Physical activity (PA) has been labelled the miracle drug (Pimlott, 2010) and participating in regular PA has ample physical and mental wellbeing benefits. However, physical inactivity remains a critical public health concern, particularly across adolescence. In England the proportion of adolescents aged 13-15 years meeting the recommended guidelines for PA decreased significantly from those at a younger age (Health and Social Care Information Centre, 2009; 2012; 2015). The adolescent years (13 18 years) have been identified as the age of greatest decline in PA, although it is possible that large declines can also be seen at younger ages (Sallis, 2000). Among girls the decline in PA is greater at younger ages (9 12 years old) and among boys it is greater at older ages (13 16 years old) (Dumith, Gigante, Domingues, & Kohl, 2011). Thus, examining behaviour of early adolescents (aged 11-13 years) is a primary focus of this thesis. Researchers have called for a more comprehensive grasp of PA correlates and determinants and their impact on behaviour (Biddle & Mutrie, 2001, 2008). This broader picture needs to incorporate longitudinal study designs to accurately portray developmental changes (Evenson & Mota, 2011). This thesis aims to work towards a better understanding of associations among variables across aspects of the ecological model in relation to PA behaviour during early adolescence. Early adolescents within their first year of secondary school (year 7, aged 11 12 years) were recruited through schools across the East Midlands, United Kingdom (UK). These participants completed various measures across an 18 month period to compile all data required for the thesis. The thesis begins with a focus on active transport as a means of commuting to school which can significantly contribute to overall PA levels (Aibar, Bois, Generelo, Bengoechea, & Paillard, 2015; Slingerland, Borghouts, & Hesselink, 2012). The distance from home to school is an important influence on the decision to use active transport; however, ecological perspectives would suggest this variable may interact with individual, interpersonal and environmental factors. Therefore, the first study of this thesis investigates whether the relationship between distance to school and active transport is moderated by (i) gender, (ii) biological maturation, (iii) perceived family support for PA and (iv) multiple deprivation. Cross-sectional results from the baseline data collected demonstrated that the relationship between distance to school and the likelihood to actively travel to school is moderated by biological maturation, multiple deprivation and family support of PA in adolescents. Further analysis revealed that late-maturing children, those from less socio-economically deprived backgrounds and children with low family support of PA are less likely to actively commute to school as distance to school increases. Due to the interaction between these variables described above, the second study focused on the variables collectively using a person-oriented approach, which aimed to classify distinct profiles of early adolescents based on correlates of PA. The outcome variables were also broadened to include active transport and overall PA across two time points. Findings from this second study illustrate that the highly supported, shortest commuters produced the highest levels of self-reported PA and that affluent, short commuters were the most likely to use active transport to travel to school. The affluent, short commuters lived a relatively short distance to school in areas of the lowest deprivation and had relative moderate family support of PA. The highly supported, shortest commuters were characterised by the highest family support of PA and lived the shortest distance to school in areas of low deprivation. Study 1 evidenced an association between biological maturation and PA behaviour; however, study 2 displayed that biological maturation did not meaningfully contribute to the class characteristics, and were not a predictor of PA. Previous evidence as to whether early, average or late maturing adolescents are more likely to disengage from PA is mixed and tends to focus on one gender only (Sherar, Cumming, Eisenmann, Baxter-Jones, & Malina 2010; Bacil, Mazzardo, Rech, Legnani, & Campos, 2015). Thus for the third study a more focused inspection of biological maturity was undertaken. Biological maturity status was investigated as a predictor of PA behaviour at two subsequent time points (6 9 months after baseline and 12 18 months after baseline) and whether there was variation across genders. Findings displayed that biological maturity status does not predict subsequent PA, with no distinction across genders. To conclude, the final study examined additional forms of PA behaviour. For children to develop and maintain healthy PA behaviours, their PA during the school day, particularly during physical education (P.E) classes is important (Owen, Smith, Lubans, Ng, & Lonsdale, 2014). Self-reported PA was divided into school-time PA (during P.E. lessons, break and lunchtimes) and leisure-time PA (after school, during evenings and weekends). The final study fully utilised the longitudinal data collected and utilised longitudinal growth modelling to describe the changes in PA behaviour across 12-18 months during early adolescence. Results displayed that school-time PA and leisure-time PA are distinct. Males; those from less deprived backgrounds and individuals with higher family support of PA all separately reported more school-time PA than their counterparts (females, those from higher deprived backgrounds and individuals with lower family support of PA) at baseline. Males and those with higher family support of PA also reported more leisure-time PA than their respective counterparts at baseline. On average, both genders decreased in school-time PA across 18 months yet for leisure-time PA, on average, there was no change over time and no significant difference in the rate of change between genders. There were no observed significant differences in the rate of change between multiple deprivation status and biological maturation across the 18 months for both behaviours. For family support, on average school-time PA decreased over time and results showed significant difference in the rate of change between individuals with lower or higher levels of family support of PA across the 18 months. On average, there was no change over time for leisure-time PA yet there was a significant difference in the rate of change between individuals and their family support of PA across 18 months. Further analysis demonstrated if an individual s family support increases, so does their leisure-time PA and vice versa. These overall key findings demonstrate the complexity of PA behaviour throughout early adolescence. This thesis works towards predicting individuals, correlates and determinants that may be susceptible to physical inactivity and/or a decrease in activity over time. Results can be used to target and direct PA intervention work.

