流动人口子女平等受教育权的应然与实然

流动人口子女平等接受教育,事关社会公平正义与安定和谐,是被国际法、我国《宪法》和有关政策法规确认的应有权利.然而当前流动人口子女受教育依然存在着入学条件不公正、难以平等享用公办教育资源、隔离教育、权利保障薄弱以及教育质量不高等问题,致使其平等受教育权大打折扣.只有从户籍、入学就学、财政投入、扶持民办教育、宏观规划、监督保障等方面加强制度改革与创新,弥补制度裂缝,才能从根本上解决流动人口子女平等受教育问题.     

Estimating the proportion of true null hypotheses, with application to DNA microarray data

Summary.  We consider the problem of estimating the proportion of true null hypotheses, π ₀, in a multiple-hypothesis set-up. The tests are based on observed p -values. We first review published estimators based on the estimator that was suggested by Schweder and Spjøtvoll. Then we derive new estimators based on nonparametric maximum likelihood estimation of the p -value density, restricting to decreasing and convex decreasing densities. The estimators of π ₀ are all derived under the assumption of independent test statistics. Their performance under dependence is investigated in a simulation study. We find that the estimators are relatively robust with respect to the assumption of independence and work well also for test statistics with moderate dependence.     

A comparison of two procedures to select the best binomial population with sequential elimination of inferior populations

We compare the selection procedure of Levin and Robbins [1981. Selecting the highest probability in binomial or multinomial trials. Proc. Nat. Acad. Sci. USA 78, 4663–4666.] with the procedure of Paulson [1994. Sequential procedures for selecting the best one of k Koopman–Darmois populations. Sequential Analysis 13, 207–220.] to identify the best of several binomial populations with sequential elimination of unlikely candidates. We point out situations in which the Levin–Robbins procedure dominates the Paulson procedure in terms of the duration of the experiment, the expected total number of observations, and the expected number of failures. Because the Levin–Robbins procedure is also easier to implement than Paulson's procedure and gives a tighter guarantee for the probability of correct selection, we conclude that it holds a competitive edge over Paulson's procedure.     

西北地区水资源短缺问题的反向思考

水资源的严重短缺已严重影响西部大开发的步伐。为解决这个问题,人们通常是沿着一种惯性思维,力主通过增加供给来满足西部大开发不断增长的水需求。运用供求动态平衡原理进行反向思考,有效解决西部水资源短缺问题的途径正是背道而行。只有通过适宜的制度安排,并压缩用水需求,才能达到供给与需求的动态平衡,使西部有限水资源得到优化配置和高效可持续利用。     

Probability and statistics: A tale of two worlds?

This comparative study of research productivity and publication habits in probability and statistics completes the paper that was published in this Journal at the end of 1997. It is based on a ten-year survey of eighteen international journals, half of which are specialized in probability theory and the other half in statistics. Paper, author and adjusted page counts yield cursory measures of productivity for countries and institutions that contributed to fundamental research in these two related fields during the period 1986-1995. These data also reveal significant cultural differences between probabilists and statisticians in the volume of research, the length of papers, coauthorship practices, etc. Canada is seen to be one of the strongest contributors to the development of these two disciplines.     

基于灰色统计方法的筒形件拉深缺陷分析与对策

本文基于灰色统计方法综合计算处理了多位冲压领域专家的意见,根据计算结果对筒形件拉深缺陷的解决方法按照重要程度排序,得出了一个制品缺陷与主要解决方法的对应顺序表,从而为筒形件拉深加工中克服缺陷的产生提供参考依据.     

西南民族地区乡城人口流动的推阻因素分析

本文根据人口流动的内在机理,从现阶段影响我国人口流动的大环境及西南民族地区的现实区情出发,分析了相关政策、经济发展水平、自然条件、人口特征等因素对西南民族地区当前乡城人口流动的推阻作用。     

俄罗斯远东联邦区的人口与移民问题研究

长期以来,俄罗斯联邦的人口与移民问题非常突出,主要原因是俄罗斯人口出生率低、死亡率高,已成为制约俄罗斯经济发展的重要因素之一.本文根据俄罗斯改革时期远东联邦区人口发展状况和区域人口再生产的趋势,分析了远东联邦区移民产生的原因、移民方向及其影响.提出了解决俄远东联邦区人口问题的措施.     

"沉默的螺旋"在传统大众传播环境和网络传播环境中表现方式的差异

“沉默的螺旋”是一种传统大众传播的强效果论。结合CMC(以电脑为媒介的传播)与FTF(面对面的传播)有关群体压力方面的研究成果,认为网络受众从众心理的动因继续存在,从众现象依旧普遍,因此,产生“沉默的螺旋”机制的基本条件在网络空间中仍然存在,并分析了“沉默的螺旋”在传统大众传播环境和网络传播环境中表现方式的差异。     

OPTIMAL SEMIPARAMETRIC INFERENCE FOR THE TAIL INDEX BASED ON RATIOS OF THE LARGEST EXTREMES

The k largest order statistics in a random sample from a common heavy‐tailed parent distribution with a regularly varying tail can be characterized as Fréchet extremes. This paper establishes that consecutive ratios of such Fréchet extremes are mutually independent and distributed as functions of beta random variables. The maximum likelihood estimator of the tail index based on these ratios is derived, and the exact distribution of the maximum likelihood estimator is determined for fixed k, and the asymptotic distribution as k →∞ . Inferential procedures based upon the maximum likelihood estimator are shown to be optimal. The Fréchet extremes are not directly observable, but a feasible version of the maximum likelihood estimator is equivalent to Hill's statistic. A simple diagnostic is presented that can be used to decide on the largest value of k for which an assumption of Fréchet extremes is sustainable. The results are illustrated using data on commercial insurance claims arising from fires and explosions, and from hurricanes.