Some further aspects of the löwner-ordering antitonicity of the moore-penrose inverse

A survey is given of known proofs of the antitonicity of the inverse matrix function for positive definite matrices w.r.t. the Lowner partial ordering, and of the corresponding result for the Moore-Penrose inverse of nonnegative definite matrices [the theorem of Milliken and Akdeniz (1977)]. A short new proof of the latter result is obtained by employing an extremal representation of a nonnegative definite quadratic form. Another proof of this result involving Schur complements is also given, and is seen to be extendable to the case of symmetric (not necessarily nonnegative definite) matrices. A geometrical interpretation of Milliken and Akdeniz's theorem is presented. As an application, the relationship between the concepts of greater (maximum) concentration and smaller (minimum) dispersion is considered for a pair (class) of vector-valued statistics with possibly degenerate distributions.     

Quantile dispersion graphs to compare the efficiencies of cluster randomized designs

The purpose of this article is to compare efficiencies of several cluster randomized designs using the method of quantile dispersion graphs (QDGs). A cluster randomized design is considered whenever subjects are randomized at a group level but analyzed at the individual level. A prior knowledge of the correlation existing between subjects within the same cluster is necessary to design these cluster randomized trials. Using the QDG approach, we are able to compare several cluster randomized designs without requiring any information on the intracluster correlation. For a given design, several quantiles of the power function, which are directly related to the effect size, are obtained for several effect sizes. The quantiles depend on the intracluster correlation present in the model. The dispersion of these quantiles over the space of the unknown intracluster correlation is determined, and then depicted by the QDGs. Two applications of the proposed methodology are presented.     

关于分布函数的散布函数

研究了一种散布函数Ｄｘ（ｔ）的性质，得到了如下结论：设Ｘ～Ｎ（μ１，σ１２），Ｙ～Ｎ（μ２，σ２２），则Ｙ≤ＤＸσ２≤σ     

湍流模型和施密特数对街谷内污染扩散模拟的影响

选取不同的湍动施密特数,分别采用标准κ-ε模型和realizable κ-ε模型对孤立街道峡谷内的气流运动和污染物扩散进行了数值模拟.计算得到的气流速度场和污染物浓度分布表明,标准κ-ε模型和realizable κ-ε模型预测出极为相似的气流旋涡结构,即在峡谷内生成一个中心大致位于峡谷中央的顺时针大旋涡,并在此大旋涡的作用下污染物往峡谷的背风侧积聚.通过对比分析峡谷迎风面和背风面上的无量纲污染物浓度计算结果与风洞试验数据表明,湍动施密特数的改变并不影响计算空气流场,但改变污染物扩散方程中的湍动扩散率,增大湍动施密特数将减弱污染物的湍动扩散作用,使得峡谷顶部污染物外溢减少,从而导致峡谷内的污染物浓度计算值增大;只要给定合适的计算参数,标准κ-ε模型和realizable κ-ε模型均能预测出峡谷内的污染物扩散分布,标准κ-ε模型合适的湍动施密特数为0.4～0.6,而realizable κ-ε模型则为0.3～0.5;当取湍动施密特数为0.7(Fluent软件系统中的默认值)时,标准κ-ε模型的计算精度高于realizable κ-ε模型的计算精度.     

当前传播语境下传受主体的消解与重建

以web2．0和3G手机为代表的新媒体传播中,非专业化的私人传播日益扩大,很多方面已经超越了职业传播者的影响,传统意义上的传播者和受众的概念正在模糊化和彼此消解。这对传播的社会影响肯定会带来一系列新的问题。传统的新闻传播者要充分认识网络传播环境的特点,把传统优势和网络特征结合起来,在网络传播时代重建自己的话语主导权。     

工会发展与工资不平等： 美英工会的标准化工资率策略

从历史分析的角度看,工会和集体谈判对降低工资不平等有积极作用。美英两国的工会力量在过去一百年的发展中呈现出先增后降的倒U形趋势,与此同时,工资差距和收入不平等程度则呈同步反向运动。工会出于组织考虑、客观标准和工人团结的原因,在集体谈判中采用标准化工资率策略,提高了低工资者收入,压缩了工资分布范围,从而缩小了不平等程度。而我国存在集体合同覆盖率低、协商不充分等问题,为了改善我国收入不平等问题,需要进一步发挥工会在初次分配中的作用。     

Macroeconomic asymmetry in the Eurozone before and after the Global Financial Crisis: An appraisal of the role of the ECB

The launch of the euro in 1999 was assumed to enhance macroeconomic convergence among EMU economies. We test this hypothesis from a comparative perspective, by calculating different indices to measure the degree of macroeconomic dispersion within the Eurozone, the UK and the USA (1999–2019). We use common factor models to produce a single index for each monetary area out of different measures of dispersion. These indices can be used to inform on the degree of optimality of a monetary area. Our results show that macroeconomic dispersion in the Eurozone increased notably even before 2007 and it took significantly longer to return to pre-crisis levels, as compared to the UK and the USA. The paper shows the critical role played by the ECB’s asset purchases programmes in reducing macroeconomic divergences among EMU member states since 2015.     

Bayesian updating of atmospheric dispersion after a nuclear accident

Summary.  We consider a Bayesian forecasting system to predict the dispersal of contamination on a large scale grid in the event of an accidental release of radioactivity. The statistical model is built on a physical model for atmospheric dispersion and transport called MATCH. Our spatiotemporal model is a dynamic linear model where the state parameters are the (essentially, deterministic) predictions of MATCH; the distributions of these are updated sequentially in the light of monitoring data. One of the distinguishing features of the model is that the number of these parameters is very large (typically several hundreds of thousands) and we discuss practical issues arising in its implementation as a realtime model. Our procedures have been checked against a variational approach which is used widely in the atmospheric sciences. The results of the model are applied to test data from a tracer experiment.     

铁弗匈奴的族源、族称及其流散

铁弗匈奴是南匈奴去卑一支之后裔,因故逃归塞外之后,与迁居匈奴故地的鲜卑混居杂处而形成的一个新族体。其族称＂铁弗＂始于刘虎,源于北人谓＂胡父鲜卑母＂为＂铁弗＂。史书中有时称其为＂乌丸（桓）＂,是因拓跋魏将诸方杂人来附者谓之＂乌丸＂,至于与屠各之关系则是刘渊族源的衍生问题。夏政权灭亡之后,铁弗匈奴流散情况主要有三种：一是归入北魏;二是融入吐谷浑;三是继续保持＂刘＂姓活动在朔方地区。     

尼尔基水利枢纽工程粘性土分散性分析的研究

尼尔基水利枢纽位于黑龙江省与蒙古交界的嫩江干流上,工程基础可能存在分散性粘土。由于分散粘土对水利工程的危害极大,有必要对该工程使用的土料进行分散性鉴定。本文通过三种试验方法鉴定得出统一结论,判定该批土样为非分散性土。