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1.
香港特别行政区新界内有23 hm^2的鱼塘和22 hm^2的耕地,在“元朗-锦田-牛潭尾主要防洪改善计划”中被改变成两条防洪渠(防洪渠60号和43号).于该防洪改善计划中的生态监察调查中发现这两条防洪渠的鸟类数量均较原先的生境大大减少.在耕地改变成防洪渠43号的过程中,鸟类密度由33.9 只/hm^2减少至2.2只/hm^2.在鱼塘改变成防洪渠60号的过程中,鸟类密度由5.2 只/hm^2 减少至0.4只/hm^2.研究亦发现一些原本在鱼塘和耕地很常见的鸟类物种因为生境被改变而消失.这些转变可能和食物,植被及生境复杂程度的减少有关.另一方面,为纾缓因这防洪改善计划中损失的耕地生境,渠务署在防洪渠43号的河岸铺上混凝土草格,促进植物繁衍,为鸟类提供生境.但研究发现以混凝土草格建造的草坡并未能提供有效的纾缓措施,取代耕地生境以减少生态影响. 相似文献
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Genetic factors influence virtually every human disorder, determining disease susceptibility or resistance and interactions with environmental factors. Our recent successes in the genetic mapping and identification of the molecular basis of mendelian traits have been remarkable. Now, attention is rapidly shifting to more-complex, and more-prevalent, genetic disorders and traits that involve multiple genes and environmental effects, such as cardiovascular disease, diabetes, rheumatoid arthritis and schizophrenia. Rather than being due to specific and relatively rare mutations, complex diseases and traits result principally from genetic variation that is relatively common in the general population. Unfortunately, despite extensive efforts by many groups, only a few genetic regions and genes involved in complex diseases have been identified. Completion of the human genome sequence will be a seminal accomplishment, but it will not provide an immediate solution to the genetics of complex traits. 相似文献
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Slow response of soil organic matter to the reduction in atmospheric nitrogen deposition in a Norway spruce forest 总被引:1,自引:0,他引:1
NICOLE DÖRR KLAUS KAISER ROBERT MIKUTTA GEORG GUGGENBERGER 《Global Change Biology》2010,16(11):2990-3003
Global nitrogen (N) deposition rates in terrestrial environments have quadrupled since preindustrial times, causing structural and functional changes of ecosystems. Different emission reduction policies were therefore devised. The aim of our study was to investigate if, and over what timescale, processes of soil organic matter (OM) transformation respond to a decline in atmospheric N deposition. A N‐saturated spruce forest (current N deposition: 34 kg ha?1 yr?1; critical N load: 14 kg ha?1 yr?1), where N deposition has been reduced to 11.5 kg ha?1 yr?1 since 1991, was studied. Besides organic C and organic and inorganic N, noncellulosic carbohydrates, amino sugars and amino acids were determined. A decline in organic N in litter indicated initial effects at plant level. However, there were no changes in biomarkers upon the reduction in N deposition. In addition, inorganic N was not affected by reduced N deposition. The results showed that OM cycling and transformation processes have not responded so far. It was concluded that no direct N deposition effects have occurred due to the large amount of stored organic N, which seems to compensate for the reduction in deposited N. Obviously, the time span of atmospheric N reduction (about 14.5 years) is too short compared with the mean turnover time of litter to cause indirect effects on the composition of organic C and N compounds. It is assumed that ecological processes, such as microbial decomposition or recycling of organic N and C, react slowly, but may start within the next decade with the incorporation of the new litter. 相似文献
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通过对2010—2015 年获批的药物代谢和药物动力学(DM/PK)国家自然科学基金项目的分析,总结我国DM/PK 研究取得的
进展,展望其重要研究方向,为DM/PK 学科发展规划的制定提供参考。 相似文献
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本文着重阐述了国家重点基础研究项目(973项目)与国家重点实验室互动的专业特性和管理特性,并通过以国家973创伤项目与创伤烧伤与复合伤国家重点实验室在人才、实验设备、科技资源共享方面的运行模式,初步总结其管理、合作、互动的有利建设经验,有望更好地提高国家资源的整体整合,并为适应新世纪学科发展,对加强群体创新和组织管理创新进行了有益的思考。 相似文献
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《Revista iberoamericana de micología》2016,33(3):145-151
Invasive candidiasis in non-neutropenic critically ill patients remains a challenge for clinicians due to its association with high morbidity and mortality rates, increased incidence, and health-care costs. It is well known that early diagnosis and treatment are associated with a better prognosis. For these reasons a thorough update has been performed in this setting focused on recent Spanish epidemiology, new predictive scores and microbiological tests such as mannan antigen, mannan antibodies, Candida albicans germ-tube antibodies or (1→3)-β-D-glucan detection, molecular techniques for the detection of fungal-specific DNA, advances in antifungal treatment and educational programs in Spain. An early diagnostic and therapeutic algorithm is proposed based on the combination of scores and microbiological test. The aim of this review is to provide physicians with the best information available in order to improve the prognosis of these patients. 相似文献
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