840 results for University of Waikato, Doctoral

  • The collectors : Naval, Army and Air Intelligence in the New Zealand Armed Forces during the Second World War

    Tonkin-Covell, John (2000)

    Doctoral thesis
    University of Waikato

    This thesis examines the performance of the intelligence collection organisations of the armed services of New Zealand during the Second World War. It considers the intelligence bodies of the Navy, the Army and the Air Force and looks at their growth, development and demise, and assesses their effectiveness as intelligence organisations. The question of how much New Zealand could be expected to achieve in the field of intelligence arises, not least because New Zealand was demographically small, had a long coastline and was geographically relatively remote. How much could New Zealand contribute to the Allied cause in intelligence terms is another issue, and what forms did any participation take? Were there lessons to be learned from the wartime experience (there were, but they went for the most part largely unheeded)? New Zealand, like other countries, had a fragmented approach to intelligence collection, making for a degree of complexity over a range of activity, despite the intelligence organisations being of modest size. The examination of the organisations in this thesis includes multi-service and multi-departmental dimensions along with the production of useful intelligence. Whether good use was made of intelligence collected is another matter. There was a substantial amount of liaison, contact and practice between departments of state as to various aspects of intelligence, the Organization for National Security and coastwatching being two notable areas. The overarching role and limitations of the Organization for National Security with regard to intelligence is explored, and the development of a combined intelligence centre examined. The participation of New Zealand signals intelligence organisations in the great Allied interception offensive is detailed, along with the mundane but fundamental task of coastal surveillance. The establishment and spectacular decline of the first local independent security service is traced. Both the intelligence and security aspects of the Army's operationally deployed units are covered, along with the growth of RNZAF air intelligence. The effectiveness of all of these organisations could hardly be expected to be uniform, and indeed it was not. Some bodies succeeded in their collection roles beyond expectations, others were reasonably effective, and two organisations failed dismally in different ways, for a number of reasons. If a pattern emerges at all, it is that small single service component-type intelligence sections collecting operational intelligence were the most effective New Zealand intelligence organisations. Operational focus and. operational requirements underlay the drive for successful collection. Most significant within the Allied context were the signals intelligence bodies. At the other end of the scale, larger co-operative interdepartmental New Zealand intelligence ventures failed to deliver projected results. New Zealand's armed forces had an interesting variety of intelligence contributions during the Second World War. Of these, the most effective organisations collected intelligence to meet directed operational requirements.

    View record details
  • Development of an aluminium filled epoxy insert using perfactory rapid prototyping technique and electroless nickel plating for low volume plastic injection moulding

    Rajaguru, Janaka Chandraguptha (2015)

    Doctoral thesis
    University of Waikato

    In this research, a rapid tool for low volume production plastic injection moulding is designed, developed, and tested on an injection moulding machine. The tool is designed as a cavity insert of injection mould for plastic parts by an indirect rapid tooling approach. The plastic part is modelled in a CAD system and then built using a Perfactory rapid prototyping (RP) technique. Then a layer of nickel-phosphorous alloy is deposited on the prototype by electroless plating. This nickel plated RP model is then used as a casting pattern. A cavity insert, which is produced by using aluminium filled epoxy resin with the nickel plated casting pattern, is fabricated in a mould base for injection moulding. Experimental testing on the cavity insert using an injection moulding machine show that the tool is producing quality parts without any noticeable deterioration of the surface. The number of shots completed using the cavity insert is more than 600. Applying electroless nickel plating on the casting pattern made of rapid prototyping material was successful. It was found that pre-treatment processes are crucial. In addition, the rapid prototyping material cannot be plated with nickel without palladium activation and stannous sensitising. Results show that the deposited layer is uniform and composed of both nickel and phosphorous. The surface properties of the nickel and phosphorous deposit enhance the plated layer performance due to their low surface roughness and high lubrication characteristics. Moreover, the nickel-phosphorous layer also improves the surface hardness of the cavity insert since it is left on the cavity after the removal of the casting pattern. The cavity insert was installed on an industrial injection moulding machine for trials. Results show that the cavity insert performs well with Polyethylene at 170˚C at an injection pressure in the range of 80 ~ 100 bar. There are no signs of wear and tear on the cavity insert up to 620 shots. However, when the injection pressure is over 120 bar, cracks start developing in the cavity insert followed by catastrophic fracture. This research has shown that manufacturing an indirect rapid tooling using electroless nickel plating for low volume production of plastic injection mouldings is feasible for Perfactory produced RP models. The cavity insert can be fabricated using commonly available low cost materials within 48 hours.

