1,066 results for Doctoral, 2015

  • Dancing to a different tune: adaptive evolution fine-tunes protein dynamics

    Donovan, Katherine Aleisha (2015)

    Doctoral thesis
    University of Canterbury Library

    The molecular mechanisms that underpin adaptive evolution are not well understood. This is largely because few studies relate evolved alleles (genotype) with their physiological changes (phenotype), which move a population to better fit its environment (adaptation). The work described in this thesis provides a case study exploring the molecular changes underlying adaptive evolution in a key allosteric enzyme. It builds upon a long-term evolution experiment by Richard Lenksi, where twelve replicate populations of Escherichia coli have adapted in parallel to better fit their low-glucose environment. I focused on the allosteric enzyme pyruvate kinase type 1, since this has been shown to adapt to this environment. First, I used X-ray crystallography to determine a higher resolution structure (2.2 Å) than previously available of the wild-type PK1 enzyme for comparison with the evolved enzymes. I resolved the ambiguous space-group problem that affects these crystals, and demonstrated that the kinetic function of the recombinant enzyme is the same as previously reported. In addition, I propose a new model for allosteric activation: a combination of structural and dynamic analyses determined that the allosteric signal is transferred by a series of dynamic changes between the allosteric site, upon fructose-1,6-bisphosphate binding, and the active site for increased substrate binding. The functional analyses demonstrated that all eight evolved PK1 enzymes have a reduced activity compared to the wild-type PK1 at physiological substrate concentrations. Not only did the evolved PK1 enzymes show a parallel decrease in activity, but they all showed changes to substrate binding affinity and seven of the eight showed an altered allosteric activation mechanism. These results suggest that natural selection has selected for enzymes with a reduced activity by altering the functional mechanism of the evolved enzymes. However, in crystal and in solution structure characterisation determined that all of the evolved PK1 enzymes have maintained the same structural fold as the wild-type PK1. Although the fold is the same, substrate binding promiscuity suggested a change in the flexibility of the enzyme, allowing substrates of different sizes and shapes to bind. Computational and experimental dynamics studies determined that natural selection has selected for reduced activity by altering the dynamics in all of the evolved PK1 enzymes, and it has used altered dynamics to change the allostery of the enzymes. Therefore, this study provides the first example of adaptive evolution fine-tuning protein dynamics to alter allostery. This thesis describes the molecular mechanisms underlying one aspect of adaptation of Escherichia coli to the low-glucose environment in Lenski’s long-term evolution experiment. The adaptive mutations in Escherichia coli’s pyruvate kinase type 1 serve to increase the availability of phosphoenolpyruvate for glucose uptake. From a molecular perspective, natural selection has selected for adaptive amino acid substitutions that produce an enzyme with reduced catalytic activity at low phosphoenolpyruvate concentrations, thus decreasing phosphoenolpyruvate consumption. In addition, the adaptive mutations have altered the enzymes’ affinity for the allosteric activator (fructose- 1,6-bisphosphate), fine-tuning them to match the concentration of fructose-1,6- bisphosphate in the cell at the point of glucose re-introduction. Overall, this work describes the intricate relationship between genetic changes and the resulting phenotype and demonstrates the parallel nature of adaptation for this particular case study. Whereby, parallel changes are mapped from organismal fitness, to enzyme function and to enzyme structure. The dynamic changes, however, are not parallel thus making the prediction of specific changes in adaptive evolution difficult.

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  • The claim of loss of self-control: some challenges of the genetic-based defence to criminal responsibility

    Bastani, Amir (2015)

