| 2006年06月15日 Nature中英文摘要 | 点击： 作者： 来源： 时间： 2006-11-11 本站论坛
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Volume 441 Number 7095 pp785-906 15 June 2006
封面故事：飞机“凝结尾迹”对气候的影响
由高速飞行的飞机所产生的“凝结尾迹”（contrails）对地球的能量平衡有一个效应，这个效应与高空薄冰云对地球能量平衡所产生的效应相似。它们会将从地球及其大气层向外传播的长波辐射束缚住，并反射入射的太阳辐射。平均来说，长波效应占优势，净效应是气温变暖。该效应与由其他排放引起的效应相比是小的，但随着航空流量的增加，了解该现象也是很重要的。对英格兰东南上空所做的一项研究表明，该效应关键取决于“凝结尾迹”什么时候形成。夜间飞行占由“凝结尾迹”诱导产生的变暖的近80%，即便只有1/4的飞行发生在夜间。“凝结尾迹”的辐射性质和它们寿命很短的特点意味着，由航空运输的这个方面所造成的气候影响，有可能通过对航班时间重新进行精心编排减小到最低程度。
HIV-1表面上的蛋白刺
利用“冷电子显微镜断层扫描”方法所做的观测，以前所未有的详细程度显示了艾滋病病毒HIV-1表面上的蛋白刺。这些蛋白刺可让该病毒非常有效地与人体免疫细胞结合和融合。每个病毒体在每个粒子上平均有14个刺，其中的一些刺是聚集在一起的，这个特点与病毒组装、感染及中和机制都有关系。有一个出乎意料的发现：过去人们假设这种蛋白刺的柄由三个紧紧束缚在一起的杆组成，刺的头在最上边。而事实上它的柄是分成三条腿的，其形状就像一个三角架，这样可以使其与病毒膜的接触达到最大。
地球形成之初的谜团
对新形成的恒星所做的观测表明，太阳的行星体系是从一个平坦的气体和尘埃盘开始形成的，这个气体和尘埃盘快速（在大约10万年内）累积形成直径约10公里的小型行星。然后，在一个持续时间大约为3000万至4000万年的过程中，由这些小型行星累积形成了地球。Wood等人在本期Nature上发表了一篇综述文章，其内容是关于以下两个问题的最近的一些研究工作的：一是上面所说的累积增长过程的性质是什么，二是地球何以形成了一个富含铁的熔融核、而其中的低原子数元素含量高于形成地球的小型行星构造单元。
木星大小的行星周围只可能形成火星或月球大小的卫星
太阳系中位置靠外的巨型行星每个都有多个卫星，每个巨型行星的卫星体系的质量总和与该行星的质量之比都差不多——这些巨型行星的质量是它们全部卫星质量总和的10万倍。现在，已经找到了对这种一致性的一个可能的解释。在对一个通过积累氢气和石-冰固体而正在生长的巨型行星所做的数值模拟中，该行星的卫星体系的质量所占比例通过两个过程之间的一个平衡被调控为1：10万，这两个过程分别是：新物质向这些卫星的流入和由气体诱导的轨道衰减造成的物质损失。这个结果对于研究太阳系外的行星是有意义的：科学家曾认为，木星大小的行星周围的地球大小的卫星也许适合人类生存，但新的发现是，那种地方只可能形成火星或月球大小的卫星，所以该观点需要修正。
单细胞层次上的蛋白组学研究
一个活细胞产生数以千计的不同蛋白，调控这些蛋白的含量是细胞生物功能的关键。每种蛋白都只能以很少的数量产生，所以要对它们分别进行测定在技术上是困难的。但研究人员采用了一种新的策略，他们利用高通过量的流式细胞计量方法和荧光标记方法，来以单细胞分辨率对酵母中25000种以上的蛋白的含量进行监测。利用DNA微阵列方法也可以观察一个细胞对环境变化的反应，而该方法是从另一个角度来研究同一个问题。分析结果表明，不同蛋白的“噪音”水平部分取决于它们的功能。从事至关重要的“家务工作”的蛋白在不同细胞之间往往是统一的，但参与环境响应的蛋白则在不同细胞之间是不同的。影响噪音水平的其他因素包括一个蛋白在细胞内的位置及控制其产生的机制。
稳定的超冷原子对
在物理学中，物体之间彼此吸引、通过降低它们的能量而形成稳定的结合态是常见现象。但稳定的复合物即便有排斥性相互作用也能存在是有条件的。本期Nature报告了这样一个奇特的结合态的生成。它由一个光晶格中的一对超冷铷原子组成。这对铷原子之所以是稳定的，是因为处在一个有强排斥相互作用的光晶格的一个给定点上的两个铷原子无法衰变，因为它们无法将其势能转变成动能，这个现象可由关于超冷量子气体结构的Bose–Hubbard模型的约束条件来解释。
杂交在物种形成中所起的重要作用
