GRE阅读双语材料

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GRE阅读双语材料 科学验证睡眠和月相紧密相关

People do not sleep easy on nights when there is afull Moon.IT SOUNDS like an idea dreamed up over a few beersin the pub one evening.And that, those involved freely admit, is exactly what it was.As Christian Cajochen and his colleagues put it in their paper on the matter in Current biology,We just thought of it after a drink in a local bar one evening at full Moon.It was a way of testing the persistent but unproven idea that the full Moon affects humanbehaviour, generally for the worse.

月圆之夜，不能安眠。这听起来就像某晚在酒吧喝了几杯啤酒后的胡说八道。提出这个观点的人也坦诚的这点子的确就是这么来的。他的同事和Christian Cajochen将有关睡眠与月相研究的论文放到了《当代生物学》上，我们就是月圆的那晚在附近一个酒吧喝了几杯才想到的。这是个未经证实的测试持久性的方法，满月会影响人的行为，总的来说，它将恶化你的行为。

In prescientific days this was expressed in terms like moonstruck and lunatic.And it found even more sinistermanifestation in the form of the lycanthrope, who did not sleep when the Moon was full,but turned into a wolf instead.Though few now believe in werewolves some modern thinkers still suspect the Moon's phaseaffects sleep patterns,and on that particular moonlit night Dr Cajochen and his buddies realised they already had thedata needed to find out.

现代科学出现以前，这种情况被称作月色撩人或者痴狂。研究发现，甚至还有更多像狼人一样的凶神恶煞，他们在月圆之夜化成狼的样子，而不是像往常一般睡去。尽管如今已经很少人相信狼人的存在，但一些当代思想家仍怀疑月相会影响睡眠模式,而且就在这个不同寻常的月夜Cajochen博士和同僚们才意识到，他们早已掌握了本想挖掘的数据。

Those data came from a study on body clocks and sleep patterns they had conducted a decadeearlier at the Centre for Chronobiology at the University of Basel,where they work.Between 2000 and 2003 they had looked at the effect of the daily body clock on the sleeppatterns of 33 volunteers.The protocol they had used was perfect.Volunteers were shut away from daylight for days at a time, so their sleep patterns could notbe affected by the illumination a full Moon brings.And it was also the ultimate in double-blind experiments.

这些数据来自10年前他们所在的瑞士巴塞尔大学时间生物学中心，一个关于生物钟与睡眠研究。那次试验在2000至2003年间曾观察过33名志愿者在日常生物钟下的睡眠模式。研究所使用的方法无懈可击。研究期间，志愿者都与日光隔绝，所以观察对象就不会对满月的月光产生反映。这也是一个终极双盲试验。

Neither the participants nor the organisers could possibly have been biased by knowing theexperiment was intended to look at the effect of the full Moon, since at the time it wasconducted it wasn't.A few days' number-crunching gave Dr Cajochen and his team what they were looking for.And the answer was yes, the phase of the Moon does affect human sleep patterns, even whenthe human involved cannot possibly see the Moon.

志愿者和组织者都不可能因知道此次研究是针对满月带来的效应而出现偏差，当时实验结果没有说明两者之间有关联。经过几天的计算后，Cajochen博士小组得到了他们想要的数据。并得到了肯定的答案，月相的确影响着人们的睡眠，即使参加研究的志愿者不能看到月亮。

Electroencephalography showed that the volunteers slept, on average, 20 minutes less aroundthe time of the full Moon.It also took them five minutes longer to get to sleep, their delta activity was 30% lower thanat other times, their level of melatonin, a sleep-related hormone, was reduced, and theyreported, subjectively, that they had not slept as well as usual.Nor was any of this connected, in female volunteers, with their menstrual cycles.

