644 results for Doctoral, 2010

  • Analysis of fungal inteins

    Bokor, Annika Anna Maria (2010)

    Doctoral thesis
    University of Otago

    xxvi, 298 leaves :col. ill ; 30 cm. Includes bibliographical references. University of Otago department: Biochemistry. "November 1, 2010"

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  • No substantial miscarriage of justice : the history and application of the proviso to Section 385(1) of the Crimes Act 1961

    Downs, Mathew David (2010)

    Doctoral thesis
    University of Otago

    viii, 390 leaves ; 30 cm. Includes bibliographical references. "September 2010. University of Otago department: Law

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  • The rise and development of gangs in New Zealand

    Gilbert, Jarrod (2010)

    Doctoral thesis
    University of Canterbury Library

    Although gang behaviour was in evidence in early colonial New Zealand, the advent of modern gangs can be seen to have occurred in the post World War II period. Since this time, gangs have been heralded as a significant and often severe social problem, particularly as they pertain to issues of law and order. Initially, concerns regarding gangs were focused on their anti social activities and the occasional violent episode, but as many of the gangs became more established this focus broadened to include organised criminal activity. Whether it is images and stories of violent brawls, murders and rapes or, as has been more prominent in recent times, reports of profit driven crime, gang activity receives considerable media attention and thus gangs are afforded a high public profile. Given this profile, it is not surprising that gangs have been an important target for politicians and governments who have introduced various laws in an effort to counter them. Despite the attention paid to them, however, gangs have not been subjected to significant research in this country. Using a wide range of historical documents, ethnographic research and formal interviews, this thesis seeks to examine the rise of gangs in New Zealand and track their evolutionary development. It also focuses on how the community has responded to the issue of gangs, and how, in turn, the gangs have responded to that attention. The findings of this thesis will undoubtedly be surprising to many; despite gangs having a high profile, commonly held ‘knowledge’ of them has most often been learned by sensational media or political rhetoric and is consequently often removed from reality. Informed by many of the understandings gained from the plethora of international research, this thesis attempts to outline and give meaning to a hitherto untold story.

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  • Solution-Phase Synthesis of Nanoparticles and Growth Study

    Cheong, Soshan (2010)

    Doctoral thesis
    Victoria University of Wellington

    This thesis is concerned with solution-phase synthesis of nanoparticles and growth of nanoparticles in solution. A facile synthesis route was developed to produce nanoparticles of iron, iron carbide and ruthenium. In general, the synthesis involved the reaction/decomposition of a metal precursor in solution, in the presence of a stabilising agent, in a closed reaction vessel, under a hydrogen atmosphere. The crystallinity, crystal structure, morphology and chemical composition of the nanoparticles obtained were studied primarily by transmission electron microscopy (TEM), selected area electron diffraction (SAED), powder X-ray diffraction (XRD), and energy dispersive X-ray spectroscopy (EDS). Scanning quantum interference device magnetometry (SQUID) was used to characterise the magnetic properties of iron and iron carbide nanoparticles. In situ synchrotron-based XRD was employed to investigate the growth of platinum nanoparticles of different morphologies. The synthesis of iron and iron carbide nanoparticles was investigated at temperatures 80-160 °C. Syntheses at 130 °C and above produced mainly single-crystal α-Fe nanoparticles, whereas those at lower temperatures yielded products consisting of α-Fe and Fe₃C nanoparticles. Nanoparticles of larger than 10 nm oxidised on the surface leading to core/shell structures, and those of smaller size oxidised completely upon exposure to air. Core/shell nanoparticles of larger than 15 nm were observed to be stable under ambient conditions for at least a year, whereas those smaller in size underwent further oxidation forming core/void/shell structures. The magnetic properties of selected samples were characterised. The core/shell nanoparticles were shown to exhibit ferromagnetic behaviours, and saturation magnetisations were obtained at the range of 100-130 emu g⁻¹. Nanoparticle size and size distribution, and morphology were found to be a result of combined effect of precursor concentration and the relative stabiliser concentration. In general, high-precursor concentration resulted in less controlled reaction and produced large nanoparticle size and size distribution. Under the high-concentration condition, the use of stabilisers in reduced amount then led to a diverse range of morphologies, which include dimer, porous and branched structures. As for the synthesis of ruthenium nanoparticles, reactions of different precursors were investigated at temperatures ranging from room temperature to 140 °C. Highly crystalline ruthenium nanoparticles of different sizes and morphologies were obtained through different experimental conditions. The increase in nanoparticle size was found to be a result of increasing reaction temperature and/or decreasing stabiliser to ruthenium ratio. This trend was observed to be independent of the type of stabilisers and precursors used. The use of stabilisers with different binding characteristics has facilitated the formation of non-spherical nanoparticles; these include rod-like structures with high aspect ratios (of up to 12), hexagonal and truncated triangular plate-like structures, and tripods. The growth of faceted and branched structures of platinum nanoparticles was investigated by employing in situ XRD techniques. TEM was used to examine the intermediate structures. The two different morphologies were previously shown to be governed by precursor concentration. It was found that the growth in the low-concentration reaction was characteristic of a thermodynamically controlled regime, whereas that in the high-concentration reaction occurred at much greater rates under a kinetically controlled regime. Based on the observations obtained, different growth mechanisms were proposed and discussed. The former involved an oriented attachment mechanism, while the latter, a novel mechanism involving selective growth and etching processes. The results are followed by an overall discussion comparing and contrasting the various syntheses involved, and relating the results of syntheses to those of the growth studies.

