942 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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  • Part of the problem and part of the solution? Non-state armed groups and humanitarian norms in Burma/Myanmar

    Jagger, Stanley Jeremy (2016)

    Doctoral thesis
    University of Waikato

    Civil wars involving non-state armed groups in Burma have been driven by a complex mix of historical socio-political grievances and economic factors. The central government and its armed forces have conducted counterinsurgency campaigns against myriad rebel groups in ethnic areas virtually since independence in 1948. Civilian populations caught in these conflicts have suffered immensely as a consequence. The government and army have never completely controlled all the territory and people of the internationally recognised state as it exists on the map. Instead, in some areas it has been armed groups and welfare actors associated with them that have been responsible for limited administration and service provision to conflict-affected populations. Despite tolerance or support for this non-state governance in some areas, armed groups still present threats to the security of the constituencies they also claim to represent. This thesis assesses the factors that have facilitated or obstructed armed groups’ actions and the extent of their compliance (or not) in response to the norms against landmine use and the recruitment of children. While studies in other regions on armed groups and humanitarian norms have tended to consider policies of violence deliberately directed against civilians, the present study considers these less deliberate threats that armed groups in Burma present to the security of their own constituencies. It explores a set of theoretical propositions drawn from literature that has addressed armed groups from the perspectives of humanitarian engagement, sociology and political economy analysis of armed conflict. These contrasting approaches offer a more inclusive framework for analysis, considering the social, economic and coercive military and political structures influencing armed groups, affected populations and humanitarian actors engaging with them in relation to these issues. This thesis contends that perceived legitimacy and the role of armed group associated welfare and civil society actors have been significant influences on attempts to ameliorate the impact of these issues. The perspectives and influences of legitimacy diverge, however, between international support for the prohibition of landmine use and underage recruitment, and local perceptions, from armed group constituencies and the government, of the groups as credible armed actors. Localised economic agendas combined with geographical dispersion and weak organisational cohesion have also been factors leading to less compliance with these protection norms. The findings indicate that there is also considerable divergence in the extent of compliance between the two norms. Whereas landmine use remains perceived as militarily necessary to most armed groups in Burma and related to their maintenance of local legitimacy, children involved with armed groups are seen as less vital militarily, and external engagement with armed groups to address this issue has met with more acceptance over time. In the light of bilateral ceasefires and ongoing negotiations since 2012, the willingness and capacity of the armed groups and their welfare wings to address these concerns for conflict-affected populations will be important for their future support and for lasting political settlements.

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  • Carbon dioxide and methane emissions from the Te Arawa lakes of Rotorua, New Zealand

    Santoso, Arianto Budi (2016)

