Tạp chí khoa học số 2006-05-05

5 May 2006 | $10 A MPLIF ICATION CELL B IOLOG Y C LONING MIC ROA RRA YS NUC LE ICACID A NA LYSIS PROTEIN FUNCTION & ANALYSIS QUA NTITA TIVE PC R SOF TWA RE SOLUTIONS Ask Us About These Great Products: Our new StrataScript ® 5.0 Multi-Temperature Reverse Transcriptase (RT) delivers high cDNA yield over a broader cDNA synthesis temperature range (37–60°C). This unique, multi-temperature capability allows you to use the optimal reaction temperature for your template and primers without having to change your reverse transcriptase. Achieve 10-fold greater yield of amplifiable cDNA from lower RNA input levels and up to four-fold better yields of full-length cDNA. StrataScript ® 5.0 Multi-Temperature Reverse Transcriptase 2,000U 600098 10,000U 600100 SuperScript ® III 42 50 55 60 42 50 55 60 42 50 55 60 6.0 kb 4.0 kb 2.0 kb 1.0 kb 9.0 kb 5.0 kb 3.0 kb 1.5 kb 0.5 kb Temp (°C) StrataScript ® 5.0 RT SuperScript ® II Don’t let temperature hold you back. Only StrataScript ® 5.0 RT delivers reliable results at any temperature. Choose the Temperature You Need Need More Information? Give Us A Call: Stratagene US and Canada Order: 800-424-5444 x3 Technical Service: 800-894-1304 x2 Stratagene Japan K.K. Order: 3-5821-8077 Technical Service: 3-5821-8076 www.stratagene.com Stratagene Europe Order: 00800-7000-7000 Technical Service: 00800-7400-7400 StrataScript ® is a registered trademark of Stratagene in the United States. SuperScript ® is a registered trademark of Invitrogen Corp. Patents pending. GE Healthcare HiTrap ™ columns give you pure proteins with less effort. They come prepacked with the widest choice of media, ensuring results you can depend on in a broad range of applications, and the highest level of convenience. But we’re never content to stand still. We constantly strive for new innovations for tomorrow’s research and drug development. And thanks to our technological achievements and global presence, we’re able to help you turn your scientific ideas into reality – bringing science to life and helping transform healthcare. We call it Life Science Re-imagined. Discover how HiTrap columns can help power your protein purification. Visit www.gehealthcare.com/life Faster protein purification? It’s not rocket science. GE Healthcare Bio-Sciences AB, a General Electric Company. Björkgatan 30, 751 84 Uppsala, Sweden. © 2006 General Electric Company - All rights reserved. GE05-06 www.dowellstubbs.com www.sciencemag.org SCIENCE VOL 312 5 MAY 2006 645 CONTENTS CONTENTS continued >> NEWS OF THE WEEK Texas Earmark Allots Millions to Disputed Theory of 668 Gulf War Illness Genes and Chronic Fatigue: How Strong Is the 669 Evidence? Industry Shrinks Academic Support 671 SCIENCESCOPE 671 A New Way to Beat the Limits on Shrinking Transistors? 672 Differences in Immune Cell “Brakes” May Explain 672 Chimp-Human Split on AIDS Despite Mutated Gene, Mouse Circadian Clock Keeps 673 on Ticking Industry Conservation Programs Face White House Cuts 675 NEWS FOCUS A Tempestuous Birth for Hurricane Climatology 676 Indian Angst Over Atomic Pact 679 The Map in the Brain: Grid Cells May Help Us Navigate 680 >> Report p. 758 Tipping the Scales—Just Barely 683 Rising From the Ashes 684 DEPARTMENTS 651 Science Online 653 This Week in Science 659 Editors’ Choice 662 Contact Science 665 NetWatch 667 Random Samples 687 Newsmakers 763 New Products 770 Science Careers COVER A snapshot from computer simulations of the collision of two neutron stars, about 3 milliseconds after impact. Spiral arms form as the stars shred each other by their strong tidal forces. The colors