脑电波图显示了他们的睡眠脑电图，平均来说，将近月圆或者刚过满月那几天，人们睡得比平常少20分钟。而且入睡时间也比平时多需要5分钟，他们的是平日幅度的30%。他们体内的一种与睡眠相关的黑色素荷尔蒙减少，而且研究对象也主观地反映他们不像平常那样睡得香脑波幅度。而女性志愿者的试验数据显示,她们的生理周期与这些睡眠时间和激素水平中的任何一个都没有关系。

Lest any astrologer reading this result get cocky, Dr Cajochen does not believe that what hehas found is directly influenced by the Moon through, say, some tidal effect.What he thinks he has discovered is an additional hand on the body's clock-face.Besides the well-known endogenous daily cycle which the experiment originally studied, there isalso an endogenous monthly cycle entrained to the Moon by unconscious observation over along period of the light from the heavenly bodies concerned.

以免有些占星师洋洋得意，Cajochen博士认为，他所得出的规律并不是由月亮通过某种潮汐导致的。他认为这些研究结果只是往生物钟表盘上多加了一个指针。除众所周知的自身的日循环外，这也是研究最初的目的，身体还有一个受到月亮调控的内在月循环，这是长期以来在对天体不经意的观察中得到的启示。

Lunar cycles exist in other species so this is not, as it were, a lunatic idea.But those species that have been studied are animals like marine iguanas, for whom knowingthe tides is important.What use an ingrained lunar calendar is to a human being remains to be determined.Perhaps sleeping lightly on moonlit nights was a defence mechanism against predators.Wolves, for example.

月亮运转周期对其他物种也影响，这并不是异想天开。被研究的动物对象包括海蜥蜴，潮汐对它来说非常重要。什么使阴历扎根于人类社会当中仍是一个迷。也许在月光明亮的夜晚浅睡是对狼人等肉食动物的防御机制。

GRE阅读材料大补充 海洋生态新视角之塑料星球

关系以及所考察的基本知识点和题目类型几乎没有太大的变化。

SINCE 2008 geologists have been mulling over the idea of the Anthropocene, a proposed newepoch in the history of the Earth that would encompass the years in which people have hadprofound effects on the planet's workings.Most often, discussion of theAnthropocene revolves around how atmospheric chemistry has changed since the beginning ofthe industrial revolution.Sometimes the effects of new terrestrial ecosystems, in the form of fields, pastures andplantations, are also considered.To date, though, how the Anthropocene has created new ecosystems in the oceans as well ason land has not been much examined.

自2008年以来,地质学家一直在研究人类纪这一理念，人类纪是在地球历史上提出的新纪元，其囊括了人们深刻地影响地球的运作的年代。大多数时候,人类纪的讨论大多是围绕着从工业革命开始大气化学有何种变化进行的。有时新型陆地系统所产生的影响也考虑在内。到目前为止,然而人类纪是如何创造新型海洋及陆地生态系统并未做过多的研究。

Such ecosystems are, nevertheless, emerging—as Tracy Mincer of the Woods HoleOceanographic Institution,in Massachusetts, and Linda Amaral-Zettler of the Marine Biological Laboratory, also in WoodsHole, describe in Environmental Science and Technology.The malign effect of floating plastic debris on seabirds, turtles and other sea creatures is wellknown.But, as Dr Mincer and Dr Amaral-Zettler have discovered, plastic debris also provides a newhabitat for organisms small enough to take advantage of it.

不过这样的生态系统在《环境科技》杂志中有所描述，是由马萨诸塞州伍兹霍尔海洋学研究所的特蕾西·明瑟以及伍兹霍尔海洋学研究所海洋生物研究室的琳达阿玛拉尔-特勒联合提出的。众所周知，漂浮的塑料碎片对海鸟海龟以及其他海洋生物有负面影响。但是,正如明瑟及阿玛拉尔-特勒两位博士已经发现的一样，塑料碎片还给有机体提供了一个小型足以充分利用全新的栖息地。

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The two researchers collected pieces of plastic from various sites in the North Atlantic.They then examined each using DNA analysis, and also an electron microscope, to see whatwas living on it.Lots of things were.Altogether, they discovered about 50 species of single-celled plant, animal and bacterial life.Each bit of debris was, in effect, a tiny ecosystem.As with many ecosystems, the bottom of the food chain was occupied by things thatphotosynthesise.These included unicellular algae called diatoms and dinoflagellates, and photosynthetic bacteriaknown as cyanobacteria.

