Improved bridge constructs for stochastic differential equations

We consider the task of generating discrete-time realisations of a nonlinear multivariate diffusion process satisfying an Itô stochastic differential equation conditional on an observation taken at a fixed future time-point. Such realisations are typically termed diffusion bridges. Since, in general, no closed form expression exists for the transition densities of the process of interest, a widely adopted solution works with the Euler–Maruyama approximation, by replacing the intractable transition densities with Gaussian approximations. However, the density of the conditioned discrete-time process remains intractable, necessitating the use of computationally intensive methods such as Markov chain Monte Carlo. Designing an efficient proposal mechanism which can be applied to a noisy and partially observed system that exhibits nonlinear dynamics is a challenging problem, and is the focus of this paper. By partitioning the process into two parts, one that accounts for nonlinear dynamics in a deterministic way, and another as a residual stochastic process, we develop a class of novel constructs that bridge the residual process via a linear approximation. In addition, we adapt a recently proposed construct to a partial and noisy observation regime. We compare the performance of each new construct with a number of existing approaches, using three applications.     

The Effects of Corporate Elitism and Groupthink on Organizational Empathy in Crisis Situations

This study is to empirically testify that corporate elitism is an antecedent to groupthink, which prevents organizational empathy from working effectively in crises. The current study is expected to expand the boundary of crisis management literature into a company’s crisis-preparedness before a crisis occurs. The findings offer the useful guidance to organizations on how to better manage their crisis proneness through identifying the early signs of corporate elitism and groupthink.     

German welfare organizations and the process of European integration

The process of European integration affects an increasing number of areas of life. The influence of the European single market on the social sector, including organizations providing human services, can no longer be denied. This article looks at the activities of the European Commission toward these organizations and argues that European regulations are relevant to the German system of social service delivery due to the introduction of market‐like features in the national context. Within this context, German welfare organizations have discovered an important field of interest representation and lobbying.     

Peripubertal Girls' Romantic and Platonic Involvement With Boys: Associations With Body Image and Depression Symptoms

This study explored the relationship of both romantic and platonic involvement with boys, as well as pubertal status, to body image and depression symptoms among an ethnically diverse sample of sixth‐grade girls. Participants were 157 early adolescent girls (ages 10–13) who completed self‐report measures designed to assess girls' level of involvement with boys, pubertal status, and psychological adjustment. Girls' degree of romantic involvement was positively associated with higher depression scores. More advanced pubertal status was associated with both lower body image satisfaction and higher depression scores. A significant interaction between platonic involvement and pubertal status emerged. Girls who were less sexually mature but who also reported more platonic involvement with boys reported greater body image satisfaction. These findings suggest that the type of involvement with boys (romantic vs. platonic) and a girl's pubertal status influence psychological adjustment.