The importance of seasonal variability and tactical responses to risk on estimating the economic benefits of integrated weed management

Seasonal variability is an important source of risk faced by farmers and, regardless of an individual's attitude to risk, there are options to tactically adjust production strategies as the outcomes of risk become known. The objective of this article is to measure the economic benefits of alternative approaches to managing weeds, one of the most serious production problems in Australian cropping systems. A bioeconomic model that combines weed biology, crop growth and economics is developed to value the effects of seasonal variability and the role of tactical responses and sequential decision making in determining an optimal integrated weed management strategy. This shows that there are substantial differences in the measured long‐term benefits from deterministic and stochastic simulations. It is concluded that, for research evaluation of technologies that involve complex biological and dynamic systems, ignoring the impacts of seasonal variability, responses to risk and sequential decision making can lead to an incorrect estimate of the economic benefits of a technology. In this case study of optimal weed management strategies in Australia, the size of the error is high.     

Inverse of the Berge maximum theorem

Summary We consider an inverse of the Berge maximum theorem. We also give an application of our result to fixed point theory.     

IPv4与IPv6的比较

随着网络技术飞速发展,许多以IP为核心的网络新技术纷纷出现,IPv6就是其中一项很重要的技术,本文主要通过与目前IPv4存在问题的比较分析,从包头结构、地址格式及地址分类等方面来介绍IPv6的有关知识.     

两种标准条件下锦纶6帘线拉伸性能试验探讨

文章论述了分别采用GB/T9102-1988和GB/T9102-2003两种标准,对锦纶6浸胶帘线拉伸性能进行对比试验,并通过对对比试验结果的分析,推断出两组试验结果间的关系,从而为帘子布的生产、质量控制、检验和验收提供参考。     

Funded pensions and intergenerational and international risk sharing in general equilibrium

We explore intergenerational and international risk sharing in a general equilibrium multiple-country model with two-tier pensions systems. The exact design of the pension system is key for the way in which risks are shared over generations. The laissez-faire market solution fails to provide an optimal allocation because the young cannot share in the financial risks. However, the existence of wage-indexed bonds combined with a pension system with a fully funded second tier that pays defined wage-indexed benefits can reproduce the first best. If wage-indexed bonds are not available, mimicking the first best is not possible, except under special circumstances. We also explore whether national pension funds want to deviate from the first best by increasing domestic equity holdings. With wage-indexed bonds this incentive is absent, while there is indeed such an incentive when wage-indexed bonds do not exist.     

基于6sigma的采购质量改进研究

将6sigma的管理方法引入采购质量管理中,运用6sigma定义的DMAIC五个步骤对采购过程的质量进行定义、评估、分析、改进和控制,从而达到提高采购过程质量水平的目的。     

6-APA溶液物理化学特性的测定

6-氨基青霉烷酸(6-APA)是青霉素的母核,是半合成β-内酞胺抗生素生产的重要中间体。本文对于6-APA的溶液物理化学特性进行了分析与测定,其中包括溶解度、密度、粘度数据等,为6-APA工业化设计提供了依据。     

Does fiscal policy influence monetary policy? The case of Spain, 1874-1935

The Spanish peseta never formally belonged to the gold club, neither the classical nor the exchange-rate gold standards. It has been traditionally argued that the reason was the predominance of deficits in the Spanish budget from 1874 to 1935. The financing needs of the Treasury led to money creation and, consequently, to sacrificing the gold commitment and a fixed exchange rate. Applying a stationary VAR (Vector AutoRegressive) model, this paper estimates the dynamic link between budget and money and tests whether Spanish fiscal policy actually influenced monetary policy. The results confirm the dominance of fiscal policy for the period and, therefore, provide empirical support to the idea that the problems of the Treasury were behind Spain’s renouncement of gold.     

从现代管理理论发展看6 Sigma

本文通过对几种应用较为广泛的现代管理理论，如有关物流、成本管理的MRPn、ERP、Lean(精益生产)，及质量管理的QC、TQC、TOM、ISO9000进行回顾和比较。论述了这几种优越性及其理论存在的欠缺和不足。在此基础上，阐述了6Sigma理论的产生，对现代管理理论发展的贡献，及企业实施6 Siggma应具备的条件。