• Out of Africa: Touted as a “landmark study,” new genetic research suggests that the first humans came from southern Africa. In the study, they found more genetic diversity in the southern part of the dark continent—an indicator of longevity. Experts had previously pinned eastern Africa as the starting line for the human race.
• An apple a day keeps the fruit fly alive: Researchers discovered that fruit fly lifespans increase by about 10 percent when they’re fed a daily bit of apple. And the benefits don’t stop there: The apple’s healthful antioxidants also helped the flies’ walking and climbing abilities. Scientists note that because this research agrees with past apple studies on other animals, it should encourage more apple eating by humans too.
• Want to know your risk of lung cancer? Look down. The nicotine levels in your toenail clippings give an accurate idea of future lung cancer risk, according to new research: The men with the highest nicotine levels (mostly smokers, but also some second-hand smokers) were more than three times as likely to develop lung cancer as those with the lowest levels.

(more…)

• We at DISCOVER have always loved the terrifying specter of zombie animals controlled by menacing wasps, worms, and barnacles. This week there’s a new terror on the loose: Four newly found fungi that grow stalks right through the head of zombie ants in the Brazilian rainforest.
• No glory for Glory: The NASA climate mission we covered last week—which was to study the interaction of the sun’s radiation, aerosols, and greenhouse gases in the atmosphere—ended in failure as it did not reach orbit in its launch attempt today.
• It’s not Mega Shark vs. Giant Octopus, but a paleontologist’s research suggests that the story of North American survival long ago may have been bison v. mammoth. Eric Scott says the influx of bison from Eurasia may have doomed the saber-tooth cat, mammoth, and other megafauna that couldn’t compete.
• (more…)

• While modeling plasma flows deep inside the sun, scientists may have found an explanation for why some sunspots cycles (like the most recent one) are weaker than others. “It’s the flow speed during the cycle before that seems to dictate the number of sunspots. Having a fast flow from the poles while a cycle is ramping up, followed by a slow flow during its decline, results in a very deep minimum.”
• Risky business: In defending President Obama’s vision for space exploration that relies upon commercial space companies, NASA administrator Charles Bolden says the country must “become unafraid of exploration. We need to become unafraid of risks.”
• Bad timing: Just as Apple unveils its new iPad—and Steve Jobs uses the opportunity to gloat about his company’s superiority in apps compared to Google’s Android system—Google had to take 21 apps off the Android Market because they were infected with malware.
• (more…)

• Shark seek: Tiger sharks and thresher sharks remember and zero in on specific places to hunt for food in an area that might be 30 miles across. That shows they might possess not only the ability to navigate by smell or by the Earth’s magnetic field, but also broader spatial memory for their home range.
• “If you eat by shoving your entire writhing body into your meals, your dinner companions are probably going to leave.” The hagfish, however, has no such concern for manners: It absorbs its nutrients right through its skin.
• We be jammin’: Satellite provider Thuraya Telecommunications and news channel Al Jazeera both report that sources in Libya are illegally trying to jam their signals, and traced the attempts to “a Libyan intelligence service facility south of Tripoli.”
• British researchers discover a way to use urine tests to screen for prostate cancer—and potentially double the accuracy of current methods.
• Numismatist power: Coin experts create interactive digital maps of coins through history and where they came from, putting a treasure trove of information at historians’ fingertips.
• Super honey from down under: A myrtle native to Australia produces honey packed with antibacterial compounds that can stymie even antibiotic-resistant microorganisms like MRSA.

