Theses and Dissertations

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    The metabolic health of New Zealand vegans : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand
    (Massey University, 2024) Hill, Lucie
    Background: The popularity of a vegan diet is growing in New Zealand. Though there are potential nutrient deficiencies in a vegan diet, it is generally accepted that a vegan diet has greater metabolic benefits than a Western-style diet. Objectives: This cross-sectional study aimed to explore the metabolic health status and dietary intake of adults who had been consuming a vegan diet for 2+ years. Methods: Data were collected from The Vegan Health Research Programme. Participants completed questionnaires on demographic information, dietary practices and supplement use and a four-day food diary. Participants gave a blood sample for analysis of HbA1c, total cholesterol, LDL-C, HDL-C, Chol/HDL ratio, triglycerides and omega-3 index. Blood pressure, waist and hip circumference measurements were taken and body composition was measured using DXA. Results: Participants (N=212) had a mean (SD) age of 39.5 (12.4) years and were predominantly female (73.1%). Mean (SD) metabolic health markers of HbA1c, total cholesterol, LDL-C, HDL-C, Chol/HDL ratio, triglycerides, diastolic blood pressure and waist circumference were all within normal ranges. Females had a normotensive mean (SD) systolic blood pressure of 114.2 (12.9) mmHg and males were just above the low-risk normotensive category at 124.4 (12.0) mmHg. The mean (SD) omega-3 index result of 3.1 (1.2) placed most participants (86.3%) in the high-risk category for heart disease. Saturated fat intakes for males and females were 8.1% and 9.1% of energy, within the recommended range of 8-10% of energy. Dietary fibre intakes were high, at mean (SD) 55.0 (17.8) g/day for males and 43.4 (12.8) g/day for females. Conclusion: This is the first New Zealand study to examine the metabolic health and dietary intake of adult vegans. The results of metabolic health markers indicate that the vegan diet may confer cardioprotective benefits. The low omega-3 index of most participants is concerning, and warrants longitudinal research to assess the level of risk conferred by a low omega-3 index result in a population with no other metabolic risk factors. Dietary intake data shows the population is consuming saturated fat within the recommended range and high amounts of dietary fibre, which may go some way towards explaining the metabolic health status of the participants.
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    Sister cities, museums, and culturally diverse communities : a pathway to strengthening inclusive community engagement by local government and museums for Asian New Zealanders : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Museum Studies at Massey University, Manawatū, New Zealand
    (Massey University, 2023) Lo, Karyn K.
    Sister cities are long-term, community-driven international partnerships between local governments. They promote opportunities for meaningful community engagement through cultural exchanges, economic activities, and resource sharing. Communities in Aotearoa New Zealand are increasingly becoming culturally diverse and complex, and populations such as Asian migrants and Asian New Zealanders are rapidly growing. The strategic goals of museums, particularly those linked to local governments, include actively connecting and engaging with their culturally diverse communities. This thesis examines two case studies with established sister city relationships and community focused museums linked with local governments. Sister city activities between Porirua City and Lower Hutt City in New Zealand and counterparts Nishio City and Minoh City in Japan have brought unique opportunities for citizens of these cities. Cultural institutions Pātaka Art + Museum and The Dowse Art Museum have legacies of public programming and exhibitions for the community. By analysing archival documentation, interviews with key participants, and maintaining a critical socio cultural approach through forms of narrative inquiry, this research aims to better understand the potential of sister cities for the community and the heritage sector. In this context, a counter narrative reveals the growth and increasing relevance of responding to the cultural diversity in New Zealand communities including Asian New Zealanders. Within the two case studies, evidence shows that sister cities are existing community-based resources that encourage unique community activities to flourish. Part of the early sister city movement in New Zealand in the 1990s, they were pathways for local governments and museums to utilise for meaningful community engagement through cultural, educational, and economic activities. These were strengthened by collaboration between committed leaders in local government, cultural institutions, and community organisations. Furthermore, people-to-people connections and trust-building were essential for cultural and economic community outcomes to flow. This thesis argues that these outcomes are shared objectives that strengthen community engagement, and sister cities could be effectively utilised by local governments and affiliated community-focused museums to support culturally diverse communities. Currently, however, New Zealand museums and local governments do not fully utilise the potential of sister cities despite their commitment to these communities.
