A Semi-parametric Bayesian Analysis of Survival Data Based on Lévy-driven Processes

In the presence of covariate information, the proportional hazards model is one of the most popular models. In this paper, in a Bayesian nonparametric framework, we use a Markov (Lévy-driven) process to model the baseline hazard rate. Previous Bayesian nonparametric models have been based on neutral to the right processes, which have a number of drawbacks, such as discreteness of the cumulative hazard function. We allow the covariates to be time dependent functions and develop a full posterior analysis via substitution sampling. A detailed illustration is presented.     

Markov Chain Monte Carlo in small worlds

As the number of applications for Markov Chain Monte Carlo (MCMC) grows, the power of these methods as well as their shortcomings become more apparent. While MCMC yields an almost automatic way to sample a space according to some distribution, its implementations often fall short of this task as they may lead to chains which converge too slowly or get trapped within one mode of a multi-modal space. Moreover, it may be difficult to determine if a chain is only sampling a certain area of the space or if it has indeed reached stationarity. In this paper, we show how a simple modification of the proposal mechanism results in faster convergence of the chain and helps to circumvent the problems described above. This mechanism, which is based on an idea from the field of “small-world” networks, amounts to adding occasional “wild” proposals to any local proposal scheme. We demonstrate through both theory and extensive simulations, that these new proposal distributions can greatly outperform the traditional local proposals when it comes to exploring complex heterogenous spaces and multi-modal distributions. Our method can easily be applied to most, if not all, problems involving MCMC and unlike many other remedies which improve the performance of MCMC it preserves the simplicity of the underlying algorithm.     

Corporate Reputation and Women on the Board

In this paper, we investigate the determinants of corporate reputation, derived from the assessments of managers and market analysts, of a sample of large UK firms. Along with the influences of a variety of firm attributes, we find a reputational effect associated with a female presence at board level. This effect varies across sectors and demonstrates the influence of a firm's stakeholder environment in determining whether a female presence on the board enhances or harms the reputation of the firm. The pattern that emerges indicates that the presence of women on the board is favourably viewed in only those sectors that operate close to final consumers. We argue that the nature of this effect reflects an imperative for equality of representation that highlights the need to reflect gender diversity among customers.     

The Next Generation of Collective Action Research

The articles presented in this volume describe part of a new generation of interest and vigor in the social psychological study of collective action. This new wave builds nicely on the foundation set by social identity, self-categorization, and relative deprivation theories but also introduces a number of important innovative perspectives and variables. In this commentary, I review some of these expansions and additions, raise a number of conceptual concerns that arise out of these new directions, and discuss more generally some novel and important directions that emerge from the work presented in the volume and in other recent work on collective action.     

The politics of figurational sociology

Figurational sociology is so often said to distance itself from the political issues of the day. Whilst this is certainly true with regards to the present day, it in no way follows that figurational sociology seeks to distance itself from politics as such. On the contrary, as will be shown within this paper, politics is and always has been a central concern for figurational sociologists. This political concern, however, is an exclusively long term concern; figurational sociology purposively postpones present political engagement for the sake of developing a sufficiently detached sociology that would eventually facilitate in the delivery of effective practical and political measures. This paper discusses the stakes involved in, as well as the reasoning behind, the assignment of such a place to politics. It gestures towards two distinct and separate concepts of social control that exist within figurational sociology and then proceeds to offer a critical consideration of the consequences that can be derived from any temporal demarcation of the political done on their basis. The paper ultimately suggests that figurational sociology's position on politics raises a series of as yet unanswered questions, questions which can no longer remain unanswered by the contemporary figurational sociologist.     

Transition from school for youths with a disability: issues and challenges

Australian research has demonstrated that students with a disability are more likely to remain out of the full‐time workforce. These research findings have been the catalyst for a call for a comprehensive career development and transition planning approach for all students with disabilities in schools as well as for employers to rethink the role of people with disabilities in the workforce. In the Australian context the transition from school for individuals with a disability is complicated by a disparate and fragmented group of service agencies providing a range of services, including employment, supported accommodation, recreation and leisure pursuits, as well as training and placement, along with, at times, a deep‐seated prejudice towards people with disabilities in the market place. This paper reviews a number of issues and challenges confronting individuals with a disability making the transition from school to the post‐school environment.