Bayesian analysis of a marked point process: Application in seismic hazard assessment

Point processes are the stochastic models most suitable for describing physical phenomena that appear at irregularly spaced times, such as the earthquakes. These processes are uniquely characterized by their conditional intensity, that is, by the probability that an event will occur in the infinitesimal interval (t, t+Δt), given the history of the process up tot. The seismic phenomenon displays different behaviours on different time and size scales; in particular, the occurrence of destructive shocks over some centuries in a seismogenic region may be explained by the elastic rebound theory. This theory has inspired the so-called stress release models: their conditional intensity translates the idea that an earthquake produces a sudden decrease in the amount of strain accumulated gradually over time along a fault, and the subsequent event occurs when the stress exceeds the strength of the medium. This study has a double objective: the formulation of these models in the Bayesian framework, and the assignment to each event of a mark, that is its magnitude, modelled through a distribution that depends at timet on the stress level accumulated up to that instant. The resulting parameter space is constrained and dependent on the data, complicating Bayesian computation and analysis. We have resorted to Monte Carlo methods to solve these problems.     

A Bayesian Analysis for Accelerated Lifetime Tests Under an Exponential Power Law Model with Threshold Stress

In this paper, we present a Bayesian methodology for modelling accelerated lifetime tests under a stress response relationship with a threshold stress. Both Laplace and MCMC methods are considered. The methodology is described in detail for the case when an exponential distribution is assumed to express the behaviour of lifetimes, and a power law model with a threshold stress is assumed as the stress response relationship. We assume vague but proper priors for the parameters of interest. The methodology is illustrated by a accelerated failure test on an electrical insulation film.     

Stress at work and psychological and immunological parameters in a group of Norwegian female bank employees

This study concerned the immunological correlates of stress and work. Self reported stress, emotional state, ego-strength, and defensiveness were examined in relation to measures of cellular immunity (T-cell response to Con A and number of T4 and T8 cells) and humoral immunity (concentrations of immunoglobulins and complement components in plasma) in a group of 96 Norwegian female bank employees. The analyses showed that workload, the stress factor with the highest group mean, was associated with number of T-cells, while strain due to body posture during work was related to concentrations of IgM and C3. Further, depression was significantly correlated with IgM concentration and T-cell number, and anxiety with C3 concentration. T-cell activity was the immunological parameter most consistently associated with psychological well-being, showing positive correlations with defensiveness and ego-strength and negative correlations with anxiety and depression. In conclusion, T-cell number and concentrations of IgM and C3 were sensitive to both work-related stress experience and emotional distress. Coping abilities, indicated by the MMPI Ego-strength scale and emotional distress, were reflected in T-cell activity; insufficient coping was associated with low T-cell activity.     

和谐语境中的司法期待

法律关系是人际关系的特殊表现,当事人之间纠纷的发生导致了人际关系的破坏,法律的正义观应关注未来的人际关系。现实中被设计出来作为化解冲突、实现和谐的司法制度,却往往在实际的案件裁判中更多的成为延续和引发再次冲突的根源。因此,司法必须通过裁判使当事人从内心消除怨恨,实现人际关系的修复,而不是仅仅着眼于一个具体个案的审结。简单的追求效率不是以人为本的司法,也不符合转型社会的实际需要。     

Reliability of stress–strength model for exponentiated Pareto distributions

In this paper, the reliability of a system is discussed when the strength of the system and the stress imposed on it are independent, non-identical exponentiated Pareto distributed random variables. Different point estimations and interval estimations are proposed. The point estimators obtained are maximum likelihood, uniformly minimum variance unbiased and Bayesian estimators. The interval estimations obtained are approximate, exact, bootstrap-p and bootstrap-t confidence intervals and Bayesian credible interval. Different methods and the corresponding confidence intervals are compared using Monte-carlo simulations.     

Allocation of resources in asymmetric competitions: How do the weak maintain a chance of winning?

To maintain a chance of occasionally beating a stronger player in a competition waged over several fields, a weaker player should give up on some of the fields and concentrate resources on the remaining ones. But when do weak players actually do this? And which fields do they give up when the fields differ in their likelihood of being assessed? We report an experimental study of resource allocation in which asymmetric pairs of players compete over asymmetric fields. Symmetric players and symmetric fields are used for control. We find that players behave as follows: (1) Average wins are the same in the symmetric and asymmetric fields conditions and correspond to relative player strength. (2) The proportion of fields given up on decreases with a player’s greater relative strength, increases for asymmetric field likelihoods, and increases when competitions are framed in meaningful context; this proportion is related to wins. (3) When field likelihoods are asymmetric, players’ resource allocation is correlated with likelihood. Wins generally increase with that correlation but the relation is different for players of different strength. (4) The proportion of fields given up on and the correlation with likelihood change with experience towards the values corresponding to higher wins.     

Support for midwives – A model of professional supervision based on the recertification programme for midwives in New Zealand

Following a traumatic practice experience the physiological and psychological effects experienced by midwives are exacerbated as a result of dysfunctional health organisations and the counterproductive behaviours therein. It is suggested the stress experienced would have been reduced if support in the form of professional supervision had been available.The aim of this article is to demonstrate that professional supervision should be viewed as a competency requirement by the Midwifery Council of New Zealand and incorporated into the midwifery recertification programme. A model of professional supervision for midwives based on the recertification programme is introduced and the importance of reflection on practice emphasised. Providing support by means of professional supervision in the midwifery recertification programme, has the potential to make midwives feel valued, improve their job satisfaction, reduce violence in the workplace, aid in the attrition rate and improve the care for the childbearing woman.     

Deactivating the Buttons: Integrating Radical Exposure Tapping with a Family Therapy Framework

The purpose of this paper is to describe and illustrate with case examples a brief intervention termed Radical Exposure Tapping (RET). RET can be integrated with family therapy to address stuck points where the therapy is hindered by a family member's affective block, an intense and unchangeable emotional reactivity to a specific trigger. RET draws from the methodology of Eye Movement Desensitization and Reprocessing (EMDR) and combines it with the tapping sequence of the Emotional Freedom Technique (EFT) to produce an intervention that is more flexible than EMDR, provides greater rigor than using the EFT technique alone and can be effective in a single session within the context of family therapy. The paper puts this work into context by first over viewing definitions of trauma and Post‐Traumatic Stress Disorder, arguing that family members' emotional reactivity may be a symptom of PTSD even when they would not qualify for the diagnosis because they had not experienced a life threatening event.     

The burdens of social capital: How socially-involved people dealt with stress after Hurricane Katrina

Research shows that those with greater social capital enjoy better physical and mental health. The current study illuminates a paradox of social capital which may afflict those involved in traumatic events. Several years of survey data reveal a dynamic picture of the link between social capital and stress following Hurricane Katrina. Results reveal that initially after Katrina, those who were more socially embedded carried the greatest load with respect to helping the displaced population, thus experiencing more stress. But over time, the most socially-involved then snapped back from their stressful experiences more rapidly than isolates. This confirms that over the course of stressful events, social involvement first exposes people to more stress, but as time passes, provides them a significant buffer against negative psychosocial experiences.     

Comparison of Interval Estimators of Pr(X < Y) in the Two-parameter Exponential Distribution

We consider confidence intervals for the stress–strength reliability Pr(X< Y) in the two-parameter exponential distribution. We have derived the Bayesian highest posterior density interval using non-informative prior distributions. We have compared its performance with the intervals based on the generalized pivot variable intervals in terms of their coverage probabilities and expected lengths. Our simulation study shows that the Bayesian interval performs better according to the criteria used, especially when the sample sizes are very small. An example is given.