Previous research on marital help-seeking has often focused on formal approaches such as marital therapy or relationship education and there is a greater need to understand married individual's informal help-seeking behaviors. This study explores both formal and informal help-seeking behavior using a national sample of 745 participants who have thought about divorce within the past 6-months. Findings indicate these participants more often engaged in informal help-seeking approaches to repair their marriage. Of those sampled, only 25% engaged in marital therapy together and only 9% engaged in a marriage strengthening class while over 30% read a relationship themed self-help book or visited a website as a form of repair-behavior. A series of logistic regressions indicate there are no statistically significant differences in help-seeking behavior by gender while those that were highly religious and had more serious thoughts of divorce were more likely to engage in all forms of help-seeking. A latent class analysis was conducted to determine if there are common patterns in help-seeking behavior. Results indicate there are 4 distinct types of help-seekers: Highly Engaged (5%), Private Information Gatherers (7%), Private Seekers (43%), and Minimally Engaged (45%). Follow up analyses indicate having higher levels of religiosity or having more serious thoughts of divorce were both associated with a greater likelihood of being in one of the three more engaged classes compared to the minimally engaged class. Results demonstrate the need to place more emphasis on informal help-seeking approaches, private repair-behaviors, and to consider common patterns in help-seeking behavior.

Latent Class Analysis was used to explore different subgroups of individuals based on identity processes (using the DIDS) and protestant fundamentalism. Results indicate that a 6-group solution provided the best fit for our data. The six groups differed in terms of identity process variables (especially exploration in breath, exploration in depth, and identification with commitment), but only modestly in terms of fundamentalism.

The purpose of this dissertation was to expand the understanding of youth in psychiatric residential treatment facilities by using psychosocial indicators to develop subgroup profiles. Additionally, differences in treatment outcomes between subgroups and the extent to which within-treatment factors accounted for observed differences in treatment outcomes between subgroups were examined. Data were extracted from the case records of 447 youth who were served in psychiatric residential treatment facilities over a seven year span of time. A latent class analysis was used to identify and describe subgroups. A series of multivariate regression analyses were used to examine group differences in functional impairment at discharge. Next, a path analysis was used to determine if there were differences in average change in functional impairment from admission to discharge between subgroups and to test within treatment factors as potential mediators of group differences. Finally, a logistic regression was used to determine if there were differences between groups in the probability of discharging to a community-based placement or discharging to another congregate care facility. The latent class analysis revealed four distinct subgroups of youth. The analyses of treatment outcomes revealed statistically significant differences in the level of functional impairment at discharge and average change in impairment between groups. Results from the path model of indirect effects supported that within treatment factors accounted for a statistically significant proportion of the observed difference in change between groups. No differences were found in discharge placement outcomes between groups. Implications for future research, practice and policies focused on youth in residential treatment are discussed.

