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  • Evaluation of utilisation of the Prevention of Mother-to-Child Transmission of HIV Programme in Central province, Kenya

    Ngugi, Catherine Njeri (2013)

    Masters thesis
    The University of Auckland Library

    Background: The PMTCT HIV programme has been one of the most successful HIV preventive interventions towards HIV-free future generations. However, even though the programme is virtually effective in developed countries, many developing countries are reporting child HIV infections due to the MTCT. The programme has existed in Kenya for more than a decade, yet in 2011, 12,894children were HIV infected due to MTCT Objective: To evaluate the PMTCT programme, especially the HIV testing from the antenatal period to the postnatal period among expectant parents attending Nyeri Provincial General Hospital in Central Province, Kenya. Design: Retrospective analysis of the hospital registers. Methods: Three hospital registers were analysed for the period from July 2009 to September 2012. The registers were for antenatal, intrapartum and postnatal care respectively. Each register documented the utilisation of PMTCT services by the expectant parents. Descriptive and inferential statistics were produced to analyse data from the registers. Results: The PMTCT services utilisation was sub-optimal. Of the 504 expectant mothers who attended the antenatal clinic, 59.9% came once, 80.4% had their first visit in the third trimester (between weeks 28 and 40) and only 6.9% were accompanied by their partners. All the women were HIV tested in their first visit but only 12.1% were rescreened after three months, and only 3.8% had been tested prior to the current pregnancy (p=0.000). No expectant mother was tested for HIV intrapartum or postpartum. The children of the 504 mothers who were HIV tested were those whose parent/s were known to be HIV positive or who had presented to a child welfare clinic with recurring symptoms suggestive of a failing immune system. Conclusion: Public health programs need to strengthen the PMTCT and HIV prevention programmes to ensure that HIV testing preconception and in pregnancy is fully implemented and strengthened, alongside continued education of the public through community programmes and the media. To avert further horizontal and vertical transmission of HIV, there is a need to address urgently the identified missed opportunities in the PMTCT program. These programmatic challenges require health system redesign and strengthening, resource allocation, addressing research gaps and reassessing the current PMTCT policies.

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  • Data fitness for use in research on alien and invasive species

    McGeoch, M; Groom, QJ; Pagad, Shyama; Petrosyan, V; Wilson, J; Ruiz, G (2016)

    Report
    The University of Auckland Library

    The discovery, access and appropriate use of primary biodiversity data are critical for alien and invasive species (A&IS) research at continental, regional, country and subnational scales. Sustainable, reliable, timely, and accessible data on A&IS is essential to the long-term management of this key threat to biodiversity, including the ability of countries to meet the Honolulu Challenge and to achieve Aichi Target 9 of the CBD Strategic Plan for Biodiversity 2011-2020. GBIF provides a range of essential information services for A&IS researchers, including but not limited to taxonomic and occurrence information. After broad consultation with the research and A&IS community, a suite of recommendations were identified under five broad topic areas: 1) Strategic approaches, 2) Improving existing data, 3) Expanding information content, 4) Functionality, and 5) Communication and engagement. Several recommendations are relevant for other data users, but the availability, quality and timeliness of these data are especially critical for A&IS because of the real-world consequences resulting from the negative impacts of biological invasions. Alien species occurrence includes taxonomically verified species presence records or absence information at a locality with a geographic coordinate, or in a prescribed area, such as a management or geopolitical unit or site (Latombe et al. 2016). Alien species occurrence information is the single most important variable necessary to support research, monitoring and management of A&IS.

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  • Multisensor data fusion strategies for advanced driver assistance systems

    Rezaei, Mahdi; Sabzevari, R (2009)

    Book item
    The University of Auckland Library

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  • Repository as a Service Bibliography

    Zhao, Yanan (2013)

    Scholarly text
    The University of Auckland Library

    The Repository as a Service Bibliography includes selected English-language journal articles, conference papers and technical reports that are useful in understanding the concept of repository as a service in academic and research institutions.

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  • A Brushless DC Motor Drive Without a DC Link Capacitor

    Hewa Kokawalage, Samitha Ransara (2015)

