1,480 results for Scholarly text, Doctoral

  • Modernizing Childbirth in Colonial Bengal: A History of Institutionalization and Professionalization of Midwifery, c.1860-1947

    Guha, Ambalika (2015)

    Doctoral thesis
    Victoria University of Wellington

    In colonial India, medicalization of childbirth has been historically perceived as an attempt to ‘sanitise’ the zenana (secluded quarters of a respectable household inhabited by women) as the chief site of birthing practices and to replace the dhais (traditional birth attendants ) with trained midwives and qualified female doctors. This thesis has taken a broader view of the subject but in doing so, focusses on Bengal as the geographical area of study. It has argued that medicalization of childbirth in Bengal was preceded by the reconstitution of midwifery as an academic subject and a medical discipline at the Calcutta Medical College. The consequence was the gradual ascendancy of professionalized obstetrics that prioritised research, surgical intervention and ‘surveillance’ over women’s bodies. The thesis also shows how the medicalization of childbirth was supported by the reformist and nationalist discourses of the middle-class Bengalis in the late nineteenth and early twentieth centuries. The thesis begins from the 1860s when the earliest scientific essays on childbirth and pregnancy began to appear in Bengali women’s magazines such as Bamabodhini Patrika. It ends in the 1940s, when nationalism profoundly influenced the professionalization of obstetrics - midwifery being perceived as the keystone in a nation’s progress. Bengal being the earliest seat of British power in India it was also the first to experience contact with the western civilization, culture and thought. It also had the most elaborate medical establishment along western medical lines since the foundation of the Calcutta Medical College in 1835. It is argued in the extant literature that unlike the West where professionalized obstetrics was characterised as essentially a male domain, the evolving professional domain of obstetrics in Bengal was dominated by female doctors alone. Questioning that argument, the thesis demonstrates that the domain of obstetrics in Bengal was since the 1880s shared by both female and male doctors, although the role of the latter was more pedagogic and ideological than being directly interventionist. Together they contributed to the evolution of a new medical discourse on childbirth in colonial Bengal. The thesis shows how the late nineteenth century initiatives to reform birthing practices were essentially a modernist response of the western educated colonized middle class to the colonial critique of Indian socio-cultural codes that also included an explicit reference to the ‘low’ status of Bengali women. Reforming midwifery constituted one of the ways of modernizing the middle class women as mothers. In the twentieth century, the argument for medicalization was further driven by nationalist recognition of family and health as important elements of the nation building process. It also drew sustenance from international movements, such as the global eugenic discourse on the centrality of ‘racial regeneration’ in national development, and the maternal and infant welfare movement in England and elsewhere in the inter-war years. The thesis provides a historical analysis of how institutionalization of midwifery was shaped by the debates on women’s question, nationalism and colonial public health policies, all intersecting with each other in Bengal in the inter-war years. The thesis has drawn upon a number of Bengali women’s magazines, popular health magazines, and professional medical journals in English and Bengali that represent both nationalist and official viewpoints on the medicalization of childbirth and maternal and infant health. It has also used annual reports of the medical institutions to chart the history of institutionalization of midwifery and draws upon archival sources - the medical and educational proceedings in particular - in the West Bengal State Archives and the National Archives of India.

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  • The impact of intellectual capital on firm performance among R&D engaging firms

    Ariff, Arifatul Husna Mohd (2016)

    Doctoral thesis
    Victoria University of Wellington

    This thesis investigates the impact of aggregate intellectual capital (IC), and its elements, human capital, structural capital and tangible capital, on firm performance. In addition, the study also examines the impact of past research and development (R&D) activity on the relationship between IC and firm performance. The study employs the original and modified Value Added Intellectual Coefficient (VAICTM) models to measure IC. Firm performance is measured from two different perspectives: market and financial. The study uses a sample of 1,328 firm-year observations drawn from multinational firms which engaged in R&D activity over the period 2006-2013 and were listed on the U.S. stock exchanges. Using ordinary least squares regression, the study confirms that aggregate IC has a significant positive impact on both the market and financial performance of firms. Human capital has no significant impact on market performance, but it has a significant positive impact on financial performance. Structural capital and tangible capital each have a significant positive influence on both the market and financial performance of firms. In addition, the study finds that past R&D activity has a significant positive impact on the relationship between aggregate IC and both market and financial performance. However, the study finds mixed results for the role of past R&D activity on the relationship between the IC elements and firm performance. The study contributes to the existing literature by providing empirical evidence on the impact of IC on firm performance among multinational R&D engaging firms. The study also adds to the literature by providing empirical evidence on the role of R&D activity in influencing the relationship between IC and firm performance and thus enhances the current understanding of the role of IC and R&D. In addition, the study contributes to the methodology by proposing a modification to the original VAIC model and empirically tests the resulting modified VAIC model. The study thus provides empirical evidence of the impact of IC on the market performance and financial performance of firms. This evidence should be useful to firms in developing their IC and R&D policies, to users of financial statements in evaluating the benefits from IC among R&D engaging firms, and also to accounting standard setters in identifying the information on IC that should be included in financial reports.

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  • Nanoparticle Charge and Shape Measurements using Tuneable Resistive Pulse Sensing

    Eldridge, James (2016)

    Doctoral thesis
    Victoria University of Wellington

    Accurate characterisation of micro- and nanoparticles is of key importance in a variety of scientific fields from colloidal chemistry to medicine. Tuneable resistive pulse sensing (TRPS) has been shown to be effective in determining the size and concentration of nanoparticles in solution. Detection is achieved using the Coulter principle, in which each particle passing through a pore in an insulating membrane generates a resistive pulse in the ionic current passing through the pore. The distinctive feature of TRPS relative to other RPS systems is that the membrane material is thermoplastic polyurethane, which can be actuated on macroscopic scales in order to tune the pore geometry. In this thesis we attempt to extend existing TRPS techniques to enable the characterisation of nanoparticle charge and shape. For the prediction of resistive pulses produced in a conical pore we characterise the electrolyte solutions, pore geometry and pore zeta-potential and use known volume calibration particles. The first major investigation used TRPS to quantitatively measure the zeta-potential of carboxylate polystyrene particles in solution. We find that zeta-potential measurements made using pulse full width half maximum data are more reproducible than those from pulse rate data. We show that particle zeta-potentials produced using TRPS are consistent with literature and those measured using dynamic light scattering techniques. The next major task was investigating the relationship between pulse shape and particle shape. TRPS was used to compare PEGylated gold nanorods with spherical carboxylate polystyrene particles. We determine common levels of variation across the metrics of pulse magnitude, duration and pulse asymmetry. The rise and fall gradients of resistive pulses may enable differentiation of spherical and non-spherical particles. Finally, using the metrics and techniques developed during charge and shape investigations, TRPS was applied to Rattus rattus red blood cells, Shewanella marintestina bacteria and bacterially-produced polyhydroxyalkanoate particles. We find that TRPS is capable of producing accurate size distributions of all these particle sets, even though they represent nonspherical or highly disperse particle sets. TRPS produces particle volume measurements that are consistent with either literature values or electron microscopy measurements of the dominant species of these particle sets. We also find some evidence that TRPS is able to differentiate between spherical and non-spherical particles using pulse rise and fall gradients in Shewanella and Rattus rattus red blood cells. We expect TRPS to continue to find application in quantitative measurements across a variety of particles and applications in the future.

