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301.
基于长江经济带1988、2001、2012年路网数据,在Arc GIS软件支持下,以长江经济带110个地级以上城市为基本研究单元,平均可达性为测度指标,对长江经济带城市及城市间可达性进行测算,探讨其格局演变特征。结果表明:(1)长江经济带区域整体可达性改善明显,但东部地区可达性水平优于西部地区的现象未得到有效改善;(2)区域内任一栅格到达最近城市所需时间逐步缩短,1 h圈空间格局由散点分布逐步向网络分布转变;(3)可达性改善状况区域差异显著,西部地区改善值远高于中部地区,平均可达性值越大其改善值越大;(4)城市间可达性水平得到显著提升,可达性水平主导频率由1988年的12~36 h逐步转向2012年的3~12 h,城市间可达性结构改变显著。 相似文献
302.
A comprehensive approach for the evaluation of the economic feasibility of landfill mining (LFM) should take into account not only the direct costs and revenues for the private investor, but also the social benefits or costs (generally called externalities), in such a way that projects generating major social benefits (and no significant private revenues) are not overlooked.With a view to contributing to the development of a common framework for the evaluation of LFM projects, this paper presents the results of a case study where the issue of the assessment of social benefits from a LFM project is addressed. In particular, the Contingent Valuation Method is applied for the monetary assessment of the community-perceived benefits from the remediation of an old uncontrolled waste deposit by means of LFM and the conversion of the area into a park.Based on the results of a survey carried out on a random sample of people living near the old landfill, the economic values of the individual willingness to pay (WTP) for LFM and the subsequent creation of a public park were calculated and the correlations with the relevant variables (distance from the landfill site, age, income, sex, education level) assessed. The results were then suitably extended and the monetary value of the welfare increase of the whole population resident in the area and potentially affected both by LFM and the creation of the park was calculated. 相似文献
303.
NJAL ROLLINSON DAVE M. KEITH AIMEE LEE S. HOUDE PAUL V. DEBES MEGHAN C. MCBRIDE JEFFREY A. HUTCHINGS 《Conservation biology》2014,28(2):529-540
Captive‐breeding programs can be implemented to preserve the genetic diversity of endangered populations such that the controlled release of captive‐bred individuals into the wild may promote recovery. A common difficulty, however, is that programs are founded with limited wild broodstock, and inbreeding can become increasingly difficult to avoid with successive generations in captivity. Program managers must choose between maintaining the genetic purity of populations, at the risk of inbreeding depression, or interbreeding populations, at the risk of outbreeding depression. We evaluate these relative risks in a captive‐breeding program for 3 endangered populations of Atlantic salmon (Salmo salar). In each of 2 years, we released juvenile F1 and F2 interpopulation hybrids, backcrosses, as well as inbred and noninbred within‐population crosstypes into 9 wild streams. Juvenile size and survival was quantified in each year. Few crosstype effects were observed, but interestingly, the relative fitness consequences of inbreeding and outbreeding varied from year to year. Temporal variation in environmental quality might have driven some of these annual differences, by exacerbating the importance of maternal effects on juvenile fitness in a year of low environmental quality and by affecting the severity of inbreeding depression differently in different years. Nonetheless, inbreeding was more consistently associated with a negative effect on fitness, whereas the consequences of outbreeding were less predictable. Considering the challenges associated with a sound risk assessment in the wild and given that the effect of inbreeding on fitness is relatively predictable, we suggest that risk can be weighted more strongly in terms of the probable outcome of outbreeding. Factors such as genetic similarities between populations and the number of generations in isolation can sometimes be used to assess outbreeding risk, in lieu of experimentation. Evaluación del Riesgo de Depresión por Endogamia y Exogamia en un Programa de Reproducción en Cautiverio 相似文献
304.
305.
Robert E. Looney 《Resources Policy》1984,10(2):109-124
The author surveys a number of factors responsible for Saudi Arabian economic growth and concludes that, contrary to popular belief, the petroleum sectors have had more than just a short-run transitory stimulating impact on the domestic economy. It appears that changes in the level of exports (and resulting government expenditures) have a number of impacts on the non-oil sector of the economy which take some time for their full effect to be felt. Government expenditures have become somewhat independent of current oil exports, so the current oil glut and falling revenues for Saudi Arabia are not likely to be translated into slower non-oil income growth. 相似文献
306.
At present, many rural enterprises in China's mountainous areas are developing rapidly, and due to poor planning and improper
management, in an uncontrolled manner. These small enterprises are making atmospheric pollution far more serious and more
difficult to control than before. Thus, as is the case with most developing countries, China is facing the challenge of managing
the increased environmental pollution that is accompanying its economic development. This paper examines the case of cement
dust pollution in the town of Wenquan in Sichuan province in order to determine how to adjust the relationship between development
of rural enterprises and atmospheric environmental pollution in mountainous areas. Using the single objective linear programming
method, and based on the principle of overall optimization, an optimal control plan for different pollution sources was worked
out and an economic assessment on reclamation of cement dust was completed. According to our analysis, after implementation
of this plan for four years, two months, the concentrations of suspended particles in Wenquan will achieve the requirement
of the national third-order ambient air quality standard; the current serious dust pollution will be completely controlled;
and the reclamation of cement dust will totally compensate for the cost of dust control and will result in 92,000 yuan of
pure profit per year. At that time, the economy and environment will be in harmony. 相似文献
307.
湖北长江经济带洪灾机制与对策探讨 总被引:2,自引:0,他引:2
谭术魁 《长江流域资源与环境》1994,3(4):353-357
根据湖北长江经济带的洪灾历史,分析了致灾原因,并提出了抗灾、减灾对策。 相似文献
308.
Integrated Coastal Zone Management as a strategy for achieving conservation and sustainable multiple use of the coastal zone
includes various types of management initiatives. Due to natural phenomena such as tides and winds and to social and economic
activities, coastal areas undergo transformation. Coastal erosion and the disappearance of beaches as a result of wrong planning
decisions and lack of effective legislation are among the most damaging effects and to reverse them requires application of
a series of engineering techniques. Beach nourishment projects as a way towards shore protection and utilization through recreational
purposes in the Spanish and Italian coasts are noteworthy in this respect.
In beach nourishment projects, the roles of various entities, both public and private, should be clearly indicated and in
the evaluation and execution stage a series of questions should be answered for the successful completion of any nourishment
project. Past projects in the Mediterranean and experiences from recent Italian projects in Anzio and Nettuno confirm this.
For example, dredging of the entrance channel of the port of Anzio enabled middle-sized ferryboats once again to enter the
port (which had not been possible before). This will in turn increase the tourism potential of the town. Nourishment of two
beaches at these sites prevented further erosion and provided more area for recreational purposes. Expected economic contribution
of beach nourishments to the regional authority was estimated for Nettuno and Anzio; the resulting theoretical payback period
was found to be 3 yr for the former and 15 yr for the latter. 相似文献
309.
从上海市的环境现状出发,论述了环境与发展的关系问题。认为环境问题是在经济发展的过程中产生的;环境问题的解决,需要通过发展经济来获得资金和技术;而良好的环境,又为经济的发展提供有利的条件。 相似文献
310.
乌石化炼油厂污泥处理技术现状 总被引:7,自引:0,他引:7
介绍了国内外有关含油污泥的处理技术、以及乌石化炼油厂的三泥处理技术进展。 相似文献