Optimal consumption and portfolio selection with negative wealth constraints,subsistence consumption constraints,and CARA utility

We consider the optimal consumption and portfolio selection problem with constant absolute risk aversion (CARA) utility. The economic agent in this model receives constant labor income, and her economic behavior is restricted on consumption and wealth, which are called the subsistence consumption constraint and the negative wealth constraint. We use the convex duality method to derive the value function and the optimal policies in closed-form solutions. Also we illustrate some numerical examples.     

Nonparametric estimation of multivariate extreme-value copulas

Extreme-value copulas arise in the asymptotic theory for componentwise maxima of independent random samples. An extreme-value copula is determined by its Pickands dependence function, which is a function on the unit simplex subject to certain shape constraints that arise from an integral transform of an underlying measure called spectral measure. Multivariate extensions are provided of certain rank-based nonparametric estimators of the Pickands dependence function. The shape constraint that the estimator should itself be a Pickands dependence function is enforced by replacing an initial estimator by its best least-squares approximation in the set of Pickands dependence functions having a discrete spectral measure supported on a sufficiently fine grid. Weak convergence of the standardized estimators is demonstrated and the finite-sample performance of the estimators is investigated by means of a simulation experiment.     

资源约束项目计划内在稳健性与资源使用效率关系

资源约束项目计划的内在稳健性受资源使用效率的影响,查明二者之间的影响关系,可为稳健性的项目计划制定和项目计划稳健性的预测提供依据。文章应用16种优先规则对Kolisch的j30算例集中的480个算例制定项目计划,计算出各项目计划的资源使用效率,通过仿真的方法得到各项目计划的内在稳健性值;实验结果表明,项目计划的内在稳健性与资源使用效率之间存在显著的负相关关系,即资源使用效率越高,项目计划的内在稳健性越低,这与直觉一致。     

乡村人居环境建设中的制度约束与优化路径

优化乡村人居环境,改善农户生活质量,统筹城乡发展是社会主义新农村建设的一项重要内容.目前我国乡村人居环境建设面临着基层组织管理制度、土地制度、户籍制度、投资制度和保障制度等方面的制度约束.针对一系列制度约束,从乡村人居环境建设内涵出发,构建了有利于促进乡村人居环境发展的新制度框架.应从创新农村市场经济制度,维护人居空间有序发展;完善财政转移支付制度,保障乡村人居公共物品供给;创新农村社区管理制度,重构乡村社会关系网络等方面进行制度创新.     

Understanding Sheng Nu (“Leftover Women”): the Phenomenon of Late Marriage among Chinese Professional Women

In the past few decades, there has been a rise in the number of single, unmarried Chinese professional women, which is known as the sheng nu or “leftover women” phenomenon. Through an interactionist grounded theory method, this study has located the interactional constraints faced by 50 single Chinese professional women that were issued by their male romantic partners and parents, respectively. “Discriminatory” and “controlling” gendered constraints issued by the women's male suitors and partners reflected the persistence of the Chinese patriarchal structure, and this was found to be the leading cause of the women being “leftover” in the marriage market. Parents' traditional views continued to exert strong influences on the women's marital choices, but this was seen to conflict with their more “modern” views toward advocating and supporting the women's strong economic achievements. The four different types of Chinese professional women that were constructed based on their different partner choice strategies not only gave rise to an in‐depth and nuanced understanding of the sheng nu phenomenon in China, but could also be generalized toward understanding the marital choices of single professional women in other patriarchal societies who faced similar dilemmas in reconciling interactional constraints imposed by men and parents alike.     

法律变迁的结构性制约——国家、市场与社会互动中的中国律师职业

对改革开放以来中国法律体系变迁根源的探讨,通常遵循国家主义的认识论,即国家意志主导甚至决定了法律体系变迁的所有方面。这种认识论虽然能够较好说明改革开放初期法律体系在中国的再造,但是未能全面把握当前的复杂情况。本文以律师职业在改革开放时期的变迁为例,利用定量数据和实证方法说明国家、市场和社会对法律体系的多重动态影响,提出法律变迁的“结构性制约”理论框架。改革开放以来中国法律体系变迁已逐步由国家主导的格局,演变成国家、市场、社会和法律体系之间相互直接和间接影响的格局。     

When Are Local Incentive Constraints Sufficient?

