Rumination has been consistently found to be a risk factor of depression. However, few studies examined rumination and its relationship with depression, and the protective role of such individual positive traits as hope, in a Hong Kong Chinese context. As opposed to western findings, a recent local study found that the two components of rumination (Treynor, Gonzalez, & Nolen-Hoeksema, 2003), namely brooding and reflective pondering, were not correlated, and the latter was rather adaptive in predicting depressive symptoms (Lo, Ho, & Hollen, 2008). Together with some psychometric issues revealed in the same study, it is unclear if the two-factor model of rumination is applicable in the Hong Kong Chinese context. In addition, given that hope only buffers against negative impact of risk factors of depression, whether the moderating effect of hope on the relationship of brooding and reflective pondering with depressive symptoms in Geiger and Kwon’s (2010) western sample can be replicated in Hong Kong Chinese populations is not clear. Therefore, the present study re-examines the two-factor model of rumination and its relationship with depressive symptoms, and the moderating role of hope in a Hong Kong Chinese sample using a longitudinal design. Adult Trait Hope Scale, Ruminative Response Scale, and Center for Epidemiologic Studies Depression Scale were administered to 189 Hong Kong Chinese university students at lectures with a four-week interval between the two time-points. Analyses using hierarchical linear regression were conducted to examine the relationship of brooding and reflective pondering, and their relationship with depressive symptoms and the role of hope, both concurrently and prospectively. Results confirmed the applicability of the two-factor model of rumination in the Hong Kong Chinese college sample. Rumination (total) and brooding consistently predicted depressive symptoms. Also, moderating effect of hope on the relationship of brooding and depressive symptoms was replicated using the time 1 data in the present study. Nonetheless, contrary to the recent local finding by Lo et al. (2008), brooding and reflective pondering were positively correlated as in western samples, and there was some evidence of one-way relationship from reflective pondering to brooding as shown by the longitudinal data. Reflective pondering itself was neither adaptive nor maladaptive, because there was no significant relationship between reflective pondering and depressive symptoms after controlling for level of brooding. Hence, hope had no interaction with reflective pondering in predicting depressive symptoms. For longitudinal data, after controlling for baseline level of the dependent variables, the one-way relationship from reflective pondering to brooding, the relationship of rumination (total) and brooding with depressive symptoms, and the moderating effect of hope on the relationship between brooding and depressive symptoms, all became nonsignificant. The findings of the present study support the use of the two-factor model of rumination in Hong Kong Chinese context, and suggest that the two components of rumination were correlated probably because reflective pondering tended to lead to brooding. This study also offers further empirical support for brooding being a more robust risk factor of depression than reflective pondering and the buffering impact of hope on psychological well-being. Implications of the results, limitations of this study and recommendations for further research were also addressed. / published_or_final_version / Psychology / Master / Master of Philosophy

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<p>Research into how different life events shape individual religiosity has a long history within sociology. However, some scholars have begun to question whether research in this area has methodologically justified making strong causal claims. In an effort to re-center religion within the field of sociological concerns, quantitative sociologists of religion have tended to over-state the meaning of their statistical relationships and this has led to many of their causal assumptions being unstated and/or untested in their analyses. The advances in causal statistical modeling and counterfactually grounded analyses has led to the development of statistical models that are better able to establish causal relationships. It is time to begin implementing these approaches within the sociology of religion. This more rigorous statistical approach runs the risk of demonstrating that social life’s influence on religion may be less impressive than was previously thought. But researchers in this area must take this risk to develop a better sense of the real effects of society on religion. This in turn will provide a better foundation for developing theories of religion’s role in our modern world. </p><p> One way in which sociologists of religion can improve their causal modeling strategies is through the use of longitudinal data and methods. In recent years there has been a significant increase in the availability of large-scale longitudinal data that collects information on respondents’ religious belief, practice, and belonging. With these data, scholars interested in religious change can move away from their reliance on comparing individuals to one another – a constraint of cross-sectional data – and begin to analyze how certain life course events may lead to change in individual religiosity. I revisit two important areas within the sociology of religion –the relationship between family formation and religious service attendance and the effects of educational achievement on religious beliefs and practices – to assess whether these relationships can be considered causal in light of results from longitudinal statistical models. By implementing longitudinal models, I am able to directly assess whether between-individual differences or individual change over time is driving the statistical relationships found in my analyses. I will show that the story we thought we knew about how religion responds to family formation and educational attainment changes when these additional statistical tests are brought to bear on the data.</p> / Dissertation

