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[经济学人] [2011.10.08]Expanding horizons2011诺贝尔奖:不断扩大的视野

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发表于 2011-10-13 14:31 | 显示全部楼层 |阅读模式
The 2011 Nobel prizes
2011诺贝尔奖


Expanding horizons
不断扩大的视野
This year’s prizes were awarded for work on the immune system, the expansion of the universe and quasicrystals
今年的诺贝尔奖授予免疫系统,宇宙膨胀和准晶体方面的研究发现


THE rules say it is not allowed. But this year a Nobel prize was awarded to a dead man. Ralph Steinman of Rockefeller University in New York, who discovered the role of dendritic cells in activating the immune system, died on September 30th. That news did not, however, make it across the Atlantic Ocean in time, and on October 3rd the Karolinska Institute in Stockholm honoured Dr Steinman with half of this year’s prize in physiology or medicine.
尽管评奖规章并不允许,今年的诺贝尔奖还是被授予一位已故之人——纽约洛克菲勒大学的拉尔夫·斯坦曼。他发现了树状细胞对于激活免疫系统的作用,而他已于9月30号过世。但是,这个消息并没有及时到达大西洋对岸。10月3号,斯德哥尔摩卡罗林斯卡医学院将本届诺贝尔生理学或医学奖的一半授予斯坦曼博士。

The other half went to Bruce Beutler, from the Scripps Institute in San Diego, and Jules Hoffmann, from Strasbourg University, for work on the way the immune system boots up in the face of invading pathogens. Dr Hoffmann found in fruit flies, and Dr Beutler subsequently discovered in mice, a crucial protein-binding mechanism that helps the immune system recognise invaders and trigger an immune response against them.
另一半属于圣地亚哥斯科利普斯研究所的布鲁斯·比尤特勒,和斯特拉斯堡大学的朱尔斯·霍夫曼。因两人对免疫系统在病原体入侵时的开启过程的研究。霍夫曼和比尤特勒先后在果蝇和老鼠身上发现了一种关键的蛋白质组合机制,它能帮助免疫系统识别入侵病毒,并开启对抗这些病毒的免疫应答。

This done, Dr Steinman’s dendritic cells then stimulate some of the immune system’s main cellular troops, known at T-lymphocytes, into action. Some T-cells go on to kill infected body cells. Some act as part of the immune system’s memory, so that it can respond quickly to the recurrence of an infection. And some help regulate the activities of other cells in the immune system.
随后,斯坦曼博士的树状细胞刺激了免疫系统中一些主要细胞群(主要位于淋巴细胞群里)做出反应。一部分淋巴细胞继续杀死感染了病毒的身体细胞,还有一部分转作免疫系统的记忆成分,以便再次感染病毒时迅速作出反应。还有一些细胞帮助调节免疫系统中其他细胞的活动。

Champagne supernovae
香槟色的超新星


The physics prize was awarded for what, in one sense, might reasonably be viewed as the biggest discovery ever made in that subject—that the universe is not only expanding (which had been known since the 1920s), but that the rate of expansion is increasing. Something, in other words, is actively pushing it apart.
获得诺贝尔物理奖的是这样一种发现——宇宙不仅正在扩张(20世纪20年代已经被发现),其扩大的速率也在加快,也就是说,某种未知能量正积极推动着宇宙的分崩离析。从某种意义上来说,它可被看做这一领域最大的发现。

This was worked out by two groups who, in the 1990s, were studying exploding stars called supernovae. One was the Supernova Cosmology Project, led by Saul Perlmutter of the Lawrence Berkeley National Laboratory, in California. The other was the High-z Supernova Search Team, an international collaboration led by Brian Schmidt and involving Adam Riess, both then at Harvard University. It is these three gentlemen who have shared the prize.
这个发现是两个小组于20世纪90年代在研究名叫超级新星的爆炸星体时发现的。一组是由位于加利福尼亚州,劳伦斯伯克利国家天文馆的索尔·波尔马特主持的超新星宇宙学计划,另一组是由当时同在哈弗大学的布莱·史密兹以及亚当·利斯主持的国际合作小组——高红移超新星搜寻队。他们三位同时被授予诺贝尔物理奖。

Supernovae come in various types. One particular sort, though, known as type Ia, always explode with about the same energy and are therefore equally bright. That means it can be estimated, with reasonable precision, how far away they are. In addition, the speed at which an object such as a star or galaxy is moving away from Earth, because of the expansion of the universe, can be worked out from its redshift. This is a fall towards the red end of the spectrum in the frequency of its light. It is caused by the Doppler effect (something similar happens when a police car or fire engine drives past you with its siren blaring, and the pitch of the sound suddenly drops).
超新星以多种不同形式出现。有一种叫做Ia型超新星很特别,它在发生爆炸时总是释放出相同的能量,因此亮度也很大。这就意味着可以合理精确的估算出超新星距地球多远。另外,由于宇宙的扩张,一个星体或是银河系这样的物体在其运动过程中经过地球时的速率能够从其红移中计算出来。就是向物体亮度频率范围的红端下降。这是由多普勒效应引起的(就像是当一辆警车或是消防车经过你的身边,驶向远方时,它们的汽笛声会突然变得幽暗低沉)。