Image: Wikimedia Commons

• Materials violence: NASA will use a million pounds of force to crush a 20-foot-tall aluminum-lithium rocket fuel tank outfitted with sensors (all in the name of science, of course). The idea is to test out how modern composite materials buckle under incredible pressure, in the hope of finding out where the weaknesses might be.
• Real-life forensic science is rarely as easy or glamorous as its TV counterpart. Actual blood spatter experts, for example, don’t operate with quite the ease of the title character in “Dexter.” But a new study proposes a way to use simple trigonometry to calculate not only the point of origin for blood but also the height above the ground, which previously couldn’t be determined.
• You knew this day would come: The United States has approved the first deepwater offshore drilling permit given out since the Deepwater Horizon disaster.
• As strong as metal and as moldable as plastic: Yale scientist Jan Schroers’ new super-alloys.
• Half of adult males may be carrying the human papillomavirus (HPV), according to a study in The Lancet. It often lingers quietly but is transmitted sexually and is the cause of most cervical cancers in women.
• “Strictly speaking, there should be no blue whales.” So begins DISCOVER blogger Carl Zimmer as he explores the curious question of why blue whales, with so many more cells than human beings and so many chances for those cells to go wrong, are not killed by cancer at an astounding rate.

Image: NASA

• Who needs a vomit comet? The Southwest Research Institute (SwRI) in Colorado reached a deal with Virgin Galactic to send some of its scientists up on SpaceShipTwo’s suborbital flights, allowing them to conducts tests in weightlessness.
• Fire ants may have originated in South America, but their home base for invading the world at large is right here in the United States. So says a new study of more than 2,000 fire ant colonies spread around the globe.
• Gone in a flash: About 150,000 Gmail users woke up to find their mailboxes wiped clean—messages, folders, and all. Google is racing to recover the lost correspondences. In the meantime, this is a reminder of two things. First, you should back up your email. And second, Google is really, really big. Those 150,000 people represent just .08 percent of Gmail users.
• (more…)

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

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

(more…)

Proceedings of the National Academy of Sciences, November 10
The week’s most sensational news came from a PNAS study which heralded the repair of damaged rabbit penises by rebuilding crucial erectile tissue. The researchers proved that they could engineer new corpora cavernosas, the column of tissue that engorges with blood during male arousal, and the male rabbits demonstrated that their new parts worked just fine by mating and fathering offspring. While the technique isn’t ready for humans yet, researchers have high hopes that they’ll soon be able to help men who need penile reconstructive surgery. Spammers presumably have high hopes that they’ll soon be able to fill your inbox with messages touting the rabbit penis cure.

Human Reproduction, November 10
Since we have two stories that related to male sexual health, we’ll get them both out of the way. Then we’ll move on, we swear. This second study raised yet more troubling questions about the plastic chemical bisphenol A (BPA) that is found in everything from baby bottles to canned food linings. The researchers tracked the sexual health of more than 600 Chinese factory workers exposed to high levels of BPA, and found the men were four times more likely to suffer from erectile dysfunction and seven times as likely to have difficulty with ejaculation than factory workers who weren’t exposed to the chemical. Previous animal research has linked BPA to a host of other health problems, including fertility problems, cancer, and diabetes; this U.S. government-funded study seems to strengthen the case for taking the chemical off the market.

(more…)

Proceedings of the National Academy of Sciences, November 3
Two studies in PNAS focused on the wildlife and landscape of East Africa. In the first, researchers looked back in history to Kenya’s infamous man-eating lions, which reportedly devoured 135 railroad laborers in 1898. The two lions were eventually shot, killed, stuffed, and shipped to Chicago’s Field Museum for display–which allowed researchers to analyze samples of the lions’ bones and fur. By comparing the isotopes present in the man-eating lions to those found in other lions, humans, wildebeest, and buffalo, the researchers could precisely determine the lions’ diet. The results brought the body count down considerably: The scientists estimate that one of the lions ate 24 people, while the other gobbled up 11. The second study looked ahead, and predicted that Mount Kilimanjaro, the highest peak in Africa, could lose its distinctive ice cap by 2022 due to global warming.

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.

(more…)

Nature Nanotechnology, October
The carbon nanotubes that hold such technological promise may be more dangerous to human health than we realized, according to a new study. Lab mice that inhaled nanotubes were found to have the tubes in the outer linings of their lungs–that’s the same place where inhaled asbestos fibers settle and cause the slow-growing cancer known as mesothelioma. The researchers stress that they didn’t find any evidence of cancer in the mice that inhaled nanotubes during the 14-week study, but suggest that longer studies should examine the question further.

