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91.
利用单自由度体系在爆炸载荷作用下的动力响应的数值解,提出了一个近似关系式,进而得到一个新评价指标△P0.742m i0.258 .同时给出了一次型FAE的TNT比当量的计算方法,分别以超压峰值△Pm和△P0.742m i0.258 为评价指标计算了某一次型FAE的TNT比当量,并进行了比较.结果表明,单纯以超压峰值为评价指标的TNT比当量结果低估了一次型FAE的超压作用.鉴于爆炸超压场测试仪器与技术已能够容易地准确测量超压峰值与比冲量,建议以△P0.742m i0.258 为一次型FAE的TNT比当量的评价指标.  相似文献   
92.
Recent years have seen a gradual adoption of a “catchment-scale” approach to flood risk management into European policy-making which, amongst other objectives, promotes rural land use change to reduce flood risk. While some exploratory studies of land managers’ attitudes exist, research is lacking on how public policies can be mobilised locally to implement these ideas. Two local initiatives were analysed in the transboundary River Tweed basin in Scotland and England during which public authorities negotiated with land managers. A combination of documents (N = 21) and interviews (N = 63) forms the basis of the data analysed. The results showed that implementation is highly dependent on the local policy framework, the activities of implementers, and land managers’ responses to (combination of) policy instruments. Several factors were identified influencing implementation such as devolution arrangements (i.e. from national to regional/local), the level of local interest on flood risk, local attitudes to compromise and collaboration, available policy instruments, and the existence of participatory catchment organisations. With limited scope for stand-alone regulatory action or funding in the short term, synergies and measures promoting co-benefits in flood risk management should be further sought in the Water Framework Directive River Basin Management Plans, as well as in cross-compliance and the new agri-environment-climate strategies of the common agricultural policy.  相似文献   
93.
River basins provide a wide range of ecosystem services important for human well-being. Ecosystem functions and their value to humans have been thoroughly studied. However, the role of governance characteristics for the sustainable management of ecosystem services has been largely ignored up to now. To close this gap, this article introduces the latest modifications to a database building on the Management and Transition Framework (MTF) that serve to study the relationship between water governance and management systems and their performance with regard to impacts on ecosystem services. This comprehensive approach facilitates structured data collection and representation in order to analyze single case studies or compare case studies regarding the governance and management of water resources and associated ecosystem services. It allows the user to investigate whether certain water governance characteristics, such as stakeholder involvement or vertical integration of governance levels, are associated with a change in the management of ecosystem services or a measurable change in their state. A simplified case from South Africa shows how the database modifications allow addressing links between governance and management processes on the one side and ecosystem services and the way they are handled on the other side. Applying the MTF database leads to evidence-based insights into best practices as well as failed management approaches and interventions. This in turn provides knowledge that can be transferred from science to practice supporting sustainable governance of ecosystem services.  相似文献   
94.
We developed a comprehensive coupling framework with a multi-objective optimization that bridges a water balance model (WBM) and a wetland service model (WSM) to supporting wetland management. The framework was tested for management in Tram Chim National Park (with four wetland zones) where hydro-economic optimization was needed. The framework used (1) a model coupling process bridging WBM and WSM to create a modular hydro-economic model (MHEM), (2) a multi-objective optimization, and (3) an anneal scheduling for scenario optimization. The framework demonstrated its competency in identifying cause–effect/interaction flows (bridges) between WBM and WSM to design MHEM to simulate optimized scenarios; for the case study, the multi-objective optimization was met for all wetland zones. Results suggested a flexible consideration of management scales for optimization, i.e. hydrologic optimization at a zone level and net benefit optimization at a Park level. Our framework is applicable to supporting complex wetland decisions considering multiple objectives.  相似文献   
95.