represent the strength of the magnetic fields produced in the merger, here already amplified in the central regions to values exceeding any previously known in the universe (yellow-white regions). See page 719. Image: D. J. Price and S. Rosswog EDITORIAL 657 The High Cost of Coming to America by Al Teich and Wendy D. White 676 LETTERS Debating Sexual Selection and Mating Strategies 689 S. R. X. Dall, J. M. McNamara, N. Wedell, D. J. Hosken; C. M. Lessells et al.; T. Pizzari et al.; D. M. Buss; T. Day, D. Houle, L. Rowe; M. T. Ghiselin; P. L. Hurd; G. Miller; D. M. Shuker and T. Tregenza; J. Stewart Response J. Roughgarden, E. Akçay, M. Oishi CORRECTIONS AND CLARIFICATIONS 697 BOOKS ET AL. How Fat Works 698 P. A. Wood, reviewed by J. M. Ntambi Intuition A Novel 698 A. Goodman, reviewed by D. T. Scholes >> ScienceCareers.org story by B. Benderly BROWSINGS 699 POLICY FORUM Harmonization of Animal Care and Use Guidance 700 G. Demers et al. PERSPECTIVES Linear Dunes on Titan 702 N. Lancaster >> Report p. 724 Shuttling Polyolefins to a New Materials Dimension 703 V. C. Gibson >> Research Article p. 714 The Pleasures and Pains of Information 704 G. Loewenstein >> Report p. 754 The Primordial Porridge 706 B. Marty >> Report p. 727 Follow the Nitrogen 708 D. G. Capone, R. Popa, B. Flood, K. H. Nealson B Cells Spread and Gather 709 M. M. Harnett >> Report p. 738 Nicholas J. Shackleton (1937–2006) 711 W. F. Ruddiman Volume 312, Issue 5774 Advance your gene expression research with standardized solutions for RNA purification! QIAGEN RNA solutions standardize the purification of RNA from biological samples. Benefits include: ■ Reliability — highly pure, intact RNA for standardized results in all downstream applications ■ Convenience — easy-to-use kits with minimal protocol steps ■ Speed — ready-to-use RNA purified in as little as 25 minutes ■ Versatility — manual and automated kits for a wide range of sample types, sizes, and throughputs For up-to-date trademarks and disclaimers, see www.qiagen.com . GEXRNA0106S1WW © 2006 QIAGEN, all rights reserved. Systems Biology — RNA Purification Standardized RNA solutions guarantee comparable results WWW.QIAGEN.COM 10 20 30 40 50 60 70 0 2419 29 34 39 44 49 54 59 64 Purification of high-quality RNA Convenient RNA purification Visit www.qiagen.com/goto/RNAsolutions to find out more! www.sciencemag.org SCIENCE VOL 312 5 MAY 2006 647 CONTENTS continued >> CONTENTS 703 & 714 BREVIA ATMOSPHERIC SCIENCE Environmental Monitoring by Wireless 713 Communication Networks H. Messer, A. Zinevich, P. Alpert A real-time map of rainfall intensity can be recovered by measuring the attenuation in signals from cell phones in a network. RESEARCH ARTICLE CHEMISTRY Catalytic Production of Olefin Block Copolymers 714 via Chain Shuttling Polymerization D. J. Arriola et al. A molecule that shuttles growing polymers back and forth between two catalysts to produce a segmented chain allows high efficiency and fine control of the polymers’ elastic properties. >> Perspective p. 703 SCIENCE EXPRESS www.sciencexpress.org ASTRONOMY Why the Cosmological Constant Is Small and Positive P. J. Steinhardt and N. Turok Models in which our universe repeatedly grows from a big bang and then collapses produce a small cosmological constant consistently, not only as a special case. >> Science Express Perspective by A. Vilenkin 10.1126/science.1126231 PERSPECTIVE: The Vacuum Energy Crisis A. Vilenkin >> Science Express Research Article by P. J. Steinhardt and N. Turok 10.1126/science.1128570 STRUCTURAL BIOLOGY Structure of the Eukaryotic Thiamine Pyrophosphate Riboswitch with Its Regulatory Ligand S. Thore, M. Leibundgut, N. Ban The structure of a common metabolite bound to a ubiquitous riboswitch shows how its ligand turns it off, suppressing translation of genes for the metabolite’s synthesis. 