题干

据研究表明,近30年来我国境内喜马拉雅山区海拔5200米附近的冰湖(以冰雪融水为主要补给的)数量和面积有增加趋势。其主要原因是(  )

A:气温下降,蒸发减弱

B:气候变暖,冰川退缩

C:引水灌溉减少,节约用水

D:降水增多,雨水补给为主

上一题 下一题 0.0难度 选择题 更新时间:2019-09-10 01:39:16

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B

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Cure for tiredness?

    Staying up late is a potential battle between parents and kids. But the solution could be as simple as changing your meal time.

    Researchers at the University of Surry, UK, found that delaying meals could help change one of the internal body clocks. Besides a “master” clock in the brain, there are clocks in other parts of the body. They are usually synchronized according to factors including light.

    During the study, researchers tested 10 participants to examine the effect of changing meal times on their body clocks. The participants were given three meals ---breakfast, lunch and dinner. In the first stage, participants received breakfast 30 minutes after waking. Lunch and dinner followed, after 5-hour intervals. In the second stage, each meal was delayed by 5 hours. Right after each stage, blood and fat samples were collected.

    Results showed that later meal times greatly influenced blood sugar levels. A 5-hour delay in meal times caused a 5-hour delay in the internal blood sugar rhythms.

    The discovery showed that meal times are in line with the body clock that controls blood sugar levels.

    This is a small study but the researchers believe the findings could help jet lag sufferers and night-shift workers.

    In a study by the University of Surrey in 2013, researchers explored what happened when a person's body was changed from a normal pattern to that of a night-shift worker's.

    After people work through the night, over 97 percent of the body's rhythmic genes are disrupted(扰乱,使混乱).

    These findings explain why we feel so bad following a long flight, or after working at night, according to Simon Archer, one of the study's researchers.

    “It's like living in a house. There's a clock in every room in the house and in all of those rooms those clocks are now disrupted, which of course leads to chaos in the household,” fellow researcher DerkJan Dijk told the BBC.

    Changing meal times didn't affect the “master” body clock --- the one controlling when we get sleepy --- but it can reset the body clock that controls blood sugar levels. This wouldn't necessarily cure jet lag completely, but it might reduce the negative effects.

A study published earlier this year suggested that just a weekend camping trip could be enough to reset our body clocks. And now this latest research shows regular food schedules could play a key part too.