28,621 results for Thesis

  • The Impact of Periodontitis on Oral-Health-Related Quality of Life Among Omani Teachers

    Al-Harthi, Latfiya (2012)

    Doctoral thesis
    University of Otago

    Background: Periodontitis is an inflammatory condition affecting the tooth-supporting tissues. It contributes extensively to the global burden of oral diseases. The mild-to-moderate periodontitis is the most common, with prevalence estimates ranging from 13% to 57%, depending on the sample characteristics and the case definition used. Studies in Middle Eastern countries showed that the prevalence of periodontitis tends to be low, around 13%. However, in the Sultanate of Oman, only studies surveying caries in children have been conducted. There are no published studies surveying the oral health status of an adult population. Perceptions of oral health and positive or negative impacts of oral health status on the quality of life cannot really be recorded and must be reported by those who experience the conditions. These perceptions can be characterised by measures of Oral-Health-Related Quality of Life (OHRQoL). Several instruments have been developed to measure OHRQoL. Of these, the most extensively studied and widely used instrument is the Oral Health Impact Profile (OHIP). Only a few observation studies have reported on the impact of periodontitis on OHRQoL. While most of these have shown an association between periodontitis and poor quality of life, many did not allow for the concurrent impact of other oral diseases and conditions on OHRQoL, meaning that the periodontitis-OHRQoL association may have been confounded. Objectives: The objectives of this study are to: (1) describe the oral health status of Omani teachers in the Muscat region, (2) test the validity of the short-form Arabic version of the OHIP in Oman (3) investigate the impact of periodontal diseases on the OHRQoL; and determined whether a biological gradient exists between the disease and OHRQoL. Methods: This is a cross-sectional study of 319 teachers who were randomly sampled from the Muscat region schools’ list of teachers in Oman. The teachers were systematically examined for dental caries, tooth loss, and periodontal attachment loss. OHRQoL was measured using the 14-item Arabic OHIP questionnaire (OHIP-14A). The questionnaire also collected data on each study member’s socio-demographic characteristics, dental care characteristics, self-rated general and oral health, self-rated periodontal status and self-rated wellbeing. Socio-economic status (SES) was determined from each individual’s household income. Results: The age of participants ranged from 23 to 50, with a mean age of 30.9 years (sd = 5.3). There were similar proportions of males and females, and almost half of the participants were in the 20 to 29 years age group. An average of 156 sites were examined per participant. Around 40% of participants had at least one site with gingival recession (GR) of 2+mm, and almost all had at least one site with PD or CAL of 3+mm. More than one-third (36%) of participants had at least one site with 5+mm clinical attachment loss (CAL), and one in ten (12%) had at least one site with 6+mm CAL. For pocket depths (PD), those estimates were 26% and 8%, respectively. A gradient by age group was evident across the different thresholds. Around 6% of sites had some GR; one site in six had 3+mm PD; and one site in five had 3+mm CAL. Only 23% of the participants had had previous periodontal treatment. Only 22 (7.0%) of the participants were caries-free. The number of decayed teeth ranged from 0 to 12. The mean DMFT was 6.3 (sd = 4.2), with two out of three participants having at least one decayed tooth. Females had higher DMFT and FT scores than males, on average, and there was a significant age gradient in mean DMFT, MT and FT. Almost one-third of participants had three or more teeth missing due to caries; this was slightly higher among females. Episodic dental visitors (those visiting only with a problem or pain) had fewer sound teeth and more missing or decayed teeth, and higher DMFT scores overall. In the OHIP-14A questionnaire, the majority of responses were 'never' or 'hardly ever' for most domains. On average, the extent of overall OHIP-14 was 1.2 (sd = 1.4). The mean OHIP score was 14 (sd = 8.0). The highest subscale scores were those pertaining to psychological discomfort. There were no significant differences in the prevalence, extent or severity of impacts of OHIP-14 total score by periodontal status. Moreover, there were no statistically significant associations between periodontal status and self-reported general or oral health. In the multivariate models, no association was observed between periodontal attachment loss and either the prevalence of OHIP-14 impacts or the mean OHIP-14 score. On the other hand, there was a statistically significant association between DMFT and one or more OHIP-14 impacts. Tooth sensitivity, stress level and DMFT were associated with the mean OHIP-14 score. Conclusion: The study showed that dental caries experience was moderate, and the prevalence, extent and severity of periodontitis was higher than estimates reported from industrialised countries such as Australia, New Zealand and the USA. Moreover, the OHIP-14A was shown to have acceptable validity and can be recommended for use in an adult population in Oman. Contrary to most previous studies, there was no association between periodontitis and OHRQoL, irrespective of whether the OHIP-14A or global self-reported general or oral health status was used to represent the latter.

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  • Words with a "Southern Man", Communicating Ecology in Rural New Zealand

    Welvaert, Sofie Adrienne (2012)

    Masters thesis
    University of Otago

    Our understanding of the science that assists us in making everyday decisions varies markedly from issue to issue. We all seem to understand the physics of what happens to our bodies in a car accident. Although we may not know the specific forces involved, most of us know enough about the consequences to make an informed decision when it comes to speed and the use of seatbelts. The science involved in ecological issues tends to be less well understood and the consequences involved in ignoring it, barely acknowledged. Ecological messages tend to be obscured by a mass of complex information, a myriad of technical terms and sometimes there is no clear indication of what we need to know and do. Under these circumstances it is easy for the individual import of the science to be missed in the ecologist’s rush to communicate what is perceived to be important information. While the evaluation of effective science communication is a relatively new field of research, science communication has principles in common with marketing. Effective marketing, just like effective science communication, creates change whether it is persuading you to buy a particular brand of laundry detergent or getting you to wear your seatbelt. Billion dollar industries rely on effective marketing every day and the research behind these campaigns is well established and well-funded. The common objectives underpinning these two areas – marketing and science communication - invites the application of established marketing principles to science communication and this is the intention of the academic component of this thesis. It appears that the key way to ensure a campaign is effective is to identify clear measureable goals and to understand exactly what change is to be achieved. The identification of your target audience and knowledge of the people you are trying to reach is an integral part of effective campaign design. For a campaign to be effective it must be: noticed, remembered and acted on. The creative component of this thesis is the film ‘Green or Gold, it's not black and white’. It was made using some of the key marketing theories identified from the literature. It aims to communicate the issues surrounding land-use in the central South Island of New Zealand. In the academic component of the thesis the film is analysed alongside three other New Zealand campaigns with regard to their approach and effectiveness. This analysis is used to suggest the most appropriate way to approach the communication of ecological issues in rural New Zealand.

