Estimation of relative risk for events on a linear network

Motivated by the study of traffic accidents on a road network, we discuss the estimation of the relative risk, the ratio of rates of occurrence of different types of events occurring on a network of lines. Methods developed for two-dimensional spatial point patterns can be adapted to a linear network, but their requirements and performance are very different on a network. Computation is slow and we introduce new techniques to accelerate it. Intensities (occurrence rates) are estimated by kernel smoothing using the heat kernel on the network. The main methodological problem is bandwidth selection. Binary regression methods, such as likelihood cross-validation and least squares cross-validation, perform tolerably well in our simulation experiments, but the Kelsall–Diggle density-ratio cross-validation method does not. We find a theoretical explanation, and propose a modification of the Kelsall–Diggle method which has better performance. The methods are applied to traffic accidents in a regional city, and to protrusions on the dendritic tree of a neuron.

     

Does the Context of Racial Discrimination Matter for Adolescent School Outcomes?: The Impact of In-School Racial Discrimination and General Racial Discrimination on Black Adolescents’ Outcomes

The present study explored the role of context and gender on the association between racial discrimination and adolescents’ outcomes among Black nint     

A lonely society? Loneliness and liquid modernity in Australia

This paper reviews recent studies of loneliness in order to assess whether it is becoming endemic in Australian society. It develops the idea that loneliness is an embedded social structural feature of contemporary Australian life likely to affect people through the life course, creating psychological stress, ill health and social dysfunction. Zygmunt Bauman's writing on liquid modernity is used to trace a sequence of less binding social bonds from the community the workplace, intimate relationships, friendship and kinship that may account for a more generalised distribution of loneliness. Empirical evidence from recent national surveys in Australia demonstrates how Bauman's gloomy prognosis is particularly applicable in Australia. The paper argues that it has been invisible as a social issue until recently, but that its scope and scale have grown such that robust policy initiatives are now warranted. It argues that Australia's gendered pattern of loneliness indicates that Bauman's broad theory of liquid modernity must be mediated by several factors relating to national cultures, historic patterns of family formation, and the gender role distribution in the creation and maintenance of social bonds.     

Modeling uncertainty in macroeconomic growth determinants using Gaussian graphical models

Model uncertainty has become a central focus of policy discussion surrounding the determinants of economic growth. Over 140 regressors have been employed in growth empirics due to the proliferation of several new growth theories in the past two decades. Recently Bayesian model averaging (BMA) has been employed to address model uncertainty and to provide clear policy implications by identifying robust growth determinants. The BMA approaches were, however, limited to linear regression models that abstract from possible dependencies embedded in the covariance structures of growth determinants. The recent empirical growth literature has developed jointness measures to highlight such dependencies. We address model uncertainty and covariate dependencies in a comprehensive Bayesian framework that allows for structural learning in linear regressions and Gaussian graphical models. A common prior specification across the entire comprehensive framework provides consistency. Gaussian graphical models allow for a principled analysis of dependency structures, which allows us to generate a much more parsimonious set of fundamental growth determinants. Our empirics are based on a prominent growth dataset with 41 potential economic factors that has been utilized in numerous previous analyses to account for model uncertainty as well as jointness.     

Organizational discourse as a creative space for play: the potential of postmodernist and surrealist forms of play

In recent times there have been a number of calls in the organizational discourse to consider entertaining the notion of ‘play’. Not overt physical play such as having a game of golf among work mates or team building through rock climbing, but intellectual play. These calls have generally arisen in the work of those scholars championing a postmodernist or post-structuralist perspective. These calls, however, are seldom accompanied by a coherent appraisal of why and how play is productive of something that non-play cannot or has difficulty in producing. In particular, what has been left out of much of this discourse is an appraisal of the underlying psychodynamics that are involved. This paper argues that play takes place in a space created to enhance illusion and that space, and the illusion itself, need careful handling at a variety of levels. Just as the space for play is created for the child to exercise their imagination and as a learning environment, it can equally be the space occupied by the neurotic - indeed, some postmodernists, intent upon play, have been charged with aiding, abetting and creating individuals who become delusional, have fragmented identity and may become schizophrenic. While this latter critique may seem somewhat harsh, it should prompt us to consider the idea of the attributes of a ‘safe’ space in which to play. Much of the organizational discourse on play has also asked us to take play ‘seriously’ as way of enhancing our theory development. This paper does not accept the ‘serious’- ‘non-serious’ dichotomy, but instead argues that play is a differentiated level of reality. This differentiated level of reality is inhabited by much in the way of paradox and irony that are essential for play to occur. These paradoxes and ironies are identified in an effort to enhance the outcome of play. In identifying some of the underlying psychodynamics of play, what emerges is an appreciation of how play is an activity that has the potential to help in our theory development of organizations. In the context of discussing the emergence of a new postmodern theory movement in the organizational discourse, various forms of postmodernist play are identified. In this discussion it will also be noted that these postmodernist forms of play have parallels in other fields. In the realm of art, for example, surrealism engages in similar forms of play. These forms of play are identified in the quest to better understand the dynamics of intellectual play and how we might better draw upon such dynamics to enhance the theoretical grounding of our own field. It is also intended, by examining the notion of intellectual play in a manner outlined in this paper, that basic aspects of postmodernist theorizing might also be better understood.     