This thesis aimed to evaluate the feasibility and utility of a sickle cell disease registry for clinical patient management and research. Five hospitals out of nine in the North West London health region participated in the registry, with 78 percent coverage of the sickle cell disease population. There was 80% case ascertainment in participating hospitals. Aggregated anonymised demographic and diagnostic data was collected for all haemoglobinopathy patients. This provided the core dataset for quantifying prevalence of sickle cell and thalassaemia and mapping local hospital workloads and service requirements. Thirteen percent of HbSS adult patients were taking hydroxycarbamide. The cohort of patients treated with hydroxycarbamide was evaluated. Sixty two of the 80 patients started on treatment were included. Follow-up was censored after 9 years, totalling 249 person-years of data with a median follow-up of three years (IQR, 1-6). Results showed that haematological benefits were maintained in the long-term with treatment, but evidence of long-term clinical effectiveness was less strong. This appeared to be due to the patterns of clinical management in everyday practice. Patients tend to be treated with modest doses of hydroxycarbamide due to intolerance or inability to attain or maintain maximum tolerated dose. For example maximum tolerated dose was the aim of treatment for 91% of patients but it was achieved for 65% of participants. Non- compliance with treatment and monitoring schedule was the main reason for non- attainment. Results suggest that it is sensible to strive for maximum tolerated dose to ensure therapy remains effective, but with more realistic expectations of the dose patients can attain and maintain. Doses in adult patients average 20mg/kg/day and 25mg/kg/day in children. Adult patients may be able to achieve a higher dose, if there was more stringent monitoring and improved management of non-compliance. The North West London HU Sub-Registry proved useful for measuring long-term effectiveness and tolerability of hydroxycarbamide. Routinely collected data was utilized for both clinical management and research purposes. The novelty lay in examination of the nuances of routine clinical practice. An electronic patient record was developed as a clinical management tool. It is the first study reporting long-term outcomes for UK sickle cell disease patients on hydroxycarbamide. Findings should help clinicians devise effective treatment protocols and strategies for managing patients commenced on this therapy. Interventions need to be targeted at increasing utilisation, patient adherence and persistence with treatment. The electronic patient record could be used to maximise treatment benefit and improve adherence. More effective involvement of the multidisciplinary team and primary care colleagues in patient education and management should improve usage. Patients and carers need up to date and easy to assimilate information to make informed decisions about treatment options. Maintaining a SCD registry is challenging. Models which operate as clinical information systems provide an incentive for participation. These enable active involvement of local care providers in registry management and the ability to keep and utilize their own data. Clinicians require accurate and current data for patient management and to enable them to benchmark their local outcomes against national outcomes and care standards.

The main objectives of this master thesis are to explore the effectiveness of nonlinear mixed effects model for longitudinal data. Mixed effect models allow to investigate the nature of relationship between the time-varying covariates and the response while also capturing the variations of subjects. I investigate the robustness of the longitudinal models by building up the complexity of the models starting from multiple linear models and ending up with additive nonlinear mixed models. I use a dataset where firms’ leverage are explained by four explanatory variables in addition to a grouping factor that is the firm factor. The models are compared using comparison statistics such as AIC, BIC and by a visual inspection of residuals. Likelihood ratio test has been used in some nested models only. The models are estimated by maximum likelihood and restricted maximum likelihood estimation. The most efficient model is the nonlinear mixed effects model which has lowest AIC and BIC. The multiple linear regression model failed to explain the relation and produced unrealistic statistics

A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / End‐of‐life (EOL) care and decision‐making in pediatrics is a challenging and complex aspect of patient care experienced by residents and physician attendings. Previous studies have evaluated determinants that contribute to physicians’ attitudes towards EOL care as well as preparedness of students and residents in EOL decision‐making. However, the determinants contributing to a physician’s ability to make such decisions and feel confident in addressing EOL issues are dynamic. Recognizing that decision‐making changes over time, identifying when these changes occur may demonstrate the need for educational interventions for medical students and residents early in their career to help prepare them for EOL decision‐making. A longitudinal assessment of changes in attitudes and knowledge of EOL discussions and how they impact EOL decision‐making was not previously evaluated. This preliminary study establishes a baseline for medical student, resident, and attendings for EOL decision‐making and those factors that contribute to their decisions. This preliminary data has demonstrated a difference amongst attendings compared to residents and students. Despite low probability of survival, residents and students are more likely to select more aggressive management options when compared to attendings. Data obtained after completion of future surveys will show when decision‐making changes, which factors contribute to these changes and their significance in making decisions, and when participants are comfortable addressing EOL care.

Introduction. The relationships among military service, combat intensity and long-term health effects were investigated in a cohort of 6,355 Vietnam-era American Legionnaires who were recruited in 1984 and followed through 1998. First, the effect of Vietnam service on coronary heart disease (CHD) risk was assessed among 3,781 veterans who responded to both questionnaires. Next, the effect of serving in Vietnam and combat exposure was investigated as risk factors for the mortality of the cohort. Finally, potential threats to the validity of this study were evaluated.Methods. Military service and lifestyle factors were assessed by questionnaires in 1984 and 1998. Vital status in 1998 was determined and causes of death were ascertained through the National Death Index. Cox proportional hazards modeling was used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for CHD incidence and mortality in relation to service location and combat exposure, adjusting for age, smoking, alcohol consumption, body mass, and hypertension. Response bias and reliability of self-reported data were examined.Results. Serving in Vietnam was associated with an increased hazard of developing heart disease (HR=1.37, 95% CI: 1.09, 1.73), after controlling for independent risk factors. Vietnam veterans experienced a 50% higher mortality than non-Vietnam veterans during 14-year follow-up (HR=1.48, 95% CI= 1.13 - 1.93), which increased with combat intensity after adjustment for other risk factors, (low combat: HR 1.17, 95% CI 0.79 - 1.73; medium combat HR=1.51, 95% CI 1.05 - 2.17; high combat HR=1.82, 95% CI 1.20 - 2.76). A stronger relationship was observed by level of combat for CHD mortality (low combat: HR =1.48, 95% CI 0.75 - 2.95; medium combat HR= 2.01, 95% CI 1.06 - 3.79; high combat HR= 2.27, 95% CI 1.08 - 4.79). Results showed that non-respondents differed only slightly from respondents for important variables potentially related to exposures and chronic disease outcomes. Furthermore, veteran self-report was moderately to highly reliable when measured over a 14 year period.Conclusions. Vietnam veterans are still experiencing higher rates of adverse health effects, even more than thirty years after their military service. These data support a long term and independent adverse effect of military service in Vietnam on cardiovascular health.

