Évolution de la structure des communautés bactériennes au cours d'un élevage larvaire de plie rouge (Pseudipleuronectes americanus)

A l'heure actuelle, le domaine de l'aquaculture est en pleine expansion et la production de juvéniles de poissons marins de qualité devient un enjeu majeur pour les producteurs aquicoles. Cette production intensive comporte certains risques dont l'apparition de maladies bactériennes provoquée principalement par le pathogène Vi brio induisant la hausse du taux de mortalité des stades larvaires. Cette étude a pour but de démontrer l'existence de relations entre la structure des communautés bactériennes et le régime alimentaire fourni à des larves de plie rouge (Pseudopleuronectes americanus), plus particulièrement lors de l'emploi d'un régime alimentaire riche en acides gras (AG) essentiels reconnus pour leur effet benéfique sur la croissance larvaire. Les analyses microbiologiques comprenaient des mesures d'abondance totale (analyses d'abondance bactérienne totale par cytométrie en flux) et spécifique (dénombrement des bactéries cultivables et de Vibrio sp.) ainsi que des analyses de diversité. Nos résultats ont démontré une augmentation de l'abondance bactérienne totale pour les régimes alimentaires soumis à un ajout d'AG. Les cytogrammes obtenus par cytométrie en flux ont révélé une dynamique de l'évolution des communautés bactériennes dans les bassins différente de celle enregistrée dans le contrôle d'eau de mer. L'abondance des bactéries cultivables a diminué au cours du temps dans tous les bassins d'élevage quel que soit le régime alimentaire testé. L'abondance du pathogène Vibrio sp. a subi une augmentation dans tous les bassins d'élevage. De plus, les analyses génétiques ont révélé une diminution du coefficient de Jaccard permettant ainsi d'émettre l'hypothèse que la diversité de communauté a changé au cours du temps d'échantillonnage dans tous les bassins d'élevage quel que soit le traitement employé. Malgré le fait qu'on ait constaté des différences entre les régimes alimentaires, nos résultats n'ont pas démontré si un traitement était avantageux pour améliorer la qualité de l'eau d'élevage et la croissance larvaire

The international landscape of positive psychology research: A systematic review

Since positive psychology originated in 1998 as an organized stream of inquiry in theUnited States, it has inspired new theory and research on human flourishing across the world. The current systematic review presents an overview of (a) the prevalence of scientific research in positive psychology across five continents and 63 countries, (b) the characteristics of the research, including methodology and topics, and (c) the influence of positive psychology in expanding established lines of research in new ways. Through an analysis of 863 peer-reviewed positive psychology articles, this review attempts to map the international landscape of positive psychology research. Further, it responds to relevant critiques of the field, confirming some and dispelling others. Finally, recommendations are shared for future directions to build a more culturally responsive field of positive psychology that is committed to the advancement of flourishing and wellbeing in the global context

In-plane and Out-of-plane Plasma Resonances in Optimally Doped La1.84Sr0.16CuO4

We addressed the inconsistency between the electron mass anisotropy ratios determined by the far-infrared experiments and DC conductivity measurements. By eliminating possible sources of error and increasing the sensitivity and resolution in the far-infrared reflectivity measurement on the single crystalline and on the polycrystalline La1.84Sr0.16CuO4, we have unambiguously identified that the source of the mass anisotropy problem is in the estimation of the free electron density involved in the charge transport and superconductivity. In this study we found that only 2.8 % of the total doping-induced charge density is itinerant at optimal doping. Our result not only resolves the mass anisotropy puzzle but also points to a novel electronic structure formed by the rest of the electrons that sets the stage for the high temperature superconductivity

The Mental Health Agency Research Network (MHARN): Developing a statewide network for knowledge sharing, technical assistance & collaborative research

The Mental Health Agency Research Network (MHARN) is a developing network for sharing knowledge and research collaboration between the UMMS Dept. of Psychiatry and other academics, DMH personnel, community providers, consumers and family members. Its mission is to close the gap between science and service in mental health services in Massachusetts by improving implementation of evidence based practices to benefit consumers. The MHARN provides a structure and mechanism for the Center for Mental Health Services Research (CMHSR) to better engage with DMH staff and community agencies around the state. As experience and research on science-to-service has demonstrated that dissemination of information about research findings is not sufficient to bring about changes in practice and benefits to consumers, the MHARN will incorporate principles and practices of the emerging science of implementation research

Isotropic three-dimensional gap in the iron-arsenide superconductor LiFeAs from directional heat transport measurements

The thermal conductivity k of the iron-arsenide superconductor LiFeAs (Tc ~ 18K) was measured in single crystals at temperatures down to T~50mK and in magnetic fields up to H=17T, very close to the upper critical field Hc2~18T. For both directions of the heat current, parallel and perpendicular to the tetragonal c-axis, a negligible residual linear term k/T is found as T ->0, revealing that there are no zero-energy quasiparticles in the superconducting state. The increase in k with magnetic field is the same for both current directions and it follows closely the dependence expected for an isotropic superconducting gap. There is no evidence of multi-band character, whereby the gap would be different on different Fermi-surface sheets. These findings show that the superconducting gap in LiFeAs is isotropic in 3D, without nodes or deep minima anywhere on the Fermi surface. Comparison with other iron-pnictide superconductors suggests that a nodeless isotropic gap is a common feature at optimal doping (maximal Tc).Comment: 4 pages, 3 figure

New Phase Induced by Pressure in the Iron-Arsenide Superconductor K-Ba122

The electrical resistivity rho of the iron-arsenide superconductor Ba1-xKxFe2As2 was measured in applied pressures up to 2.6 GPa for four underdoped samples, with x = 0.16, 0.18, 0.19 and 0.21. The antiferromagnetic ordering temperature T_N, detected as a sharp anomaly in rho(T), decreases linearly with pressure. At pressures above around 1.0 GPa, a second sharp anomaly is detected at a lower temperature T_0, which rises with pressure. We attribute this second anomaly to the onset of a phase that causes a reconstruction of the Fermi surface. This new phase expands with increasing x and it competes with superconductivity. We discuss the possibility that a second spin-density wave orders at T_0, with a Q vector distinct from that of the spin-density wave that sets in at T_N.Comment: Two higher K concentrations were added, revealing a steady expansion of the new phase in the T-P phase diagra