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71.
Many “natural” areas are exposed to military or recreational off-road vehicles. The interactive effects of different types of vehicular disturbance on vegetation have rarely been examined, and it has been proposed that some vegetation types are less susceptible to vehicular disturbance than others. At Fort Riley, Kansas, we experimentally tested how different plant community types changed after disturbance from an M1A1 Abrams tank driven at different speeds and turning angles during different seasons. The greatest vegetation change was observed because of driving in the spring in wet soils and the interaction of turning while driving fast (vegetation change was measured with Bray-Curtis dissimilarity). We found that less vegetation change occurred in communities with high amounts of native prairie vegetation than in communities with high amounts of introduced C3 grasses, which is the first experimental evidence we are aware of that suggests plant communities dominated by introduced C3 grasses changed more because of vehicular disturbance than communities dominated by native prairie grasses. We also found that vegetation changed linearly with vehicular disturbance intensity, suggesting that at least initially there was no catastrophic shift in vegetation beyond a certain disturbance intensity threshold. Overall, the intensity of vehicular disturbance appeared to play the greatest role in vegetation change, but the plant community type also played a strong role and this should be considered in land use planning. The reasons for greater vegetation change in introduced C3 grass dominated areas deserve further study.  相似文献   
72.
Assessing groundwater resources in the arid and semiarid borderlands of the United States and Mexico represents a challenge for land and water managers, particularly in the Transboundary Santa Cruz Aquifer (TSCA). Population growth, residential construction, and industrial activities have increased groundwater demand in the TSCA, in addition to wastewater treatment and sanitation demands. These activities, coupled with climate variability, influence the hydrology of the TSCA and emphasize the need for groundwater assessment tools for decision‐making purposes. This study assesses the impacts of changes in groundwater demand, effluent discharge, and climate uncertainties within the TSCA from downstream of the Nogales International Wastewater Treatment Plant to the northern boundary of the Santa Cruz Active Management Area. We use a conceptual water budget model to analyze the long‐term impact of the different components of potential recharge and water losses within the aquifer. Modeling results project a future that ranges from severe long‐term drying to positive wetting. This research improves the understanding of the impact of natural and anthropogenic variables on water sustainability, with an accessible methodology that can be globally applied.  相似文献   
73.
综合分析了美国水环境生物监测体系的框架,对相关法律法规、生物监测技术体系的构成,包括生物种群/群落调查、毒性试验、微生物测试、鱼组织污染物分析的主要内容与开展意义进行了较为系统的描述。对我国深入开展水环境生物监测提供了一些参考借鉴,建议完善法律法规;更新方法体系,完善质量标准;逐步拓展生物监测能力。  相似文献   
74.
英国按照《职业安全和卫生法(1974)》,以职业安全卫生执行局(HSE)为执法和调查统计的主管机构,建立了以RIDDOR95规程为基础的企业雇主对其作业场所职业卫生记录和报告制度,同时HSE采取多种形式的政府主动调查,形成了较为完善的职业卫生调查统计体系。目前,我国职业卫生的调查统计体系尚未形成。以系统的方法和思路,从英国的职业卫生法规、监管入手,分析其调查统计体系,并采用对比分析的方法,将英国的体系与美国进行对比,学习工业发达国家的共同经验,为我国建立职业卫生统计体系提供借鉴。研究认为,上层法律及配套规范齐全、形成了政府主动调查与企业雇主主动记录和报告相结合的统计方式,以及调查统计数据定期向公众发布和实现信息共享是英美两国体系的共同特征。  相似文献   
75.
