“We have an amazingly simple picture of the universe,” says Princeton University astrophysicist Michael Strauss. “Of course, we don’t understand that picture—we don’t know what dark energy is, and we don’t know what dark matter is.” [Scientific American]
To get a better handle on these “dark” forces, which we can’t detect with our puny human equipment, researchers Christian Marinoni and graduate student Adeline Buzzi from the University of Provence used an approach that’s actually been around longer than the idea of dark energy–a 1979 theory from Charles Alcock.
The Lake Tahoe area on the California-Nevada border can be appreciated from a variety of perspectives: Some people focus on the stunningly beautiful alpine lake nestled in the Sierra Nevada range, while others see it as a mecca for skiers and winter sports enthusiasts. When climate scientists look around, though, they see change. Two recent studies suggest that global warming is already altering that beloved ecosystem.
The first report (pdf), produced by researchers at the UC Davis Tahoe Environmental Research Center, predicts that snowpack melts over the next century will have a drastic impact on both winter tourism and the water supply.
The average snowpack in the northern Sierra Nevada mountains that ring the lake on the California-Nevada border will decline by 40 to 60 percent by 2100 “under the most optimistic projections,” says the report from three researchers at the University of California, Davis.
Under less optimistic models, the melt-off could be accelerated. By the end of the century, precipitation in the region “could be all rain and no snow,” and peak snowmelt in the Upper Truckee River — which is the largest tributary flowing into Lake Tahoe — could occur four to six weeks earlier by 2100, the report says. [New York Times]
A neuroscientist who has spoken out in support of animal testing is in the news again after a militant animal rights group sent razor blades and a threatening note to his house. The group claims that the razor blades were contaminated with HIV-infected blood.
The researcher, J. David Jentsch, who studies addiction and schizophrenia at UCLA, explains the incident:
“About a week ago I was going through my mail in my kitchen and I opened a letter and razor blades spilled out on the floor. It was the first sign something was nefarious,” he said. “The letter inside contained quite specific and heinous acts of violence to kill me.” [CNN]
Jentsch made headlines last year when he staged a pro-test rally in support of (humane) animal research after an animal rights group fire-bombed his car in his driveway. The threats and harassment of Jentsch and other department employees have continued, but Jentsch seems undaunted and undeterred.
In a bit of good news for private citizens dreaming of trips to orbit, the Federal Aviation Administration has just declared that trips aboard private spaceships needn’t be one-way.
The private space company SpaceX received the FAA’s first-ever commercial license permitting the re-entry of a spacecraft into the Earth’s atmosphere from orbit, which will allow a December test of its “space taxi” to proceed. In June, SpaceX successfully launched its Falcon 9 rocket and a mock-up Dragon crew capsule. The next step is to send the rocket and capsule up to orbit, and then bring them safely back down to Earth with a splash-down landing in the Pacific Ocean. That test is currently scheduled for December 7.
The Dragon is controlled during descent using “Draco” rockets and SpaceX say it should be capable of landing within a small distance – say a few hundred metres – of a designated point. The company hopes to bring it down on land once initial flights have proved the system. [Register]
A drug called Truvada seems to be able to prevent HIV infection from taking hold in the body when taken regularly. The once-a-day pill combines two anti-retroviral drugs, and was found to reduce new HIV infections in a study of 2,500 gay men. But there are two big issues: compliance and cost.
In the study, which was published in the New England Journal of Medicine, men who took the pill were 44 percent less likely to contract the disease than those on placebo. But when the researchers looked only at the men who took the pill faithfully, the number jumped to 90 percent.
“These results represent a major advance in HIV-prevention research,” says physician Kevin Fenton of the Centers for Disease Control and Prevention in Atlanta. “For the first time, we have evidence that a daily pill used to treat HIV is partially effective for preventing HIV among gay and bisexual men at high risk of infection.” Fenton cautions, however, that the results don’t warrant abandoning other proven prevention techniques. [Science News]
While the results are certainly promising, it remains to be seen if at-risk people would take a pill every day.