    Doctoral thesis
    The University of Auckland Library

    In recent years, economic and environmental considerations have led the industry towards energy efficient technologies. As a result, in the context of industrial motor drives, Brushless DC (BLDC) and Permanent Magnet Synchronous (PMS) motors have become popular as energy efficient and reliable alternatives for induction motors. Both BLDC and permanent magnet synchronous motors are electronically commutated based on the position of the rotor by using voltage source inverters that consist of a rectifier, a DC link capacitor and an inverter. In comparison to the other electronic components in the circuit, the DC link capacitor has a limited lifetime, which is severely dependent on the ambient operating temperature. However, with advancements in technology, direct power converters such as matrix converters that do not employ DC link capacitors are becoming popular in industry. At present, matrix converters and similar style direct converters are economically feasible in high power applications and are expected to be economically feasible for low power ratings in the future. A technique to eliminate the DC link capacitor from conventional BLDC motor drives is proposed in this thesis. Without the DC link capacitor, the BLDC motor directly operates from the rectified mains supply. A single switch control technique that allows speed and torque control of the BLDC motor is adopted. The proposed technique is simulated and experimentally validated. Also, a comprehensive performance comparison is carried out between the proposed technique and the conventional techniques. Although the proposed technique produces periodic torque ripples, the effectiveness of the proposed technique is validated for low cost BLDC motor drives. A new comprehensive buck converter based mathematical model for the BLDC motor drive is presented to analyse the torque ripple. Using the model, uncontrollable torque regions that occur due to the variable input voltage of the DC link capacitor free BLDC motor drive are identified. The reduction in torque due to the absence of the DC link capacitor is obtained by iteratively solving the mathematical model. The proposed buck converter based model is verified by comparing the analytical results, simulated results, and the experimental results. To compensate for the torque ripple, a compensation technique based on an actively controlled small DC link capacitor is proposed. A further simplified buck converter based model for the DC link capacitor free BLDC motor drive is proposed for practical purposes. The simplified model is compared with the comprehensive buck converter based model to show the accuracy of the model. Although the proposed compensation technique increases the hardware complexity of the motor drive, the overall cost is expected to be lower. A price comparison between the conventional BLDC motor drive and a DC link capacitor free BLDC motor drive with the proposed compensation technique is presented using volumetric pricings obtained through retailers. The effectiveness of the proposed compensation technique is verified by simulations and experimental results. As a solution for complex controls associated with matrix converters, a simple switching algorithm that facilitates the driving of a BLDC motor by a 1 3 matrix converter is presented. Safe commutation techniques are described in detail and the proposed technique is verified by using simulation and experimental results. In principle, the techniques proposed in this thesis are expected to be useful in manufacturing low cost BLDC motor drives with comparable performance.

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  • Quantification of climate change impacts on catchment water balance

    Pham, Hoa (2015)

    Doctoral thesis
    The University of Auckland Library

    Water balance modelling at the catchment scale is valuable for regional planning, design and management of water resources systems as well as for risk assessment and disaster management. This is due to the fact that water-related disasters such as floods and droughts have become more frequent and destructive as a result of climate change which has been observed worldwide over past decades. As part of climate change, changes in precipitation and evapotranspiration are likely to have dramatic impacts on catchment water resources. This results in altering the catchment streamflow and runoff volume. Literature indicates that in practice current water balance models consider the effect of precipitation change rather than evapotranspiration, which is usually assumed to be time-invariant. On the one hand, precipitation estimation in a changing climate is considerably driven by extreme events, particularly by their magnitude and occurrence. The frequency analysis of extreme occurrence based on partial duration series (PDS) may outperform that based on annual maximum series (AMS), however this has not yet been examined with future data. On the other hand, the impacts of climate change on evapotranspiration at the catchment scale have not yet been finalized in terms of methods and data sources used to estimate evapotranspiration. This research thesis develops guidelines on future precipitation projections based on extreme events using frequency analysis of partial duration series. This is tested for cases of point precipitation at individual stations and areal precipitation over the North Island of New Zealand. The testing period ranges between 1945 and 2010. Statistically downscaled daily precipitation from CGCM3.1/T47 and GCM HadCM3 models with spatial resolution of 3.750 x 3.750 and 2.50 x 2.50 respectively, were compared to that directly obtained from RCM HadCM3 at 0.050 x 0.050 spatial resolution for the 1961-2090 period. Moreover, the variation of evapotranspiration across the Waikato catchment and its three forest and grass sub-catchments is accordingly examined for the first time using the integration of the FAO- 56 method coupled with very high spatial resolution RCM HadCM3 data. As a result, the combined effects of changing precipitation and evapotranspiration on the future runoff and volume of the three selected sub-catchment are projected. The results of this research indicate that, in general, precipitation and evapotranspiration have been changing from present to the predicted future and this change has a dramatic impact on catchment runoff. Thus the prediction is that daily precipitation will increase by 1.17% and 2.095% for the 2011-40 and 2041-70 periods, respectively, and the predicted annual precipitation will increase by about 0.89% until the end of 21st century. Likewise, the increase in daily and annual evapotranspiration is about 0.4% to 1.2% per 30-years. Water losses due to evapotranspiration are higher from grassed surface than that from forested surface. As a consequence, mean annual runoff is projected to decrease by 27.8% or to increase by 7.3% per 30-years from 2001 to 2090 depending on the sub-catchment, at the highest rate. In addition to above findings, this research also provides a guideline on the projection of future precipitation based on extreme events using frequency analysis of partial duration series. This could be useful for studying the variability of precipitation with details on how to cope with its complexity. This PhD research attempts to develop a deeper understanding of hydrological response subject to changing climate, as well as adding some case studies of a quantitative nature unlike most of the previous studies.

