Asymptotic properties of the maximum-likelihood estimator for a class of birth-and-death processes admitting a unique stationary distribution

The asymptotic properties of the maximum-likelihood estimator of the parameter vector for a class of birth-and-death processes admitting a unique stationary distribution are studied. Also, it is shown that identifiability of the parameter vector with respect to the likelihood implies that the Fisher information matrix is of full rank. Two special cases of biological interest are presented. One of these, the exponential birth-and-death process, is proposed as a more appropriate model of density dependence than the logistic process.     

论方壮猷的史学贡献——以武汉大学图书馆藏《元史讲义》为中心

武汉大学图书馆藏方壮猷《元史讲义》反映了他在元史研究领域的成就。方壮猷在元史领域的创见涉及蒙古族源问题,主要包括两个方面,一是系统论证蒙古源于东胡的观点,勾勒出蒙古族起源的路径;二是认为达靼与室韦可以混称,解决了蒙元史研究中的一个重要学术问题。方壮猷治史惯于以历史语言方法与史料考证相结合,十分重视使用新材料。其学术视野宽广,能够运用国际共通的专业语言,就国际学术界共同关心的学术问题进行研究、对话。     

试论国家利益的内涵与特征

国家利益是一国制定外交政策的重要依据,亦是一国对外交往与合作的重要参考。国家利益并不是随着国家的产生而产生的,而是在独立的民族国家出现后,在对外交往中逐渐形成了国家利益的雏形。国家利益和国家一样,具有阶级性和民族性。除此之外,国家利益还具有动态性的特点,会随着时代的发展而发展变化。从国家及其本质入手,阐述国家利益的起源、内涵及其特点,对国家利益的研究进行了一个基本的概述。     

从广西第五次人口普查看人口迁移状况

本文根据2000年人口普查10%数据带汇总的结果,认为广西人口迁移呈上升趋势,且增长速度较快;迁出人口远大于迁入人口。在迁移人口中,以劳动适龄人口为主,女性人口占多数,以初中文化程度最多,迁移者大多是商业、服务业人员,农林牧副渔水利业生产人员和生产、运输设备操作人员。务工经商是促成人口迁移最直接的动因。人口迁移是广西农村发展重要的资金来源和经济增长点,加快了广西城市化进程。但人口迁移产生了人口分布失衡、人才流失等负面影响。因此,我们应通过户籍制度改革、加强中心城市功能建设、制定和实施科学的人才流动政策等措施,促进广西人口迁移的良性运行。     

Time series models associated with Mittag-Leffler type distributions and its properties

ABSTRACT

We have provided a fractional generalization of the Poisson renewal processes by replacing the first time derivative in the relaxation equation of the survival probability by a fractional derivative of order α(0 < α ? 1). A generalized Laplacian model associated with the Mittag-Leffler distribution is examined. We also discuss some properties of this new model and its relevance to time series. Distribution of gliding sums, regression behaviors, and sample path properties are studied. Finally we introduce the q-Mittag-Leffler process associated with the q-Mittag-Leffler distribution.     

On the Choice of Functional Forms: Summary of a Monte Carlo Experiment

The use of flexible functional forms is a standard practice in applied econometrics. Many flexible forms have been proposed. In this study, we investigate the behavior of three of them—the translog, the symmetric McFadden, and the symmetric generalized Barnett. Based on Monte Carlo experiments, we assess the ability of these forms to test theoretical properties and to measure technological characteristics.     

Asymptotic Results for Spatial ARMA Models

Causal quadrantal-type spatial ARMA(p, q) models with independent and identically distributed innovations are considered. In order to select the orders (p, q) of these models and estimate their autoregressive parameters, estimators of the autoregressive coefficients, derived from the extended Yule–Walker equations are defined. Consistency and asymptotic normality are obtained for these estimators. Then, spatial ARMA model identification is considered and simulation study is given.     

Bayesian factor models in characterizing molecular adaptation

Assessing the selective influence of amino acid properties is important in understanding evolution at the molecular level. A collection of methods and models has been developed in recent years to determine if amino acid sites in a given DNA sequence alignment display substitutions that are altering or conserving a prespecified set of amino acid properties. Residues showing an elevated number of substitutions that favorably alter a physicochemical property are considered targets of positive natural selection. Such approaches usually perform independent analyses for each amino acid property under consideration, without taking into account the fact that some of the properties may be highly correlated. We propose a Bayesian hierarchical regression model with latent factor structure that allows us to determine which sites display substitutions that conserve or radically change a set of amino acid properties, while accounting for the correlation structure that may be present across such properties. We illustrate our approach by analyzing simulated data sets and an alignment of lysin sperm DNA.