14,250 results for Doctoral

  • Haematology and inflammation in infections of farmed red deer (Cervus elaphus)

    Cross, John Philip (1991)

    Doctoral thesis
    University of Otago

    xiii, 180, i, 39 leaves, [1] folded leaf :ill. (some col.) ; 30 cm. Includes bibliographical references. University of Otago department : Microbiology

    View record details
  • Habitats and macroinvertebrate fauna of the reef-top of Rarotonga, Cook Islands : implications for fisheries and conservation management

    Drumm, Darrin Jared (2005)

    Doctoral thesis
    University of Otago

    xiii, 173, [6] leaves :ill. ; 30 cm. Includes bibliographical references. University of Otago department: Marine Science. "December 2004."

    View record details
  • Open population capture-recapture models and diabetes in Otago

    Cameron, Claire (2009)

    Doctoral thesis
    University of Otago

    xiv, 207 leaves :ill., ; 30 cm Includes bibliographical references. University of Otago department: Mathematics and Statistics

    View record details
  • Care ethics and brain injury

    Butler, Mary (2008)

    Doctoral thesis
    University of Otago

    It is generally supposed that a supportive family can have an influence on outcomes for an adult with severe brain injury, but there is very little known about what effective families actually do. In this research the families of five such individuals were involved in an ethnographic project that lasted for one year. The literature review brought together insights from brain injury, care ethics, disability studies and anthropology. These insights were combined with a process of reflective equilibrium that was applied to the ethnographic material in order to determine the ethics of the carers. Ethics of care in this setting was conceived of as a positive practice ethic, rather than as a series of negative conundrums posed by the brain injury. The practice ethic shared by carers meant that they all conceived of the need created by brain injury in humanistic terms, rather than in terms of pathology. Carers demonstrated virtues appropriate to their practice as they helped the adult with brain injury to connect with aspects of ordinary life. The best outcomes for the adult with brain injury included being able to engage in productive activity and to make a place in the world. These outcomes could only be achieved with due regard for their safety and subsistence. The practice ethic of carers was demonstrated in the skills and concern that ensured a satisfactory outcome for the adult with brain injury. This research is a departure from recent research about families affected by brain injury, which has focused on the burden involved in care. An examination of what carers achieve suggests that burden may be associated with the development of caring practice. The transformative capacity of care, for both the carer and the adult with brain injury, is emphasized. However contextual factors, such as adequate compensation, are connected to the capacity of the carer to engage in good practice and these are explored also in this thesis. In particular, relevant aspects of the relationship between families and the Accident Compensation Corporation are explored.

    View record details
  • Understanding and Improving Stroke Recovery for Māori and Their Whānau

    Harwood, Matire Louise Ngarongoa (2012)

    Doctoral thesis
    University of Otago

    This thesis sought to understand ethnic disparities in stroke within Aotearoa, New Zealand, from the perspectives of Māori. Stroke burden is greatest for Māori, the indigenous peoples of New Zealand, who have higher rates and worse outcomes compared with non-Māori. Importantly for Māori with stroke, the disparity in outcomes (including dependence and quality of life) compared with New Zealand Europeans increases significantly in the 12 months after being discharged from hospital into the community. Reasons for this are not clear. The study’s aims were twofold—to provide a deeper understanding of the stroke experience for Māori with stroke and their Whānau; and to design interventions that could potentially improve stroke outcomes. A qualitative approach to the research was taken in order to gain an understanding of people’s experience, attitudes and beliefs. Constructivist grounded theory was utilized to ensure a wider focus on societal influences. The project also involved Māori as researcher and researched and sought to make a positive difference for Māori with stroke and their Whānau. These concepts fit within the Kaupapa Māori research framework which also guided the research. Five themes explaining the stroke experience were constructed from data collected from in-depth interviews with 18 Māori with stroke and nine people who identified themselves as Whānau caring for Māori with stroke. Personal context, optimal stroke care, Whānau wellbeing, a stand against discrimination and taking charge occur in isolation, or combine, to influence stroke recovery or Māori with stroke and their Whānau. The five themes were presented to three key stakeholder focus groups of Māori with stroke, Whānau of Māori with stroke, and stroke funders and providers. Two practical interventions were proposed by the groups: a DVD of role models and a person- and Whānau-centred assessment designed to engage the patient and their family in the process of recovery. This research suggests that inequity of indigenous health and rehabilitation outcomes in stroke requires a comprehensive and multi-faceted response. A stroke strategy that achieves the aspirations of Māori to take charge is required.

