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排序方式: 共有131条查询结果,搜索用时 31 毫秒
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M Ligi E Bonatti G Bortoluzzi G Carrara P Fabretti D Penitenti D Gilod AA Peyve S Skolotnev N Turko 《Science (New York, N.Y.)》1997,276(5310):243-245
Three major lithospheric plates-Antarctic, South American, and African-meet in the South Atlantic near Bouvet Island where the Mid-Atlantic Ridge (MAR), the Southwest Indian Ridge (SWIR), and the American Antarctic Ridge converge toward a fast evolving triple junction. A major magmatic pulse has recently built a new, swollen segment of the SWIR (Spiess Ridge) that is propagating toward the MAR at a rate of 4 to 5 centimeters per year, disrupting a former ridge-ridge-ridge (RRR) triple junction. A new triple junction will be established about 70 kilometers to the north when the propagating SWIR/Spiess segment will impact with the MAR, probably within the next 1 million years. The American Antarctic Ridge will take advantage of the MAR/SWIR duel by capturing an approximately 70-kilometer stretch of MAR, whereas the Antarctic plate will increase its size. 相似文献
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Emily C.Hoskins Katherine M.Halloran Claire Stenhouse Robyn M.Moses Kathrin A.Dunlap Michael C.Satterfield Heewon Seo Gregory A.Johnson Guoyao Wu Fuller W.Bazer 《畜牧与生物技术杂志(英文版)》2021,(3):935-951
Background:Administration of exogenous progesterone (P4) to ewes during the pre-implantation period advances conceptus development and implantation. This study ... 相似文献
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Hoskins JD 《Science (New York, N.Y.)》1942,96(2504):567-571
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Hoskins LM 《Science (New York, N.Y.)》1915,41(1060):608-611
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Two varieties of avocado leaves (Persea americana var Guatemalan and var Mexican) were administered to lactating goats. The Mexican variety was without effect. The Guatemalan variety in doses exceeding 20 g fresh leaf per kg bodyweight, produced damage to the mammary gland with decreased milk production. The lesions were characterised by oedema and reddening, with clots in the large ducts. Microscopically, there was widespread degeneration and necrosis of the secretory epithelium, the necrotic cells sloughing into the lumen. There was no significant cellular inflammatory response. Concentrations of antitrypsin in the milk, indicating changes in vascular permeability, increased rapidly 15 h after a single high dose, coinciding with palpable oedema. Concentrations of NAGase, indicating cell damage, increased after 24 h. Goats given multiple doses followed a similar pattern but the initial response was delayed. The toxic principle, and its mode of action in selectively damaging mammary secretory cells, remains to be determined. 相似文献