Commodity prices and the world distribution of income

Some advocates of a new international economic order recommend raising prices of commodities exported by developing countries as a means of reducing the inequality of world income distribution. A simulation model using commodity trade data and income distribution data for 68 industrial and developing countries examines this policy alternative. Initial data compilation reveals that internal inequality is as important as international: The world income share of the poorest 40% of people would be twice as high in the absence of intracountry inequality. Calculations using actual price experience in the “great inflation” of 1972–1975 show that despite the large relative price changes for some commodities (especially oil), these changes left the world size distribution of income virtually unchanged. Separate policy simulations show that even a quadrupling of the price of ali “equalizing” commodities (those mainly exported by LDCs) would leave the size distribution of world income practically unaltered (even under optimistic assumptions about intracountry distributional incidence), although some individual LDCs would gain. Increasing commodity prices therefore appears to be an ineffective means of increasing international equity, quite apart from questions about the feasibility of cartels or commodity agreements.     

Semiparametric median residual life model and inference

For randomly censored data, the authors propose a general class of semiparametric median residual life models. They incorporate covariates in a generalized linear form while leaving the baseline median residual life function completely unspecified. Despite the non‐identifiability of the survival function for a given median residual life function, a simple and natural procedure is proposed to estimate the regression parameters and the baseline median residual life function. The authors derive the asymptotic properties for the estimators, and demonstrate the numerical performance of the proposed method through simulation studies. The median residual life model can be easily generalized to model other quantiles, and the estimation method can also be applied to the mean residual life model. The Canadian Journal of Statistics 38: 665–679; 2010 © 2010 Statistical Society of Canada     

负二项分布的推广

本文主要是在二项分布,多项分布,负二项分布的基础上,把负二项分布进一步推广,给出负N项分布的定义,推导出它的概率分布,并计算出其数学期望和方差.     

On the incidence–prevalence relation and length‐biased sampling

For many diseases, logistic constraints render large incidence studies difficult to carry out. This becomes a drawback, particularly when a new study is needed each time the incidence rate is investigated in a new population. By carrying out a prevalent cohort study with follow‐up it is possible to estimate the incidence rate if it is constant. The authors derive the maximum likelihood estimator (MLE) of the overall incidence rate, λ, as well as age‐specific incidence rates, by exploiting the epidemiologic relationship, (prevalence odds) = (incidence rate) × (mean duration) (P/[1 ? P] = λ × µ). The authors establish the asymptotic distributions of the MLEs and provide approximate confidence intervals for the parameters. Moreover, the MLE of λ is asymptotically most efficient and is the natural estimator obtained by substituting the marginal maximum likelihood estimators for P and µ into P/[1 ? P] = λ × µ. Following‐up the subjects allows the authors to develop these widely applicable procedures. The authors apply their methods to data collected as part of the Canadian Study of Health and Ageing to estimate the incidence rate of dementia amongst elderly Canadians. The Canadian Journal of Statistics © 2009 Statistical Society of Canada     

The macroeconomics of fertility in small open economies: A test of the Becker-Barro model for The Netherlands and New Zealand

Becker and Barro (1988) formulated a theoretical model which identified a range of macroeconomic variables which can temporarily or permanently affect fertility in small open economies. This article tests the Becker-Barro model with relevant data which covers most of the 20th century for two small open economies, namely The Netherlands and New Zealand. The results show that government subsidies for having children have a strong positive effect on fertility, while the provision of public pensions has a strong negative effect. The degree of intergenerational altruism appears to have been declining. Moreover, there is only weak support for the hypothesis that real interest rates positively influence fertility. Received: 2 March 1998/Accepted: 1 September 1999     

中共发展华中战略与皖南事变

自从1938年底中共中央做出发展华中的决策后,皖南和江南的战略地位开始下降,华中逐渐成为新四军发展的重要战略支点。为此,皖南新四军必须北移以作支援。而国民党政府以中央政府的身份迭次发出命令,必欲将中共军队驱逐出华中。国共在华中,尤其是苏北的冲突日渐激烈。《中央提示案》和“皓电”发出后,中共中央并未屈服于国民党的压力,相反加紧发展华中,并要皖南方面做好北移准备,试图以此让步缓解双方矛盾。但就在中共试图缓和国共关系之时,苏北的曹甸战斗却使双方更形紧张,也使皖南新四军直接北渡长江成为其唯一选择。就在皖南新四军北移途中,皖南事变发生了。     

AN1N2定中结构的类型分析

从表层来看,AN1N2是一个简单的三元素定中结构,只有两种分类的可能性(A-N1N2和AN1-N2).本文深入这一结构的内部,挖掘其深厚、丰富的语义内涵,充分关注语义和句法的互动关系,运用句法变换、成分删除等语法分析手段,分解出一系列涵盖在表层线性形式下AN1N2的聚合类,构建出ANlN2结构的下位分类系统,并对其对立和生成机制进行了解释.     

有关PCR制备siRNA表达框的研究及其应用

RNA干扰(RNAi)是指具有同源性的双链RNA导致靶mRNA发生序列特异性降解的现象。随着对RNAi分子机制研究的深入,该技术在哺乳动物的实现策略不断改进,最初是以化学方法合成小干扰RNA(siRNA),目前则包括化学合成法、体外转录法、RNaseⅢ家族体外消化法、表达载体法和PCR制备siRNA表达框法等。本文将对PCR制备siRNA表达框法的原理以及具体过程以及其特点还有运用作一详细综述。     

从词类范畴化理论看“副词＋名词”结构

不少学者对汉语中所谓的“副词＋名词”结构从各方面进行了研究，但是无一质疑该结构中心词的词类判断。对刘正光等人提出的观点提出质疑，认为：汉语词类的判断不能依赖于直觉或语义，而应在使用大型汉语语料库的基础上，依据词的语法功能来确定；词类范畴化是动态的过程，包括去范畴化和再范畴化，再范畴化是去范畴化的最终结果；对于“副词＋名词”结构中发生的词类去范畴化，语法转喻是其内在运作机制。     

Characterizations of geometric distribution and discrete IFR (DFR) distributions using order statistics

Let X be a discrete random variable the set of possible values (finite or infinite) of which can be arranged as an increasing sequence of real numbers a₁<a₂<a₃<…. In particular, a_i could be equal to i for all i. Let X_1n≦X_2n≦?≦X_nn denote the order statistics in a random sample of size n drawn from the distribution of X, where n is a fixed integer ≧2. Then, we show that for some arbitrary fixed k(2≦k≦n), independence of the event {X_kn=X_1n} and X_1n is equivalent to X being either degenerate or geometric. We also show that the montonicity in i of P{X_kn = X_1n | X_1n = a_i} is equivalent to X having the IFR (DFR) property. Let a_i = i and $\text{G(i) = P(X≧i), i = 1, 2, …}$. We prove that the independence of {X_2n ? X_1n ∈B} and X_1n for all i is equivalent to X being geometric, where B = {m} (B = {m,m+1,…}), provided G(i) = q^i?1, 1≦i≦m+2 (1≦i≦m+1), where 0<q<1.