| 2005年01月27日 Nature中文摘要 | 点击： 作者： 来源： 时间： 2006-11-11 本站论坛
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|  | Volume 433 Number 7024 pp339-442
封面故事：梅毒流行的周期性
过去50年里美国多次梅毒流行有一个大致为10年的周期，这种波动被认为是由于性行为的变化，但根据自1941年以来从68个城市收集的病例报告数据所做的一项新的分析表明，它们是发病率的自然波动，与寄主免疫能力有关。美国城市之间梅毒流行越来越同步，说明性行为网络的联系越来越紧密：目前同步的梅毒爆发可能是由于无免疫能力的个体的累积，而不是由于人们回归不安全的性行为。（Letters, p. 417; News and Views）封面图片：梅毒病原体Treponema pallidum的电子显微图（Alfred Pasieka/ Science Photo Library）
怎样利用电视传播科学知识
美国和欧洲近一办成年人从电视上获得科学知识，其中多数是从轻松的大众节目和地方新闻节目中获得的，而不是从公共广播频道的纵深记实节目中获得的。在本期Commentary文章中，Eliene Augenbraun认为，科学家和他们所在单位的新闻部门应更多关注能够接触到多数人的媒体，即商业电视。这意味着要使科学信息视觉化，使其与目标受众的日常生活有关。
关于宇宙中暗物质的新结果
在“大爆炸”后不久，宇宙几乎是完全平静的、均匀的，但在物质分布上也有隐藏的小波动，从“大爆炸”之后2000万年起，这些波动开始经历引力坍塌。对接下来要发生的事情来说的一个关键是构成宇宙大部分结构的神秘暗物质的性质。有一种假想的粒子名为“中性伴随子”（Neutralino），科学家假设，该粒子是暗物质的主要成分。根据这一假设所做的新的超级计算机计算结果表明，宇宙中形成的最早的结构是与木星质量相同的暗物质晕轮，大小相当于太阳系。这些新的计算结果说明，我们的银河系中有足够多的这些物质，可供太阳系每1万年从暗物质云穿过一次。这些结果对于那些数量越来越多的正在进行当中或处在规划阶段的、以识别暗物质性质为目标的实验具有参考价值。
“无尺度”网络的共同特点
“无尺度”网络，如互联的网页、社会团体中的人、或细胞和蛋白相互作用网络，表现出不均匀的连接性分布，即每个节点没有典型数目的链节。这些网络中有很多还展现出“小世界”效应，在社会学上被称为“六种程度的分离”。对这种网络所做的一项新的分析（在此项分析中，节点被分隔进不同大小的盒子内）显示，它们有一个令人吃惊的共同特点，即自我相似性。换句话说，这些网络是按照不同长度尺度或“不同分离程度”由自重复模式构造成的，类似于几何学中的不规则结构。这一发现可帮助解释这种网络的无尺度性质是怎样出现的。
温室效应的量化模型研究
在“climateprediction.net"项目中，数以千计的人自愿贡献出他们PC上的剩余计算能力，来帮助对我们的气候响应温室气体浓度升高的方式中所存在的不确定性进行量化。通过将一个先进的气候模型运行数千次，有可能找出该模型是怎样对无法明确计算出的物理过程的近似值的微小变化做出反应的。现在，第一批结果已经被分析出来，在真实反映气候条件的模拟中，地表温度的变化范围从低于2摄氏度到高于11摄氏度。这些数值代表着可能的长期变化，是整个地球的平均值，是通过在模型中将大气中CO2浓度加倍获得的。复杂模型被发现有如此宽的响应范围这还是第一次。它们的存在可帮助量化与区域水平上的气候变化相关的风险。
地球陆地上“丢失的”硅找到了
硅是地球上第二种含量最多的元素，参与重要的陆地和海洋生物化学过程。然而，人们对其陆地循环没有很好定量，在硅同位素预算中有一个“丢失的”硅库。海洋和河流中的水与火成岩相比富含硅-30，说明有一个耗尽了硅-30的未知的大陆硅库。现在，在新一代质谱仪的帮助下，Basile-Doelsch等人获得了对来自法国南部沙岩的石英中硅同位素的实地测定数据。测定结果表明，样品中硅-30的消耗程度比以前报告的任何陆地样品中都大，这说明由石英在土壤和地下水中沉淀所形成的硅酸化岩石可解释所“丢失的”硅库。
埃特纳火山喷发的能量来源
埃特纳火山2000年的喷发之所以引人注目，是因为它有一组多达64个的周期性熔岩喷孔，将熔岩碎片喷到近900米的高空。科学家提出，此次火山喷发有两个能量来源：一个是岩浆本身在其迅速上升过程中所释放的气体；另一个是深层积累的气体所造成的压力的累积。确定二者中哪个是火山喷发的驱动力一直很困难。但埃特纳火山的一个喷孔为火山学家提供了利用遥感技术来确定气相的红外光谱的机会。火山学家通过这种方法测定出了作为这一喷孔动力来源的气体的化学组成，其结果与该气体来源于一个累积的气体层的假设是一致的。
不同物种为什么能共存
了解遗传多样性在自然界是怎样维持的是一个根本性的问题。现有理论所假设的种群动态过于简单，尽管这些动态很少得到证据支持。例如，在海洋浮游生物生态学的核心就有一个矛盾：这么多不同的物种是怎样靠基本上是相同的一个资源库共存的，而又没有一种或另一种物种居于支配地位？用水蚤及其藻类猎物所做的精巧的实验表明，答案在于竞争物种的生命阶段的时间选择上。每个物种都包括处于不同生命阶段的个体群，它们在一年不同时间有不同需求和不同丰度。由于丰度的高峰和低谷很少赶在同一时间，所以生态系统中有足够空间供所有物种共存
