971 results for Doctoral, 2015

  • Evolution Made Visible: The Worlds of Thomas Jeffery Parker (1850-1897) the Noted New Zealand Zoologist

    Crane, Rosemary Helen Beatrice (2015)

    Doctoral thesis
    University of Otago

    A biographical approach to the working life of Thomas Jeffery Parker FRS (1850-1897) provides scope for an in-depth investigation of how zoological knowledge became visible in late-nineteenth century New Zealand. A noted zoologist, Parker arrived in Dunedin in 1880 to a joint appointment as Professor of Biology in the University of Otago and Curator of the Museum. He had spent eight years working as demonstrator in Thomas Henry Huxley’s (1825-1890) laboratory in London. He brought with him a conviction that evolution provided the fundamental organising principle of biology. Once in Dunedin he set about making evolution visible. This study examines the various facets of Parker’s work that achieved this goal. I explore the lively debates arising from the public lectures he gave, in which he promoted evolution. In Dunedin, founded by Scottish Free Church Presbyterians in 1848, public interest in science-and-religion remained high throughout the late-nineteenth century. This study suggests that Parker’s own religious sensibilities lay between the agnosticism of Huxley and the faith of his Wesleyan father, the anatomist William Kitchen Parker (1823-1890). I also investigate Parker’s role in disseminating popular versions of biology, from the podium and through articles, to various audiences. His roles in the sociable side of scientific activities included organizing exhibits for conversaziones and international exhibitions. Parker’s efforts are placed within the context of Dunedin’s vibrant rational entertainment scene. Parker exchanged, bought, sold and collected specimens for the Otago University Museum in order to provide a comprehensive teaching collection. I appraise Parker’s previously little-understood role in museum collection building and explore his material practices in creating objects and their display according to evolutionary principles. Parker’s embryological studies of kiwi and phylogeny of the moa formed a major contribution to New Zealand biology. Methodologically speaking, he followed a traditional path of comparative anatomy. A close-reading of his more than forty papers of technically dense work reveal a conservative mind and a dedication to developmental morphology. Aware of changing epistemologies, he incorporated a statistical approach to his analyses. In this study, I suggest Parker created knowledge through drawing. Analysis of his illustrations reveals his concern with clear exposition. I show how the he used illustrations as part of the process of visual communication not simply as an adjunct. Generations of students learnt zoology using Parker’s system of ‘types’ a pedagogy he inherited from Huxley. They assimilated evolutionary principles via A Textbook of Zoology, which organized the animal kingdom in a typically late-nineteenth century progressive fashion. This two-volume book, co-authored with William Aitcheson Haswell (1854-1925) in Sydney and published posthumously, remains in print. An analysis of its creation shows how disciplinary shifts within zoology were fixed to the page. This study also uses Parker to explore wider concerns in the history of science. These include praxis and materiality, the popularization of science, the rise of the learned journal and broader aspects of print culture, and the geographic location of knowledge creation.

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  • Self-Regulation During A Reading-To-Write Task: A Sociocultural Theory-Based Investigation

    Wall, Bunjong (2015)

    Doctoral thesis
    University of Otago

    Most composition studies focus on students’ writing processes and written products without integrating reading into their research activities. More recently, researchers have acknowledged the reciprocal reading-writing relationship and begun to examine reading-to-write or discourse synthesis processes. Research shows that discourse synthesis is cognitively demanding and that most second language writers lack linguistic, mental, and sociocultural resources to perform this task effectively. Existing studies have not emphasised the role of self-directed speech as a self-regulatory strategy while students read multiple texts in order to write. This thesis addresses this gap in the literature. Informed by sociocultural theoretical notions that cognition is socially mediated and that speech is instrumental in learning and development, this qualitative multiple-case-studies thesis examined how five Thai EFL tertiary students applied their knowledge and skills, following explicit concept-based instruction on discourse synthesis, textual coherence, and argumentation. The researcher designed and delivered a four-week intervention in which the learning concepts, materials, and verbalisation were instrumental in promoting conceptual understanding and reading-to-write performance. Explicitly taught verbalisation or self-directed speech, together with learning materials specifically designed as schemes for task orientation, was a key for self-regulation as participants read multiple texts in order to compose an argument essay. The study adopted an activity theoretical framework and microgenetic analysis. The analysis aimed to describe the participants as social beings and to outline their self-regulation as it unfolded during a mediated reading-to-write activity. Data from a pre-task questionnaire on strategy use and from a post-task written self-reflection form together with video-recorded data during the end-of-intervention discourse synthesis task and interview data were triangulated to examine how reading-to-write activities were mediated and regulated. Findings were organised around four main themes: participants as readers and writers of English, essay argument structure, microgenetic findings of unfolding self-regulatory behaviour during the discourse synthesis activity, and developmental gains as perceived by the participants during concept-based instruction. The findings in this study show that participants’ reading and writing difficulties and argumentation were, in part, shaped by the social, historical and cultural factors in the Thai EFL context, and that participants’ strategic application of verbalisation and learning materials mediated their developmental changes and self-regulation. During the discourse synthesis task, participants used self-directed speech as a strategy and demonstrated varying degrees of self-regulation over various task aspects. Successful task completion indicated purposeful mediated learning with strong orientation towards the task, based on conceptual understanding, specific goals, and voluntary inclusion of learning materials as psychological tools. All participants reportedly viewed verbalisation as a useful strategy and most participants were able to describe their increased theoretical understanding of the concepts explicitly taught. However, their conceptual understanding did not always translate into their actual performance. These findings raise pedagogical implications and highlight the need for human mediators to make explicit the learning concepts, materials and strategies, so that theoretical understanding and learning tools can lead to meaningful task performance. Based on the above findings, this thesis proposes a self-regulation model and calls for future research to investigate how explicit verbalisation training can be systematised.  

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  • Hostility in the House of God: An "Interested" Investigation of the Opponents in 1 and 2 Timothy

    Thornton, Dillon T. (2015)

    Doctoral thesis
    University of Otago

    To my knowledge, Pietersen’s study (2004) is the only monograph published in the last twenty years that has focused on the opponents in the Pastoral Epistles, but his work is not exegetical. In this thesis, I concentrate on 1 and 2 Timothy, the two letters purportedly dispatched to Ephesus. I assemble the relevant pericopae of the letters and offer an exegetical analysis of them, with the intention of providing, first, a composite sketch of the ideology of the opposing group and, second, an in-depth account of the way the faithful Pauline community was to engage these opponents. The first chapter of the thesis is devoted to preliminary issues and methodology. I argue that 1 and 2 Timothy constitute two types of letter, both dispatched in the late first century to the Christian community in Ephesus, each addressing a stage of the conflict in which the community was engaged. I further argue that the polemical portions of the letters reveal specific information about this conflict. I then formulate a stringent method for the study of Paul’s opponents. I summarize and critique historical-critical methodologies and bring the most recent work on theological interpretation of Scripture into dialogue with these methodologies. The result is a new approach to the study of opponents, one that remains rigorously tethered to the primary text and that is characterized by ecclesial concern. In chapters two to six, I apply this method to 1 and 2 Timothy. In chapter two, I offer an exegetical analysis of the explicit units of 1 Timothy, those units where we have clear and certain reference to the opponents (1:3-7, 18-20; 4:1-5; 6:2b-5, 20-21a). Chapters three and four focus on the implicit units in 1 Timothy, those units where we have highly probable reference to the opponents (1:8-11; 2:9-15; 4:6-10; 5:9-16; 6:6-10). In chapter five, I turn to 2 Timothy, analyzing the three explicit units (2:14-26; 3:1-9; 4:1-5) and the one implicit unit of the letter (2:8-13). In chapter six, I bring together the full gamut of data uncovered in the exegetical chapters, offering overall conclusions about the opponents in 1 and 2 Timothy. As a follow-up to this, I enumerate what I perceive to be the most important implications of the findings for the house of God today. My findings may be summarized as follows. I conclude that the opponents came from within the Christian community in Ephesus and that their teaching is best described as an erroneous eschatological position that derived from the complexity of Paul’s views. Each doctrinal and ethical issue raised in the explicit and implicit units of the letters can be explained as a distortion of Pauline doctrine. Additionally, I contend that the opponents had an active “didactic/evangelistic ministry” in Ephesus, for which they received remuneration. They likely set out to recruit as large a following, and as large an income, as possible, but found a particularly fruitful field among the women in Ephesus. As I formulate my view of the opponents, I critique a number of the extant theories, including “Gnostic,” Jewish, and Proto-Montanist identifications. I also conclude that the author engages with the false teachers in significant ways throughout the letters. I draw attention to a number of literary and theological maneuvers that are intended to counteract the opponents’ influence and/or to bolster the faithful community’s confidence as they struggle against the opponents. These include the way the author turns features of the opponents against them, his use of the faithful saying formula, the way he relates the Triune God and the principal adversary, Satan, to the opponents, and the way the author portrays the gospel as an unstoppable force in his own ministry. Though the author pictures the opponents as enemies of God, he also highlights the fact that the opponents are not beyond the reach of God’s grace; thus, Timothy is called to minister the saving word to them. In the explicit and implicit units, the author instructs Timothy to occupy himself with five specific activities: reflection on his commissioning and on the apostolic gospel, rejection of the opponents’ claims, proclamation of the healthy teaching, demonstration of the gospel in actions that are pleasing to God, and correction of the false teachers themselves. The wider faithful community is at least implicitly included in the activities of rejection, demonstration, and correction.