    View record details
  • Creating and sustaining an “effective” rural school: The critical triad – leadership, curriculum, and community

    Wright, Anne (2012)

    Doctoral thesis
    University of Otago

    This thesis examines the professional practices of rural school principals in the province of Otago, New Zealand, to describe what it is about their practices that creates and maintains effective rural schools. The underlying question for this research was, The leadership and management of effective, small, rural schools appears to pose unique problems and issues from that in larger rural and urban schools. What makes that difference? A mixed methods approach was taken, using a survey designed for the study and administered to 63 principals of rural schools in Otago. Observations of six purposively chosen principals representing a large rural school (with a role of 150 or above) and a small rural school (with a role of 60 or below) from each of the three areas of Otago: Coastal (East), South Otago, and Central Otago; and, interviews with the six principals who were observed. The survey was factor analysed and showed strong psychometric properties. It yielded background and demographic information regarding the sample, their perceptions regarding their ideals for their schools as compared to the actual situations in their schools, and their views on developing a local curriculum and the factors that made an effective rural school. The survey informed the following observation schedules and questions for the interviews, which were conducted with 6 principals chosen to represent a cross section of types of rural schools. Main findings from the study were that context mattered – small rural school leadership was shown to be different from that in large rural schools, and that for small rural schools, a local curriculum using the local community and environment for content was essential. The results are discussed in terms of the implications they have for the profession and the future training of rural educationalists, and how the results both relate to the literature, and extend the current knowledge base about rural schools.

    View record details
  • Communicative mobility and networked mediation in transnational lifeworlds: a case study of European expatriates in Australia

    Deffner, Florian (2014)

    Doctoral thesis
    University of Otago

    Transnational lifeworlds of expatriates raise exciting questions on the use and meaning of media. Network communication, and its increased communicative connectivity, allows for a borderless communicative mobility which transforms experience and meaning by multiplying and diversifying content choices and ways of interpersonal communication. To capture the mediated transformations of expatriates’ lifeworlds, this dissertation introduces the term “networked mediation” as a descriptor for new forms of mediation emerging in the context of network communication. In the micro-perspective of the lifeworld, networked mediation comprises all forms of mediation—including their interrelation—that do not exclusively correspond to traditional ‘streamings’ of mediation, such as the strict patterns of consecutive and distinct consumptions of news in the mass media age. Therefore, networked mediation, as a multi-directional and multi-dimensional form of mediation, appears to constitute new ontological dimensions of subjective experience and meaning. The construction of more complex meaningfully lived-through mediated social realities and relations are investigated through a social-phenomenological approach illuminating the transnational communicative spaces of European expatriates in Melbourne. Results reveal new mobility cultures of communication characterized by network-based communicative internalization and communicative subjectivization. Consequently, in the case of expatriates’ transnational lifeworlds, even more complex forms of networked mediation occur as they display communicative orientations to 'dual' lifeworld attachments between home and host country. Seen from this angle, the exploration of networked mediation not only illustrates and clarifies transnational communicative spaces, but also sheds light on the complex dimensions and dynamics of contemporary cultures of mediation.

    View record details
  • 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.

    View record details
  • 'Large letter'd as with thundering shout' : an analysis of typographic posters advertising emigration to New Zealand 1839 - 1875 : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Visual and Material Culture, Massey University, Wellington, New Zealand

    Thomas, Patricia Ann (2014)

    Doctoral thesis
    Massey University

    This thesis examines the role of ephemeral, typographic material in the promotion of emigration to New Zealand in the nineteenth century. It focuses on the advertising posters produced by the New Zealand Company, the Otago and Canterbury Associations, the provincial governments and Government of New Zealand. It aims to identify how advertising and typography contributed to the transfer of the promotion message from the producer to the audience in this specific historical context. For the first time a comprehensive data set of emigration posters of this period has been gathered together and examined. The posters are analysed in the context of their contemporary visual, material and print cultures, with particular reference to ephemeral printing. To account for all the historical, textual and graphic properties of the posters, the thesis develops and applies a novel, multilayered system of analysis, drawing on communication theory, social semiotic principles and Gestalt principles of composition. The posters afforded emigration promoters a visual medium for distributing audienceappropriate messages through typographic strategies. They provided promoters with the facility for fast and inexpensive messaging that was otherwise unavailable in nineteenth century communication. The thesis concludes that posters were a significant part of an early, coherent and systematic advertising campaign which utilised processes and persuasive tools that have traditionally been seen as emergent only in the late nineteenth century. This thesis establishes the value of ephemeral material and the study of graphic language when applied to the examination of historical phenomena. As well as shedding new light on these particular forms of historical design and modes of communication, it also adds a further valuable dimension to the more well-known story of nineteenth century emigration promotion by focussing on its graphic and advertising languages rather than its pictorial aspects. The investigation undertaken provides a new analytical system through which a combination of historical, ephemeral, typographic and advertising material can be examined in the future.

    View record details
  • 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.

    View record details
  • 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.

    View record details
  • "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.

