Le syndrome d'immunodéficience acquise (SIDA) est une maladie provoquée chez l'homme par le virus de l'immunodéficience humaine (VIH), un lentivirus à ARN monocaténaire qui infecte les cellules humaines qui expriment les CD4 à leur surface. Depuis son apparition en 1982 chez l’homme, il y a eu environ 80 millions d'individus infectés dans le monde et près de la moitié d'entre eux sont déjà décédés. Aucun vaccin n'existe actuellement mais l'espérance de vie d’un grand nombre de patients est maintenant prolongée grâce au développement et la disponibilité d'un traitement antirétroviral hautement actif (HAART en anglais). En raison de la complexité des interactions hôte/pathogène liées à l'infection par le VIH-1 chez l'homme et les modèles primates non-humains actuels, le développement d’un modèle plus simple est nécessaire pour étudier et mieux comprendre les mécanismes sous-jacents de l'augmentation de la pathogenèse du VIH-1 chez l’humain. Dans ce but, un virus chimérique CAL-HIV-R1 a été construit dans notre laboratoire en échangeant les longues séquences répétées terminales (LTR) du VIH par celles du CAEV, un lentivirus caprin. Parce que ces LTR de CAEV ont un promoteur constitutif qui est indépendant du trans-activateur de la transcription, ce virus chimérique ne devrait pas subir de latence dans les cellules T CD4+ mémoire. Pour rendre son efficacité réplicative plus performante, cette chimère a subi plusieurs passages successifs sur des cellules humaines en culture. En plus de la présence de son récepteur primaire, la protéine CD4, le VIH doit interagir avec une seconde molécule co-réceptrice pour entrer dans la cellule hôte. Des clones moléculaires infectieux contenant des génomes proviraux complets de plusieurs isolats de VIH-1 ont été reçus de la banque de produits "NIH AIDS Reagent Program Repository". Trois d'entre eux, à savoir pNL4-3, p89.6 et WARO, ont été utilisés pour produire des stocks de virus après transfection des cellules de la lignée humaine HEK-293T et utilisés pour infecter d’autres lignées cellulaires telles que : 1) des cellules GHOST, utilisées pour examiner le tropisme des virus en fonction de leur utilisation des co-récepteurs et qui sont respectivement X4, X4/R5 et R5; 2) la lignée cellulaire M8166, utilisée comme cellules indicatrices du fait de ses propriétés fusogéniques, et qui sert à examiner les capacités de réplication et enfin, 3) la lignée cellulaire TZM-bl utilisée pour évaluer le titre infectieux des virus. Par ailleurs, un vaccin basé sur un vecteur ADN lentiviral chimérique, le CAL-SHIV-IN-, a été développé au laboratoire et testé chez des macaques. Dans le cadre de cette étude, un test de séro-neutralisation a été réalisé sur des échantillons de sérum des macaques vaccinés avec ce vecteur, et des animaux témoins, pour examiner la présence d'anticorps pouvant neutraliser le virus. Bien que des anticorps furent présents aucune capacité neutralisante n'a pu être détectée. / Acquired Immuno-Deficiency Syndrome (AIDS) is a disease caused by immunodeficiency viruses in human (HIV-1) and some animal species. The virus is a small enveloped particle that has a single-strand RNA genome and belongs to the lentivirus genus that belongs to the Retroviridae family. In human the virus infects and replicates mainly in cells that express the CD4 on their surface. Since its apparition in human in 1982 the virus has infected around 80 million individuals worldwide and caused the death of nearly half of them. No vaccine exists but life expectancy of near half of HIV-1-infected individuals has been now prolonged due to extensive highly active antiretroviral therapy (HAART). Because of the complexity of the host/pathogen interactions that are associated with HIV-1 infection in human and non-human primate models, a simple model system is strongly needed to ease the studies aiming at better understanding the underlying mechanisms of increased pathogenesis of HIV-1 in human. A chimeric virus CAL-HIV-R1 was created in our laboratory by exchanging the long terminal repeats (LTRs) of HIV with those of CAEV, a caprine lentivirus. Because these CAEV LTRs have a constitutive promoter, which is independent of the trans-activator of transcription, we expect that this chimeric virus should not undergo latency in memory CD4+ T cells. To increase the potency of this chimera, serial passages on cultured human cells were performed. Besides its primary receptor, CD4, HIV needs to interact with another molecule as a co-receptor. Several infectious molecular clones of HIV-1 isolates pDNAs containing the complete proviral genomes were received from the NIH AIDS Reagent Program Repository. Three of these, namely pNL4-3, p89.6 and WARO, were used to produce virus stocks following transfection in the human HEK-293T cell line and used to infect a variety of cell lines such as: 1) GHOST cells that were used to examine the tropism for the co-receptor that were X4, X4/R5 and R5 respectively; 2) M8166 a fusogenic indicator cell line to evaluate the replication competency, 3) TZM-bl to determine the infectivity titers of the viruses by scoring the blue cells enabled by infections. A vaccine based on a chimeric DNA vector, CAL-SHIV-IN-, has been developed in our laboratory and tested in macaques. A sero-neutralization assay was performed on sera of macaques, which had been vaccinated with this vector and challenged in parallel with control animals with a pathogenic virus. This assay was used to verify the presence of neutralizing antibodies, but, unfortunately none could be detected.

