楼主:医社区 时间:2017年12月16日 09:28:35 点击:0 回复:0
Whats a Fly Doing in Antarctica?南极有苍蝇?Sometimes the biggest finds are the smallest finds. Researchers examining a segment of siltstone taken from ground along the Beardmore glacier in Antarctica found something unexpected. They found a fly.有时候,重大发现源于很小的发现。研究人员在南极比尔德莫尔冰川采集回来的一块粉砂岩中意外地发现了苍蝇。Well, not exactly a fly. They found a fly fossil–its a segment of the exoskeleton, the protective shell, of a fly larva. While the larvae are still growing, they are protected by a thin shell. And where theres larval shell, there are flies. So what are flies doing in Antarctica? Its much too cold there for flies. And the closest fly-friendly location, South America, is thousands of miles away.准确地说,不是苍蝇,而是苍蝇的化石。一块保护幼虫的外骨骼。在薄壳的保护下,幼虫还在发育。幼虫的蛹壳明了苍蝇的存在。那么,苍蝇怎么会在南极呢?南极冰冷的气候不适宜苍蝇生长啊!反而,最适宜苍蝇生存的地方——南非,却远在几千里之外。Part of the answer is that the fly fossil is ancient–it was found with a number of other fossilized things that have been dated between three million and seventeen million years old. Its possible that the fly lived during a period when sea levels were much lower there than they now are. Lower sea levels means wider continents –think of standing on the edge of a beach and having the water pull back. And wider continents means its more likely that living things might travel across the gap.正解可能是因为这块苍蝇的化石和一起发现的其它化石可以追溯到300万到700万年前了。很可能,苍蝇生长的那个时期,海水没有现在那么高,这意味着陆地面积更大。想象自己站在海边,浪打回来。广阔的陆地面积让生物更有可能跨越于大陆间。Or maybe not. Maybe flies are much older than anyone thought. We know that what we now call Antarctica was once connected to both South America and Australia. But that was around eighty million years ago, and flies arent thought to be that old.另种可能是苍蝇在地球上生存的时间比我们想象的还要久远。要知道,现在的南极曾经和南美大陆及澳大利亚大陆是接壤的。但这也是8000万年前的事了,那时候,苍蝇已经在地球上了?Whatever the answer is, something in our understanding of the continents, the seas, or fly evolution has to be fixed. Thats one of the best things about science–a really big change can come from the discovery of something really small.不管究竟是什么,我们所认识的大陆、海洋、苍蝇进化的常识之一要得以修正。这就是科学的妙处,一个小小的发现或许能推翻重大定论。 /201301/220747Science and technology科学与技术Prevention of cancer预防癌症Wonder drug特效药Aspirin continues to amaze15:17:29For more than a headache治的不仅仅是头疼FOR thousands of years aspirin has been humanitys wonder drug.几千年来,阿司匹林就一直是人类的特效药。Extracts from the willow tree have been used for pain relief in folk medicine since the time of the ancient Greeks.从古希腊开始,在民间医药中,人们就用柳树的萃取物缓解疼痛。By 1897 a synthetic derivative acetyl salicylic acid of the plants active ingredient was created.1897年,这种植物中的有效成分的人工合成衍生物诞生了,This allowed aspirin to become the most widely used medicine in the world.于是阿司匹林变成了世界上应用最广泛的药品。In recent years its benefits as a blood-thinning drug have led to it being prescribed in low doses of around 50mg to reduce deaths from stroke and heart attack.最近几年,由于阿司匹林的防血凝功能,在用其治疗中风和心脏病的时候,剂量很小,维持在50mg的水平左右。There were also hints that aspirin may help prevent some cancers.也有迹象表明阿司匹林可以帮助预防一些癌症。But these were mostly based on observational studies, which can be misleading.不过这些结论大多都是在观察研究的基础上的,因而有可能产生误导。The gold standard of scientific evidence is the randomised controlled trial, preferably one with a lot of people and held over a long time.国际上科学据的标准是由随机对照实验得出的结果,尤其是那些有很多人参与又经过很长时间的实验。The results of just such a trial, published in the Lancet, suggest that aspirin is indeed an astonishing drug.而就是这样一份发表在《柳叶刀》上的论文表示阿司匹林的确是一种让人吃惊的药物。Peter Rothwell at the John Radcliffe Hospital in Oxford and his colleagues looked at deaths due to cancers during and after randomised trials of daily aspirin.来自牛津的约翰?拉德克里夫医院的彼得?罗思韦尔和他的同事们研究了在每日用阿司匹林的随机对照实验期间或者之后因癌症而死亡的病例。The trials had actually been started to look at how useful aspirin was for preventing heart attacks and strokes.