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  • Intersections between Pacific leadership and international development

    Fernandez, Sean (2016)

    Doctoral thesis
    Victoria University of Wellington

    As part of the Millennium Development Goals, the United Nations has a long-held commitment to universal primary education for all children. Aid donors in wealthy nations have taken up this call and international development programmes have subsequently been set up in recipient countries where education is not available to everyone. Despite this, an estimated 1.6 million school-aged children in the Pacific region do not currently have access to formal primary schooling. As the timeframe for achieving the Millennium Development Goals draws to a close it is now clear that this aspiration will not be realised in many parts of the Pacific and a generation of children will grow up without a primary education. This raises questions about the design, delivery and management of international aid programmes in the education sector that are often led by people who are not members of the Pacific communities that they seek to assist. This research explores the frustrations felt by recipients of education development programmes in two nations in the Pacific, Tonga and Fiji focusing on the relationship between international development in the Pacific and leadership styles and cultures in the education sector. A key problem that was articulated by aid recipients is that international aid relationships in the Pacific continue to be dominated by the discourses and priorities of donor nations and important opportunities to develop grassroots and local forms of leadership that respond directly and knowledgeably to the rapidly changing needs of Pacific communities have yet to be fully realised. At the same time, new forms of Pacific leadership are emerging as global economies increasingly affect the lives of people living in remote communities and there is a need to respond to these changes because they have a direct impact on schooling for children who live in those areas. Donor nations have not contributed significantly to local leadership development in the education domain and this is an ongoing source of tension for many people because there are so few formally trained indigenous leaders in the education field. The lack of local leaders in this area has an impact of the level of buy-in that Pacific communities give to educational aid projects. This thesis argues that if donor nations are serious about providing universal primary education, leadership development needs to be supported more comprehensively.

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  • New Methods for Studying Materials Under Shear with Nuclear Magnetic Resonance

    Brox, Timothy Ian (2016)

    Doctoral thesis
    Victoria University of Wellington

    For over 30 years, nuclear magnetic resonance (NMR) techniques have been used to study materials under shear. Collectively referred to as Rheo-NMR, these methods measure material behaviour due to external stimuli and provide spatially and temporally resolved maps of NMR spectra, intrinsic NMR parameters (e.g. relaxation times) or motion (e.g. diffusion or flow). As a consequence, Rheo-NMR has been established as a complementary technique to conventional rheological measurements. In this thesis, new hardware and experimental methods are presented with the goal of advancing this exciting field through further integration of traditional rheometry techniques with NMR experiments. Three key areas of hardware development have been addressed, including: 1) integrating torque sensing into the Rheo-NMR experiment for simultaneous bulk shear stress measurements, 2) constructing shear devices with geometric parameters closer to those used on commercial rheometers and 3) implementing an advanced drive system which allows for new shear profiles including oscillatory shear. In addition to presenting the design and construction of various prototype instruments, results from validation and proof of concept studies are discussed. This information demonstrates that the hardware operates as expected and establishes an experimental parameter space for these new techniques. Furthermore, these methods have been applied to open questions in various physical systems. This includes exploring the influence of shear geometry curvature on the onset of shear banding in a wormlike micelle surfactant system, observing shear induced structural changes in a lyotropic nonionic surfactant simultaneously via deuterium spectroscopy and bulk viscosity as well as studying interactions of flowing granular materials. The interpretation and implication of these observations are discussed in addition to motivating further studies.

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  • "I just find it awkward": Girls' negotiations of sexualised pop music media

    Goddard, Sarah (2016)

    Doctoral thesis
    Victoria University of Wellington

    This thesis examines girls’ relationship with and consumption of female pop stars’ music media. It is contextualised within a period of extensive academic and media debate about girls’ engagement with what has been termed the sexualisation of culture. Much of the alarm concerning girls’ premature sexualisation is underpinned by the presumption of girls as passive media consumers who are uniformly influenced by sexually saturated female pop music, particularly its ubiquitous representation of hyper (hetero) sexually desiring femininity. The notion of girls as precociously sexualised by hypersexual female pop music media has gained homogenous status within mainstream media and popular psychology texts. Girls’ pleasurable consumption and negotiation of a sexually laden media landscape is approached in this research as complicated by their contradictory positioning as savvy consumers within the postfeminist girlhood consumer market and simultaneously as victims within mainstream media and academic literature. Grounded in feminist poststructuralist understandings of girls’ subjectivity, the thesis explores the possibilities of self that representations within female pop music media enable and constrain for girls. Furthermore, the thesis explores ways in which girls make sense of these discourses while carefully managing their positioning as consumers. The research upon which this thesis is based has two parts. Part one of the research involved focus groups within which 30 pre-teen girls, identifying as ‘Kiwis’ or ‘New Zealanders’ discussed their engagement with female popular music media. The second part comprises a thematic discursive and semiotic analysis of girls’ self-recorded group video performances to a favourite pop song by a female artist. Discursive analysis of the professional music videos on which girls’ performances were based accompanied analyses of girls’ videos. The thesis contributes to a growing body of critical feminist research which responds to sexualisation claims that underpin hegemonic understandings of contemporary girlhood. The analyses presented in the research challenge moralistic notions of girls as uniformly influenced by pop music media by highlighting their navigation of this media as a contradictory process of appropriation and rejection. This complex negotiation, while seen in previous feminist literature, is uniquely captured within this thesis through the innovative employment of a performance method that extends feminist theorisations which problematise binary assumptions of girls’ engagement with sexualised media. This research identifies girls’ meaning making as a contradictory and plural process and provides novel insights about girls’ negotiation of postfeminist femininities in their own self-making in relation to self. Crucially, the thesis highlights the way in which girls’ navigation of sexualised media can be understood as occurring through both rejection and reproduction of postfeminist femininity ideals. Contextualised in New Zealand, the research extends knowledge about girls’ navigation of sexualised media beyond a US/UK social context. It also advances the small body of New Zealand literature about girls’ media engagement broadly and about the ways they experience sexualised media in particular.