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    Determining the relative validity of a Food Frequency Questionnaire (FFQ) for assessing nutrient intakes against Four-Day Food Diaries (4DFDs) of New Zealand adults following a vegan diet : the thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand
    (Massey University, 2023) Hassall, Catherine
    Background: In recent years, veganism has gained traction in developed countries. A vegan diet eliminates animal products and animal by-products including milk, yoghurt, cheese, eggs, honey and gelatine. It is often adopted for animal welfare, environmental concern and associated health benefits. As the vegan diet becomes increasingly more common, a validated food frequency questionnaire (FFQ) is needed for future research regarding the health benefits and risks of the vegan diet. To our knowledge the only validated FFQ for the vegan adult population was developed in the USA. This FFQ is unsuitable for use in New Zealand (NZ) due to cultural, ethnic and food supply differences. Aim: This study assesses the relative validity of a semi-quantitative FFQ for assessing nutrients against a four-day diet recall in vegan adults living in Auckland, New Zealand. Methods: As a part of The Vegan Health Research Programme, a convenience sample of adults aged >18 years whom had adopted a vegan diet for a minimum of two years, were recruited for a cross-sectional observational study. Participants (n=167) completed both a four-day food diary (4DFD) and FFQ, which were compared for the relative validity of 31 nutrients. Relative validity was assessed using correlation coefficients, paired t-tests or Wilcoxon signed rank test, cross classification and weighted kappa statistic, linear regression and Bland-Altman plots. All 31 nutrients underwent energy adjustment. Results: Correlation coefficients improved after energy adjustment with values ranging from 0.116 – 0.661. Out of the 31 nutrients, 25 showed improvement in correlation after energy adjustment. Following this, 12 energy-adjusted nutrients were correctly classified (i.e. >50% correctly classified). After energy adjustment, weighted kappa analysis moderately improved the outcomes with values ranging from lowest value 0.149 (caffeine) to highest value 1.10 (vitamin B6 and vitamin E). Of the 31 nutrients assessed, 24 had higher mean intakes in the 4DFD compared to the FFQ. In Bland-Altman and linear regression, the slope of bias was statistically significant (p-value 0.05). For energy adjusted nutrients (n=17), saturated fat (SFA), poly-unsaturated fat (PUFAS), sugars, riboflavin, phosphorus, and iron were non-significant, indicating that the measurement differences between FFQ and 4DFD were not significantly dependent on mean nutrient intakes. Conclusion: Despite nutrients iodine, vitamin B6, total folate, niacin equivalents and niacin showing poor correlations, the FFQ was reasonably accurate at measuring relative validity of the remaining 26 nutrients. However, it is noteworthy the FFQ tended to underreported on most nutrients compared to the 4DFD. This FFQ could be used in future research to assess the relative intake of nutrients of adult vegans living in NZ. However, it should not be used to assess absolute nutrient intakes.
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    Bone density and dietary calcium in New Zealand vegans : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Nutrition and Dietetics at Massey University, Albany, New Zealand
    (Massey University, 2024) Clark, Abril
    The restrictive aspect of a vegan dietary pattern warrants attention, as it may lead to individuals unknowingly obtaining low intakes of calcium. Moreover, several international studies have reported low calcium intakes in vegans. Furthermore, prolonged low calcium intakes can result in reduced bone mineral density (BMD) and increased risk of developing osteoporosis later in life. In older adults, a calcium deficiency will exacerbate bone loss as ageing is associated with a decline in BMD. Moreover, pregnant women are at increased risk of developing a calcium deficiency due to the increased demands of calcium that is required for the growth of foetal bone. The evidence of a vegan diet impacting BMD have been inconclusive in the literature, therefore further research is required to understand bone health of vegans. Especially, in the context of NZ vegan adults as the measurement of bone parameters and calcium intakes have not been investigated in this population. Objectives: To describe calcium intake and bone health of NZ adults following a vegan diet. Methods: This cross-sectional study included adults (N=212) (>18yrs), who followed a vegan diet for more than 2 years. Demographic and lifestyle information was obtained from questionnaires. A 4-day food record was completed for analysis of calcium, zinc, protein, magnesium, phosphorus and vitamin C intake and compared to the Estimated Average Requirement (EAR). Weight, height and BMI were obtained, BMD was measured at the hip and spine using dual x-ray absorptiometry (DXA) and reported as Z-scores. Participants were categorised based on BMD Z scores stratified as follows: low BMD (for age and sex) <-2.0 and normal BMD >-2.0. Blood samples were taken for PTH, 25(OH)D and plasma calcium concentrations were corrected for albumin. All values are presented as mean and standard deviation. Differences in bone parameters between BMD groups were analysed using multiple T-tests. A linear regression analysis examined the association between calcium intake, corrected calcium concentrations, serum PTH levels, BMI, and physical activity levels and BMD Z scores at the lumbar spine and femoral neck. Results: Overall, Z scores at the lumbar spine and femoral neck were -0.29 ± 1.12 and -0.24 ± 0.89), respectively. Corrected calcium concentrations were 2.21 ± 0.33 mmol/L. Overall, calcium intake was 917 ± 347.23 (range 195 to 2,429 mg/day). The main source of calcium in the vegan diet was tofu and plant-based milks. The intake of protein (77 ± 27.80) g/day, magnesium (569 ± 181.05) mg/day, and vitamin C (145 ± 96.94) mg/day met the EAR, excluding vitamin and mineral supplements. However, the intake of phosphorus (1,472 ± 459.98) mg/day and zinc (10.6 ± 4.01) mg/day were below the EAR. Only BMI significantly predicted BMD Z-scores at the lumber spine (P = 0.004) and femoral neck (P = 0.003). Conclusion: The study found that most vegans had normal BMD for their age and sex, adequate calcium intakes and bone homeostasis markers. Despite mean intake of calcium exceeding the EAR, very low intakes demonstrated significant variations between participants. Tofu was identified as the main plant-based source of calcium amongst participants. Moreover, longitudinal research is required to understand the long-term impact of a vegan diet on bone health.
