| 2005年12月09日 Science中文摘要 | | 点击： 作者： 来源： 时间： 2006-11-12 本站论坛 |
|  | 2005年12月9日 美国《科学》周刊310卷 第5754期
大脑的情绪中心帮助处理不确定性
一个神经科学家和经济学家小组的研究发现，当一个人面临作有不确定性的决定时，大脑处理情绪的区域活跃起来。Ming Hsu和同事说，有关在缺少信息情况下作决定的大脑“硬连线”的新信息“很重要，因为这是每个社会层次的基本活动，包括人们为退休养老存钱，公司为保险定价，国家评价军事、社会、和环境风险”比如为气候变化或恐怖主义者袭击做准备。研究显示，与由于缺少信息而有不确定风险的不明确选择相比，人们比较容易地作出带有已知风险的决定。Hsu和同事将这些“风险与不确定性”决定用一个赌博游戏的形式提供给被测试者。研究人员用成像技术来观察他们作选择时的大脑活动，发现当被测试者面对不确定的决定时，两个情绪处理区域-杏仁核和眶额皮层-变得活跃。眶额皮层有病灶的患者不变现出选有风险而不是不确定的决定的正常选择，从而进一步提示了该区域在处理不确定性选择上的重要作用。本期一篇“研究评述”进一步讨论了这些发现。
报告：Neural Systems Responding to Degrees of Uncertainty in Human Decision-Making, Ming Hsu, Meghana Bhatt, Ralph Adolphs, Daniel Tranel, and Colin F. Camerer
研究评述：Emotion and Reason in Making Decisions, Aldo Rustichini
土地使用的改变与气候
一项新研究指出，将来为耕种和其他土地使用而砍伐森林的做法，给气候带来的影响超出大气温室气体和烟雾质的影响。Johannes Feddema和同事对本世纪可能的土地使用改变的不同情景做了气候变化的模拟。他们显示，未来土地使用的决定能改变气候变化的模拟。考虑到预测的由大气二氧化碳和温室气体带来的变暖，新研究提出，与土地覆盖有直接关系的区域性气候影响将主要发生在中纬度和热带地区。研究人员还指出，全球的平均温度受地面覆盖改变的影响不大，因为区域性对变暖的或多或少的影响趋于相互抵消。一篇相关的研究评述作者指出，此前，土地使用和土地覆盖变化和变异性对地区气候变量(区域温度、降水量、植被等) 的改变大多被忽略了。
报告：The Importance of Land-Cover Change in Simulating Future Climates, Johannes J. Feddema, et al.
研究评述：Land Use and Climate Change, Roger A. Pielke Sr.
神经递质与蛇的毒液
对蛇毒的麻醉成分的深入分析揭示了对突触神经递质释放调节的了解。意大利和英国的研究人员发现，一个脂肪酸和脂的混合物能模仿蛇毒神经毒素对神经递质释放的麻醉效果。人们知道被称为SPAN的蛇神经毒素能麻醉神经肌肉接头，导致神经肌肉接头中的运动神经末端扩张，诱导神经递质的释放。Michela Rigoni和同事现在发现，SPAN神经毒素作用于磷脂时释放的溶血磷脂和脂肪酸的一个混合物几乎能模仿SPAN所有的生物效果。一篇相关研究评述的作者指出，这项工作显示，脂施加给细胞膜双层的能量对膜的动力学至关重要。
报告：Equivalent Effects of Snake PLA2 Neurotoxins and Lysophospholipid-Fatty Acid Mixtures, Michela Rigoni, et al.
