12,113 results for Doctoral

  • A Mixed-Methods Evaluation of a Universal Group Parenting Programme for Parents of Adolescents

    Chu, Joanna (2014)

    Doctoral thesis
    The University of Auckland Library

    Scholars and policy makers have repeatedly advocated for the need to adopt a public health approach to supporting parents of adolescents in order to improve family functioning and prevent or reduce rates of adolescent problem behaviours. The aim of the approach is to enhance parenting practices, competencies, and adjustment for all parents, and to promote the well-being of their adolescent at the population level. However, there remain many gaps in the current literature that need to be addressed before moving towards a successful public health approach. These include a lack of evidence-based parenting programmes for parents of adolescents, the lack of adolescent input in parenting intervention research, and finally a lack of social validation on parenting programmes. To justify the need for a public health approach to supporting parents of adolescents, this study aimed to fill gaps in the literature in relation to the efficacy and social validity of parenting programmes for parents of adolescents. A mixed-methods design was utilised to evaluate the impact of a universal group parenting programme designed specifically for parents of adolescents ??? Group Teen Triple P (GTTP). First, a randomised controlled trial was conducted to examine the efficacy of the programme with 72 families drawn from the community. Data on parent- and adolescentrelated outcomes were collected from parents and adolescents at three time points (pre-, post- , 6-month follow up). The findings demonstrated that GTTP was effective in promoting positive parenting practices, reducing adolescent problem behaviours, and enhancing family functioning. Second, discussion groups were utilised to obtain parents??? and adolescents??? perspectives on the social validity of GTTP. The findings indicated that GTTP was beneficial and of value to parents and adolescents. Collectively, the findings suggest that parenting programmes such as GTTP are effective and socially valid for parents of adolescents. Implications for moving towards a public health approach are discussed in this thesis.

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  • Approaches to Multiscale Inverse Problems

    Nicholson, Ruanui (2016)

    Doctoral thesis
    The University of Auckland Library

    Many scientific problems involve parameters such as conductivity, permeability or density which vary on multiple spatial and/or temporal scales. When such a parameter is to be estimated from noisy indirect measurements we face a challenging dichotomy: In practical situations the computational cost required to accurately take into account the small scale behaviour can be prohibitive. On the other hand, estimation of the conductivity is an ill-posed inverse problem meaning that any modelling errors, such as neglecting the small scale, which are not accounted for can render estimate useless. A typical way of reducing the computational cost is to simply neglect any behaviour at the smaller scales, enabling a coarse discretisation of the problem. However, if the effects of disregarding smaller scale characteristics along with the coarse discretisation are not taken into account the estimates attained can be misleading. In this thesis, we develop computationally feasible models to tackle the problem of estimating the multiscale distributed parameter of the Poisson equation, which is closely related to the multiscale electrical impedance tomography (EIT) problem. In the case of estimating a low dimensional representation of the conductivity (devoid of the small scale features) we show that by applying the Bayesian approximation error (BAE) approach to marginalise over small scale effects and discretisation errors we are able to substantially reduce the dimension of the problem while maintaining accurate estimates. Moreover, we show that by applying a feature extraction type modification to the BAE approach we can in some cases estimate the amplitude and correlation length of the small scale component of the conductivity. In the case of estimating the full multiscale conductivity we show that multiscale finite element methods (MsFEM) can be implemented at both the forward modelling stage and at the inversion stage, which along with a somewhat coarsened discretisation can reduce overall computational cost. By deriving a closed form expression for the Jacobian matrix which represents the rate at which the electric potential calculated using MsFEM changes with respect to the conductivity we are able to apply gradient based optimisation techniques to estimate the conductivity. The BAE approach was also implemented in this procedure to take into account any modelling discrepancy caused by the use of MsFEM and discretisation errors. Use of such a procedure leads to estimates attained by using 7 multiscale basis functions in line with those calculated using finite elements on 85 linear basis functions.

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  • Development of Functional Polymer-Graphene Nanocomposites

    Mohan, Velram (2016)

    Doctoral thesis
    The University of Auckland Library

    This research focuses on the synthesis and characterisation of reduced graphene oxide (GO), systematically varying and identifying factors that are responsible for changing electrical conductivity and integrating the best reduced graphene oxide (rGO) results into a number of composite systems. Five different reducing agents (hydroiodic acid, hydrazine hydrate, hydrobromic acid, sodium borohydride and dextrose) were systematically investigated to identify the type of reducing agent and the process that provides reduced graphene oxide with superior chemical, physical and mechanical properties. Best results were obtained for a graphene oxide film reduced with hydroiodic acid, with the electrical conductivity of 103 S.cm-1 and better flexibility compared to those of films obtained by other reducing agents. Functionalising graphene oxide with electron donor and acceptors further improved the electrical conductivity. This functionalised graphene oxide (fGO) samples have been characterised to understand their physical and chemical properties. Mechanical exfoliation of rGO films using the ???scotch tape method??? has shown that as films become thinner, conductivity increases. It has been proposed that this is mainly due to the selective removal of less-pure rGO by the tape and this hypothesis has been supported by XPS and confocal microscopy results. Hybrid composites of polymer/polymer/graphene derivatives have been developed focusing on electrical conductivity and mechanical properties. Polypropylene, poly(methyl methacrylate) and polyoxymethylene were used as polymer matrices with polypyrrole and polyaniline as secondary conducting polymers. Graphene (G) and rGO were used as reinforcements. The maximum electrical conductivity of 0.85 S.cm-1 was achieved for a polyoxymethylene/polypyrrole/graphene blend with 2 wt.% and 4 wt.% of polypyrrole and graphene loading. Highly conductive rGO has also been used as a conductive coating on glass, flax and polypropylene yarns using binding materials (epoxy resin and thermoplastic starch solution) and a dip-coating process. Three different dip-coating processes have been developed to identify an efficient method of coating in terms of improving electrical conductivity. Glass fibre yarns (with epoxy binder and rGO) have been identified as having the highest electrical conductivity of 0.1 S.cm-1.

