Bayesian bivariate survival analysis using the power variance function copula

Copula models have become increasingly popular for modelling the dependence structure in multivariate survival data. The two-parameter Archimedean family of Power Variance Function (PVF) copulas includes the Clayton, Positive Stable (Gumbel) and Inverse Gaussian copulas as special or limiting cases, thus offers a unified approach to fitting these important copulas. Two-stage frequentist procedures for estimating the marginal distributions and the PVF copula have been suggested by Andersen (Lifetime Data Anal 11:333–350, 2005), Massonnet et al. (J Stat Plann Inference 139(11):3865–3877, 2009) and Prenen et al. (J R Stat Soc Ser B 79(2):483–505, 2017) which first estimate the marginal distributions and conditional on these in a second step to estimate the PVF copula parameters. Here we explore an one-stage Bayesian approach that simultaneously estimates the marginal and the PVF copula parameters. For the marginal distributions, we consider both parametric as well as semiparametric models. We propose a new method to simulate uniform pairs with PVF dependence structure based on conditional sampling for copulas and on numerical approximation to solve a target equation. In a simulation study, small sample properties of the Bayesian estimators are explored. We illustrate the usefulness of the methodology using data on times to appendectomy for adult twins in the Australian NH&MRC Twin registry. Parameters of the marginal distributions and the PVF copula are simultaneously estimated in a parametric as well as a semiparametric approach where the marginal distributions are modelled using Weibull and piecewise exponential distributions, respectively.     

Rationality on the rise: Why relative risk aversion increases with stake size

How does risk tolerance vary with stake size? This important question cannot be adequately answered if framing effects, nonlinear probability weighting, and heterogeneity of preference types are neglected. We show that the observed increase in relative risk aversion over gains cannot be captured by the curvature of the value function. Rather, it is predominantly driven by a change in probability weighting of a majority group of individuals who weight probabilities of high gains more conservatively. Contrary to gains, no coherent change in relative risk aversion is observed for losses. These results not only challenge expected utility theory, but also prospect theory.     

Overtime in Relation to Blood Pressure and Mood During Work, Leisure, and Night Time

This study examined the association between characteristics of the workplace and overtime. A sample of 117 women and 126 men were assessed over 24 hours of a working day by means of a computerized diary and ambulant monitoring of blood pressure. Of the total sample, 178 participants had a contractual weekly working time of 40 hours. Of these, 106 participants worked overtime (OT) and 72 worked regular time (RT). Contrary to expectations, a significant association was found between the amount of OT and the quality of task design (e.g., high decision latitude, high level of freedom). Men and women working OT had less leisure time, and men also reported less obligatory time (e.g., time for household, childcare etc.) than those working RT. Women, but not men, working OT had a higher systolic and diastolic blood pressure during work than those working RT. Significantly more participants in the group of men and women working OT were found to have a disturbed ability to recover and to display clinically relevant sleep disturbances than in the group working regular hours. Furthermore, working OT was associated with less positive affect after work (obligatory and leisure time) in men, and with more negative affect during work and before going to bed in men and women. The results imply the need for jobs that can be finished within regular working hours and that give employees opportunities for job control. Such jobs enable a balance to be found between work load and recovery and represent a prerequisite for occupational health and well-being.     

Philanthropy in 18th-Century Central Europe: Evangelical Reform and Commerce

This article focuses on the close linkage between domestic philanthropy and commerce at the end of the early modern period, and the sophistication with which well-connected evangelical institutions transcended the confines of established religion and territorial boundaries. Use of a large set of primary and secondary sources that are relatively unknown in the history of the voluntary sector permits the examination and analysis of several notable aspects of the Francke Orphanage Foundations, an 18th-century central European institution of evangelical reform and colonial mission. Particular attention is given to the innovative efforts of their founder, August Hermann Francke, to secure an independent financial base for his institutional goals. These goals, which were supported in large part by members of the German nobility and of merchants in the imperial cities, included but were not limited to reform of charity care and education. From the outset, a close network of personal supporters and evangelical institutions that extended throughout Protestant Europe proved essential for both trade and evangelical mission; this network permitted expansion into Russia and the Baltic provinces, Hungary, the Near East and India, and eventually the British North American colonies.     

Solidarität

Which socio-psychological terms are connected with the term “solidarity”? Solidarity is understood as a specific attitude and quality of relationships between individuals in groups and organizations and on the level of society. A disturbed balance between “self-enhancement” and “self-transcendence” caused by socio-cultural developments diminishes solidarity. The questions that are considered and discussed, are the following: Under which conditions does solidarity arise, which conditions in groups allow individuals to learn about solidarity, do current organizational structures affect the well tried forms of organized solidarity and how does empowerment conflict with the balance of power in society?     

The association between blood pressure and work stress: The importance of measuring isolated systolic hypertension

The objective was to study whether the relationships between elevated blood pressure and (a) work stress as related to the stressor overtime, and (b) unwinding after work, depend on what kind of criteria are used for the diagnosis of hypertension. A total of 126 healthy men (aged 20-66 years) employed in white-collar jobs were tested over 24 hours by means of ambulatory blood pressure monitoring on a regular working day. Four groups were defined according to their blood pressure status: normotensives (NT), hypertensives (HT), isolated systolic hypertensives (ISH), and isolated diastolic hypertensives (IDH). No differences of age, body mass index, overtime work, and disturbed unwinding were found between the normotensives and the hypertensives. ISH was found to be related to working overtime and to disturbed unwinding but not to biological risk factors; IDH, however, was related exclusively to the biological risk factor high body mass index. Thus, significant differences associated with overtime were found between ISH and both NT and IDH, with the isolated systolic hypertensives carrying out more than twice as much overtime as the normotensives or isolated diastolic hypertensives. More men with a disturbed ability to relax and vital exhaustion were found in the ISH group than in the NT group. It seems that, in addition to the usual diagnosis of hypertension, the classification of ISH and IDH adds new information about the relationship between blood pressure elevation and both work stress and disturbed unwinding.     

The Effect of Father–Toddler and Mother– Toddler Role Reversal on the Development of Behavior Problems in Kindergarten

Role reversal is a relationship disturbance in which a parent looks to a child to meet a parent's need for comfort, parenting, intimacy or play, and the child attempts to meet these needs. The current study examined, within a developmental psychopathology framework, the effect of father and mother role reversal with toddlers on the development of attention problems, externalizing symptoms, internalizing symptoms, and social problems in kindergarten. In a normative sample, N=57, role reversal was assessed in an observational paradigm, and teachers rated behavior problems. Father role reversal predicted attention problems and externalizing symptoms, whereas mother role reversal predicted social problems. Gender was an important moderator such that father role reversal predicted social problems for boys and mother role reversal predicted social problems for girls. The importance of a developmental psychopathology perspective, the role of fathers, and implications for the development of diagnosable disorders and for preventive interventions are discussed.     

Sektionen Jugendsoziologie und Kultursoziologie

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