    View record details
  • Portfolio of Compositions: Systematic composition of cross-genre hybrid music

    Mayall, Jeremy Mark (2015)

    Doctoral thesis
    University of Waikato

    The research focus of this PhD thesis is the development of a new technique for composing original musical compositions in which elements from different musical genres are hybridised. The innovative aspect of achieving balanced hybridity is the development of a systematic approach to selecting and synthesising or hybridising key musical elements across a range of different genres. The major component of this submission is a portfolio of nine original works with attached CD/DVD recordings. 1. Tracking Forward for viola, backing track and video 2. The Long White Cloud for chamber band and electronics 3. ‘Colorless green ideas sleep furiously’ for orchestra 4. Push for Miles for electric bass and backing track 5. Norse Suite for viola and cello 6. The Foggy Field a studio construction 7. Into the Nocturnal Sunshine for flute, viola, cello, drums and electronics 8. One Night, New Breath for taonga puoro, viola, drums and electronics 9. Sketches of an Intergalactic Earworm for piano trio and boombox The accompanying documentation clarifies, and contextualises the creation and presentation of these works; and illuminates the aesthetic underpinnings and compositional techniques developed and utilised as a part of this hybrid-genre compositional approach. The structure of the supporting exegesis is in two parts: the methodology of practice-based research, and reflective investigation. Part One (Chapters 1 and 2) is an introductory overview; an observation of the existing literature and related work, relevant creative practice in the composer’s previous work; and the compositional methodology – including an explanation of the genre matrix. Part Two (Chapters 3 to 12) analyses the use of genre, the balance of hybridity, and relevant compositional techniques utilised in the development of each individual piece.

    View record details
  • A New Form of Authoritarianism? Rethinking Military Politics in Post-1999 Nigeria

    Adeakin, Ibikunle Edward (2015)

    Doctoral thesis
    University of Waikato

    Despite the vast research that has been done on the Nigerian military, virtually all of these studies have failed to critically examine the accepted role of the military in the democratising phase. This is important because the relationship between the political elite and the military in post-military authoritarian states guarantees either democratic consolidation, or its reversal. In Nigeria, despite an appearance of significant progress in subordinating the military institution to democratic civilian authority, the military remains a crucial political actor in the polity. It appears that the military has yet to accept the core democratic principles of civilian oversight of the institution. This thesis, therefore, explores whether a new form of military authoritarianism is emerging in Nigeria, with the aim of understanding Nigeria’s military behaviour in a transitional phase, from prolonged military authoritarianism to democratisation. To examine this military behaviour, Alfred Stepan’s concept of military prerogatives that was used to understand the military’s behaviour in a transitional phase in Latin America is applied to Nigeria. A crucial understanding of authoritarianism in Nigeria is initially discussed in this study using mainly document analysis strategy to examine whether multi-ethnic states, such as Nigeria, tend to have authoritarian systems. Six hypotheses form the core analysis of this thesis: first, that the military has retained significant military prerogatives; second, that retired military officers are gaining influential political and economic positions; third, autonomous military involvement in human rights abuses since 1999; and fourth, that civilian government oversight remains weak, and facilitates military authoritarianism. These hypotheses are primarily analysed using the elite interview technique. During the first half of 2011, the author conducted field research where serving and retired military officers were interviewed. The fifth hypothesis is that the military has intervened in politics post-1999. The examination of this hypothesis relies primarily on key security-related media reports (mostly newspaper editorials) on the military after 1999. The examination of the final hypothesis, that increases in military expenditures might facilitate a new form of military authoritarianism, relies primarily on descriptive statistical analysis. In addition, this study collated relevant historical materials that relate to the military, utilising national archival collections. The empirical findings of this research did not identify a new form of military authoritarianism in Nigeria. The study, however, argues that the unrestricted institutional framework accorded the military has contributed significantly to authoritarian practices in the post-military era in Nigeria. This study discovered that there were similarities between the Brazilian and Nigerian militaries in regard to their military spending during their period in power. Both countries had lower defence budgets. Just as in Brazil, it appears that part of the reason the Nigerian military decided to relinquish power in 1999 had to do with its desire to gain a higher budget, something that was precluded in a military government struggling to retain a sense of legitimacy. The military needed a higher budget to modernise and re-professionalise its institution after more than a decade in power. This feature, which the Nigerian military shares with the Brazilian military, appears to justify the application to Nigeria of Alfred Stepan’s concept of military prerogatives.  

    View record details
  • Heterosexual couples, gender discourse, and the production of relational subjectivity

    Morris, Brian (2015)