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  • ???It takes a village to raise a child???: Pastoral Care for M??ori and Pasifika secondary school students

    Barber, Charmaine (2016)

    Doctoral thesis
    The University of Auckland Library

    There is a paucity of research on pastoral care in New Zealand schools, yet the extant literature endorses the value of pastoral care for secondary students. For M??ori and Pasifika students, pastoral care may enable the blending of M??ori/Pasifika models of health/wellbeing with socio-ecological models such as that of Bronfenbrenner (1979), in the school context. Improved student wellbeing could foster better school retention and participation. Pastoral care, therefore, holds potential to be the nexus of health and educational needs in the school setting for the increasingly diverse secondary student population. The purpose of this study was to explore and interpret what pastoral care is in the New Zealand context, how it is understood, as well as how it is represented and co-ordinated both within and beyond the school environment. A case study design was used to research this phenomenon utilizing interviews, observations and document analysis. The study found that the commonalities, as well as the notable differences both inter- and intra- ethnically within M??ori and Pasifika populations necessitate additional professional development in cultural responsiveness for all school staff, and other adults contributing to the school context. Culturally responsive pastoral care for students encompassing the whole child, and their families, looks likely to be the essence of a more nurturing school environment. In relation, M??ori and Pasifika student voice indicated that they require improved processes in order to increase participation, engagement and retention at school. Students in lower decile schools will need increased funding in order to compensate for the layers of disadvantage that are predominantly anchored in historical inequities, but persist through the perpetuation of discriminatory structural inadequacies. The findings argue that these disparities need addressing with a fresh approach in order to benefit M??ori and Pasifika students, but also New Zealand society at large.

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  • Development and application of locally resonant metamaterials for acoustic barriers

    Hall, Andrew (2013)

    Doctoral thesis
    The University of Auckland Library

    There is increasing concern in New Zealand and overseas about inadequate sound insulation in buildings and the implications for occupants??? health and well-being both in the public and commercial sector. The application of metamaterials or structured material principles to this problem has produced a new isolation concept known as locally resonant structures (LRS). LRS combine interacting components specifically arranged to generate localised resonances within the structure and have exceptional sound transmission loss (TL) performance in defined frequency bands. Low frequency noise (below 1 kHz) is where irritating acoustic intrusion frequently occurs but is both challenging and expensive to prevent with conventional solutions, and where the LRS is a potentially compact and relatively lightweight solution. In this thesis the first large scale implementation of a locally resonant elastic metamaterials is presented, targeted at practical applications in building. Lumped parameter mass models were used to understand how the components of the LRS can be manipulated to generate a designated TL performance spectrum. Designs with the desired TL characteristics were then modelled using FEA software, and samples were fabricated for testing. TL results obtained under normal incidence and diffuse field conditions showed that the highest performing network arrangements combined layers of multiple resonators with multiple resonances to increase system bandwidth. Samples yielded systems with attenuation peaks of 80dB over band widths approaching 350 Hz at frequencies well below 1 KHz under normal incidence conditions with good correspondence to modelling predictions. In diffuse field conditions samples showed large TL improvement over band widths of 300+ Hz, 7 to 20dB above that of a conventional panel. The resulting systems have the potential to provide significantly higher transmission loss at low frequencies than conventional wall systems of similar size and weight.

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  • Unpacking Heterotopic Social Space: An Ethnography of Urban Exploration

    Bingham, Kevin Peter (2017)

    Doctoral thesis
    University of Otago

    Urban exploration has emerged as the popular term used to describe the physical exploration of human-made structures and objects, particularly those that are abandoned or hidden from the public eye. In recent years it has received growing academic attention and has been examined in the current literature as a leisure form which produces a posture of authenticity that rejects commoditisation in its celebration of rebellion. While this work is certainly a useful and valuable start, it is evident that there is a distinct lack of critical research and many fundamental oversights as urban exploration is removed from its real contexts. This thesis takes the study of this phenomenon in a different direction by focusing its attention straight at the living and breathing individuals who call themselves urban explorers to lay bare a unique leisure world. Using as its starting point Foucault’s (1984) concept of heterotopia which is said to operate somewhere between the everyday world and the imaginary, this thesis unpacks the heterotopic social space of a group of urban explorers known as WildBoyz. At the same time, it takes into account the inescapable period of interregnum we currently find ourselves in. This is to move beyond the limits of extant studies by considering the shift into a world dominated by consumer capitalism, and the present social, cultural and political context in which urban exploration takes place. With this in mind, the thesis is an ethnographic investigation that combines the methods of hermeneutic sociology and sociological hermeneutics to enter a heterotopic social space which, including the researcher, comprised nine key individuals from North East England. By doing this, the thesis effectively delves into this heterotopia, and all of its quixotic qualities, of a group of urban explorers by unpacking how they control cognitive, aesthetic and moral social space, the life strategies they individually adopt and the significance of the ‘virtual’ as a further extension of their heterotopic world. In the end, what this nuanced perspective tells the reader is that a new way of understanding urban exploration has been developed, and this is one that views a particular kind of heterotopic reality as being a form of ‘devotional leisure’ (Blackshaw, 2017). In other words, this thesis offers instructive and comprehensive insights into the possibilities of freedom, the significance of performativity and the machinations of very particular type of ‘home’ that cannot help but always be temporary and on the move.

