569 results for Doctoral, 2008

  • Care ethics and brain injury

    Butler, Mary (2008)

    Doctoral thesis
    University of Otago

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

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  • Dissolved organic matter in New Zealand natural waters

    Gonsior, Michael (2008)

    Doctoral thesis
    University of Otago

    xi, 186 leaves :ill. (some col.), col. maps ; 30 cm. Includes bibliographical references. "1st of April 2008". University of Otago department: Chemistry.

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  • Transforming Folk: Innovation and Tradition in English Folk–Rock Music

    Burns, Robert G. H. (2008)

    Doctoral thesis
    University of Otago

    From a mixed methodology perspective that includes ethnology, musicology and cultural anthropology, I argue that, despite initial detachment from folk revivalism, English folk–rock has moved closer to aspects of tradition and historical status and has embraced a revivalist stance similar to that of the folk revivals that occurred earlier in the twentieth century. Whereas revivalism often rejects manifestations of mass culture and modernity, I also argue that the early combinations of folk music and rock music demonstrated that aspects of preservation and commercialisation have always co–existed within this hybrid musical style. English folk–rock, a former progressive rock music style, has emerged in the post–punk era as a world music style that appeals to a broad spectrum of music fans and this audience does not regard issues such as maintenance of authenticity and tradition as key factors in the preservation process. Rock music has remained a stimulus for further change in folk music and has enabled English folk–rock to become regarded as popular music by a new audience with diverse musical tastes. When folk music was adapted into rock settings, the result represented a particular identity for folk music at that time. In a similar way, as folk music continues to be amalgamated with rock and other popular music styles, or is performed in musical settings representing new cultures and ethnicities now present in the United Kingdom, it becomes updated and relevant to new audiences. From this perspective, I propose that growth in the popularity of British folk music since the early 1970s can be linked to its performance as English folk–rock, to its connections with culture and music industry marketing and promotion techniques, and to its inclusion as a 1990s festival component presented to audiences as part of what is promoted as world music. Popularity of folk music presented at world music festivals has stimulated significant growth in folk music audiences since the mid–1990s and consequently the UK is experiencing a new phase of revivalism – the third folk revival.

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  • Diffusive Gradients in Thin Films for Inorganic Arsenic Speciation and Electrothermal Atomic Absorption Spectrometry with a Coupled Microcolumn for Trace Metal Speciation

    Panther, Jared Graeme (2008)

    Doctoral thesis
    University of Canterbury Library

    This thesis is directed towards the development of the diffusive gradients in thin films (DGT) technique for the measurement of total dissolved As, and for As speciation measurements. In addition, a preliminary investigation of a novel laboratory-based method for measuring labile metal species was carried out; this method involved the coupling of a microcolumn of adsorbent with a standard electrothermal atomic absorption spectrometer. An iron-oxide adsorbent was utilized for As measurements by DGT. The diffusion coefficients of inorganic Asv and AsIII> were measured through the polyacrylamide diffusive gel using both a diffusion cell and DGT devices. A variety of factors that may affect the measurement of total As by DGT were investigated. These factors, which included pH, anions, cations, fulvic acid, FeIII-fulvic acid complexes, and colloidal Fe, may affect the adsorption of the As species to the iron-oxide, or may affect the diffusion coefficients of the individual As species. The DGT method was further developed to selectively accumulate the AsIII species in the presence of Asv. This was achieved by the placement of a negatively charged Nafion membrane at the front of the DGT device which slowed the diffusion of the negatively charged Asv species (H₂AsO₄₂ ⁻) considerably, relative to the uncharged AsIII species (H₃AsO₃). The effect that pH, anions, and cations may have on the selective accumulation of AsIII, in the presence of Asv, was investigated. DGT devices without a Nafion membrane and with a Nafion membrane were deployed in natural waters to determine the total inorganic As and AsIII> concentrations, and to evaluate its performance. A preliminary investigation of the coupling of a microcolumn of Chelex-100 resin with a standard electrothermal atomic absorption spectrometer was undertaken to establish its value as a laboratory-based speciation method. This involved the examination of various microcolumn materials to accommodate the Chelex-100 resin, and finding an appropriate buffer that could be used to buffer the Chelex-100 resin without interfering with the ETAAS measurement. Furthermore, factors that may affect the uptake of metal by the Chelex-100 resin, such as concentration of buffer in solution, ionic strength, and conditioning of the Chelex-100 resin, were investigated.

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  • Mapping first semester challenges : first-year students making sense of their teaching and learning environments

    van der Meer, Jacques (2008)