    Doctoral thesis
    University of Otago

    In this thesis, I will focus on one important piece of genetic evidence, concerning the Monoamine Oxidas Acid A (MAOA) gene, unscientifically known as the ‘warrior’ gene. In 2002, a famous study by Caspi and his colleagues suggested that individuals who have one variation of MAOA, and were severely maltreated during childhood, have a greater predisposition to antisocial behaviour compared to other groups in the study. It was the first study to measure the effect of the combination of genetic and environmental factors (GxE) on the further development of antisocial behaviour. I will refer to this discovery as GxE evidence. A fundamental dispute, influenced by scientific advances such as the discovery of GxE, is the age-old philosophical schism between free will and determinism. It has been suggested that science will be able to indicate that agents’ actions are determined by their genes and the notion of free will is an illusion. That claim has alarming implications for the criminal law. The fundamental premise of criminal law is that people are responsible for the outcome of their conduct. That responsibility depends on the extent to which agents knowingly and voluntarily choose the outcome of their conduct. If science can indicate that human’s conduct, far from being knowingly and voluntarily chosen, is predetermined genetically, then considering any role for criminal responsibility must be controversial. A part of this thesis will consider the legal response to the free will/determinism debate. Setting aside the imperious challenges of science, and the free will/determinism debate, I will look at other scientific challenges which are relevant to the present categories of criminal responsibility and which can improve, but not dictate, the criminal law. Specifically, I will focus on the issue of loss of self-control. That issue has been chosen because scientific researchers have indicated that individuals’ ability to exercise their self-control is affected to some degree by GxE. There are other advances in science which trigger the issue of loss of self-control but I am looking at only GxE evidence. Loss of self-control can be considered as the basis for two defences. Firstly, loss of self-control can take the form of a claim of complete inability to control impulses. In some jurisdictions the total inability to control impulses is recognised as a full defence, called volitional insanity (V-insanity). In those jurisdictions, if an individual is unable to completely control his/her impulses, he/she is not considered criminally responsible. In stark contrast, neither New Zealand nor English law – the focus of this thesis – recognises V-insanity; they recognise cognitive insanity (C-insanity) only. C-insanity is only a defence where a person is unable to appreciate the nature – factual or moral – of his/her conduct. As a result of the non-recognition of V-insanity, if an individual is not able to control his/her impulses, and if he/she cannot establish any other defences, the person will be treated as fully criminally responsible. For the first time in New Zealand law, I will develop an argument in favour of the introduction of V-insanity as a defence. The second form of the claim of loss of self-control, which is relevant to GxE evidence, is the claim of significant impairment in controlling impulses. This is the basis for the defence of diminished responsibility (DR) as it is recognised under some common law jurisdictions such as English law. The difference between DR and V-insanity is that for V-insanity it is impossible for a person to control his/her impulses but in the case of DR it is not totally impossible for a person to control them. Instead, in the case of DR, it is seriously difficult for a person to control his/her impulses. Under English law DR, which is available only for murder charges, is a partial defence. It reduces, but does not totally exempt, a person’s criminal responsibility. However, DR is not accepted under New Zealand law and a person who has significant difficulties in controlling his/her impulses, is considered fully criminally responsible. In this thesis, building on the academic literature, I will argue that New Zealand should adopt the DR defence. Having argued that New Zealand should adopt the defence of V-insanity and DR, I will analyse GxE evidence as the basis for those defences. To date, there has been no such discussion in the scholarly discourse. It is not my aim to definitely determine whether GxE evidence as the basis for the two defences should be accepted or not. Rather, my goal is to highlight legal requirements for establishing those defences where GxE is concerned. The legal prerequisites I propose are not just applicable to the assessment of GxE as a basis for the aforementioned defences, but also to any form of genetic defence.

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

    Guha, Ambalika (2015)

    Doctoral thesis
    Victoria University of Wellington

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

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  • The effect of maternal nutrition during mid- to late- pregnancy on ewe and lamb behaviour and the association with lamb survival : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, New Zealand

    Grönqvist, Gabriella Veronica (2015)

    Doctoral thesis
    Massey University

    Lambing percentage in New Zealand has increased by almost 30% in the last 20 years. This increase is associated with a greater percentage of twin- and triplet-born lambs which have lower survival rates than singletons. The behaviour of the ewe and her lambs has been associated with lamb survival, however, relevant data on the effect of ewe mid-pregnancy body condition score (BCS) and nutrition on ewe and lamb behaviour under New Zealand pastoral farming conditions is scarce. This research included seven experiments investigating the effects of feeding ewes, with a BCS of 2.0 to 3.0 at mid-pregnancy, either ad libitum or only sufficient to meet pregnancy maintenance requirements from mid- to very late-pregnancy, on ewe and lamb behaviour at 3 to 24 hours after birth. The association between behaviour and lamb survival was also investigated. Observations on ewe and lamb behavioural were conducted at tagging (3 to 18 hours after birth) and in a triangle pen test at approximately 12 or 24 hours after birth. The effects of ewe mid-pregnancy BCS and feeding on behaviour were somewhat inconsistent across experiments, possibly due to variations in the timing and length of feeding treatments. Feeding ewes ad libitum in comparison to pregnancy maintenance requirements did not consistently improve the maternal behaviour score (MBS) of the ewe. This is not surprising as neither of the feeding treatment groups were nutritionally restricting. There was some evidence to suggest that lambs born to ewes offered the pregnancy maintenance diet exhibited a greater need, possibly due to a weaker ewe-lamb bond than lambs born to ewes on the ad lib treatment. This need was characterised in twins, in chapter four, by greater low-pitched bleating rates and decreased time to contact, suck and follow the dam. Similar, but inconsistent results were reported in other chapters. Further, when investigating the relationship between behaviour and survival, it was found that twin-born lambs with the greater need (followed their dam more quickly) were more likely to die. The opposite relationship was found in triplet-born lambs, which may be a reflection of greater competition for milk within triplet-litters compared to twin-litters. Thus, in both twin- and triplet-born lambs following behaviour is an indicator of mortality. The practical use of this behaviour as a tool to predict lamb survival is limited.

