Co-variation between stressful events and rumination predicts depressive symptoms : an eighteen months prospective design in undergraduates

Rumination is a maladaptive form of emotion regulation and seems to be the cognitive mechanism linking stress to depressive symptoms. However, it remains to be investigated whether individuals' variation in rumination in relation to the occurrence of stressful events (e.g., phasic co-variation between stressful events and rumination) prospectively predict the experience of depressive symptoms in lengthy follow-up moments. In this eighteen months prospective design, a large unselected sample of undergraduates was tested before, during, and after a period with prominent naturally occurring stressful events. The multilevel results show that the co-variation of stressful events and ruminative thinking predicts the experience of depressive symptoms at 3 and 15 months follow up moments, also when statistically controlling for baseline depressive symptoms. Moreover, the data demonstrate that the phasic elevations of rumination in relation to the occurrence of stressful events are more predictive of depressive symptoms compared with the stable aspects of rumination measured at one occasion. At the clinical level, the current findings seem to suggest a process-oriented intervention to target the phasic ruminative cognitions where individuals need to learn to control rumination exactly at moments of stress. (C) 2016 Elsevier Ltd. All rights reserved

A driven two-dimensional granular gas with Coulomb friction

We study a homogeneously driven granular gas of inelastic hard particles with rough surfaces subject to Coulomb friction. The stationary state as well as the full dynamic evolution of the translational and rotational granular temperatures are investigated as a function of the three parameters of the friction model. Four levels of approximation to the (velocity-dependent) tangential restitution are introduced and used to calculate translational and rotational temperatures in a mean field theory. When comparing these theoretical results to numerical simulations of a randomly driven mono-layer of particles subject to Coulomb friction, we find that already the simplest model leads to qualitative agreement, but only the full Coulomb friction model is able to reproduce/predict the simulation results quantitatively for all magnitudes of friction. In addition, the theory predicts two relaxation times for the decay to the stationary state. One of them corresponds to the equilibration between the translational and rotational degrees of freedom. The other one, which is slower in most cases, is the inverse of the common relaxation rate of translational and rotational temperatures.Comment: 23 pages, 17 figure

E-Learning: Begriffliche, psychologische und didaktische Überlegungen zum "electronic learning"

Der folgende Beitrag setzt sich kritisch mit dem Begriff des E-Learning in seinen zahlreichen Facetten und Bezugspunkten auseinander und versucht, Möglichkeiten und Grenzen des Einsatzes von E-Learning aufzuzeigen. Im zweiten Teil wird die Bedeutung der Instruktion bei der Gestaltung von computerunterstützten Lernumgebungen erläutert. Dies geschieht anhand von Merkmalsbestimmungen und Rahmenbedingungen von Instruktionssystemen sowie am Beispiel von Fernstudienmaterial und der Lernumgebung der Virtuellen Universität

Real-world effects of anti-dementia treatment on mortality in patients with Alzheimer´s dementia

To examine the real-world effects of the cholinesterase inhibitors (AChEI) on all-cause mortality. A nationwide, retrospective cohort study. Participants were diagnosed with incident AD in Denmark from January 1, 2000 to December 31, 2011 with follow-up until December 31, 2012. A total of 36,513 participants were included in the current study with 22,063 deaths during 132,426 person-years of follow-up. At baseline, patients not treated with AChEI (n = 28,755 [9961 males (35%)]) had a mean age ± standard deviation (SD) of 80.33 ± 7.98 years (78.97 ± 8.26 for males and 81.04 ± 7.98 for females), as compared to 79.95 ± 7.67 (78.87 ± 7.61 for males and 80.61 ± 7.63 for females) in the group exposed at baseline. Patients treated with AChEI had a beneficial hazard ratio (HR) of 0.69, 95% confidence interval (CI) (0.67–0.71) for all-cause mortality as compared to patients not treated, with donepezil (HR 0.80, 95% CI [0.77–0.82]) and galantamine (HR 0.93,95% CI [0.89–0.97]) having beneficial effects on mortality rate as compared to non-treatment, whereas rivastigmine (HR 0.99, 95% CI [0.95–1.03]) was associated with a mortality rate comparable to non-treatment with AChEI. Patients were primarily exposed to donepezil (65.8%) with rivastigmine (19.8%) and galantamine (14.4%) being used less often. These findings underscore the effect of AChEI on not only reducing speed of cognitive decline but also directly prolonging life, which could result in changes in treatment recommendation for when to stop treatment

Dynamics of inelastically colliding rough spheres: Relaxation of translational and rotational energy

We study the exchange of kinetic energy between translational and rotational degrees of freedom for inelastic collisions of rough spheres. Even if equipartition holds in the initial state it is immediately destroyed by collisions. The simplest generalisation of the homogeneous cooling state allows for two temperatures, characterizing translational and rotational degrees of freedom separately. For times larger than a crossover frequency, which is determined by the Enskog frequency and the initial temperature, both energies decay algebraically like $t^{-2}$ with a fixed ratio of amplitudes, different from one.Comment: 5 pages, RevTeX, 2 eps figures, slightly expanded discussion, new figures with dimensionless units, added references, accepted for publication in PRE as a Rapid Com

Mutation of Tyrosine Sites in the Human Alpha-Synuclein Gene Induces Neurotoxicity in Transgenic Mice with Soluble Alpha-Synuclein Oligomer Formation

Overexpression of α-synuclein with tyrosine mutated to phenylalanine at position 125 leads to a severe phenotype with motor impairment and neuropathology in Drosophila. Here, we hypothesized that tyrosine mutations would similarly lead to impaired motor performance with neuropathology in a rodent model. In transgenic mice (ASO), tyrosines at positions 125, 133, and 136 in human α-synuclein were mutated to phenylalanine and cloned into a Thy1.2 expression vector, which was used to create transgenic mouse lines on a mixed genetic background TgN(Thy-1-SNCA-YF)4Emfu (YF). The YF mice had a decreased lifespan and displayed a dramatic motor phenotype with paralysis of both hind- and forelegs. Post-translational modification of α-synuclein due to phosphorylation of serine 129 is often seen in inclusions in the brains of patients with α-synucleinopathies. We observed a slight but significant increase in phosphorylation of serine 129 in the cytosol in YF mice compared to age-matched human α-synuclein transgenic mice (ASO). Conversely, significantly decreased phosphorylation of serine 129 was seen in synaptosomes of YF mice that also contained higher amounts of soluble oligomers. YF mice deposited full-length α-synuclein aggregates in neurons widespread in the CNS with the main occurrence in the forebrain structures of the cerebral cortex, the basal ganglia, and limbic structures. Full-length α-synuclein labeling was also prominent in many nuclear regions of the brain stem, deep cerebellar nuclei, and cerebellar cortex. The study shows that the substitution of tyrosines to phenylalanine in α-synuclein at positions 125, 133, and 136 leads to severe toxicity in vivo. An insignificant change upon tyrosine substitution suggests that the phosphorylation of serine 129 is not the cause of the toxicity