这一实验本是为了研究阿司匹林在防止心脏病和中风方面的疗效的,Nevertheless, the data from the 25,570 patients enrolled in eight trials was also revealing about cancer.然而八项试验25570名患者的数据也揭示了阿司匹林对于癌症的疗效。In trials lasting between four and eight years, the patients who had been given aspirin were 21% less likely to die from cancer than those who had been given a placebo.在那些历时4到8年之间的实验中,用阿司匹林的患者因癌症而死亡的概率比那些用安慰剂的患者小了21%。These results were based on 674 cancer deaths, so are unlikely to represent the kind of statistical oddity that can beset studies on cancer risks that sometimes create headlines.这些结果是在674例癌症死亡病例的基础上得出的,所以不大可能是所谓的统计学上的例外。对癌症风险的研究会因这种例外而受挫,有时甚至会闹成大新闻。The benefits of aspirin were also apparent many years after the trials had ended.试验结束后的很多年后,阿司匹林的效果也仍旧明显。After five years, death rates for all cancers fell by 35% and for gastrointestinal cancers by 54%.五年后,所有癌症的死亡率下降了35%,而胃肠道癌症的死亡率则下降了54%。A long-term follow-up of patients showed that the 20-year risk of cancer death remained 20% lower in those who had taken aspirin.一项长期的病情跟踪报告显示,那些用阿司匹林的患者的20年内的癌症死亡风险比那些不用的低了20%。The study revealed that the effect takes time to accrue, so aspirin must be taken over a long period.这项研究揭示了阿司匹林的效果是随着时间而递增的,所以必须长期用才行。The latent period for improving oesophageal, pancreatic, brain and lung cancer was about five years of aspirin taking on a daily basis.每日用阿司匹林对改善食管癌,胰腺癌,脑癌和肺癌的潜伏期为5年,For stomach and colorectal cancer the effects took ten years and for prostate cancer about 15 years.对胃癌和结直肠癌则要花10年才能起作用,而前列腺癌则要15年。The means by which aspirin prevents cancer is not well understood.这意味着目前还不清楚阿司匹林到底是怎么预防癌症的。It is believed that it inhibits an enzyme that promotes cell proliferation in tumours.研究人员认为阿司匹林阻碍了一种在肿瘤内部促进细胞增殖的酶的活动。The researchers also found that small daily doses of aspirin were enough, and that taking more than 75mg conferred no additional benefits.研究者还发现,每天用小剂量的阿司匹林就已足够,剂量超过75mg后不会再增加效果。Those starting on aspirin in their late 40s or 50s benefit most.那些从四五十岁末就开始用阿司匹林的人得到的效果最好。Current guidelines on using aspirin for reducing the chances of a stroke or heart attack rightly warn of the small risk of ulcers and of dangerous bleeding in the stomach.目前在用阿司匹林治疗中风或者心脏病时,用药说明上会明确提醒有可能出现溃疡和危险性胃出血。These guidelines will probably have to be revised given the new findings.而鉴于这些新发现,这些说明很可能将要被修改了。However, it remains unlikely that popping aspirin will be recommended for everyone like a vitamin supplement.不过阿司匹林泡腾片不大可能像维生素补充剂一样被推广至每一个人。Aspirin is a highly cost-effective treatment:用阿司匹林是一种非常划算的治疗:taking it for five to ten years easily beats initiatives to screen for breast and prostate cancers.只要吃五到十年,就能打败那些让你做乳腺癌或者前列腺癌扫描的建议。To put it another way, ask yourself what a pharmaceuticals firm might charge for a drug that would reduce the chance of death by cancer by 20%—and then note that 100 days supply of low-dose aspirin can cost less than a dollar.换种说法,问问你自己,什么样的医药公司在看到100天的小剂量阿司匹林供应量还值不到一美元时,会对这种能够减少20%癌症死亡几率的药品开价呢?By anyones measure, that is a bargain.不管按照哪一方的标准,这都是一笔非常划算的交易。 点击此处下载本期经济学人讲解PDF与音频字幕 /201303/228078Hey everyone, today on Help Desk, we’re talking about good ways to help pick student loans that are the right fit for you. With me to help us to do that, Stacy Francis and Lynnette Khalfani-Cox. Well, let’s take a listen to this question.大家好,欢迎来到今天的帮助台。今天我们将要讨论一些能够帮助学生挑选适合自己贷款的方法。与我一起完成这一任务的,有 Stacy Francis 和 Lynnette Khalfani-Cox先生。现在,我们来听一听这个问题?Whats the best way to choose my student loans?选择学生贷款的最好方法是什么?So consider who thats coming from, pretty young guy, may be just going into college or in college. You know, hes probably looking at, you know, federal loans versus private.我们得考虑这些可能正要上大学或已在大家的年青人们来自于哪里。你知道,他可能自已正在考虑这些因素,联邦贷款和私人贷款的不同。