Tạp chí khoa học số 2005-01-28

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28 January 2005 Vol. 307 No. 5709 Pages 465–628 $10 Traditional Mini Preps are Over. Stop Manual Mini Preps Start the Mini Prep 96 TM 1-800-466-7949 www.macconnell.com Mini-Preps at the Push of a Button. 6195 Cornerstone Court, San Diego, California 92121, Fax: 858-452-6753 Start automating with the latest in plasmid DNA purification. The Mini Prep 96 can perform up to 96 preps in 1 hour of processing time. Up to 8 µg of plasmid DNA per lane at less than $1 a prep. Start with easy operation. Disposable cassettes allow for direct loading of culture with no centrifugation. Start the Mini Prep 96 with the push of a button. Remove high purity DNA and use in most microbiology protocols — including sequencing and cell transfection. Start saving time and money with the Mini Prep 96. Four Easy Steps to Plasmid DNA Purification www.RnDSystems.com | (800) 343-7475 Quality | Selection | Performance | Results North America R&D Systems, Inc. Tel: (800) 343-7475 info@RnDSystems.com Europe R&D Systems Europe Ltd. Tel: 0800 37 34 15 info@RnDSystems.co.uk Germany R&D Systems GmbH Tel: 0800 909 4455 infogmbh@RnDSystems.co.uk France R&D Systems Europe Tel: 0800 90 72 49 info@RnDSystems.co.uk 2005 Catalog from R&D Systems R&D Systems 2005 catalog is now available. Our up-to-date, compre- hensive product listing includes a broad selection of over 7,000 products for cancer, development, endocrinology,immunology, neuroscience, protease, and stem cell research. Please call or go online to request your copy today. Each catalog comes with our T Cell-mediated Cytotoxicity poster, featur- ing the new catalog art. Ettan ™ MDLC is GE Healthcare’s latest liquid chromatography system for proteomics applications. The system’s patented nano-valve design provides ultra-low dead volumes for multidimensional and nanoscale peptide separation, resulting in unrivaled resolution and reproducibility. This flexible and bioinert system lets you choose between dedicated high- throughput 1D-LC, online or offline 2D-LC configurations depending on your sample complexity. Its unmatched level of resolution enables you to maximize the performance of your mass spectrometer. Visit www.mdlc.com Focus on the highest level of peptide resolution. Part of GE Healthcare © 2004 General Electric Company - All rights reserved. Amersham Biosciences UK Ltd, a General Electric company, going to market as GE Healthcare. GE02-05 www.sciencemag.org SCIENCE VOL 307 28 JANUARY 2005 469 DEPARTMENTS 475 SCIENCE ONLINE 477 THIS WEEK IN SCIENCE 481 EDITORIAL by Rodger W. Bybee and Donald Kennedy Math and Science Achievement 483 E DITORS’CHOICE 488 CONTACT SCIENCE 491 NETWATCH 537 AAAS NEWS AND NOTES 605 NEW PRODUCTS 610 SCIENCE CAREERS NEWS OF THE WEEK 492 DIVERSITY Summers’s Comments Draw Attention to Gender, Racial Gaps 493 V IROLOGY One Virus, Three Names, Three Claims 495 C HEMISTRY Shape-Shifting Catalyst Lights Way to New Strategy for Detecting Chemicals 495 S CIENCESCOPE 496 CLIMATE CHANGE Panel Urges Unified Action, Sets 2° Target 496 P LANETARY SCIENCE Missing Noble Gases Hint How Titan Got Its Dense Atmosphere 497 G REENHOUSE WARMING Climate Modelers See Scorching Future as a Real Possibility 498 A GRICULTURAL RESEARCH Centers Embrace an Alliance But Remain Wary of a Merger 498 NASA B UDGET Hubble, Other Programs Face Cuts in 2006 499 H IGHER EDUCATION Fundraising Begins for Network of Four African Institutes 499 R ESEARCH FUNDING Saudi Millionaire Plans an NSF for Arab Scientists 501 B IODEFENSE LABS Boston University Under Fire for Pathogen Mishap 501 C LIMATE CHANGE Scientist Quits IPCC Panel Over Comments NEWS FOCUS 502 SOUTH ASIA TSUNAMI A Race to Beat the Odds Nuke Policy Leads India to Build Own Network DNA Helps Identify Missing in the Tsunami Zone 505 EVOLUTION Dover Teachers Want No Part of Intelligent- Design Statement 507 E NVIRONMENTAL HEALTH Debate Continues Over Safety of Water Spiked With Rocket Fuel 508 M EETING American Astronomical Society Galaxy Patterns Preserve an Imprint of the Big Bang Satellite Swiftly Catches New Bursts An Origin for the Fiercest Cosmic Rays? Snapshots From the Meeting 511 RANDOM SAMPLES LETTERS 515 Marburger Makes His Position Clear J. H. Marburger III. The Ethics of Deriving Gametes from