Online education is the fastest growing form of course delivery of higher education in the United States. It has revolutionized how students and instructors interact in the educational process. Yet students in online courses continue to experience higher attrition rates than their counterparts in traditional face-to-face classes despite the advantages offered by the technology. This study examined the impact that institutional policies and practices at community colleges in the state of Texas have had on student persistence in online courses. It also examined how institutions collect and use data in addressing students' attrition. The findings were used to identify the most effective institutional practices to share with community college systems in Texas in an effort to improve student persistence in online courses across the state. The population for the study consisted of the 50 public two-year community college and the technical college systems in the state of Texas. The study used a mixed method. A theoretical model of institutional impact on online persistence was drawn from the literature review. This model's five categories were then used to construct a survey to collect data on institutional practices and measure the effectiveness in addressing student persistence. Four college systems were identified using the survey data that best met the five categories. Interviews were then conducted at these four college systems to produce case studies of these institutions' practices and experiences with online persistence. The results highlighted the roles that institutions play in promoting student persistence in online programs. They revealed differences in the ways institutions define and track student success in online programs and the difficulty these differences pose in comparatively evaluating various institutions' programs. Results lent support to the theoretical model of institutional impact on online persistence that was developed for this study, and results yielded a proposed list of promising practices to enhance student persistence in online programs in public two-year community and technical colleges.

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Modern data intensive applications, such as multimedia systems require the ability to store and manipulate complex data. The classical Database Management Systems (DBMS), such as relational databases, cannot support these types of applications efficiently. This dissertation presents the salient features of Object Database Management Systems (ODBMS) and Persistent Programming Languages (PPL), which have been developed to address the data management needs of these difficult applications. An 'impedance mismatch' problem occurs in the traditional DBMS because the data and computational aspects of the application are implemented using two different systems, that of query and programming language. PPL's provide facilities to cater for both persistent and transient data within the same language, hence avoiding the impedance mismatch problem. This dissertation presents a method of implementing a PPL by extending the language C++ with pre-compiled classes. The classes are first developed and then used to implement object persistence in two simple applications. / Computing / M. Sc. (Information Systems)

À la recherche de ses limites, de son mode de gestion et des orientations pour son développement, sans modèles et sans références claires, le nouveau développement des villes laotiennes dans de tel processus, est mal maîtrisé. Il explicite des difficultés certaines dans la construction des cadres de vie de qualité. Il met aussi en évidence la désolidarisation de la ville par rapport à ses structures primitives composées par ses racines historiques : ses habitants et leurs pratiques, ses centres anciens en tant qu'espaces hérités et référencés. À partir des années 1995 et 2000, espaces ou centres historiques sont modifiés peu à peu parallèlement à l'apparition de nouveaux quartiers, aboutissant à une recomposition spatiale, d'où la difficulté à identifier les centres historiques et à délimiter le territoire urbain lui-même. Les liens entre les villes qui se développent et leurs espaces anciens qui fonctionnaient jusqu'alors comme leurs lieux de référence, de cohérence sociale et de structuration spatiale, sont fragilisés. Les notions de centre historique et d'habitat ancien et le mode d'habiter la ville ont été, pour ainsi dire, altérés, corollairement à l'altération de la notion même de ville. La ville, son espace, ses composants sociaux, politiques et symboliques, en tant que matrice structurante et identitaire, semblent être aujourd'hui reniés ou négligés. À ce constat, développé dans la première partie de la thèse, sont apposés dans la seconde partie les regards introspectifs (dans le fondement culturel et humain qui a forgé les caractéristiques des établissements lao) et rétrospectifs (dans l'histoire et le temps de la construction spatiale) sur l'espace des villes laotiennes. Ces regards permettent de déceler la période qui s'étend entre 1975 et 1990 comme responsable des ruptures. Le redéploiement idéologique du nouveau régime, accompagné de nouveaux dispositifs spatiaux intervenus dans cette période, aurait