14 July 2006 Vol 313, Issue 5784, Pages 144-239
霸王龙的生命史
霸王龙也许有与长寿的鸟类和哺乳类类似的生命史：它们很可能活过了未成熟期，大多数是在中年和晚年死亡的。人们对恐龙的生命史知之甚少，所以Gregory M. Erickson 和同事描绘的霸王龙的生命史也许能为了解恐龙行为提供线索，而且也许能解释为什么博物馆中几乎没有未成年恐龙的样品。研究人员分析了加拿大阿尔伯达省附近丰富的霸王龙化石沉积，这些化石代表了短时间段内死亡的一个种群，他们提出霸王龙的身体超过一定大小后活过未成熟期的可能性增加。中年阶段交配和掠食的压力增加了该阶段霸王龙死亡的可能性，而且最年长的化石表明，与不如类动物以及其它长寿物种类似，恐龙也受到衰老所带来的衰弱的影响。
报告：Tyrannosaur Life Tables: An Example of Nonavian Dinosaur Population Biology, Gregory M. Erickson, Philip J. Currie, Brian D. Inouye, and Alice A. Winn
大猫鼬教小猫鼬捕猎
有关野生猫鼬的新证据提出，人类也许不是主动教育下一代的唯一物种。动物世界中几乎看不到教育行为：一个个体传递给另一个个体技能的指导机制。Alex Thornton和Katherine McAuliffe现在显示，年长的猫鼬教幼小猫鼬如何抓取食物，老猫鼬用把美味推到里小猫鼬更近的地方、甚至把蝎子的螫针先摘掉再让小猫鼬试着抓等来增加猫鼬崽触摸活的被捕食动物的机会。随着猫鼬崽的长大和变得更熟练，老猫鼬也随着时间改变它们的行为。研究人员发现，教育对年长猫鼬来说是一种代价，因为它们从中得不到直接的好处，而且它们在这个过程中花不少的时间和力量。
报告：Teaching in Wild Meerkats, Alex Thornton and Katherine McAuliffe
找金矿的细菌
澳大利亚的金沙为细菌能对天然金块的形成有直接贡献提供了迄今为止最有力的证据。Frank Reith和同事显示，在两个金矿中，细菌生物膜与土壤中发现的几乎所有的金沙有关联，但与土壤本身没有关联。DNA测试表明这种探矿微生物大概是一种名为Ralstonia metallidurans的细菌。这种细菌也许通过沉降金作为一种给它们的环境解毒的方法，从而使金在细胞内积累，或者在某些情况下使细胞膜外镀一层金。
报告：Biomineralization of Gold: Biofilms on Bacterioform Gold, Frank Reith, Stephen L. Rogers, D. C. McPhail, and Daryl Webb
云、气溶胶、和气候
新的测量结果也许能帮助研究人员更好地了解气候变化中最大不确定因素之一：污染和烟雾气溶胶如何影响云覆盖？云覆盖的变化对降雨、海洋温度、以及其他气候变量能有很大的影响。Yoram Kaufman和Ilan Koren用一个叫AERONET的全球气溶胶遥感仪器网显示，云覆盖在有来自污染的烟雾的气溶胶浓度较高的地方增加。但是，增加的云覆盖意味着被气溶胶吸收的日光的减少。研究人员发现，气溶胶的类型以及它们的地理位置不影响这些关系。
科学特快报告：Smoke and Pollution Aerosol Effect on Cloud Cover, Yoram J. Kaufman and Ilan Koren
在纳米尺度控制摩擦力
本期有两项研究提出了在纳米尺度设备降低摩擦的不同方法。摩擦是机械设备中最古老的问题，在纳米尺度这个问题变得更为突出，在这个尺度的材料大多部分都受到表面磨损，而且在小关闭空间中润滑剂会变得稠和黏。现在，Anisoara Socoliuc和同事显示，通过垂直于界面的一个摩擦力显微镜的硅探针滑过氯化钠晶体时产生的小振动力，如何能在这样的系统中降低摩擦。在一个类似的系统中，Jeong Young Park和同事通过用施加给参杂的硅表面不同的电荷量来控制摩擦。这两种技术降低了在原子尺度表面间相互作用中常见的粘住-滑动运动。在一篇相关的研究评述中，Robert Carpick讨论了为什么在纳米和微米尺度设备中必须克服摩擦才能使这些设备在商业意义。
报告：Atomic-Scale Control of Friction by Actuation of Nanometer-Sized Contacts, Anisoara Socoliuc, et al.
