THE PARTITION OF ENERGY     

Magie WF 《Science (New York, N.Y.)》1906,23(579):161-178

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Cell biology. Irremediable complexity?     

Gray MW  Lukes J  Archibald JM  Keeling PJ  Doolittle WF 《Science (New York, N.Y.)》2010,330(6006):920-921

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地形和土壤/土地利用空间聚合对径流和输沙量影响的AnnAGNPS模拟   总被引：4，自引：1，他引：3  

钟科元  陈兴伟  陈莹  刘梅冰 《农业工程学报》2016,32(8):127-135

为进一步揭示分布式水文模型子流域划分对径流和输沙量模拟的影响,以东南沿海桃溪流域为研究区,构建日尺度产流产沙的AnnAGNPS模型,基于9种不同临界源面积(critical source area,CSA),分析了不同子流域划分对输入参数空间聚合的影响,并设置7种组合情景,分别从年和日尺度,定量区分了地形与土壤/土地利用参数的空间聚合对产流产沙过程的影响。结果表明:1)随着CSA取值的增加,地形、土壤和土地利用类型在空间上存在明显的聚合。2)土壤/土地利用参数空间聚合导致年平均径流量和输沙量减少,且对输沙量影响更显著;地形参数的空间聚合导致年输沙量减少,但对年平均径流量无显著影响。3)地形参数的空间聚合造成的洪峰流量增加、峰现时间提前,是影响日径流过程变化的主要因素。4)土壤/土地利用参数的空间聚合对多年平均最大1 d、连续最大5 d输沙量的影响随着聚合程度的增加而显著下降,而地形参数的空间聚合造成日输沙过程峰值的出现时间提前。  相似文献   

Leigh Page: 1884-1952     

Swann WF 《Science (New York, N.Y.)》1953,117(3038):289-290

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Comment on "Determination of deforestation rates of the world's humid tropical forests"     

Fearnside PM  Laurance WF 《Science (New York, N.Y.)》2003,299(5609):1015; author reply 1015

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Current United States Department of Agriculture-Agricultural Research Service research on understanding agrochemical fate and transport to prevent and mitigate adverse environmental impacts     

Hapeman CJ  McConnell LL  Rice CP  Sadeghi AM  Schmidt WF  McCarty GW  Starr JL  Rice PJ  Angier JT  Harman-Fetcho JA 《Pest management science》2003,59(6-7):681-690

Environmentally and economically viable agriculture requires a variety of cultivation practices and pest management options as no one system will be appropriate for every situation. Agrochemicals are some of the many pest control tools used in an integrated approach to pest management. They are applied with the intent of maximizing efficacy while minimizing off-site movement; however, their judicious use demands a practical knowledge of their fate and effects in agricultural and natural ecosystems. Agrochemical distribution into environmental compartments is influenced by the physical and chemical properties of the agrochemical and environmental conditions, ie soil type and structure, and meteorological conditions. Agricultural Research Service (ARS) researchers working in the area of agrochemical fate have focused on accurately describing those processes that govern the transport, degradation and bioavailability of these chemicals under conditions reflecting actual agronomic practices. Results from ARS research concerning the environmental fate and effects of agrochemicals have led to the development of science-based management practices that will protect vulnerable areas of the ecosystem. The new challenge is to identify these vulnerable areas and the temporal and spatial variations prior to use of the chemical by predicting how it will behave in environmental matrices, and using that information, predict its transport and transformation within an air- or watershed. With the development of better predictive tools and GIS (Geographic Information System)-based modeling, the risks of agricultural management systems can be assessed at the watershed and basin levels, and management strategies can be identified that minimize negative environmental impacts.  相似文献   

The cultivation of hydra under controlled conditions     

LOOMIS WF 《Science (New York, N.Y.)》1953,117(3047):565-566

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Treatment of infectious ovine keratitis     

RILEY WF  BARNER RD 《Journal of the American Veterinary Medical Association》1953,123(920):434-435

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Cesarean section in ewes     

RILEY WF 《Journal of the American Veterinary Medical Association》1953,122(913):272-273

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Sexual differentiation in Hydra; control by carbon dioxide tension     

LOOMIS WF 《Science (New York, N.Y.)》1957,126(3277):735-739

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