The role of E1-E2 interplay in multiphonon Coulomb excitation

In this work we study the problem of a charged particle, bound in a harmonic-oscillator potential, being excited by the Coulomb field from a fast charged projectile. Based on a classical solution to the problem and using the squeezed-state formalism we are able to treat exactly both dipole and quadrupole Coulomb field components. Addressing various transition amplitudes and processes of multiphonon excitation we study different aspects resulting from the interplay between E1 and E2 fields, ranging from classical dynamic polarization effects to questions of quantum interference. We compare exact calculations with approximate methods. Results of this work and the formalism we present can be useful in studies of nuclear reaction physics and in atomic stopping theory.Comment: 10 pages, 6 figure

Identification of a Novel Signaling Pathway and Its Relevance for GluA1 Recycling

We previously showed that the serum- and glucocorticoid-inducible kinase 3 (SGK3) increases the AMPA-type glutamate receptor GluA1 protein in the plasma membrane. The activation of AMPA receptors by NMDA-type glutamate receptors eventually leads to postsynaptic neuronal plasticity. Here, we show that SGK3 mRNA is upregulated in the hippocampus of new-born wild type Wistar rats after NMDA receptor activation. We further demonstrate in the Xenopus oocyte expression system that delivery of GluA1 protein to the plasma membrane depends on the small GTPase RAB11. This RAB-dependent GluA1 trafficking requires phosphorylation and activation of phosphoinositol-3-phosphate-5-kinase (PIKfyve) and the generation of PI(3,5)P2. In line with this mechanism we could show PIKfyve mRNA expression in the hippocampus of wild type C57/BL6 mice and phosphorylation of PIKfyve by SGK3. Incubation of hippocampal slices with the PIKfyve inhibitor YM201636 revealed reduced CA1 basal synaptic activity. Furthermore, treatment of primary hippocampal neurons with YM201636 altered the GluA1 expression pattern towards reduced synaptic expression of GluA1. Our findings demonstrate for the first time an involvement of PIKfyve and PI(3,5)P2 in NMDA receptor-triggered synaptic GluA1 trafficking. This new regulatory pathway of GluA1 may contribute to synaptic plasticity and memory

Up-regulation of IGF-1 in the frontal cortex of piglets exposed to an environmentally enriched arena

Environmental enrichment (EE) is widely used in the life sciences to study effects of environment on the brain. In pigs, despite lack of EE being a key welfare issue there is little understanding of brain effects of EE in pigs. This project aimed to study the effects of exposure to an EE arena on piglet behaviours and on brain gene expression levels with a focus on IGF-1 and related genes. Eight litters of large white × landrace × Hampshire piglets were farrowed and raised in a free farrowing system (PigSAFE). At 42 days of age, 6 piglets per litter were given access to an enriched arena with plentiful peat, straw and space, (in groups of 4 made up of stable pairs) for 15 min per day on 5 consecutive days to allow them to habituate to the apparatus. Piglet behaviours were recorded in the arena for 15 min periods on 3 consecutive days. On the final day only one pair of test piglets per litter was given access to the arena. Brain tissue was collected within 45 min of the test from piglets exposed to the arena on the day and their non-exposed littermate controls. RNA was extracted from the frontal cortex and QRT-PCR for selected genes run on a Stratgene MX3005P. In both the home pen and the EE arena litters spent the largest proportion of time engaging in foraging behaviour which was significantly increased in the enriched arena (t(7) = 5.35, df = 6, p = 0.001). There were decreases in non-running play (t(7) = 4.82, p = 0.002) and inactivity (t(7) = 4.6, p = 0.002) in the arena. A significant fold change increase (FC = 1.07, t = 4.42, p = 0.002) was observed in IGF-1 gene expression in the frontal cortex of piglets exposed to the enriched arena compared to those not exposed on the day of culling. No change in expression was observed in CSF1, the IGF-1 receptor gene nor in any of the binding proteins tested (IGFBP1-6). There was a weak tendency for increased expression of the neurotrophic factor BDNF1 (fold change: 1.03; t(7) = 1.54, p = 0.1). We believe this work is the first to explore effects of EE on pig brain physiology and development, and also points to a potential role for IGF-1 in brain effects of EE

Measuring Performance for Accountability of a Small Social Economy Organization: The Case of an Independent School

This article is a result of a joint project in social economy research between a community partner-an independent school-and academic partners. The school is a democratic organization, run by teachers and parents. The goal of the project was to find ways to improve communication and reporting about general performance of the school as part of the school's accountability to its members. Starting from lessons of the balanced scorecard approach for non-profits, we describe the process of development of survey-based measures for the particular organization. The direction of the tool development and subsequent organizational changes were carried out in a participatory process between the school's staff, the parents, and the board. We identify the limitations and challenges of this process, and outline its successes to draw lessons for other similar democratic organizations. / Cet article est le produit d'un projet conjoint de recherche sur l'économie sociale entre un partenaire communautaire-une école privée-et des partenaires académiques. L'école est une organisation démocratique dirigée par des enseignants et des parents. Le but de ce projet était de trouver des façons d'améliorer la communication et la reddition de compte en ce qui a trait au rendement général de l'école comme faisant partie de la responsabilité de l'école envers ses membres. En commençant par des leçons sur l'approche de tableau de bord équilibré pour les organismes sans but lucratif, nous abordons le processus de l'élaboration de mesures fondées sur des enquêtes pour l'organisation particulière. L'orientation du développement d'outils et des changements organisationnels subséquents ont été déterminés lors d'un processus participatif entre le personnel de l'école, les parents et la direction. Nous établissons les limites et les défis de cette façon de procéder et en soulignons les réussites pour tirer des leçons qui serviront à d'autres organisations démocratiques comparables