都市家庭农业:城市化危机、战略价值与支持体系

都市家庭农业在部分发达国家和发展中国家已成为一种普遍现象,并在城市食物供应系统和城市生态系统中占据极其重要的地位。进入21世纪以来,我国城市化的进程明显加快,城市化程度的大幅提升和城市规模的急剧扩张助推了能源、食物和生态三大战略性危机。都市家庭农业以其多功能性在缓解这些危机方面具有显著的战略价值。而推动我国都市家庭农业的发展需要一个以提供相关生产资料和技术服务的企业为基石的具有高度集成性和便捷性的都市家庭农业支持体系。     

关于中国商业银行营销战略体系的构建

为了在复杂多变的市场环境中求得长期生存和持续发展,中国商业银行必须以客户为导向,制定和实施适应市场需求的营销战略。中国商业银行构建的营销战略体系应包含：塑造多功能全方位的营销服务体系,打造类别系列化的营销产品体系,建立多层次立体化的营销渠道体系,建设高素质营销队伍体系,创建高品质的品牌营销体系。     

Does Work Always Pay in Germany?

Abstract. Income redistribution in Germany is the result of a combination of several redistribution instruments: there is a complex income tax law, different obligatory social insurances and supplementary benefits. This paper estimates income redistribution by quantile regression, using German EVS data. Two results are obtained: income after redistribution does not always increase in line with income before redistribution, i.e. for people with a low income before redistribution, it does not make sense to increase their efforts, since more work means less earnings. Further, an increasing redistribution rate for higher incomes is not always observable from the data.     

寡头竞争情形下的国企改革--论国有股份比重的最优选择

本文通过构建一个混合寡头垄断竞争的博弈模型 ,分别就封闭经济和开放经济的情形 ,探讨国企在背负一定的社会性负担的条件下 ,国企内部国有股份比重的变化如何影响整个社会的福利以及政府的支付。我们的基本结论是 :在国企相对生产效率很低的情况下 ,必须对其进行私有化改革 ;但是 ,如果国企的相对生产效率不太低 ,完全的私有化并不能最大化社会总体福利或政府支付。我们的基本结论可为政府当前国企改革的政策思路提供一定的理论支持。     

Communication in repeated network games with imperfect monitoring

I consider repeated games with private monitoring played on a network. Each player has a set of neighbors with whom he interacts: a player's payoff depends on his own and his neighbors' actions only. Monitoring is private and imperfect: each player observes his stage payoff but not the actions of his neighbors. Players can communicate costlessly at each stage: communication can be public, private or a mixture of both. Payoffs are assumed to be sensitive to unilateral deviations. First, for any network, a folk theorem holds if some Joint Pairwise Identifiability condition regarding payoff functions is satisfied. Second, a necessary and sufficient condition on the network topology for a folk theorem to hold for all payoff functions is that no two players have the same set of neighbors not counting each other.     

Non-implementation of rational expectations as a perfect Bayesian equilibrium

Summary. We point out several conceptual difficulties of the rational expectations equilibrium concept. In particular we show that such an equilibrium need not be incentive compatible and need not be implementable as a perfect Bayesian equilibrium . A comparison of rational expectations equilibria with the private core is also provided. We conclude that the private core is a more appropriate concept to capture the idea of contracts under asymmetric information.Received: 15 December 2003, Revised: 18 November 2004, JEL Classification Numbers: C71, C72, D5, D82. Correspondence to: Nicholas C. YannelisWe wish to thank Dr A. Hadjiprocopis for his invaluable help with the implementation of Latex in a Unix environment.     

Monetary policy with sticky prices and segmented markets

Summary. We consider a sticky-price model with segmented asset markets, and examine its implications for monetary policy. Our finding is, first, that the response of the money supply growth rate to a money demand shock required to stabilize inflation is not affected by the existence of a liquidity effect, but the response of the nominal interest rate is. Second, when the monetary authority adopts a Taylor rule, whether or not it should be active to obtain local determinacy of equilibria depends on the existence of a liquidity effect. Our results suggest that the monetary authority should be careful about the existence and the degree of a liquidity effect particularly when the nominal interest rate is used as the policy instrument.Received: 11 February 2004, Revised: 1 November 2004 JEL Classification Numbers: E3, E4, E5.     

