农村留守老人生活满意状况考察

利用中国人民大学人口发展与研究中心2004年"农村子女外流对迁出地家庭养老的影响"抽样调查的数据,采用Logistic回归法,分析了影响留守老人生活满意状况的因素,定量考察了外出子女数量与留守老人生活满意状况的关系.研究结果表明,外出子女数量、留守老人自身的身体状况、家庭照料和赡养情况、是否感到孤独以及经济收入等因素对留守老人生活满意状况有显著影响,拥有更多子女外出的留守老人对生活满意的可能性要高于较少子女外出的留守老人.     

贵州农村人口老龄化现状、原因及影响

贵州省农村在经济相对落后的情况下进入年老型社会,特点是:人口老龄化程度高于城镇,引起这一现象的主要原因是男青壮年劳动力外流,老年人口数相对增大;高龄老人多且性别比失调;空巢和独居老人比重大。由于贵州农村经济发展滞后,将会造成总抚养系数偏高、代际关系恶化和医疗设施紧缺等不良影响。对此,必须采取大力发展经济、提倡家庭养老等四项措施。     

浅论高校基建工程无标底招标

当前高校的基本建设发展迅速,基建工程招标投标管理是合理确定建设工程造价和确保工程质量的重要环节。无标底招标作为一种由市场定价、企业依据自身实力自主报价的建设工程招标的新路子,在高校基建工程招标管理中的有效运作能够提高基建投资效益和保证建设工程质量。本文试就标底、无标底招标的含义作出解释,并对无标底招标中存在的若干问题进行探讨。     

Abstention as an escape from Arrow's theorem

There are non-dictatorial social welfare functions satisfying the Pareto principle and Arrow's independence of irrelevant alternatives when voters can abstain. In particular, with just seven voters, the number of dictatorial social welfare functions satisfying Arrow's conditions could be deemed, relative to the total number of social welfare functions satisfying Arrow's conditions, negligible.     

Nonparametric methods for deconvolving multiperiodic functions

Summary.  Multiperiodic functions, or functions that can be represented as finite additive mixtures of periodic functions, arise in problems related to stellar radiation. There they represent the overall variation in radiation intensity with time. The individual periodic components generally correspond to different sources of radiation and have intrinsic physical meaning provided that they can be 'deconvolved' from the mixture. We suggest a combination of kernel and orthogonal series methods for performing the deconvolution, and we show how to estimate both the sequence of periods and the periodic functions themselves. We pay particular attention to the issue of identifiability, in a nonparametric sense, of the components. This aspect of the problem is shown to exhibit particularly unusual features, and to have connections to number theory. The matter of rates of convergence of estimators also has links there, although we show that the rate-of-convergence problem can be treated from a relatively conventional viewpoint by considering an appropriate prior distribution for the periods.     

多子一定多福吗：子女数量与母亲健康

本文基于CHARLS 2013年全国追踪调查数据分析了已婚子女对母亲健康的影响。为了克服子女数量所带来的内生性,本文基于计划生育政策在民族和城乡之间的差别进行因果识别。研究结果表明,对于子女都已成家的母亲来说,子女数量的增加会显著降低偏瘦和低血压的概率,提高高血压的概率,总体上不会显著提高身体健康的概率。但是对于60岁以上的老龄女性而言,子女数量的增加会显著降低偏瘦、低血压和肥胖的概率,提高高血压的概率,并且在总体上会显著提高身体健康的概率。     

仿蔡氏电路中的分叉和混沌边界值——电路中黄金数的出现

本文根据Routh—Hurwitz判据,分析了仿蔡氏电路中分叉参数G和C_1的变化对其稳定区域的影响,并且导出了该电路不稳定现象消失时,电路参数须满足的条件α(?)C_2/C_1<(5 1/2-1)/2(G分叉)和β(?)C_2/LG~2<3-2 1/2(C_1分叉),从而避免了该电路中不稳定因素(包括混沌这种故障在内),达到确定故障边界的目的。另外,稳定条件的边界值α′=(5 1/2-1)/2恰好是黄金数。     

Continuous Time Wishart Process for Stochastic Risk

Risks are usually represented and measured by volatility-covolatility matrices. Wishart processes are models for a dynamic analysis of multivariate risk and describe the evolution of stochastic volatility-covolatility matrices, constrained to be symmetric positive definite. The autoregressive Wishart process (WAR) is the multivariate extension of the Cox, Ingersoll, Ross (CIR) process introduced for scalar stochastic volatility. As a CIR process it allows for closed-form solutions for a number of financial problems, such as term structure of T-bonds and corporate bonds, derivative pricing in a multivariate stochastic volatility model, and the structural model for credit risk. Moreover, the Wishart dynamics are very flexible and are serious competitors for less structural multivariate ARCH models.     

实数上限拓扑空间在拓扑教学中的应用

实数上限拓扑空间是一个简单、直观的拓扑空间．在拓扑学教学中，利用该拓扑空间可以淡化一些抽象的、逻辑性强的概念和理论，引导学生严密、深刻地思考问题，从而达到知识的完全理解和掌握．在总结教学经验的基础上，本文讨论实数上限拓扑空间在四个方面的应用．