首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
In 1751, Swedish botanist Carolus Linnaeus came up with the novel idea of using flowers as clocks. Morning glories open their tr
In 1751, Swedish botanist Carolus Linnaeus came up with the novel idea of using flowers as clocks. Morning glories open their tr
admin
2016-08-19
92
问题
In 1751, Swedish botanist Carolus Linnaeus came up with the novel idea of using flowers as clocks. Morning glories open their trumpet-like petals around 10 a. m. , water lilies at 11 and so on through evening primroses and moonflowers. A full array of these blossoms, planted in a circle, could indicate the time. It was a whimsical notion. But some 250 years later, scientists are seriously interested in the timekeeping mechanisms of nature. "They’re so ubiquitous, they’re almost a signature of life," says molecular neuroscientist Russell Foster of Imperil College, London.
From cockroaches to humans, Foster explores these internal clocks in a fascinating new book, Rhythm of Life, co-authored with British science writer Leon Kreitzman. The author show how the daily patterns known as circadian rhythms influence far more than our sleep. Heart attacks are more common in the morning. Women tend to go to labor in the evening. Severe asthma prevail at night. Although we may jet across time zones, circadian rhythms rule. The book traces the century-long quest to unravel their mechanisms, with some starting outcomes—including the recent discovery that certain genes switch on and off in 24 hour cycles. Even our responses to medicines may depend on when we take them.
Nature has devised internal clocks for a simple reason: they aid survival. "The early bird really does get the work,"—thanks to a silent wake-up call before dawn. A mimosa plant spreads its fernlike leaves during the day to create the maximum surface area for photosynthesis, then folds them up at night to reduce water-vapor loss. It’s not a mere response to light. "They do this even when kept in the dark," says biologist Eugene Maurakis of the Science Museum of Virginia.
In humans, the master clock is a tiny clump of cells in the brain called the suprachiasmatic nuclei. The clocks is reset daily by signals from a novel type of photoreceptor in the eye that Foster discovered. "The blind rely on it, too, provided their eyes haven’t been removed," he says. The result is an orchestrated series of biological events that unfolds in sequence. In the hours before breakfast, the body releases digestive enzymes gradually to be ready for the first meal. Temperature and blood pressure rise in preparation for the day’s demands. This helps explain the morning increase in the heart attacks. Cells reproduce at set times. Hormones rise and fall—many of them according to a predetermined schedule.
The implications for medicine are profound. By timing treatments to complement daily changes in biochemistry, the authors argues, we can boost efficacy and reduce side effects. In one seminal trial, medical oncologist William Hrushesky of the Dorn V. A. Medical Center in Columbia, S. C. , found that by simply reversing the times when he administered two chemotherapeutic drugs, he could extend survival in women with advanced ovarian cancer from 11 percent at five years to 44 Chronobiology International, more than a dozen ailments can currently benefit from carefully timed treatments. In one recent study, he notes, something as simple as low-dose aspirin at bedtime reduced the rate of preterm deliver in pregnant women at risk for hypertension from 14 percent to zero. Aspirin in the morning had little effect. Surprised? Not to Foster and Kreitzman. As they show, timing is everything.
Which of the following is INCORRECT concerning the mimosa plant?
选项
A、The mimosa plant unfolds its leaves to get light.
B、The mimosa plant folds leaves to prevent water from losing at night.
C、The mimosa plant devises internal clocks in order to survive.
D、If the mimosa plant is placed in the dark, the internal clocks don’t work very well.
答案
D
解析
推断题。根据第三段倒数第一、二句可知,这不仅仅是对光的反应。弗吉尼亚科学博物馆的生物学家Eugene Maurakis说:“它们在黑暗中也如此。”可以判断[D]为错误表述,故为答案。第三段第三句说含羞草在白天时舒展叶子,从而使尽可能大的表面进行光合作用,而晚上为了防止水分蒸发,含羞草的叶子会折叠起来。[A]、[B]分别为这两层意思的同义表达,故排除;第三段开头提到,自然界有内部计时功能,原因很简单:内部计时功能帮助它们生存下来。因此[C]也是原文的表述,故排除。
转载请注明原文地址:https://kaotiyun.com/show/pC7O777K
0
专业英语八级
相关试题推荐
Lastyear,whensquattersbrokeintoAnnKeen’shouseonaquiet,suburbanstreetinBrentford,westLondon,theneighbours’rea
Lastyear,whensquattersbrokeintoAnnKeen’shouseonaquiet,suburbanstreetinBrentford,westLondon,theneighbours’rea
OnaLosAngelesstreetcornerin2000,Iwasthe"insideman"inaclassiccongamecalledthepigeondrop.AmagiciannamedDa
In1751,SwedishbotanistCarolusLinnaeuscameupwiththenovelideaofusingflowersasclocks.Morninggloriesopentheirtr
In1751,SwedishbotanistCarolusLinnaeuscameupwiththenovelideaofusingflowersasclocks.Morninggloriesopentheirtr
AsIwrite,agentle,muchneededrainisfallingthismorning.IthasbeenadryspringhereinVermont.Sodryinfact,thatt
"Iboughtsomeroses"______"Iboughtsomeflowers".
IthoughtthatitwasaSundaymorninginMay,thatitwasEasterSunday,andasyetveryearlyinthemorning.Iwasstandinga
In1751,SwedishbotanistCarolusLinnaeuscameupwiththenovelideaofusingflowersasclocks.Morninggloriesopentheirtr
随机试题
A.卵泡刺激素B.黄体生成素C.抑制素D.孕激素刺激雌激素生成的关键激素是()
根据个人独资企业法律制度的规定,下列各项中,可以作为个人独资企业出资的有()。
节点③中,栏杆立柱与踏步连接处的做法,以下哪项是正确的?
( )方法有助于检查各单项工程和单位工程投资构成是否完整,有无重复计算或缺项。
下列关于职业病说法正确的是()。
进行证券组合投资可以()。
商业银行应根据统一法人的要求,在其授信业务范围内对有关授信业务职能部门、分支机构及授信业务岗位进行授权,这遵守的是()。
2016年5月10日,甲公司与乙企业签订了一份买卖合同,合同约定:乙企业向甲公司购买20吨药材;合同签订后5日内,乙企业向甲公司支付定金10万元;交货时间为7月底,交货地点为乙企业的库房,验货后3日内付清货款。2016年7月10日,甲公司委托丙运输公司将药
______maybedefinedasanykindofengagingwiththelanguageonthepartofthelearners,usuallyundertheteacher’ssupervi
在两个公司网站之间建立一条租用(DDN)线路连接时遇到以下问题。过去这两个网站是通过ISDN线路使用DDR来连接的,由于信息量的增加,选用256kbps的租用线路更加合算。连接方式如图1-25所示。现在决定为每个路由器配一个NAN串
最新回复
(
0
)