EXTRA URBAN AND INTRA URBAN RAINFALL ENHANCEMENT BY A MEDIUM SIZED CITY1

An experiment on urban effects of warm season rainfall of a moderately sized city and its downwind towns found no evidence of global enhancement. However, there are grounds for believing that the intra urban distribution of precipitation is influenced by urban variables among which air pollution and urban roughness are considered primary. The presence of an urban heat island did not appear to improve rainfall. On the contrary, it appears to be a factor in the relative aridity of the downtown sector of the city.     

Effects of Fish Stocking on Ecosystem Services: An Overview and Case Study Using the Stockholm Archipelago

In this article, we focus on documented and possible effects of fish stocking in terms of ecosystem services. The increasing use of fish stocking between 1970 and 2000 in the semiurban setting of Stockholm archipelago, Sweden, is used as case study. The objective is to analyze this management practice from an ecosystem perspective, accounting for both the ecological and social context of releasing fish. The results show that enhancements of four native species (Salmo S. trutta, Salmo salar, Stizostedion lucioperca, and Anguilla anguilla) have dominated over new introductions of one nonnative species. (Oncorhynchus mykiss). The major objective has been to increase fish catches for local resource users. Involved stakeholders include three management agencies, one hydropower company, and several local sport fishing associations. Documented effects focus on recapture and production rates. However, our analysis suggests that additional positive or negative effects on biodiversity, food web dynamics, mobile links, or ecological information may also result, with possible consequences for the long-term provision of food, game, and aesthetic values. We conclude that a more adaptive and cooperative management approach could benefit from a deeper analysis of where, when, and what species is released, by whom, which stakeholders that use the fish and those ecosystem services the fish generate, and of the role of formal and informal institutions for monitoring and evaluating the success of releasing fish.     

旅皖国内旅游者消费结构初探

分析比较了2001年旅皖国内旅游者消费结构的特点和原因,认为国内旅游者消费结构以刚性旅游消费为主,弹性旅游消费比重较低;普遍具有较强的住宿、餐饮消费偏好,购物、娱乐是消费弱项.为引导旅游者关注弹性消费,实现消费结构合理化,促进安徽省旅游业产业结构的优化升级和经济效益的持续增长,应构建形式多样的大众娱乐设施,丰富旅游景区的娱乐功能,提升旅游商品档次和销售能力,建设多功能购物街,多方位营造安全的旅游消费环境.     

九华山国内客源市场空间结构与出游行为研究

在实地调查的基础上，分析了九华山国内客源市场空间结构及其演变特征，得出国内客源市场集中程度降低、客源吸引力不断增强、波浪式推进的演变结论，并探讨了九华山旅游行为空间模式主要以单一目的地旅游模式和区域旅游模式为主，根据旅游意向调查结果显示，九华山与黄山在客源市场方面具有较强的互补性。     

天柱山国内旅游市场空间结构分析与优化

从旅游客源和客流两方面分析了天柱山国内旅游市场的空间结构特征及其演化:2002年与1996年相比,天柱山国内旅游客源市场有扩散趋势,但仍呈较强的集中性,客源吸引半径小幅上升,呈明显的近程性;旅游客流在景区空间呈现多中心辐射扩散的分布点.在此基础上,划分了天柱山国内旅游市场空间圈层结构,对不同的圈层结构提出了不同的经营策略,以达到优化市场空间结构的目的.     

空间结构施工中人为错误与对策

空间结构展示了一个国家建筑科技新成果和实力 ,由于建筑业的特殊性 ,其安全性备受关注。笔者阐述了空间结构的施工特点以及施工中人为错误的成因和对工程的影响 ,通过对人为错误与建筑风险造价关系的分析 ,提出了控制人为错误的对策为 :适当提高结构设计可靠度水平和加强施工过程的管理 ,减少人为错误的发生 ,对遏制工程质量事故具有指导意义。     

Recovery of the Benthic Macroinvertebrate Community in a Small Stream After Long-Term Discharges of Fly Ash

Recovery of the benthic macroinvertebrate community in a small east Tennessee stream impacted by fly ash discharges from a power plant was investigated over a period of 6.5 years. The rate of recovery was greatest in the first 2 years after an initial 75% reduction in coal use led to a similar reduction in ash discharges and associated contaminants; further recovery followed after all fly ash discharges ceased. Recovery of the stream progressed through two phases. In the first phase, which lasted for approximately the first 2 years, most density and richness metrics increased considerably. In the second phase of recovery, the increases in metric values were followed by declines before fluctuating in and out of the lower reference ranges for the metrics. Detrended correspondence analyses and indicator species analyses showed that changes in species composition and community structure were ongoing throughout the second phase. Thus, the first phase was characterized by species additions, while the second phase involved species replacements and shifts in community dominants. Further recovery of the macroinvertebrate community will probably depend on additional flushing of fly ash deposits from the streambed and flood plain, because their continued presence reduces habitat quality in the stream and serves as a potential source of contaminants. Further recovery also may be limited by the availability of vagile species in nearby watersheds.     

日本弓背蚁群体结构及其开发价值

本文调查研究了日本弓背蚁的群体结构和生物学特性,并初步探讨了日本弓背蚁的营养价值及其开发利用对策.     

建筑结构减震控制新体系——减轻城市地震灾害的有效途径

本文提出一种崭新的,更加安全、有效、简单、经济,且能适用于不同地震烈度区的结构减震控制体系,包括结构隔震体系,结构消能减震体系,被动和主动减震控制体系,并介绍这种新体系的减震机理、构造方案、试验成果、减震动力理论分析,以及在国内外的最新研究发展和应用情况,包括作者在该领域所取得的最新试验研究、理论和工程应用成果,并以减轻城市地震灾害为目标,探讨了抗震结构今后的发展方向。     

The town scheme approach to urban conservation in England and Scotland

The Town Scheme approach to urban conservation is being used increasingly as a major method of repairing historic buildings in conservation areas. A Town Scheme involves a long‐term financial and administrative partnership between the various levels of government. An annual budget made up of equal contributions from central government and the participating local authority is used to finance a multi‐year programme of repairs. Owners can apply for grants which are usually for 40 per cent of approved costs, and repair work must relate to the original structure and architectural details of an approved list of historic buildings. Town Schemes by themselves cannot totally transform the environmental quality of conservation areas, and the most successful schemes are part of wide‐ranging renewal and enhancement projects.