A collection of studies examined who’s getting the sickest from the swine flu, and how their illnesses progress. The studies found that unlike seasonal flu which causes the most severe symptoms in the young, old, and infirm, the H1N1 swine flu virus is likely to cause serious illness in relatively healthy adolescents and young adults. Almost all of the patients who have gotten critically ill were sick for only a couple of days before they developed serious symptoms like acute respiratory failure that required treatment with breathing machines. The study also looked at mortality rates among those patients who became critically ill, and found that they ranged from 14 percent in Canada to 41 percent in Mexico. The authors stressed that these studies focused on the sickest of the sick, and noted that the overall mortality rate for swine flu is so far about equivalent to that of seasonal flu. Still their take home message was simple: Avoid trouble, and get the vaccine.

Nature, October 15
Nature was packed with interesting developments this week. In one study, researchers described a new process that will allow them to measure the activity of individual neurons that deal with the understanding of location. Because a mouse running through a real maze would dislodge the delicate monitoring implant, the researchers created a type of treadmill with a fixed metal helmet. To get the mouse moving, they surrounded the treadmill with “a mini-IMAX theater,” on which they projected views of a twisting corridor drawn from the video game Quake. In another biology study, researchers examined how fruit flies decide who to mate with, and got a surprise. The scientists had assumed that some mix of pheromones signaled to potential mates, but instead they found that the total lack of pheromones was the most powerful aphrodiasic. A female that lacked all pheromones attracted males that weren’t even of her species, and a male without pheromones attracted other males. This suggests that pheromones don’t only say come-hither, they also broadcast a keep-away message.

Science, October 16
The far-out news this week comes from the Interstellar Boundary Explorer (IBEX), a NASA probe that is tasked with mapping the border between our solar system and interstellar space. A new study, one of several that have emerged from a batch of new data, found a narrow “ribbon” of neutral atoms at the edge of the heliosphere, the bubble of space defined by the solar wind that is continuously blasted outward from the sun. The ribbon of atoms was completely unexpected, and researchers don’t yet know how to explain it. It’s possible that the magnetic field produced by the interstellar medium is exerting pressure on the particles, causing them to bunch together just inside the heliosphere.

Proceedings of the National Academy of Sciences

Nature, October 8
The biggest news in Nature was really, really large: Astronomers working with the Spitzer Space Telescope found a ghostly new ring around Saturn, and say the entire volume of the huge, diffuse ring could hold 1 billion Earths. The ring was never spotted before because it’s far out from the planet, and it’s comprised of very few particles–but it’s there. Researchers say it’s made of debris ejected from Saturn’s outlying moon Phoebe during comet or asteroid impacts, and the study also notes that its particles probably account for the strange coloration of another nearby moon, Iapetus. That moon is darker on one side, as if it has been catching particles on one side “like bugs on a windshield.” In another report, genetics pioneer Craig Venter and friends penned an article about how to improve the direct-to-consumer genetics tests that have popped up recently. The scientists compared test results from two direct-to-consumer companies, 23andMe and Navigenics, and found they diverged widely on their assessment of health risks. Venter’s team argues that the companies should agree on which genetic markers to use for various diseases, and also says they should be more forthcoming about the limitations of such tests.

Science, October 9
In a surprising turn of events, researchers have linked the baffling ailment called chronic fatigue syndrome to a retrovirus. For years, people diagnosed with the syndrome have suffered not just from debilitating fatigue and an assortment of aches and pains, but also from suggestions that they’re malingering, and that whatever is wrong with them is all in their head. The new study didn’t outright prove that the retrovirus causes the syndrome, but since the virus was found in 67 percent of patients with the syndrome and only 4 percent of healthy people, it does prove that there’s a biological component of the ailment.

The Lancet, October 9
To conclude, a bit of happy news. A study of an experimental cholera vaccine had success in protecting Indian children from the infectious disease, giving world health officials fresh hope that they’ll soon be a way to combat cholera, which kills 120,000 people every year worldwide. The massive trial found that the vaccine was safe, and 67 percent effective in preventing infections. While scientists would obviously prefer a vaccine that’s 100 percent effective, the new drug can still be an important tool.