物种形成一般被认为是由于一个品系分裂成了两个，但最近的研究表明，杂交（两个祖先种类通过杂交而不发生染色体数量变化形成第三个物种的现象）对于推动物种起源的作用比我们过去所意识到的要重要的多。该现象仍然被认为是少见的，但新的事例正在出现。最新的一例是热带蝴蝶Heliconius heurippa，科学家知道它有一个杂合的基因组，看起来像是另外两个物种（H. cydno 和 H. melpomene）之间的一种杂交。而且，实验表明，一个杂合的特征直接造成生殖隔离。过去，育种实验曾被用来重新生成H. heurippa的中间翅膀颜色， 并用来证明该物种鲜明的图案在生殖上将其与父辈物种隔离开来。
一种新形态的二氧化碳
高压改变凝聚态物质中原子间和分子间的相互作用，可深层次改变材料的物理和化学性质。这一现象在被称为“a-carbonia”的一种新发现的二氧化碳形态中得到了戏剧般地演示。这种非分子无定形二氧化碳是固体形态的分子二氧化碳的一种高压改变形态。它是一种玻璃质材料，与无定形硅石(SiO2)和锗石（GeO2）相似。该发现有可能在轻元素固体化学中开辟新的研究领域。
从神经生物学角度来研究好奇心
人类是非常好奇的，这种好奇心可帮助我们了解新环境和新的可能性。但常言说，好奇心，惹祸根。好奇心是有风险的，是有可能让我们付出代价的。统计学家、工程师和经济学家早就考虑到了如何平衡探索的成本与利益的问题。现在，涉及一项博弈任务和一次fMRI脑扫描的测试表明，人类在考虑自己的意见时似乎遵从类似的原理。参试者必须在两种欲望之间达成平衡：一种是根据积累的经验选择可能性最大的选项；另一种是选择一个不太熟悉、但有可能有更大回报的选项。大脑中有一个参与认知控制的区域，被称为frontopolar cortex。该区域在探索性决定过程中尤为活跃。这项研究的结果从神经生物学角度对人类的探索行为做了解释，并且指出了行为和神经研究的一个新领域。
细胞成分不断清除对于维持神经健康的重要性
本期Nature上两篇论文表明，蛋白降解和细胞成分清除的过程在维持神经系统健康中所起的作用可能比我们以前所想的更为重要。两个小组所做的研究都表明，抑制小鼠细胞的自吞作用，导致神经退化和过早死亡。自吞作用（细胞成分的蛋白降解和循环）对于一个细胞的正常生长和发育是很重要的。关于细胞成分不断清除对于维持神经健康来说非常重要的发现，将为关于神经退化疾病的研究工作开辟新的途径。
Contents
Editorials
Reaching a tipping point p785
A popular new paradigm for the nature of change pertains more to the social and political worlds than it does to the physical one.
doi:10.1038/441785a
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A fresh start p785
Will a change of management at Los Alamos put basic research under pressure?
doi:10.1038/441785b
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Cash-per-publication... p785
.....is an idea best avoided.
doi:10.1038/441786a
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Research Highlights
Research highlights p788
doi:10.1038/441788a
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News
Science academies target G8 agenda p790
National institutions coordinate efforts on global politics.
Declan Butler
doi:10.1038/441790a
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Koreans admit disguising stem-cell lines p790
Police investigation uncovers hospital's subterfuge.