    Doctoral thesis
    University of Otago

    This thesis investigates first-year students' challenges in making sense of the learning and teaching environment during their first semester at university. The aims for the research are threefold. Firstly, mapping the range of challenges students at one university faced in their learning and teaching environments in the first semester. Secondly, developing a greater understanding of those challenges. Thirdly, identifying what educational initiatives the university could consider that might assist students to meet those challenges. The challenges were examined in the context of changes in higher education. My interest and motivation for this research project concerns improved practices in the first-year teaching and learning environment, rather than improved students. This means that I did not look for deficits within students, but for indications of what helps or does not help students' introduction to the new environment of academia. By mapping students' challenges in the first semester, I hope to contribute to the understanding of academic staff of the range of challenges students have to deal with. The interpretation of the results and my line of argument are partly influenced and shaped by the theoretical framework of academic literacies, and the notion of de-familiarisation. For this project, two data sources were used. The first source was data from a survey carried out in May 2004 amongst students enrolled in 100-level courses. The second source was data from interviews conducted with first-year students in the same year. In considering the analysis as a whole, a number of key issues could be discerned. These related to communication, academic skills, access to resources and help, and engagement and connection. The results showed that some of these issues had less to do with educational practices, and more to do with contested understandings of the nature of university education, and the nature of students now entering university. I argue that underlying these issues there are contentious questions of who should adjust or adapt to whom: students to the university, or the university to students? Students' reported experiences further suggest that some teachers seemed more aware than others that first-year students face particular challenges. Students did not consider their experiences as reflective of the university as a whole. The university was experienced as an institution with divergent ways of organising courses, of valuing aspects of university learning, and of interpreting seemingly similar things. This suggests that where students experienced challenges, these were not necessarily a function of students' characteristics, or students' attitudes to studying, but of particular course environments. The overall picture that presents itself, then, is that there are challenges that could be considered unnecessary. Whereas few students would experience all of the challenges identified in the results chapters, I argue that there are some aspects that warrant improvement. Improvement initiatives in first-year education, however, are not necessarily considered important by all academic staff. This is another contested issue in universities. A more explicit introduction of first-year students to academia as a range of heterogeneous communities would respond to first-year students' needs for familiarisation and clarity, as well as reflect some of the values that universities could be said to espouse. Successful interventions in first-year education, however, will also depend on ongoing dialogue with staff about various contested issues, the changed and changing context of higher education, and related challenges and opportunities.

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  • Hybridisation, and the Conservation of the Grey Duck in New Zealand

    Muller, Wiebke (2008)

    Doctoral thesis
    University of Canterbury Library

    Hybridisation is increasingly acknowledged as a conservation problem. The widespread hybridisation between grey duck (Anas superciliosa) and mallard (A. platyrhynchos) in New Zealand is a good example of a native species hybridising with a foreign one, and forms the main focus of this thesis. Mallards were introduced into New Zealand from Europe, and hybrids were soon observed. I surveyed the extent of the hybridisation on the West Coast of the South Island and found that, based on phenotype, at least half of population is now hybrids. Mallards and mallard-like hybrids dominate in the eastern South Island, while grey ducks occur only in some areas of the West Coast. Comparison with historical data suggests that the decline of the grey duck and the spread of hybrids has not stabilised and is ongoing. Contrary to expectations most grey ducks were found on agricultural land and most mallards on natural lakes or rivers, so grey ducks probably do not have an advantage over mallards on the less developed West Coast. An alternative theory is proposed here that explains the spatial distribution of hybridisation as a reflection of a temporal pattern. As mallards were first released in the east, the delay taken to cross the Southern Alps could also explain the pattern observed. This hypothesis suggests that the grey duck will persist in the southern West Coast. An analysis of the phenotypes of partners in pairs suggests that mating is positively assortative within each species and within hybrids. In fact, not a single pair of pure grey duck mated with pure mallard was observed in almost a thousand pairs, raising the question of how hybridisation started. There was a tendency for males to be more mallard-like in phenotype than their partners, suggesting there might be a selective advantage to the mallard male phenotype. This may be one factor explaining the dominance of mallards in the hybrid swarm. To analyse hybridisation at the genetic level, I analysed samples from grey ducks, mallards and domestic ducks with 11 microsatellite loci. This genotyping profile was then compared to ducks captured and shot in New Zealand. Genetic analysis confirms that the ducks in New Zealand were almost exclusively of hybrid origin. Phenotypic hybrid scores correlated with the established genotypic scores, but the correlation was imperfect, suggesting inaccuracies in either or both measures. As the spread of hybrids might be due to the differences in their fitness relative to either parent species, I compared the relative fitness of hybrid ducks using a range of health-related measures such as ecto- and endoparasite loads, immunocompetence, body condition, and heterophil to lymphocyte ratios. Overall, I found no conclusive evidence for any differences between grey duck-like and mallard-like individuals. However, as my sample consisted nearly entirely of hybrids, it is possible that fitness may differ from the parental species. To understand the outcome of hybridisation between two species, I next constructed a mathematical model to simulate hybridisation, and which allowed the specification of parameters describing mating patterns, differential survival, and differential reproductive output. The model successfully predicted the outcomes of two known hybridisation cases. In a sensitivity analysis for mallard and grey duck, the model predicted that this species pair is likely to hybridise under any set of conditions likely to be encountered across their shared range. Finally, in a study within the more general context of hybridisation, the influence of inbreeding on hybridisation rates was investigated using inbred and outbred lines of Drosophila species. I found evidence for increased hybridisation in inbred lines, and although further studies are needed to confirm the generality of this pattern, my results have implications for the management of hybridisation, and for the use of hybridisation as an adaptive strategy. In conclusion, my work suggests it is very likely that the grey duck will become extinct as a separate species in New Zealand in the near future, and that it is likely to be threatened in other areas of its range were it co-occurs with the mallard. The options for management of this situation are limited, as large areas without mallards are lacking. Captive breeding, or the management of grey duck populations on isolated islands appear the only feasible options. It seems unlikely that hybridisation can be reversed on the mainland, and a homogenous hybrid population is likely to eventually occupy the entire range of the grey duck across New Zealand.

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  • Music Publishing in London From 1780 to 1837 as Reflected in Music Publishers' Catalogues of Music for Sale: A Bibliography and Commentary.

    An, Yu Lee (2008)

    Doctoral thesis
    University of Canterbury Library

    This study documents and analyses the music-selling and publishing industry in London from 1780 to the end of the Georgian period as reflected in publishers' catalogues of music for sale. It assembles the histories and activities of these music publishers in relation to the society they served. Catalogues inform us quite precisely not only of the activities of music publishers, but also the role they played in accommodating, influencing, expanding and educating the contemporary musical taste. In addition, catalogues provide documentary evidence of compositions in issues no longer extant, and even of some works themselves at least by the lesser-known composers. Nearly 600 catalogues in over 1100 states, issued by over 100 London music-publishing firms from 1780 to 1837 have been gathered from the British Library, London; the Bodleian Library, Oxford, and Cambridge University Library, Cambridge. Arguably, publishers' catalogues are among the sharpest yet least appreciated mirrors of changes in musical taste. This study attempts to bring them into the foreground, place them in their proper historical perspective and establish their role in musicological research.

