No description available.

Thesis (doctoral)--Friedrich-Alexander-Universität zu Erlangen.

Thesis--Helsinki. / Includes bibliographical references (p. 44-53).

This research models the behavior of a multi-task system with respect to time. The type of multi-task system considered here is one in which not all system components are required to perform each task. Each component may, however, be used for more than one task. Also, it is possible that some of the components may be required for every task that the system performs. The components that are required for a subset of the tasks are considered to be intermittently demanded components and those components required for every task are continuously demanded components. This modeling approach assumes that the system is subject to a Modified Age Replacement Policy (MARP). With a MARP the intermittently demanded components are maintained during their idle periods and the continuously demanded components are replaced according to their age replacement times. A renewal theory approach is used to develop an availability expression for the multi-task system. Past research has focused on systems consisting of continuously demanded components and typically does not distinguish between elapsed clock time and elapsed operating time in the renewal density function expressions. This research recognizes that the operational age of an intermittently demanded component is different than the chronological age of the component. The renewal density function and availability measures are modeled using joint density functions defined on both clock time and operating time. The expressions are evaluated numerically using a multidimensional numerical integration routine. The results show logical behavior of the joint density functions used to define the availability measure. The availability measure also displays behavior consistent with the definition of a multi-task system. This model is an important development in the need for stochastic models of highly complex systems. The model is also a first step in defining performance measures for systems composed of both intermittently demanded components and continuously demanded components. / Ph. D.

Background: There is accumulating evidence that greater availability of neighbourhood green space is associated with better health. One mechanism proposed for this association is that green space provides a venue for, and therefore encourages, physical activity. It has also been suggested that socio-economic health inequalities may be narrower in greener areas because of the equalised opportunity for physical activity green spaces provide. However, research, exploring associations between availability of green space and physical activity has produced mixed results. Failure to account for the type and amount of physical activity which occurs specifically in green space may account for these mixed findings. This thesis therefore explored the extent to which green space is a venue for physical activity and whether this could account for better health and narrower socio-economic health inequalities in greener areas. Methods: Secondary analyses were conducted on two cross-sectional surveys of adults (16+) living in urban areas across Scotland. The first survey included individual level health, total physical activity, physical activity specifically in green space and socio-demographic characteristics. These data were matched to an objective measure of neighbourhood green space availability. The second included self-reported data on green space availability, quality, green space use, health and socio-demographic characteristics. Objective and perceived measures of green space were assessed in relation to (a) health, (b) use of green space and (c) physical activity in green space using logistic regression models. Interactions between socio-economic position and each outcome were assessed. Results: The objective availability of green space in a neighbourhood was not associated with health, total physical activity or that specifically in green space. The perceived availability and quality of green space was positively associated with more frequent use, but only perceived quality was associated with better population health. There was no evidence that socio-economic inequalities in health, use of green space or physical activity within green space were narrower in greener areas of Scotland. Conclusion: There was no evidence that physical activity specifically in green space was associated with better health or narrower socio-economic health inequalities. Further research exploring green space characteristics over and above availability, may help determine whether green space is salutogenic in Scotland.

No description available.