Right. And beyond the shadow of doubt, he should absolutely look at federal loans first before he even thinks about private student loans. The reason is that federal student loans have lower interest rates, 3.4% right now for the Stafford Loan. They have loan forgiveness options, they have better deferment and forbearance options as well. So, anybody would tell you that you really should go to the federal loan market first. The problem is that a lot of students and their families, they’re behind the eight balls, so to speak, they fill out application there, they get accepted to the college of their choice, they just think I wanna be able to pay for school and theyll just go for private loan immediately.是的。 毫无疑问,在考虑私人学生贷款之前,绝对应当首先考虑联邦贷款。原因是联邦学生贷款的利率较低,斯坦福大学的贷款利率目前为3.4% 。联邦贷款拥有贷款宽恕选项,以及更优惠的延期和延缓还款选项。因此,许多机构会告诉你,你首先应当去联邦贷款市场。问题在于许多学生和他们的家庭,他们处于不利地位,也就是说,他们只填手头有的表格,接受他们所能选择的大学的贷款条件。他们仅仅认为,我(家长)能够付得起学费,他们(孩子们)很快就有能力还款。Yeah.是的。You really should not do that.其实,真的不应该这么做。One of the things I would add my tongue. Look at work-study program as well. I actually did that and at work while I was studying at college. And it helps pay for a good amount of my tuition and also gave me some extra money too. So therere other ways you can think about that, looking at you know other grants in financial. Its amazing the number of grants and opportunities out there. They go on fulfilled that free money sitting there. So loan is not the first thought that should be the last resort.我可以用其中一件事情补充我的看法。也可以利用工作+学习的方法。当我在大学学习的时候,我就边读书打工,它帮我付了相当大一部分学费,而且还让我有余钱可花。还有一些你可以想到的其他办法,比如寻找其他金融助学金之类的。助学金的金额和机会可能会让你大吃一惊。学生一边完成学业,一边享受免费的助学金。因此,贷款应该不是优先选择的,而是万不得已的办法。Very good point. Look at when youre going to school to look at any instant options that are good all states think that is a propensity.非常好的主意。当你要上大学时,除了所有州所倾向性的作法,想一想其他的选择。That’s right.是这样的。We have really good schools. Thank you both. If you got a question you want our experts to tackle, just upload a 30-second with your helpdesk question at iReport.com.我们有许多非常好的学校。谢谢二位。如果你们有问题想让我们的专家帮助解决,请在iReport.com上传30秒的关于你的问题的视频。 201211/210932Where did all the water on the Venus go?金星所有的水去了哪里?And what else lies hidden under her veil?还有什么别的隐藏在她的面纱下吗?In 1989 the space shuttle Atlantis launches the Magellan Probe toward the Venus.在1989年,亚特兰蒂斯号航天飞机向金星发射麦哲伦探测器。After a journey of 15 months Magellan uses radar eyes to peer through the clouds from orbit.在为期15个月的旅行后,麦哲伦探测器使用它的雷达眼从轨道穿过云层。Watching from earth is Allen Stoll fun.从地球上观测是一种乐趣。When you have that you picked up a image and say I wanna the first 3 poeple I wanna 5 people to ever look the piece of ground on another planet .当你想象,你看到一幅图片,说我想首先想要3人,之后是5人在另一个星球上观察其地貌。Its such a sense of awe and a sense of discovery.这是一种敬畏和发现的乐趣。Magellan radar strips away the thick clouds.麦哲伦雷达穿透条状的乌云。For the first time ever we see all the Venus lay bare.有史以来第一次我们看到金星就是这个样子。Welcome to lava land.欢迎来到熔岩土地。There are volcano of all sizes from kilometer across to hundreds kilometers across.这里各种各样的火山从百公里宽度到数千公里宽。The naissance is not that all different from some area on the earth.不是所有的产生都像在地球上的一些地区那样。But on the other hand it is of course a dry world with no vegetation at all.但另一方面,这的确是一个干燥的世界而没有任何植被。Its the sheer number of volcanos that sets Venus apart.这是全然的火山将金星分开。This is the world that has been tortured by fire.好像这是经受过火的折磨的世界。Over 1600 giant volcanos puncture the surface.包含超过1600个巨大的火山穿透表面。Its possible some are still active.很有可能其中的一些仍然活跃。Mark Bolock enjoys spending time on Venus at least the virgin he found马克;布鲁克喜欢花时间在金星上至少他有所发现。 注:听力文本来源于普特201203/174727Science and Technolgy科技Climate change气候变化Good news at last?