研究评述：Synaptic Membranes Bend to the Will of a Neurotoxin, Joshua Zimmerberg and Leonid V. Chernomordik
哺乳动物热量限制的基因基础
本期一篇简报指出，热量限制喂食的小鼠增加体力活动需要Sirt1基因，这是Sir2基因的哺乳动物版本，芽殖酵母和果蝇由热量限制带来的长寿需要有Sir2基因。这项工作为哺乳动物中热量限制作用的基因基础提供了初步的线索。热量限制现象在酵母、果蝇、线虫中已被深入地研究，热量限制使动物产生各种生理和行为的变化，从体力活动的增加到寿命的延长。但是，这些变化的基因基础在哺乳动物中还不太清楚。Danica Chen和同事发现，喂给正常小鼠通常食物量的60%使这些小鼠的活动增加。但是，缺少Sirt1基因的小鼠喂热量限制的饮食不增加活动量。研究人员说，“确定Sirt1基因是否调节其他热量限制的作用，比如延长寿命，将是有趣的工作。”
简报：Increase in Activity During Calorie Restriction Requires Sirt1, Danica Chen, Andrew D. Steele, Susan Lindquist, and Leonard Guarente
金属软化的机制
通常在金属中添加杂质使其硬化和强度增加，比如在铁中加碳使钢强硬。但对有些金属来说，杂质使其软化，钼就是这样的金属，这种金属材料可能是高温应用的重要结构材料，比如在涡轮机和核电厂部件中。但是金属在低温时变硬，这就不太容易改变其形状，也使其容易断裂，所以控制金属的软化对其在工业应用中的成功是关键。现在Dallas Trinkle和Christopher Woodward用一系列的计算机模型演示了为什么一个钼铼合金可能发生软化：铼的添加降低了位错运动的能量。金属中的位错越容易移动，该金属也变得越软。一篇相关的研究评述进一步讨论了这些发现。
报告：The Chemistry of Deformation: How Solutes Soften Pure Metals, Dallas R. Trinkle and Christopher Woodward
研究评述：Metallurgy in the Age of Silicon, D. C. Chrzan
银河系的英仙座旋臂离我们有多远？
研究人员完成了一项困难的工作：用三角视差法直接测量银河系的英仙座旋臂到太阳的距离。这项工作解决了用两种技术确定银河系大小的长期存在的差别。当地球绕太阳从轨道的一端转动到另一端时，近处的恒星相对更远的背景表现出一个微小的移动，这个现象被称为视差。徐烨和同事用一个名为甚长基线阵(Very Long Baseline Array)的10个射电望远镜系统测量了来自银河系英仙座旋臂中的一个年轻星团射电源的这个移动，从而准确地测出了银河系这个旋臂到太阳的距离。通过确定这个距离，研究人员显示，这个名为W3OH的星团的运动方式比简单地银河系旋转要复杂，这也许与旋密度波理论一致。
科学特快报告：The Distance to the Perseus Spiral Arm in the Milky Way, Y. Xu, M. J. Reid, X. W. Zheng, and K. M. Menten
This Week in Science
Editor summaries of this week's papers.
Science 9 December 2005: 1581.
|Full Text »
Editorial:
Battle for the Brains?
Hubert S. Markl
Science 9 December 2005: 1585.
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Editors' Choice
Highlights of the recent literature.
Science 9 December 2005: 1587.
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NetWatch
Best of the Web in science.
Science 9 December 2005: 1593.
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NEW PRODUCTS
Science 9 December 2005: 1691.
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News of the Week
SPACE SCIENCE: NASA Starts Squeezing to Fit Missions Into Tight Budget
Andrew Lawler
Science 9 December 2005: 1594-1595.
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STEM CELLS: Landmark Paper Has an Image Problem
Gretchen Vogel
Science 9 December 2005: 1595.
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INTELLECTUAL PROPERTY: Cambridge University Reins In Faculty Patents
Eliot Marshall
Science 9 December 2005: 1597.
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SPACE SCIENCE: Europe Trumpets Successes on Mars and Titan
Govert Schilling
Science 9 December 2005: 1598.
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BIOMEDICAL POLICY: U.K. Doubles Stem Cell Funding
Michael Schirber
Science 9 December 2005: 1599.
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EUROPEAN RESEARCH: ERC Moves Forward Despite Budget Impasse
Gretchen Vogel
Science 9 December 2005: 1599.
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NIH TRAINING GRANTS: Universities May Have to Pay More in Support of Graduate Training
Yudhijit Bhattacharjee
Science 9 December 2005: 1601.
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NIH CAREER AWARDS: Young Scientists Get a Helping Hand
Yudhijit Bhatttacharjee
Science 9 December 2005: 1601.
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ScienceScope
Science 9 December 2005: 1597.
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Random Samples
Science 9 December 2005: 1612.
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News Focus
INDIAN OCEAN TSUNAMI: Girding for the Next Killer Wave
Richard Stone and Richard A. Kerr
Science 9 December 2005: 1602-1605.
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INDIAN OCEAN TSUNAMI: A Dead Spot for the Tsunami Network?
Pallava Bagla
Science 9 December 2005: 1604.
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INDIAN OCEAN TSUNAMI: In the Wake: Looking for Keys to Posttraumatic Stress
Richard Stone
Science 9 December 2005: 1605.
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INFECTIOUS DISEASES: Will a Preemptive Strike Against Malaria Pay Off?
Gretchen Vogel
Science 9 December 2005: 1606-1607.
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INFECTIOUS DISEASES: Cracks in the First Line of Defense
Gretchen Vogel
Science 9 December 2005: 1607.