    Doctoral thesis
    University of Waikato

    One of the biggest issues confronting humankind today is global warming due to the rapidly increasing greenhouse gas (GHG) emissions, namely CO₂, CH₄ and N₂O. The Intergovernmental Panel for Climate Change (IPCC) has prepared an emission reduction strategy. So far, inland waters, including lakes and reservoirs, have not been included in the global carbon cycle. However, the contribution of inland waters to global CO₂ and CH₄ emissions has been identified to be important. Inland waters are also known to be a major sink for GHG emissions by attenuating carbon that would otherwise be transported from the terrestrial landscape to the ocean. Lakes are also very sensitive to climate change as well as to human impacts generally, and these effects will need to be considered in understanding the future role of lakes in the global carbon cycle. This study aimed to improve understanding of CO₂ and CH₄ emissions from lakes, and to quantify these emissions under changing climate and nutrient loading regimes in a regionally discrete group of lakes of volcanic origin in North Island of New Zealand. It included a comprehensive field study of one lake, application of process-based numerical modelling to the lake, and collation and critical analysis of existing datasets for the group of lakes. The primary study site was Okaro, a monomictic eutrophic lake where a major restoration program has been in place for more than one decade. The study also extended to 10 other lakes in order to give insights into effects of different nutrient and mixing regimes on carbon sources and sinks Based on observations over a one-period (September 2013 – October 2014), Lake Okaro accumulated CO₂ and CH₄ in the hypolimnion during summer stratification. These gases were entrained into surface waters as lake started to turnover just prior to complete mixing in winter. As recorded in many other eutrophic lakes, the net CO₂ flux was mostly from the atmosphere to the lake. However, CO₂, together with CH₄, escaped from the lake as a pulsed emission in winter. Using a simple annual mass balance model it was calculated that, ~31% of CH₄ sourced from the sediment escaped to the atmosphere through diffusive flux. The remainder was likely to be oxidized in the water column. The model also showed that on an annual basis the net CO₂ emission is out of the lake. These findings suggest that eutrophic lakes may actually be net emitters of greenhouse gases and that pulsed emissions may be an important contributor to the direction of the flux. This study did not account for CH₄ ebullition, however, and therefore the magnitude of GHG emissions from this lake is likely to be lower than predicted. The effects on CO₂ and CH₄ emissions from Lake Okaro of a warming climate and changes in nutrient loads was simulated using a coupled hydrodynamic-ecological model (GLM-AED2). Future possible changes were simulated by altering model forcing data, increasing air temperature by 2.5 °C. Internal and external nutrient (nitrogen and phosphorus) loads were also either halved or increased by one half. Model simulations showed that annual CO₂ uptake by the lake was enhanced under a warmer climate, but emissions of CH₄ increased during lake overturn as a result of greater diffusive fluxes. Total GHG emissions, as CO₂ equivalent (kg CO₂-eq m⁻² y⁻¹), from the lake were predicted with model simulations to increase by 27% under a warming climate, relative to present conditions. This increase would be reduced to 19% if nutrient loading was halved. A first-order diagenesis model was used to estimate the carbon deposition in the 11 Te Arawa lakes. The most productive lakes, using chlorophyll a as a proxy, had higher rates of carbon deposition in the bottom sediments than the less productive lakes. However, burial efficiency (buried carbon: deposited carbon) was lower in productive lakes meaning that most of the deposited carbon in these lakes is remineralized back into the water column. This remineralization process can be associated with CO₂ and CH₄ emissions from the lake. The results of this study highlight that eutrophic lakes may contribute emit higher levels of GHGs to the atmosphere than has previously been estimated, primarily as a result of pulsed emissions associated with the onset of seasonal mixing, at least in monomictic lakes. Eutrophication and climate warming are likely to enhance GHG emissions from lakes. The findings from this study have important implications for global GHG fluxes and indicate that fluxes into or from lakes need to be included in inventories. Reducing nutrient loads to lakes could offset some of the predicted increases in emissions of GHGs that are likely to occur with climate warming.

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  • Temporal variability in the water quality of a deep temperate oligotrophic lake

    Kpodonu, Alfred Theodore Nutefe Kwasi (2016)

