967 results for Doctoral, 2016

  • The chemistry of the bioluminescence of the New Zealand Glow-Worm

    Watkins, Oliver (2016)

    Doctoral thesis
    University of Otago

    The aim of the research described in this thesis was to discover the luciferin responsible for bioluminescence in the New Zealand glow-worm (GW) Arachnocampa luminosa. This work was done in partnership with Dr Miriam Sharpe whose focus was to elucidate the luciferase. In order to determine the structure of the GW luciferin, the luciferin had to be isolated from the GW and the structure elucidated via characterisation. However, luciferin purifications pose a unique isolation challenge, combining the difficulties of isolating material from source organisms, working with unstable materials, and working with enzymatic assays. Furthermore characterisation of luciferins is often difficult due to the small amounts that can be isolated and because luciferins are often highly unstable. Previous work on luciferins in other organisms and on the GW luciferin is reveiwed in Chapter 1. Chapter 1 also reviews the general literature on bioluminescence but with a focus on luciferins rather than luciferases. Chapters 2 describes the collection of Arachnocampa luminosa from the wild, and the development of a GW bioluminescence assay that enabled GW luminescent molecules to be detected. This assay enabled the detection of two different types of luminescence: P type luminescence and L type luminescence. Chapter 3 describes the separation of glow-worm lysates by reverse phase chromatography and how the luminescence assay was used to trace GW luminescent molecules through the purification process. This led to the discovery of two glow-worm luciferin precursors: tyrosine and xanthurenic acid that gave P type luminescence with the GW bioluminescence assay. The compound responsible for the L type luminescence was separated away from the compounds responsible for P type luminescence but could not be isolated. The compound responsible for L type luminescence was found to co-elute with tryptophan and is thought to be the GW luciferin. Chapter 4 describes how commercial samples of these precursors (xanthurenic acid and tyrosine), along with GW enzymes, were used to produce a compound (LRPA) that could be characterised by MS and 1H NMR. A solution of LRPA was found to produce L type luminescence with the luminescence assay showing LRPA to be either the GW luciferin or a closely related compound. Chapter 5 then describes the synthesis of two molecules (N-carbamyl tyrosine and phenol-O-carbamyl tyrosine) that were candidates for a compound that co-eluted with tyrosine. Neither of these molecules matched the unknown candidate which was later found to be 3-OH kynurenine. The research on the New Zealand glow-worm described in this thesis required intensive use of LC-MS techniques. However the research was often slowed by a shortage of glow-worms. These techniques were therefore used to investigate another New Zealand natural products problem involving insect metabolites; the origins of tutin, hyenanchin and the tutin glucosides found in New Zealand toxic honeys. Chapter 6 therefore describes a quantitative LC-MS study that shows that these compounds are of plant, not insect origin and that tutu may use glycosylation to aid in tutu transport.

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  • The Numerical Initial Boundary Value Problem for the Generalised Conformal Field Equations in General Relativity

    Stevens, Christopher Zane (2016)

    Doctoral thesis
    University of Otago

    The purpose of this work is to develop for the first time a general framework for the Initial Boundary Value Problem (IBVP) of the Generalised Conformal Field Equations (GCFE). At present the only investigation toward obtaining such a framework was given in the mid 90's by Friedrich at an analytical level and is only valid for Anti-de Sitter space-time. There have so far been no numerical explorations into the validity of building such a framework. The GCFE system is derived in the space-spinor formalism and Newman and Penrose's eth-calculus is imposed to obtain proper spin-weighted equations. These are then rigorously tested both analytically and numerically to confirm their correctness. The global structure of the Schwarzschild, Schwarzschild-de Sitter and Schwarzschild-Anti-de Sitter space-times are numerically reproduced from an IVP and for the first time, numerical simulations that incorporate both the singularity and the conformal boundary are presented. A framework for the IBVP is then given, where the boundaries are chosen as arbitrary time-like conformal geodesics and where the constraints propagate on (at least) the numerical level. The full generality of the framework is verified numerically for gravitational perturbations of Minkowski and Schwarzschild space-times. A spin-frame adapted to the geometry of future null infinity is developed and the expressions for the Bondi-mass and the Bondi-time given by Penrose and Rindler are generalised. The Bondi-mass is found to equate to the Schwarzschild-mass for the standard Schwarzschild space-time and the famous Bondi-Sachs mass loss is reproduced for the gravitationally perturbed case.

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  • What Happened at the End of Lapita: Lapita to Post-Lapita Pottery Transition in West New Britain, Papua New Guinea

    Wu, Pei-hua (2016)

    Doctoral thesis
    University of Otago

    This study presents a detailed Lapita to Post-Lapita sequence/transition with chronology at particular sites in west New Britain, through the medium of pottery analysis of style and production. The data allow me to address the research questions: (1) the cultural change that happened toward the end of Lapita, and (2) the issue of cultural continuity/discontinuity between the Lapita and Post-Lapita periods. This study identified a cultural change with greater break down and regionalization/diversification of the Lapita societies in the Late Lapita phase around and after 2750/2700 BP. This study also identified detailed pottery characterization, production, and provenance in west New Britain through compositional analysis, using a scanning electron microscope (SEM), which helps in understanding the interactions in the Lapita and Post-Lapita periods between west New Britain and other regions. In addition, this study identified a distinctive vessel form of double spouted pots of Lapita pottery that might originate from Island Southeast Asia, and demonstrates that after Lapita peoples had reached the Bismarcks, they maintained contact with homeland communities in Island Southeast Asia, and the double spouted pots were later introduced to the Bismarcks through interactions.

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  • Motherhood and Family Law

    Mackenzie, Fiona Amy (2016)

    Doctoral thesis
    University of Otago

    Throughout the broad sweep of history and related disciplines, including the law, can be found instruction with respect to the issue of motherhood. In one sense, it transcends culture; in another, it is a cultural construct. It is imbued with gender specificity and is profoundly important to children. This thesis explores motherhood’s relationship with family law and seeks to illustrate how, through uneasy tensions over time, it may have been compromised in modern child care law in New Zealand. It discusses whether parenting law should continue to adopt a gender neutral approach or whether, in considering a child’s welfare and best interests, there may be a case for greater recognition and restoration of gendered parenting relationships and perhaps, therefore, a repeal of s4(3) of the Care of Children Act 2004.

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  • Lapita Plants, People and Pigs

    Tromp, Monica (2016)

    Doctoral thesis
    University of Otago

    The Lapita cultural complex is associated with the Austronesian expansion out of Island Southeast Asia beginning approximately 3,500 BP. Sites associated with this archaeological culture have been found from the coast of New Guinea in Near Oceania and out past the Solomon Islands into Remote Oceania as far south as New Caledonia and as far east as Samoa by 2,700 BP. Major components of this culture include the commensal animals and horticultural plants that were transported with them as a portable subsistence economy during their voyaging. The commensal animal component of this package is reasonably well established, but the plant portion is less clear. This is primarily due to the scarcity of plant macro remains that have been found from archaeological sites and the lack of specificity of actual foods consumed in stable isotope analyses of archaeological human and animal bone. One direct way to explore the dietary plant component is to identify micro particles of plants (microfossils) that have been trapped within calcified plaque (dental calculus). The primary aim of this thesis is to examine the relationship between Lapita and immediately post-Lapita people and plants. The secondary aim is to examine whether human and commensal pig plant diets are similar and if it is possible to use pig diet as a proxy for human diet when human remains are not available for analysis. To address these aims, microfossils were extracted from human and pig dental calculus from four different sites: the SAC site on Watom Island, East New Britain Province, Papua New Guinea; Teouma on Efate Island, and Vao and Uripiv islands off the coast of northeast Malakula in Vanuatu. The samples were examined using a combination of light microscopy and scanning electron microscopy. All of the samples analysed date between Lapita (~3000 cal BP) and post-Lapita (~2500 cal BP) periods. These sites allow for a comparison of 1) an initial colonizing population (Teouma) and later populations (Watom, Uripiv and Vao), 2) Near Oceanic (Watom) and Remote Oceanic (Teouma, Uripiv and Vao) sites and 3) the wild versus cultivated plant components of their diets. The results show a much more diverse plant diet than has previously been shown. The importance of indigenous trees and shrubs to both Lapita and post-Lapita people analysed from all sites has been demonstrated in this study. Novel results include the first instance of banana seed phytoliths outside of the Bismarck Archipelago and an early introduction of Dioscorea esculenta to Vanuatu. The appearance of these non-indigenous plants at Teouma provides support for the concept of a “transported landscape”. However, the majority of identified plants were indigenous tree crops that suggest Lapita colonists were at least partly reliant on the forest resources that already existed on the islands they inhabited. This study represents the first direct plant evidence for Lapita and immediately post-Lapita diet of humans and pigs from this region.

