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貢獻一下JJ的RC文章

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楼主
发表于 2008-10-26 20:24:00 | 只看该作者

貢獻一下JJ的RC文章

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 JJ_RC
        

五.科學家重新評估宇宙射線的危害

根據描述,找到網路上的這篇文章,應該不會錯

請享用


    


    

http://www.sciam.com/article.cfm?id=updates-november-2007


    

Radiation
Redux


NASA has worried that cosmic rays could undermine a human voyage to Mars. New simulations and
calculations, though, suggest that such lengthy exposure to space radiation may
pose only half the health risk that NASA had expected.


    

The best U.S. space
radiation simulations take place at Brookhaven National Laboratory’s Booster
accelerator, where a facility for space research opened in 2003. The device
sends beams of protons, iron and other cosmic elements down a 100-meter-long
tunnel to strike human cells, mice and rats. Biologists then assess DNA damage.
The Booster has enabled NASA to conduct regular, more realistic experi-ments
beyond the one-week-a-year timetable of the past.


    

One interesting
preliminary finding, according to Brook-haven radiobiologist Betsy Sutherland,
is that the lower a
proton’s energy, the more damage it does
. Apparently, lower-energy
protons, which travel more slowly, have more time to interact with tissues. In
lowering its assessment of risk, NASA also factored in astronauts’ better-than-average health
and switched from
“whole-body” radiosensitivity
to
organ-by-organ measurements, where new studies have found lower risks for lungs,
breasts and the blood system.


    

Such analyses,
if they prove correct, could mean that Mars mission astronauts might not need
radioprotective drugs at all, says Francis Cucinotta, NASA’s chief scientist
for human radiation research. For solar storms and other acute risks, he adds,
“we might want to carry them just in case.” Possible drugs include
retinoids—vitamins that work as antioxidants—and compounds that delay cell
division long enough for damaged cells to repair themselves before they can
propagate mutations.

            —John Dudley Miller


沙发
发表于 2008-10-26 20:38:00 | 只看该作者

顶~!

板凳
发表于 2008-10-26 21:11:00 | 只看该作者
请问没有重写或者改动吗?一模一样?
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