生态系统多样性与稳定性之间的关系
研究发现，较大的生物多样性能增强小片土地上的生态稳定性，这种效应持续的时间从几个星期到几十年不等。但要使多样性与稳定性之间的联系对生态学家来说达到有意义的程度，必须能够证明这种联系会在大范围内和长时间段上发生。对古珊瑚所做的一项新的研究表明，多样性与稳定性之间的关系在地质时间尺度上会留下痕迹，可按比例放大到数百万年的时间和全球的规模。化石记录中所保留下来的礁石生态系统中变化的分类多样性表明，在一个给定的1000万年的时间间隔内，礁石平均多样性越大，在下一个时间间隔内礁石生态的变化越小。礁石如果能产生数量更多的物种的话，它们发生变化的可能性会较小，但这也可能意味着，面对全球变化，今天多样化的礁石也许不能很快适应。
植物为什么也有敏捷的动作
捕蝇草只需100毫秒就能捕获其猎物，是植物界最快的动作之一。其触发毛对刺激的生化反应和一个动作势能通过叶子传播的方式都已经很清楚，不太清楚的是其捕蝇器的刺激后闭合机制。现在，研究人员利用高速摄像技术、显微技术和力测定技术，发现捕蝇草的快速闭合机制来自一种机械挫曲不稳定性。捕蝇草双曲叶的几何特征提供了一个机制，该机制可以先储存、然后释放弹性能量。了解植物的其他快速动作是否采用类似机制或是否形成了一系列不同机制将是很有趣的。
本期目录：
Editorials
Summers' winter of discontent p339
The president of Harvard has learnt a painful lesson in public communication. The media and Harvard academics may have over-reacted to his comments about women in science, but there is an opportunity to benefit from the affair.
doi: 10.1038/433339a
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Data sharing for disasters p339
Last month's tsunami and its aftermath have highlighted a need for more science — and more effective sharing of data.
doi: 10.1038/433339b
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Top of pageNews
Medicare compels heart patients to enlist in follow-up research p341
Pacemakers come with strings attached in United States.
Meredith Wadman
doi: 10.1038/433341a
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NASA urged to lay plans for mission to Europa p342
Scientists put Jupiter's moon in their sights.
Tony Reichhardt
doi: 10.1038/433342a
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Cash shortall threatens to rock US geophysics project p342
EarthScope researchers fight for cash to study the inner Earth.
Rex Dalton
doi: 10.1038/433342b
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Solo efforts hamper tsunami warning system p343
Lack of coordination and data sharing causes global confusion.
David Cyranoski
doi: 10.1038/433343a
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A system that works ... if people listen p343
David Cyranoski
doi: 10.1038/433343b
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Europe pares down double patents on breast-cancer gene p344
Decision to restrict patents poses ethnic ethical conundrum.
