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81.
The effect of long-term exposure to high frequency electromagnetic field (HF EMF) on some somatic and neural characteristics was studied in neurodefective Lurcher mutant (+/Lc) and normal wild type mice (+/+). Both newborn and young adult (3 months) animals derived from two strains (C3H, B6CBA) were exposed to HF EMF (870 MHz) from 1st to 21st day or from 91st to 120th day respectively. In animals of both groups and controls we observed the development of body weight. Moreover, in the HF EMF exposed adult B6CBA animals we studied spatial learning ability, motor functions and the CNS excitability. To investigate specific energy absorption rate (SAR) in experimental animals we have done the basic 3D calculations of the electromagnetic energy distribution in the simplified model of the mouse. The HF EMF exposed animals exhibited mild differences of body weight between them and unexposed controls. The long-term exposure to HF EMF did not significantly influence the ability to learn in the Morris water maze. However, significant lower swimming speed was found in the irradiated +/Lc as well as lower motor activity of +/+ in the open field when compared to controls. No significant differences were found between HF EMF irradiated animals and controls in examination of the CNS excitability and motor functions.  相似文献   
82.
清洁生产原则的积极推广,有赖于政府、工业界和“推动组织“(例如金融和教育机构、非政府组织、技术指导人员和咨询人员、工业协会)间有效合作伙伴关系的推动与发展.本文引证了推动组织参与的一些成功行动.迫切希望不同的利益相关者在推动社会向可持续性发展转化中,发挥更积极的作用.  相似文献   
83.
要获得有意义的温室气体清单,重要的是清单中包括的内容的方法论和定义应该是一致的.国际石油工业环境保护协会(IPIECA)、国际石油和天然气生产者协会(OGP)以及美国石油学会(API)已经制定了温室气体排放计算和报告的准则.国际石油工业环境保护协会(IPITCA)报告温室气体排放的石油工业指南的重点是放在石油工业温室气体排放的计算和报告上.为了提供排放估算一致的方法论,美国石油工业协会制定了石油和天然气工业温室气体排放估算方法论概要.从美国石油学会可以得到一个估算排放的工具--SANGEATM能源和排放估算系统.  相似文献   
84.
Despite its successes, the U.S. Endangered Species Act (ESA) has proven challenging to implement due to funding limitations, workload backlog, and other problems. As threats to species survival intensify and as more species come under threat, the need for the ESA and similar conservation laws and policies in other countries to function efficiently has grown. Attempts by the U.S. Fish and Wildlife Service (USFWS) to streamline ESA decisions include multispecies recovery plans and habitat conservation plans. We address species status assessment (SSA), a USFWS process to inform ESA decisions from listing to recovery, within the context of multispecies and ecosystem planning. Although existing SSAs have a single-species focus, ecosystem-based research can efficiently inform multiple SSAs within a region and provide a foundation for transition to multispecies SSAs in the future. We considered at-risk grassland species and ecosystems within the southeastern United States, where a disproportionate number of rare and endemic species are associated with grasslands. To initiate our ecosystem-based approach, we used a combined literature-based and structured World Café workshop format to identify science needs for SSAs. Discussions concentrated on 5 categories of threats to grassland species and ecosystems, consistent with recommendations to make shared threats a focus of planning under the ESA: (1) habitat loss, fragmentation, and disruption of functional connectivity; (2) climate change; (3) altered disturbance regimes; (4) invasive species; and (5) localized impacts. For each threat, workshop participants identified science and information needs, including database availability, research priorities, and modeling and mapping needs. Grouping species by habitat and shared threats can make the SSA process and other planning processes for conservation of at-risk species worldwide more efficient and useful. We found a combination of literature review and structured discussion effective for identifying the scientific information and analysis needed to support the development of multiple SSAs. Article impact statement: Species status assessments can be improved by an ecosystem-based approach that groups imperiled species by shared habitats and threats.  相似文献   
85.
The establishment and interrelationships of microorganisms with soil and plant processes during reclamation are greatly influenced by the composition of the planting medium and vegetation practices. While in some instances the parent material may be used as the vegetation medium, the practice of topsoiling, particularly the direct haul method, may be beneficial in introducing microorganisms and improving the quality of the plant growth medium of spoils that are chemically or physically less desirable than the native soils. The influence of different vegetation types on soil development on surface mines may be a reflection of physioiogical differences that affect microbial development in the rhizosphere. Such differences include levels of carbohydrate translocated to the root system and/or released into the surrounding soil; the plant's effectiveness as a mycorrhizal host; and the rate of degradation of plant residues. It has become apparent that microbial interactions are an important part of plant and soil processes in reclamation. While some of the microorganisms important in plant growth and soil development can be introduced readily by management practices, the majority usually are disseminated by natural means and only gradually become a part of the microbial population. More research is needed on developing new methods or refining current procedures for early introduction of these microorganisms in reclamation practices.  相似文献   
86.
The present study investigated the effects of a specific union socialization program on union attitudes and loyalty. Seventy-one apprentices undergoing a union-management training program were surveyed. Using linear structural relations modelling, the research found that union attitudes and training satisfaction were the most important predictors of loyalty to the union. Furthermore, attitudes to unions were related to the union socialization process and the transformational leadership characteristics of the socializing agents.  相似文献   
87.
Native freshwater faunas in North America are declining, principally due to the combined effects of habitat degradation and introduced species. Relatively little attention has been directed to the decline of freshwater invertebrates, which may be even more threatened than fishes. This paper chronicles recent changes in the distribution and abundance of the Shasta crayfish ( Pacifastacus fortis Faxon), a state and federally endangered species endemic to the midreaches of the Pit River system in northeastern California. We made snorkeling and SCUBA surveys for crayfish in 1990 and 1991 and examined various records for historic distributions. Shasta crayfish have been extirpated from much of their historic range by water impoundment and diversion, and they are further threatened by two introduced crayfish species ( Pacifastacus leniusculus Dana and Orconectes virilis Hagen). By 1990 Shasta crayfish were restricted to seven isolated populations, mostly in the headwaters of spring-fed tributaries to the Pit river. P. leniusculus had become established throughout much of the study area in about 12 years. In one site P. leniusculus probably contributed to the precipitous decline of Shasta crayfish, from 2000–3000 in 1980 to about 370 (± 135) in 1991. O. virilis , which occurred in only the most disturbed parts of the system, showed little range expansion in 30 years and had been replaced in a large stretch of the Pit River by P. leniusculus. P. leniusculus occupied sites with a broad range of habitat variables (temperature, pH, turbidity, substrate size) partly or wholly overlapping measures of sites with the other two species. The decline of the Shasta crayfish, like the extinction of its closest relative P. nigrescens in the San Francisco Bay area earlier this century, reflects the decline of its habitat and probably pressure from the aggressive exotic P. leniusculus .  相似文献   
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Residues of organochlorines, polychlorinated biphenyls (PCBs), and heavy metals (mercury, cadmium, lead, copper and zinc) were measured in unhatched eggs of Lesser Kestrels (Falco naumanni) collected in southern Spain in 1988-1991. Although contaminants were detected in all eggs, the amounts were generally below levels known to have negative effects on reproduction. This is consistent with the relatively high hatching rate (about 80%) in the studied population. The nestling mortality was severe, however, apparently due to starvation. It cannot be discounted that pesticides had an indirect effect on the kestrel's breeding success by reducing the populations of prey.  相似文献   
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