The hepatitis C virus (HCV) is highly prevalent among people who inject drugs (PWID) in Scotland and the large majority of new HCV infections occurring in Scotland are within this population group. Harm reduction interventions, mainly sterile injecting equipment provision (IEP) and opioid substitution treatment (OST), to prevent the transmission of blood-borne viruses among PWID, were implemented in Scotland in the late 1980s/early 1990s. More recently, government policy initiatives, particularly the Hepatitis C Action Plan for Scotland, have stipulated the scale-up of these interventions. The overarching aim of this thesis was to investigate the impact of harm reduction interventions on the transmission of HCV among PWID in Scotland. Five secondary objectives were addressed in order to fulfil the main aim: (i) to review the international literature on the effectiveness of IEP and OST in preventing HCV transmission; (ii) to determine the association between self-reported sharing of needles/syringes and incident/prevalent HCV infection; (iii) to determine the association between sharing non-needle/syringe injecting paraphernalia and incident HCV infection; (iv) to determine the incidence of HCV among PWID in Scotland; and (v) to determine the association between self-reported uptake of IEP/OST and incident HCV infection. To address the first thesis objective, a systematic review of the literature was undertaken to identify existing international research evidence (published up to March 2007) for the effectiveness of harm reduction interventions. While HCV was the main outcome of interest, HIV and injecting risk behaviour (IRB) were also considered. A review of reviews approach identified: insufficient evidence that sterile needle and syringe provision (NSP) was effective in preventing HCV transmission; tentative evidence that NSP was effective in preventing HIV transmission; sufficient evidence to support the effectiveness of NSP in reducing self-reported IRB; and little to no evidence on needle/syringe vending machines, outreach NSP or the provision of other injecting paraphernalia (spoons, filters, water) in relation to any of the outcomes. With regard to OST, the findings were: insufficient evidence to show that OST has an impact on HCV transmission; sufficient evidence to support the effectiveness of continuous OST in reducing HIV transmission; and sufficient evidence to support the effectiveness of OST in reducing IRB by reducing the frequency of injection, the sharing of injecting equipment and injecting risk scores. An update to the review of reviews was undertaken to include literature published through March 2011, and found that little changed as a result of additional published reviews: in the main, the evidence statement for the effectiveness of OST with regard to HCV was upgraded from insufficient to tentative. The finding of weaker evidence with regard to biological outcomes (e.g. HCV, HIV), as compared with behavioural outcomes, indicated that low levels of IRB may be insufficient to reduce high levels of transmission, particularly for HCV. The subsequent chapter aimed to address the second thesis objective, by summarising, and exploring factors that explained the variation in, the measure of association between self-reported sharing of needles/syringes and HCV prevalence/incidence among PWID. A systematic review and meta-analysis were undertaken to identify and combine the results of European studies of HCV prevalence (or incidence) among those who reported ever/never (or recent/non-recent) sharing of needles/syringes. Among the 16 cross-sectional studies and four longitudinal studies identified, the pooled prevalence of HCV was 59% among PWID who reported never sharing needles/syringes and the pooled incidence of HCV was 11% among PWID who reported not recently sharing needles/syringes. Random effects meta-analysis generated a pooled odds ratio (OR) of 3.3 (95% confidence interval [CI] 2.4-4.6), comparing HCV infection among those who ever (or recently) shared needles/syringes relative to those who reported never (or not recently) sharing. Differences in pooled ORs were found when studies were stratified by recruitment setting (prison vs. drug treatment sites), recruitment method (outreach vs. non-outreach), sample HCV prevalence and sample mean/median time since onset of injecting. High incidence/prevalence rates among those who did not report sharing needles/syringes during the risk period may be a result of a combination of unmeasured risk factors (such as sharing non-needle/syringe injecting paraphernalia) and reporting bias. Study design and population were found to be modifiers of the size and strength of association between HCV and needle/syringe-sharing. To address the third thesis objective, the risk of HCV associated with sharing injecting paraphernalia (spoons, filters and water) was investigated using data from the 2008-09 and 2010 sweeps in a series of national cross-sectional surveys of PWID in Scotland, collectively called the Needle Exchange Surveillance Initiative (NESI). Logistic regression was used to examine the association between recent HCV infection (anti-HCV negative and HCV-RNA positive individuals) and self-reported measures of injecting equipment sharing in the six months preceding interview. Twelve percent of the sample reported sharing needles/syringes and 40% reported sharing paraphernalia in the previous six months. The adjusted odds ratios (AORs) for sharing needles/syringes (with or without paraphernalia) and sharing only paraphernalia in the last six months were 6.7 (95% CI 2.6-17.1) and 3.0 (95% CI 1.2-7.5), respectively. Among those who reported not sharing needles/syringes, sharing spoons and sharing filters were significantly associated with recent HCV infection (AOR 3.1, 95% CI 1.3-7.8 and 3.1, 95% CI 1.3-7.5, respectively); sharing water was not. This cross-sectional approach to the analysis of the association between sharing paraphernalia and incident HCV infection demonstrated consistent results with previous longitudinal studies. The prevalence of paraphernalia-sharing in the study population was high, potentially representing a significant source of HCV transmission. Addressing the fourth and fifth thesis objectives, a method to determine the incidence of HCV among PWID using a cross-sectional design was applied, and the associations between self-reported uptake of harm reduction interventions (OST and IEP) and recent HCV infection were examined. This was undertaken on data from the first sweep (2008-09) of NESI. Twenty-four recent HCV infections (as defined above) were detected, yielding incidence rate estimates ranging from 10.8-21.9 per 100 person-years. After adjustment for confounders, those with high needle/syringe coverage had reduced odds of recent infection (AOR 0.32, 95% CI 0.10-1.00, p=0.050). In the Greater Glasgow and Clyde region only, there were reduced odds of recent infection among those currently receiving OST, relative to those on OST in the last six months but not currently (AOR 0.04, 95% CI 0.001-1.07, p=0.055). The effect of combined uptake of OST and high needle/syringe coverage was only significant in unadjusted analyses (OR 0.34, 95% CI 0.12-0.97, p=0.043; AOR 0.48, 95% CI 0.16-1.48, p=0.203). The final analysis chapter built on the previous chapter investigating the association between uptake of harm reduction interventions and recent HCV infection, by using data from three sweeps of the NESI survey, undertaken in 2008-09, 2010 and 2011-12. A framework to triangulate different types of evidence – ‘group-level/ecological’ and ‘individual-level’ – was applied. Data on service provision (injecting equipment provision and methadone dispensation) were also collated and analysed.