    Doctoral thesis
    University of Waikato

    Lakes change over time in response to climate and catchment disturbance, even in the absence of anthropogenic stressors. This temporal change may impact the setting of reference conditions for lakes. Many sources of information including monitoring data, historical information, modelling and paleolimnology can be used to understand temporal dynamics of lakes. In this thesis, the contribution of catchment disturbance by volcanic eruptions, introduction and proliferation of invasive mammals, and climate variability, to temporal variability in lake reference conditions was studied in a deep lake (Lake Okataina) in the Central North Island in New Zealand that is close to reference state. The lake and its catchment have been subject to anthropogenic and natural biotic and abiotic disturbances during the last millennium. Polynesian settlements were thought to have been established in and around the lake catchment in the early 14th century following the Kaharoa eruption of AD 1314 ± 12. Mt Tarawera erupted 10 June 1886 and damaged large tracts of vegetation in the Okataina catchment. Following European settlements around the catchment in the early 20th century, mammals which were hitherto not present, were liberated into the forest and rainbow trout (Oncorhynchus mykiss) were released into the lake. Large populations of the dama wallaby (Macropus eugenii), wild boar (Sus scrofa), red deer (Cervus elaphus) and the Australian brushtail possum (Trichosurus vulpecula) exist in the catchment. These mammals have become the “new normal” in many New Zealand catchments. To understand the role of volcanic eruptions and invasive mammals in shifting baseline conditions of lakes, two 49 cm cores were retrieved from a central deep location at Lake Okataina. The core was sliced at 1 cm intervals and slices dated using 210Pb, with the tephra from the Kaharoa and Tarawera eruptions used to validate the dates and benchmark events. Dating indicated the length of the core encompassed the period between the Kaharoa eruption of AD 1314 ± 12 and 2009. Various inorganic and organic geochemical proxies in the sediment core slices were analysed to determine: changes in catchment erosion, phosphorus speciation, phytoplankton community assemblage, primary productivity, sources of organic matter loading, redox potential, and internal phosphorus loading to the lake. A suite of statistical techniques, including structural equation modelling (SEM), general linear modelling (GLM), nonmetric multidimensional scaling (NMDS) and correlation analysis was used to interpret vertical changes in the composition of the core slices and relationships amongst analytes. SEM was used to compare the relative importance of climate and catchment disturbance in changing the primary productivity of Lake Okataina after the Tarawera eruption (1886) and European settlement (1900). Changes in historical primary productivity inferred from total organic carbon in sediment core slices were modelled as a function of geochemical proxies for erosion (Al and Ti) and records of climate variability (Southern Oscillation Index and Temperature Anomaly). The results of this study showed that erosion is the main driver of changes in primary productivity although climate contributes substantially to the variations, and also contributes to changes in erosion itself. The relationship between phosphorus speciation and algal community dynamics in the lake over the past ~ 700 years was established by applying NMDS and GLM to sequentially extracted phosphorus species and algal pigments from the sediment core. Pigments representing diatoms, cyanobacteria, chlorophytes and chryptophytes were measured vertically through the core at 1 cm intervals, as well as phosphorus associated with apatite and CaCO₃, Fe and Mn (oxy) hydroxides, Al (oxy) hydroxides and labile phosphorus. Highly significant correlations were established amongst the algal groups and the phosphorus fractions. The NMDS showed diatoms were strongly correlated with phosphorus fractions associated with permanent burial (apatite and CaCO3 and Al (oxy) hydroxides), while cyanobacteria and chlorophytes were correlated with potentially bioavailable phosphorus (Fe and Mn (oxy) hydroxides and labile phosphorus). Chlorophytes, cyanobacteria and chryptophytes co-dominated when diatom populations were reduced, and vice versa. Using GLM, phosphorus fractions could be used to hindcast historical variations in the composition of algal communities (as inferred from pigments), with the exception of alloxanthin (representative of chryptophytes). Long-term changes in the water quality of Lake Okataina were inferred from sediments deposited from 1836 to 2009, during which time the forested catchment was disturbed by both a pyroclastic volcanic eruption (Tarawera 1886) and invasive mammals (commencing c. 1900). Multiple sediment geochemical proxies were analysed stratigraphically to ascertain trends in organic matter loading (TOC, TN, δ ¹³C and δ ¹⁵N and TOC/TN ratio), primary productivity (Ni, Cu), redox potential (U, V and Mo) and phosphorus retention capacity (Al/Fe and Al/P ratios) of the lake. The chronosequence of the proxies showed that the main source of organic matter loading to the lake is algae although terrestrial loading was increased immediately after the eruption of 1886. Erosion of inorganic materials was relatively high after the eruption but decreased after about twenty years, possibly linked to vegetation regrowth. After 1920 there was a sustained increase in the terrestrial flux of inorganic material. The redox potential of the lake also changed substantially from about 1930, suggesting a reduced degree of bottom water oxygenation. Primary productivity increased considerably after about 1960, while the phosphorus retention capacity of the lake has substantially decreased over the last 50 years. Using eleven years (2003 to 2013) of contemporary monthly monitoring data, I tested for patterns of temporal coherence in three deep oligotrophic lakes of the Rotorua region, which have similar catchment geology, trophic state and morphometry. Variables measured in the upper 1 m and bottom 2 m of the lakes, or variables calculated from depth profiles, as well as water level, were included in the coherence analysis. The directly measured variables included temperature, dissolved oxygen, nutrients and chlorophyll a, and the calculated variables were depths of the thermocline, deep chlorophyll maximum and euphotic zone, as well as Schmidt stability. Temporal coherence was calculated for each of variable using Pearson correlation coefficient values after LOESS decomposition. The average temporal coherence for the lake pairs was high (r=0.65) indicating that the variability in most lake water quality properties is not lake-specific, but instead responds strongly to regional climate. Surface variables were more coherent than those at depth. Physical variables were more coherent than chemical variables, and the variables derived from the depth profiles were less coherent than directly measured variables. Our results indicate the strong influence of regional climate on physical variables in particular, which propagates into progressively reducing influence on chemical and biological variables. The effects of climate are progressively filtered from physical to chemical and biological variables. Coherence analysis is a useful tool to tease apart the relative influence of climate change on these variables and provides a contemporary context for lake behaviour in response to climate forcing, rather than using specific lakes which are benchmarked to a pre-anthropogenic era. The results of this thesis show that while the effect of eruptions is catastrophic, it is also relatively transient compared with the recent impacts of invasive mammals and climate warming, which are more continuous perturbations to the lake and landscape dynamics. Climate variability and invasive mammals tended to act synergistically to increase catchment loads of sediment and nutrients to the lake, effectively creating a shifting reference condition for a lake that would otherwise be considered relatively stable. With current climate change scenarios for New Zealand showing increasing temperatures, and without significant control of exotic mammals, recent trends in phytoplankton assemblages observed in this study, towards domination by cyanobacteria and chlorophytes, may be expected to be reinforced, and bottom-water oxygen levels may decline further. In setting targets for lake restoration goals, management of populations of invasive mammals should be included where there are substantial areas of native forest, because of the potential for these species to reduce vegetative cover, increase loads of sediment and nutrients to lakes, and negatively impact water quality.