潛在群體分析及對應分析是在探討多個類別變數間關係常用的兩種分析方法，因其運用之領域不同，解說之方式不一，以致過去常被認為是兩種不相關的分析方法，然而實際卻非如此。本研究之目的係就雙變數及多變數的情況，針對這兩種分析方法間之關係作詳細的探討，並說明其對等及不對等的時機。 / Latent class analysis and correspondence analysis are two well-known methods that can be used to study the relationship between categorical variables. Since the two were developed and applied in two different fields in the past, they were never thought to be related. In this study, we examine the relationship between the two in more details. We further point out the situations where they are equivalent, and where they are not.

Over the past decades financial investment of non-financial businesses has been rising and accumulation of capital goods has been declining. The first part of the paper offers a novel theory to explain this phenomenon. Financialization, the shareholder revolution and the development of a market for corporate control have shifted power to shareholders and thus changed management priorities, leading to a reduction in the desired growth rate. In the second part the link between accumulation and financialization is tested econometrically by means of a time series analysis of aggregate business investment for USA, UK, France, and Germany. Extensive test of robustness are performed. For the first three countries evidence that confirms the negative effect of financialization on accumulation is found. (author's abstract) / Series: Working Papers Series "Growth and Employment in Europe: Sustainability and Competitiveness"

<p>This study examines whether trajectories of multiple social role occupancy, measured by level and dynamics of spouse, parent, and worker roles, are associated with mortality and concurrent trajectories of depressive symptoms and self-rated health. I frame hypotheses with role strain, role enhancement, role context, stress process, and life course theories to examine both within-person changes over age and between-person predictors of health status.</p><p></p><p>I use data from the Americans' Changing Lives Study, a nationally representative accelerated cohort panel study of U.S. adults interviewed in 1986, 1989, 1994, and 2001/2 with mortality tracking through 2006. I use latent class analysis to estimate disaggregated trajectories of role occupancy, role strain, role satisfaction, depressive symptoms, and self-rated health across the adult life course. I then use multinomial and logistic regression analyses to examine associations between role trajectories and health outcomes.</p><p>I find that (1) there is significant heterogeneity in trajectories of role occupancy and characteristics across the adult life course; (2) higher levels of social role occupancy are associated with better depressive symptom and mortality outcomes; (3) lower levels of role strain and higher levels of role satisfaction are associated with better depressive symptom outcomes, and (4); the association between role occupancy and health is robust to the inclusion of role characteristics. Thus, I find support for the role enhancement hypothesis in that higher levels of role occupancy are associated with better health outcomes irrespective of reward and strain associated with those roles.</p> / Dissertation

The conceptualization of intimacy within adolescent romantic relationships has typically taken a linear approach: Adolescents experience initial romantic encounters within a group context and progress towards an exclusive dyadic dating relationship. This study uses a person-centered approach and conceptualizes adolescent romance as multi-dimensional.In Study 1, a large, nationally representative dataset (the National Longitudinal Study of Adolescent Health) was used to classify 10th and 11th grade adolescents into ideal romantic relationship styles via Latent Class Analysis. Four classed emerged: Concealers (3.6%; n=276), Abstainers (32.6%; n=2508), Engagers (51.4% of the sample; n= 3955), and Family Builders (12.5%; n=959). Concealers, primarily non-White ethnicities, preferred low social/emotional involvement but moderate sexual activities. Most adolescents with same-sex attractions were concealers. Concealers reported the greatest miss-match between ideal and real relationship activities. Abstainers, predominantly females, preferred: high social/emotional activities, to talk less about contraception/STDs, and low sexual activities. Engagers, predominantly male and White, scored highest on all social, emotional, and physical activities (exception of 'seeing less of friends', 'sex', 'pregnancy', and 'marriage'). Family builders, overly-represented by Latino, preferred high social, emotional, and physical dimensions including seeing less of friends, sexual intercourse, pregnancy, and marriage. Moderate discrepancies occurred between ideal and real activities.Study 2 was a focus group study of White and Latino adolescents (N=75) entering 10th through 12th grades. Using a symbolic interactionism theoretical framework, adolescents described four types of sexual relationships within their social subjective realities: Going-out, dating, friends with benefits, and hooking up. Going-out relationships, an exclusive and emotionally/physically close relationship, were the most easily described and the most intense and committed relationships. Dating relationships, however, were the most common type of sexual relationship and were less easily defined, partially due to the ambiguity of the relationship itself which is to 'get to know each other'. These relationships were somewhat exclusive and required less obligations. Friends with benefits (primarily physical relationships) and hooking up (single physical encounters) were casual relationships that required little to no commitment.Findings are interpreted via a developmental/feminist lens. Gender inequality and sexual double standards are potent forces that continue to shape adolescent's sexual behaviors, feelings, and experiences.

