A structured Dirichlet mixture model for compositional data: inferential and applicative issues

The flexible Dirichlet (FD) distribution (Ongaro and Migliorati in J. Multvar. Anal. 114: 412–426, 2013) makes it possible to preserve many theoretical properties of the Dirichlet one, without inheriting its lack of flexibility in modeling the various independence concepts appropriate for compositional data, i.e. data representing vectors of proportions. In this paper we tackle the potential of the FD from an inferential and applicative viewpoint. In this regard, the key feature appears to be the special structure defining its Dirichlet mixture representation. This structure determines a simple and clearly interpretable differentiation among mixture components which can capture the main features of a large variety of data sets. Furthermore, it allows a substantially greater flexibility than the Dirichlet, including both unimodality and a varying number of modes. Very importantly, this increased flexibility is obtained without sharing many of the inferential difficulties typical of general mixtures. Indeed, the FD displays the identifiability and likelihood behavior proper to common (non-mixture) models. Moreover, thanks to a novel non random initialization based on the special FD mixture structure, an efficient and sound estimation procedure can be devised which suitably combines EM-types algorithms. Reliable complete-data likelihood-based estimators for standard errors can be provided as well.     

Intergenerational Care Perceptions of Older Women and Middle Adolescents in a Resource-Constrained Community in South Africa

ABSTRACT

This study describes intergenerational care perceptions in a resource-challenged community. Ten women (aged 60+) and eight middle adolescents (3 boys and 5 girls) participated in the Mmogo-method®, a visual data-collection method. Textual data were analysed thematically, and visual data by applying Roos and Redelinghuys (2016) proposed steps. Both groups provided physical and instrumental care to the other. Older women cared for adolescents by teaching and disciplining them, while the adolescents cared for them by obtaining an education and by showing respect. Older women felt being cared for when adolescents helped them, obeyed and complied with instructions and discipline, while the youngsters expressed it when their basic needs were addressed and school attendance was enabled. Older women’s expressions of caring about were vague, while the younger people detected, act and elicited reactions from the elders. The adopted care approach informed care perceptions. Joint intergenerational activities are proposed to discover care currencies and contributions of generational members.     

Influence of Perceived Maternal Psychological Control on Academic Performance in Chinese Adolescents: Moderating Roles of Adolescents’ Age,Gender, and Filial Piety

Existing studies with East Asian samples have reported inconsistent findings on the association between parental psychological control and academic performance in children and adolescents. A moderation effect is present, when the magnitude or direction of the association between two variables significantly changes with another variable called a moderator. This study explored moderators for the association between maternal psychological control and academic performance. A total of 338 Chinese secondary school students aged 14–20completed self-report measures of perceived maternal psychological control, academic performance, and attitudes toward filial piety. Structural equation modeling suggested that adolescent age moderated the association of interest: the influence of perceived maternal psychological control on academic performance significantly varied between middle adolescents aged 14–17 and late adolescents aged 18–20. Based on the findings, this study offers a possible rationale for the inconsistent findings in studies with East Asian samples and proposes that parenting effect should be assessed developmentally.     

Religion and Value Systems

Uncovering the complex relationships between religiosity and values may provide a better understanding of what it means to be religious or nonreligious. This article reviews research on values and religiosity across cultural and religious groups. Although religious groups differ in the importance they attribute to different values, the pattern of correlations between religiosity and values is strikingly consistent across monotheistic religions: Persons more committed to religion attribute relatively high importance to values expressing motivation to avoid uncertainty and change and relatively low importance to values expressing motivations to follow one's hedonistic desires, or to be independent in thought and action.     

Community e-gateways: locating networks and learning for social inclusion

The provision of community e-gateways (community-based facilities providing public access to computers and the Internet) has been seen as a way to address the 'digital divide', particularly for people from deprived neighbourhoods. In the UK, policy and practitioner literature has stressed that for these centres to be successful they need to have strong social connections and be able to provide opportunities for interactive learning and content creation. Through a detailed analysis of one community e-gateway, which formed part of a wider study of public access provision, this article analyses the strengths and weaknesses of this advice drawing on broader sociological literature relating to social networks, network mapping and communities of practice. It concludes that greater attention needs to be paid to the significance of weak ties, two-way boundary spanning and the resource requirements of social networks for the policy objectives to be fully achieved.     