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  • Rheology of the Alpine Fault Mylonite Zone: deformation processes at and below the base of the seismogenic zone in a major plate boundary structure

    Toy, Virginia (2008)

    Doctoral thesis
    University of Otago

    The Alpine Fault is the major structure of the Pacific-Australian plate boundary through New Zealand’s South Island. During dextral reverse fault slip, a dominant slip. Formation of this highly-oriented fabric would have led to significant geometric softening and enhanced strain localisation. During this high strain deformation, pre-existing Alpine Schist fabrics in polyphase rocks were reconstituted to relatively well-mixed, finer-grained aggregates. As a result of this fabric homogenisation, strong syn-mylonitic object lineations were not formed. Strain models show that weak lineations trending towards ~090 degrees and kinematic directions indicated by asymmetric fabrics and CPO pattern symmetry could have formed during pure shear stretches up-dip of the fault of ~ 3.5, coupled with simple shear strains, gamma >=30. The preferred estimate of simple:pure shear strain gives a kinematc vorticity number, Wk>=0.9997. Rapid exhumation due to fault slip resulted in advection of crustal isotherms. New thermobarometric and fluid inclusion analyses from fault zone materials allow the thermal gradient along an uplift path in the fault rocks to be more precisely defined than previously. Fluid inclusion data indicate temperatures of 325±15 degrees C were experienced at depths of ~ 4.5 km, so that a high thermal gradient of ~75 degrees C/km is indicated in the near-surface. This gradient must fall off to -slip quartz CPO fabrics indicate deformation temperatures did not exceed 650 degrees C at >=7.0-8.5±1.5 kbar, ie. 26-33 km depth. During exhumation, the strongly oriented quartzite fabrics were not favourably oriented for activation of the lower temperature basal slip system, which should have dominated at depths 25μm, indicating maximum differential stress of ~55 MPa for most mylonites). It is likely that the preferentially oriented prism slip system was activated during these events, so the Y-maximum CPO fabrics were preserved. Simple numerical models show that activation of this slip system is favoured over the basal system, which has a lower critical resolved shear stress (CRSS) at low temperatures, for aggregates with strong Y-maximum orientations. Absence of pervasive crystal-plastic deformation of micas and feldspars during activation of this mechanism also resulted in preservation of mineral chemistries from the highest grades of mylonitic deformation (ie. amphibolite-facies). Retrograde, epidote-amphibolite to greenschist-facies mineral assemblages were pervasively developed in ultramylonites and cataclasites immediately adjacent to the fault core and in footwall-derived mylonites, perhaps during episodic transfer of this material into and subsequently out of the cooler footwall block. In the more distal protomylonites, retrograde assemblages were locally developed along shear bands that also accommodated most of the mylonitic deformation in these rocks. Ti-in-biotite thermometry suggests biotite in these shear bands equilibrated down to ~500±50 degrees C, suggesting crystal-plastic deformation of this mineral continued to these temperatures. Crossed-girdle quartz CPO fabrics were formed in these protomylonites by basal dominant slip, indicating a strongly oriented fabric had not previously formed at depth due to the relatively small strains, and that dislocation creep of quartz continued at depths =0.98), but require a similar total pure shear component. Furthermore, they indicate an increase in the simple shear component with time, consistent with incorporation of new hanging-wall material into the fault zone. Pre-existing lineations were only slowly rotated into coincidence with the mylonitic simple shear direction in the shear bands since they lay close to the simple shear plane, and inherited orientations were not destroyed until large finite strains (<100) were achieved. As the fault rocks were exhumed through the brittle-viscous transition, they experienced localised brittle shear failures. These small-scale seismic events formed friction melts (ie. pseudotachylytes).The volume of pseudotachylyte produced is related to host rock mineralogy (more melt in host rocks containing hydrated minerals), and fabric (more melt in isotropic host rocks). Frictional melting also occurred within cataclastic hosts, indicating the cataclasites around the principal slip surface of the Alpine Fault were produced by multiple episodes of discrete shear rather than distributed cataclastic flow. Pseudotachylytes were also formed in the presence of fluids, suggesting relatively high fault gouge permeabilities were transiently attained, probably during large earthquakes. Frictional melting contributed to formation of phyllosilicate-rich fault gouges, weakening the brittle structure and promoting slip localisation. The location of faulting and pseudotachylyte formation, and the strength of the fault in the brittle regime were strongly influenced by cyclic hydrothermal cementation processes. A thermomechanical model of the central Alpine Fault zone has been defined using the results of this study. The mylonites represent a localised zone of high simple shear strain, embedded in a crustal block that underwent bulk pure shear. The boundaries of the simple shear zone moved into the surrounding material with time. This means that the exhumed sequence does not represent a simple ‘time slice’ illustrating progressive fault rock development during increasing simple shear strains. The deformation history of the mylonites at deep crustal P -T conditions had a profound influence on subsequent deformation mechanisms and fabric development during exhumation.

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  • Covalent Attachment of Nanoscale Organic Films to Carbon Surfaces.