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  • The control of wind and waves on sediment transport asymmetry and the long-term morphological development of estuaries

    Hunt, Stephen (2016)

    Doctoral thesis
    University of Waikato

    Most theories on the equilibrium shape of estuarine basins highlight the dominance of tidal asymmetry in controlling the hydrodynamic and morphodynamic feedbacks that ultimately lead to a stable morphological state. This thesis uses field measurements, numerical modelling and sediment deposition records to investigate how waves interact with tidal processes and how these interactions influence sediment transport and the non-linear feedbacks between hydrodynamics and estuarine basin morphology. Numerical modelling experiments were conducted over a series of idealised estuaries representing different stages of infilling, which show that wind and waves are far more efficient than tides at shaping intertidal areas, with the effect being subtly dependent on the depth distribution in the intertidal. Moreover, the wind and wave climate can substantially alter the hydrodynamic regime over the entire estuary and in intertidal areas can exert a much greater control on asymmetry than tidal currents alone, which dominate in the deeper channels. Under the effect of tides alone, currents over intertidal flats are to found to remain flood-dominant as the estuary infills, thus promoting continued accretion until tidal currents become too weak to entrain sediment. Therefore, estuaries with only tidal currents are likely to evolve into in-filled areas of salt-marsh or mangrove with drainage channels, whereas fetch-aligned estuaries (in which wind-waves are common) have a greater probability of attaining deeper hydrodynamically-maintained stable intertidal areas. Although waves have little direct influence on hydrodynamics within the subtidal channel, the tidal asymmetry is controlled by the height and volume of the intertidal areas and therefore is indirectly influenced by wave activity. The higher-energy, infrequent storm-wave events can considerably modify estuarine morphology over short timescales whereas lower-energy but perpetual effects like the tides operate continuously and so the relative contribution of such events in shaping the long-term morphological evolution can be considered on a range of timescales. Within this thesis a combination of hydrodynamic measurements, sediment deposition records and numerical modelling are used to determine the conditions under which observed waves are morphologically significant. Morphological significance is defined as when waves influence tidal and suspended sediment flux asymmetry and subsequently infilling over geomorphological timescales. By comparing a fetch-aligned and a non fetch-aligned mesotidal basin, it is shown that for a sufficiently large fetch, even small and frequently occurring wind events are able to create waves that are morphologically significant. Conversely, in basins with a reduced fetch, wave events are less frequent and therefore of far less morphological significance. The role of tidal range in controlling sediment transport is investigated through consideration of its influence on bed shear stress, τmax. The decrease in bed shear stress associated with greater water depths is compared to increases owing to the larger fetch that accompanies the increased tidal range and the generally stronger currents associated with larger tidal range. Here, it is shown that during neap tides the reduction in water depths around high water and tidal currents are not offset by the reduction in fetch. Thus, it is shown that the basin-averaged τmax is similar during both spring and neap tides in addition to the shorter duration of slack water during neap tides. Consequently, as τmax is lower in the subtidal channel during neaps, the sediment gradient (and hence sediment transport potential) between tidal flats and channels is greater. Thus it is concluded that sediment deposition potential may actually be increased during a neap tide. This result is in sharp contrast to previous observations from microtidal wave-dominated environments, in which differences between spring and neap result in increased erosion during spring tides. Overall, this thesis shows that short period locally generated waves can be considered a morphologically significant hydrodynamic process within estuaries. With increased fetch, waves become more morphologically significant relative to tides as even low, frequent wind speeds are able to generate waves that are capable of controlling patterns of sediment transport.