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  • Improving Clustering Methods By Exploiting Richness Of Text Data

    Wahid, Abdul (2016)

    Doctoral thesis
    Victoria University of Wellington

    Clustering is an unsupervised machine learning technique, which involves discovering different clusters (groups) of similar objects in unlabeled data and is generally considered to be a NP hard problem. Clustering methods are widely used in a verity of disciplines for analyzing different types of data, and a small improvement in clustering method can cause a ripple effect in advancing research of multiple fields. Clustering any type of data is challenging and there are many open research questions. The clustering problem is exacerbated in the case of text data because of the additional challenges such as issues in capturing semantics of a document, handling rich features of text data and dealing with the well known problem of the curse of dimensionality. In this thesis, we investigate the limitations of existing text clustering methods and address these limitations by providing five new text clustering methods--Query Sense Clustering (QSC), Dirichlet Weighted K-means (DWKM), Multi-View Multi-Objective Evolutionary Algorithm (MMOEA), Multi-objective Document Clustering (MDC) and Multi-Objective Multi-View Ensemble Clustering (MOMVEC). These five new clustering methods showed that the use of rich features in text clustering methods could outperform the existing state-of-the-art text clustering methods. The first new text clustering method QSC exploits user queries (one of the rich features in text data) to generate better quality clusters and cluster labels. The second text clustering method DWKM uses probability based weighting scheme to formulate a semantically weighted distance measure to improve the clustering results. The third text clustering method MMOEA is based on a multi-objective evolutionary algorithm. MMOEA exploits rich features to generate a diverse set of candidate clustering solutions, and forms a better clustering solution using a cluster-oriented approach. The fourth and the fifth text clustering method MDC and MOMVEC address the limitations of MMOEA. MDC and MOMVEC differ in terms of the implementation of their multi-objective evolutionary approaches. All five methods are compared with existing state-of-the-art methods. The results of the comparisons show that the newly developed text clustering methods out-perform existing methods by achieving up to 16\% improvement for some comparisons. In general, almost all newly developed clustering algorithms showed statistically significant improvements over other existing methods. The key ideas of the thesis highlight that exploiting user queries improves Search Result Clustering(SRC); utilizing rich features in weighting schemes and distance measures improves soft subspace clustering; utilizing multiple views and a multi-objective cluster oriented method improves clustering ensemble methods; and better evolutionary operators and objective functions improve multi-objective evolutionary clustering ensemble methods. The new text clustering methods introduced in this thesis can be widely applied in various domains that involve analysis of text data. The contributions of this thesis which include five new text clustering methods, will not only help researchers in the data mining field but also to help a wide range of researchers in other fields.

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  • Assessing Learning, Breathing and Treatment of Respiratory Obstruction During Sleep in School Children: The ALBATROSS Study

    Maessen, Sarah Elizabeth (2016)

    Doctoral thesis
    University of Otago

    Introduction: Children with enlarged tonsils and/or adenoids are at risk for sleep disordered breathing (SDB), a common disorder in childhood characterised by snoring, choking, and pauses in breathing during sleep. SDB has been associated with a number of adverse effects on aspects of daytime functioning, including quality of life, behaviour, general cognitive functioning and memory. It has been documented that these difficulties can have a negative effect on school performance, but it is not known how children with SDB may differ from day to day in their school performance, or how their academic growth from week to week may be different from children without SDB. Furthermore, treatment of SDB by removing obstructive tonsillar and adenoid tissues can result in improvements in SDB symptoms, quality of life, and behaviour, but it is unclear whether this extends to school achievement. Previous research has used measures of academic performance such as parent and teacher report or standardised achievement tests. These kinds of measurements are not able to provide information about growth in academic achievement, and are not designed to be sensitive to treatment effects. The current research is a case series examining children on the waiting list for adenotonsillectomy (AT), a high risk group for SDB, using a multimethod-multi-informant approach to assessment. These children were assessed in domains where changes have previously been demonstrated after AT, i.e., SDB symptoms, quality of life and behaviour, as well as in academic performance, where results of previous research have been more equivocal. Methods previously used in SDB research to assess academic performance were used alongside alternative indicators of progress in literacy and numeracy. These measures were informed by evidence-based measurement approaches used to evaluate academic intervention, and were selected to probe skills specific to each child’s school year. This approach has previously demonstrated sensitivity to treatment effects in interventions for neurodevelopmental disorders. Methods: 20 case children aged 3-11 years were recruited from the waiting list for adenotonsillectomy at Dunedin Public Hospital. 19 of these children were matched to controls for age, sex, and school year, including academic performance where possible. 44% of participants were male, and 46% were preschool aged. All children were described in terms of their symptoms of SDB using parent ratings on the Pediatric Sleep Questionnaire, quality of life using the OSA-18 and Pediatric Quality of Life Inventory, behaviour using the SWAN rating scale and BASC-2 BESS , general cognition using the WPPSI-III and WISC-IV, and academic performance at matched time points both before surgery and at a follow up 7 months after surgery. In addition, an AHI was derived from home-based sleep studies conducted both before surgery and at a 3 month follow up. Academic performance was measured using parent and teacher judgements in relation to National Standards, performance on a standardised achievement test (WIAT-II Australian), and using the developmentally appropriate literacy and numeracy measures that were expected to be sensitive to changes across the study. The literacy and numeracy indicators were administered twice, one week apart, at each time point: twice before surgery (pre-‘surgery’), twice at the 3 month follow up (post-‘surgery’), and twice again at the 7 month follow up. These assessment points are similar to the timeline of previous SDB research. The current research takes both visual and statistical approaches to data analysis, allowing for examination of individual case-control pairs and within-subjects changes as well as group-level statistics. Results: At pre-‘surgery’, case children on average had more parent-reported SDB symptoms than matched controls (p = .001). This pattern was confirmed by AHI from overnight sleep studies indicating that the majority of case participants had clinically significant levels of SDB. As well as increased SDB symptoms, case children on average had poorer quality of life (range p = .001 - .032), behavioural and emotional functioning (p = .020), and memory (p = .001) than matched controls according to parent ratings. Teacher ratings did not suggest elevated levels of behavioural or emotional difficulties for either cases or controls and did not differ between groups, and mean general cognitive functioning scores were also similar between the groups. Typically used measures of academic performance, parent and teacher report and standardised achievement test scores, did not differ on average between case and control children, although case participants’ scores on the WIAT-II mathematics composite score were in the ‘low-average’ range compared to norms. Comparisons of literacy and numeracy indicators between the two pre-‘surgery’ sessions suggested that in general, case children appeared to have more consistent performance than controls from week-to-week, but less growth in these skills. When looking at mean performance on the tasks at pre-‘surgery’, several control children were outperforming their matched case participant, but there was a lot of individual variation in scores. After surgery, case children had improved parent ratings of SDB symptoms (p = .001), quality of life (range p = .001 - .023), behavioural and emotional functioning (p = .008), and memory (p = .014). With the exception of SDB symptoms and memory difficulties, which remained elevated for case children in comparison to matched controls, case and control children no longer differed statistically for mean scores in any other domain of daytime functioning. Teacher ratings of reading in relation to National Standards improved for case children (p = .011), but no other typically used measures of school performance changed notably following surgery. Improvements in scores on the literacy and numeracy indicators suggested different patterns of growth for different academic domains and age groups. For preschoolers, case children showed evidence of linear growth in an early literacy composite that was steeper than for control children on average (p = .008). However, improvement in early numeracy scores suggesting growth in these skills did not differ between case and control participants on average. Year 1 and 2 case participants showed considerable growth in a phoneme segmentation fluency task that was not observed for their matched controls, but there were no clear patterns for any other literacy or numeracy tasks. Children in Years 3 to 5 had improvements in literacy tasks that for some participants were greater than their matched controls, but did not appear to improve in numeracy. Year 6 and 7 students, in contrast, demonstrated evidence of growth in numeracy tasks, but most did not improve in literacy tasks. Conclusions: This research is consistent with previous studies reporting that children with SDB are at risk for poor academic performance or growth. The literacy and numeracy indicators used in the current research provided information about academic performance in these children beyond what could be ascertained from more conventionally used measures. This finding suggests that these more sensitive measures of academic growth have potential for evaluating effects of SDB treatment on academic performance in a larger group of children. The current study has clearly demonstrated that children who are undergoing surgery for removal of tonsils and adenoids in Dunedin are likely to have more symptoms of SDB and related negative effects on daytime functioning when compared to similar children in the community. It also provides preliminary evidence that treatment of SDB in early childhood may help to improve learning trajectories in literacy skills, supporting existing evidence for early identification and intervention for SDB. Many children are affected by health problems other than SDB or behavioural difficulties that have been associated with poorer school performance. The literacy and numeracy indicators used in the current research show promise for assessing the effects of surgical intervention for SDB, and therefore have the potential to explore the effects that treatment of other disorders that can affect school performance, such as otitis media (glue ear) or ADHD, could have on academic achievement.

