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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
351

Etude génotypique de norovirus humains et bovins contemporains et mise au point de méthodes rapides de détection et de quantification

Scipioni, Alexandra 25 May 2009 (has links)
Les Norovirus (NoV), appartenant à la famille des Caliciviridae, sont une cause majeure dépidémies et de cas sporadiques de gastroentérites hautement contagieuses chez lhomme. Leur transmission emprunte la voie fécale-orale et ils sont à l'origine dune part importante des toxi-infections humaines d'origine alimentaire, en particulier dues à la consommation de mollusques bivalves. Ils possèdent un génome constitué dARN monocaténaire de polarité positive et sont classeés par analyse de proximité génétique en cinq génogroupes, contenant chacun plusieurs génotypes. Un problème majeur réside dans lincapacité à multiplier facilement les NoV en culture de cellules. La RT-PCR est devenue la méthode de choix pour leur détection dans les échantillons de matières fécales, les denrées alimentaires et les prélèvements effectués dans lenvironnement. Il est important de disposer de techniques à la fois sensibles et permettant également la détection dun large panel de NoV. La quantification de la charge virale est possible par lutilisation des techniques de RT-PCR en temps réel et est primordiale pour non seulement déterminer le niveau de contamination dun prélèvement, mais également pour étudier et caractériser la pathogénie de linfection à NoV. Des NoV ont été détectés dans diverses espèces animales, dont lespèce bovine. Ces découvertes ont soulevé d'importantes questions sur une éventuelle transmission zoonotique et l'existence d'un réservoir animal pour les NoV. La caractérisation moléculaire des deux prototypes de NoV bovins, nommément le virus Newbury2 et le virus Jena, a révélé qu'ils étaient génétiquement proches et associés aux NoV humains. Parmi les hypothèses évoquées, les animaux pourraient être soit des porteurs passifs de NoV, soit infectés de manière active par ces virus, responsables dès lors d'une zoonose. Caractériser les NoV circulant chez lhomme et les espèces animales est intéressant dans le but détudier leurs voies de transmission et léventuel passage inter-espèce de ces virus. Un mécanisme important d'évolution des NoV est la recombinaison, dun grand intérêt dans létude des NoV, générant des modifications du génome viral aboutissant à la création dun génome « chimère » à partir de deux génomes parentaux différents. Elle crée ainsi de la variation génétique et par là lémergence de nouveaux virus. En effet, il est bien documenté que la recombinaison se produit souvent parmi les NoV et contribue à la diversité génétique de ces virus ainsi quà lapparition de nouvelles épidémies. La prévalence des souches de NoV recombinants peut être sous-estimée par le fait que la caractérisation des NoV est habituellement basée sur le séquençage partiel du gène de lARN polymérase-ARN dépendante uniquement, alors quidéalement il faudrait séquencer différentes parties du génome, principalement lARN polymérase-ARN dépendante et la protéine de capside, pour identifier de tels virus. Il est important de déterminer précisément l'implication exacte de la recombinaison sur lévolution des NoV afin de comprendre les mécanismes dévolution des souches et l'avantage sélectif conféré pour certaines dentre elles. Etudier ce mécanisme permettra de mieux comprendre lavantage sélectif observé pour certains NoV et aidera à élucider les voies de transmission des NoV. Létude de ces deux points (transmission zoonotique et virus recombinants) est primordiale. En effet, le franchissement de la barrière despèce affecterait à la fois l'épidémiologie et l'évolution de ces virus, et compliqueraient également la capacité au développement dun vaccin ou dun traitement. Dans d'autres espèces animales, comme les chevaux ou les oiseaux, aucun NoV na été détecté à ce jour mais ces dernières années, des NoV ont été décrits dans de nombreuses espèces animales (chien, lion, mouton). Cela laisse donc présager dune gamme despèce cible encore plus étendue. Ce travail sinscrit dans le cadre de létude des voies de transmission des NoV avec comme objectif, après la mise au point de méthodes rapides et sensibles de détection et de quantification, dapporter un éclaircissement aux questions importantes relatives à lévolution des NoV et à leur catégorie dhôte. Dans un premier temps, la RT-PCR conventionnelle a été utilisée afin de détecter les NoV dans les espèces humaine et bovine. Ensuite, une RT-PCR utilisant la technologie SYBR Green a été développée et utilise un contrôle interne constitué dARN ajouté au même tube. Ce test est capable de détecter des NoV humains et bovins appartenant aux génogroupes I, II et III et permet de faire la distinction entre les NoV et le contrôle interne par lanalyse des courbes de dissociation. Une dilution 10 fois des échantillons sest révélée la méthode de choix pour lever les inhibitions. Afin de pouvoir confirmer directement le résultat et de permettre la quantification des NoV, une RT-PCR en temps réel utilisant la technologie TaqMan a été développée. Elle utilise un contrôle interne dARN et un standard dARN. De façon très intéressante, cette méthode peut détecter les NoV humains appartenant au génogroupes I, II et bovins du génogroupe III. Les inhibitions furent efficacement levées par une dilution 10 fois de léchantillon ou lajout de sérum albumine bovine au mix de RT-PCR. Ces deux RT-PCR en temps réel ont montré une sensibilité supérieure comparée à la RT-PCR conventionnelle. Avec pour objectif de comprendre les voies de transmission des NoV, la situation en Belgique a été investiguée et des NoV humains et bovins ont été détectés et analysés par séquençage partiel. Des NoV appartenant à différents génogroupes ont été détectés : GI et GII chez lhomme et GIII chez les bovins. Par analyse de la proximité génétique, les NoV bovins se sont révélés de génotype GIII.2 et les NoV humains de différents génotypes, mais majoritairement de génotype GII.4. Ces analyses ont permis également lidentification dune co-infection et de deux recombinants naturels, ces derniers étant proches de génotypes différents en fonction de la région du génome analysée (polymérase ou capside). L'identification de zones privilégiées pour la recombinaison dans la région située à la jonction de l'ORF (open reading frame) 1 et de lORF2 confirme l'importance de cette région dans ce phénomène. Afin détudier lévolution des NoV bovins, un NoV bovin détecté en Belgique fut séquencé complètement (Bo/B309/2003/BE) et comparé à la souche originale Newbury2 (isolée dans les années 80). Dune part, cette études a permis daboutir à la mise au point et la validation doutils permettant la détection et létude les NoV humains et animaux, tant pour leur pathogénie, que leur évolution ou leurs voies de transmission. Dautre part, basée sur le panel déchantillons recueillis durant cette étude, lanalyse phylogénétique des NoV détectés va dans le sens des études réalisées dans dautres pays tendant à montrer que les NoV bovins constituent un groupe de virus distincts, différents des NoV humains. Cela suggère que les NoV bovins ne représentent pas un risque pour la santé humaine. Néanmoins, la possibilité dune infection zoonotique ou dun réservoir animal ne peut pas être exclue vu la proximité de séquence entre les NoV humains et animaux et aussi la relation étroite et proche entre les populations humaines et les élevages danimaux. La détection dune co-infection et de deux recombinants naturels démontre les possibilités dévolution des NoV et limportance dune analyse complète de leur génome pour leur caractérisation. Ce travail a été pionnier dans létude des NoV au laboratoire et a ouvert la voie à dautres sujets de recherche sur les NoV et à de nouvelles thèses de doctorat, notamment sur létude de linteraction NoV-hôte (NoV dans lespèce bovine) et létude de la recombinaison des NoV in vitro (NoV murins).
352

