Defining the linear portion of a sigmoid‐shaped curve: bend points

Formulae are provided that define the ‘bend points’, the beginning and end of the essentially linear dose–response region, for the four‐parameter logistic model. The formulae are expressed in both response and dose units. The derivation of the formulae is shown in order to illustrate the general nature of the methodology. Examples are given that describe how the formulae may be used while planning and conducting bioassays. Copyright © 2003 John Wiley & Sons, Ltd.     

论社会主义市场经济的本质在于“四个坚持”

关于对社会主义市场经济的认识,一般人都从经济运行方式的角度去考察,揭示社会主义市场经济的运行规范和某些功能,而对于社会主义市场经济的本质问题缺乏哲学和理论思考,没有从根本上揭示社会主义市场经济的本质是什么。探讨社会主义市场经济不能只停留在社会主义市场经济的基本职能和功能,而不重视社会主义市场经济的本质问题;不能只停留在社会主义市场经济的基本表现,而忽视社会主义市场经济的本质特征。社会主义市场经济的本质在于“四个坚持”,即坚持社会主义道路、坚持无产阶级专政、坚持党的领导、坚持马列主义毛泽东思想。     

Expected sample moments of concomitants of selected order statistics

In this paper, the task of determining expected values of sample moments, where the sample members have been selected based on noisy information, is considered. This task is a recurring problem in the theory of evolution strategies. Exact expressions for expected values of sums of products of concomitants of selected order statistics are derived. Then, using Edgeworth and Cornish-Fisher approximations, explicit results that depend on coefficients that can be determined numerically are obtained. While the results are exact only for normal populations, it is shown experimentally that including skewness and kurtosis in the calculations can yield greatly improved results for other distributions.     

A relation for the covariances of order statistics from n independent and non-identically distributed random variables

We derive a simple relation satisfied by the covariances of order statistics in the i.i.d. case and then generalize it to the case when the variables are independent and non-identically distributed. This relation could be employed successfully either to check the calculations or to reduce the amount of direct computations involved in evaluating the covariances of order statistics from an outlier model.     

当代生活与艺术之死:第二、第三和第一世界

当今所谓的艺术,主要是受20世纪七八十年代以来发展并在全球范围内扩散的美国式“艺术”观念所支配,而再也不受德语的“艺术”或法语的“美的艺术”体系所支配。自从现代主义诞生以来,艺术的历史使命的减弱或者消失已经成为事实,但从全球范围而言,“艺术的终结”这一论断仍有些夸大其词。因为在第一世界的艺术死亡之后(这里存在更多的是文化),第二和第三世界的艺术还生长着。艺术从根本上说还不是一个媒介事件和现象,而是一个同我们每个人相关的东西——不管它是不是商品。     

角式调节阀两相流模拟与结构改进

基于2003—2015年我国26个省、自治区的面板数据,重点考察了四万亿投资刺激计划背景下,各地区的财政货币政策对粮食价格波动的冲击效应及其差异。研究发现：中国粮食价格上涨除了受到生产成本因素驱动以外,还主要受到宽松的货币政策所引致的地方流动性过剩的影响,地方财政货币政策对粮食价格波动的冲击效应在四万亿投资实施前后存在明显的差异;四万亿刺激计划实施后,各地区积极的财政政策和宽松的货币政策才是新一轮粮食价格波动的主因,粮食类农产品因为自身的敏感和脆弱性,受到了财政货币政策引致的流动性泛滥所带来的最直接伤害;应注重财政货币政策的多重目标分解、梳理及协调配合,处理好“稳增长、控物价、调结构、惠民生、防风险”之间复杂多变的关系,寻求一个有效的“平衡点”。     

十月革命与中国共产党的初心构建

十月革命是影响世界历史进程的重大事件，中国共产党从来都把自己的事业看作是十月革命的继续。澄清唯心史观和历史虚无主义对十月革命的错误解读，对于补好理想信念的精神之钙具有重要的理论价值和现实意义。学习和借鉴十月革命的宝贵经验、坚持社会主义的前进方向、坚守共产主义的远大理想，共同构成了中国共产党初心的核心意蕴。     

To be or not to be valid in testing the significance of the slope in simple quantitative linear models with autocorrelated errors

In this article, the validity of procedures for testing the significance of the slope in quantitative linear models with one explanatory variable and first-order autoregressive [AR(1)] errors is analyzed in a Monte Carlo study conducted in the time domain. Two cases are considered for the regressor: fixed and trended versus random and AR(1). In addition to the classical t -test using the Ordinary Least Squares (OLS) estimator of the slope and its standard error, we consider seven t -tests with n-2\,\hbox{df} built on the Generalized Least Squares (GLS) estimator or an estimated GLS estimator, three variants of the classical t -test with different variances of the OLS estimator, two asymptotic tests built on the Maximum Likelihood (ML) estimator, the F -test for fixed effects based on the Restricted Maximum Likelihood (REML) estimator in the mixed-model approach, two t -tests with n - 2 df based on first differences (FD) and first-difference ratios (FDR), and four modified t -tests using various corrections of the number of degrees of freedom. The FDR t -test, the REML F -test and the modified t -test using Dutilleul's effective sample size are the most valid among the testing procedures that do not assume the complete knowledge of the covariance matrix of the errors. However, modified t -tests are not applicable and the FDR t -test suffers from a lack of power when the regressor is fixed and trended ( i.e. , FDR is the same as FD in this case when observations are equally spaced), whereas the REML algorithm fails to converge at small sample sizes. The classical t -test is valid when the regressor is fixed and trended and autocorrelation among errors is predominantly negative, and when the regressor is random and AR(1), like the errors, and autocorrelation is moderately negative or positive. We discuss the results graphically, in terms of the circularity condition defined in repeated measures ANOVA and of the effective sample size used in correlation analysis with autocorrelated sample data. An example with environmental data is presented.     

Tests for generalized exponential laws based on the empirical Mellin transform

Recently, many standard families of distributions have been generalized by exponentiating their cumulative distribution function (CDF). In this paper, test statistics are constructed based on CDF–transformed observations and the corresponding moments of arbitrary positive order. Simulation results for generalized exponential distributions show that the proposed test compares well with standard methods based on the empirical distribution function.