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    Tāngata whaiora / service user perspectives on the effectiveness of a DBT residential treatment programme : a thesis presented in partial fulfilment of the requirements for the degree of Master of Arts in Psychology at Massey University, Aotearoa New Zealand
    (Massey University, 2023) Furness, Emma Kathryn
    The perspectives of tāngata whaiora / service users who have been treated with Dialectical Behaviour Therapy (DBT) in a residential programme in Aotearoa New Zealand were explored to determine which interventions and programme elements were effective and ineffective. People who are typically referred to a DBT residential programme are managing severe and chronic mental distress, use mental health services frequently with complex and multiple mental health diagnoses. This was a qualitative study with the aims of giving tāngata whaiora / service users a voice and provide opportunities for clinicians to enhance their service delivery. The foundations of the study were based on community and clinical psychological epistemologies, and predominantly social constructionist theory. Data was gathered via in-depth interviews with five participants who had been through the programme and analysed using reflexive thematic analysis (TA). Analysis of the data resulted in three main themes and two subthemes that centred around three domains. These domains were related to clinical DBT interventions, environmental and other factors that are not typically assessed when looking at treatment effectiveness, and relationship quality. The results supported much of the international and local literature that explores service user perspectives. The findings from this study appeared to show that DBT was useful to clients particularly learning and practicing DBT skills. Non-clinical interventions and environmental factors also made a difference, such as time in nature and doing recreational activities as a group. Healthy relationships, including those with peers, support networks, and professionals were vital contributors to any resulting wellbeing, and reciprocity and kindness in professional relating increased trust and aided in turning points. Offsite support to consolidate skill use in the community and establish new identities was valued, and a greater focus on physical health and other non-clinical supports such as secure housing is recommend.
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    Effect of incorporation of a heat tolerance gene into dairy cattle and effect on farm profitability : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Animal Science at Massey University, Manawatū, New Zealand. EMBARGOED until 18th December 2024.
    (Massey University, 2023) Thant, Aung Myo
    Heat stress is an impediment to dairy production not only in tropical countries but also in temperate countries. In previous studies, dairy cows with a slick hair phenotype were more resistant to heat stress than cows with wild-type hair. Therefore, the incorporation of the slick hair gene, a heat tolerance gene, into dairy cows would be an opportunity to improve heat stress resistance of dairy cows, and it may also enhance productivity and profitability of dairy cows in temperate countries. The objectives of the current study were to evaluate the effect of incorporation of the slick gene into dairy cattle and the effect on farm profitability in New Zealand. Performances between the first cohort born in 2017, comprised of slick (SL) cows (n = 6) and the contemporary (CT) cows (n = 144) were compared across four production years (2019/20 to 2022/23), whilst a second cohort born in 2019, comprised of SL cows (n = 20) and the CT cows (n = 105) were compared across two production years (2021/22 and 2022/23). For the 2017-born group, milk volume, fat, and protein yields of SL cows were 9%, 13%, and 9% lower than those of CT cows. Liveweight (LW), body condition score (BCS), somatic cell score (SCS), and survival rate of SL cows were 6%, 11%, 18%, and 31% greater, respectively, than those of CT cows. Moreover, the age at first calving (AFC) of SL cows was 25 ± 8 days greater than that of CT cows, but calving interval (CI) and inseminations per pregnancy were not different between SL and CT cows. Slick cows required more calving assistance, however, the level of veterinary assistance for calving was lower than CT cows in the 2017-born group. Income from milk over feed cost (IOFC) for SL cows was 17% lower than that for CT cows. In the 2019-born group, milk volume, fat, and protein yields of SL cows were 33%, 29%, and 24% lower, respectively, than those of CT cows. The survival rate of SL cows was 19% lower than that of CT cows, whilst LW, BCS, and SCS of SL cows were 4%, 8%, and 6% greater than those for CT cows. The AFC for SL cows was 11 ± 4 days greater than that for CT cows, but the CI and inseminations per pregnancy were not different. Slick cows required more calving assistance both at a slight and veterinary assistance level, while CT cows required more significant level calving assistance in the 2019-born group. The IOFC for SL cows was 43% lower than that for CT cows in the 2019-born group.
