Children and Demand: Direct and Non-Direct Effects

This paper examines the effects of children on demands. We employ a French family expenditure survey that has a number of unusual features to explore the source of the correlation between children and demands. The first sample we use is of older households which has information on completed fertility. The second sample is of younger households for whom we have family background variables. We find that children are not exogenous for some goods. These findings cast doubt on the usual practice of identifying direct children effects with the coefficients on the children variables in demand equations.     

Wavelet Threshold Estimators for Data with Correlated Noise

Wavelet threshold estimators for data with stationary correlated noise are constructed by applying a level-dependent soft threshold to the coefficients in the wavelet transform. A variety of threshold choices is proposed, including one based on an unbiased estimate of mean-squared error. The practical performance of the method is demonstrated on examples, including data from a neurophysiological context. The theoretical properties of the estimators are investigated by comparing them with an ideal but unattainable `bench-mark', that can be considered in the wavelet context as the risk obtained by ideal spatial adaptivity, and more generally is obtained by the use of an `oracle' that provides information that is not actually available in the data. It is shown that the level-dependent threshold estimator performs well relative to the bench-mark risk, and that its minimax behaviour cannot be improved on in order of magnitude by any other estimator. The wavelet domain structure of both short- and long-range dependent noise is considered, and in both cases it is shown that the estimators have near optimal behaviour simultaneously in a wide range of function classes, adapting automatically to the regularity properties of the underlying model. The proofs of the main results are obtained by considering a more general multivariate normal decision theoretic problem.     

组织学习的成本问题初探

组织学习的成本是知识管理研究和实践中不可忽视的重要问题。知识母体、知识的表现形式和知识交易费用等是影响学习成本的主要因素。核心知识高昂的学习成本是其独特性和价值性的经济学基础。以学习成本作为研究的切入点,学习的路径依赖性、知识转化的原因、核心能力的来源、企业战略选择和知识的资本属性,甚或管理学进步的经济学动因等问题都可望得到逻辑一致的解释。     

Analysis of changes of insect-plant ratio-improvement of key-factor analysis for evaluating bottom-up effects in insect population dynamics

A revised key-factor analysis was presented for analyzing the temporal changes in the ratio of insect absolute number to plant resource. Ten data sets for 5 insect species were then analyzed. In this key-factor analysis, the key factor is defined as the factor contributing highly to between-year variation inR _r , the log rate of the inter-year change of the insect-plant ratio. The yearly change of plant resource was handled as a separate factor, expressed byr _pl , log ratio of plant resource in yearn to plant resource in yearn+1. The following was revealed: 1) In 7 of the 10 data sets examined,r _pl influenced variations ofR _r ; in particular in 3 casesr _pl was the main key factor. 2) Generation-to-generation fluctuations of absolute insect densities showed density dependence in 4 cases, while those of insect-plant ratios, in 8 cases. 3) The Royama model or a linear model, explained well the relationship between log insect-plant ratio (X _r ) andR _r and the relationship betweenX _r and log yearly change rate of absolute insect density (R _abs ). However, in the 7 cases in whichr _pl was a critical factor for variations ofR _r , with, increase ofX _r ,R _r showed a steeper, decrease around the equilibrium point (the point for whichR _r is 0) thanR _abs . This occurred becauser _pl tended to be negatively correlated withX _r . Consequently, in two casesX _r fluctuated cyclicly or chaotically although without the changes in plant resource, fluctuations ofX _r would be damped oscillations approaching equilibrium.     

多层次激励系统可靠性的敏感分析

多层次激励系统的可靠性由各子系统的可靠性及它们之间的相互关系决定。激励系统可靠性灵敏度是测量激励系统可靠性对激励层次有效概率变化的反应程度。数学模型显示,激励的层次和路径依赖度是影响激励系统可靠性的关键因素。企业可以通过将激励资源优化配置给能带来最大增量效应的对象和改善上下级依赖关系2种方法来提高激励系统可靠性。     

Predictive Inference,Causal Reasoning,and Model Assessment in Nonparametric Bayesian Analysis: A Case Study

This paper continuesour earlier analysis of a data set on acute ear infections insmall children, presented in Andreev and Arjas (1998). The maingoal here is to provide a method, based on the use of predictivedistributions, for assessing the possible causal influence whichthe type of day care will have on the incidence of ear infections.A closely related technique is used for the assessment of thenonparametric Bayesian intensity model applied in the paper.Two graphical methods, supported by formal tests, are suggestedfor this purpose.     

认知语法中的中心成分

认知语法关于中心成分的论述具有跟其他语法理论不同的特点,涉及到两个基本概念：侧面定子和背景设置成分.由此而产生的两种中心成分其实是在不同层次上起作用的,背景设置成分是完整的名词短语和小句的最高层次上的侧面定子.在认知语法中,表示屈折变化的后缀和很多派生后缀也被分析为中心成分,这些中心成分跟作为中心成分的动词和介词一样,都是依附性的.     

Network public goods with asymmetric information about cooperation preferences and network degree

We propose a game theoretical model of one-shot network public goods formalizing the ‘closure argument’ that cooperation is more frequent in denser groups or networks. Equilibrium analyses show that (i) an ‘inefficiency problem’ exists: players all preferring mutual cooperation need not all cooperate; (ii) in dyads, groups and networks with degree independence, first order stochastic dominance shifts of the distribution of cooperation preferences or the degree distribution (weakly) increases cooperation, and (iii) the latter result does not hold for networks with degree dependence. Hence the closure argument always holds in networks satisfying degree independence but not in other networks.     

Weak ties and contact initiation in everyday life: Exploring contextual variations from contact diaries

This study examines how the significance of weak ties varies by contact initiation and purposes of contact in everyday life. Based on data from 55 contact diaries, we analyze the extent to which diary keepers judge each of 104,361 specific contacts as beneficial after they occur, by how well they knew the target person beforehand. Our hypothesis testing and bootstrap resampling show that when a diary keeper initiates a contact, weak ties result in more gains. In contrast, when the other party starts the contact, it is strong rather than weak ties that turn out to be more beneficial to the diary keeper. Such effects vary by other contextual factors, however, particularly the purposes of contacts.     

Economic Status,Family Dependence,and Health Outcomes of Older People in Western Rural China

There is a deficiency in empirical knowledge on the physical and mental health of lower-income older people with weak family support in western rural China. To address this research gap, this article uses the data from the 2014 China Longitudinal Aging Social Survey to analyze the disadvantaged situation of older people in western rural China through a regional comparative analysis. Our sample consisted of 7,138 older adults aged 60 or older in eastern and western, rural and urban China. We find that lower personal income is significantly associated with poor physical and mental health. Economic support from families means more for older people when they have a disability related to activities of daily living in western rural China. Fostering stronger family support networks might improve the mental health status of older people in western rural China. Our study suggests a broader scope for the state to play a greater role in economic empowerment and in the development of policies to effectively meet the present and future needs of older people in western rural China or other countries with an imbalance in the distribution of the aging population and welfare resources.