Since 1980, the global prevalence of obesity has more than doubled. According to the World Health Organization (WHO) more than one in ten of the world’s adult population are now obese. The prevalence of obesity is high both in the developed and developing countries, leading to suggestions of an “obesity pandemic” or “globesity”. In Scotland alone, 28% of adults are now obese, and a further 36% are overweight. Historically, the main focus of healthcare has been the avoidance of preventable mortality. As life-expectancy has increased, attention has focused on the need to improve health, as well as longevity. The WHO definition of health encompasses mental and social, as well as physical, well-being. It is widely accepted that obesity causes, or aggravates, a number of medical conditions, and is also associated with reduced life-expectancy. However, the research on adiposity and subjective well-being is still in its infancy and previous studies suggest that the relationship is complex. This thesis starts by demonstrating the importance of subjective well-being in terms of its association with adverse outcomes: all-cause death, coronary heart disease (CHD), cancer incidence, and psychiatric hospitalisations. This is followed by six complementary studies that explore the relationship between adiposity and subjective well-being. Subjective well-being is explored using various approaches including self-reported health (SRH), health-related quality of life (overall, physical and mental/psychosocial), mental health and mood disorder, and adiposity is assessed using four measures: body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR) and body fat percentage (BF%) across the whole range of adiposity (from underweight to class III obese).

This thesis traces the antecedents of the World Health Organization (WHO) back to the establishment of the League of Nations in 1920. The 1946 Constitution of WHO specifies two prime functions for the Organization – technical assistance to countries and cooperation with governments to strengthen national health services. The thesis analyses how international health work in the interwar years moved towards these tasks by studying the intersecting careers of Melville Mackenzie and Ludwik Rajchman. The analysis begins with relief and reconstruction in Russia in 1921-1923, extends to technical assistance to Greece and Bolivia in 1928-1930 and concludes with technical cooperation with China over the period 1930 to 1941. The viewpoint of the thesis is that of international staff working within the borders of sovereign states. The thesis reveals that policy documents drafted by the League of Nations Health Organisation between 1943 and 1945 defined the prime objective of an international health organization as being 'the promoting of health for all'. These documents also provided the basis of the Constitution of WHO, including its frequently-quoted definition of health. Mackenzie presented the WHO Constitution for approval to delegates attending the 1946 International Health Conference in New York and signed it on behalf of the United Kingdom, with authority that was unprecedented for a physician. The thesis uses a genealogical metaphor in exploring the origins of UNICEF and WHO. This shows the lineage of the former going back to generously funded agencies which supplied countries with health resources and resident international personnel. WHO, which originated from agencies that received scaled contributions from governments, lacked funds to engage, significantly, in technical cooperation with individual countries in the immediate postwar period. In 1948, an enduring and effective cooperation was established between UNICEF and WHO, as a consequence of a rivalry. Mackenzie and Rajchman are shown to have been at the heart of this. The thesis concludes by suggesting that international cooperation with countries to strengthen national health services might be improved by studying the interwar initiatives of Mackenzie and Rajchman.