apporté des transformations importantes dans la perception de la ville et de son histoire, dans la pratique spatiale, dans la manière de gérer et de développer la ville. En négligeant les centres historiques et leurs principes fondateurs, on néglige en même temps les facteurs pédagogiques des espaces hérités. Les pouvoirs publics et les habitants occupaient respectivement l'espace, durant cette période, pour les uns, suivant une projection idéologique de collectivisation des biens, et pour les autres, suivant une pratique d'occupation sans acte d'appropriation. Entre la période où les villes évoluaient sans trop s'écarter de leurs matrices de fondation et les moments où elles se développent dans une profonde recomposition avec difficultés et handicaps, caractérisant la période actuelle, les années 1975 et les années 1980 semblent constituer une période transitoire, illustrée par la notion de “ ville absente ” et par le phénomène de “ squattérisation publique. ”La réflexion menée dans cette recherche est de démontrer que les difficultés de la période actuelle sont liées à la période transitoire, que la stratégie de développement urbain et territorial en cours doit probablement être mise en œuvre en revisitant les expériences de ces années transitoires. Ce qui avait été négligé, telles la notion de ville comme composant hérité de l'histoire, la notion de citoyen habitant de la ville, la notion de création, de gestion et de partage des espaces, devraient probablement être replacée au cœur des préoccupations des décideurs et des habitants. Dans ce nouveau contexte régional, c'est aussi en interrogeant ses propres données endogènes ou endogénisées tout au long de l'histoire, que le Laos pourrait constituer ses modèles d'espace et de développement adaptés et durables / Today's regional construction of the South-East Asia, cities are faced with accelerated development, their economic, cultural and human spaces are recomposed and restructured. Their trajectories of development are also diversified. Beginning in the mid 1990s and has intensified since 2000s, the Laotian cities began a new urban period, which question not only the future but also the past: how does Laos live its regional and especially its local integration? In search of its limits and mode of management and in search of the direction for its development, without models and clear references, the new development of Laotian cities is badly handled. It clarifies certain difficulties in building quality of life. It also highlights the separation of the city with regard to its primitive structures consisted by its historic roots: its inhabitants and their practices, its old centers as inherited and referenced space. From 1995 and 2000, spaces or historical centers are modified at the same time the new area appears, ending in a spatial reorganization, causing difficulties in identifying the historic centers with the urban territory. The links between the cities, which develop in progress with their former spaces, worked until their places of social reference, coherence and spatial structuring are weakened. As the city changes, the notions of historic centers, the old housing environments and the mode to live in the city were altered. The city, its space, social, economic, political and symbolic components, as structuring and identity matrix, seem to be denied or neglected today. This report developed in the first part of the thesis, are affixed in the second part the introspective (in the cultural and human foundation of the space which forged establishments lao and their characteristics) and retrospective regards (in the history and the time of the construction of the space) to the space of the Laotian cities. These regards allow revealing periods extending between 1975 and 1990 as something in charge of the break. The ideological redeployment of the new political regime accompanied with new spatial devices intervened for this period would have brought the important transformations in the perception of the city and its history, in the spatial practice, the way of managing and of developing the city. Neglecting the historic centers and their founding theory, we neglect at the same time the educational value of the inherited spaces. Public authorities and inhabitants occupied respectively the spaces, during this period: for some, following an ideological projection in collectivization of the properties, and for others, according to a practice of occupation without act of appropriation. Between the period when cities evolved without moving away from their matrices of foundation and when they have to develop a profound reorganization with difficulties and handicaps, characterizes the current period. 1975s and 1980s seem to constitute a period of transition illustrated by the notion of "absent city" and by the phenomenon of "public squat". The reflection led in this research is to demonstrate that dificulties of actual period are linking with the transition period, that strategy of urban development of today has to be implemented by revisiting the experiments of the period of transition. What had been neglected, such the notion of the city with its components inherited from history, the citizen living in the city, the creation, management and sharing of spaces and territories, should probably be replaced in the concerns of the policies (decision-makers) and of the inhabitants. In this new regional context, in questioning also its own endogenous data, or internalized data all along history, that Laos will establish its models of space and development in an adapted and long-lasting way