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  • A study of Innovative Entrepreneurship in Marlborough, New Zealand : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy (Arts) in Social Anthropology at Massey University, Albany, New Zealand

    Lynn, Amanda (2015)

    Doctoral thesis
    Massey University

    This study responds to the call, made by Anthropologist Alex Stewart, for anthropologists to re-engage with the entrepreneur. The broad aim of this study is to describe and analyse the lived experiences of innovative entrepreneurs in Marlborough, New Zealand. The study is informed by a constructivist-interpretivist paradigm. The research design is based on contemporary interpretative phenomenological analysis conducted within long term participant-observation fieldwork. The study is transdisciplinary in that it is informed by the disciplines of anthropology, economics, psychology and business. Innovative entrepreneurs are an important focus of study due to their role in economic and social change. Thus far anthropological studies have not focused on the innovative entrepreneur in New Zealand. This study makes an original and significant contribution to entrepreneurship studies. I present rich, empirical data on innovative entrepreneurs viewed through the anthropological lens. As such, my study embraces the “humanness” of the participating innovative entrepreneurs. I describe five shared themes that coalesce in a process that guides innovative entrepreneurship. These shared themes are: perfectionistic striving (an adaptive and targeted striving for improvement), pragmatism (openness to new ideas, testing and applying them), development (purposive change within and outside of the self), meaningful reward (validation of value) and being valuable (solving problems to improve outcomes). This process begins with the desire, formed early in life, to be valuable and leads to a life-long process of problem identification and solution construction. This results in self-development as well as developmental outcomes such as businesses and products. I recommend a life span human development approach to future research that includes the collection of deep empirical data and offer a new definition of the innovative entrepreneur. While the innovative entrepreneurs in my study desire to be valuable, the social world in which they are embedded is not always compatible with them. Through analysis of the rich points in the social data I present original social models describing social sets in Marlborough and obstructive processes that usurp institutional power by reinforcing these sets. As entrepreneurs become more visible and influential as leaders they can be drawn into obstructive processes causing some innovative entrepreneurs to avoid—as much as possible—both the local support institutions and the social sets. This has implications which I discuss and I recommend further research to expand upon my findings.

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  • Journey together through the three years: An evaluation of the personal tutor system, a student support model embedded in a Bachelor of Nursing programme in New Zealand : A thesis presented in partial fulfilment for the requirements for the degree of Doctorate in Education at Massey University, Palmerston North, New Zealand

    Hoare, Kathryn Maree (2015)

    Doctoral thesis
    Massey University

    Student support is an important part of tertiary education with different models, systems and approaches used internationally and nationally. The personal tutor system is one such approach to student support embedded within a new Bachelor of Nursing curriculum in a New Zealand tertiary institution. Through the personal tutor system students were assigned a lecturer, an academic member of staff, at the commencement of their study, for the duration of their programme. The purpose of the personal tutor system was to offer students support with their academic development and personal guidance that involved: scheduled and ad hoc meetings; monitoring of progress; personal assistance; and directing some students to seek additional support. Using a mixed methods design, the personal tutor system was evaluated at the time the first student cohort completed the new programme. The study focused on factors that influenced the personal tutor system experience. Third year students and lecturers were invited to participate in two‐phase data collection that involved the completion of a questionnaire (third year students: n=86 and lecturers: n=19) followed by semi‐structured interviews (third year students: n=38 and lecturers: n=10). Most participants confirmed that their personal tutor system experience was positive. Interpersonal interaction between students and lecturers was a key factor, as relationships were central to the personal tutor system. Flexibility was important as the personal tutor system was not a one‐size‐fits‐all approach to student support. At times, competing responsibilities gave rise to undue tension particularly with lecturers’ availability and accessibility for support. Unfamiliarity with the personal tutor system guidelines led to different interpretations for use and consequently confusion with support expectations. However, almost all participants acknowledged the value and potential for the personal tutor system in the BN programme. Recommendations for changes to the personal tutor system included: the creation a proportional co‐ordination role for ongoing management; a review of the guidelines that linked to support resources; time integrated into the BN programme for flexible arrangements with meetings and contact; and a time allocation for lecturers’ workload with resourcing for associated responsibilities.

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  • Analysis of spectral response patterns of Kiwifruit orchards using satellite imagery to predict orchard characteristics of commercial value before harvest : : a thesis presented in fulfilment of the requirements for the degree of PhD Prod Tech in the School of Engineering and Advanced Technology at Massey University, Palmerston North, New Zealand

    Mills, Linda Yvonne (2015)

    Doctoral thesis
    Massey University

    Several characteristics of kiwifruit determine its value to the kiwifruit marketing company, Zespri Ltd, and to the grower. The foremost of these is the dry matter content. Much effort is expended in predicting the final dry matter content of the fruit as early in the season as possible so that the optimal dry matter content can be achieved. Dry matter content is currently measured through a destructive 90-fruit protocol that may be repeated several times in a season on each maturity block. Remote sensing data available from modern satellites can provide four-colour (red, green, blue and near-infrared) data with resolution down to 1-2m, less than the size of one kiwifruit vine. Many indices can be created from these and correlated to the characteristics of plants with indifferent results. This thesis presents the development of an index wherein the four colours are used to create a three-dimensional unit colour vector that is largely independent of light level. This transform was used to allow the direct visualisation of data from a number of satellite images of the Te Puke kiwifruit growing area in New Zealand over five years, for which dry matter content values were available from the 90-fruit protocol. An attenuation model was chosen to correct the top-of-atmosphere light intensities recorded by the satellite cameras to those at ground level. The method of Hall et al., (1991) was found to reduce the variation of fiduciary pixels by the largest amount and was used. The visualisation revealed that there was an axis along which dry matter was ordered by magnitude. A regression line of best fit was applied to this data producing an R2 value of 0.51 with a standard mean-square error of 0.76. This is significantly lower than the average mean-square error of 1.05 for the 90-fruit protocol. Comparison of the predictive power of other indices, based on one image, showed a range of R2 values of 0.008 to 0.49. The method developed in this thesis produced an R2 of 0.70 for the same data.

