嵌入GVC的我国产业集群竞争力提升模式研究——基于“双钻石模型”

全球化生产网络的形成,片断化生产模式的发展,使得传统的产业集群在构建其区域经济系统时必须嵌入到全球的价值链(GVC)中,构建产业集群的全球竞争力提升模式。本文主要在波特钻石模型的基础上构建适合我国产业集群竞争力提升的双钻石模型,并且分析在GVC下国内钻石的变化趋势。在此基础上从双钻石模型的四个要素出发提出我国产业集群竞争力提升的路径选择。     

Statistical methodology for assessing homology of intronic regions of genes

We consider the problem of statistically evaluating the similarity of DNA intronic regions of genes. Present algorithms are based on matching a sequence of interest with known DNA sequences in a gene bank and are designed primarily to assess homology among exonic regions of genes. Most research focuses on exonic regions because they have a clear biological significance, coding for proteins, and therefore tend to be more conserved in evolution than intronic regions. To investigate whether the intronic features of genes whose expression is highly sensitive to environmental perturbations differ from genes that have a more constant expression, a collection of oncogenes, tumor suppressor genes, and nonregulatory genes involved in energy metabolism are compared. An analysis of the features of these genes' intronic regions result in clustering by regulatory group. In addition, Billingsley's test for Markov structure (1961) suggests that 67% of the intronic regions in this collection of genes show evidence of nonrandom structure, indicating the possibility of a biological function for these regions. The result of Billingsley's test for homology is used as input to a clustering algorithm. The biological significance of this methodology lies in the identification of groups based on the intronic regions from genes of unknown function. With the advent of rapid sequencing techniques, there is a great need for statistical techniques to help identify the purpose of poorly understood portions of genes. These methods can be utilized to assess the functional group to which such a gene might possibly belong.     

绵阳市干旱发生规律与预测

通过对绵阳市近500年来气候分析,发现气候干湿变迁有200年、20年等周期性。并用灰色系统的原理与方法,对本市干旱年景进行了预测,指出1992年前后,可能是本市解放以来第七个干旱年。     

有机硅产业群的形成及其启示

本文首先对产业集群研究的历史进行了回顾 ,列举了产业集群促进区域经济发展的若干实例。通过对江西星火工业园有机硅产业集群案例的实证分析揭示了产业集群的形成因素 ,探讨了地方政府在集群规划中的作用 ,并提出了地方政府应该采取的若干对策     

生命周期视角下与收入相关的健康不平等分析——基于组群分析的方法

本文利用中国健康与营养调查数据,从生命周期的视角对与收入相关的健康不平等的年龄特征和变动进行了基于组群分析的实证研究。研究结果表明：与收入相关的健康不平等随着年龄的增长不断扩大：不同年龄段的健康不平等均呈现不断扩大的变动趋势,45岁以上人群的变动幅度要相对大于45岁以下人群;教育、收入和医疗的不平等是与收入相关的健康不平等扩大的主要原因,但是对45岁以下人群健康不平等的影响要大于45岁以上人群;此外,本文还进一步分析了年龄老化对健康不平等变化的影响路径。     

跨国公司区位决定因素的变化--兼论作为东道国的发展中国家的政策思考

随着经济全球化和一体化进程的不断加快以及国际生产体系的不断完善,跨国公司对外直接投资在各国之间的分布呈不平衡的发展态势.这种地理分布格局的变化,标志着东道国投资环境以及推动国际生产区位选择的经济因素发生了改变,这反映出政策自由化、技术进步和企业战略三个层面的变化.所以,发展中东道国需要着力于产业群集、区位优势组合以及投资促进政策的发展,以便更好地吸引跨国公司和外国直接投资.     

Estimating the number of clusters

Hartigan (1975) defines the number q of clusters in a d ‐variate statistical population as the number of connected components of the set {f > c}, where f denotes the underlying density function on R^d and c is a given constant. Some usual cluster algorithms treat q as an input which must be given in advance. The authors propose a method for estimating this parameter which is based on the computation of the number of connected components of an estimate of {f > c}. This set estimator is constructed as a union of balls with centres at an appropriate subsample which is selected via a nonparametric density estimator of f. The asymptotic behaviour of the proposed method is analyzed. A simulation study and an example with real data are also included.     

Principal point classification: Applications to differentiating drug and placebo responses in longitudinal studies

Principal points are cluster means for theoretical distributions. A discriminant methodology based on principal points is introduced. The principal point classification method is useful in clinical trials where the goal is to distinguish and differentiate between different treatment effects. Particularly, in psychiatric studies where placebo response rates can be very high, the principal point classification is illustrated to distinguish specific drug responders from non-specific placebo responders.     

电子阅览室读者群的实证分析

以电子阅览室上机者为研究对象,对原始数据进行聚类和逐步拟合回归分析,研究结果显示:2004年6月份上机的读者群具有学习和娱乐两大特点.