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  • Exploring teacher transition in New Zealand primary schools: The impact of changing class levels on teacher professional learning

    Carlyon, Tracey (2016)

    Doctoral thesis
    University of Waikato

    This thesis provides an in-depth understanding of teacher transition and the impact of this on teacher professional learning. The focus is on the transition that occurs when a teacher changes from teaching in one class level to another in New Zealand primary schools. Of particular interest is learning more about how teachers’ perceptions of transition are developed, the outcomes that are generated for them and other stakeholders, how teachers negotiate transition, and the role of school leadership in teacher transition. This research uses case study methodology, and although it is primarily qualitative in nature, a mixed methods approach was applied to gather both qualitative and quantitative data. Data were collected from 536 teachers via an online survey and from four teachers by means of a semi-structured interview. By converging and comparing broad numeric trends that emerged from the quantitative data with the detail from the qualitative data, I was able to gain a more in-depth understanding of teacher transition and the impact of this on teacher professional learning. Findings from this study suggest that there are significant benefits for teachers and other stakeholders when teachers transition. These highlight that transition has a very significant impact on teacher learning, and stimulates the interplay between a teacher’s professional learning and professional identity which can result in changes in practice and pedagogy. The influence from these changes is shown to strengthen a teacher’s professional identity, bring about more effective teaching and extended professionality. Those theories which suggest that teacher development occurs in sequential stages and that all teachers progress through these stages in a linear fashion as they become more experienced, are challenged, and the suggestion that teachers require opportunities, such as transition at different times during their careers for professional development and learning, is supported. There are four major implications for teacher education that have emerged from the findings of this study. First, they suggest that cognisance be taken of the opportunity that transition provides for teacher learning and that transition is conceptualised as a form of professional learning and development. Secondly, they indicate that when tensions are acknowledged and clearly understood, teachers are better placed to see transition as a positive opportunity for professional learning and development. The third set of implications concern teachers being given sufficient opportunities to prepare, both mentally and physically, for transition. Finally, the study shows that the success of teacher transition is fundamentally dependent on the action of school leadership to ensure that school cultures and systems are conducive for teachers to change class levels successfully. The new information from this study gives support to initial teacher educators, student teachers, teachers, school leaders, schools, Boards of Trustees and policy makers to ensure all teachers can successfully transition. In an effort to build knowledge about teacher transition, this study advocates that all teachers are given the chance to take full advantage of the unique opportunity for rich professional learning and development that transition between class levels offers.

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  • Pululima Faifai Pea: Establishment of Sāmoan Immersion ECE Education Centres & Bilingual Units in Primary and Intermediate Schools

    Vaitimu Tuāfuti, Patisepa (2016)

    Doctoral thesis
    University of Waikato

    Sāmoan Immersion Preschools (Ā’oga ‘Amata) and Bilingual Education units covering from year one to year eight of school have become well established in some areas in the Auckland region since the 1980s, due to the commitment, support and contributions of parents, the Sāmoan community, church leaders, families and some schools. Given that parents, families and communities appeared to have played such a seminal role in their establishment, this research was set out to investigate Sāmoan parents’ lived experiences in relation to the establishment of ā’oga ‘amata and Sāmoan bilingual education units. Fa’afaletui phenomenology, a term I developed in the process of conducting the research, was employed as a culturally appropriate coupling methodology. Phenomenology is about lived experiences and fa’afaletui is a process and procedure of revealing participants’ lived experiences. Insights into parents’ lived experiences were obtained by using various methods namely: questionnaire, focus group discussions, individual interviews, couple interviews and testimonies. The lived experiences were collated from the recounts of past events. The recounts were analysed for themes, which arose from the comments and interpretations of the past events, and the expressions of emotions attached to the events. Observations and analyses of past events highlight many challenges that the participants experienced. Challenges ranged from financial difficulties and lack of resources, to lack of understanding about bilingual/immersion education. What the results make clear is the resilience of the participants in defending what they believe is right as far as fa’asāmoa is concerned, and the powerful role of emotions in personal and educational lives. Resilience and emotions are coefficients in the results and they have theoretical importance in understanding the research findings.  