最终难道是个好消息?The climate may not be as sensitive to carbon dioxide as previously believed气候对二氧化碳的敏感性,可能没有原来认识的那样强CLIMATE science is famouslycomplicated, but one useful number to keep in mind is ;climatesensitivity;. This measures the amount of warming that can eventually beexpected to follow a doubling in the atmospheric concentration of carbondioxide. The Intergovernmental Panel on Climate Change, in its most recentsummary of the science behind its predictions, published in 2007, estimatedthat, in present conditions, a doubling of CO2would cause warming of about 3°C, with uncertainty of about a degree and a halfin either direction. But it also says there is a small probability that thetrue number is much higher. Some recent studies have suggested that it couldbe as high as 10°C.气候科学的复杂是出了名的,但;气候敏感度;是已知的一个非常必须被谨记的指标。这一指标用于衡量由于大气中二氧化碳的浓度增长一倍而引起的温度变化总量。最近一份联合国政府间气候变化专门委员会提交的研究预测报告公布于2007年。该报告预测,按照目前的情况,二氧化碳浓度增加一倍将会导致温度上升3°C,不确定度为±1.5°C。同时报告指出,还存在一种很小可能性,实际的数字也许比这个值要高很多。一些近期的研究认为这个指标高达10°C。If that were true, disaster beckons. But apaper published in this weeks Science,by Andreas Schmittner of Oregon State University, suggests it is not. In DrSchmittners analysis, the climate is less sensitive to carbon dioxide than wasfeared.如果这个情况是可靠的,大限将至。但本周,来自Oregon State University的Andreas Schmittner刊登在《科学》杂志上的一篇论文认为,事实并不是这样的。在Schmittner士的研究中,气候对二氧化碳的敏感性并没有达到大众所担心的水平。Existing studies of climate sensitivitymostly rely on data gathered from weather stations, which go back to roughly1850. Dr Schmittner takes a different approach. His data come from the peak ofthe most recent ice age, between 19,000 and 23,000 years ago. His group is notthe first to use such data (ice cores, fossils, marine sediments and the like)to probe the climates sensitivity to carbon dioxide. But their paper is themost thorough. Previous attempts had considered only small regions of theglobe. He has compiled enough information to makea credible stab at recreating the climate of the entire planet.现有的关于气候敏感性的研究大都依赖于那些回述至19世纪50年代的气象站检测数据。Schmittner士选择了非传统的途径。他的数据来自最近一次冰河期的高峰,一个距今19000年至23000年间的年代。他的团队并非第一个采用这种类型数据(来自冰核,化石,海洋沉积物或其他类似情形)来研究气候对于二氧化碳敏感性的团队。但原先做这种尝试的研究团队仅收集全球很小一部分地区的数据。而Schmittner士编制了足够多的信息以制作一个可以信赖的模型用于预计整个地球的气候变化。The result offers that rarest of things inclimate science-a bit of good news. The groups most likely figure for climatesensitivity is 2.3°C, which is more than half a degree lower than the consensusfigure, with a 66% probability that it lies between 1.7° and 2.6°C. More importantly,these results suggest an upper limit for climate sensitivity of around 3.2°C.其结果为气候科学提供一条珍贵的信息,也许是一条好小心。他的团队倾向于将气候敏感度标定为2.3°C,相比公认的数值降低了超过半度,其数值在66%的保率下介于1.7° C至2.6°C间。更重要的是,气候敏感度的上限应该是3.2°C。Before you take the SUV out for acelebratory spin, though, it is worth bearing in mind that this is only onestudy, and, like all such, it has its flaws. The computer model used is of only middlingsophistication, Dr Schmittner admits. That may be one reason for the narrowrange of his teams results. And although the studys geographical coverage isthe most comprehensive so far for work of this type, there are still blankareas-notably in Australia, Central Asia, South America and the northernPacific Ocean. Moreover, some sceptics complain about the way ancient data ofthis type were used to construct a different but related piece of climatescience: the so-called hockey-stick model, which suggests that temperatureshave risen suddenly since the beginning of the industrial revolution. It willbe interesting to see if such sceptics are willing to be equally scepticalabout ancient data when they support their point of view.当你正为此而兴奋地冲入你的SUV来一次飚车,或者诸如此类的行为,稍等片刻,你的大脑应该想一想,这个理论固然有它的瑕疵。Schmittner士承认,计算机模型的精度仅中等水平。这也许是其团队结果具有的一个局限性。另一个方面,尽管研究的区域覆盖范围在这一领域是最全面的,但仍然存在空白,特别是在澳大利亚,中亚,南美和北太平洋。另外,气候科学界一些对此持怀疑态度的人质疑,所使用的这些年代久远的数据,是一堆一个本质上不同但貌似有关联的片段,一个俗称为的曲棍球模型的现象。他们认为温度在工业革命初期,温度徒然升高。如果这些质疑者使用与怀疑那些年代久远的数据相同眼光审视他们持的观点,这将会是一个非常有趣的现象。 /201210/203210

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