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  • Public Theology, Core Values and Domestic Violence in Samoan Society

    Ah Siu-Maliko, Mercy (2015)

    Doctoral thesis
    University of Otago

    The purpose of this research is to formulate a theologically coherent perspective on the complex social and moral questions facing contemporary Samoan society. It does so by constructing a contextual Samoan public theology, based on the core Samoan-Christian values of alofa (love), fa’aaloalo (respect), soalaupule (consensual dialogue), tautua (selfless service) and amiotonu (justice). Drawing on scholarship on public theology, as well as relevant interdisciplinary sociological, cultural and religious studies, the thesis examines the nature and constituent elements of public theology, both in the West and in Samoa. To construct a framework for a public theology for Samoa based on its core values, the study examines the significance of the fa’asamoa (Samoan way of life) and its value system. Key to this framework is an understanding of the fusion between Samoan values and Christian values. Because ‘the public’ are the subjects of public theology, a crucial element of the construction of a Samoan public theology is the incorporation of the views of representative voices within Samoan society. Using constructivist grounded theory and talanoa Pacific research methodologies, seventy-five interviews from representatives of government, civil society, churches and villages garner valuable information on Samoans’ core values and their relevance for a public theology. The information on core values gleaned from research participants and other scholarship reveals how they can be brought to bear on social issues in the Samoan public sphere – the ‘why, who, what and how’ of a Samoan public theology. This collective knowledge suggests concrete ways of shaping theological discourse and moral action in contemporary Samoan society. The thesis ends with a contextual application of core Samoan-Christian values, as a public theology response to the social problem of domestic violence in Samoa.

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  • Enhancing the performance of wastewater microalgae through chemical and physical modifications in High Rate Algal Ponds

    Sutherland, Donna Lee (2015)

    Doctoral thesis
    University of Canterbury Library

    High rate algal ponds (HRAPs) are an advanced pond that provide efficient and cost-effective wastewater treatment, as well as the ability to recover nutrients in the form of microalgal biomass. Microalgal photosynthesis, nutrient uptake and subsequent growth, coupled with aerobic bacteria degradation of organic compounds, are fundamental to the process of wastewater treatment in HRAPs, yet are often limited in these ponds and, in particular, microalgal photosynthesis is well below the reported theoretical maximum. Understanding how the physico-chemical environment affects microalgal performance is therefore critical to improved wastewater treatment and nutrient recovery, yet has been the subject to few studies to date. This research focused on the enhancement of microalgal photo-physiology, growth and nutrient removal efficiency (NRE) through modification to the physical and chemical environment in wastewater HRAPs. In this study, I first examined the seasonal dynamics of microalgal performance in full-scale wastewater HRAPs. While both retention-time corrected chlorophyll biomass and photosynthetic potential increased from winter to summer, the summer-time performance was considered to be constrained, as indicated by the decreased light absorption, light conversion efficiency and NRE. The physico-chemical environment in the full-scale HRAPs were characterised by high day-time pH, high light attenuation and long, straight channels with low turbulence. This led to questions regarding 1) effects of nutrient supply, in particular carbon and 2) the role of the HRAP light climate on microalgal performance. I addressed these questions using a series of experiments that involved either changing the nutrient concentration and its supply or by modifying the light environment, through changes in pond operational parameters including CO2 addition, influent dilution, pond depth, hydraulic retention time (HRT), mixing speed and frequency. The overall results from these experiments showed that carbon was the primary and light the secondary limiting factors of microalgal performance. These limitations negatively affected light absorption, photosynthesis, productivity and NRE. While each operational parameter tested impacted on microalgal performance, to some degree, CO2 addition had the greatest influence on light absorption, photosynthetic efficiency and productivity, while continuous mixing had the greatest effect on NRE. Adding CO2 increased light absorption by 110% and 128%, maximum rate of photosynthesis by 185% and 218% and microalgal biovolume by between 150 – 256% and 260 – 660% (species specific), when cultures were maintained at pH 8 and 6.5, respectively. Providing sufficient mixing to achieve continuous turbulence enhanced NRE by between 300 – 425% (species specific), increased biomass concentrations between 150% and 4000% (species specific) compared to intermittent and no mixing, respectively, and increased harvest-ability of colonial species. However, at present, both CO2 addition and mechanical mixing attract high capital and operational costs. Modification to these technologies would be required to meet the objectives of cost-effective wastewater treatment and biofuel production. A more immediate and cost-effective solution demonstrated in this study was the altering pond depth, influent concentration and HRT. Doubling pond depth from 200 to 400 mm increased both microalgal nutrient removal and photosynthetic efficiencies which led to areal productivity increasing by up to 200%. When increased pond depth was coupled with decreased HRT, light absorption and photosynthetic performance further increased due to decreased internal self-shading and improved pond light climate. For nutrients, high influent loads increased productivity, while moderate loads increased effluent water quality. Overall, this work demonstrated that optimising the chemical and physical environment of wastewater treatment HRAPs (CO2 addition to maintain pH at 6.5 – 7, 400 mm pond depth, continuous mixing with vertical speed of 200 mm s-1, moderate nutrient load (15- 30 g m-3) and moderate HRT (4 / 6 days summer / autumn) can enhance microalgal biomass productivity, nutrient recovery as well as improve effluent water quality, particularly during summer when growth can be constrained.

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  • Puna kōrero: iwi and schools working together to support Māori student success

    Rewai-Couch, Melanie R (2015)

    Doctoral thesis
    University of Canterbury Library

    This thesis explores the notion that iwi and schools working together can contribute to culturally responsive curriculum and schooling. It investigates how some schools have formed genuine education partnerships with iwi, and provides answers to the following question: in what ways are iwi and schools working together to support Māori students? An understanding of communities of practice, and what Māori student success looks like, are essential. Imperatives for education partnerships and the educational policy, and drivers for partnership are foundational in understanding and connecting collaboration between iwi and schools with the wider educational picture in Aotearoa New Zealand. In New Zealand, Māori are not as successful as their non-Māori peers. Approaches to achieving education equity, including collaboration with iwi and Māori, is important for informing education approaches and strategy. How those approaches are informed, developed and implemented is equally important in achieving models likely to positively affect Māori achievement in education. This is also important in ensuring that participation expectations of iwi are co-constructed, reasonable and appropriately resourced. The theoretical base of this study draws upon the literature review on collaboration between Māori/iwi and the New Zealand education system, as well as international literature on supporting Indigenous students, using a community of practice approach. The metaphor of ‘puna kōrero’ is used in this research, as an approach allowing for consideration of different sites of investigation using an organic, kaupapa (issue, topic) Māori perspective. The three puna kōrero explored are Te Kauhua: A Ministry of Education funded professional development programme for schools and iwi; iwi voices: six iwi education representatives speak about their experiences working with schools and advancing their iwi education aspirations; Wai Study Help: an English-literacy programme operating in a kura kaupapa Māori (Māori immersion schooling) setting that has partnerships with its local university and iwi. From these puna kōrero, implications for iwi, schools and the Ministry of Education are considered. iii Exploration of the three puna kōrero identified passionate leadership and purposeful membership, funding and resourcing, monitoring and defining success, whakawhanaungatanga (nurturing relationships with others) and involvement of whānau (family) as key themes. Motivations for schools and iwi to work together are explored, along with rationale for the Ministry of Education’s support of iwi-school communities of practice. A framework for iwi-school communities of practice is proposed, including recommendations for iwi, schools and the Ministry of Education.

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  • Scalable and adaptable security modelling and analysis.