简报：Electronic Control of Friction in Silicon pn Junctions, Jeong Young Park, D. F. Ogletree, P. A. Thiel, and M. Salmeron
研究评述：Controlling Friction, Robert W. Carpick
将隧道结研究提到新水平
隧道结由两个金属电极和一个将其隔开的绝缘材料组成，电子能从一个电极穿越过障碍到另一个电极，本期一篇研究评述说，绝缘材料的性质是新型隧道结的关键。Evgeny Tsymbal 和Hermann Kohlstedt讨论了新隧道结的一种：铁电隧道结，这种隧道结用铁电材料作为绝缘层。该材料中的电子极化能通过一个外加电场来控制，这个隧道结增加了一个新的性质，而且可能带来全新的电子部件。如果将这种隧道结中的普通金属电极改为铁磁金属，则能产生更多的可能性，使这些隧道结同时具有铁磁和铁电的性质。
研究评述：Tunneling Across a Ferroelectric, Evgeny Y. Tsymbal and Hermann Kohlstedt
Contents
This Week in Science
Editor summaries of this week's papers.
Science 14 July 2006: 144.
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Editorial:
German Science Policy 2006
Angela Merkel
Science 14 July 2006: 147.
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Editors' Choice
Highlights of the recent literature.
Science 14 July 2006: 148.
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NetWatch
Best of the Web in science.
Science 14 July 2006: 151.
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Quarterly Author Index
Science 14 July 2006: 239.
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NEW PRODUCTS
Science 14 July 2006: 239.
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News of the Week
CANCER RESEARCH: Fake Data, but Could the Idea Still Be Right?
Jennifer Couzin
Science 14 July 2006: 154.
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STEM CELLS: Team Claims Success With Cow-Mouse Nuclear Transfer
Gretchen Vogel
Science 14 July 2006: 155-156.
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STEM CELLS: Ethical Oocytes: Available for a Price
Gretchen Vogel
Science 14 July 2006: 155.
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EVOLUTION: Competition Drives Big Beaks Out of Business
Elizabeth Pennisi
Science 14 July 2006: 156.
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PLANETARY SCIENCE: Long-Term Mars Exploration Under Threat, Panel Warns
Andrew Lawler
Science 14 July 2006: 157.
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PALEONTOLOGY: Vigorous Youth for Tyrannosaurs
Erik Stokstad
Science 14 July 2006: 158.
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PLANETARY SCIENCE: Peeling Back One More Layer of Asteroid Mystery
Richard A. Kerr
Science 14 July 2006: 158-159.
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MICROBIOLOGY: Bacteria Help Grow Gold Nuggets From Dirt
Richard A. Kerr
Science 14 July 2006: 159.
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ScienceScope
Science 14 July 2006: 157.
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Random Samples
Science 14 July 2006: 153.
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Newsmakers
Science 14 July 2006: 167.
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News Focus
BIOMEDICINE: Selling the Stem Cell Dream
Martin Enserink
Science 14 July 2006: 160-163.
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NANOTECHNOLOGY: Pretty as You Please, Curling Films Turn Themselves Into Nanodevices
Adrian Cho
Science 14 July 2006: 164-165.
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SCIENCE EDUCATION: A Strategy That Works: Hook 'Em While They're Young
Jerry Guo
Science 14 July 2006: 166.
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Letters
This Week's Letters
Science 14 July 2006: 169.
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Difficulties for Foreign Scientists in Coming to the United States
Christopher F. D'Elia, Gaylen Bradley, and Roland Schmitt
Science 14 July 2006: 169.
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Bridging the Divide or Deepening It?
Edgar Pick
Science 14 July 2006: 169-170.
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Scientific Activity Should Have No Borders
Francisco Leon
Science 14 July 2006: 170.
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Reexamining Fusion Power
Chauncey Starr, Robert L. Hirsch, Herman Dieckamp, Leonard J. Koch;, Robert Bourque;, Niek Lopes Cardozo, Alex Bradshaw, and Paul Vandenplas
Science 14 July 2006: 170-171.
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Auxin Signaling in Plant Defense
Roseline Remans, Stijn Spaepen, and Jos Vanderleyden
Science 14 July 2006: 171.
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Women Science Faculty at MIT
Robert J. Silbey
Science 14 July 2006: 171.
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Clarifying Cancer Mortality Rates
Carolyn D. Runowicz
Science 14 July 2006: 171-172.
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Books et al.