10.1126/science.1128451 REPORTS ASTROPHYSICS Producing Ultrastrong Magnetic Fields in 719 Neutron Star Mergers D. J. Price and S. Rosswog Simulations of the merging of a neutron star binary pair show that magnetic fields can be amplified strongly and quickly, before the stars collapse to form a black hole. CHEMISTRY Cyclopropenylidenes: From Interstellar Space to 722 an Isolated Derivative in the Laboratory V. Lavallo et al. The triangular C 3 H 2 molecule, which appears to be stable only in the near-vacuum of interstellar space, has been isolated by appending amino groups to the ring. PLANETARY SCIENCE The Sand Seas of Titan: Cassini RADAR Observations 724 of Longitudinal Dunes R. D. Lorenz et al. Radar images of Saturn’s moon Titan show that large regions of its surface are covered in dunes up to 150 meters high, produced by regular winds acting on sand-sized grains. >> Perspective p. 702 GEOCHEMISTRY Interstellar Chemistry Recorded in Organic Matter 727 from Primitive Meteorites H. Busemann et al. Hydrogen and nitrogen isotopes in organic matter of primitive meteorites suggest that much of this material is unaltered and formed in the cold presolar nebula, not later. >> Perspective p. 706 PLANT SCIENCE CO/FT Regulatory Module Controls Timing of Flowering and Seasonal Growth Cessation in Trees H. Böhlenius et al. Poplar, a perennial tree, contains genes controlling flowering and the onset of dormancy that are homologs of flowering time genes in Arabidopsis. 10.1126/science.1126038 © 2006 Perlegen “I think the dosage needs adjusting. I’m not nearly as happy as the people in the ads.” What if you could use DNA to identify patients who respond well to your drug? You might use that knowledge to reach more patients and expand your market, or to get a drug to market faster. Either way – patients win. Perlegen is helping drug companies do just that – today. Working with you, we can comprehensively analyze the DNA from hundreds of patients taking your drug. Out of the millions of genetic variations between patients, we help you identify the ones that are associated with strong efficacy, poor efficacy, or side effects. Perlegen’s unparalleled coverage of the genome and experienced team of analysts mean you get clinically relevant answers, not just data, in a matter of months. We partner with the top pharmaceutical companies around the world. We also license late-stage drugs. If you have a drug that can benefit from our approach, please contact us. Patients are waiting. genetics@perlegen.com Mountain View, California • 650-625-4500 Tokyo, Japan • +81 (0)3 3444-6080 www.perlegen.com Targeting today’s drugs. Discovering tomorrow’s. TM It’s time for genetics. © The New Yorker Collection 2001 Barbara Smaller from cartoonbank.com. All Rights Reserved. . Wendy D. White 10.1126 /science. 1127775 Al Teich is director of Science and Policy Programs at the American Association for the Advancement of Science. www.sciencemag.org SCIENCE VOL 312 5 MAY. gels separate more samples and yield great results. 8.7 cm www.sciencemag.org SCIENCE VOL 312 5 MAY 2006 651 ONLINE SCIENCENOW www.sciencenow.org DAILY NEWS COVERAGE Mineral Time Capsules on Mars? Organic. Ashes 684 DEPARTMENTS 651 Science Online 653 This Week in Science 659 Editors’ Choice 662 Contact Science 665 NetWatch 667 Random Samples 687 Newsmakers 763 New Products 770 Science Careers COVER A