    Yu, Samuel Shing Chi (2008)

    Doctoral thesis
    University of Canterbury Library

    Modification of planar graphitic carbon surfaces by the attachment of molecular films has been investigated in this work. Molecular layers have been grafted to glassy carbon (GC) and pyrolyzed photoresist film (PPF) by employing a range of techniques, which involved electrochemically and photochemically assisted procedures. Modification methods involve the electrochemical reduction of aryldiazonium salt, electrochemical oxidation of arylcarboxylate and photolysis of alkene, alkyne and azide on carbon surfaces. For these methods, it is proposed that reactive species are generated by the procedures, which leads to the grafting of modifiers to the carbon surfaces. A selection of molecular species was grafted to GC and PPF by these method containing different terminal R-functional groups that include —COOH, -NO₂, -NH₂, and —NCS. The grafted R-functional groups permit for further chemical reactions on the surface. Electrochemically and photochemically grafted films were examined with a combination of water contact angle measurements, cyclic voltammetry, X-ray electron spectroscopy XPS, optical microscopy, scanning electron microscopy SEM and atomic force microscopy AFM. Film properties such as surface concentration, film thickness, wettability, chemical composition and reactivity were characterized by the above mentioned techniques. Films electrochemically prepared from aryldiazonium salts and arylcarboxylates, under the conditions applied in this work, formed loosely packed multilayers with typical film thicknesses of les than 5 nm. Photochemically grafted films prepared from alkenes and azides, in general, formed loosely packed monolayers with film thicknesses of less than 2 nm. Loosely packed multilayers were also prepared from alkene and alkyne by photochemical procedures. ii Chemical reactions on grafted films were demonstrated and analyzed by a combination of the above mentioned characterization techniques. In particular, the reduction of nitrophenyl (NP)films, amine-coupling reactions, photoactivation of grafted films with oxalyl chloride and electrostatic assembly of anionic gold nanoparticles were investigated. Selected chemical reactions permitted identification and evaluation of the grafted layers, and demonstrated the ability to control the immobilization of chemical species. Microscale chemical patterning of two different types of modifiers on carbon surfaces was demonstrated using photolithographical techniques that utilized photochemical reactions with azides. Patterns of line-arrays with line widths of hundreds of micrometers to 10 µm were formed.

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  • Social Exclusion, Self-Esteem, & Mating Relationships: Testing a Domain-Specific Variant of Sociometer Theory

    Kavanagh, Phillip Sean (2008)

    Doctoral thesis
    University of Canterbury Library

    Sociometer Theory (Leary & Downs, 1995; Leary, Tambor, Terdal, & Downs, 1995) proposes that state self-esteem is a gauge of social inclusion. Expansions to this theory by Kirkpatrick and Ellis (2001) suggest that this is a domain specific process with different sociometers for different adaptive domains. Two studies were conducted to test predictions derived from the domain specific sociometer model of self-esteem proposed by Kirkpatrick and Ellis (2001). In Study 1, participants (N = 83) who were currently single, received feedback to indicate either acceptance (inclusion) or rejection (exclusion) for a potential dating situation. The results indicated that participants who were accepted versus rejected reported increases in state self-esteem and higher mating aspirations. The same effects were not present for either friendship aspiration or friendship investment, indicating domain specificity. The effect of the manipulation on mating aspirations was also significantly mediated by state self-esteem. Study 2 replicated Study 1 using participants (N = 81) who were currently in an intimate relationship. The results indicated that participants who were accepted versus rejected reported increases in state self-esteem and decreases in perceived relationship quality (commitment and satisfaction). The same effects were not present for either friendships aspirations or friendship investment. The association between the manipulation and resulting changes in perceived relationship quality were significantly mediated by state self-esteem, with state self-esteem acting as a suppressor. The results from both studies support a domain-specific conceptualisation of sociometer theory.

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  • High-voltage partial-core resonant transformers

    Bell, Simon Colin (2008)

    Doctoral thesis
    University of Canterbury Library

    This thesis first describes the reverse method of transformer design. An existing magnetic model for full-core shell-type transformers, based on circuit theory, is summarised. A magneto-static finite element model is introduced and two sample transformers are analysed. The magnetic model based on finite element analysis is shown to be more accurate than the model based on circuit theory. Partial-core resonant transformers are then introduced and their characteristics are explained using an equivalent circuit model. A method of measuring the winding inductances under resonant operation is developed and used to investigate the characteristics of two different tuning methods. A finite element model of the partial-core resonant transformer is developed by adopting the model for full-core shell-type transformers. The model results accurately match the measured inductance variation characteristics of three sample transformers and predict the onset of core saturation in both axial-offset and centre-gap arrangements. A new design of partial-core resonant transformer is arrived at, having an alternative core and winding layout, as well as multiple winding taps. The finite element model is extended to accommodate the new design and a framework of analysis tools is developed. A general design methodology for partial-core resonant transformers with fixed inductance is developed. A multiple design method is applied to obtain an optimal design for a given set of specifications and restrictions. The design methodology is then extended to devices with variable inductance. Three design examples of partial-core resonant transformers with variable inductance are presented. In the first two design examples, existing devices are replaced. The new transformer designs are significantly lighter and the saturation effects are removed. The third design example is a kitset for high-voltage testing, with the capability to test any hydro-generator stator in New Zealand. The kitset is built and tested in the laboratory, demonstrating design capability. Other significant test results, for which no models have yet been developed, are also presented. Heating effects in the core are reduced by adopting an alternative core construction method, where the laminations are stacked radially, rather than in the usual parallel direction. The new kitset is yet to be used in the field.

