Bayesian nonparametric modelling of the link function in the single-index model using a Bernstein–Dirichlet process prior

This paper proposes the use of the Bernstein–Dirichlet process prior for a new nonparametric approach to estimating the link function in the single-index model (SIM). The Bernstein–Dirichlet process prior has so far mainly been used for nonparametric density estimation. Here we modify this approach to allow for an approximation of the unknown link function. Instead of the usual Gaussian distribution, the error term is assumed to be asymmetric Laplace distributed which increases the flexibility and robustness of the SIM. To automatically identify truly active predictors, spike-and-slab priors are used for Bayesian variable selection. Posterior computations are performed via a Metropolis-Hastings-within-Gibbs sampler using a truncation-based algorithm for stick-breaking priors. We compare the efficiency of the proposed approach with well-established techniques in an extensive simulation study and illustrate its practical performance by an application to nonparametric modelling of the power consumption in a sewage treatment plant.     

The nested joint clustering via Dirichlet process mixture model

This article focuses on the clustering problem based on Dirichlet process (DP) mixtures. To model both time invariant and temporal patterns, different from other existing clustering methods, the proposed semi-parametric model is flexible in that both the common and unique patterns are taken into account simultaneously. Furthermore, by jointly clustering subjects and the associated variables, the intrinsic complex shared patterns among subjects and among variables are expected to be captured. The number of clusters and cluster assignments are directly inferred with the use of DP. Simulation studies illustrate the effectiveness of the proposed method. An application to wheal size data is discussed with an aim of identifying novel temporal patterns among allergens within subject clusters.     

A dimensionality reduction method of continuous dependent variables based supervised Laplacian eigenmaps

Dimensionality reduction is one of the important preprocessing steps in high-dimensional data analysis. In this paper we propose a supervised manifold learning method, it makes use of the information of continuous dependent variables to distinguish intrinsic neighbourhood and extrinsic neighbourhood of data samples, and construct two graphs according to these two kinds of neighbourhoods. Following the idea of Laplacian eigenmaps, we reveal that on the low-dimensional manifold the neighbourhood structure can be preserved or even improved. Our approach has two important characteristics: (i) it uses dependent variables to find an informative low-dimensional projection which is robust to noisy independent variables and (ii) the objective function simultaneously enlarges the distance between dissimilar samples and pushes similar samples close to each other according to the graph constructed with the help of continuous dependent variables. Our experiments demonstrate that the effectiveness of our method is over their traditional rivals.     

Bayesian density regression for discrete outcomes

We develop Bayesian models for density regression with emphasis on discrete outcomes. The problem of density regression is approached by considering methods for multivariate density estimation of mixed scale variables, and obtaining conditional densities from the multivariate ones. The approach to multivariate mixed scale outcome density estimation that we describe represents discrete variables, either responses or covariates, as discretised versions of continuous latent variables. We present and compare several models for obtaining these thresholds in the challenging context of count data analysis where the response may be over‐ and/or under‐dispersed in some of the regions of the covariate space. We utilise a nonparametric mixture of multivariate Gaussians to model the directly observed and the latent continuous variables. The paper presents a Markov chain Monte Carlo algorithm for posterior sampling, sufficient conditions for weak consistency, and illustrations on density, mean and quantile regression utilising simulated and real datasets.     

Violence in the name of god? A framing processes approach to the Islamic State in Iraq and Syria