ANTHROPOLOGY: From Foraging to Planting
Deborah M. Pearsall
Science 14 July 2006: 173-174.
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HUMAN EVOLUTION: Silverbacks and Their Satellites
Rebecca L. Cann
Science 14 July 2006: 174.
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Books Received
Science 14 July 2006: 174.
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Policy Forum
PUBLIC HEALTH: Diabetes and Disease Surveillance
Amy L. Fairchild
Science 14 July 2006: 175-176.
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Perspectives
BIOCHEMISTRY: Viral Glycoproteins and an Evolutionary Conundrum
Alasdair C. Steven and Patricia G. Spear
Science 14 July 2006: 177-178.
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ASTRONOMY: The Supernova Origin of Interstellar Dust
Eli Dwek
Science 14 July 2006: 178-180.
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CELL BIOLOGY: Actin Discrimination
J. Chloë Bulinski
Science 14 July 2006: 180-181.
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APPLIED PHYSICS: Tunneling Across a Ferroelectric
Evgeny Y. Tsymbal and Hermann Kohlstedt
Science 14 July 2006: 181-183.
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SIGNAL TRANSDUCTION: Calcium Entry Signals--Trickles and Torrents
Donald L. Gill, Maria A. Spassova, and Jonathan Soboloff
Science 14 July 2006: 183-184.
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PHYSICS: Controlling Friction
Robert W. Carpick
Science 14 July 2006: 184-185.
Summary »| Full Text »| PDF »|
Brevia
Electronic Control of Friction in Silicon pn Junctions
Jeong Young Park, D. F. Ogletree, P. A. Thiel, and M. Salmeron
Science 14 July 2006: 186.
Depletion or accumulation of charge unexpectedly modifies the friction between a silicon surface and the metal-coated tip of an atomic-force microscope.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Research Articles
Crystal Structure of the Low-pH Form of the Vesicular Stomatitis Virus Glycoprotein G
Stéphane Roche, Stéphane Bressanelli, Félix A. Rey, and Yves Gaudin
Science 14 July 2006: 187-191.
Glycoprotein G from an RNA virus shows a reversible conformational change upon fusion with the host cell and is homologous to glycoprotein gB from herpesvirus.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Arginylation of ß-Actin Regulates Actin Cytoskeleton and Cell Motility
Marina Karakozova, Marina Kozak, Catherine C. L. Wong, Aaron O. Bailey, John R. Yates, III, Alexander Mogilner, Henry Zebroski, and Anna Kashina
Science 14 July 2006: 192-196.
Published online 22 June 2006 [DOI: 10.1126/science.1129344] (in Science Express Research Articles)
Addition of an amino acid to actin modulates its properties, affecting (for example) its localization and the formation of lamellae in motile cells.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Massive-Star Supernovae as Major Dust Factories
Ben E. K. Sugerman, Barbara Ercolano, M. J. Barlow, A. G. G. M. Tielens, Geoffrey C. Clayton, Albert A. Zijlstra, Margaret Meixner, Angela Speck, Tim M. Gledhill, Nino Panagia, Martin Cohen, Karl D. Gordon, Martin Meyer, Joanna Fabbri, Janet. E. Bowey, Douglas L. Welch, Michael W. Regan, and Robert C. Kennicutt, Jr.
Science 14 July 2006: 196-200.
Published online 8 June 2006 [DOI: 10.1126/science.1128131] (in Science Express Research Articles)
A 2003 supernova produced 10 times the dust seen after other such stellar explosions, implying that supernovae were dust factories in the early universe.
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Reports
Electric Fields at the Active Site of an Enzyme: Direct Comparison of Experiment with Theory
Ian T. Suydam, Christopher D. Snow, Vijay S. Pande, and Steven G. Boxer
Science 14 July 2006: 200-204.
The nitrile stretching frequency of an enzyme inhibitor reflects the effect of changes in the electric field of the enzyme抯 active site, which can greatly influence reactivity.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Negative Coulomb Drag in a One-Dimensional Wire
M. Yamamoto, M. Stopa, Y. Tokura, Y. Hirayama, and S. Tarucha
Science 14 July 2006: 204-207.
An electronic current in one nanowire produces a backward drag of electrons in a second one, providing evidence for the formation of an elusive one-dimensional Wigner crystal.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Atomic-Scale Control of Friction by Actuation of Nanometer-Sized Contacts
Anisoara Socoliuc, Enrico Gnecco, Sabine Maier, Oliver Pfeiffer, Alexis Baratoff, Roland Bennewitz, and Ernst Meyer
Science 14 July 2006: 207-210.