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  • Palaeomagnetic secular variation recorded by lavas from the Taupo Volcanic Zone, New Zealand

    Greve, Annika (2016)

    Doctoral thesis
    Victoria University of Wellington

    In order to understand the origin, temporal behaviour and spatial characteristics of Earth’s magnetic field, globally distributed records of the palaeomagnetic direction and absolute palaeointensity are required. However a paucity of data from the southern hemisphere significantly limits the resolution of global field models, particularly on short time-scales. In this thesis new, high quality palaeomagnetic data from volcanic materials sampled within the Taupo Volcanic Zone, New Zealand are presented, with a focus on the Tongariro and Okataina Volcanic Centre. New palaeomagnetic directions were obtained from 19 andesitic or rhyolitic lavas, of which 10 also produced successful palaeointensity results. Palaeointensity experiments were conducted using a combination of traditional Thellier-type thermal, and microwave techniques. Detailed magneto-mineralogical investigations carried out alongside these experiments helped to characterise the primary remanence carriers and to justify the reliability of the results. The study also revises the age controls and results from earlier palaeomagnetic studies on Holocene volcanic materials from the area. All new or revised data are summarized into a new data compilation for New Zealand, which includes 24 directions and ten palaeointensities dated between 1886 AD and 15,000 yrs BP. The new directional data reproduces the features of the most recently published continuous record from Lake Mavora (Fiordland, New Zealand), although with directions ranging in their extremes from 321° (west) to 26° (east) declination and -82 to -49° in inclination, the discrete dataset describes somewhat larger amplitude swings. With few exceptions, the new palaeointensity dataset describes a steady increase in the palaeointensity throughout the Holocene, from 37.0 ± 5.7 μT obtained from a pre-8 ka lava to 70.6 ± 4.1 μT from the youngest (≤ 500 yrs BP) flows sampled. A similar trend is also predicted by the latest global field model pfm9k. Furthermore, the data falls within the range of palaeointensity variation suggested by the Mavora record. The dataset roughly agrees with a global VADM reconstruction in the early Holocene (> 5000 yrs BP), but yields values significantly above the global trend in the late Holocene (< 1000 yrs BP) which supports the presence of significant non-dipolar components over the SW Pacific region in the time period, visible in global field models and from continuous PSV records. A comparison of the directional records with the Mavora Curve provided refinement of age estimates of five lava flows from the Tongariro Volcanic Centre, from uncertainties in the range of 2-3000 years. The new palaeomagnetic emplacement age estimates for these flows have age brackets as short as 500 years and thus highlight different phases of the young cone building eruptive activity on Ruapehu volcano.

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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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  • Parasite Ecology and the Conservation Biology of Black Rhinoceros (Diceros bicornis)

    Stringer, Andrew Paul (2016)