    Hong, Jin Bum (2015)

    Doctoral thesis
    University of Canterbury Library

    Modern networked systems are complex in such a way that assessing the security of them is a difficult task. Security models are widely used to analyse the security of these systems, which are capable of evaluating the complex relationship between network components. Security models can be generated by identifying vulnerabilities, threats (e.g., cyber attacks), network configurations, and reachability of network components. These network components are then combined into a single model to evaluate how an attacker may penetrate through the networked system. Further, countermeasures can be enforced to minimise cyber attacks based on security analysis. However, modern networked systems are becoming large sized and dynamic (e.g., Cloud Computing systems). As a result, existing security models suffer from scalability problem, where it becomes infeasible to use them for modern networked systems that contain hundreds and thousands of hosts and vulnerabilities. Moreover, the dynamic nature of modern networked systems requires a responsive update in the security model to monitor how these changes may affect the security, but there is a lack of capabilities to efficiently manage these changes with existing security models. In addition, existing security models do not provide functionalities to capture and analyse the security of unknown attacks, where the combined effects of both known and unknown attacks can create unforeseen attack scenarios that may not be detected or mitigated. Therefore, the three goals of this thesis are to (i) develop security modelling and analysis methods that can scale to a large number of network components and adapts to changes in the networked system; (ii) develop efficient security assessment methods to formulate countermeasures; and (iii) develop models and metrics to incorporate and assess the security of unknown attacks. A lifecycle of security models is introduced in this thesis to concisely describe performance and functionalities of modern security models. The five phases in the lifecycle of security models are: (1) Preprocessing, (2) Generation, (3) Representation, (4) Evaluation, and (5) Modification. To achieve goal (i), a hierarchical security model is developed to reduce the computational costs of assessing the security while maintaining all security information, where each layer captures different security information. Then, a comparative analysis is presented to show the scalability and adaptability of security models. The complexity analysis showed that the hierarchical security model has better or equivalent complexities in all phases of the lifecycle in comparison to existing security models, while the performance analysis showed that in fact it is much more scalable in practical network scenarios. To achieve goal (ii), security assessment methods based on importance measures are developed. Network centrality measures are used to identify important hosts in the networked systems, and security metrics are used to identify important vulnerabilities in the host. Also, new network centrality measures are developed to improvise the lack of accuracy of existing network centrality measures when the attack scenarios consist of attackers located inside the networked system. Important hosts and vulnerabilities are identified using efficient algorithms with a polynomial time complexity, and the accuracy of these algorithms are shown as nearly equivalent to the naive method through experiments, which has an exponential complexity. To achieve goal (iii), unknown attacks are incorporated into the hierarchical security model and the combined effects of both known and unknown attacks are analysed. Algorithms taking into account all possible attack scenarios associated with unknown attacks are used to identify significant hosts and vulnerabilities. Approximation algorithms based on dynamic programming and greedy algorithms are also developed to improve the performance. Mitigation strategies to minimise the effects of unknown attacks are formulated on the basis of significant hosts and vulnerabilities identified in the analysis. Results show that mitigation strategies formulated on the basis of significant hosts and vulnerabilities can significantly reduce the system risk in comparison to randomly applying mitigations. In summary, the contributions of this thesis are: (1) the development and evaluation of the hierarchical security model to enhance the scalability and adaptability of security modelling and analysis; (2) a comparative analysis of security models taking into account scalability and adaptability; (3) the development of security assessment methods based on importance measures to identify important hosts and vulnerabilities in the networked system and evaluating their efficiencies in terms of accuracies and performances; and (4) the development of security analysis taking into account unknown attacks, which consists of evaluating the combined effects of both known and unknown attacks.

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  • The regulation of 3-deoxy-D-arabino-heptulosonate 7 phosphate synthase from Mycobacterium tuberculosis.

    Blackmore, Nicola Jean (2015)

    Doctoral thesis
    University of Canterbury Library

    Allosteric regulation of important enzymes is a mechanism frequently employed by organisms to exert control over their metabolism. The shikimate pathway is ultimately responsible for the biosynthesis of the aromatic amino acids in plants, microorganisms and apicomplexans. Two enzymes of the pathway, 3-deoxy-D-arabino-heptulosonate 7-phosphate synthase (DAH7PS) and chorismate mutase (CM) are located at critical positions along the aromatic amino acid biosynthetic pathway and are often tightly feedback regulated in order to control the flux of metabolites through the pathway. This research presents studies on the allosteric function of these two enzymes. These studies emphasise the complexity of the intersecting network of allosteric response, which alters the catalytic activity of each enzyme in response to metabolic demand for the aromatic amino acids.

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  • Climate Variability: changing weather patterns over New Zealand

    Parsons, Simon (2015)

    Doctoral thesis
    University of Canterbury Library

    The original intention of this thesis was to investigate Climate Change (CC), in particular the meteorological impacts of CC on New Zealand (NZ). Succinctly, “to understand what NZ’s future weather may entail”. However, as the research progressed it has led to the larger circulation and has highlighted the teleconnections that are present and the importance of the wider circulation and to NZ . It is apparent that the larger scale circulation needs to be considered in conjunction with, if not before, the synoptic scale. Thus, in order to understand NZ’s future weather first we must understand the Southern Hemisphere and the circulation within it. CC is often described in a broad global scale and it is difficult to translate and relate these mechanisms into day to day weather terms, which have the advantage of being commonly understood. Synoptic Climatology (SC) can bridge this gap by simplifying the wide variety of weather into a small grouping of types, and thus can provide an understandable alternative. To undertake this research an existing SC scheme known as the Kidson Types (KTs) was extended with the use of General Circulation Model (GCM) output. The KTs have been widely used in NZ, thus work detailing their future would be advantageous. The GCMs were able to reproduce the observed frequencies of occurrence of the KTs during the late 20th century. Future projections for the late 21st century surprisingly showed little change in annual type frequencies. To investigate this further a sensitivity study was undertaken, which revealed that the methodology was insensitive to annual type frequency change. The range of response from the GCM projections also inhibited determining significant changes in KT frequencies. Additionally, trend analysis using four realisations from one GCM noted both positive and negative trends in some of the types. This also highlights the difficulty in using GCM output, as a larger ensemble can diffuse results and in a small ensemble individual GCMs can unduly bias the results. Further scrutiny of the KT was then undertaken. An investigation of the KTs to ascertain their influence in the wider circulation using the ERA Interim (ERA-I) reanalysis and trends within the KT using a long term reanalysis data set, the Twentieth Century Reanalysis (20CR). Due to the high year to year variability in the KTs, significant trends were only determined in the 20CR with a reduction in the Zonal Regime representing the occurrence of strong westerly flows over NZ. A composite analysis was also undertaken to evaluate the KTs within the Southern Hemisphere (SH). A positive pressure anomaly was detected far from the Kidson domain, which is defined over NZ, during the SW type. This motivated another study on SH Blocking. Blocking is a large scale phenomena that can influence the paths of synoptic systems and thus potentially cause or exacerbate adverse weather events. Blocking is an area of climate research that requires further work, as there is a deficit of GCM studies in the SH. This study utilised a Persistent Positive Anomaly (PPA) methodology which is advantageous as the spatial pattern, latitude and longitude, of the Blocking Events (BEs) is determined. To our knowledge, this is the first study to use GCM output using the PPA methodology in the SH and this is also the first blocking study using Coupled Model Inter-comparison Project (CMIP)5 GCM output in the SH. A reduction of BEs was observed over the South Pacific Ocean (SPO) region during summer and spring, in the GCM projections between 2041-2070 and 2071- 2100. The Southern Annular Mode (SAM) has been suggested as an influence on blocking frequency in previous work and this relationship was studied. A high negative correlation between SAM + and BEs was observed in summer with the reanalysis and GCM historical output. This correlation was reduced in 21st century. However, further work is needed in this study in order to gain an understanding of the mechanisms and linkages between SAM and the BEs.

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  • A multi-criteria approach to the evaluation of food safety interventions.