[M]any men in the study failed to take all their pills, and some clearly lied about it. For example, some who claimed to take them 90 percent of the time had little or no drug in their bloodstreams. Although the pills caused no major side effects in the study, some men disliked the relatively minor ones, like nausea and headaches. [New York Times]
Forensic scientists of the future may soon have a new tool at their disposal. Given a drop of blood, researchers in the Netherlands have roughly determined the age of the person it came from. But for now, it really is rough–the researchers found they could only estimate a person’s age to within 9 years.
Currently, a crime scene investigator who obtained a spot of blood can check its DNA to see if it matches a known suspect or someone in a law enforcement database, and can use the DNA to determine a few other characteristics like gender and eye color. But age is tougher to estimate. Lead researcher Manfred Kayser, who works on forensic molecular biology at Erasmus University Medical Centre, explains that the best methods of determining age rely on testing bones or teeth, but he wanted to find a method that didn’t require skeletal remains.
Traumatic brain injury has become the signature war wound for soldiers serving in Iraq and Afghanistan–and new research suggests that soldiers may not be adequately protected against the explosions that cause these injuries. By modeling how blast waves propagate through a soldier’s head, an MIT research group found that current combat helmets don’t offer much protection, because the blast waves from improvised explosive devices (IEDs) can enter the skull through the face.
“There’s a passageway through those soft tissues directly into the brain tissue, without having to go through bone or anything hard,” said Raul Radovitzky, an aeronautical engineer at the Massachusetts Institute of Technology. [LiveScience]
In the study, which was published online in Proceedings of the National Academy of Sciences, the researchers created their own computer model based on a real person’s brain scans; what they found actually contradicted findings from earlier, rougher models. A previous study, published in August, suggested that current helmet design actually increases brain injuries during an explosion by focusing and intensifying the blast waves inside the helmet.
Researchers have identified 30 genes that play a role in the onset of menstruation in girls. Some of these puberty genes have previously been linked to body weight and fat metabolism, strengthening the connection between the obesity epidemic and the early onset of puberty in industrialized nations.
For the study, published in Nature Genetics, researchers analyzed 32 genome-wide association studies that included more than 87,000 women from the United States, Europe and Australia, and then replicated the results in a further 14,000 women. Of the 30 genes that they found play a role in the timing of women’s first periods, four genes are linked to body mass index, three play a role in metabolism, and three are involved in hormone regulation.
Study co-author, Dr Enda Byrne of the Queensland Institute of Medical Research says the results from this study show that many of the genes that increase risk for weight gain and obesity in adulthood, also influence the onset of puberty. “This supports the idea that the body launches into puberty once it reaches a certain level of nutrient stores and therefore children who are overweight are more likely to undergo early puberty,” says Byrne. [Australian Broadcasting Corporation]
World carbon emissions fell by 1.3 percent in 2009, most likely due to the global recession, says a report from the Global Carbon Project published today in Nature Geoscience. Emissions were originally expected to drop further (about 3 percent, as estimated from the expected drop of world GDP), but China and India’s surging economies and increasing carbon output countered the decreases elsewhere.
The largest decreases occurred in Europe, Japan and North America: 6.9% in the United States, 8.6% in the U.K., 7% in Germany, 11.8% in Japan and 8.4% in Russia. The study notes that some emerging economies recorded substantial increases in their total emissions, including 8% in China and 6.2% in India. [USA Today]
There is some good news from the report. It seems the atmospheric CO2 concentrations didn’t jump as much as they were expected to, which means the world’s carbon sinks were performing better.
While emissions did not fall much, the amount of CO2 in the atmosphere increased by just 3.4 gigatonnes – one of the smallest rises in the last decade. Friedlingstein says the land and marine sinks performed better in 2009, because the La Niña conditions in the Pacific meant the tropics were wetter, allowing plants to grow more and store away more carbon. [New Scientist]