Promoting youth purpose: a review of the literature

This article reviews the research literature on teaching and supporting purpose in adolescence and young adulthood. An extensive search revealed that most studies on youth purpose examine psychological correlates and neglect instructional and social supports. School is an effective context for fostering purpose, yet reported approaches for explicitly instructing for purpose are rare after the early 1990s, reflecting a trend away from a language of purpose as a discrete endeavor in education since at least the 1960s. Furthermore, research on the outcomes of early purpose instruction curricula is not present in empirical journal articles. Nevertheless, a concern for fostering youth purpose has not disappeared from education; rather, it is subsumed under approaches that foster more comprehensive positive student outcomes, such as character, civic engagement, and positive youth development. Key curricular approaches to these outcomes are therefore also reviewed and examined for insights into how purpose can be fostered.     

Effects of various types of change in shift schedules: A controlled longitudinal study

Data from a longitudinal study accompanying changes in shift rotas connected with a shortening of working time in the chemical industry are presented. Altogether 260 subjects forming five experimental groups participated in both the pretest and the posttest. The effects of the change in shift schedules were controlled by the inclusion of five groups in which 139 subjects participated in both tests. Five types of change in shift schedule were investigated. The purpose was to determine to what extent similar, but in some aspects differing, types of change in shift schedule varied from one another in their effects on those involved, and on which factors their attitudes towards the new shift systems depended with regard to various types of schedule change. The effects of a change in shift schedule were tested by means of the 4-group investigation design developed by Solomon (1949). The results confirm that differences in the effects of new shift systems depend on the type of change. Only in three experimental groups were improvements in health and social life observed. One experimental group showed significant signs of deterioration in subjective health. In the analyses of the factors influencing the attitude of the shiftworkers towards the new shift system, differences in the structure of the influencing factors between the experimental groups were observed. The causal analysis was used in order to test how important the factors found in each group were and which of them were dominant. It showed that the most influential factors dominated so much that the disturbances in the less influential ones lost their importance. In spite of the number of indicators analysed regarding their influence on attitude in this study, further important factors seem to exist that have not been analysed here.     

Sibling death clustering in India: state dependence versus unobserved heterogeneity

Summary.  Data from a range of environments indicate that the incidence of death is not randomly distributed across families but, rather, that there is a clustering of death among siblings. A natural explanation of this would be that there are (observed or unobserved) differences across families, e.g. in genetic frailty, education or living standards. Another hypothesis that is of considerable interest for both theory and policy is that there is a causal process whereby the death of a child influences the risk of death of the succeeding child in the family. Drawing language from the literature on the economics of unemployment, the causal effect is referred to here as state dependence (or scarring). The paper investigates the extent of state dependence in India, distinguishing this from family level risk factors that are common to siblings. It offers some methodological innovations on previous research. Estimates are obtained for each of three Indian states, which exhibit dramatic differences in socio-economic and demographic variables. The results suggest a significant degree of state dependence in each of the three regions. Eliminating scarring, it is estimated, would reduce the incidence of infant mortality (among children who are born after the first child) by 9.8% in the state of Uttar Pradesh, 6.0% in West Bengal and 5.9% in Kerala.     

'Your friends don't understand': Invisibility and unmet need in the lives of 'young carers'

This paper is based on a study of the experiences of people identified as ‘young carers’, commissioned by the National Assembly for Wales as part of a wider review of carers’ needs and services. Following a brief review of some of the previous research in this area, the paper reports key findings of the research, using the words of children and young people as much as possible. It then goes on to explore some of the wider implications of this and other research for the identification and support of ‘young carers’ and their families, and for the understanding of the needs and wishes of children and young people so defined. The paper concludes with an alternative definition of a ‘young carer’ and with some recommendations for professional practice, suggesting that the role of social work is crucial in this area of service.