Gasification is the thermochemical conversion of organic feedstocks mainly into combustible syngas (CO and H2) along with other constituents. It has been widely used to convert coal into gaseous energy carriers but only has been recently looked at as a process for producing energy from biomass. This study explores the potential of gasification for energy production and treatment of municipal solid waste (MSW). It relies on adapting the theory governing the chemistry and kinetics of the gasification process to the use of MSW as a feedstock to the process. It also relies on an equilibrium kinetics and thermodynamics solver tool (Gasify®) in the process of modeling gasification of MSW. The effect of process temperature variation on gasifying MSW was explored and the results were compared to incineration as an alternative to gasification of MSW. Also, the assessment was performed comparatively for gasification of MSW in the United Arab Emirates, USA, and Thailand, presenting a spectrum of socioeconomic settings with varying MSW compositions in order to explore the effect of MSW composition variance on the products of gasification. All in all, this study provides an insight into the potential of gasification for the treatment of MSW and as a waste to energy alternative to incineration.  相似文献   
76.
The East-West Center convened the international conference on climate policy in Honolulu, Hawaii, on September 4–6, 2003. Sponsored by the Dutch Ministry of Housing, Spatial Planning and the Environment, the Japanese Ministry of the Environment, Industrial Technology Research Institute (Taiwan), and Institute for Global Environmental Strategies (Japan), this major event covered almost every important issue and featured perspectives from the most important parties and stakeholders in formulating and implementing climate policies and taking international climate negotiations further. It brought together a remarkable cross-section of world opinion on climate policy after Kyoto. This report provides a summary of each presentation and highlights discussions organized under the following six session headings: Session 1: Climate Change in Focus – From Science to Policy; Session 2: U.S. Climate Policy and Perspectives; Session 3: European Union Climate Policy and Perspectives; Session 4: Challenges for other Major Industrialized Countries; Session 5: Issues Related to Developing Countries; and Session 6: Panel Discussions: Where Do We Go from Here?.  相似文献   
77.
介绍了美国在如何通过源头消减、再循环利用、堆肥等措施提高城市固体废物回收利用率,采取城市固体废弃物填埋、废弃物能量回收等方面的众多举措以减少废物的最终处置量.并阐述了在提高城市固体废物收集效率、降低日常运营成本等方面所做出的探索努力,促使美国城市固体废物的回收利用走上了良性循环的发展道路,对中国城市固体废物的日常管理及发展方向具有一定的参考借鉴作用.  相似文献   
78.
总结分析了中美两国二噁英有关标准的特点。我国二噁英相关的标准体系有待完善,主要集中在重点行业的烟气排放标准方面。美国二噁英相关标准体系较为完善,以风险评估为重点,二噁英排放源涉及的行业划分细致。排放标准分级明显,技术导向明显。通过对比分析指出,我国应继续深化重点行业的烟气排放控制的策略。加强二噁英风险评估的基础性研究工作,以减排技术为基础,强化分级管理的思路,并针对不同排放源细化二噁英的标准。  相似文献   
79.
徐萍 《上海环境科学》2006,25(6):266-268
随着科学技术的发展,环境保护越来越受到重视,大型仪器设备在环境科学研究中的应用也越广泛。文章分析了上海市环境科学研究院原大型精密仪器的使用状况,介绍了大型精密仪器网络化管理模式、网络化管理的意义及需注意的问题,以及网络化管理后取得的成效等,以期为其他同类企事业单位提供参考。  相似文献   
80.
论文通过对使用者成本法的关键变量折现率的文献梳理,提出使用社会折现率来消除目前使用者成本法估算中对折现率选取的随意性,在对美国社会折现率估算的基础上,运用使用者成本法对美国油气资源使用者成本进行估算,发现美国从2000年以来,油气资源使用者成本上升显著,从2000年的185.08×108美元上升到2008年的2 264.28×108美元,并且发现油气资源使用者成本的涨落受社会折现率的影响较大。用美国油气资源权利金实缴数据同其使用者成本进行比较,得出美国油气资源权利金的增长速度慢于其使用者成本的增长速度,相关费金对使用者成本的补偿程度在下降,有偿使用费金对使用者成本的补偿比例从2002年高位的42.68%下降到2008年的10.83%。  相似文献   
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