A cross-cultural test of the situational bias hypothesis : The israeli scene

The major aim of this study was to test the commonly held assumption, within the Israeli educational context, that the relatively poor mean performance of disadvantaged students on conventional ability tests is due, in part, to extraneous situational factors, systematically disadvantageous to their test performance. To that end, two controlled field experiments were conducted on independent samples of N = 288 and N = 48 elementary school pupils, respectively. The first experiment centered on the interaction between sociocultural group characteristics and each of two situational factors, namely, test atmosphere and examiner status, in affecting ability test performance. The second experiment explored the effects of test atmosphere per se on the nonverbal ability test scores of disadvantaged pupils. On the whole, this research provides evidence inconsistent with the situational bias hypothesis and does not support the assumption that disadvantaged children's ability test scores can be substantially improved by manipulating test atmosphere conditions. In view of the evidence showing that situational variables do not significantly bias testing results in favor of one group over another, it follows that current educational evaluation policies in Israel, relying heavily on the standardized ability tests results of disadvantaged groups, need not be changed.     

FEDERAL TRANSFER PAYMENTS IN AMERICA: VETERANS' PENSIONS AND THE RISE OF SOCIAL SECURITY

This paper examines the determinants of the adoption of the veterans' pension program and how it served as a prototype for the creation and administration of the federal welfare system in the United States. We provide statistical evidence in the form of an analysis of votes in the House of Representatives that state-based special interests which had supported the ongoing liberalization of the veterans' pension program provided significant support for the adoption of the Social Security Act of 1935. There is clear evidence the social security system was not adopted as a simple extension of state old-age pension programs.     

Robust estimation for linear regression with asymmetric errors

The authors propose a new class of robust estimators for the parameters of a regression model in which the distribution of the error terms belongs to a class of exponential families including the log‐gamma distribution. These estimates, which are a natural extension of the MM‐estimates for ordinary regression, may combine simultaneously high asymptotic efficiency and a high breakdown point. The authors prove the consistency and derive the asymptotic normal distribution of these estimates. A Monte Carlo study allows them to assess the efficiency and robustness of these estimates for finite samples.     

关于党与人大在国家中地位的理性分析

党政关系是政治体制改革的中心环节,党政关系之所以难分难解的根本原因之一就在于党部分地承担起本应由人大来履行的职责,所以说党政关系最重要的就是党与人大的关系。只有正确处理党与人大的关系才能从根本上克服“党政不分”的弊端。然而,正确处理党与人大的关系却是一个复杂且难度很大的问题。对党与人大在国家中地位的分析可以帮助我们更好地处理两者的关系。     

A galling aphid with extra life-cycle complexity: Population ecology and evolutionary considerations

Summary In most gall-forming aphids, only the fundatrix is able to induce a gall on the host plant. InSmynthurodes betae Westw. (and a few other species), F₂ descendants emerge from the mother gall and induce their own, morphologically different galls. This constitutes an added complexity to the already very complex life cycle of gall-forming aphids. We investigated the ecology ofS. betae on marked trees and shoots at four sites in Israel. Gall initiation, gall distribution and density, and temporal changes in clone size within the galls were investigated during two consecutive years. We discuss the possibility that the two-gall life cycle evolved from the typical one-gall system of most gall aphids, and the possible selective advantage of this added complexity in the life-history strategy of gall aphids. Although the total reproductive output ofS. betae is not higher than in related species with a single gall per life cycle, there seems to be an advantage in the subdivision of each aphid clone into several galls, thus reducing the risk of the accidental extinction of the clone (genotype) by environmental factors, including parasites and predators.     

Stochastic comparison of processes generated by random interruptions of monotone functions and related results

Many stochastic processes considered in applied probability models, and, in particular, in reliability theory, are processes of the following form: Shocks occur according to some point process, and each shock causes the process to have a random jump. Between shocks the process increases or decreases in some deterministic fashion. In this paper we study processes for which the rate of increase or decrease between shocks depends only on the height of the process. For such processes we find conditions under which the processes can be stochastically compared. We also study hybrid processes in which periods of increase and periods of decrease alternate. A further result yields a stochastic comparison of processes that start with a random jump, rather than processes in which there is at the beginning some random delay time before the first jump.Supported by NSF Grant DMS 9303891.     

Why Risk Analysis is Difficult,and Some Thoughts on How to Proceed

Risk analysis is challenged in three ways by uncertainty. Our understanding of the world and its uncertainties is evolving; indeterminism is an inherent part of the open universe in which we live; and learning from experience involves untestable assumptions. We discuss several concepts of robustness as tools for responding to these epistemological challenges. The use of models is justified, even though they are known to err. A concept of robustness is illustrated in choosing between a conventional technology and an innovative, promising, but more uncertain technology. We explain that nonprobabilistic robust decisions are sometimes good probabilistic bets. Info‐gap and worst‐case concepts of robustness are compared. Finally, we examine the exploitation of favorable but uncertain opportunities and its relation to robust decision making.     

几种电路分析方法适用范围的讨论

通过实例讨论了支路电流法、网孔分析法、节点电压法、叠加原理和戴维南定理的适用性 ,最后对电路分析时不同电路如何选用合适方法给出了一个参考性选择     

Peers,proactivity, and problem-solving: A multilevel study of team impacts on stress appraisals of problem-solving demands

ABSTRACT

To date, there is a paucity of research on team-level impacts on the individual stress appraisal process despite the recognised role of teams for solving problems. Applying a multilevel approach, this study investigates the cross-level impact of team problem prevention behaviours on employee stress appraisals of problem-solving demands. It was hypothesised that team problem prevention would moderate the individual-level relationship between problem-solving demands and stress appraisals. Data were collected from 43 work teams comprised of 192 team members including all team leaders who also provided evaluations of their team’s problem prevention behaviour. Results supported the hypothesised cross-level moderating effects on challenge appraisal, but not threat appraisal. As one of the first studies to demonstrate that stress appraisals are impacted by the group, not just by individual factors, the results support a multilevel conceptualisation of stress appraisals. The findings also highlight implications for practice, broadening the scope of possibilities for stress management interventions to utilise team-level strategies such as leadership development programmes and/or team building initiatives.