Doctor of Philosophy

dissertationWhile the healthy hip provides decades of pain free articulation, the cartilage and labrum may degenerate during the process of osteoarthritis (OA). Most hip OA is caused by subtle pathomorphologies, including acetabular dysplasia and acetabular retroversion. The link between pathomorphology and OA is thought to be mechanical, but the mechanics have not been quantified. The aim of this dissertation was to provide insight into the pathogenesis of hip OA via finite element (FE) modeling. The objectives were two-fold: to validate a subject-specific modeling protocol for a series of specimens and assess the effects of assumptions on model predictions, and to use the modeling protocol to evaluate soft tissue mechanics in pathomorphologic hips in comparison to normal hips. For the first objective, FE predictions of contact stress and contact area were directly validated for five cadaveric specimens, and the specimen- and region-specific hyperelastic material behavior of cartilage was determined. FE predictions of contact stress and contact area were in good agreement with experimental results, and were relatively insensitive to the assumed cartilage constitutive model. There were distinct regional differences in the hyperelastic material behavior of human hip cartilage, with stiffer lateral than medial cartilage and stiffer acetabular than femoral cartilage. In order to investigate the mechanical link between pathomorphology and hip OA, FE models of ten hips with normal morphology, ten hips with acetabular dysplasia and ten hips with acetabular retroversion were generated. FE models of dysplastic acetabula demonstrated the importance of the acetabular labrum in load support in the dysplastic hip. FE models of retroverted acetabula demonstrated distinct superomedial contact patterns in comparison to distributed contact patterns in the normal hip. Finally, the effects of cartilage constitutive model on predictions of transchondral maximum shear stress and first principal strain were evaluated. In contrast to contact stress and contact area, maximum shear stress and first principal strain were sensitive to the cartilage constitutive model. Overall, this dissertation provides novel insights into the contact mechanics of pathomorphologic hips that may be important in the pathogenesis of OA, as well as the technical foundation for studies evaluating additional mechanical variables in the human hip

Research protocol for the exploration of experiences of aboriginal Australian mothers and healthcare professionals when using the Edinburgh postnatal depression scale:A process-oriented validation study using triangulated participatory mixed methods

INTRODUCTION: Adopting a process-oriented framework for test validation can help to establish whether this tool has the potential to be an acceptable, valid and reliable indicator of depression for mothers and mothers-to-be. This mixed-methods research protocol seeks to explore the views and experiences of Aboriginal mothers and healthcare professionals in relation to the Edinburgh Postnatal Depression Scale (EPDS), and is intended to highlight potential barriers in perinatal mental health conceptualisation, engagement and response style. METHODS AND ANALYSIS: Thematic analysis will be applied to interview transcripts of Aboriginal Australian mothers (n=6+) and healthcare professionals (n=6+) to identify key themes. The process-focused validation model will use narratives about experiences of using the EPDS as the priority point of analysis. Item-level data and process-level (experience) data are key phenomenological data. The interview-based narratives will be then compared with EPDS scores to check for points of congruence and divergence. This will be done at two time points, antenatally and postnatally, to assess changes in assessment processes and perceptions. Bridging evidence-based research with clinical practice in an Aboriginal Australian context will be facilitated by an investigation of the perceived cultural relevance and likely clinical effectiveness of EPDS. Such evidence is critical to understanding whether the EPDS fulfils its intended purpose. The guiding principles in designing this research protocol is to benefit the well-being of young Aboriginal families and communities through partnership with Aboriginal women. ETHICS AND DISSEMINATION: Ethics approval was obtained from Human Research Ethics Committee of Murdoch University and from Western Australian Aboriginal Health Ethics Committee (WAAHEC). Participating healthcare sites and services have provided letters of support. Results of this study will be submitted for publication in a peer-reviewed journal

Effect of bilingual education on students’ first language written discourse: a contrastive Spanish-English study using systemic functional linguistics

This thesis investigates whether studying through English has an effect on the written texts secondary school students produce in their first language, Spanish. Research in bilingual education has tended to focus on students‟ language proficiency and academic achievement as opposed to investigating differences in discourse norms. However, an increased awareness of the role of discourse in language use and the culturally-specific nature of discourse, along with a growing concern over the dominance of the English language in Europe and elsewhere, have widened the range of questions identified as requiring investigation in bilingual education. Popular understanding suggests that English speakers make different choices from Spanish speakers in particular rhetorical situations. Although research into these contrasts can be problematic, there is support for the existence of cultural preference in the selection of options, and specific areas of similarity and difference between Spanish and English discourse have been suggested. This study then looks at one group of secondary three (3º E.S.O.) Spanish students studying through English on a Content and Language Integrated Learning (CLIL) programme in Spain, and compares two sets of argumentative texts written in Spanish by the CLIL students with equivalent texts written by non-CLIL students in the same school. Forty-eight texts are examined in total, and the comparison draws on previous research into discourse differences between Spanish and English texts from contrastive rhetoric, systemic functional linguistics (SFL), and other fields, using tools from SFL for the textual analysis. Areas of analysis include use of clause complexes, multiple Theme and thematic progression, and also genre structure and text organisation strategies for argumentative writing. The main contrasts are found to be in length of t-units, use of simplexes versus complexes, use of multiple Theme, and some issues of text structure. These differences largely correspond to contrasts found in studies comparing written Spanish and written English text, with the CLIL students‟ texts showing features more commonly associated with English writing. Additional data from analysis of the geography textbooks used by the CLIL and non-CLIL students, questionnaires administered to these students, and interviews with their teachers are also used to explore the possible CLIL effect on the students‟ written text. The study discusses how discourse conventions associated with English text in contrast with Spanish text may have influenced the Spanish writing of the CLIL students, considering possibilities including the effect of direct and indirect teaching, and the more general impact of the CLIL programme. Also explored is the question of whether this possible influence of English on Spanish language use is a matter for concern or not, with increased work on language and discourse awareness suggested as a potential response. Methodological issues raised through the study relating to aspects of text analysis and of data collection are also addressed

