关于西部人才政策的几点思考

人才流动应符合经济规律。一个地区人才的数量和层次要适应该地区的经济总量和结构。西部开发对人才的需求以应用型为主,并以本地培养为主要途径。西部要特别重视少数民族各类人才的培养。     

Exact confidence regions for species assignment based on DNA markers

Assignment of individuals to correct species or population of origin based on a comparison of allele profiles has in recent years become more accurate due to improvements in DNA marker technology. A method of assessing the error in such assignment problems is présentés. The method is based on the exact hypergeometric distributions of contingency tables conditioned on marginal totals. The result is a confidence region of fixed confidence level. This confidence level is calculable exactly in principle, and estimable very accurately by simulation, without knowledge of the true population allele frequencies. Various properties of these techniques are examined through application to several examples of actual DNA marker data and through simulation studies. Methods which may reduce computation time are discussed and illustrated.     

Tempered Mittag-Leffler Lévy processes

In this article, we introduce tempered Mittag-Leffler Lévy processes (TMLLP). TMLLP is represented as tempered stable subordinator delayed by a gamma process. Its probability density function and Lévy density are obtained in terms of infinite series and Mittag-Leffler function, respectively. Asymptotic forms of the tails and moments are given. A step-by-step procedure of the parameters estimation and simulation of sample paths is given. We also provide main results available for Mittag-Leffler Lévy processes (MLLP) and some extensions which are not available in a collective way in a single article. Our results generalize and complement the results available on Mittag-Leffler distribution and MLLP in several directions. Further, the asymptotic forms of the moments of the first-exit times of the TMLLP are also discussed.     

Training needs of extension agents’ regarding organic agriculture in Saudi Arabia

The purpose of this study was to investigate the needs of extension agents for training on organic agriculture (OA) in the Riyadh Region. Fifty-five percent (n = 69) of extension agents were selected to collect data through an electronic survey. Results indicated that extension agents in the Riyadh Region cited on job training as a main source for acquiring knowledge in OA. Agents expressed interest in receiving training in OA in general, OA marketing, and transitioning to OA. The most useful resources were field days at organic farms, OA training sessions at colleges, and attending OA trial plots. There were no differences in the level of interest in training; however, there were significant differences between individuals in terms of their experience in OA, job responsibility for providing information related to OA, and area of specialization in their job. This study recommends developing professional training programs based on the current knowledge of extension agents.     

Subsampling-extrapolation bandwidth selection in bivariate kernel density estimation

This paper focuses on bivariate kernel density estimation that bridges the gap between univariate and multivariate applications. We propose a subsampling-extrapolation bandwidth matrix selector that improves the reliability of the conventional cross-validation method. The proposed procedure combines a U-statistic expression of the mean integrated squared error and asymptotic theory, and can be used in both cases of diagonal bandwidth matrix and unconstrained bandwidth matrix. In the subsampling stage, one takes advantage of the reduced variability of estimating the bandwidth matrix at a smaller subsample size m (m < n); in the extrapolation stage, a simple linear extrapolation is used to remove the incurred bias. Simulation studies reveal that the proposed method reduces the variability of the cross-validation method by about 50% and achieves an expected integrated squared error that is up to 30% smaller than that of the benchmark cross-validation. It shows comparable or improved performance compared to other competitors across six distributions in terms of the expected integrated squared error. We prove that the components of the selected bivariate bandwidth matrix have an asymptotic multivariate normal distribution, and also present the relative rate of convergence of the proposed bandwidth selector.     

On hysteretic vector autoregressive model with applications

This paper proposes a new hysteretic vector autoregressive (HVAR) model in which the regime switching may be delayed when the hysteresis variable lies in a hysteresis zone. We integrate an adapted multivariate Student-t distribution from amending the scale mixtures of normal distributions. This HVAR model allows for a higher degree of flexibility in the degrees of freedom for each time series. We use the proposed model to test for a causal relationship between any two target time series. Using posterior odds ratios, we overcome the limitations of the classical approach to multiple testing. Both simulated and real examples herein help illustrate the suggested methods. We apply the proposed HVAR model to investigate the causal relationship between the quarterly growth rates of gross domestic product of United Kingdom and United States. Moreover, we check the pairwise lagged dependence of daily PM2.5 levels in three districts of Taipei.     

Non-parametric estimation of reciprocal coordinate subtangent for right censored dependent scheme

The concept of reciprocal coordinate subtangent (RCST) has been used as a useful tool to study the monotone behavior of a continuous density function and for characterizing probability distributions. In this paper, we propose a non-parametric estimator for RCST based on the censored dependent data. Asymptotic properties of the estimator are established under suitable regularity conditions. A simulation study is carried out to examine the performance of the estimator. The usefulness of the estimator is also examined through a real data.     

基于DEA模型的京津冀科技与金融结合效率研究

由于金融业和科学技术的高度融合在较大程度上推动了中国经济社会的发展,科技与金融相结合发展已成为一种创新型发展趋势,文章借鉴现有的评价科技与金融结合效率的指标体系,运用数据包络分析模型对2005—2019年京津冀地区的金融投入与科技产出进行分析,研究其科技与金融相结合的效率,研究结果表明：在2019年京津冀三地科技与金融结合效率良好,均达到了有效状态,北京市科技与金融总体效率有9年未达到有效状态,天津市有13年未达到有效状态,河北省有12年未达到有效状态。根据研究结果,文章对京津冀地区科技与金融服务结合的未来发展提出建议。     

构建社会主义和谐社会与民族自治地方立法

如何构建社会主义和谐社会,这是目前我国民族地区共同面临的时代主题。本文从民族自治地方立法的视角对此进行研究,较深刻地阐述了民族自治地方立法与构建社会主义和谐社会的关系及其对构建社会主义和谐社会的重要作用。     

Population Density is a Key Factor in Declining Human Fertility

In studying the complex determinants of human fertility, social scientists have given little attention to population density, although reproduction has been shown to be density-dependent for a wide variety of other species. Using fixed effects models on the time series of 145 countries and controlling for key social and economic variables, we find a consistent and significant negative relationship between human fertility and population density. Moreover, we find that individual fertility preferences also decline with population density. These findings suggest that population density should be included as a variable in future studies of fertility determinants.