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.

(more…)

Nature, October 22
The top news this week was that a fossilized primate which got extraordinary hype last spring, when a TV documentary declared it a direct ancestor to humans and a “missing link,” probably didn’t play a major role in the evolution of humans, after all. A new study punched holes in the earlier work, arguing that the 47-million-year-old primate was nowhere near monkeys, apes, and humans on the primate family tree, but was instead part of the lineage that led to lemurs. This corrective study is gratifying to many evolutionary biologists who felt that the “missing link” study hadn’t been properly vetted, and was promoted so heavily in order to raise an audience for the TV show. Nature also had two interesting neuroscience studies this week. In the first, the memory problems of sleep-deprived mice were corrected by reducing the levels of one particular enzyme in the mouse hippocampus, the brain region involved in memory and learning. The study appears to point the way toward drugs for sleep-deprived humans, The second brain-related study identified, for the first time, a small group of neurons that process painfully loud sounds. Until now, researchers had been mystified as to the function of these neurons, which make up about 5 percent of the neurons in the inner ear.

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.

(more…)

Nature Neuroscience, October
Going to clown college could pay off: A new study found that learning to juggle increases the amount of white matter in the brain. These areas of the brain consist of the axons that stretch away from the neuron cell bodies where computation takes place, and can be thought of as the brain’s wiring system. The researchers studied volunteers’ brains before and after a six week juggling course, and determined that the changes weren’t linked to skill level, because both dexterous and clumsy students showed the same brain changes. It was the process of learning and practicing a new skill that bulked up the brain, researchers declared.

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.

(more…)

Proceedings of the National Academy of Sciences, October 6
PNAS was a grab bag of oddball findings this week. In one study, archaeologists argued that hoards of coins buried by ancient Romans not only serve as a measure for societal instability, they also provide clues about population changes in the republic. Since citizens presumably planned to dig up their hidden coins again in order to spend them, the researchers say, those hoards left behind indicate people who died or fled. In another study, a medical research team stirred together a bunch of buzzwords–nanotechnology, gene therapy, and stem cells–and found a promising way to aid potential stem cell therapies. While stem cells can rapidly grow into any kind of new tissue, they aren’t always able to encourage new blood vessels to grow so that the tissue stays alive. The team used nanoparticles to deliver a key gene, which spurs the growth of blood vessels, to the developing stem cells. The study suggests that this approach may be safer than using viruses as delivery agents.

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.

(more…)

Science, October 2
It’s not every day that scientists make an announcement that reshapes our theories of how modern humans came to be–and indeed, the research published in Science was 17 years in the making. Back in 1992, anthropologists unearthed fossilized hominid remains in Ethiopia, eventually finding bone fragments from 35 individuals, including a partial skeleton from a female they nicknamed Ardi. The new species, named Ardipithecus ramidus, lived 4.4 million years ago, and it brings us closer than ever before to the ancestral species that gave rise to both humans and apes. Researchers were surprised, however, to find that Ardi bore little resemblance to chimps, our closest living primate relatives.

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.

(more…)

Science, September 25
The week’s biggest news: there’s water, water everywhere in our solar system, or at least on our moon and on Mars. First, a trio of studies reported on the latest findings from the moon, where an Indian orbiter and two NASA probes detected the chemical signature of water all around the moon, not just in the permanently shadowed polar craters where scientists think ice might lurk. But researchers say the water isn’t sitting around in pools–it’s bound up with rocks and minerals in the top few millimeters of moon dust. In the Mars finding, researchers looked at five craters recently created by meteor impacts, and discovered that subterranean ice had been kicked up to the surface. The presence of ice on Mars wasn’t a surprise, but the quantity of it was–researchers say there may be ice sheets hundreds of miles across just beneath the surface.

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.

(more…)