Since summer 2014, the insurgent group ‘Islamic State in Iraq and Syria’ (ISIS) has become a major concern for international politics and global security due to its rapid territorial gains, violent operations and the propagation of Salafi-jihadist ideology. This study aims to enhance the academic understanding of ISIS by demystifying the ideological reasoning behind its use of violence. It therefore investigates the link between structural factors that served ISIS’s evolution, its ideological outlook and the significance of this ideology to legitimize violent action. As its theoretical basis, the study employs framing processes within the study of social movements. Methodologically, discursive frame analysis serves to explore the relation of ISIS’s ideology to structural events and experiences to better understand how the group justifies violence. Therefore, the study draws on audio speeches and issues of the magazines Dabiq and Dar al-Islam published by ISIS, which are examined on the rhetoric of othering, collective identity and justifying violence. It is argued that ISIS constructs a collective action frame which creates a social reality that bestows the group with a rationale for action. ISIS’s ideology, based on Islamic symbolism, presents an interpretative lens which assigns meaning to the structural environment of ISIS’s emergence. In this context, violence is justified as a necessity to defend Islam and as an obligation for the true Muslim believer. The discussion concludes that ISIS’s ideology legitimizes the very existence of the group and conceals its mundane struggle for power, territory and wealth through reference to divine authority.     

Maternal Education and Investments in Children's Health

Maternal education differences in children's academic skills have been strongly linked to parental investment behaviors. This study extended this line of research to investigate whether these same maternal education patterns in parenting are observed among a set of parenting behaviors that are linked to young children's health. Drawing on data from the Early Childhood Longitudinal Study, Birth Cohort (n = 5,000) and longitudinal models incorporating random effects, the authors found that higher levels of maternal education were associated with more advantageous health investment behaviors at each phase of early development (9 months, 2 years, 4 years, 5 years). Moreover, these disparities were typically largest at the developmental stage when it was potentially most sensitive for children's long‐term health and development. These findings provide further evidence of a developmental gradient associated with mothers' education and new insight into the salience of mothers' education for the short‐ and long‐term health and well‐being of their children.     

Familism Values,Family Time,and Mexican‐Origin Young Adults' Depressive Symptoms

Using longitudinal data across eight years, this study examined how parents' familism values in early adolescence predicted youths' depressive symptoms in young adulthood via youths' familism values and family time. We examined these processes among 246 Mexican‐origin families using interview and phone‐diary data. Findings revealed that fathers' familism values predicted male and female youths' familism values in middle adolescence. For female youth only, fathers' familism values also predicted youths' family time in late adolescence. The link between family time and young adults' depressive symptoms depended on parental acceptance and adolescent gender: Among female and male youth, family time predicted fewer depressive symptoms, but only when paternal acceptance was high. For female adolescents only, family time predicted fewer depressive symptoms when maternal acceptance was high but more depressive symptoms when maternal acceptance was low. Findings highlight family dynamics as the mechanisms through which familism values have implications for youths' adjustment.     

The Progression of Sexual Relationships

The authors examine factors associated with the advancement or dissolution of newly formed sexual relationships. Data from the 2006–2010 National Survey of Family Growth (NSFG) was used to examine women and men aged 18–39 (n = 2,774) whose most recent sexual relationship began within the 12 months before their interview. Results indicate that newly formed sexual relationships are often transitory. By 12 months, only 23% of respondents remained in nonresidential sexual relationships, another 27% were cohabiting with that partner, and half had ended their relationships. Sexual relationships formed before age 25 are significantly more likely to break up than to transition into cohabitation. Indicators of social class disadvantage, such as living with a stepparent, expedited cohabitation, whereas measures of advantage, such as having a college‐educated mother, deterred transitions into shared living. Racial differences also emerge: Blacks were less likely than Whites to transition rapidly into shared living.     

Socialization Processes and Clergy Offenders

This article uses feminist theory to investigate how the socialization processes used to maintain the clergy community in the Roman Catholic Church contributes to a vulnerability in some clergy for sexually abusing children. This vulnerability is identified first in an examination of the literature on the impact of socialization processes on clergy offenders between the 1960s and 1980s. A comparison is then made with the implications of the apostolic exhortation, Pastores Dabo Vobis, which provides a theological basis to clergy formation. The article argues that the document works to ensure a continuity of socialization processes that not only have been shown to create a vulnerability for committing child sexual abuse but compound existing vulnerabilities. The article concludes that constraints produced by the preservation of a hegemonic masculinity and patriarchy retain a threat of violence against children and require recommended reforms.