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  • Image-assisted dietary assessment Evaluating the potential of wearable cameras to enhance self - report in the 24-hour dietary recall method

    Gemming, Luke (2015)

    Doctoral thesis
    The University of Auckland Library

    Background Traditional methods of dietary assessment are prone to self-report bias. Images captured by wearable cameras may reduce self-report bias for foods and dietary energy intake (EI). Aims To investigate the use of wearable cameras to (1) reduce the reporting bias associated with traditional self-reported dietary assessment, and (2) passively record and assess contexts of dietary behaviours. Methods Five modules of research were undertaken: (1) a secondary analysis of the 2008/09 New Zealand Adult Nutrition Survey (ANS 08/9) estimated the prevalence of low energy reporters (LERs), (2) a systematic review examined evidence for image-assisted methods of dietary assessment, (3) a feasibility study explored the use of wearable cameras to enhance self-report in the 24-hour dietary recall, (4) a doubly labelled water (DLW) study validated a wearable camera imageassisted 24-hour dietary recall, and (5) secondary analysis of images collected during the validation study explored the utility of wearable cameras to objectively record, and reliably assess, environmental and social contexts of eating episodes in free-living settings. Results The primary findings were: (1) 21% of New Zealand men and 25% of women were classified as LERs in the ANS08/9, and a systematic bias was observed with LERs more prevalent amongst women, people aged >65 years, and Maori and Pacific peoples, (2) literature published up to 2013 suggests images can provide objective information to independently verify and assess selfreported dietary intake but the limited existing evidence highlighted the need for further research, (3) a small study (n=10) using wearable cameras revealed unreported or misreported errors in the 24-hour dietary recall, which increased self-reported dietary EI, (4) a DLW study (n=40) showed that wearable cameras reduce reporting bias for dietary EI in 24-hour dietary recalls by 9% in men (from 17% to 9%) and 6% in women (from 13% to 7%), and (5) wearable cameras images can be analysed to objectively and reliably assess important contexts of dietary behaviours such as eating location, physical position, social interaction, and media screens. Conclusion Wearable cameras significantly reduce the reporting bias for dietary EI in the 24-hour dietary recall. Used in nutrition research, wearable cameras provide a new tool to verify and enhance self-reported dietary intake, and compared to self-report alone, allow additional information on dietary behaviours to be objectively assessed.

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  • A Three Dimensional Wireless Power Transfer System

    Raval, Pratik (2014)

    Doctoral thesis
    The University of Auckland Library

    Wireless power transfer (WPT) systems are becoming ubiquitous in industry. Out of the forms of WPT, inductively coupled power transfer (ICPT) is of interest to this thesis because of the inherent advantages and widespread use. In current ICPT systems the power area provides restricted one- and two-dimensional load displacements. Alternatively, there is a lack of a volumetric power zone for supporting three dimensional load displacements. This thesis aims to extend the aspect ratios of ICPT systems to support a cubic power transfer volume to provide freedom of three dimensional load displacements. This is done by mathematical analysis involving magneto-quasistatic equations, finite-elementmethod (FEM) software and experimental verification. Initially, the analysis begins with PowerbyProxis 3D Proxi-Point to identify limitations and improvements. This research proposes an AA-battery cell charging ICPT system. Firstly, a singlephase system is proposed. The averaged magnetic-flux-density (MFD) throughout the cubic power zone is 34.5μT producing a predominant vertical field component between 86%-98% producing flux-leakage. Secondly, a multi-phase system is proposed with motivation of reducing flux-leakage. This is done by producing a rotating field. The averaged MFD in the cubic zone is 22.7μT. The tangential component of magnetic flux in the box accounts for up to 76%-91% of total magnetic flux. The proposed systems lead to an inevitable problem of comparing single- and multi-phase ICPT systems. So, a FEM software methodology is proposed based on transient-response to compare root-mean-square waveforms. This shows the single-phase system is 5.8% more efficient at distributing MFD throughout the cubic power transfer volume compared to the multi-phase system. Next, a unique secondary magnetic structure is proposed capable of inducing power along three-orthogonal axes with a customized ferromagnetic core and three pick-up coils. The FEM simulations show the core providing low-reluctance pathway to the induced flux. Next, the single- and multi-phase push-pull resonant circuitry using external controller CompactRIO was customized, simulated and implemented on printed-circuitboard. Finally, the magnetics were implemented using ferrite-cores and Litz wire. The resulting single- and multi-phase systems were shown to charge a AA-battery cell in 6 hours 31 minutes and 7 hours and 16 minutes compared to 3D Proxi-Points 12 hours.