Alison Abbott
doi: 10.1038/433344a
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Infection scare inflames fight against biodefence network p344
Accidental cases of tularaemia reduce faith in biocontainment labs.
Rex Dalton
doi: 10.1038/433344b
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Global vaccine project gets a shot in the arm p345
Gates foundation and Norwegian government give total of US$1 billion.
Erika Check
doi: 10.1038/433345a
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MIT wraps up Dublin lab following funding failure p345
Ireland's Media Lab closes after less than five years of operation.
Roxanne Khamsi
doi: 10.1038/433345b
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news in brief p346
doi: 10.1038/433346a
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Top of pageNews Features
On the trail of destruction p350
Quirin Schiermeier travels to Sri Lanka with a team of scientists in the wake of last month's tsunami. Together with locals they search through the damage for clues of where the wave hit hardest.
doi: 10.1038/433350a
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Get off the beach — now! p354
doi: 10.1038/433354a
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Top of pageCorrespondence
A right to voice dissent against the establishment p355
Is science the new dogma? Can religion coexist with progress? You debate the issues.
Ben MacArthur
doi: 10.1038/433355a
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Science flourishes in a secular democracy p355
doi: 10.1038/433355b
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It's not just theologians who are morally troubled p355
Stephen J. McSorley
doi: 10.1038/433355c
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Eastern creeds are less dogmatic about scripture p355
Rahul Siddharthan
doi: 10.1038/433355d
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Top of pageCommentary
Weapon of mass attraction p357
Scientists should embrace, not fear, television news.
Eliene Augenbraun
doi: 10.1038/433357a
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Top of pageBooks and Arts
Armed only with knowledge p359
Physicist Patrick Blackett made a stand against atomic weapons.
doi: 10.1038/433359a
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Living with viruses p360
doi: 10.1038/433360a
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Peering out of the box p361
doi: 10.1038/433361a
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Video installation: Twin peaks p361
doi: 10.1038/433361b
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Top of pagePhysics detective
Schr?dinger's mousetrap p363
Part 2: Enter the detective.
Neil Mathur
doi: 10.1038/433363a
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Top of pageNews and Views
Complex systems: Romanesque networks p365
Newly won evidence shows that many real-world network systems obey a power-law scaling, just as if they were fractal shapes. Could this be the harbinger of a new architectural law for complex systems?
Steven H. Strogatz
doi: 10.1038/433365a
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Sexually transmitted diseases: Epidemic cycling and immunity p366
Are syphilis epidemics caused by external factors such as human sexual behaviour, or are factors intrinsic to the pathogen more important? Comparing the dynamics of syphilis and gonorrhoea provides some clues.
Bryan Grenfell and Ottar Bj?rnstad
doi: 10.1038/433366a
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Cell biology: Border crossing p367
The 'translocon' complex, which determines whether a protein segment will be inserted into or pushed through the cell membrane, seems to make the decision by performing a thermodynamic measurement.
James U. Bowie
doi: 10.1038/433367a
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Materials science: Build your own superlattice p369
Artificial materials made from oxide building blocks turn out to be excellent ferroelectrics. This shows that materials with specific properties can be designed by atomic-scale tailoring of their composition.
Guus Rijnders and Dave H. A. Blank
doi: 10.1038/433369a
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Ecology: Paradise sustained p370
Biodiversity stabilizes ecosystem functioning in small-scale, short-term experiments, but do such findings scale up to the larger world? A global study of fossil reefs from the past 500 million years suggests they do.
Shahid Naeem and Andrew C. Baker
doi: 10.1038/433370a
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100 and 50 years ago p371
doi: 10.1038/433371a
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Obituary: Maclyn McCarty (1911?2005) p372
Richard M. Krause
doi: 10.1038/433372a
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research highlights p373
doi: 10.1038/433373a
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Top of pageBrief Communications
Sexual behaviour: Rapid speciation in an arthropod p375
The likely force behind an explosion of new Hawaiian cricket species is revealed.