两位研究员从北大西洋的不同地点收集塑料碎片。他们然后用DNA分析仪、电子显微镜检测每一个，观测其上生活着何种生物。有很多生物。总之,他们发现约50种单细胞植物、动物和细菌的踪迹。确切地说，每块碎片是一个小型的生态系统。正如诸多生态系统一样，食物链的底层被光合作用的生物占据着。这些包括名为硅藻和甲藻的单细胞藻类和蓝藻的光合细菌。

Usually, such creatures swim freely in the ocean.They therefore have to work hard to stay near the surface, where light for photosynthesis isabundant.By hitching a ride on a piece of floating plastic, they can stay near the surface without effort.Where plants abound, herbivores will not be far behind.These, Dr Mincer and Dr Amaral-Zettler found in the form of dinoflagellates,some of which liketo snack on smaller creatures to supplement their photosynthesis.They also found predators on the herbivores, in the form of ciliates and predator bacteria,which feed on other bacteria.

通常,这些生物在海洋里自由自在地游荡。因此他们必须努力保持在表层水域，因为那里的进行光进行光合所需的阳光是充裕的。通过搭乘漂浮塑料这一顺风车,他们可以毫不费力地呆在表层。植物比比皆是的地方食草动物的出现也不会落后。明瑟及阿玛拉尔-特勒两位博士以甲藻的形式发现了食草动物的存在,一些甲藻喜欢吃小型生物作为他们光合作用的补充。他们还发现食草动物的捕食者，如纤毛虫以及以其他细菌为食的捕食细菌。

Except for top predators—the type that themselves prey on predators—the two researchersthus discovered a classic web of food chains of the sort familiar from ecology text books.And they also, and perhaps most pertinently from the human point of view, found evidence forone other part of such a food web: the decomposers.Plastics are energy-rich substances, which is why many of them burn so readily.Any organism that could unlock and use that energy would do well in the Anthropocene.Terrestrial bacteria and fungi which can manage this trick are already familiar to experts in thefield.

除了顶级捕食者外，两位研究人员发现了一个与生态学课本上相似的经典的食物网。或许从人类的观点来看最为适切的他们还发现了食物网的另一部分：分解者。塑料是能源丰富的物质,这就是为什么他们中的许多容易燃烧的原因。任何可以分解和使用那些能源的生物在人类纪将会取得先机。掌握这种技能的陆地上的细菌及真菌是这个领域的专家。

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Dr Mincer and Dr Amaral-Zettler found evidence of them on their marine plastic, too.They noticed many of their pieces of debris sported surface pits around two microns across.Such pits are about the size of a bacterial cell. Closer examination showed that some of thesepits did, indeed, contain bacteria,and that in several cases these bacteria were dividing and thus, by the perverse arithmetic ofbiological terminology, multiplying.Though the two researchers have not yet proved the bugs in the pits are actually eating theplastic, that hypothesis seems a good bet.And if they are, it suggests plastic pollution in the ocean may not hang around as long as hasoften been feared.

明瑟及阿玛拉尔-特勒两位博士在海洋塑料上也发现了它们的踪迹。他们发现很多塑料碎片的运动表面周围有大约两微米的凹坑。凹坑与细菌一般大小。进一步的研究显示这些凹坑中的一部分确实含有细菌，在部分状况下细菌正在分裂，因此根据生物学的反常计算其数量正在递增。尽管两位研究员至今未找到凹坑中的细菌是以塑料为食的证据，那个假说就好像是一场赌博。如果假说是正确的，这就意味着海洋塑料污染可能不如担心的那么持久。

Less encouragingly, Dr Mincer and Dr Amaral-Zettler also found cholera-like bacteria in theirtiny floating ecosystems.Both fish and seabirds act as vectors for cholera,so anywhere that such creatures might pick upcholera bugs is something worth keeping an eye on.The researchers paint an intriguing picture of the adaptability of nature, and provide anotherpiece of the jigsaw that is the Anthropocene.Conservationists intent on preserving charismatic megafauna have reason to lament thespread of plastics through the ocean.But those interested in smaller critters have been given a whole, new sphere—theplastisphere—to study.

