Localisation and ageing in the parabolic Anderson model with Weibull potential

The parabolic Anderson model is the Cauchy problem for the heat equation on the integer lattice with a random potential $\xi$. We consider the case when $\{\xi(z):z\in\mathbb{Z}^d\}$ is a collection of independent identically distributed random variables with Weibull distribution with parameter $0<\gamma<2$, and we assume that the solution is initially localised in the origin. We prove that, as time goes to infinity, the solution completely localises at just one point with high probability, and we identify the asymptotic behaviour of the localisation site. We also show that the intervals between the times when the solution relocalises from one site to another increase linearly over time, a phenomenon known as ageing.Comment: Published in at http://dx.doi.org/10.1214/13-AOP882 the Annals of Probability (http://www.imstat.org/aop/) by the Institute of Mathematical Statistics (http://www.imstat.org

The association between affective temperaments and depressive symptoms in a population of medical university students, Poland

BackgroundCompared to their peers, medical students are more exposed to stress, and many present symptoms of depression, making them a group prone to experiencing mental illnesses.ObjectiveThis study investigates a potential link between the occurrence of symptoms of depression and the dominating type of affective temperament in young people studying at a medical university.MethodsOne hundred thirty-four medical students were surveyed using two validated questionnaires; the Polish versions of Beck’s Depression Inventory-II (BDI-II) and the Temperament Evaluation of the Memphis, Pisa, and San Diego Autoquestionnaire (TEMPS-A).ResultsThe data analysis revealed a significant link between symptoms of depression and affective temperaments, most significantly in subjects with an anxious temperament.ConclusionThis study confirms the role of various affective temperaments as a risk factor for mood disorders, specifically depression