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271.
In this article, we propose a new class of semiparametric instrumental variable models with partially varying coefficients, in which the structural function has a partially linear form and the impact of endogenous structural variables can vary over different levels of some exogenous variables. We propose a three-step estimation procedure to estimate both functional and constant coefficients. The consistency and asymptotic normality of these proposed estimators are established. Moreover, a generalized F-test is developed to test whether the functional coefficients are of particular parametric forms with some underlying economic intuitions, and furthermore, the limiting distribution of the proposed generalized F-test statistic under the null hypothesis is established. Finally, we illustrate the finite sample performance of our approach with simulations and two real data examples in economics.  相似文献   
272.
This paper develops a novel and efficient algorithm for Bayesian inference in inverse Gamma stochastic volatility models. It is shown that by conditioning on auxiliary variables, it is possible to sample all the volatilities jointly directly from their posterior conditional density, using simple and easy to draw from distributions. Furthermore, this paper develops a generalized inverse gamma process with more flexible tails in the distribution of volatilities, which still allows for simple and efficient calculations. Using several macroeconomic and financial datasets, it is shown that the inverse gamma and generalized inverse gamma processes can greatly outperform the commonly used log normal volatility processes with Student’s t errors or jumps in the mean equation.  相似文献   
273.
An often-cited fact regarding mixing or mixture distributions is that their density functions are able to approximate the density function of any unknown distribution to arbitrary degrees of accuracy, provided that the mixing or mixture distribution is sufficiently complex. This fact is often not made concrete. We investigate and review theorems that provide approximation bounds for mixing distributions. Connections between the approximation bounds of mixing distributions and estimation bounds for the maximum likelihood estimator of finite mixtures of location-scale distributions are reviewed.  相似文献   
274.
In this paper, we consider a statistical estimation problem known as atomic deconvolution. Introduced in reliability, this model has a direct application when considering biological data produced by flow cytometers. From a statistical point of view, we aim at inferring the percentage of cells expressing the selected molecule and the probability distribution function associated with its fluorescence emission. We propose here an adaptive estimation procedure based on a previous deconvolution procedure introduced by Es, Gugushvili, and Spreij [(2008), ‘Deconvolution for an atomic distribution’, Electronic Journal of Statistics, 2, 265–297] and Gugushvili, Es, and Spreij [(2011), ‘Deconvolution for an atomic distribution: rates of convergence’, Journal of Nonparametric Statistics, 23, 1003–1029]. For both estimating the mixing parameter and the mixing density automatically, we use the Lepskii method based on the optimal choice of a bandwidth using a bias-variance decomposition. We then derive some convergence rates that are shown to be minimax optimal (up to some log terms) in Sobolev classes. Finally, we apply our algorithm on the simulated and real biological data.  相似文献   
275.
中国生育率研究方法:30年回眸   总被引:1,自引:0,他引:1  
改革开放30年是我国人口学及人口研究迅速成长的30年。生育率研究方法从一个侧面反映出改革开放以来我国人口学研究方法的发展。中国的生育率研究方法既有从西方引进的各种生育率指标和模型,也有中国学者为了适应自己的需要而改进和创建的方法和模型。笔者从生育率度量指标和生育率模型两个方面总结我国生育率研究方法的应用及变化。对在中国生育率研究中所使用的主要方法进行回顾并对这些方法对我国生育率研究的贡献进行总结。  相似文献   
276.
上海市人口老龄化:现状、影响及对策思考   总被引:2,自引:1,他引:1  
骆勇  赵明强 《西北人口》2009,30(6):72-76
人口老龄化已成为当今世界各国经济发展过程面临的共同性话题,就上海而言.未来上海市人口老龄化带来的影响已逐渐凸显,人口老龄化带来的养老金匮乏,劳动力不足以及社区为老服务发展滞后的矛盾已开始成为制约上海市经济发展的瓶颈,老龄化带来的影响将在未来很长一段时间内长期存在.缓解人口老龄化带来的影响以及寻求可行性办法解决老龄化人口的赡养问题已成为政府和社会必须要解决的问题。  相似文献   
277.
日本行政法中的规制与规制的缓和   总被引:1,自引:0,他引:1  
规制在行政法中的必要性及功能早已确立。但是,随着行政权内涵的不断变化与时代要求的迥异,规制的法律理念、适用范围以及放宽等问题日渐凸显。本文从日本行政法中规制的内涵入手,就规制缓和的理念与规制的缓和进行分析;同时对规制的缓和之目标也有所涉及,以求对我国相关制度的建立与健全做些启示。  相似文献   
278.
There is still considerable uncertainty about how reproductive factors affect child mortality. This study, based on Demographic and Health Survey data from 28 countries in sub-Saharan Africa, shows that mortality is highest for firstborn children with very young mothers. Other children with young mothers, or of high birth order, also experience high mortality. Net of maternal age and birth order, a short preceding birth interval is associated with above average mortality. These patterns change, however, if time-invariant unobserved mother-level characteristics of importance for both mortality and fertility are controlled for in a multilevel–multiprocess model. Most importantly, there are smaller advantages associated with longer birth intervals and being older at first birth. The implications of alternative reproductive ‘strategies’ are discussed, taking into account that if the mother is older at birth, the child will also be born in a later calendar year, when mortality may be lower.  相似文献   
279.
Class participation is an essential part of the social work pedagogy. However, active student engagement in classes is inconsistent and varies based on factors such as social backgrounds, educational background, and individual characteristics. Instructors often evaluate participation based on frequency of verbal contributions. Evaluation criteria are often unarticulated or difficult to measure, presenting numerous challenges for instructors and students alike. A model of reflective self-assessment of participation by students, paired with timely instructor feedback is put forth in this paper to mitigate these concerns. The steps in this model include initial self-assessment, goal setting, midterm review, and a final review. The process of continuous self-evaluation and problem-solving is discussed as strategies that aid the process of class participation. Three instructor touch points are suggested: at the goal-setting stage, the midterm review, and the final grade. Throughout the paper, connections to social work practice and social work pedagogy are highlighted. This model has yet to be implemented in a social work school’s curriculum. Challenges in the implementation and resolution of those challenges are also presented. This model suggests ways to enhance opportunities for student engagement and integration into graduate programs, in addition to fostering valuable skills for future practice in the field.  相似文献   
280.
This paper illustrates the use of quasi-likelihood methods of inference for hidden Markov random fields. These are simple to use and can be employed under circumstances where only the model form and its covariance structure are specified. In particular they can be used to derive the same estimating equations as the E-M algorithm or change of measure methods, which make full distributional assumptions.  相似文献   
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