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31.
We offer a game-theoretic proof of Hamiltons rule for the spread of altruism. For a simple case of siblings, we show that the rule can be derived as the outcome of a one-shot prisoners dilemma game between siblings.JEL Classification: A13, C70, D64Correspondence to: Oded Stark, ZEF, University of Bonn, Walter-Flex-Strasse 3, 53113 Bonn, GermanyWe are indebted to an anonymous referee and to Uwe Cantner for helpful comments and suggestions. Partial financial support from the National Institute on Aging (grant RO1-AG13037) and from the Humboldt Foundation is gratefully acknowledged.  相似文献   
32.
This paper analyses the impact of foreign direct investment (FDI) on the development of local firms. We focus on two likely effects of FDI: A competition effect which deters entry of domestic firms and positive market externalities which foster the development of local industry. Using a simple theoretical model to illustrate how these forces work we show that the number of domestic firms follows a u-shaped curve, where the competition effect first dominates but is gradually outweighed by positive externalities. Evidence for Ireland tends to support this result. Specifically, applying semi-parametric regression techniques on plant level panel data for the manufacturing sector we find that while the competition effect may have initially deterred local firms’ entry, this initial effect has been outpaced by positive externalities making the overall impact of FDI largely positive for the domestic industry.  相似文献   
33.
We consider the M/M/1-queue and derive an explicit expression for the joint distribution of the number of arrivals and the number of departures in [0, t), given the number of customers initially present. The derivation is almost purely combinatorial, it avoids the use of generating functions, and immediately yields a simple probabilistic interpretation of the result.  相似文献   
34.
This paper shows how the interaction between decentralized information gathering and discreteness of investment decisions at the individual level can generate random fluctuations in aggregate investment that involve occasionally large allocation errors. This interaction is illustrated in a model in which private information is costly to acquire and prices reveal information. The unique rational expectations equilibrium outcome of the model is shown to always be noisy and characterized by investment levels which may be high simply because uninformed investors are buying under the impression that the high price is a signal of good investment opportunities.  相似文献   
35.
The general model of social learning with irreversible investment and endogenous timing is analyzed for any distribution of private informations. Strategic complementarities and multiple equilibria appear which are generated solely by information externalities. Different equilibria generate strikingly different amounts of information. The impacts of various assumptions (bounded beliefs, large number of agents, discrete time and short periods) are examined carefully. The properties are robust to the introduction of observation noise with a continuum of agents.  相似文献   
36.
This essay examines, from the perspective of both economics and ethics, the logical foundations of income transfers in a democratic society that allocates resources, in the large, through free markets. Such transfers, enacted through the public choice process, modify the market-determined distribution of income, as a reflection of the distributional preferences of the members of a society. Both constitutional and post-constitutional explanations of redistributions are considered. A discussion of recent experimental evidence of distributional preferences leads into a critique of simple equality, built on Michael Walzer's distinction between monopoly and dominance, as a criterion of distributive justice.  相似文献   
37.
In this paper we propose a sequential strategy, based on the microeconomic approach of the demand theory, in order to test for separability between private and public consumption. The aim of the present work is to verify, using a conditional almost ideal demand system, whether the different components of public consumption exert conditioning effects on the allocative structure of private spending. The empirical estimation of the model and the separability tests are developed for both a demand system in five functional categories of private spending, and for a demand system in six categories, where the private expenditures on those goods and services which can also be offered by the public sector are enclosed in a single functional category. The results of the separability tests, obtained using UK data for the 1974–2000 period, show that public individual consumption plays an important role in modifying consumer choices, while public collective consumption does not affect private consumption behaviours. The relationships between the different components of private spending and public individual consumption are both of substitutability and complementarity; in particular, we find that public individual consumption and the corresponding private expenditures on ‘Health, education, recreation and social protection’ are complements.  相似文献   
38.
岷江上游退耕还林的思考   总被引:2,自引:0,他引:2  
岷江上游不仅是长江上游生态屏障障的重要组成部分,更是成都平原的重要生态屏障和水源生命线,该区拥有丰富的水、生物、旅游等可再生资源,但在退耕还林(草)生态建设中表现出退耕面积扩大化、国家补贴政策一刀切、经济林比重过大等问题。文章指出,应在克服上述问题基础上,通过调整农村产业内部结构、加大坡耕地改造、发展旅游业、水电业以及加强变通、通讯设施建设是实现经济可持续发展的最佳选择。  相似文献   
39.
飞来峡电厂1#主变压器保护装置因超期服役、双重化配置要求和省网安评考核需要等原因进行技术改造。该文介绍了本次技改方案的内容,重点阐述方案对新增保护装置选型、配置的技术要求和具体实施过程,点明本次技术改造起到设备更新换代、提高安全系数和满足新形势需要的效果。  相似文献   
40.
为了揭示稻田不同节水灌溉与施肥管理方式下氮素迁移转化与利用损失规律,以指导水稻田的水肥管理,以水稻生育期田间水分氮素监测试验为基础,运用Hydrus-1D结合一阶动力学方法建立模型,对不同节水灌溉、肥料管理条件下的氮素运移进行模拟,并以反演的综合一阶动力学系数作为统一的评价指标,对不同方案处理下的氮素利用效率及环境效应进行分析评价。结果表明,植物吸收利用对于分蘖期、拔节孕穗期和抽穗开花期土壤水中氮素变化速率的影响比较显著;而氮素的主要损失差异在于分蘖肥和拔节肥导致的分蘖期和拔节孕穗期氨挥发损失效率大,以及分蘖期、抽穗开花期和乳熟期NO3-的反硝化作用造成的氮素变化差异明显;浅灌深蓄(G1)的NO3-综合一阶动力学系数较浅勤灌溉(G2)小,NO3-损失速率较小;施用氮肥(135 kg/hm2)(F1)施肥模式、(G1)灌溉模式下的植物吸收效率较另两种模式高,对应产量也较高;建议采用浅灌深蓄(G1)的节灌方式,同时采取分次施肥、深施等措施减少氨挥发损失,对于提高稻田氮素利用率尤为重要。  相似文献   
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