We study the question of whether local incentive constraints are sufficient to imply full incentive compatibility in a variety of mechanism design settings, allowing for probabilistic mechanisms. We give a unified approach that covers both continuous and discrete type spaces. On many common preference domains—including any convex domain of cardinal or ordinal preferences, single‐peaked ordinal preferences, and successive single‐crossing ordinal preferences—local incentive compatibility (suitably defined) implies full incentive compatibility. On domains of cardinal preferences that satisfy a strong nonconvexity condition, local incentive compatibility is not sufficient. Our sufficiency results hold for dominant‐strategy and Bayesian Nash solution concepts, and allow for some interdependence in preferences.     

我国粮食安全产业带建设:现实意义、约束条件与实施对策

国家粮食安全产业带是中央政府基于当前国内粮食安全形势和复杂国际形势科学研判提出的全新概念,不仅具有保障粮食安全、构建全产业链发展格局、优化粮食生产布局的深刻内涵,还具有提高粮食综合生产能力、促进粮食产业高质量发展、推进农业现代化发展的重大意义。为此,围绕“在哪建”“谁来建”“如何建”三大问题进行科学分析明确国家粮食安全产业带建设的地点、主体和重心,捋顺国家粮食安全产业带建设思路。研究发现当前国家粮食安全产业带建设面临着要素资源约束、内生动力不足、传统产业转型升级困难、区域协同发展不充分等问题。针对问题提出完善资源要素保障体系、发挥政策引导扶持作用、推动粮食产业转型升级、构建区域协同发展机制等对策建议。     

国际关系的理论回归与基础路径——以国际制度理论为例

国际关系理论衰落的论调和担忧激励了理论创新。在诸多创新方式中,理论综合是重要的一种,具体包含了理论折中和理论合成,且主要发生在宏观范式之间或内部,由此形成了四种主要的理论综合方式:范式间折中或合成、范式内折中或合成。理论合成的严格理论与理论折中的实用性分析框架之间,还存在较多模糊地带。更多的研究既没有清晰的理论创造或运用,亦没有明确的折中分析框架。但是,这并不意味着国际关系"理论已逝"的论断已成事实。在理论合成与理论折中之间还存在一种理论综合的方式——理论回归,即从相关的多层次和多学科理论中拟合出简约且共性最大(或平均差异最小)的基础路径。所谓"基础路径"即介于宏观哲学元理论或思想传统与具体学科内理论之间的、若干相邻学科或理论共享的、具有一定范围内共识性的研究议题及解答思路。以国际制度研究为例,大量的经验研究虽然时常没有明确的理论地位,但并未完全脱离多层次的理论基础,而是逐渐形成超越具体学科及/或理论的五大基础路径:权力—结构、理性—功能、文化—建构、历史—阶级、反思—批判。     

自然资源约束下的中国农业发展

农业生产是以自然资源为基础的活动,土地等自然资源仍然是发展中国家农业发展过程中最普遍的限制性因素。因此,自然资源禀赋不能被看做是既定的因素而忽视其作用。中国是世界上农业资源严重匮乏的国家之一。农业自然资源匮乏对中国农业生产率提高、农业经营规模扩大、农业产业结构调整等都有着很强的制约作用,进而影响着中国农业现代化的模式和进程。在自然资源约束条件下,中国农业发展的主要策略是加快农业技术创新,实现由资源型农业向科学型农业的转变;选择合适的农业经营方式,着重扩大农户外部经营规模;调整农产品贸易结构,出口劳动密集型农产品,换取土地密集型农产品;发展生态农业,建立农业可持续发展的新模式。