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  • The Oxidative Modifications to Cancer Cells Induced by Three Redox-Active Drugs: Auranofin, PEITC and TDSNO

    Deuss, Felix (2012)

    Masters thesis
    University of Otago

    Redox homeostasis is of critical importance for normal cellular functions. The intracellular environment is maintained in a reduced state, upon which, reactive oxygen (ROS) and nitrogen (RNS) species oxidise cellular components and induce functional changes. Proteins are important targets of redox signalling, as their diverse cellular functions may be regulated by the oxidation of specific amino acid residues. The thiol groups of cysteine residues are particularly important due to their roles in activity, intra- and inter-molecular bonding. Abnormalities in the cellular redox state underlie many forms of cancer; these exhibit a shift in the redox balance towards a more oxidative state. Therefore, the pharmacological induction of oxidative modifications to the proteome will selectively induce death in cancer cells. This study aimed to assess the chemical changes induced by three redox-active drugs, auranofin, PEITC and a novel light-sensitive S-nitrosothiol, known as TDSNO, because of their potential thiol modifying activity. A therapeutic range was established for each drug and FTIR spectroscopy was used to identify the chemical effects induced by non-toxic and cytotoxic concentrations. All three compounds induced significant changes to the proteome, however TDSNO and PEITC induced additional minor changes to other cellular components. Non-toxic concentrations of both auranofin and PEITC induced larger chemical changes than cytotoxic concentrations, while a linear correlation to the photo-activated TDSNO concentration was observed. Despite the differences, the changes induced by the three drugs were predominantly co-localised with the nucleus and potentially the endoplasmic reticulum. Furthermore, it was found that the modulation of the glycolytic pathway altered the cytotoxicity of TDSNO. There is therefore potential for these drugs to be used in combination and in the presence of inhibitors of glycolysis, for the selective treatment of cancer.

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  • Algal communities and their response to ocean acidification

    James, Rebecca Kate (2012)

    Masters thesis
    University of Otago

    Ocean acidification is the lowering of oceanic pH that has resulted from the increase of CO2 in the atmosphere. pH is a dominant factor driving the dissociation of inorganic carbon in the ocean and because the pH is lowering, the concentration of the inorganic carbon forms is changing. It is predicted the concentration of oceanic CO2(aq) will increase by around 200%, and the concentration of CO32- will decrease by 56% by the end of this century. CO2 is an energetically cheap carbon source for photosynthesis compared with the other highly abundant inorganic carbon form used for photosynthesis: HCO3-. Increased CO2 availability and lower concentrations of CO32- could influence macroalgal growth and lead to changes in macroalgal community structure. Before we can predict how macroalgae will respond to these changes in their carbon supply, we require a better understanding of the utilisation of inorganic carbon and the extent of carbon limitation in macroalgal communities. Field community surveys and stable isotope measurements showed macroalgal species at wave-exposed sites utilise a higher proportion of CO2 than wave-sheltered species, and there are more CO2-only using species present at wave-exposed sites. The higher CO2 availability caused by thinner diffusion boundary layers at wave- exposed sites compared with wave-sheltered sites is likely to drive these changes in carbon usage. In laboratory experiments, carbon uptake kinetics were examined for two common species of seaweed, Xiphophora gladiata (Labillardière) Montagne ssp. novae-zelandiae Rice and Hymenena palmata (Harvey) Kylin, under water motion (high and low) and pH (8.1 and 7.6) treatments. Results showed that water motion had a greater impact on carbon-uptake than pH. A 6-week laboratory experiment, in which early successional macroalgal communities were grown at two pH treatments (8.1 and 7.6), revealed that these coralline and diatom dominated communities are tolerant to ocean acidification and are able to grow, however, there was reduced growth for calcifying algae at pH 7.6. This project has shown that greater CO2 concentrations could positively influence photosynthesis in some species of fleshy macroalgae by reducing carbon limitation, however, calcifying algae are vulnerable to the oceanic chemistry changes caused by ocean acidification. These varying responses among species and the variability of communities under different levels of water motion is likely to lead to communities responding to ocean acidification at a local scale.

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  • Comparison of socio-economic and life satisfaction outcomes following a stroke or an injury in New Zealand

    McAllister, Susan Margaret (2012)

    Doctoral thesis
    University of Otago

    Background: In New Zealand, people unable to work due to an illness may be eligible for a means-tested government benefit whereas injured people are eligible for a wide range of support including earnings-related compensation through the no-fault Accident Compensation Corporation (ACC). The aim of the study was to compare the effect of this difference on socio-economic and life satisfaction outcomes of individuals who experienced a stroke with those who had an injury, and their main informal carer. Methods: A comparative cohort study was undertaken of individuals aged 18-64 years, who had a first-stroke (n=109). Participants were matched by age, sex, and functional impairment to injured individuals (n=429) participating in the Prospective Outcomes of Injury Study. Demographic, health, socio-economic, and life satisfaction data were collected by interview 3.5 and 12 months after stroke or injury. Logistic regression adjusting for the matching variables, and functional impairment at 12 months, was undertaken. A cross-sectional survey using a postal questionnaire was conducted with carers of individuals with a stroke (n=22) or an injury (n=65) who indicated that their independence was affected at 12 months and their main support person lived in the same household. Logistic regression, adjusting for age, sex, and the impairment level of the individual being cared for, was undertaken. Results: At 12 months after the stroke or injury, the odds of being back at work were 3.1 times greater for the Injury Group compared to the Stroke Group (OR 3.1; 95% CI 1.7-5.6). The Stroke Group exhibited significantly greater decline in their income over 12 months and the mean personal ($29,167) and household ($59,640) income in the Stroke Group was significantly lower than the Injury Group ($48,156 & $87,295 respectively). The decline in income was greater for those in both groups who had a higher income initially, and for those who had not returned to work. The odds of reporting low standard of living (OR=0.64; 95% CI 0.39-1.0), and income insufficiency (OR=0.52; 95% CI 0.34-0.81), were less for the Injury Group. Greater out-of-pocket expenses were reported by the Stroke Group. For both Groups, life satisfaction decreased at 3.5 months and increased again by 12 months, but not to the pre-event level, except for those in the Stroke Group with a ‘Low’ income pre-event whose life satisfaction declined and did not recover. The informal carers of individuals with a stroke showed consistently poorer work, cost, economic, and well-being outcomes compared to Injury Carers, but the small sample size precluded statistically significant differences from being observed. Conclusion: This is the first study to empirically measure outcomes that occur as a consequence of the different financial and social support systems for illness and injury in New Zealand. While it is possible that unknown confounders, or residual confounding, partly explain the difference between groups, the extra financial and rehabilitative support available through ACC are likely to be the main factors influencing these outcomes. This study has implications for government policy to review the financial and rehabilitation support that is provided to people after an illness to protect them against greater decline in their socio-economic status.

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  • Extending the Understanding of the Effects of Cultural Localisation of Websites: The Case of Tourism Destination Sites.