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  • Epigenetics in the Regulation of Xenobiotic Responses

    Zhang, Jinbi (2014)

    Doctoral thesis
    The University of Auckland Library

    Xenobiotics are naturally occurring or anthropomorphically derived chemicals which are not generally expected to be present within the body. Through the course of evolution, organisms have developed elaborate ways to cope with xenobiotic exposures. However, the underlying molecular basis by which the protective mechanisms are triggered, and specifically targeted, is not yet fully defined. In particular, the importance of epigenetics (widely considered the mediator of environmental challenges to cells) in the regulation of xenobiotic detoxification responses have received little attention to date. The current work embodies both a „lead-target‟ and genome-wide discovery based assessment of transcriptomic and epigenomic changes induced by mycotoxin challenge in biologically relevant models systems. Managed exposure trials in the ruminant sheep are used to replicate natural exposure in an in vivo context, while human cell line studies allow specifically for empirical testing and validation of functionally relevant pathways inferred from the field testing. Notably, the current work represents the first time that a comprehensive alignment of phenotype, gene expression and multiple forms of epigenetic signature (including miRNA and traditional and novel DNA methylation) has been carried out in a ruminant, a significant technological advance given the relative paucity of genomic information currently available ruminant animal models. The extension of this knowledge into an established human cell culture system, has further underpinned the exploration of additional implied regulatory mechanisms, notably those involving of miRNAs. Seminal observations arising from these studies illustrate: (1) the pivotal involvement of the PI3Kinase and Wnt signalling pathways in the initial response to mycotoxin exposure, (2) the importance of miRNA in further propagation and persistence of this signalling through a hitherto under-appreciated mechanism involving the „suppression of the suppressors‟ of Wnt signalling, (3) the far broader spectrum and complexity of the expected and novel DNA methylation changes (including hydroxymethylation) across target genes influenced by mycotoxin exposure, and (4) the apparent selectivity of terminal gene effector activity in response to specific mycotoxin triggers, notably the CYP2C family of detoxification genes in this instance. Collectively, these data indicate that the degree of „susceptibility‟ to mycotoxin challenge can be defined by the endogenous activity of, and/or inducibility, of terminal detoxification pathways. Further, this susceptibility is embodied in an apparently cryptic epigenetic signature which is only expressed upon challenge, and which determines the stratification of pathological consequence following exposure.

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  • Understanding Reciprocity in Chinese Social Media: Examining the Influence of Social Capital and Emotion on Reciprocal Behaviour

    Zhu, Andrew Qiang (2015)

    Doctoral thesis
    The University of Auckland Library

    The functioning of social networking sites (SNSs) depends on reciprocal behaviours. This research begins from the premise that in SNSs reciprocity is a key element facilitating the establishment and development of interpersonal relationships between strangers. Specifically, the proposed Social Capital – Emotion – Reciprocity conceptual model and hypotheses concerning the effects of social capital and emotion on reciprocity were derived from the literature and from exploratory research. The conceptual model particularly utilised the Cognition – Emotion school of thought, which conceptualises the act of reciprocity as an outcome of an iterative process of cognitive evaluation of social capital and emotion. The cognitive evaluation of social capital was tested in two experiments. In the experiments, the concepts of bridging social capital and bonding social capital were operationalised and manipulated, and consistent effects were found. In both experiments, discrepancies in relative levels of combined capital, bridging capital and bonding capital affected the likelihood of reciprocity (i.e., more social capital generates more reciprocation). Specifically, discrepancies in bridging capital strongly affected reciprocal behaviour. Discrepancies in bonding capital are significant, but less important. There was no interaction effect between bridging social capital and (indirect) bonding social capital, however an interaction effect did exist when bridging social capital and (direct) bonding social capital were tested. Findings from hypothesis tests provided strong evidence to support the conceptual model, with emotion acting as a mediator between social capital and reciprocal action. Specifically, bridging social capital had a larger impact on reciprocity through the mediation of emotion, and in practical terms, this finding is consistent with the significance of the concept of “who you know” in Chinese business practice. Overall, reciprocity in Chinese social media can be considered as a process of mutual recognition between user-benefactors and user-recipients, each of these actors cognitively evaluates the embedded value of the other’s social capital, which is mediated through emotions triggered in social networking practice. The research findings contribute to the theoretical understanding of reciprocity and practice relevance in virtual environments. The mixed methods design focused on the practical relevance to the research context and provided consistent findings through a sequential development of experiments and modelling, which enhanced the validity of the research outcome. Finally, limitations and directions for future research are described with respect to the broader conceptualisation of reciprocity and the specific operationalisation of potential constructs.

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  • Interactions of the cannabinoid CB1 and dopamine D2 receptors

    Hunter, Morag (2015)