    Doctoral thesis
    University of Waikato

    This study is situated in feminist and poststructural theory. The focus of the study is heterosexual relationships. In particular, the study investigates the shaping effects of patriarchal discourses on the relational subjectivity of a woman partner; how a woman partner responds to and refuses this shaping; and why and how a man might change his positioning in relation to his partner. The data were generated through focus group discussions with women, and individual interviews with men. An initial women’s focus group generated core data for analysis, which was followed by interviews with men, and then a final focus group of women. Documentary practices, derived from narrative therapy, were used to capture and bridge discussions between these three stages of data generation. A poststructural analysis investigated the production of relational subjectivity in the context of heterosexual relationships. Analysis of data included a focus on relational subjectivity as reported by one of the initial focus group women. A deconstructive analysis of material from the initial focus group showed the shaping of women’s relational subjectivities at the intersection of dominant patriarchal and resistant practices. This deconstructive analysis is supported by analyses of material from the men’s interviews, and from the final focus group of women. Further, based in knowledge generated from the initial women’s focus group, an idea for heterosexual relationship as egalitarian is developed in the analysis. The thesis argues that heterosexual relationship is often dominated by patriarchal ideas and practices that privilege the male partner. The thesis offers a philosophical location with the potential to reposition heterosexual relationship to a safe and egalitarian place. An exploration is offered about how men might take up ethical practices so that the repositioning of heterosexual relationship can be maintained, and patriarchally sustained male privilege held accountable. The thesis suggests that the ethical ideas and practices offered for egalitarian heterosexual relationship might be extrapolated to gender relations in general. My accountability as a male researcher is embedded in the process of the study, with feminist supervisors, in the research methodology with the final focus group of women, and in critical reflexivity in the data analysis. In particular, an example is provided which shows the researcher reflexively analysing one moment in the data generation where a research participant was offered a possible non-preferred position. The contribution of this study is to bring Derridean ideas on ethical action to relational subjectivity in heterosexual relationship. Its timeliness is evidenced by the demand from the women participants, and others, for men to engage in respectful and ethical relationship practices. At the same time the study argues that its timeliness is still in the making, produced in the democracy to come that is being brought into existence when the potential for respectful and ethical relationship is enacted in practice. The responsibility for inventing such practices rests with men.

    View record details
  • Economic Valuation of Water Quality Improvements in New Zealand

    Mkwara, Lena Asimenye (2015)

    Doctoral thesis
    University of Waikato

    Efficient decision making in environmental management requires good data on the costs and benefits of changes in environmental quality. However, full assessment of the benefits of better water quality has been a challenge because some of the component values cannot be directly measured. The advent of non-market valuation techniques has made it possible to estimate these values. In this thesis, the travel cost random utility model and fishing choice data from the National Angling Survey are used to assess the benefits of better water quality for trout anglers in the Rotorua Lakes and a choice experiment is used to assess the benefits of cleaner streams for Karapiro catchment residents. We also explore three methodological aspects which may affect non market value estimates, namely within season variability, scale heterogeneity across individuals and respondent perceptions of the status quo. Accounting for within-season variability in site attributes that are variable across the season may reduce multicollinearity. We find that differences in welfare estimates between models accounting for within-season variability and those that do not may result from differences in attribute and collinearity levels or the combined effect of both. We assess whether benefit estimates remain stable over time using models that account for scale heterogeneity across individuals and demonstrate that ignoring scale heterogeneity across the sampled population may result in researchers erroneously concluding that estimates of marginal willingness to pay are stable over time. A choice experiment on preferences for stream water quality is used to assess the effects of respondent’s perception of status quo conditions on welfare estimates. The results build on earlier findings which suggest that failure to take account of respondents’ beliefs leads to biased welfare estimates. Overall we find that lakes with better water clarity, that are larger in size, with bigger fish, more facilities and more forest cover are preferred. Similarly, streams with water quality that is suitable for swimming and where trout are found, are preferred. We estimate the aggregate annual benefit for anglers of a one metre increase in water clarity in all the Rotorua Lakes which currently have poor or average water water quality to be NZ$2.3 million. The travel cost RUM is also used to assess the overall benefit that trout anglers obtain from each lake. The annual level of these benefits totals NZ$21.7 million.

    View record details
  • Realising Value: Study-Related Support-Seeking Experiences

    Supramaniam, Sivakumari (2015)

    Doctoral thesis
    University of Waikato

    The idea of ‘exchange’ in Service Dominant Logic’s (S-D logic) Foundational Premise (FP) 1 (service is ‘exchanged’ for service) has retained the residual transactional concept from Goods Dominant Logic (G-D logic) as the basis of understanding of service in S-D logic. This has limited the processual understanding in S-D logic; in particular, the need to understand value as a process rather than an output. This study meets that need in presenting a holistic understanding of the individual’s valuing process for S-D logic. An interdisciplinary search of literature beyond the discipline of marketing on the term ‘valuing’ was conducted in the fields of psychology, education, and systems thinking. This study investigates how students with disabilities realise value through study-related support-seeking experiences. Sixteen students with disabilities, who were enrolled in higher educational services in New Zealand, participated in this study. A phenomenographic approach was applied to understand the variations in ways that students with disabilities experienced and understood the support-seeking phenomenon. The variations and similarities in meanings were abstracted as categories of description. Four categories of description of Knowing, Understanding, Judging, and Acting represented participants’ conceptions of experiencing the support-seeking phenomenon. Each category of description outlined both the variations in meanings and the structural aspects of experiencing the phenomenon. The four categories of description were logically displayed in an outcome space - a hermeneutical spiral - to portray the different ways of experiencing the support-seeking phenomenon. The hermeneutic spiral provides a holistic understanding of the valuing process for S-D logic’s view of service as a process. Hence, value is not a perceptual state at an endpoint of time, rather it is a here-and-now snapshot ‘taking stock’ in a dynamic process. The second contribution this study makes to S-D logic relates to the processual understanding of value. In the process of valuing, the participants were experiencing and understanding the support-seeking phenomenon in relation to their mental acts, or structural awareness, at a moment of time. Thus, participants appreciate, and act upon their thoughts. This builds on the S-D logic’s Foundational Premise (FP) 10 that the beneficiary always uniquely and phenomenologically determines value. Specifically, the second contribution of this research relates directly to the insights revealed by the phenomenography method into variations in participants’ experiences of support-seeking. The research provides sound empirical support for valuing as a dynamic process, which extends the FP10 notion of value as a static valuation at a particular point in time. Along with the S-D logic contributions, this study contributes phenomenography as a research method that is little known in marketing. This method has the potential to understand the variations of individuals’ realities as experienced. The practical implication of this study adds to knowledge of support-seeking behaviour as an avenue for businesses to engage in people’s appreciation and be of service to them.