ES Cells A. Lippman and S.A. Newman. Response G. Testa and J. Harris. Costs of a Rotavirus Vaccine J.Wecker. Preserving an Important Collection N. Zinder and R. J. Roberts. Science and the Bush Administration J. C. Gruman 519 Corrections and Clarifications BOOKS ET AL. 520 VERTEBRATE PALEONTOLOGY The Dinosauria 2nd ed. D. B.Weishampel, P. Dodson, H. Osmólska, Eds., reviewed by H. C. E. Larsson 521 COMPUTING The SIAM 100-Digit Challenge A Study in High-Accuracy Numerical Computing F. Bornemann, D. Laurie, S.Wagon, J. Waldvogel, reviewed by G. Strang 522 HISTORY OF SCIENCE Pandora’s Breeches Women, Science and Power in the Enlightenment P. Fara, reviewed by A. Gopinathan POLICY FORUM 525 ECOLOGY Do the Largest Protected Areas Conserve Whales or Whalers? L. R. Gerber, K. D. Hyrenbach, M. A. Zacharias Contents continued COVER Artist’s cutaway view through a live cell and its nucleus, showing components of a signaling pathway labeled with quantum dots of different colors (spheres). The long fluorescence lifetimes of quantum dots (semiconductor nanocrystals) will enable visualization of signal transduction pathways in real time. See page 538. [Image: Darren Keogh] 525 Volume 307 28 January 2005 Number 5709 502 505 The BioRobot ® Gene Expression system automates the preparation of targets for Affymetrix ® GeneChip arrays for more reproducible data! Standardized target preparation is of critical importance for precise GeneChip array results. Streamline your workflow and increase reproducibility with the BioRobot Gene Expression system and Specialist Pack for GeneChip target preparation! ■ More precise array results — through standardized target preparation, from cDNA synthesis to cRNA fragmentation ■ Reduced hands-on time — with streamlined, automated workflow ■ Comprehensive support — including installation, training, chemistries starter pack, and software protocols Trademarks: QIAGEN ® , BioRobot ® (QIAGEN Group); Affymetrix ® , GeneChip ® (Affymetrix, Inc.). QIAGEN robotic systems are not available in all countries; please inquire. IASBRTP0105S1WW 12/2004 © 2004 QIAGEN, all rights reserved. Integrated Solutions — Gene Expression Analysis Standardize your target preparation for more precise GeneChip ® array results! WWW.QIAGEN.COM Visit us at www.qiagen.com/automation and discover the standardized solution for precise GeneChip array results! 0 20 40 60 80 100 12 3 4567 8 9101112 Column number cRNA yield (µg) Average yield of cRNA from 96 RNA samples from HeLa S3 cells Automated target preparation Good correlation with manual target preparation procedure www.sciencemag.org SCIENCE VOL 307 28 JANUARY 2005 471 PERSPECTIVES 527 EVOLUTION An Eocene Big Bang for Bats N. B. Simmons related Report page 580 528 PARASITOLOGY Malaria Vaccines: Back to the Future? A. P. Waters et al. 530 P HYSIOLOGY A NEAT Way to Control Weight? E. Ravussin related Report page 584 531 PHYSICS How to Create a Spin Current P. Sharma 533 ASTRONOMY The Hunt for Intermediate-Mass Black Holes G. Fabbiano REVIEW 538 BIOCHEMISTRY Quantum Dots for Live Cells, in Vivo Imaging, and Diagnostics X. Michalet et al. S CIENCE EXPRESS www.sciencexpress.org PLANT SCIENCE: BZR1 Is a Transcriptional Repressor with Dual Roles in Brassinosteroid Homeostasis and Growth Responses J X. He, J. M. Gendron, Y. Sun, S. S. L. Gampala, N. Gendron, C. Q. Sun, Z Y.Wang A newly described transcription factor regulates both the biosynthesis of a steroid hormone in plants and how that hormone controls growth. NEUROSCIENCE: Control of Excitatory and Inhibitory Synapse Formation by Neuroligins B. Chih, H. Engelman, P. Scheiffele A cell surface protein coordinates the process by which two neurons form a synapse, triggering spine formation and specifying protein accumulation. BIOCHEMISTRY: Membrane Insertion of a Potassium-Channel Voltage Sensor T. Hessa, S. H.White, G. von Heijne Although it is highly charged, the voltage-sensing portion of the potassium channel can move easily through the lipid bilayer to open the channel. PHYSICS: Heat Capacity of a Strongly Interacting Fermi Gas J. Kinast,A.Turlapov, J. E. Thomas, Q. Chen, J. Stajic, K. Levin A change in heat capacity of supercooled lithium atoms marks the transition between a Bose-Einstein state with strongly paired atoms and a more weakly paired superfluid state. BREVIA 545 CELL BIOLOGY: Marine Fish Egg Hydration Is Aquaporin-Mediated M. Fabra, D. Raldúa, D. M. Power, P. M.T. Deen, J. Cerdà A water channel on the surface of fish eggs allows hydration that ensures proper buoyancy of the egg for dispersal in the ocean. RESEARCH ARTICLES 546 PLANETARY SCIENCE: A Giant Impact Origin of Pluto-Charon R. M. Canup Charon, Pluto’s moon, may have formed when Pluto received a grazing blow from another large icy body, implying that large early collisions affected the outer solar system. 