Volume 440 Number 7087 pp969-1088 封面故事：核电站安全及核能前景问题
1986年4月28日，前苏联承认，位于乌克兰的切尔诺贝利核电站两天之前发生了一起事故。从那时起，全世界核电站的管理规范已经发生了变化。在本期的一系列文章中，我们从人类生命和疾病以及生态破坏等角度对切尔诺贝利核电站事故的代价进行了分析。20年已经过去了，现在也是评估21世纪核能前景的时候了。
伴护分子Hsp90二聚物的结构
伴护分子Hsp90激发很多致癌蛋白，这些蛋白发生突变或失去控制会诱发癌症。该分子依赖于ATP，对ATP结合的抑制会阻断对致癌基因的激发。所有这些使得Hsp90成为合理化疗的一个首要目标。然而，我们对该分子的生化特点了解很少，关于它利用ATP的手段也存在争议。现在，Ali等人确定了 Hsp90二聚物的结构，这个二聚物存在于由ATP和一个“共伴护分子”形成的复合物中。从该结构可以看出与ATP结合在一起的伴护分子周期是怎样工作的，以及它是怎样在依赖于Hsp90的“客户”蛋白中促成构象变化的。
星光来自哪里？
弥漫于星际空间的扩散光含有关于早期宇宙的宝贵信息。但到底是什么信息却是一个猜测的问题：它是来自在早期宇宙中最先形成的恒星的光线，还是由后来产生的星系直接发出的星光？利用HESS（建在纳米比亚的“高能立体系统”阵列）对两个遥远的活动星系所做的伽马射线观测显示，扩散光强度比根据最近研究的结果所预计的要低。这说明，宇宙对伽马射线比我们所想的更透明，星系更可能是主要光源，而不是早期恒星。
直接测定纠缠态的新方法
量子纠缠，指的是物体在空间上是分开的、但却共享一个量子态的现象。它是量子信息应用的一个至关重要的资源，也可以说是经典世界与量子世界最让人惊异的区别。研究人员在关于纠缠的数学描述方面和关于纠缠态的生成方面都取得了引人注目的进展，但对纠缠态在实验上的准备程度进行定量仍然极为困难。所以，本期 Nature报告的一个新的直接测定纠缠的方法可以说是一项重要进展。该方法在一个相对比较简单的线性光学体系中用一个步骤来测定光子的双向纠缠。
气候敏感度的新上限
未来任何全球变暖的尺度都将取决于气候系统对温室气体浓度变化的敏感度。过去的气候可以成为预测未来事件的有用指南，现在，根据对在1280-1850年这一前工业化时期北半球气温的重建结果对气候敏感度所做的一个新的估计，为我们提供了比以前更为精确的指南。过去人们认为，气候敏感度（由于大气中CO2 浓度加倍所造成的全球平均气温变化）的上限在7.7?C 和 9?C之间，但新模型表明，气候敏感度超过6.2?C的概率非常小。
隐藏在南极冰川下的神秘世界
一个由超过140个湖泊组成的隐藏在冰川下的世界存在于南极的冰层下面。过去，人们普遍假设，这些湖泊是一个静态生态系统，彼此之间以及与外界都几乎是隔绝的，驻留时间长，循环缓慢。但根据对该地区地表高程变化所做的一项为期16个月的研究，事实远不是这样。研究人员探测到了迅速的排放现象，整个冰川下流域有可能被定期冲刷。
新化石证据表明蛇起源于陆地
想到蛇，我们脑子里就会想到一种没有四肢的爬行动物。但蛇过去并不总是这样。我们已经知道化石中的一些蛇是有四肢的，有足够多的化石证据可以证明，蛇的四肢的消失不是一个简单的、渐进的过程。从阿根廷白垩纪地层中新发现的一个蛇化石不仅有强壮的后腿，而且还有一个荐骨区域（过去在蛇身上从未见过）,它使得后腿能够与脊椎骨通过关节连接起来。这可能是已知最原始的蛇，其解剖特征表明，蛇起源于陆地上，是穴居的，而不是像人们经常以为的那样起源于海洋。
验证博弈理论的新模型
解释合作的演化是演化生物学家所面临的最棘手的问题之一。利用博弈理论模拟相互作用已经有所收获，但该方法经常受到可能的策略数量较少的限制。现在出现了一种新方法，它采用的是一个计算机模型，从而扩大了可能的策略的范围。这一方法应能够对该理论进行更为严格的验证。这一模型真正放开了对“选手们”的约束，想象中的生物甚至可以在博弈过程中自己制定自己的规则。所获得的结果是一个由合作行为构成的一个丰富的生态系统，以前从未在这样的模拟中看到过。在这个生态系统中，传统博弈理论的“老鹰”和“鸽子”中又加入了乐于合作的“八哥”和“乌鸦”。
同一形态特征的重复演化
同一形态特征的重复演化是一个常见现象。它使人们想到这样一个问题：演化是否仅限于走某些路径？或者说对同一个表现型是否有很多遗传路径？对果蝇求偶过程中所显示的雄性翅膀着色图案所做的一项研究表明，类似的图案形成方式至少独立出现过两次，而在亲缘关系很近的果蝇品种中至少丢失过5次。所有这些事件涉及黄色着色基因上调控方面的变化，但翅膀斑点的两次独立出现来自不同调控元素的同时选择。演化在该基因上进行了两次，但每次采用的路径不同。
神经脉冲的产生方式