    Doctoral thesis
    Victoria University of Wellington

    This thesis combines investigations of parasite ecology and rhinoceros conservation biology to advance our understanding and management of the host-parasite relationship for the critically endangered black rhinoceros (Diceros bicornis). My central aim was to determine the key influences on parasite abundance within black rhinoceros, investigate the effects of parasitism on black rhinoceros and how they can be measured, and to provide a balanced summary of the advantages and disadvantages of interventions to control parasites within threatened host species. Two intestinal helminth parasites were the primary focus of this study; the strongyle nematodes and an Anoplocephala sp. tapeworm. The non-invasive assessment of parasite abundance within black rhinoceros is challenging due to the rhinoceros’s elusive nature and rarity. Hence, protocols for faecal egg counts (FECs) where defecation could not be observed were tested. This included testing for the impacts of time since defecation on FECs, and whether sampling location within a bolus influenced FECs. Also, the optimum sample size needed to reliably capture the variation in parasite abundance on a population level was estimated. To identify the key influences on parasite abundance, the black rhinoceros meta-population in South Africa presented an extraordinary and fortuitous research opportunity. Translocation and reintroduction have created multiple populations from the same two source populations, providing a variety of comparable populations with the same host-parasite relationship. I applied my population-level faecal sampling and egg count protocol to collect 160 samples from 18 black rhinoceros populations over two summer sampling periods between 2010 and 2012. I test hypotheses for the influence of a variety of ecological and abiotic factors on parasite abundance. To test for the influence of individual-level host characteristics on parasite abundance, such as age and sex, I collected rectal faecal samples at the translocation of 39 black rhinoceros. At that time I also investigated the influence of body condition on a variety of measures of host resources, such as the size of sexually selected characteristics. Finally I developed a logical and robust approach to debate whether parasites of threatened host species should be controlled. For faecal egg counts, samples taken from the centre of faecal boluses did not change significantly up to six hours after defecation. The only factor which significantly affected the size of confidence intervals of the mean parasite abundance for a host population for both parasite groups was the level of parasite aggregation. The accuracy of estimates of mean parasite abundance increased with increasing sample size, with >9 samples having little further effect on accuracy. As host defecation no longer needs to be observed the efficiency of fieldwork for studies investigating elusive host species is greatly increased. On a population level, host density was the leading model explaining the abundance of both a directly and an indirectly transmitted parasite. For instance, doubling host density led to a 47% rise in strongyle parasite abundance. I found no support for competing hypotheses, such as climate-related variables, that were thought to affect the abundance of free-living stages of macroparasites. This result will be useful to conservationists as it will allow them to predict where parasite abundance will be greatest and may also reveal potential avenues for parasite control. On an individual level, younger individuals may have harboured higher levels of parasitism (p = 0.07). This result would be widely supported by the literature, but a larger host age range is needed to verify the result. I identified four sexual dimorphisms, with anterior horn volume and circumference, and body size, all showing a sex difference in both the slope and intercept of regression lines. Although sexually selected traits are implicated as most vulnerable to parasite impacts, I did not find an influence of parasite abundance on the size of these potentially sexually-selected characteristics or other measures of body condition. This may be because of numerous different factors affecting host resources, of which the parasite groups studied are a relatively small proportion. Parasites can be an important cause of population decline in threatened species. However, the conservation of potentially threatened parasites within host species is rarely considered. Here, I debated the potential benefits and pitfalls of parasite control to help identify the principles behind parasite control within threatened species. I rank 11 identified different types of parasite control by their potentially detrimental effects on host populations and ecosystems. I conclude that as the risk a parasite poses to host extinction increases, so does the justification for using parasite control methods with potentially detrimental effects. Also, the extinction risk of the parasite should determine the need for dedicated parasite conservation programs. These principles may be predominantly intuitive, but there are a number of examples in the literature where they have not been used, such as the treatment of parasites with low levels of virulence in host species of ‘least concern’. The principles provide a framework for the adaptive implementation of parasite control strategies in conservation-reliant species, like rhinoceros. I embarked on the first multi-population and comparative study of host-parasite relationships in the critically endangered black rhinoceros. This was made possible by empirically testing and refining field sampling protocols to overcome concerns about sample identification, number, and age. Through these well-developed, efficient sampling methodologies I was able to determine that host density was the main influence on parasite abundance within black rhinoceros on a population level – a result not previously proven for macroparasites. Influences on individual level variation need further investigation. In particular genetic factors, such as inbreeding, were not researched as part of this study. I successfully identified a number of sexual dimorphisms, but found no evidence that they were influenced by individual parasite abundance. Finally I use a targeted review of the literature to propose some principles behind whether parasites should be controlled within threatened host species. These principles should allow conservation managers to focus resources on those situations where parasite control is needed, and also help conservation managers avoid the potentially detrimental effects of parasite control. In these ways this thesis has advanced the study and understanding of parasites, their ecology, and their relationship to conservation-reliant hosts.

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  • The role of free clinics in primary health care for vulnerable people: Policy and theory development based on empirical analyses of the free clinic in Dunedin, New Zealand.

    Loh, Lik Wei (2016)

    Doctoral thesis
    University of Otago

    A clinic providing primary health care services free-of-charge to all its enrolled patients opened in January 2010 in Dunedin. It was staffed by volunteer clinicians, many of whom were motivated by their Christian faith. Its patients were socially vulnerable, and had complex health needs. This setting provided an opportunity for a ‘natural experiment’, whose aim was to study the delivery, context and effects of free primary health care, and the socio-demographic and clinical characteristics of the target population using such services. The expectation was that the removal of the cost barrier would enable vulnerable patients to better access comprehensive health care. Since capturing the phenomenon (free primary health care provision) and its context were fundamental to understanding the Free Clinic, the case study methodology was used to examine the application of the phenomenon, as part of developing theory around the place of free general practice care in New Zealand. This case study comprised four component studies. A questionnaire-based study compared the socio-demographic characteristics of patients at the Free Clinic and those at a nearby fee-charging traditional clinic. A nested case study examined the nature of Free Clinic patients' diverse needs, the Free Clinic's model of care, and whether the model was a good match to patients' needs. An audit of electronic records was performed to profile the reasons Free Clinic patients consulted their general practitioner. A controlled before-and-after study of Free Clinic patients matched to other Dunedin residents by propensity scores assessed the effect of the Free Clinic on hospital use by its patients. These studies combined qualitative and quantitative research methods. Free Clinic patients were on average younger and more likely to be Māori than the wider Dunedin population, and more likely to reside in highly deprived areas, and report high levels of individual-level deprivation. Despite their poorer self-reported health status and greater levels of multimorbidity, Free Clinic patients were likely to report having unmet needs for medical and dental services, and not being able to collect prescription items because of cost. When asked to comment on the Free Clinic’s model of care, patients placed value on the “friendly” and non-judgmental nature of the care they received, and being able to simply drop-in without an appointment to receive support for diverse health and social concerns. Free Clinic patients brought fewer than average ‘reasons-for-visit’, and tended to consult for administrative and repeat prescription requests. Follow-up of Free Clinic patients for five years after the clinic’s opening failed to reveal any significant decrease in their hospital use. Compared with matched controls, Free Clinic patients visited the emergency department more frequently after the clinic opened than before it opened. Beyond access to health care, patients such as those attending the Free Clinic need access to the social conditions and resources that promote health. Beyond a model of care sympathetic to their needs, a protracted period of making small, incremental efforts is necessary before gains in health may be reaped. Given the limitations of the current primary health care funding and service delivery framework, the establishment of designated ‘fit for purpose’ clinics for vulnerable populations is necessary. Further research is needed to identify primary health care patients with significant unmet health needs, and to find an appropriate measure other than hospital use to evaluate policy interventions aimed at improving primary health care access.

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  • An Analysis of the Extent, Purposes, and Outcomes of Ski Areas’ Environmental Communications

    Spector, Samuel (2016)

    Doctoral thesis
    University of Otago

    This qualitative study investigates the extent, purposes, and outcomes of environmental communications (hereafter ECs) produced by ski areas on New Zealand’s South Island. Researchers have examined why ski areas participate in environmental initiatives, but there is a dearth of knowledge regarding why communications about these environmental efforts are published. Skiing exerts significant environmental impacts but is simultaneously reliant on particular environmental conditions. The ECs of ski areas, as one way in which reactions to these impacts and vulnerabilities are communicated, warrant study. In addition to analysing the ski areas’ ECs, semi-structured, in-depth interviews with insiders from the ski areas and with skiers were used to investigate the extent, purposes, and outcomes of the ECs. Legitimacy theory, which postulates that organisations must demonstrate they embrace societal values in order to remain profitable, is utilised as a theoretical lens for approaching this topic. Thematic data analysis of the ECs, interviews with ski area managers, and interviews with skiers was conducted using an inductive, interpretive approach which allowed for the periodic revision of coding themes as they emerged throughout the analysis process. The following themes were identified from interviews with ski area insiders and analysis of the ski areas’ ECs: a focus on local, tangible environmental issues, numerous constraints restricting the production and dissemination of ECs, a range of impetuses driving engagement in EC, EC as interwoven with developing and maintaining social legitimacy, and the outcomes of EC being seen as distinctly varied. As predicted by the insiders, analysis of interviews with skiers found they were unaware of ECs not related to recycling; and, due to the perceived lack of prominence of the ECs, skiers did not express sentiments of ‘green fatigue.’ As also anticipated by the insiders, skiers were unwilling to make destination choices or restrict skiing based upon the ski areas’ environmental performance. Skiers believed the ECs are published because there is no disadvantage to doing so and a competitive advantage amongst a small audience may result, they accepted the accuracy and legitimacy of the ECs, and they perceived skiing to be a relatively benign use of nature. Follow-up interviews with ski area insiders allowed discussion of key points of interest from the interviews with skiers. During the follow-up interviews the insiders contrasted local skiers, ski area staff, and the Department of Conservation with ‘holiday skiers’ (the latter being seen as not prioritising environmental performance) to explain why ECs continue to be published despite skiers’ lack of awareness of those communications and unwillingness to make destination choices based on such factors. The insiders viewed skiers’ lack of ‘green fatigue’ as stemming from the ski areas’ restrained approach to using ECs, the small size of the ski areas, and the ‘clean and green’ image attached to New Zealand. In addition to the formal thematic analysis, two discussion points are critically examined. First, the thesis offers a critique of EC due to the complexities inherent in delineating the concept. These complexities arose both in terms of demarcating the ‘environmental’ aspect of EC (e.g. non-environmental factors, such as a ski area being family owned, being salient in shaping how the ski area’s environmental impact is viewed) in addition to the ‘communication’ aspect of the concept (e.g. communications arising from skiers rather than the ski area via dialogue-enabled mediums such as social media potentially influencing a ski area’s pro-environmental image). Second, there is a lack of attention afforded ski tourists’ transportation when envisioning an environmentally responsible skier or ski area. Interviews with ski area insiders indicated they view skiers’ non-local transport as outside their purview. Skiers likewise did not deem themselves or the ski areas as responsible for addressing transport-related impacts. As climate change poses one of the greatest threats to tourism in general, and skiing specifically, the lack of substantive efforts to address tourists’ transportation is egregious.

