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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.
231

Women's subjective and objective health over time : the role of psychosocial conditions and physiological stress responses

Mellner, Christin January 2004 (has links)
<p>Today, health problems are likely to have a complex and multifactorial etiology, whereby psychosocial factors interact with behaviour and bodily responses. Women generally report more health problems than men. The present thesis concerns the development of women’s health from a subjective and objective perspective, as related to psychosocial living conditions and physiological stress responses. Both cross-sectional and longitudinal studies were carried out on a representative sample of women. Data analysis was based on a holistic person-oriented approach as well as a variable approach. In Study I, the women’s self-reported symptoms and diseases as well as self-rated general health status were compared to physician-rated health problems and ratings of the general health of the women, based on medical examinations. The findings showed that physicians rated twice as many women as having poor health compared to the ratings of the women themselves. Moreover, the symptom ”a sense of powerlessness” had the highest predictive power for self-rated general health. Study II investigated individual and structural stability in symptom profiles between adolescence and middle-age as related to pubertal timing. There was individual stability in symptom reporting for nearly thirty years, although the effect of pubertal timing on symptom reporting did not extend into middle-age. Study III explored the longitudinal and current influence of socioeconomic and psychosocial factors on women’s self-reported health. Contemporary factors such as job strain, low income, financial worries, and double exposure in terms of high job strain and heavy domestic responsibilities increased the risk for poor self-reported health in middle-aged women. In Study IV, the association between self-reported symptoms and physiological stress responses was investigated. Results revealed that higher levels of medically unexplained symptoms were related to higher levels of cortisol, cholesterol, and heart rate. The empirical findings are discussed in relation to existing models of stress and health, such as the demand-control model, the allostatic load model, the biopsychosocial model, and the multiple role hypothesis. It was concluded that women’s health problems could be reduced if their overall life circumstances were improved. The practical implications of this might include a redesign of the labour market giving women more influence and control over their lives, both at and away from work. </p>
232

Assessment of Intra- and Inter-individual Variability of Outcome Measures in Ankylosing Spondylitis and the Efficacy and Adverse Effects of Anti-TNF Therapy

Maxwell, Lara J 05 July 2011 (has links)
Ankylosing spondylitis (AS) is a chronic, inflammatory rheumatic disease that has a highly variable disease course. Three biologic agents, adalimumab, etanercept, and infliximab, have been developed for the treatment of AS. We conducted three studies: 1) an exploratory analysis of a year-long longitudinal dataset to gain insight into the variability of disease activity, physical function, and well-being and to explore the relationship between these outcome measures; 2) a systematic review of the available evidence for the efficacy of biologic treatment; 3) a systematic review of potential adverse effects of this treatment. We found that repeated measures of disease activity, function and well-being fluctuate considerably between patients, with complex patterns occurring over time within patients. There was mostly high quality evidence that these biologics are efficacious against placebo. We did not find evidence of an increase in serious adverse events or serious infections from short-term randomized controlled trials.
233

Duration Data Analysis in Longitudinal Survey

Boudreau, Christian January 2003 (has links)
Considerable amounts of event history data are collected through longitudinal surveys. These surveys have many particularities or features that are the results of the dynamic nature of the population under study and of the fact that data collected through longitudinal surveys involve the use of complex survey designs, with clustering and stratification. These particularities include: attrition, seam-effect, censoring, left-truncation and complications in the variance estimation due to the use of complex survey designs. This thesis focuses on the last two points. Statistical methods based on the stratified Cox proportional hazards model that account for intra-cluster dependence, when the sampling design is uninformative, are proposed. This is achieved using the theory of estimating equations in conjunction with empirical process theory. Issues concerning analytic inference from survey data and the use of weighted versus unweighted procedures are also discussed. The proposed methodology is applied to data from the U. S. Survey of Income and Program Participation (SIPP) and data from the Canadian Survey of Labour and Income Dynamics (SLID). Finally, different statistical methods for handling left-truncated sojourns are explored and compared. These include the conditional partial likelihood and other methods, based on the Exponential or the Weibull distributions.
234

The development of addiction-prone personality traits and substance use behaviours in biological and adoptive families