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    Does exploratory behaviour predict predatory behaviour in the Aussie bronze jumping spider (Helpis minitabunda)? : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Albany, New Zealand
    (Massey University, 2023) Caffell, Melissa
    Individual variation in behaviour, also known as animal personality, has been described in diverse taxa for hundreds of years. However, it is only recently that information about the influence of personality traits on populations and ecosystem dynamics has started to emerge. Predator-prey interactions are important drivers of evolutionary processes, shaping communities and altering trophic cascades. Most studies to date that have investigated the links between personality and predation have focussed on the effects of personality traits of prey on predator-prey interactions. It is becoming increasingly evident that the personality traits of predators and the interactions between predator and prey personalities also influence predatory interactions. Personality assays are usually performed in the laboratory where researchers have greater control over environmental variables than in field assays. However, the controlled environment of the laboratory may change animal behaviour leading to results that are not ecologically relevant. In my thesis, I first investigated whether individual performance in emergence and exploration assays is correlated between laboratory and field environments in the Aussie bronze hopper (Helpis minitabunda; Araneae, Salicidae) (Chapter Two). Then, using what I learned in Chapter Two about the design of exploration assays, I investigated whether exploration behaviour in H. minitabunda is correlated with predatory behaviour (Chapter Three). While I found no correlation in emergence behaviour between my laboratory-based and field-based assays, there was a strong correlation in exploration behaviour. I also found no correlations between exploration behaviour and predatory behaviour. This suggests that laboratory-based exploration assays, but not emergence assays, are likely to generate ecologically relevant results in the jumping spider H. minitabunda. However, exploration behaviour may not be a good predictor of predatory behaviour in jumping spiders. Further testing with more complex arenas and different types of prey may be more likely to show a relationship between exploration and predation behaviour. The results of my research support the use of laboratory assays to test personality traits but also highlight the importance of comparative tests to check that laboratory assays reflect behaviour in more natural environments. My results will hopefully encourage further research investigating personality traits and their influence on predator-prey interactions.
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    “After getting the courage to go…” : an interpretative phenomenological analysis of the customer experience of people who stop going to therapy : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Psychology at Massey University, Auckland, New Zealand
    (Massey University, 2023) Broadhurst, Sara
    Objectives: The study investigated the customer experience of people who had chosen to stop going to therapy, after one to three sessions of 50-60 minutes. In addition, it sought to understand if this experience influenced their future likelihood of using therapy and what they would recommend to others about therapy. Design: Qualitative interview study. Methods: Six people participated in semi-structured interviews, of between 60 and 90 minutes, about their customer experience of therapy with a psychologist or counsellor in Aotearoa New Zealand, who stopped after one to three sessions. The qualitative experiential methodology of interpretive phenomenological analysis was applied to the interview transcripts. Results: Using the four customer experience stages as a framework, the analysis generated themes and subthemes which provided insight into the customer experience and dropout decisions. First, in the pre-experience stage negative connotations still exist about mental health, although these have improved over time. Second, in the pre-purchase stage, participants were anticipating the therapy experience, with subthemes of process and expectations. Third, in the purchase stage, the details matter. Included are four subthemes: the physical space, customer feelings, therapist in-session behaviours and the termination experience. Finally, in the post-purchase stage, participants remained optimistic about therapy, with the subtheme that participants would recommend therapy to others, but with caveats. The participants’ decision to engage in future therapy or to recommend therapy to others was not influenced by having an unsatisfactory experience. Conclusions: The results of research to date on the causes of client dropout from therapy is broadly inconclusive and there is little research from a qualitative or customer experience perspective. Considering each stage of the customer experience brings a different perspective to the variables that influence dropout. In addition, it provides valuable insight into the customer’s decision to terminate, the things that need to be true for people to participate in future therapy and what they say to others when recommending therapy. This study makes a number of contributions for therapists looking to reduce the dropout rate of people attending their service.
