170 research outputs found
Sous-typage coercitif en présence de réductions non-standards dans un système aux types dépendants
Type Theory lies on the crossroad of Logics, Mathematics and Computer Science. It may be used to develop the "zero-error" programs. The aim of this thesis is to study an extension of a system with dependent types called UTT (including inductive types) that is obtained by adding to the rewrite relation of UTT new rewrite rules concerning finite types. We check that Strong Normalization, Church-Rosser property and Subject Reduction are preserved. We consider another extension by Coercive Subtyping that is seen as an abbreviation mechanism and give a conservativity proof for the system enriched by Coercive Subtyping with respect to underlying UTT (with an without new rewrite rules). The interest of such a system is that it will improve the efficiency of proof assistants and provides a general framework for treatment of the problems involving finite types (combinatorics, graphs etc).La théorie des types est une discipline au croisement de la logique, des mathématiques et de l'informatique. Elle peut servir de support au développement de programme "zéro faute". L'objet de cette thèse est d'étudier l'extension d'un système aux types dépendants UTT (comprenant notamment des types inductifs) par une relation de récriture concernant un fragment du calcul, à savoir les types finis. Nous nous assurons d'abord que les propriétés de normalisation forte, de confluence et de préservation du type sont toujours préservées malgré l'ajout de la réduction. Ensuite nous enrichissons ce système par la notion de sous-typage coercitif vue comme un mécanisme d'abréviation et effectuons la preuve de conservativité pour le système enrichi du sous-typage par rapport au système de base. L'intérêt d'un tel système est qu'il améliora l'efficacité des assistants à la preuve et offrira un bon cadre pour l'étude des problèmes faisant intervenir des ensembles finis (combinatoire, manipulation de graphe etc)
Perception des mères sur l'établissement de la relation mère-bébé en contexte d'allaitement difficile ayant mené au sevrage
Problématique : L'allaitement, encouragé par l'Organisation mondiale de la santé (OMS) comme mode d'alimentation idéal pour les mères et leurs enfants, devient de plus en plus populaire (Statistique Canada, 2012). Au Canada, son initiation dépasse 90 %, cependant 19 % des mères sèvrent dès le premier mois. Un des avantages attribué à l'allaitement est qu'il favorise la relation mère-bébé (Smith et Ellwood, 2011), mais qu'en est-il si l'expérience d'allaitement est difficile? Peu d’études explorent ce thème et surtout elles restent vagues sur les impacts d’une telle expérience sur la relation mère-bébé. But : L'étude vise à décrire l'établissement de la relation mère-bébé selon la perspective de mères ayant sevré suite à une expérience d'allaitement difficile. Méthode : Un devis mixte a été utilisé. Douze mères ont répondu à des questionnaires et participé à une entrevue individuelle portant sur l’expérience d’allaitement difficile menant au sevrage et sur la relation mère-bébé en contexte d'allaitement difficile. Des analyses descriptives ont été faites pour les données quantitatives et de contenu pour les données qualitatives. Résultats : Les difficultés d’allaitement ont commencé dès l’initiation et ont perduré toute la durée de l’expérience d’allaitement. Dans ce contexte d'allaitement difficile, les participantes ont rapporté être moins prédisposées à connaitre leur bébé, à communiquer avec lui et elles ont vécu des échanges affectifs positifs et négatifs avec lui. Suite au sevrage, elles ont dit découvrir et communiquer davantage avec leur bébé. Avec les difficultés d’allaitement et le choix de sevrer, elles sont appelées à redéfinir leur rôle de mère auprès de leur bébé et elles ont ressenti une culpabilité passagère. Face à aux défis d’être attentive à la relation avec leur bébé, d’évoluer dans le rôle de mère et de dépasser la culpabilité vécue, les mères ont besoin de soutien. Retombées : En contexte d'allaitement difficile, la relation mère-bébé pourrait bénéficier du soutien des infirmières qui ont une proximité avec les dyades mère-bébé pour les aider à surmonter les défis relationnels. Suite au sevrage, les mères ont besoin d'être soutenues particulièrement face à la culpabilité ressentie
Effect of selective anthelmintic treatments on health and production parameters in Pelibuey ewes during lactation
A study was conducted from December to April 2013, with the aim of evaluating a system of selective antiparasitic treatments using the FAMACHA© color chart compared with a conventional suppressive deworming system every 30 days in Pelibuey ewes during lactation. For the study, 54 ewes were used. They were randomly divided into two groups: FAMACHA and chemical treatments. The ewes in the first group received selective treatment depending on the ocular mucosa coloration (FAMACHA) and body condition score (BCS), while in the second group (chemical) all the animals remained under routine deworming every 30 days. Fecal nematode egg counts, proportion of third-stage trichostrongylid larvae, body condition, coloration of the ocular mucosa, and packed cell volume in the ewes were determined, while in lambs only body weight (BW) was recorded. No significant differences (p>0.05) were observed in any of the studied variables between groups; however, the use of antiparasitic drugs was reduced during the experimental period in the FAMACHA group and no deaths of lambs or ewes were recorded. The results indicate that during the lactation of ewes, a strategy of selective treatments can be implemented without showing deterioration in major health and productive parameters of these animals.cub
