Comparative performance of tests of normality in detecting mixtures of parallel regression lines

This paper addresses the problem of detecting a mixture of parallel regression lines when information about group member¬ship of individual cases is not given. The problem is approached as a missing variable problem, with the missing variables being the dummy variables that code for groups. If a mixture of par¬allel regression lines with normally distributed error terms is present, a simple regression model without dummy variables will produce residuals that follow approximately a mixed normal dis¬tribution. In a simulation studyr several goodness-of-fit tests of normality were used to test the residuals obtained from mis-specified models that excluded dummy variables, Factors varied in the simulation included the number and the separation of the parallel lines and the sample size, The goodness-of-fit test based on the sample kurtosis (82) was overall most powerful in detecting mixtures of parallel regression lines, Applications are discussed.     

How Fair Is Safe Enough? The Cultural Approach to Societal Technology Choice1

This paper consists of an argument and a pilot study. First is a general, perhaps philosophical, argument against the National Academy's viewpoint⁽¹⁾ that dealing with risk is a two-stage process consisting of (a) assessment of facts, and (b) evaluation of facts in sociopolitical context. We argue that societal risk intrinsically revolves around social relations as much as around evaluations of probability. Second, we outline one particular approach to analyzing societal risk management styles. We call this the fairness hypothesis. Rather than focusing on probabilities and magnitudes of undesired events, this approach emphasizes societal preferences for principles of achieving consent to a technology, distributing liabilities, and investing trust in institutions. Conflict rather than probability is the chief focus of this approach to societal risk management. This view is illustrated by a recent empirical pilot study that explored the fairness hypothesis in the context of new nuclear technologies.     

Mixed Messages in Risk Communication

The exchange of risk information between risk managers and affected parties is frequently hampered by differences in the understanding or interpretation of many words and phrases. Much of the terminology used by risk practitioners may have different "technical" and "colloquial" meanings, resulting in "mixed messages" in risk communication. Several words and concepts commonly used in risk management that may be resulting in these "mixed messages" are discussed. These include primary underlying concepts, such as the various meanings of the word "risk" itself, as well as the perplexity of the notions of "safety vs. zero risk" and "probability". The potential "mixed messages" of the derived concepts of "significant vs. nonsignificant", "negative vs. positive results", "conservative assumptions", "population vs. individual risk", "relative vs. absolute risk", and "association vs. causation" are shown to range from mild confusion to the completely opposite interpretation of these words and expressions. Suggested strategies for recognizing and mitigating the use of words and phrases which may create unnecessary confusion are presented.     

A new test for the presence of a normal mixture distribution based on the posterior Bayes factor

We present a new test for the presence of a normal mixture distribution, based on the posterior Bayes factor of Aitkin (1991). The new test has slightly lower power than the likelihood ratio test. It does not require the computation of the MLEs of the parameters or a search for multiple maxima, but requires computations based on classification likelihood assignments of observations to mixture components.     

The Exchange of Aesthetics: Women's Work and ‘The Gift’

Drawing on empirical research data on the work of flight attendants, this paper will explore Marcel Mauss's theory of ‘gift’ exchange relations, with particular reference to his concern with the ‘exchange of aesthetics’ (Mauss 1954), as an analytical model which may contribute to our understanding of ‘women's work’ in contemporary Western societies, of which, we shall argue, the work of female flight attendants is a notable example. It will begin by locating the authors' analytical and theoretical concerns with ‘women's work’ within the context of recent empirical research. It will then go on to outline briefly a Maussian model of exchange relations and to identify the potential utility of this analytical model for the study of women's work. This paper then goes on to offer an analytical account of empirical research into the work of flight attendants and to analyse the ways in which airline service provision constitutes a critical case study of women's work, certain elements of which involve a form of ‘gift’ exchange relations which operate, not as an alternative to, but inside — and in the interests of — commodity exchange relations. Finally, in the light of recent feminist work, this paper will conclude by suggesting the wider implications of this analytical model for the study of gender and work.     

《管子》论说文的论证方法及其语言特征

论说文是《管子》中的主要文体。这些文章立意明确，主旨集中，论辩严密，论证方法灵活多样，达到了较高的水平，可以说是集先秦论说文体之大成，它在中国文体发展史上具有重要的地位。     

Life spans of Library Journal's “Best Magazines of the Year”

Abstract

An annual column published in Library Journal reviews the best new magazines of the previous year. Despite being chosen for their quality, a portion of them fail at a rate described in this study. Reasons for failure and characteristics of ceased titles are described, as are difficulties in determining end dates from records in OCLC, Ulrich's, and the Serials Directory. This study reveals that OCLC records had not been closed for 30 percent of the ceased periodicals. A list of successful and widely held “best of” magazines is appended.     

子女受教育状况在农户非农 外出务工决策中的作用

文章旨在分析农户在非农外出务工决策过程中受子女受教育状况的影响程度。文章利用甘肃基础教育的调查数据，比较了不同类型农户的家庭特征和地区特征，并采用概率模型实证分析了子女受教育状况对农村地区非农外出务工决策的作用。研究结果表明，农户外出务工决策明显受到子女受教育状况的抑制影响，家庭中学龄前儿童、小学生和高中生人数每增加1人，家庭外出务工的概率将分别降低17．89％、3．93％、6．90％。这在一定程度上验证了代际因素在农户家庭决策中的重要作用。