令人扫兴的是，明瑟及阿玛拉尔-特勒两位博士在漂浮的小型生态系统中发现了类似于霍乱的细菌。鱼类或者是海鸟都充当着霍乱病菌的载体，所以任何使这些生物可能携带霍乱病菌的地区都值得密切关注。研究者就大自然的适应性描绘了一幅耐人寻味的画面，并提供了人类纪的另一块拼图。致力于保护引人好奇的大型动物的环保人士有理由担心海洋塑料污染的蔓延。但是却给了那些对小型生物感兴趣的环保人士一个全新的视角——塑料星球。

不要自己吓自己 要相信自己的身体很棒

You can. But it helps to think well of yourself in the first place.THE link between mind and body is terrain into which many medical researchers, fearing ridicule, dare not tread.But perhaps more should do so.For centuries, doctors have recognised the placebo effect, in which the illusion of treatment, such as pills without an active ingredient, produces real medical benefits.

你可以拥有很好的体魄。但首先，你要自我感觉好，这会有帮助的。许多医学研究者都不敢探究躯体和心理的关系，因为他们害怕，踏进这一领域会受人嘲笑。但也许，研究这方面的人应该多一些才好。几个世纪以来，医生已逐渐认可了安慰剂效应。因为患者会产生错觉，认为自己在接受治疗。比如，服用无活性成分的药片也能产生实际疗效。

More recently, respectable research has demonstrated that those who frequently experience positive emotions live longer and healthier lives.They have fewer heart attacks, for example, and fewer colds too.Why this happens, though, is only slowly becoming understood.What is needed is an experiment that points out specific and measurable ways in which such emotions alter an individual's biology.

根据最近的可靠的研究表明，平时积极乐观的人会活得更长久、更健康。比如，他们心脏病发作的次数更少，也很少感冒。然而，人们才开始慢慢了解这种情况发生的原因。人们需要的是做一场实验，明确这样的情绪是通过怎样具体的、可测量的方式来改变人的生理状况。

And a study published in Psychological Science, by Barbara Fredrickson and Bethany Kok at the University of North Carolina at Chapel Hill, does precisely that.Dr Fredrickson and Dr Kok concentrated their attentions on the vagus nerve. This nerve starts in the brain and runs, via numerous branches, to several thoracic and abdominal organs including the heart.Among its jobs is to send signals telling that organ to slow down during moments of calm and safety.

北卡罗来纳大学教堂山分校的芭芭拉·弗雷德里克松和贝瑟尼·可可就是按照这个思路做了一项研究，并在《心理科学》上发表了相关论文。弗雷德里克松博士和可可博士把注意力集中在迷走神经上。这对神经起于颅腔，通过无数分支与胸腔、腹腔的几个脏器相连。它的其中一项工作就是为器官发送信号，让它们在躯体平静、安宁的状态下放缓节奏。

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How effectively the vagus nerve is working can be tracked by monitoring someone's heart rate as he breathes in and out.Healthy vagal function is reflected in a subtle increase in heart rate while breathing in and a subtle decrease while breathing out.The difference yields an index of vagal tone, and the value of this index is known to be connected with health.Low values are, for example, linked to inflammation and heart attacks.

他们通过监测一个人吸气、呼气时的心率，追踪记录迷走神经如何有效地工作。如果吸气时心率略微增加，呼气时略微下降，则说明迷走神经工作正常。两次心率之差构成迷走神经张力指数。人们都知道该指数与健康程度有关。 例如，低指数就与炎症、心脏病发作几率有联系。

What particularly interested Dr Fredrickson and Dr Kok was recent work that showed something else about the vagal-tone index: people with high tone are better than those with low at stopping bad feelings getting overblown.They also show more positive emotions in general.This may provide the missing link between emotional well-being and physical health.