    Tigre Moura, Francisco (2012)

    Doctoral thesis
    University of Otago

    Cultural localisation of websites represents a relevant managerial practice. Studies have indicated that when tailoring web content and website design to fit the needs, characteristics and preferences of target audiences, individuals tend to develop more positive attitude toward the site, have higher purchase intention and greater ease of use, for example. However, the investigation of the effects of cultural localisation of websites has been limited to the context of company websites. The current localisation literature, for examples, does not include websites which clearly triggers hedonic motivation in users. Moreover, it fails to encompass the users’ motivation and involvement and the product types as moderating factors of perception and behavioural intention. Also, the main theoretical rationale employed to justify the effectiveness of the cultural localisation of websites involves only the reduction of cognitive effort applied by users when interacting with culturally congruent sites. This thesis aimed at understanding the effects of cultural localisation of tourism destination websites on users’ perceptions of the destination and its site. Tourism sites were chosen for a series of reasons. First, the leisure tourism context triggers hedonic motivation in individuals. Also, individuals tend to apply their ideal or situational self when conducting evaluations and judgements in the leisure tourism context. Thus, the theoretical proposition stated in this thesis predicted that cultural incongruity between tourism destination websites and users was expected to generate more positive perceptions of the place and its websites in users when compared to culturally congruent sites. In order to test the theoretical proposition and address the aim of the thesis, a two stage research was conducted. The first stage consisted of an exploratory study of 130 destination websites from New Zealand, China and India. The study allowed an investigation of the depiction of cultural values, and the identification of cultural markers, in tourism destination sites. The second stage of the research involved an experiment. An experimental website of a fictitious tourism destination was developed and culturally localised for New Zealanders, based on findings from the exploratory study. Cultural values and cultural markers represented the two independent variables of the main study, and each variable was treated in two levels: congruent and incongruent. 400 New Zealand undergraduate students participated in the study, 100 per condition. As predicted, results indicated that incongruent cultural values and cultural markers led to more positive destination image, higher willingness to travel and more positive perception of the website’s design. No significant effect was found on participants’ online trust, attitude toward the site and perception of navigability. The results are interpreted in light of motivation and self concept theories and the characteristics of the product type. Thus, the theoretical rationale adopted to explain the effects of cultural localisation represents the main theoretical contribution of the thesis. The managerial implications involve the ethical and managerial boundaries to applying cultural incongruity in websites. Finally, it also includes the use of cultural incongruity in social network and travel planning sites and in other contexts where individuals are triggered by hedonic motivation and also apply their ideal or situational self to employ evaluations and judgements.

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  • The role of large, isolated trees in supporting urban biodiversity

    Waite, Edward Mark (2012)

    Doctoral thesis
    University of Otago

    Large, isolated ‘specimen’ trees are a significant part of urban landscapes, yet their role in supporting wider biodiversity remains largely unexamined. The aims of this thesis were to examine how urban, isolated trees contribute to the maintenance of bird and arthropod communities. These aims were met through the compilation and analysis of a dataset on the behaviour of native and exotic birds in forty study trees, representing four genera. A survey was undertaken on the arthropod assemblages on a subset of these trees. Finally, GIS information was incorporated into the bird observation dataset to place the trees within a landscape context. The data presented in chapter two highlighted both bird and tree interspecific differences in how the trees were used by birds. For some bird species, most notably silvereyes (Zosterops lateralis), some of the study trees were used extensively for foraging. For other bird species, native nectivores in particular, the observed behaviour was strongly suggestive of the trees fulfilling a stepping-stone role. In many cases, the movements of birds were correlated with tall vegetation and other large trees, providing further evidence that the isolated study trees were playing a role in the maintenance of landscape connectivity. Significant differences were found between exotic cosmopolitan birds commonly associated with urban areas, such as blackbirds (Turdus merula), and native forest birds. These differences suggest that the stepping-stone role provided by isolated trees may be more important for the native forest birds than the exotic bird species. In chapter three a survey of the arthropod fauna of urban trees was examined. Existing sampling methods had to be adapted to suit the particular challenges associated with sampling urban trees. Significant differences in the arthropod abundance, richness, and diversity were found. These differences were related to both the sampling method used, and the species of tree sampled. This arthropod data was linked to silvereye foraging in chapter four. In contrast to many native bird species, silvereyes thrive in urban areas. This makes them a useful study organism to examine what factors make some species robust to urban development, while others suffer localised extinction. The silvereyes showed an ability to incorporate exotic trees with high arthropod abundances into their foraging patterns, in spite of the general trend for native fauna to be associated with native vegetation. As lack of arthropod prey is a limiting factor for many urban bird species, this may be an important factor enabling silvereyes to thrive in urban areas. In chapter five the bird species richness associated with urban trees was examined, and analysed with regards to spatial data on three scales. At every spatial scale analysed, significant differences were found. The findings suggest that native birds have more narrow requirements regarding which trees they will utilise, and that they are more sensitive to the contexts in which urban trees are situated. These results show that by tailoring urban tree plantings and the contexts in which they are planted, the contribution they make to supporting native birds can be enhanced.

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  • Towards a Chinese vocabulary list for learners of Mandarin as a foreign language at tertiary level in Malaysia : a needs-based study.

    Low, Hiang Loon (2012)

    Doctoral thesis
    University of Otago

    This study aims to find solutions for the problems of ‘how much vocabulary’ and ‘what vocabulary’ when creating curriculum for the learning of Mandarin as a Foreign Language (hereafter MFL). Both the HSK Vocabulary List (1992) and the revised New HSK Vocabulary Lists (2009–2010) were compiled for the purposes of Chinese proficiency tests; however, these lists were not designed to account for the specific local language needs of MFL learners. To overcome the limitations of the HSK Vocabulary Lists, this study has conducted a thorough vocabulary needs analysis, based upon the Hutchinson and Waters’ target situation analysis framework (1992 [1987]) and Nation’s vocabulary needs analysis framework (2001), to identify the vocabulary needs of MFL learners in Malaysia. Four primary areas are studied through the target situation analyses: (1) why, how, when and where Mandarin is used, (2) vocabulary sizes for different proficiency levels, (3) vocabulary learning resources and (4) Mandarin language goals. Questionnaires were used as the primary research instrument to conduct a large scale vocabulary NA. Questionnaires were carefully designed to meet the criteria of construct and content validity, reliability and practicality. Student questionnaires were filled out by 2,534 university MFL learners in Malaysia. Teacher questionnaires were completed by 26 Malaysian MFL instructors and 24 Chinese MFL experts from mainland China, for comparative purposes. The findings reveal that more than 80% of the students aimed to speak basic Mandarin in order to improve their job prospects, to interact with their future clients at the workplace and to communicate with their Mandarin-speaking friends. UiTM learners (medium of instruction: Pinyin) generally required approximately three contact hours compared to the Non-UiTM learners (medium of instruction: Chinese characters) who preferred an average of approximately five hours. However, the UiTM learners requested a higher entry level vocabulary size at 511 words and a higher ultimate vocabulary size at 2,144 words, in contrast to the Non-UiTM students who requested 458 and 1,738 words, respectively. In terms of vocabulary learning resources, learners prioritised daily vocabulary and workplace vocabulary, but not business vocabulary. Working Mandarin or Workplace Mandarin focuses on ‘gathering information for a job’, ‘attending job interviews’, ‘interacting with clients at work’, and so forth, while Business Mandarin emphasises items such as ‘negotiating business agreements’, ‘signing contracts’ and ‘marketing’. A factor analysis for all respondents on 30 possible language goals reduced these goals to six dimensions. Very significant differences of perceptions were identified between students and teachers for ‘job-related language needs’. Students perceived the abilities ‘to get information for a job’, ‘to speak some Mandarin when attending a job interview’, and ‘to interact with Mandarin-speaking clients in future workplaces’ as very important, but teachers did not. One conclusion is that learners’ isolated ‘job-related language needs’ should be emphasised in syllabi so that learners are equipped with basic speaking skills for different work settings. Regarding theoretical implications, this study presents a country-specific vocabulary needs analysis framework for elementary MFL learners at tertiary level. With this framework, all of the procedures can be replicated by other researchers to identify vocabulary needs of MFL learners in other circumstances.

