The process of transition to college is complex and has received attention from many scholars (e. g. Baker & Siryk, 1999; Beal & Noel, 1980; Choy, Horn, Nunez, & Chen, 2000; Gaither, 1999; Paul & Brier, 2001; Tinto, 1993). Transition impacts persistence in college, hence retention rates (Tinto, 1993). As a result, postsecondary institutions have developed models of transition. In one such model, first year students experience transition in four domains; academic, social, personal-emotional, and attachment (Baker & Siryk, 1999). Past studies have explored transition from the perspective of majority versus minority student experiences (Allen, 1992; Hurtado, Carter, Spuler, 1996; Rodriquez, Guido-DiBrito, Torres, & Talbot, 2000) as well as male versus female experiences (American Association of University Women, 1992; Fassinger, 1995; Gablenick, MacGregor, Matthews, & Smith, 1990). The current body of literature fails to adequately represent transition issues for non-majority students, however. For example, additional research is needed to compare experiences among minority groups (e.g., African American v. Hispanic v. Native American). In addition, studies that explore the relationship between retention and transition for minorities and women are needed. The current study was designed to examine transition experiences of minorities and women attending predominantly White institutions. In addition, the study addressed the link between transition and retention to second semester and the second year of college. The Student Adaptation to College Questionnaire (SACQ) (Baker & Siryk, 1999) measures the transition experiences of students in college. In the current study, the author administered the SACQ to minority students in their first year at a predominantly White institution. The participants' responses were analyzed to determine if differences existed in transition experience by race or sex. Follow-up information was collected to explore whether students who had higher transition levels were more likely to return to college for the second semester and the second year. Results revealed that minority students made successful transitions during the first year as well as developed a strong attachment to the institution and higher education. However, there were no significant differences in the transition experiences of the participants by race or sex. When examining the relationship between transition and retention, findings show that students who left had high or medium transition levels. / Ph. D.

Background: A growing population of youth with medical complexity (YMC) are surviving into adulthood and being forced to transition from pediatric to adult health care. YMC and their families face significant challenges during this transition, putting them at risk for service fragmentation, inadequate care, and negative health outcomes. Existing interventions to support transition continue to have limited benefits for this group, demonstrating a clear need for tailored supports, informed by the perspectives of YMC and their families. Currently, these families’ transition experiences are poorly understood in the Canadian context. Thus, the aim of this dissertation was to holistically examine the experiences of families of YMC with the transition to adult care in Ontario. Methods: This sandwich thesis consists of: 1) a meta-ethnography synthesizing qualitative literature about the experiences of YMC and their families during the transition to adulthood; and 2) a patient-oriented qualitative case study exploring: i) how families of YMC adapt to the transition to adult care; ii) the influence of contextual factors; and iii) family recommendations for support. Findings: Transition impacts nearly all aspects of the youth’s and family’s lives. Families encounter numerous challenges in their pursuit of a good future and they “survive” by advocating, making sacrifices, and persisting despite inequities. Furthermore, families’ experiences are shaped by the complex interplay of personal and environmental factors. Conclusion: Implications for nursing practice, health care provider education, and health policy focus on: supporting nurses to provide instrumental and psychological support to families; building capacity in primary care (e.g., through nurse-led models of care); training health professionals on complex care management; and advocating for system-wide strategies to improve health care transition. Future research should prioritize the co-design and evaluation of interventions to address families’ information and emotional needs and training initiatives to facilitate the implementation of recommendations into practice. / Thesis / Doctor of Philosophy (PhD) / Youth with medical complexity have serious illness and intensive care needs. Recent advances in technology have led to more of these youth living into adulthood and moving to adult health care. The transition to adult care puts their health at risk and is highly stressful for their families. Currently, little is known about how these families cope with this transition and what help they need. This thesis aims to address these gaps by reviewing existing research and interviewing youth and families about their experiences. Findings show that the transition to adult care greatly affects many parts of the youth’s and family’s lives. Families cope with these changes by advocating, making sacrifices, and persisting in the face of inequities. Study findings can help guide nurses, other health care providers, and policy makers to better support these youth and families in their transition to adult care.

A task force commissioned by President Obama overhauled the U.S. Military Transitioning Program (MTP) in 2012-2013. U.S. veterans have continued to struggle with military transitions following the MTP restructuring. The purpose of this phenomenological inquiry was to explore the critical success factors of the MTP after the redesign based on perceptions of 20 military officers intending to transition to the civilian sector in the National Capital Region. The problem studied was that there was no indication that the redesigned MTP was effective in helping officers transition to the civilian workforce. The study included 3 research questions and semistructured interviews were the primary means to collect data. Schlossberg's 4S transition theory, identity theory, and work-role transition theory comprised the conceptual framework. Data analysis included content analysis and the Stevick-Colaizzi-Keen Method. The findings in this study emphasized the importance of several critical success factors of the redesigned MTP: its focus on transition preparedness, its practical applications, individual counseling, and the knowledge and education obtained while attending the MTP. Senior leaders responsible for the MTP can benefit from this study by understanding the challenges the participants encountered while attending the MTP. Implications for social change include informing U.S. government leaders of the MTP of the need for continued improvements to MTP processes, services, and programs to aid transitioning veterans seeking civilian employment.

