Gamma-based clustering via ordered means with application to gene-expression analysis

Discrete mixture models provide a well-known basis for effective clustering algorithms, although technical challenges have limited their scope. In the context of gene-expression data analysis, a model is presented that mixes over a finite catalog of structures, each one representing equality and inequality constraints among latent expected values. Computations depend on the probability that independent gamma-distributed variables attain each of their possible orderings. Each ordering event is equivalent to an event in independent negative-binomial random variables, and this finding guides a dynamic-programming calculation. The structuring of mixture-model components according to constraints among latent means leads to strict concavity of the mixture log likelihood. In addition to its beneficial numerical properties, the clustering method shows promising results in an empirical study.Comment: Published in at http://dx.doi.org/10.1214/10-AOS805 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

In Search of the Roots of Professional Ethics: The New Ethical Imperatives*

The purpose of this article is to encourage the creation of an ongoing dialogue on the ethical aspects of professional life--which turn out to be, at present, the ethical aspects of public life in general. This paper, originally sponsored by Sacred Heart University\u27s Center for Applied Ethics, was delivered at the University in the fall, 1981

The Imperative to Restore Nature: Some Philosophical Questions

The purpose of WMU\u27s Center for the Study of Ethics is to encourage and support research, teaching, and service to the university and community in areas of applied and professional ethics. These areas include, but are not restricted to: business, education, engineering, government, health and human services, law, media, medicine, science, and technology

Choice of College Major: An Exploration of Appalachian Female Choice of an Early Childhood Education Major

First generation Appalachian female students are exposed to gender differences in roles and career choices that are modeled in the family. A case study approach was used to obtain qualitative data from five students at Eastern Kentucky University and their mothers regarding why these students chose to major in child development and early childhood education. Bandura\u27s Social Cognitive Learning Theory and Bronfenbrenner\u27s Ecological Systems Theory were used as frameworks for the study. The findings of the study are valuable in advising college students\u27 on selection of a college major and recruitment of dedicated child development and early childhood education professionals through understanding the influences and motivations of the five students and their mothers

Turnaround time and market capacity in contract cheating

Contract cheating is the process whereby students auction off the opportunity for others to complete assignments for them. It is an apparently widespread yet under-researched problem. One suggested strategy to prevent contract cheating is to shorten the turnaround time between the release of assignment details and the submission date, thus making it difficult for students to make arrangements with contractors. Here, we outline some characteristics of the current market for contract cheating and demonstrate that short turnaround times are unlikely to prevent contract cheating because requested turnaround times for university-level assignments completed via contract cheating are already short (average 5 days). In addition, for every contractor awarded a job, there are an average of 10 others offering to complete it within the specified time suggesting that there is abundant excess capacity in the market

Reflections on Teaching with a Standards-Based Curriculum: A Conversation Among Mathematics Educators

Many teachers and researchers have written about the challenges inherent in adopting new teaching practices in mathematics classrooms (e.g., Chazan, 2000; Clarke, 1997; Heaton, 2000). The authors of this article, all with secondary mathematics teaching experience, are convinced by research suggesting that Standards-based mathematics curricula are beneficial for student learning.1 However, the first three authors had not used such curriculum materials in their own classrooms, and we desired experience using a Standards-based mathematics curriculum with secondary students. To this end, we taught a week-long summer course with a focus on linear functions to high school students who had previously struggled with algebra and volunteered to participate

Is this the life that I want to have? : values-based self-affirmation for young people with dermatological conditions

Values as therapeutic Jocil processes and motivators: a systematic review. A systematic search revealed 19 papers pertaining to therapeutic use of values. Six reported significant positive correlations between values-based living and well-being. Twelve of the remaining 13 presented evidence that supported the use of valuesbased interventions to: enable the adaptive acceptance of distress (two), increase values clarity and values-based living (five of six), improve psychosocial/physical function (two), and increase tolerance of threats to self worth (three). Further research is required, particularly outside the populations of students and peopl'e with chronic health problems. A theoretical model is presented whereby values-based interventions may improve well-being through two compatible pathways: increasing values-based living and reducing psychological threat to self worth. Section two: Research report Values-based self-affirmation Jor young people who experience skin-related distress A multiple case studies approach was used to evaluate a values-based self-affirmation intervention using nomothetic measures, idiographic daily repeated measures and qualitative data. Participants comprised 11 young people with psychosocial distress self-attributed to their dermatological condition. Depression and anxiety reduced significantly at the group level (p<O.OS), and individual level (N=7). Skin-related frustration and restrictions reduced, whilst reported preoccupation and concealment increased. Qualitative data indicated increased values-based living and reduced skin-related threats to self-worth post-inte'rvention. Participants identified empathic discussion to be more important than self-affirmation. Skin-related distress in young people can be reduced using a simple intervention that could be implemented by nursing staff. Further research is required to clarify the active components and mechanisms of change

Ingenuity in Action: Connecting Tinkering to Engineering Design Processes

The Lawrence Hall of Science, a science center, seeks to replicate real-world engineering at the Ingenuity in Action exhibit, which consists of three open-ended challenges. These problems encourage children to engage in engineering design processes and problem-solving techniques through tinkering. We observed and interviewed 112 visitor groups at the exhibit to understand how children engage in engineering behaviors extracted from the steps of a design process and to what extent they are aware of these processes. We found that all but one group exhibited engineering behaviors, and facilitation and collaboration positively correlated with engineering behaviors. The Ingenuity in Action exhibit establishes a successful framework of designing for engineering learning

Human cytomegalovirus epidemiology and relationship to tuberculosis and cardiovascular disease risk factors in a rural Ugandan cohort.

Human cytomegalovirus (HCMV) infection has been associated with increased mortality, specifically cardiovascular disease (CVD), in high-income countries (HICs). There is a paucity of data in low- and middle-income countries (LMICs) where HCMV seropositivity is higher. Serum samples from 2,174 Ugandan individuals were investigated for HCMV antibodies and data linked to demographic information, co-infections and a variety of CVD measurements. HCMV seropositivity was 83% by one year of age, increasing to 95% by five years. Female sex, HIV positivity and active pulmonary tuberculosis (TB) were associated with an increase in HCMV IgG levels in adjusted analyses. There was no evidence of any associations with risk factors for CVD after adjusting for age and sex. HCMV infection is ubiquitous in this rural Ugandan cohort from a young age. The association between TB disease and high HCMV IgG levels merits further research. Known CVD risk factors do not appear to be associated with higher HCMV antibody levels in this Ugandan cohort

Neonatal vaccination of low birthweight infants in Ghana.

OBJECTIVES: Global vaccination policy advocates for identifying and targeting groups who are underserved by vaccination to increase equity and uptake. We investigated whether birth weight and other factors are determinants of neonatal BCG vaccination in order to identify infants underserved by vaccination. METHODS: We used logistic regression to calculate adjusted ORs (AORs) for the association between birth weight (categorised as non-low birth weight (NLBW) (≥2.50 kg) and low birth weight (LBW) (2-2.49 kg, 1.50-1.99 kg and 0.19). Facility-born infants were vaccinated at a mean of 6 days, suggesting that they were not vaccinated in the facility at birth but were referred for vaccination. CONCLUSIONS: LBW is a risk factor for neonatal under-vaccination, even for facility-born infants. Ensuring vaccination at facility births would substantively improve timing and equitable BCG vaccination