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2019年07月17日 22:34:07

In the first hours of Semus life, hes on a huge learning land,在刚出生的几个小时里,莎木必须学会弯曲,less than a meter long, Semu must first perfect art of breathing and swimming.不超过一米,莎木必须完善这种呼吸和游泳的艺术。Bobbing up and down, Semus movements are jerky and uncoordinated. 上下摆动,莎木的动作很不协调。His tiny dorsal fin is still floopy from being squashed up inside long.它的背脊被妈妈挤压的松弛下来了。Puck doesnt let her baby out of her sight for a second.帕克不让它的孩子离开自己的视线。Until now, Puck is choosing to be alone with Semu, perhaps giving him time to adjust to his new world.到现在,帕克还是和莎木单独呆在一块。也许是给它时间,适应这个新世界。Then something remarkable thing happens as the rest of the beaches family start to arrive. 比奇家庭的其他成员悉数到达了,这很引人注目。As if to celebrate, Pucks daughters and grandchildren together into welcome the youngster into this close family.帕克的女儿,孙女们,像是在祝贺,欢迎最小的成员,加入大家庭。Whether she called him in will never be known, but at last, the rest of the beaches family meet little Semu.没人知道,是不是帕克把它们叫来的。家庭的其他成员,终于见过小莎木了。With her family around her, Puck can afford to relax, knowing their safety in numbers.家庭成员围绕着它,它很放松,此刻是安全的。 201405/297272济南哪个无痛人流医院比较好呢济南市历下区第二人民医院预约济南人流哪儿医院最好