Franco Cea, Nozomi 21 April 2017 (has links)
Substance use behaviours have been viewed as the end products of a combination of influences. Numerous theories for working with substance use behaviour utilizing a multi-systemic approach have been proposed. In this project, an effort was made to control for limitations and problems that have often beset previous studies utilizing such an approach. The overall objective of the current project was to test, using a multi-systemic approach, the ability of the family socialization framework to explain the development of substance use patterns in youth and young adults. The central hypothesis of this project was that family socialization factors (contextual factors) affect and predict the development of an offspring’s personality (individual factors) and substance use behaviour. The behavioural genetic approach (i.e., the adoption design) was utilized to examine the genetic and environmental impacts on associations between factors. This project used secondary data analyses of general population data to examine the links between aspects of the family environment, personality, and substance use patterns. The Vancouver Family Survey data set used here contained information on fathers, mothers, and offspring from 405 families (328 biological and 77 adoptive) at two points in time. The development of personality and substance use behaviours over time, and associations with family socialization factors, were examined through three studies. Study 1 focused on the associations between offspring’s perspectives of fathers’ and mothers’ parental socialization and offspring’s polysubstance use. Study 2 investigated the development of addiction-prone personality characteristics and the predictive effects of family socialization and demographic variables on these characteristics. Study 3 explored the subscales of the Addiction-Prone Personality scale: impulsivity/recklessness, sensation seeking, negative view of self, and social deviance proneness. The descriptive characteristics of each subscale and changes in subscale scores over time were investigated. Also examined were transgenerational associations on these subscales, and potential relationships between personality subscales and choice of substance. The results of this project suggest that family socialization may be linked with both substance use behaviour and personality development over time. Nurturing family socialization is negatively associated with the development of addiction-prone personality characteristics. It is also negatively associated with the development of substance use behaviours. These results are consistent with previous studies utilizing a family socialization framework. The findings supporting the family socialization framework are very encouraging for the field of child, youth, and family-related practice. Some of the limitations of the current project, implications of the findings, and future research directions are discussed. / Graduate
235

Le développement de la personnalité de l'homme de l'adolescence au milieu de la vie : approches centrées sur les variables et sur les personnes

Morizot, Julien January 2003 (has links)
Thèse diffusée initialement dans le cadre d'un projet pilote des Presses de l'Université de Montréal/Centre d'édition numérique UdeM (1997-2008) avec l'autorisation de l'auteur.
236

Characterization of the neurotrophic factor Brain-Derived Neurotrophic Factor (BDNF) in intestinal smooth muscle cells

Alqudah, Mohammad 16 April 2013 (has links)
Brain-derived neurotrophic factor (BDNF) belongs to the neurotrophin family of secreted proteins, which include in addition to BDNF, nerve growth factor (NGF) and neurotrophin 3-6 (NT-3-6). BDNF mediates its functions by activating two cell surface receptors, pan-neurotrophin receptor (P75NTR) and tropomyosin-related kinase B (TrkB) and their downstream intracellular cascades. BDNF is best known for its role in neuronal survival, regulation of neuronal differentiation, migration and activity-dependent synaptic plasticity. However, BDNF is widely expressed in non-neuronal tissues as well. The localization and the function of BDNF in intestinal smooth muscle cells (SMCs) are not well defined. Thus, the main purpose of the present study was the identification and characterization of BDNF in intestinal SMCs. Using xviii biochemical and molecular techniques, we have demonstrated in this study that BDNF is synthesized and released in rabbit intestinal longitudinal SMCs cultures. Furthermore, gut neuropeptides, Pituitary Adenylate Cyclase Activating Peptide (PACAP) and substance P (SP) increased BDNF expression and release in SMCs cultures after 24 hrs and 48 hrs incubation. We have also shown that intracellular Ca2+ levels are essential for SP stimulation of BDNF expression and secretion. Lastly, we have demonstrated that exogenous BDNF enhanced carbachol (CCh)-induced contraction of isolated longitudinal muscle strips, and this was inhibited by preincubation with TrkB inhibitor K252a and PLC inhibitor U73122 sugesting that BDNF sensitize longitudinal SMCs to CCh by activating PLC pathway, which is normally absent in those muscle cells. These results provide new insight into the mechanisms of neurotrophin (BDNF) modulation of gut function, which may lead to new therapeutic avenues for treatment of gastrointestinal disorders, and explain some of the pathological changes associated with inflammation such as hypercontractility associated with gut infection or IBD.
237