Science

Proceedings of the National Academy of Sciences, September 29
The world may still be in the grip of a global recession, but that may not be entirely a bad thing: Researchers found that when the economy takes a turn for the worse, public health actually improves. Mortality rates fell during the Great Depression, the study found, possibly because people couldn’t afford to smoke and drink as much, and because the unemployed have more time to sleep and less chance of dying in industrial or traffic accidents. In some lighter and bubblier news, another study probed the enduring mystery of why champagne bubbles are so essential. They don’t just provide a fizzy feeling on the tongue, researchers found–they also carry aromatic chemical compounds up through the liquid and release them into the air above the glass. The subtle fragrance enhances the overall flavor, scientists said as they happily waved their glasses for a refill.

PLoS ONE, September 30
This study got wide attention in large part because it dealt with a celebrity dinosaur: Sue, the Tyrannosaurus rex on exhibit in Chicago’s Field Museum. Paleontologists re-examined the round holes in the dinosaur’s mandible that had previously been considered bite marks, and argued that the holes were actually caused by a lowly parasite commonly found in pigeons. The researchers argue that the throat infection first formed lesions and then wore the bone away in spots. The resulting inflammation choked off the dino’s esophagus, they say, eventually killing the mighty beast. It’s an interesting story, but the researchers haven’t convinced everyone.

Proceedings of the Royal Society B, September 30
Oddly enough, the next study also involves a controversy over the cause of death of a long-deceased somebody–this time, an Egyptian noblewoman named Irtyersenu who was mummified around 600 BC. In 1825, Irtyersenu became the subject of the first scientific autopsy of a mummy. The doctor found an ovarian tumor (the mummy was preserved with its organs intact) and pronounced it the cause of death, but the new study refutes that claim. The tumor was benign, researchers say, and it was actually tuberculosis that did in Irtyersenu.

Nature, September 29
A study on earthquakes was eerily well timed, as it immediately followed a tsunami-triggering quake in the South Pacific, and an even more destructive quake in Indonesia. The researchers looked back over the well-kept seismic records from the San Andreas fault in California, and found evidence that the 9.3 magnitude Sumatra earthquake of 2004 weakened the San Andreas fault thousands of miles away, making it more prone to tremors. The researchers hope that the work could one day help experts predict earthquakes, but for now, it’s just a hope.

Science

Nature Neuroscience, October
Two papers in this journal upended expectations of who can learn, and what they can learn. In the first study, researchers found that coma patients in a completely unresponsive, vegetative state are nonetheless capable of the most basic kind of learning: Pavlovian conditioning. These patients learned to associate a noise with an unpleasant puff of air to their eye, and began blinking or twitching as soon as they heard the noise. The findings suggest that these patients may have a rudimentary level of consciousness that isn’t detected in other tests. In the second study, researchers trained paralyzed rats to walk again using a combination of treadmill exercise, drugs, and direct electrical stimulation of their nerves. Although the rats’ damaged spinal cords couldn’t convey a message from their brains to their legs, the spinal circuits could be coaxed into sending the messages to the legs, resulting in movement that was almost indistinguishable from normal walking.

Proceedings of the National Academy of Sciences, September 22
This was pretty clever. Researchers had been stymied in their attempts to determine whether drinking alcohol at a young age causes people to take more risks later in life; the evidence seemed to suggest it, but researchers couldn’t rule out the possibility that it was people’s risk-prone personalities that caused them to drink in the first place. So in this study, researchers took two groups of genetically identical adolescent rats, and fed one group alcoholic jello shots! Then they taught both groups of rats to gamble, with sugar pellets as the jackpots, and found that the rats that had boozy diets were more likely to take big risks. Like we said–pretty clever.

Nature, September 24
Nature’s cover story didn’t get much attention, probably because population genetics isn’t as fun to read about as boozing rats. The study conducted the largest ever DNA survey of people living on the Indian subcontinent, and found that its population descends from two distinct genetic groups. One lineage, which has genetic similarities to people from the Middle East and Europe, while the second lineage was similar only to indigenous people in the remote Andaman Islands in the Bay of Bengal. Another report looked ahead instead of backward, and issued guidelines for what humans should do in order to keep our planet’s environment from crashing and burning, which would inevitably have serious implications for human life. In what they called a “user’s manual” for Earth, researchers listed nine limits that we should live within, including the amount of carbon dioxide in the air, the amount of nitrogen pollution in our waters, etc. One troubling aspect: We’ve already surpassed three of the limits.