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  • Spectroscopic mode identification in a sample of non-radially pulsating stars

    Wright, Duncan John (2008)

    Doctoral thesis
    University of Canterbury Library

    This thesis has analysed spectroscopic data for three stars in detail, the β Cephei star V2052 Ophiuchus, the γ Doradus star QW Puppis and the γ Doradus candidate star HD139095. Twelve other candidate γ Doradus stars have had their Vrotsin i, binary status and, where possible, the presence of line profile variation determined. A new technique utilising scaled delta functions has been developed to allow the extraction of a single, high S/N line profile from a high resolution and large wavelength range spectrum. This procedure has performed well in the γ Doradus stars examined. The application of the new mode identification technique, the Fourier Parameter Fit method, to the three stars examined in detail has been very successful. For each of the three stars constraints have been placed on the degree (l) and the azimuthal order (m) of the non-radial pulsation modes detected.

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  • Actinomycetes and fungi associated with marine invertebrates: a potential source of bioactive compounds

    Mahyudin, Nor Ainy (2008)

    Doctoral thesis
    University of Canterbury Library

    Actinomycetes and fungi were successfully isolated from both New Zealand and Malaysian marine invertebrates and classified as facultatively marine based on their ability to grow on both sea water and non-sea water media. Most of the extracts obtained from selected isolates were cytotoxic. A clear preference of the actinomycetes for solid-state fermentation was observed, however, for fungi no significant preference was seen. Three isolates of Streptomyces spp., four Penicillium spp. and two Paecilomyces spp. whose extracts showed good cytotoxicity were selected for further investigation. A small-scale extract obtained from a solid culture of Streptomyces sp. (LA3L2) showed good cytotoxicity and a new cytotoxic metabolite was isolated from a large-scale extract of Streptomyces sp. (LA3L2). This metabolite was characterized as S-methyl 2,4-dihydroxy-6-isopropyl-3,5-dimethylbenzothioate (5.15) and is only the third compound reported to contain the S-methyl benzothioate group. Two known compounds, montagnetol (5.16) and erythrin (5.18), were isolated from a further large-scale cultivation of Streptomyces sp. (LA3L2) and is the first reported actinomycete to produce these lichen-related compounds. In addition, two known inactive metabolites (bohemamine (5.1) and bohemamine B (5.2)) were identified from the small-scale extract. Streptomyces sp. (LA3L2) was also investigated for the effect of temperature and salinity on growth and cytotoxicity and shown to produce bohemamine only at 20 - 28℃ and 4% sea salt concentration on solid media. This isolate gave a low yield of active metabolite under all conditions. Small-scale extracts of two other Streptomyces spp. yielded three known cytotoxic metabolites. These were thiazostatin B (7.14) from Streptomyces sp. (LA5L4) and chromomycin A2 (7.1), chromomycin A3 (7.2) and chromomycin 02-3D (7.3) from Streptomyces sp. (LA3L1). All four Penicillium spp. produced known metabolites. Penicillium sp. (LY1L5) yielded two known metabolites, cycloaspeptide A (7.4) and α-cyclopiazonic acid (7.5). α-Cyclopiazonic acid (7.5) and three other known metabolites (roquefortine A (7.6), cyclopeptin (7.7) and viridicatin (7.8)) were isolated from Penicillum sp. (KK3T23). Penicillium sp. (KK3T8) produced brefeldin A (7.10), while mycophenolic acid (7.12) and brevianamide A (7.11) were produced by Penicillium sp. (KK4T14b). The effect of salinity on growth and cytotoxicity was investigated for the two Penicillium isolates producing the cytotoxic metabolite, α-cyclopiazonic acid (7.5). Saline conditions were not required for growth but metabolite production differed between the two isolates with respect to salinity. Isolate LY1L5 required saline conditions for α-cyclopiazonic production whereas isolate KK3T23 produced the metabolite under non-saline conditions and in concentrations of sea salt up to 6%. Three known compounds, indole-3-carboxylic acid (7.15), indole-3-carboxylate (7.17) and 5-carboxymellein (7.16) were identified from Paecilomyces sp. (PR5L9). Investigation of a small-scale extract obtained from a solid culture of another Paecilomyces sp. (PR10T2) resulted in the isolation and characterization of a unique structure of a symmetrical cyclic depsipeptide, epi-angolide (NAM 6-1). NAM 6-1 was considered as a new compound based on four homoisomeric configurations (A1, A2, A3 and A4). The value of dereplication procedures with respect to the rapid identification of metabolites and enhancement of in-house metabolite libraries is discussed. Structural elucidation of nine known metabolites (7.1, 7.2, 7.3, 7.5, 7.6, 7.7, 7.8, 7.10 and 7.11) was greatly aided by the in-house dereplication techniques using LC-MS-UV and AntiMarin database. A significant advantage was gained by the use of the CapNMR which enabled NMR characterization of very small quantities of metabolites (<5 µg of materials were required to perform 1D proton NMR experiments for the dereplication of seven known compounds; bohemamine (5.1), bohemamine B (5.2), thiazostatin B (7.14), indole-3-carboxylate (7.17) and 5-carboxymellein (7.16). Approximately 20 µg of materials were needed to acquire 1D and 2D (HSQC, HMBC and NOE) NMR spectra for structural elucidation of the new metabolite, S-methyl 2,4-dihydroxy-6-isopropyl-3,5-dimethylbenzothioate (5.15). Some 8 µg of materials were sufficient to perform 1D and 2D (COSY, HSQC and HMBC) NMR experiments for complete structural characterization of two known metabolites, montagnetol (5.16) and erythrin (5.18). Approximately 10 µg of materials were needed to acquire 1D and 2D NMR (COSY, HSQC and HMBC) experiments for structural elucidation of the new compound, epi-angolide NAM 6-1 (A1, A2, A3 and A4). Rapid identification of known fungal metabolites enabled the in-house HPLC-UV/Rt library to be enhanced by eight metabolites (7.5, 7.6, 7.7, 7.8, 7.10, 7.11, 7.17 and 7.16). An HPLC-UV/Rt library for actinomycete metabolites was successfully established with the insertion of eight known metabolites (5.1, 5.2, 5.16, 5.18, 7.1, 7.2, 7.3 and 7.14).