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  • Chinese Immigrant Children in New Zealand Early Childhood Centres

    Guo, Karen Liang (2010)

    Doctoral thesis
    Victoria University of Wellington

    This research investigated the learning experiences of Chinese immigrant children in New Zealand early childhood centres with the aim of describing educational implications for early childhood professionals. A qualitative research approach was adopted using a multiple case study design. Eight Chinese immigrant children aged three to five years, their parents and their teachers participated in the study; the children were enrolled in six early childhood centres in a large urban area. Procedures of data gathering included child observations, and child, parent and teacher interviews. Data were analysed from phenomenological and sociocultural perspectives. The children's learning experiences, particularly languages and interpersonal relationships, were discussed from the perspectives of sociocultural theories. The concept of a learning community contributed to the analysis which was also influenced by the notions of cultural diversity and multiculturalism. A major theme of this research was the value of the culture of Chinese immigrant families to mediate the learning experiences of Chinese immigrant children in New Zealand early childhood centres. Familiar cultural tools and mediators provided important support for the children who were able to access them in their centres. The children's intention to drive their own learning experiences was also a salient feature. Evidence was documented that illustrated how learning and development were mediated by fulfilment of feelings of belonging, as well as the children's commitment to cross cultural boundaries. The Chinese immigrant children were active drivers of their own learning and capably negotiated and created the relationships between their family culture and that of their early childhood centre. Specific strategies they adopted to construct their own learning experiences were found to be significant in explaining the emergence of hybrid cultural tools which mediated the children's evolving development of appropriate repertoires of practice in their early childhood centres. This thesis contributes to the body of sociocultural research via the examination of children's creation of intercultural learning possibilities. It provides early childhood teachers with insights regarding how to enhance pedagogical policies, values and practices to more closely align with sociocultural frameworks, concepts of learning communities and cultural diversity. It is important that diverse cultural relations are appropriately established in the early childhood centres so that immigrant children can move between different cultures in order to generate a useful intercultural way of being for themselves.

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  • Tobacco smoke extract modulates activity and expression of monoamine oxidase and μ opioid receptor in cultured human neuroblastoma cells

    Lewis, Amy Jane (2010)

    Doctoral thesis
    Victoria University of Wellington

    Tobacco addiction is a major public health concern and is responsible for approximately five million deaths globally each year. Although most current smokers express a desire to quit, few are successful in their attempts. Nicotine is the primary neurobiologically active component in tobacco smoke and acts through the nicotinic acetylcholine receptor (nAChR) to sustain addiction. However, nicotine replacement therapies have proven to be remarkably ineffective at helping smokers quit. This indicates that nicotine alone cannot fully account for the intense and enduring nature of tobacco addiction. Previous research has provided strong evidence that monoamine oxidase (MAO) enzymes and the endogenous opioid system may also play a role in tobacco dependence. The present study compared and contrasted the influence of nicotine and the non-nicotine components of tobacco smoke on the enzyme activity of MAO-A and MAO-B. Gene expression of MAO and the mu opioid receptor (MOR) in SH-SY5Y human neuroblastoma and U-118 MG glioma cell lines was also investigated. Using a kynuramine-based enzymatic assay adapted and optimised for this study, the MAO inhibitory activity of tobacco-based samples were tested, including total particulate matter (TPM) extracts from a range of New Zealand tobacco products, Quest(R) nicotine-free cigarettes, and fluid from the RUYAN(R) Electronic cigarette. TPM from both standard tobacco and Quest(R) significantly inhibited MAO-A and MAO-B activity in vitro and in cultured cells. Differences between the types and brands of tobacco products were observed. TPM derived from loose-leaf tobacco inhibited MAO enzymes more potently than samples from manufactured cigarettes. This difference was attributed to a significantly higher tar:nicotine ratio in loose-leaf tobacco. Standard TPM and Quest(R) TPM also inhibited total MAO activity in SH-SY5Y cells treated for 24 hours; whereas the weak activity in U-118 MG remained unchanged. However, MAO activity was highly dependent on the cell culture conditions, with activity increasing in SH-SY5Y cells when treated with a 5-day exposure regimen. This finding was unique to the present study. The gene expression of MAO-A, MAO-B, and MOR was examined using a qRT-PCR assay. All three genes were significantly up-regulated by standard and denicotinized TPM extracts after a 5-day treatment regimen. This finding was correlated with an increase in protein abundance for MOR, but not MAO-A or MAO-B, as assayed by Western blot. Up-regulation of MAO and MOR gene expression was abolished when cells were treated with TPM extracts in conjunction with the nAChR antagonist mecamylamine, suggesting that up-regulation of MAO and MOR genes was dependent, at least in part, on nAChR signalling. Both standard TPM and TPM from denicotinized Quest(R) cigarettes induced inhibition of MAO and up-regulation of MAO and MOR gene expression. This demonstrates that non-nicotine compounds within tobacco smoke can significantly influence the behaviour of cultured neuronal cells. Further research is required to fully elucidate the mechanisms behind the MAO and MOR gene response, and a better understanding of these mechanisms may provide a framework for the development of novel smoking cessation therapies.

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  • Impact of Macro and Micro Governance Structures on Earnings Management

    Houqe, Muhammad Nurul (2010)

    Doctoral thesis
    Victoria University of Wellington

    This study examines the macro and micro level determinants of the quality of reported earnings. The prior literature suggests that both micro and macro variables impact on discretionary accruals choice in managing earnings. However, most of the studies on earnings management have been single country studies that have focussed only on micro variables as all firms within the samples examined have been subject to the same interplay of macro economic, legal, cultural and institutional frameworks. This study addresses this gap in the literature by using a sample of 156,906 firm year observations from 63 countries over the period 1998-2007 to examine the role of thirteen micro and macro variables in determining earnings quality. The macro variables studied include legal enforcement, political system, and control of corruption, culture and adoption of IFRS. Earnings management is estimated using the modified Jones model (Dechow et al. 1995) in a cross section (DeFond and Jiambalvo 1994; Francis et al. 1998). The results of the study indicate that macro and micro level variables have a strong impact on earnings management behaviour and thus earnings quality. The limits imposed by a country's legal, cultural and institutional setting on managerial discretionary accruals choices, strongly impact the quality of reported earnings. Future research on earnings management should therefore control both micro and macro level variables.

