Ecological Transfers in Non-Human Communities Parallel Economic Markets in a General Equilibrium Ecosystem Model

Synopsis: The oft-cited analogies between ecological and economic systems are exploited to develop a many-species model of population dynamics. In economies, markets are the fundamental institutions in which the interaction of demands and supplies determine the quantities and prices of goods. However, economic markets are not appropriate for ecological communities, because markets rely on voluntary exchange, whereas plants and animals engage in involuntary transfers of biomass. A properly defined counterpart to markets based on biomass transfers permits a general equilibrium model of predator/prey and competitive interactions in a many-species community. Functional response from optimal foraging and predation risk provide the demand and supply, respectively, in the biomass transfers. Energy per unit time is scarce and predators and prey make optimum choices with respect to functional response and risk avoidance based on required energy expenditures. The energy expenditures are similar to economic prices: they determine foraging strategies and are beyond the control of the predators and prey, yet they are determined by the aggregate choices of all predators and prey and by population densities. The energies acquired from foraging are used in a new way to construct difference equations that determine the population dynamics. This revised version was published online in July 2006 with corrections to the Cover Date.     

政府国库资金、货币供给与货币政策有效性

政府财政行为对货币政策效应的影响是宏观经济学的一个热点问题,文章从政府资产角度出发,运用1994～2005年中国国库资金季度数据,采用协整分析方法对政府国库资金、货币供给和货币政策有效性问题,作实证检验。研究表明:(1)国库资金增减导致基础货币收缩和扩张,短期内国库资金变动会使货币供应量发生显著的反向波动,国库资金是货币供应量的Granger因,国库资金对货币供应量波动有较高的解释力,央行的货币供给由于国库资金而产生被动性。(2)国库资金与货币政策有效性之间存在密切关系,货币当局将国库资金变量纳入货币政策中介目标监控体系,有助于提高货币政策的有效性,国库资金成为财政政策与货币政策新的结合点。     

国际资本流动对中国货币政策影响的实证研究

在开放经济的"三元冲突"中,中国选择了固定汇率,较严格的资本管制和较大的货币政策独立性,即用少量货币政策独立性的丧失换取有限度的资本流动.但在这种组合下,随着我国资本流动规模的扩大,货币政策独立性也将进一步丧失.对于中国,货币政策的自主权至关重要,除非有能力继续维持更严格的资本管制,我国必须逐步扩大汇率的浮动区间.     

大型工程建设项目的供应物流模式选择研究

首先介绍了工程建设项目的物流特征，然后分析了工程建设项目供应物流的几种现行模式及其优缺点，在此基础上，进一步分析了大型工程建设项目供应物流模式选择的影响因素，提出了大型工程建设项目供应物流的“代建单位供材制＋第三方物流”模式和“总承包商供材制＋第三方物流”两种基本形式；     

两阶段订购模式下的供应链契约协调

本文针对短生命周期产品需求的不确定性,建立允许调整订货量的两阶段订货模型,由此得到销售商应该采取的最优订货量.在此基础上,运用契约协调机制,从而达到供应链的协调.     

基于复杂网络理论的供应链应急管理研究

基于复杂网络理论研究供应链应急管理,提出了运用复杂网络理论,可以帮助评价供应链网络的结构,衡量网络的效率,识别供应链网络中的关键节点,从而能够有效地对供应链网络进行防护,同时对将来的研究方向作了展望。     

供应链风险分析及决策模型

供应链管理对企业参与市场竞争有诸多优势,但由于市场的不确定性、合作企业信息的不对称性及其他随机因素的影响导致供应链存在很大风险.笔者分析了供应链基于成本型的风险因素,并根据不确定多属性决策理论提出了供应链决策模型.     

基于SCOR模型的供应链流程管理架构研究

从企业流程建模的理论出发,对SCOR模型加以扩展,提出了一个基于SCOR模型的供应链流程管理建模架构,描述了该架构的组成要素以及各要素间的联系,为供应链流程管理提供了模型支持。     

我国金融物流模式探析

“十一五”规划纲要明确提出：要“大力发展现代物流业.”本文根据国外金融物流比较成功的经验,以及我国目前第三方物流的现状,创新地提出了我国第三方物流发展金融物流模式,从而有效地降低物流成本、加速资金周转、促进我国物流企业的发展.     

Interindustry Linkages: Virtuous and Vicious?

Although overall linkages are steadily increasing in growth processes, em-pirical data supply strong evidence of large intercountry and intertemporal fluctuations of the domestic-to-overall linkages ratio. This paper tries to explain this phenomenon by modelling a producers' behaviour which appears more realistic than that usually assumed in interindustry or computable general equilibrium models. The main novelty of the results is that the same causes that generate interindustry multipliers can also ‘trap’ domestic linkages into reinforcing (‘virtuous’) or weakening (‘vicious’) circles, depending on whether the price competitiveness of domestic activities is above or below a threshold related to the non-price competitiveness of those activities. These results can help to explain the fluctuations of domestic linkages with respect to overall linkages by spatial and temporal shifts of the threshold between the vicious and the virtuous ‘areas’. Moreover, they emphasize the importance of supply policies-mainly R&D policies—because of their ‘pushing down’ effect on this threshold.