Health & Science
Climate change stalls jet stream
Climate scientists have long understood that global warming can make extreme weather events like the Texas heat wave of 2011 and last year’s floods across Europe more common. But new research suggests this rise in extreme weather isn’t simply due to increasing atmospheric temperatures: Climate change might also be altering the flow of planet-scale air patterns like the jet stream. Normally, the jet stream moves from west to east across the Northern Hemisphere, with ribbon-like air currents that undulate from the equator to the North Pole. A large temperature difference between the tropics and the Arctic causes the winds to blow faster. But when the difference is smaller, the jet stream slows and whole regions can be left under the same weather for long periods, turning hot days into heat waves, dry spells into droughts, and wet conditions into floods. Using temperature records and climate model simulations, an international team of researchers found that such stalls are increasing in frequency, largely because climate change is causing the Arctic to warm faster than the rest of the planet.“Human activity has been suspected of contributing to this pattern before,” study leader Michael Mann tells The Guardian (U.K.). “But now we’ve uncovered a clear fingerprint.”
Beating paralysis with the brain
A quadriplegic man can now feed himself again after a breakthrough procedure that has allowed him to control his hand with the power of thought. Bill Kochevar, 56, suffered a severe spinal cord injury in a bicycle accident eight years ago and was left completely paralyzed from the neck down, reports NPR.org. In order to circumvent his damaged spine, researchers at Case Western Reserve University in Cleveland surgically implanted two electrodes in the motor cortex region of his brain, and 36 inside his arm. The brain implants are linked to a computer, which translates brain signals into electrical impulses that trigger movement in Kochevar’s hand, wrist, elbow, and shoulder. After four months of training the system to recognize the signals that correlate with his desired actions, Kochevar is now able to drink from a cup and eat with a fork. “I thought about moving my arm and I could move it,” he says. “I’m still wowed every time I do something.” The system is not yet ready for use outside a lab, but the team hopes to streamline the technology so that it becomes routine treatment for paralysis.
Scientists studying age-related disease may be one step closer to a therapy that could help reverse the ravages of time. Researchers in the Netherlands have been investigating senescent cells, “zombie” cells that have stopped dividing and that can contribute to illnesses such as heart disease, arthritis, and diabetes. For a new study, the team designed a molecule to selectively kill these cells in mutant mice that age rapidly, without harming healthy cells. The therapy restored the rodents’ kidney function, stimulated the growth of their fur, and improved their stamina. The researchers are now studying whether the mice also live longer. They believe the procedure could potentially be used to treat age-related disorders in humans and even to kill cancer cells, which share certain features with senescent cells. “It’s definitely a landmark advance,” University of Montreal biologist Francis Rodier, who wasn’t involved in the study, tells Science. “This is the first time that somebody has shown that you can get rid of senescent cells without having any obvious side effects.”
Health scare of the week
Marathons tax the kidneys
Running a marathon may be about as traumatic for the kidneys as heart surgery, reports CNN.com. To assess how running 26.2 miles affects kidney function, researchers from Yale University collected blood and urine samples from a group of people just before they ran the Hartford Marathon, and then immediately afterward. They found that after the race 82 percent of the runners had signs of acute kidney injury—likely due to dehydration— as well as reduced blood flow to vital organs and a rise in core body temperature. “Almost everybody had a significant increase in the novel markers of injury, inflammation, and repair,” says study leader Chirag Parikh. The researchers found these effects were only temporary, and reversed within 48 hours. But they warned that the long-term impact of running marathons remains unknown, and said their findings emphasize that runners should stay well hydrated and avoid medications that are toxic to the kidneys.