Optimal designs for generalized linear models with biased response

This paper is concerned with the search for locally optimal designs when the observations of the response variable arise from a weighted distribution in the exponential family. Locally optimal designs are derived for regression models in which the response follows a weighted version of Normal, Gamma, Inverse Gaussian, Poisson or Binomial distributions. Some conditions are given under which the optimal designs for the weighted and original (non-weighted) distributions are the same. An efficiency study is performed to find out the behavior of the D-optimal designs for the original distribution when they are used to estimate models with weighted distributions.     

家电制造企业一体化销售物流模式的构建

针对家电制造企业设计了一体化销售物流模式,分析了这一模式下的各个子系统的功能设置,以及运用该模式的意义。     

Capacity Depreciation, Implicit Rental Price, and Investment Demand for Farm Tractors in Canada

Among the different factors pertaining to the demand for durable inputs in agriculture, the way the input depreciates over time is an important issue. This study investigates four alternative capacity depreciation patterns for farm tractors. While published estimates from government agencies implicitly assume convex capacity depreciation patterns, the results of this study demonstrate that the use of agricultural engineering data which depict a concave rather than convex pattern better reflect farmers' investment decisions. An implicit rental price measure is also proposed to account for the fact that the purchase price of a durable input is not an appropriate measure of the implicit rental cost of the asset.
Parmi les facteurs déterminants de la demande pour les biens durables en agriculture, la rapidité avec laquelle I'intrant se déprécie est certainement importante lors des décisions d'investissement. La présente etude analyse quatre différents scénarios de dépréciation pour les tracteurs agricoles au Canada. Bien que les données publiées par les agences gouver-nementales supposent implicitement que les biens durables se déprécient à un taux annuel constant, les résultats de cette etude montrent que I'utilisation de données basées sur la valeur productive de I'intrant telle que calculée sur une base expkrimentale donne de meil-leurs résultats statistiques dans I'estimation de la demande pour les tracteurs agricoles. De plus, une mesure du coût implicite de I'intrant est également proposée pour tenir compte du fait que le prix d'achat n'est pas une mesure appropriée dans I'analyse de la demande pour un bien durable.     

城市化进程中农村土地制度改革的构想

中国的基本国情是人多地少 ,土地是中国农民的主要生产资料和唯一的社会保障。文章在论述家庭土地承包经营对城市化进程的有利与不利两方面影响的基础上 ,提出稳定家庭土地联产承包制 ,调整承包期、界定土地产权关系、建立农民承包土地使用权流转机制、建立健全农村社会保障体系等农村土地改革和土地制度创新的构想     

“一家两制”差别化生产概念理论研讨分析

目的 农业生产源头关乎到农产品安全，当前学界就农产品“一家两制”差别化生产相关研究已产生较大学术影响，影响社会舆论对食品安全的判断。方法 文章以19个村庄的调研为基础，检视“一家两制”概念及其理论预设后发现，农产品“一家两制”的差别化生产并非普遍而只是个别现象，已有研究存在证据不足和社会误读等问题。结果 （1）自留地因素是农产品“一家两制”差别化生产的主要证据，但该文认为自留地作为特殊的历史产物不应被纳入农产品差别化生产研究范畴。（2）农产品有差别的生产方式并不完全是农户有意为之的行为，也有无意之举或农作习惯等因素。（3）多元理性的逻辑模型与当前农业生产现实并不契合，生存理性、经济理性和社会理性均难以有效解释农户农业生产行为。（4）“一家两制”理论存在消极的重建食品安全信任、对农户的道德谴责和加剧消费者不信任的弊端。结论 已有“一家两制”概念及其理论研究存在解释力和契合度不足等问题。食品安全治理需从多元主体出发，而不应单纯将农产品安全问题归因于小农户。     

中国碳排放权交易市场收益率波动性特征研究

以北京、上海、广东、湖北和重庆碳排放权交易市场为研究对象,运用GARCH族模型研究中国碳排放权交易市场收益率波动性特征。结果表明,5个碳排放权交易市场收益率的波动聚集性、持续性表现不完全一致;北京、上海和重庆存在负向的杠杆效应,广东和湖北不存在杠杆效应;从波动溢出效应关系看,5个碳排放权交易市场间的整体联动性不强;运用方差比率检验法得出,5个碳排放权交易市场均未达到弱势有效市场。这些特征反映出中国碳排放权交易市场的运行机制仍然存在缺陷,建议加强顶层设计,完善碳排放权交易体系。     

家庭农场退出诱发的利益冲突与化解策略研究

研究目的:借助埃奇沃斯盒状图阐述家庭农场退出的"帕累托改进"过程,深入分析家庭农场退出可能诱发不同主体间的利益冲突以及应对策略,为家庭农场的合理有序退出提供理论支撑。研究方法:经济学交换的一般均衡分析法、理论分析法、文献梳理法、综合分析法。研究结果:在家庭农场退出时,会在家庭农场主、农户、债权人、集体经济组织、家庭农场的其他成员等主体之间围绕土地合同违约、债务清偿次序、债务承担比例、资产处置等问题诱发激烈的矛盾冲突,这些问题的妥善解决对于构建家庭农场的合理有序退出机制、盘活退出家庭农场的整体资产、维护退出家庭农场主和债权人的合法权益都具有重要意义。研究结论:家庭农场退出所诱发的不同主体间的利益冲突应当依据法律政策、土地流转合同等科学合理地加以解决。对于家庭农场退出的资产采取整体转让、转租、托管经营等方式处理;明确家庭农场退出需要承担的法律责任,参照相关法律政策,明确家庭农场退出的债务偿还规则;明确集体经济组织在家庭农场退出时的职能定位;通过制定内部规章制度明晰家庭农场成员间的"权责利"关系格局。     

Off‐farm labor market decisions and agricultural shocks among rural households in Kenya

Using household level data from rural Kenya, this article explores whether and how farm households respond to unfavorable agricultural production environments, including any ex post adjustments in off‐farm labor supply in response to unexpected weather shocks. While controlling for a wide range of educational, demographic, and other locational factors, we examine how long‐term weather conditions and specific rainfall shocks influence a household's decision to engage in, and their earnings from, the off‐farm labor market. We find that rural households engage in off‐farm work as a long‐term strategy to deal with the effects of anticipated weather conditions on their farming operations. The analysis does not reveal major short‐term adjustments in off‐farm engagement as a result of specific, unexpected rainfall shocks; these households do however rely on remittance income and petty agricultural wage labor under these circumstances. Holding other factors constant, and conditional on participation, households in areas with a more productive local agriculture tend to earn more from off‐farm work especially in the informal/business sector than their counterparts in regions with a less productive agriculture. As expected, a vibrant local economy in the form of public investment increases the probability of off‐farm participation.     

Farm Poverty and Safety Nets

Farm families with incomes below the poverty line are far less likely than wealthier farmers to receive farm support payments. Using data from the 1989–2004 Current Population Survey, we find that poor farm families are also not participating in other assistance programs. Controlling for other factors, eligible farm families have substantially lower participation rates in the Food Stamp Program and in Medicaid than eligible nonfarm families. Removing farm safety net program payments would increase the number of farmers eligible for these programs but, in the absence of behavioral changes, would only lead to small increases in the number of recipients.