Dimension-wise sparse low-rank approximation of a matrix with application to variable selection in high-dimensional integrative analyzes of association

Many research proposals involve collecting multiple sources of information from a set of common samples, with the goal of performing an integrative analysis describing the associations between sources. We propose a method that characterizes the dominant modes of co-variation between the variables in two datasets while simultaneously performing variable selection. Our method relies on a sparse, low rank approximation of a matrix containing pairwise measures of association between the two sets of variables. We show that the proposed method shares a close connection with another group of methods for integrative data analysis – sparse canonical correlation analysis (CCA). Under some assumptions, the proposed method and sparse CCA aim to select the same subsets of variables. We show through simulation that the proposed method can achieve better variable selection accuracies than two state-of-the-art sparse CCA algorithms. Empirically, we demonstrate through the analysis of DNA methylation and gene expression data that the proposed method selects variables that have as high or higher canonical correlation than the variables selected by sparse CCA methods, which is a rather surprising finding given that objective function of the proposed method does not actually maximize the canonical correlation.     

Social Networks Derived from Affiliations and Friendships, Multi-informant and Self-reports: Stability, Concordance, Placement of Aggressive and Unpopular Children, and Centrality

This study compares three variations in how researchers construct middle childhood social networks: (1) with friendships or affiliations as a relational tie; (2) with children providing self reports of relationships, or in addition, multi-informant reports of relationships in which they are not involved; and (3) whether network computation is correlational or distance-based . The sample was 357 fourth- and fifth-grade students in 17 classrooms. The strongest differences were between self-reported friendship and affiliative networks. Results showed that compared with affiliations, friendship networks had smaller groups, more isolates, and lower fall-to-spring stability. Agreement in social placement between friendship and affiliative networks was generally average, but poor for unpopular and aggressive children. Multi-informant affiliative networks were most robust in their positioning of aggressive children. Multi-informant centrality was uniquely uncorrelated with aggression. Network computation differences were not substantial. Discussion focuses on recommendations for research and the educational promise of network technology.     

Competing for the diaspora's influence at home: party structure and transnational campaign activity in El Salvador

ABSTRACT

How do parties in migrant-sending countries engage with the diaspora? Migrants exercise an increasingly important voice in electoral politics in their home countries, though they often either cannot legally vote or vote in very low numbers, yet parties attempt to leverage the influence they believe migrants have over voters at home. However the degree and manner by which parties reach out to diaspora citizens varies widely. A case study of El Salvador points to party organisation as a determinant of variation among parties in diaspora campaigning, based on interviews with Salvadoran party elites in the U.S. and El Salvador, party documents, and historical comparison of campaign activities of El Salvador's two major parties, ARENA and FMLN, over three presidential elections and one mayoral election. FMLN, with a hierarchical model and base committee structure, more effectively mobilizes diaspora support while ARENA, with a horizontal model and sectoral structure, exhibits difficulties in party-diaspora coordination and largely makes indirect and symbolic references to diaspora issues.     

Divorce as risky behavior

Given that divorce often represents a high-stakes income gamble, we ask how individual levels of risk tolerance affect the decision to divorce. We extend the orthodox divorce model by assuming that individuals are risk averse, that marriage is risky, and that divorce is even riskier. The model predicts that conditional on the expected gains to marriage and divorce, the probability of divorce increases with relative risk tolerance because risk averse individuals require compensation for the additional risk that is inherent in divorce. To implement the model empirically, we use data for first-married women and men from the 1979 National Longitudinal Survey of Youth to estimate a probit model of divorce in which a measure of risk tolerance is among the covariates. The estimates reveal that a 1-point increase in risk tolerance raises the predicted probability of divorce by 4.3% for a representative man and by 11.4% for a representative woman. These findings are consistent with the notion that divorce entails a greater income gamble for women than for men.     