    Dunn, Alexander Hiram (2015)

    Doctoral thesis
    University of Canterbury Library

    New Zealand faces a range of food safety hazards. Microbial hazards alone were estimated to cause over 2,000 years of lost healthy life in 2011 (Cressey, 2012) and $62m in medical costs and lost productivity in 2009 (Gadiel & Abelson, 2010). Chemical hazards are thought to be well managed through existing controls (Vannoort & Thomson, 2009) whereas microbial hazards are considered harder to control, primarily due to their ability to reproduce along the food production chain. Microbial hazards are thought to cause the majority of acute foodborne gastroenteritis. This research reviewed food safety literature and official documentation, and conducted 55 interviews, mostly with food safety experts from different stakeholder groups, to examine the food safety decision-making environment in New Zealand. This research explores the concept of the ‘stakeholder’ in the context of food safety decision-making and proposes an inclusive ‘stakeholder’ definition as any group which is able to affect, or be affected by, the decision-making process. Utilising this definition, and guided by interviews, New Zealand stakeholders in food safety decision-making were identified and classified as follows: •Regulators •Public health authorities •Food safety scientists/academics •Consumers •Māori •Food Businesses (further classified as): o Farmers o Processors o Food retailers o Exporters Interviews with stakeholders from these groups highlighted twelve criteria as being relevant to multiple groups during food safety intervention evaluation: •Effectiveness •Financial cost •Market Access •Consumer Perceptions •Ease of Implementation •Quality or Suitability •Quality of Science •Equity of Costs •Equity of Benefits •Workplace Safety •Cultural Impact •Animal Welfare There are a number of different ways to measure or assess performance on these criteria. Some are able to be quantitatively measured, while others may require the use of value judgements. This thesis used the Disability-Adjusted Life Year (DALY) metric for quantifying effectiveness during the testing of different MCDA models. This thesis reviews the MCDA process and the food safety specific MCDA literature. There are different ways of conducting MCDA. In particular, there are a large number of models available for the aggregation phase; the process of converting model inputs, in the form of criteria scores and weights, into model recommendations. This thesis has described and reviewed the main classes of model. The literature review and interview process guided the construction and testing of three classes of MCDA model; the Weighted Sum, Analytic Hierarchy Process (AHP) and PROMETHEE models. These models were selected due to their having different characteristics and degrees of complexity, as well as their popularity in the food safety and Health Technology Assessment (HTA) literature. Models were tested on the problem of selecting the most appropriate intervention to address the historic Campylobacter in poultry problem in New Zealand during the mid-2000s. Experimentation was conducted on these models to explore how different configurations utilise data and produce model outputs. This experimentation included: •Varying the format of input data •Exploring the effects of including/excluding criteria •Methods for sensitivity analysis •Exploring how data inputs and outputs can be elicited and presented using visual tools • Creating and using hybrid MCDA models The results of this testing are a key output of this thesis and provide insight into how such models might be used in food safety decision-making. The conclusions reached throughout this research phase can be classified into one of two broad groups: •Those relating to MCDA as a holistic process/methodology for decision-making •Those relating to the specific models and mathematical procedures for generating numerical inputs and outputs This thesis demonstrates that food-safety decision-making is a true multi-criteria, multi-stakeholder problem. The different stakeholders in food-safety decision-making do not always agree on the value and importance of the attributes used to evaluate competing intervention schemes. MCDA is well suited to cope with such complexity as it provides a structured methodology for the systematic and explicit identification, recording and aggregation of qualitative and quantitative information, gathered from a number of different sources, with the output able to serve as a basis for decision-making. The MCDA models studied in this thesis range from models that are simple and quick to construct and use, to more time consuming models with sophisticated algorithms. The type of model used for MCDA, the way these models are configured and the way inputs are generated or elicited can have a significant impact on the results of an analysis. This thesis has identified a number of key methodological considerations for those looking to employ one of the many available MCDA models. These considerations include: •Whether a model can accommodate the type and format of input data •The desired degree of compensation between criteria (i.e. full, partial or no compensation) •Whether the goal of an analysis is the identification of a ‘best’ option(s), or the facilitation of discussion, and communication of data •The degree of transparency required from a model and whether an easily understood audit trail is desired/required •The desired output of a model (e.g. complete or partial ranking). This thesis has also identified a number of practical considerations when selecting which model to use in food safety decision-making. These include: •The amount of time and energy required of stakeholders in the generation of data inputs (elicitation burden) •The degree of training required for participants •How data inputs are to be elicited and aggregated in different group decision-making environments •The availability of MCDA software for assisting an analysis Considering the above points will assist users in selecting a suitable MCDA model that meets their requirements and constraints. This thesis provides original and practical knowledge to assist groups or individuals looking to employ MCDA in the context of food-safety intervention decision-making. This research could also serve as a guide for those looking to evaluate a different selection of MCDA models.

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  • Morphosyntactic development of typically- and atypically-developing Bangla-speaking children.

    Sultana, Asifa (2015)

    Doctoral thesis
    University of Canterbury Library

    Aims: Verb morphology, arguably, is identified as an area of exceptional challenge for the language development of both young typically-developing children, and children with language difficulties (Leonard, 2014a; Rice & Wexler, 2001). The developmental patterns of verb acquisition are found to be strongly governed by the typological properties of the ambient language; often language errors found in fusional languages (e.g. English and German) are significantly different from those found in agglutinative languages (e.g. Turkish and Tamil) (cf. Phillips, 2010). Therefore, the purpose of the study was to explore the developmental trends in the acquisition of verb morphology in Bangla, a language with agglutinative features. The first objective was to examine the morphosyntactic development of typically-developing (TD) Bangla-speaking children with regard to three verb forms, namely the Present Simple, the Present Progressive and the Past Progressive. A second objective was to examine the development of the three verb forms among a group of children with language impairment (LI). Rationale: Since Bangla is spoken by a large population, the acquisition data of Bangla represents a significant number of people, and the findings from the acquisition studies, when considered for intervention purposes, serve a considerably large population. Also, given that the normative data of language acquisition is unavailable for Bangla which leads to the absence of a language-specific assessment and intervention for LI children, the present study is expected to have importance for Bangla-speaking contexts. Method: Before the main study commenced, a pilot study was conducted with 19 Bangla-speaking TD children aged between two and four (years) in order to explore the developmental characteristics of the verb forms and to evaluate the research instruments identified for the actual study. The main study included 70 TD children between 1;11 and 4;3 years who were recruited from six daycare centres of Dhaka, Bangladesh. The children participated in three elicitation tasks, each to elicit one verb form, and a 20-minute play session that yielded a spontaneous language sample from each child. The researcher scored children’s performances on the three tasks, and transcribed the language samples using transcription software (Systematic Analysis of Language Transcripts). The elicitation tasks were used to determine children’s mastery of the forms, whereas the language samples were used to calculate a set of language measures associated with morphological development. The study also included a group of nine children with LI between 3;11 and 9;4 years who participated in the same set of tasks as the TD children. These children were recruited from a special school in Dhaka. Findings: The results revealed that, for both TD and LI children, the Present Simple form was acquired with highest accuracy which was followed by the scores in the Present Progressive and the Past Progressive forms respectively. The error patterns indicated a qualitative progress even in children’s errors, which was consistent with the accuracy rates of the target forms. Based on the TD children’s performance on the three tasks, a developmental sequence for the three Bangla verb forms was proposed. Results also identified that Mean length of Utterance (MLU) did not have stronger associations with the tasks scores than did Age. Among the determinants tested, Bound Morpheme Type (BMT) was identified to have the strongest associations with the task scores. Analyses of the data from the LI children revealed a significant difference between the TD and the LI children on all three tasks and the other language measures. When compared against the proposed developmental stages, the children within the LI group were found to different in terms of their morphosyntactic capacities. A sub-group of LI children also did not conform to any stages of typical development. Conclusions: Results of the present study offer directions for future investigations in a wide range of areas of Bangla morphosyntax that need to be examined with both TD and LI children. Moreover, factors associated with language development that the present study did not examine (e.g. the role of input) also need to be addressed in future studies. Above all, there is a strong need for ongoing investigations in order to identify a comprehensive picture of morphosyntactic development of Bangla-speaking TD children, which can then lead to the assessment of a range of language impairments in Bangla.