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  • Gravidographics: A Health Lifestyle Segmentation of Pregnant Women in Transition to First Time Motherhood

    Krisjanous, Jayne (2010)

    Doctoral thesis
    Victoria University of Wellington

    The purpose of this thesis is to contribute a new health psychographic/ lifestyle segmentation of pregnant women in New Zealand who are in transition to first time motherhood. It provides a better understanding of the make up of the market and the way it aggregates into health lifestyle segments. By using a wide selection of pre-existing and pregnancy related health and attitude dimensions, it complements existing understanding and classifications of pregnancy health lifestyle. First, the study richly describes pregnancy health behaviour within a representative cohort of pregnant women in a transitional lifestyle using a holistic framework. It takes into account lifestyle as made up of a combination of factors and underlying motivations. Furthermore, it establishes the application of 'lifestyle' as it is used in marketing as legitimate for the study of a transitional health lifestyle. The research is cross disciplinary, and for that reason, integrates two perhaps seemingly disparate (marketing and health) understandings of lifestyle, using a somewhat novel approach. It is inclusive of high risk pregnant women and a much less oft studied group, normal, healthy or low risk women. Second, a key component of this study is the seminal development of a segmentation typology that classifies women's health in pregnancy through a situation specific psychographic approach. This typology has been termed 'Gravidographics', and identifies segments of pregnant women, who have distinct or unique identifiers in regard to their pregnancy health lifestyle. This knowledge will be useful for health behaviour change through social marketing and also the design and targeting of products and services to specific groups of pregnant consumers. A third focus of the study is the examination of health lifestyle within the concept of life stage transition. As pregnancy marks the transit into a new life stage, there are many adaptations that need to be made, and several underlying factors influence the way such a journey is approached and achieved. The study is exploratory and the conceptual framework, derived predominantly from the marketing and health literature, guides the study and informs development of the data collection tools. Eight main research questions are explored. The study uses a survey design and is cross sectional, with quantitative enquiry the dominant logic. A survey using a self administered health psychographic questionnaire was distributed by Lead Maternity Carers to pregnant women in their care. A sample of 478 women was obtained for this stage of the study. Quantitative analysis was undertaken through descriptive statistics and bi-variate analyses. Secondly, two step clustering was undertaken to develop pregnancy health lifestyle clusters. Four health lifestyle segments were identified. These segments were then profiled against additional variables and data that led to rich descriptions of each segment. Several managerial recommendations are made that will assist in the delivery and positioning of maternity health goods and services particularly in regard to healthcare marketing and segmentation. Secondly, recommendations for future marketing communication strategies targeting pregnant women are made. Through this work, the study's ultimate aim; making an academic contribution to knowledge that will lead to improved health outcomes for mother and baby, has been achieved.

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  • eCommerce Website Evaluation framework: An Owner's Perspective

    Ghandour, Ahmad (2010)

    Doctoral thesis
    University of Otago

    In New Zealand, many businesses are investing in setting up their websites to sell goods and services as online trading becomes more popular. This action has caused disillusionment for some companies as it is difficult to clearly articulate the real benefits which could be derived from being online. This is may be due to the lack of an evaluation framework that enables owners to diagnose the performance of their eCommerce website. Current evaluative approaches presented in the literature are based on the users’ experience and fail to address the owner’s concerns. The research presented here is focussed on how to evaluate eCommerce websites based on the owner’s experience point of view. In order to be able to evaluate eCommerce websites, this study: (a) proposed a conceptual framework for eCommerce website evaluation, (b) developed measurement scales for the conceptual framework, (c) collected data based on owners’ perceptions (experience) with their websites, (d) tested the scale in businesses implementing eCommerce websites, and (e) investigated the relationship between the dimensions in the conceptual framework. The proposed research model is based on the current conceptualisation of Information Systems (IS) success models which suggest that success is a multidimensional construct. However, the customer experience is the dominant view taken in these success models. In the proposed model, and in order to address the concern of businesses setting up a website, evaluation is considered from the owner point of view. That is, a process model which links website offer to its payoffs through usage. Extra theoretical perspectives were necessary to account for the shift to the owner’s experience. Since the evaluation is based on the owner’s process understanding of creating a website, the owner satisfaction is included in the process as a contextual variance. This will enable factors in the evaluation model to be clearly linked in causal relationships that lead to owner satisfaction as an ultimate favourable result. Data was collected from 225 New Zealand businesses that have an eCommerce website through an online survey. The research model was tested using the two-step approach of Structural Equation Modeling (SEM) where the structural model and measurement model were separately analysed. A set of measurement models was used to determine indicators that capture each construct and a structural model was used to determine the relationships between concepts. Each measurement model was tested in isolation, then factors forming the endogenous variables, followed by factors forming the exogenous variables were each separately tested, and finally a collective network was determined and tested. The key findings of this research showed that there are four factors that explain the change of performance in the website. These factors are: website offer, usage, financial returns, and owner satisfaction. The study concluded that websites could be evaluated along those four factors the effectiveness of which could be monitored along their measurement scales. It is also premised on the same variable that these factors function in a serial manner and the ultimate measure of effectiveness is owner satisfaction. The study also concluded that these factors explain the success of a website; each factor is necessary but not sufficient on its own to explain the success of a website.

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  • Marginally grounded: Camping ground residence in New Zealand

    Severinsen, Christina Anne (2010)

    Doctoral thesis
    University of Otago

    This study describes the nature of the experiences of camping ground residents in relation to their health, and within the context of individual, local and national spheres. It situates camping ground residence as a particular form of housing, and contests public understandings of camping grounds as only summer holiday destinations. Researchers from a range of disciplines continue to make advances in understanding the links between housing and health and extending our knowledge of the relationship. Housing as a health issue is multi- dimensional and complex; it affects individuals and how they interact with their communities and wider society. This thesis views housing in broad terms, taking into account the many influences that shape people’s experiences of their housing. While adequate housing has been identified as a key social determinant of health, and is a major policy goal in New Zealand, there has been little research focused on temporary accommodation. Camping grounds as a form of housing have not been previously discussed in the New Zealand literature. This thesis presents a narrative analysis of in-depth interviews carried out with 22 camping ground residents and 20 community key informants, in order to present a comprehensive insight into the dynamics of life in camping grounds. This thesis examines camping ground residence through a framework of the socio-spatial nature of housing, and through concepts of place, community and housing pathways. The research highlights the broader socio-political context in which New Zealand camping grounds operate, including the legal and regulatory frameworks, public representations, and definitions of homelessness and healthy housing. The politicisation and problematisation of camping ground residence illustrates the tensions surrounding the provision of housing in camping grounds, which is related to the marginalisation and social exclusion of those who live in camping grounds. This research explores camping ground residence as both positive and detrimental to the health of residents, through the shaping of residents’ opportunities and access to housing resources and community. The social exclusion and vulnerability of some residents, exacerbated by situations of poor quality housing and housing insecurity, is presented alongside other aspects of camping ground residence, such as opportunities to develop social networks and place attachment, which may mediate some of the effects of poor housing and social exclusion. The findings here offer an understanding of camping ground residence in New Zealand and conceptualise residents’ movements in, through and out of camping grounds. Narrative analysis enabled a comprehensive analysis of the experiences of those living in camping grounds, and facilitated reflection on the many layers of context and experience that shape residents’ housing and health. The thesis concludes by emphasising camping ground residence as contested and complex, and camping grounds as sites of the politics of place.