Over-current relay model implementation for real time simulation & Hardware-in-the-Loop (HIL) validation

Almas, Muhammad Shoaib, Leelaruji, Rujiroj, Vanfretti, Luigi January 2012 (has links)
Digital microprocessor based relays are currently being utilized for safe, reliable and efficient operation of power systems. The overcurrent protection relay is the most extensively used component to safeguard power systems from the detrimental effects of faults. Wrong settings in overcurrent relay parameters can lead to false tripping or even bypassing fault conditions which can lead to a catastrophe. Therefore it is important to validate the settings of power protection equipment and to confirm its performance when subject to different fault conditions. This paper presents the modeling of an overcurrent relay in SimPowerSystems (\textsc {matlab}/Simulink). The overcurrent relay has the features of instantaneous, time definite and inverse  definite minimum time (IDMT) characteristics. A power system is modeled in SimPowerSystems and this overcurrent relay model is incorporated in the test case. The overall model is then simulated in real-time using Opal-RT's eMEGAsim real-time simulator to analyze the relay's performance when subjected to faults and with different characteristic settings in the relay model. Finally Hardware-in-the-Loop validation of the model is done by using the overcurrent protection feature in Schweitzer Engineering Laboratories Relay SEL-487E. The event reports generated by the SEL relays during Hardware-in-the-Loop testing are compared with the results obtained from the standalone testing and software model to validate the model. / <p>QC 20130215</p>
353