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  • The Ethics of Reading: Levinas and Gadamer on encountering the other in literature

    Dougan, Melanie Jane (2016)

    Doctoral thesis
    University of Waikato

    This dissertation explores the question ‘can we encounter the Other through the mediation of literature?’ The question reflects an increasing interest in ethics by literary theorists and particularly in the application of Emmanuel Levinas’s work to the field of literary studies. I identify a major concern with this trend that has been largely overlooked: Levinas states that the Other cannot be encountered through the mediation of literature. With questions of justice towards texts and the necessity to respect alterity at the forefront, I argue that Levinas’s concerns cannot be overlooked. To explore a possible solution to the problem I first consider Levinas’s concerns with literature and argue that his adamant stance on the Other and literature stems not so much from the arguments he puts forward but a human conviction that the ethical is limited to the immediate face-to-face encounter. I suggest that this desire which cannot be fully accounted for by his philosophical account finds its origin in the Holocaust but, more than this, can be seen as the ethical saying interrupting and disturbing his writing. The answer to the question of the thesis hinges on the interpretation of both who the Other is and what exactly the encounter with the Other means for Levinas. Unlike most literary theorists, I do not look for ways in which Levinas’s ethical work is portrayed in literary texts; I am interested in the text as Other and the reader’s responsibility towards it rather than situations or characters that fit the face-to-face model. I draw upon Hans-Georg Gadamer’s hermeneutics to both consider the relation one has with regard to a text and to clarify who exactly the Other might be. I conclude by trying to rehabilitate the idea of author but couch this in Gadamerian terms, it is the world view or horizon of the text that we encounter as other and I name this ‘author’. My consideration of Gadamer confirms that we feel that we encounter alterity in literature and he suggests a way to say something about this that does not annihilate otherness. I then return to the problem of literature for Levinas and find that I can answer the question of the thesis affirmatively, with some qualification. I argue that the Levinasian encounter is best understood by analogy to the Kantian sublime. We cannot encounter the Other at all except through experiences that signify or remind us of this primordial encounter. Lived encounters with the other are structurally similar to and signify the encounter with the Other which in turn gives the everyday encounters their meaning. I combine this interpretation with Jean Baudrillard’s argument regarding representation in photography which posits a view of a productive presentation of the fiction of reality rather than a hollow representation of an absent reality. With a positive answer to the question of the thesis in hand, I read Edgar Allan Poe’s short story, ‘The Purloined Letter’ to explore the implications of my research in a concrete example.

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  • Harakeke fibre as reinforcement in epoxy matrix composites and its hybridisation with hemp fibre

    Le, Tan Minh (2016)