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  • Factors mediating successful oral vaccination with lipid-encapsulated Mycobacterium bovis BCG

    Czepluch, Wenzel (2010)

    Doctoral thesis
    University of Otago

    During the course of this thesis factors mediating successful oral vaccination with lipidencapsulated Mycobacterium bovis BCG were examined. Mice were fed 2x10E07 CFU BCG encapsulated into a lipid matrix to prevent destruction by the gastrointestinal tract and to allow passage through the gut epithelia. In order to trace the vaccine following oral vaccination, mice were sacrificed at various time points ranging from 6 hours to 8 weeks post vaccination, and macerated lymphatic and non-lymphatic organs plated on solid agar. Initially, BCG was distributed widely in lymphatic and non-lymphatic organs, however, BCG was cleared quickly from most organs and formed small populations of less than 500 CFU/mouse in the mesenteric and cervical lymph nodes, as well as the Peyer’s patches 8 weeks post vaccination. Immuno-histochemistry and confocal microscopy, showed that BCG was absent from the follicles, but instead resided in the T cell containing intra-follicular areas. Very rarely BCG was associated with small CD11b+ cells that did not resemble typical macrophages and lacked peroxidase activity. Instead the majority of BCG could be found forming extracellular groups of 1-4 rods. This was confirmed using cell sorting of leukocytes isolated from alimentary tract lymphatics of orally vaccinated mice and only showed a minority of BCG to be associated with CD11c+ cells. Therefore, BCG is absent from typical antigen presenting cells, but instead might reside in CD11c+CD11b+ myeloid DC. Additionally, Ziehl-Neelsen staining revealed groups of intracellular coccoid forms of BCG. These were located toward the subcapsular space of draining lymph nodes where they were associated with sub-capsular macrophages. Interestingly, cocci proved to be non-platable using solid agar but instead required resuscitation in liquid media and therefore might resemble a form of dormancy. The presence of extracellular rods and intracellular cocci in on-professional antigen presenting cells might highlight the importance of secreted factors as an antigen source promoting successful activation of the immune system. Following oral vaccination, IFN-γ producing cells almost exclusively resided in the spleen. In order to characterize these cells, splenocytes of orally vaccinated mice were isolated 6 weeks post vaccination on the basis of surface marker expression using fluorescence activated cell sorting (FACS). Antigen-specific release of IFN-γ was monitored using ELISA and ELISpot assays and IFN-γ producing T cells were characterized as T effector memory cells expressing CD44, but not CD62L and lacked the expression of mucosal homing markers such as CD103 or α4β7. In addition, Lincoplex assays revealed the production of IL-17 by splenocytes. These did not express CD4+ but rather the γδ T cell eceptor. Together these results show that antigen reservoirs of BCG present in the draining lymphatics contain small numbers of typical filamentous BCG. A larger population of coccoid forms leaves open the possibility that coccoid forms are a major source of antigen for the stimulation of T cells. Although typical CD11c+ APC isolated from the lymphatic tissue of immunized mice did not appear capable of stimulating, T cells responses were nevertheless effectively induced by oral vaccination and shown to be IFN-γ producing TEM residing in the spleen but lacking expression of mucosal homing markers.

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  • A Braided River: New Zealand Baptists and Public Issues 1882-2000

    Tucker, John Harvey (2010)

    Doctoral thesis
    University of Otago

    1 v. (various paging) :ill. (some col.), maps (some col., some folded) ; 30 cm. Includes bibliographical references. University of Otago department: Theology and Religion.

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  • Acoustically derived growth rates and three-dimensional localisation of sperm whales (Physeter macrocephalus) in Kaikoura, New Zealand

    Miller, Brian Seth (2010)

    Doctoral thesis
    University of Otago

    Kaikoura, New Zealand is one of a few places worldwide where sperm whales can be found near-shore year-round. However, diving depths and underwater movements of the sperm whales here have remained largely a mystery due to technological limitations, lengthy dive durations, and deep bathymetry typical of dive locations. The overall goal of this research was to quantify sperm whale acoustic and diving behaviour in Kaikoura, in order to better understand the ecology of this globally distributed species. Multihydrophone recordings and emerging signal processing techniques were used to obtain information on whale growth, vocal behaviour, underwater movements, and foraging habits. Software written to compute acoustic size estimates formed the basis of a new nonlethal method for measuring growth of resident sperm whales. Growth rates were measured for 32 whales that had been recorded repeatedly between 1991 and 2009. All whales with multiple recordings more than six months apart showed an increase in size, and the largest changes were present in whales recorded over longer timespans. To investigate underwater movements and vocal behaviour, a passive sonar array was designed and built for tracking diving sperm whales in three dimensions. The system consisted of four free-floating buoys, each with a hydrophone, depth sensor, built-in recorder, and GPS, and one vertical stereo hydrophone array deployed from a 6 m boat. Recordings were synchronised using a GPS timing pulse modulated onto one track of each recorder. Passive acoustic detection and localisation algorithms were developed and applied to recordings to obtain diving profiles. Detection algorithms, which included two different energy detectors both with and without a matched filter, all performed well showing few false positives at low signal-to-noise ratios. Closely spaced hydrophones on the vertical array were used to estimate bearings to individual whales, and these bearings formed tracks that could distinguish a single whale when multiple whales were vocalising. Rhythm analysis was used to match vocalisations among recording platforms, and cross-correlation was used to compute time of arrival differences among matched vocalisations. Sensitivity analysis based on hyperbolic localisation was used to obtain probability distributions for the whale’s 3D location. These localisations were compared to those computed by a particle filter algorithm, isodiachronic sequential bound estimation, which had higher accuracy. Location data consisted of 3D probability clouds, which differ from 2D point-locations typically obtained in animal tracking studies. An analysis method based on a speed-filter and smoothing spline interpolation was used to convert 3D localisation clouds into regularly sampled 3D tracks. While diving, whales in Kaikoura had a mean swimming speed of 1.43 m/s, and, on average, dived to a depth of 432 m. Tracking whales during creak vocalisations revealed that whales foraged throughout the water column from sea surface to sea floor, but 67% of all creaks occurred between depths of 275 - 725 m. Dive characteristics from 78 interpolated 3D tracks from Kaikoura were broadly similar to those computed from one- and two-dimensional tracks of sperm whales studied in other oceans.

