Exact moments of a ratio of two positive quadratic forms in normal variables

This paper derives an expression for rth raw moment of aratio of two quadratic forms in normal variables in terms of' a

convergent infinite series. Computational aspects of this formula are explored by considering a particular case.     

A perspective of composite sampling

Composite samples are formed by physically mixing samples. Usually, composite samples are used to reduce the overall cost associated with analytical procedures that must be performed on each sample, but they can also be used to protect the privacy of individuals.

Composite sampling can reduce the cost of identifying individual cases that have a certain trait, such as those with a rare disease or those exceeding pollution-level standards. Not much is lost by applying this method as long as the trait is relatively rare.

Composite sampling can reduce the cost of estimating the mean of some process. When samples are composited, the ability to estimate the variance is lost. In spite of this, the potential savings are so great that composite samples have been used.

Much of this paper deasl with the variance of estimators based on composite sampling when the porportions of hte original samples comprising the composite sample are actually random. Taking repeated samples and measurements on several composite samples complicates the prodcedure, but allows the estimation of between and within variation as well as measurement error.     

Density estimation using asymmetric kernels and Bayes bandwidths with censored data

We propose a modification to the regular kernel density estimation method that use asymmetric kernels to circumvent the spill over problem for densities with positive support. First a pivoting method is introduced for placement of the data relative to the kernel function. This yields a strongly consistent density estimator that integrates to one for each fixed bandwidth in contrast to most density estimators based on asymmetric kernels proposed in the literature. Then a data-driven Bayesian local bandwidth selection method is presented and lognormal, gamma, Weibull and inverse Gaussian kernels are discussed as useful special cases. Simulation results and a real-data example illustrate the advantages of the new methodology.     

Double‐mouthed discourse: Interpreting,framing, and participant roles1

In this article I examine multilingual displays in a Congolese Pentecostal church in Cape Town, South Africa. I focus on the simultaneous interpreting of the pastor's French sermon into English. I argue that the interpreting activity performed at church is used as a powerful interactional device to dramatize and shape the pastor's sermon. A close examination of participant roles shows that although these may appear to be predetermined by the interpretee‐interpreter format of the sermon, speaking roles are actually fluid and negotiated. I submit that an important role of the church interpreter is to convey the pastor's inspiration from the Holy Spirit and reach out to the potential audience absent from the here and now of the service. His high emotional engagement helps convey this inspiration prospectively to the audience and retroactively to the pastor himself.     

Teaching Sociology in Community College: Balancing Ideals with Institutional Constraints

Many professionals experience conflict between personal ideals about the meaning and importance of their work, and the structural limitations of the workplace. This conflict presents professionals with the challenge of how to hold true to their ideals within a non-supportive or even hostile environment. In this paper, I describe my experiences balancing my ideals about teaching, learning, and the purpose of a college education with the institutional constraints of a community college. There are three main sections in this paper. First is a discussion of the reasons I chose a career in community college teaching. The second section focuses on the institutional constraints I have encountered over the first 5 years of my career. In the third section, I explain how I have attempted to balance my ideals with the structural limitations of the college where I teach. Throughout the paper, I blend personal narrative with the relevant literature. In doing so, I intend to use my personal experience as a lens for discussing the challenges and possibilities that characterize community college teaching in general.     

Sources of occupational stress: An examination of British prison officers

Abstract

The purpose of this paper is to identify the major sources of occupational stress experienced by British prison officers and to examine their effects on overall job stress and job satisfaction. Eighty-one officers from HM Prison, Maidstone, took part in a questionnaire study, and three main findings emerged. First, lack of stiff and resources were ranked as the most likely sources of stress, and areas of the prison where confrontations with inmates were most likely to occur were ranked as the most stressful locations. Second, officers who reported the highest levels of job stress overall had the lowest job satisfaction and the greatest wish for more emphasis on control and security of inmates. Third, when the sources of stress were factor-analysed and used to predict overall job stress and job satisfaction, using multiple regression, the sìngle most important predictor of job stress was found to be the factor labelled 'confrontations with inmates' and, for dissatisfaction with the job, it was 'poor morale and resentments'. The paper discusses the theoretical implications of the findings.     

An F Approximation to the Distribution of a Linear Combination of Chi-squared Variables.

A three-parameter F approximation to the distribution of a positive linear combination of central chi-squared variables is described. It is about as easy to implement as the Satterthwaite-Welsh and Hall-Buckley-Eagleson approximations. Some reassuring properties of the F approximation are derived, and numerical results are presented. The numerical results indicate that the new approximation is superior to the Satterthwaite approximation and, for some purposes, better than the Hall-Buckley-Eagleson approximation. It is not quite as good as the Gamma-Weibull approximation due to Solomon and Stephens, but is easier to implement because iterative methods are not required.