    View record details
  • Analysing and Enhancing the Coarse Registration Pipeline

    Larkins, Robert L. (2015)

    Doctoral thesis
    University of Waikato

    The current and continual development of sensors and imaging systems capable of acquiring three-dimensional data provides a novel form in which the world can be expressed and examined. The acquisition process, however, is often limited by imaging systems only being able to view a portion of a scene or object from a single pose at a given time. A full representation can still be produced by shifting the system and registering subsequent acquisitions together. While many solutions to the registration problem have been proposed, there is no quintessential approach appropriate for all situations. This dissertation aims to coarsely register range images or point-clouds of a priori unknown pose by matching their overlapping regions. Using spherical harmonics to correlate normals in a coarse registration pipeline has been shown previously to be an effective means for registering partially overlapping point-clouds. The advantage of normals is their translation invariance, which permits the rotation and translation to be decoupled and determined separately. Examining each step of this pipeline in depth allows its registration capability to be quantified and identifies aspects which can be enhanced to further improve registration performance. The pipeline consists of three primary steps: identifying the rotation using spherical harmonics, identifying the translation in the Fourier domain, and automatically verifying if alignment is correct. Having achieved coarse registration, a fine registration algorithm can be used to refine and complete the alignment. Major contributions to knowledge are provided by this dissertation at each step of the pipeline. Point-clouds with known ground-truth are used to examine the pipeline's capability, allowing its limitations to be determined; an analysis which has not been performed previously. This examination allowed modifications to individual components to be introduced and measured, establishing their provided benefit. The rotation step received the greatest attention as it is the primary weakness of the pipeline, especially as the nature of the overlap between point-clouds is unknown. Examining three schemes for binning normals found that equiangular binning, when appropriately normalised, only had a marginal decrease in accuracy with respect to the icosahedron and the introduced Fibonacci schemes. Overall, equiangular binning was the most appropriate due to its natural affinity for fast spherical-harmonic conversion. Weighting normals was found to provide the greatest benefit to registration performance. The introduction of a straightforward method of combining two different weighting schemes using the orthogonality of complex values increased correct alignments by approximately 80% with respect to the next best scheme; additionally, point-cloud pairs with overlap as low as 5% were able to be brought into correct alignment. Transform transitivity, one of two introduced verification strategies, correctly classified almost 100% of point-cloud pair registrations when there are sufficient correct alignments. The enhancements made to the coarse registration pipeline throughout this dissertation provide significant improvements to its performance. The result is a pipeline with state-of-the-art capabilities that allow it to register point-cloud with minimal overlap and correct for alignments that are classified as misaligned. Even with its exceptional performance, it is unlikely that this pipeline has yet reached its pinnacle, as the introduced enhancements have the potential for further development.

    View record details
  • The Formulation of Titanium - based Metal Feedstocks and the Fabrication of Parts using the Powder Injection Moulding Process

    Ewart, Paul Douglas (2015)

    Doctoral thesis
    University of Waikato

    Development of a profitable titanium industry for New Zealand will not come about without innovative technologies. Plastic injection moulding has long held a place in NZ manufacturing to produce large quantities of complex parts and holds the key to such innovation. Titanium metal parts were fabricated by injection moulding titanium based metal powder feedstock followed by a debinding process and subsequent sintering. The fabrication process in its entirety was investigated in four distinct steps. Feedstock formulation involved combining the metal powders with various carrier components. Injection moulding enabled the shaping of the feedstock into geometries approximating the final part. Debinding being the process whereby the carrier/binder system is removed from the part to create a powder compact retaining the required geometry. Sintering being the final step where the metal powders are consolidated into a fully dense metal part of net shape. The feedstock binder consisted of water soluble polyethylene glycol that reduced feedstock viscosity, improved particle wetting, aided greenpart shape retention and eliminated toxic solvents in debinding. Carnauba wax and bees wax aided dispersion, lubricated particles, were safe to handle and better for the environment (than petroleum waxes). Their low melt temperatures aided removal during thermal debinding and supported residue elimination. By optimising the ratio of water soluble, wax and polyolefin binder components (3: 2: 1 respectively) for melt flow and pellet formation, greenparts defect free with uniform particle distribution were made. The optimal binder system proved suitable for titanium alloy and irregular shape pure titanium powders (hydride-de-hydride). Increasing powder loading (wP = (0.60 to 0.65)) had no appreciable effect on viscosity while enabling feedstock with good uniformity and pellet formation. Dimensional change was not affected by uniformity of the feedstock however molecular weight, volume and dispersion of binder components affected interparticular distances. Low processing temperatures reduced disruption to part geometry, benefitted particle bonding and helped retain handling strength. The use of low temperatures for thermal debinding (t = 250 °C) enabled removal of the binder below the temperatures that facilitate interstitial diffusion and oxide/carbide formation, although part thickness, mass and overall volume effected the processing time. A strong correlation was seen between handling strength of the greenparts and defects, such as non-uniform density distribution and cracking after sintering. Sintering was essential to produce the final part and showed that a binder free brownpart was not the only criteria for eliminating impurities. The furnace atmosphere must remain free from contamination to eliminate transfer back to the parts. This was addressed using an argon sweep gas, however, the design and efficacy of the system was considered inadequate. Decomposition products need to be removed quickly from the furnace as they evolve before impurities from the sweep gas diffuse back into the parts during the extended duration at sinter temperatures (t = 1300 °C). The combination of an optimised titanium feedstock and the use of a low temperature thermal debinding technique produced a consolidated MIM part of relatively large dimensions. The parts were seen to have uniform microstructure throughout the cross-section with density comparable to that of MIM standards. In difference to the literature, a high powder loading (φp = 0.65) of HDH powders was used and shown to be readily mouldable. The higher powder loading also eliminate separation defects and shape distortions evident using lower amounts of powder.

