Local influence diagnostics for incomplete overdispersed longitudinal counts

We develop local influence diagnostics to detect influential subjects when generalized linear mixed models are fitted to incomplete longitudinal overdispersed count data. The focus is on the influence stemming from the dropout model specification. In particular, the effect of small perturbations around an MAR specification are examined. The method is applied to data from a longitudinal clinical trial in epileptic patients. The effect on models allowing for overdispersion is contrasted with that on models that do not.     

Some maximum-indifference estimators for the slope of a univariate linear model

As known, the least-squares estimator of the slope of a univariate linear model sets to zero the covariance between the regression residuals and the values of the explanatory variable. To prevent the estimation process from being influenced by outliers, which can be theoretically modelled by a heavy-tailed distribution for the error term, one can substitute covariance with some robust measures of association, for example Kendall's tau in the popular Theil–Sen estimator. In a scarcely known Italian paper, Cifarelli [(1978), ‘La Stima del Coefficiente di Regressione Mediante l'Indice di Cograduazione di Gini’, Rivista di matematica per le scienze economiche e sociali, 1, 7–38. A translation into English is available at http://arxiv.org/abs/1411.4809 and will appear in Decisions in Economics and Finance] shows that a gain of efficiency can be obtained by using Gini's cograduation index instead of Kendall's tau. This paper introduces a new estimator, derived from another association measure recently proposed. Such a measure is strongly related to Gini's cograduation index, as they are both built to vanish in the general framework of indifference. The newly proposed estimator is shown to be unbiased and asymptotically normally distributed. Moreover, all considered estimators are compared via their asymptotic relative efficiency and a small simulation study. Finally, some indications about the performance of the considered estimators in the presence of contaminated normal data are provided.     

理论观照与实践反思:乡村振兴道路背景下产业融合探究

为从全球性现代化的视野观察中国现代化道路,通过在湖北西部（鄂西南、鄂西北）、渝东南、贵州（六盘水、遵义、黔东北等）等地烟草行业综合体建设进行调查,对城乡融合发展中的产业融合进行综合考察和研究。研究认为,中国的乡村振兴从“战略”提升为“道路”,表明中国式“两条腿走路”的三农现代化道路认知正式成形,乡村振兴道路在本质上讲是“农村就地现代化道路”,以农业为基础的农村就地现代化道路的关键是农村产业的融合发展;走乡村振兴道路,必须坚持政府是“主导”、乡村是“主场”、就地现代化是“主道”、产业融合发展是“主业”、内生发展是“主流”、三农工作队伍是“主体”、城乡等值发展是“主向”,再从土地流转关系、政策法规、主导产业培育、共享经济平台建设等方面,培育和推进乡村振兴中的产业融合工程。     

乡村治理与发展的协调路径

在乡村地区治理导向不断强化和发展自主权相对弱化的普遍趋势下,乡村振兴战略的提出凸显了治理和发展之间关系的不协调性。事实上,治理与发展关系的不协调并非现阶段独有的特征,而是具有理论意义和实践意义上的普遍性。另外,治理与发展关系的不协调程度不仅与基层组织体制的变动息息相关,从而呈现出不协调程度演变的阶段性;还与区域差异、地方差异以及村庄的类型有关,从而呈现出不协调程度的地方性。因此,要协调好乡村振兴过程中治理与发展的关系,就需要在认识到治理与发展不协调关系的普遍性、阶段性和地方性的基础上,按照权责利一致的原则理清乡村振兴中治理和发展关系再协调的基本思路。     

Rhetoric and Reality of Economic Self-sufficiency Among Rural,Low-Income Mothers: A Longitudinal Study

This study examined the contributions of maternal labor force participation and marital status on economic self-sufficiency over time for rural mothers. Data were from 174 rural families participating in three waves of data collection in Rural Families Speak. χ ² and multiple logistic regression were utilized. Results revealed only one-third of mothers moved toward economic self-sufficiency over three years. Maternal education, employment status, and weekly work hours were associated with improved economic well-being. Compared to single-parent families, unmarried-couple and married-couple families had increased odds of improving economically. In an analysis of all mothers with partners, married or unmarried, martial status was not significant in economic improvement. Findings suggest the role of marriage in welfare reform for rural families should be reconsidered.

Does the Euro–Mediterranean Partnership contribute to regional integration?

The paper investigates whether Southern Mediterranean and Middle Eastern markets under the Euro–Mediterranean Partnership (Egypt, Lebanon, Morocco, Malta, and Turkey) have become more financially integrated with the European stock market over time. The findings suggest that the Turkish equity market is moderately integrated with the European market, while the other economies exhibit weak financial integration with Europe, supporting the idea that the partnership appears to have no effect on enhancing inter-market linkages for these economies. Therefore, these markets would be good destinations for international investors seeking attractive investment opportunities to diversify their equity portfolios. Structural changes in the cross-market integration do exist, which may be considered as a guide for international equity portfolio diversification over different subperiods. In addition, there is evidence of an increasing trend in conditional correlations for Egypt and Turkey, to varying degrees, over time, notably during the post global financial crisis of 2007–2008, thus revealing herding behavior during this period. Overall, investors should be wary of the variation of equity market integration over time before engaging in an investment at the level of portfolio management and diversification. Policymakers must be aware of the remoteness of the current achievements of the Euro–Mediterranean Partnership from the targets set in terms of financial development and economic growth.     

A new estimator of Kullback–Leibler information and its application in goodness of fit tests*

We propose here a general statistic for the goodness of fit test of statistical distributions. The proposed statistic is constructed based on an estimate of Kullback–Leibler information. The proposed test is consistent and the limiting distribution of the test statistic is derived. Then, the established results are used to introduce goodness of fit tests for the normal, exponential, Laplace and Weibull distributions. A simulation study is carried out for examining the power of the proposed test and to compare it with those of some existing procedures. Finally, some illustrative examples are presented and analysed, and concluding comments are made.     

On approximations via convolution-defined mixture models

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.