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  • Organic Contaminants in Agricultural and Alpine Streams in New Zealand

    Shahpoury, Pourya (2012)

    Doctoral thesis
    University of Otago

    Organic contaminants have become widespread in the environment due to the high consumption of materials in the modern lifestyle. The contamination of surface aquatic systems can be particularly crucial because pollutants can pose serious risks to the biological communities residing in these ecosystems. Contaminants can also leach though soil and pollute groundwater resources that are often used as drinking water supply in many parts of the world. Good examples of organic contaminants of concern are pesticides and polycyclic aromatic hydrocarbons (PAHs). In aquatic systems, contaminants can be characterized through different sampling techniques, such as sediment and passive sampling approaches. In the present study, sediment samples were used to investigate the effects of farm management practices on concentrations of halogenated pesticides in streams. The sediment samples were collected from 15 streams arranged in five clusters on the South Island of New Zealand. The streams passed through separate farmlands that were managed using organic, integrated, and conventional practices. The samples were extracted using selective-pressurized liquid extraction (S-PLE) and analysed with a gas chromatograph (GC) coupled with a mass selective detector (MS). The results of the study showed that farm management can negatively affect the pesticide concentrations in streams. Conventional farming was generally associated with higher pesticide concentrations. Organic and integrated farming improved the stream quality, although the streams that passed through these farmlands cannot be considered pesticide-free because the residues of pesticides applied in the past can remain in the environment for a long time. The present study also discusses in detail the principles of aquatic passive sampling, highlighting advantages and disadvantages of the technique. Passive sampling, as opposed to spot measurement approach, provides an integrated record of contaminant concentrations in the environment. This is particularly important for aquatic systems where episodic contamination events are expected to occur. The application of passive samplers normally requires a large quantity of organic solvents to be used in both pre-deployment preparation and analysis steps. In order to minimize the amount of solvent used for the analysis, in the present study a novel method was developed for extracting PAHs from silicon rubber samplers using selective-pressurized liquid extraction (S-PLE), together with post-extraction purification with gel permeation chromatography (GPC). The developed method proved to be satisfactory and the mean recoveries for PAHs using S-PLE and GPC were 75 (%RSD = 20) and 97% (%RSD = 16), respectively. The silicon rubber samplers were used in order to monitor concentration pulses of atmospherically transported PAHs in streams during annual snowmelt. The investigated streams were located in Arthur’s Pass National Park on the South Island of New Zealand. Three sampling sites were chosen; two were located along the Otira River and one along Pegleg Creek River. The passive sampling was conducted in nine consecutive periods from July to December 2010. The samplers were extracted and the resulting extracts were purified using the developed method. All samples were later analysed for PAHs using GC/MS. The results of the analysis showed that PAH water concentrations increased in the study area during the snowmelt period. In addition, the study suggested that weather conditions and sampling site characteristics may have affected the observed PAH concentration patterns at different sites during the study period.

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  • Effects of circuit training on muscle strength, cardiovascular fitness, and quality of life in women diagnosed with primary breast cancer

    Fastier, Amy Renee (2012)

    Masters thesis
    University of Otago

    Breast cancer is the most prevalent type of cancer in New Zealand women. As the number of women surviving breast cancer increases, the resultant implications for the health system make research into the physical and psychological effects of breast cancer and its treatment a priority. Due to other competing factors, physical activity is often sidelined during primary care or breast cancer education. Breast cancer literature has reported that exercise reduces many of the debilitating side effects often associated with breast cancer. However, despite the research, breast cancer survivors often experience declines in exercise participation. Furthermore, there appears to be a lack of exercise information available to breast cancer survivors. Significant positive effects of regular exercise on a wide range of outcomes have emerged including, aerobic capacity, muscular strength, body composition, fatigue and quality of life. Although research has focused on either aerobic or resistance training, new research is emerging on the benefits of a combined exercise programme within this population. Circuit resistance training (CRT) offers a potential mechanism through which aerobic and resistance exercise can be effectively combined to target multiple parameters concurrently. Therefore, the aim of this study is to evaluate the effects of a CRT programme over 20 weeks on aerobic capacity, muscular strength, body composition, and quality of life on women diagnosed with primary breast cancer. Twelve survivors of breast cancer, who all completed treatment for an average of 16.2 months, participated in a 20 week study which prescribed two 45 minute circuit sessions per week. Participants were their own controls and comparisons of results from baseline to final measure. Significant improvements in upper body strength as tested through a one-repetition maximum chest press (25.9 ± 3.7 vs. 35.9 ± 5.2kg; p0.05) or body composition measures of weight, skeletal muscle mass, fat mass and body fat percentage (p>0.05). In conclusion, the CRT programme produced significant improvements in muscular strength on the upper and lower body, and various dimensions of quality of life among breast cancer survivors. The results from the CRT demonstrate that circuit training is well tolerated among breast cancer survivors, with no incidence of adverse effects directly attributable to the study.

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  • Relativistic Electron Precipitation: Satellite Observations of EMIC Wave Driven REP

    Carson, Bonar Ray (2012)

    Masters thesis
    University of Otago

    Many recent studies have identified relativistic electrons interacting with electro- magnetic ion cyclotron (EMIC) waves and being precipitated out of the radiation belts into the Earth’s atmosphere. These studies have generally only investigated a few specific geomagnetic storm events, and therefore it is impossible to deter- mine any overall characteristics or trends to do with these events. Therefore, we have undertaken a similar examination of this phenomena, but using a vastly larger dataset; our research utilises all available data from the SEM-2 instrument onboard the NOAA spacecraft collected between 1998 and 2010. A total of 436,422 half orbits from six satellites are inspected by an automatic- detection algorithm, looking for specific characteristics determined to be signatures of EMIC-driven relativistic electron precipitation. 2,331 precipitation events are identified and logged into a database, where other corresponding geomagnetic indices are also included. Statistical analysis of this database identified trends in the data, including in- creased likelihood of event occurrence during geomagnetic disturbances, preference for dusk and night sectors as determined by MLT and the occurrence of the majority of the events outside of the plasmasphere, as determined through use of statistical plasmapause models. Comparison of this database with other studies in the literature provided strong evidence linking our precipitation events with simultaneous observations of EMIC waves. The electron precipitation events are seen to show different characteristics than the proton precipitation events which while occurring simultaneously with our events, more commonly occur without electron precipitation. Our database provides an unique opportunity for comparison with any other study of EMIC waves during the 1998-2010 period. It also provides insights into the relationship of EMIC-driven relativistic electron precipitation with geomagnetic indices, allowing for additional input into any future modeling of electron dynamics in the radiation belts.

