Bio2010 misinterpreted?     

Alberts B 《Science (New York, N.Y.)》2003,302(5650):1504

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The inimitable field of cosmology     

Railsback LB 《Science (New York, N.Y.)》2008,319(5864):726; author reply 726

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Scientific publishing standards     

Alberts B 《Science (New York, N.Y.)》2008,321(5894):1271

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The role of technology in enhancing low resource agriculture in Africa     

Bruce J. Horwith  Phyllis N. Windle  Edward F. MacDonald  J. Kathy Parker  Allen M. Ruby  Chris Elfring 《Agriculture and Human Values》1989,6(3):68-84

Traditional forms of farming, herding, and fishing are remarkably adapted to African conditions but these traditional approaches are being overtaken by modern pressures, particularly population growth. According to a report published by the Office of Technology Assessment (OTA), a nonpartisan analytical support agency of the U. S. Congress, one promising way to help African farmers and herders would be for development assistance organizations to focus more attention on the various forms of low-resource agriculture that predominate in Africa. In keeping with OTA's mission and primary audience, “Enhancing Agriculture in Africa: A Role for U. S. Development Assistance” (1988) is a policy-oriented synthesis of available technical information. The report provides Congress with a range of options that, if pursued, could help Africans enhance agriculture, increase their food security, and improve their lives. This paper is drawn from the larger OTA report, and it focuses on the role technology might play in enhancing low-resource agriculture. Readers should see the full assessment (OTA, 1988) for more information on policy considerations; the specific technologies mentioned; or a complete list of advisory panel members, workshops and participants, and commissioned papers. OTA's report comes at a critical time: for a variety of reasons—ranging from changing values to increased budget constraints—U. S. foreign assistance policy is undergoing a fundamental reevaluation. This review of the potential of low-resource agriculture, and options the United States might pursue to enhance this approach, was intended to aid in this reevaluation.  相似文献   

Operant conditioning of single-unit response patterns in visual cortex   总被引：1，自引：0，他引：1  

P G Shinkman  C J Bruce  B E Pfingst 《Science (New York, N.Y.)》1974,184(142):1194-1196

Unit responses to photic stimuli were studied in cat visual cortex. After the baseline response pattern of a cell was determined, conditioning trials were given during which reinforcement was contingent upon increased firing during a selected segment of the poststimulus interval. Density of reinforcement increased substantially in about half the cells studied; significant increases in firing occurred within, but not outside, the criterion segment.  相似文献   

Considering science education     

Alberts B 《Science (New York, N.Y.)》2008,319(5870):1589

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Band gap fluorescence from individual single-walled carbon nanotubes   总被引：1，自引：0，他引：1  

O'Connell MJ  Bachilo SM  Huffman CB  Moore VC  Strano MS  Haroz EH  Rialon KL  Boul PJ  Noon WH  Kittrell C  Ma J  Hauge RH  Weisman RB  Smalley RE 《Science (New York, N.Y.)》2002,297(5581):593-596

Fluorescence has been observed directly across the band gap of semiconducting carbon nanotubes. We obtained individual nanotubes, each encased in a cylindrical micelle, by ultrasonically agitating an aqueous dispersion of raw single-walled carbon nanotubes in sodium dodecyl sulfate and then centrifuging to remove tube bundles, ropes, and residual catalyst. Aggregation of nanotubes into bundles otherwise quenches the fluorescence through interactions with metallic tubes and substantially broadens the absorption spectra. At pH less than 5, the absorption and emission spectra of individual nanotubes show evidence of band gap-selective protonation of the side walls of the tube. This protonation is readily reversed by treatment with base or ultraviolet light.  相似文献   

THE ADVANCE IN OUR KNOWLEDGE OF THE CAUSATION AND METHODS OF PREVENTION OF STOCK DISEASES IN SOUTH AFRICA DURING THE LAST TEN YEARS     

Bruce D 《Science (New York, N.Y.)》1905,22(558):289-299

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Turkey and science academies     

Alberts B 《Science (New York, N.Y.)》2011,333(6051):1801

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Electrical energy storage for the grid: a battery of choices     

Dunn B  Kamath H  Tarascon JM 《Science (New York, N.Y.)》2011,334(6058):928-935

The increasing interest in energy storage for the grid can be attributed to multiple factors, including the capital costs of managing peak demands, the investments needed for grid reliability, and the integration of renewable energy sources. Although existing energy storage is dominated by pumped hydroelectric, there is the recognition that battery systems can offer a number of high-value opportunities, provided that lower costs can be obtained. The battery systems reviewed here include sodium-sulfur batteries that are commercially available for grid applications, redox-flow batteries that offer low cost, and lithium-ion batteries whose development for commercial electronics and electric vehicles is being applied to grid storage.  相似文献