    Doctoral thesis
    The University of Auckland Library

    The effects of cannabinoids in the nervous system are predominantly mediated by cannabinoid receptor 1 (CB1), a G protein-coupled receptor (GPCR). GPCRs are known to form homodimeric and heterodimeric structures, which affect the signalling and regulation of each constituent receptor. CB1 has been shown to have functional interactions with the dopamine D2 receptor (D2). This thesis explores the structure, regulation and function of the CB1-D2 heterodimer. A bioluminescence resonance energy transfer (BRET) assay was utilised to detect constitutive CB1-D2 heterodimer, which was not detectibly altered by receptor agonists. BRET was also utilised to test a proposed heterodimer interface containing four key residues on transmembrane helix 1 of each receptor, however mutation of these residues did not significantly disrupt detection of heterodimer. Previous studies on GPCR heterodimers have suggested that interactions may occur throughout the protein synthesis and ligand-mediated trafficking pathways. Immunocytochemistry-based receptor trafficking and expression assays were used to determine whether CB1 and D2 interact in their regulation. Subtle differences were found in CB1 agonist-driven internalisation in the presence of a D2 agonist. Co-expression of CB1 and a flag-tagged D2 resulted in changes to flag-D2 processing, perhaps by the addition of a post-translational modification, although it is not clear if this is solely a modification of the flag-tag. When activated concurrently, CB1 and D2 have been shown to “switch” signalling phenotype from Gαi-like to Gαs-like activity, resulting in accumulation of cAMP. When this signalling interaction was first observed by Glass et al. (1997), it was hypothesised that this may be a result of the receptors competing for a limited pool of Gαi proteins. If this were the case, this mechanism would also be in effect when CB1 was expressed alone. In order to test this, a mixed population of cells was created and sorted by flow cytometry on the basis of CB1 surface expression. cAMP assays performed on these cells showed that cells with low to moderate expression of CB1 inhibit cAMP production, while cells with high CB1 expression increase cAMP accumulation. In conclusion, while it is likely that CB1 and D2 form a constitutive heterodimer, this does not affect ligand-mediated receptor trafficking. CB1 expression does, however, change the synthesis and processing of flag-tagged D2 in a manner that has yet to be determined. Since CB1 expression alone is sufficient to change the predominant cAMP phenotype to Gαs, presumably by competition of G proteins, this work suggests that CB1-D2 heterodimerisation may function simply to increase the local competition for G proteins, rather than the dimer itself mediating the functional signalling switch.

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  • Neuropsychological, Psychological and Functional Outcomes 12-Months Post-Subarachnoid Haemorrhage: Population-Based Sample Compared to Matched Controls

    Nicholson, Rebecca (2015)

    Doctoral thesis
    The University of Auckland Library

    Stroke is a common neurological disorder that is a leading cause of disability worldwide and may result in deterioration of functioning in neuropsychological, psychological and functional abilities. While accounting for a small proportion of all strokes, subarachnoid haemorrhage (SAH) affects a comparatively young age group who live with its burden for longer. A thorough understanding of SAH survivors’ short-term (≤12-months) outcomes and trajectory is imperative as most change and rehabilitation occurs during this time. However, previous research has been limited by use of hospital- and clinic-based samples, comparison to normative data, limited outcomes focus, and use of brief measures. The current population-based study examined SAH survivors’ (n=30) outcomes throughout the first 12-months compared to control participants (n=29) matched on age, gender and ethnicity. Both groups were assessed using a neuropsychological test battery (e.g., verbal and visual memory, cognitive flexibility, processing speed, cognitive screening measure) and on psychological (anxiety, depression, overall) and functional (stroke symptoms, disability, health related quality of life [HRQoL]) outcomes; the SAH group at 28-days, 6- and 12-months post-SAH. As compared to controls, the SAH group performed significantly worse with greater proportions falling in the impaired range on some neuropsychological outcomes (e.g., cognitive screening measure) and most psychological and HRQoL outcomes throughout the 12-months, despite good outcomes regarding stroke symptoms and disability. Some early improvement in outcomes was found but this plateaued during the 6- to 12-month period and SAH survivors’ outcomes remained poor compared to controls. Psychological and HRQoL outcomes in particular were interrelated, with previous stroke and surgical clipping related to worse HRQoL outcomes. The current findings demonstrate the importance of psychological and HRQoL outcomes in particular throughout the first 12-months post-SAH as compared to the more frequent emphasis of stroke symptoms and disability, suggesting a different direction for assessment and intervention focus. Neuropsychological outcomes are also impaired, though more research using a larger population-based sample and test battery are required to better understand domain specific impairment, trajectory and relation to other outcomes.

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  • Nutrient utilization, acquisition and distribution during embryonic, larval development and metamorphosis of the sea cucumber Australostichopus mollis (Holothuroidea: Aspidochirotida)

    Peters Didier, Josefina (2015)