This thesis is an investigation of external biosecurity and its application to risk-based surveillance approaches in the southern Ontario swine industry. In each of two datasets, the best number of groups to describe biosecurity practices was identified, resulting in two groups with high biosecurity standards and one group with low biosecurity standards. Multinomial logistic regression models identified herd density, herd size, and herd type among significant predictors of biosecurity group membership. A map of southern Ontario that can be used as a tool in the risk-based surveillance of contagious swine diseases was developed using geographic information about swine density, and the distribution of herds belonging to the high biosecurity groups. Finally, multiple correspondence analysis examined how individual biosecurity practices form strategies on sow farms. Some practices that are generally considered high-risk were closely associated with other practices that mitigate the risk, suggesting that evaluation of the overall strategy is essential for complete assessment of biosecurity. / The Ontario Ministry of Agriculture, Food and Rural Affairs (under the Emergency Management research theme); Ontario Pork; the Ontario Pork Industry Council's Swine Health Advisory Board; the Natural Sciences and Engineering Research Council of Canada;

This thesis was to determine the prevalence and distribution of paratuberculosis in the Ontario dairy sheep and dairy goat industries, identify potential risk factors for herds which tested positive, evaluate the accuracy of seven commercially available individual and two bulk tank diagnostic tests in these two populations, and determine the circulating strains of Mycobacterium avium ssp. paratuberculosis in faecal isolates obtained. A cross-sectional study was conducted between October 2010 and August 2011 in 29 goat herds and 21 sheep flocks located in Ontario. On each farm, 20 lactating animals over the age of two years were randomly selected and faeces, blood, and milk were sampled from each animal, and a bulk milk sample from each herd. A questionnaire inquiring about herd management and biosecurity behaviours was also completed. The seven individual animal tests evaluated were: faecal culture using the BACTEC® MGIT™ 960 liquid culture system, direct faecal PCR (Tetracore®, Rockville, MD) based on the hspX gene, the Prionics® ELISA on serum and milk, the IDEXX® ELISA on serum and milk, and the agar gel immunodiffusion (AGID) test on serum. The test evaluations used both frequentist (faecal culture - reference test) and Latent Class Analysis/Bayesian (LCA/BM) methods (no reference test). In goat herds, faecal culture demonstrated the highest sensitivity (Se), 81.1% (LCA/BM). In sheep, while faecal culture demonstrated the highest Se, 49.5%, there was a small probability it was higher than faecal PCR Se at 42.4%. The bulk tank tests evaluated were the 'Hyper-ELISA' test and real-time PCR test based on IS900 (AntelBio®). While PCR did not demonstrate sufficiently high Se to be used as a herd-level test, the Hyper-ELISA performed well as a herd-level test identifying farms with high prevalence when the cut-off was reduced to 0.05. Overall herd-level apparent prevalence was 79.3% in goat herds and 57.1% in sheep flocks when faecal culture was the reference standard and true herd-level prevalence (LCA/BM) was 83.0% and 66.8% in each population respectively. This high prevalence reveals a need for the implementation of a small ruminant paratuberculosis control program in Ontario, Canada based on testing, improving youngstock management, and strengthening biosecurity practices. / AHSI, OMAF