On Sample Allocation in Multivariate Surveys

The problem of a sample allocation between strata in the case of multiparameter surveys is considered in this article. There are several multivariate sample allocation methods and, moreover, several criteria to deal with in such a case. A maximum coefficient of variation of estimators of the population mean of characters under study is taken as the optimality criterion. This article contains a study on a group of the methods that are easy to implement and do not need complex numerical computation; however, they all are approximate. Five such methods are presented and compared using a simulation study. Finally, it is shown which methods should be considered when designing a survey in which the multivariate sample allocation is to be involved.     

Relationship Between the Cox,Lehmann, Weibull,and Accelerated Lifetime Models

Cox and Oakes (1984 Cox , D. R. , Oakes , D. ( 1984 ). Analysis of Survival Data . New York : Chapman & Hall . [Google Scholar]) claimed that a model satisfies the accelerated lifetime (AL) model and the proportional hazards (PH) model iff it is Weibull. Doksum and Nabeya (1984 Doksum , K. A. , Nabeya , S. ( 1984 ). Estimation in proportional hazards and log-linear models . J. Statist. Plann. Infer. 9 : 297 – 303 .[Crossref], [Web of Science ®] , [Google Scholar]) constructed a family of analytic non Weibull survival functions that satisfies both the PH and AL models. We further study the relationship between the PH, AL, Lehmann, and Weibull models without the restriction of absolute continuity.     

Political extremism,group membership and personality traits: who accepts violence? / Extremismo político,pertenencia al grupo y rasgos de personalidad: ¿Quién acepta la violencia?

Abstract

Identity fusion theory proposed that fused individuals have a visceral feeling of oneness with the group and this leads them to engage in radical, violent pro-group behaviours. Other approaches to group extremism link acceptance of violence to right-wing authoritarianism (RWA) and social dominance orientation (SDO). We extended previous research on fusion in three ways. First, by exploring if identity fusion is a significant predictor of the willingness to fight for a group, when controlling for group identification, left-wing authoritarianism (LWA), RWA and SDO. Secondly, we controlled for a membership in a group known for radical action directed at out-groups, namely football hooligans. Finally, we added a second outcome variable, which is the acceptance of violent change of the current social system. The participants were self-described football hooligans (N = 24) and undergraduate students (N = 155). Regression analyses revealed that the strongest predictor of willingness to defend in-group was identity fusion, with RWA and group identification significant as well. RWA and LWA emerged as the strongest predictors of acceptance of violent change. The effect of group membership wasn’t significant.     

Sharp bounds on the expectations of L-statistics expressed in the Gini mean difference units

We describe a method of calculating sharp lower and upper bounds on the expectations of arbitrary, properly centered L-statistics expressed in the Gini mean difference units of the original i.i.d. observations. Precise values of bounds are derived for the single-order statistics, their differences, and some examples of L-estimators. We also present the families of discrete distributions which attain the bounds, possibly in the limit.     

Inequality in an OLG economy with heterogeneous cohorts and pension systems

We analyze the consumption and wealth inequality in an OLG model with mandatory pension systems. Our framework features within-cohort heterogeneity of endowments and heterogeneity of preferences. We allow for population aging and gradual decline in TFP growth. We show four main results. First, increasing longevity translates to substantial increases in aggregate consumption inequality and wealth inequality. Second, a pension system reform from a defined benefit to a defined contribution works to reinforce consumption inequality and reduce wealth inequality. Third, minimum pension benefits are able to partially counteract an increase in inequality introduced by the defined contribution system, at a fiscal cost. Fourth the minimum pension benefit guarantee mostly addresses the sources of inequality which stem from differentiated endowments rather than those which stem from heterogeneous preferences.     

Patterns of plant invasions at small spatial scale correspond with that at the whole country scale

Urban Ecosystems - Invasions were studied at different spatial scales, however these scales were rarely compared. The aim of this study is to compare the rate of expansion of eight alien plant...     

Electoral competition in 2-dimensional ideology space with unidimensional commitment

We study a model of electoral competition between two candidates with two orthogonal issues, where candidates are office motivated and committed to a particular position in one of the dimensions, while having the freedom to select (credibly) any position on the other dimension. We analyse two settings: one where both candidates are committed to the same dimension, and the other where each candidate is committed to a different dimension. We focus on characterisation and existence of pure strategy Nash equilibria when the core is empty. We show that if the distribution of voters’ ideal policies is continuously differentiable and has a bounded support, then an equilibrium exists if the candidates are differentiated enough. Our results for the case where the candidates have a common committed issue have implications for the literature on valence.     

计算机辅助机械设计中的成本分析

本文提出了通过机械设备生存期评估其成本的概念，描述了在机械设计过程中用计算机进行经济辅助分析，用参数化的方法进行面向机械设计的成本评估，同时讨论了基于零件特征的成本分析。