济南妇保医院官网预约免费聊城市妇幼保健院治疗子宫肌瘤好吗Science and technology科学技术Athletic performance运动员的表现Faster, higher, no longer更快,更高已成往事Is it time to update the Olympic credo?是时候更改奥运会信条了?ON AUGUST 5th millions of people will watch the 100-metre final at the London Olympics.数百万人将在8月5日观看伦敦奥运会的一百米决赛。Many will wonder if anyone can repeat Usain Bolts feat in Berlin in , when the Jamaican clocked 9.58 seconds, lopping 0.11 seconds—aeons in a sprint—off the previous world record, which he set at the 2008 Beijing games.许多人都想知道谁能重现尔特奇迹,09年的柏林世界田径锦标赛上,尔特以9秒58的成绩刷新了自己在08年北京奥运会创下的记录,这缩短的0.11秒在短跑界已经算是巨大的超越了。One person who thinks this unlikely is Mark Denny.有人认为没人能做到,他就是马克丹尼。Another 0.11 seconds would take the time below what Dr Denny, from Stanford University, reckons is the absolute limit of human athletic performance in the 100-metre dash.在斯坦福大学的丹尼士看来,再缩短0.11秒就超过了运动员在百米冲刺表现中的极限。In 2008 Dr Denny published a paper in which he crunched through the highest speeds achieved each year in running events from sprints to the marathon, some dating back to 1900.2008年丹尼曾经发表了一篇论文,他在其中收集了从短跑到马拉松等每年的赛跑项目的最佳成绩,有的甚至可以追溯到1900年。A statistical technique called extreme-value analysis discerned trends and the maximum possible deviations from them.利用一种叫极限价值分析法的统计技术可以看到数据走向,并由此计算出最大可能性。For the 100 metres, the human speed limit is 10.55 metres per second.就100米而言,人类的速度极限是每秒10.55米。This translates to 9.48 seconds.所以人类一百米最好成绩应该是9.48秒。Predicting the limits of human athletic prowess has been a popular parlour game among number crunchers.估算运动员的能力极限是数据分析家们最热衷的室内游戏。One study from 1992 had female marathon runners drawing level with men by 1998, to complete the 42.195km course in just under two hours and two minutes.有一项研究在1992年到1998年间以统一标准要求男女马拉松运动员,即在2小时2分以内跑完42.195。A more recent analysis from 2004 suggested that male and female 100-metre times will converge in 2156, at 8.08 seconds.2004年的一项研究分析曾预示,到2156年,男女一百米运动员的成绩都将达到8.08秒。Nowadays sport statisticians view such calculations as flawed because they relied on linear extrapolations.现在的体育统计员们认为,这些计算还不尽完善,因为它们是以线性推断为基础的。They prefer to fit data to variants of a “logistic” curve.它们倾向于用数据去迎合“逻辑”曲线上的变量。This produces an S-shaped plot more in line with the intuition that performance starts off relatively flat.由此绘制出的S型图表更符合最初阶段相对平庸的表现。It then goes through a period of rapid improvement as more people take part and more systematic approaches to training and nutrition get more out of them.随着参与人数的不断增多和培养训练方式的更加系统化,这个图表会在一段时间内快速上升。It finally levels off as athletes inch towards the most a body can manage.但随着运动员逐渐接近生理极限,图表会慢慢趋于平缓。This aly seems to be happening.现在的情况似乎正是如此。According to Dr Denny female marathon runners have, in effect, reached their peak.丹尼士表示马拉松女运动员实际上已经达到顶峰。In a 2010 study Geoffroy Berthelot, of Frances National Institute of Sport, showed that performance in 23 out of 36 track-and-field events has stagnated since 1993.法国国家体育协会的杰弗罗伊贝森罗特在2010年的一项调查中指出,在36项田径赛事中,有23项的运动员表现自1993年以后就一直停滞不前。The remaining 13 have seen only small increments.而剩下的13项就算有所提高也是微乎其微。Pool performance表现欠佳In swimming, Dr Berthelot found that all 34 events have seen improvements since 2000, though this may have been aided by the now banned slick, full-body swimsuits which helped competitors in Beijing smash 22 world records.而在游泳界,贝森罗特士发现34项比赛自2000年起都有一定进步,虽然这可能要归功于现在禁止穿光滑的套身泳衣的规定,该规定曾帮助运动员在北京奥运会上打破了22项世界纪录。Before 2000, performance in 16 events had been becalmed, though not in the 400-metres individual medley, which may explain why Chinas 16-year-old Ye Shiwen shaved a second off the world record and in the final leg stoked controversy by being quicker than the mens medley champion.2000年之前,在16项游泳比赛中,运动员的表现已经出现瓶颈,但是400米混合泳除外,这也许解释了为什么中国的16岁小将叶诗文落后世界记录一秒并在最后一圈的速度甚至超过了男子混合泳冠军的表现会引发争议。But Alan Nevill, of Wolverhampton University in Britain, reckons this is within the bounds of possibility for the 400-metres womens freestyle: a proxy, albeit an imperfect one, for the last leg of the medley.但是英国伍尔夫汉普顿大学的艾伦奈维尔确认为,这在女子四百米自由泳中是可能出现的:虽然不太可能实现,但仍算混合泳最后一圈的一个指标Drugs and technological tricks aside, ensuring that future Olympics live up to their motto of “faster, higher, stronger” may thus require some other performance-boosting tricks.抛开兴奋剂使用和技术作假不说,要保以后的奥运会不辜负“更高,更快,更强”的信条,可能要采取一切其他的技巧来促进运动员的表现。Steve Haake, of Sheffield Hallam University in Britain, points to a notable blip in the figures for the 100-metre dash.英国谢菲尔德哈勒姆大学的史蒂芬哈基指出了一百米数据中一个明显的尖峰信号。In 1968 the average of the best times of the top 25 athletes was much better than trend.1968年世界排名前25的运动员的最佳成绩要比整体趋势好得多。This, Dr Haake explains, is because those Olympic games were held in Mexico City.哈基士认为这是因为当时的奥运会实在墨西哥城举办的。At an altitude of 2,240 metres the air there is a fifth thinner than at sea level, providing 20% less drag—a boon to sprinters who, unlike their endurance counterparts, run anaerobically, and so need not worry about the diminished supply of oxygen.在海拔高达2,240的地方,空气要比海平面稀薄五倍,因此阻力也下降了20%,这是短跑选手的福利,和耐力型长跑运动员不同,他们进行的是无氧跑步,所以也不必担心供氧不足的问题。Eight of the 25 best times that year were recorded at the games, and most of the remaining 17 were at higher-than-usual altitudes where athletes prepared for the main event.当年的25个最佳成绩中,有8个打破了世界纪录,剩下的17个中的大多数都出自海拔较高的地方,那儿的运动员都在为主赛事做准备。The reduced drag may have helped Bob Beamons 8.9-metre long jump, in which the American added 55cm to the world record.也许下降的空气阻力还帮助鲍勃比蒙取得了跳远8.9米的好成绩,由此美国又为世界纪录增加了55厘米。Of that, 31cm was down to a tail wind combined with the altitude.高海拔加上顺风让鲍勃多跳了31米。Statistics suggest that feats like those of Messrs Bolt and Beamon are increasingly improbable.统计数据表明,像尔特和比蒙这样的好成绩越来越难以出现。But are they impossible?但是绝无可能吗?Peter Weyand, of Southern Methodist University in Texas, has shown that whereas the peak force which elite sprinters apply to the track is more than four times their body weight, they can squeeze even more out of their muscles.德克萨斯州南卫理公会教大学的彼得韦安德表示鉴于顶尖的短跑选手所爆发出来的最大力量是其体重的4倍,他们的肌肉还是可以挤出更多力量的。Dr Weyand found that the forces generated while athletes hopped on one leg as fast as they could on a high-speed tmill were roughly twice as high as during running at top speed.韦安德还发现,运动员在一座高速运转的跑步机上尽可能快的单脚跳跃时所迸发出的力量大约是他们在以最快速度奔跑时所迸发出来的两倍。This translated into 30% more ground force.这就是说运动员在地面奔跑还能爆发出30%的力量。Since ground force is the main determinant of sprinting speed, Dr Weyands results imply that human muscles are capable of producing enough oomph to propel sprinters one-third faster than Mr Bolts record.既然地面力量是冲刺速度的主要决定因素,韦安德士的研究结果表示,人类肌肉还能释放出足够的力量,可以帮助运动员跑得比尔特年创下的世界纪录还要快三分之一。The reason they have not is that in the normal, two-legged gait the foot is in contact with the ground for only around one-tenth of a second, 0.05 seconds less than when hopping.之所以没有出现这样的情况是因为在正常情况下,双腿跑动时,脚和地面的接触时间仅有十分之一秒,比跳跃时少0.05秒。As a consequence, muscle fibres do not have enough time to contract to their full potential.所以肌肉组织没有足够时间释放它们的潜力。Although tapping all this force while sprinting seems biomechanically inconceivable, there may be scope for slight alterations in training and gait, focused on increasing the peak power available to sprinters.虽然从生物医学的角度来看,在短跑时发挥出全部力量似乎是难以置信的,但也许在训练和步伐上还有改进的余地,可以关注如何提高运动员所能调动出的最大力量。For his part, Dr Denny would be thrilled to see any athlete breach his limits, but he isnt putting any money on it.如果有人能打破这个极限丹尼士一定会很激动,但他可不会在这上面押钱。 /201402/276494济南妇幼医院治疗妇科炎症好吗济南第三人民医院挂号电话

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