Optimality of the competitive equilibrium in the Uzawa-Lucas model with sector-specific externalities

Summary. In this paper, we show that the competitive equilibrium is optimal in the Uzawa-Lucas model with sector-specific externalities associated to human capital in the goods sector. Thus, these external effects do not provoke a market failure and do not provide a rationale for government intervention.Received: 1 November 2002, Revised: 3 June 2003, JEL Classification Numbers: E62, H21, O41.I wish to thank Sandra López Calvo and an anonymous referee for their valuable comments. Financial support from the Spanish Ministry of Science and Technology and FEDER through Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (I+D+I) Grant SEC2002-03663 is gratefully acknowledged.     

Bounded rationality: static versus dynamic approaches

Summary. Two kinds of theories of boundedly rational behavior are possible. Static theories focus on stationary behavior and do not include any explicit mechanism for temporal change. Dynamic theories, on the other hand, explicitly model the fine-grain adjustments made by the subjects in response to their recent experiences. The main contribution of this paper is to argue that the restrictions usually imposed on the distribution of choices in the static approach are generically not supported by a dynamic adjustment mechanism. The genericity here is understood both in the measure theoretic and in the topological sense.Received: 29 April 2002, Revised: 11 February 2004, JEL Classification Numbers: C0, D7.I thank Peter Bardsley and Rabee Tourky for useful suggestions. Special thanks are due to an anonymous referee.     

SOE Reform under Oligopolistic Market Structure: The Optimal Choice of State Shares

This paper examines the effect of the change of state shares in a state-owned enterprise (SOE) on the efficiency of the whole society and the payoff of the government. This issue is addressed by setting up a mixed oligopolistic competition model and dividing the analysis into two cases: closed economy and open economy. The basic results are as follows: If the relative production efficiency of an SOE is too low, complete state ownership is not optimal, and privatization will be a necessary step; however, if the relative production efficiency of an SOE is not too low, complete privatization is not optimal both for the government and from the perspective of social welfare. The results can, to a certain extent, provide theoretical support to the governments idea on the SOE reform. Translated from Economic Research Journal, 2004, 1 (in Chinese)     

Towards a Multiperspectival Study of Borders

The paper develops a non-state centric approach to the study of borders, building upon Balibar's ‘borders are everywhere’ thesis. It offers a critique of the assumption of consensus (mutual recognition of borders) in border studies. It is argued that borders do not have to be visible to all in order to be effective. The case for a multiperspectival border studies is then outlined: borders cannot be properly understood from a single privileged vantage point and bordering processes can be interpreted differently from different perspectives. A key dimension of a multiperspectival approach to border studies is examined in detail: borderwork, societal bordering activity undertaken by citizens. This is explored at several UK sites in order to demonstrate the ways in which borders are not always the project of the state, that they can exist for some (but not all), and can link people to the world beyond the ‘local’ border.     

Job Protection versus Contracts At‐Will: Trading‐Off Entrenchment and Shirking

I compare two types of employment contracts: those offering job protection and at‐will contracts. Their respective performances reveal the following trade‐off: at‐will contracts provide cheaper incentives for agents not to shirk, but they can induce the opportunistic actions of agents to make themselves less dispensable (“entrenchment”). One implication of the model is that more senior managers, such as chief executive officers, should receive more protection, for example, through contracts that are explicitly not at‐will or contracts that specify a longer duration.     

Differing World-Views and Collective Action: The Case of Research

This essay combines constitutional choice and the sociologyof science. People do not only differ in preferences but alsoin worldviews. In order to steer research, society needs a basicsocial contract establishing a triple smallest common denominator.First: the provision with malleable resources is the best approximationto a common good to strive for. Second: formal procedures shouldbe used to determine the facts relevant to the question. Third:the maximization of malleable resources is the closest approximationto the incentives of those involved. If a hypothetical constitutionalassembly reaches an agreement on these points, it can designappropriate rules for research.     

