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排序方式: 共有1174条查询结果,搜索用时 203 毫秒
91.
Abelson JF Kwan KY O'Roak BJ Baek DY Stillman AA Morgan TM Mathews CA Pauls DL Rasin MR Gunel M Davis NR Ercan-Sencicek AG Guez DH Spertus JA Leckman JF Dure LS Kurlan R Singer HS Gilbert DL Farhi A Louvi A Lifton RP Sestan N State MW 《Science (New York, N.Y.)》2005,310(5746):317-320
Tourette's syndrome (TS) is a genetically influenced developmental neuropsychiatric disorder characterized by chronic vocal and motor tics. We studied Slit and Trk-like 1 (SLITRK1) as a candidate gene on chromosome 13q31.1 because of its proximity to a de novo chromosomal inversion in a child with TS. Among 174 unrelated probands, we identified a frameshift mutation and two independent occurrences of the identical variant in the binding site for microRNA hsa-miR-189. These variants were absent from 3600 control chromosomes. SLITRK1 mRNA and hsa-miR-189 showed an overlapping expression pattern in brain regions previously implicated in TS. Wild-type SLITRK1, but not the frameshift mutant, enhanced dendritic growth in primary neuronal cultures. Collectively, these findings support the association of rare SLITRK1 sequence variants with TS. 相似文献
92.
Gilbert MT Kivisild T Grønnow B Andersen PK Metspalu E Reidla M Tamm E Axelsson E Götherström A Campos PF Rasmussen M Metspalu M Higham TF Schwenninger JL Nathan R De Hoog CJ Koch A Møller LN Andreasen C Meldgaard M Villems R Bendixen C Willerslev E 《Science (New York, N.Y.)》2008,320(5884):1787-1789
The Paleo-Eskimo Saqqaq and Independence I cultures, documented from archaeological remains in Northern Canada and Greenland, represent the earliest human expansion into the New World's northern extremes. However, their origin and genetic relationship to later cultures are unknown. We sequenced a mitochondrial genome from a Paleo-Eskimo human by using 3400-to 4500-year-old frozen hair excavated from an early Greenlandic Saqqaq settlement. The sample is distinct from modern Native Americans and Neo-Eskimos, falling within haplogroup D2a1, a group previously observed among modern Aleuts and Siberian Sireniki Yuit. This result suggests that the earliest migrants into the New World's northern extremes derived from populations in the Bering Sea area and were not directly related to Native Americans or the later Neo-Eskimos that replaced them. 相似文献
93.
Argyle E Costain CH Dewdney PE Galt JA Landecker T Roger R 《Science (New York, N.Y.)》1977,197(4306):822
94.
Radar soundings of the subsurface of Mars 总被引:2,自引:0,他引:2
Picardi G Plaut JJ Biccari D Bombaci O Calabrese D Cartacci M Cicchetti A Clifford SM Edenhofer P Farrell WM Federico C Frigeri A Gurnett DA Hagfors T Heggy E Herique A Huff RL Ivanov AB Johnson WT Jordan RL Kirchner DL Kofman W Leuschen CJ Nielsen E Orosei R Pettinelli E Phillips RJ Plettemeier D Safaeinili A Seu R Stofan ER Vannaroni G Watters TR Zampolini E 《Science (New York, N.Y.)》2005,310(5756):1925-1928
The martian subsurface has been probed to kilometer depths by the Mars Advanced Radar for Subsurface and Ionospheric Sounding instrument aboard the Mars Express orbiter. Signals penetrate the polar layered deposits, probably imaging the base of the deposits. Data from the northern lowlands of Chryse Planitia have revealed a shallowly buried quasi-circular structure about 250 kilometers in diameter that is interpreted to be an impact basin. In addition, a planar reflector associated with the basin structure may indicate the presence of a low-loss deposit that is more than 1 kilometer thick. 相似文献
95.
