Moments of scale mixtures of skew-normal distributions and their quadratic forms

We obtain the first four moments of scale mixtures of skew-normal distributions allowing for scale parameters. The first two moments of their quadratic forms are obtained using those moments. Previous studies derived the moments, but all relevant results do not allow for scale parameters. In particular, it is shown that the mean squared error becomes an unbiased estimator of σ² with skewed and heavy-tailed errors. Two measures of multivariate skewness are calculated.     

Is Food Insecurity Associated with Depressive Symptoms in South Korea?

Emerging studies have suggested a possible link between food hardship and depression; however, empirical knowledge is limited. In South Korea, more public discussion has been conducted regarding the prevalence and consequences of food insecurity on mental health. To begin to address the knowledge gap, we applied family stress theory and investigated the association of food insecurity with depression in South Korea. We employed observational data from the Korea Welfare Panel Study, the first data to draw on food insecurity information from a nationally representative sample in Korea. Our sample consisted of 744 non‐elderly household heads. The independent variable “food insecurity” was measured using a six‐item scale adapted from the United States Department of Agriculture Food Security Scale. The dependent variable “depression” was measured using 11 questions from the Center for Epidemiologic Studies Depression Scale adapted for Koreans. After controlling for income, material hardship, and other factors, our ordinary least squares regression findings show that food insecurity significantly predicts depression. Our findings are consistent whether food insecurity is measured on a continuum or in categorical groups. More research and empirical evidence should be shared to provide legitimate grounds for policy interventions that address and prevent food insecurity and mental health issues.     

Sexy women sports fans: femininity,sexuality, and the global sport spectacle

In recent years the relationship between women and sport fandom has undergone significant shifts. The rapidly changing sphere of global sport is seen to offer women newly visible roles in the global sport economy as fans, broadcasters, celebrity athletes, and media personalities. In light of calls for greater inclusivity and diversity in sport, this paper examines the emergence of new forms of “sexually empowered” female fandom, which situate women as active participants in the sporting spectacle. Whereas sexy women who followed men’s sport or male athletes were once derided as “groupies,” thus socially marginalised and excluded from identification with sport fan communities, I argue that the sexy sport fan has emerged in the context of post-feminism as a visible and necessary type of feminine fan identity to meet the needs of the global sport economy. This study extends feminist sport media analysis beyond its focus on how female athletes are represented whilst also contributing new insights to sport fan research by analysing how female supporters are constructed through mediated accounts in terms of gender, sexuality, and nation.     

Social participation,health‐related behavior,and depression of older adults living alone in Korea

This study aims to identify the effects of social participation on depression among adults over 60 years old living alone in Korea, focusing on the mediating effect of health‐related behavior on the social participation–depression relationship. The study relies on secondary data analysis using the 6th wave of the Korea Longitudinal Study of Ageing, and structural equation modeling method was employed for analyses. The findings indicate that older adults' participation in religious and social gatherings decreases depressive symptoms. The study also finds that regular eating behavior, drinking, and exercise also act as significant mediators, as older adults' participation in social gatherings is associated with those health‐related behaviors and that they also reduce depression. The results suggest that social participation by older adults who live alone is crucial not only for providing them with support but also for encouraging health‐related activities that can have direct effects on their mental health. Implications for social work practice are also discussed.     

Online psychoeducation with parent management training: Examining the contribution of peer support

Psychoeducation is an empirically based intervention that is increasingly delivered online to individuals and groups. Low participation has been a problem for online designs that include peer support. New technology designs have been called for, and in response, we developed a model that synchronized the delivery of individual and group‐based psychoeducational activities for parent management training. We used a problem‐based learning strategy delivered to caregivers of youth demonstrating oppositional behaviours to encourage the development of helping processes and peer support. This mixed methods intervention study had high rates of participant retention and positive measurable changes for two of its three psychoeducational outcome measures. When we merged the study data, we observed that mutual aid—a frequently sought goal of group‐based interventions—contributed to participant outcomes.     