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  • Exploring informal caregivers' health needs from a capability perspective : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Psychology at Massey University, Manawatū, New Zealand

    Horrell, Barbara Mary (2015)

    Doctoral thesis
    Massey University

    Despite more than forty years of informal caregiving research, the health needs of informal caregivers continue to generate considerable scrutiny. Most commonly, caregiving is portrayed as burdensome and a health risk, although positive and ambivalent experiences have been reported. This study uses the Capability Approach (CA; e.g. Nussbaum, 2000; Sen, 1980) as a theoretical framework to add another perspective to the existing literature regarding informal care provision for older people. Participatory principles informed the research, insofar as the participants were accorded flexibility, control, and helped to co-analyse some of the data. Undertaken in New Zealand, the research comprised two studies. In Study One, 60 caregivers anonymously participated in an online research forum, in an evolving joint discussion of their health needs. Template analysis (King, 2012) of the forum postings, based on Nussbaum’s (2007) capabilities list, highlighted the relational nature of caregiving and the importance of emotions to the caregiving role. Emotional attachment influenced the caregivers’ freedom to choose how they lived their lives, and emotions in general were implicated in the complexities and tensions associated with the caregiving process. An important finding was the self-abnegation of the caregivers who neglected self-care in order to provide care for another. These results led to a second, prospective study that explored in more depth the role of emotions in the everyday lives of caregivers. Six informal caregivers participated in Study Two which involved up to six successive interviews with each participant. Four of the participants kept a solicited diary, which informed the subsequent interviews. Narratives from the second study provided more nuanced data that affirmed the first study’s findings, and contributed to the overall finding that an ethic of care underpins the provision of informal care for older people. The participants valued having the capability to care, evidenced by their emotional attachment, attentiveness and commitment to providing competent care. The participants approach to self-care and their own wellbeing was inseparable from the wellbeing of the person being cared-for. These findings have important implications for social policy aimed at improving the experience of providing informal care for older people.

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  • "Where did I park my car?" : a mixed methods investigation on mild cognitive impairment diagnosis in New Zealand : a thesis submitted in partial fulfilment of the requirements for the degree of a Doctor of Philosophy in Psychology at Massey University, Wellington, New Zealand. EMBARGOED until 11 May 2017

    McKinlay, Alison R (2015)

    Doctoral thesis
    Massey University

    Mild cognitive impairment (MCI) is defined as an objective impairment in cognitive function which spares everyday functional ability. The syndrome is shrouded in controversy regarding definition, cut-off criteria, and clinical utility. Consequently, it is an uncertain label for the client being diagnosed by their healthcare practitioner. To date, minimal research in New Zealand has focused on MCI within specialist assessment services. Reasons for this paucity of literature will be discussed throughout this thesis. The current research aimed to identify how practitioners deliver and perceive cognitive impairment diagnosis, and examine how clients respond to receiving this diagnosis. Client experiences were framed within the common sense model (CSM). This theory originates from health psychology, where coping behaviour is said to be influenced by the cognitive representations that a person has about their condition. Although the framework is previously discussed in relation to chronic illness, international researchers have started to examine the utility of the model in explaining MCI diagnosis response. Given this context, the CSM framework guided the client-focused components of this thesis. In Study One, 57 practitioners who diagnose cognitive impairment completed a questionnaire on labels applied to MCI and beliefs about the value of diagnosis delivery. Responses were analysed using content analysis to gain an impression of professional practice. Cognitive disorder - not otherwise specified (CD-NOS), early dementia, and normal ageing were reported to additionally label the symptoms of MCI in clinical practice. In Study Two, client responses were examined in a small clinical sample (N = 9) diagnosed with MCI and CD-NOS. Participants were interviewed twice within six months of initial diagnosis. Interpretative phenomenological analysis was used to gain insight into how people cope and make sense of their diagnosis over time. Descriptive analyses were also undertaken with a subset of Study Two data to examine changes and differences in coping strategies over time. Findings suggest that participants may not see their diagnosis as an illness or significant health threat in the first six months following diagnosis. This prompts a question on the suitability of an illness model with reference to diagnosis response. Findings from this research add to the literature by highlighting practice associated with an evolving form of clinical diagnosis in NZ.

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  • The association between equine Papillomavirus type 2 and equine Squamous cell carcinomas : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Palmerston North, New Zealand

    Knight, Cameron Greig (2015)

    Doctoral thesis
    Massey University

    Appendix A removed due to copyright restriction.