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NANOTECHNOLOGY: Calls Rise for More Research on Toxicology of Nanomaterials
Robert F. Service
Science 9 December 2005: 1609.
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ENERGY: For Nuclear Fusion, Could Two Lasers Be Better Than One?
Michael Schirber
Science 9 December 2005: 1610-1611.
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Letters
This Week's Letters
Science 9 December 2005: 1615.
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Support for the Human Cancer Genome Project
Harold Varmus and Bruce Stillman
Science 9 December 2005: 1615.
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Attribution of Disaster Losses
Roger A. Pielke Jr.; and Evan Mills
Science 9 December 2005: 1615-1616.
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Bilateral Action for Right Whales
Jesse S. Sayles, David M. Green;, Scott D. Kraus, Moira W. Brown, Christopher W. Clark, Philip K. Hamilton, Robert D. Kenney, Amy R. Knowlton, Scott Landry, Charles A. Mayo, William A. McLellan, Michael J. Moore, Douglas P. Nowacek, D. Ann Pabst, Andrew J. Read, and Rosalind M. Rolland
Science 9 December 2005: 1616-1618.
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Corrections and Clarifications
Science 9 December 2005: 1618.
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Books et al.
EVOLUTION: On the Origins of Novelty and Variation
Brian Charlesworth
Science 9 December 2005: 1619-1620.
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PHYSICS: Many Perspectives on Swinging
Alberto G. Rojo
Science 9 December 2005: 1620.
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Books Received
Science 9 December 2005: 1620.
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Policy Forum
AGRICULTURE: Losing the Links Between Livestock and Land
Rosamond Naylor, Henning Steinfeld, Walter Falcon, James Galloway, Vaclav Smil, Eric Bradford, Jackie Alder, and Harold Mooney
Science 9 December 2005: 1621-1622.
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Perspectives
MATERIALS SCIENCE: Metallurgy in the Age of Silicon
D. C. Chrzan
Science 9 December 2005: 1623-1624.
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NEUROSCIENCE: Emotion and Reason in Making Decisions
Aldo Rustichini
Science 9 December 2005: 1624-1625.
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ATMOSPHERIC SCIENCE: Land Use and Climate Change
Roger A. Pielke Sr.
Science 9 December 2005: 1625-1626.
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NEUROSCIENCE: Enhanced: Synaptic Membranes Bend to the Will of a Neurotoxin
Joshua Zimmerberg and Leonid V. Chernomordik
Science 9 December 2005: 1626-1627.
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Association Affairs
PRESIDENTIAL ADDRESS: The Nexus: Where Science Meets Society
Shirley Ann Jackson
Science 9 December 2005: 1634-1639.
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Reviews
Restoration of Degraded Tropical Forest Landscapes
David Lamb, Peter D. Erskine, and John A. Parrotta
Science 9 December 2005: 1628-1632.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Brevia
Increase in Activity During Calorie Restriction Requires Sirt1
Danica Chen, Andrew D. Steele, Susan Lindquist, and Leonard Guarente
Science 9 December 2005: 1641.
Mice usually increase their physical activity when fed a calorie-deficient diet, but not when they have a mutation in an aging-related protein.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Research Articles
The Kinase LKB1 Mediates Glucose Homeostasis in Liver and Therapeutic Effects of Metformin
Reuben J. Shaw, Katja A. Lamia, Debbie Vasquez, Seung-Hoi Koo, Nabeel Bardeesy, Ronald A. DePinho, Marc Montminy, and Lewis C. Cantley
Science 9 December 2005: 1642-1646.
Published online 22 November 2005 [DOI: 10.1126/science.1120781] (in Science Express Research Articles)
A key phosphorylating enzyme in the liver, which is required for the action of a diabetes drug, regulates glucose synthesis and blood levels.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
A Systems Model of Signaling Identifies a Molecular Basis Set for Cytokine-Induced Apoptosis
Kevin A. Janes, John G. Albeck, Suzanne Gaudet, Peter K. Sorger, Douglas A. Lauffenburger, and Michael B. Yaffe
Science 9 December 2005: 1646-1653.
A model of the interactions among cellular signaling components predicts previously unknown regulatory pathways for cell death.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Reports
Mach-Zehnder Interferometry in a Strongly Driven Superconducting Qubit
William D. Oliver, Yang Yu, Janice C. Lee, Karl K. Berggren, Leonid S. Levitov, and Terry P. Orlando
Science 9 December 2005: 1653-1657.