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  • Qualitative and quantitative effects of hydrogen peroxide on enamel

    Shah Mansouri, Reza (2012)

    Doctoral thesis
    University of Otago

    Background: A pleasing smile can be considered part of an attractive appearance and having “whiter” teeth is perceived as an integral part of achieving this. Tooth whitening provides a treatment option that is a conservative, relatively quick and inexpensive. It uses bleaching agents such as hydrogen peroxide (HP) at various concentrations that have been marketed for in-office and at home use. Aim: The aim of this study was to investigate the effects of 30% HP and 10% carbamide peroxide (CP) on the nanomechanical properties and the protein content of enamel. Methodology: The effect of bleaching for 30 minutes with 30% HP or eight hours with 10% CP on the mechanical properties of enamel was investigated. This was determined by measuring the hardness (H) and the elastic modulus (E) of twelve sound enamel samples using nanoindentation testing with a Berkovich tip at 25 and 250 mN force, before and after bleaching. The effect of bleaching for 30 minutes with 30% HP on the protein content of sound enamel was also investigated. Protein was extracted from the enamel of twelve sound permanent teeth by precipitation with trichoracetic acid after dissolution of the inorganic phase and the amount of protein was quantified using the Lowry and the Bradford protein assays. Results: The mean value for the E of enamel before and after bleaching with 30% HP was 99.08 GPa ± 3.64 and 98.63 GPa ± 6.44 respectively, and the mean value for H was 4.1 ± 0.4 GPa and 3.9 ± 0.7 GPa before and after bleaching respectively. The nanohardness tests showed no statistically significant difference in the mean values of the E and the H of enamel samples following exposure to the bleaching agent (P > 0.01). From 0.01g of sound enamel, the mean amount of protein detected using the Lowry and the Bradford assays was 5.2 ± 1.2 µg, 2.8 ± 1 µg respectively. After surface treating the enamel with 30% hydrogen peroxide, the mean protein values using the same two protein assays was 2 ± 0.6 µg and 1.1 ± 0.4 µg respectively. These results indicate that bleaching treatment with 30% HP resulted in a significant reduction in detectable protein content (P > 0.01). Conclusions: Bleaching sound enamel with a 30% HP for 30 minutes and 10% CP for 8 hours does not affect the microhardness of enamel despite altering its protein content. Within the limitations of this study, alteration of the protein content in mature, sound enamel by 30% HP bleaching agent did not appear to alter the mechanical properties of enamel.

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  • The Effects of Physical Activity on Postprandial Metabolism: Continuous Exercise or Regular Activity Breaks?

    Peddie, Meredith Catherine Rose (2012)

    Doctoral thesis
    University of Otago

    Sedentary behaviour is a risk factor for cardio-metabolic disease. Results from observational studies indicate that regularly interrupting sedentary behaviour with light bouts of physical activity is associated with a lower risk. It has been proposed (from the results of a series of studies conducted in rats) that sedentary behaviour influences cardio-metabolic risk, principally by acting on processes involved in postprandial metabolism, particularly the activity of lipoprotein lipase. Lipoprotein lipase plays an important role in the clearance of triglycerides from the bloodstream after a meal. In addition the results from two recently performed interventions indicate that sedentary behaviour also influences the action of insulin. Therefore, the aim of the current study was to investigate the effects of prolonged sitting, a single 30 min brisk walk followed by prolonged sitting, and sitting interrupted with regular short (1 min and 40 sec) walks on postprandial lipidaemia, insulinaemia and glycaemia. A randomized crossover, laboratory based study was conducted in Dunedin, New Zealand between February and October 2010. Seventy healthy, normal weight adults (Mean (SD) VO2max 42.9 (10.3) ml·kg·min-1, Body Mass Index 23.6 (4.0) kg·m-2) aged between 18 and 40 y participated in three interventions. The three interventions were: 1) Prolonged Sitting, during which participants sat continuously for 9 h; 2) Physical Activity, in which participants sat for 15 min, walked on the treadmill continuously for 30 min at 60% VO2max and then sat continuously for 8 h and 15 min and; 3) Regular Activity Breaks, in which participants interrupted their sitting every 30 min with a 1 min and 40 sec brisk walk on the treadmill, performing a total of 18 walks over the 9 h period (totalling 30 min of physical activity). In all three interventions a heart rate monitor was worn continuously over the 9 h period, measures of expired air were collected during all walks on the treadmill and resting measurements were collected hourly. Participants were fed a meal replacement beverage at 60, 240 and 420 min. Each meal replacement beverage provided 31.4 ± 6.6 g of fat, 36.8 ± 7.7 g of protein 76.4 ± 16.1 g of CHO and 3105 ± 652 kJ of energy. Blood samples were collected from a venous cannula at baseline and hourly for 9 h, with additional samples collected 30 and 45 min after each feeding. Postprandial measures of heart rate and energy expenditure were calculated as the average of all measurements taken over the 9 h intervention period. Postprandial responses for plasma glucose, insulin and triglyceride were calculated as positive incremental area under the curve (iAUC). Regular Activity breaks increased mean heart rate by 9 bpm (95% CI 7 to 11; p<0.001). There was no difference in triglyceride iAUC between Prolonged Sitting and either Physical Activity or Regular Activity Breaks. However, Physical Activity lowered mean plasma triglyceride iAUC by 0.69 mmol·L-1·h (95% CI 0.20 to 1.19 p=0.006) when compared to Regular Activity Breaks. Interestingly, despite the proposed link between sedentary behaviour and lipoprotein lipase neither Regular Activity Breaks nor Physical Activity were effective at lowering postprandial lipidaemia. In spite of the higher estimated energy expenditure with Physical Activity, breaking prolonged sitting with regular, short brisk walks was more effective than a single bout of continuous physical activity at significantly decreasing postprandial glycaemia and insulinaemia. These findings provide evidence of the profound metabolic benefits of regularly breaking prolonged sitting with short bouts of physical activity. We propose that these findings inform modifications to New Zealand public health guidelines that include the recommendation that all New Zealanders should regularly break periods of prolonged sitting regardless of their other exercise habits, age, or risk of cardio-metabolic disease.

