川西北高原藏区农村贫困化分异机制探测

[目的]客观揭示农村贫困化地域分异机制,为科学推进川西北高原藏区精准扶贫创新途径、综合战略和认真贯彻落实中央治藏方略提供参考依据。[方法]应用地理探测器模型、GIS空间分析与地统计方法等方法,探测川西北高原藏区贫困村单位面积GDP分异的主导因素,揭示农村贫困化分异机制,提出不同贫困化地域类型的扶贫政策措施。[结果]影响川西北高原藏区农村贫困化分异的主导因素包括到主要交通道路距离、归一化植被指数(NDVI)、土地利用、年均温度和海拔高程等,各因素对贫困村经济发展分异的解释力分别为80. 76%、12. 82%、8. 82%、5. 45%和3. 96%;贫困村经济发展贫困化的分异机制存在明显差异,可归纳为交通区位约束型、自然环境约束型和经济区位约束型等三大类型;农村贫困化驱动机制下的贫困村精准扶贫政策措施亟需因地制宜、科学推进、讲求实效,有序推进精准扶贫战略。[结论]精准扶贫应分类指导、重点突破,尤其加强贫困村交通、水利、公共基础设施建设和特色农牧业产业培植,注重多种扶贫模式的综合集成。     

Network neutrality and the nature of competition between network operators

The neutral architecture of the Internet is being challenged by various parties, such as network operators providing the connections to end-users, who are interested in gaining control of the information exchanged over the Internet. What are the effects on competition and welfare of such practices? Currently, there exists very little economic theory on network neutrality. This paper provides a preliminary analysis of the type of economic modeling that can address network neutrality, as well as of the type of results that can be expected.     

Quality Competition and Social Welfare in Markets with Partial Coverage: New Results*

We use a vertical product differentiation model under partial market coverage to study the social welfare optimum and duopoly equilibrium when convex costs of quality provision are either fixed or variable in terms of production. We show the following new results. First, under fixed costs, the social planner charges a uniform price for the single variant that just covers costs of quality provision. Like the duopoly equilibrium, this socially optimal pricing entails a partially uncovered market, but a smaller share of the market is served compared with the duopoly equilibrium. Second, for the variable cost case, it is socially optimal to provide both high‐ and low‐quality variants, but market shares need not be equal. This differs from the result in fully covered markets. Third, in the duopoly equilibrium, the quality spread is too wide under variable costs relative to the social optimum. Under fixed costs, the duopoly produces two variants, but quality is too low relative to the social optimum, which has only one variant.     

中国城市居住分异的制度成因及其调控——基于住房供给的视角

从住房制度、土地制度、税收制度等方面分析了加剧中国城市居住分异的制度性因素,并通过对国外及香港地区相关制度的分析,提出了对我国城市居住分异进行制度性调控的建议,即一方面要运用经济手段对住房市场进行干预和调节,另一方面要完善现有的住房供应制度,坚持住房有分异,分异有尺度,以利于社会的和谐发展.     

差异化战略:《新周刊》新锐之道

现在的杂志界“同质化”现象泛滥,许多刊物从封面到内容都是低层次重复。整个中国杂志界由于受体制的限制和束缚,存在创新意识和原创精神的缺失,难觅成熟的商业操盘。《新周刊》作为新闻时事杂志的“异类”,充分运用差异化战略,步步为营,闯出了一片新天地。文章从专题、封面设计、受众定位、经营方法等方面阐述了《新周刊》的差异化战略。     

Minimum Quality Standards under Asymmetric Duopoly with Endogenous Quality Ordering: A Note

In this note, we revisit minimum quality standards (MQS) under a vertically differentiated duopoly. We generalize the model in Ronnen (1991) and Valletti (2000) by introducing asymmetry into the fixed cost of quality improvement and by explicitly taking into account the endogeneity of quality ordering. In the generalized model, we show that the results derived by Ronnen (1991) and Valletti (2000) are largely robust.     

Free Entry under Uncertainty

When focusing on firm’s risk-aversion in industry equilibrium, the number of firms may be either larger or smaller when comparing market equilibrium with and without price uncertainty. In this paper, we introduce risk-averse firms under cost uncertainty in a model of spatial differentiation and show that the impact of uncertainty will increase the number of firms in an industry. With increased uncertainty, the risk premium of the marginal buyer increases by more than the risk premium of the average buyer, so that the price increases by more than the risk premium. When turning to the free entry game, we find that the market generates too many firms.     

Effect of credible quality investment with Bertrand and Cournot competition

We show how credible revelation and ability to commit to quality choice effect equilibrium qualities and welfare when product market is either Bertrand or Cournot competition. We show that results depend on the type of competition but not generally on the cost of quality function. We show that with Bertrand competition, the equilibrium qualities are lower with credible commitment. Competition is moderated and producer surplus is higher and consumer surplus lower. With Cournot competition, higher quality will be better but lower quality will be worse with credible commitment. Consumer surplus is always greater with credible commitment and if cost does not increase too quickly with quality, producer surplus will also increase. Thus credible commitment is a collusive device with Bertrand competition but it can improve social welfare with Cournot competition. Received: February 8, 2000; revised version: February 14, 2002 RID="*" ID="*" The idea of this paper originated in the weekly workshops of Mordecai Kurz at Stanford. I am forever in debted to Mordecai and fellow students – Luis Cabral, Peter DeMarzo, John Hillas, Michihiro Kandori, Steve Langois, Patrick McAllister, Steve Sharpe, Peter Streufert, Steve Turnbull and Gyu-Ho Wang – for their criticism and encouragement. I also benefited from comments from Yi-Heng Chen, Jin-Li Hu, Kala Krishna, Jinji Naoto, Thomas J. Prusa, and Shyh-Fang Ueng at various later stages of this work. Last but not least, I am grateful for the detailed comments of the referee.     

中国粮食生产区域分化特征和成因的实证研究

对中国在1990年和2002年粮食生产的区域分化状况进行统计分析的结果表明,工业化和城市化的发展,以及农产品市场形成条件下,稻米生产的区域分散特征、小麦生产的区域集中特征以及玉米播种面积的集中和生产产量的分散特征日益明显。计量检验显示,人均承包经营耕地面积和种植业收入比率是影响粮食生产区域分化的最主要的两个因素。     

Racing in two dimensions

In this paper we study an industry in which there is an ongoing sequence of R&D races between two firms. Firms are engaged in product innovation. Products are horizontally and vertically differentiated. There are two key characteristics/dimensions to products, and the level at which these are embodied in products can be increased by R&D. At each time firms can spend R&D on improving their product in one or both dimensions. We allow the possibility of economies scope — so R&D undertaken in one dimension can spillover to the other. The question we are interested in is whether a firm that is ahead in a single dimension but behind in another will focus all its R&D effort in the area in which it is ahead (product specialisation), or whether it will try to do R&D in both dimensions in the hope that it might get ahead in both and end up with a superproduct that dominates in both characteristics. The outcome of this R&D competition determines a Markov transition probability matrix determining the evolution of the industry. We show that when the R&D technology is characterized by constant returns then the only steady-state outcome is one in which the economy stays forever in a position in which one firm produces a super-product and the other gives up doing R&D altogether. This outcome is unaffected by the degree of economies of scope. When the R&D technology is characterised by decreasing returns, then the industry will visit all states and so will exhibit both product specialisation and superproduct dominance at various times. Now the extent of economies of scope matters and we show that the greater the extent of economies of scope, the less likely is the industry to exhibit product dominance, and the more likely it is to exhibit product specialisation.