Power Law Selection Model for Repairable Systems

A repairable system, under minimal repair, is usually modeled according to a Non-Homogeneous Poisson Process (NHPP) assuming a Power Law intensity function. A traditional approach considers iid NHPPs in order to conduct a statistical analysis based on a sample of systems. However, systems might be heterogeneous due to unmeasured variables such as age, suppliers, and so on. In order to verify this assumption a frequentist approach is proposed in this article. Some possible model scenarios considering different systems heterogeneity are compared using likelihood ratio tests and information criteria. Real data sets illustrate the proposed methodology.     

Application of Correspondence Analysis in the Assessment of Mine Tailings Dam Breakage Risk in the Mediterranean Region

A new statistical approach for preliminary risk evaluation of breakage in tailings dam is presented and illustrated by a case study regarding the Mediterranean region. The objective of the proposed method is to establish an empirical scale of risk, from which guidelines for prioritizing the collection of further specific information can be derived. The method relies on a historical database containing, in essence, two sets of qualitative data: the first set concerns the variables that are observable before the disaster (e.g., type and size of the dam, its location, and state of activity), and the second refers to the consequences of the disaster (e.g., failure type, sludge characteristics, fatalities categorization, and downstream range of damage). Based on a modified form of correspondence analysis, where the second set of attributes are projected as "supplementary variables" onto the axes provided by the eigenvalue decomposition of the matrix referring to the first set, a "qualitative regression" is performed, relating the variables to be predicted (contained in the second set) with the "predictors" (the observable variables). On the grounds of the previously derived relationship, the risk of breakage in a new case can be evaluated, given observable variables. The method was applied in a case study regarding a set of 13 test sites where the ranking of risk obtained was validated by expert knowledge. Once validated, the procedure was included in the final output of the e-EcoRisk UE project (A Regional Enterprise Network Decision-Support System for Environmental Risk and Disaster Management of Large-Scale Industrial Spills), allowing for a dynamic historical database updating and providing a prompt rough risk evaluation for a new case. The aim of this section of the global project is to provide a quantified context where failure cases occurred in the past for supporting analogue reasoning in preventing similar situations.     

Talking about race using critical race theory: recent trends in the Journal of Marital and Family Therapy

This study uses critical race theory as an interpretive lens to critique recent race related articles in the Journal of Marital and Family Therapy (JMFT). Our primary goal is to contribute to and inspire dialogue about the perspectives marriage and family therapists (MFTs) are taking in relationship to race. We situate our exploration within the broader context of continuing professional education. We describe the main themes of critical race theory and use them as the conceptual framework. Analyzing 127 articles, we found that only topics related to couples and divorce occurred more frequently than race and social justice. Within the articles on race, evidence suggests that issues of race and racism are emerging as key informants of MFT practice. We point to areas for consideration in future MFT research and practice.     

Substance use, self-esteem, and depression among Asian American adolescents

The relationship of self-esteem and depression with alcohol, tobacco, and other drug (ATOD) use was tested in a California statewide sample of more than 4,300 Asian American high school students comprising five subgroups: Chinese, Japanese, Korean, Filipino, and Vietnamese. Estimated prevalence rates of alcohol, tobacco, and marijuana use among males and females from these Asian American subgroups are presented. Correlations revealed that cigarette, alcohol, and marijuana use were generally more related to high depression and low self-esteem in females than in males. Logistic regression analysis with only the female subjects investigated whether the relationship between the psychological variables and ATOD use was maintained even after controlling for traditionally important constructs in ATOD use (grade level in school, born in the United States, ethnicity, and ATOD use by friends). These results indicated that for females, depression was significantly related to alcohol and tobacco use, but self-esteem was not. Neither self-esteem nor depression was a significant contributor to marijuana use. Issues related to the application of these results are discussed.     

Gaze toward and avoidance of the handicapped: A field experiment

Kleck has discovered more eye contact directed toward a handicapped than a nonhandicapped confederate. He suggested that this was due to the information seeking function of eye contact. Langer et al. argued that this occurred because a handicap is a novel stimulus and that, when socially acceptable, people are motivated to look at something unusual. The present study posited that Kleck's findings occurred because of the experimental setting and that the Langer et al. hypothesis holds true only when interaction with the handicapped person will not occur. A field experiment indicated less gaze toward and more avoidance of handicapped than nonhandicapped confederates when conversation was required and more staring toward the handicapped than the nonhandicapped when conversation was not likely.Portions of this article were reported by Teresa L. Thompson and Bonnie Bell Cundiff, Communication between the handicapped and nonhandicapped: Avoidance and uncertainty, Presented at the Annual Convention of the International Communication Association, Philadelphia, 1979. The author would like to thank Louis P. Casella for helpful assistance.     

On the number of local minima for the multidimensional assignment problem

The Multidimensional Assignment Problem (MAP) is an NP-hard combinatorial optimization problem occurring in many applications, such as data association, target tracking, and resource planning. As many solution approaches to this problem rely, at least partly, on local neighborhood search algorithms, the number of local minima affects solution difficulty for these algorithms. This paper investigates the expected number of local minima in randomly generated instances of the MAP. Lower and upper bounds are developed for the expected number of local minima, E[M], in an MAP with iid standard normal coefficients. In a special case of the MAP, a closed-form expression for E[M] is obtained when costs are iid continuous random variables. These results imply that the expected number of local minima is exponential in the number of dimensions of the MAP. Our numerical experiments indicate that larger numbers of local minima have a statistically significant negative effect on the quality of solutions produced by several heuristic algorithms that involve local neighborhood search.Partially supported by the NSF grant DMI-0457473.     

Predictors of Quality of Life in Different Age Groups Across Adulthood

This study examines the Quality of Life (QOL) of 374 individuals from a generational perspective. Using a nonexperimental design and multiple regression analyses, the results indicated that social support is the highest preditor of QOL for all generations. As for specific generational groups, in addition to social support, income was observed as a QOL predictor for young adults; marital status was a significant predictor for the middle-aged adults, and income emerged as the important predictor for older adults. These results offer valuable insights for the planning and implementation of Intergenerational Education Programs with the aim of increasing QOL across adulthood.     

The municipal solid waste and the quality of life of collectors of recyclable materials in Juiz de Fora, Minas Gerais

The generation growing and diversified of Municipal Solid Waste is configured as an environmental problem, economic and social deterioration, especially, by application of inappropriate management of them. Faced with this urban context, the research in development presents as specific objective assessment of the quality of life of the gatherers of recyclable materials were active in the city of Juiz de Fora, in the brazilian state of Minas Gerais. In addition, the objective is, still, the recognition of the activity of sorting performed by "scavengers" in order to maximize the reduction, reuse and recycling energy and material waste daily. The proposed methodology is based on the application of the questionnaire Word Health Organization Quality of Life (WHOQOL-100), prepared by the World Health Organization, in order to value the quality of life of the gatherers of recyclable materials, involved, even in educational workshops in order to discuss and organize strategies of health care and scouting to the basement to public policies.