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  • R² and stock price informativeness : new empirical evidence : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Finance at Massey University, Palmerston North, New Zealand

    Hao, Wei (2015)

    Doctoral thesis
    Massey University

    Abstract taken from Introduction (page 7)

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  • Taxonomies of Taiwanese Aboriginal Musical Instruments

    Cheng, Lancini Jen-hao (2015)

    Doctoral thesis
    University of Otago

    This research aims to discover the indigenous taxonomy systems of Taiwanese aboriginal instruments. This is a cross-cultural investigation providing a panoramic perspective on the musical instruments of Taiwanese aborigines (Austronesians). The term ‘musical instrument’ is used in its broadest sense to refer to all sound-producing instruments in this research. There are many reasons for undertaking this research. For example, until now, few people have known what forms of aboriginal musical instruments have existed throughout the island of Taiwan, and there has been little scholarly discussion about their indigenous names and classifications. The original contribution of the research is its ethnographic fieldwork component, which results in new information concerning indigenous instruments and taxonomic schemes from the opinion of 48 cultural insiders across 17 different aboriginal groups in Taiwan. The researcher’s approach is based on participant observation - by recording the musical activity in either traditional or contemporary contexts, and by interviewing cultural insiders about their traditional music. Also, the researcher analyses the instrumental form, function and meaning of aboriginal instruments across synchronic and diachronic development. The findings in this dissertation provide a new understanding of many unknown musical instruments from different aboriginal groups (e.g. Bunun, Kavalan, Pazih-Kahabu, Puyuma, Rukai, Sakizaya, Siraya and Tsou). This investigation also makes original contributions to extend the instrument type and the numerical entry of the Hornbostel-Sachs system of musical instrument classification. Moreover, this dissertation provides a link between Taiwanese aboriginal instruments and other Austronesian musical instruments. In summary, the many factors that influence indigenous taxonomies of Taiwanese aboriginal instruments include linguistic factors (onomatopoeia, overlapped radicals, and the verbalising affix), how they are played, the materials used in their construction, their performance contexts, as well as players’ gender, social status and religion.

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  • Characterization of Groundwater with Complementary Age Tracers

    Beyer, Monique (2015)

    Doctoral thesis
    Victoria University of Wellington

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

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  • Behaviour of emulsion gels in the human mouth and simulated gastrointestinal tract : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, Manawatu, New Zealand

    Guo, Qing (2015)

    Doctoral thesis
    Massey University

    Food structure greatly impacts the digestion process of food in the human body. Food structure design is a potential strategy to modulate food digestion and develop foods with controlled nutrient digestion and release. This research aimed to understand the dynamic processes of digestion of whey protein emulsion gels from the mouth to the intestine. Therefore, a series of heat-set whey protein emulsion gels, the structure of which was designed by varying NaCl concentration (10, 25, 100 and 200 mM) and oil droplet size (1, 6 and 12 µm), were formed. Mechanical properties in linear viscoelastic region, large deformation and fracture region and microstructure of gels were evaluated. In vivo oral processing and in vitro oral-to-gastrointestinal digestion of whey protein emulsion gels with different structures were investigated with a focus on the effect of gel structure on the gel disintegration and lipid digestion. Results showed that the gel strength increased with increasing NaCl concentration. At the micro-scale, the gel structure became from homogenous to porous with increasing NaCl concentration from 10 to 200 mM. The fragmentation degree of whey protein emulsion gels in the mouth showed a positive linear relationship with the gel strength (i.e. a higher gel strength, the greater gel fragmentation degree). During oral processing, the small oil droplets (~ 0.45 µm) incorporated in the protein matrix were stable without oil droplet release. During gastric digestion, the bolus of the gel containing 10 mM NaCl (soft gel) disintegrated much faster than that of the gel containing 200 mM NaCl (hard gel) in the human gastric simulator (HGS). The disintegration of the soft gel in the HGS was caused by both the abrasion and fragmentation while the abrasion was the predominant mechanism of the disintegration of the hard gel. The larger particle size of the soft gel bolus slowed down the emptying of gels from the HGS. With continued digestion, the emptying of both gels from the HGS was accelerated by gel disintegration. The gel structure greatly influenced the gel disintegration at the micro-scale. The soft gel particles were gradually disrupted into individual oil droplets, with the protein matrix dissolving after gastric digestion for 4 hours while the hard gel particles still retained the oil droplets inside the protein matrix. The colloidal structure of emptied gastric digesta, which generated from original gel structure, still significantly impacted the digestion of whey protein emulsion gels in an in vitro intestinal model. In general, the colloidal structure of the emptied gastric digesta of the hard gel hindered the breakdown of gel particles and hydrolysis of oil droplets more effectively than that of the soft gel. The remaining structure within the hard gel particles limited the free motion of oil droplets, which led to a lower degree of coalescence and breakup of oil droplets. Interestingly, coalescence appeared to occur between neighboring oil droplets inside the emptied gastric digesta of the hard gel during intestinal digestion. The structure of the gels containing 100 mM NaCl became from aggregated particle to emulsion-filled with increasing oil droplet size from 1 to 12 µm. The gel strength also decreased with the increase of droplet size. For the gels containing large oil droplets (6 and 12 µm), oil droplets were released from the protein matrix along with some coalescence during oral processing. During gastric digestion, a higher degree of coalescence of oil droplets occurred and coalesced oil droplets creamed to form a top oil layer. This slowed down the emptying of gels from the HGS. For the gels containing 1 µm oil droplets, most oil droplets still retained in the protein matrix during oral and gastric digestion with minimal instability of oil droplets. In addition, increasing interactions between oil droplets and protein matrix by decreasing oil droplet size hindered the protein hydrolysis. Overall, this research provides an understanding of the way in which food disintegrates in the human body and highlights the role of food structure on the digestion of food in the human body. These findings could assist in designing the functional new foods that deliver health benefits (e.g. lipid regulation, encapsulation and release of nutrients) and improving human health related to food digestion (e.g. dysphagia, dyspepsia).

