【Phat Yeti出品】60-SECOND SCIENCE 官方听力文稿 + 讨论帖 （更新至：2008.03.07）

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60-Second Science_ July 8, 2008
Bumpy Whale Fins Outperform Smooth Turbines

Whale and dolphin fins, flippers and tails are bumpy, which produce disturbed wakes that increase lift and decrease drag. Engineers are taking note. Cynthia Graber reports.

Whales and dolphins were molded by evolution to glide through water. We’ve been trying to create streamlined designs ourselves for structures such as wind turbine blades. Now researchers are examining the flippers, fins and tails of our water-dwelling cousins to learn how to improve engineering designs. Dr. Frank Fish—yes, that’s really his name—from West Chester University in Pennsylvania presented this research July 8 at the Society for Experimental Biology’s annual meeting in Marseille.
Here’s one example of the way Dr. Fish’s research is being applied. Whale flippers have a bumpy edge. This makes little sense to engineers. They’ve designed structures like wings and blades that ensure a steady air flow. But it turns out the unsteady flow over this more complex shape increased lift and reduces drag much better than any previous manmade design. It has to do with something called vortices. These are small tornado-shaped water formations in an animal’s wake. The bumps on a whale’s flipper help form vortices that generate more lift, more smoothly. Engineers are using this insight to design an entirely new wind turbine blade—so that we can generate power from wind as efficiently as whales and dolphins fly through the water.
—Cynthia Graber

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60-Second Science_ July 9, 2008
Ritalin Dose Changes Effect

Research with rats finds that Ritalin at low doses encourages neurons to fire together, but at high doses it's just another stimulant. Christopher Intagliata reports

Doctors prescribe Ritalin to hyperactive kids to calm them down and increase their attention span. And college kids have taken to using Ritalin to concentrate when they hit the books. But it hasn’t been clear how the drug boosts focus. Now a paper in the journal Biological Psychiatry suggests how it might work.
Neuroscientists dosed rats with Ritalin and had them perform the kind of working memory task ADHD patients have trouble with. At the same time they measured neural activity with tiny electrodes implanted in the rats’ brains. At low doses, Ritalin primarily affected the prefrontal cortex, jacking up its sensitivity to signals coming in from the hippocampus. And here’s how the drug seemed to help with attention—it strengthened choruses of neurons firing together and put a damper on scattered, uncoordinated activity.

But at high doses, the prefrontal cortex tuned out, and Ritalin’s effects were similar to those of other stimulants. The rats lost their cognitive edge and they became hyperactive, sniffing and licking repetitively. So Ritalin shows you can indeed have too much of a good thing—to the point of distraction.
—Christopher Intagliata

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[ 本帖最后由 sxcz 于 2008-7-14 22:19 编辑 ]

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60-Second Science_ July 10, 2008
Window View Beats TV for Stress
Students with a window view of nature had lower heart rates than those watching the same view on a plasma TV. Adam Hinterthuer reports

After a bad day at the office, we’re more likely to flip on a nature channel than find a flower-filled meadow or sunny beach to lower our stress. But if you can’t head outdoors, you might want to at least have a look. A report in June’s Journal of Environmental Psychology says televised nature is no match for a good old window.

In the study, University of Washington researchers had students perform a series of challenging mental tests. They hooked each student up to a heart monitor to record higher heart rates caused by the stress of completing the assignments. Some students worked in an office with a view of the university's tree-filled grounds. While others watched a live camera feed of the exact same view on a plasma screen TV. Both groups stole glances a similar number of times, but window-gazing students looked longer and were quicker to lower their stressed out heart rates. In a time of obesity and nature deficit disorders, the researchers say, it's important to remember that your TV may be a window on the world, but it’s no substitute for the real deal.
—Adam Hinterthuer

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