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  • The Influence of Music Congruence and Message Complexity on the Response of Consumers to Advertisements

    Seneviratne, Buddhakoralalage Leelanga Dananjaya (2015)

    Doctoral thesis
    University of Canterbury Library

    The overall aim of this study was to examine how the characteristics of two salient stimuli -music and message- of an audio advertisement influence the psychological state of consumers and how such a state subsequently determines their cognitive and affective responses to the advertisement. In achieving this aim, this study was guided by a combination of two cognitive resource utilisation theories, Limited Capacity Model of Motivated Mediated Message Processing (Lang, 2000) and Resource-Matching Hypothesis (Anand & Sternthal, 1989). In particular building upon inconsistency and load theories, this study proposed that certain stimulus characteristics prompted certain states of a consumer’s cognition. These two stimulus characteristics were the congruence of musical stimulus and the complexity of the message stimulus. The model then predicted the potential effect of these characteristics on certain psychological states (Psychological Discomfort and Cognitive Load) leading to affective (Attitude towards Advertisement) and cognitive (encoding, storage, and retention) responses. To empirically examine this model, an online experiment (using a 2 x 2 between-subject x 2 with-in subject mix design) was conducted, in which a mixed sample of 284 subjects was exposed to a set of audio advertisements especially designed for this study. Unfamiliar music in conjunction with a fictitious brand was used and the exposure level was maintained at low. ANCOVA, MANCOVA, two-stage hierarchical regression analysis, and Repeated-measures MANCOVA were administered to test the hypotheses presented in the conceptual model. Among major findings were that the multiple informational structures in a complex message positively influenced cognitive load, while congruent music was capable of attenuating the level of cognitive load. Incongruent music, on the other hand, was capable of generating a dissonance state experienced as psychological discomfort that in turn increased the level of cognitive load as a result of listener’s trying to resolve such a state. Both dissonance and cognitive load negatively influenced attitude towards advertisements, and the affect primacy of attitude formation appeared to be more applicable. Though high cognitive load clearly undermines encoding, storage, and retrieval processes, no evidence was found to support the Resource-matching Hypothesis. Furthermore, the findings suggested that the cognitive load offset by the congruent music would increase advertisement effectiveness by enabling its message to carry more information and by generating more favourable attitudes.

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  • Hydrodynamics and chemistry of silica scale formation in hydrogeothermal systems.

    Kokhanenko, Pavlo (2015)

    Doctoral thesis
    University of Canterbury Library

    The extraction of geothermal heat can cause precipitation of the minerals dissolved in geothermal fluid. Their deposition on the walls of wells and above-ground plant and in pores near reinjection wells, also known as mineral scaling, is one of the main obstacles to increasing the effectiveness of utilization of the limited geothermal resources. If not controlled properly it can result in accumulation of a significant amount of scale which obstructs pipes and reinjection wells and reduces the efficacy of heat exchangers. The most abundant mineral in geothermal fluid is silica and thus its precipitation can cause the highest scaling rate. While this dissertation is devoted to the study of silica scaling the results obtained may be applicable to other minerals with similar deposition mechanism. Oversaturated silica is known to precipitate from aqueous solution either by the direct chemisorption of single silicic acid molecules (monomers) or by forming colloidal particles suspended in the solution. These particles can subsequently be transported to, and attach onto, a wall. This process of colloidal silica deposition was previously recognised to cause much faster scaling than the direct deposition of silica monomers under typical geothermal plant conditions. While the chemical kinetics of silica polymerization and colloid formation are relatively well understood, transport of these colloids and their stability, which control their aggregation and attachment rates, on the other hand are not. Previous studies of the silica scaling process have identified prominent effects of geothermal brine hydrodynamics on the scaling rate. It was found to increase with the flow rate and particle size, thus suggesting the dominance of the advective (inertial) deposition of colloidal silica. However, this conclusion contradicted the present theory of particle transport in turbulent flows which argues the dominance of the diffusive transport for the relevant range of particle sizes (<1 μm). The development and continuing improvement of the anti-scaling measures required deeper understanding of the complex combination of the phenomena involved in the process of silica scaling. This was pursued in the present study using theoretical and experimental methods. First, the rate of colloidal silica transport from a turbulent flow onto the internal surface of a circular pipe, a cylinder and a flat plate were calculated using available analytical and numerical methods. The obtained theoretical transport rate was found to be about four orders of magnitude higher than the corresponding experimental scaling rate. The latter was determined in the previous studies to be 4.2·10-8 kg/s/m2 for silica colloids of 125 nm in diameter which corresponded to the dimensionless deposition velocity (the dimensionless deposition velocity is the scaling rate normalised by the particle mass concentration and friction velocity) of 1.2·10-6 for the dimensionless particle relaxation time of 2·10-4. Next, based on the standard DLVO theory of particle interactions and in the framework of the Smoluchowski approach the probability of colloidal silica particle attachment to a wall was found to be 10-6. Therefore, the theoretical scaling rate, calculated as a product of this probability and the above-mentioned transport rate was two orders of magnitude lower than the experimental scaling rate. This suggested that the implemented theoretical approach either underestimated particle transport rate or overestimated particle stability. Both possibilities are explored in this dissertation. In addition, the silica scaling rate was measured for a range of conditions: particle size from 20 to 60 nm, particle concentration 1600-10000 ppm, friction velocity from 0.09 to 0.18 m/s (Re = 9-50·103) and ionic strength from 30 to 80 mM, pH 8.1-9.5 and temperature from 25 to 44 °C. For this, laboratory experiments were designed and progressively modified in order to improve the repeatability of the results and to study the scaling process. In these experiments colloidal silica deposition onto the walls of mild steel pipe sections was studied with a recirculating flow rig with variable (but controllable) particle size, concentration, flow rate, pH and ionic strength of the solution. In addition, a parallel plate flow test section was designed and built which will provide better capabilities for the control over the hydrodynamic and test surface conditions in future experiments. The control over the chemical conditions was achieved by the use of the synthetic colloidal solutions. Two methods of their production – hydrolysis of either sodium metasilicate or active silicic acid – were employed. The influence of the synthesis conditions, ion content and pH on the long term behaviour of these colloidal solutions was investigated. The particle size data, obtained using dynamic light scattering (DLS) and verified by electron microscopy, was analysed and compared against the predictions of the current models of nanoparticle growth and stability. The kinetic aggregation was identified to be the dominant particle growth mechanism. Experimental data collected during the long-term observations of the particle growth allowed relationships between the aggregative stability and such parameters as the particle size, ion concentration and pH of the solution to be elucidated. In particular, the aggregative stability of 10-20 nm particles was found to be 108-1010 which is 7-9 orders of magnitude higher than the corresponding DLVO stability. It was also found to decrease with the increase of the particle size. This agreed with the theory of the colloid stabilization by steric interactions. Moreover, the model of the “gel” layer was used to explain the observed “anomalies” of the colloidal silica behaviour. The deposition experiments conducted with these synthetic colloidal solutions showed that the scaling rate increased with the particle size, flow rate and ionic strength (IS) of the solution. Thus, it was measured to be 9.7·10-9 kg/s/m2 for the 45 nm particles in a solution with IS = 0.05 M, which corresponded to the dimensionless deposition velocity of 6.6·10-8 for a dimensionless particle relaxation time of 2.2·10-6. The scaling rate was calculated for these conditions by multiplying the corresponding transport rate and the actual attachment probability determined as an inverse of the experimental stability. It was found to agree with the experimental value within an order of magnitude. In addition, the observed increase of the scaling rate with the increase of particle size was explained by the compensation of the decreased rate of the particle transport by faster decrease of actual particle stability (increase in attachment probability). Therefore the contradiction between the theory and the experiment was resolved for the particles of 20 to 60 nm in diameter. Moreover, the observations of the dimensions and distribution of the scale elements formed in some of the present experiments strongly suggested the significance of the advective (inertial) mechanism of particle deposition. This and comparative analysis of other experimental and theoretical data suggested that the present theory may underestimate the convective transport of the particles onto a rough wall. Therefore, the hypothesis of the parallel-to-wall advective deposition of the nanoparticles onto the roughness/scale elements (not accounted in the current theory) was proposed. The corresponding mass transfer problem was solved analytically using experimentally found dimensions of the scale elements. The additional transport was found to decrease the above-stated discrepancy between the theoretical and experimental scaling rate for large (125 nm) particles by one order of magnitude. The remaining difference of one order of magnitude was speculated to be due to the underestimation of these particles attachment probability derived with the standard DLVO theory. The actual aggregative stability of the silica colloids larger than 60 nm in diameter and for a wider range of IS values is of interest for future experimental studies. An improved understanding of the interrelation between the chemical and hydrodynamic phenomena in the process of silica scaling and its dominant mechanisms was achieved in this dissertation. This allowed optimization of the present anti-scaling practices aimed to minimize the negative effects of mineral scaling on the operation of geothermal power stations. Besides the practical recommendations, which may ultimately help to increase the efficiency of geothermal power stations, the results of the present study may be of value in the fields of mass transfer and colloid science.