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  • Virtual Reality Interface Factors in a Power Wheelchair Simulator

    Alshaer, Abdulaziz (2017)

    Doctoral thesis
    University of Otago

    Power wheelchairs (PWCs) can improve users’ quality of life by enabling them to participate in the activities of daily living, decreasing their dependence on human assistance. PWC users are faced with restricted environments, with limited space to manoeuvre, and are therefore vulnerable to collisions and injuries. To use a PWC effectively and safely, individuals must undertake training and assessment of their competency. There is significant potential for the use of virtual reality in the training and assessment of PWC users. To date, there is no standard tool available for PWC assessment and training. Rather, clinics use their own observation measurer and assessment is often largely based on guesswork. Several simulators have been developed to help the training of PWC users, yet the study of virtual assessment is an under-researched area. In fact, most simulators offer only very limited functionality and rely solely on client-centric information. For the development of a useful simulator, it is important to identify and evaluate interface factors affecting perception, behaviour, experience, and driving performance from both the user’s and clinician’s perspectives. In this thesis, issues with current PWC simulators were identified and investigated, with the intention of providing a suitable research platform for the advancement of bringing PWC simulator into clinical use. The aspects investigated include the interaction device, perception and behaviour, and virtual assessment. Three systems were developed to test each of these areas by incorporating theories and techniques from computer science and human-computer interaction. The first experiment answered the question, “which input devices are necessary and appropriate, and which virtual input device representations can and should be implemented for PWC simulation?” A proprietary PWC joystick was compared to a standard gaming joystick, and driving performance and experience were measured. Four experimental conditions (comprising two virtual input modalities and their two real-world counterparts) were studied. The findings suggest that performance is enhanced when the PWC joystick is represented and that the gaming joystick is adequate for PWC simulation. The second study investigated the question, “how do immersion factors influence behaviour, perception and sense of presence when navigating a PWC simulator?” The evaluated immersion factors include display type (head mounted display vs. monitor), field of view (changeable vs. static), and avatar presence (present vs. absent). User perception (explicit judgement of doorframe passability) and embedded behaviour (implicit measure of gap passability) were measured, based on the user’s decisions during the experiment. The results show that all three factors affect the user’s sense of presence. The display type affected both perceptual and behavioural measures, whereas field of view only affected behavioural measures. The final experiment explored the question, “how accurately can clinicians assess driving tasks in the virtual environment compared to the real world?” This study evaluated the effect of three observational techniques (viewpoints) on clinician assessment of PWC driving tasks. In addition, perceived ease of use, confidence level, and sense of presence were also examined. Observational techniques include walk, orbit, and standard viewpoints. The findings of this study suggest that clinicians could make accurate judgments and experience a high confidence level when they were able to walk or orbit the viewpoint. The results from all experiments provide general design guidelines for future virtual reality applications, in particular, PWC simulator design.

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  • Dental trauma in New Zealand adults: a secondary analysis of national survey and ACC data

    Scott, Nina (2017)

    Doctoral thesis
    University of Otago

    Background Dental trauma is described by the World Health Organization as a worldwide major public health problem. However, little is known in New Zealand (NZ) and worldwide about the dental trauma experience of adults. Most studies of dental trauma prevalence, incidence and aetiology in NZ and overseas have been carried out using convenience samples, such as people attending a hospital dental clinic. The literature shows that a considerable amount of trauma to permanent teeth occurs at a young age. Since most damage to permanent teeth is not self-healing, injuries to permanent teeth and sequelae of the trauma can be carried into adulthood. Dental trauma is therefore a life-long burden for the individual adult and society. While there have been three National Oral Health Surveys in NZ, the 2009 survey was the first to collect information about dental trauma in the interview and examination. In NZ, visits to a dentist for dental trauma and subsequent treatment is recorded with the Accident Compensation Corporation (ACC), a compulsory social insurance scheme. To date, dental injury data recorded with the ACC have not been analysed with respect to outcomes. Purpose The objective of this study was to assess the prevalence, risk associations and impact of dental trauma of New Zealanders over 18 years old. Methods Information about dental trauma in a representative sample of NZ adults was collected as part of the 2009 NZOHS. This included self-reported information and a clinical examination of the six maxillary anterior teeth. Data were weighted and analysed using Stata. Data from a separate sample of NZ adults who had sustained dental trauma in 2008 and had the injury registered with the ACC were analysed using SPSS. Results Analysis of the 2009 NZOHS data showed that of the approximately 40% who reported previous orofacial trauma, 70% (that is, 28% overall) reported that this included a dental injury. More males than females had experienced orofacial trauma (51% and 31% respectively; P<0.05) but there was no sex difference in self-reported dental trauma. The most common injury was a “chipped or broken tooth” (67%). Almost three-quarters had sought treatment for their dental injury. Clinical examination revealed an overall trauma prevalence of 23%, with more males than females affected (27% and 20% respectively). Almost 15% had one injured tooth; 7% had two injured teeth and 2% had three or more. The central incisors were the most frequently affected. The most common clinical dental trauma observation was evidence of “treatment” or an “untreated enamel fracture”, more common among males and those aged 35-44. Analysis of dental information from the ACC revealed that 32,110 adults and children sought treatment for orofacial trauma during 2008. Dental injuries to permanent teeth most commonly involved the central and lateral maxillary incisors. Some 1,325 adults who sustained dental trauma during June 2008 were followed for the subsequent 5 years. Generally, more severe injuries required more treatment. Conclusion Prevalence estimates for and characteristics of dental trauma in NZ adults are similar to international findings. There were socio-demographic disparities in the occurrence and treatment of dental trauma in the NZ adult population. The findings confirmed that traumatic dental injuries in the New Zealand adult population constitute an important public health issue, given that many will need life-long follow-up and treatment.