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  • Estimating the public health risk associated with drinking water in New Zealand : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Masey University

    Phiri, Bernard Joakim (2015)

    Doctoral thesis
    Massey University

    This thesis is concerned with the application of both epidemiological and molecular tools to assess the drinking water safety in New Zealand. Compromised drinking water safety is commonly manifested as gastrointestinal illness. The studies in this thesis were motivated by the desire to nd ways of reducing the burden of such illness in the human population. Although the studies were conducted in the New Zealand setting the methodologies can be readily applied elsewhere. The rst study investigated the factors associated with the presence of microbes in raw water intended for public consumption. Random forest, an established non-parametric statistical method, was used to model data with possible complex interactions and identi ed variables that were predictive of the presence of microbes in raw drinking water. E. coli, which is widely used as a microbial contamination indicator in the water industry, was found to be a better predictor of the presence/absence of Campylobacter (bacteria) than protozoan microbes (Cryptosporidium and Giardia). This suggests that alternative methods of determining the presence/absence of pathogens in water should be developed. In the second study, the relationship between river ow and reports of cases of gastrointestinal illness was described using the distributed lag modelling approach. This revealed a positive relationship that peaked around 10 days after high ow. Further, the river ow-gastrointestinal illness relationship was stronger in small drinking distribution networks than in large ones. The small drinking water distribution networks could be targetted for facility upgrade in order to enhance their ability to deliver microbiologically safer drinking water. The third study utilised culture-dependent methods to assess the public health risk associated with drinking water supplied at outdoor recreation facilities | campgrounds. Water treatment using methods such as ultra violet and chemical treatment were found to be highly bene cial for the campgrounds to deliver drinking water that was microbiologically safe and compliant with water safety regulations. The pro les and functional factors of drinking water microbial communities are described in the fourth study. Techniques from the fast-growing eld of metagenomics were employed for this purpose. The capability of metagenomic techniques to detect multiple pathogens in a single assay was demonstrated. This has the potential to greatly enhance the speci city and sensitivity of microbial water quality testing.

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  • Effects of postharvest treatments on sweetpotato (Ipomoea batatas) storage quality : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University, New Zealand

    Pankomera, Pilirani (2015)

    Doctoral thesis
    Massey University

    After harvest, sweetpotato (Ipomoea batatas) storage root quality is reduced due to weight loss, sprouting and rots. There are also hidden quality losses relating to loss of nutritional compounds. In order to maintain sweetpotato quality during storage, sweetpotatoes need to be stored at 13 - 15 °C and 80 - 90% RH. However, controlled temperature methods are difficult to achieve for subsistence farmers in less developed countries who have limited access to electric power. This work was undertaken to determine the potential postharvest techniques that would extend sweetpotato storage life without compromising phytochemical concentration. Postharvest treatments investigated in this work were hot water dipping (with or without coating) and ethylene (with or without 1-MCP) treatments. The work was undertaken using mainly ‘Owairaka Red’ and ‘Clone 1820’ sweetpotato cultivars. Following treatments, these sweetpotatoes were stored at 25 °C and 80 - 90% RH for 4 to 12 weeks. Hot water dipping (HWD) at 51 °C for 11 min delayed sprout growth by 2 weeks but increased weight loss. Coating (carnauba wax 5%) significantly reduced weight loss, but increased sprout growth in ‘Owairaka Red’. A combination of HWD and coating was effective in reducing both sprout growth and weight loss. ß-carotene content measured in ‘Clone 1820’ ranged from 17.3 to 25.6 mg/100 g dry weight. The concentration was not affected by HWD or coating, but declined by about 30% during 12 weeks storage. The calculated retinol activity equivalent (RAE) ranged from 363 to 537 RAE, per 100 g of edible portion of sweetpotato. Based on the recommended daily intake for vitamin A, a serve of 100 g would supply more than 25% of daily retinol requirement for all age groups, suggesting that even after storage ‘Clone 1820’ is a good source of vitamin A. In addition, no treatment adversely affected the phenolic acid and anthocyanin concentrations. Roots that were HWD showed a subtle increase in total phenolic content, phenolic acids and anthocyanin concentration when compared to control roots, but the effect was shortlived. Previous studies have demonstrated that ethylene is a potential sprout inhibitor, but causes darkening of flesh colour and the development of off-flavours after cooking. Ethylene-induced responses may be inhibited by 1-methylcyclopropene (1-MCP). 1- MCP and ethylene combined effects on sweetpotato physiological, flesh colour and phytochemical variables were assessed during storage. Ethylene treatment with or without 1-MCP inhibited sprout growth, increased root respiration rates by 2-fold, and caused root stem-end split leading to high weight loss and rots. Ethylene treatments also caused flesh darkening, and this was not prevented by a single 1- MCP (1 µL L-1) pre-storage treatment. When roots stored in continuous ethylene were subjected to multiple 1-MCP (1 µL L-1) treatments, the ethylene-induced root splitting and flesh darkening were delayed/reduced whilst maintaining minimal sprout growth. This implies that ethylene-induced negative responses in sweetpotato can be mitigated with on-going 1-MCP treatment. The sensory results showed that roots stored in air were highly preferred by consumers over roots stored in ethylene; nevertheless, acceptance means scores of all treatments were above five, indicating that ethylene-induced flesh darkening was not severe enough to cause consumer rejection. Based on these findings, it is proposed that a combination of HWD and coatings can be used to extend non-refrigerated storage life of sweetpotato with no major effect on phytochemical content. The results on ethylene are consistent with previous findings that ethylene suppresses sprout elongation. However, the associated negative effects outweigh the benefits of using ethylene as a sprout control. Future research therefore should focus on finding ways to get the benefit of ethylene for sprout reduction without incurring risk of root splitting.