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  • Using the Eyes in the Back of our Heads: An Ecological Appraoch to Reducing Unintentional Injury to Young Children in the Home Environment

    Simpson, Jean C (2010)

    Doctoral thesis
    University of Otago

    The rate of unintentional injury among children in New Zealand is not one of which we can be proud. Of children under 15 years, those aged 0-4 years carry the greatest burden and these children are injured at home more often than elsewhere. Measuring mortality, morbidity or controllable hazards, and determining risk factors, have been crucial starting points for developing interventions for child home injury. Some specific causes have been addressed successfully, but many predictable and preventable injuries still occur. From a health promotion perspective, this lack of progress would suggest that preventing injuries to young children at home is not a simple problem. Complexity is no excuse for inactivity, however. Children are vulnerable members of our society and are dependent on the behaviour and actions of others for their safety. It is crucial to identify how to design, develop and deliver initiatives that will bring about the changes needed to reduce child home injury. The use of the behavioural sciences has expanded the knowledge used in injury prevention beyond an epidemiological approach. Behaviour and context affect safety, and both are important elements in child home injury and its prevention. This study took an ecological approach to investigate the contextual and personal influences, and their interactions, of child injury prevention in the home environment. In particular, the influences on parents’ perceptions of the risk of injury to their young child at home, and their responses to that risk, were examined. These questions were explored with the real practitioners of home safety: mothers, and community-based health professionals and community workers who constantly engage with young families. Recognising these practitioners’ experience, observations, and views as legitimate knowledge shifted the focus from that commonly used in seeking to reduce child injury at home. The participants’ narratives offer additional valid and insightful perspectives to the problem. Green and Kreuter’s PRECEDE framework and Bronfenbrenner’s ecological thinking underpinned the study. A constructivist inquiry approach was used with semi-structured, open-ended interviews gathering common and diverse experiences, and observations, from face-to-face parent interviews and family worker focus groups. Analyses identified a set of themes, some of which supported findings from existing literature on influences on parental perceptions of, or responses to, the risk of child injury. Additional themes emerged indicating the influence of ‘upstream’ (from society, policy and systems, and community) and ‘downstream’ (from the personal and immediate environment) factors. The themes indicate that parents’ perceptions and responses are operating in a complex, dynamic environment where factors interact. Analyses on the downstream themes, using Bandura’s Social Cognitive Theory, resulted in key downstream influences being identified as fatigue, and knowledge of the child, of child development, and of safety management. Analyses on the upstream themes, using Rittel and Webber’s “wicked problem” model, found key themes such as lifestyle, understanding and valuing of caring, economics, and the changing nature of family. Recommendations suggest actions, based on the Ottawa Charter for Health Promotion, at both the downstream and upstream levels that would contribute to improving home safety for young children.

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  • Epigenetic Programming and In Vitro Fertilisation

    Oliver, Verity Frances (2010-04-08)

    Doctoral thesis
    University of Otago

    In vitro fertilisation (IVF) potentially provides a profoundly abnormal environment for an embryo. Studies with mice, sheep and cattle have indicated that the culture environment of the embryo can affect the imprinting of genes and the phenotype of the animal. Recent studies have suggested that IVF causes a small but increased risk of epigenetic imprinting aberrations such as Angelman syndrome and Beckwith-Wiedemann syndrome. Our previously published IVF cohort is taller, has higher levels of growth hormones and a better lipid profile than age-matched controls. Mosaicism for the imprinting defect at SNRPN has been observed in Angelman syndrome. We hypothesised that mosaic imprinting defects may be present in phenotypically normal individuals conceived using IVF. DNA samples from peripheral blood were obtained from 66 IVF-conceived children and 69 matched controls. DNA methylation of CpG sites within the Beckwith-Wiedemann syndrome region (H19, KCNQ1OT1 and IGF2) and the Angelman syndrome region (SNRPN) were quantified using methylation-sensitive restriction digest followed by real-time quantitative PCR (MSQ-PCR). Global DNA methylation was also examined by using MSQ-PCR on Satellite 2 repeats. No differences in the percentage of methylation between the IVF and naturally conceived children were observed at H19 (P = 0.75; unpaired t-test), KCNQ1OT1 (P = 0.98), SNRPN (P = 0.33), IGF2 (P = 0.44) or Satellite 2 (P = 0.79). These results were confirmed using bisulfite sequencing. An individual with Prader-Willi syndrome was identified during the recruitment of this cohort. Five Prader-Willi syndrome cases have previously been identified in the IVF population. The underlying cause of Prader-Willi syndrome was identified to be a deletion of the chromosome 15q11-q13 region. This case did not provide evidence that aberrant methylation can occur during IVF. Pyrosequencing technology was used to measure the methylation at multiple CpG sites within H19. No methylation defects were identified at H19 in the IVF group compared to naturally conceived controls. This technology proved to be prone to inaccuracies and was not used for subsequent analyses. Genome-wide methylation analysis was examined using microarray technology and methylated DNA immunoprecipitation (MeDIP). Thirteen candidate differentially methylated genes between the IVF-conceived and control children were identified. Detailed examination of candidate genes using the Sequenom MassARRAY® EpiTYPER® system did not reveal any differential methylation at these genes assessed in the IVF and naturally conceived children. Although anthropomorphic and endocrinological data suggested a phenotypic difference between IVF and naturally conceived children, no differentially methylated genes were identified that could account for these differences. We concluded that low-level imprinting errors are not a common occurrence in children conceived using IVF. Our data also provides reassurance that IVF-associated epigenetic errors are sporadic and rare.

