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851.
852.
构建新农村防震减灾规划体系的初步探讨   总被引:1,自引:0,他引:1  
本文从地震灾害的破坏概况入手,结合当前新农村防震减灾规划存在的问题,揭示了新农村防震减灾规划体系要点,以供读者把握我国新农村规划建设的整体印象,在新农村规划中具有一定的理论价值和实际指导意义。  相似文献   
853.
854.
The difference between fishermen's fishing catch and the optimal fishing catch is the basic reason for the transaction of marine fishing rights (TMFR). The effects of productive cost, non-productive cost, use-cost, transaction cost, productive revenue and non-productive revenue on the TMFR and the optimal fishing catch are analyzed. This paper draws following conclu- sions: the non-productive revenue has a positive effect on the TMFR, and other factors, such as non-productive cost, usecost and transaction cost, have a negative effect; the TMFR will promote the resource allocation; the high transaction cost may affect the implementation of TMFR.  相似文献   
855.
利用2003年-2013年中国30个省份的面板数据,检验了农业现代化、信息化与农业面源污染之间的关系.研究发现,农业现代化对农业面源污染有着一定的加重作用;信息化能够有效缓解因农业现代化所导致的农业面源污染,这一现象在粮食主产省同样存在,说明信息化能够发挥减污增绿的作用;农业环境库兹涅茨曲线(EKC)也得到验证.因此,应进一步推进信息化发展,有效利用信息化对农业现代化所致农业面源污染的缓解作用,还应多措并举促进农民增收,加快农民收入越过EKC曲线拐点.  相似文献   
856.
ABSTRACT: A study of 222Rn concentrations in the water distribution system of Tucson, Arizona, revealed levels of 60 to 1260 pCi/L in domestic waters. These measurements are comparable to levels of between 80 and 1400 pCi/l for 222Rn found in ground water samples in the North-Central Tucson basin (Kahn et al., 1994). Estimated loss of 222Rn due to radioactive decay during travel from the well head to the home ranges from 8 to 50 percent.  相似文献   
857.
ABSTRACT: At a time in history when water resource development in the United States is being condemned as both economically inefficient and an environmental disaster, perhaps economists need to look back at previous development to see what the fruits of water development (be they sweet or sour) have been. The Boise Project of south-western Idaho is 70 years old and to some people it represents a gross error in resource use, while to others it represents a means of livelihood and well being. A recent research project at the University of Idaho attempted to measure not only the direct economic income benefits of the project (from irrigation), but also the indirect or secondary income benefits (from the food processing industry). Periodic regional input-output tables were constructed to assess the income generated from irrigation and food processing over the period from 1946 to 1970. Input-output analysis allowed researchers to evaluate the direct and indirect impacts of both the irrigation sector and the food processing sector and to compare their growth over time.  相似文献   
858.
Effects of different forest management policies on long-term vegetation development are incorporated into a computer simulation of a western Washington watershed. The response of a Rocky Mountain elk(Cervus canadensis nelsoni) population to these vegetation changes is simulated using information on their differential use of vegetation types. Simulations include: 1) a cessation of timber harvesting leading to an immediate decline in elk members resulting from a reduction in summer habitats; 2) a stable elk population, similar to the present one, resulting from a constant timber harvesting rate, and 3) initial increases in herd size, followed within 50 years by a sharp decrease, resulting from cutting all old growth timber within the next decade and then a cessation of timber harvestings.  相似文献   
859.
Quantifying the human health benefits of curbing air pollution in Shanghai   总被引:1,自引:0,他引:1  
Urban development in the mega-cities of Asia has caused detrimental effects on the human health of its inhabitants through air pollution. However, averting these health damages by investing in clean energy and industrial technologies and measures can be expensive. Many cities do not have the capital to make such investments or may prefer to invest that capital elsewhere. In this article, we examine the city of Shanghai, China, and perform an illustrative cost/benefit analysis of air pollution control. Between 1995 and 2020 we expect that Shanghai will continue to grow rapidly. Increased demands for energy will cause increased use of fossil fuels and increased emissions of air pollutants. In this work, we examine emissions of particles smaller than 10 microm in diameter (PM10), which have been associated with inhalation health effects. We hypothesize the establishment of a new technology strategy for coal-fired power generation after 2010 and a new industrial coal-use policy. The health benefits of pollution reduction are compared with the investment costs for the new strategies. The study shows that the benefit-to-cost ratio is in the range of 1-5 for the power-sector initiative and 2-15 for the industrial-sector initiative. Thus, there appear to be considerable net benefits for these strategies, which could be very large depending on the valuation of health effects in China today and in the future. This study therefore provides economic grounds for supporting investments in air pollution control in developing cities like Shanghai.  相似文献   
860.
水环境中重金属污染研究概述   总被引:32,自引:2,他引:32  
李然  李嘉 《四川环境》1997,16(1):18-22
重金属污染是水环境污染的一个重要方面,而水质模型是重金属污染研究的重点方法之一,作者在对溪落渡水库重金属污染的研究工作过程中,收集和整理了大量有关资料,本文概述了目前常用的重金属迁移转化动力学数学模型及建立该模型时所涉及到的重金属存在形态、污染特征,迁移转化过程等方面的研究成果和存在问题。  相似文献   
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