Background: Despite the important, and well-established, link between poverty and poor health, previous research has shown that there is an ‘excess’ level of mortality in Scotland compared to England and Wales: that is, higher mortality seemingly not explained by differences in levels of socio-economic deprivation. This excess has been shown to be ubiquitous in Scotland, but greatest in and around Glasgow and the West Central Scotland conurbation. To investigate this further, the aims of this research were: first, to compare levels of mortality and deprivation – and, specifically, the extent to which differences in the latter explain differences in the former – between Glasgow and its two most comparable English cities, Liverpool and Manchester; and second, to investigate, by means of collection and analyses of new population survey data, some of the many hypotheses that have been proposed to explain Scotland’s, and Glasgow’s, ‘excess’ levels of poor health. Methods: Geographic Information System (GIS) software was used to create small geographical units for Glasgow comparable in size to those available for the English cities (average population size: 1,600). Rates of ‘income deprivation’ were calculated for these small areas across all three cities. All-cause and cause-specific standardised mortality ratios were calculated for Glasgow relative to Liverpool and Manchester, standardising for age, sex and income deprivation decile. In addition, a range of historical socio-economic and mortality data was analysed. Three of the previously suggested explanations for excess Scottish mortality were investigated: lower levels of social capital; a lower ‘Sense of Coherence’(SoC); and a different ‘psychological outlook’ (specifically, lower levels of optimism). To do so, a representative survey of the adult population of Glasgow, Liverpool and Manchester was undertaken. Previously validated question sets and scales were used to measure the three hypotheses: levels of social capital were assessed by means of an expanded version of the Office for National Statistics (ONS) core ‘Social Capital Harmonised Question Set’ (covering views about the local area, civic participation, social networks and support, social participation, and reciprocity and trust); SoC was measured by Antonovsky’s 13-item scale (SOC-13); and levels of optimism were assessed using the Life Orientation Test (Revised) (LOT-R). The data were analysed by means of multivariate regression analyses, thus ensuring that any observed differences between the cities were independent of differences in the characteristics of the survey samples (age, gender, social class, ethnicity etc.). Results: The deprivation profiles of Glasgow, Liverpool and Manchester were shown to be very similar: approximately a quarter of the total population of each city was classed as income deprived in 2005, with the distributions of deprivation across the cities’ small areas also extremely alike. Despite this, after statistical adjustment for any remaining differences in deprivation, premature deaths (<65 years) in the period 2003-07 were 30% higher in Glasgow compared to Liverpool and Manchester, with deaths at all ages almost 15% higher. This excess was seen across virtually the whole population: all adult age groups, males and females, and among those living in deprived and non-deprived neighbourhoods. However, a difference was observed between the excess for deaths at all ages and that for premature deaths. For the former, the 15% higher mortality was distributed fairly evenly across deprivation deciles, and the greatest contribution (in terms of causes of death) was from cancers and diseases of the circulatory system; in the latter case, the excess was much higher in comparisons of those living in the more, rather than less, deprived areas (particularly men), and was driven in particular by higher rates of death from alcohol, drugs and suicide. Importantly, the excess appears to be increasing over time. The analyses of the survey data showed SoC to be higher, not lower, among the Glasgow sample compared to those in both English cities. Levels of optimism (measured by the LOT-R scale) were very similar in Glasgow and Liverpool, and higher than that measured among the Manchester sample. Although not all aspects of social capital presented the Glasgow sample in a more negative light, Glasgow respondents were, however, characterised by lower levels of social participation, trust and reciprocity. A number of these differences were greatest in comparisons of those of higher, rather than lower, socio-economic status. Conclusions: As currently measured, socio-economic deprivation does not appear to explain the differences in mortality between the cities: there is a high level of ‘excess’ mortality in Glasgow compared to the English cities. While many theories have been proposed to explain this, on the basis of the analyses included within this thesis, it seems highly unlikely that two of these – lower Sense of Coherence and a different psychological outlook (optimism) – play a part. However, it is possible that differences in aspects of social capital may play a role in explaining some of the excess, particularly that observed in comparisons of less deprived populations. The concluding chapter of the thesis argues that excess mortality in Scotland and, in particular, its largest city, is a deeply complex phenomenon: the causes, therefore, are likely to be equally complex and multifactorial. It is postulated that, given the fundamental link between deprivation and mortality, the essence and reality of deprivation experienced by sections of Glasgow’s population may not have been fully captured by the measures employed within research to date. More speculatively, the role of history may be important in seeking to identify the potentially different, unmeasured, facets of deprivation experienced by people in Glasgow compared to those in Liverpool and Manchester. It is also possible that protective factors (relating to, for example, ethnicity and social capital) may be at work in the two comparator English cities. However, given that excess mortality has been shown for all parts of Scotland compared to England & Wales, and not just Glasgow, this is not in any way a complete explanation.