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  • Exploring the use of ICTs in non-profit sector organisations: supporting the third act

    Priyanga De Silva Senapathy, Nishanie (2016)

    Doctoral thesis
    Victoria University of Wellington

    Life after retirement from full-time work is known as the third act of an individual. In New Zealand the third act has become longer, resulting in an ageing population. An implication of population ageing is the need for increased support and services for older people who live within the community. Non-profit sector organisations primarily cater to those that are either beyond the reach of state services or are unable to afford services offered by the commercial sector. This study is guided by the central research question: how can non-profit sector organisations use ICTs to support service provision for older people living within the community? Using Lamb and Kling’s social actor model, adapted to the context of non-profit sector, the research project explores how ICT use is influenced by factors that are investigated under four key dimensions: affiliations, environment, identities and technology. Employing a case research method, it studies ICT use in four human services non-profit sector organisations. The analysis of the case studies revealed how external influences are enacted within organisations. The study presents a framework which explains post-adoptive use in non-profit sector organisations incorporating external factors, the organisational view and social actor behaviours. The findings suggest that client and funder information requirements influence organisations to select one of four responses to external cues. Organisations adopt either a complementary perspective, a competing perspective, a compatible view or a negotiated view. These organisational information perspectives craft social actor behaviours within non-profit organisations. Further, this study found information challenges associated with maintaining complex client requirements. Mobility of the work force, deficiencies in data capture and limitations of existing client information systems constrain information flow in these organisations. As a result analysis of service utilisation data fails to communicate the actual value created within communities. This study has extended the understanding of ICT use in non-profit human services organisations in New Zealand and contributed to knowledge in the development of the social actor model within specific contexts. The original contribution of this study is the three-tier typology of social actor- information roles. The study presents social actor behaviour associated with a primary entity and an information role. Five main social actor- information roles were identified across three tiers and have been mapped against a spectrum of information behaviours associated with each role. When responding to external cues social actors engage in task related behaviours associated with their information roles. By contributing to ICT use practices, this research presents new perspectives on the components of value in organisational processes. Identifying value adding and value communicating information flows, information loss and informal ICT support roles this study presents a detailed analysis of the factors that enhance and constrain ICT use within human services non-profit sector organisations.

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  • Behavioural and Neurochemical Effects of Acute (±) 3,4 methylenedioxymethamphetamine (MDMA) in the Dopamine D1 Receptor Mutant Rat

    Squire, Hanna (2016)

    Doctoral thesis
    Victoria University of Wellington

    Rationale: (±) 3,4-methylenedioxymethamphetamine (MDMA; ‘ecstasy’) is a recreationally abused psychostimulant that leads to detrimental effects on memory performance. MDMA’s acute effects on memory are often attributed to a working memory impairment resulting from compromised serotonin systems. However, recent evidence from non-human animal experimental studies suggests that acute MDMA may impair memory performance through an MDMA-induced increase in dopamine (DA) release, leading to overstimulation of DA D1 receptors. The overstimulation of D1 receptors during acute MDMA exposure is thought to indirectly impair memory by increasing a subject’s susceptibility to proactive interference, leading to a perseverative pattern of responding during memory tasks. Objective: This project investigates the hypothesis that acute MDMA impairs memory performance via overstimulation of D1 receptors. The acute actions of MDMA will be assessed using DA D1 mutant (DAD1-/-) rats which possess a selective down-regulation in functional DA D1 receptors. On the basis that acute MDMA impairs memory function via overstimulation of D1 receptors it is predicted that, compared to control rats, DAD1-/- rats will be protected from the acute memory deficits caused by MDMA. Due to the novelty of the DAD1-/- rat model, prior to the assessment of the acute effects of MDMA on memory performance in these rats, behavioural and neurochemical characterisations will be conducted. Methods: Firstly, a behavioural characterisation was conducted to explore the tendencies of DAD1-/- rats, compared to controls, in a drug free state. Behaviours relevant for motivation and reward, movement, and memory were the focus of the behavioural investigation due to evidence suggesting a role for D1-like receptors in these functions. Secondly, a neurochemical assessment of DAD1-/- and controls rats in response to MDMA (3 mg/kg) was assayed using c-fos expression, a marker for neuronal activity, in several brain regions with known DA innervation. Thirdly, to assess the acute effects of MDMA on memory performance, DAD1-/- and control rats were trained on a spatial working memory T-maze task, delayed non-matching to position (DNMTP), over 25 sessions. Once trained, rats were administered either MDMA (1.5, 2.25 and 3 mg/kg) or saline fifteen minutes prior to testing on DNMTP, with all subjects experiencing all drug doses three time each. In addition, to further investigate the hypothesis that overstimulation of D1 receptors impairs memory performance, the effects of a D1 receptor agonist, SKF 81297 (0.5, 1, 1.5, 3, 4.5 mg/kg) on DNMTP performance were also assessed. Results: The behavioural characterisation revealed that DAD1-/- rats are capable of performing many behaviours relevant for reward processing, movement and memory function. However, DAD1-/- rats were impaired with regard to some reward-related behaviours, such as the acquitision of lever pressing for sugar pellets. The assessment of c-fos expression demonstrated that DAD1-/- rats express less c-fos in the medial prefrontal cortex, striatum and nucleus accumbens compared to control rats following MDMA administration. Lastly, the effects of acute MDMA administration on memory performance were tested. During the third block of MDMA administration, control rats demonstrated decreased accuracy on the DMNTP task at both the 2.25 and 3 mg/kg doses. The decrease in accuracy during MDMA exposure in control rats was driven by an increase in perseverative errors. On the contrary, DAD1-/- rats were not impaired on the DNMTP task following acute MDMA at any of the doses tested. Administration of SKF 81297 did not lead to any systematic changes in performance, but at the 3 mg/kg dose DAD1-/- rats displayed increased accuracy compared to control rats. Conclusions: DAD1-/- rats were protected from an MDMA-induced decrease in accuracy on the DNMTP task compared to control rats. This finding challenges the assumption that MDMA’s acute effects on memory performance are wholly due to serononergic mechanisms. Specifically, the current study provides evidence for the hypothesis that acute MDMA exposure impairs memory performance in rats.