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  • A Discourse Analysis of Self-management for Bipolar Disorder

    Wilson, Lynere Deborah (2016)

    Doctoral thesis
    University of Otago

    In line with a movement across all areas of health concerned with chronic illness, self-management practices have become an important part of what it means to provide contemporary mental health care to people with the psychiatric diagnosis of bipolar disorder. In mental health settings it is a taken-for-granted practice. The aim of this thesis is to use Foucauldian Discourse Analysis to explore how the discursive practices of self-management for bipolar disorder produce particular forms of subjectivity for those understood to have the condition and the implications of this for processes of self-formation. In order to consider how discourse is used to both govern others and govern the self, two sources of text are used for analysis. The first source is the Psychoeducation Manual for Bipolar Disorder (Colom & Vieta, 2006) which details how mental health professionals can teach people with bipolar disorder about their condition in order that they might better manage themselves. The questions guiding the analysis of this text as how discourse constructs bipolar as an object, what subject positions it makes available and what relationship people are expected to have with the object named as bipolar disorder. The second source of text are the transcripts of semi-structured interviews completed with 25 people with bipolar disorder as part of their entry to a clinical trial of psychotherapy and medication management as a means to reduce rates of acute psychiatric assessment and hospitalization. Analysis of these texts is concerned with how discourse is used to govern the self and is developed in a two stage process. The analysis is guided firstly by questions that ask how bipolar disorder is constructed, how is self-management constructed as an object, how is life with bipolar disorder constructed and what discourses are drawn on the process. The second stage of analysis of these texts focuses on the subject positions being made available in self-management discourse. This analysis finds that as an object, bipolar disorder is constructed as both an illness of the brain and an object the produces an unreliable mind such that it is an object that is separate from a person’s sense of self while also being an object that interferes with the mind’s capacity to know itself. This results in persistent tensions to be negotiated within self-management practices such that self-management discourse produces subject positions characterised by dividing practices and contradiction. The discourses of medicine and psychology can be seen to act to tightly regulate how bipolar disorder can be understood which results in all aspects of a person’s self being shaped by the condition they are understood have. These discourses have become the only way a person can legitimately construct a sense of themselves and through the workings of pastoral styles of power relationships psychological discourse can be seen to be used ultimately in the service of medical discourse. With self-management discourse seen as operating on the basis of division and contradiction, this thesis proposes that the nature of the problem in the self-management of bipolar disorder is not the disorder or the person it is understood to inhabit but rather the norms of the self on which contemporary Western society bases its understanding of what it means to be a normal subject. The thesis concludes firstly with two alternate constructions of selfhood; the self as formed through connection and the self as formed through the management of the abject and then with a proposal for an alternate approach to psychoeducation as a particular strategy of self-management discourse for bipolar disorder. The significance of this thesis lies in its use of a Foucauldian methodology to question the assumptions of beneficence understood to drive the promulgation of self-management practices in health care. Its resulting re-evaluation of the nature of the self in the discursive practices of self-management for bipolar disorder and its proposal for an alternate approach to psychoeducation is put forward as a contribution to the project of a contemporary critical psychiatry.

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  • Factors affecting glucose homeostasis in premature neonates

    Salis, Emma (2016)

    Doctoral thesis
    University of Otago

    Introduction After birth rapid metabolic adaptation is required to establish glucose homeostasis.Preterm birth disrupts normal timing of this physiological adaptation putting premature neonates at risk of hypo- and hyperglycaemia. A major barrier to conducting pharmacokinetic studies in neonates is the relatively large volume of blood required by most assays. The use of dried blood spots (DBS) has the potential to enable the use of smaller sample volumes and simplifies processing and handling. However, haematocrit in neonates varies significantly and can affect the accuracy of DBS assays. Insulin and C-peptide are secreted in equimolar amounts from the pancreas. C-peptide can be used as a biomarker for insulin secretion as, unlike insulin, it is not hepatically cleared and has a longer plasma half-life. Urinary C-peptide may give a non-invasive way of measuring insulin production in neonates. The insulin/C-peptide (I/CP) ratio gives an indication of relative insulin clearance in adults but normal ranges have not been reported in neonates. Premature neonates have significantly higher fasting levels of glucagon-like peptide-1 (GLP-1) than adults and are increased even further with feeding. Hyperglycaemia can often occur in extremely premature neonates and is associated with an increase in morbidity and mortality. Insulin resistance is a key issue in preterm neonates and it is thought that hyperglycaemia is a consequence of relative insulin deficiency. Aims The aims of this research were: to investigate the use of a DBS assay for measuring insulin concentrations to improve sampling for pharmacokinetic studies; to describe the relationship between C-peptide and insulin secretion in the neonatal population; to investigate the relationship between feeding, incretin (GLP-1) and insulin secretion in neonates. Finally, to compare these results with neonates treated with insulin for hyperglycaemia to investigate alterations in glucose homeostasis in hyperglycaemic neonates. Methods Blood samples, DBS and urine samples were obtained from euglycaemic and hyperglycaemic insulin-treated preterm neonates admitted into the Dunedin Hospital Neonatal Intensive Care Unit (NICU) for this research project. DBS of varying haematocrit (0.25-0.65) were prepared at three insulin plasma concentrations (10, 25 and 50mU/L) and were analysed for insulin using the method developed by Butter et al (2001). DBS and paired plasma samples were obtained from neonates. Standard addition and direct measurement from the kit standard curve were compared for measurement of urinary C-peptide. Insulin concentrations in plasma, along with C-peptide concentrations in plasma and urine (diluted to 40%) were measured in 20 neonates. Urine volume and time of collection were recorded and used to calculate C-peptide urinary excretion rate (UER) and clearance (Cl). Samples for 102 euglycaemic neonates were obtained from leftover blood from routine tests. Samples were obtained for 10 hyperglycaemic insulin-treated neonates and there were 9 for which additional blood was collected at the same time as the patients’ routine four hourly blood glucose test over a 24-hour period (6 samples). Data were collected from clinical notes for gestational age (GA), postmenstrual age (PMA), postnatal age, birth weight, current weight, birth length, birth head circumference, oral intake, and intravenous fluids at time of samples. Insulin and C-peptide concentrations from the hyperglycaemic insulin-treated neonates were compared with a group of age-matched (PMA 0.05). Direct measurement from kit standards produced a more precise and simple method for determining C-peptide concentration. The mean (SD) C-peptide Cl was 0.309 (0.329) mL/min/kg and UER was 0.0329 (0.0342) pmol/min/kg. Correlations between Cl or UER and gestational age were not significant (p >0.05). No significant correlation was shown between UER or Cl and blood glucose concentration (BGC). Insulin and C-peptide concentrations were elevated in very preterm infants (PMA ≤32 weeks) and decreased as the neonate approached term. Data were natural log normally distributed and linear regression of ln-transformed data was performed. Linear regressions showed that I/CP ratio and insulin/BGC (I/BGC) ratio decreased significantly with increasing PMA (p <32 weeks). C-peptide concentrations were significantly lower in the hyperglycaemic neonates indicating lower insulin production in hyperglycaemic neonates. Treatment with exogenous insulin did not suppress insulin production in these neonates.

