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排序方式: 共有816条查询结果,搜索用时 31 毫秒
761.
通过社会代谢多尺度综合分析方法,评价东北、华北、西北、西南、华中、华东2003年和2007年的社会代谢状况,并结合社会代谢多尺度综合分析与因素分解等方法进行对比分析,识别出限制区域可持续发展的关键因素。结果表明,华北、东北、西北、华中和华东区迫切需要采取措施调整区域产业结构;西南区亟需加大资本技术的引进力度,以解决不同区域经济发展中的资本技术聚集与区域产业结构的不协调问题。从与2003年的对比来看,2007年社会负担出现南方转移到北方的倾向,而且除东北地区外其他地区的资源品质和数量与技术水平的改善状况与社会发展需求不相协调,致使六大区的社会代谢状况略显异常。 相似文献
762.
海拔梯度由于包含了温度、水分、光照等环境因子的剧烈变化而成为研究植物的环境适应性及其对全球气候变化响应的理想区域。在卧龙自然保护区沿海拔梯度研究了华西箭竹(Fargesia nitida(Mitford)T.P.Yi)分株的丛结构,比叶面积(SLA)、基径、株高、枝下高、单株地上部生物量及各器官生物量的分配。结果表明:华西箭竹丛结构表现为平均单丛面积和丛密度随着海拔升高呈先增大后降低的趋势,而单丛分株数先减少后增大;华西箭竹分株生长特征除SLA和枝下高线性降低,其他各调查变量随着海拔升高,总体呈先增大后减小的单峰变化趋势,高峰值在2 800 m附近。反映了环境因子随海拔升高的非线性变化。分析认为,高海拔地区的华西箭竹对温度较为敏感,气候变暖将有利于它的生长,因此其分布上限可能会提高。本研究结果拓展和丰富了海拔梯度上植物对异质性环境的适应和响应的规律研究,也可对地震后保护区植被的恢复与重建提供科学参考。 相似文献
763.
Udo E. Simonis 《The Environmentalist》2002,22(1):29-42
With the beginning of the new millennium, the longstanding need for reform of the United Nations system has gained new momentum. Efficiency gains and better coordination are desirable, though not sufficient to bring about improvement in international relations. There is need, therefore, to look for institutional innovations that would upgrade the pressing tasks of environmental and development policy in the eyes of national governments, international organizations, and non-governmental organizations, improve the institutional setting for the negotiation and implementation of new agreements and action programs, and strengthen the action capacity of the developing countries on these matters. The present article points to and elaborates on the need for a World Environment and Development Organization within the United Nations system, and outlines the shape it might be given. 相似文献
764.
Akim M. Rahman 《The Environmentalist》2002,22(4):387-392
The recent resolution of the seventh Conference of the Parties to the Climate Convention (COP7) indicates that if a country is required to comply with the pollution limit, part of the required reduction in levels of emission will have to be achieved domestically. With this status quo, policy practitioners may opt to design emission level standards along with the provision of allowing access to the international permit market that may facilitate carbon offset crediting to the country. In policy formulation cognate to electricity generation through coal combustion, it is suggested that end-users will pay emission compliance costs in terms of the price of electricity usage and the companies will offer a rebate on reduction to those who curtail the level of usage of electricity. Under the scheme proposed, the generating company(s) will face the consequences if it fails to comply to domestic emission standards. In practice, the proposed method can ensure Pareto efficiency and exhibit Pareto improvement in two-party cases where both parties have joint interest in profit maximization, but they may have dichotomy in their activities. In dealing with domestic greenhouse gas issues, the proposal becomes appealing to parties for reducing the level of emissions. Moreover, it may produce a greater degree of abatement of CO2 emissions over the levels of abatement resulting from policies of consumer or producer liability assignments. 相似文献
765.
The concept of a recycling system aiming at the recovery of resources from manufactured articles is proposed. The system integrates electronic labels for product identification and internet for global data exchange. A prototype for the recycling of electric motors has been developed, which implements a condition-based recycling decision system to automatically select the environmentally and economically appropriate recycling strategy, thereby opening a potential market for second-hand motors and creating a profitable recycling process itself. The project has been designed to evaluate the feasibility of electronic identification applied on a large number of motors and to validate the system in real field conditions. 相似文献
766.