    View record details
  • Governance of International Rivers: Threats, Gaps and Challenges

    Raman, Durgeshree Devi (2015)

    Doctoral thesis
    University of Waikato

    In light of the growing water shortages world-wide and concerns over freshwater disputes arising from essentially a growing world population, an increase in per-capita consumption and the limited supplies of freshwater resources, this thesis looks at issues of governance of international rivers in terms of threats to them, gaps in their governance regimes and challenges associated with closing those gaps. International river basins globally are currently threatened with over-extraction, pollution, damming and infrastructural development as well as the impact of climate change. If left unaddressed, the pressure on the international river basins, as riparian States compete for its limited supplies, is only going to exacerbate any chances of freshwater disputes between them. The United Nations Convention on the Non-Navigational Uses of International Watercourses offers a guidance framework to enable riparian States of international rivers to achieve ‘equitable utilization’ of water resources as well as management of the basin in order to avoid freshwater disputes. This thesis analyses the adequacy of the Convention to address the four main threats. The analysis is supplemented by the Berlin Rules, international cases and arbitral awards. The thesis has also undertaken a study of the European regional framework as an example of best regional practice, given that it not only has a similar Convention to the UN Watercourses Convention being the United Nations Economic Commission for Europe’s Convention on the Protection and Use of Transboundary Watercourses and International Lakes, but it also has other pieces of legislative and policy documents to guide the European Union States to achieve the paramount objective of the EU water policy, which is ‘good ecological status’ for all its water bodies by 2015. This is to ensure sustainable water supply for its current and future populations. In order to test the viability of the UN Watercourses Convention against individual basin’s legal regimes, the thesis has taken the Jordan, the Nile and the Indus River Basins as case studies as they are already considered to be ‘hot spots’ for freshwater disputes and the four main threats to them, which if not adequately addressed, will only aggravate the already existing tension. The analysis of the case studies’ legal regimes involve an examination of the extent of the specific threats in each river basin and the strengths and weaknesses of each governance regime in order to ascertain where it is lacking. In order to enable an international legal framework that is apt to guide riparian States to deal with any of the four main threats to any international river basin, this thesis proposes recommendations for changes to the UN Convention based on other sources of international law and policy, the EU framework as well as the strengths of the governance regimes of the case studies. In order to minimize any chances of freshwater disputes and increase water security in the case studies, the thesis also makes recommendations for improvement to each legal governance regime based on international law and policy, the EU framework as well as the strengths of the governance regime of the other case studies. In doing so, this thesis provides a comprehensive overview of the current international law, policy, case law and arbitral awards relating to each major threat that has been identified. It also highlights the progress being made in addressing these threats in the European region through the practical application of the relevant treaties, directives and policy documents. Finally, it puts together the legal responses that are required to effectively address the four main threats in the Jordan, the Nile and the Indus River Basins.

    View record details
  • Elucidating the Origin of Tetrodotoxin in Pleurobranchaea maculata and Stylochoplana sp.

