Le zooplancton comme bioindicateur de l’état trophique et de l’intégrité écologique des lacs du Parc du Mont-Tremblant

La gestion et le suivi des écosystèmes dans les parcs nationaux et provinciaux visent essentiellement la préservation de leur intégrité écologique et de leur biodiversité. Toutefois, le portrait de la biodiversité aquatique dans les lacs des parcs nationaux du Québec est encore incomplet, en particulier pour les microorganismes qui forment la base des réseaux trophiques. Ce mémoire présente les résultats de la première étude d’envergure sur le zooplancton de 14 lacs du parc national du Mont-Tremblant (PNMT, Québec), intégrant des connaissances nouvelles sur la biodiversité et la structure taxonomique et fonctionnelle du zooplancton et l’application d’indices biotiques. Le but final est d’établir les relations entre la structure du zooplancton et l’état trophique des lacs afin de mieux évaluer leur niveau d’intégrité biologique. La diversité et la structure du zooplancton et les patrons de dominance des espèces dans les lacs du PNMT sont similaires à ceux observés dans les lacs du Bouclier Canadien en Ontario et au Québec. On distingue plusieurs groupes de lacs sur la base des espèces de rotifères (Kellicottia longispina et Conochilus unicornis) et de cladocères de petite (Bosmina, Diaphanosoma birgei) ou grande (Daphnia catawba, Holopedium gibberum) taille. Les lacs se répartissent le long d’un gradient inverse dans l’abondance des rotifères et des copépodes calanoïdes. Ces taxons présentent le meilleur potentiel de bioindicateurs de l’état trophique des lacs du PNMT. L’altitude, la taille et la profondeur des lacs et la présence de l’Omble de fontaine ou du Grand brochet ont un effet structurant sur le zooplancton. Ils permettent de classer les lacs du PNMT en deux groupes bien distincts : i) les lacs oligotrophes à Omble de fontaine riches en copépodes calanoïdes (Allen, Herman, du Brochet, Obéron et Trap), ii) les lacs oligo-mésotrophes à Grand brochet (avec des cyprins planctivores) plus riches en rotifères (surtout Desjardins, Savane, Houdet, Monroe et Rossi).The application of environmental management plans and monitoring programs in national parks aims essentially to preserve biodiversity and ecological integrity of natural ecosystems for future generations. However, knowledge on aquatic biodiversity in national parks in Quebec is still incomplete, especially for the microorganisms at the base of food webs. This research presents the first important study on the zooplankton communities in 14 lakes of the Parc National du Mont-Tremblant (PNMT, Québec), including new knowledge on the biodiversity components, the taxonomic and functional structure of zooplankton communities, and the application of biotic indexes. The ultimate goal is to establish the relationships between trophic state and both zooplankton community structure and the derived biotic indexes, in order to evaluate the ecological integrity of the study lakes. Biodiversity components and zooplankton community structure of the PNMT lakes are similar to those observed in Canadian Shield lakes in Ontario and Québec. We could distinguish two groups of lake based on rotifer species (Kellicottia longispina and Conochilus unicornis) and on cladoceran species of small (Bosmina, Diaphanosoma birgei) or large (Daphnia catawba, Holopedium gibberum) size. Lakes are distributed along inverse gradients of the relative abundance of rotifers and calanoid copepods. These taxa offer the best potential as bioindicators of the trophic state and ecological integrity of PNMT lakes. Three main factors (altitude, area and depth of lakes, and the presence of brook trout or northern pike) are structuring zooplankton community in two main groups: i) the oligotrophic lakes with the brook trout dominated by the calanoid copepods (Allen, Herman, du Brochet, Obéron and Trap), ii) the mesotrophic lakes with the northern pike (including planktivore cyprinids) dominated by rotifers (mainly Desjardins, Savane, Houdet, Monroe and Rossi)

Effect of row spacings, seeding rates and nitrogen fertilizer rates on the agronomic performance of Yamhill and Hysolop wheat (Triticum aestivum L.)