David Cyranoski and Erika Check
doi:10.1038/441790b
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Sidelines p792
doi:10.1038/441792a
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Cash for papers: putting a premium on publication p792
Trend for financial incentives spreads in Asia.
Ichiko Fuyuno and David Cyranoski
doi:10.1038/441792b
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Goal fever at the World Cup p793
Why the first strike counts.
Michael Hopkin
doi:10.1038/441793a
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Born or made? Debate on mouse eggs reignites p795
Doubts deepen over whether mammals can make new eggs
Kendall Powell
doi:10.1038/441795a
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Nuclear reincarnation p796
Using nuclear power on a grand scale requires that spent nuclear fuel be reused. Emma Marris finds out which of the world's nations could jump on a reprocessing bandwagon.
doi:10.1038/441796a
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Snapshot: Atlantic in bloom p798
Plankton death throes off the Emerald Isle.
Jim Giles
doi:10.1038/441798a
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US satellite system loses climate sensors p798
Joint civilian-military programme culls weather instruments.
Jacqueline Ruttimann
doi:10.1038/441798b
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News in brief p800
doi:10.1038/441800a
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Correction p801
doi:10.1038/441801a
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News Features
Climate change: The tipping point of the iceberg p802
Could climate change run away with itself? Gabrielle Walker looks at the balance of evidence.
doi:10.1038/441802a
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Gerontology: Eat your cake and have it p807
Reducing your calorie intake makes you live longer — if you're a rat or a worm. Laura Spinney asks whether the same holds for humans — and if it does, whether the benefits could be put in a pill.
doi:10.1038/441807a
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Business
Burst of energy p810
More and more venture capitalists are backing clean technology in the United States, but will it take off? Virginia Gewin reports.
doi:10.1038/441810a
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In brief p811
doi:10.1038/441811a
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Market watch p811
Colin Macilwain
doi:10.1038/441811b
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Correspondence
Women editors: change comes from focused action p812
Linda G. Baum
doi:10.1038/441812a
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Women editors: we need more female scientists p812
Sarah P. Otto
doi:10.1038/441812b
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Women editors: nominees turned down Evolution job p812
Don Waller
doi:10.1038/441812c
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'Referee factor' would reward a vital contribution p812
Rory Wilson
doi:10.1038/441812d
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Still light-years away from articulating the infinite p812
Ian Stewart
doi:10.1038/441812e
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Books and Arts
In your own image p813
Care must be taken when looking for natural selection to explain the evolution of human behaviour.
Kenneth M. Weiss and Anne V. Buchanan review Before the Dawn: Recovering the Lost History of Our Ancestors by Nicholas Wade
doi:10.1038/441813a
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Reaching for the stars p814
Giovanni Bignami reviews Europe's Quest for the Universe by Lodewijk Woltjer
doi:10.1038/441814a
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A growing urban problem p815
Frank Schweitzer reviews Cities and Complexity: Understanding Cities with Cellular Automata, Agent-Based Models, and Fractals by Michael Batty
doi:10.1038/441815a
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A healthy interest p815
W. F. Bynum reviews Doctor Franklin's Medicine by Stanley Finger
doi:10.1038/441815b
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Science in culture: Home from home p816
History is brought to life at Benjamin Franklin's house in London.
Colin Martin
doi:10.1038/441816a
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News and Views
Structural biology: Images from the surface of HIV p817
Human and monkey immunodeficiency viruses are studded with 'spikes' that enable them to infect cells. Structural studies reveal that these spikes are tripod-like assemblies that cluster on the virus surface.
Dennis R. Burton
doi:10.1038/441817a
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Material science: Oxygen breaks into carbon world p818
When oxygen atoms bind to a graphite surface, they fall into line and make bridges across carbon atoms. This is the spearhead of a chemical attack in which the atomic arrangement of solid carbon is torn apart.
Pulickel M. Ajayan and Boris I. Yakobson
doi:10.1038/441818a
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Neurodegeneration: Good riddance to bad rubbish p819
Autophagy — cellular 'self-eating' — can be induced by stress, but it also acts continuously in a housekeeping role, disposing of unwanted proteins. Can it protect against neurodegenerative diseases?