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  • The impacts of ocean acidification and warming on the Antarctic bivalve, Laternula elliptica

    Bylenga, Christine Heather (2016)

    Doctoral thesis
    Victoria University of Wellington

    Laternula elliptica are large bivalves found in high densities in soft sediments in coastal regions of the Southern Ocean. L. elliptica form an important part of the ecosystem, due to significant sediment stabilisation and deposition. Despite the important role L. elliptica play in their environment, little is known about how projected ocean change will impact future populations of this species. Invertebrate larvae are considerably more sensitive to environmental stressors than juveniles and adults, and increases in mortality and minor reductions in dispersal could significantly reduce future population sizes. In a rapidly changing climate, some of the greatest changes are expected at high latitudes. The greatest rates of warming of surface waters are occurring in the Southern Ocean. Additionally, undersaturation of aragonite due to ocean acidification is expected to affect these waters within decades. Calcifying organisms such as molluscs may be particularly sensitive to reduced pH and saturation states associated with ocean acidification. However, information on larval responses to these stressors in Antarctic species is limited. The larvae of L. elliptica are large and lecithotrophic. Maternally provided energy reserves sustain development until the completion of metamorphosis. While large reserves may support long development times and extended encapsulation, they are finite and cannot be replenished. Any stress during larval development could increase metabolic costs and deplete reserves, preventing metamorphosis. These stressors may also impact the calcification process and shell structures, resulting in weaker larvae at settlement that are more vulnerable to injury. Small reductions in larval survival could limit recruitment and population growth may decline. Various responses to ocean acidification (OA) and warming were studied in the larvae of L. elliptica. Larvae were raised under control pH and temperatures (~8.00 and - 1.7°C, respectively) and conditions representing projections for the Antarctic by the end of the century and 2300 (pH 7.80, 7.65 and -0.5, +0.5 and +1.5°C), both individually and in combination. The effect of these stressors on fertilisation rates, development timing and rates of abnormalities at various life stages were examined. Furthermore, SEM analysis determined the impacts of OA and warming on larval shell growth and morphology. Respiration rates and lipid reserves in developing larvae were also determined. Information on OA and temperature responses in Antarctic larvae is limited, and this is the first study on the effects of these stressors in Antarctic bivalves. Elevated temperatures largely improved development, increased early fertilisation rates, and accelerated development through all larval stages and larvae reached competency 5 d ahead of larvae at the control temperature. This would allow for faster settlement, significantly reducing time spent in more vulnerable development stages. Elevated temperatures also improved calcification in later D-stage larvae increasing shell lengths and reducing pitting and cracking, suggesting these larvae will be in a better condition at settlement. Reduced pH improved fertilisation at control temperatures, but impaired it at elevated temperatures, although overall fertilisation was greater at pH 7.65/0.4°C compared to the control temperatures (60% and 50%, respectively). Developmental delays were observed at reduced pH; however the effect varied between experiments. In the first, developmental delays due to reduced pH were observed at all experimental temperatures and were greatest at 0.4°C, while in the second experiment, delays only occurred at ambient temperature. The delay at ambient temperature was 2 d in both experiments. The delaying effect in the first experiment was mitigated by the overall faster development with elevated temperature. Larvae at pH 7.65/0.4°C reached competency at 22 d compared to 24 d at pH 7.98/-1.6°C. Larvae from the most extreme treatment (pH 7.65 and 0.4°C) still reached the D-larvae stage two days ahead of those at control conditions (pH 7.98 and -1.6°C). This also was the first study to perform a detailed analysis of the effect of pH and temperature on shell size and ultra-structure in Antarctic bivalve larvae. D-larvae from reduced pH treatments had significantly larger shells at elevated temperatures. While light microscopy suggested no significant effect of pH on development, SEM analysis revealed that reduced pH severely impaired the quality of the larval shell at all temperatures. They were more likely to have abnormal larval shapes, as well as malformed hinges and edges. These malformations will carry over into juvenile stages, impairing swimming and feeding capacity, which would reduce settlement success and condition. Additionally, these larvae had lower shell integrity, with high frequencies of pitting and shell damage, including cracking under reduced pH, although elevated temperatures partially ameliorated this effect. Larval shells at reduced pH were weaker, indicating they will be more susceptible to injury and predation. This would flow on to later life-history stages, impairing success in settlement when juveniles must bury in the sediments. This is the second study, and the first for molluscs and Antarctic species, to perform a detailed biochemical analysis of the use of energetic reserves in larvae in response to OA. The larvae of L. elliptica are lecithotrophic, depending on maternally provided energy for development to competency. However, the composition and size of the reserves were unknown. The lipid reserves in the larvae were large, dominated by triacylglycerols and phospholipids. Despite significant depletion of both these lipid classes during development, more than 65% of the original lipid pool remained at the D-larval stage, suggesting significant reserves exist for later metamorphosis. Higher metabolic rates are expected in response to pH and temperature stress and supporting these rates may be energetically demanding. However, larvae did not alter use of any of the lipid classes at elevated temperatures. Increases in oxygen consumption in the larvae at elevated temperature indicated low temperature tolerances in L. elliptica larvae, possibly around -0.5°C. These may place increased energetic demands on later life stages that cannot depend on maternally provided resources. Under OA, the energetic demands of calcification are expected to increase due to the costs of active maintenance of the pH of cellular fluids. However, respiration rates were unaffected by reduced pH and a greater lipid reserve remained in larvae at pH 7.65/-1.7°C compared to all other treatments, suggesting larvae may respond to OA by reducing calcification. Additionally, the impact of reduced pH on biodeposition was assessed in adult L. elliptica. Short term (48 h) exposure to reduced pH (to pH 7.54) did not influence biodeposition rates or the organic composition of faeces and pseudofaeces, although compositional changes may have occurred in the latter due to increased mucous production or altered particle selection. Overall, some resilience to projected climate change conditions was observed in the larvae of L. elliptica. Under future elevated temperatures, larger populations could occur due to improved fertilisation as well as larvae reaching competency sooner with no added energetic costs. However, changes in respiration rates indicate that temperature tolerance thresholds are low. The increased metabolic demands with temperatures above -0.5°C could impair growth beyond the D-larval stage, when they are no longer dependent on maternally provided energetic reserves. Additionally, larvae may be compromised by reduced pH, as shell quality and integrity were significantly impaired. This could significantly influence recruitment and mortality rates in settlement, exposing larvae to crushing fractures in burial or reducing burial capacity. Even with slightly greater larval numbers and faster development, an overall population decline would occur if larvae fail in settlement. This study has shown that the larvae of L. elliptica are highly sensitive to future ocean change conditions, but future studies of later life history stages are needed to confirm the impacts of these changes on the greater population.