让弗雷德里克松博士和可可博士特别感兴趣的是最近的研究，因为它显示了迷走神经张力指数的另一个性质：与张力指数低的人相比，指数高的人能更好地防止不良情绪失控。研究也显示，指数高的人大体上情绪更乐观。这也许弥补了心理健康与生理健康之间缺失的环节。

In particular, the two researchers found, during a preliminary study they carried out in 2010, that the vagal-tone values of those who experience positive emotions over a period of time go up.This left them wondering whether positive emotions and vagal tone drive one another in a virtuous spiral.They therefore conducted an experiment on 65 of the university's staff, to try to find out.

尤其值得注意的是，两位研究人员在2010年的初步探究中发现，人们如果体验一段时间的积极情绪，迷走神经张力指数会就增加。这为他们留下了疑念，积极情绪与迷走神经张力是否处于一个良性循环之中，互相促进?因此，他们对本校的65名员工展开实验，一探究竟。

They measured all of their volunteers' vagal tones at the beginning of the experiment and at its conclusion nine weeks later.In between, the volunteers were asked to go each evening to a website especially designed for the purpose, and rate their most powerful emotional experiences that day.Dr Fredrickson and Dr Kok asked their volunteers to consider nine positive emotions, such as hope, joy and love, and 11 negative ones, including anger, boredom and disgust.

他们在实验开始时测量了所有志愿者的迷走神经张力指数，九周后实验结束时又再次测量。在实验期间，他们要求志愿者每天晚上登录一家专门为此设计的网站，为当天所经历的各种最强烈情绪评定等级。弗雷德里克松博士和可可博士为志愿者提供了九种可供考虑的积极情绪选项，如期待、开心、热爱，还有十一种消极情绪，包括愤怒、疲倦、厌恶。

They were asked to rate, on a five-point scale, whether—and how strongly—they had felt each emotion.One point meant not at all; five meant extremely.In addition, half the participants, chosen at random, were invited to a series of workshops run by a licensed therapist, to learn a meditation technique intended to engender in the meditator a feeling of goodwill towards both himself and others.

两位博士要求他们以五分制一一打分：是否有这样的情绪、情绪有多强烈。1分代表完全没有，5分代表非常强烈。此外，他们还随机邀请了一半志愿者到一个注册治疗师开的一系列工作坊中，学习冥想的技巧，旨在让冥想者产生一种善待自己、善待他人的情绪。

This group was encouraged to meditate daily, and to report the time they spent doing so.Dr Fredrickson and Dr Kok discovered that vagal tone increased significantly in people who meditated, and hardly at all in those who did not.Among meditators, those who started the experiment with the highest vagal-tone scores reported the biggest increases in positive emotions.

在众多冥想者之中他们鼓励这组人每天冥想，并向他们报告冥想用的时间。弗雷德里克松博士和可可博士发现，冥想的人的迷走神经张力显著增加，而那些不冥想的人几乎没有任何变化。，那些实验一开始就拥有最高指数的人，积极情绪增加的幅度最大;

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Meditators who started with particularly low scores showed virtually no such boost.Taken as a whole, these findings suggest high vagal tone makes it easier to generate positive emotions and that this, in turn, drives vagal tone still higher.That is both literally and metaphorically a positive feedback loop.Which is good news for the emotionally positive, but bad for the emotionally negative, for it implies that those who most need a psychosomatic boost are incapable of generating one.

而一开始指数就很低的人，几乎没有这样的奇效。作为一个整体来看，这些发现意味着，这迷走神经张力指数越高，越容易产生积极情绪;反过来，积极情绪又能促进指数的提升。无论是从直观还是隐含的角度看，这都是一个正反馈循环。对于情绪乐观的人来说，这是个好消息;但对于消极的人来说，情况正好相反，因为它意味着，那些最需要振作精神的人却往往无法产生积极情绪。

A further experiment by Dr Kok suggests, however, that the grumpy need not give up all hope.A simpler procedure than meditation, namely reflecting at night on the day's social connections, did seem to cause some improvement to their vagal tone.This might allow even those with a negative outlook on life to bootstrap their way to a mental state from which they could then advance to the more powerful technique of meditation.