The response of two newly released cultivars of winter wheat when grown under different row spacings, seeding rates and nitrogen levels were investigated. Measurements made included grain yield, tiller number per unit area, plant height, 300 kernel weight, bushel weight and protein content of the grain. Hyslop and Yamhill cultivars were selected since they represent different plant types and may respond differently to various cultural practices. Results indicated that optimum grain yield under the growing conditions of this study was obtained with 15. 24 cm row spacing and 134. 5 kg/ha seeding rate. Also at the 15. 24 cm row spacing, 112 kg/ha of nitrogen gave the greatest yield response. This was true for both cultivars tested. More culms per square meter were produced by the 15.24 cm row spacing. The largest number of culms being attained with 15. 24 cm spacing and 134.5 kg/ha seeding rates with both cultivars responding in a similar pattern. The plant height for both Hyslop and Yamhill remained the same at all row spacings; however the higher seeding rates resulted in increased plant height. Yamhill had a higher 300 kernel weight and a lower bushel weight than Hyslop regardless of the treatments. Different row spacings did not influence either 300 kernel weight or the bushel weight. Increased seeding rates did result in a variable 300 kernel weight and in a higher bushel weight for both cultivars. Protein content of the grain was not affected by either row spacing or seeding rates, but was influenced by nitrogen application. With the exception of the first 56 kg/ha nitrogen application, the other additional applications of nitrogen resulted in an increased protein content. Despite different growing patterns, both Hyslop and Yamhill responded similarly to the cultural practices imposed. It would appear that maximum grain yield, under the growing conditions observed in this study can be obtained by increasing the number of spikes per unit area. This could be achieved by using 15. 24 cm row spacing and 134.5 kg/ha as a seeding rate with 112 kg/ha of nitrogen. A mean of disseminating such information to the growers was also considered in this study

EVALUACIÓN DE COMPUESTOS FENÓLICOS EN POLLOS DE CARNE SOBRE EL REDEMIENTO PRODUCTIVO Y SU STATUS OXIDATIVO

La oxidación de los lípidos se puede producir por la presencia de una elevada cantidad de radicales libres, debido a un elevado consumo de ácidos grasos poliinsaturados o como resultado de una falta de antioxidantes. En general, se acepta que la oxidación de los lípidos es la principal causa del deterioro de los tejidos y que afecta directamente al valor comercial de la carne de pollo. Este proceso podría prevenirse mediante la suplementación de antioxidantes en las dietas, que minimicen la formación de los radicales libres y aumenten la estabilidad de los lípidos. En la actualidad, diversos compuestos fenólicos están siendo estudiados, debido a su potencial antioxidante. Los compuestos fenólicos son metabolitos secundarios de las plantas, que se caracterizan por minimizar las consecuencias negativas de la oxidación lipídica, pudiendo ser de interés para su uso en alimentación animal. El objetivo global de este estudio es evaluar el efecto de compuestos fenólicos, como fuente natural de antioxidantes, en pollos de carne. Noventa y seis hembras Ross 308 se asignaron al azar a 24 jaulas (4 animales por jaula) y las jaulas se distribuyeron al azar en 4 tratamientos (6 jaulas por tratamiento). Los tratamientos fueron: C-, dieta basal con 3% de aceite de pescado; C+, C- con 250 ppm de vitamina E; Dieta A, C- con 1500 ppm de producto A; Dieta B, C- con 1500 ppm de producto B. El producto A y B son productos con alto contenido de compuestos fenólicos. La suplementación dietética de los productos evaluados en este estudio, no modificó los parámetros productivos, el perfil lipídico ni el grado de oxidación de la sangre (P> 0.05). Hacen falta más estudios para valorar la efectividad de estos productos a diferentes dosis de incorporación así como la concentración y combinación de sus principios activos.<br /

Radiation zoning for vacuum equipment of the CERN Large Hadron Collider

Beam losses in high-energy particle accelerators are responsible for beam lifetime degradation. In the LHC beam losses will create a shower of particles while interacting with materials from the beam pipes and surroundings, resulting in a partial activation of material in the tunnel. Efforts have been made during the accelerator design to monitor and to reduce the activation induced by beam losses. Traceability for all vacuum components has been established providing a tool to follow-up individually each component or subcomponents installed in the tunnel, regardless of their future destination e.g. recycling or disposal. In the latter case, the history of vacuum components will allow calculating the beam-induced activation and permit comparisons with in-situ and ex-situ measurements. This zoning will also help to reduce collective and individual radiation doses to personnel during interventions. The paper presents the vacuum system layout and describes the LHC vacuum zoning and its implementation using an ORACLE© database