Friction between a sharp tip and a salt crystal was reduced when the tip was excited, a method that could decrease atomic stick-slip in nanoelectromechanical devices.
Abstract »| Full Text »| PDF »|
Dynamic Forces Between Two Deformable Oil Droplets in Water
Raymond R. Dagastine, Rogério Manica, Steven L. Carnie, D. Y. C. Chan, Geoffrey W. Stevens, and Franz Grieser
Science 14 July 2006: 210-213.
The behavior of emulsions depends on how individual droplets deform, how they interact, and how liquid drains between droplets, complicating models of these materials.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Tyrannosaur Life Tables: An Example of Nonavian Dinosaur Population Biology
Gregory M. Erickson, Philip J. Currie, Brian D. Inouye, and Alice A. Winn
Science 14 July 2006: 213-217.
Construction of a life history curve for a group of tyrannosaurs implies that about 70 percent of the young dinosaurs survived to become adults.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Crystal Structure of Glycoprotein B from Herpes Simplex Virus 1
Ekaterina E. Heldwein, Huan Lou, Florent C. Bender, Gary H. Cohen, Roselyn J. Eisenberg, and Stephen C. Harrison
Science 14 July 2006: 217-220.
Glycoprotein B from herpesvirus, a conserved component of the cell entry apparatus, has features of fusion proteins and is homologous to protein G from vesicular stomatitis virus.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
A Bacterial Virulence Protein Suppresses Host Innate Immunity to Cause Plant Disease
Kinya Nomura, Sruti DebRoy, Yong Hoon Lee, Nathan Pumplin, Jonathan Jones, and Sheng Yang He
Science 14 July 2006: 220-223.
A bacterial plant pathogen co-opts the target cell抯 own proteasome to degrade a defensive immunity protein used by the plant.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Evolution of Character Displacement in Darwin's Finches
Peter R. Grant and B. Rosemary Grant
Science 14 July 2006: 224-226.
Beak size in a finch Geospiza fortis on one Galápagos island diverged from that of a competitor (G. magnirostris) two decades after the latter抯 arrival.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Teaching in Wild Meerkats
Alex Thornton and Katherine McAuliffe
Science 14 July 2006: 227-229.
Adult wild meerkats train younger meerkats to kill prey by opportunity teaching, in which they provide pupils with the chance to practice skills in an interactive process.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Ca2+ Entry Through Plasma Membrane IP3 Receptors
Olivier Dellis, Skarlatos G. Dedos, Stephen C. Tovey, Taufiq-Ur-Rahman, Stefan J. Dubel, and Colin W. Taylor
Science 14 July 2006: 229-233.
Just two copies of an ion-conducting receptor in the membrane of immune cells can apparently contribute significantly to calcium entry after antigen stimulation.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Biomineralization of Gold: Biofilms on Bacterioform Gold
Frank Reith, Stephen L. Rogers, D. C. McPhail, and Daryl Webb
Science 14 July 2006: 233-236.
Bacteria that can cause precipitation of gold are found coating many secondary gold grains from Australian mines.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Selective Silencing of Foreign DNA with Low GC Content by the H-NS Protein in Salmonella
William Wiley Navarre, Steffen Porwollik, Yipeng Wang, Michael McClelland, Henry Rosen, Stephen J. Libby, and Ferric C. Fang
Science 14 July 2006: 236-238.
Published online 8 June 2006 [DOI: 10.1126/science.1128794] (in Science Express Reports)
Bacteria can recognize and silence invading foreign DNA by virtue of its lower overall GC content.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Technical Comments
Comment on "Ongoing Adaptive Evolution of ASPM, a Brain Size Determinant in Homo sapiens" and "Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans"
Mathias Currat, Laurent Excoffier, Wayne Maddison, Sarah P. Otto, Nicolas Ray, Michael C. Whitlock, and Sam Yeaman
Science 14 July 2006: 172.
Abstract »| Full Text »| PDF »|
Response to Comment on "Ongoing Adaptive Evolution of ASPM, a Brain Size Determinant in Homo sapiens" and "Microcephalin, a Gene Regulating Brain Size, Continues to Evolve Adaptively in Humans"
Nitzan Mekel-Bobrov, Patrick D. Evans, Sandra L. Gilbert, Eric J. Vallender, Richard R. Hudson, and Bruce T. Lahn
Science 14 July 2006: 172.
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