Proceedings of the National Academy of Sciences

PLoS ONE, September 16
In a new report in this open access journal, researchers describe a cell phone app designed to help both professional scientists and citizen scientists. The program allows people to collect data on a subject like the changing habitat of a rare species by recording notes, photos, or videos on their smart phones; the program would then use the phones’ GPS system to determine the user’s location and to plot the data on a map. It’s a nifty research method that is bound to become more prevalent as smart phones find their way into more people’s hands.

Nature, September 17
It was the biggest science news of the week: Researchers used gene therapy to cure color blindness in two squirrel monkeys, suggesting that treatments for blindness in humans may be down the road. In the study, researchers say they were delighted and surprised to find that inserting a gene into the monkeys’ eyes corrected their vision, even though the adult monkeys’ brains were fully formed and couldn’t “rewire” themselves in response to the new gene. The findings suggest that the human brain is considerably more adaptable than we thought.

New England Journal of Medicine, September 16
Over the past decades Americans have been sucking up sugary drinks at a furious pace, and doctors say it’s no coincidence that we now have an obesity epidemic on our hands. To encourage consumers to make healthier choices, seven experts in nutrition, public health, and economics published a paper calling for a tax on soda and other sugar-sweetened beverages. This idea is catching on with policymakers looking for new revenue that could be used for government health care programs, but the beverage industry is, unsurprisingly, furious to have its products singled out as a major cause of obesity.

Science, September 18
Researchers have found the fossil of what looks like a miniature Tyrannosaurus rex, a toothy little man-sized beast that has ravaged previous theories of how the T. rex evolved. In a new study researchers describe Raptorex kriegsteini as a 9-foot-long, 150-pound creature with powerful back legs, runty forelegs, a whip-like tail, and a disproportionately large head. The fossil surprised paleontologists because it was previously believed that the T. rex evolved these distinct features as a consequence of its huge body size. The finding of Raptorex, which lived 35 million years before its colossal descendant, suggests that in fact the predator’s body type was set early on, and that the dinosaur then just scaled up over time.

Nature Genetics, September
Three new genes have been linked to a person’s risk of developing Alzheimer’s, according to two separate research groups. Two of the genes play a part in clearing away the toxic amyloid proteins that form plaques in the brains of Alzheimer’s patients. While the research doesn’t have any immediate applications for treating Alzheimer’s, every bit of information helps as scientists seek to understand the origins of the baffling disease.

Nature, September 10
Researchers have determined how an infectious deer disease is spreading so rapidly through herds across North America. The brain infection, which leads to fatal chronic wasting disease, is spread by infectious agents called prions that appear in the feces of infected deer up to a year before they become ill, and remain in the soil until other deer ingest them while grazing. The study’s results were surprising because the prions that give rise to the related mad cow disease are not shed by infected animals, but instead accumulate in the brain and spinal cord. Moving from the animal to the plant kingdom, scientists also decoded the genome of the potato fungus responsible for the Irish potato famine in the 1800s, and which still troubles farmers around the world. The study found that the fungus has an usually large genome, allowing the pathogen to adapt to new conditions and target new plant strains that are supposed to be resistant to the blight.

Science, September 11
The Arctic is changing so quickly as a result of global warming that iconic animals like narwhales, walruses, seals, and polar bears are facing serious threats; some of these species could even go extinct before the end of the 21st century, a new report warns. The comprehensive study looked at ecological damage across polar ecosystems, and found that loss of sea ice, changing patterns of plant growth, and encroaching invasive species are making it harder and harder for native animals to survive. But maybe our extremely efficient brains will figure out a way out of this mess. Another study re-examined an old model of brain function that assumed that it takes a lot of energy for a brain cell to send out an electrical pulse–i.e., a message. Researchers realized the model was based on studies conducted in squid, which have conveniently large neurons that are easy to work on, and decided it would probably be a good idea to check the energy efficiency of mammal brain cells. Turns out, a rat neuron uses only a third as much energy as a squid neuron, which means our human brains are probably equally efficient.

