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131.
132.
Differences in Rh type between age groups of leukaemia patients 总被引:1,自引:0,他引:1
F V De George 《Nature》1970,228(5267):168-169
133.
假设文献[1]中的各个企业之间除了在库存管理方面进行合作外,还没有意识到在市场广告和供应链生产方面的合作,企业处于分别决策状态,每一个企业最大化其自身的利润。在给出考虑广告和产品结构的供应商管理库存系统的Nash非合作博弈模型,分析博弈结果和一些性质。最后给出一个算例说明本文的理论。 相似文献
134.
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136.
George B. Pendlebury 《西北部美国博物学家》2011,36(1)
A second record of the long-nosed snake in Idaho was taken at the entrance to Bruneau Dunes State Park, Owghee County 相似文献
137.
Studies of Great Basin faunas can provide information for landscape-level adaptive management by federal agencies and shed light on potential effects of climate change in continental interior landscapes. To provide such information, we characterized the butterfly fauna of the Toquima Range, a mountain range in the heart of the Great Basin with topography typical of the region. We also compared the butterfly fauna of the Toquima Range to that of the adjacent Toiyabe Range, which is more topographically complex and species rich but less representative of the Great Basin on the whole. We explicitly addressed the effects of area and water availability on butterfly species richness. Butterfly species presence data were compiled for 14 canons and 1 peak in the Toquima Range. Data from 11 canyons that we inventoried systematically were amenable to statistical analysis. Eighty butterfly species (59 residents) have been recorded from the Toquima Range since 1935. By comparison, 99 species have been recorded from the Toiyabe Range. Mean canyon-level butterfly species richness was significantly lower in the Toquima Range than in the Toiyabe Range. This difference cannot be explained by differences in canyon size between mountain ranges. Within the Toquima Range water availability seems to have a dominant effect on butterfly species richness. Between mountain ranges species richness is influenced by interactions among areas, moisture, and topography. These data should assist managers in developing guidelines for conservation planning in the Great Basin. 相似文献
138.
SuiYan Fu QuanQi Shi Chi Wang George Parks Ling Zheng Hao Zheng WeiJie Sun 《科学通报(英文版)》2011,56(12):1182-1187
A research topic of great interest to the space physics community is the observation of plasmas flowing at hundreds of kilometers
per second in the Earth’s plasma sheet. Although considerable effort has been made to understand the source of fast-flowing
plasmas, many questions remain unanswered about the mechanisms that produce high-speed flows and the effects they have on
magnetospheric disturbances, especially their contributions to magnetospheric convection and substorms. In this paper, we
discuss briefly the history of high-speed flows and review the proposed mechanisms, signatures of high-speed flows in auroras
and their interaction with the background plasma. We then summarize the relationships between high-speed flows and magnetic
structures, discuss questions associated with substorms, and finally pose several important scientific questions that need
to be addressed. 相似文献
139.
Somatic coding mutations in human induced pluripotent stem cells 总被引:2,自引:0,他引:2
140.
The largest products of magmatic activity on Earth, the great bodies of granite and their corresponding large eruptions, have a dual nature: homogeneity at the large scale and spatial and temporal heterogeneity at the small scale. This duality calls for a mechanism that selectively removes the large-scale heterogeneities associated with the incremental assembly of these magmatic systems and yet occurs rapidly despite crystal-rich, viscous conditions seemingly resistant to mixing. Here we show that a simple dynamic template can unify a wide range of apparently contradictory observations from both large plutonic bodies and volcanic systems by a mechanism of rapid remobilization (unzipping) of highly viscous crystal-rich mushes. We demonstrate that this remobilization can lead to rapid overturn and produce the observed juxtaposition of magmatic materials with very disparate ages and complex chemical zoning. What distinguishes our model is the recognition that the process has two stages. Initially, a stiff mushy magma is reheated from below, producing a reduction in crystallinity that leads to the growth of a subjacent buoyant mobile layer. When the thickening mobile layer becomes sufficiently buoyant, it penetrates the overlying viscous mushy magma. This second stage rapidly exports homogenized material from the lower mobile layer to the top of the system, and leads to partial overturn within the viscous mush itself as an additional mechanism of mixing. Model outputs illustrate that unzipping can rapidly produce large amounts of mobile magma available for eruption. The agreement between calculated and observed unzipping rates for historical eruptions at Pinatubo and at Montserrat demonstrates the general applicability of the model. This mechanism furthers our understanding of both the formation of periodically homogenized plutons (crust building) and of ignimbrites by large eruptions. 相似文献