Modern data intensive applications, such as multimedia systems require the ability to store and manipulate complex data. The classical Database Management Systems (DBMS), such as relational databases, cannot support these types of applications efficiently. This dissertation presents the salient features of Object Database Management Systems (ODBMS) and Persistent Programming Languages (PPL), which have been developed to address the data management needs of these difficult applications. An 'impedance mismatch' problem occurs in the traditional DBMS because the data and computational aspects of the application are implemented using two different systems, that of query and programming language. PPL's provide facilities to cater for both persistent and transient data within the same language, hence avoiding the impedance mismatch problem. This dissertation presents a method of implementing a PPL by extending the language C++ with pre-compiled classes. The classes are first developed and then used to implement object persistence in two simple applications. / Computing / M. Sc. (Information Systems)

Research suggests that belonging to multiple group memberships before and after life transitions promotes resilience by helping people maintain their well-being compared to those with fewer group memberships. Although group memberships are of key importance for well-being and adjustment to change, the influence of athletes’ group memberships on their well-being remains largely unexplored, despite the numerous transitions they face in sport. Furthermore, no research to date has assessed the effects of group memberships on performance, and little research has assessed the potential mechanisms through which group memberships produce beneficial effects on outcomes. These ideas were explored in this thesis. Two studies within this thesis adopted a longitudinal approach, using questionnaires to examine the effects of players’ group memberships on well-being after a sporting transition. Study 1 focused on team and club transitions for university students and measured changes in well-being across a three month period; Study 2, focused on programme transitions in elite cricket and measured changes in well-being across a two year period. Study 2 also examined whether the beneficial effects of group memberships extended to performance. Both studies demonstrated that players with multiple group memberships before and after transition generally experienced greater well-being after transition. Study 2 also showed that multiple group memberships had beneficial implications for performance. However, when the recency of the transition was taken into consideration, significant interactions between group memberships and time since the transition generally revealed that the beneficial effects were most pronounced for those who had recently transitioned into the clubs, teams, and programmes. Furthermore, both studies revealed that players with multiple group memberships before a transition were better able to maintain these group memberships across the transition (i.e., lose fewer groups) and more likely to identify highly with the new club, team, or programme (i.e., join new groups). Although Study 1 failed to uncover evidence of the processes underpinning these effects, Study 2 provided some evidence that identification with the new group, and (to a lesser extent) personal identity strength, appeared to be important potential mediators of the group membership effects. In Study 3, an experimental approach was employed to investigate whether changing athletes’ group memberships is associated with improvements in performance and persistence in a golf-putting task. To do this, the study manipulated the number of group memberships participants reflected on (i.e., control, one, or five groups) and assessed the effects this had on their performance and persistence (as an indicator of resilience). Results revealed that participants who were asked to reflect on five groups that they belonged to showed a greater improvement in their performance after receiving the group manipulation than those who reflected on one group and those in the control group condition. Furthermore, those who reflected on groups they belong to (whether one, or five) showed more persistence following false failure feedback than those who did not. Although potential mediating mechanisms were measured, there was no evidence that any of these processes accounted for the beneficial impact of group memberships. Overall, the results from this thesis demonstrate that multiple group memberships can promote resilience by making important contributions to athletes’ well-being, performance, and persistence. Thus, athletes should be encouraged to increase the number of group memberships they belong to as this may provide an important psychological resource during times of change.