Nutraceutic effect of free condensed tannins of lysiloma acapulcensis (kunth) benth on parasite infection and performance of pelibuey sheep
Abstract Forty-five Pelibuey sheep were experimentally infested with nematodes to evaluate the effect of three free condensed tannin (FCT) levels of Lysiloma acapulcensis on fecal egg counts (FECs), packed cell volumes (PCV), ocular mucosa colors (OMC), average daily gain (ADG), and adult nematode count. Five treatments were used: 12.5, 25.0, and 37.5 mg of FCT kg−1 of body weight (BW); sterile water (control); and ivermectine (0.22 mg kg−1 of BW) as chemical group. The data were processed through repeated measure- ment analysis. Even though the three FCT doses decreased (P < 0.05) the FEC, the highest reduction was obtained with 37.5 mg kg−1 of BW. No differences were observed in PCV and OMC. Higher ADG (P < 0.05) was observed with 37.5 mg kg−1 of BW of FCT. The count of adult nematodes (females and males) in the higher dose of FCT was similar to chemical treatment. Dose of 37.5 mg kg−1 of BW decreased the parasite infection and improved the lamb performance. Therefore, this dose could be used as a nutraceutic product in sheep production.This work was undertaken with funds from the Universidad Autónoma del Estado de México (Project UAEM 1026/2014RIFC). Our gratitude also goes to the Mexican National Council for Science and Technology (CONACYT) for the grant received by Cesar GarcÃa Hernández
Atypical BSE (BASE) Transmitted from Asymptomatic Aging Cattle to a Primate
BACKGROUND: Human variant Creutzfeldt-Jakob Disease (vCJD) results from foodborne transmission of prions from slaughtered cattle with classical Bovine Spongiform Encephalopathy (cBSE). Atypical forms of BSE, which remain mostly asymptomatic in aging cattle, were recently identified at slaughterhouses throughout Europe and North America, raising a question about human susceptibility to these new prion strains. METHODOLOGY/PRINCIPAL FINDINGS: Brain homogenates from cattle with classical BSE and atypical (BASE) infections were inoculated intracerebrally into cynomolgus monkeys (Macacca fascicularis), a non-human primate model previously demonstrated to be susceptible to the original strain of cBSE. The resulting diseases were compared in terms of clinical signs, histology and biochemistry of the abnormal prion protein (PrPres). The single monkey infected with BASE had a shorter survival, and a different clinical evolution, histopathology, and prion protein (PrPres) pattern than was observed for either classical BSE or vCJD-inoculated animals. Also, the biochemical signature of PrPres in the BASE-inoculated animal was found to have a higher proteinase K sensitivity of the octa-repeat region. We found the same biochemical signature in three of four human patients with sporadic CJD and an MM type 2 PrP genotype who lived in the same country as the infected bovine. CONCLUSION/SIGNIFICANCE: Our results point to a possibly higher degree of pathogenicity of BASE than classical BSE in primates and also raise a question about a possible link to one uncommon subset of cases of apparently sporadic CJD. Thus, despite the waning epidemic of classical BSE, the occurrence of atypical strains should temper the urge to relax measures currently in place to protect public health from accidental contamination by BSE-contaminated products
Luminescence Properties of Mesoporous Silica Nanoparticles Encapsulating Different Europium Complexes: Application for Biolabelling
In this work we have synthesized and characterized new hybrid nanoplatforms for luminescent biolabeling based on the concept of Eu3+ complexes encapsulation in mesoporous silica nanoparticles (≈100 nm). Eu complexes have been selected on the basis of their capability to be excited at 365 nm which is a currently available wavelength, on routine epifluorescence microscope. For Eu complexes encapsulation, two different routes have been used: the first route consists in grafting the transition metal complex into the silica wall surface. The second way deals with impregnation of the mesoporous silica NPs with the Eu complex. Using the second route, a silica shell coating is realized, to prevent any dye release, and the best result has been obtained using Eu-BHHCT complex. However, the best solution appears to be the grafting of Eu(TTA)3-Phen-Si to mesoporous silica NPs. For this hybrid, mSiO2-Eu(TTA)3(Phen-Si) full characterization of the nanoplatforms is also presented
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