Proceedings of the National Academy of Sciences, September 1
In the days after the devastating May 2008 earthquake in China’s Sichuan province, some researchers set out to determine the disaster’s immediate impact on the brains of healthy survivors. Using MRI scans, the researchers found functional changes in the survivors’ brains, namely increased activity in the regions involved in emotions and memory, but decreased connectivity between other brain regions. The study suggests that traumatized brains may be both overloaded and uncoordinated. This week also brought news of modest progress in the effort to cure type 1 diabetes, sometimes called juvenile diabetes. Harvard Stem Cell Institute co-director Doug Melton (whose two children are diabetic) published a study showing that diabetics’ own skin cells can be transformed into insulin-producing pancreatic cells. The cells haven’t yet been declared safe to transplant into human patients, and even if they were the nature of diabetes, an autoimmune disorder, means that they would be destroyed by the patient’s own immune system. But the achievement means that researchers can put both diabetics’ pancreatic cells and their immune cells together in the lab, to search for what triggers the disease.

Biology Letters, advance online publication September 2
Cotton-top tamarin monkeys were treated like royalty in this latest experiment: a professional cellist composed music that was specially designed to speak to their little monkey souls. The study found that the monkeys responded emotionally to the cello music composed for them, which was loosely based on the sounds tamarins make in the wild. Music based on contented monkey calls made the listeners calmer and more social, while the tunes based on distressed monkey noises made them jumpy and agitated. They didn’t respond at all to human music, except, oddly, to Metallica. They liked it.

Nature, September 3
This week’s Nature brought us a meditation on tipping points, new insight into a neighboring galaxy, and some freakin’ cool lasers. In the tipping point study, researchers looked across disciplines, from biology to economics, for early warming signs that a system was approaching its tipping point. By looking for patterns that preceded collapsing ecosystems and collapsing financial markets, researchers hope they’ll be able to avert some future disasters. Another study mapped our galactic neighbor, the Andromeda galaxy, in unprecedented detail, and found evidence that it has been growing by devouring other stars and galaxies. This isn’t really surprising–astronomers had already theorized that galaxies grow through collisions and accretion–but it’s neat to see the process in action. Finally, the laser study suggests that blasting high-pressure gas with laser beams can produce rapid cooling, which could lead to a new type of refrigeration.

Science, September 4
The news from Science included a study with big implications for human health. Researchers have found two antibodies that provide new hope in the hunt for an HIV vaccine. The antibodies can neutralize many of the types of HIV that are in circulation worldwide; while the study stresses that the research is in very early stages, it could theoretically lead to a vaccine that encourages the body to produce these protective antibodies.

Proceedings of the National Academy of Sciences, August 25
In a study that probably provoked fierce debate in text messages, emails, and blogs simultaneously, researchers found that people who frequently multitask are actually bad at multitasking. The researchers expected multitaskers to be better than average at organizing information and switching between tasks quickly, but found just the opposite. Elsewhere in the journal, researchers examined the genome of honeybees and offered a partial explanation of colony collapse disorder. The study suggests that a variety of viruses are damaging the bees’ ability to make proteins that are needed to protect them from all the other slings and arrows of the world, like bacterial infections and food shortages. While this is an incremental step towards understanding what is destroying honeybee hives around the country, every little bit helps.

Nature, August 27
The most exciting thing in Nature this week was a fairly technical paper about a clever bit of genetic engineering, but it nonetheless received a good bit of media attention due to 1) the ethical implications of the work and 2) the cute pictures of baby monkeys that accompanied it. The study documented a new procedure in which the nucleus from one female monkey’s egg was removed and placed in an egg that had its nucleus stripped out. That recipient egg still contained a small bit of DNA in the form of mitochondrial DNA that resides in the cell’s cytoplasm, which means that the egg became a hybrid of two women’s genetic material. The eggs were then fertilized and succesfully produced those cute baby monkeys, who have the distinction of having three genetic parents. The medical rationale for this: Many inherited diseases can be carried in mitochondrial DNA, and this procedure could give women a chance to swap out their faulty genetic material and have healthy babies.

Science, August 28
Perhaps in homage to the final dog days of summer, Science published a nifty genetic study revealing the surprising simplicity behind the wide variation in dog coats. Just three genes determine whether a dog’s hair will be long or short, straight or curly, wiry or fuzzy. In the past year, researchers have also figured out the genes responsible for short-legged breeds like dachshunds and bald breeds like Mexican hairless dogs–but they haven’t yet found the gene that makes dogs want to destroy your slippers. Another study in the journal reported on the mysterious way in which sunspots impact the Earth’s climate. Even though years of intense sunspot activity only increase the amount of solar radiation reaching Earth by a tiny amount, researchers found that busy solar years can cause big changes in rainfall and wind patterns around the globe. The findings could help meteorologists predict weather patterns, the researchers say.