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  • Effects of Ocean Acidification, Temperature and Copper on the development of early life stages of the Native Kelp Macrocystis Pyrifera and the Invasive Kelp Undaria Pinnatifida from Southern New Zealand

    Leal Sandoval, Pablo Patricio (2016)

    Doctoral thesis
    University of Otago

    Anthropogenic activities have increased atmospheric CO2 concentrations from pre-industrial concentrations of 280 ppm to current values of 400 ppm. These atmospheric emissions of CO2 are responsible for the ongoing increase in seawater temperature and the reduction of pH in the ocean’ surface, phenomena known as ocean warming (OW) and ocean acidification (OA), respectively. Model-based projections indicate that the global ocean surface temperature will increase by 4°C whereas the pH will decrease from a current 8.10 to 7.74 by 2100. However, these two global events are not occurring in isolation because anthropogenic activities also threatens coastal environments at local levels. For instance, in coastal environments, natural concentrations of copper are low but are increasing due to human industrialization. In addition, the speciation and bioavailability of copper in seawater is highly dependent on seawater chemistry. Therefore, reductions in seawater pH due to OA will increase the toxic, free ionic form of copper in oceans by 20% by the end of the current century. These abiotic changes can have important impacts on marine biota and ecosystems. Fleshy (non-calcifying) macroalgae such as those that belong to the Order Laminariales are important components of coastal environments. Macroalgae, as sessile organisms, are exposed to constant changes in abiotic factors and the community dynamics (e.g., growth and reproduction) depend on their tolerance to stress. Despite their importance, few studies have focused on the effects of OW, OA and/or copper pollution on fleshy macroalgae and even less have focused on their early life stages. Early life stages have been reported to be the most sensitive phase of the macroalgal life cycle to stressors. Therefore, the main purpose of this work was to evaluate the separate and interactive effects of seawater temperature, pH and copper concentration on the development of microscopic stages of the native kelp M. pyrifera and the invasive kelp U. pinnatifida from southern New Zealand. The first result of this work was that, in M. pyrifera, sporogenesis occurred in basal sporophylls (specialized reproductive laminae) as well as in non-reproductive laminae such as pneumatocyst-bearing adult blade and young apical scimitars. The sorus surface area was greater on sporophylls (57%) than in adult blades and young scimitars (25%). Meiospore release was greater in apical scimitars, followed by adult blades and sporophylls. However, germination of meiospores from different laminae was not significantly different, indicating that meiospores produced in all types of fertile laminae were equally viable. The first climate change-related experiment consisted of monitoring meiospore development of M. pyrifera and U. pinnatifida cultured under four seawater pH treatments (pH 7.20, extreme OA predicted for 2300; pH 7.65, OA predicted for 2100; pH 8.01, ambient pH; and pH 8.40, pre-industrial pH) for 15 days. Reduced seawater pH (7.20 and 7.65) had no effects on meiospore germination but had positive effects on germling growth rates and gametophyte size of both species compared to higher pH (8.01 and 8.40). Gametophyte sex ratio was biased towards females under all pH treatments. Germling growth rate under OA was significantly higher in M. pyrifera compared to U. pinnatifida but gametophyte development was equal for both kelps under all seawater pH treatments, indicating that the microscopic stages of the native M. pyrifera and the invasive U. pinnatifida will respond similarly to OA. The second experiment climate change-related experiment consisted of monitoring meiospore development of M. pyrifera and U. pinnatifida cultured under four seawater pH treatments (pH 7.20, 7.65, 8.03, and 8.40) and two temperature treatments (12°C, ambient temperature; and 16°C, OW predicted for 2100) for 15 days. Reduced seawater pH and elevated temperature had no effects on meiospore development and positive effects on germling growth rates and gametophyte size of both species compared to higher pH (8.01 and 8.40) and lower temperature (12°C), whereas gametophyte sex ratio was not affected by the interaction between the two factors. Despite some small differences between species, results of this experiment suggest that microscopic stages of the native M. pyrifera and the invasive U. pinnatifida will respond similarly to OA and OW. The single effects of the local stressor, copper pollution, on the development of M. pyrifera and U. pinnatifida meiospore were examined. After settlement, meiospores of both kelps were exposed to five nominal copper treatments (control, 100, 200, 300 and 400 µg L-1 Cu) for 9 days. Analyses of total dissolved copper (CuT) concentrations in the blanks showed that nominal copper concentrations were reduced to 54, 91, 131 and 171 µg L-1 CuT (i.e., > 50% of the CuT was adsorbed onto the culture vessel walls). In the media with meiospores, the CuT also decreased: to 39, 86, 97 and 148 µg L-1 CuT in M. pyrifera, and to 39, 65, 97 and 146 µg L-1 CuT in U. pinnatifida (i.e., 6 – 15% of the dissolved copper was adsorbed by the cells). Meiospore germination decreased with increasing copper concentrations but gametogenesis was arrested under all copper treatments. The effective copper concentration causing 50% of arrested germination (Cu EC50) was higher for U. pinnatifida (231 µg L-1 CuT) than for M. pyrifera (157 µg L-1 CuT), suggesting ecological success for the invasive species in copper polluted environments; however, the subsequent inhibition of gametogenesis under all copper treatments indicated no difference in copper tolerance between both kelp early life stages. The reduction of CuT during the previous experiment occurred because copper might be adsorbed onto glass and/or plastic and this can be avoided using a proper trace metal clean procedure. Therefore, a review on the methodologies used in the literature on copper ecotoxicology of marine macro- and microalgae, specifically the use of trace metal clean procedures such as the labware used (glassware vs plasticware), methods of cleaning the labware (acid soaking and ultrapure water rinsing), stock solution preparation (copper source and acidification), and measurement and reporting of dissolved copper concentrations was performed. The main results of this review were that 50% of the articles did not specify the laboratory–ware, 25% used glassware and 25% plasticware; only ~30% of the studies specified cleaning protocols for labware to remove trace metal impurities; the copper form used to prepare the stock solutions was specified in ~80% of studies but acidification to stabilize the dissolved copper was performed in only ~20%; and the dissolved copper concentration was measured in only ~30% of studies. Based on these finding, a trace metal procedure was recommended for conducting copper ecotoxicological studies. A four-factor experiment was performed to investigate the interactive effects of OA, OW and copper pollution on the meiospore development of M. pyrifera and U. pinnatifida. Meiospores of both species were cultured under two seawater pH treatments (7.65 and 8.16), and two temperature treatments (12 and 16°C), and to the species-specific Cu-EC50 for 18 days. In both species, meiospore germination and germling growth rates significantly decreased in the copper treatment, irrespective of pH and temperature whereas gametophyte development for both species was inhibited by copper in all pH and temperature treatments. These results suggest that a local stressor (e.g., copper) is more important to the development of microscopic stages of M. pyrifera and U. pinnatifida than global climate change factors. In summary, results of this study indicate that meiospore development of M. pyrifera and U. pinnatifida will be able to tolerate future OA and OW. That tolerance might be related to: 1) macro- and microscopic stages of both kelps being able to use HCO3- and CO2 to support photosynthesis, therefore, the higher CO2(aq) availability due to OA (pH 7.20 to 7.65) will not affect their physiology; and 2) both M. pyrifera and U. pinnatifida have a wide temperature tolerance (4 to 30C°) which may allow them to perform well in a future warmer ocean (+ 4C°). In contrast, relatively high copper concentrations inhibited meiospore development of both kelp species. This finding indicates that local drivers (e.g., copper pollution) may be more important to physiological processes during meiospore development than global climate change factors. Furthermore, the responses of meiospores to the experimental abiotic factors (i.e., OA, OW and Cu) were similar between the study species, indicating that the invasive U. pinnatifida is unlikely to have an advantage over the native M. pyrifera in natural coastal environments.