    Salvitti, Lauren R. (2015)

    Doctoral thesis
    University of Waikato

    Tetrodotoxin (TTX) is an extremely potent neurotoxin that acts by selectively targeting voltage gated sodium channels blocking propagation of action potentials. Long believed to be present only in pufferfish, TTX has now been detected in a wide range of phylogenetically unrelated terrestrial and aquatic taxa. Despite decades of research the exact origin of TTX remains a mystery. Current literature supports three hypotheses: endogenous, symbiotic bacteria, or bioaccumulation through a dietary source. In 2009, the opisthobranch Pleurobranchaea maculata (grey side-gilled sea slug) was found to contain high concentrations of TTX in New Zealand. A large collaborative project, of which my research was a major part of, was initiated to explore the origin of TTX in P. maculata. During extensive benthic surveys conducted to identify possible dietary sources of TTX, high concentrations (ave. 380 mg kg-1) were detected in Stylochoplana sp. (Platyhelminthes) from Pilot Bay (Tauranga, New Zealand). Tetrodotoxin concentrations were found to vary temporally, peaking between June and August. The co-occurrence of Stylochoplana sp. and P. maculata in Pilot Bay raised the possibility that Stylochoplana sp. could be a dietary source of TTX for P. maculata. A real-time PCR assay was developed, and detected Stylochoplana sp. in seven out of nineteen P. maculata foreguts. Symbiotic bacterial production of TTX in the tissues of P. maculata and Stylochoplana sp. was also explored. Isolated strains (102; 17 unique strains - identified using 16S rRNA gene analysis) were analyzed using a recently developed method to detect the C9 base of TTX. In addition to enhanced sensitivity, this method has the advantage that it might detect precursor and degradation products. To explore the possibility that TTX is produced by a consortium of bacteria, experiments were undertaken where homogenized tissue was spiked into marine broth and samples were collected over two weeks for toxin and molecular analysis. No C9 base or TTX production was detected in isolates or from bacterial communities, suggesting that a symbiotic microbial source of TTX is unlikely in these organisms. The ability of non-toxic P. maculata to sequester TTX from an environment known to contain toxic populations of the same species was also assessed. Sixteen non-toxic specimens were kept in mesh cages (eight anchored to the benthos and eight suspended 0.5 m above it) for eight weeks and fed a non-toxic food source. Toxin analysis revealed that more ‘benthic’ specimens (4 verses the 2 from suspended specimens) sequestered TTX and were shown to retain higher concentrations (max. 0.79 versus 0.43 mg kg-1). These data suggest a localized microbial source of TTX that is more readily available from the benthos. Diet analysis, utilizing next generation sequencing of toxic and non-toxic P. maculata identified their diet comprised a wide array of organisms, with Thelepus sp. and Plumularia sp. being prevalent in toxic individuals, and further testing of these organisms is suggested. Lastly, immunohistological methods, employing a monoclonal antibody targeting TTX, were conducted with tissues from P. maculata and Stylochoplana sp.. Strong TTX signals were detected in the mantle and oocytes of P. maculata and the ova and pharynx of the Stylochoplana sp.. These data suggest ecological roles for TTX including: defense in adults, protection in progeny, and prey capture in Stylochoplana sp.. A synthesis of the studies presented in this thesis, and those that were conducted as part of the larger project, are also presented and future studies to elucidate the origin of TTX in New Zealand taxa are suggested.

    View record details
  • Performative Methodologies: Geographies of Emotion and Affect in Digital Storytelling Workshops

    Bliss, Elaine (2015)

    Doctoral thesis
    University of Waikato

    This thesis advocates digital storytelling as a geographical methodology to understand how emotion and affect are produced. Digital storytelling is a flexible and workshopped methodology that captures experimental, creative and imaginative performances of emotion and affect. Through digital storytelling geographers may build understandings of how emotion and affect are experienced individually and collectively. I use 11 digital storytelling workshops, with more than 100 participants, as the primary sites for my research. The workshops were conducted in the United States and New Zealand and were modelled on the practice established by the Center for Digital Storytelling in Berkeley, California, United States. It is argued that digital storytelling workshops co-create emotion, affect, people and place. Individual and group interviews, reflexive autobiographical journal writing, and digital storytelling workshop training, participation, and observing are used to access emotion and affect in digital storytelling workshops. A combination of qualitative research methods and critical social theories are used to highlight embodied, emotional and affectual geographies. Three findings frame my discussion. First, digital storytelling workshops are performative spaces for the staging and circulation of emotion and affect. The concepts of infrastructure, improvisation, and intimacy are critical for understanding the dynamic nature of emotion and affect in digital storytelling workshops. Second, a focus on relationality allows for an examination of psychotherapeutic practice and the transformative capacity of digital storytelling workshops. Workshop spaces are understood as ‘connective mediums’ in which a third position – the gap between the flow of emotions and the representation of that experience - is possible. Third, voice in digital storytelling is a political process of speaking and listening. A focus on voice permits an exploration of the acoustic politics of emotion and affect at individual and collective spatial scales. Digital storytelling workshops facilitate processes of seeing, hearing and experiencing emotion and affect as a way of interpreting the geographical worlds of research participants. The Center for Digital Storytelling’s model incorporates a commitment to social justice that honours and values emotional knowledge. As a practice-based research methodology digital storytelling requires researchers to be reflexive and negotiate their multiply layered ethical positionings. As geographers continue to experiment with innovative ways of conducting research, the messiness of digital storytelling can contribute to methodological debates about the ‘doing’ of emotion and affect in geographical research.

