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4 February 2012 | NewScientist | 17 Do baby pulsars cry cosmic-ray tears? TALK about enfants terribles. Baby pulsars may unleash torrents of the highest energy particles known, explaining the provenance of the ultra-high- energy cosmic rays that hit Earth. Charged particles with energies up to 10 20 electronvolts slam into our atmosphere from time to time, but their source has been a mystery. Pulsars – ultradense stars formed during supernova blasts – are one candidate, but it has not been clear if the particles they shed could make it through the dense shroud of stellar shrapnel that surrounds the stars. Now Ke Fang and colleagues at the University of Chicago have modelled these particles and found that they can escape within the first year of a pulsar’s life. At that time, the pulsar’s spin, which gradually slows, is still fast enough to shoot out high-energy particles, and the supernova debris has spread out enough to allow those particles to escape (arxiv.org/ abs/1201.5197). “The most energetic particles may come from the smallest stars,” says Fang. “Pulsars are certainly violent little fellows,” agrees Jim Matthews of Louisiana State University in Baton Rouge. Potent anti-cancer weapon forged in silver SILVER may have just become even more precious. The metal packs as much of a punch against cancer cells as a leading chemotherapy drug, and could reduce the negative side effects that accompany such treatment. Cisplatin, used to treat a range of cancers, contains platinum. The drug is formed from groups of molecules attached to a platinum atom, creating a compound that reacts with DNA in cancer cells. It is the molecules surrounding the metal that determine how reactive the compound is. Previous studies have hinted that silver compounds could also kill cancer cells. So Diana Monteiro from the University of Leeds, UK, and colleagues subjected silver to the same treatment as platinum to see if they could make an effective cancer drug. The team attached different types of carbene ligands to the silver atoms before incubating varying concentrations of the compound with breast and colon cancer cells for six days. The silver complexes proved to be as effective as cisplatin in AH REF! Now you have an excuse for thinking your team always performs best. Your brain perceives the actions of people in your own team differently to those of a rival team. Pascal Molenberghs at the University of Queensland in Brisbane, Australia, divided 24 volunteers into two teams and had them judge the speed of hand actions performed by two people, one from each team. As expected, most of the volunteers were biased towards their own team, judging their players as faster, even when the two actions were performed at identical speeds. Surprisingly, brain scans taken during the task showed that this bias arises from differences in brain activity during perception of the hand action and not during the decision-making process. The work will appear in Human Brain Mapping. Louise Newman, a psychologist at Monash University in Melbourne, Australia, says the research is an important step to unravelling the mechanisms of how people develop perceptions of “in-groups” and “out-groups”. This can inform our understanding of racism and discrimination, she adds. Blame your brain for your bias DAVE SANDFORD/NHLI/GETTY attacking both types of cancer cells. Complexes containing a ligand which had two bonds were more effective than those with a single bond, probably because they are more stable – meaning the compound breaks down more slowly and is active for longer (Dalton Transactions, DOI: 10.1039/C2DT12399A). Crucially, silver is less toxic to normal cells than platinum. Charlotte Willans, also at Leeds, says it is an important step in the quest for effective, non-toxic cancer treatments. Extreme heat ages vital crop IT COULD be much harder than we thought to feed everyone in a warmer world. Hot spells are cutting wheat yields in northern India, and models of global warming’s effect on crops may have underestimated the problem by a huge amount. David Lobell of Stanford University in California used nine years of satellite images to track when wheat in the Ganges basin of India turned from green to brown, a sign that the plants had aged and the grain was no longer growing. He found the wheat turned brown earlier when average temperatures were higher. The data suggest that yield losses on the Ganges plain from an average warming of 2 °C may be 50 per cent greater than thought (Nature Climate Change, DOI: 10.1038/ nclimate1356). “This is an early indication that a situation that was already bad could be even worse,” says Andy Challinor of the University of Leeds, UK. Earlier studies suggested that, by 2050, warming could cut wheat yields by 30 per cent in places like India – a figure that may now be optimistic. Yet global yields need to rise 50 per cent by then to feed the world’s growing population. Wheat breeders are urgently seeking ways to help the plants cope, such as expanding their root systems to reduce water stress. NARINDER NANU/AFP/GETTY For new stories every day, visit newscientist.com/news