The Annals of Internal Medicine, August 18
What killed Mozart? Maybe strep throat. While the medical sleuths who came up with this hypothesis acknowledge that there’s no way to test it–Mozart’s body vanished into a common grave that was later dug up to make room for more–their analysis of medical records in 1790s Vienna make strep a likely cause. The study found that edema was a common cause of death, which can be a complication of a strep infection; this could explain the severe swelling reported in Mozart’s final illness

Science, August 21
One paper in Science may have received wide coverage partially because of the pretty pictures. Researchers found five new species of deep-sea worms that are thought to fling out luminescent green “bombs” when attacked by predators. The bombs don’t do any damage, but they do distract the predator for long enough for the worm to make its escape. Beyond the nifty visuals, the study is also a reminder of how little we know about life in the ocean depths. Another study published on Science’s Web site shows that even though we’re still trying to find out what organisms currently grace our planet, we’re not holding back from trying to create entirely new synthetic life. Genetics pioneer Craig Venter announced that his team successfully took the genome from one species of bacteria, transplanted it into yeast cells for tinkering, and then placed the genome in a different bacterial species. The new organism “booted up” and came to life, Venter reports.

Current Biology, August 20
It’s so satisfying when science confirms a commonly held belief. This week, researchers found that people who are told to walk a straight course through the forest or desert really do end up going in circles. The study found that people trying to navigate without the aid the sun, moon, a map, or any obvious and looming landscapes walked a looping path. When the test subjects were later shown the course they followed on a GPS mapper, they were shocked. In another paper, scientists determined that our two nostrils are rivals for our brain’s attention. When test subjects were rigged up with a device that simultaneously piped one scent (roses) to one nostril and another scent (magic markers) to the second, the subjects detected the two scents in an alternating pattern, instead of a single odor that was a combination of the two.

New England Journal of Medicine, August 20
Many drug addiction counselors endorse harm reduction policies for hard-core heroin addicts, which can include supplying clean needles or “safe injection rooms” where addicts can shoot up, on the principle that such moves can reduce diseases and criminal behavior associated with addiction. Now, a new study has tested out the next controversial step in harm reduction: providing “prescription heroin” to addicts in a clinical setting. The study found that addicts who were given heroin were more likely to stick with a treatment program than those given methadone, and also reduced their criminal activity outside the clinic.

Pediatrics, August issue
An 18-year-long study found that autistic children do not have more gastrointestinal problems than other children, refuting a notion that has gained some currency with families of autistic children. The researchers note that some parents have adjusted their autistic children’s diets in hopes of altering the children’s symptoms, and call for a halt to such practices. Autistic kids should not be put on dairy-free or gluten-free diets without a proper diagnosis of dairy or gluten intolerance, the researchers say, because such restrictive diets can cause nutritional deficiencies.

Nature, July 30
A nifty new study has determined that the oceans are not mixed simply by macro forces like winds and tides, but also by the motion of all the critters, big and small, that swim through the watery expanses. Videotaped experiments with jellyfish and fluorescent green dye reveal that every time a sea creature moves, it brings some of the ocean with it. Another article caught the collective media eye since it offers tantalizing clues to a new obesity treatment. Researchers figured out how to change ordinary skin cells into brown fat cells, which are sometimes called “good” fat cells for their turbocharged ability to burn calories and turn them into body heat. While plump little babies have ample brown fat reserves, adults have very little. But the new study suggests that in time, researchers could find a way to boost brown fat deposits in adults to help them burn off those extra pounds.

Science, July 31
Feeling both stressed out and stuck in a rut? New research suggests there’s a good reason for that: rats that were exposed to chronic stress in the lab made decisions based on habit, even when those habituated decisions no longer provided the maximum amount of food pellets and sugar water. Relaxed mice were able to adapt as the circumstances changed. But here’s one less reason to stress out: New calculations show that a killer comet is quite unlikely to smash into the Earth, annihilating all life. The researchers’ main objective in this study was to figure out where comets come from–it turns out many come from a region at the solar system’s edge called the inner Oort cloud. But their corollary finding that even the worst comet showers produce few Earth impacts seemed more interesting to anyone who remembers the movie Deep Impact.