A Critical Look at Risk Assessments for Global Catastrophes

Recent articles by Busza et al. (BJSW) and Dar et al. (DDH) argue that astrophysical data can be used to establish small bounds on the risk of a "killer strangelet" catastrophe scenario in the RHIC and ALICE collider experiments. The case for the safety of the experiments set out by BJSW does not rely solely on these bounds, but on theoretical arguments, which BJSW find sufficiently compelling to firmly exclude any possibility of catastrophe. Nonetheless, DDH and other commentators (initially including BJSW) suggested that these empirical bounds alone do give sufficient reassurance. This seems unsupportable when the bounds are expressed in terms of expectation value-a good measure, according to standard risk analysis arguments. For example, DDH's main bound, p(catastrophe) < 2 x 10(-8), implies only that the expectation value of the number of deaths is bounded by 120; BJSW's most conservative bound implies the expectation value of the number of deaths is bounded by 60,000. This article reappraises the DDH and BJSW risk bounds by comparing risk policy in other areas. For example, it is noted that, even if highly risk-tolerant assumptions are made and no value is placed on the lives of future generations, a catastrophe risk no higher than approximately 10(-15) per year would be required for consistency with established policy for radiation hazard risk minimization. Allowing for risk aversion and for future lives, a respectable case can be made for requiring a bound many orders of magnitude smaller. In summary, the costs of small risks of catastrophe have been significantly underestimated by BJSW (initially), by DDH, and by other commentators. Future policy on catastrophe risks would be more rational, and more deserving of public trust, if acceptable risk bounds were generally agreed upon ahead of time and if serious research on whether those bounds could indeed be guaranteed was carried out well in advance of any hypothetically risky experiment, with the relevant debates involving experts with no stake in the experiments under consideration.     

Age discrimination and working life: Perspectives and contestations – a review of the contemporary literature

This review highlights some of the principal issues and debates surrounding age discrimination at the workplace. Essentially, the existing research in this area can be divided into three broad, although somewhat overlapping, categories. The first explores the underlying causes and consequences of age discrimination at the workplace from one or other theoretical tradition. The second broad body of literature encompasses empirical studies which document the nature and extent of age discrimination, based on the use of official statistics, and/or firm‐level survey evidence. The third explores the effects of various governmental initiatives to reduce the incidence of age discrimination and policy options in this area. Even though age discrimination is widely accepted to be prevalent, its causes are rather more contentious. Age discrimination has variously been ascribed to market imperfections, the product of rational choices and the effects of long‐term changes in the nature of the economy. Policy interventions may be prompted by economic pressure, demographic changes or cultural shifts, and have involved voluntary codes as well as legislation. Although voluntary codes have generally proved ineffective, the literature indicates that more formal regulations may still have only limited efficacy, underscoring the deeply rooted nature of age discrimination in society.     

Common factors and our sacred models

In this article we argue that much of what makes one treatment effective is common to other forms of effective treatment--both in psychotherapy generally and in marital and family therapy (MFT) specifically. Yet MFT has largely ignored the research on common factors. In this article we present a moderate view of common factors that, while repudiating the extreme position that there is no difference among treatment models, stresses that there are common factors and mechanisms of change that undergird most forms of successful treatment. These common mechanisms of change should be given more attention in our field, which has tended to emphasize the uniqueness of our sacred models. We delineate some of the major common factors, review the empirical evidence for them, and discuss implications of adapting a common factors informed approach to family therapy.     

A politics that is shared,bounded, and rooted? Rediscovering civic political culture in Western Europe

Theory and Society -