Doing no harm:Addressing the quality of evidence in translating research to practice in preliminary research fields

Many countries are grappling with the dilemma of a growing gap between healthcare need and resource available. This gap is compounded by our collective and growing success in finding new treatments and potential interventions, many of them costly. There is no obvious solution for this conundrum

Executive functioning (fully) and processing speed (mostly) mediate intelligence deficits in children born very preterm

Children born very preterm (<32 weeks gestational age) are known to be at increased risk of neurocognitive impairments, in domains including executive functioning, processing speed, and fluid and crystallised intelligence. Given the close association between these constructs, the current study investigated a specific model, namely whether executive functioning and/or processing speed mediates the relationship between preterm birth and intelligence. Participants were 204 children born very preterm and 98 full-term children, who completed a battery of tasks measuring executive functioning, processing speed, and fluid and crystallised intelligence. Independent-samples t-tests found significantly poorer performance by children born preterm on all measures, and a confirmatory factor analysis found preterm birth to be significantly related to each of the cognitive domains. A latent-variable mediation model found that executive functioning fully mediated the associations between preterm birth and both fluid and crystallised intelligence. Processing speed fully mediated the preterm birth-fluid intelligence association, but only partially mediated the preterm birth-crystallised intelligence association. Future research should consider a longitudinal study design to test whether these deficits and mediating effects remain throughout childhood and adolescence

Mental health Gap Action Programme Intervention Guide (mhGAP-IG) for child and adolescent Mental Health in Low- and Middle-Income Countries (LMIC):A systematic review

BACKGROUND: The Mental Health Gap Action Programme (mhGAP) supports engagement of non-specialists in mental health services in Low- and Middle-Income countries. Given this aim, assessment of the effectiveness of approaches under its remit is warranted. AIMS: We evaluated mhGAP approaches relating to child and adolescent mental health, focusing on provider / child outcomes, and barriers / facilitators of implementation. METHODS: Thirteen databases were searched for reviews and primary research on mhGAP roll out for child and adolescent mental health. RESULTS: Twelve studies were reviewed. Provider-level outcomes were restricted to knowledge gains, with limited evidence of other effects. Child-level outcomes included improved access to care, enhanced functioning and socio-emotional well-being. Organisational factors, clients and providers? attitudes and expectations, and transcultural considerations were barriers. CONCLUSIONS: Further attention to the practical and methodological aspects of implementation of evaluation may improve the quality of evidence of the effectiveness of approaches under its remit

Doing ethical research together:A communitarian toolkit for ethical research beyond borders

The toolkit for ethical research developed out of a research project that focused on establishing place-based, community-centred best practice in grand challenges-related research ethics, integrity and conduct. We held 5 roundtable events at The University of Edinburgh drawing together more than 200 researchers from 30 countries and more than 60 discipline areas. These conversations highlighted that we needed a clarifying worldview to support place-based, community-centred, ethical action at every stage of the research journey. In response, we created a toolkit - accessible and practical material to guide people involved in complex community-based research. This toolkit explores an ethical worldview for research and provides practical guidance and questions to consider at every stage of the research journey, from developing an ethical research question through to being accountable for the legacy of your research long after the project has concluded

Maturation of auditory temporal integration and inhibition assessed with event-related potentials (ERPs)

Background: We examined development of auditory temporal integration and inhibition by assessing electrophysiological responses to tone pairs separated by interstimulus intervals (ISIs) of 25, 50, 100, 200, 400, and 800 ms in 28 children aged 7 to 9 years, and 15 adults.Results: In adults a distinct neural response was elicited to tones presented at ISIs of 25 ms or longer, whereas in children this was only seen in response to tones presented at ISIs above 100 ms. In adults, late N1 amplitude was larger for the second tone of the tone pair when separated by ISIs as short as 100 ms, consistent with the perceptual integration of successive stimuli within the temporal window of integration. In contrast, children showed enhanced negativity only when tone pairs were separated by ISIs of 200 ms. In children, the amplitude of the P1 component was attenuated at ISIs below 200 ms, consistent with a refractory process.Conclusions: These results indicate that adults integrate sequential auditory information into smaller temporal segments than children. These results suggest that there are marked maturational changes from childhood to adulthood in the perceptual processes underpinning the grouping of incoming auditory sensory information, and that electrophysiological measures provide a sensitive, non-invasive method allowing further examination of these changes

Key Issues of Research Ethics and Integrity in Global Challenges Research: A Scoping Review Protocol

Global challenges research brings with it the challenge of integrating diverse cultural and disciplinary perspectives in the service of addressing persistent and complex problems. In fragile and resource poor contexts this also brings with it a swathe of operational, legal and logistic challenges which can generate ethical conflicts. A scoping review is needed to identify key issues of research ethics and integrity, as well as strategies that have been brought to bear in an effort to resolve them. This protocol followed Prisma guidelines for Scoping Reviews (Prisma-ScR) and provides details of the review scope and parameters