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  • Heterozygosity-fitness correlations and inbreeding in a reintroduced population of Stewart Island robins (Petroica australis rakiura)

    Townsend, Sheena Marie (2012)

    Doctoral thesis
    University of Otago

    Inbreeding occurs when related individuals mate. Inbred individuals are more likely to inherit identical alleles at a given locus, decreasing heterozygosity and increasing the expression of deleterious recessive alleles, resulting in fitness losses or inbreeding depression. Since small, isolated populations will generally become increasingly inbred overtime, inbreeding depression is a potentially important factor influencing the persistence of threatened species. Inbreeding within populations can be detected with pedigrees. Due to the difficulty of obtaining data, however, pedigrees are often unavailable for wild populations. Consanguineous mating and other demographic processes such as genetic drift or population admixture can result in increased non-random associations between diploid genotypes across loci or identity disequilibria (ID). When ID occurs, correlations between heterozygosity at neutral molecular markers (e.g. microsatellites) and traits that reflect fit- ness, or heterozygosity-fitness correlations (HFCs), may arise. Because of the association between inbreeding and ID, HFCs may facilitate the study of inbreeding depression when wild pedigrees are unavailable. The primary aim of this thesis was to determine the effects of pedigree in- breeding (f) on HFCs in a wild, recently bottlenecked population of Stewart Island robins (Petroica australis rakiura). Stewart Island robins are small forest passerines endemic to New Zealand and a subspecies of the South Island robin (P. australis). On Stewart Island, population declines prompted the translocation of 25 individuals in 2000 to an open sanctuary on Ulva Island. This isolated and closely monitored population represents a rare opportunity to study a pedigreed wild avian population with frequent inbreeding. In this thesis I present the development of 35 polymorphic microsatellite markers for use in Stewart Island robins. I also review the suitability of the Ulva Island robin pedigree for studying inbreeding depression and HFCs. The Ulva Island robin population represents a relatively large dataset (957 banded individuals studied over 10 years), with low levels of extra-pair paternity (EPP), a small proportion of unknown individuals, relatively high variance in f and high incidences of close and moderately close inbreeding. In addition, I found no evidence that unequal founder representation within the population has introduced a potentially confounding correlation between parental and offspring f. I examined inbreeding depression using the pedigree, and HFCs in three life-history traits (hatching, fledging and juvenile survival). I report significant HFCs for hatching and fledging success that appear to reflect weak inbreeding depression. I also report, for the first time in an empirical study of a wild population, within-inbreeding class HFCs for juvenile survival that are influenced by pedigree f. More heterozygous same-nest siblings experience increased juvenile survival but only when inbred. My results provide optimism for the continued use of molecular markers in the study of HFCs in evolution and conservation, particularly when populations are small and may accumulate inbreeding. My findings reinforce the need for further research specifically designed to consider factors that influence the detectability and strength of HFCs in wild populations. They also highlight the importance of considering not only pedigree f, but variation in realised inbreeding among individuals that share inbreeding coefficients.

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  • Electing New Zealand's Health Governors: Do elected board members have the appropriate knowledge, skills and experience to govern district health boards?

    Hansby, Oliver Ron (2012)

    Undergraduate thesis
    University of Otago

    The manner by which a health system is governed impacts upon the delivery of health services. New Zealand has a decentralised health system featuring twenty district health boards (DHBs) that are responsible for ensuring the provision of regional health services. Each DHB is governed by a board typically comprised of four appointed board members and seven elected board members. Appointed board members are selected by the government, and must be deemed to have the appropriate knowledge, skills, and experience. On the other hand, elected board members are chosen by the public in triennial DHB elections. Aside from some statutory disqualifiers, there are no prerequisites to standing in these DHB elections. Objectives: This dissertation contributes to the debate on whether elected board members have the appropriate knowledge, skills, and experience to govern DHBs. This dissertation describes the past experiences of elected DHB board members and identifies which of these past experiences are associated with successful candidacy. This dissertation also explores whether elected and appointed DHB board members perceive that they have the appropriate knowledge, skills, and experience to govern DHBs. Methods: The past experiences of elected DHB board members were assessed through an analysis of the candidate profiles submitted prior to DHB elections. Then, the association between these past experiences and the outcome of DHB board candidacy was studied through logistic regression. Finally, all current DHB board members were invited to participate in a short survey focused on DHB governance. Conclusions: According to their candidate profiles, elected DHB board members have a range of past experiences, with the most common being past DHB board membership. Of the past experiences identified, past DHB board membership, past service as an elected representative, and experience as a doctor or a nurse were associated with increased odds of success in at least two of the past three DHB elections. Conversely, past experience in both health and non-health related business and management was associated with decreased odds of success in at least one of the past three DHB elections. Regarding the perceptions of current DHB board members, most elected and appointed DHB board members perceive themselves to have the appropriate knowledge, skills, and experience to govern DHBs. Some appointed DHB board members are, however, sceptical of the competence of their colleagues, particularly those that are elected DHB board members.

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  • Salivary transcriptome biomarkers: For the identification of periodontitis susceptibility.

    Hidayat, Mohd Faizal Hafez (2012)

    Doctoral thesis
    University of Otago

    Periodontitis (gum disease) is a chronic infectious disease affecting the supporting tissue around the teeth. Bacteria cause the infection and subsequently activate the natural inflammatory host response. The response to bacterial infection varies between individuals. Epidemiological studies have shown that only a minority of the population are susceptible to advanced chronic periodontitis while the majority of the population have mild to moderate forms of the disease. Identifying individuals who are susceptible to periodontitis will enable focused patient management and timely preventive programs. A readily available and non-invasive source of potential biomarkers is saliva. The “salivary transcriptome” defines the RNA present in saliva. Significant changes to the salivary transcriptome of oral cancer patients have been described previously. The aim of this study was to discover potential biomarkers of susceptibility with the identification of mRNAs that are differentially expressed in the saliva of healthy and chronic periodontitis patients. Using an Oragene® RNA kit total RNA was purified from the saliva of 10 chronic periodontitis patients and 10 with healthy or only mildly inflamed gingivae (the health/gingivitis group). The quantity and quality of the total RNA was determined, and a measure of gene expression via cDNA was undertaken using the Affymetrix Microarray system. The microarray profiling result was further validated by real-time quantitative PCR. The result showed that there was acceptable quality and quantity of total RNA from saliva but a high proportion of it was of microbial origin and there was insufficient human salivary transcriptome for expression studies. Detecting the human salivary transcriptome is difficult as it is mostly partially fragmented and degraded in saliva. Nevertheless, the prospect of identifying a saliva biomarker in the gene expression profile of susceptible patients is novel however, further work is required to enhance the extraction process of human mRNA from saliva.