大脑中的神经元通过只有一个伏特若干分之一的电子脉冲或动作电位来进行通信，这种脉冲持续时间只有1秒的千分之一。1952年，Alan Hodgkin 和Andrew Huxley因其关于动作电位产生的理论而共同获得诺贝尔奖，他们的理论是根据对乌贼巨轴突的研究工作发展来的。此后，人们一直默认神经脉冲在从蛞蝓到人类在内的所有动物中都基本是以同样方式产生的。现在，对高等动物皮层神经元中的动作电位所做的一项研究表明，这种假设需要修正。皮层动作电位启动的关键特征与Hodgkin–Huxley理论的预测是偏离的，因为这些神经元比以前所假设的更适合进行快速信息处理。
个性化用药有可能实现
我们将来有一天可能会受益于“个性化药物”，制造这种药物需要对一个人的关键特征进行分析，预测哪些药物对该患者会有效。“药物代谢经济学” （Pharmaco-metabonomics）是一种新的定制方法，它将药物施用前代谢物分析与化学计量结合起来，模拟和预测某一个具体的患者所产生的反应。本期Nature发表了对该方法的一项验证研究，研究人员以对大鼠施用乙酰氨基酚（Paracetamol）作为研究模型。该验证试验成功地预测出了尿药物代谢物的一些特征以及药物施用前尿组成与施用后肝损伤程度之间的一个联系。因为该方法涉及对一个患者代谢表现型（代谢表现型不仅受基因型的影响，而且受营养状态、年龄和疾病等环境因素的影响）的分析，所以它可能是实现人类个性化医疗保健的一个重要步骤。
利用数学模型设计合成酶的新方法
自然分子演化产生了专门催化单一化学反应的酶，因为过去选择性很差的酶在这个过程中被改变了。Yoshikuni等人现在开发出一种利用一个数学模型设计合成酶的方法，该数学模型能模仿分子演化的机制。他们利用这一系统生成了一系列新颖的“倍半萜烯环化酶”，这些酶利用不同反应路径生成不同最终产物。这个结果显示了利用一种酶“脚手架”来生成现有分子更纯净版本、或生成自然界不存在的潜在新分子的可行性。
ContentsEditorials
Learning from Chernobyl p969
As the accident that blackened the name of nuclear power fades from memory, openings present themselves for the technology to edge its way back into public favour.
doi:10.1038/440969a
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Drugs tests on trial p970
Britain's clinical-trial regulator has no good options.
doi:10.1038/440970a
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Mentoring award 2006 p970
doi:10.1038/440970b
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Research Highlights
Research highlights p972
doi:10.1038/440972a
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News
Societies spurn women editors p974
Resignation spotlights sex discrimination.
Rex Dalton
doi:10.1038/440974a
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Glint from tenth planet dazzles astronomers p974
Pluto's neighbour seems strangely shiny.
Jim Giles
doi:10.1038/440974b
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Sidelines p975
doi:10.1038/440975a
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Lakes linked beneath Antarctic ice p977
Massive flows of water change perceptions of frozen continent.
