39. This is Scientific Americans' 60-Second Science. I am Cynthia Graber. This'll just take a minute.
Some genes that contribute to diseases can be traced back to what's known as a founder mutations. It's the first instance of that specific mutation, which then gets carried by all subsequent generations. Mutations in one's specific gene are known to give carriers a 69% greater risk of colon cancer by the age of 80. but it can be tough to figure out who has it. Luckily, the Mormon church keeps great family records. Researchers at the University of Utah were able to figure out that this mutation occurred in only 2 extended families, one in Utah and one in New York. So they suspected that somewhere in history lurked a founder. They used colonoscopy information, genetic analysis of family members and genealogical data, and Mormon archives to trace the mutation all the way back to one couple. When Mr and Mrs George Fry came to America from England in about 1630, they had no idea that they were bringing along the colon cancer risk genes. Fortunately, the Frys' hundreds of 21st century descendents can be monitored and treated at the first sign of the disease.
Thanks for the minute for Scientific Americans' 60-Second Science. I am Cynthia Graber.
我的听写稿.
Some genes thatcontribute to diseases can be traced back to what's knownas a founder mutations. It's the first instance of that specific mutation, whichthen gets carried by all subsequent generations.Mutations in one's specific gene are known to give carriersa 69% greater risk of colon cancer bythe age of 80. but it can be tough to figure out who has it. Luckily, theMormon church keeps great family records. Researchers at the University of Utahwere able to figure out that this mutation occurred in only 2 extendedfamilies, one in Utah and one in New York. So they suspectedthat somewhere in history lurked afounder. They used colonoscopy information,genetic analysis of family members and genealogical data, and Mormon archives to trace the mutation all the way back to onecouple. When Mr and Mrs George Fry came to America from England in about 1630,they had no idea that they were bringing along the colon cancer risk genes. Fortunately, theFrys' hundreds of 21st century descendents can be monitored and treatedat the first sign of the disease.
40. This is Scientific Americans' 60-Second Science. I am Cynthia Graber. This'll just take a minute.
If you feel the urge to lay your head down on the desk for a afternoon nap, here is something to tell your boss. A 90 minutes snooze will actually help you remember that new task you just learnt. Researchers at the University of Haifa published the results of their nap study in the journal Nature neuroscience. They tested 2 groups, each was asked to learn to bring their thumb finger together in a specific sequence. One took a 90-minute nap afterwards, the other didn°Øt. The group that slept had learnt the sequence better by nightfall. By morning the 2 groups had evened out, but researchers say the nappers improved more rapidly the next day. Then the scientists took another 2 groups. Both learnt 2 different thumb-to-finger sequences over a few hours. One group took a nap in between the 2 tasks. At night time, there was no difference between the 2 groups, but by morning, the nappers had learnt the first task better. Scientists say this shows that siestas helps engrave new tasks into a long term memory. Turns out that if you snooze, you win.
Thanks for the minute for Scientific Americans' 60-Second Science. I am Cynthia Graber.
If you feel the urge tolay your head down on the desk for a afternoon nap, here is something to tellyour boss. A 90 minutes snooze will actually help you remember that new taskyou just learnt. Researchers at the University of Haifapublished the results of their nap studyin the journal Nature neuroscience. They tested2 groups, each was asked to learn to bring their thumb finger together in a specific sequence. One took a 90-minute napafterwards, the other didn°Øt. The group that slept had learnt the sequencebetter by nightfall. By morning the 2 groupshad evened out, but researchers say the nappers improved more rapidly the nextday. Then the scientists took another 2 groups. Both learnt 2 different thumb-to-finger sequences over a few hours. One grouptook a nap in between the 2 tasks. At night time, there was no differencebetween the 2 groups, but by morning, the nappers had learnt the first taskbetter. Scientists say this shows that siestas helpsengrave new tasks into a long term memory. Turnsout that if you snooze, you win.
Nightfall:dusk siestas: an afternoon rest or nap, esp. one takenduring the hottest hours of the day in a hot climate.
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发表于 2011-11-25 22:45:24
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