Published online 10 November 2005 [DOI: 10.1126/science.1119678] (in Science Express Reports)
A superconducting circuit can split a qubit state like a light beam, send each half on a separate path, and recombine them to produce quantum interference patterns.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Evidence for Macromolecular Protein Rings in the Absence of Bulk Water
Brandon T. Ruotolo, Kevin Giles, Iain Campuzano, Alan M. Sandercock, Robert H. Bateman, and Carol V. Robinson
Science 9 December 2005: 1658-1661.
Published online 16 November 2005 [DOI: 10.1126/science.1120177] (in Science Express Reports)
Protein-protein assemblies and protein-ligand complexes retain their overall structures during mass spectrometry, suggesting a new tool for structural determinations.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Rapid Chiral Assembly of Rigid DNA Building Blocks for Molecular Nanofabrication
R. P. Goodman, I. A. T. Schaap, C. F. Tardin, C. M. Erben, R. M. Berry, C. F. Schmidt, and A. J. Turberfield
Science 9 December 2005: 1661-1665.
Four single strands of DNA can be coaxed to self-assemble in seconds to form a rigid tetrahedron with defined stereochemistry, providing a module or template.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
The Chemistry of Deformation: How Solutes Soften Pure Metals
Dallas R. Trinkle and Christopher Woodward
Science 9 December 2005: 1665-1667.
Simulations show that impurities soften some body-centered cubic metals by making it easier for dislocations to move.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Rapid Glacial Erosion at 1.8 Ma Revealed by 4He/3He Thermochronometry
David L. Shuster, Todd A. Ehlers, Margaret E. Rusmoren, and Kenneth A. Farley
Science 9 December 2005: 1668-1670.
Glaciation increased the rate of incision of a Canadian alpine valley by at least a factor of six around 1.8 million years ago.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Hf-W Chronometry of Lunar Metals and the Age and Early Differentiation of the Moon
Thorsten Kleine, Herbert Palme, Klaus Mezger, and Alex N. Halliday
Science 9 December 2005: 1671-1674.
Published online 22 November 2005 [DOI: 10.1126/science.1118842] (in Science Express Reports)
The abundance of tungsten-182 in lunar metals implies that an extensive magma ocean on the moon solidified about 45 million years after formation of the solar system.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
The Importance of Land-Cover Change in Simulating Future Climates
Johannes J. Feddema, Keith W. Oleson, Gordon B. Bonan, Linda O. Mearns, Lawrence E. Buja, Gerald A. Meehl, and Warren M. Washington
Science 9 December 2005: 1674-1678.
Climate models show that expansion of agriculture into forests in the tropics or mid-latitudes could either enhance or retard warming regionally.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Equivalent Effects of Snake PLA2 Neurotoxins and Lysophospholipid-Fatty Acid Mixtures
Michela Rigoni, Paola Caccin, Steve Gschmeissner, Grielof Koster, Anthony D. Postle, Ornella Rossetto, Giampietro Schiavo, and Cesare Montecucco
Science 9 December 2005: 1678-1680.
The paralytic effects of a snake venom on neuromuscular synapses are mimicked by a mixture of fatty acids and lipids, suggesting its mechanism of action.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Neural Systems Responding to Degrees of Uncertainty in Human Decision-Making
Ming Hsu, Meghana Bhatt, Ralph Adolphs, Daniel Tranel, and Colin F. Camerer
Science 9 December 2005: 1680-1683.
People prefer choices with defined risk to those with ambiguous risk, but damage to the emotion-processing areas of the brain eliminates this preference.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
A Conserved Checkpoint Monitors Meiotic Chromosome Synapsis in Caenorhabditis elegans
Needhi Bhalla and Abby F. Dernburg
Science 9 December 2005: 1683-1686.
In nematodes, a newly recognized checkpoint prevents meiosis unless the homologous chromosomes are paired, and a second checkpoint validates proper recombination.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Snapshot of Activated G Proteins at the Membrane: The Gq-GRK2-Gß Complex
Valerie M. Tesmer, Takeharu Kawano, Aruna Shankaranarayanan, Tohru Kozasa, and John J. G. Tesmer
Science 9 December 2005: 1686-1690.
After hormonal stimulation, one of three subunits of a membrane-bound signaling protein dissociates and interacts with a target protein to activate it.
Abstract »| Full Text »| PDF »| Supporting Online Material »|
Technical Comments
Comment on "How Science Survived: Medieval Manuscripts' `Demography' and Classic Texts' Extinction"
Georges Declercq
Science 9 December 2005: 1618.
Abstract »| Full Text »| PDF »|
Response to Comment on "How Science Survived: Medieval Manuscripts' `Demography' and Classic Texts' Extinction"
John L. Cisne
Science 9 December 2005: 1618.
Abstract »| Full Text »| PDF »|
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