Daniel J. Klionsky
doi:10.1038/441819a
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Quantum physics: United through repulsion p820
Mutually repulsive atoms placed at periodic intervals in a 'crystal of light' can, counterintuitively, be forced into stable couplings. That theoretical prediction has just seen experimental confirmation.
Leonardo Fallani and Massimo Inguscio
doi:10.1038/441820a
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Biomaterials: Silk spin-off p821
Helen Dell
doi:10.1038/441821a
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Neuroeconomics: Best to go with what you know? p822
In a changing world, how do we decide our best option? How do we settle between picking something familiar or trying out a new, possibly more rewarding, choice?
Daeyeol Lee
doi:10.1038/441822a
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Solid-state chemistry: A glass of carbon dioxide p823
Carbon is unusual in its family of elements because it has gaseous oxides. But under high pressure, carbon dioxide forms crystalline solids and can become a glass — so revealing the chemical family resemblance.
Paul F. McMillan
doi:10.1038/441823a
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Obituary: Bruce Merrifield (1921–2006) p824
Inventor of solid-phase peptide synthesis.
Stephen Kent
doi:10.1038/441824a
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Review
Accretion of the Earth and segregation of its core p825
Bernard J. Wood, Michael J. Walter and Jonathan Wade
doi:10.1038/nature04763
Abstract | Full Text | PDF (766K)
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Articles
A common mass scaling for satellite systems of gaseous planets p834
Robin M. Canup and William R. Ward
doi:10.1038/nature04860
Abstract | Full Text | PDF (305K) | Supplementary information
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Single-cell proteomic analysis of S. cerevisiae reveals the architecture of biological noise p840
John R. S. Newman, Sina Ghaemmaghami, Jan Ihmels, David K. Breslow, Matthew Noble, Joseph L. DeRisi and Jonathan S. Weissman
doi:10.1038/nature04785
Abstract | Full Text | PDF (1,099K) | Supplementary information
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Distribution and three-dimensional structure of AIDS virus envelope spikes p847
Ping Zhu, Jun Liu, Julian Bess, Jr, Elena Chertova, Jeffrey D. Lifson, Henry Grisé, Gilad A. Ofek, Kenneth A. Taylor and Kenneth H. Roux
doi:10.1038/nature04817
Abstract | Full Text | PDF (491K) | Supplementary information
See also: Editor's summary | News and Views by Burton
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Letters
Repulsively bound atom pairs in an optical lattice p853
K. Winkler, G. Thalhammer, F. Lang, R. Grimm, J. Hecker Denschlag, A. J. Daley, A. Kantian, H. P. Büchler and P. Zoller
doi:10.1038/nature04918
First paragraph | Full Text | PDF (291K)
See also: Editor's summary | News and Views by Fallani & Inguscio
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Amorphous silica-like carbon dioxide p857
Mario Santoro, Federico A. Gorelli, Roberto Bini, Giancarlo Ruocco, Sandro Scandolo and Wilson A. Crichton
doi:10.1038/nature04879
First paragraph | Full Text | PDF (433K) | Supplementary information
See also: Editor's summary | News and Views by McMillan
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Control of four stereocentres in a triple cascade organocatalytic reaction p861
Dieter Enders, Matthias R. M. Hüttl, Christoph Grondal and Gerhard Raabe
doi:10.1038/nature04820
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The importance of the diurnal and annual cycle of air traffic for contrail radiative forcing p864
Nicola Stuber, Piers Forster, Gaby Rädel and Keith Shine
doi:10.1038/nature04877
First paragraph | Full Text | PDF (214K)
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Speciation by hybridization in Heliconius butterflies p868
Jesús Mavárez, Camilo A. Salazar, Eldredge Bermingham, Christian Salcedo, Chris D. Jiggins and Mauricio Linares
doi:10.1038/nature04738
First paragraph | Full Text | PDF (360K) | Supplementary information
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Sperm storage induces an immunity cost in ants p872