Geographic information systems (GIS), global positioning systems and remote sensing have been increasingly used in public health settings since the 1990s, but application of these methods in humanitarian emergencies has been less documented. Recent areas of application of GIS methods in humanitarian emergencies include hazard, vulnerability, and risk assessments; rapid assessment and survey methods; disease distribution and outbreak investigations; planning and implementation of health information systems; data and programme integration; and programme monitoring and evaluation. The main use of GIS in these areas is to provide maps for decision-making and advocacy, which allow overlaying types of information that may not normally be linked. GIS is also used to improve data collection in the field (for example, for rapid health assessments or mortality surveys). Development of GIS methods requires further research. Although GIS methods may save resources and reduce error, initial investment in equipment and capacity building may be substantial. Especially in humanitarian emergencies, equipment and methodologies must be practical and appropriate for field use. Add-on software to process GIS data needs to be developed and modified. As equipment becomes more user-friendly and costs decrease, GIS will become more of a routine tool for humanitarian aid organisations in humanitarian emergencies, and new and innovative uses will evolve. 相似文献
767.
一般持续发展论(下) 总被引:8,自引:1,他引:7
杨开忠 《中国人口.资源与环境》1994,4(2):7-12
本文比较全面地论述了持续发展的由来、概念、目标和战略要素。作者指出,持续发展的提出反映了人类对自身与环境关系的认识进入新阶段;是既满足当代人和局部需要又不危害后代人和全球满足需要能力的发展,包括一般持续发展论、全球持续性、区域持续性和部门持续性。作者认为,社会福利既包括人造产品也包括自然资本,持续发展的目标在于促进社会福利的增长与公平分配,以及生态系统的持续性;而达到持续发展目标的战略要素则包括经济结构的生态现代化、实行以预防为主的环境政策、经济机制的生态现代化、实行有控制的人口转变以及反贫困。在目标和战略要素的论述中,作者提出了发达和发展中国家(地区)应分别实行强持续性和弱持续性。 相似文献
768.
Regression analysis of forest damage by marginal models for correlated ordinal responses 总被引:1,自引:1,他引:0
Studies on forest damage generally cannot be carried out by common regression models, for two main reasons: Firstly, the response variable, damage state of trees, is usually observed in ordered categories. Secondly, responses are often correlated, either serially, as in a longitudinal study, or spatially, as in the application of this paper, where neighbourhood interactions exist between damage states of spruces determined from aerial pictures. Thus so-called marginal regression models for ordinal responses, taking into account dependence among observations, are appropriate for correct inference. To this end we extend the binary models of Liang and Zeger (1986) and develop an ordinal GEEI model, based on parametrizing association by global cross-ratios. The methods are applied to data from a survey conducted in Southern Germany. Due to the survey design, responses must be assumed to be spatially correlated. The results show that the proposed ordinal marginal regression models provide appropriate tools for analysing the influence of covariates, that characterize the stand, on the damage state of spruce. 相似文献
769.
提出基于GSM的可移动危险源处警系统总体方案,在技术实施中考虑现有的可行性通讯资源和低成本实现,采用GSM网络短信息通信,利用带有移动通讯装置和PC机的主站设备来实现。利用GSMAT指令控制收发短信息,并应用数据库对短信息进行管理。对可移动危险源体系、预警方法以及相关关键技术进行较为深入的分析和研究,并在VB环境下编程实现可移动危险源处警系统的基本功能以及通信控件的查询工作方式和事件驱动方式的过程。该研究成果对可移动危险源跟踪、定位、监控,降低可移动危险源的爆炸、泄漏,避免造成重大事故具有一定的实用价值。 相似文献
770.
省际边界区域是个特殊的地理单元,对此类区域的研究大多限于经济的协同发展,集中在东部和中部地区。选取云贵两省交界的曲靖市(域)作为研究对象,在分析边界区域城市化特征的基础上,指出发挥边缘效应,突破边界障碍,优先发展中心城区,重点发展大城市,走链条状的空间发展道路是该地区特色城镇化道路的最佳选择。 相似文献