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991.
This study documents the effects of power utility right-of-way construction and maintenance on the vegetation of a wooded wetland in North Reading, Massachusetts, USA. Neither activity had a substantial, long-term negative impact. Except for differences in size and maturity, the vegetation recovered in two years from nearly total destruction caused by construction. Maintenance that included the periodic removal of high-growing species led to the formation of a plant association different from the one occurring naturally, but as diverse and species rich. 相似文献
992.
Olen Paul Matthews 《Environmental management》1988,12(4):413-427
The Supreme Court's interpretation of the commerce clause controls the balance of power between state and federal governments in the United States. An understanding of the relationship between the different government levels is essential for resource managers concerned with resource and environmental issues. This study examines selected Supreme Court decisions between 1976 and 1988 to answer three questions raised by the commerce clause: (1) Is the regulated item an article of commerce? (2) Do state laws burden interstate commerce? (3) Is federal commerce regulation limited? The balance of power among the justices and the commerce clause theories affecting the federal role in resource management are also examined. Since ratification of the Constitution, the Supreme Court has continuously increased federal power, but states have power to act independently as long as contradictory federal laws do not exist and state law does not impermissively affect commerce. If Congress regulates an individual's use of resources, their power is unquestioned. Future Court decisions will not significantly reduce the federal role in resource management even if the Court's membership changes. Even the supporters of states' rights on the Court realize increased federal power is a necessary part of the country's evolution. The purpose of the commerce clause is to create a national economic unit with free location principles. The Court supports this purpose today and will in the future. 相似文献
993.
In the last ten years official location policy in Nigeria for urban roadside traders, an enterprising group of urban poor operating at the lowest level of the informal sector of the economy has been very negative. Government believes that they should be removed from the streets and tucked away in obscure locations because of their tendency to deface the streets with litter and for causing vehicular and pedestrian traffic congestion. This paper identifies and assesses the magnitude of pollution created by the traders as a prelude to evolving a planning policy and strategy for regulating and formally accommodating street traders in good locations while still ensuring good environmental quality. 相似文献
994.
Alberico Zeppetella 《Journal of Environmental Planning and Management》1988,31(2):103-109
The paper attempts to conceptualise a range of problems arising from project appraisals. The author presents some general considerations concerning the role of social appraisal in territorial planning, the theoretical weaknesses of cost‐benefit analysis in assessing the effects of projects on territorial resources and some questions relating to assessment methodologies and the welfare foundations of social appraisal within planning practices. The author moves away from evaluation as a technical process towards one which also incorporates ‘practical’ knowledge in a process of argumentation. 相似文献
995.
Peter F. M. McLoughlin 《Journal of the American Water Resources Association》1988,24(3):599-607
ABSTRACT: Third World irrigation and drainage systems have experienced major declines recently in both capability and performance. This is due initially to working them well beyond their design capaci-capacities; scouring, sedimentation, and overtopping result. Chronic O&M underfunding then adds heavily to this worsening malaise. International donors have assisted irrigation departments with rehabilitation projects and programs to improve O&M effectiveness on a grand (billions of dollars) scale. Despite their historical propensity to examine, almost fastidiously, program economic justifications (B/C, IRR, etc), the donors apparently have glossed over two basic analytic elements for (a) more spending on O&M as distinct from an equivalent spending on other means to provide farmers with an m3 of water; and (b) different levels of O&M spending on canals and drains. Surely those different levels provide differing benefits, in total, and at the margin. Which level is most economic? This paper identifies these latter analytical issues, posits methodologies key to an O&M spending level analysis, and discusses the information base. Particular attention is paid to identifying relevant costs and benefits, and to suggesting supplementary criteria for O&M spending level selection. The paper is an exercise in delineation of an imminently practical area of irrigation engineering economics. 相似文献
996.
M. Shiraki T. Shimada M. Tatsumichi T. Saito 《Journal of Polymers and the Environment》1995,3(1):13-21
Five extracellular PHB depolymerases of bacteria isolated from various sources were purified to electrophoretic homogeneity and compared with known extracellular PHB depolymerase fromAlcaligenes faecalis T1. The molecular mass of these enzymes were all around 40–50 kDa. Nonionic detergent, diisopropylfluorophosphate and dithiothreitol inhibited the PHB depolymerase activity of all these enzymes. Trypsin abolished PHB depolymerase activity, but not theD-3-hydroxybutyric acid dimer hydrolase activity of all the enzymes. These results showed that the basic properties of these PHB depolymerases resemble those of theA. faecalis T1 enzyme. Analysis ofN-terminal amino acid sequence of the purified enzymes revealed that these enzymes includingA. faecalis T1 enzyme fall into three groups. 相似文献
997.
998.
五氯酚对环境污染及居民健康影响研究 总被引:2,自引:0,他引:2
中国长期以来使用五氯酚纳盐杀灭亡血吸虫的中间宿主──—钉螺.为评价它对环境的污染及居民健康危害,1990-1993年在我省开展了五氯酚环境污染及对居民健康影响研究.在研究区采集环境样品(空气、水体、土壤及底泥、蔬菜、肉、蛋、鱼等)共173份;生物材料(人血、尿)共457份,分析五氯酚浓度.结果在明,在五氯酚使用区,环境中PCP浓度稍高于对照区,而生物材料尿、血中PCP浓度明显高于对照区.全血胆碱脂酶活性用药区明显低于对照区,统计学分析有显著差异(P<0.001),证实了长期低剂量使用可造成环境及生物蓄积. 相似文献
999.
1000.
Large-scale constructed wetlands for nutrient removal from stormwater runoff: An everglades restoration project 总被引:14,自引:0,他引:14
Mariano Guardo Larry Fink Thomas D. Fontaine Susan Newman Michael Chimney Ronald Bearzotti Gary Goforth 《Environmental management》1995,19(6):879-889
The South Florida Water Management District (SFWMD) constructed a wetland south of Lake Okeechobee to begin the process of
removing nutrients (especially phosphorus) from agricultural stormwater runoff entering the Everglades. The project, called
the Everglades Nutrient Removal (ENR) project, is a prototype for larger, similarly constructed wetlands that the SFWMD will
build as part of the Everglades restoration program. This innovative project is believed to be one of the largest agricultural
stormwater cleanup projects in the United States, if not in the world. This publication describes the ENR project's design,
construction, and proposed operation, as well as the proposed research program to be implemented over the next few years. 相似文献