美俄在叙利亚危机中的博弈策略分析——基于"重复囚徒困境"的视角

叙利亚危机从爆发至今已有六年多的时间,对于危机产生的原因以及危机进程中西方、中东各国与俄罗斯、叙利亚之间的博弈互动,国内研究更多集中在对于事件的定性之上,采用定量的方法研究叙利亚危机,目前来看还是比较少的.采用"重复囚徒困境"理论,对叙利亚危机期间,美国与俄罗斯围绕叙利亚所展开的一系列军事、政治、外交等方面的博弈进行分析,探讨美俄两国在叙利亚危机期间所采取的策略及其背后的动因可知,美俄两国在叙危机期间所采取的对策呈现出明显的"重复囚徒困境"模式,且两国所处的国际环境及其实力的不同决定了两国应对策略的差异化.     

热电偶综合实验改革与实践

培养和提高大学生实践动手能力、创新能力是实验教学的重要目标,是现代高等教育教学发展的客观要求,也是“卓越工程师教育培养计划”的内在要求。针对上海理工大学“动力工程测控技术实验”的教学目标,探索将热电偶标定实验设计为集热电偶制作、标定、自动化采集为一体的热电偶综合实验。实践表明,热电偶综合实验的改革与实践对提高教学质量,加强学生对综合知识的理解与运用,锻炼学生分析问题解决问题能力方面具有明显的效果。     

丙烯酰胺单体的缓聚合研究

针对丙烯酰胺(AM)及其衍生物在生产实际中易发生自聚的特点,很有必要研究一种阻聚剂来缓解此种现象。为此用沉淀法研究了1,4-对位苯醌、邻苯二胺、1,4-萘醌、吩噻嗪、对-叔丁基邻苯二酚五类物质在N2保护条件下,过硫酸铵作引发剂对丙烯酰胺自由基聚合产生的阻聚效应,考察了温度、加量对反应体系的影响。结果表明,在此五类物质中吩噻嗪对AM的自由基聚合产生较强的阻聚能力且对产物的分子量影响较小。     

油气管道沿线土壤腐蚀性的模糊物元综合评价

由于土壤腐蚀性的常规评价方法都是基于分级界线明确的多因素标准,往往漏失一些有用信息,甚至造成错误的结论。为此,基于模糊物元理论提出了金属管道沿线土壤腐蚀性的模糊物元综合评价的新方法。该方法的基本思路是:把模糊数学与物元分析相结合,利用模糊边界取代了常规的“清晰”边界,根据分析对象间的“相似性”的程度对其进行综合评价。该方法的关键在于:①确定土壤样品相应理化指标的隶属度;②确定各特征指标的权重复合物元;③确定关联系数复合模糊物元;④确定关联度复合模糊物元。与该方法相关的基本概念、理论及实施程序被阐明。通过四川新场气田-青白江输气管道沿线土壤的腐蚀性评价说明了其有效性。     

空间溢出视角下的生产性服务业集聚与长三角城市群经济增长效率

本文利用空间杜宾模型实证研究了生产性服务业集聚对长三角城市群经济增长效率的影响及空间溢出效应。结果表明,生产性服务业集聚不仅能够显著提升本地区的经济增长效率,还对邻近城市具有正向的空间溢出效应,但这种影响在生产性服务业的细分行业之间存在一定异质性。进一步分析发现,生产性服务业集聚的MAR外部性和Jacobs外部性都有利于长三角城市群经济增长效率的提升,而Porter 外部性对经济增长效率具有负面影响。在空间溢出效应方面,Jacobs外部性对经济发展水平相近的城市具有负向溢出效应,Porter外部性对人力资本水平相近的城市具有正向溢出效应。此外,生产性服务业与制造业协同集聚对本地区和人力资本水平相近城市的经济增长效率具有显著促进作用,但对邻近城市和经济发展水平相近城市的经济增长效率因“虹吸效应”而产生一定的抑制作用。这些研究,对如何更有针对性地加快提升长三角城市群经济增长效率,提供了有价值的理论依据。     

中国若干重要领域政府决策能力论析

作为一个在社会剧变中建立新政权,并且在其后较长时期内经济社会发展各方面仍处于较落后状态之大国政府,60余年来中国政府亟需回应之内外事务繁难急重,是对政府决策能力的持续压力与严峻挑战。钩深致远,鉴往知来。审视并反思在若干重要领域中政府决策能力的表现及其影响,探赜索隐,论其得失与因由,不惟有助于激浊扬清,汲取经验教训,探寻优化政府决策能力之路径与对策,促进政府决策能力的提升,亦利于学理之辨析与深化。     

A discrete probability problem in card shuffling

Abstract

There are n cards serially numbered from 1 to n. The cards are shuffled and placed in a line one after the other on top of a table with faces up. The numbers on the faces are read from left to right. If there are consecutive numbers in increasing order of magnitude the corresponding cards are merged into one. After the merger, the cards are numbered serially from one to whatever the number of cards we now have. The cards are shuffled and placed in a line one after another on top of the table with faces up. The process continues until we have only one card left. In this paper, we develop a probabilistic recurrence relation approach to obtain the mean, variance, and distribution of the number of shuffles needed. A Markov chain formulation and its properties are discussed in the paper as well.     

Estimation of Seemingly Unrelated Tobit Regressions via the EM Algorithm

An expectation-maximum (EM) likelihood algorithm is used to estimate two seemingly unrelated Tobit regressions in which the dependent variables are truncated normal. An illustrative example on the determination of the life-health insurance and pension benefits is also given.     

Parenting stress and behavior among single mothers of preschoolers: The mediating role of self‐efficacy

Abstract

This study examines the role of perceived self‐efficacy in mediating relations between mothers’ parenting behavior and variables such as maternal employment status, depressive symptoms, parenting stress, and child behavior problems. Subjects were 93 employed and 95 nonemployed, single, black mothers of a 3–5‐year‐old child who were current and former welfare recipients. Using linear structural relations modeling (LISREL), the findings support a model whereby (a) the more behavior problems the child is perceived to have, the more depressive symptoms the mother feels; (b) the more depressive symptoms the mother feels, the more likely she is to rate herself high in parenting stress; (c) the more depressive symptoms and parenting stress the mother experiences, the lower is the mother's estimate of her self‐efficacy; and (d) the lower the mother's self‐efficacy, the less competent is her parenting. The findings for employment status are similar; i.e., maternal employment predicted a trajectory leading to somewhat better parenting. In addition, child behavior problems were associated with less competent parenting both directly and indirectly through their effect on parenting stress and self‐efficacy. These results suggest that self‐efficacy has import as a mediator of the relations between maternal parenting and other psychosocial variables. There is no evidence, based on these findings, that employment in the low‐wage market is harmful either for single black mothers or their preschool children. However, job availability and an increase in the minimum wage are important policy considerations.     

西部大学生网络创业及其相关影响因素

近十年来,我国创业成功的大学生中,有四成以上选择了与IT密切相关的行业。为了解我国西部地区大学生网络创业软硬件环境及相关状况,课题组专门设计制作问卷,历时半年,主要针对西部六个代表性城市的31所大学中各种学历层次的大学生,共计发出了21683份纸质问卷,用充分的数据详细展示了目前我国西部地区大学生的网络使用状况,对于网络创业的认知态度和相关创业知识获取的渠道,现实难题和困境等问题,并在数据的基础上做出客观剖析评价,为相关网络创业教育和经济支持政策的制定提供了现实依据。