Bayesian Analysis of Multiple Hypothesis Testing with Applications to Microarray Experiments

Recently, the field of multiple hypothesis testing has experienced a great expansion, basically because of the new methods developed in the field of genomics. These new methods allow scientists to simultaneously process thousands of hypothesis tests. The frequentist approach to this problem is made by using different testing error measures that allow to control the Type I error rate at a certain desired level. Alternatively, in this article, a Bayesian hierarchical model based on mixture distributions and an empirical Bayes approach are proposed in order to produce a list of rejected hypotheses that will be declared significant and interesting for a more detailed posterior analysis. In particular, we develop a straightforward implementation of a Gibbs sampling scheme where all the conditional posterior distributions are explicit. The results are compared with the frequentist False Discovery Rate (FDR) methodology. Simulation examples show that our model improves the FDR procedure in the sense that it diminishes the percentage of false negatives keeping an acceptable percentage of false positives.     

Adolescents' contact with sexuality in mainstream media: A selection‐based perspective

Most work on adolescents’ contact with sexuality in mainstream media has been framed in terms of media effects upon the sexual self‐concepts, attitudes, and behaviors of youth, even when such causality cannot be inferred. Rarely examined are the sexual characteristics of adolescents that may predict contact with sexual media. Using Steele's (1999) Media Practice Model as a foundation, we reported on these associations for 2,184 Dutch adolescents. This study emphasized sex differences in the characteristics that predict such contact and the role of youths’ critical evaluations of information about sex in the media. Correlation and regression analyses revealed several sex differences in the characteristics related to sexual media contact, with individual characteristics accounting for more variance in females and critical evaluations accounting for more variance in males. This study underscores the need for more comprehensive, longitudinal studies of adolescents’ media consumption and its connections to sexual development in youth.     

Predicting treatment efficacy via quantitative magnetic resonance imaging: a Bayesian joint model

The prognosis for patients with high grade gliomas is poor, with a median survival of 1 year. Treatment efficacy assessment is typically unavailable until 5-6 months post diagnosis. Investigators hypothesize that quantitative magnetic resonance imaging can assess treatment efficacy 3 weeks after therapy starts, thereby allowing salvage treatments to begin earlier. The purpose of this work is to build a predictive model of treatment efficacy by using quantitative magnetic resonance imaging data and to assess its performance. The outcome is 1-year survival status. We propose a joint, two-stage Bayesian model. In stage I, we smooth the image data with a multivariate spatiotemporal pairwise difference prior. We propose four summary statistics that are functionals of posterior parameters from the first-stage model. In stage II, these statistics enter a generalized non-linear model as predictors of survival status. We use the probit link and a multivariate adaptive regression spline basis. Gibbs sampling and reversible jump Markov chain Monte Carlo methods are applied iteratively between the two stages to estimate the posterior distribution. Through both simulation studies and model performance comparisons we find that we can achieve higher overall correct classification rates by accounting for the spatiotemporal correlation in the images and by allowing for a more complex and flexible decision boundary provided by the generalized non-linear model.     

Beyond the Disciplinary Role of Governance: How Boards Add Value to Spanish Foundations

Due to the significant role of non‐profit organizations in the development of modern societies, these organizations must adjust their boardrooms. Since traditional theories of corporate governance appear to be limited in explaining the changing non‐profit world, we propose an extended model of governance that integrates the traditional arguments of agency theory with a cognitive dimension. Based on a sample of Spanish foundations, we present evidence on the effect of the board composition on foundations' organizational efficiency. We show that board size and independence do not have a definitive effect on the entity's efficiency. Instead, the knowledge diversity inside the boardroom and the active character of trustees have a positive influence on resource allocation. The cognitive dimension of the extended model of governance is critical to explaining how boards impact on organizational performance.     

An analytical management framework for new product development processes featuring uncertain iterations

This paper presents an analytical framework for effective management of projects with uncertain iterations. The framework is based upon: (1) the combination of two complementary techniques, one focused on improving iterative process architectures, the Design Structure Matrix, and one focused on predicting project performance, the Graphical Evaluation Review Technique; and (2) the introduction of an activity set-based criticality measure. The intent of the framework is to help project managers and researchers identify and evaluate alternative process architectures, in order to help them determine the alternative which best balances risk and other project performance parameters, as illustrated through an example application.     

Optimal unconditional critical regions for 2 2 2 multinomial trials

Analysing a 2 2 2 table is one of the most frequent problems in applied research (particularly in epidemiology). When the table arises from a 2 2 2 multinomial trial (or the case of double dichotomy), the appropriate test for independence is an unconditional one, like those of Barnard (1947), which, although they date from a long time ago, have not been developed (because of computational problems) until the last ten years. Among the different possible versions, the optimal (Martín Andrés & Tapia Garcia, 1999) is Barnard's original one, but the calculation time (even today) is excessive. This paper offers critical region tables for that version, which behave well compared to those of Shuster (1992). The tables are of particular use for researchers wishing to obtain significant results for very small sample sizes (N h 50).     

Women,Legal Aid and Social Inclusion

This article examines access to legal aid for women in light of the Australian government's social inclusion agenda. It is notable that the government's image of social citizenship does not include the ability to invoke and enforce legal rights, and that discourses of social exclusion have paid relatively little attention to gendered patterns of exclusion. The article reports on a study of applications for and refusals of legal aid for family law, domestic violence and anti‐discrimination matters by socially excluded women in Queensland. It demonstrates the variety of ways in which Legal Aid Queensland's grants process operated to further exclude and marginalise these women. It argues that effective access to legal aid is an important element of social inclusion, but that this goal cannot be achieved by reliance on the tools of New Public Management.     

Spin doctors in the spotlight: Effects of strategic press and publicity coverage on perceptions of political PR

News media often engage in strategy framing when covering politics, including strategic press and publicity coverage coined to express the focus on the media's role in the game of politics, as well as politicians’ calculated publicity and public relations efforts in relation to the media. This study examines the effect of strategic press and publicity coverage on perceptions of political PR once its practitioners and their publicity efforts have become the object of reporting. Drawing on data from two experiments (n = 863), we show how political PR professionals have themselves little to gain from becoming part of the story.     

An experimental study of thermal energy storage with phase change materials by design of experiments

Accurate theoretical modelling and simulation of thermal energy storage (TES) by means of phase change materials (PCM) is very complex and its results are not close enough to experimental values. This paper presents the empirical study of a thermal storage unit operating with a commercial PCM called RT25. The study is carried out by means of the statistical procedure, Design of Experiments. This methodology has rarely been used in the analysis of heat transfer problems. The present study has allowed us to investigate the phenomena involved and to design an actual system. We show the whole procedure followed in order to design the set-up, to run the experiments with a 2³ factorial design, to compare its results with a numerical simulation and to get the empirical model by regression. Its results have been used to design actual installations aimed at free-cooling or maintaining the temperature constant in rooms where thermal security is necessary.