Mathematics and biology. A bright future for biologists and mathematicians?     

Hastings A  Palmer MA 《Science (New York, N.Y.)》2003,299(5615):2003-2004

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Detection of a red supergiant progenitor star of a type II-plateau supernova     

Smartt SJ  Maund JR  Hendry MA  Tout CA  Gilmore GF  Mattila S  Benn CR 《Science (New York, N.Y.)》2004,303(5657):499-503

We present the discovery of a red supergiant star that exploded as supernova 2003gd in the nearby spiral galaxy M74. The Hubble Space Telescope (HST) and the Gemini Telescope imaged this galaxy 6 to 9 months before the supernova explosion, and subsequent HST images confirm the positional coincidence of the supernova with a single resolved star that is a red supergiant of 8(+4)(-2) solar masses. This confirms both stellar evolution models and supernova theories predicting that cool red supergiants are the immediate progenitor stars of type II-plateau supernovae.  相似文献   

Conservation. Caffeine and conservation     

O'Brien TG  Kinnaird MF 《Science (New York, N.Y.)》2003,300(5619):587

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Science, technology, and some dilemmas of advocacy     

Adams M 《Science (New York, N.Y.)》1973,180(4088):840-842

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Ethics: a weapon to counter bioterrorism     

Somerville MA  Atlas RM 《Science (New York, N.Y.)》2005,307(5717):1881-1882

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Would Title IX help women in science?     

Smither-Kopperl ML 《Science (New York, N.Y.)》2002,298(5600):1891-1892

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Failure of bone marrow cells to transdifferentiate into neural cells in vivo     

Castro RF  Jackson KA  Goodell MA  Robertson CS  Liu H  Shine HD 《Science (New York, N.Y.)》2002,297(5585):1299

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Legionella effectors that promote nonlytic release from protozoa     

Chen J  de Felipe KS  Clarke M  Lu H  Anderson OR  Segal G  Shuman HA 《Science (New York, N.Y.)》2004,303(5662):1358-1361

Legionella pneumophila, the bacterial agent of legionnaires' disease, replicates intracellularly within a specialized vacuole of mammalian and protozoan host cells. Little is known about the specialized vacuole except that the Icm/Dot type IV secretion system is essential for its formation and maintenance. The Legionella genome database contains two open reading frames encoding polypeptides (LepA and LepB) with predicted coiled-coil regions and weak homology to SNAREs; these are delivered to host cells by an Icm/Dot-dependent mechanism. Analysis of mutant strains suggests that the Lep proteins may enable the Legionella to commandeer a protozoan exocytic pathway for dissemination of the pathogen.  相似文献   

Renovating dependency and self-reliance for participatory sustainable development     

Nancy Grudens-Schuck  Will Allen  Tasha M. Hargrove  Margaret Kilvington 《Agriculture and Human Values》2003,20(1):53-64

Dependency stands for manygrievances and is generally considered asymptom of oppression. An opposing concept,offered as the preferred state, isself-reliance. Dependency and self-reliance arekey concepts in sustainable developmentprograms that feature participatory approaches.Some of the ways in which development projectsemploy the concepts of dependency andself-reliance, however, are troubling.Dependency and self-reliance in two programsfor participatory sustainable development areexamined, one in Canada and the other in NewZealand. Frameworks for dependency and self-reliance aredrawn from social psychology and philosophy toexamine problematic aspects associated with theconcepts. Analysis produced a proposal foruse of the term situatedinterdependence as a way to cast the outcomesof participatory sustainable development moreprecisely. The location of the cases (Canadaand New Zealand) centers the discussion withina context of industrialized agriculture, butalso points to issues pertinent to developingcountries.  相似文献   

Use of CD134 as a primary receptor by the feline immunodeficiency virus     

Shimojima M  Miyazawa T  Ikeda Y  McMonagle EL  Haining H  Akashi H  Takeuchi Y  Hosie MJ  Willett BJ 《Science (New York, N.Y.)》2004,303(5661):1192-1195

Feline immunodeficiency virus (FIV) induces a disease similar to acquired immunodeficiency syndrome (AIDS) in cats, yet in contrast to human immunodeficiency virus (HIV), CD4 is not the viral receptor. We identified a primary receptor for FIV as CD134 (OX40), a T cell activation antigen and costimulatory molecule. CD134 expression promotes viral binding and renders cells permissive for viral entry, productive infection, and syncytium formation. Infection is CXCR4-dependent, analogous to infection with X4 strains of HIV. Thus, despite the evolutionary divergence of the feline and human lentiviruses, both viruses use receptors that target the virus to a subset of cells that are pivotal to the acquired immune response.  相似文献