Effectiveness of combinations of Gaussian graphical models for model building

Combining statistical models is an useful approach in all the research area where a global picture of the problem needs to be constructed by binding together evidence from different sources [M.S. Massa and S.L. Lauritzen Combining Statistical Models, M. Viana and H. Wynn, eds., American Mathematical Society, Providence, RI, 2010, pp. 239–259]. In this paper, we investigate the effectiveness of combining a fixed number of Gaussian graphical models respecting some consistency assumptions in problems of model building. In particular, we use the meta-Markov combination of Gaussian graphical models as detailed in Massa and Lauritzen and compare model selection results obtained by combining selections over smaller sets of variables with selection results over all variables of interest. In order to do so, we carry out some simulation studies in which different criteria are considered for the selection procedures. We conclude that the combination performs, generally, better than global estimation, is computationally simpler by virtue of having fewer and simpler models to work on, and has an intuitive appeal to a wide variety of contexts.     

Conventional and expanded adverse childhood experiences (ACEs) and maternal functioning among low-income Black mothers

A paucity of research has examined the individual and cumulative effects of conventional and expanded adverse childhood experiences (ACEs) on maternal functioning, especially among low-income Black mothers. Using self-report data from a subsample of Black mothers (N = 157) who participated in a larger study to evaluate the effectiveness of an urban public prekindergarten program in the mid-Atlantic region of the United States, we examined the prevalence of ACEs and the individual and cumulative effects of conventional (i.e., family trauma and dysfunction) and expanded (i.e., community stressors) ACEs on depression and health among low-income Black mothers. Findings indicated that Black mothers had more exposure to expanded than conventional ACEs. Hierarchical regression analyses revealed that experience of physical neglect was significantly associated with depression and physical abuse with compromised health, and perceived experience of racism was a predictor of depression and compromised health. More conventional and expanded ACEs were associated with clinical levels of depression and compromised health. Findings highlight the need for more research related to the impact of ACEs, especially expanded ACEs, on mental and behavioural health outcomes. Additionally, our findings indicate the need for more trauma-informed care to reduce and address the impact of individual and community-level adversities on low-income Black mothers.     

Habitat patch size and tree species richness shape the bird community in urban green spaces of rapidly urbanizing Himalayan foothill region of India

Urban Ecosystems - Rapid urbanization is emerging as one of the leading threats to the biodiversity globally. But is especially a cause of concern for tropical countries which are urbanizing much...     

RELATIVE RISK AVERSION IS CONSTANT: EVIDENCE FROM PANEL DATA

Most classical tests of constant relative risk aversion (CRRA) based on individual portfolio composition use cross‐sectional data. Such tests must assume that the distributions of wealth and preferences are independent. We use panel data to analyze how individuals’ portfolio allocation between risky and riskless assets varies in response to changes in total financial wealth. We find the elasticity of the risky asset share to wealth to be small and statistically insignificant, supporting the CRRA assumption; this finding is robust when the sample is restricted to households experiencing large income variations. In addition, we find a small but significant negative correlation between wealth and risk aversion. Various extensions are discussed.     

Positive and negative intergroup contact in school and out-of-school contexts: A longitudinal approach to spillover effects

This study aims to tackle positive and negative intergroup contact in school and out-of-school contexts to test whether a spillover effect (i.e., the extent to which experiences that individuals have in one context spill over into another) applies to intergroup contact. Participants were 984 adolescents (M_age = 14.66; 62.7% female; 24.8% ethnic minority). Results indicated that positive contact in school was related over time to higher positive contact in out-of-school contexts and vice versa (i.e., valence consistent spillover effect). Positive contact in school was linked over time to lower negative contact in out-of-school contexts (i.e., valence inconsistent spillover effect). Overall, this study provides novel insights into the transmission of adolescents' intergroup contact across socialization contexts by emphasizing the leading role of positive contact in schools.