Tamra C. Mendelson and Kerry L. Shaw
doi: 10.1038/433375a
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Oscillatory motion: Quantum whistling in superfluid helium-4 p376
E. Hoskinson, R. E. Packard and Thomas M. Haard
doi: 10.1038/433376a
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Top of pageBrief Communications Arising
Marine ecology: Different measures of biodiversity pE9
John R. Dolan
doi: 10.1038/nature03320
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Marine ecology: Different measures of biodiversity (Reply) pE9
Xabier Irigoien, Jef Huisman and Roger P. Harris
doi: 10.1038/nature03321
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Top of pageArticles
Recognition of transmembrane helices by the endoplasmic reticulum translocon p377
Tara Hessa, Hyun Kim, Karl Bihlmaier, Carolina Lundin, Jorrit Boekel, Helena Andersson, IngMarie Nilsson, Stephen H. White and Gunnar von Heijne
doi: 10.1038/nature03216
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Drosophila Spire is an actin nucleation factor p382
Margot E. Quinlan, John E. Heuser, Eugen Kerkhoff and R. Dyche Mullins
doi: 10.1038/nature03241
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Top of pageLetters to Nature
Earth-mass dark-matter haloes as the first structures in the early Universe p389
J. Diemand, B. Moore and J. Stadel
doi: 10.1038/nature03270
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Self-similarity of complex networks p392
Chaoming Song, Shlomo Havlin and Hernán A. Makse
doi: 10.1038/nature03248
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Strong polarization enhancement in asymmetric three-component ferroelectric superlattices p395
Ho Nyung Lee, Hans M. Christen, Matthew F. Chisholm, Christopher M. Rouleau and Douglas H. Lowndes
doi: 10.1038/nature03261
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Another continental pool in the terrestrial silicon cycle p399
Isabelle Basile-Doelsch, Jean Dominique Meunier and Claude Parron
doi: 10.1038/nature03217
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Uncertainty in predictions of the climate response to rising levels of greenhouse gases p403
D. A. Stainforth, T. Aina, C. Christensen, M. Collins, N. Faull, D. J. Frame, J. A. Kettleborough, S. Knight, A. Martin, J. M. Murphy, C. Piani, D. Sexton, L. A. Smith, R. A. Spicer, A. J. Thorpe and M. R. Allen
doi: 10.1038/nature03301
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Spectroscopic evidence for a lava fountain driven by previously accumulated magmatic gas p407
Patrick Allard, Mike Burton and Filippo Muré
doi: 10.1038/nature03246
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Long-term relationships between ecological stability and biodiversity in Phanerozoic reefs p410
Wolfgang Kiessling
doi: 10.1038/nature03152
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Stage-structured cycles promote genetic diversity in a predator?prey system of Daphnia and algae p413
William A. Nelson, Edward McCauley and Frederick J. Wrona
doi: 10.1038/nature03212
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Host immunity and synchronized epidemics of syphilis across the United States p417
Nicholas C. Grassly, Christophe Fraser and Geoffrey P. Garnett
doi: 10.1038/nature03072
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How the Venus flytrap snaps p421
Yo?l Forterre, Jan M. Skotheim, Jacques Dumais and L. Mahadevan
doi: 10.1038/nature03185
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Simulation and validation of modelled sphingolipid metabolism in Saccharomyces cerevisiae p425
Fernando Alvarez-Vasquez, Kellie J. Sims, L. Ashley Cowart, Yasuo Okamoto, Eberhard O. Voit and Yusuf A. Hannun
doi: 10.1038/nature03232
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APOBEC3G cytidine deaminase inhibits retrotransposition of endogenous retroviruses p430
Cécile Esnault, Odile Heidmann, Frédéric Delebecque, Marie Dewannieux, David Ribet, Allan J. Hance, Thierry Heidmann and Olivier Schwartz
doi: 10.1038/nature03238
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Chd1 chromodomain links histone H3 methylation with SAGA- and SLIK-dependent acetylation p434
Marilyn G. Pray-Grant, Jeremy A. Daniel, David Schieltz, John R. Yates, III and Patrick A. Grant
doi: 10.1038/nature03242
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Top of pageNaturejobs
Central stations p439
Paul Smaglik
doi: 10.1038/nj7024-439a
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Homeward bound European Union p440
Quirin Schiermeier and Paul Smaglik
doi: 10.1038/nj7024-440a
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Graduate Journal: Seeking sources of information p442
Karolina Tkaczuk
doi: 10.1038/nj7024-442a
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Recruiters & Academia p442
Primal de Lanerolle
doi: 10.1038/nj7024-442b
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Movers p442
doi: 10.1038/nj7024-442c
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