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  • Seismic investigations of the lithosphere in an amagmatic back-arc region: North Island, New Zealand

    Dimech, Jesse-Lee (2016)

    Doctoral thesis
    Victoria University of Wellington

    New seismic constraints on crustal and upper mantle structures, kinematics, and lithospheric rheology are reported from an amagmatic back-arc region: the southwest North Island of New Zealand. Robust earthquake locations reveal a hypocentre 'downwarp' beneath the east-west trending Taranaki–Ruapehu Line. These earthquakes occur in the uppermost mantle, at depths of 30–50 km, and are distinct from shallower 8–25 km-deep earthquakes near Mt. Ruapehu in terms of focal mechanisms and principal stress directions. A receiver function CCP stack shows that the mantle earthquakes occur beneath a large change in crustal thickness, where the Moho 'steps' from 28 to 35 km-deep and the steepest part of that step has a 20–50° dip. The mantle earthquakes are dominated by strike-slip fault movement and have a maximum compressive stress direction of NE–SW. The existence of mantle earthquakes beneath a steeply-dipping Moho step implies some sort of dynamic modication is occurring in the mantle lithosphere. One possibility to explain these features is the convective removal of the mantle lithosphere due to a Rayleigh–Taylor-type instability. South of the Taranaki–Ruapehu Line, the Moho conversion weakens on both the receiver function CCP stack, and marine seismic reflection data under most of the Wanganui Basin (SAHKE02 and GD100 seismic lines). However, localised bright reflections at Moho depths can be seen in both near-vertical and wide-angle seismic data. Attribute analysis of near-vertical seismic reflections suggests that the rocks beneath the reflectivity are strongly-attenuating (Q ~20) with a negative velocity contrast relative to the lower crust. These observations are interpreted to be related to the presence of serpentinite (antigorite) and/or high pore fluid pressures in the mantle wedge. The links between hydration of amagmatic back-arcs, serpentinisation and/or high pore fluid pressures, rock viscosity, and mantle instabilities are documented here for the southwest North Island of New Zealand. These associations may be applicable to other amagmatic back-arcs around the world.

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  • The role of 5-HT1A and 5-HT1B receptors in MDMA self-administration

    Aronsen, Dane (2016)

    Doctoral thesis
    Victoria University of Wellington

    Rationale: 3,4-methylenedioxymethamphetamine (MDMA) is a less efficacious reinforcer than other drugs of abuse. However, following repeated self-administration, responding increases for some animals and efficacy becomes comparable to other drugs of abuse. MDMA-stimulated serotonin (5-HT) release was negatively associated with acquisition of MDMA self-administration, and a neurotoxic 5-HT lesion reduced the latency to acquire self-administration. These findings suggest that MDMA-produced 5-HT release is an important component of self-administration. The receptor mechanisms are not, however, well understood, although it has often been suggested that the mechanism involves 5-HT-mediated inhibition of dopamine. Both 5-HT1A and 5-HT1B receptors are well localised to regulate dopamine release, and both have been implicated in modulating the reinforcing effects of many drugs of abuse. Objectives: The first objective was to establish specific behavioural assays to reflect 5-HT1A and 5-HT1B receptor activation. Then, using the established behavioural assays, the aim was to determine the role of 5-HT1A and 5-HT1B receptors in the acquisition of MDMA self-administration. The impact of substantial MDMA self-administration on 5-HT1A and 5-HT1B receptors was also assessed. Methods: Firstly, dose-effect relationships for the hyperactive response to the 5-HT1A receptor agonist, 8-OH-DPAT (0 – 3.0 mg/kg) and the hyperactive and adipsic response to the 5-HT1B/1A receptor agonist, RU 24969 (0 – 3.0 mg/kg) were determined. Selectivity of these responses was determined by co-administration of the 5-HT1A receptor antagonist, WAY 100635, or the 5-HT1B/1D receptor antagonist, GR 127935. Secondly, a pretreatment regimen of the RU 24969 (2 × 3.0 mg/kg/day, 3 days), which had been suggested to down-regulate 5-HT1B/1A receptors, was administered prior to self-administration testing. The effect of this manipulation on both the acquisition of MDMA self-administration, and the behavioural responses to 5-HT1A and 5-HT1B receptor activation, was measured. A further study measured behavioural responses to 5-HT1A or 5-HT1B receptor agonists prior to self-administration, to determine whether the variability in these responses would predict the variability in the latency to acquisition of MDMA self-administration. Lastly, the effect of substantial MDMA self-administration (350 mg/kg) on dose-response curves for the behavioural effects of 5-HT1A or 5-HT1B receptor activation was assessed. Results: The hyperactive response to the 5-HT1B/1A receptor agonist, RU 24969, was blocked by the 5-HT1A receptor antagonist, WAY 100635, but not the 5-HT1B receptor antagonist, GR127935. Similarly, the hyperactive response to the 5-HT1A receptor agonist, 8-OH-DPAT, was dose-dependently blocked by WAY 100635. GR 127935, but not WAY 100635, blocked the adipsic response to RU 24969. Repeated administration of RU 24969 produced rightward shifts in the dose-response curves for 8-OH-DPAT-produced hyperactivity and RU 24969-produced adipsia, and also greatly facilitated the acquisition of MDMA self-administration. However, there was no correlation between latency to acquire MDMA self-administration and the hyperactive response to 8-OH-DPAT or the adipsic response to RU 24969, and MDMA self-administration failed to alter these behavioural response to activation of 5-HT1A or 5-HT1B receptors. Conclusions: The hyperactive response to 8-OH-DPAT and the adipsic response to RU 24969 reflect activation of 5-HT1A and 5-HT1B receptors, respectively. The variability in acquisition of MDMA self-administration was reduced by a treatment that also down-regulated 5-HT1A and 5-HT1B receptors, however there was no further indication that these receptors play a critical role in the self-administration of MDMA. Instead, it seems likely that other 5-HT receptors have a greater impact on MDMA self-administration.

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  • Directing: A Mirror to Solo Performance Provocation, Collaboration and Proxy Audience

    Richards, Sally (2016)

    Doctoral thesis
    Victoria University of Wellington

    Solo performance is a challenging, immediate and exhilarating form of theatre. Its popularity in the field of westernised contemporary theatre is evidenced in the increasing programming of solo performances at international festivals and in commercial theatres. However, whilst there is considerable analysis of the genre of solo performance there is little examination of the relationship between director and solo performer in the rehearsal room. Prior research has focused on the theoretical or on the practical, but rarely have the two approaches actively engaged with each other. This thesis contributes a much-needed analysis of directing practice in this area, and an integration of theory and practice that offers tangible approaches in the rehearsal room. In what ways can the director best serve the solo performer to create a theatrical experience that can hold the audience's attention, imagination and memory? Solo performance is characterised by a heightened presence in both performer and audience, incited by a minimalism that abandons the theatrical premise of artifice and turns to primary storytelling. The rehearsal room relationship between director and solo performer also shares these qualities, heightened and focused by the one-one engagements. Directing in this context contrasts from that of a multi-cast, with distinctly different dynamics arising from an artistic collaboration between two people, rather than with many. This thesis considers how the director is placed as a flexible paradigm as proxy audience and as a bidirectional-mirroring device in the rehearsal process – situating the director as an articulated reflection to the transforming solo performer. I analyse this unique partnership and focus primarily on strategies that directors use to create effective solo performance. This thesis is comprised of 80% critical writing and 20% for the creative/practice-based research project. I examine the particular qualities of solo performance as a genre; its theatrical origins, function and purpose, the scope of styles and forms and its potential for political and social meaning. However, my focus is on the rehearsal room processes, working predominantly with a director, rather than an analysis of the end product - the performance. I interview practitioners in the field about their rehearsal room experiences, across the spectrum of styles and forms of solo performance. My theoretical framework is centred on Practice as Research (PaR). In order to scrutinise the relationship between director and solo performer I have gained access to the rehearsal room as both director/practitioner and researcher. The PaR component of this thesis includes the analysis of the experimental rehearsal process and performance of PocaHAUNTus - a new autobiographical solo play. In addition I draw on a body of retrospective work – re-examining my direction of five solo performances that occurred prior to this thesis. Production journals, rehearsal and performance footage, interviews, communications and photographs evidence all components. My research question is not simply “Does a solo performer need a director?” Instead, my research pursues how the relationship between the two might be negotiated, asking: “In what ways can the director best serve the solo performer?” The research examines the fundamental challenges of the genre, namely: the delineation of multiple characters by a single performer, immediacy of the audience relationship to the lone performer, stage geography and scenographic choices. The research also identifies and refines practical strategies to accommodate the intensity of working one-on-one. At its best, the director-solo performer relationship is a vibrant and supportive partnership but because of its intimacy, it is often also a complex and challenging engagement. The contribution of this thesis and its originality is in a PaR model that utilises my past experience of directing solo performance, expands on this foundation through the collection of extensive interview material from a diverse range of significant directors and performers of solo work, and then pursues a new creative laboratory where I test key approaches to directing solo performance.

