A Bayesian mixture model for differential gene expression

Summary.  We propose model-based inference for differential gene expression, using a nonparametric Bayesian probability model for the distribution of gene intensities under various conditions. The probability model is a mixture of normal distributions. The resulting inference is similar to a popular empirical Bayes approach that is used for the same inference problem. The use of fully model-based inference mitigates some of the necessary limitations of the empirical Bayes method. We argue that inference is no more difficult than posterior simulation in traditional nonparametric mixture-of-normal models. The approach proposed is motivated by a microarray experiment that was carried out to identify genes that are differentially expressed between normal tissue and colon cancer tissue samples. Additionally, we carried out a small simulation study to verify the methods proposed. In the motivating case-studies we show how the nonparametric Bayes approach facilitates the evaluation of posterior expected false discovery rates. We also show how inference can proceed even in the absence of a null sample of known non-differentially expressed scores. This highlights the difference from alternative empirical Bayes approaches that are based on plug-in estimates.     

Disrupted Bodies: Experiencing the Newly Limited Body in Stroke

This article explores the intersection of recovery and bodily practices among stroke survivors. Drawing on the extensive literature on the socially constructed body in general, on chronic illness, and on interactionist thought, we explore bodily experience as a mechanism that informs stroke survivors' understanding and practices of everyday life in recovery. We ask a central question: what practical mechanisms does the survivor employ to provide meaning to her or his newly disrupted body? Data gathered from in‐depth interviews with fifty‐one discharged stroke survivors show that they use three specific technologies of bodily management and meaning‐making. These are managing the body within a mind‐body dualism, testing the body in its everyday practices, and orienting to the body as a biographically informed phenomenon.     

Two-Player Asymmetric Contests with Ratio-Form Contest Success Functions

I examine players' equilibrium effort levels in two-player asymmetric contests with ratio-form contest success functions. I first characterize the Nash equilibrium of the simultaneous-move game. I show that the equilibrium effort ratio is equal to the valuation ratio, and that the prize dissipation ratios for the players are the same. I also show that the prize dissipation ratio for each player is less than or equal to the minimum of the players' probabilities of winning at the Nash equilibrium and thus never exceeds a half. Then I examine how the equilibrium effort ratio, the prize dissipation ratios, and the players' equilibrium effort levels respond when the players' valuations for the prize or their abilities change.     

Identifying units in interaction: Reactive tokens in Korean and English conversations

Reactive tokens are conversational resources by which a listener co‐constructs a speaker's turn at talk. The resources that are available include the forms of the reactive tokens themselves, their duration, and their placement by the listener in the current speaker's turn. The present paper is a contrastive study of the use of these resources by Americans in English, and by Koreans in their native language and in English, and in it we show the ecological relationship between the resources that a language provides and their use in constructing active listenership. Although previous research on English has found listeners use reactive tokens to pass up the opportunity for a full turn at talk, we show that, in Korean, reactive tokens are often elicited by the current speaker and the listener is obligated to provide them. We present evidence that Korean bilinguals transfer some conversational resources from their native language when they take part in conversation in English.     

INDEPENDENCE DISTRIBUTION-PRESERVING NONNEGATIVE-DEFINITE COVARIANCE STRUCTURES FOR THE SAMPLE VARIANCE

This paper explicitly characterizes the general nonnegative-definite covariance structure for a multivariate normal random vector such that the univariate sample variance is distributed exactly as if the sample observations are normal independent and identically distributed (i.i.d.). This work extends the results of Baldessari (1965) and Stadje (1984) who have characterized the general positive-definite covariance matrix such that the univariate sample variance is distributed exactly as if the sample observations are normal i.i.d.     

Work‐to‐Society Spillover?

Nonprofit employees can make ideal volunteers for other organizations in the sector, and understanding their participation in volunteering is a timely task. Based on “spillover theory,” this study tests how nonprofit employees’ experience on the job may carry over into the nonwork arena. The study focuses on how nonprofit employees’ satisfaction with the job and perception of the organization's mission achievement relate to their volunteering, controlling for the generally higher levels of prosocial motivation found in the sector. The findings suggest that the consequences of job satisfaction for this group extend beyond the workplace, contributing to societal benefits.     

Utilizing Digital Advocacy in Community Organizing: Lessons Learned from Organizing in Virtual Spaces to Promote Worker Rights and Economic Justice

This article discusses the usefulness and challenges associated with utilizing social media technologies in the context of community organizing practice, often referred to as digital advocacy. We ground the analysis of digital advocacy in the context of a recent organizing effort undertaken by social work academics, grass roots organizers, and allies to support the boycott of Hyatt Hotels in San Antonio, Texas, by marginalized hotel workers and labor unions through advocating that the Society for Social Work Research relocate their 2014 conference from the Grand Hyatt, San Antonio, and to work toward better conference planning procedures in the future.     

Stabilization,birth waves,and the surge in the elderly*

Substantial regularities characterize the transition to stability that follows a shift from one set of vital rates to another. The new vital, rates interact with the population's initial age composition and generate birth waves whose amplitude and attenuation depend on the ratio of ultimate to initial growth and on the new pattern of stable net maternity. A greater change in growth and a later stable net maternity pattern produce larger fluctuations in the number of births. Stabilization begins at the youngest ages and proceeds upward. Sixty years after the shift, the birth waves have largely disappeared and the proportion under age 15 approximates the stable level implied by the new rates. Those patterns are manifest in the stabilization of both observed and Coale‐Demeny model stable populations.

When fertility falls, the new stable population has a larger fraction at all ages above (approximately) 30, with greater changes characterizing the extremes of life. Fifteen years after the fall, there is a trough in the number at ages 0–14. Sixty years after the fall, when the largest pre‐decline cohort is age 60–74 and the smallest post‐decline cohort is age 45–59, there is a surge in the relative size of the elderly population. Thus after two generations, the birth waves produced by a rapid decline in fertility accentuate the effects of population aging.     

A semi‐Markovian approach to using event history data in multiregional demography

As a first step towards infusing event‐history analysis into multiregional demography, this paper introduces a semi‐Markovian framework and outlines its salient features as differentiated from a pure Markovian framework. Specifically, what differentiates the former from the latter is an explicit consideration of duration‐dependence in migrating from one region to another. This duration‐dependence is one of the complexities involved in using event‐history data in multiregional demography. The use of event‐history data lends itself easily to defining basic probabilities involved in a semi‐Markovian framework directly on sample paths of individuals. The underlying concepts of a semi‐Markov process in the special case of time‐homogeneity or age‐independence of transition probabilities are given in a coherent and concise form. Illustrations of empirical applications to the event‐history data on migration as provided by the Korean National Migration Survey conducted in 1983, and of distinct features of the semi‐Markovian analysis through a parametrization of the basic probabilities are also given in this paper.