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  • Understanding the Structure of the Bovine Milk Fat Globule and its Membrane by Means of Microscopic Techniques and Model Systems

    Gallier, Sophie Yvette Fabienne Christine (2010)

    Doctoral thesis
    University of Otago

    The bovine milk fat globule membrane (MFGM) is an important, biologically relevant membrane due to its functional and health properties. Its composition has been thoroughly studied but its structure, especially the lateral organization of its components, still remains unclear. The aim of this project was to improve the knowledge about the structure of the bovine milk fat globule and, in particular, its membrane by means of microscopic techniques and model systems. Phospholipids are the backbone of the MFGM structure. Different techniques of phospholipid extraction were carried out on buttermilk powder to determine the technique most reproducible and giving the highest recovery of sphingomyelin. Natural complex mixtures of phospholipids from raw milk, raw cream, homogenized and pasteurized milk, and buttermilk powder were recovered through total lipid extraction following the Folch method and solid-phase extraction using the Bitman method. All mixtures were analyzed using electronspray-ionization tandem mass spectrometry to determine their phospholipid profile and their fatty acid distribution, and also to reveal the effect of milk processing on the phospholipid composition. Confocal-Raman microspectroscopy was used to investigate the lipids of the milk fat globules. A comparison of the fat globule composition between two breeds of cows and between globules of different size was carried out and revealed differences in lipid content and fatty acid distribution. Confocal-Raman microspectroscopy provided information on both the lipid core and the milk fat globule membrane. Milk fat globules from raw milk, raw cream and processed milk and reconstituted buttermilk powder were stained with fluorescent probes and observed with a confocal laser scanning microscope (CLSM). Domains, which are thought to be rich in sphingomyelin and cholesterol, were observed on the surface of the native globules. These domains, also called lipid rafts, are a liquid-ordered, lo, phase coexisting with a liquid-disordered, ld, phase. Phase separation, distribution of glycoproteins and glycolipids and association of milk proteins with the MFGM were determined in all samples. Lipid microdomains, analogous to lipid rafts in cell membranes, were observed at the surface of the globules. Glycoproteins and glycolipids were heterogeneously distributed within the MFGM and located outside of the lipid microdomains. Proteins were found associated in a higher amount with the fat globule membrane after processing the milk. The temperature effect on phase separation was also assessed. Temperature induced a change in the size, shape and number of the lipid microdomains at the surface of the globules. A comparative study with the milk fat globule membrane from mares’ milk revealed similar phase coexistence at the surface of the globules. The observation in situ with non-invasive techniques provides further progress in the understanding of the lateral heterogeneities existing within the MFGM. Over the past few years, increasing attention has been given to the study of the functions and properties of lateral microdomains in biological membranes. However the environmental conditions of the native membrane system, such as temperature and pressure, cannot be readily modified and their effects on the MFGM monitored. Therefore the use of model systems is a very promising tool to investigate the effect of temperature and pressure on this system. The physical behavior of the phospholipid monolayers from each dairy product was investigated with a Langmuir trough mounted on an epifluorescence microscope to probe the impact of milk processing. Phase separation was observed as a function of varying pressure (0mN/m to 60mN/m) and temperature (16, 20, 24 and 27°C). The surface pressure (π)-specific area (A) isotherms showed a similar trend, however the phase coexistence under epifluorescence microscopy revealed different patterns with different phospholipid sources. The surface pressure, the temperature, the phospholipid composition, the degree of saturation and the fatty acid chain length were factors determining the shape and number of the liquid-ordered domains. Atomic force microscopy (AFM) was used as a complementary method to reveal topographic nanometer-size height differences between the liquid-ordered phase and the liquid-disordered phase. To reach a closer model system to mimic the MFGM, an abundant milk protein, β-casein, was added sub-phase to the phospholipid monolayer and the effects on the compression isotherms and the shape of the liquid-ordered domains were followed at different pressures and temperatures for each phospholipid monolayer film. AFM was used to locate the protein within the film as the detection of the protein location was not possible within Langmuir phospholipid-protein films by epifluorescence microscopy. AFM imaging revealed the branching of β-casein molecules, clustering three to four liquid-ordered domains together. Even though the composition of the MFGM is well established, there are still unanswered fundamental questions concerning the structure and dynamics of the MFGM and the existence of rafts within this unique trilayer membrane. The aim of this thesis was to study the native intact and processed MFGM, as well as complementary investigations of model monolayer systems composed of natural complex mixtures of phospholipids present in the MFGM and milk proteins. Model system studies gave critical insights into the role of lipid-lipid and lipid-protein interactions in raft formation and function in the MFGM.