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  • Coroners' Recommendations and Suicide Prevention in Specialist Mental Health Services

    Manuel, Jennifer Ann (2017)

    Doctoral thesis
    University of Otago

    Suicide is considered to be a serious health and social issue and the improvement of services that cater for those affected by mental disorder is one of the principal targets for suicide prevention. All cases of suspected suicide are investigated by a coroner in New Zealand and the key purposes of these inquiries is establishing the circumstances of death and making recommendations that may prevent a similar death occurring in the future. Specialist Mental Health Services (SMHS) are often involved in the inquiries and are recipients of the recommendations. However, to date there has been a very limited amount of research that has examined the impact of coronial recommendations on the delivery of SMHS. A two phase qualitative dominant descriptive mixed method design was used to conduct the study. The first phase involved the retrieval and content analysis of 136 coroners’ recommendations directed to SMHS that relate to cases of suicide. The second phase of the study aim to gain an understanding of how the recommendations are handled by SMHS and to explore the first phase themes from the perspective of SMHS and individuals that work with families in SMHS. This was investigated with semi-structured interviews of SMHS leaders that are responsible for the implementation of the recommendations across 12 DHBs in New Zealand, as well as a local family and whānau worker focus group. The first phase findings produced six major categories of coronial recommendations. These included communication, restrictive management, staff education, working with family, risk assessment, and service delivery. Further exploration of these categories from the perspective of SMHS leaders responsible for their implementation revealed that the majority of the recommendations were perceived as appropriate; however, concerns were raised regarding recommendations in the risk assessment and restrictive management categories. Overall the SMHS leaders portrayed the perspective that the recommendations have a limited positive influence on the delivery of SMHS and suicide prevention. The family and whānau worker focus group findings corroborated that coroners are accurately identifying significant shortcomings in the way SMHS are including families in the treatment of mental health consumers. The findings highlight that SMHS need to consider how they could improve their response to coronial recommendations that have clinical credibility, particularly in regard to communication, and family inclusive treatment. A starting point may be the promotion of a more positive, learning and transparent organisational culture. It is also essential that coroners promote organisational learning by consistently adopting a wider systematic focus during inquiries and avoid individual scrutiny of practice. Furthermore, better resourcing of Coronial Services of New Zealand may be required to ensure all recommendations have clinical relevance and take a more balanced and considered approach to risk, containment, and therapeutic autonomy.

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  • Oceanic nitrous oxide distribution and production a stable isotopic approach

    Mullungal, Muhammed Nayeem (2017)

    Doctoral thesis
    University of Otago

    Nitrous oxide (N2O) is a biogenic trace gas that has a significant role in global climate change, stratospheric chemistry and in the ocean nitrogen cycle. Its concentration in the ambient air has increased to the current value of 330 ppbv from 275 ppbv (pre-industrial period). The oceans are thought to account for 25-30 % of global N2O emissions. However, the biogeochemical pathways resulting in its formation are not well known. Two microbial pathways, nitrification and denitrification, dominate N2O production with their N2O source product varying with oxygen availability. There is a paucity of N2O data for many oceanic regions, and hence the global budget of N2O is not fully closed. This thesis describes the N2O distribution and its changes with AOU and nutrients along the selected regions in the Southwest Pacific Ocean (SWP) and Northeastern Arabian Sea (NEAS). The comparison of the oxygen minimum zones (OMZs) in NEAS with minimum oxygen concentrations of > 10 μM and the SWP Ocean with minimum oxygen concentrations > 130 μM reveals significant differences in the N2O cycling of both the regions, which is reflected in N2O saturations, dual isotope ratios and isotopomers. At coastal Otago Continental Shelf, N2O distribution was the highest during spring; [N2O], and saturations varied with MSTW > Neritic > SASW. In late autumn, an inverse trend in the distribution of N2O was observed. At the surface, saturations varied between 110 % - 130 % in spring, and it decreased below 100 % during autumn. The results indicate that the Otago coastal region is a source of atmospheric N2O. At the SWP open ocean stations, the minimum [N2O] was always found in the surface layer, with average N2O saturation values of 101 ± 1 % (winter), and 103 ± 1 % (spring) in the STSW, and 102.5 ± 0.5 % in the SASW. These values are similar to the global oceanic mean values (103.5%), derived by Bange et al. (2008). At the NAES, surface mixed layers were poorly oxygenated (20 – 120 µM) relative to the SWP, with a strong oxygen minimum zone (OMZ) present below the mixed layer (25 - 1000 m). The N2O water column distribution showed a single peak structure, with only one broad maximum at mid-depths. The surface saturations are 2 - 4 times higher than the SWP saturations at NAES. N2O sea to air (Fs-a) fluxes indicates that the SWP and NEAS is a source of N2O to the atmosphere, though the extent of the fluxes varies regionally and seasonally. In SWP, below the surface mixed layer [N2O] varied with depth. In the upper thermocline [DO] decreased below that of the surface water whereas [N2O] increased. Beneath the upper thermocline [N2O] in the AAIW increased coincident with an increase in [DO] except at the subantarctic SWP. The maximum [N2O] was found in the CPDW where DO was the minimum. At NEAS N2O saturation were 220 - 630 % in intermediate water (ICW) and 330-390 % in AAIW. A [DO] vs [N2O] inverse relationship and ∆N2O vs AOU positive correlation observed in the SWP as evidence for nitrification as the major formation pathway of N2O. Positive correlations between ∆N2O and nitrate (NO3-) provides further evidence for the nitrification process being the primary source of N2O. For the NAES, ∆N2O vs AOU and ∆N2O vs nitrate suggests formation primarily via nitrification. Stable isotopes and isotopomers of N2O provided more insight into the N2O formation pathways. The depletions in δ 15Nbulk and δ18O in the SWP surface mixed layer, minima in the subsurface, and enrichment at the bottom suggest nitrification, except in the subsurface 200-500 m. The NAES dual isotopes reflect the major role of nitrification especially in the surface and in the OMZ. These different oxygen isotope results suggest oxidation of hydroxylamine (NH2OH) followed by nitric oxide (NO) oxidation (during nitrification) at all depths in the SWP (except at 200-500 m) and NEAS. To examine the formation processes, Δ18O was also determined (δ18ON2O - δ18O of DO). Δ18O was almost constant at all depths for SWP waters, while it showed a minimum (roughly 9 ‰ lower than waters above and below) at 200-500 m except in subantarctic SWP waters. This observation proves the additional contribution to N2O source from nitrifier denitrification at 200-500m in the SWP (except in the subantarctic) and throughout the OMZ in the NEAS. The intramolecular distribution of isotopomers of 15N in N2O and S.P were also supportive of these findings.15N isotope labelled incubation experiments using 15NH4Cl and K15NO3 for the selected stations of Otago Continental Shelf transect also indicated that ammonium oxidation is the major process responsible for the production of N2O.