A task force commissioned by President Obama overhauled the U.S. Military Transitioning Program (MTP) in 2012-2013. U.S. veterans have continued to struggle with military transitions following the MTP restructuring. The purpose of this phenomenological inquiry was to explore the critical success factors of the MTP after the redesign based on perceptions of 20 military officers intending to transition to the civilian sector in the National Capital Region. The problem studied was that there was no indication that the redesigned MTP was effective in helping officers transition to the civilian workforce. The study included 3 research questions and semistructured interviews were the primary means to collect data. Schlossberg's 4S transition theory, identity theory, and work-role transition theory comprised the conceptual framework. Data analysis included content analysis and the Stevick-Colaizzi-Keen Method. The findings in this study emphasized the importance of several critical success factors of the redesigned MTP: its focus on transition preparedness, its practical applications, individual counseling, and the knowledge and education obtained while attending the MTP. Senior leaders responsible for the MTP can benefit from this study by understanding the challenges the participants encountered while attending the MTP. Implications for social change include informing U.S. government leaders of the MTP of the need for continued improvements to MTP processes, services, and programs to aid transitioning veterans seeking civilian employment.

De nombreux systèmes complexes soumis à un ajout continu d'énergie réagissent à cet ajout par une accumulation de tension au cours du temps, interrompue par de soudaines libérations d'énergie appelées avalanches. Récemment, il a été remarqué que plusieurs propriétés élémentaires de la dynamique d'avalanche sont issues de processus de relaxation ayant lieu à une échelle microscopique, processus qui sont négligés dans la plupart des modèles. Lors de ma thèse, j'ai étudié deux modèles classiques d'avalanches, modifiés par l'ajout d'une forme de relaxation la plus simple possible. Le premier système est une interface viscoélastique tirée à travers un milieu désordonné. En champ moyen, nous prouvons que l'interface a un comportement périodique caractérisé par une nouvelle échelle temporelle (émergente), avec des avalanches qui touchent l'ensemble du système. Le calcul semi-analytique de la force de friction agissant sur la surface donne des résultats compatibles avec les expériences de friction classique. En dimension finie (2D), les événements touchant l'ensemble du système (trouvés en champ moyen) deviennent localisés, et les simulations numériques donnent des résultats en bon accord avec plusieurs caractéristiques importantes des tremblements de terre, tant qualitativement que quantitativement. Le second système incluant également une forme très simple de relaxation est un modèle jouet d'avalanche : c'est la percolation dirigée. Dans notre étude d'une variante non-markovienne de la percolation dirigée, nous avons observé que la classe d'universalité était modifiée mais seulement partiellement. En particulier, un exposant change de valeur tandis que plusieurs relations d'échelle sont préservées. Cette idée d'une classe d'universalité étendue, obtenue par l'ajout d'une perturbation non-markovienne offre des perspectives prometteuses pour notre premier système. / Many complex systems respond to a continuous input of energy by an accumulation of stress over time, interrupted by sudden energy releases called avalanches. Recently, it has been pointed out that several basic features of avalanche dynamics are induced at the microscopic level by relaxation processes, which are neglected by most models. During my thesis, I studied two well-known models of avalanche dynamics, modified minimally by the inclusion of some forms of relaxation. The first system is that of a viscoelastic interface driven in a disordered medium. In mean-field, we prove that the interface has a periodic behaviour (with a new, emerging time scale), with avalanche events that span the whole system. We compute semi-analytically the friction force acting on this surface, and find that it is compatible with classical friction experiments. In finite dimensions (2D), the mean-field system-sized events become local, and numerical simulations give qualitative and quantitative results in good agreement with several important features of real earthquakes. The second system including a minimal form of relaxation consists in a toy model of avalanches: the Directed Percolation process. In our study of a non-Markovian variant of Directed Percolation, we observed that the universality class was modified but not completely. In particular, in the non-Markov case an exponent changes of value while several scaling relations still hold. This picture of an extended universality class obtained by the addition of a non-Markovian perturbation to the dynamics provides promising prospects for our first system.

