X-ray scattering studies of compound semiconductors

In this thesis, techniques of high resolution x-ray diffraction, topography and grazing incidence reflectivity have been employed in order to gain information on compound semiconductors. A recent growth technique. Vertical Gradient Freeze (VGF), has been investigated for 2" InP wafers, and been found to produce virtually dislocation- free crystals. In the one wafer where dislocations have been imaged, they have a density of ~200cm(^-2), with Burgers vectors lying in the plane of the wafer. This is in contrast to topographs of Liquid Encapsulated Czochralski (LEG) InP, where a dislocation density of up to 6.10'(^4)cm(^-2) was observed at the wafer periphery. No growth striations were observed in VGF samples, implying a planar solid-melt interface. VGF GaAs wafers are seen to be virtually dislocation free when Si doped, have dislocation densities of 900cm(^-2) when undoped and 1200cm(^-2) when Zn doped. Triple axis diffraction measurements showed a variation in tilts between/samples, but no strain variation. The tilt variation was attributed to the polishing process. Asymmetric scans showed a variation in strain at high tilts. These data have been used to form a model for the crystal surface: mosaic blocks of perfect crystal surrounded by low angle boundaries consisting of rows of edge dislocations. During the polishing process, these blocks are physically rotated, evidence for which is supplied from analysis of the specular part of reflectivity scans. Specular and diffuse reflectivity scans on InP substrates have been simulated using the Distorted Wave Born Approximation (DWBA). In all cases a 30Å thick oxide layer was identified on the sample surface. In order to obtain a good simulation for transverse scans at two values of q(_z), it was necessary to include a grading in electron density at the top surface. Epitaxial layers of Hg(_1-x)Mn(_x)Te (MMT) grown by the Interdiffused Multilayer Process (IMP) on GaAs with a CdTe buffer layer have been characterised using double and triple axis diffraction. Although reasonable compositional uniformity was observed across the wafers (from 0.3%mm(^-1)), dynamical simulations of pseudo-triple axis scans showed a grading in composition with depth. It was observed that the crystalline perfection deteriorated with increased Mn fraction. The MMT and CdTe layers were almost fully relaxed, and were found to have dislocation densities of l0(^7)-l0(^9)cm(^-2). In one sample the presence of zinc blende MnTe was established using double axis diffraction. Finally, the high intensity of the European Synchrotron Radiation Facility (ESRF) has been exploited in order to topograph highly absorbing materials. The effect of heater failure in the growth of GaAs in space has been shown to produce high levels of strain and twinning. It has also been shown topographically that contact with the crucible during the growth of GaInSb from the melt leads to increased strain, so de-wetting phenomena improve crystalline growth

Aquaculture site selection Report

Report on potential, selected sites for offshore aquaculture along the Spanish, Norwegian and Irish Atlantic coasts. European policy intends to expand the space available to aquaculture by cultivating sites that are offshore. This presents challenges in terms of building structures e.g. fish cages that withstand the effects of offshore weather conditions along the Atlantic coast. In order to establish possible future sites for offshore aquaculture production we intend to gather relevant wave, current velocity and water column structure measurements from the coasts of Ireland, Norway and Spain and use these data to validate site assessment models at ca. 200 m horizontal resolution of the potential new offshore aquaculture sites. This will result in a generic tool based on in-situ observations and model output over a hindcast period, coupled to existing site decision tools, so that potential license applicants can pinpoint sites for further exploration and site investigation

Effect of changes in moderate or vigorous physical activity on changes in health-related quality of life of elderly British women over seven years.

PURPOSE: This study investigates the effect of changes in moderate or vigorous physical activity (MVPA) on trajectories in health-related quality of life (HR-QoL) over 7 years in British elderly women. METHODS: A total of 1,926 women from the British Women's Heart and Health Study with information on MVPA and HR-QoL [measured using Euro quality of life 5 dimension (EQ-5D)] at baseline and at 7 years of follow-up were included in the analysis. Baseline and 7-year follow-up MVPA values were categorised into 3 groups, generating 9 categories of change in MVPA. Logistic regression was used to obtain odds ratios (ORs) of maintaining or improving HR-QoL according to different patterns of change in MVPA level. RESULTS: Women who remained inactive over the 7 years of follow-up had the largest reduction in their EQ-5D scores. Compared to these women, women that increased their MPVA level from "inactive" to "low" or to "moderate-high" were more likely to maintain or improve their HR-QoL over 7 years (ORs 1.65 or 2.70, respectively, p value for trend <0.001). After adjustment for baseline EQ-5D score and a wide range of potential confounders, results remained largely unchanged, though precision of the estimates generally decreased. CONCLUSIONS: Our findings suggest that relatively regular MVPA, even taken up later in life, can help older women prevent a decline in HR-QoL and even improve their enjoyment of life

Organizations’ Perception of Service-Learning Study Abroad Programs and Transformational Partnerships