Over the past 25 years fetal reduction has been utilized to reduce the risks of higher-order multiple pregnancies that have resulted from overly successful infertility therapies. The demographics of multiple pregnancy patients have evolved over the past decade, with increasing proportions coming from IVF as opposed to ovulation induction, being older and a higher proportion with donor eggs. Genetic diagnosis prior to reduction is becoming more common and is very safe in experienced hands. For all starting numbers, including twins, reduction to a lower number of fetuses reduces fetal losses, prematurity, and infant mortality and morbidity. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
96.
孔宇  甄峰  李兆中  傅行行 《自然资源学报》2019,34(10):2186-2199
智慧社会的出现与发展影响着人地关系,而智能技术作为智慧社会崛起的主要动力与发展的重要支撑,正在改变着国土空间的保护、开发与治理模式,也对国土空间规划编制方法提出了新要求。当前规划编制中,智能技术在国土空间规划中的应用虽然已经有了一定的探索,在技术层面也有很多实践,但缺少对智能技术应用于国土空间规划的整体性思考。基于“生态文明”基础与“以人为本”的核心理念,在对传统规划编制与当前智能技术应用梳理的基础上,从智能感知与收集、智能分析与处理、智能评估和智能决策四个方面,系统地构建全流程的智能技术辅助国土空间规划编制的框架,以适应当前国土空间规划提出的新要求,辅助编制更合理、科学、智慧的方案。  相似文献   
97.
Strategies to involve agribusiness in the development of sustainable agricultural systems have been limited by the lack of a comprehensive conceptual framework for identifying the most critical supportive policies, programs and regulations. In this paper, we propose an efficiency/substitution/redesign framework to categorize strategies for modifying agribusiness practices. This framework is then used to identify a diverse range of short, medium, and long-term strategies to be pursued by governments, community groups, academics and agribusiness to support the transition. Strategies discussed include corporate greening, ethical investment, changing the legal status of the corporaton, new business forms and the development of ecological economics.  相似文献   
98.
The amount of ecological restoration required to mitigate or compensate for environmental injury or habitat loss is often based on the goal of achieving ecological equivalence. However, few tools are available for estimating the extent of restoration required to achieve habitat services equivalent to those that were lost. This paper describes habitat equivalency analysis (HEA), a habitat-based “service-to-service” approach for determining the amount of restoration needed to compensate for natural resource losses, and examines issues in its application in the case of salt marsh restoration. The scientific literature indicates that although structural attributes such as vegetation may recover within a few years, there is often a significant lag in the development of ecological processes such as nutrient cycling that are necessary for a fully functioning salt marsh. Moreover, natural variation can make recovery trajectories difficult to define and predict for many habitat services. HEA is an excellent tool for scaling restoration actions because it reflects this ecological variability and complexity. At the same time, practitioners must recognize that conclusions about the amount of restoration needed to provide ecological services equivalent to those that are lost will depend critically on the ecological data and assumptions that are used in the HEA calculation.  相似文献   
99.
针对我国耕地现状和目前在耕地保护中存在的问题,本文分析了制约我国耕地保护的各种因素,从政府决策和农户决策两个层面揭示了我国耕地的保护机制,勾画出了耕地保护机制的运行框架,为政府制定有关保护耕地的政策提供了可靠的依据.  相似文献   
100.
Sustainable environmental planning and management require effective integration of ecological, socioeconomic, and institutional elements. This paper presents an integrative methodological framework for sustainable environmental planning and management. The development of this integrative framework is accomplished by combining two complementary analytical approaches—Hufschmidt's conceptual framework for watershed planning and management and the ABC resource survey method. The combined methodological framework seeks to delineate and synthesize essential ecological information utilizing an integrative resource survey method. This method generates classifications of environmental significance and constraint. Areas of environmental significance and constraint are then linked to appropriate and acceptable resource management actions, implementation tools (e.g., education, technical assistance), and institutional and organizational arrangements. The integrative methodological framework was developed for application in the Rio Fortuna watershed in Costa Rica's Arenal Conservation Area. The watershed is characterized by a variety of land and resource uses, including biologically diverse and ecologically fragile protected areas, small-parcel agriculture, cattle ranching, and tourism.  相似文献   
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