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  • Development and optimization of an in vitro process for the production of Oryctes nudivirus in insect cell cultures

    Pushparajan, Charlotte (2015)

    Doctoral thesis
    University of Canterbury Library

    The coconut rhinoceros beetle, an economically important pest of coconut and oil palms, is effectively managed by application of its natural pathogen, the Oryctes nudivirus (OrNV), which act as a bioinsecticide. While this approach offers an environment-friendly alternative to chemical pesticides, the current method of production in infected larvae suffers from inconsistencies in virus productivity and purity. While the anchorage-dependent DSIR-HA-1179 insect cell line has been identified as a susceptible and permissive host for OrNV and therefore would be suitable for the in vitro mass production of the virus, no attempts have been made toward the mass production of the virus, because of the technological challenges that working with DSIR-HA-1179 cells represent. Thus, the main objective of this research was to develop processes for the in vitro production of OrNV in the DSIR-HA-1179 cell line. Knowledge of the growth kinetics and metabolic properties of the host cell line in a chosen culture medium, as well as the selection of an appropriate infection strategy, form the basis for the rational development of bioreactor-based virus production processes. However, characterization of these properties in the DSIR-HA-1179 cell line has been virtually precluded, due to its strongly adherent growth characteristics and the lack of a reliable method to accurately dissociate and count cells grown in monolayers. Using TrypLE™ Express enzyme, a technique allowing the precise counting of cells was developed. The cell line was adapted to grow in four serum-supplemented culture media: TC-100, IPL-41, Sf-900 II and Sf-900 III, which were then individually screened for cell growth and virus production in 25 cm2 attached T-flask cultures. TC-100 supplemented with 10% fetal bovine serum was chosen as a suitable culture medium, based on its capacity for achieving a high cell yield and OrNV production. The cell line metabolism was characterized with respect to nutrient consumption and metabolites production in this culture medium. Glucose, along with glutamine were found to be the nutrients that were consumed faster and to a greater extent, while other amino acids were not consumed to a significant degree. The production of metabolites was characterized by non-production of lactate and ammonia, and production of alanine, as a non-toxic alternative to ammonia. The influence of cell density (CD) at time of infection (TOI) and multiplicity of infection (MOI) on OrNV production was evaluated in T-flask cultures that were infected at different CDs at the TOI and a range of MOIs. The CD at TOI was found to significantly influence OrNV yields, while MOI influenced the dynamics of infection. The cell density effect was found to exist for the DSIR-HA-1179/OrNV system with the progressive decline in cell-specific yield beginning at low cell densities. It was found that in order to maximize OrNV volumetric yield, a combination of MOI and CD at TOI should be selected that allows to keep the maximum cell density reached by the infected culture within a range between 5.0 and 7.0 x 105 viable cells/ml. The roller bottle system was evaluated for its potential to scale-up DSIR-HA-1179 cell growth and OrNV production, and culture parameters were optimized for the improvement of cell and virus yields. An inoculum density of 3.3 x 105 cells/ml and culture volume of 60 ml resulted in the highest cell yield of 1.5 x 106 cells/ml, in 490 cm2 roller bottles. It was found that an optimal infection strategy for roller bottle cultures, which represented the most efficient use of viral inoculum, involved infecting cells at a density of 5.0 x 105 cells/ml and at a MOI of 1. The resulting OrNV volumetric yield of 2.5 x108 TCID50/ml, improved significantly the viral yields obtained in attached T-flask cultures infected under similar conditions (6.8 x 107 TCID50/ml). The microcarrier system was also evaluated for culturing DSIR-HA-1179 cells and producing OrNV in spinner flask bioreactors. Three types of microcarriers (Cytodex-1, Cytodex-3 and Cultispher-G microcarriers) were screened for their ability to support DSIR-HA-1179 growth. Cells attached to Cytodex-1 and 3, but failed to attach to Cultispher-G microcarriers. The final cell density reached in microcarrier culture was dependent on bead type and concentration, and the cell to bead ratio. At an optimal bead concentration of 1 mg/ml and cell to bead ratio of 30, cells grew to a maximum density of 1.7 x 106 cells/ml on Cytodex-1, but only to 1.3 x 106 cells/ml on Cytodex-3 microcarriers. Since it supported higher cell yields, Cytodex-1 was chosen to study the kinetics of OrNV production in this system. Microcarrier cultures infected at a cell density of 5.0 x 105 cells/ml and a MOI of 1, produced OrNV at 1.4 x 108 TCID50/ml, which was higher than the yield obtained in T-flask cultures infected under similar conditions. A framework of knowledge on the physiology, metabolism and growth kinetics of the DSIR-HA-1179 insect cell line has been developed in this thesis. In addition, the feasibility of using roller bottles and microcarrier systems for the in vitro production of the virus has been ascertained. It is envisaged that these findings will contribute to the future development of a large-scale industrial process for the production of the OrNV biopesticide.

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  • Gold-based Nanomaterials: Spectroscopy, Microscopy and Applications in Catalysis and Sensing

    Adnan, Rohul (2015)

    Doctoral thesis
    University of Canterbury Library

    The birth of nanotechnology era has revolutionized materials science, catalysis and field of optoelectronics. Novel and unique phenomena emerge when material dimensions are reduced to ultra-small size regime and enter nanometre (2-100 nm) realm. Such novel materials are expected to replace bulk materials, offering lower cost of manufacturing and enabling progress in many areas such as solar cell, drug delivery, quantum communication and computing, catalysis and sensing applications. With the progress in nanomaterial synthesis and fabrication, the need for the state-of-art characterization techniques became obvious; such techniques help to establish a complete understanding of the nature and interactions of nanosized materials. In this thesis, the first part focuses on the synthesis of gold and ruthenium clusters, namely Au8, Au9, Au101, Ru3, Ru4 and AuRu3, using the well-established synthetic protocols in the literature. Apart from the standard lab-based characterization techniques such as nuclear magnetic resonance (NMR), UV-visible spectroscopy (UV-vis) and Fourier Transform Infra-red (FTIR), a less explored but useful technique far infra-red (far IR) spectroscopy, available at the Australian Synchrotron (AS), was employed to investigate the vibrational modes in these clusters. Peaks in the experimental far IR spectra were assigned unambiguously to specific vibrations by comparing with the ones generated via DFT calculations with the help of collaborators, group of Professor Gregory Metha, University of Adelaide. For the Au9 cluster, three significant gold core vibrations are observed at 157, 177 and 197 cm-1 in the experimental spectrum. In the case of the Ru3 cluster, only a single ruthenium core vibration is identified within the spectrum, at 150 cm-1 with the calculated force constant, k = 0.33 mdyne/Å. The Ru4 cluster exhibits two metal core vibrations at 153 and 170 cm-1 with force constants of 0.35 and 0.53 mdyne/Å, respectively. Substitution with a gold atom yielding a mixed metal AuRu3 cluster shifts the core transitions toward higher wavenumbers at 177 and 299 cm-1 with an increase in force constants to 0.37 and 1.65 mdyne/Å, respectively. This is attributed to the change in chemical composition and geometry of the metal cluster core. A combination of the DFT calculations and high quality synchrotron-based experimental measurements allowed the full assignment of the key transitions in these clusters. Next, these clusters were fabricated into heterogeneous catalysts by depositing on different metal oxide nanopowders. Synchrotron X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) studies were performed at the Australian Synchrotron and the Photon Factory synchrotron in Japan to investigate the electronic structure of Au8, Au9 and Au101 on TiO2 catalysts. The XPS analysis reveals that “as-deposited” Au8 and Au9 retain some un-aggregated clusters while Au101 show bulk-like gold. These findings are in line with TEM observations, where the aggregates (large particles, > 2 nm) of Au8, Au9 and Au101 are hardly seen under HRTEM. UV-visible diffuse reflectance spectroscopy (UV-vis DRS) studies show the absence of localised surface plasmon resonance (LSPR) peaks in these “as-deposited” clusters, suggesting they are below 2 nm in size. Importantly, the XAS spectrum of “as-deposited” Au9 clusters estimates that 60% of pure, un-aggregated Au9 clusters and 40% of bulk gold in the sample. Upon calcination under O2 and combined O2 and H2 (O2-H2), Au8, Au9 and Au101 clusters form larger nanoparticles (> 2 nm) with the appearance of LSPE peak in UV-vis DR spectra. In addition, majority of the phosphine ligands (that stabilise the gold core) dislodge and form phosphine oxide-like species by interacting with oxygen on the TiO2 surface. The third part focused on testing the catalytic performance of the supported Au8, Au9, Au101, Ru3, Ru4 and AuRu3 clusters on different TiO2, SiO2, ZnO and ZrO2 in benzyl alcohol oxidation. Au101-based catalysts display the highest catalytic activity with a turn-over frequency (TOF) up to 0.69 s-1. The high catalytic activity is attributed to the formation of large Au nanoparticles (> 2 nm) that coincides with the partial removal of capping ligands. Au8 and Au9 clusters which contain NO3- counter anions are found to be inactive in benzyl alcohol oxidation. Further work shows that the presence of NO3- species diminishes the catalytic activity. Monometallic ruthenium clusters, Ru3 and Ru4, are found to be inactive yet the bimetallic AuRu3 clusters are active in benzyl alcohol oxidation, suggesting the synergistic effect between ruthenium and gold metal. Investigation of catalytic testing parameters reveals that tuning selectivity of the product is possible through manipulating the reaction temperature. Finally, a joint experiment with Prof. Wojtek Wlodarski’s group at RMIT, Melbourne was undertaken to test the sensing ability of Au9 clusters for hydrogen detection. Au9 clusters were deposited onto radio-frequency (RF) sputtered WO3 films at two different concentrations; 0.01(S1) and 0.1(S2) mg/mL. It was found that the optimal temperatures for sensor S1 and S2 were 300 °C and 350 °C, respectively. The sensor with lower Au9 concentration (S1) displays a faster response and recovery time, and a higher sensitivity toward H2. HRTEM studies reveal that the sensor S1 contain a significant population of sub-5 nm Au nanoparticles which might be responsible for a faster rate of H2 adsorption and dissociation. The key finding in this study suggest that the addition of catalytic layer such as ultra-small Au9 clusters results in improved sensitivity and dynamic performance (response and recovery time) of H2 sensors. In summary, this thesis demonstrated that cluster-based nanomaterials have wide range of applications spanning from catalysis to sensing. Further improvements in material synthesis and use of multiple complimentary characterization techniques allowed better understanding of the nature of the key active species (metal nanoparticles) assisting design of catalysts and sensors with enhanced performance.