    Doctoral thesis
    The University of Auckland Library

    The egg nutrient composition and utilization during embryonic and larval development of the holothuroid Australostichopus mollis are examined in the context of maternal investment of the Echinoderms. At the same time, this study assesses the influence of different microalgal diets on the nature and quantity of nutrients accumulated by the feeding auricularia larvae, leading to the identification of important nutrients for the successful completion of metamorphosis and juvenile formation. Nutrient composition of the egg, mainly represented by structural compounds (proteins and phospholipids), reflected well that of echinoderms with planktotrophic development, although A. mollis egg nutritional content was slightly lower than that of other echinoderms with similar egg size. Triacylglycerol (TAG) was the main energetic lipid provided by the mother in the egg to fuel the formation of the feeding larvae. More studies on the facultative feeding period (FFP) of A. mollis are required to establish if A. mollis have lower metabolic rates than other echinoderms, as appears to be the case of planktotrophic ophiuroids. After the onset of larval first feeding, the microalgal diet did not affect the type of lipids accumulated as a nutrient reserve. The microalgal diet did, however, affect the ability of the larvae to build energetic reserves. Dunaliella tertiolecta was found to be an unsuitable diet for A. mollis, while Chaetoceros muelleri led to increased larval lipid accumulation. In preparation for the perimetamorphic period, A. mollis accumulated free fatty acids (FFA) and the same maternally-derived energetic lipid, TAG. Feeding A. mollis auricularia larvae showed that the hyaline spheres (HS), unique holothuroid larval structures, played an important nutritional role during the A. mollis perimetamorphic period. HS were a good indicator of larval nutritional condition, and served as the main storage location for TAG accumulated from the diet. Lipids appeared to be transported from the digestive epithelium to the area of formation of the HS in a novel way, which involved the mobilization of lipids through the gel-filled blastocoel in specialized lipid transporting cells (LTC). TAG in the HS supported the formation of the fully functional juvenile. The information presented in this thesis, which shows the first nutritional data on eggs, larvae and juveniles of a planktotrophic holothurian, is not only valuable for studies of life-history theory, maternal investment and the field of larval biology, but has significant implications for sea cucumber aquaculture.

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  • Investigation of the effects of preheating on the characteristics of micro combustion

    Turkeli Ramadan, Zerrin (2015)

    Doctoral thesis
    The University of Auckland Library

    The requirement for efficient power sources for portable electronics and miniature mechanical devices, such as laptops, micro robots or micro aerial vehicles, has led to research on ultra micro gas turbine (UMGT). The ultra micro gas turbine is one of the most promising power sources for small scale applications due to its higher power and energy densities compared to currently used batteries. In order to realise UMGT as a viable power source, its individual components have to be developed, since downscaling introduces new problems for each component. Since the micro combustor is one of the key components of UMGT, it is an obvious area for investigation and improvement. Until now, it has been very difficult for micro combustors to achieve wide flame stability, high combustion efficiency and clean combustion with low pressure loss, due to the associated downscaling problems, such as high heat loss ratio and small residence time. In order to overcome the issues associated with smaller residence time, preheating the reactants was investigated in the present study, both experimentally and numerically. Two different domains were used in the two different methods. The effects of preheating the reactants on the flame stability and combustion characteristics were investigated experimentally on a 46 mm inner diameter quartz-walled flat flame combustor. The preheating was provided with external heaters. The flame shape and behaviour were observed with different air mass flow rates and equivalence ratios. The experimental results showed that preheating widened the flame stability limit. From the experimental results a new correlation was developed between mass flow rate, reactant temperature, air to fuel ratio and the diameter of the micro combustor. With this correlation, it is possible to determine the minimum combustor diameter required for stable flat flame combustion. Also, in order to have a stable flat flame at higher mass flow rates, the correlation enables the calculation of the required reactants temperature, and is a major contribution to the design of micro combustors. Furthermore, it was found that with the flat flame combustor, very clean, that is, almost complete combustion was achieved with both natural gas and methane as fuels. In addition, different flame holder materials were investigated for their pressure loss characteristics and usability for UMGT applications. On the other hand, the effects of preheating on the flame stability and species concentrations were investigated numerically within a 2 mm diameter micro combustor tube, over two-dimensions. The simulations were performed with both adiabatic walls and nonadiabatic walls. At high incoming flow velocities, preheating was shown to widen the flame stability limit. On the other hand, there is no advantage in preheating for low incoming flow velocities or low mass flow rates. A comparison of employing different skeletal and detailed reaction mechanisms was made. Furthermore, in the non-adiabatic case the effect of heat loss through the outer wall via convection and radiation were investigated with different heat transfer coefficients. In conclusion, preheating widens the flame stability limit and provides flame sustainability even at very small scales. The information generated in this research will help the development of UMGT as a viable alternative to conventional power sources at small scale.

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  • The response of eIF2α kinases to plant virus infection

    Immanuel, Tracey (2015)