550 ECOLOGY: Farming and the Fate of Wild Nature R. E. Green, S. J. Cornell, J. P.W. Scharlemann, A. Balmford A model determines the consequences for wildlife of the trade-off between yield intensity of land under cultivation and amount of land under cultivation. REPORTS 555 CHEMISTRY: Ammonia Synthesis from First-Principles Calculations K. Honkala et al. Calculations relating the rate of ammonia synthesis to the size distribution of ruthenium catalyst nanoparticles aid in the design of this catalyst. 558 CHEMISTRY: Dark Structures in Molecular Radiationless Transitions Determined by Ultrafast Diffraction R. Srinivasan, J. S. Feenstra, S. T. Park, S. Xu,A. H. Zewail Electron diffraction reveals how organic molecules excited by light release energy through a series of structural changes induced by electronic and vibrational motions. Contents continued 558 528 www.sciencemag.org SCIENCE VOL 307 28 JANUARY 2005 473 590 563 ATMOSPHERIC SCIENCE: Electron Spectroscopy of Aqueous Solution Interfaces Reveals Surface Enhancement of Halides S. Ghosal et al. Halides, particularly the larger ones, become concentrated at the surface of liquid salt droplets, enhancing their reactivity in Earth’s atmosphere. 566 PLANETARY SCIENCE: Nightglow in the Upper Atmosphere of Mars and Implications for Atmospheric Transport J L. Bertaux et al. Glowing, nighttime nitric oxide emissions, detected by Mars Express, track the descent of high air masses during winter above the martian south pole. 569 MATERIALS SCIENCE: Prediction of Hydrogen Flux Through Sulfur-Tolerant Binary Alloy Membranes P. Kamakoti, B. D. Morreale, M.V. Ciocco, B. H. Howard, R. P. Killmeyer, A.V. Cugini, D. S. Sholl Ab initio calculations accurately predict how hydrogen diffuses through metal alloy membranes and could improve hydrogen purification. 573 PLANT SCIENCE: Micropylar Pollen Tube Guidance by Egg Apparatus 1 of Maize M. L. Márton, S. Cordts, J. Broadhvest, T. Dresselhaus In flowering plants, a newly identified peptide signal guides the sperm cell–containing pollen tube to the egg for fertilization. 576 EVOLUTION: A Brief History of Seed Size A. T. Moles, D. D. Ackerly, C. O.Webb, J. C. Tweddle, J. B. Dickie, M.Westoby A comprehensive seed survey shows that the evolutionarily older gymnosperms have larger seeds than flowering plants but that larger flowering plants have larger seeds. 580 EVOLUTION: A Molecular Phylogeny for Bats Illuminates Biogeography and the Fossil Record E. C. Teeling, M. S. Springer, O. Madsen, P.Bates, S. J. O’Brien,W. J. Murphy New sequence data supplements an incomplete fossil record to predict a phylogeny for all living bats, identifying four groups of microbats and a likely origin in North America. related Perspective page 527 584 PHYSIOLOGY: Interindividual Variation in Posture Allocation: Possible Role in Human Obesity J.A. Levine et al. During their daily lives, lean people spend less time sitting than do people who are overweight, even after the former have purposefully gained weight. related Perspective page 530 586 MOLECULAR BIOLOGY: Sequence-Directed DNA Translocation by Purified FtsK P. J. Pease, O. Levy, G. J. Cost, J. Gore, J. L. Ptacin, D. Sherratt, C. Bustamante, N. R. Cozzarelli Individual DNA translocase molecules zip along single strands of DNA at 5 kilobases per second and reverse without dissociation upon encountering certain asymmetric sequences. 590 IMMUNOLOGY: Restoration of Tolerance in Lupus by Targeted Inhibitory Receptor Expression T. L. McGaha, B. Sorrentino, J.V. Ravetch Simply increasing the number of inhibitory receptors on immune cells prevents mice from developing an apparently complicated autoimmune disorder similar to lupus. 