Risk factors for child maltreatment in South Korea: An investigation of a nationally representative sample

This study investigated the risk factors associated with the occurrence of child physical and psychological abuse in South Korea based on the ecological theory of child maltreatment. A subsample of 3‐ to 18‐year‐old children from “A Study on the Current State of Child Abuse and Neglect,” a nationally representative study on child abuse and neglect, was utilized for secondary data analysis. The sample was divided into two age groups (third graders in elementary school and below and fourth graders and above). We utilized hierarchical logistic regression for each age group separately to analyze the data. The variables at each level of the system (i.e., ontogenic development, microsystem, and exosystem) were entered into the model in sequential order. The results showed the common risk factors for both age groups are the caregiver's experience of abuse in childhood, the child's problem behavior, exposure to domestic violence, community size, and informal social control. The child's age was also significant in both groups but in the opposite direction. Social support was a significant predictor for the younger age group only, while the caregiver's level of education was significant for the older age group only. Implications for future research and practice are discussed based on the study results.     

Trajectory of problem behaviours of Korean adopted children: using piecewise hierarchical linear growth modelling

This study examined the trajectory of problem behaviours in domestically adopted children in South Korea as they aged. This study used the Panel Study on Korean Adopted Children's longitudinal, three‐wave data (2006, 2008 and 2010). Although data were collected at three time points, our data consisted of six time points, which covered the 5–10 years age range of the adopted children at the time of survey. One hundred sixty‐four children were included in the analysis, 75 of whom contributed to one time point, 74 to two time points and 15 to three time points. The trajectory of the problem behaviours of adopted children was examined using a piecewise hierarchical linear growth model. Because the initial exploration of the data suggested non‐linear changes in behaviour problems over time, we split the growth trajectory into two time periods: Time 1 (5–7 years) and Time 2 (7–10 years). A two‐rate model was used to estimate separate slopes for the two time periods. Results showed that the externalizing and internalizing problems of adopted children have different trajectories. Internalizing problems did not show significant changes after 5 years of age, while externalizing problems increased until 7 years of age and decreased significantly thereafter.     

What Affects the Happiness of Adopted Children in South Korea? Does the Adoption Matter to Their Happiness?

Child and Adolescent Social Work Journal - Since the ultimate goal of adoption is to provide children a happy life in a stable family environment, our major concern is children’s happiness...     

Social investment effects of public education,health care,and welfare service expenditures on economic growth

The purpose of this study is to theoretically and empirically examine whether public spending in education, health care, and welfare service operates as a fruitful investment in welfare states, which has been implied in the literature of social investment arguments. Based on comprehensive review of existing literature, this study suggested a tripartite mechanism of social investment effect of such spending, that is “enhancement of human capital,” “support for labor force participation,” and “job creation.” To find the empirical evidence, a pooled time‐series cross‐section analysis was conducted with the data of 15 advanced welfare states from 1980 to 2015 using estimation technique of fixed‐effect model. The results confirmed that public spending in education, health care, and welfare service had a positive medium‐term as well as long‐term effect on economic performance, while cash‐type welfare spending had an obscure or no visible effect on economy. Government consumption that is a proxy and control variable of size of the welfare state showed a positive effect on real GDP in the medium term but a negative effect in the long run. In conclusion, this study suggests that reinforcing social services should be recognized and dealt with as essence of social investment strategy.     

The Effectiveness of Risk Management: An Analysis of Project Risk Planning Across Industries and Countries

This article examines the effectiveness of current risk management practices to reduce project risk using a multinational, multi‐industry study across different scenarios and cultures. A survey was administered to 701 project managers, and their supervisors, in seven industries and three diverse countries (New Zealand, Israel, and Japan), in multiple languages during the 2002–2007 period. Results of this study show that project context—industry and country where a project is executed—significantly impacts perceived levels of project risk, and the intensity of risk management processes. Our findings also suggest that risk management moderates the relationship between risk level and project success. Specifically, we found that even moderate levels of risk management planning are sufficient to reduce the negative effect risk levels have on project success.