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  • The use of combination tyrosine kinase inhibitors for the treatment of glioblastoma multiforme

    Nehoff, Hayley (2016)

    Doctoral thesis
    University of Otago

    Glioblastoma is the most common primary brain tumor which has a median survival of only 14.6 months. The central nervous system localization, heterogeneity of the cells and resistance to treatment constitute a significant challenge to establishing an efficient and durable therapy. Glioblastoma lesions contain a dense network of defective blood vessels which are permeable to high molecular weight constructs such as nanocarriers. Furthermore, glioblastoma lesions are known to depend upon several tyrosine kinases in order to facilitate their development, progression, invasion and treatment resistance. As a consequence, we assessed the cytotoxicity of multiple tyrosine kinase inhibitors (TKIs), singularly or in combination, against a panel of glioblastoma cell lines in vitro. The most promising combination of crizotinib, an inhibitor of Met and ROS1, and dasatinib, an inhibitor of SRC and focal adhesion kinase (FAK), were pursued as the lead compounds. In addition, these TKIs were encapsulated into polystyrene co-maleic acid micelles to improve their pharmacokinetic profiles in vivo by selective accumulation in tissues with fenestrated vasculature. The micelles were characterized based on their loading, charge, size, solubility and release rate. Both formulations were assessed for their ability to alter protein expression profiles, induce cell death and reduce proliferation. The ability of the treatments to prevent migration, invasion and angiogenesis in a panel of glioblastoma cell lines was also assessed. The micelles had favorable physicochemical characteristics, with a size sufficient to promote a prolonged plasma half-life, a near neutral charge to prevent opsonization and a steady release rate. The expression and phosphorylation of the target kinases Met, ROS1, SRC, and FAK were consistently reduced by the combination treatment. The combination treatment also reduced the expression of EGFR despite neither TKI targeting this receptor. The inhibition of these targets and subsequent suppression of downstream AKT activity induced apoptotic cell death in glioblastoma cells. The cell death following removal of the drug after a 72 h treatment period, defined as washout, was assessed to determine the ability of the cells to escape from treatment-induced cell death. Following washout, the apoptosis was maintained for 72 h following the removal of the drugs in the free but not the micellar formulations. The induction of cell death correlated with the induction of polyploidy in the free but not micellar formulations. This polyploidy was not causative of cell death but was associated with genetic instability. Both free and micellar formulations showed effective prevention of invasion, migration and angiogenesis in vitro. This study demonstrated the efficacy of the combination of crizotinib and dasatinib in a panel of glioblastoma cell lines. This combination strongly induced apoptotic cell death. Furthermore, the combination also effectively combated several treatment resistance pathways such as invasion and vascular mimicry, potentially augmenting the efficacy of the current therapies. The micellar formulations show comparable efficacy to the free formulations but also provide the potential for the improvement of in vivo pharmacokinetic parameters. In conclusion, the combination of crizotinib and dasatinib shows significant promise in vitro and warrants further investigation in vivo for the treatment of glioblastoma.

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  • Digital service problems: Prevention and user persistence in solving them

    Nili, Alireza (2016)

    Doctoral thesis
    Victoria University of Wellington

    The service sector is an important and consistently growing sector of the world economy. It is estimated that the sector will make up two thirds of the total world Gross Domestic Product (GDP). Information Technology (IT) has been an important contributor to the fast and high grow of the sector by increasingly digitising the production, delivery and use of services. IT has enabled multiple parties, including user support service staff, employees (internal IT users) and customers (external IT users) of an organisation, to engage in the production, delivery and use of digital services. Consequently, both users and user support service staff of the organisations have an increased responsibility to both prevent IT problems from occurring, and solve them when they do occur. Problems with ITs can occur at different stages of a digital service value chain (i.e. sequential steps/stages required to produce and deliver a digital service), and may lead to a service failure in the user’s mind. Examples include problems with a self-check-out machine at a library, problems with an online registration system that occurs for university students, or a website that does not include an online payment functionality a user expects. Numerous studies in both Information Systems (IS) and service literature have focused on the role of the service staff in both preventing and solving digital service failures, but few have considered the user’s role in these. This thesis includes four original articles. The first article emphasises that prevention from digital service failures must be considered before establishing effective approaches to solving the problems. The article presents a typology of technologies and technological approaches that customers and businesses can use to support prevention from these failures. The rest of the articles consider situations where an IT-related service problem has occurred, and address the user’s behaviour of persistence in solving their own IT problem. From the user’s perspective, their persistence in solving the problem contributes to achieving a satisfactory outcome, and from the organisational perspective, such an outcome is important for maintaining their user satisfaction. User persistence is important both when trying to solve an IT problem alone, and when using support services. Studying user persistence can help organisations to design their user support services in a way that encourages user persistence, resolves the problems more efficiently and cheaply; and maintains their user satisfaction. The study of user persistence included the use of focus groups for data collection purposes. Surprisingly, qualitative methodology literature has little to say on analytical approaches to focus group data – particularly interactive participant data. Therefore, a focus group analysis framework was designed (presented in the second article) and was used in the analysis phase of the user persistence study. The third article uses the framework in its analysis phase, and (a) presents a conceptual clarification of user persistence in IT problem solving, (b) identifies the factors that contribute to user persistence, (c) develops a theory to explain that why a user decides to persist with a method of solving IT problems, and (d) develops a theory to explain that why the user decides to persist with the overall process (collective methods) of solving the problem. The fourth article presents the results of evaluating the robustness of the two theories and shows that the two theories are confirmed. The thesis concludes with the ‘contributions and conclusion’ chapter where it presents a summary of the contributions of the four articles to IS theory, methodology and practice.

