Identifiable finite mixtures of location models for clustering mixed-mode data

For clustering mixed categorical and continuous data, Lawrence and Krzanowski (1996) proposed a finite mixture model in which component densities conform to the location model. In the graphical models literature the location model is known as the homogeneous Conditional Gaussian model. In this paper it is shown that their model is not identifiable without imposing additional restrictions. Specifically, for g groups and m locations, (g!)m–1 distinct sets of parameter values (not including permutations of the group mixing parameters) produce the same likelihood function. Excessive shrinkage of parameter estimates in a simulation experiment reported by Lawrence and Krzanowski (1996) is shown to be an artifact of the model's non-identifiability. Identifiable finite mixture models can be obtained by imposing restrictions on the conditional means of the continuous variables. These new identified models are assessed in simulation experiments. The conditional mean structure of the continuous variables in the restricted location mixture models is similar to that in the underlying variable mixture models proposed by Everitt (1988), but the restricted location mixture models are more computationally tractable.     

Bootstrapping data with multiple levels of variation

The authors consider general estimators for the mean and variance parameters in the random effect model and in the transformation model for data with multiple levels of variation. They show that these estimators have different distributions under the two models unless all the variables have Gaussian distributions. They investigate the asymptotic properties of bootstrap procedures designed for the two models. They also report simulation results and illustrate the bootstraps using data on red spruce trees.     

Improving early phase oncology clinical trial design: The case for finding the optimal biological dose

Historically early phase oncology drug development programmes have been based on the belief that “more is better”. Furthermore, rule-based study designs such as the “3 + 3” design are still often used to identify the MTD. Phillips and Clark argue that newer Bayesian model-assisted designs such as the BOIN design should become the go to designs for statisticians for MTD finding. This short communication goes one stage further and argues that Bayesian model-assisted designs such as the BOIN12 which balances risk-benefit should be included as one of the go to designs for early phase oncology trials, depending on the study objectives. Identifying the optimal biological dose for future research for many modern targeted drugs, immunotherapies, cell therapies and vaccine therapies can save significant time and resources.     

Queer-friendly nation? The experience of Chinese gay immigrants in Canada

In the past decade, the People’s Republic of China has become the leading source country of immigrants to Canada. However, little is known about the experience of Chinese gay immigrants in Canada. Using narratives collected through a qualitative study, we show the way in which Chinese gay men construct their experience of immigration in Canada. Unlike the national discourse that claims Canada is a friendly nation for members of the LGBTTQ community, the experiences of Chinese gay immigration present a different story. As racialised gay men, they continue to be subjected to social violence in Canada – albeit differently from what they experienced in China. The analysis demonstrates the complexity of social marginalisation experienced by these men, the understanding of which is essential for social workers to engage in practice with them that is socially transformative.     

The Disneyization of Society

This article proposes the idea of Disneyization as a complementary notion to McDonaldization. Disneyization is depicted as a process by which the principles of the Disney theme parks dominate more and more sectors of society. It is presented as comprising four aspects: theming, dedifferentiation of consumption, merchandising, and emotional labour. The empirical manifestations of these attributes are outlined. The roots of Disneyization in theories of consumerism and consumer culture are examined and are contrasted with the grounding of McDonaldization in the idea of rationalization. Some of the theoretical implications of the contrasts between Disneyization and McDonaldization are presented.     

Dimensions of Family Conflict and Their Influence on Child and Adolescent Adjustment

Using the first (1987-1988) and second (1992-1994) waves of the National Survey of Families and Households, this study examines the concurrent and longitudinal influences of interparental conflict and parent-child conflict on child and adolescent adjustment. Analyses focus on 542 intact families, each with a randomly selected focal child aged 5 to 11 at time 1 and aged 10 to 17 at time 2. Results indicate that both parent-child and parent-adolescent conflict are critical predictors of children's and adolescents'socioemotional adjustment. Interparental conflict, by contrast, is less important for adjustment in middle and late childhood as well as in adolescence. The findings extend previous research by suggesting that the salience and threat of interparental conflict subside as children make the transition into adolescence.     

Gambling Among Prison Inmates: Patterns and Implications

There is an absence of research on gambling among prison inmates during their incarceration. Little is known about how prisoners organize gambling activities or the potential risks they face from gambling. Similarly, no empirical attention has been given to how correctional institutions respond to inmate gambling. This study employed interviews with 55 male prisoners and self-administered surveys with 159 correctional officers and staff, at two medium security prisons in Ohio. Data were gathered on prevalence and patterns of inmate gambling, perceived hazards of gambling, and perceived institutional responses to prisoner gambling. Findings suggest that inmate gambling is common and constitutes an important feature of the underground economy of prisons, yet little is done to deter or prevent this activity. Suggestions are made for more effective institutional responses.