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排序方式: 共有521条查询结果,搜索用时 46 毫秒
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ABSTRACT: Rainwater harvesting is receiving increased attention worldwide as an alternative source of drinking water. Although collected rainwater is typically consumed without any type of disinfection, the microbial quality of this type of water source can be poor. Around the world, consumers of collected and stored rainwater may be at considerable risk to a variety of infectious diseases. This review presents studies attributing specific risks of diseases to the consumption of contaminated rainwater. Diseases attributed to the consumption of untreated rainwater include bacterial diarrheas due to Salmonella and Campylobacter, bacterial pneumonia due to Legionella, botulism due to Clostridium, tissue helminths, and protozoal diarrheas from Giardia and Cryptosporidium. Simple indicator systems such as fecal coliform measurements may prove to be inadequate for determining microbial risks associated with consumption of water from rainwater catchment systems.  相似文献   
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Recently, a number of studies have found adaptive brood sex ratio (BSR) manipulation in birds. The reason for such manipulations is thought to be the different reproductive value of male and female nestlings. Several studies have found that parental quality and food supply can affect BSR, however results are sometimes inconsistent between species and populations. We investigated BSR patterns in a Hungarian population of Collared Flycatchers (Ficedula albicollis) and compared the results with those obtained in a previous study of the same species in Sweden. We found two significant differences. First, the male forehead patch size, a heritable, sexually selected trait, affected the brood sex ratio in the Swedish population, but not in our Hungarian study population. This difference might be a consequence of the different information content of the forehead patch size in the two populations. Second, a seasonal shift in BSR (more sons late in the season) was observed in the Hungarian, but not in the Swedish population.Communicated by J. Graves  相似文献   
486.
Property Rights Case Law and the Challenge to the Endangered Species Act   总被引:1,自引:0,他引:1  
Congress is poised to initiate what could be a lengthy debate over the U.S. Endangered Species Act. In anticipation, proponents of strong Fifth Amendment private property rights guarantees have begun an aggressive campaign pitting those rights against those granted other species in the Act. Little case law exists that considers both property rights and wildlife protection, but inference can be drawn from Supreme Court opinions regarding property rights which may provide insight into likely judicial contributions to resolving tension between property rights and endangered species. We review key legislative history, provisions of the Endangered Species Act, relevant case law, and the implications of recent judicial trends that pertain to property and imperiled species. We then make recommendations that may improve implementation of this critical piece of environmental legislation.  相似文献   
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A new environmental paradigm has emerged, reflecting a change in the public's understanding of resource sustainability. Forest policy makers need to be better informed about such changes to achieve economic, social, and environmental objectives in a manner that balances human needs and aspirations with ecosystem constraints. As an aid to this task, a forest resource accounting system based on the key concept of natural capital could help reshape forest policies to provide an even wider spectrum of benefits for both present and future generations by maintaining and enhancing the productive capacity of forest capital. Such a resource accounting system would provide a tool for integrating multidimensional information requirements in measuring the health of both forest ecosystems and economic systems. This paper outlines some of the features of this accounting system and proposes and framework that would integrate economic and ecological characteristics of natural resources. Forest resource accounting is urgently needed to achieve the sustainability goals of ecosystem management.  相似文献   
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Baxter Healthcare's Cardio Vascular Group (CVG) has formed a partnership with Advanced Environmental Technical Services (AETS, formerly called AETC), an 18-year-old environmental services company based in Flanders, New Jersey. With annual revenues of nearly $100 million, AETS is the largest privately owned environmental service company of its kind. Creating a partnership with providers of hazardous waste services has become necessary for many companies that find themselves downsizing and focusing their limited resources on their core businesses. More than merely waste haulers, hazardous waste management companies are being called on to train employees, develop environmental budgets, and even serve as on-site waste managers. AETS and Baxter Healthcare's CVG have created such a partnership and have successfully reduced Baxter's hazardous waste production by 56 percent since 1992. The lessons learned from this partnership are reported in this article.  相似文献   
489.
ABSTRACT: The elimination of groundwater overdraft was a key feature of the 1980 Arizona Groundwater Management Act. To achieve this goal, the Arizona Department of Water Resources identified several Active Management Areas and developed urban, industrial, and agricultural water conservation plans. This study examines the reductions in groundwater use through agricultural water conservation in the Phoenix Active Management Area (AMA). Linear programming models are developed to analyze changes in groundwater use and net returns to agriculture over a 38-year period, 1990 to 2025, for farming areas in the Phoenix AMA. Results indicate that the agricultural conservation program provides only modest groundwater savings under a wide range of scenarios. The low level of savings is partly due to the current economically efficient use of water. Other policy measures such as retiring agricultural land may be necessary if the Phoenix AMA is to meet its overdraft reduction goals; even if urban water conservation goals are met.  相似文献   
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