A Virtual CAD Model of the LHC

Integrating the large and complex LHC machine into the existing LEP tunnel is a major challenge. Space was not really a problem to fit the LEP machine into its tunnel, but LHC cryostats are much larger than the LEP quadrupoles and the external cryogenic line fills even more the tunnel. Space problems lead to small clearances. Possible conflicts, or at least the most penalising ones, between installed equipment or with transport, must be solved beforehand in order to avoid unacceptable delays and extra costs during the installation. Experience gained with LEP has already shown the help that Computer-Aided Engineering tools could provide for the integration. A virtual model of the LHC is presently prepared. The actual LEP tunnel, known with a quite good accuracy (centimetre level), has been modelled and all the elements of the machine constructed as 3D objects with the CAD system are positioned accurately on the basis of data generated from the theoretical definition. These layouts are used to generate the reference sections and to check the clearances. Examples of this powerful approach applied to engineering for accelerators are given

Vein of Galen Aneurysmal Malformation revealed by a severe heart failure and pulmonary hypertension in an infant

Neonatal and pediatric heart failure is commonly caused by congenital heart diseases, especially by large left-to-right shunting. It is rarely related to a Vein of Galen Aneurysmal Malformation (VGAM). Diagnosis and management of these cerebrovascular malformations in infancy are still difficult and remain a medical challenge. We report the case of a 2-month-old infant hospitalized for heart failure. In addition to symptoms relating to heart failure, the child presented in an agitated state with opisthotonic posture. Echocardiography showed dilated right heart cavities with pulmonary hypertension and no heart defect. Brain magnetic resonance imaging scanning confirmed the diagnosis of VGAM, showing multiple cerebral parenchyma damages. The baby was treated with diuretics and an angiotensin-converting-enzyme inhibitor leading to stabilization of her heart failure. Given the gravity of the neurological sequelae, no embolization procedure was planned for this child. She died 5 years later of acute heart failure

Effect of cinnamon supplementation on resistin and ghrelin in obese diabetic men

The object of this study was to determine the effect of Cinnamomum zeylanicum (cinnamon) on glycemic/lipid balance, resistin and ghrelin. 84 obese Type 2 diabetic patients were assigned in 2 groups which consumed 8 g and 4 g of cinnamon powder. Anthropometric, hormonal and biochemical parameters were measured before and after 10 weeks of treatment. We found that cinnamon decrease BMI and waist circumference respectively of -5.52±1.47 kg/m² and -10.72±6.12 cm for group 2 of and a decrease of -4.45±1.46 kg/m² and -6.86±5.5 cm in group 1. Our results also showed a decrease of the glucose level of -1,173±0, 75 mmol/L in group 2 and -0, 8932±0, 72 mmol/L in group 1 and a decrease of insulin levels of -3.24±2.85 μUI/L in group 2 and -2.54±2.8 μUI/L in group 1. The assays showed that resistin secretion decreased by -2.08±1.09 ng/mL for the 8 g dose and -1.59±0.926 ng/mL for the 4 g dose, and there was an increase in ghrelin secretion of +1.55±2.21 μg/mL for the 8 g dose and + 2.49±1.13 μg/mL for the 4 g dose. The results confirmed the anti-hyperglycemic and hypolipidemic effects of cinnamon opening a new approach to studying how the compounds derived from certain spices regulate the endogenous release of hormones such as ghrelin and resistin for therapeutic intervention

X-linked susceptibility to mycobacteria is caused by mutations in NEMO impairing CD40-dependent IL-12 production

Germline mutations in five autosomal genes involved in interleukin (IL)-12–dependent, interferon (IFN)-γ–mediated immunity cause Mendelian susceptibility to mycobacterial diseases (MSMD). The molecular basis of X-linked recessive (XR)–MSMD remains unknown. We report here mutations in the leucine zipper (LZ) domain of the NF-κB essential modulator (NEMO) gene in three unrelated kindreds with XR-MSMD. The mutant proteins were produced in normal amounts in blood and fibroblastic cells. However, the patients' monocytes presented an intrinsic defect in T cell–dependent IL-12 production, resulting in defective IFN-γ secretion by T cells. IL-12 production was also impaired as the result of a specific defect in NEMO- and NF-κB/c-Rel–mediated CD40 signaling after the stimulation of monocytes and dendritic cells by CD40L-expressing T cells and fibroblasts, respectively. However, the CD40-dependent up-regulation of costimulatory molecules of dendritic cells and the proliferation and immunoglobulin class switch of B cells were normal. Moreover, the patients' blood and fibroblastic cells responded to other NF-κB activators, such as tumor necrosis factor-α, IL-1β, and lipopolysaccharide. These two mutations in the NEMO LZ domain provide the first genetic etiology of XR-MSMD. They also demonstrate the importance of the T cell– and CD40L-triggered, CD40-, and NEMO/NF-κB/c-Rel–mediated induction of IL-12 by monocyte-derived cells for protective immunity to mycobacteria in humans