What both groups found was that the light from distant supernovae was fainter than predicted. In other words, the supernovae were farther away than their redshifts indicated they should be, based on the existing model of the universe. Something, then, was pushing space itself apart.
两组研究队发现,从遥远的超新星上发出的光比他们预测的要微弱。换句话说,在现有宇宙模式的基础上,超新星比从它们的红移中得出的距地距离还要遥远。由此可推测有某种神秘的力量在推动宇宙自身的分解。

What that something is, remains conjecture. It has been labelled “dark energy”, but that is really physicists’ shorthand for “we haven’t got a clue”. It may, though, relate to a mathematical term called the cosmological constant that appears in Einstein’s general theory of relativity, and which Einstein thought, before the discovery of the expansion of the universe, was necessary to stop the universe collapsing.
这里的“某种神秘的力量”仍只是个推测。它被取名为“暗能量”,而那实际上是物理学家们对于“我们没有找到答案”的简称而已。但是,“暗能量”可能和一种叫做宇宙学常数的数学术语有关。爱因斯坦相对论中提到了宇宙学常数。在发现宇宙扩大之前,爱因斯坦认为宇宙学常数是阻止宇宙分崩离析的必要物。

Crystal tips
晶体尖端


Unlike the medicine and physics prizes, the chemistry prize went to an individual. The winner was Daniel Shechtman of Technion, a technology institute in Haifa, Israel. On April 8th 1982 Dr Shechtman fired a beam of electrons at a slice of aluminium-manganese alloy, in order to understand its crystal structure. Electrons, being waves as well as particles, produce a diffraction pattern when transmitted through a crystal. Analysis of that pattern can tell you the details of how a crystal’s atoms are arranged. One of the most basic parts of that arrangement, though, is immediately obvious from the picture of spots in the pattern. This is the order of symmetry of the crystal (in other words, the number of ways it can be rotated to produce a pattern identical to the original).
和诺贝尔医学奖和物理学奖不同,诺贝尔化学奖由一个人独享。获奖者是以色列  海法一家技术学院——Technion的达尼埃尔·谢赫特曼。1982年4月8号,谢赫特曼在一片铝锰合金中燃烧一束电子,想观察它的晶体结构。电子和粒子同时产生波动,当电子穿过一块晶体时产生衍射模式。通过对衍射模式的分析可以观察晶体中的原子是如何排列的。其中最本质的一部分可迅速从衍射模式的空间点镇排列图中清楚看到。这就是晶体的对称体的顺序(换句话说,就是使其旋转后能和原型完全重合有多少种方法)。

In this case the order of symmetry Dr Shechtman saw was tenfold. That is impossible. Geometry dictates that only two-, three-, four- and sixfold rotational symmetry can exist. At least, those are the possibilities if the material really is a crystal. What Dr Shechtman had discovered, he realised, was a new sort of material called a quasicrystal. Quasicrystals have regular elements, like normal crystals. But these elements fit together in ways which never properly repeat themselves. The two-dimensional equivalent is known as Penrose tiling (see picture above), after Sir Roger Penrose, the mathematician who put this form of geometry on a formal footing. Penrose tiling has, however, been widely used in the past for decoration, particularly by Islamic artists.
这样一来,谢奇慢博士看到的对称体的顺序就成了10次——那在当时是不可能的。几何学中只存在2,3,4和6次的旋转对称轴存在。至少,如果此物质真的是晶体才有这些可能性。谢奇慢博士意识到,他发现的是一种叫做准晶体的新物种。准晶体和正常的晶体一样,有规则的元素。但是这些元素以一种不重复的方式结合在一起。这个二维等量物被称为彭罗斯瓦片模式(如图),它是以数学家罗杰·彭罗斯的名字命名,他是这类几何学模式的奠基人。但是彭罗斯瓦片模式已经被广泛用在装修当中,特别是伊斯兰艺术家们使用最多。

The discovery of quasicrystals—in effect, three-dimensional Penrose tiles—has revolutionised materials science. Others, with eight- and 12-fold symmetry are now known. They often have interesting properties, such as poor heat conductivity (which makes them good insulators) and low friction (which makes them slippery). This makes them useful for certain sorts of coating. Liquid crystals, often used in display screens, are sometimes quasicrystals, too. And they have even turned up in a type of hard, specialised steel made by Sandvik, a Swedish engineering firm. Alfred Nobel, Sweden’s most famous industrialist, would have been proud.
准晶体的发现——准确的说是三维彭罗斯瓦片模式的发现——是材料学的一场革新。另外,8和12次的对称轴现在也被发现。他们通常有一些有趣的特性,如导热性差(这使之成为优良的绝缘体),摩擦小(这使它们很润滑)。这些性质对一些外套衣料很有用。显示屏中经常使用的一些液体水晶也是准晶体。准晶体甚至能以硬质的特殊钢铁形式出现,瑞士一家工程公司三地维克就制造这种钢铁。阿尔弗莱德·诺贝尔——瑞士最著名的工业家——也将会以此为傲。
Time can both ruin everything and build everything-It depends on you
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