然而可可博士的进一步研究表明，脾气不好的人也尚存希望。有一种比冥想简单的方法，即每天晚上对白天的社交活动进行反思，似乎能在一定程度上提高迷走神经张力指数。就算是对生活不抱希望的人，也可能通过这种方式自我解脱，达到另一种精神状态，然后他们可以进一步使用效果更好的冥想技巧。

Whether, besides improving general health, the mechanism Dr Fredrickson and Dr Kok have discovered helps explain the placebo effect remains to be investigated.But it might, because part of that effect seems to be the good feeling engendered by the fact of being treated.More generally, doctors in the ancient world had a saying: a healthy mind in a healthy body.This sort of work suggests that though this proverb is true, a better one might be, a healthy mind for a healthy body.

除了提高综合健康水平，弗雷德里克松博士和可可博士发现的机制是否有助于解释安慰剂效应，还有待进一步研究。但这的确有可能，因为安慰剂效应就包括实验中因治疗产生的良好情绪。更为普遍的是，古代的医生就有个说法：身体好，精气儿足。而这个实验则启发人们，尽管谚语说得有理，但精气儿足，身体好可能才更准确。

你知道吗?鸟类拥有磁性感知能力

候，要多看各类教课书籍和充分的课外读物。长此以往，才能在保证阅读速度的同时降低扣分率。

Birds can navigate by the Earth's magnetic field.How they do it is still a mystery.Where would people be without magnetic compasses?The short answer is: lost.By giving human beings a sixth sense—an ability to detect the hitherto invisible magneticfield of the Earth—the compass proved one of the most important inventions ever.

鸟类能够利用地球磁场导航。机理尚不明确人类没有指南针会怎样?很简单：迷失方向。指南针给了人类第6感，使人能辨别地球无形的磁场，成为最重要的发明之一。

It let sailors navigate without sight of the night sky.And that led to the voyages of discovery, trade and conquest which created the politicalgeography of the modern world.Imagine, then, what animals which had their own, built-in compasses could achieve.They might spend their summers doingthe English Season in Glyndebourne or Henley, and then overwinter in the warmth of Mombasa. They might strike out, like intrepid pioneers, from Angola to Anchorage.They might even, if truly gripped by wanderlust and a hatred of the darkness, live in near-perpetual daylight by migrating from Pole to Pole.And that is just what some birds do.

海员不用观察夜空便可以辨识方向。人们用它进行海上探索，海上交易，攻城掠地，进而开创了现代世界的政治版图。有些动物有自己内嵌的指南系统。可以想象得出这些动物的能力。它们可以在戈林德伯恩或亨利镇消暑，享受自己的英格兰夏日。然后在温暖的蒙巴萨岛过冬。它们可以像无畏的开拓者一样，从安哥拉独闯安克雷奇。假如它们为旅行所牵绊，为黑暗而烦恼，它们会穿梭于两极之间，过着永远有光亮的生活。以上这些只是鸟类能力的一部分。

Swallows travel between Europe and Africa. Northern wheatears fly from Africa to Alaska, andback.Arctic terns each year make the journey from one end of the planet to the other.And they can do it, at least in part, because they do have a magnetic sense denied tohumans.

家燕在欧洲和非洲之间迁徙。石栖鸟在非洲和阿拉斯加之间迁徙。每年，北极燕鸥都会从地球的一端飞到另一端。它们能这么做的原因之一便是鸟类可以感知磁性，而人类不行。

The most familiar avian navigation trick is that pulled off by homing pigeons.As a consequence pigeons have often found themselves at the sharp end of investigationsabout how bird navigation in general, and magnetic sense in particular, actually work.That pigeons have such a sense was shown more than 40 years ago, by William Keeton ofCornell University, in upstate New York, who attached magnets to pigeons to see if they couldstill home.They could not, though birds fitted with non-magnetic dummies managed perfectly well.