    Doctoral thesis
    The University of Auckland Library

    When the eukaryotic translation initiation factor 2 α (eIF2α) is phosphorylated in several eukaryotes, general mRNA translation is inhibited, but some mRNA species that contain an upstream open reading frame (uORF) are preferentially translated. In plants, two types of eIF2α kinases have been reported - general control non-derepressible-2 kinase (GCN2) and protein kinase RNA-activated (PKR). The aim of this research was to further elucidate the role of eIF2α phosphorylation in plants, with a particular focus on the response of eIF2α kinases, including a putative PKR, to virus infection. It is not clear whether in plants, as in other eukaryotes, if phosphorylation of eIF2 regulates translation of mRNAs with particular uORFs. To determine whether this type of regulation occurs in plants, a Luciferase/Renilla reporter system and yeast general control non-derepressible-4 (GCN4) uORFs were used. The uORFs did not regulate the translation of a main reporter ORF in Nicotiana benthamiana plants, regardless of the eIF2α phosphorylation status. In mammals, viral double-stranded RNA activates PKR. There is some evidence to suggest that plants also encode a virus-activated eIF2α kinase; however, this kinase has not been identified. Arabidopsis thaliana (At) calcium-dependent protein kinase-19 (CPK19) has been identified as a putative PKR-like kinase. This research demonstrated that although AtCPK19 phosphorylates eIF2, the phosphorylation event does not occur on the critical serine residue of eIF2, making it unlikely to be a plant PKR. Arabidopsis lines overexpressing AtGCN2 did not have viral resistance, nor was eIF2α phosphorylated in response to virus infection. In lines transformed to ectopically express human PKR, PKR could not be detected and had a similar phenotype. However, N. benthamiana plants that were treated with glyphosate to induce eIF2α phosphorylation did become infected less rapidly compared to plants that were left untreated. Finally, by undertaking research to repeat, connect and extend published work that indicated 58- kDa inhibitor of protein kinase (P58IPK) is an inhibitor of virus-activated plant eIF2α kinase activity; this research determined that the published results were not repeatable in a very similar pathosystem. Instead, there was no virus-activated eIF2α kinase activity in plants, with or without P58IPK. Overall, the conclusion from this thesis is that the only eIF2α kinase encoded by plants is GCN2 and that under the conditions tested, eIF2α is not phosphorylated in response to virus infection.

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  • Casualness: it's not about what it looks like it's about what it does

    Newby, Kate (2015)

    Doctoral thesis
    The University of Auckland Library

    My research consists of site-specific projects that form relationships with locations through actions. e projects draw directly from the situations in which they are presented. I examine concepts such as being in the world, addressing the everyday, the role of the travelling artist, the artwork as object, and casualness, and feed off a combination of sources and methodologies. I may draw on disciplines such as interior design and architecture, but I apply them as only an artist would. ough very specific, I intend my art works to come across as open and casual gestures. rough my work I explore whether context and situation can be just as informative and useful as materiality or supposed content of the work itself. Underpinning my process is a performative ethos. I investigate the way material interventions made in response to a site’s particular temporal, physical and geographical conditions can be a means of de-programming everyday behavior and experience. Where it goes from there has more to do with the poetics of movement and human relationships than with any formal analysis of space. By following the example of art practices like Ceal Floyer’s and Gareth Moore’s I modify and subvert the orthodoxies of object-reliant practices and gallery-based works. My research furthers these ideas using every-day actions and materials in order to displace and challenge how contemporary art is exhibited, viewed, and archived. rough my work I seek to understand how to produce artwork that can be shown outside of and at the same time in conversation with a contemporary art context. I follow a similar approach in writing about my work in this document: I employ a casual and conversational way of talking about my practice as it develops over time. Often appropriating the materials and vernaculars of architecture, I create handmade, crudely constructed sculptural interventions that are simultaneously against and at one with a given environment. Drawing out both the physical and lyrical qualities of materials (usually mundane, practical materials such as concrete, textiles and ceramics), my work envisages an encounter, and foregrounds an action. It collapses and confuses the lines between process and product, doing and documentation.

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  • Productive Contemplation: Being In / Out of Place

    Forbes, Tabatha-Anne (2015)

    Doctoral thesis
    The University of Auckland Library

    The aim of this thesis is primarily to consider what the value of looking at and being in place means, and how that value may be interpreted through a 21st century art context. The devised methodology called ‘productive contemplation’ was used as a way of considering how we perceive place and how to be in place, while acknowledging significant historic and contemporary influences in both landscape painting and nature writing. The subsequent thesis includes observational writing, landscape photography and video making. The findings of the thesis clarified how the problematic dichotomy of being in / out of place is based on understanding the differences between its constructed and subjective view. This was explored particularly through a contemplative and empathetic discipline (and arts practice), informed by the research to develop as a more exploratory / metaphysical approach to being in place. Conclusively, the contemplative interpretation included an awareness of biodiversity, which became more current or active when understood in an environmental ethical context. Through an intimate portrayal of the two locations I was able to consider the value of being in place, in terms of how we are connected and simultaneously disconnected from it, and what the implications of that disconnection might mean, both in terms of how we inhabit place, and how we regard our ecological interdependence.