Macklis RM 《Science (New York, N.Y.)》2002,295(5560):1647-1648
Although Marie Curie is known primarily for her discovery of radium, her true gift to science was her realization that radioactivity is an intrinsic atomic property of matter rather than the result of chemical processes. She was one of the few Nobel laureates to win the prize twice (physics and chemistry). During her career and as one of the first prominent women scientists, she became increasingly aware of the need for funding for research and of the scientific freedom that money can bring. By nature shy and reserved, Marie's fame, as both a scientist and as an exemplar of a liberated professional woman of the roaring twenties, grew to superstar proportions. 相似文献
96.
Water Availability for Winter Wheat Affected by Summer Fallow Tillage Practices in Slope Dryland 总被引:2,自引:0,他引:2
WANG Xiao-bin CAI Dian-xiong JIN Ke WU Hui-jun BAI Zhan-guo ZHANG Can-jun YAO Yu-qing LU Jun-jie WANG Yu-hong YANG Bo Roger Hartmann Donald Gabriels 《中国农业科学(英文版)》2003,2(7)
The tillage experiments for winter wheat were conducted on the slope farmland in Luoyang,Henan Province in the semihumid to arid loess plateau areas of North China. Different tillage methods inclu-ding reduced tillage (RT), no-till (NT), 2 crops/year (2C), subsoiling(SS), and conventional tillage (CT)were compared to determine the effects of tillage methods on soil water conservation, water availability, andwheat yields in a search for better farming systems in the areas. The NT and SS showed good effects on waterconservation. The soil water storage increased 12 - 33 mm with NT and 9 - 24 mm with SS at the end of sum-mer fallow periods. The soil evaporation with NT and SS decreased 7 - 8 mm and 34 - 36 mm during the fallowperiods of 1999 and 2001, respectively. Evapotranspiration (ET) with NT and SS increased about 47 mm dur-ing wheat growth periods of 2000 to 2001. Treatment RT and 2C had low water storage and high water lossesduring the fallow periods. The winter wheat yields with conservation tillage practices were improved in the 2ndyear, increased by 3, 5 and 8 % with RT, NT and SS, respectively, compared with CT. The highest wheatyields were obtained with subsoiling, and the maximum economic benefits from no-till. All conservation tillagepractices provided great benefits to saving energy and labors, reducing operation inputs, and increasing eco-nomic returns. No-till and subsoiling have shown promise in increasing water storage, reducing water loss, en-hancing water availability, and saving energy, as well as increasing wheat yield. 相似文献
97.
98.
Hoefen TM Clark RN Bandfield JL Smith MD Pearl JC Christensen PR 《Science (New York, N.Y.)》2003,302(5645):627-630
We have detected a 30,000-square-kilometer area rich in olivine in the Nili Fossae region of Mars. Nili Fossae has been interpreted as a complex of grabens and fractures related to the formation of the Isidis impact basin. We propose that post-impact faulting of this area has exposed subsurface layers rich in olivine. Linear mixture analysis of Thermal Emission Spectrometer spectra shows surface exposures of 30% olivine, where the composition of the olivine ranges from Fo30 to Fo70. 相似文献
99.
Foote M Crampton JS Beu AG Marshall BA Cooper RA Maxwell PA Matcham I 《Science (New York, N.Y.)》2007,318(5853):1131-1134
In the time between speciation and extinction, a species' ecological and biogeographic footprint-its occupancy-will vary in response to macroecological drivers and historical contingencies. Despite their importance for understanding macroecological processes, general patterns of long-term species occupancy remain largely unknown. We documented the occupancy histories of Cenozoic marine mollusks from New Zealand. For both genera and species, these show a distinct pattern of increase to relatively short-lived peak occupancy at mid-duration, followed by a decline toward extinction. Thus, species at greatest risk for extinction are those that have already been in decline for a substantial period of time. This pattern of protracted rise and fall stands in contrast to that of incumbency, insofar as species show no general tendency to stay near maximal occupancy once established. 相似文献
100.