Jim Giles
doi:10.1038/440977a
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See also: Editor's summary
Wanted: cancer boss p978
The White House is looking for a new head for the National Cancer Institute. What kind of person does it take to run a $4.8-billion research powerhouse? Nature asked some top cancer researchers for their thoughts.
doi:10.1038/440978a
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News in brief p980
doi:10.1038/440980a
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News
Special Report: Counting the dead p982
Twenty years after the worst nuclear accident in history, arguments over the death toll of Chernobyl are as politically charged as ever, reports Mark Peplow.
doi:10.1038/440982a
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News Features
Nuclear power: Chernobyl and the future: when the price is right p984
Once touted as too cheap to meter, nuclear power has become too costly to build. But the economics may be shifting, finds Jim Giles.
doi:10.1038/440984a
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Nuclear waste: Chernobyl and the future: Forward planning p987
The global future of nuclear power may rest in large part on local politics, reports Geoff Brumfiel.
doi:10.1038/440987a
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Business
Handle with care p990
China's drug market is booming, and will soon be the fifth largest in the world. But despite this potential, global companies are being advised to approach the country with caution, as Colin Macilwain reports.
doi:10.1038/440990a
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In brief p991
doi:10.1038/440991a
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Market watch p991
Meredith Wadman
doi:10.1038/440991b
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Correspondence
Ethics of using employees' eggs in cloning research p992
Susan Hawes and Justin Oakley
doi:10.1038/440992a
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Ethics: China already has clear stem-cell guidelines p992
Linzhao Cheng, Ren-Zong Qiu, Hongkui Deng, Yu Alex Zhang, Ying Jin and Lingsong Li
doi:10.1038/440992b
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Eastern European science needs sweeping changes p992
Witold F. Palosz
doi:10.1038/440992c
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Reviewers peering from under a pile of 'omics' data p992
Jeremy K. Nicholson
doi:10.1038/440992d
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Commentary
Chernobyl and the future: Too soon for a final diagnosis p993
Twenty years ago, the nuclear accident at Chernobyl exposed hundreds of thousands of people to radioactive fallout. We still have much to learn about its consequences, argue Dillwyn Williams and Keith Baverstock.
doi:10.1038/440993a
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Books and Arts
Hollow centre p995
Nanotechnology is a discipline in the throes of an existential crisis.
Richard A. L. Jones reviews The Dance of Molecules: How Nanotechnology is Changing our Lives by Ted Sargent
doi:10.1038/440995a
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Looking for clues p996
Anthony Busuttil reviews Murderous Methods: Using Forensic Science to Solve Lethal Crimes by Mark Benecke
doi:10.1038/440996a
Full Text | PDF (159K)
Turning to fraud p996
Jennifer Rohn reviews Intuition by Allegra Goodman
doi:10.1038/440996b
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Science in culture: The zenith of Islamic science p997
An exhibition in Britain explores a rich scientific heritage.
Philip Ball
doi:10.1038/440997a
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News and Views
Neuroscience: Spikes too kinky in the cortex? p999
The Hodgkin–Huxley theory that explains the mechanism of how neurons fire forms the cornerstone of computational neuroscience. But something it hasn't predicted is happening in the brain cortex.
Boris Gutkin and G. Bard Ermentrout
doi:10.1038/440999a
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Glaciology: Ice-sheet plumbing in Antarctica p1000
It's not easy to work out what is going on beneath four kilometres of ice. But remote imaging has enabled the discovery of the long-distance discharge of water from one subglacial lake to another in Antarctica.
Garry K. C. Clarke
doi:10.1038/4401000a
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Evolution: Spot on (and off) p1001
The repeated appearance and loss of a spot on the wings of fruitflies during their evolution is caused by mutations in one gene. This finding provides an unprecedented window on the genetics of convergent evolution.
Gregory A. Wray
doi:10.1038/4401001a
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Astronomy: Trouble at first light p1002
The question of how much light the first stars produced is fundamental to models of the Universe's development. But observations have so far failed to agree: is the answer a lot, or not very much at all?
Piero Madau
doi:10.1038/4401002a
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Brief Communications
Biomechanics: A pneumo-hydrostatic skeleton in land crabs p1005
A sophisticated dual support system enables a crab to stay mobile immediately after moulting.