Encystment of Acanthamoeba and Evaluating the Biobus Program

Trevisan, Brandi C 18 August 2010 (has links)
Acanthamoeba are ubiquitous protists that play an environmental role in regulating microbial diversity; they also occasionally cause infections of the eye (Acanthamoeba keratitis) and brain (granulomatous amoebic encephalitis). These organisms exhibit two distinct phenotypes. The trophozoite form dominates in favorable conditions, in which the Acanthamoeba move through the extension of pseudopodia, engulfing microbes and other particles. During stressful conditions, the Acanthamoeba undergo a process of encystment, in which they build a double cell wall and become relatively inactive. The cyst form can survive years until more favorable conditions arise, at which point they may excyst. For this study, multiple laboratory encystment methods were compared to determine the percent encystment and the different viabilities of laboratory-produced cysts. Furthermore, four different encystment genes were targeted for development of a primer library for reverse-transcription, polymerase chain reaction expression studies. The library was developed using sequences accessed from various databases, including NCBI and EMBL; primers were screened through polymerase chain reaction, and those primers producing positive results were used to further screen cellular RNA that was extracted from encysting cells over various time points during the encystment process, and using various encystment media. Using these methods, target gene involvement in the encystment process was compared between species and encystment methods. These studies lay the foundation for quantitative gene expression analysis, and provide the basis for comparison of various encystment methods.
354

Expression profiling and function analyses on avian sex-determining candidate genes, DMRT1 and HINT1

Tsai, Hsin-yin 15 July 2004 (has links)
To establish the gene expression profile and cascade subsequently on avian sex-determining candidate genes, seven avian sex-determining candidate genes including DMRT1, FET1, FOXL2, LHX9, HINT1, SMC2L1 and SOX9 were analyzed at early embryogenesis. Quantitative reverse transcription PCR (Quantitative RT-PCR) technology was used to establish the gene expression profiles among these genes at four, five, six and seven days of embryos. The results of quantitative RT-PCR reveal that the DMRT1 was expressed in chicken embryos of both sexes. DMRT1 gene expressions were up-regulated at four, five and six days of chicken embryos. DMRT1 expression increased at 5-Dpc. of male embryos, however, expression was not signification different in females embryos. Gene expression of FET1, FOXL2, LHX9 and HINT1 were higher in females than in males. The SMC2L1 and SOX9 were expressed in both sexes. Also, to identify the novel sex-determination genes in early chicken subtractive embryos, cDNA libraries from male-minus-female and female-minus-male 3.5 Dpc. embryos cDNA were established. Gene annotation was carried out by data-mining in public databases, GeneBank (NCBI, USA) and TIGR gene indices (The Institute for Genome Research, USA). A total 548 of colonies in male-minus-female library and 79 sequences were annotated. However, a total of 589 of colonies in female-minus-male library and 16 sequences were annotated. Sequences were homologous to the steroid 5£\-reductase protein (SRD5A1) using BLASTx in male-minus-female subtractive library. The SRD5A1 may play a sex-differentiation role in male chicken. We need more study to know function of steroid 5£\-reductase protein in future.
355

Identification of drought responsive genes in aleppo pine (Pinus halepensis) and loblolly pine (Pinus taeda.L)

Sathyan, Pratheesh 17 February 2005 (has links)
Drought is a major constraint for attaining economic yield in tree crops. As an initial step to understand molecular response to water-deficit-stress in trees, gene expression in response to water stress was quantified using real-time RT-PCR. The specific objectives established for this to were I. to identify and characterize the genes induced by drought stress in Aleppo pine (Pinus halepensis) and II to identify and quantify the differentially expressed genes in different populations of Loblolly pine (Pinus taeda.L) due to water deficit (chapter III). Results of these studies may be used to identify candidate genes for future breeding programs against water-deficit-stress.
356