Statins are commonly used for treating the elevation of lipids in the blood stream, also known as hyperlipidemia. Statins are considered to be an economical and effective way to achieve desirable long-term health outcomes for hyperlipdemic patients, however, ensuring adequate adherence to statin medications is often difficult as hyperlipidemia is an asymptomatic condition and patients sometimes fail to recognize the importance of being adherent to their statin medications. The purpose of this study was to evaluate impact of enrollment under Medicaid and Medicare Part D and patient out-of-pocket costs on patient statin adherence, persistence, and mean number of gap days per claim. A retrospective claims database was used in this study to conduct repeated measures analyses on statin prescription claims from independent community pharmacies in Texas. The pre-period in this study extended from January 1, 2005 to September 30, 2005 (Medicaid period) and the post-period extended from January 1, 2006 to September 30, 2006 (Medicare period). The study population consisted of dual-eligible beneficiaries in Texas who had at least two stain claims in the pre and post-periods each. The final study population comprised of 1734 Texas dual-eligible beneficiaries with 6064 statin claims during the pre-period and 7956 claims during the post-period. Patients had an average of 3.49 statin claims during the pre-period and 4.58 statin claims during the post-period. Patients were dispensed an average of 57.34 days of drug supply per claim during the pre-period and 42.02 days of drug supply per claim during the post-period. The results from this study showed that out-of-pocket costs for patients increased from $0.39 per claim under Medicaid to $13.36 per claim under Medicare Part D. Patient adherence to statins was assessed by calculating medication possession ratio (MPR). The results showed that mean patient MPR increased from 75.71 percent under Medicaid to 79.37 percent under Medicare. Results from generalized estimating equations showed that odds of being adherent (i.e., MPR ≥ 80 percent) to statins increased by 36 percent when patients were covered under Medicare Part D. Linear mixed model analysis showed that MPR increased by 3.66 percent when patients were covered under Medicare Part D compared to Medicaid. Also, patient MPR was found to increase by 0.13 percent when patient out-of-pocket payment increased by $1.00. Patient persistence was calculated by measuring gaps in therapy and patients with a gap of 60 or more days were considered to have discontinued therapy. Patients were found to be persistent to their drug therapy for an average of 151.76 days under Medicaid and 159.75 days under Medicare. Linear mixed model analysis showed that patient persistence increased by 7.99 days when patients were enrolled under Medicare Part D compared to Medicaid. Days of persistence was also found to increase by 0.41 days when patient out-of-pocket costs increased by $1.00. Mean number of gap days per claim during the Medicaid period was 11.91 days and decreased to 8.38 days during the Medicare period. Linear mixed model analysis showed that mean number of gap days per claim decreased by 3.52 days when patients were enrolled under Medicare Part D compared to Medicaid. Mean number of gap days in therapy were found to decrease by 0.10 days when patient out-of-pocket costs increased by $1.00. The results of this study showed that implementation of Medicare Part D resulted in an increase in MPR and persistence and a decrease in mean number of gap days per claim for Texas dual-eligible beneficiaries. The results also suggest that increased out-of-pocket costs under Medicare Part D may not have had a negative impact on statin drug utilization by dual-eligible beneficiaries in Texas. / text

The contamination of inland surface water by point and nonpoint sources is a widespread human health concern. To address this problem, a thorough understanding of the sources and persistence of this pollution is necessary. Using fecal indicator bacteria (FIB) as a surrogate for enteric pathogens, the Environmental Protection Agency (EPA) and state agencies have developed surface water quality standards. If a segment does not meet these standards, a Total Maximum Daily Load (TMDL) must be developed for the watershed to identify sources of bacterial pollution. Currently, FIB pollution is the leading pollution type addressed by TMDLs in the country. One source of FIB identified in TMDLs is colonies of birds roosting under bridges. It has been proposed that the birds’ feces can augment the FIB concentrations downstream of bridges. In this year-long study of Bull Creek in Austin, Texas, it was determined that the concentrations of Escherichia coli and fecal coliform downstream of a bridge were significantly greater when migratory cliff swallows were nesting under the bridge. The downstream concentrations of both FIB exceeded contact recreation standards. Data also suggest that FIB from the feces could be swept into the stream by runoff from storm events. No enterococci loading was observed in conjunction with the swallows. This study also investigated the affects of sediment resuspension on surface water FIB concentrations and the persistence of FIB in shady, inland streams. The resuspension of sediments with attached FIB could also increase the FIB concentration in the water column and increase its persistence. The results of reactor-based experiments demonstrated that the concentration of E. coli in water from an effluent-dominated stream increased by a factor of 3 when riverine sediments were resuspended and exceeded single sample standards for contact recreation, suggesting sediments as a reservoir of E. coli. Additionally, concentrations of E. coli decreased by approximately 90% and 70% over 2 days in reactors containing stream water and sediment-laden stream water, respectively. / text

The literature on regime persistence in the Arab world, particularly when it comes to the monarchies, has missed many crucial elements. Specifically, the role of the military within the elite coalition and the factors that lead to variation on this variable have not been adequately studied. In this report, two cases of persistent monarchies – Morocco and Jordan - will be examined. This study will focus on the development of the military establishments in these two cases, as well as their current state of civil-military relations. Using an institutionalist approach, the study finds that civil-military relations in both regimes is a direct outcome of the monarchy’s role, which, in turn, rests on three factors: the historical legacy of the monarchy in state formation, the appeal of the monarch to a large proportion of the population, and the institutional mechanisms utilized by the monarchy to maintain control over their military establishments. The monarchical role in the development of the military subordinates the armed forces, as well as lessens their professionalization as they become less representative and more politicized institutions. Subordination of the military as a strategy of the monarchy is thus highlighted as an important variable in the persistence of this type of authoritarian regime. / text