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    Phenotypic characterisation of members of the Lachnospiraceae family isolated from ruminants : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Microbiology at Massey University, Manawatū, New Zealand
    (Massey University, 2023) Rajasekaran, Krsana
    Microbial fermentation in the rumen employs the metabolic capacity of microorganisms to degrade lignocellulose from the diets consumed by ruminant animals. Advances in genomic, metagenomic and culture independent methods for studying microbiomes have caused a lag in the functional characterisation of isolated cultures. Moreover, understanding the interactions between microbes during rumen fermentation may help in producing strategies to improve animal productivity and address environmental impact issues such as enteric methane emissions. In this study it is demonstrated how cultured strains are required to accurately describe the functional traits of rumen bacteria. Members of the Lachnospiraceae family are one of the most abundant bacterial groups in the rumen, however, many of its isolated members are yet to be fully characterised or properly classified. In this study, the genomes of 45 Lachnospiraceae strains sequenced in the Hungate 1000 project were functionally annotated using the web-based annotation tool, Protologger. These predictions were then compared with phenotypic traits from the corresponding strains, uncovered using microscopy, carbon utilisation testing, and by analyses of short-chain fatty acid production, and headspace hydrogen. The results indicate how the genome can assist in the culturing and studying of rumen microorganisms but should not be solely relied on for the elucidation of functional traits. Phenotypic characterisations of the 45 Lachnospiraceae strains revealed a preference for the resultant soluble components of cellulose degradation rather than hemicellulose. Starch and pectin were more readily fermented in comparison to cellulose and xylan. End product analysis revealed that the studied strains produce acetate, butyrate and propionate, products known to contribute to host health and nutrition. Ethanol, formate, lactate and less commonly succinate were produced as fermentation products demonstrating the potential of the strains to participate in interspecies metabolite transfers. A subset of the strains including members of the genera Lachnospira, Eubacterium and Oribacterium as well as unclassified Lachnospiraceae bacterium strains were shown to produce methanol from pectin degradation. End products of fibrolytic fermentation by the 45 Lachnospiraceae strains can potentially act as substrates for methanogenic archaea. The results of this study help to improve the knowledge surrounding the poorly studied Lachnospiraceae family and increases the overall utility of the Hungate 1000 culture collection. Additionally, the comparison between genotypic predictions and the phenotyping, accentuates the importance of culture-based studies, providing an incentive to continue cultivating representative strains from the rumen environment to clarify how various microorganisms are contributing to rumen fermentation.
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    Development of a focused ultrasonic array system for pasture biomass estimation : a thesis presented in fulfilment of the requirements for the degree of Master of Engineering at Massey University, Albany, New Zealand
    (Massey University, 2023) Jiang, Zhilin
    The ability to accurately measure pasture biomass can significantly impact the profitability of the pasture agriculture industry. One technique that has been used to estimate pasture biomass is to measure pasture height using ultrasonic transducers. It was traditionally achieved using a single ultrasonic transducer with a wide beam angle. Additionally, the previous studies using this method only used the first arrival time of the echo from the top of the grass. However, this can lead to overestimating grass height due to isolated pieces of grass, which may not be directly below the sensor. It does not measure the pasture density. Also, height measurement errors may occur when the sensor is mounted on an agricultural vehicle as the vehicle bounces and tilts. To solve these problems, Legg and Bradley developed a new ultrasonic air-coupled transducer array to estimate the biomass of pastures and achieved good experimental results. However, it was believable that measurement accuracy can be further improved using near field focusing of the transmit and receive arrays. This work describes the development of an ultrasonic array system capable of focusing on the near and far fields for pasture biomass estimation. It extended on the system developed by Legg and Bradley. Angular measurements were made with the array attached to a computer controlled turntable system for different near- and far-field beamforming configurations. It was found that improved beamwidth and dynamic range were obtained when the system focused on the receiver in the near field. Some initial lab measurements were also performed on pasture samples, comparing the effect of using the array's transmit far-field and near-field focusing. The results indicate that focusing the array in the near field improves the performance in detecting the grass, particularly the top, compared with focusing the receiver in the near field and the transmitter in the far field. However, more work is needed, including field trials.