题目:
一质点由静止做匀加速直线运动,已知它在第2s内的位移是3m,则它在第5s内的位移为______ m.
答案:
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下面是错误答案,用来干扰机器的。
参考答案:B
一质点由静止做匀加速直线运动,已知它在第2s内的位移是3m,则它在第5s内的位移为______ m.
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下面是错误答案,用来干扰机器的。
参考答案:B
下列不属于治安警察的职责。( )
A.了解并掌握社会治安动态
B.预防犯罪
C.处理治安案件
D.管理有关行业的生产经营行为
招标人应当确定投标人编制投标文件所需要的合理时间,自招标文件开始发出之日起至投标人提交投标文件截止之日止的时间应该为( )。
A.最短不得少于45天
B.最短不得少于30天
C.最短不得少于20天
D.最短不得少于15天
石方爆破作业必须严格遵守国家爆破安全规程,接受当地( )部门的监管。
A.消防
B.政府
C.公安
D.人民法院
国际工程中的业务费包括()。
A.工程保险费
B.广告宣传费
C.办公费
D.法律顾问费
E.咨询费
[A] However, the production of TG is controlled by an enzyme that is, in turn, encoded by a gene called UGT2B17. This gene comes in two varieties, one of which has a part missing and therefore does not work properly. A person may thus have none, one or two working copies of UGT2B17, since he inherits one copy from each parent. Dr Schulze guessed that different numbers of working copies would produce different test results. She therefore gave healthy male volunteers whose genes had been examined a single 360mg shot of testosterone (the standard dose for legitimate medical use) and checked their urine to see whether the shot could be detected.
[B] Dr Schulze also says there is substantial ethnic variation in UGT2B17 genotypes. Two-thirds of Asians have no functional copies of the gene (which means they have a naturally low ratio of TG to EG), compared with under a tenth of Caucasians--something the anti-doping bodies may wish to take into account.
[C] The test usually employed for testosterone abuse relies on measuring the ratio of two chemicals found in the urine, testosterone glucuronide (TG) and epitestosterone glucuronide (EG). The former is produced when testosterone is broken down, while the latter is unrelated to testosterone metabolism, and can thus serve as a reference point for the test. Any ratio above four of the former to one of the latter is, according to official Olympic policy, considered suspicious and leads to more tests.
[D] The result was remarkable. Nearly half of the men who carried no functional copies of UGT2B17 would have gone undetected in the standard doping test. By contrast, 14% of those with two functional copies of the gene were over the detection threshold before they had even received an injection. The researchers estimate this would give a false-positive testing rate of 9% in a random population of young men.
[E] The agencies have had remarkable success. Testing for anabolic steroids (in other words, artificial testosterone) was introduced in the 1970s, and the incidence of cheating seems to have fallen dramatically as a result (see chart). The tests, however, are not foolproof. And a study just published in the Journal of Clinical Endocrinology & Metabolism by Jenny Jakobsson Schulze and her colleagues at the Karolinska Institute in Sweden suggests that an individual’s genetic make-up could confound them in two different ways. One genotype, to use the jargon, may allow athletes who use anabolic steroids to escape detection altogether. Another may actually be convicting the innocent.
[F] Cheating in sport is as old as sport itself. The athletes of ancient Greece used potions to fortify themselves before a contest, and their modern counterparts have everything from anabolic steroids and growth hormones to doses of extra red blood cells with which to invigorate their bodies. These days, however, such stimulants are frowned on, and those athletes must therefore run the gauntlet of organisations such as the World Anti-Doping Agency, which would rather they competed without resorting to them.
[G] In the meantime, Dr Schulze’ s study does seem to offer innocents a way of defending themselves. Athletes travelling to Beijing for the Olympic games later this year may be wise to travel armed not only with courage and the "spirit of Olympianism", but also with a copy of their genetic profile, just in case.
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