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  • A crying shame : affect, emotion and welfare receipt in New Zealand.

    Gray, Claire (2017)

    Doctoral thesis
    University of Canterbury Library

    This thesis focuses attention on the welfare setting in New Zealand where welfare policy is administered and put into practice. Within the thesis, I analyse focus groups interviews with 64 New Zealand lone mothers receiving welfare in order to consider how participants made sense of their interactions with the national welfare provider Work and Income New Zealand. The research illustrates the emotional complexity of the welfare environment. This environment, in which the design and delivery of welfare provokes strong feelings, is steeped in emotion. In this thesis I draw upon recent writing in relation to "affect" to argue that, while negative feeling was the origin of many of the troubles the women in my research experienced in the welfare context, emotion also offered participants a way of responding to these difficulties. Welfare mothers have long been framed by social and historical discourses that constitute them as a "social problem" and a threat to the moral order of this country. In New Zealand these discourses also link ethnicity to welfare dependency, and my analysis pays specific attention to the experiences of Maori and Pasifika women who took part in the research. In this thesis I argue that participants' experiences of welfare receipt were dominated by the negative affect inherent in welfare discourse, and that this had a disciplinary function in the welfare environment. While negative affect shapes this thesis, my analysis also draws attention to other less predictable emotions that formed the "affective practices" (Wetherell, 2012) of research participants as they discussed their experiences of welfare receipt. My interest is in the way that emotion was reconfigured in participants' narratives of these experiences. I argue that attending to affect and emotion can offer a way of understanding its role in the maintenance of dominant welfare discourses, and also a means of exploring possible sites for transformation.

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  • Normalized naive set theory.

    Istre, Erik (2017)

    Doctoral thesis
    University of Canterbury Library

    The broad goal of this thesis is the realization of a mathematically useful formal theory that contains a truth predicate, or as it's called in the literature, a "naive theory". To realize this goal, we explore the prospects for a naive set theory which can define a truth predicate. We first consider some of the promising developments in naive set theories using various non-classical logics that have come before. We look at two classes of non-classical logics: weak relevant logics [58, 59] and light linear logics [52]. Both of these have been used in the development of naive set theories. We review the naive set theories using these logics then discuss the strengths and weaknesses of these approaches. We then turn to the primary contribution of this thesis: the development of a robust naive set theory by accepting only normalized proofs, an idea first proposed by logician Dag Prawitz [25, 39]. It is demonstrated that this theory meets our need of logical strength in a system, while possessing more expressiveness in a foundational system than has come before. All of Heyting Arithmetic is recovered in this theory using a type-theoretic translation of the proof theory and other unique features of the theory are discussed and explored. It is further asserted that this theory is in fact the best case scenario for realizing informal proof in a formal system.

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  • Phase ordering dynamics in a ferromagnetic spin-1 Bose-Einstein condensate

    Williamson, Lewis Alexander (2017)

    Doctoral thesis
    University of Otago

    Spinor Bose-Einstein condensates exhibit both superfluid and magnetic order, and accommodate phases with rich symmetry properties and topological defects. Transitions between these phases can be induced by tuning external fields. In this thesis we explore the dynamics of order formation in a quasi-2D spin-1 ferromagnetic condensate following a quench from an unmagnetised phase to one of three ferromagnetic phases. The ferromagnetic phases exhibit distinct symmetry properties (easy-plane, easy-axis or isotropic) and support distinct topological defects. In each phase we observe scale invariant ordering and identify the relevant topological defect affecting the order parameter growth. We find that each phase is characterised by a distinct dynamic critical exponent. In the easy-plane phase we identify a persistent turbulent cascade that affects spin ordering long after all topological defects have annihilated. In addition to our exploration of phase ordering dynamics, we study a microscopic model of spin vortex dynamics in the easy-plane phase. Our work provides a comprehensive theoretical study of phase ordering in a conservative system, provides a thorough foundation for studies of phase ordering in antiferromagnetic and higher spin condensates, and offers prospects for further research into fundamental questions regarding the ordering properties of spin systems. Our work is pertinent to current experiments, which have explored the initial stages of phase ordering in both ferromagnetic and antiferromagnetic spin-1 condensates.