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  • Monitoring Snow Cover and Modelling Catchment Discharge With Remote Sensing in the Upper Waitaki Basin, New Zealand

    Sirguey, Pascal Jean Bruno (2010)

    Doctoral thesis
    University of Otago

    Because New Zealand relies heavily on water for electricity generation, it requires strong and reliable information about its water supplies as well as better knowledge about the processes that affect them. Situated in the Southern Alps, the Waitaki basin is the most important hydro catchment in New Zealand. Three alpine sub-catchments, namely Ohau, Pukaki, and Tekapo, provide most of the discharge to the Waitaki River. In this alpine region a large part of the water resource is temporarily stored as seasonal snow cover. To utilize better the value of water in hydro lakes, improving knowledge of the timing and supply of water from seasonal snow is a priority. It has been long established that satellite remote sensing is a powerful tool to monitor snow cover in remote and inaccessible areas. In New Zealand, this technology has received only scant consideration. In addressing the remote sensing of the seasonal snow cover in the alpine catchments of the Waitaki basin, this thesis aims at filling a considerable void. This is achieved through the implementation of routine monitoring of the snow cover dynamics with the MODerate Imaging Spectro-radiometer (MODIS). Towards this goal, several advanced remote sensing techniques that are novel to MODIS are integrated in a single and operational algorithm. This research demonstrates the desirable performance of an image fusion algorithm. The algorithm enables the mapping of snow with MODIS at 250m spatial resolution instead of the 500m spatial resolution imagery currently available. Furthermore, MODIS images are standardized by means of a physically-based atmospheric and topographic correction (ATOPCOR) approach. Finally, the radiometric normalization of the time series permits the design of a robust spectral unmixing technique. This allows further enhancement of the spatial details of the snow maps through the determination of sub-pixel snow fractions at 250m spatial resolution. Together, the combination of these techniques forms a processing chain, well suited to the mountainous environment, to map snow with the highest possible amount of spatial detail. A careful assessment of the quality of the maps of snow fractions is conducted by means of comparison with high resolution reference snow maps obtained from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The processing of seven years of MODIS observations covering the 2000--2006 hydrological years permitted the creation of a new dataset that depicts the spatial distribution of snow. Based on this dataset, this thesis demonstrates that the current modelling approach of the snowpack by the model SnowSim tends to propagate errors that increase to an important level. Every year by the end of the ablation season SnowSim models nearly a quarter of the total water storage in locations that are free of snow according to observations from MODIS. Finally, the hydrological modelling approach enabled by the Snowmelt Runoff Model (SRM) is revisited. Daily meteorological data (i.e., temperature and precipitation) and the frequent observations of the snowpack provided by MODIS enable the daily discharge to be simulated. Unprecedented performance in the simulation of daily inflows are obtained for the three largest water reservoirs in New Zealand. This sheds new light on the relative contribution of seasonal snowmelt and ice melt to the discharge. In revealing the large daily variability of the snowmelt, new estimates of its contribution to the lake inflows are obtained. Over the study period, snowmelt accounted for 37%, 40%, and 31% of the discharge in the Lakes Ohau, Pukaki, and Tekapo catchments, respectively. Finally, this research documents the severe drought of 2005. It strongly suggests that inflows were largely mitigated by ice melt from glaciers in the Pukaki basin. A contribution of glacier melt much larger than usual is believed to have sustained the discharge to within 17% of the mean annual flow, although precipitation was reduced by 34%. This mitigating factor was less marked in Tekapo and not observed in the Ohau basin, in accordance with the relative proportion of glacierized areas in the catchments. This potentially provides a striking example of the contribution of long term storage to inflows during dry periods.

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  • Tourism and Seismic Risk: perceptions, preparedness and resilience in the zone of the Alpine Fault, Southern Alps, New Zealand.

    Orchiston, Caroline Hamilton (2010)

    Doctoral thesis
    University of Otago

    The islands of New Zealand lie astride two actively deforming tectonic plates, creating a diverse physical landscape with high scenic value, but one which is prone to a range of natural hazards. The Alpine Fault is a 450 km-long fault which defines the position of the plate boundary as it runs the length of the Southern Alps in the South Island. Paleoseismic evidence suggests it is overdue for a significant earthquake of magnitude ~ 7.8 - 8. Coincident with this area of high seismic potential is a burgeoning tourism industry, which, over the past two decades has shown remarkable growth, capitilising on the region’s international reputation for unique nature-based tourism experiences. Visitor activities occur, at times, in relatively remote and hazardous settings, such as National Parks, alpine or coastal areas. Many tourism destinations in the Southern Alps can only be accessed via alpine passes or road ends. This research project adopted three methodological approaches to satisfy two objectives. The first objective of the study investigated the physical outcomes of a large Alpine Fault earthquake on the tourism industry. Modelled isoseismal data for a number of earthquake magnitude scenarios were combined with map overlays illustrating tourist destinations, transport infrastructure, activity settings and travel flows, using ArcView GIS software. The second objective used a quantitative methodology involving a postal survey to gain insights into the total population of tourism operators around the Southern Alps, which generated a 51% response rate. It investigated operator perceptions of regional seismic risk, their perceived level of preparedness, and the factors that influence the resilience of tourism businesses. A third methodological tool involved semi-structured interviews with key tourism stakeholders and tourism business operators to add greater depth and support to the interpretation of the quantitative results. Results from objective one showed that a magnitude 8 earthquake is likely to produce severe damage to infrastructure, buildings and roads, and cause lengthy interruption to human activities throughout the Southern Alps. Widespread landsliding will cause an immediate drop in visitation due to road closures, with long-term repair work (> 6 months) required to restore access. Visitors in many small, remote, tourism-based communities will be left stranded for a period of days until emergency authorities begin evacuating those most in need, adding to the immediate burden on communities. Medium to long-term recovery outcomes may be hampered by on-going aggradation of sediment in fluvial systems, particularly on the western side of the Alps. Post-disaster recovery in terms of visitation is predicted to take approximately 12-18 months, depending on the timing of the earthquake. Objective 2 results suggested tourism operators understand the likelihood of an earthquake on the Alpine Fault, but lack awareness of the potential consequences for their business. Business owners consider themselves to be poorly prepared for a large earthquake, although they see the benefit in taking steps to become more prepared. Emergency managers should make efforts to convert tourism operator motivations into improved business preparedness, primarily by making business preparedness information more readily available to the tourism sector. Demographic variables were found to have only weak correlation with business preparedness. Business characteristics, such as business longevity, size and turnover, had varying degrees of influence on the uptake of key resilience ‘tools’, including continuity insurance, induction, staff training and disaster planning. Levels of continuity insurance and disaster planning were found to be inadequate and in need of significant improvement in light of the expected outcomes of a future Alpine Fault earthquake on business function. To date, there has been a significant gap in our understanding about earthquakes and their potential effects on the tourism industry in New Zealand. This doctoral research project built upon the crisis management and risk perception literature by providing critical insights into the seismic risk perceptions and preparedness of business managers in a sector of the New Zealand economy growing in prominence. In addition, it brought together the study of tourism with the science of earthquakes to develop a clear illustration of the physical outcomes of a future Alpine Fault earthquake around the Southern Alps. A magnitude 8 event will cause considerable disruption to tourism activities for a prolonged period. Improvements in business preparedness and resilience are urgently needed, which could be achieved using innovative business and community-driven initiatives, with improved communication and support from government agencies.

