AIDS and agricultural production. Report of a land utilization survey,Masaka and Rakai districts of Uganda

Increased AIDS mortality and other preexisting conditions have contributed to agricultural productivity declines in the districts of Masaka and Rakai in Uganda. These two districts were the most fertile in Uganda and also had the highest HIV seroprevalence rates in Africa. 66% of study households experienced land use decline to some extent over the past 5 years. The 11% decline in poultry production and 32% decline in cattle production was reportedly due to poor management and loss of grazing land from overpopulation and larger scale farms. The most frequently reported reasons for crop reductions were death and sickness; these was estimated as affecting 8% of families with children under 5 years in the study area. Morbidity and mortality as a reason for the decline was reported two times as much as poverty and decline in international coffee prices. Other reasons for loss of productivity were food shortages and insecurity, loss of income, and reduced ability to respond to educational and medical needs. Cassava is replacing the culturally preferred matooke banana as a crop that is more disease-, pest-, and drought resistant. The banana weevil has been a recent problem. Marginal farming systems have been the most affected by declines in land use and livestock production, but fertile areas have not been spared the impact from AIDS and adult mortality. Poverty has decreased the use of pesticides, herbicides, and fertilizers in the districts. Policy has had an impact on agricultural practices: population growth and inheritance have added to loss of individual land holdings and contributed to fallow periods and infertility. Appropriate land management practices have not been adequately promoted in the agricultural extension service. Civil wars and the drop in coffee prices have reduced the number of farm laborers. Common grazing land has been turned over to large commercial ranches. Government should maintain research and monitoring of declines in food and cash crop production and manpower needs. Policy must be designed to respond to the complicated factors affecting productivity. High AIDS prevalence areas and marginal areas where reduced production effects would be the most severe must be given priority status. Development of cash crop alternatives must be examined and perhaps supported on an experimental basis by donor agencies. Maximum productivity should be encouraged by rural extension and education agencies. A number of other specific recommendations were made for individual survival strategies to maintain high agricultural productivity.     

伏尔加-卡马河水电梯级运行经验

介绍了俄罗斯欧洲部分的水电梯级开发,特别是建在伏尔加河及其最大支流卡马河上的11座大坝工程及多目标水库。讨论了平均建成时间有40a的这一水电梯级的运行与监测情况以及修复计划。     

失败过程中的不同阶段之——财务预测方法

财务指标被研究者广泛用于预测导向的统计模型中,其中一个应用方向便是预测企业的失败,研究的一般方法是评估一个基于财务指标的横断面模型去判定失败与非失败的企业。然而,评估横断面模型的隐含假设条件是失败过程在时间上是稳定的,这一假设常常被违反。有证据表明这些模型中的关系和参数不是稳定的。因此,这些模型,由于它们经常用的是失败     

An Agenda for Reforming Economic Theory

In this article, Nobel Prize Laureate Joseph Stiglitz argues that the standard macro-economic paradigm has failed not only to predict the crisis but also to provide insights into the design of a regulatory framework that would make a recurrence less likely. He points out that many of the underlying assumptions of the standard paradigm always seemed implausible and many of its predictions, such as those concerning the micro-economic behavior of the constituents (firms and households), are inconsistent with the empirical evidence. He then identifies a number of key modeling challenges, what he views as key ingredients that have to be incorporated in any model that is going to describe economic fluctuations or be the basis of a well-designed regulatory or monetary framework.     

观测仪器的设计和安装

现在,观测大体积土体和岩石特性公认的工程方法是使用专门的野外观测仪器.土工工程师为评估工程安全并作出较经济合理的设计越来越重视使用观测仪器.一般仪器(它的应用及相关问题)的概念已在设计和施工中得到广泛的认可.在应用中,所获得的数据量迅速膨胀、硬件激增,加之工业自动化,使大部分专业技术人员的知识显得落后.由于水工工程师对一个成功的观测仪器程序的所有组成部分的理解有限,因此,这些专业技术人员通常需要在大学里进行正规培训.因此,这里所介绍的只是如何缩短现存的知识沟.本文重点集中     

EVOLUTION OF SINGLE ELLIPTIC VORTEX RING

ABSTRACT:We study the evolution of single elliptic vortex ring for initial aspect ratio(AR)=2,4,6.The incompressible Navier-Stokes equations are solved by a dealiased pseudo-spectral method with 64~3 grid points in a periodic cube.We find that there are three kinds of vortex motion as AR increases and vortex bifurcation occurs at a certain AR.The processes of advection,interaction,and decay of vortex ring are analyzed.Numerical results coincide with experiments and other numerical simulations.     

跨国石油公司的作用

跨国石油公司已沾沾自喜地享受了百来年的美好时光。但现在,它们就象恐龙那样,随着岁月的消逝,前景越来越不美妙。动摇这些公司根基的是:在国外有民族主义的起而抗争;在国内,政府的管制日益严厉;还有世界公众日益增长的警惕和敌视。固然,在国际上展开跨国石油活动的先锋是大名鼎鼎的“七姐妹”,但现在已大量存在着独立于“七姐妹”之外但稍逊一筹的