    View record details
  • Meaningful Witnessing in the United States, India & New Zealand: The Possibility Space for Digital Video Within Human Rights, Protest Movements and Activist Practices

    Lenzner, Benjamin (2015)

    Doctoral thesis
    University of Waikato

    This dissertation examines the emergence of digital video practices rooted in human rights, social justice issues and protest movements through a number of select case studies in the United States, India and New Zealand. This project analyzes and critiques the formation of digital video practices through the lens of Manuel DeLanda’s interpretation of assemblage theory. Examining interactions between crucial elements present in a possibility space that aid in the cultivation and assembling of budding forms of digital video, this study considers the implications in the relationships between both material and expressive qualities of these assemblings. The central argument of this thesis asserts that digital video practices centered on human rights, social justice and protest movements require adaptable linkages between supportive structures, creative capacities and digital video technologies in order to produce sustainable and creative digital video practices buttressed by documentary agendas that fuel their dynamic evolution. My research seeks to engage with the complexities of agency and technology and examines their significance in different contexts by providing a constructive outlet for practitioners to share the process behind their methods in order to offer insight into their creative workflow. Digital video technologies are proliferating at a rapid pace, yet very few video practices have formed that suggest linkages to documentary traditions. One can bear witness, yet to traverse video documentation in order to create a rhetorical argument of meaningful witnessing is a complex process that requires more than easy access to mobile video tools connected to the Internet. The case studies analyzed in these three democratic nations support the argument threaded throughout the project; digital video practices have the potential to thrive, albeit in pockets where formal or informal support systems are present and through assemblages where digital video technologies are constantly being adapted and an investment in human capital is paramount to the privileging of digital video tools or online platforms. Case studies that focus on individual practices in New York City and New Zealand reinforce the difficulties practitioners face when attempting to cultivate video practices without supportive structures. Comparatively with other case studies in India and New York, individual practices with long-term organizational support navigate challenges and re-assemble their practices in order to remain sustainable and influential. This study also engages with assemblage theory in the context of documentary history and contemporary digital video practices and reassesses the historic relationship between emerging photographic, film and video tools and the lens based practitioners that harness these apparatuses for documentary purposes. Like assemblings themselves, these creative associations are never smooth at their inception, but require adaptable solutions and adjustable reassemblings in order to maintain the potential for sustainable practices to develop and flourish. This dissertation argues that as digital video practices continue to evolve, they have the potential to redefine creative approaches to documentary media and the opportunity to confront historic traditions of the documentary form.

    View record details
  • Enhancing the Reading Engagement of University English Language Learners: An Action Research Project

    Lee, Jocelyn Yee Vun (2015)

    Doctoral thesis
    University of Waikato

    Despite burgeoning research that has been conducted on the broad term “engagement” in the past decades, research into engagement in English as a Second Language (ESL) or English as a Foreign Language (EFL) contexts remains scarce. Furthermore, in the English Language Learners (ELLs) context in Malaysia, where reading avoidance seems to be an issue, no research has specifically addressed reading engagement. This qualitative case study aims to increase student reading engagement through a strategy-based intervention, Comprehensive Approach to Reading Engagement (CARE), designed to engage ELLs with whom it was conducted under an action research paradigm. Another purpose of the study is to investigate the extent to which reflective practice and development as an action researcher would empower the practitioner in her professional development. Data were collected from 41 students enrolled in an intact university class for 36 hours; a duration of a semester. Six participants, each representing different engagement levels, were selected for close study. Data collected from the six participants in this study were obtained from multiple sources, including transcriptions of participants’ reflective reading logs; transcriptions of audio-recordings of group discussions and a group interview; transcriptions of audio-recordings of the researcher’s private speech during lessons; and the researcher’s reflective journal. Most of the data were qualitative, but some - such as the word count in logs, speech size, number of turns in discussion, and reading engagement scores - were quantitative. In the first phase of the action research cycle, students received explicit instruction and teacher modelling, and in the second phase, they worked more independently. The data were subject to a procedure of grounded analysis, and triangulated to achieve a thick description. The results showed that interactional opportunities such as retelling and group discussion supported four dimensions of ELLs’ reading engagement: behavioural, cognitive, emotional and agentic. From a sociocultural perspective, ELLs need one another to achieve engagement. Peer scaffolding, or collective scaffolding, in ways analogous to teacher scaffolding exemplified students’ agency. The findings of the present investigation showed that sustained silent reading, when effectively scaffolded, tended to have positive effects on ELLs. Evidence in the present study showed that growing engagement appeared to be attributed to Comprehensive Approach to Reading Engagement (CARE), which allowed ELLs to move along the reading pathways from initial engagement, to emergent engagement, and finally, deeper engagement with texts. As a means of examining the practitioner’s position and practice, action research revealed the teaching style and tacit knowledge of the practitioner’s everyday practice. As a reflective teacher, I moved along a continuum comprised of identifying a problem (students were disaffected with reading), developing a research design, collecting data, refining the procedures, analysing the data, and presenting aspects of the study in the public domain. The present case study can be related, rather than generalised, to similar contexts. The study can make an original contribution to an academic understanding of reading engagement and the teacher’s reflective practice in relatable contexts. These findings have important implications for practitioners and researchers; they suggest that neglecting the role of reading engagement could be the cause of missed opportunities to support ELL literacy development and students’ critical thinking stance. The present study also shows that developing reflective opportunities has evident consequences for teachers who are engaging in action research.