La lumière est indispensable à la survie des plantes via le processus photosynthétique, pourtant les plantes doivent s'adapter à différentes conditions environnementales où la quantité et la qualité de la lumière peuvent être non optimales pour la photosynthèse. Cela peut provoquer des dégâts photo-induits par formation d'espèces réactives de l'oxygène (ROS), qui sont dangereux pour la plante. Pour limiter la formation des ROS, les plantes mettent en place une régulation importante qui est la dissipation thermique de l'énergie absorbée en excès, appelé Non photochemical quenching (NPQ). Il est connu que la protéine PsbS joue le rôle clé de senseur du pH bas du lumen thylacoïdal, qui est le signal initial pour activer le NPQ. Dans le contexte de cette thèse, on propose d'étudier l'hypothèse que l'absence de la protéine PsbS (diminué NPQ) pourrait augmenter la croissance et la productivité des plantes en conditions contrôlées de faible lumière par l'éminilation de la protéine PsbS chez Arabidopsis thaliana et chez la tomate. Les résultats obtenus indiquent qu'en lumière faible les plantes mutantes montrent une augmentation du rendement de photosystème II conduisant une croissance et un nombre de fleurs significativement augmentés par rapport aux plantes sauvages.De plus, une autre régulation de la photosynthèse, nommée « transitions d'état », est importante pour optimiser la photosynthèse en réponse aux variations de la quantité et de la qualité de la lumière, grâce à la migration réversible des antennes collectrices d'énergie LHCII phosphorylées du PSII au PSI, c'est aussi étudié dans ma thèse. / Light is indispensable for plant survival, but plants have to cope with different environmental situations where light quantity and quality can be not optimal for photosynthesis. This can cause photodamage due to the formation of harmful reactive oxygen species (ROS). To limit ROS formation, plants developed a mechanism important as the dissipation of excess absorbed energy as heat and is called Non Photochemical Quenching (NPQ). The PsbS protein plays the key role of sensor of the low lumenal pH, the signal to activate NPQ. In this thesis, we proposed and investigated the hypothesis that PsbS absence (NPQ decrease) would improve growth under controlled low light upon elimination of the PsbS in Arabidopsis and tomato plants. Results showed that the increase of photosystem II yield in mutant plants leaded to a significant improvement of growth and flower number in mutants as compared with wild type plants under low light, suggesting that this mutation could be useful to improve plant performances in controlled conditions where light is strongly limiting. In addition, another photosynthetic regulation, called “state transitions”, which is important to optimize photosynthesis under variable light for intensity and quality thank to reversible migration of phosphorylated light harvesting complexes LHCII from PSII to PSI also investigated in my thesis.

Background: The challenge of research in resource-poor settings remains a profound concern and is closely linked to African social development. Work of this thesis spans the end of apartheid and first decade of the democratic era in South Africa, along with emergence of the HIV/AIDS pandemic. It also covers the founding decade of the INDEPTH Network. Aims: Through appraising health and population research in a rural southern African sub-district over the past decade, to evaluate the utility of health and socio-demographic surveillance in rural African settings for: • capturing the dynamics of health, population and social transitions • supporting a mix of research designs, and • contributing to policy and programme development and evaluation. To extend this appraisal by examining the multi-site opportunities offered by the INDEPTH Network. Methods: Work was sited in the Agincourt sub-district, a heavily populated border area of rural north-eastern South Africa. Health and socio-demographic surveillance, introduced in 1992, involved prospective follow-up of the entire sub-district population of 70,000 people (including some 30% Mozambican immigrants) who lived in 11,700 households and 21 villages. Annual census rounds systematically updated household membership and recorded all vital events (births, deaths and migrations) since the previous census. A maternity history was asked of women of reproductive age and a verbal autopsy carried out on all deaths registered. The resulting ‘data and research platform’ – a core feature of all INDEPTH field sites – provided data for computation of trends in vital events and supported an extensive interdisciplinary project portfolio. The population under surveillance can be disaggregated into cohorts selected by age, sex or other criteria. Analyses are possible at multiple levels (individual, family/household or neighborhood) and can include socioeconomic factors. Findings: The Agincourt community experienced a serious worsening of mortality among most age-sex groups, rapidly declining fertility to near replacement level, and changing patterns of labour migration. This resulted in major changes in population structure and household composition. The rising burden of chronic disease involved both chronic infectious illness (HIV/AIDS and tuberculosis) and non-communicable disorders (such as stroke and related vascular disease). The burden of illness requiring chronic care increased disproportionately to that needing acute care. Potential contributions of field sites based on health and socio-demographic surveillance to local and national health policy are considerable yet remain underexploited. Interpretation: Rural South and southern Africa is in the midst of multiple, interrelated transitions with implications for health, social and development sectors. Health and socio-demographic surveillance systems are effective research instruments that can capture the rapidly-changing dynamics of health and social transitions in developing settings. Similarly, they can support a range of observational and intervention study designs including policy evaluations. The INDEPTH Network should boost much-needed comparative research; yet singly, and as a group, many of these sites have yet to fulfil their undoubted potential.

No description available.

Th.--Sci.--Bordeaux 1, 1984. N°: 802.

Temporally developing direct numerical simulations (T-DNS) are performed and validated for bypass transition of a zero pressure gradient flat plate boundary layer to understand the interplay between pressure-strain terms and flow instability mechanisms, and to propose and validate a phenomenological hypothesis for the identification of a robust transition onset marker for use in transition-sensitive Reynolds-averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) simulations. Results show that transition initiates at a location where the slow pressure-strain term becomes more dominant than the rapid term in the pre-transitional boundary layer region. The slow pressure strain term is responsible for the transfer of turbulence energy from the streamwise component to other components while the rapid pressure strain term counteracts with the slow term in the pre-transitional regime before transition onset akin to a shear sheltering like effect. The relative magnitudes of the slow and rapid terms thus provide a basis for the development of physically meaningful large-scale parameters that can be used as a transition onset marker for Reynolds averaged Navier-Stokes RANS simulations.