On sequential closed testing dose groups with a control

Methods for a sequential test of a dose-response effect in pre-clinical studies are investigated. The objective of the test procedure is to compare several dose groups with a zero-dose control. The sequential testing is conducted within a closed family of one-sided tests. The procedures investigated are based on a monotonicity assumption. These closed procedures strongly control the familywise error rate while providing information about the shape of the dose-responce relationship. Performance of sequential testing procedures are compared via a Monte Carlo simulation study. We illustrae the procedures by application to a real data set.     

The estimation of treatment effect for the censored bivariate data under the univariate censoring

This paper establishes a nonparametric estimator for the treatment effect on censored bivariate data under unvariate censoring. This proposed estimator is based on the one from Lin and Ying(1993)'s nonparametric bivariate survival function estimator, which is itself a generalized version of Park and Park(1995)' quantile estimator. A Bahadur type representation of quantile functions were obtained from the marginal survival distribution estimator of Lin and Ying' model. The asymptotic property of this estimator is shown below and the simulation studies are also given     

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.     

Reinvigorating the social contract and strengthening social cohesion: Social protection responses to COVID-19

The COVID-19 pandemic has exposed the vulnerability of those who are inadequately covered by social protection in more and less developed countries alike, and has exacerbated the fragility of a social contract that was already under strain in many countries. A weak social contract in the context of an exceptional crisis poses a very real risk to social cohesion. Nevertheless, many States have reasserted themselves as the guarantor of rights by protecting public health and incomes. By sustaining these measures, economic recovery will be supported which will help minimize risks that may weaken social cohesion. However, this is a fast-moving, inherently unstable and protracted crisis. Social protection stands at a critical juncture. Decisive policy action will be required to strengthen social protection systems, including floors, as one of the cornerstones of a reinvigorated social contract.     

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.     

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.     

On nonlinear multi-covering problems

In this paper we define the exact k-coverage problem, and study it for the special cases of intervals and circular-arcs. Given a set system consisting of a ground set of n points with integer demands \(\{d_0,\dots ,d_{n-1}\}\) and integer rewards, subsets of points, and an integer k, select up to k subsets such that the sum of rewards of the covered points is maximized, where point i is covered if exactly \(d_i\) subsets containing it are selected. Here we study this problem and some related optimization problems. We prove that the exact k-coverage problem with unbounded demands is NP-hard even for intervals on the real line and unit rewards. Our NP-hardness proof uses instances where some of the natural parameters of the problem are unbounded (each of these parameters is linear in the number of points). We show that this property is essential, as if we restrict (at least) one of these parameters to be a constant, then the problem is polynomial time solvable. Our polynomial time algorithms are given for various generalizations of the problem (in the setting where one of the parameters is a constant).