A Bayesian Analysis for Accelerated Lifetime Tests Under an Exponential Power Law Model with Threshold Stress

In this paper, we present a Bayesian methodology for modelling accelerated lifetime tests under a stress response relationship with a threshold stress. Both Laplace and MCMC methods are considered. The methodology is described in detail for the case when an exponential distribution is assumed to express the behaviour of lifetimes, and a power law model with a threshold stress is assumed as the stress response relationship. We assume vague but proper priors for the parameters of interest. The methodology is illustrated by a accelerated failure test on an electrical insulation film.     

Sense of Belonging in School as a Protective Factor Against Drug Abuse Among Native American Urban Adolescents

This article presents the results of a study conducted with 243 Native American students who were part of a multi-ethnic sample of adolescents attending middle school in a large urban center in the Southwest region of the United States. Native adolescents who felt a stronger sense of belonging in their school were found to report a lower lifetime use of alcohol and cigarettes, lower cigarette and marijuana use in the previous month, lower frequency of current use of these substances, fewer substances ever used, and a later age of initiation into drug use than other Native students. Research implications are discussed in relationship to school environment, culturally-grounded prevention curricula, and school social work practice.     

How do industry and country impact firm performance? A national and supranational analysis

We contribute to the literature of the country, industry and firm effects on performance by developing an autoregressive cross-classified mixed-effect linear model that examines heterogeneity in the profitability of corporations in emerging and developed economies, as well as corporations located in different supranational regions. To this purpose, we simultaneously decompose abnormal returns into permanent and transitory components at the firm, industry, country and industry–country levels. We find that firms in emerging countries have significantly higher rates of performance persistence and different sources of persistence compared to firms located in developed countries. These differences are also evident between different supranational regions and countries at different levels of institutional development.

     

Diagnostics in elliptical regression models with stochastic restrictions applied to econometrics

We propose an influence diagnostic methodology for linear regression models with stochastic restrictions and errors following elliptically contoured distributions. We study how a perturbation may impact on the mixed estimation procedure of parameters in the model. Normal curvatures and slopes for assessing influence under usual schemes are derived, including perturbations of case-weight, response variable, and explanatory variable. Simulations are conducted to evaluate the performance of the proposed methodology. An example with real-world economy data is presented as an illustration.     

Assessing the relevance of higher education courses

The establishment of the European Higher Education Area has involved specifying lists of professional competencies that programs are expected to develop, and with this the need for procedures to measure how every course within a higher education program is aligned with the program's competencies. We propose an instrument for characterizing this alignment, a process that we call assessing the relevance of a course. Using information from the course syllabus (objectives, contents and assessment scheme), our instrument produces indicators for characterizing the syllabus in terms of a competence list and for assessing its coherence. Because assessment involves quality, the results obtained can also be used to revise and improve the course syllabus. We illustrate this process with an example of a methods course from a mathematics teacher education program at a Spanish university.     

Urban ecosystem Services in Latin America: mismatch between global concepts and regional realities?

Urban Ecosystems - Latin America and the Caribbean (LAC) is one of the most urbanized and biologically diverse regions in the world but is often characterized by weak environmental governance and...     

Modeling stereotypes and negative self‐stereotypes as a function of interactions among groups with power asymmetries

Stereotypes is one of the most researched topics in social psychology. Within this context, negative self‐stereotypes pose a particular challenge for theories. In the current work, we propose a model that suggests that negative self‐stereotypes can theoretically be accounted for by the need to communicate in a social system made up by groups with unequal power. Because our theory is dynamic, probabilistic, and interactionist, we use a computational simulation technique to show that the proposed model is able to reproduce the phenomenon of interest, to provide novel accounts of related phenomena, and to suggest novel empirical predictions. We describe our computational model, our variables' dynamic behavior and interactions, and link our analyses to the literature on stereotypes and self‐stereotypes, the stability of stereotypes (in particular, gender and racial stereotypes), the effects of power asymmetries, and the effects of intergroup contact.