LONGITUDINAL RELATIONS BETWEEN PARENTAL MESSAGES SUPPORTING FIGHTING AND AGGRESSIVE BEHAVIOR IN EARLY ADOLESCENCE: THE MODERATING ROLE OF POSITIVE PARENTING PRACTICES

Carlson, Megan M. 01 January 2016 (has links)
The prevalence of physical aggression increases during adolescence and is associated with negative health outcomes. It is important to identify risk and protective processes for adolescent aggression in the context of the parent-adolescent relationship. The current study examined the potential moderating role of positive parenting at Wave 1 on relations between perceived parental messages supporting fighting at Wave 1 and adolescent aggression based on parent- and student-report at Wave 2. Participants included a sample of 537 adolescents and their primary caregivers, recruited from four sites in the U.S. No significant moderating effects were found. However, parental messages supporting fighting were positively associated with increased student-reported aggression six months later, and positive parenting was related to decreased parent-reported aggression over the same timeframe. Implications suggest that parental messages supporting fighting and positive parenting represent a risk and promotive factor, respectively, in relation to aggressive behavior in early adolescence.
238

Leadership development, identity, culture and context : a qualitative case study

Nedjati-Gilani, Parisa January 2014 (has links)
This thesis explores the impact and effects of a leadership development programme in-depth and over time. There has been a lack of attention given to understanding the impact of such interventions in the academic literature. Where studies do investigate the impact (s) of leadership development they tend to focus almost exclusively on positive outcomes or the achievement of pre-determined targets and tend to be short-term in focus. This research finds that there is also a shadow side of leadership development, defined as the unintended effects of leadership development programmes which can be counter-productive and dysfunctional. A longitudinal case study approach was adopted comprising documentary analysis, observation and interviews, the latter of which were conducted with multiple stakeholders at three different junctures in time during and beyond the length of the leadership development programme. Three conceptual dimensions of identity, organisational culture and organisational context were identified which together facilitated a multi-faceted understanding of the changing impact and effects of the leadership development programme over time. In conclusion this thesis makes both a theoretical and methodological contribution by adding a longitudinal, multi-level analysis and evaluation of leadership development, evidencing both positive and shadow impacts and effects.
239

Vliv plavecké části triatlonu na celkový výkon v triatlonu v závodech mistrovství světa v letech 2000 - 2010 / Effect of swimming on the overall triathlon performance in triathlon races World Championships in years 2000 - 2010

Koktová, Veronika January 2011 (has links)
Title: The influence of swimming part of triathlon the total performance in competitions of world championships 2000-2010. Objectives: The aim is to investigate the influence of the swimming part of the total performance in triathlon in the lost 10 years. Methods: The relation between two variables (times from swimming and the total time of competitions from competitions of world championships 2000-2010 were described with the help of linear regression. Individual years were then compared in a point graph. Results: Our hypothese were confirmmed. It means that the result from the swimming part explains the result from the competition in less than 30%, which means the R2 is smaller than 0,3. We also found, that the influnence of the swimming part on the final result in triathlon has not changed in the last years. The relationship times in the swimming part and total (final) times was closest in 2005 (R2= 0,21). In other years, this dependence is lower, R2 was smaller than 0,07. Keywords: linear regression, longitudinal analysis, performance
240

Hull Shape Optimization for Wave Resistance Using Panel Method

Karri, Krishna M. 14 May 2010 (has links)
A ship must be designed for efficiency and economy, thus there is an everlasting desire for the design of better and better ships. One of the important factors which directly influence the worthiness of a design is its resistance. Throughout decades of ship design, the resistance is given top most importance as a design objective. With the increase in computational speeds of both software and hardware, there has been an opportunity for optimizing ship hulls using iterative methods of design and modification. A method for calculating resistance for a given hull geometry and to optimize it using optimization algorithms are required for achieving better hulls. The resistance is calculated using a panel method for a given hull and the hull geometry is later changed by applying Lackenby's method of longitudinal shift of stations. An optimization algorithm extracts the best possible design out of the numerous design alternatives possible.

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