Causality tests of budget and current account deficits: Cross-country comparisons

This study attempts to determine the causal relationship between budget and current account deficits as well as the direction of such causality. A selected sample of some developed and developing countries with annual time series data is used and cointegration techniques are applied to bring evidence regarding this important issue. Our results do not support any long-run relationship between the two deficits for developed countries while the data for developing countries do not reject such a relationship. However, our results suggest a causal relationship between the two deficits for most of the sample countries. First version received: November 1996/final version received: September 1998     

民营经济不是一个模糊概念

本文针对“民营经济是一个模糊的概念”之说，认为狭义的民营经济指个私等非公有制经济；广义的则除了个私经济外，还包括非国有经济中的公有制经济。民营经济概念并不模糊。之所以会认为它是个模糊概念，一是国务院对民营经济的概念至今尚未有一个科学，权威的界定；二是国家统计局也未建立起与民营经济概念相匹配的统计指标体系。     

Collusion in one-shot second-price auctions

Summary. Most of the literature on collusive behavior in auctions ignores two important issues that make collusion difficult to sustain at least in one-shot interactions: the detection of cheating and the verification of bids. Colluding bidders may deceive each other by using shill bidders. Also, if the identities of the bidders and their bids are not published then it would be difficult to verify the bid of a colluding bidder. This paper addresses these problems in one shot second price auctions where one bidder offers another bidder a side payment in exchange for not participating in the auction, while the number of other bidders is stochastic. In spite of the barriers to collusion mentioned above, a simple side payment mechanism which depends only on the auction price is introduced. It induces a successful collusion, eliminates the verification problem, provides no incentive for the use of shill bidders and guarantees that the proponent obtains ex-post non-negative payoff. The colluding bidders are ex-ante strictly better off compared with the competitive case, irrespective of their types.Received: 27 November 2002, Revised: 28 January 2005, JEL Classification Numbers: C72, D44, D82.Yair Tauman: Correspondence toWe would like to thank an anonymous referee for very valuable comments and suggestions that significantly improved the paper. We thank Shmuel Zamir for a helpful discussion.     

The Copeland rule and Condorcet’s principle

Summary. The purpose of this note is to shed some light on the relationship between the Copeland rule and the Condorcet principle in those cases where there does not exist a Condorcet winner. It will be shown that the Copeland rule ranks alternatives according to their distances to being a Condorcet winner.Received: 30 July 2003, Revised: 31 December 2003, JEL Classification Numbers: D70, D71.Christian Klamler: I am very grateful to Daniel Eckert and Nick Baigent for their helpful comments.     

Undecidability of the existence of pure Nash equilibria

Summary. The purpose of this paper is to show that for any positive integer n, there exists no algorithm which decides for each non-cooperative n-person game in strategic form with partially computable payoff functions whether it has a pure Nash equilibrium or not.Received: 20 March 2002, Revised: 23 April 2003, JEL Classification Numbers: C72.The author thanks the Referee and the Associate Editor for offering critical comments on this paper, which is dedicated to his brother Konstantinos Efstathiou Sofronidis.     

Asymmetric Information in Simple Bargaining Games: An Experimental Study

Bilateral bargaining situations are often characterized by informational asymmetries concerning the size of what is at stake: in some cases, the proposer is better informed, in others, it is the responder. We analyze the effects of both types of asymmetric information on proposer behavior in two different situations which allow for a variation of responder veto power: the ultimatum and the dictator game. We find that the extent to which proposers demand less in the ultimatum as compared to the dictator game is (marginally) smaller when the proposer is in the superior information position. Further we find informed proposers to exploit their informational advantage by offering an amount that does not reveal the true size of the pie, with proposers in the ultimatum game exhibiting this behavioral pattern to a larger extent than those in the dictator game. Uninformed proposers risk imposed rejection when they ask for more than potentially is at stake, and ask for a risk premium in dictator games. We concentrate on proposers, but also explore responder behavior: We find uninformed responders to enable proposers’ hiding behavior, and we find proposer intentionality not to play an important role for informed responders when they decide whether to accept or reject an offer by an (uninformed) proposer.     

Playing Cournot although they shouldn’t

Summary. In this note, we experimentally investigate the extended game with action commitment in a Cournot duopoly with asymmetric cost. Risk dominance considerations allow to select a unique equilibrium in which the low-cost firm is the Stackelberg leader. The data, however, do not support the theory as simultaneous-move play is modal. Average output choices are in line with the Cournot equilibrium. This suggests that Cournot is a much more robust predictor for competition in markets than theory suggests.Received: 14 October 2002, Revised: 1 December 2003, JEL Classification Numbers: C72, C92, D43. Correspondence to: Hans-Theo Normann