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  • Characterization of Groundwater with Complementary Age Tracers

    Beyer, Monique (2015)

    Doctoral thesis
    Victoria University of Wellington

    Groundwater age or residence time is the time water has resided in the subsurface since recharge. Depending on the application, this definition may or may not include travel through the unsaturated zone. The determination of groundwater age can aid understanding and characterization of groundwater resources, because it can provide information on e.g. groundwater mixing and flow, and volumes of groundwater and recharge. Groundwater age can be inferred from environmental tracers, such as SF₆ and tritium, that have a known input to groundwater and/or undergo known alteration processes in groundwater. The currently used age tracers face limitations regarding their application range and reliability. For example, some age tracers have local sources that can lead to contamination of groundwater. This contamination can result in misleading estimates of age. Other tracers have ambiguous inputs to groundwater, which can result in ambiguous age estimations. To reduce these limitations, it is now recognized that multiple tracers should be applied complementarily. There is also a need for new groundwater age tracers and/or new groundwater dating techniques to supplement the existing ones. Cost-effective and easily applicable tracers/techniques are preferred, since most established groundwater dating techniques are very costly and/or complex. Commonly measured hydrochemistry parameters , such as the concentrations of major ions and pH, have been suggested as cost-effective and easily determinable potential age tracers. To date, the use of commonly measured hydrochemistry parameters as independent age tracer has only been demonstrated for water recharged weeks to months ago relying on seasonal changes. Other studies applied commonly measured hydrochemistry complementarily to established age tracers to better constrain groundwater age and/or better understand and predict anthropogenic effects on groundwater quality. Further study is needed to assess the extent to which commonly measured hydrochemistry can be used to reduce uncertainty in tracer-inferred age as well as the extent to which commonly measured hydrochemistry can be used to extrapolate tracer-inferred age. In addition to tracer specific limitations, quantification of uncertainty and ambiguity is not standard in age modelling. Although a few studies have attempted to quantify uncertainty in age modelling with the aid of probabilistic approaches, their methods are often relatively complex and not transferrable to the many cases with little available data. Uncertainties in the tracer’s recharge estimate and identification of appropriate model components, such as the objective function, have not been considered. Studies in other areas of hydrological modelling, where probabilistic approaches are more commonly used, have highlighted the need for careful identification of model components.

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  • Learning Feature Selection and Combination Strategies for Generic Salient Object Detection

    Naqvi, Syed (2016)

    Doctoral thesis
    Victoria University of Wellington

    For a diverse range of applications in machine vision from social media searches to robotic home care providers, it is important to replicate the mechanism by which the human brain selects the most important visual information, while suppressing the remaining non-usable information. Many computational methods attempt to model this process by following the traditional model of visual attention. The traditional model of attention involves feature extraction, conditioning and combination to capture this behaviour of human visual attention. Consequently, the model has inherent design choices at its various stages. These choices include selection of parameters related to the feature computation process, setting a conditioning approach, feature importance and setting a combination approach. Despite rapid research and substantial improvements in benchmark performance, the performance of many models depends upon tuning these design choices in an ad hoc fashion. Additionally, these design choices are heuristic in nature, thus resulting in good performance only in certain settings. Consequentially, many such models exhibit low robustness to difficult stimuli and the complexities of real-world imagery. Machine learning and optimisation technique have long been used to increase the generalisability of a system to unseen data. Surprisingly, artificial learning techniques have not been investigated to their full potential to improve generalisation of visual attention methods. The proposed thesis is that artificial learning can increase the generalisability of the traditional model of visual attention by effective selection and optimal combination of features. The following new techniques have been introduced at various stages of the traditional model of visual attention to improve its generalisation performance, specifically on challenging cases of saliency detection: 1. Joint optimisation of feature related parameters and feature importance weights is introduced for the first time to improve the generalisation of the traditional model of visual attention. To evaluate the joint learning hypothesis, a new method namely GAOVSM is introduced for the tasks of eye fixation prediction. By finding the relationships between feature related parameters and feature importance, the developed method improves the generalisation performance of baseline method (that employ human encoded parameters). 2. Spectral matting based figure-ground segregation is introduced to overcome the artifacts encountered by region-based salient object detection approaches. By suppressing the unwanted background information and assigning saliency to object parts in a uniform manner, the developed FGS approach overcomes the limitations of region based approaches. 3. Joint optimisation of feature computation parameters and feature importance weights is introduced for optimal combination of FGS with complementary features for the first time for salient object detection. By learning feature related parameters and their respective importance at multiple segmentation thresholds and by considering the performance gaps amongst features, the developed FGSopt method improves the object detection performance of the FGS technique also improving upon several state-of-the-art salient object detection models. 4. The introduction of multiple combination schemes/rules further extends the generalisability of the traditional attention model beyond that of joint optimisation based single rules. The introduction of feature composition based grouping of images, enables the developed IGA method to autonomously identify an appropriate combination strategy for an unseen image. The results of a pair-wise ranksum test confirm that the IGA method is significantly better than the deterministic and classification based benchmark methods on the 99% confidence interval level. Extending this line of research, a novel relative encoding approach enables the adapted XCSCA method to group images having similar saliency prediction ability. By keeping track of previous inputs, the introduced action part of the XCSCA approach enables learning of generalised feature importance rules. By more accurate grouping of images as compared with IGA, generalised learnt rules and appropriate application of feature importance rules, the XCSCA approach improves upon the generalisation performance of the IGA method. 5. The introduced uniform saliency assignment and segmentation quality cues enable label free evaluation of a feature/saliency map. By accurate ranking and effective clustering, the developed DFS method successfully solves the complex problem of finding appropriate features for combination (on an-image-by-image basis) for the first time in saliency detection. The DFS method enables ground truth free evaluation of saliency methods and advances the state-of-the-art in data driven saliency aggregation by detection and deselection of redundant information. The final contribution is that the developed methods are formed into a complete system where analysis shows the effects of their interactions on the system. Based on the saliency prediction accuracy versus computational time trade-off, specialised variants of the proposed methods are presented along with the recommendations for further use by other saliency detection systems. This research work has shown that artificial learning can increase the generalisation of the traditional model of attention by effective selection and optimal combination of features. Overall, this thesis has shown that it is the ability to autonomously segregate images based on their types and subsequent learning of appropriate combinations that aid generalisation on difficult unseen stimuli.