    Doctoral thesis
    University of Waikato

    Over the last few decades, due to increasing global awareness of environmental issues, there has been great interest and motivation in research to develop natural fibre composites to replace glass fibre composites in certain applications. Harakeke fibre known as New Zealand flax or Phormium tenax used to be an important export material in New Zealand in the early twentieth century, but its production reduced due to the availability of synthetic fibres midcentury and competition from other natural fibres such as sisal and flax. Now, harakeke plants are planted mainly for landscaping with some fibre extracted from harakeke leaves used for craft goods and traditional products of Maori people who were the earliest settlers in New Zealand. Only two family workshops in the country are currently extracting harakeke fibre for this purpose. The aim of this thesis was to assess if harakeke fibre has potential for reinforcement in polymer composites and to assess the hybridisation of harakeke/hemp hybrid composites. Both short and long fibres were used as reinforcement, while a low viscosity epoxy resin was used as the matrix. Short fibres were alkali treated before being used to reinforce epoxy, while long fibres were used as supplied. Short and long fibres were aligned using dynamic sheet forming and manual carding, respectively. Composites were produced using hand lay-up and compression moulding. The physical and mechanical properties of fibres and composites were tested following ASTM and ISO standards. The surfaces of fibres and fracture surfaces of composites were assessed microscopically using optical microscopes and scanning electron microscope (SEM). Short harakeke and hemp fibres were alkali treated at elevated temperatures in a fibre pulping digester with a solution of 2wt% NaOH or 5wt% NaOH/2wt% Na2SO3. Single fibre tensile testing was carried out on untreated and treated fibres. It was found that harakeke fibre treated with NaOH and hemp fibre treated with NaOH/Na2SO3 retained their tensile strength and Young’s modulus compared to the untreated, while harakeke fibre treated with NaOH/Na2SO3 was degraded. Fibre surfaces and fibre separation were evaluated revealing that fibres treated with NaOH/Na2SO3 had better separation and rougher surfaces compared to those treated with NaOH. Densities of harakeke and hemp were found to increase after alkali treatment. Fibre lumens were found to make up significant volume of fibres with 41% of single fibre volume and 21% of fibre bundle volume for harakeke fibre and 18% and 11% for hemp fibre, respectively. Lumens were found to be a major factor contributing to porosity of long aligned harakeke composites. Mechanical properties including tensile, flexural and fracture toughness of composites containing aligned short 2%NaOH treated harakeke fibre with different fibre contents were evaluated and compared with randomly oriented harakeke/epoxy composites. It was found that all properties increased with fibre content. Tensile strength and Young’s modulus of the aligned short fibre composites at the optimum fibre content of 46wt% were 136 MPa and 10.5 GPa, respectively. These values are higher than any reported in the literature to date for natural fibre composites excluding those where hand-layup or a continuous fibre form has been produced and furthermore, these values overlap with those achieved using these procedures. Mechanical properties of aligned long harakeke composites were also evaluated. The tensile strength and Young’s modulus were comparable to those for sisal and hemp composites in the literature and their specific values were comparable to those for glass fibre composites. Impact strength and fracture toughness of harakeke fibre composites that have not been seen previously in the literature were found to be 132 KJ/m2 and 7.69 MPa.m-1/2, respectively, at a fibre content of 63wt% for aligned long harakeke/epoxy composites. These values are higher than any reported in the literature to date for natural fibre polymer composites. A Rule of Mixtures based model was developed for predicting aligned long harakeke fibre composite strength with the assumption that composites fail when fibres with the lowest failure strains failed and considering the effect of porosity. It was found that porosity affected tensile strength as well as Young’s modulus of the composites. Aligned long or short harakeke/hemp hybrid biocomposites were prepared with different fibre lay-up and weight ratios between harakeke and hemp and their mechanical properties were assessed. While tensile properties, impact strength and fracture toughness (KIC) of the harakeke/hemp hybrid biocomposites were found to be independent on fibre lay-up, flexural properties were found to be dependent as would be expected due to the influence of second moment of area. The fibre failure strain based hybrid effect (FS hybrid effect) defined as the enhancement of low elongation fibre due to presence of high elongation fibre in composite and the Rule of Mixtures based hybrid effect (ROM hybrid effect) termed as the deviation of a certain property from the Rule of Mixtures were assessed for harakeke/hemp hybrid biocomposites. While the FS hybrid effect was found not to be observed, ROM positive hybrid effects were found to be observed for fracture toughness of aligned short harakeke/hemp hybrid biocomposites with different fibre lay-ups and different relative fibre contents. ROM positive hybrid effects were also found to be observed for flexural modulus for comingled harakeke/hemp fibre composites at different relative fibre contents. Tensile properties and impact strength were found to obey the Rule of Mixtures.

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  • Developing groundwater and surface water interaction methods for complex hydrological systems

    Shokri, Ali (2016)