Eucalypt trees are one of tree species used for the manufacturing of papers in South Africa. The manufacturing of paper consists of cooking the wood with chemicals until obtaining a pulp. The wood is made of different cells. The shape and structure of these cells, called wood anatomical characteristics are important for the quality of paper. In addition, the anatomical characteristics of wood are influenced by environmental factors like climatic factors, soil compositions etc…. In this study we investigated the effects of the climatic factors (temperature, rainfall, solar radiation, relative humidity, and wind speed) on wood anatomical characteristics of two Eucalyptus clones, a GC (Eucalyptus grandis × camuldulensis) and a GU (Eucalyptus grandis × urophylla). Nine trees per clone have been selected. Two sets of data have been collected for this study. The first set of data was eleven anatomical characteristics of the wood formed daily over a period of five years. The second set of data was the daily measurement of temperature, rainfall, solar radiation, relative humidity and wind speed in the experimental area. Wood is made of two kinds of cell, the fibres and the vessels. The fibres are used for the strength and support of the tree and the vessels for the nutrition. Eleven characteristics related to those cells have been measured (diameter, wall thickness, frequency). These characteristics are highly correlated. To reduce the number of response variables, the principal component analysis was used and the first four principal components accounts for about 95% of the total variation. Based on the weights associated with each component the first four principal components were labelled as vessel dimension (VD), fibre dimension (FD), fibre wall (FW) and vessel frequency (VF). The longitudinal linear mixed model with age, season, temperature, rainfall, solar radiation, relative humidity and wind speed as the fixed effects factors and tree as random effect factor was fitted to the data. From time series modelling result, lagged order of climatic variables were identified and these lagged climatic variables were included in the model. To account for the physical characteristic of the trees we included the effect of diameter at breast height, stem radius, daily radial increment, and the suppression or dominance of the tree in the model. It was found that wood anatomical characteristics of the two clones were more affected by climatic variables when the tree was on juvenile stage as compared to mature stage. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

Studies over the past couple of decades have depicted loneliness as a significant concern to physical health, although its meaning for overall health outcomes is still unclear. The precise impact of loneliness on life expectancy and on specific disease processes remains unknown. With regression modeling techniques, this thesis uses data from the Alameda County Health and Ways of Living Study to characterize the impact of loneliness on self-rated health, mortality, and fatalities from specific diseases. A key hypothesis is that loneliness as a health problem hinges on its persistence over time. This hypothesis is also tested by examining the reliability of the loneliness measure across the full 34 years of the survey. A second test is to examine its interplay with marital status as a mutable social circumstance. Results show that loneliness is a risk factor for poor self-rated health, non-ischemic cardiovascular diseases, cerebrovascular diseases, infections, and overall mortality. Results also show that loneliness need not be a stable problem across the life span in order to pose health risks. The reliability of the loneliness measure fades across time and levels of loneliness also vary with changes in marital status. Loneliness did not clearly mediate the impact of marital status on self-rated health, mortality, or specific causes of death.

This dissertation investigates the effects and value of instructional activities for improving second language use of English articles. After reviewing a number of issues concerning pedagogical, linguistic, psycholinguistic, and internal validity, this study presents the results of eight longitudinal time-series case studies of adult Japanese learners of English residing in Vancouver, Canada, four of whom received grammatical explanations, input processing activities, and output practice activities regarding English article use. Learner development was assessed on three different narrative retelling tasks (spoken, written, and cloze) and the production was analysed with reference to specific contexts of use, indicating the form-function mappings that comprised the learners' interlanguage knowledge. The results indicated that the learners' interlanguage production exhibited (a) the anticipated task variation, with greater suppliance of the on tasks that allowed greater attention to form, and (b) the anticipated discoursal variation, with the supplied more consistently when it was primed as a redundant element on the written task and with the supplied less consistently when it was efficiently deleted as a redundant element on the spoken task. The results also indicated the variable nature of individual development and the value of assessing development longitudinally on different tasks. Importantly, the results indicated that the learners improved or continued improving after instruction, and strongly suggested that instruction can cause automatization of interlanguage knowledge. This finding suggests that form-focused instruction may be valuable for second language learning, and that pedagogical positions opposing form-focused instruction may need to be revised or abandoned.