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  • Formalist features determining the tempo and mode of evolution in Pseudomonas fluorescens SBW25 : a thesis submitted in partial fulfilment of the requirements for the degree of Ph.D. in Evolutionary Genetics at Massey University, Auckland, New Zealand

    Farr, Andrew David (2015)

    Doctoral thesis
    Massey University

    In order to explain the adaptive process, it is necessary to understand the generation of heritable phenotypic variation. For much of the history of evolutionary biology, the production of phenotypic variation was believed to be unbiased, and adaptation the primary outcome of selection acting on randomly generated variation (mutation). While true, ‘internal’ features of organisms may also play a role by increasing the rate of mutation at specific loci, or rendering certain genes better able to translate mutation into phenotypic variation. This thesis, using a bacterial model system, demonstrates how these internal features – localised mutation rates and genetic architectures – can influence the production of phenotypic variation. Previous work involving the bacterium Pseudomonas fluorescens SBW25 has shown that mutations at three loci, wsp, aws and mws, can cause the adaptive wrinkly spreader (WS) phenotype. For each locus, the causal mutations are primarily in negative regulators of di-guanylate cyclase (DGC) activity, which readily convert mutation into the WS phenotype. Mutations causing WS at other loci were predicted to arise, but to do so with less frequent types of mutation. The data presented in this thesis confirms this prediction. My work began with the identification and characterisation of a single rare WS-causing mutation: an in-frame deletion that generates a translational fusion of genes fadA and fwsR. The fusion couples a DGC (encoded by fwsR) to a membrane-spanning domain (encoded by fadA) causing relocalisation of the DGC to the cell membrane and the WS phenotype. This is one of the few examples of adaptation caused by gene fusion and protein relocation in a realtime evolution experiment. I next took an experimental evolution approach to isolate further rare WS types and characterized these, revealing a range of rarely taken mutational pathways to WS. Lastly, I describe an example of extreme molecular parallelism, in which a cell chaining phenotype is caused – without exception – by a single nucleotide substitution within the gene nlpD, despite multiple mutational pathways to this phenotype. Characterisation of different nlpD mutants suggests this molecular parallelism is caused by a high local mutation rate, possibly related to the initiation of transcription within this gene.

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  • The relationship between self-regulated learning and the use of online portfolios in an online learning environment : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Education at Massey University, Manawatu, New Zealand

    Sasai, Lalida (2015)

