关于上海地区屋顶绿化的思考

在上海市平面绿化工作已初见成效,大型公共绿地越来越多,城市越来越美之时,构建立体绿化 成为当务之急。本文通过对上海地区屋顶绿化的现状及存在的问题的阐述,结合绿化植物的选择和维护的一 些基本理论,展示了屋顶绿化广阔的发展前景。     

绩效与不足:建国初期农村信用合作社的借贷活动的历史考察——以鄂湘赣三省为中心

农村信用合作社是建国初期农村金融体系的重要组成部分，它的产生是新中国乡村借贷关系转型和现代化的标志之一。信用社借贷有利于农户的生产生活经营，推动了农村经济的恢复与发展，但其也存在一定的缺陷。     

Urban Influence on Costs of Production in the Corn Belt

This article determines the relative technical efficiency of rural- and urban-influenced crop/livestock enterprises in the Corn Belt. Farmers in urban-influenced locations are less technically efficient than farmers in rural locations. During 1998–2000, stochastic production frontier procedures indicate that a 10% increase in urban influence leads to a close to 4% decrease in technical efficiency. The most successful urban-influenced farms have controlled costs as effectively as rural farms. They have tended to de-emphasize that nondairy livestock activities—particularly beef and hogs—do not rely extensively on off-farm income, and have relatively large, less residential/lifestyle operations compared to less successful urban-influenced farmers. However, our statistical analysis clearly bears out the refrain in popular literature that urban proximity raises the cost for, and decreases the viability of, traditional farms.     

建设项目生态经济效益分析

从建设项目对生态经济的影响，建设项目生态经济的评价以及自然资源价值对建设项目评价的影响，论证了建设项目与生态经济对立统一的关系，提出了建设项目环境保护的重要性，建设性的提出了如何进行建设项目中的生态经济效益分析和评价，具有一定的现实意义。     

公有制内按生产要素分配实现形式探析

一般理论认为,按生产要素分配主要体现在非公有制领域和公有制领域内劳动者收入来源的多样性上.但事实上,随着我国劳动力市场的发展和完善,按生产要素分配在公有制领域内将有更大的作用空间.其具体实现形式之一,即为公有制范围内劳动收入由V+Vm构成,而且对企业利润(M)中分配后的剩余部分,仍可实行按生产要素分配,而后者是建立国有资产保值增值机制的一种新思路.     

浅析高等教育学分制与学生创新能力的培养

文章提出了培养创新人才的重要性与紧迫性；分析了高等教育学分制在激发学生学习的积极性、自主性和创新意识，培养学生的创新精神和创新能力的主要优势；探讨了高等教育学分制培养学生创新能力的主要措施。     

Symmetry and order in the portfolio allocation problem

Summary. This research studies the role of multivariate distribution structures on random asset returns in determining the optimal allocation vector for an expected utility maximizer. All our conclusions pertain for the set of risk averters. By carefully disturbing symmetry in the distribution of the, possibly covarying, returns, we ascertain the ordinal structure of the optimized allocation vector. Rank order of allocations is also established when a permutation symmetric random vector is mapped into the returns vector through location and scale shifts. It is shown that increased dispersion in the vectors of location and scale parameters benefit, ex-ante, investors as does a decrease in the rank correlation coefficient between the location and scale parameter vectors. Revealed preference comparative static results are identified for the location and scale vectors of asset returns. For most issues addressed, we arrive at much stronger inferences when a safe asset is available. Received: August 8, 2000; revised version: January 8, 2001     

Rural Population Growth, 1950–1990: The Roles of Human Capital, Industry Structure, and Government Policy

Human capital raises rural incomes, but this effect is swamped by higher returns to human capital in urban markets. This leads to "brain drain" from rural areas. Populations grow more rapidly in rural counties that have a diversified employment base. Farm population grows faster (or declines more slowly) in counties with relatively high farm income, and nonfarm populations grow faster in counties with relatively high nonfarm income. However, higher farm incomes lead to slower nonfarm population growth and vice versa. Rural county government services financed by local taxes or debt have neutral or negative effects on population growth.