Jennifer R. A. Taylor and William M. Kier
doi:10.1038/4401005a
First paragraph | Full Text | PDF (186K) | Supplementary information
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Articles
Weak pairwise correlations imply strongly correlated network states in a neural population p1007
Elad Schneidman, Michael J. Berry, II, Ronen Segev and William Bialek
doi:10.1038/nature04701
Abstract | Full Text | PDF (593K) | Supplementary information
Crystal structure of an Hsp90–nucleotide–p23/Sba1 closed chaperone complex p1013
Maruf M. U. Ali, S. Mark Roe, Cara K. Vaughan, Phillipe Meyer, Barry Panaretou, Peter W. Piper, Chrisostomos Prodromou and Laurence H. Pearl
doi:10.1038/nature04716
Abstract | Full Text | PDF (620K) | Supplementary information
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Letters
A low level of extragalactic background light as revealed by bold gamma-rays from blazars p1018
F. Aharonian, A. G. Akhperjanian, A. R. Bazer-Bachi, M. Beilicke, W. Benbow, D. Berge, K. Bernlöhr, C. Boisson, O. Bolz, V. Borrel, I. Braun, F. Breitling, A. M. Brown, P. M. Chadwick, L.-M. Chounet, R. Cornils, L. Costamante, B. Degrange, H. J. Dickinson, A. Djannati-Ataï, L. O'C. Drury, G. Dubus, D. Emmanoulopoulos, P. Espigat, F. Feinstein, G. Fontaine, Y. Fuchs, S. Funk, Y. A. Gallant, B. Giebels, S. Gillessen, J. F. Glicenstein, P. Goret, C. Hadjichristidis, D. Hauser, M. Hauser, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, W. Hofmann, M. Holleran, D. Horns, A. Jacholkowska, O. C. de Jager, B. Khélifi, S. Klages, Nu. Komin, A. Konopelko, I. J. Latham, R. Le Gallou, A. Lemière, M. Lemoine-Goumard, N. Leroy, T. Lohse, J. M. Martin, O. Martineau-Huynh, A. Marcowith, C. Masterson, T. J. L. McComb, M. de Naurois, S. J. Nolan, A. Noutsos, K. J. Orford, J. L. Osborne, M. Ouchrif, M. Panter, G. Pelletier, S. Pita, G. Pühlhofer, M. Punch, B. C. Raubenheimer, M. Raue, J. Raux, S. M. Rayner, A. Reimer, O. Reimer, J. Ripken, L. Rob, L. Rolland, G. Rowell, V. Sahakian, L. Saugé, S. Schlenker, R. Schlickeiser, C. Schuster, U. Schwanke, M. Siewert, H. Sol, D. Spangler, R. Steenkamp, C. Stegmann, J.-P. Tavernet, R. Terrier, C. G. Théoret, M. Tluczykont, C. van Eldik, G. Vasileiadis, C. Venter, P. Vincent, H. J. Völk and S. J. Wagner
doi:10.1038/nature04680
First paragraph | Full Text | PDF (218K) | Supplementary information
See also: Editor's summary | News and Views by Madau
Experimental determination of entanglement with a single measurement p1022
S. P. Walborn, P. H. Souto Ribeiro, L. Davidovich, F. Mintert and A. Buchleitner
doi:10.1038/nature04627
First paragraph | Full Text | PDF (232K)
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Polarons and confinement of electronic motion to two dimensions in a layered manganite p1025
H. M. Rønnow, Ch. Renner, G. Aeppli, T. Kimura and Y. Tokura
doi:10.1038/nature04650
First paragraph | Full Text | PDF (2,879K)
Climate sensitivity constrained by temperature reconstructions over the past seven centuries p1029
Gabriele C. Hegerl, Thomas J. Crowley, William T. Hyde and David J. Frame
doi:10.1038/nature04679
First paragraph | Full Text | PDF (533K) | Supplementary information
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Rapid discharge connects Antarctic subglacial lakes p1033
Duncan J. Wingham, Martin J. Siegert, Andrew Shepherd and Alan S. Muir
doi:10.1038/nature04660
First paragraph | Full Text | PDF (689K) | Supplementary information
See also: Editor's summary | News and Views by Clarke
A Cretaceous terrestrial snake with robust hindlimbs and a sacrum p1037
Sebastián Apesteguía and Hussam Zaher
doi:10.1038/nature04413
First paragraph | Full Text | PDF (428K) | Supplementary information
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Evolution of cooperative strategies from first principles p1041
Mikhail Burtsev and Peter Turchin
doi:10.1038/nature04470
First paragraph | Full Text | PDF (184K)
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DNA sequence of human chromosome 17 and analysis of rearrangement in the human lineage p1045