    Doctoral thesis
    University of Waikato

    Methods and models associated with the interaction of surface-subsurface water flow have been widely employed in many environmental studies over the last decade. However, in spite of considerable effort, understanding the impact of both artificial and natural aspects of the connection between surface water and groundwater systems still remains a challenge for groundwater and surface water models. In this doctoral study, two types of complex and integrated problems are identified as knowledge gaps in coupled surface and subsurface flow studies (i) interaction situations that arise from use of artificial drains in agricultural catchments, and (ii) complex flow situations that sometimes arise as a result of a combination of near surface aquifers which are both perched and leaky. The specific objectives of this research project were (1) to improve classical tile drain spacing design methods; and (2) via a case study, to assess the role of semi-impermeable layers influencing the interaction between surface water and a regional groundwater system. To meet the first objective the DrainFlow code is developed. DrainFlow is a new, fully distributed, physically based and integrated surface-subsurface flow code that is designed for water movement in tile/mole drains, open drains, and saturated/unsaturated zones. DrainFlow, applied to examples of drainage studies, is found to be quite flexible in terms of changing all or part of the model dimensions as required by problem complexity, scale, and data availability. This flexibility gives DrainFlow the capacity to be modified to meet the specific requirements of varying scale and boundary conditions as often encountered in drainage projects. In addition, the classical well-known Hooghoudt drain spacing equation is modified. It is shown via comparison with numerical models that the Hooghoudt equation can overestimate water table height and therefore yield drain spacings which may be too wide. The modified expression yields improved accuracy as measured against the numerical reference model. To meet the second objective, the effect of a thin semi-impermeable and fractured layer between two relatively permeable volcanic formations is investigated in an industrial catchment system at Kawerau, New Zealand. It is concluded that subtle near-surface geological features may have a critical role on controlling the volume and pattern of the flow exchange between the surface, subsurface flow and regional groundwater systems. This doctoral thesis overcomes some weaknesses of isolated surface and subsurface flow models and some constructive and practical approaches are developed to enhance the previous methods.

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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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  • Understanding the construction of belonging in a for-profit ECE centre: An ethnographic study

    Westerbeke, Lynley Ann (2016)

    Doctoral thesis
    University of Waikato

    Participation in high quality early childhood education [ECE] is recognised as having long ranging academic and social benefits for children, especially those from disadvantaged backgrounds (Mitchell, Wylie & Carr, 2008). In 2010 the ECE Participation Programme was successfully introduced to increase enrolment in ECE for targeted groups, such as Māori, Pasifika, and low income families. I argue that focusing on increased participation alone is limiting and participation requires being viewed alongside the notion of belonging. With the majority of children participating in for-profit ECE centres in Aotearoa New Zealand (Ministry of Education, 2015) I suggest that what children are participating in merits greater investigation. In this thesis belonging is positioned as not simply obtaining membership, but utilising Rogoff’s (2003) understanding of participation, it is viewed as something which is highly influential, where core values are transmitted and transformed. The research questions guiding this thesis are: 1. What affordances and challenges to belonging are identified by stakeholders participating in a privately owned, for-profit, ECE centre? 2. How is the ethical stewardship of Te Whāriki reflected in the leadership’s decision making? This thesis used a critical ethnographic methodology, and was conducted over a nine month period in a for-profit ECE centre, with the researcher in the role of participant observer. The centre is located in a lower socio-economic area of an inner city suburb and is accessed by families who at the time of the study had only 30% of its parents in paid employment. The majority of children identified as Māori and lived in close proximity to the centre, and all teachers at the centre identified as Pākehā. The stakeholders identified for this study were the children, their parents and the teachers. Three teachers participated in the study and four children were selected for case study, aged between two and four and a half years. Data was generated primarily through semi-structured interviews with the children, their parents and the teachers, and observation of the setting. The data was viewed utilising Rogoff’s (2003) three foci of analysis, with three contributing factors to belonging identified by participants; values, relationships and leadership. The thesis argues that belonging is complex and participation in for-profit ECE services is an ethical concern, not only for the children and their families but also for teachers. To make sense of the aligned yet often contradicting perspectives of the stakeholders I propose a belonging framework, conceptualised to bring understanding to the construction of belonging within the centre. It suggests that belonging to the centre can be viewed from three distinct viewpoints; it can be observed, lived, and framed. The study evidenced that the day-to-day lived experiences of the children are not fully known by parents and, while also lived, belonging is primarily observed for this cohort. Within the context of lived belonging the teachers’ and leadership’s philosophical and pedagogical approaches meet, and often collide. The child is placed at the heart of the framework where belonging is lived and it is here that meaning for this group is primarily created, and cultural values are transmitted and transformed. The third perspective is how belonging is framed, with the leaders’ operational decision making setting the parameters for the stakeholders’ participation. It is in this space that the actual values guiding the setting are revealed. My thesis aims to explain the impact on the stakeholders’ sense of belonging when a government funded centre is driven by agendas not fully aligned with the intentions of the democratic and bicultural curriculum, Te Whāriki. This study adds to the literature on for-profit ECE services, participation in ECE in Aotearoa New Zealand, and leadership in ECE.

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