593 IMMUNOLOGY: Endogenous MHC Class II Processing of a Viral Nuclear Antigen After Autophagy C. Paludan, D.Schmid, M. Landthaler, M.Vockerodt, D. Kube, T.Tuschl, C. Münz An endogenous nuclear antigen can be presented by a pathway thought to be restricted to antigens derived from exogenous, internalized sources. 596 DEVELOPMENTAL BIOLOGY: Small CTD Phosphatases Function in Silencing Neuronal Gene Expression M. Yeo, S K. Lee, B. Lee, E. C. Ruiz, S. L. Pfaff, G. N. Gill Cells outside the brain guard against becoming neurons by expressing an enzyme that modifies RNA polymerase in a way that prevents it from transcribing neural genes. 600 NEUROSCIENCE: Illumination of the Melanopsin Signaling Pathway S. Panda, S. K. Nayak, B. Campo, J. R. Walker, J. B. Hogenesch,T. Jegla In mammals, the opsin that detects light for circadian rhythms and pupil constriction activates signaling pathways that are similar to those used in invertebrates for vision. SCIENCE (ISSN 0036-8075) is published weekly on Friday, except the last week in December, by the American Association for the Advancement of Science, 1200 New York Avenue, NW,Washington, DC 20005. Periodicals Mail postage (publication No. 484460) paid at Washington, DC, and additional mailing offices. Copyright © 2005 by the American Association for the Advancement of Science.The title SCIENCE is a registered trademark of the AAAS. Domestic individual membership and subscription (51 issues): $135 ($74 allocated to subscription). Domestic institutional subscription (51 issues): $550; Foreign postage extra: Mexico, Caribbean (surface mail) $55; other countries (air assist delivery) $85. First class, airmail, student, and emeritus rates on request. Canadian rates with GST available upon request, GST #1254 88122. Publications Mail Agreement Number 1069624. Printed in the U.S.A. Change of address: allow 4 weeks, giving old and new addresses and 8-digit account number. Postmaster: Send change of address to Science, P.O. Box 1811, Danbury, CT 06813–1811. Single copy sales: $10.00 per issue prepaid includes surface postage; bulk rates on request. Authorization to photocopy material for internal or personal use under circumstances not falling within the fair use provisions of the Copyright Act is granted by AAAS to libraries and other users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service, provided that $15.00 per article is paid directly to CCC, 222 Rosewood Drive, Danvers, MA 01923. The identification code for Science is 0036-8075/83 $15.00. Science is indexed in the Reader’s Guide to Periodical Literature and in several specialized indexes. Contents continued REPORTS CONTINUED 566 Visit us on the Web at discover.bio-rad.com Call toll free at 1-800-4BIORAD (1-800-424-6723); outside the US, contact your local sales office. A Sea of Amplification Options A complete selection of amplification reagents for both real-time and conventional PCR ■ Enzymes and kits for a broad array of applications — hot-start PCR, reverse transcription, and real-time PCR using SYBR Green or probe-based detection ■ High-quality reagents designed for convenience — easy-to-use kits and protocols simplify reaction setup to generate consistent, reproducible results ■ Products developed and supported by amplification experts — formulated to provide sensitive detection and linear data over a wide dynamic range To learn more about PCR and the results you can obtain, visit us on the Web at www.bio-rad.com/ad/ampreagents/ AMPLIFICATION REAGENTS Practice of the patented polymerase chain reaction (PCR) process requires a license. SYBR is a trademark of Molecular Probes, Inc. Bio-Rad Laboratories, Inc. is licensed by Molecular Probes, Inc. to sell reagents containing SYBR Green I for use in real-time PCR for research purposes only. . reserved. Amersham Biosciences UK Ltd, a General Electric company, going to market as GE Healthcare. GE02-05 www.sciencemag.org SCIENCE VOL 307 28 JANUARY 2005 469 DEPARTMENTS 475 SCIENCE ONLINE 477. IN SCIENCE 481 EDITORIAL by Rodger W. Bybee and Donald Kennedy Math and Science Achievement 483 E DITORS’CHOICE 488 CONTACT SCIENCE 491 NETWATCH 537 AAAS NEWS AND NOTES 605 NEW PRODUCTS 610 SCIENCE. Green I for use in real-time PCR for research purposes only. 475 www.sciencemag.org SCIENCE VOL 307 28 JANUARY 2005 sciencenow www.sciencenow.org DAILY NEWS COVERAGE Viagra for Broken Hearts? Early

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