陕西省自然、经济、社会条件及固定资产投资计划的调查分析

本文对陕西省自然、经济、社会条件及固定资产投资计划进行了分析 ,指出了陕西省的自然、经济、社会条件的优势及固定资产投资计划的特点。这对于陕西省政府有效实施其固定资产投资计划和实现其社会经济发展目标具有重要意义     

On pooling data summaries in the absence of interactions “response-by-study”

The standard hypothesis testing procedure in meta-analysis (or multi-center clinical trials) in the absence of treatment-by-center interaction relies on approximating the null distribution of the standard test statistic by a standard normal distribution. For relatively small sample sizes, the standard procedure has been shown by various authors to have poor control of the type I error probability, leading to too many liberal decisions. In this article, two test procedures are proposed, which rely on thet—distribution as the reference distribution. A simulation study indicates that the proposed procedures attain significance levels closer to the nominal level compared with the standard procedure.     

Almost Consistent Estimation of Panel Probit Models with “Small” Fixed Effects

We propose four different GMM estimators that allow almost consistent estimation of the structural parameters of panel probit models with fixed effects for the case of small Tand large N. The moments used are derived for each period from a first order approximation of the mean of the dependent variable conditional on explanatory variables and on the fixed effect. The estimators differ w.r.t. the choice of instruments and whether they use trimming to reduce the bias or not. In a Monte Carlo study, we compare these estimators with pooled probit and conditional logit estimators for different data generating processes. The results show that the proposed estimators outperform these competitors in several situations.     

增算子不动点定理及其应用

本文建立了若干新的增算子不动点存在定理,作为应用,作者研究了在Banach空间中一类含间断项Volterra积分方程解的存在性,我们的结果改进和推广了诸多已知结果。     

To be or not to be valid in testing the significance of the slope in simple quantitative linear models with autocorrelated errors

In this article, the validity of procedures for testing the significance of the slope in quantitative linear models with one explanatory variable and first-order autoregressive [AR(1)] errors is analyzed in a Monte Carlo study conducted in the time domain. Two cases are considered for the regressor: fixed and trended versus random and AR(1). In addition to the classical t -test using the Ordinary Least Squares (OLS) estimator of the slope and its standard error, we consider seven t -tests with n-2\,\hbox{df} built on the Generalized Least Squares (GLS) estimator or an estimated GLS estimator, three variants of the classical t -test with different variances of the OLS estimator, two asymptotic tests built on the Maximum Likelihood (ML) estimator, the F -test for fixed effects based on the Restricted Maximum Likelihood (REML) estimator in the mixed-model approach, two t -tests with n - 2 df based on first differences (FD) and first-difference ratios (FDR), and four modified t -tests using various corrections of the number of degrees of freedom. The FDR t -test, the REML F -test and the modified t -test using Dutilleul's effective sample size are the most valid among the testing procedures that do not assume the complete knowledge of the covariance matrix of the errors. However, modified t -tests are not applicable and the FDR t -test suffers from a lack of power when the regressor is fixed and trended ( i.e. , FDR is the same as FD in this case when observations are equally spaced), whereas the REML algorithm fails to converge at small sample sizes. The classical t -test is valid when the regressor is fixed and trended and autocorrelation among errors is predominantly negative, and when the regressor is random and AR(1), like the errors, and autocorrelation is moderately negative or positive. We discuss the results graphically, in terms of the circularity condition defined in repeated measures ANOVA and of the effective sample size used in correlation analysis with autocorrelated sample data. An example with environmental data is presented.     

固定效应部分线性变系数面板模型的快速有效估计

本文将最小二乘支持向量机(LSSVM) 和二次推断函数法(QIF) 相结合，为个体内具有相关结构的固定效应部分线性变系数面板模型提供了一种新的快速估计方法；在一定的正则条件下，论证了参数估计量的渐近正态性和非参数估计量的收敛速度；采用Monte Carlo模拟考察了估计方法在有限样本下的表现并将估计技术应用于现实数据分析。该方法不仅保证了估计的有效性和统计推断力，而且程序运行速度得到较大幅度提升。     

Acceptance of homosexuality through education? Investigating the role of education,family background and individual characteristics in the United Kingdom

Higher educated people tend to be more accepting of homosexuality than lower educated people. This has inspired claims that education leads to a higher acceptance of homosexuality. Alternatively, the association between education and acceptance of homosexuality could be confounded by (un)observed family background and stable individual characteristics. This study investigated the association between education and acceptance of homosexuality and the role of potential confounders in a unique longitudinal sample of British siblings. Multilevel and fixed effects analyses show that both perspectives apply. A large part of the association between education and acceptance of homosexuality could be attributed to family background and observed individual characteristics (one third), as well as unobserved individual characteristics (an additional third), but the positive association remains. Findings are discussed in light of existing explanations regarding the effect of education on the acceptance of homosexuality.     

禽流感风险、多元化经营与中国养禽户家庭生计研究

现有研究普遍认为禽流感的发生会对养禽户家庭生计造成严重负向冲击,而统计数据显示禽流感发生之后养禽户家禽收入显著下降,但家庭收入仍呈上升趋势。 基于农村固定观察点 2 520 个养禽户 2004—2012 年家禽养殖跟踪数据,本文采用固定效应模型,分析禽流感冲击下养禽户家庭生计变化,探讨禽流感、多元化经营与中国养禽农户家庭生计之间的关系。 结果表明,禽流感的爆发确实对家禽养殖农户生计造成了巨大的冲击,但多元化经营可以削弱禽流感对养禽户家庭经营收入的负向影响,且相比于种植业,养禽户更倾向于通过增加畜牧业投入和非农就业投入来避免禽流感造成的家庭经营收入波动。 我国现有禽流感补偿政策仅按照扑杀数量发放,为制定更为精准的扑杀补偿标准和灾后扶持政策,应关注禽流感对养禽户生计冲击的农户异质性,充分考虑养禽户多元化经营状况,扩大政策关注范围,正确引导农户进行兼业经营。     

Evaluating the Use of Spatial Covariance Structures in the Analysis of Cardiovascular Imaging Data

This article investigates the choice of working covariance structures in the analysis of spatially correlated observations motivated by cardiac imaging data. Through Monte Carlo simulations, we found that the choice of covariance structure affects the efficiency of the estimator and power of the test. Choosing the popular unstructured working covariance structure results in an over-inflated Type I error possibly due to a sample size not large enough relative to the number of parameters being estimated. With regard to model fit indices, Bayesian Information Criterion outperforms Akaike Information Criterion in choosing the correct covariance structure used to generate data.     

医疗保险对农村居民家庭消费的影响分析--基于不同收入层级的跨地区比较

利用2009、2010农村固定观察点数据,分析了医疗保险对不同地区、不同收入层级的农村居民家庭医疗消费支出和非医疗消费支出的影响。实证结果表明：医疗保险对农村居民家庭的医疗类消费不存在显著影响,对非医疗类消费支出则存在显著的正向促进作用。分地区来看,医疗保险对东西部地区农村居民家庭医疗类消费的影响差异显著,对东中部地区农村居民家庭非医疗类消费支出的影响同样差异显著;分收入层级来看,医疗保险对家庭医疗类消费的影响在不同收入层级的农村居民家庭之间不存在显著差异,但对非医疗类消费支出的影响在不同收入层级之间差异显著。此外,商业医疗保险作为医疗保险体系的重要组成部分,对促进农村消费起到带动作用。最后,本文从加大政府补贴和完善保障机制两个方面提出政策建议以期有效降低农村居民家庭超常的预防性储蓄,促进农村居民家庭消费。