人类最为熟知的鸟类导航技巧就是通过研究信鸽而得到的。鸽子便处在了人类研究的尖端。人们用它研究鸟类整体的导航机能，用它特别研究磁性感应机制。鸽子显示出此种能力是在40年前。当时，纽约州北部康乃尔大学的William Keeton把磁体系在鸽子身上，观察它们是否能够回家。结果是它们不能，但是那些带有仿磁体的鸽子却回家。

Since then, experiments on other species have shown magnetic sensitivity is common amongbirds. What these experiments have not shown, however, is how the birds manage it.See it? Hear it? Smell it?There are two theories.One is that the magnetic sensors are grains of magnetite, a form of iron oxide which, as itsname suggests, is easily magnetised.The other is that the Earth's magnetic field affects a particular chemical reaction in the retinain a way that reaches into the arcane depths of quantum mechanics.

此后的实验表明，磁性感知能力是鸟类共有的，但并没有解释是如何操作的。视觉?听觉?嗅觉?理论上的说法有两种。一种是鸽子具有磁感应器，这是一种以氧化铁形式存在的磁铁矿粒子。顾名思义，这种物质极易磁化。另一种说法认为，地球磁场能对视网膜里特定的化学反映产生影响，在某种程序上可以达到神秘量子力学的深度。

The magnetite hypothesis concentrates on birds' beaks.Magnetite grains are common in living things, and are known to be involved in magneticsensing in bacteria. In birds they are particularly abundant in the beak.So last year David Keays of the Institute of Molecular Pathology, in Vienna, dissected the beaksof nearly 200 unfortunate pigeons, to find out more.What he discovered was not encouraging.There were, indeed, lots of magnetite grains.But he had expected they would congregate in some sort of specialised sensory cell akin to thetaste buds of the tongue or the hair cells of the ear.Instead, he found that the beak's magnetite is mostly in macrophages.

These are cells whose job is to wander around amoeba-like, chewing up bacteria and debrisfrom other body cells as they go.

磁铁矿假说的焦点是鸟类的喙。磁铁矿粒子是生物共有的，广泛存在于鸟的喙中。去年，维也纳分子病理学研究所的David Keays对将近200只鸽子进行了解剖，以期得到更多发现。但是，他发现的并不令人鼓舞。大量铁磁矿粒子确实存在。他原以为铁磁矿粒子会聚集成为专门的感觉细胞，类似于舌头上的味蕾和内耳毛细胞。但是，他发现，喙部的铁磁矿主要以巨噬细胞的形式存在，这些细胞的职能是以游离细胞的形式对细胞残片及病原体进行噬菌。

Not, then, likely candidates as magnetic sensors.Other experiments, though, do suggest the beak is involved.The nerve that connects it to the brain is known as the trigeminal.When Dominik Heyers and Henrik Mouritsen of Oldenburg University, in Germany, cut thetrigeminals of reed warblers the birds' ability to detect which way was north remained intact.They did, however, lose their sense of magnetic dip.Dip indicates latitude, another important part of navigation.To confuse matters further, some people accept Dr Keays's interpretation of what is going onin the beak,but think that the relevant magnetite grains are elsewhere—in the hair cells of the ear, whichare also rich in iron oxide.If they are right, then from the birds' point of view they are probably hearing the magneticsignal.The main alternative to the nasal-magnetite hypothesis, though, is not that birds hearmagnetic fields, but that they see them.

因此，巨噬细胞不可能具有磁感应功能。其它的实验也包含了对喙的研究。联结喙与脑的神经叫三叉神经。德国奥尔登堡大学的Dominik Heyers和Henrik Mouritsena切断了苇莺的三叉神经，保留了它们辨别北方的能力。然而，这些鸟却失掉了磁倾角的感应力。磁倾角可以指示纬度，是导航的重要组成部分。Keays对鸟喙解释使情况更加复杂。但有些人还是接受了他的说法。但是这些人认为鸟身体的其它部位也存在磁铁矿粒子—内耳毛细胞。氧化铁也富含这种粒子。假如这些人的假定正确，从鸟的角度来看，它们可能听得到磁信号。鼻腔内存在磁铁矿的假说 并不是鸟类可以听到磁场，而是能看到磁场。

One line of evidence for this is that part of a bird's brain, called cluster N, which gets its inputdirectly from the eyes, seems to be involved in magnetic sensing.Experiments Dr Mouritsen's team conducted on robins showed that destroying cluster Ndestroys a bird's north-detecting sense, and other experiments, on meadow pipits, show thatcells in cluster N are far more active when the birds are using their magnetic sense than whenthey are not.

