明代皖南平原的圩田与农业生产

洪武时期，旧有圩田得到迅速恢复；建文至正德期间，圩田有较明显的发展，扩大了耕地面积，富豪围垦在其中占有重要地位，同时，圩田发展与蓄水防洪的矛盾已经凸显；嘉靖以后，水灾呈现加剧的趋势，除固有的自然因素的原因外，过度围垦、民人渔利、修防低效等社会因素起着重要作用，同时，对圩田的治理有新的进展。圩田在皖南平原农业生产上具有重要作用。     

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.     

Estimation of Agricultural Production Functfons on a World-Wide Basis

Agricultural production is becoming increasingly capital and research intensive. Hayami and Ruttan, along with others, have developed and applied the metaproduction functional approach to the examination of this phenomenon on a worldwide basis. Limitations to the approach derive from a restrictive functional form chosen for estimation, and from a restrictive specification of agricultural capital and land. This study addresses those difficulties by use of the flexible translog functional form for estimation and by specifying an overall agricultural capital index and a land measure incorporating differences in the quality of land (agricultural natural resource) endowments. Estimation results indicate that agricultural comparative advantage in production is likely shifting to developed countries relative to LDC's due to capital constraints in the latter. Also agricultural potential (i.e., land endowments) do not serve to differentiate nations on the basis of agricultural production. Investment in agriculture, including land improvement, is key to the determination of comparative advantage. La production agricole fait appelle de plus en plus a beaucoup de re-cherches et de capitaux. Hayami et Ruttan, avec d'autres, ont developpe et appliqué l'approche fonctionnelle métaproduction pour examiner ce phénomena à l‘échelle du monde. Les limitations de cette approache provienneent de la forme fonctionnelle restrictive choisie pour l'estimation, et de la spécification restrictive de capitaux et terres agricoles. Cette étude traite ces difficultés en utilisant la formule “translog’ fonctionnelle adaptable pour l'estimation et en spécificant un indice du capital agricole global et une mesure de terre qui incorpore les différences du qualité des terres agricoles (ressources agricoles naturelles). Tous les résultats estimatifs indiquent que l'avantage comparatif agricole de production s'incline vers les pays développés parraport aux PMD dû aux constraintes de capitaux dans ces derniers. Aussi la capacité agricole (c'est à dire la richesse des sols) ne sert pas à différencier les nations sur le plan de production agricole. L'investissement dans l'agriculte, notamment l'amélioration de terre, est la cief pour déterminer l'avantage comparatif.     

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.     

油井水泥产品质量现状分析

结合2000～2005年对各油田油井水泥的质量监督工作，对我国油井水泥使用的标准、产品工艺、产品质量现状进行了分析。     

对我国取消农业税及相关问题的探讨

2004年起我国将在五年内取消农业税,并对粮食生产予以一定的补贴,这是我国税费改革中一件历史意义的大事,必将对我国农村经济的发展产生重大而深远的影响.为此,必须正确认识税费改革的意义,为要保证改革成功应坚持减轻农民负担、实事求是、走群众路线三条原则,正确处理各方面关系.     

A comparison of several approximations to the power function of the likelihood ratio test in covariance structure analysis*

In this paper we compare alternative asymptotic approximations to the power of the likelihood ratio test used in covariance structure analysis for testing the fit of a model. Alternative expressions for the noncentrality parameter (ncp) lead to different approximations to the power function. It appears that for alternative covariance matrices close to the null hypothesis, the alternative ncp's lead to similar values, while for alternative covariance matrices far from H_o the different expressions for the ncp can conflict substantively. Monte Carlo evidence shows that the ncp proposed in Satorra and Saris (1985) gives the most accurate power approximations.     

The mean-variance investment problem in a constrained financial market

This paper extends the mean-variance analysis and the two-fund separation theorem to a market with some constraints, such as, the incompleteness, prohibition of short-selling, and partial information, with stochastic interest rate, and with stochastic volatility for risky assets. By maximizing a quadratic utility of terminal wealth, we show that the efficient frontier for the problem is a straight line in the mean-standard-deviation diagram. The quadratic utility function exhibits mean-variance efficiency. Our results apply to portfolios of claims in a single period, multiperiod, and continuous time.     

转型与经济信息生产方式的演化创新

一定制度下的经济信息生产方式是决定其资源配置效率的重要基础。从制度或资源配置方式的转型角度,分析了经济信息生产方式与一定制度下资源配置的效率关系;指出与传统自由市场经济相对应的现行的会计、统计理论方法及其制度属于经济信息个体性生产方式,不适应以混合经济为特征的现代市场经济对经济信息的需求;最后以现代市场经济的混合经济特征为基点,从市场经济活动的广泛联系性、经济信息的公共物品性和满足社会需求出发,提出了建立经济信息社会化生产方式与制度模式的构想。