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  • Effects of hazelnut consumption on cardiovascular disease risk factors, energy balance, sensory-specific satiety, and acceptance

    Tey, Siew Ling (2012)

    Doctoral thesis
    University of Otago

    Nuts are rich sources of cis-unsaturated fatty acids, vegetable protein, dietary fibre, phytochemicals, and essential vitamins and minerals. Epidemiological studies have consistently demonstrated an inverse association between frequent nut consumption and the risk of cardiovascular disease (CVD). Randomised controlled trials (RCTs) have shown a significant improvement in blood lipid profiles when following a diet enriched in different types of nuts. Interestingly, although nuts are high in fat and energy, several studies report that nut consumption is not associated with adverse weight gain. This raises the question as to whether nuts have unique properties that protect against unwanted weight gain. No studies to date have been designed to determine whether regular nut consumption is different to the frequent ingestion of other energy-dense foods in terms of body weight regulation. Recent evidence suggests that frequent nut consumption may have beneficial effects above and beyond their cholesterol-lowering effect. For instance, nut consumption may also improve novel risk factors for CVD such as oxidative stress, inflammatory markers, and endothelial dysfunction. The current recommended daily serving of nuts (30 g) is largely based on their lipid-lowering properties. The dose of nuts required to influence the aforementioned novel risk factors is unknown. To achieve optimal health benefits, nuts must be consumed regularly and in sufficient quantity. Sensory-specific satiety (SSS) and acceptance (‘desire’ and ‘liking’) have been shown to influence intake both acutely and over the long-term. For example, an increase in SSS may result in early termination of consumption, which may compromise adherence to dietary guidelines. Furthermore, a decline in acceptance over time is likely to reduce compliance to consume nuts on a regular basis. The overall aims of this thesis were: (i) to examine the effects of regular nut consumption on body weight and SSS in comparison to other energy-dense snack foods; (ii) to determine the effects of consuming nuts at different doses on novel risk factors for CVD; and (iii) to assess the effects of long-term nut consumption on acceptance. To achieve these overall aims, two randomised, controlled, parallel studies were conducted. In part one of the first study (Chapter 3), 118 healthy normocholesterolaemic individuals were randomly allocated to receive daily portions of ~1100 kJ/d of hazelnuts (42 g), chocolate (50 g), potato crisps (50 g), or no snack food (control group) for 12 weeks. Body composition, resting metabolic rate (RMR), blood lipid profiles, and diet quality were measured at baseline and at week 12. The results showed no statistically significant differences in changes in body composition, RMR, and blood lipid profiles from baseline to week 12 between the groups, after adjusting for baseline value, sex, baseline age, and baseline body mass index (BMI) (all P ≥ 0.106). However, diet quality improved significantly in the nut group. Compared to all other groups, the percentage of total energy derived from saturated fatty acids (SFA) (all P ≤ 0.045) and carbohydrate (all P ≤ 0.006) was significantly lower whereas vitamin E intake (all P ≤ 0.007), the percentage of energy derived from monounsaturated fatty acids (MUFA) (all P ≤ 0.001) and polyunsaturated fatty acids (PUFA) (all P ≤ 0.011) was significantly higher in the nut group at week 12. In part two of this study (Chapter 4), SSS and ad libitum intake for the snack foods were measured during a tasting session at baseline and at week 12. In addition, ‘desire to consume’ and ‘overall liking’ for the snack foods were also assessed at daily intervals during the 12-week exposure period. Twelve-week consumption of snack foods resulted in a statistically significant reduction in SSS in all three snack groups (P = 0.015). However no such changes were seen in the control group (P = 0.608). Ad libitum energy intake for the snack food increased over the study across all groups including the control group (P = 0.039). Daily exposure to chocolate and potato crisps for 12 weeks caused a significant decline in ‘liking’ (P = 0.002, P = 0.031 respectively). However, nuts were found to be resistant to such an effect, and ‘liking’ for nuts was stable throughout the exposure period. Two important findings of this first study were that regular consumption of 42 g of nuts on a daily basis did not adversely affect body weight, and acceptance of the nuts remained high over 12 weeks. Whether the consumption of higher doses of nuts elicits similar results is unknown. Although 30 g of nuts is recommended to reduce blood lipid and lipoprotein concentrations, the dose of nuts required to influence novel risk factors for CVD may be higher. Therefore, a second study was conducted to investigate whether there was a dose-response effect of nut consumption on markers of inflammation and endothelial function. Importantly, body composition and acceptance were also assessed given the higher dose was in excess of current recommendations. In the second study (Chapter 5), 107 overweight and obese individuals were randomly allocated to one of the three treatment arms: no nuts (control group), 30 g/d of hazelnuts or 60 g/d of hazelnuts for 12 weeks. These individuals were chosen as previous research demonstrates that chronic inflammation and impaired endothelial function is more pronounced among overweight and obese individuals. Body composition, blood lipid profiles, markers of inflammation and endothelial function were assessed at baseline, week 6, and week 12. In addition, ‘desire to consume’ and ‘liking’ for nuts were assessed at weekly intervals during the twelve-week exposure period. The results showed no statistically significant change in body composition from baseline to week 12 in both nut groups. Although 30 g/d and 60 g/d of hazelnuts significantly improved blood lipid profiles and endothelial function compared with baseline, these changes were not statistically significantly different from the control group after adjusting for baseline value, sex, baseline age, and baseline BMI (all P ≥ 0.065). However, hazelnut consumption significantly improved diet quality in a dose-response manner. Compared to the control group, both hazelnut-enriched diets significantly reduced carbohydrate intake (overall P < 0.001) whereas the intakes of MUFA (overall P < 0.001), vitamin E (overall P < 0.001), and potassium (overall P = 0.038) increased significantly. The ‘desire’ and ‘liking’ for nuts remained stable throughout the exposure period in the 30 g/d nut group, whereas both measures declined significantly in the 60 g/d nut group (both P < 0.001). Unlike previous literature, hazelnut consumption had little influence on blood lipid profiles in both studies reported in this thesis. It is important to note that the participants in the first study were normocholesterolaemic while the second study was comprised of overweight and obese individuals. Recent evidence suggests that the response to a cholesterol-lowering diet is less pronounced in weight-stable individuals with high BMI and among those with low baseline cholesterol concentrations. Our study disagrees with previous nut studies, which have shown significant improvements in novel risk factors such as endothelial function. An important difference between the current study and previous research is that our study simply added nuts to participants’ habitual diet. All other studies have not only included nuts, but have also altered the background diet or provided additional dietary advice. An important finding of this thesis is that moderate nut consumption (up to 60 g/d) does not adversely affect body composition. In addition, nut consumption significantly improves diet quality in a way that would be expected to improve CVD risk. On the basis of SSS and acceptance data, the current guideline to consume one serving (30 to 42 g/d) of nuts regularly appears to be an achievable and sustainable behaviour. However, higher intakes (i.e. 60 g/d) compromised participants’ ‘desire’ and ‘liking’ for them. Therefore, this thesis reinforces the recommendation to consume a moderate serving (30 to 42 g/d) of nuts regularly as part of the heart-healthy diet.

