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不可逆投资理论对传统投资决策原则的挑战 被引量:2
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作者 王海滋 《求索》 CSSCI 北大核心 2007年第1期21-23,共3页
本文通过一个不可逆性投资模型,说明了简单净现值投资决策原则是需要修正的。企业应该采取稳健的原则,只有当预期的净现值大于等待的价值时,我们才应该选择投资,并且投资最好能逐步进行,以充分利用等待的价值。
关键词 净现值投资决策原则 等待的价值 逐步调节
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Do physicochemical variables regulate the distribution of zooplankton communities in reservoirs dominated by filter-feeding carp?
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作者 胡梦红 杨丽丽 刘其根 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2014年第2期266-277,共12页
The temporal and spatial distributions of zooplankton communities in the upper, middle, and lower reaches of the Xin'anjiang Reservoir, Zhejiang, China, were investigated monthly, between 2009 and 2010. Silver carp ... The temporal and spatial distributions of zooplankton communities in the upper, middle, and lower reaches of the Xin'anjiang Reservoir, Zhejiang, China, were investigated monthly, between 2009 and 2010. Silver carp (Hypophthalmichthys moBtrix) and bighead carp (Aristichthys nobilis) dominated the pelagic fish community of this large, deep reservoir. Cladocerans were distributed evenly throughout the reservoir. Rotifers were mainly found in the upper reaches, while copepods tended to assemble in the lower reaches. The Pearson correlation analysis and stepwise multiple regression were used to identify the major physicochemical gradients influencing community variations. Zooplankton community distributions were influenced by water temperature, dissolved oxygen, phosphorus, nitrogen, and silicon. Excess nutrients, in particular silicon, stimulated rotifer growth. Based on these findings, it is possible to use rotifer density as a bioindicator of eutrophic status in deep reservoir ecosystems. 展开更多
关键词 temporal distribution spatial distribution ZOOPLANKTON filter-feeding carp physicochemical variables reservoir
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