The regulation of advanced nursing practice

O'Shea, Rose Ann January 2013 (has links)
The typical picture that is conjured up when one thinks of a nurse is that of a matronly figure, in a uniform and cap, sitting at the patient’s bedside administering care. Associated with this is the traditional view held by the public, in which nurses are beholden to doctors and dependent on them for instruction, and perform a generally subservient role. However, those who have had the misfortune to require treatment more recently will testify to a far different situation, in which nurses perform a more professional and clinically autonomous role, as well as having a caring and compassionate function. In fact, the picture that exists in most clinical environments is one in which nurses are recognised as knowledgeable and capable clinicians, and independent practitioners in their own right, rather than obedient medical handmaidens. The delivery of modern healthcare has also changed beyond recognition, with interventions that were once considered to be the domain of hospital practitioners now provided in a more liberated community-based system. Within this structure, the role of healthcare professionals has similarly been transformed, such that the ‘power’ has shifted away from doctors and towards non-medical clinicians. This has, in turn, resulted in non-medical practitioners, most notably nurses, having more authority, autonomy and responsibility for clinical decision-making, rendering them more equal in the clinical hierarchy and more evenly aligned as professionals. This thesis explores the range of traditional medical activities that are now performed by nurses who have expanded their practice in order to accommodate the additional responsibilities that this 'power' affords. In particular, it looks at those nurses who have advanced their practice such it constitutes a new clinical role and, in some cases, act as medical substitutes. With the further devolution of clinical tasks inevitable, and the creation of more clinical roles likely, this thesis looks at the regulatory framework that underpins advanced nursing practice. In particular, it questions whether the existing framework provides the regulatory safeguards that are required to ensure patient and public protection and asks whether an alternative approach, such as that which is provided by another professional regulator, may be more appropriate. In concluding, this thesis will assert that a compelling case for the statutory regulation of advanced nursing practice can be made, and will suggest a number of options regarding how this regulatory solution can be achieved.
357

Continuing professional education : exploring the experience of community nurses working on a small remote island

Lemprière, Julie A. January 2013 (has links)
Qualified nurses require equitable access to continuing professional education (CPE) that is responsive to the needs of learners, employers and most importantly clients. There is scant attention paid to the CPE custom of community nurses, with research in the experience of island-based nurses mainly limited to the Mediterranean and under-developed islands, or of nurses working in the Scottish Isles. The community nurses in question are employed by a charity working outside the National Health Service (NHS), based on an island with a unique model of healthcare that is more medicalised and institutionalised than the United Kingdom NHS. Semi-structured, one-to-one interviews were conducted with sixteen community nurses, and two focus groups undertaken, one with nurse managers and the other with qualified nurses. Interview data were analysed using Interpretative Phenomenological Analysis, a method new to education research, and not yet recorded in relation to nurse education. Findings indicated an ageing workforce, with ageism hindering access to CPE. Geographical isolation coupled with a lack of access to tertiary education dictated CPE to fulfil professional development. Charitable status and limited CPE funding resulted in a third of nurses applying for sponsorship via local or national agencies, this was not found elsewhere in the current literature. This research contributes to the knowledge relating to nurse CPE, confirming the transferability of existing literature relating to geographical remoteness, barriers and outcomes of formal study to community nurses. It advances the current knowledge base with regard to small island infrastructure effecting access to CPE, funding formal education for nurses working outside the NHS, and silo working within the community setting. Further research is required to explore the experience of community nurses under the age of 30 years not represented within this study, who will be the future workforce when older nurses retire. These findings are of particular significance to the Jersey Health and Social Services Department who are currently redesigning the future health and social care system on the island based on a community model, nurse educators, the charity and its qualified nurse employees, and finally the island population.
358

Determinants of the initiation and duration of breastfeeding among women in Kuwait