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  • Smartphone Diet Application Use & Dietary Assessment in Sports Dietetics

    Jospe, Michelle Rose (2013)

    Masters thesis
    University of Otago

    Background: The availability of diet applications (diet apps) on smartphones is increasing, and this may help sports dietitians employ best practice. Sports dietetic best practices are informed by evidence-based guidelines, which include assessing and prescribing quantitative dietary intake. The use of smartphone apps and implementation of best practices in sports dietetics is currently unknown. Objectives: The aims of the study were to 1) assess the prevalence and perception of smartphone diet app use by sports dietitians; 2) to examine the methods and barriers of dietary assessment and nutrition intervention used by sports dietitians, with focus on best practice; and 3) to compare the prevalence of implementation of best practices by sports dietitians who use diet apps with those who do not use diet apps. Methods: A 27-item cross-sectional online survey was developed and sent to 549 sports dietitians to determine diet app use, as well as dietary assessment and nutrition interven- tion practices in sports dietetics. Respondents included sports dietitians from Australia, Canada, New Zealand, and the United Kingdom, who were surveyed between 22 June and 24 August 2012. Results: The questionnaire had a response rate of 25.1% (138/549). Of the 136 eligible respondents to the questionnaire, 25.0% (n=34) used diet apps with clients in sports dietetics. Diet app users had a positive perception of diet apps. Overall, sports dietitians primarily assessed dietary intake with a diet history (61/125, 48.8%), estimated energy (55/123, 44.7%) and/or macronutrient intakes (59/123, 48.0%), prescribed quantitative nutrient intakes (11/127, 8.7%), and most often referred to Clinical Sports Nutrition (L. M. Burke & Deakin, 2010) (97/118, 82.2%) for sports dietetic guidelines. Only 12.7% (16/126) of sports dietitians used the Nutrition Care Process. The majority of best practices in sports dietetics (5/7, 71.4%) were followed by less than half of the surveyed sports dietitians. More sports dietitians who used diet apps followed best practices compared with sports dietitians who did not use diet apps. Conclusion: This study highlights the gap between best practice and actual practice in sports dietetics. More diet app users followed best practice, suggesting that diet apps can help close this gap. Smartphone diet apps may help implement best practices by enabling sports dietitians to quantitatively assess dietary intake and calculate nutrient intake, thus allowing nutrient goals to be set. As the adoption of smartphones increases and sophistication of the software improves, diet apps will grow in importance and become a valuable tool in the dietetic profession.

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  • Dietary Intake of Choline and Betaine in New Zealand Reproductive Age Women

    Mygind, Vanessa (2013)

    Masters thesis
    University of Otago

    Background: Choline is an essential nutrient, which is required for brain development and methyl group metabolism. Betaine is produced by oxidation of choline, and is also important because of its role in the donation of methyl groups to homocysteine to form methionine. The requirement for choline was set as an Adequate Intake (AI) of ~ 550 mg and 425 mg/day for adult men and women, respectively, with additional choline recommended during pregnancy and lactation. Currently, there is no dietary requirement for betaine. Although choline and choline esters are widely distributed in food, recent data from US NHANES found that only a small portion of Americans were achieving the recommended intake. Betaine can also be found in a variety of food sources, and can be used as a methyl donor, thus sparing some choline requirements. To date, there are no dietary data on choline and betaine intakes in the New Zealand population, and it is therefore unknown whether choline intakes of New Zealanders meet the recommended AI level. Objective: The overall aim of this study was to estimate choline and betaine intakes of a sample of New Zealand reproductive age women, and to compare these intakes with the Nutrient Reference Values for adequacy and excess. Design: Cross-sectional dietary analysis of 140 healthy reproductive age women enrolled in a folate intervention trial. Dietary information was obtained in 2008 using 3-d weighed food records. Average nutrient intake was calculated using nutrient values obtained from the US Department of Agriculture (USDA) database for standard reference and the USDA Database for the Choline Content of Common Foods Release Two. Results: Of the 140 participants enrolled in the study, weighed 3-d food records were analysed for 99 participants. The mean (SD) intake of choline and betaine was 302 (57) mg/d and 156 (64) mg/d, respectively. The total choline intake relative to energy intake and body weight was 0.17 mg/(kcald) and 4.9 mg/(kgd), respectively. Only 12.1% of participants met or exceeded the AI for adult women of 425 mg/d. The top five major food contributors of choline were egg, red meat, milk, bread and chicken; and of betaine were bread, breakfast cereal, pasta, grain and carrot/beetroot/parsnip/swede. Conclusion: Our findings contribute towards the recent emergence of published reports on the range of dietary choline and betaine intakes consumed by free-living populations. In our sample of New Zealand women of child bearing age, few participants were meeting or exceeding the AI level. Nationally representative survey data should be used to determine the choline and betaine content of the diet of New Zealanders across the lifecyle. In the meantime, given recent epidemiological evidence suggesting health benefits of increased choline and betaine intakes, recommendations should be made to encourage the consumption of choline and betaine-rich foods.

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  • An investigation of mtDNA heteroplasmy in New Zealand chinook salmon (Oncorhynchus tshawytscha) and its effects on mitochondrial-based population studies

    Antolik, Caroline (2013)

    Masters thesis
    University of Otago

    Mitochondrial DNA (mtDNA) is commonly used in population and evolutionary genetics due to its unique characteristics, such as maternal inheritance and a lack of recombination. Increasing reports of paternal inheritance and heteroplasmy indicate that inheritance of this molecule may be more complex than originally assumed. As mtDNA is used in a wide range of studies, further work is needed to better understand its characteristics and inheritance. Here, the chinook salmon (Oncorhynchus tshawytscha) was used to investigate mtDNA heteroplasmy and its effect on the mitochondrial genome and population studies. Two heteroplasmic sites had been previously found in the ND1 gene of this population, and the entire genome of five individuals from the New Zealand population was searched for additional heteropaslmic sites. A detailed protocol using a combination of long-range (LR) and standard PCR with Sanger sequencing was developed to search for and confirm heteroplasmic sites in the mitochondrial genome. This process resulted in the discovery of two additional heteroplasmic sites in the COII gene of the New Zealand chinook salmon population. The sequences obtained during the search for heteroplasmy in the chinook salmon mitochondrial genome were used to undertake a more detailed study of selection in the mtDNA coding regions and examine the population structure of the New Zealand population and its source from the Sacramento River in California. Evidence of selection was found in several genes coding for subunits of complexes I, IV, and V (NADH dehydrogenase, cytochrome c oxidase, and ATP synthase, respectively) of the oxidative phosphorylation (OXPHOS) pathway in mitochondria. Analysis of the New Zealand and California populations using the ND1 and COII genes showed evidence of similar structuring in the two populations, with higher genetic diversity in the ND1 region for both New Zealand and California chinook salmon. The heteroplasmic sites seen in the New Zealand population were not found in any individuals from California, supporting other studies of this species that suggest it went through a bottleneck upon transplantation to New Zealand from California.

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