Copula based flexible modeling of associations between clustered event times

Multivariate survival data are characterized by the presence of correlation between event times within the same cluster. First, we build multi-dimensional copulas with flexible and possibly symmetric dependence structures for such data. In particular, clustered right-censored survival data are modeled using mixtures of max-infinitely divisible bivariate copulas. Second, these copulas are fit by a likelihood approach where the vast amount of copula derivatives present in the likelihood is approximated by finite differences. Third, we formulate conditions for clustered right-censored survival data under which an information criterion for model selection is either weakly consistent or consistent. Several of the familiar selection criteria are included. A set of four-dimensional data on time-to-mastitis is used to demonstrate the developed methodology.     

Multivariate mixtures of Erlangs for density estimation under censoring

Multivariate mixtures of Erlang distributions form a versatile, yet analytically tractable, class of distributions making them suitable for multivariate density estimation. We present a flexible and effective fitting procedure for multivariate mixtures of Erlangs, which iteratively uses the EM algorithm, by introducing a computationally efficient initialization and adjustment strategy for the shape parameter vectors. We furthermore extend the EM algorithm for multivariate mixtures of Erlangs to be able to deal with randomly censored and fixed truncated data. The effectiveness of the proposed algorithm is demonstrated on simulated as well as real data sets.     

Copula directed acyclic graphs

A new methodology for selecting a Bayesian network for continuous data outside the widely used class of multivariate normal distributions is developed. The ‘copula DAGs’ combine directed acyclic graphs and their associated probability models with copula C/D-vines. Bivariate copula densities introduce flexibility in the joint distributions of pairs of nodes in the network. An information criterion is studied for graph selection tailored to the joint modeling of data based on graphs and copulas. Examples and simulation studies show the flexibility and properties of the method.     

Testing for lack of fit in inverse regression—with applications to biophotonic imaging

Summary.  We propose two test statistics for use in inverse regression problems Y = K θ + ɛ , where K is a given linear operator which cannot be continuously inverted. Thus, only noisy, indirect observations Y for the function θ are available. Both test statistics have a counterpart in classical hypothesis testing, where they are called the order selection test and the data-driven Neyman smooth test. We also introduce two model selection criteria which extend the classical Akaike information criterion and Bayes information criterion to inverse regression problems. In a simulation study we show that the inverse order selection and Neyman smooth tests outperform their direct counterparts in many cases. The theory is motivated by data arising in confocal fluorescence microscopy. Here, images are observed with blurring, modelled as convolution, and stochastic error at subsequent times. The aim is then to reduce the signal-to-noise ratio by averaging over the distinct images. In this context it is relevant to decide whether the images are still equal, or have changed by outside influences such as moving of the object table.     

Hemisphericity: Implications of research on clinical practice

A brief history of the research, findings, and conclusions on how our two cortical hemispheres function is given as are some current speculations regarding an anatomical locus for some psychological phenomena. The paper suggests that much of therapy favors the left hemispheric or sequential mode of thinking. Many therapists may not recognize in some of their clients' responses a right hemispheric or simultaneous thinking preference. Respect for such thinking as on the same intellectual and maturational level as the sequential mode is indicated. Furthermore, techniques to help such clients through the utilization of their preferred hemisphere and through fostering hemispheric cross-talk can be devised. Three cases of such clients and the techniques used in working with them are described.     

Techno economic systems and excessive consumption: a political economy of ‘pathological’ gambling

This article argues that gambling is a paradigmatic form of consumption that captures the intensified logic at the heart of late modern capitalist societies. As well as a site of intensified consumption, it claims that gambling has also become the location of what has been described as a new form of ‘social pathology’ related to excess play. Drawing on Castells' (1996) notion of techno‐economic systems, it explores the ways that intersections between technology, capital and states have generated the conditions for this situation, and critiques the unequal distribution of gambling environments that result. It argues that, while the products of these systems are consumed on a global scale, the risks associated with them tend to be articulated in bio‐psychological discourses of ‘pathology’ which are typical of certain types of knowledge that have salience in neo‐liberal societies, and which work to conceal wider structural relationships. We argue that a deeper understanding of the political and cultural economy of gambling environments is necessary, and provide a synoptic overview of the conditions upon which gambling expansion is based. This perspective highlights parallels with the wider global economy of finance capital, as well as the significance of intensified consumption, of which gambling is an exemplary instance. It also reveals the existence of a geo‐political dispersal of ‘harms’, conceived as deteriorations of financial, temporal and social relationships, which disproportionately affect vulnerable social groups. From this, we urge an understanding of commercial gambling based on a critique of the wider social body of gambling environments within techno economic systems, rather than the (flawed) individual bodies within them.     

Vertical Village: Social Contacts in a Singles Highrise Complex

Abstract

This paper examines the characteristics of community life in a age-segregated highrise complex and the implications of this new form of housing for the quality of urban life. The physical characteristics of the housing do not determine behavior of occupants, but use of the residential environment is shaped by the image of the community and is also affected by the characteristics of residents and their housing expectations. The reputation of the community serves to attract a certain type of person—the upper middle class, well-educated, and single young adult—in high concentrations.

Despite previous studies which have characterized young adults in city neighborhoods as totally cut off from local ties, a combination of factors encourages a high degree of neighboring among this population: homogeneity in terms of age, class, ethnicity, and stage of the life cycle: social selectivity of persons with a positive interest in neighboring: a high concentration of persons occupying a deviant social status; and inter-locking networks of friendship, work and organizational ties. “Marginals” in this environment are the small minority of older and married tenants who compensate for their deviant status vis a vis the majority group of young singles by over-selecting other tenants like themselves for nieghboring relations.     

On gambling research,social science and the consequences of commercial gambling

Social, political, economic, geographic and cultural processes related to the significant growth of the gambling industries have, in recent years, been the subject of a growing body of research. This body of research has highlighted relationships between social class and gambling expenditure, as well as the design, marketing and location of gambling products and businesses. It has also demonstrated the regressive nature of much gambling revenue, illuminating the influence that large gambling businesses have had on government policy and on researchers, including research priorities, agendas and outcomes. Recently, critics have contended that although such scholarship has produced important insights about the operations and effects of gambling businesses, it is ideologically motivated and lacks scientific rigour. This response explains some basic theoretical and disciplinary concepts that such critique misunderstands, and argues for the value of social, political, economic, geographic and cultural perspectives to the broader, interdisciplinary field of gambling research.     

Empirical likelihood confidence regions for comparison distributions and roc curves

Abstract: The authors derive empirical likelihood confidence regions for the comparison distribution of two populations whose distributions are to be tested for equality using random samples. Another application they consider is to ROC curves, which are used to compare measurements of a diagnostic test from two populations. The authors investigate the smoothed empirical likelihood method for estimation in this context, and empirical likelihood based confidence intervals are obtained by means of the Wilks theorem. A bootstrap approach allows for the construction of confidence bands. The method is illustrated with data analysis and a simulation study.