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  • The influence of skill and low back pain on peak and cumulative spine loads during wool harvesting

    Pal, Poonam (2010)

    Doctoral thesis
    University of Otago

    Sheep shearing is a physically demanding occupation, with high energy expenditure, spinal loads and risk of back injury. The cost of injury compensation and rehabilitation for this workforce is considerable. Although research shows the use of a commercially available trunk harness will significantly reduce spinal loads, there has been no investigation of worker skill on spinal loads and risk of injury. A higher skill level is accepted by the wool harvesting industry as improving quality of work and productivity. Others within the industry consider that increased skill lowers risk of injury by improving animal control and working in less demanding postures. Some research has shown a positive effect of skill within other occupations and tasks; such as a reduction in energy expenditure, spinal cumulative loads and asymmetric movements while others have shown no such effect. The aims of this research are to quantify lumbo-sacral cumulative and peak forces experienced by workers in the wool harvesting industry, and to determine how skill and a history of low back pain requiring clinical intervention (LBP-Clin) impact on these loads. Following ethical approval a total of 140 participants (80 shearers and 60 wool handlers) were recruited and surveyed during formal shearing and wool handling competitions in Southern New Zealand. Each subject was then video-taped while executing 3 to 5 consecutive trials (dependent on skill level and competition requirements) of their normal task cycle. These video clips were analysed by using posture binning and load analysis software (3D Match) that incorporated 3D kinematics, external hand forces and anthropometric data to calculate the peak and cumulative loads on the L4/L5 segment. Cumulative loads were then extrapolated to an 8-hour work day. Correlation analysis was performed to determine collinearity between e xplanatory (independent) variables. Univariate linear regression models were initially used to determine the individual influence of skill and LBP-Clin on cumulative and peak spinal forces while multivariate linear regression models were used to determine the combined influence of skill and LBP-Clin on cumulative and peak spinal forces. For shearers mean peak lumbo-sacral compression, joint anterior shear, joint anterior reaction shear, and extensor moments for shearers were 3828.7N, 230N, 458.3N, and 185.1Nm respectively. For wool handlers these peak lumbo-sacral loads were 3194.2 N, 189.2 N, 391.4 N and 165.1 Nm. Mean cumulative compression, force weighted compression, joint anterior shear, joint anterior reaction shear, and extensor moments for shearers were 82.6 MN.s, 84.8 MN.s, 5.4 MN.s, 11.8 MN.s and 4.2MNm.s while these mean cumulative scores were considerably less for wool handlers at 48.7 MN.s, 48.9 N.s, 2.53 MN.s, 5.7 MN.s and 0.023 Nm.s. Skill was associated with decreased peak catch and drag compressive force for junior, intermediate and senior shearers and also decreased cumulative extensor moments for junior and senior wool handlers. LBP-Clin was only associated with an increased peak extensor moment during the catch and drag for shearers while LBP-Clin had no significant influence on any peak or cumulative force for wool handlers. The interaction variable for skill and LBP-Clin also showed no significant influence on peak or cumulative forces for either shearers or wool handlers. Although this study demonstrates minimal influence for skill or LBP-Clin (or their interaction) on cumulative and peak cumulative and anterior shear forces, the prevalence of LBP-Clin within each skill level increases considerably (particularly for shearers). Interestingly increased skill is also strongly predictive of a considerable increase in productivity (or tally). Thus increased skill appears to be primarily beneficial in terms of increased wool production and task efficiency. Further research with a larger within-skill sample size and prospective design is needed to confirm these results. Other biomechanical factors such as body position within working postures, time spent in different postures, harvesting techniques, and non-sagittal postures and forces (medio- lateral shear and reaction forces) may also be linked to skill and LBP-Clin. Exploring the effect of these other biomechanical factors continues within the occupational biomechanics research team at the University of Otago. Similarly personal and psychosocial factors are recognised as being linked to injury and injury risk within the overlapping fields of ergonomics and occupational health. The part they play in injury risk within the wool harvesting occupations is unknown and is also under exploration. A recommendation for the wool harvesting industry is to continue with formal skill training as it does not appear to expose the worker to increased cumulative or peak spinal loading and it is strongly associated with productivity. However the marked increase in working lifetime prevalence of LBP-Clin in this physically demanding occupation is clearly a problem and it may be that exposure to such high compressive and shear forces (independent of skill) exceeds yet to be determined cumulative loading thresholds that lead to risk of low back injury. While postural demands and non-sagittal forces during traditional shearing also need to be investigated, development of alternative upright posture wool harvesting strategies is an industry identified direction for reduction of injury risk that is biomechanically sound and now under investigation.

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  • Deci-belles: Gender and Power in Sound Engineering for Popular Music in New Zealand

    Smith, Dianne Marie (2010)

    Doctoral thesis
    University of Otago

    This thesis is a study in gender relations in sound engineering for contemporary rock music in New Zealand. I contend that music audiences and music industry workers alike discursively construct sound engineering as a masculine activity. Men greatly outnumber women in the field of sound engineering, and because the occupation is vertically segregated by gender, men also occupy positions of authority. This thesis explores the problems women face navigating a male-dominated occupation, and the tactics they employ to establish themselves within the industry. Through semi-structured interview processes with both male and female sound engineers, I was able to identify key themes in their perspectives on their work. Women sound engineers face entry level and on-the-job gender discrimination. I argue that the technological tools they use are seen as being at odds with femininity. They persist despite this, fulfilling their desires for creative input into music. As part of a collaborative team in the production of local rock music, sound engineers are in the position to help shape its sound. The power exercised within music production is not equally accessible to women, and this is one factor among many which upholds gender inequality in the music industry.

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