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  • Language learner cognition: Exploring adult migrants’ L2 activity beyond the classroom

    Navarro, Diego (2016)

    Doctoral thesis
    Victoria University of Wellington

    For years, understanding the relationship between behaviour and cognition has been a central concern of research conducted in the social sciences. In fields as diverse as anthropology, business, medicine, and education it is widely accepted that the development of practice (as a type of behaviour), depends on a precise understanding of how thought gets carried into action. However, studies investigating the complex interplay between a learner’s cognition (i.e. thoughts, knowledge, beliefs, and feelings about L2 learning) and their behaviour (i.e. language-related activity) are only recently garnering attention. In addition, only few studies have looked at this dynamic process with adult participants beyond the language learning classroom. Framed within the context of naturalistic language learning, this investigation explores the social construction of adult (over 30 years of age) L2 learners’ cognition in an ESOL setting. Specifically it aimed to answer the following research questions: RQ 1. What are the prior language learning experiences of a group of adult migrant learners living in New Zealand? RQ 2. How have these prior language learning experiences influenced the construction and development of their beliefs, assumptions, knowledge (BAK) about language learning? RQ 3. What is their perceived need for English in their current socio-cultural context? RQ 4. How do adult migrant language learners engage in language related activities beyond the classroom? RQ 5. How can this language learning behaviour be reflected in a model of language learner cognition? The study combined a longitudinal, ethnographic approach, with elements of narrative and case study inquiry. Six ‘recently arrived’ (Dunstan, Roz, & Shorland, 2004a) Colombian migrants (five refugees; one immigrant) were asked to talk about and discuss both prior and current experiences learning and using an L2. Through these lengthy in-depth, conversation-like interviews conducted in Spanish (the participants’ L1), told over time, a nuanced picture of the participants’ L2-related cognition emerged. As a result, I was able to more clearly observe the dynamic process in which a language learner’s mental life both impacts and is impacted on by language-related activity throughout their day-to day interactions. The participants are seen engaging in the L2 across a range of settings including at home, the doctor’s office, supermarkets and work. Moreover, in their accounts of this engagement we see change and revision (i.e. development) in their thinking about L2 learning and themselves as language learners, as well as their feelings toward the L2, other L2s and L2 users. A single participant was selected as an exemplary case to examine in detail, and facilitate understanding of this development. A case study approach allowed for a more intricate exploration of how the interplay between thought, emotion, and context impacted on the learner’s approaches to language-related activities. Issues regarding readiness to interact in the L2, intelligibility, language variety, and aversion to the ‘sound of English’ were seen as playing significant roles in the learner’s language development. This analysis resulted in the construction of a framework depicting language learner cognition in action. In terms of implications, this research supports the case for more qualitative research in SLA which centres learners’ perspectives of their L2 related experiences, particularly when so much of what seems to be affecting learning is the learners understanding of themselves and their actions. It also argues that studies in L2 cognition should focus their investigations on the developmental processes involved in the social construction of the mental factors which impact language learning and use. Finally, while belief studies in SLA are expanding the scope of their investigations – by looking to include more emotion and other affective factors, as well as by branching out into self-related constructs such as self-concept and self-efficacy in the foreign language domain – these studies remain limited in their almost microscopic view of learners’ mental lives. The picture of cognition I offer provides a more holistic understanding of this phenomenon which helps account at a macro-level for L2 behaviour. The study also highlights the potential and power of data gathering methods which foreground the participants’ voices and ideas (i.e. in-depth, unstructured interviews told over time) – reminding us that it is important when looking for what drives language learning behaviour to consider what the learners feel and think.

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  • Accessibility and development in rural Sarawak. A case study of the Baleh river basin, Kapit District, Sarawak, Malaysia

    Abdullah, Regina Garai (2016)

    Doctoral thesis
    Victoria University of Wellington

    To what degree does accessibility to markets correlate with levels of development? This is an important question for those living in remote, underdeveloped parts of Southeast Asia during the final phases of de-agrarianisation. My study recounts the experience of rural-based Iban households living in the Baleh river basin of the Kapit District (population of 54,200) within a day or less travel by river to the small market town of Kapit (with a population of 18,000). With no connecting roads to the rest of Sarawak and reliant almost entirely on river transport, the local economy remains underdeveloped and is losing population. My field work among 20 villages in three accessibility zones of the Baleh river basin was undertaken over the three month period of May-July 2014. Structured interviews were conducted with 20 village headmen (tuai rumah), 82 heads of household, and 82 individuals within the households. Data was also systematically collected on 153 other individuals, including both residents and non-resident members of these bilik-families. My conceptual framework draws on von Thünen’s model of agricultural land use in order to generate expectations about the possible effects of market accessibility. While the sale of vegetables and other commodities accords with expected patterns, most rural households are in fact dependent on other, largely non-agricultural sources of income. As a result there has emerged a disjuncture between the nominal and actual residence as those working age family members with residential rights to the bilik undertake paid work well beyond the agricultural margin. Unable to achieve desired standards of living by accessing local markets and services in a division with no cities or roads, the working age members of the bilik sustain their families by dividing their residence between two or more locations in what I call multi-local living. The income of nominally rural households is being increasingly determined by the human capital that individuals now apply to non-agricultural labour markets. This, in turn, is leading to a widening distribution of levels of ‘development’, across individuals, their multi-generational families and their rural communities. Multi-local living is unsustainable beyond the transitional phase of de-agrarianisation and as labour shifts out of agriculture and people move to towns, connections with rural residence are likely to diminish, notwithstanding the cultural ties, and disputes over realising market values of largely untitled land will continue to complicate the transition.

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  • The geochemistry of antimony in hydrothermal solutions

    Olsen, Nellie J. (2016)

    Doctoral thesis
    Victoria University of Wellington

    In this thesis, 30°C stibnite solubility experiments, ambient temperature X-ray absorption spectroscopic measurements of antimony in solution, and high temperature (70 to 400°C) stibnite solubility experiments were carried out in order to determine the aqueous antimony species present in equilibrium with stibnite in hydrosulfide solutions from pH = 3.5 to 12 and reduced sulfur concentrations from 0.001 to 0.1 mol kg⁻¹. Both ambient and elevated temperature solubility studies were conducted using a flow-through apparatus containing a column of stibnite grains though which solutions were pumped. Above 100°C, solubility experiments were conducted at slightly above saturated water vapour pressure to pressures of 300 bar. At 30°C, the stibnite solubility curve was best reproduced by a scheme of five species: Sb₂S₄²⁻, HSb₂S₄⁻, H₂Sb₂S₅²⁻, H₃SbS₂O, and Sb(OH)₃. At higher temperatures (≥ 70 °C), stibnite solubility at the conditions of the experiments was due to the following four species: Sb₂S₄²⁻, HSb₂S₄⁻, H₃SbS₂O, and Sb(OH)₃. Equilibrium constants were determined for the following five heterogeneous solubility reactions for the temperature ranges listed: [Please consult the thesis for details.] Stibnite solubility was independent of pressure at ≤ 350°C. At ~ 400°C, the solubility of stibnite was strongly dependent on pressure and decreased from Sbtotal = 0.015 to 0.0003 mol kg⁻¹ (~2000 to 40 ppm) with a pressure decrease from 300 to 160 bars. The Sb K-edge X-ray absorption spectroscopic (XAS) measurements of antimony in alkaline (pH = 10. 9 to 12) hydrosulfide solutions gave average first shell coordination environments that were consistent with the speciation model derived from solubility experiments for strongly alkaline solutions (i.e., Sb₂S₄²⁻ and Sb(OH)₃). XAS data enable the elimination of a speciation model involving only monomeric antimony complexes at strongly alkaline pH. Antimony speciation in near neutral to strongly alkaline pH’s is dominated by dimeric antimony-sulfide complexes at 30°C and sulfide concentrations > 0.001 mol kg⁻¹. With increasing temperature, antimony speciation becomes increasingly dominated by Sb(OH)₃. For hydrothermal solutions with sulfide concentrations between 0.0001 and 0.01 mol kg⁻¹, antimony-sulfide complexes are predominant at < 100°C, whereas antimonous acid, Sb(OH)₃, is the main aqueous species at contributing to stibnite solubility at > 200°C with the speciation in the intervening temperature range being dependent on the pH and sulfide concentration of the solution. For higher sulfide concentrations (i.e., ~ 0.1 mol kg⁻¹), HSb₂S₄⁻ and Sb₂S₄²⁻ control stibnite solubility to higher temperatures.

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