关于此的证明是，鸟大脑中有一部分叫cluster N，可以直接得到眼部输送的信息，好像跟磁场感应有联系。博士Mouritsen研究团队对知更鸟进行了实验，得出推断。实验显示破坏知更鸟的cluster N，也就破坏了它们识别北方的能力。研究团队又对草地鹨进行了实验。实验显示，鸟类使用磁感应能力的时候，cluster N细胞异常活跃。

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The problem with this idea is that birds' eyes do not have magnetite in them.If they do house magnetism detectors, those detectors must be something else.That something, according to a hypothesis advanced by Klaus Schulten, who works at theUniversity of Illinois at Urbana-Champaign, is a type of retinal protein called a cryptochrome.When hit by light, a cryptochrome produces pairs of molecules called free radicals that areelectrically neutral but have unpaired electrons in them.Electrons are tiny magnets, so they tend to attract each other and pair up in a way thatneutralises their joint magnetic fields.

此种假说的问题在于鸟类的眼部没有磁铁矿。假如它们真的起到了磁探测器的作用，那么肯定另有他物。在伊利诺斯大学香槟分校工作。据Schulten，这种他物是一种名为cryptochrome的尿视黄醇蛋白。当受到光照时，就产生名为自由基的分子对。这种自由基呈电中性，其中含有未配对电子。电子就是微小的磁性体。因此，当它们的联合磁场中合之时，电子就会相互吸引，就会形成组对。

Unpaired electrons, however, remain magnetic, and thus sensitive to the Earth's field.Moreover, because the unpaired electrons in the free radicals were originally paired in themolecule that split to form the radicals, quantum mechanics dictates that these electronsremain entangled.This means that however far apart they move, what happens to one affects the other'sbehaviour.

但是，那些不成对电子仍具磁性，对地球磁场很敏感。因为自由基中的那些不成对电子最初存在于分裂成为自由基分子之中，量子力学规定这些电子依然是绞缠的。也就是说，无论双方离得有多远，一方的行为会影响另一方。

Calculations suggest the different ways the two radicals feel the Earth's field as they separateis enough to change the way they will react with other chemicals—including ones that triggernerve impulses, and that, via entanglement, they can transmit this information to each other,and thus affect each other's reactions.

此种假设表明，当两种自由基分离时，它们感知地球磁场的相反作用足够能够改变它们与其它化学物质相互反应的方式――包括那些能产生神经脉冲的化学物质。同时，通过绞缠，它们彼此能互相信息，从而产生相互影响。

This, the calculations indicate, would be enough for a bird's brain to interpret the magneticfield.It would probably see a pattern of spots before its eyes, which would remain stationary as itscanned its head from side to side.And some birds do, indeed, scan their heads this way when assessing the direction ofmagnetic north.It is possible, of course, that both hypotheses are right, and that birds have two magneticsenses, with one perhaps concentrated on north detection and the other on detecting dip.But there is something particularly poetic about the idea that even part of this mysterioussixth sense depends on a still-more-mysterious quantum effect—one that Einstein himselfdescribed as spooky action at a distance.

此种假设表明，这足可以让鸟脑识别磁场。鸟眼可能会看到眼前有某种样式的斑点图案，当鸟类对其识别之时，眼睛是固定的。其实，当鸟类辨别地磁北极之时，确实能够用此法扫描头部。当然，两种假说都有正确的可能。鸟类也有可能有两套磁感应能力，一种集中在北方，另一种集中于磁倾角。这种神秘的第六感觉依赖于更加神秘的量子力学效应。对此还有一种诗意般的解释，即爱因斯坦自己说的鬼魅般的超距作用。

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