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  • Third molar surgery outcomes: a comparison between intravenous sedation and general anaesthesia

    Ong, Soo-Wee (2017)

    Doctoral thesis
    University of Otago

    Objective. To compare intravenous (IV) sedation and general anaesthesia (GA) for third molar surgery in terms of patient anxiety, satisfaction, choice and, oral-health-related quality-of-life (OHRQoL). Study Design. A quasi-experimental design was used, with a clinical convenience sample of patients requiring the removal of two mandibular third molar teeth. Each participant was consulted by an oral and maxillofacial surgeon or one of their surgical trainees, and they were given a free choice between IV sedation and GA for their operation. Participants completed a questionnaire before surgery and again 10-14 days afterwards. Data collected before surgery included baseline sociodemographic characteristics, OHRQoL, anxiety, aspects of personality (positive and negative emotionality) and history of pain. Data collected after surgery included the severity of pain, time taken for recovery, OHRQoL, anxiety, and satisfaction with the surgery. Results. Of the 142 patients, 73 (51.4%) chose to have the operation under IV sedation and 69 (49.4%) underwent GA. Patients opting for GA scored more highly at baseline on negative affectivity and dental anxiety. After surgery, they reported taking more days off before returning to normal activities, as well as a higher incidence of sore throat and nausea. Conclusion. Patients with negative affectivity and higher anxiety opt for their operation to be carried out under GA but this results in more post-operative side-effects and days off.

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  • Dietary patterns, physical fitness, and markers of cardiovascular health in 9-11 year-old Dunedin children

    Saeedi, Pouya (2017)

    Doctoral thesis
    University of Otago

    Chronic diseases such as cancer, diabetes, and cardiovascular diseases (CVD) are the main health concerns of the 21st century, with CVD as the number one cause of mortality in New Zealand and worldwide. Although CVD hard endpoints such as stroke or heart attacks do not usually occur in children, there is evidence that the manifestation of CVD risk factors begins in childhood, preceding clinical complications of CVD in adulthood. Several factors including biological, environmental, and behavioural factors are associated with the development and advancement of CVD complications. Of these, dietary intake is a modifiable risk factor that has been shown to make a substantial contribution to the risk of death from CVD. Health professionals have long recognised the importance of diets high in fruits and vegetables, wholegrain/high fibre bread and cereals, and limited intakes of sugar and sugar-sweetened beverages in reducing the risk of CVD in adults. However, there is a lack of research in the paediatric population. Thus, the aim of this thesis was to determine associations between dietary intake, particularly dietary patterns as a more global approach of assessing dietary intake and markers of cardiovascular health in 9-11 year-old children in Dunedin, New Zealand. The study was conducted in two phases. In the first phase, a short (28-item) non-quantitative food frequency questionnaire (FFQ) was developed and assessed for its reproducibility and relative validity. Fifty children (mean age±SD: 9.40±0.49 years old) from three Dunedin primary schools completed the FFQ twice, as well as a four-day estimated food diary (4DEFD) over a two-week period. Intraclass correlation coefficients (ICC) and Spearman’s correlation coefficients (SCC) were used to determine the reproducibility and relative validity of the FFQ, respectively. More than half of the food items/groups (52.2%) had an ICC ≥0.50. In relative validity analyses, 70% of food items/groups had a SCC ≥0.30. This FFQ has been used to rank children according to the frequency of consumption of specified food items/groups. The low respondent burden and relative simplicity of the FFQ make it suitable for use in large cohort studies in New Zealand children with similar characteristics. The second phase of the thesis used data from the ‘Physical activity, Exercise, Diet, And Lifestyle Study’ (PEDALS), conducted in 17 primary schools in Dunedin. Of the children who took part in PEDALS, the mean age±SD was 9.72±0.68 years old, 76% were of normal weight, 80% met the guidelines of 60 minutes of daily moderate-vigorous physical activity, and 99% were categorised as fit based on the FITNESSGRAM standards. The first objective of phase II was to identify dietary patterns using principal component analysis (PCA), using the FFQ validated in phase I. Two dietary patterns, namely ‘Snacks’ and ‘Fruit & Vegetables’ were identified. The mean ‘Snacks’ and ‘Fruit & Vegetables’ scores were -0.068±1.98 and -0.005±1.83, respectively. The two identified dietary patterns in PEDALS were similar to commonly identified dietary patterns in both international and national studies. The second objective of phase II was to determine associations between the two identified dietary patterns and components of physical fitness (i.e., cardiorespiratory fitness and handgrip strength). Cardiorespiratory fitness was measured as mean relative V ̇O2max obtained from a 20-metre shuttle run test (20msrt). A digital hand dynamometer was used to measure handgrip strength of both the dominant and non-dominant hands. Complete data was available for 398 participants. Mixed effects linear regression models with robust standard errors and school as a random effect were employed to assess relationships between dietary patterns and components of physical fitness. Mean relative V ̇O2max was 48.7±4.75 ml/kg/min. Handgrip strength of the dominant and non-dominant hand was 15.2±3.29 and 14.4±3.17 kg, respectively. There were no significant associations between the dietary pattern scores and cardiorespiratory fitness. However, fat mass index (FMI) was independently associated with cardiorespiratory fitness. Excess body fat is associated with poorer performance and consequently lower estimated V ̇O2max (ml/kg/min). Furthermore, PEDALS did not find clinically meaningful associations between dietary patterns and handgrip strength of the dominant or non-dominant hand, while sex and fat-free mass index were independent determinants of handgrip strength. Considering the important impact of muscular strength on current and future health status, sex-specific exercise training to improve children’s fat-free mass and muscular strength from as young as 9 years old should be promoted. The third objective of phase II was to investigate relationships between dietary patterns and indices of arterial stiffness (i.e., augmentation index (AIx) and pulse wave velocity (PWV)). Indices of arterial stiffness were assessed using the XCEL system. Data for AIx and PWV analyses were available for 337 and 389 participants, respectively. Mixed effects linear regression models were used to assess associations between dietary patterns and indices of arterial stiffness. Mean AIx and PWV were -2.14±14.1% and 5.78±0.79 m/s, respectively. There were no clinically significant relationships between the dietary pattern scores and AIx and PWV. Arterial stiffness is one of the earliest detectable measures of vascular damage and can be seen in the first decade of life. Although evidence has shown that obesity can accelerate the age-associated arterial stiffening process, the majority (76%) of PEDALS children were normal weight, which may explain the lack of an association. Overall, there were no significant associations between dietary patterns and markers of cardiovascular health in children who took part in PEDALS. The majority of the PEDALS population had a healthy weight status, were of New Zealand European ethnicity, and from families of middle/high socio-economic status. Further research is suggested in a cohort of 9-11 year-old children from families of low socio-economic status and minority ethnic groups such as Māori and Pacific children, using the established methodology of PEDALS. Comparison of the results from PEDALS with a similar study on a group of children with different socio-demographic characteristics would be useful to inform policy and provide further insights on the importance of designing appropriate prevention strategies in both the general and high-risk paediatric populations.