Dashti, Manal January 2010 (has links)
Regular breastfeeding surveillance is essential to determine to what extent national breastfeeding targets are being met and how breastfeeding practices change over time. There have been irregular infant feeding studies or national surveys carried out in Kuwait so it is difficult to assess secular trends in breastfeeding practices. The objective of the Kuwait Infant Feeding Study (KIFS) was to identify the incidence and prevalence of breastfeeding up to 26 weeks postpartum among a population of women living in Kuwait and to identify the factors associated with the initiation and duration of breastfeeding. A sample of 373 women recruited shortly after delivery from four hospitals in Kuwait completed a structured, interviewer-administered questionnaire and follow-up telephone interview at 6, 12, 18 and 26 weeks postpartum. Multivariate logistic regression analysis was used to identify those factors independently associated with the initiation of breastfeeding and survival analysis was used to examine the duration of breastfeeding. In total, 92.5% of mothers initiated breastfeeding and at discharge from hospital the majority of mothers were partially breastfeeding (55%), with only 30% of mothers fully breastfeeding. Prelacteal feeding was the norm (81.8%) and less than 1 in 5 infants (18.2%) received colostrum as their first feed. Only 10.5% of infants had been exclusively breastfed prior to hospital discharge, the remainder of breastfed infants having received either prelacteal or supplementary infant formula feeds at some time during their hospital stay. At six months of age, 39% of mothers were still breastfeeding but none of the women were fully or exclusively breastfeeding. The median duration of any breastfeeding duration was 13.9 weeks. 2 Breastfeeding at discharge from hospital was independently positively associated with paternal support for breastfeeding and negatively associated with delivery by caesarean section and with the infant having spent time in the Special Care Nursery. Mothers originally from other Arab countries were more likely to initiate breastfeeding in hospital than Kuwaiti mothers. Women whose husbands worked in sales or clerical occupations and Kuwaiti national mothers were at higher risk of early breastfeeding termination. Women whose husband or own mother preferred breastfeeding, breastfed for longer than those women whose husbands or mothers preferred formula feeding or were ambivalent about how they fed the infant. Hospital-related factors including time of first feeds, type of first feed, age of introducing a pacifier and feeding on demand were significantly associated with breastfeeding duration. The results of this study indicate that while breastfeeding is almost universally initiated, very few women achieve the WHO recommendations of exclusive breastfeeding to 6 months of age. The reasons for the high use of prelacteal and supplementary formula feeding warrant further investigation. Data collected in this study will contribute to the limited breastfeeding surveillance data available for Kuwait and inform future public health policy. Hospital policies and staff training are needed to promote the early initiation of breastfeeding and to discourage the unnecessary use of infant formula in hospital, in order to support the establishment of exclusive breastfeeding among mothers in Kuwait.
359

Detection of Human Rotavirus in Southern Ontario Source Waters

Davis, Bailey Helena 08 January 2013 (has links)
As part of a larger quantitative microbial risk assessment (QMRA) study, the raw water intakes of 8 different drinking water treatment plants in Ontario were sampled for rotavirus. Group A rotavirus was detected and semi-quantified via RT-qPCR. Rotavirus was detected in 6 of 8 drinking water treatment plant raw water intakes at various sampling times during a 2 year period at estimated quantities of 0 – 513 viral genome copies/L water. As hypothesized, the virus counts showed a seasonal tendency with significant detection most likely to occur during the spring months and a correlation with turbidity measurements. To our knowledge this is the first study exploring the presence of rotavirus in Ontario source waters. With new proposed changes to the Health Canada guidelines regarding the viruses in drinking water, data on the presence of rotavirus in source waters is required for assessment of risk to public health. / Kingsclear First Nation
360

Understanding the Effects of Model Evolution Through Incremental Test Case Generation for UML-RT Models

Rapos, ERIC 27 September 2012 (has links)
Model driven development (MDD) is on the rise in software engineering and no more so than in the realm of real-time and embedded systems. Being able to leverage the code generation and validation techniques made available through MDD is worth exploring, and is the focus of much academic and industrial research. However given the iterative nature of MDD, the natural evolution of models causes test case generation to occur multiple times throughout a software modeling project. Currently, the existing process of regenerating test cases for a modified model of a system can be costly, inefficient, and even redundant. The focus of this research was to achieve an improved understanding of the impact of typical model evolution steps on both the execution of the model and its test cases, and how this impact can be mitigated by reusing previously generated test cases. In this thesis we use existing techniques for symbolic execution and test case generation to perform an analysis on example models and determine how evolution affects model artifacts; these findings were then used to classify evolution steps based on their impact. From these classifications, we were able to determine exactly how to perform updates to existing symbolic execution trees and test suites in order to obtain the resulting test suites using minimal computational resources whenever possible. The approach was implemented in a software plugin, IncreTesCaGen, that is capable of incrementally generating test cases for a subset of UML-RT models by leveraging the existing testing artifacts (symbolic execution trees and test suites), as well as presenting additional analysis results to the user. Finally, we present the results of an initial evaluation of our tool, which provides insight into the tool’s performance, the effects of model evolution on execution and test case generation, as well as design tips to produce optimal models for evolution. / Thesis (Master, Computing) -- Queen's University, 2012-09-26 14:18:50.838

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