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  • Technologies for tissue preservation: the role of endogenous and exogenous antioxidants in preserving tissue function in chinook salmon, Oncorhynchus tshawytscha

    Tuckey, Nicholas Pierre Lemieux (2008)

    Doctoral thesis
    University of Canterbury Library

    The seafood industry is of considerable importance to both the New Zealand and global economies and therefore tissue preservation technologies that increase product quality and/or prolong shelf life have the potential to add significant value. Technologies for maintaining the viability of isolated tissues also have a wide range of other medical and industrial applications. This thesis examines the relationship between metabolic function, oxidation and cell death and the resulting stability of the non-viable tissues during long term storage in chinook salmon (Oncorhynchus tshawytscha) red and white skeletal muscle tissue. This research also looks at the role of the aquatic anaesthetic AQUI-S™, in which the active ingredient is isoeugenol (a lipid soluble antioxidant), and other antioxidant compounds in preserving metabolic function in viable tissues and tissue stability in nonviable tissues. Perfusion of salmon tails at 15℃ over 5 or 10 hours with oxygen saturated saline resulted in significant increases in protein and lipid oxidation (protein carbonyl and TBARS concentrations respectively) in the red muscle, but not the white muscle. The introduction of ascorbic acid and uric acid into the saline did not reduce the oxidation in the red muscle despite significantly increasing their respective concentrations in the tissue. This indicates the difficulties associated with attempting to extend tissue viability by delivering free oxygen to the tissue and also highlights the difference in susceptibility of the two muscle types to oxidation. Tail fillets from salmon harvested in both rested and exhausted physiological states using AQUI-S™, and fillets from exhausted salmon harvested without AQUI-S™, were exposed to air at 15℃ for up to 96 hours. Protein carbonyls increased in a roughly linear fashion over the entire 96 hours in all three groups. Both lipid peroxides (TBARS) and uric acid concentrations began to increase in the exhausted group after 30 hours. In contrast, no significant increases in lipid peroxides or uric acid was seen in the fillets from either group harvested using AQUI-S™. Vitamin E concentrations reduced slowly but did not change significantly despite the oxidation that was evident in the tissue. These processes also occurred in salmon tail fillets during storage at 6℃. The measurement of ATP related compounds provides an effective indicator of both the metabolic state of the tissue post-harvest and the quality. The breakdown of these compounds is also associated with the production of ammonia and hydrogen peroxide. Fresh rested salmon fillets had high concentrations of ATP and creatine phosphate, which were both depleted after 12 hours storage at 15℃. This indicates that cell viability lasted a number of hours following harvesting. These metabolites were depleted in exhausted fillets and metabolic potential appeared to be immediately compromised. The concentration of the taste enhancing compound IMP was significantly reduced in fresh rested tissue, but increased during storage, and was significantly higher than in exhausted tissues following 12 hours of storage at 15℃. This indicates that some properties of rested tissues may improve with limited storage times. The accumulation of uric acid - the metabolic end point for ATP related compounds - was also significantly reduced in rested tissue and increases in K-value were slowed. AQUI-S™ showed an ability to preserve tissue function through its anaesthetic action allowing tissue to be harvested in a rested state, and to reduce late stage lipid oxidation in stored salmon tail fillets. The antioxidant action of isoeugenol in salmon fillets may be mediated through its ability to chelate transition metals released during tissue degradation. This research shows that during reperfusion and during fillet storage there is a significant level of oxidative stress, which needs to be minimized while maintaining basic tissue metabolism to prolong tissue and cellular viability. The development of future technologies to preserve tissue viability may depend on the development of a synthetic oxygen carrying compound with properties similar to red blood cells. This may allow more control over oxygen delivery, potentially reducing the oxidative stress associated with high concentrations of free oxygen in solution. However, preserving cell viability will also require the maintenance of endogenous antioxidant function and there is also the potential to use iron chelating compounds including plant derived flavonoids to preserve non-viable tissues. Future research in these areas is necessary.

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  • Compactness Under Constructive Scrutiny

    Diener, Hannes (2008)

    Doctoral thesis
    University of Canterbury Library

    The aim of this thesis is to understand the constructive scope of compactness. We show that it is possible to define, constructively, a meaningful notion of compactness in a more general setting than the uniform/metric space one. Furthermore, we show that it is not possible to define compactness constructively in a topological space. We investigate exactly what principles are necessary and sufficient to prove classically true theorems about compactness, as well as their antitheses. We develop beginnings of a constructive theory of differentiable manifolds.

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  • Treatment Outcome, Risk Assessment, and Recidivism among Sexual Offenders against Children

    Beggs, Sarah Marie (2008)

