永定新河治理工程几个关键问题的研究

永定新河是天津市防洪的北部防线。由于受海相来沙淤积 ,河道行洪能力大幅度下降。针对永定新河治理工程设计中涉及到的河道淤积治理方案、闸位比选、防潮闸结构型式及施工方法、闸下减淤清淤措施等诸多问题进行了分析和研究 ,提出了相应的措施和建议     

对陕西省农村社会养老保险供求主体的分析与政府作用研究

陕西是西部的农业大省,农村社会养老保险制度发展缓慢,农村养老保险市场需要寻找供需双方的均衡点,政府作为制度的提供者和政策的制定者,必须在农村社会养老保险制度建立和运营中明确思路,发挥主导作用,以保证陕西省农村养老保险健康、有序地发展。     

Modelling the effects of dam removal on migratory walleye (Sander vitreus) early life‐history stages

Many dams in the USA have outlived their intended purpose and an increasing number are being considered for removal. Yet, quantitative studies of the potential physical, biological and ecological responses are needed to assess dam removal decisions. In this paper, the responses of migratory walleye (Sander vitreus) to increased spawning habitat availability as a result of dam removal was studied by comparing scenarios with and without a high‐head dam in the Sandusky River (Ohio), a major tributary to Lake Erie. A conceptual, ecological model was proposed to define the relationship between hydrodynamics and walleye spawning, egg hatching, larval drift and survival. A mathematical, ecological model of the early life‐history stages was then developed and coupled with time series of depth and velocity predictions over the spawning grounds from a 1‐D hydrodynamic model. Model simulations were run for 1984–1993 for both the with‐ and without‐dam scenarios to assess the potential benefit of dam removal. The simulation results demonstrated that velocity, depth and water temperature are major factors influencing adult walleye spawning success. Without the dam, 10 times the amount of spawning habitat would be available for walleye to spawn. This increase in spawning habitat area resulted in up to five times the total egg deposition and seven times the larval output to the nursing grounds, based on the assumption that 5% of the walleye population of Lake Erie migrated up the Sandusky River to spawn. We concluded that the spawning habitat in the current condition (with the dam) is limiting and additional spawning habitat upstream could significantly increase the number of larval walleye drifting to Lake Erie. The model sensitivity analysis showed that the number of walleye migrating up the river in spring is the dominant factor for larval recruitment to the lake. Copyright © 2006 John Wiley & Sons, Ltd.     

无锡市城乡统筹发展初探

城乡统筹发展是解决三农问题的关键,就目前对其内涵的理解存在不同的见解。文章主要在界定城乡统筹发展内涵的基础上,介绍了无锡统筹发展的成果及今后发展的措施。     

欠发达地区新农村建设与农村公共产品供给

农村公共产品的供给对欠发达地区新农村建设意义重大，而现阶段欠发达地区农村公共产品供给却存在着供给观念滞后、供给主体单一、城乡之间供给的不公平性以及监督管理体制的缺失等突出问题。如何解决这些问题。主要应从转变观念、引入市场机制和社会力量、建立城乡一体化的公共产品供给体系、创新农村行政管理制度等方面入手。以此推动欠发达地区新农村建设的进程。     

"十五"农村水电发展分析与"十一五"发展预测

本文分析了"十五"期间农村水电发展情况,对"十一五"农村水电发展政策环境及增长情况进行了预测。     

一项关于农村五保供养制度的实证研究——以闽北地区为例

农村五保供养制度是一项具有中国特色保障鳏寡孤独残疾人基本生活权益的制度,也是我国农村社会保障体系的重要组成部分。在实地调查的基础上,分析了闽北地区农村五保供养的现实状况,提出了未来建设农村五保供养制度的若干思路。     

充分关注水质科学保障饮水安全

从我国饮水安全的现状入手，分析城乡饮水安全存在的问题，强调保障饮水安全是构建和谐社会的必然要求和水利工作的切实要务。从加强监测、科学规划，加强关键技术研究及推广应用，保护水源地、修复水环境，建立合理的体制与机制四个方面提出了做好保障饮水安全工作的建议。     

Effect of sampling density on the measurement of stream condition indicators in two lowland Australian streams

There is widespread application of indicators to the assessment of environmental condition of streams. These indicators are intended for use by managers in making various comparative and absolute assessments and often have a role in resource allocation and performance assessment. Therefore, the problem of formally defining confidence in the results is important but difficult because the sampling strategies used are commonly based on a compromise between the requirements of statistical rigour and the pragmatic issues of access and resources. It is rare to see this compromise explicitly considered and consequently there is seldom quantification of the uncertainty that could affect the confidence a manager has in an indicator. In this paper, we present a method for quantitatively assessing the tradeoffs between sampling density and uncertainty in meeting various monitoring objectives. Assessments using judgement‐based representative reaches are shown to be unreliable; instead a sampling approach is recommended based on the random selection of measuring sites. A detailed dataset was collected along two streams in Victoria, Australia, and the effect of sampling density was assessed by subsampling from this dataset with precision related to the number of sites assessed per reach length and the intensity of the sampling at each site. The sampling scheme to achieve a given precision is shown to depend on the monitoring objective. In particular, three objectives were considered: (1) making a baseline assessment of current condition; (2) change detection; and (3) detection of a critical threshold in condition. Change detection is shown to be more demanding than assessing baseline condition with additional sampling effort required to achieve the same precision. Sampling to detect a critical threshold depends on nominating acceptable values of Type I and II error and the size of the effect to be detected. Copyright © 2006 John Wiley & Sons, Ltd.     

How Has Rural Tax Reform Affected Farmers and Local Governance in China？

Using nationally representative data, the present paper examines the impact of China's ongoing rural tax reform on farmers. The difficulties in further local governance restructuring are also discussed. It is argued that the issues associated with rural taxation and local governance in China result from inherent tension between an increasingly liberalized economic system and a still centralized political system. Although rural tax reform has helped to reduce farmers' tax burdens in the short term, the establishment of an effective local governance regime requires coordinated reforms to downsize local bureaucracy by providing social security for laid-off cadres, to strengthen local accountability by granting higher local formal tax autonomy, and to promote meaningful participation by expanding local democracy.