Michael C. Zody, Manuel Garber, David J. Adams, Ted Sharpe, Jennifer Harrow, James R. Lupski, Christine Nicholson, Steven M. Searle, Laurens Wilming, Sarah K. Young, Amr Abouelleil, Nicole R. Allen, Weimin Bi, Toby Bloom, Mark L. Borowsky, Boris E. Bugalter, Jonathan Butler, Jean L. Chang, Chao-Kung Chen, April Cook, Benjamin Corum, Christina A. Cuomo, Pieter J. de Jong, David DeCaprio, Ken Dewar, Michael FitzGerald, James Gilbert, Richard Gibson, Sante Gnerre, Steven Goldstein, Darren V. Grafham, Russell Grocock, Nabil Hafez, Daniel S. Hagopian, Elizabeth Hart, Catherine Hosage Norman, Sean Humphray, David B. Jaffe, Matt Jones, Michael Kamal, Varsha K. Khodiyar, Kurt LaButti, Gavin Laird, Jessica Lehoczky, Xiaohong Liu, Tashi Lokyitsang, Jane Loveland, Annie Lui, Pendexter Macdonald, John E. Major, Lucy Matthews, Evan Mauceli, Steven A. McCarroll, Atanas H. Mihalev, Jonathan Mudge, Cindy Nguyen, Robert Nicol, Sinéad B. O'Leary, Kazutoyo Osoegawa, David C. Schwartz, Charles Shaw-Smith, Pawel Stankiewicz, Charles Steward, David Swarbreck, Vijay Venkataraman, Charles A. Whittaker, Xiaoping Yang, Andrew R. Zimmer, Allan Bradley, Tim Hubbard, Bruce W. Birren, Jane Rogers, Eric S. Lander and Chad Nusbaum
doi:10.1038/nature04689
First paragraph | Full Text | PDF (325K) | Supplementary information
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Repeated morphological evolution through cis-regulatory changes in a pleiotropic gene p1050
Benjamin Prud'homme, Nicolas Gompel, Antonis Rokas, Victoria A. Kassner, Thomas M. Williams, Shu-Dan Yeh, John R. True and Sean B. Carroll
doi:10.1038/nature04597
First paragraph | Full Text | PDF (428K) | Supplementary information
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Synaptic scaling mediated by glial TNF-alpha p1054
David Stellwagen and Robert C. Malenka
doi:10.1038/nature04671
First paragraph | Full Text | PDF (3,061K) | Supplementary information
Unique features of action potential initiation in cortical neurons p1060
Björn Naundorf, Fred Wolf and Maxim Volgushev
doi:10.1038/nature04610
First paragraph | Full Text | PDF (519K) | Supplementary information
See also: Editor's summary | News and Views by Gutkin & Ermentrout
Enhanced bacterial clearance and sepsis resistance in caspase-12-deficient mice p1064
Maya Saleh, John C. Mathison, Melissa K. Wolinski, Steve J. Bensinger, Patrick Fitzgerald, Nathalie Droin, Richard J. Ulevitch, Douglas R. Green and Donald W. Nicholson
doi:10.1038/nature04656
First paragraph | Full Text | PDF (399K) | Supplementary information
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Spatiotemporal dynamics of RhoA activity in migrating cells p1069
Olivier Pertz, Louis Hodgson, Richard L. Klemke and Klaus M. Hahn
doi:10.1038/nature04665
First paragraph | Full Text | PDF (600K) | Supplementary information
Pharmaco-metabonomic phenotyping and personalized drug treatment p1073
T. Andrew Clayton, John C. Lindon, Olivier Cloarec, Henrik Antti, Claude Charuel, Gilles Hanton, Jean-Pierre Provost, Jean-Loïc Le Net, David Baker, Rosalind J. Walley, Jeremy R. Everett and Jeremy K. Nicholson
doi:10.1038/nature04648
First paragraph | Full Text | PDF (357K) | Supplementary information
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Designed divergent evolution of enzyme function p1078
Yasuo Yoshikuni, Thomas E. Ferrin and Jay D. Keasling
doi:10.1038/nature04607
First paragraph | Full Text | PDF (548K) | Supplementary information
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Naturejobs
Prospect
Physical exertion p1083
Enrolment in US graduate physics programmes shifts from foreign to domestic.
Paul Smaglik
doi:10.1038/nj7087-1083a
Full Text | PDF (149K)
Special Report
Seeing the big picture p1084
Creating a new drug is a long and painstaking process, involving the skills and talents of numerous types of scientist, says Hannah Hoag. Each is vital to different stages of producing a drug that's both safe and effective. Drug development draws on various kinds of scientist.
Hannah Hoag
doi:10.1038/nj7087-1084a
Full Text | PDF (570K)
Career Views
Thomas Baer, executive director, Stanford Photonics Research Center, California p1086
Industrial physicist returns to academic roots.
Virginia Gewin
doi:10.1038/nj7087-1086a
Full Text | PDF (129K)
Finding your north p1086
Website aims to help scientists locate true career calling.
Frederick Moore
doi:10.1038/nj7087-1086b
Full Text | PDF (129K)
The great Gatsby p1086
Graduate student learns from watching herself on TV.
Mhairi Dupré
doi:10.1038/nj7087-1086c
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Futures
The perfect lover p1088
In the heat of passion.
Paul Di Filippo
doi:10.1038/4401088a
Full Text | PDF (171K)