    Doctoral thesis
    University of Canterbury Library

    The sexual abuse of children is an issue that society must address with urgency and commitment, given the profoundly damaging effects and widespread occurrence of this kind of crime. Providing psychological treatment to identified offenders is an important endeavour of the criminal justice system, with the aim of reducing recidivism and thereby preventing future victims. This dissertation explores a number of areas relevant to the treatment of sexual offenders on a sample of 223 adult males who completed a prison-based programme for child sexual offenders in New Zealand. Specifically, the assessment of treatment outcome and its relationship with recidivism, risk assessment, and the influence of specific offender factors on estimates of treatment outcome and risk were investigated. Study 1 (N = 218) is an independent validation of the validity of the Violence Risk Scale: Sexual Offender Version (VRS:SO; Olver, Wong, Nicholaichuk, & Gordon, 2007), a recently developed risk assessment instrument for sexual offenders that incorporates both static and dynamic risk factors and contains protocols for the assessment of change as a result of treatment. Results indicate support for the inter-rater reliability, concurrent validity, and predictive validity of the VRS:SO with regard to sexual recidivism, with pre-treatment and post-treatment scores showing superior predictive validity relative to a widely used measure of static risk (Static-99; Hanson & Thornton, 1999) and a measure of "Deviance" based on a 4-factor battery of relevant psychometric tests (Allan, Grace, Rutherford, & Hudson, 2007). In Study 2 (N = 218), three separate methods of assessing proximal treatment outcome (representative of three categories of treatment outcome measures that have previously been applied in the literature) are applied and compared in terms of their predictive validity with regard to sexual recidivism, and the relative advantages and disadvantages of their use. These measures are: change on a battery of relevant psychometric tests administered prior to and following treatment; change across treatment on the VRS:SO; and post-treatment ratings of the attainment of treatment goals as measured by a modified version of Hogue’s (1994) Standard Goal Attainment Scaling for Sexual Offenders (SGAS). Results indicate that positive treatment outcomes as measured by all of these methods are associated with reduced sexual recidivism. SGAS scores are identified as being relatively simple and efficient to obtain, however the VRS:SO and the psychometric battery are both able to provide useful pre-treatment clinical information regarding potential treatment targets for a particular offender. Study 3 (N = 223) and Study 4 (N = 216) are explorations of the influence of particular offender characteristics on response to treatment and risk of recidivism. Of particular interest was the personality construct of psychopathy (measured using the Psychopathy Checklist-Revised, PCL-R; Hare, 1991), and both studies are attempted replications and extensions of previously reported interaction effects involving this construct (Heilbrun, 1979; Seto & Barbaree, 1999). The results of Study 3 indicate that there is no interaction effect between PCL-R scores and treatment outcome (as measured by the SGAS) on sexual recidivism, in contrast to an influential study by Seto and Barbaree (1999). Study 4 reports an interaction effect between PCL-R scores and intelligence on recidivism, such that higher than average IQ scores appear to moderate the well-known association between psychopathy and risk. Overall, the findings reported in this dissertation suggest the importance of considering dynamic factors as well as static factors in sex offender risk assessments, and support the premise that dynamic factors are changeable, with change being associated with changes in recidivism. The potential for certain offender characteristics to influence treatment response and risk of recidivism is highlighted, and several areas for further exploration are identified.

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  • Multi-Species Interactions in Weed Biocontrol: Carduus nutans as a Case Study

    Groenteman, Ronny (2008)

    Doctoral thesis
    University of Canterbury Library

    Classical biocontrol systems are sometimes treated as an exercise in community assembly. As such, they include multiple species interactions. This thesis explores multi-species aspects in classical weed biocontrol, using thistles as a case study. The abundance, phenology and impact of three biocontrol agents were followed on their target host, Carduus nutans L. and are described, for the first time in New Zealand for two of them (Urophora solstitialis L. and Trichosirocalus horridus sensu (Panzer)). Composition in New Zealand of the recently revised Trichosirocalus weevil species complex was surveyed nation-wide. One species only was found, albeit exhibiting a wider host range than anticipated from the published revision. Interspecific interactions and individual and combined effect of multiple biocontrol agents on C. nutans were tested in cage setups; the effect on the weed population was then estimated by manipulations of an existing matrix population model for this weed in New Zealand. The potentially better seed predator (U. solstitialis) was outcompeted by the worse seed predator (Rhinocyllus conicus (Froehlich)) which has similar niche preference. Urophora solstitialis was also adversely impacted by the crown-root feeder (T. horridus). Trichosirocalus horridus affected C. nutans survival, even at the medium density used, and significantly reduced potential seed production by 33%; in field densities, T. horridus is likely to affect C. nutans even more. Urophora solstitialis was estimated to destroy about 28% of the remaining seed in the absence of the other agents, and about 17% in the presence of T. horridus. The estimated combined effect of T. horridus and U. solstitalis on C. nutans population growth rate was greater than the effect of either agent alone. In the face of growing weed invasions, multiple thistle species were used to test ‘multi-targeting’ as a novel approach to target groups of ‘sleeper weeds’. Both in a field experiment and in a field survey, the seed predator R. conicus was found to attack and damage some ‘non-target’ thistle species more in the presence of the target species (C. nutans) than in its absence; however, levels of attack on non-target species were always modest. The ultimate goal of biocontrol is to reduce weed populations. A field survey revealed that current population densities of multiple thistle species in Canterbury are not obviously lower than in the mid 1980s, when only R. conicus was present. This may be because successful biocontrol has reduced the management input required to maintain the same thistle density.

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  • The Impact Of Water Content And Other Environmental Parameters On Toluene Removal From Air In A Differential Biofiltration Reactor

    Beuger, Abraham Laurens (2008)