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  • A novel keratin-chitosan-tricalcium phosphate biocomposite as a potential scaffold for regenerative endodontics : an in vitro study

    Ramawarrier, Arunjith (2017)

    Doctoral thesis
    University of Otago

    The present study is the ‘first look’ at a novel biocomposite which may be used as a 3D implantable intracanal scaffold for regenerating dental pulp and periapical tissues. The main ingredient of the biocomposite was low molecular weight keratin protein extracted from sheep wool. Merino sheep wool offers a grand storehouse of keratin proteins which can extracted by many methods. This study used a novel chemical-free method using high temperature and pressure. The extracted proteins were of low molecular weight (3.5-15 kDa) and was water soluble. These proteins were used for the fabrication of the biocomposite along with other ingredients namely chitosan, tricalcium phosphate,barium sulphate and glycerol. This is, perhaps the first study that has explored the use of low molecular weight keratin in biomedical applications. Other constituents of the biocomposite were selected in order to provide specific properties to the composite. Keratin-chitosan formed a mechanically stable homogenous matrix. Chitosan also imparted an antimicrobial potential to the scaffold. Tricalcium phosphate acted as the filler and also a supplier of calcium ions. Barium sulphate provided radiopacity to the scaffold while glycerol was the plasticizer. The scaffold demonstrated many key characteristics relevant to tissue regeneration applications such as adequate porosity and degradation, as well as to endodontic applications such as moderate swelling and radiopacity. Assessment of cytocompatibility yielded promising results. The scaffold promoted proliferation of MDPC 23 (odontoblast like cells) and OCCM 30 cells (cementoblast like cells). The cells were able to grow and achieve functional differentiation when cultured after exposure to scaffold extracts as evidenced by ALP assay which detected elevated ALP levels in culture. AR-S staining detected calcium deposits which further confirmed cell differentiation. Furthermore, immunocytochemical analysis revealed expression of DSPP by MDPC 23 cells which was indicative of odontogenic differentiation. These cell reactions demonstrated the regenerative potential of the biocomposite scaffold. The population density of viable stem cells and their successful differentiation is an absolute prerequisite for successful regenerative pulp therapy, so is the effective disinfection of the root canal system. The antimicrobial potential of the scaffold was tested against S.mutans which was a representative organism for primary infection and E faecalis which represented secondary or re-infection of the root canal system. The scaffold was able to successfully inhibit growth of both the species. This potent antibacterial action of the scaffold eliminated the need for using highly potent antibiotics and other antimicrobials detrimental to host cell survival during endodontic regenerative procedures.

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  • Lymph nodes as a pre-metastatic niche for oral squamous cell carcinoma

    Al Kharusi, Adil (2017)

    Doctoral thesis
    University of Otago

    Background Pre-metastatic niche (PMN) is a new concept in the process of metastasis defined as tumour microenvironment at the future metastatic site which is established by the tumour as a preparation before the arrival of the disseminated tumour cells. Certain cells and cytokines have been reported to be a key factor in building these niches. To date, there is no single study that has investigated the PMN in the oral squamous carcinoma (OSCC). My hypothesis is that IL17, IL22, IL23 and STAT3 play part in the formation of PMN of metastatic OSCC. Aim: To compare the expression of STAT3 and cytokines (IL22, IL23 and IL17) between positive and negative lymph nodes from OSCC. Methods: A total of 36 formalin fixed paraffin embedded (FFPE) tissue specimens were obtained from the Malaysian Oral Cancer Database & Tissue Bank System (MOCDTBS). Sample were divided into two groups. Positive lymph nodes were those with histological evidence of metastatic OSCC while negative nodes were those with no sign of metastasis. Th expression of IL17, IL22, IL23 and STAT3 was investigated using immunohistochemistry (IHC). Gene expression was done using Real time polymerase chain reaction (RT-PCR) to validate the results. Image J was used to count the number of positively staining cells. SPSS was used to analyze the data. Results: IHC results shows that the expression of IL22, IL23 and STAT3 was significantly higher in the negative lymph nodes when compared with the positive group which proof our hypothesis. However, the difference in gene expression was not significant. Conclusion: My results suggest that negative lymph nodes can be a PMN for the OSCC. In addition, IL22, IL23 and STAT3 can be responsible at least partially for the formation of this PMN.

