Parameter estimation in high dimensional Gaussian distributions

In order to compute the log-likelihood for high dimensional Gaussian models, it is necessary to compute the determinant of the large, sparse, symmetric positive definite precision matrix. Traditional methods for evaluating the log-likelihood, which are typically based on Cholesky factorisations, are not feasible for very large models due to the massive memory requirements. We present a novel approach for evaluating such likelihoods that only requires the computation of matrix-vector products. In this approach we utilise matrix functions, Krylov subspaces, and probing vectors to construct an iterative numerical method for computing the log-likelihood.     

Assessing Overweight,Obesity, Diet,and Physical Activity in College Students

Abstract

The authors surveyed 738 college students aged 18 to 27 years to assess overweight, obesity, dietary habits, and physical activity. They used BMI (body mass index) > 25 kg/m² or BMI > 85th percentile and BMI > 30 kg/m¹ or BMI > 95th percentile to estimate overweight and obesity in those aged < 19 years. To define overweight and obesity in those > 20 years, they used BMI > 25 kg/m² and > 30 kg/m². They found overweight rates of 21.6% using BMI directly and 16.2% using BMI percentile and obesity rates of 4.9% using BMI directly and 4.2% using BMI percentile. More than 69% of the participants reported < 5 servings of fruits and vegetables per day and more than 67% reported < 20 g of fiber per day; participants reported physical activity on fewer than 3 d/wk. Most college students are not meeting dietary and physical activity guidelines, suggesting the need for prevention interventions and increased understanding of overweight in college students.     

Postdivorce Relationships in Families and Children's Psychosocial Adjustment

Divorced mothers and their school-aged children in 50 single-mother families and 37 stepfather families reported on mothers' ex-partner relationships, children's relationships with both parents, and children's well-being. A 2 (family structure) × 2 (gender) multivariate analysis of variance revealed a main effect of gender: Mothers with sons report higher levels of ex-partner relationship satisfaction. An interaction effect was also found: Boys in single-mother families report more acceptance and fewer conflicts than boys in stepfather families. Multiple regression analysis revealed that mother–ex-partner relationships are associated with children's problem behavior, whereas child–nonresidential father relationships are associated with positive aspects of children's well-being. The results indicate that family structure itself is not associated with child adjustment. What matters most is the quality of family relationships.     

Negotiating Ethnic Identity in the College Korean Language Classes

This article examines the ways in which second-generation Korean-American students form and transform their senses of ethnicity through their participation in Korean language classes at the University of Illinois, Urbana-Champaign. These classes were largely populated by second-generation Korean-Americans. Called the "New Second Generation," these Korean-American students, who have "successfully" proceeded through the American educational system, show that adaptation to the host society does not necessarily lead to assimilated American identity, and that learning Korean (a "heritage" language) does not necessarily lead to homogeneous ethnic identity formation. Although "heritage" (or "ethnic") language has often been taken up as a symbol for group maintenance, my study shows that actual interaction with the language is complexly and heterogeneously experienced among the group members, especially in relation to the ethnic identity formation process. Korean classes (as a transnational social field) contain complicated and contradictory characteristics, resulting from their complex mixture of class participants, their institutional location, and their national and transnational situation. Korean-American language learners negotiate their sense of ethnic identity by interacting with social meanings initiated from words, passages, illustrations, and texts. Furthermore, Korean-American student's language performance and cultural tastes, which are perceived and evaluated by themselves and others, differently locate these students on a continuum of "Koreanness" and "Americanness," reflecting different relationships to Korea and different senses of being Korean.     

Galvão among the cannibals: The emotional constitution of colonial power

Colonial domination was not a simple act of violence. Rather, it was written into the bodies and the hearts of the people—"white,” “black,” or whatever other combination might be held to exist. Using the example of the Portuguese African colonies in mid‐twentieth century, this paper aims at illuminating the emotional constitution of colonial power by exploring the uses of the trope cannibalism. In order to do that, recourse is taken to a reading of the non‐fictional writings of Henrique Galvão—one of the most active Portuguese intellectuals and Africanist politicians of the period. Subaltern persons were attributed terrible and mysterious tendencies that escaped simple rationality (they were zombified). In this way, a phantasmagoria of subalternity was constituted that, through fear, transformed domination into a structure of emotions. Thus, the repressive attitudes of colonial power were made to appear natural and unavoidable.     

Comparing Ourselves to Others: International Knowledge and Attitudes

The authors focus on the collaboration between a university methods professor and two classroom teachers in teaching social studies methods as a way of bridging the gap between university preparation for teaching social studies and putting that preparation into practice in elementary classrooms. The teachers offer recommendations from their own teaching experiences for how preservice teachers can find time for powerful social studies teaching despite pressures to meet the requirements of No Child Left Behind in literacy and mathematics. They integrate social studies with literacy and math, use "teachable moments" and transitions between subjects, and incorporate social studies research with computer and media skills. In addition, they employ class meetings to practice the democratic processes of collectively setting and revising class rules, accepting responsibility for those rules, and working together to solve classroom problems. Informal feedback from the preservice teachers reflects their appreciation of advice from classroom teachers with current experience in addressing the challenge of making time for powerful social studies teaching.     

User and Carer Experiences of International Social Care Workers in England: Listening to their Accounts of Choice and Control

Abstract

This paper develops a typology of people using social care services’ preferences for care workers and satisfaction with social care services from a large multimethod study that explored international recruitment to the English social care sector (home and health care, including residential homes). We developed this typology with two questions in mind: (a) what led to satisfaction of care and (b) what led to preference and satisfaction with workers? Data were collected from face-to-face interviews with 35 people who were using social care services and carers (2007–2009) and these data were used to develop the typology. Using the theoretical concept of homophily, we explored contentions that people might prefer to receive care and support from individuals resembling themselves. We observed that preferences for care workers and satisfaction with social care services may be linked, but highlighted that the concept of meeting a preference is personal to the individual. The implications of users’ preferences for certain care workers at a time where policy is promoting greater consumer-led care or self-directed support are discussed.     

Partner support during the prenatal testing period after assisted conception

Background

Pregnancy after infertility is a challenging experience. The first-trimester screening test may add stress. Partner support reduces psychological distress in pregnant women after spontaneous conception. No data are available for women who conceive via assisted reproductive technology.

Differences between sexually victimized and nonsexually victimized male adolescent sexual abusers: developmental antecedents and behavioral comparisons

This study compares sexually victimized and nonsexually victimized male adolescent sexual abusers on a number of variables. Self-report measures were administered to 325 male sexually abusive youth (average age 16) in six residential facilities in the Midwest, 55% of whom reported sexual victimization. The results indicate that the sexually victimized sexual abusers have more severe developmental antecedents (trauma, family characteristics, early exposure to pornography and personality) and recent behavioral difficulties (characteristics of sexual aggression, sexual arousal, use of pornography, and nonsexual criminal behavior) than the nonsexually victimized group. Results are contrasted with recent typological research, which found no relationship between sexual victimization and subtype membership. Treatment, research, and theoretical implications are discussed.     

Turning the Car Inside Out: Transport, Equity and Environment

"Turning the car inside out" describes how the environmental damage and social exclusion inflicted by the car can only be seen from outside the car. It explains how car use has reshaped land, time use, social relations and economic patterns. It creates ever more pressures for increased car use, yet inevitably leaves the people temporarily or permanently excluded from cars having to negotiate car distances and times. The worst scenario of car saturation is rejected as untenable both because of the permanent social and environmental impact, but also the self-defeating nature of the quest for mobility.