Global education is becoming increasingly important in higher education institutions in the United States. Concurrently, service-learning is another educational activity becoming more popular in higher education institutions. Very little research has been done on the impact on the community from a service-learning perspective, especially as a part of a study abroad. The purpose of this study was to explore the impacts of a short-term service-learning study abroad program on the community partners (organizations) where students completed service-learning. Semi-structured interviews were conducted with leaders of organizations in Ireland who hosted students from the University of Florida during a study abroad program. Data were interpreted using Enos and Morton’s (2003) campus and community partnerships framework. Results revealed both transactional and transformational outcomes. Long-term impacts included cultural exchanges, the skill level of students, and moving partnerships forward. Recommendations for practice and research are provided

Moving Beyond Short-Term Impacts of Service-Learning Study Abroad Program on Students’ Transformation: An Irish Case Study

The purpose of this study was to better understand the impacts on students who participate in short-term service-learning study abroad programs. Using Mezirow’s theory of Transformational Learning as a guide, students were interviewed on the lasting impacts that the program had on their transformation. Student participated in semi-structured interviews lasting in length of 30 minutes to an hour. These interviews took place approximately 7 months after the completion of their study abroad program. Student’s transformation was categorized into the 4 main areas of transformation according to Mezirow (1991): refining meaning schemes, learning new schemes, transforming schemes, and transforming perspectives

Effect of changes in moderate or vigorous physical activity on changes in health-related quality of life of elderly British women over seven years.

PURPOSE: This study investigates the effect of changes in moderate or vigorous physical activity (MVPA) on trajectories in health-related quality of life (HR-QoL) over 7 years in British elderly women. METHODS: A total of 1,926 women from the British Women's Heart and Health Study with information on MVPA and HR-QoL [measured using Euro quality of life 5 dimension (EQ-5D)] at baseline and at 7 years of follow-up were included in the analysis. Baseline and 7-year follow-up MVPA values were categorised into 3 groups, generating 9 categories of change in MVPA. Logistic regression was used to obtain odds ratios (ORs) of maintaining or improving HR-QoL according to different patterns of change in MVPA level. RESULTS: Women who remained inactive over the 7 years of follow-up had the largest reduction in their EQ-5D scores. Compared to these women, women that increased their MPVA level from "inactive" to "low" or to "moderate-high" were more likely to maintain or improve their HR-QoL over 7 years (ORs 1.65 or 2.70, respectively, p value for trend <0.001). After adjustment for baseline EQ-5D score and a wide range of potential confounders, results remained largely unchanged, though precision of the estimates generally decreased. CONCLUSIONS: Our findings suggest that relatively regular MVPA, even taken up later in life, can help older women prevent a decline in HR-QoL and even improve their enjoyment of life

Effects of plant-based diets on weight status: A systematic review

There is an increasing number of people who convert to a plant-based diet. The desire for health benefits, including weight management, is often a contributing factor behind this dietary choice. The purpose of this review was to evaluate intervention studies assessing the effects of different plant-based diets on body mass index and weight. A literature search was conducted in PubMed until December 2019. Twenty-two publications from 19 studies were included. The majority of them were randomized controlled trials comparing a low-fat vegan diet to an omnivore diet in participants with overweight, type 2 diabetes mellitus and/or cardiovascular disease. All studies reported weight reductions, of which seven revealed significant differences, and four revealed non-significant differences between the intervention and the control groups. The results suggest that plant-based diets may improve weight status in some patient groups. Due to restrictions in fat intake in many studies, followed by reduced energy intake, the effects of the different interventions differ depending on the specific plant-based diets investigated. Future research should aim to include a representative study population and apply study diets without dietary restrictions.publishedVersio

Few U.S. public health schools offer courses on palliative and end-of-life care policy

Background: Palliative care has been identified by the World Health Organization (WHO) as a critical policy element for the relief of suffering, yet palliative care policy receives minimal attention in mainstream U.S. public health journals, conferences, or textbooks. In the ’90s, documentation of the lack of attention to end-of-life and palliative care in medical and nursing curricula led to concerted efforts to improve medical and nursing education in palliative care. No such educational effort has yet been directed toward public health professionals. Objective: This study\u27s objective was to quantify current course offerings covering palliative and end-of-life care from a public health and health policy perspective at accredited schools of public health. Design: Using a list of keywords about palliative and end-of-life care, the research team searched publicly accessible websites of all CEPH accredited and affiliated U.S. schools of public health to identify courses that included relevant content about palliative care. Results: For academic years 2011/12 and 2012/13, 3 (6%) of the 49 accredited U.S. schools of public health offered a full course covering public health issues in palliative care. Six schools (12%) included some palliative care content in related courses such as gerontology policy. Conclusions: Schools of public health are not preparing future policy experts with a basic knowledge of the components and systems of palliative care and hospice. Development and dissemination of appropriate curricular material to address the public health and policy aspects of palliative care is needed to address this gap