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  • A study of Christology from a tribal perspective: with special reference to Mizoram, northeast India

    Lalpekhlua, L. H. (2005)

    Doctoral thesis
    The University of Auckland Library

    This thesis seeks to interpret Christology from the perspective of tribal people in Mizoram, northeast India, with an objective to help them and their churches to understand Jesus Christ in a way meaningful to them. In this study, historical and socio-theological analysis is used to show that Christology and culture are always related, and that different Christologies have been developed in different cultural contexts. This analysis in turn helps identify the issues that must be addressed in the construction of a contextual Christology for Mizoram context. In this study, Mizo culture and experience are taken into account as essential theological source. The first chapter discusses the need for a contextual Christology and examines the basic issues and methodological approaches surrounding the construction of contextual Christology. In the second chapter, the context of tribal people in Mizoram is analysed. Among the major issues that must be addressed in Christological construction, the thesis identifies the growing disparity between rich and poor within the state and the socio-economic alienation of Mizos from mainland India. The third chapter surveys the Christological tradition in Mizoram from its beginning to the present. It finds that the Christological heritage in Mizoram is largely irrelevant to Mizo people because of its uncritical application of Western theology to this very different historical and cultural context. The idea of Christ introduced into Mizoram is basically individualistic, otherworldly and dualistic. Neither missionaries nor native church leaders have taken the local culture seriously into account in doing Christology. The fourth chapter attempts to recover some major liberating cultural traditions of the Mizos as sources for Christology, including their concepts of pasaltha, humanity, land, God and spiritual beings, and life after death. The study reveals that, despite the Western overlay, there is a significant continuity and influence of traditional culture in Mizo Christianity. On the basis of these findings, the fifth chapter seeks to reinterpret the significance of Jesus Christ in the Mizoram context, using a Mizo conceptual framework. It argues that the idea of the pasaltha incorporates much of the New Testament portrait of the person and work of Christ, Jesus' self-giving life and ministry, incarnation, suffering and death on the cross, can all be seen as manifesting the principle of tlawmngaihna, which is an essential characteristic of the pasaltha. Jesus' resurrection and exaltation can be seen as God's response to Jesus' person and work precisely as pasaltha-tlawmngai. Similarly, the kingdom of God, which defined and summed up Jesus' message and mission, can be perceived in the Mizoram context as exhibiting the qualities of a communitarian society.

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  • "The English of this wildernesse:" Aspects of early New England???s literary inheritance, as illustrated by the works of Anne Bradstreet and Edward Taylor

    Waller, Jennifer Robyn (1974)

    Doctoral thesis
    The University of Auckland Library

    "'The English of this wildernesse': aspects of early New England's literary inheritance, as illustrated by the works of Anne Bradstreet and Edward Taylor." Since the late 1920's, the literature of early New England has been increasingly studied in the context of the development of American history, literature, and mythology. Without denying the usefulness of such a context, I want to redress the balance by setting selected aspects of two writers in particular, Anne Bradstreet and Edward Taylor, in the context of their English origins, and to study them specifically as English provincial writers who exemplify the important phenomenon of cultural lag in a community distant from but crucially attached to a changing metropolitan culture. Part of the originality of my approach is the new look I give to the implications of colonial and provincial literature. Chapter one outlines a detailed historical and critical context for my study. As well, I discuss some of the roots and presuppositions of modern literary scholarship of Early New England, and using T. S. Eliot's distinction between "aesthetic" and "merely historical" criticism, I stress the need for an evaluative context for the early New England poets to complement any discussion of historical perspective. In my second chapter, I tackle crucial and inadequately examined aspects of the influence of Puritanism on New England poetry, concentrating especially on the theological distrust of the imagination and (especially important for Taylor) the literary implications of eucharistic theology. Having developed the major strands of my approach, I then turn to Bradstreet (chapters three to six) and Taylor (chapters seven to nine). Chapter three discusses Anne Bradstreet in the context of Renaissance attitudes to women, in order to show what expectations and possibilities existed for a woman in her position to write poetry. Chapters four and five gradually move from an historical to an evaluative perspective - chapter four to deal with her public poetry, chapter five with her domestic verse and chapter six, her religious poetry. Chapters seven to nine are devoted to selected aspects of Taylor's work. Chapter seven attempts to make a new evaluation of his contribution to the Metaphysical literary tradition; chapter eight explores the implications of his religious beliefs for his poetic practices and especially his constant sense of literary inadequacy. In chapter nine, the crucial question of the relative importance of "historical" and "critical" contexts is again faced as I look at Taylor's poems on the Canticles, not in order to examine his sources, but rather to show the ways in which his poetical imagination responded to and transformed his sources. There is a brief concluding chapter. Throughout the study, I have responded to the great amount of critical and scholarly work done in recent years, and I have therefore concentrated on particular aspects of the topic which, if in no case providing me with totally untouched territory to map, at least have offered the chance of meaningful and original exploration. I also hope that I am offering my explorations within an original and provoking cultural and critical context.

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  • "At school I???ve got a chance...": social reproduction in a New Zealand secondary school

    Jones, Alison, 1955- (1986)

    Doctoral thesis
    The University of Auckland Library

    This study contributes to the contemporary debate within Western radical sociology of education regarding the relationship between the social order and the processes of schooling. It is theoretically well-established in this field that schooling is central to the maintenance of existing social relations of dominance and subordination. Focusing on the commonsense knowledge and classroom practices of two groups of fifth form adolescent girls in an inner-city all-girls Grammar school in New Zealand, the study sets out to analyse and illustrate in concrete detail some of the ideological and pedagogical processes through which schooling contributes to social reproduction. The data and discussion provide insights into the thoughts and everyday school experiences of some middle class Pakeha (European) and working class Pacific Island girls as they seriously attempt to 'get school knowledge' and, thus, the credentials which they believe the school offers the motivated and able. It also shows how teachers unwittingly recruit the active participation of students from 'race' and class groups in pedagogical interactions which often preclude the working class Pacific Island girls from acquiring the school credentials they seek. This process, and that of the school's 'provision' of the middle class Pakeha girls' academic achievement, is then 'misrecognised' by the students as the natural and fair outcome of differential talent and motivation. The theoretical framework of the thesis centres around the major contemporary questions in social theory regarding the agency-structure relationship and how social and cultural life is to be conceptualised as the dialectical product of human agents producing and produced by the social structure within which they exist.

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