    Doctoral thesis
    University of Canterbury Library

    In this work, a differential reactor was used to expose all the biofilter packing material (compost) to a uniform toluene concentration in air. The reactor was combined with water content control using the suction cell principle and traditional inlet concentration, temperature and humidity control. The matric potential was controlled using the suction cell principle between -5 to -300 cm H₂O which controlled the water content between 0.99 and 2.30 g g⁻¹ (dry weight). Two types of compost were used, with different water retention curves with no observed difference in elimination capacity. The elimination capacity varied between 2.7 g m⁻³r hr⁻¹ and 21 g m⁻³r hr⁻¹ with low potential causing low removal rates. The reduction in EC at low matric potentials was attributed to several factors: loss of water availability to the organisms, water redistribution in the medium, non-adaptable micro-organisms, and reduced mass transfer. Cultures isolated from compost were used to inoculate the reactor to create a biofilm. A maximal observed surface EC of is 0.17 g m⁻²r hr⁻¹ and a specific removal rate of 1250 g m⁻³b hr⁻¹ is measured. These values were used in modelling the biofilter performance. The EC was dependent on the residual toluene concentration. The EC increased with increasing toluene concentration until reaching a critical concentration. Above this concentration, 100 – 300 ppm (0.37- 1.11 g m⁻³) depending on biofilm thickness and area of coverage, the EC was constant. Three toluene dependency curves were fitted using a zero order and a composite model using a weighted average of a zero and first order component. From the data the critical concentration (Ccrit) and the ECcrit was found and used to determine the biofilm thickness. It was estimated to be between 68 and 134 µm. Using a qmax of 1250 g m⁻³b hr⁻¹ and optimising the model a Ks of 1.3•10⁻¹ g m⁻³g was found. This was comparable to values found in the literature. There was no significant difference in the fit between both models. The Ks was low compared to the majority of the data, which means that the zero order part of the composite model dominated. Nitrogen and other nutrients were added to investigate their influence on the elimination capacity (EC) of toluene. Also the effect of temperature on the EC was investigated between 14 and 60 °C. Maximal removal rates were found between 25 and 55 °C. The EC decreased by 90% going from 55 to 60 °C and took many weeks to recover. Without any extra nitrogen added to the media, the EC averaged around 6 ± 0.3 g m⁻³r h⁻¹. Although the average EC was lower than most reports for toluene removal, it was still in the general range reported. When NH4Cl (1 g l⁻¹) was added to the reactor, the EC increased to 41 ± 1.7 g m⁻³r hr⁻¹. Similar effects were observed with nitrate addition; the steady state EC doubled from 30.1 ± 0.9 g m⁻³r hr⁻¹ to 76.3 ± 2.5 g m⁻³r hr⁻¹. Other macronutrients tested like phosphate, sulphate, magnesium, calcium and iron did not increase the EC.

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  • The Role of Actin in Hyphal Tip Growth

    Suei, Sandy H.Y. (2008)

    Doctoral thesis
    University of Canterbury Library

    This thesis investigates whether there are alternative mechanisms of tip growth in invasive and non-invasive hyphae of the fungus Neurospora crassa. The cytoskeleton protein actin is thought to play a pivotal role in hyphal tip growth, performing a multitude of tasks, one of which may be the provision of a resistive force to counter turgor pressure. An Actin depleted zone (ADZ) was the dominant feature of invasive hyphal tips, which was largely absent from non-invasive hyphae. The Spitzenkörper was slightly larger in invasive hyphae but this size difference alone was thought insufficient to account for the exclusion of filamentous actin (F-actin) from the tip. The actin nucleating protein formin was found at sites where actin nucleation is occurring, while cofilin, a protein that severs F-actin, was found to localise where F-actin disassembly was likely to be occurring. It is suggested that these proteins are likely to play a role in controlling a dynamic cytoskeleton, rearrangements of which are required for the two modes of growth. Invasive hyphae were found to generate a higher turgor than non-invasive hyphae. These results suggest that the F-actin rearrangements facilitated by cofilin give an ADZ that may play a role in invasive hyphal tip growth; possibly through a reduction of tip resistance; thus enabling the provision of a greater protrusive force by turgor.

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  • The effect of population bottleneck size on parasitic load and immunocompetence of introduced birds in New Zealand

    Allen, Sophy Elizabeth (2008)

    Doctoral thesis
    University of Canterbury Library

    I investigated parasitic infection and immunocompetence in populations of introduced bird species in New Zealand (NZ) that had experienced a range of population bottlenecks (11-808 individuals), and compared these parameters to non-bottlenecked conspecifics in the United Kingdom (UK). My aims were two-fold; firstly to assess if population bottlenecks are linked to increased parasite loads and/or decreased immunocompetence, and secondly, to assess at what severity of bottleneck these effects become evident. I found that ectoparasite load (chewing lice, Order: Phthiraptera, Sub-Orders: Amblycera & Ischnocera) was significantly higher in the more severely bottlenecked species in NZ than in the UK, whilst this difference became non-significant at more moderate bottlenecks. The difference was mainly driven by the Sub-Order Amblycera. The prevalence of avian malaria (Plasmodium spp.) was significantly negatively correlated to bottleneck size within NZ, after controlling for body mass. Total leucocyte and differential lymphocyte counts were elevated in the less bottlenecked species that were infected with malaria, whilst the populations at the more severe end of the bottleneck spectrum did not exhibit such a response. Furthermore, heterophil/lymphocyte (HL) ratio (a parameter used as an indicator of environmental and/or immunological stress), was significantly raised in the more bottlenecked species when compared to their UK counterparts, and this difference was correlated with the size of the bottleneck. Immunocompetence was further assessed by the experimental challenge of six introduced birds species in NZ with the mitogen phytohaemagglutinin (PHA). Immune response to PHA was significantly correlated to bottleneck size, but in the opposite direction to that predicted; immune response was greater in the more bottlenecked species. However, this may be an indication of increased investment in immunity, due to increased parasite and pathogen pressure or differential investment in varying components of the immune system. Finally, the immune response to PHA was compared in nestlings of two species that had experienced very different bottlenecks (70 vs. 653). After controlling for ectoparasitic infestation, I found no difference between the two species; however, this finding may be confounded by interspecific competition. Overall, my findings suggest that more severe population bottlenecks may result in increased susceptibility to pathogens, and impact on the immune system. This has a number of implications for the development of conservation protocols, and future avenues of research are suggested.

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