Boris Baer, Sophie A. O. Armitage and Jacobus J. Boomsma
doi:10.1038/nature04698
First paragraph | Full Text | PDF (222K) | Supplementary information
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Cortical substrates for exploratory decisions in humans p876
Nathaniel D. Daw, John P. O'Doherty, Peter Dayan, Ben Seymour and Raymond J. Dolan
doi:10.1038/nature04766
First paragraph | Full Text | PDF (292K) | Supplementary information
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Loss of autophagy in the central nervous system causes neurodegeneration in mice p880
Masaaki Komatsu, Satoshi Waguri, Tomoki Chiba, Shigeo Murata, Jun-ichi Iwata, Isei Tanida, Takashi Ueno, Masato Koike, Yasuo Uchiyama, Eiki Kominami and Keiji Tanaka
doi:10.1038/nature04723
First paragraph | Full Text | PDF (521K) | Supplementary information
See also: Editor's summary | News and Views by Klionsky
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Suppression of basal autophagy in neural cells causes neurodegenerative disease in mice p885
Taichi Hara, Kenji Nakamura, Makoto Matsui, Akitsugu Yamamoto, Yohko Nakahara, Rika Suzuki-Migishima, Minesuke Yokoyama, Kenji Mishima, Ichiro Saito, Hideyuki Okano and Noboru Mizushima
doi:10.1038/nature04724
First paragraph | Full Text | PDF (514K) | Supplementary information
See also: Editor's summary | News and Views by Klionsky
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Interleukin-2 signals during priming are required for secondary expansion of CD8+ memory T cells p890
Matthew A. Williams, Aaron J. Tyznik and Michael J. Bevan
doi:10.1038/nature04790
First paragraph | Full Text | PDF (536K) | Supplementary information
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Signal peptide peptidase is required for dislocation from the endoplasmic reticulum p894
Joana Loureiro, Brendan N. Lilley, Eric Spooner, Vanessa Noriega, Domenico Tortorella and Hidde L. Ploegh
doi:10.1038/nature04830
First paragraph | Full Text | PDF (451K) | Supplementary information
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CRD-BP mediates stabilization of TrCP1 and c-myc mRNA in response to -catenin signalling p898
Felicite K. Noubissi, Irina Elcheva, Neehar Bhatia, Abbas Shakoori, Andrei Ougolkov, Jianghuai Liu, Toshinari Minamoto, Jeff Ross, Serge Y. Fuchs and Vladimir S. Spiegelman
doi:10.1038/nature04839
First paragraph | Full Text | PDF (462K) | Supplementary information
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Corrigendum: A brain-specific microRNA regulates dendritic spine development p902
Gerhard M. Schratt, Fabian Tuebing, Elizabeth A. Nigh, Christina G. Kane, Mary E. Sabatini, Michael Kiebler and Michael E. Greenberg
doi:10.1038/nature04909
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Corrigendum: Brain-state- and cell-type-specific firing of hippocampal interneurons in vivo p902
Thomas Klausberger, Peter J. Magill, László F. Márton, J. David B. Roberts, Philip M. Cobden, György Buzsáki and Peter Somogyi
doi:10.1038/nature04910
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Corrigendum: Universal scaling of respiratory metabolism, size and nitrogen in plants p902
Peter B. Reich, Mark G. Tjoelker, Jose-Luis Machado and Jacek Oleksyn
doi:10.1038/nature04911
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Naturejobs
Prospect
Prospect p903
Taking a break can lend focus.
Paul Smaglik
doi:10.1038/nj7095-903a
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Careers and Recruitment
Nicholas Schork, director, Center for Biomedical Informatics; co-director, Cancer Genetics Program, University of California, San Diego p904
Nicholas Schork moves on to biomedical informatics.
Virginia Gewin
doi:10.1038/nj7095-904a
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A physics walkabout p904
NSF postdoc does physics down under.
Charles Tahan
doi:10.1038/nj7095-904b
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Graduation joy p904
The joy and trepidation of graduation.
Andreas Andersson
doi:10.1038/nj7095-904c
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Futures
Great unreported discoveries no. 163 p906
It's good to talk...
Mike Resnick
doi:10.1038/441906a
Full Text | PDF (154K)
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