    Doctoral thesis
    Massey University

    Self-Regulated Learning (SRL) theory provides an explanation for how learners control and direct their thoughts, feelings, and actions in relation to their learning goals and is considered to be an important requirement for successful learning. Using online portfolios is believed to enhance SRL skills. This longitudinal study conducted over one academic year examined postgraduate students’ SRL skills in relation to their use of online portfolios within an online learning environment, and how they perceived the value of online portfolios. Factors that affected students’ self-efficacy beliefs and perceptions of their ability to be successful in using online portfolios were also studied. A mixed methods research design with an explanatory sequential approach involving three phases was used in the study. In the first phase, at the start of academic year, a questionnaire was used to assess students’ initial SRL skills and their perceptions of the usefulness of online portfolios. Sixty-four students participated in this phase. Two SRL groups comprising students with high and low SRL scores were drawn from this sample. A three-person sub-sample of each SRL group was interviewed in the second phase in order to examine in greater depth the nature of SRL skills for those with high and low SRL scores. For the third phase, a follow-up questionnaire was used towards the end of the academic year to examine whether students’ SRL skills and their perceptions of the usefulness of online portfolios changed over the period of their enrolment in the postgraduate course. For this third phase, 92 students participated. The results revealed that SRL had a strongly positive relationship with students’ perceptions of the usefulness of online portfolios and the relationship between the two variables over time was reciprocal  that is, both constructs influenced each other. The results also showed a significant increase in students’ reported SRL skills and in their positive perceptions of the value of online portfolios over the year. Students attributed the increase in these two variables to using online portfolios to help set their own learning goals, control their own learning, and reflect on their learning. They identified a range of factors, including course support, motivation, peer support, and lecturer support, as helping them to construct and use their online portfolios. However, they identified lack of technology skills and time constraints as the main problems in constructing and using their online portfolios. The findings of the present study indicated that students’ skills across the three aspects (forethought, performance, and self-reflection) of SRL, the three stages of the use of online portfolios (collection, selection, and reflection), and the three elements of learning (personal, behavioural, and environmental) were interrelated. Such findings have important implications for students and university course coordinators to make better use of online portfolios, and for teaching and learning in a university online learning context, particularly in relation to the use of online portfolios as a tool for both storing (product) and reflecting (process) on artefacts of learning. This contribution in turn will help students to better regulate their learning behaviour.

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  • Efficiency of the banking system in Vietnam under financial liberalization : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Banking Studies at Massey University, Manawatu Campus, New Zealand

    Ngo, Dang Thanh (2015)

    Doctoral thesis
    Massey University

    The thesis reviews the (triangular) relationship between financial liberalization, economic growth, and banking development. It points out the causality effect where financial liberalization could improve the efficiency of the banking sector, but on the other hand, it also could lead to instability in the banking system. The recent Global Financial Crisis raised questions as to how and at what level financial liberalization could be done so that for banking development, improvements are achieved but instabilities are avoided. The thesis answers these questions employing a new sample (the Vietnamese banking system), covering a long period (1990-2010), and consistently applying different approaches and models. Three different approaches are used, namely ratio analysis, stochastic frontier analysis (SFA), and data envelopment analysis (DEA). Our findings suggest that the performance of the Vietnamese banking system generally improved during 1990-2002, worsened during 2003-2008, and recovered in 2009-2010. However, there was no statistical association between this performance and the regional or global financial crises in 1997 and 2007/08. Although future studies are needed (since our sample was small and thus, the results may not be accurate), there was evidence that the state-owned commercial banks were less efficient than the joint-stock commercial banks and hence, equitization of the state-owned commercial banks should be speeded up in order to transform their ownership, reducing their size, and improving their performance. There are consistencies between these approaches in terms of defining the efficiency scores, trends, and best and worst performers. Our findings also suggested that the timetrend- DEA, as well as the Fisher Index-DEA models, could be an alternative to the panel- DEA and Malmquist Index-DEA models since they could provide additional information on the performance measures, especially in case of data limitation. However, we could not find consistent results between the ratio analysis model and the ratio-based DEA ones (Panel- and Malmquist Index-DEA) in terms of scores, trends, and determinants.

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  • The good fight : power and the indigenous struggle for the Manawatū river : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Resource and Environmental Planning at Massey University, Manawatū, New Zealand

    Bennett, April Leanne (2015)

    Doctoral thesis
    Massey University

    Power is the central theme of this research. This thesis examines how power structures iwi contributions to freshwater planning and decision-making. Power has received little attention in literature on Māori and natural resource planning, even though it reproduces and potentially transforms existing inequalities among Māori, other actors and planning institutions. In failing to analyse power, scholars have left a significant gap in the literature. In New Zealand, the deleterious effects of agricultural expansion on water have significant implications for iwi, as water is linked to tribal identity and mana. Both past and current generations have struggled to protect water. Contemporary strategies to restore degraded water bodies and reclaim mana, as control and authority, over water include co-management arrangements. Simultaneously, Government has taken an enthusiastic, uncritical stance to promoting collaboration as an approach to freshwater planning, including iwi as one among multiple actors. In this pro-collaboration climate, however, power has been ignored. So, this research asks: How does power structure iwi contributions to freshwater planning and decision-making? To answer this question, a case study was undertaken of the Manawatū River, a highly degraded water body in the lower North Island of New Zealand. Two main methods were used to collect data: semi-structured interviews with 13 key informants and an analysis of 214 documents, including 180 newspaper articles. To interpret the data, the theoretical framework used Pierre Bourdieu’s concepts of field, capital and habitus. The research found that power structures all contributions to freshwater decisionmaking into a hierarchy, with iwi contributions typically marginalised. The hierarchy is a colonial legacy which continues to be reproduced in multiple ways. So, while collaboration, as advocated by the Crown, has some benefits for iwi, it will not help re-structure this hierarchy to enable iwi to regain control over water. Other strategies, such as Treaty of Waitangi settlements, are liable to be more effective. This finding implies that iwi must assess whether co-management or collaboration strategies will enable them to reshape power imbalance. Gaining power is critical to transform inequality, reclaim authority and restore the mauri of water for future generations.

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