    View record details
  • Dynamic response of rotationally periodic structures : thesis submitted in fulfillment of the degree of Doctor of Philosophy in Engineering, Massey University, School of Engineering and Technology, February 2014

    Mubarak, Rana Noman (2014)

    Doctoral thesis
    Massey University

    Due to their structural dynamics, rotationally periodic structures (RPS) have always been an area of interest for engineers and scientists. RPS is found in almost all industries and could be as large as jet turbines to as small as hard disk drives. We come across with RPS on daily routine like washing machine tub, small gears in home appliances and brakes in automobile etc. With such an influence in our life, an RPS dynamic response to the environment is crucial to keep them working and hence is the focus of the thesis. The research involves three major responses on rotationally periodic structures (RPS) namely vibration, thermal and shock. Hard disk drives and integrally bladed rotors (IBR) has been selected as research models. On vibratory response in rotationally periodic structures, effects on structural designs and free vibrations of integrated bladed rotor (IBR) have been investigated in this research. The migration of natural frequencies is characterized through parametric studies considering changes in blade angle and blade thickness of an underlying uniform axis-symmetric rotor. Recurring coupled repeated doublet modes, defined as replica modes, have been observed in this study by characterizing blade vibrations in-phase or out-of-phase to disk vibrations. Veering and clustering of replica modes’ natural frequencies are observed with respect to the blade design parameters. Existence of replica modes has been verified via experimental studies. Fourier content for the low frequency replica component is found to be sensitive and tuneable to blade angle design. For the thermal response of RPS, structural thermal analysis of spindle disk assembly used in hard disk drives (HDDs) was adopted. With the view toward understanding the underlying physics and to minimize the corresponding repeatable run-out (RRO) of track following position error signal (PES) in high track per inch (TPI) magnetic disk drives, analytical representations of thermal expansion mismatch between disk and spindle hub structure formulated in form of operators and finite element analysis (FEA) are employed. Parametric studies with analysis taken at different operational temperatures suggested that RRO can be minimized significantly when location of spindle notch is properly located. RRO harmonics resulted from the thermal expansion mismatch and structure misalignments are studied and concluded with simple algebraic expression related to number of fasteners used in the disk-spindle assembly. On shock response of RPS, head gimbal assembly (HGA) in HDD was analysed. Experimental observation of de-bonding phenomena between head gimbal assembly (HGA) and suspension for a commercial 3.5-inch enterprise HDD under non-operational 250G shock test was performed. In this research the experimental observation and numerical finite element studies were conducted to understand the effect on the mechanical failure of HGA when it is subjected to non-operational shock in the parked position on the ramp. Different design modifications were adapted to withstand shock waves. It was observed that by changing flexure angle in HGA, shock stress can be reduced. FEA simulation results have been presented to verify the findings. The research findings in this thesis can be implemented in the industry where RPS has been widely used, as for example the new replica modes discovery in bladed rotors can also been applied on small scales like as on hard drive, where no. of blades can be replaced by no. of fasteners and the spinning hard drive will be benefited by studying its vibrations with concentration on replica modes. Furthermore, the serendipitous finding of HDD platters expansion under thermal stress can be beneficial in actually storing more data per inch as it has been recently used in TAMR (thermally assisted magnetic recording) technology. Gears, brakes, washing machines to name a few can get supported from the findings in the thesis where controlling vibrations, shock and heat is crucial.

    View record details
  • 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.

    View record details
  • 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.

    View record details
  • 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.

    View record details
  • Point process models for diurnal variation rainfall data : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Statistics at Massey University, Albany (Auckland), New Zealand

    Ismail, Norazlina binti (2014)

    Doctoral thesis
    Massey University

    The theoretical basis of the point process rainfall models were developed for midlatitude rainfall that have different temporal characteristics from the tropical rainfall. The diurnal cycle, a prominent feature in the tropical rainfall, is not represented in the point process models. An extension of the point process models were developed to address the diurnal variation in rainfall. An observed indicator of the rainfall, X is added to the point process models. Two point process models, Poisson white noise (PWN) and Neyman-Scott white noise (NSWN) model were used as the main rainfall event, Y . The rainfall is modelled assuming two cases for the variable X, independent and dependent. Bernoulli trials with Markov dependence are used for the dependent assumption. To allow the model to display the diurnal variation and correlation between hours, the model was fitted to monthly rain- fall data by using the properties of two hour blocks for each month of the year. However, the main point process models were assumed the same for each of the 12 blocks, thus having only one set of point process parameters for the models for each month. There are 12 rainfall occurrence parameters and 12 Markov dependence parameters, one for each block. A total of six models were fitted to the hourly rainfall data from 1974 to 2008 taken from a rain site in Empangan Genting Klang, Malaysia. The PWN and NSWN models with X were first fitted with the assumption that the rainfall indicators are independent between the hours within the two hour block. Simulation studies showed the model does not fit the moments properties adequently. The models were then modified based on a dependence assumption between the hours within the two hour block. These models are known as the Markov X-PWN and Markov X-NSWN models. Both models improve the fit of the moment properties. However, having only one point process model to represent the rainfall events for Malaysia rainfall data was not sufficient. Since tropical rainfall consists of two types of rain, convective and stratiform, the PWN and Markov X-NSWN model were superposed to represent the two types of rainfall. A simple method by assuming non-homogenous PWN process for every two hour block did not fit well the daily diurnal variation. A comparison between the six models show that the superposed PWN and Markov X-NSWN model improved the fitting of mean, variance and autocorrelation. The superposed model was then simplified to an 8-block model to reduce the number of parameters. This modification to the point process models succeeded in describing the diurnal variation in the rainfall, but some of the models were not able to fit other properties that were not included in the parameter estimation process such as the extreme values.

    View record details
  • 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.

    View record details
  • 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.

    View record details
  • 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.

    View record details