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排序方式: 共有199条查询结果,搜索用时 409 毫秒
41.
中国西南地区地壳运动的GPS监测 总被引:31,自引:0,他引:31
通过1991 ̄1997年期间对中国西南地区GPS(全球定位系统)载波相位测量,建立了青藏高原东部及相邻地区现代地壳运动的速度场,相对于成都,川滇地块及其以西的速度大多为5 ̄10mm/a,鲜水河-小江断裂以东的川青地块和扬子地块运动微弱,约为0 ̄7mm/a,2个地区都表现为顺时钟的涡旋运动,而没有明显的地壳物质向东挤出或逃逸,地壳变形主要型式为顺时针旋卷构造和块体边界断裂的非均一滑动。 相似文献
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Cloning of the T gene required in mesoderm formation in the mouse 总被引:46,自引:0,他引:46
The murine developmental mutation T identifies an essential gene in mesoderm formation. Embryos lacking normal gene activity fail to form the notochord, the entire posterior region and the allantois, and die at about 10 days of gestation. We have isolated the T gene using a combination of molecular and genetic techniques, thus making molecular tools available to study processes underlying mesoderm formation in the mouse. 相似文献
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Lung cancer is the most common cancer in men in the United Kingdom and the second most common in women, accounting for between 25 and 40% of all cancer deaths. Cigarette smoking is widely accepted as the major cause of lung cancer and linear relationships have been established between the number of cigarettes smoked and lung cancer risk. Although approximately 50 carcinogenic chemicals have been identified in cigarette smoke, a causal link between specific compounds and lung cancer has yet to be made. Studies on cigarette smokers' urine, blood and placenta have provided indications of carcinogen exposure, and although the presence of covalently-bound adducts in human DNA provides evidence of exposure to carcinogens, there have been no reports of systematic studies on the levels of DNA adducts in human lung. We report here, using the 32P-post-labelling technique, that cigarette smokers have higher adduct levels than non-smokers, that there is a linear relationship between adduct levels and daily or lifetime cigarette consumption, and that people who have given up smoking for at least five years have adduct levels similar to those of non-smokers. 相似文献
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This article outlines the methodology and results of the Department of the Environment, Transport and the Regions (DETR) 1996-based household projections for England, and its regions. It examines differences between this round of projections and the previous 1992-based round. The 1996-based projections indicate that between 1996 and 2021 a growth of 3.8 million households can be expected in England, if recent trends continue. Both the national and subnational methodology and results are covered. 相似文献
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Ruiz-Perez VL Ide SE Strom TM Lorenz B Wilson D Woods K King L Francomano C Freisinger P Spranger S Marino B Dallapiccola B Wright M Meitinger T Polymeropoulos MH Goodship J 《Nature genetics》2000,24(3):283-286
Ellis-van Creveld syndrome (EvC, MIM 225500) is an autosomal recessive skeletal dysplasia characterized by short limbs, short ribs, postaxial polydactyly and dysplastic nails and teeth. Congenital cardiac defects, most commonly a defect of primary atrial septation producing a common atrium, occur in 60% of affected individuals. The disease was mapped to chromosome 4p16 in nine Amish subpedigrees and single pedigrees from Mexico, Ecuador and Brazil. Weyers acrodental dysostosis (MIM 193530), an autosomal dominant disorder with a similar but milder phenotype, has been mapped in a single pedigree to an area including the EvC critical region. We have identified a new gene (EVC), encoding a 992-amino-acid protein, that is mutated in individuals with EvC. We identified a splice-donor change in an Amish pedigree and six truncating mutations and a single amino acid deletion in seven pedigrees. The heterozygous carriers of these mutations did not manifest features of EvC. We found two heterozygous missense mutations associated with a phenotype, one in a man with Weyers acrodental dysostosis and another in a father and his daughter, who both have the heart defect characteristic of EvC and polydactyly, but not short stature. We suggest that EvC and Weyers acrodental dysostosis are allelic conditions. 相似文献
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