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  • Investigation and Prediction of the Sound Transmission Loss of Plywood Constructions

    Wareing, Robin Richard (2015)

    Doctoral thesis
    University of Canterbury Library

    The sound transmission loss of a range of plywood panels was measured to investigate the influence of the orthotropic stiffness of the plywood panels. The plywood panels were tested as single and also double leaf partitions, with a range of stud configurations. A new method was developed for predicting the sound transmission loss of single leaf partitions with both orthotropic and frequency dependent stiffness values. The sound transmission loss was evaluated for two significantly different sample sizes. The observed influence of the sample size on the measured sound transmission loss was profound. The construction of the partition was shown to significantly affect the influence of the sample size on the sound transmission loss. A qualitative analysis based on existing published research of the contributing factors is presented, and methods for adjusting the results for the small sample size for comparison with the large results were developed. The influence of a range of acoustic treatments of lightweight plywood partitions was investigated. The treatments involved internal viscoelastic materials and decoupled mass loaded barriers in various arrangements. The attachment between the treatment and the plywood panel was found to influence the sound transmission loss significantly. A prediction method based on published models was modified to allow the influence of the treatments to be included. Reasonable agreement was achieved between the predicted and measured results for a wide range of samples. A prediction method was developed that accounts for the influence of orthotropic, frequency dependent material parameters. This method utilised an adaptive, numerical integration method to solve an analytical formulation for the sound transmission loss. The influence of the finite sample size was accounted for using an expression for the finite panel radiation impedance. The finite panel radiation impedance was predicted analytically and an approximation was also presented. The presence of a significant source room niche was accounted for by applying an appropriate limit to the integration range of the angle of incidence. The prediction methods developed are compared with the measured transmission loss results from both the small and large test facilities. Good agreement was seen for some of the predicted results. Generally the agreement within the coincidence region was worse than for the rest of the transmission loss curve. The inclusion of orthotropic and frequency dependent stiffness values significantly improved the agreement within the coincidence region.

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  • El camino se hace caminando: Using Participatory Action Research to evaluate and develop Peace Education practice in a Secondary School in Northern Nicaragua

    Kertyzia, Heather (2015)

    Doctoral thesis
    University of Otago

    Peace education (PE) is included in the cross-curricular themes of the Nicaraguan curriculum, yet in the Secondary School in Northern Nicaragua (SSINN) where this research was conducted there was varied implementation by teachers. The SSINN was selected for this research due to particular problems with violence. Based on a critical and post-development theory perspective and using participatory action research (PAR) methodology, teachers, school psychologists and administrators were led through a facilitated process of reflection upon the culture of peace/violence in the SSINN and teacher practice. This was guided by the concepts of education about (content), for (skills and behaviours) and by peace (pedagogy). PAR is guided by a series of principles that allow for flexibility and response to participant needs. In this case SSINN educators and I engaged in a process of building trust, gathering reconnaissance data, developing action plans and taking action. This was guided by our unofficial motto ‘the path is made by walking’ (el camino se hace caminando), implying that we were learning as we worked together and the process had to be adaptable to new circumstances. Through workshops and coffee chats we evaluated staff definitions of a culture of peace, priorities in relation to peace values, behaviours and content, and teacher practice in regards to peace principles. As part of the reciprocal process, educators gave feedback and directed the research, which was designed to emphasize educator voice and minimize the neo-colonial imposition of values from outside actors. In this way I sought to balance critical theory’s need to take action for positive change with post-development theory’s prioritizing of local educator voice. The primary goals of the research were to develop an understanding of how PE was practised in the SSINN and, if the educators requested it, to provide support in taking positive action for change, while assessing the effectiveness of the PAR methodology. In the beginning the educators had differing definitions of a culture of peace, but they were very consistent in their ideas of what content, skills and values should be included in PE. Although they regularly mentioned problems that were directly relevant to students’ lives that should be addressed in the classroom, not all of the teachers were actively doing this. Due to a lack of resources, time, teacher stress and overcrowding, many teachers were unable to translate those ideas into action. Also due to those factors, many teachers fell into habits of traditional teaching practice that were inconsistent with peace pedagogy. Recognizing these issues, the teachers requested workshops on non-violent communication and conflict transformation in the hope that that knowledge would aid them to more positively manage behaviour. They also created and implemented an action plan. Although positive steps were taken, this was the first stage of a long-term process of change. Partnering with local non-governmental organizations (NGOs) has provided the possibility of the continuation of the process; nevertheless those NGOs have stated that they need continued external support. This flexible PAR methodology was effective at exploring and developing PE practice in the SSINN, and has the potential, if continued, to lead to fundamental positive change.

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  • A multi-modal device for application in microsleep detection

    Knopp, Simon James (2015)

    Doctoral thesis
    University of Canterbury Library

    Microsleeps and other lapses of responsiveness can have severe, or even fatal, consequences for people who must maintain high levels of attention on monotonous tasks for long periods of time, e.g., commercial vehicle drivers, pilots, and air-traffic controllers. This thesis describes a head-mounted system which is the first prototype in the process of creating a system that can detect (and possibly predict) these lapses in real time. The system consists of a wearable device which captures multiple physiological signals from the wearer and an extensible software framework for imple- menting signal processing algorithms. Proof-of-concept algorithms are implemented and used to demonstrate that the system can detect simulated microsleeps in real time. The device has three sensing modalities in order to get a better estimate of the user's cognitive state than by any one alone. Firstly, it has 16 channels of EEG (8 currently in use) captured by 24-bit ADCs sampling at 250 Hz. The EEG is acquired by custom-built dry electrodes consisting of spring-loaded, gold-plated pins. Secondly, the device has a miniature video camera mounted below one eye, providing 320 x 240 px greyscale video of the eye at 60 fps. The camera module includes infrared illumination so that it can operate in the dark. Thirdly, the device has a six-axis IMU to measure the orientation and movement of the head. These sensors are connected to a Gumstix computer-on-module which transmits the captured data to a remote computer via Wi-Fi. The device has a battery life of about 7.4 h. In addition to this hardware, software to receive and analyse data from the head-mounted device was developed. The software is built around a signal processing pipeline that has been designed to encapsulate a wide variety of signal processing algorithms; feature extractors calculate salient properties of the input data and a classifier fuses these features to determine the user's cognitive state. A plug-in system is provided which allows users to write their own signal processing algorithms and to experiment with different combinations of feature extractors and classifiers. Because of this flexible modular design, the system could also be used for applications other than lapse detection‒any application which monitors EEG, eye video, and head movement can be implemented by writing appropriate signal processing plug-ins, e.g., augmented cognition or passive BCIs. The software also provides the ability to configure the device's hardware, to save data to disk, and to monitor the system in real time. Plug-ins can be implemented in C++ or Python. A series of validation tests were carried out to confirm that the system operates as intended. Most of the measured parameters were within the expected ranges: EEG amplifier noise = 0.14 μVRMS input-referred, EEG pass band = DC to 47 Hz, camera focus = 2.4 lp/mm at 40 mm, and total latency < 100 ms. Some parameters were worse than expected but still sufficient for effective operation: EEG amplifier CMRR ≥ 82 dB, EEG cross-talk = -17.4 dB, and IMU sampling rate = 10 Hz. The contact impedance of the dry electrodes, measured to be several hundred kilohms, was too high to obtain clean EEG. Three small-scale experiments were done to test the performance of the device in operation on people. The first two demonstrated that the pupil localization algorithm produces PERCLOS values close to those from a manually-rated gold standard and is robust to changes in ambient light levels, iris colour, and the presence of glasses. The final experiment demonstrated that the system is capable of capturing all three physiological signals, transmitting them to the remote computer in real time, extracting features from each signal, and classifying simulated microsleeps from the extracted features. However, this test was successful only when using conventional wet EEG electrodes instead of the dry electrodes built into the device; it will be necessary to find replacement dry electrodes for the device to be useful. The device and associated software form a platform which other researchers can use to develop algorithms for lapse detection. This platform provides data capture hardware and abstracts away the low-level software details so that other researchers are free to focus solely on developing signal processing techniques. In this way, we hope to enable progress towards a practical real-time, real-world lapse detection system.