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  • "Western thoughts, Eastern feelings": A study of filial piety and elder mistreatment among Korean immigrants in New Zealand

    Park, Hong-Jae (2011)

    Doctoral thesis
    University of Canterbury Library

    Thesis available in print.

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  • SYNTHESIS AND COMPLEXES OF BRIDGING HETEROCYCLIC LIGANDS

    Rajan, Siji (2014)

    Doctoral thesis
    University of Canterbury Library

    Ligand–mediated coupling between metal centres is of fundamental importance in inorganic and materials chemistry. Bridging ligands involving azo groups as coordinating π–acceptors can yield complexes with interesting properties. This thesis describes the synthesis of a series of N–heterocyclic compounds containing the azo functionality, designed for potential coordination to the metal through the azo nitrogen and a N–heterocyclic ring. The azo ligands are divided into four categories; ligands based on azobispyridines, ligands containing pyrimidine and fused aromatic azine groups and ligands capable of coordinating in a bis–tridentate fashion to the metal centre. Ligands containing flexible imine subunits connected directly, or through different spacers, are also discussed. Overall twenty one ligands were synthesised, six of which are new compounds. The coordination and metallosupramolecular chemistry of these ligands with ruthenium(II) and silver(I) metal atoms was investigated. A total of thirty five ruthenium(II) and eleven silver(I) complexes were prepared, of which thirty eight were characterised by X–ray crystallography. Mononuclear and dinuclear ruthenium(II) complexes were synthesised and characterised by a combination of spectroscopic and structural techniques. UV/Visible absorption studies and electrochemical methods were used to investigate the nature of metal–ligand and metal–metal interactions. In the mononuclear Ru(II) complexes, N–heterocyclic azo ligands act as chelating ligands forming five–membered chelate rings involving azo–N and heterocyclic–N atoms. The non–coordinated pyridine ring of the azo ligand is twisted with respect to the azo–N atom and is directed towards the adjacent bipyridine rings. Studies reveal that these azo ligands posses extremely low–lying π*–orbitals and are electron deficient. X–Ray structural analysis of the dinuclear complexes revealed short inter–metal separations of ca. 4.9 Å and electrochemical studies indicate that these ligands mediate very strong interactions between the metal centres , due to the excellent π*–acceptor properties of the azo functionality. Varying the pyridine ring of the azo ligand to pyrimidines and fused N–aromatic rings has a considerable effect on the electronic properties of these complexes. Incorporation of a pyrimidine ring facilitates the stabilisation of azo anion radicals and leads to the formation of diruthenium(II) species, bridged by radical species. The X–ray crystal structures of both these complexes were determined. The use of the hexadentate ligands coordinating in a bis–tridentate manner mediate even stronger communication between the two ruthenium centres. Ligands containing bis–pyridylimines result in weaker coupling between the metal centres in dinuclear ruthenium(II) species. A complete absence in the inter–metal communication was observed with increasing the distance and/or flexibility between the two pyridylimine units, contrary to a previous reported claim. Reaction with different silver(I) salts afforded an array of one–dimensional coordination polymers and a discrete dinuclear complex depending on the coordination strengths of the anions. The metallosupramolecular assemblies obtained were characterised mainly by X–ray crystallography, elemental analysis and mass spectrometry.

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  • Mating strategies and sperm competition in New Zealand geckos (Family Gekkonidae).

    Todd, Amanda Claire (2003)

    Doctoral thesis
    University of Canterbury Library

    Most species of reptile studied to date have polygynandrous mating systems and possess specialised sperm storage regions. Consequently, there is a high potential for sperm competition in this group. Using comparative analyses, I examined the level of sperm competition in New Zealand geckos and how this has influenced the evolution of their reproductive morphology. Across lizards and snakes, there was more than a 40-fold variation in relative testis size. New Zealand geckos fell in the middle of this range and lacked sexual dimorphism in head size, suggesting that most species have polygynandrous mating systems. I confirmed this for one species, Hoplodactylus maculatus, which is gregarious, lacks territoriality and has a courtship pattern that suggests a high level of promiscuity for both sexes. I found that hemipenis size in New Zealand geckos was positively correlated with relative testis size, suggesting that sperm competition has resulted in the evolution of larger intromittent organs. However, the surface features of the hemipenis were relatively conservative across species. Although there was no relationship between sperm length or putative sperm storage site (SST) morphology and relative testis size, species with fewer SSTs, and thus more intense sperm competition, had longer sperm. H maculatus males produced two types of sperm which differed not only in length but also in fertilising capacity, the short morph lacking DNA. This is the first known example of such sperm polymorphism in a vertebrate and may have evolved in response to sperm competition, the non-fertilising morph potentially helping to block the sperm of rival males or filling sperm storage sites. The motility of these short sperm was positively correlated with temperature; however, at higher temperatures motility declined with time, suggesting a trade-off between motility and longevity. Such temperature influences on male reproductive physiology have important implications for males of ectothermic species under sperm competition.

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  • Private finance and governance of REDD+ projects in Indonesia

    Dixon, Rowan (2016)

    Doctoral thesis
    Victoria University of Wellington

    This thesis explores the role of private finance within REDD+ (Reducing Emissions from Deforestation and forest Degradation) programmes in Indonesia. Since its debut in 2007 as a potential investment opportunity, enterprising and innovative private sector actors have moved to establish REDD+ projects within a voluntary carbon market, while the United Nations Convention on Climate Change continues negotiations to establish a comprehensive global mechanism. These profit-seeking actors have invested millions of dollars developing REDD+ projects within a rapidly evolving voluntary market that has emerged alongside the turmoil of global climate change negotiations. This dynamic market context brought about a wide variety of expressions of REDD+ in Indonesia, which this research seeks to untangle and illuminate. The thesis yields insights into the workings of market environmentalism, and complicates widespread notions of ‘private finance’ as a homogenous and predictable category of actor. In order to better understand the emergent REDD+ industry in Indonesia, and the role of private finance in shaping it, this research draws on the global value chain (GVC) framework to analyse processes of commodification and governance within REDD+ projects and ‘supply chains’. This approach identifies key private finance actors, and explores why they are involved across motivations for social, environmental and financial outcomes. It also reveals REDD+ projects as a produced commodity and provides insight into the multiple ways they are valued. The research thus highlights how private finance actors evaluate REDD+ commodities as they engage with them. These logics, and the profit-seeking rationale of private finance actors, are seen to have important governance implications in shaping the characteristics of REDD+ projects and the networks of actors involved in them. However, simultaneously, the malleable and selective characteristics of the REDD+ commodity itself shapes certain governing implications of private finance. This thesis contributes to debates concerning the commodification of nature within market environmentalism and the neoliberalisation of nature, providing insights into the nature and agency of private finance.