Differential Susceptibility to Parenting in Adolescent Girls: Moderation by Neural Sensitivity to Social Cues

This research examined whether heightened neural activation to social cues confers adjustment advantages in supportive social contexts but adjustment disadvantages in stressful social contexts. Forty‐five adolescent girls were exposed to social exclusion during an fMRI scan and reported on parent–child relationship quality and depressive symptoms. Stressful parent–child relationships predicted subsequent depressive symptoms in girls with high and moderate but not low dorsal anterior cingulate cortex, subgenual anterior cingulate cortex, and anterior insula activation during exclusion. In the context of supportive parent–child relationships, however, neural activation to exclusion predicted particularly low levels of depressive symptoms. This support for a biological sensitivity to context model suggests the possibility of redirecting adolescent girls’ neural sensitivity to social cues toward more positive adaptation.     

Posterior consistency in frailty models and simulation studies to test the presence of random effects

The estimation of random effects in frailty models is an important problem in survival analysis. Testing for the presence of random effects can be essential to improving model efficiency. Posterior consistency in dispersion parameters and coefficients of the frailty model was demonstrated in theory and simulations using the posterior induced by Cox’s partial likelihood and simple priors. We also conducted simulation studies to test for the presence of random effects; the proposed method performed well in several simulations. Data analysis was also conducted. The proposed method is easily tractable and can be used to develop various methods for Bayesian inference in frailty models.     

Principal weighted logistic regression for sufficient dimension reduction in binary classification

Sufficient dimension reduction (SDR) is a popular supervised machine learning technique that reduces the predictor dimension and facilitates subsequent data analysis in practice. In this article, we propose principal weighted logistic regression (PWLR), an efficient SDR method in binary classification where inverse-regression-based SDR methods often suffer. We first develop linear PWLR for linear SDR and study its asymptotic properties. We then extend it to nonlinear SDR and propose the kernel PWLR. Evaluations with both simulated and real data show the promising performance of the PWLR for SDR in binary classification.     

Caffeine intake is not associated with serum testosterone levels in adult men: cross-sectional findings from the NHANES 1999–2004 and 2011–2012

Objective: The association of caffeine intake with testosterone remains unclear. We evaluated the association of caffeine intake with serum testosterone among American men and determined whether this association varied by race/ethnicity and measurements of adiposity.

Methods: Data were analyzed for 2581 men (≥20?years old) who participated in the cycles of the NHANES 1999–2004 and 2011–2012, a cross-sectional study. Testosterone (ng/mL) was measured by immunoassay among men who participated in the morning examination session. We analyzed 24-h dietary recall data to estimate caffeine intake (mg/day). Multivariable weighted linear regression models were conducted.

Results: We identified no linear relationship between caffeine intake and testosterone levels in the total population, but there was a non-linear association (p_nonlinearity?p_nonlinearity?≤?.03 both) and only among men with waist circumference <102?cm and body mass index <25?kg/m² (p_nonlinearity?Conclusion: No linear association was identified between levels of caffeine intake and testosterone in US men, but we observed a non-linear association, including among racial/ethnic groups and measurements of adiposity in this cross-sectional study. These associations are warranted to be investigated in larger prospective studies.     

US foreign aid and economic policy concessions*

Why do donors continue to provide foreign aid despite its failure to help poor countries over the past several decades? While some scholars argue that foreign aid is purely for humanitarian purposes, others assert that such aid serves as a tool to pressure recipient countries into accepting policy concessions. In this study, we subject these arguments to empirical testing using a dataset that integrates the amount of US aid and economic policies of recipient countries for 1995–2012. The findings suggest that aid decisions correspond to the interests of the United States, such as policy concessions in economic and business liberalization. However, an increase in US aid is not directly associated with further economic reforms in recipient countries. We conclude that US foreign aid programmes are strategic in nature and successful not in alleviating economic problems in recipient countries but, at the very least, in buying their policy compliance.