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  • Electronic Conduction in Disordered Carbon Materials

    Cheah, Chun Yee (2015)

    Doctoral thesis
    Victoria University of Wellington

    Graphene, consisting of a single layer of carbon atoms, is being widely studied for its interesting fundamental physics and potential applications. The presence and extent of disorder play important roles in determining the electronic conduction mechanism of a conducting material. This thesis presents work on data analysis and modelling of electronic transport mechanisms in disordered carbon materials such as graphene. Based on experimental data of conductance of partially disordered graphene as measured by Gómez-Navarro et al., we propose a model of variable-range hopping (VRH) – defined as quantum tunnelling of charge carriers between localized states – consisting of a crossover from the two-dimensional (2D) electric field-assisted, temperature-driven (Pollak-Riess) VRH to 2D electric field-driven (Skhlovskii) VRH. The novelty of our model is that the temperature-dependent and field-dependent regimes of VRH are unified by a smooth crossover where the slopes of the curves equal at a given temperature. We then derive an analytical expression which allows exact numerical calculation of the crossover fields or voltages. We further extend our crossover model to apply to disordered carbon materials of dimensionalities other than two, namely to the 3D self-assembled carbon networks by Govor et al. and quasi-1D highly-doped conducting polymers by Wang et al. Thus we illustrate the wide applicability of our crossover model to disordered carbon materials of various dimensionalities. We further predict, in analogy to the work of Pollak and Riess, a temperature-assisted, field-driven VRH which aims to extend the field-driven expression of Shklovskii to cases wherein the temperatures are increased. We discover that such an expression gives a good fit to the data until certain limits wherein the temperatures are too high or the applied field too low. In such cases the electronic transport mechanism crosses over to Mott VRH, as expected and analogous to our crossover model described in the previous paragraph. The second part of this thesis details a systematic data analysis and modelling of experimental data of conductance of single-wall carbon nanotube (SWNT) networks prepared by several different chemical-vapour deposition (CVD) methods by Ansaldo et al. and Lima et al. Based on our analysis, we identify and categorize the SWNT networks based on their electronic conduction mechanisms, using various theoretical models which are temperature-dependent and field-dependent. The electronic transport mechanisms of the SWNT networks can be classed into either VRH in one- and two-dimensions or fluctuation-assisted tunnelling (FAT, i.e. interrupted metallic conduction), some with additional resistance from scattering by lattice vibrations. Most notably, for a selected network, we find further evidence for our novel VRH crossover model previously described. We further correlate the electronic transport mechanisms with the morphology of each network based on scanning electron microscopy (SEM) images. We find that SWNT networks which consist of very dense tubes show conduction behaviour consistent with the FAT model, in that they retain a finite and significant fraction of room-temperature conductance as temperatures tend toward absolute zero. On the other hand, SWNT networks which are relatively sparser show conduction behaviour consistent with the VRH model, in that conductance tends to zero as temperatures tend toward absolute zero. We complete our analysis by estimating the average hopping distance for SWNT networks exhibiting VRH conduction, and estimate an indication of the strength of barrier energies and quantum tunnelling for SWNT networks exhibiting FAT conduction.

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  • Investigating the mode of action of tuberculosis drugs using hypersensitive mutants of Mycobacterium smegmatis

    Campen, Richard Laurence (2015)

    Doctoral thesis
    Victoria University of Wellington

    Mycobacterium tuberculosis, the etiological agent of tuberculosis (TB), is the leading cause of death and disease by a bacterial pathogen worldwide. The growing incidence of drug resistant TB, especially multi-drug resistant TB highlights the need for new drugs with novel modes of action. Current treatment of TB involves a multi-drug regimen of four drugs including isoniazid and rifampicin, both of which were discovered over 40 years ago. Bedaquiline is one of the first novel TB drugs to enter clinical trials since the discovery of rifampicin, and has shown excellent activity against drug resistant TB. Although isoniazid and rifampicin are well established anti-TB drugs, significant gaps in knowledge regarding their modes of action exist. Furthermore, little information on the mode of action of the novel drug bedaquiline is known beyond its primary target. Characterisation of drug mode of action facilitates rational modifications of drugs to improve the treatment of TB. The aim of this study was to identify novel aspects of the modes of action of isoniazid, rifampicin, and bedaquiline by characterising drug hypersensitive mutants of M. smegmatis mc²155. A sub-saturated M. smegmatis mc²155 transposon mutant collection with 1.1-fold genome coverage (7680 mutants) was constructed, with this collection estimated to contain mutations in 73.2% of all genes capable of maintaining a transposon insertion (non-essential genes). A high-throughput assay was developed for screening the collection, and mutants related to known drug mode of action were identified for isoniazid (ahpC and eccCa₁) and bedaquiline (atpB). Additionally, known mechanisms of drug inactivation were identified for isoniazid (nudC), rifampicin (arr and lspA), and bedaquiline (mmpL5). The finding that transposon mutants of nudC are hypersensitive to isoniazid independently validated the recent discovery of the role of NudC in basal isoniazid resistance by Wang et al. (2011). The remaining genes identified in this thesis represent potentially novel aspects of the modes of action or resistance mechanisms of these drugs. Cross-sensitivity to other drugs indicated that the mechanism of sensitivity was drug specific for the mutants examined. Differential-sensitivity testing against drug analogues revealed that Arr is involved in resistance to the rifampicin analogue rifapentine as well, indicating that Arr can detoxify rifapentine similar to rifampicin. The nudC mutant showed increased sensitivity to a range of isoniazid analogues, indicating that it can detoxify these analogues similar to the parent compound. Interestingly six analogues were found to be less active against the nudC mutant than expected. A number of overexpression strains were tested against these six analogues; a nudC overexpression strain, and a strain overexpressing inhA, the primary target for isoniazid. Overexpression of nudC as well inhA increased the resistance of WT to isoniazid, but failed to increase resistance to three of the analogues, NSC27607, NSC33759, and NSC40350. Isoniazid is a prodrug and is activated by the peroxidase/catalase enzyme KatG. Overexpression of katG resulted in increased isoniazid sensitivity, as well as increased sensitivity to NSC27607, NSC33759, and NSC40350. Together these results suggest that NSC27607, NSC33759, and NSC40350 are activated by KatG, but that InhA is not the primary target. Additionally the inability of NudC overexpression to confer resistance suggests these analogues are not acting via a NAD adduct, the mechanism by which isoniazid inhibits InhA. These results suggest that there are other toxic metabolites being produced by KatG activation of these three analogues. In conclusion, characterisation of mutants identified in a high-throughput assay for drug hypersensitivity identified genes involved in the modes of action or resistance mechanisms for isoniazid, rifampicin, and bedaquiline. Additionally, a number of novel genes were identified that have no known connections to the known modes of action or resistance mechanisms for these drugs. Further testing of a nudC mutant revealed three isoniazid analogues that appear to inhibit growth of M. smegmatis mc²155 independent of InhA, the primary target of isoniazid. This study has successfully demonstrated that screening for drug hypersensitivity can generate novel information on drug mode of action and resistance mechanisms. This information can ultimately be used to help drive the development of new drugs, and improve treatment of TB.

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