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  • Tensions and Possibilities. The Interplay of 'Traditional' Cultural Elements and the Creation of 'Contemporary' Rapa Nui, Māori and Samoan Diasporic Theatre

    Fortin Cornejo, Moira (2016)

    Doctoral thesis
    Victoria University of Wellington

    This thesis focuses on notions of ‘traditional’ and ‘contemporary’ theatre in two Pacific Island contexts, Aotearoa and Rapa Nui. It explores how notions of ‘tradition’ are imagined, recreated, and performed through the ‘contemporary’ creative arts, with a particular focus on theatre. It offers insight about culturally-situated understandings of ‘tradition’, and seeks to acknowledge diverse meanings and perceptions of theatre that exist across diverse Pacific Island cultures, languages, and epistemologies. Ideas about what constitutes ‘tradition’ have been significantly impacted by colonial histories, and that these culturally and historically situated ideas have wide-ranging implications for creative possibilities in the ‘contemporary’ performing arts. ‘Traditional’ performances are often seen as acceptable and relevant to Indigenous communities in Aotearoa and Rapa Nui, contributing to processes of cultural reclaiming and revitalisation. Although cultural continuity is a significant theme in Indigenous theatre in Aotearoa and Rapa Nui, the different emphasis placed upon notions of ‘tradition’ across these comparative contexts has led to very different artistic possibilities being available. In Rapa Nui there is a general reluctance in the performing arts to deviate from ‘tradition’ or to declare work as ‘contemporary.’ The reproduction of ‘traditional’ styles and stories is one response to ongoing colonialism in Rapa Nui, and to the ever present demands of the tourist industry. Māori and Samoan theatre practitioners in Aotearoa have developed theatre forms and processes that are based in cultural values and epistemologies while also being integrated with European theatre techniques, creating innovative approaches to ‘contemporary’ themes and understandings. These developments in the creative arts are supported by the availability of a wide range of theatre education opportunities. Culturally reflective and situated approaches to theatre education have enabled Indigenous theatre practitioners in Aotearoa to use theatre as a forum to express ideas and issues to the community weaving in a variety of different cultural influences, and techniques. This thesis utilised a case-study methodology and open-ended interviews, framed under the research methodology of talanoa, to interact with Māori, Samoan diasporic and Rapanui theatre practitioners, in order to explore their perceptions towards ‘traditional’ and ‘contemporary’ practices. This research focuses on the positives of cultural dialogue, and it emerges from a desire to support intercultural theatre practices in Aotearoa and Rapa Nui.

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  • Oocyte-derived forms of ruminant BMP15 and GDF9 and a theoretical model to explain their synergistic response

    Heath, Derek (2016)

    Doctoral thesis
    Victoria University of Wellington

    Bone morphogenetic factor 15 (BMP15) and growth differentiation factor 9 (GDF9) are two oocyte-secreted factors with well documented effects on ovarian follicular development and ovulation-rate. The aims of these studies were to: (i) identify the molecular forms of BMP15 and GDF9 that are produced and secreted by both the ovine and bovine oocyte using highly specific monclonal antibodies; (ii) assess the biological activity of some recombinant molecular forms of BMP15 and GDF9; (iii) visualise the various molecular forms using protein modelling techniques and; (iv) provide a hypothetical model of how oocyte-secreted form(s) of BMP15, GDF9 and their cell surface receptors may interact. Using genetic modifications and transformations of HEK293 cells, recombinant forms of ovine (o) BMP15, including a BMP15 (S356C) mutant capable of forming covalent dimers, and oGDF9 were produced. The bioactivity of these proteins was established using a rat granulosa cell proliferation bioassay. The specificity of the monoclonal antibodies MN2-61A (anti-BMP15) and 37A (anti-GDF9) used in these studies, and determination of the forms they recognise, was examined by Western blotting. The recombinant forms of oBMP15 were further interrogated by purification using both immobilised metal affinity chromatography (IMAC) and reverse phase HPLC. The BMP15 and GDF9 proteins produced and/or secreted by ovine and bovine oocytes, before and after in vitro incubation, were identified and compared with the molecular forms(s) of recombinant oBMP15 or oGDF9 using Western blotting under non-reducing, reducing and cross-linking conditions. The molecular forms of recombinant oBMP15 and oGDF9 comprise mainly mature monomers with a lesser amount of the uncleaved pro-mature form. Mature domains, in the dimeric mature form, were detected for oGDF9 and oBMP15 (S356C), but not oBMP15. These mature domains were almost entirely located within high molecular weight multimeric complexes, which likely also contain the pro-region. In contrast, BMP15 and GDF9 secreted from ruminant oocytes under in vitro conditions were found mainly in an unprocessed promature form, along with some fully processed mature domains that did not interact to form detectable mature homodimers or heterodimers. Throughout ovarian follicular development, BMP15 and GDF9 are co-expressed and it has been established that these two factors have synergistic effects on granulosa cell proliferation both in vitro and in vivo and also on follicular maturation and ovulation-rate in vivo. Moreover, the recombinant proteins oBMP15 and oGDF9 generated for this study, when added together, also demonstrated a synergistic effect in the granulosa cell proliferation assay but this was not observed for oBMP15 (S356C) and oGDF9. Currently, no adequate model has been proposed to explain how interactions between the cell membrane and forms of oocyte-derived BMP15 and GDF9 achieve their synergistic effects. To investigate this, two homology models of the promature BMP15 and GDF9 proteins were generated using promature porcine TGFB1 and human BMP9 as templates. These models, together with the previously determined forms of GDF9 and BMP15 produced by the ruminant oocyte, were used to visualise their potential interactions, both with each other and with their receptors. This report describes a model showing the possible interactions involved in a synergistic response. In this model, the mature domain is presented to the type II receptor by the proregion and heterodimers form at the level of the receptor. Differences, following heterodimerisation in the conformation and orientation between GDF9 and its type I receptor, as well as between type I and type II receptors, relative to that in homodimers, could explain how heterodimerisation leads to increased Smad3 phosphorylation and subsequent down-stream somatic cell responses.

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