Bayesian Alternatives to the F Test for Two Population Variances

Bayesian alternatives to the classical F test comparing two population variances are explored. Shoemaker (2003 Shoemaker , L. H. ( 2003 ). Fixing the F test for equal variances . The Amer. Statistician 57 : 105 – 114 .[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]) suggested two adjustments to the F test due to it being very sensitive to the normal assumption of the two populations. A simulation study is performed to compare the Bayesian alternatives to the F test and Shoemaker's adjusted F tests as well as to the Levene/Brown–Forsythe and the squared rank nonparametric tests. The Bayesian alternatives assume a normal parent distribution and non informative priors and the conjugate prior for the variances; in addition, an exponential power distribution is considered as the parent distribution with a non informative prior for the variances. The latter looks to be very promising provided that a suitable value of a parameter which measures the extent of non normality is chosen.     

A continuous-time Markov chain approach with the analytic likelihood in studies of behavioral changes

Abstract

We develop an analytic likelihood approach for a four-state CTMC by solving the backwards Kolmogorov differential equations, reducing this bias in transition rate estimates. A simulation study is performed to assess the performance of this new method and confirms that it achieves good coverage probabilities with low bias and standard errors. Finally, we analyzed data from Project SUCCESS to estimate the study each participant’s transitions among behavioral stage, consisting of risky drinking and possible ineffective using of contraception, which comprise the primary endpoint of risk of an alcohol-exposed pregnancy.     

KEEP foster-parent training intervention: model description and effectiveness

In this paper, we describe the development and history of the Keeping Foster Parents Trained and Supported (KEEP) foster-parent training intervention. KEEP intervention represents a modified version of the Multidimensional Treatment Foster Care intervention developed by interventionists at the Oregon Social Learning Center and is designed to provide training and support for children ages 5–11 in regular foster care. We also report on the initial findings from a programme of research focused on determining the effectiveness of the intervention. Thus far, the results indicate that the intervention is effective in reducing child behaviour problems and that the effects of the intervention are mediated through changes in parenting behaviour. There is also evidence that the KEEP foster-parent training intervention increases the chances of a positive change of placement (e.g. child reunited with biological parents) and mitigates the negative risk-enhancing effect of a history of multiple placements. We conclude with a discussion of unanswered questions and directions for future research.     

Genetic variants in ATP6 and ND3 mitochondrial genes are not associated with aggressive prostate cancer in Mexican–Mestizo men with overweight or obesity

Mitochondrial defects have been related to obesity and prostate cancer. We investigated if Mexican–Mestizo men presenting this type of cancer, exhibited somatic mutations of ATP6 and/or ND3.Body mass index (BMI) was determined; the degree of prostate cancer aggressiveness was demarcated by the Gleason score. DNA from tumor tissue and from blood leukocytes was amplified by the polymerase chain reaction and ATP6 and ND3 were sequenced. We included 77 men: 20 had normal BMI, 38 were overweight and 19 had obesity; ages ranged from 52 to 83. After sequencing ATP6 and ND3, from DNA obtained from leukocytes and tumor tissue, we did not find any somatic mutations. All changes observed, in both genes, were polymorphisms. In ATP6 we identified, in six patients, two non-synonymous nucleotide changes and in ND3 we observed that twelve patients presented non-synonymous polymorphisms. To our knowledge, this constitutes the first report where the complete sequences of the ATP6 and ND3 have been analyzed in Mexican–Mestizo men with prostate cancer and diverse BMI. Our results differ with those reported in Caucasian populations, possibly due to ethnic differences.     

Are Gambling Related Cognitions in Adolescence Multidimensional?: Factor Structure of the Gambling Related Cognitions Scale

The present study examined the factor structure of the Gambling Related Cognitions Scale (GRCS); (Raylu and Oei in Addiction 99:757–769, 2004) in a large sample of adolescents (N = 1,490) between the ages of 16 and 18 years (630 males, 860 females) attending several high schools in central Ontario. Problem gambling was measured using the DSM-IV-J (Fisher in J Gambl Stud 8:263–285, 1992). A 5-factor GRCS model was found to have the best fit to the data, and gambling-related cognitions were found to be powerful predictors of disordered gambling among adolescents. However, strong associations among GRCS subscales, as well as the small amount of variance in problem gambling accounted for by specific GRCS subscales, call into question the multidimensionality of the GRCS when used with adolescents.     

Emergency departments and street-involved youth: factors influencing utilization

Homeless youth often have untreated health problems and experience barriers to care. Existing evidence suggests that homeless youth use emergency departments (EDs) more frequently than other youth. We hypothesized that street youth with access to primary care services would be less likely to utilize EDs for health care. Data were drawn from a study of housing security and changes to it over time among 150 youth (16–20 years) recruited from service agencies for street-involved youth. Our findings show that those with access to primary care were actually more likely to use the ED, suggesting that access may encourage further engagement with the health care system. Findings support the need to better understand why access to primary care increases ED use and what could be done to change this pattern.     

Macroergonomic aspects in the design of development programs in IDCs

This paper revisits three reports on ergonomic aspects of development initiatives taking place in Industrially Developing Countries (IDCs). These include a macro-ergonomics intervention in a habitation community in Cape Verde (aimed at designing solutions contributing to sustainable development), the evolution of poultry growers' control strategies as an integrative broiler operation is introduced in Mozambique, and a set of macro-ergonomic considerations related to the Agro Forestry Village Project in Mozambique. The paper seeks to set the reviewed development endeavors against the backdrop of the goals of ergonomics interventions. This reflection may inform development agents in future processes of design and implementation of integrated community and work systems transformation.     

Urban ergonomics: an ongoing study of city signs and maps

The purpose of this study is to assess whether the existing signals in three European cities were developed according usability principles and ergonomic aspects for the citizen. City maps and signals will be tested using efficiency, effectiveness and user's satisfaction criteria. Among the urban areas are the center of Paris-FR, assumed to be well signalized, the historical center of Guimar?es-PT and Chorweiler, Cologne-DE, a residential neighborhood of modern urbanism characterized by the extensive use of vegetation, the landscape homogeneity, and, consequently, by the difficult navigation.     

Just Another American Story? The First Black First Family

Analyses of racial equality and gender equity remain muted within contemporary U.S. public policy debates. This context mandates a search for a new language to address social inequalities generally, and racial inequalities in particular. In this regard, the construct of family may be especially useful in that family rhetoric is the symbolic carrier of multiple, often contradictory stories about race, gender, class, sexuality and citizenship. Moreover, because family structures are vital institutional carriers for economic transformations of the new global economy, public policies can be made comprehensible via the rhetoric of family. Using the centrality of family narratives in Barack Obama??s campaign and subsequent Presidency as a site for exploring changing conceptions of race, gender, economic security and American national identity, this essay explores how the symbolic and structural dimensions of family have been an important part of the American national story.