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  • A hard pill to swallow: Young women's experiences of taking antidepressants

    Wills, Celine (2015)

    Doctoral thesis
    The University of Auckland Library

    This research uses a narrative methodology to explore the experiences of young New Zealand women who have taken antidepressants, focusing on how these experiences affected their sense of self and how they understood their difficulties. This research is based on narrative interviews with 16 young women, aged 18-25, who used antidepressants. A narrative analysis compared the different types of narratives women used to describe their experiences and a thematic analysis considered patterns of meaning across their stories. The narrative analysis suggested that taking antidepressants affected these young women’s sense of self in a variety of different ways. Some narratives described antidepressant use as being able to restore or enhance participants’ sense of self and to assist them to meet normative expectations of young women. This narrative suggested the risk that young women might be forced to remain on antidepressants in order to maintain this valued self. For others, antidepressant use led to a view of themselves as either damaged, helpless, or no longer themselves. These narratives were accompanied by a sense of powerlessness and failure. In some cases, however, participants described increased agency as they rejected a biomedical conceptualisation of selfhood, and drew on more holistic or psychosocial understandings of selfhood instead. The thematic analysis highlighted the transformation that young women experienced in their understanding of themselves and their difficulties during antidepressant use. Antidepressants seemed to function to validate their distress but also resulted in the potential for an ‘illness identity’. Antidepressant use impacted on the women’s relationships with others. Participants tended to strive to find relationships in which they felt accepted for their choice to take antidepressants. Participants, however, tended to feel relatively powerless in their interactions with health professionals, which had a negative impact on their sense of self. The findings suggest that health professionals should acknowledge the impact of antidepressants on young women’s developing sense of self and strive to create a space where young women are able to make an informed choice about antidepressants.

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  • The Kopon: life and death on the fringes of the New Guinea Highlands

    Jackson, Graham (1975)

    Doctoral thesis
    The University of Auckland Library

    This thesis describes the Kopon of the lower Kaironk Valley, between the Bismarck and Schrader Ranges in Papua New Guinea. I compare the lower Kopon in certain respects with the upper Kopon, living further up the Kaironk Valley, and with the Kalam, living further up still. There are predominantly ethnographic chapters on the economy; groups; kinship; marriage, vital statistics, and migration; social control; supernaturalism; ritual; and taboo. The penultimate chapter discusses ritual, supernaturalism, and taboo, concentrating heavily on the latter, and the final chapter interrelates important aspects of material covered in the body of the thesis. The Kopon garden for the bulk of their food, but hunting and gathering contribute essential protein to the diet. The pig and the dog are domesticated. Settlement is dispersed, with houses handy to garden sites. Households are the largest moderately stable groups, but show some overlapping, and a degree of flux greater than would result from the demands of life cycle changes alone. Gardening groups, which range in size up to the equivalent of three or four households, show a high degree of overlapping and flux. The lower Kopon have a lower population density and a lower incidence of homicide than the upper Kopon or the Kalam, and there is a considerable down valley migration from upper to lower Kopon. Social control is on the basis of equivalence, self interest, and self help, and the only specialist role is that of curer. A higher mortality rate and richer natural resources in the lower than the upper Kaironk Valley plausibly explain much of the above. The high mortality keeps the population density relatively low, and encourages flux and overlapping of groups, both to guard against isolation should death occur, and to adjust to death when it does occur. This militates against the relatively clear-cut boundaries and undivided allegiance which would be to some extent necessary conditions for the existence of larger corporate groups. Superimposed on local flux in the lower Kopon is the down valley migration from the upper Kopon. This is a movement to an area of lower population density, richer resources, and attributable to these, lower rates of killing. Moving down valley to die may be a feature of populations on the fringes of the Highlands. Riebe (1974) has independently related the frequency of Kalam killings to population growth, these having increased in parallel from the mid-19th to the mid-20th century. In the relative absence of other indices of discrimination, the use of taboo as a marker has been developed to a high degree. Beliefs in the supernatural account for the processes of life, growth, healing, illness, and death, and the choice of a supernatural to which to attribute a natural death justifies either repaying the death with a killing, or letting it pass.

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  • If SWORD is the answer, what is the question? Use of the Simple Web service Offering Repository Deposit protocol

    Lewis, Stuart; Hayes, Leonie; Newton-Wade, Vanessa; Corfield, Antony; Davis, Richard; Wilson, Scott; Donohue, Tim (2009)

    Journal article
    The University of Auckland Library

    An open access copy of this article is available and complies with the copyright holder/publisher conditions. Purpose - To describe the repository deposit protocol, Simple Web-service Offering Repository Deposit (SWORD), its development iteration, and some of its potential use cases. In addition, seven case studies of institutional use of SWORD are provided. Approach - The paper describes the recent development cycle of the SWORD standard, with issues being identified and overcome with a subsequent version. Use cases and case studies of the new standard in action are included to demonstrate the wide range of practical uses of the SWORD standard. Implications - SWORD has many potential use cases and has quickly become the de facto standard for depositing items into repositories. By making use of a widely-supported interoperable standard, tools can be created that start to overcome some of the problems of gathering content for deposit into institutional repositories. They can do this by changing the submission process from a ‘one-size-fits-all’ solution, as provided by the repository's own user interface, to customised solutions for different users. Originality - Many of the case studies described in this paper are new and unpublished, and describe methods of creating novel interoperable tools for depositing items into repositories. The description of SWORD version 1.3 and its development give an insight into the processes involved with the development of a new standard.

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