    View record details
  • Embodied Cognition and Representation in Domesticated Dogs

    Osto, Kate (2015)

    Doctoral thesis
    University of Waikato

    Embodied cognition is a relatively recent approach in the philosophy of mind. Similarly, the volume of research into dog cognition has increased in the last decade and is set to keep on growing as we learn more about the animals with which we have associated for so long. This thesis argues that the principles of embodied cognition can be productively applied to the study of dogs. Adoption of these principles can improve experimental design and inform the conclusions that we draw from empirical data regarding dogs’ cognitive capacities and behaviour. This dissertation advocates for ethologically appropriate studies, designed for dogs rather than humans, a greater emphasis on the dynamic interplay between the dog, environment and humans, and fresh interpretations of the behaviour and cognitive skills that dogs demonstrate. Moreover, the models of embodied representation expounded in this thesis aid our understanding of dog behaviour and cognition and can enhance our approach to dog training. The thesis closes with a case for embodied representations as facilitators of rational actions in the domesticated dog.

    View record details
  • Part of the problem and part of the solution? Non-state armed groups and humanitarian norms in Burma/Myanmar

    Jagger, Stanley Jeremy (2016)

    Doctoral thesis
    University of Waikato

    Civil wars involving non-state armed groups in Burma have been driven by a complex mix of historical socio-political grievances and economic factors. The central government and its armed forces have conducted counterinsurgency campaigns against myriad rebel groups in ethnic areas virtually since independence in 1948. Civilian populations caught in these conflicts have suffered immensely as a consequence. The government and army have never completely controlled all the territory and people of the internationally recognised state as it exists on the map. Instead, in some areas it has been armed groups and welfare actors associated with them that have been responsible for limited administration and service provision to conflict-affected populations. Despite tolerance or support for this non-state governance in some areas, armed groups still present threats to the security of the constituencies they also claim to represent. This thesis assesses the factors that have facilitated or obstructed armed groups’ actions and the extent of their compliance (or not) in response to the norms against landmine use and the recruitment of children. While studies in other regions on armed groups and humanitarian norms have tended to consider policies of violence deliberately directed against civilians, the present study considers these less deliberate threats that armed groups in Burma present to the security of their own constituencies. It explores a set of theoretical propositions drawn from literature that has addressed armed groups from the perspectives of humanitarian engagement, sociology and political economy analysis of armed conflict. These contrasting approaches offer a more inclusive framework for analysis, considering the social, economic and coercive military and political structures influencing armed groups, affected populations and humanitarian actors engaging with them in relation to these issues. This thesis contends that perceived legitimacy and the role of armed group associated welfare and civil society actors have been significant influences on attempts to ameliorate the impact of these issues. The perspectives and influences of legitimacy diverge, however, between international support for the prohibition of landmine use and underage recruitment, and local perceptions, from armed group constituencies and the government, of the groups as credible armed actors. Localised economic agendas combined with geographical dispersion and weak organisational cohesion have also been factors leading to less compliance with these protection norms. The findings indicate that there is also considerable divergence in the extent of compliance between the two norms. Whereas landmine use remains perceived as militarily necessary to most armed groups in Burma and related to their maintenance of local legitimacy, children involved with armed groups are seen as less vital militarily, and external engagement with armed groups to address this issue has met with more acceptance over time. In the light of bilateral ceasefires and ongoing negotiations since 2012, the willingness and capacity of the armed groups and their welfare wings to address these concerns for conflict-affected populations will be important for their future support and for lasting political settlements.

    View record details
  • Carbon dioxide and methane emissions from the Te Arawa lakes of Rotorua, New Zealand

    Santoso, Arianto Budi (2016)

    Doctoral thesis
    University of Waikato

    One of the biggest issues confronting humankind today is global warming due to the rapidly increasing greenhouse gas (GHG) emissions, namely CO₂, CH₄ and N₂O. The Intergovernmental Panel for Climate Change (IPCC) has prepared an emission reduction strategy. So far, inland waters, including lakes and reservoirs, have not been included in the global carbon cycle. However, the contribution of inland waters to global CO₂ and CH₄ emissions has been identified to be important. Inland waters are also known to be a major sink for GHG emissions by attenuating carbon that would otherwise be transported from the terrestrial landscape to the ocean. Lakes are also very sensitive to climate change as well as to human impacts generally, and these effects will need to be considered in understanding the future role of lakes in the global carbon cycle. This study aimed to improve understanding of CO₂ and CH₄ emissions from lakes, and to quantify these emissions under changing climate and nutrient loading regimes in a regionally discrete group of lakes of volcanic origin in North Island of New Zealand. It included a comprehensive field study of one lake, application of process-based numerical modelling to the lake, and collation and critical analysis of existing datasets for the group of lakes. The primary study site was Okaro, a monomictic eutrophic lake where a major restoration program has been in place for more than one decade. The study also extended to 10 other lakes in order to give insights into effects of different nutrient and mixing regimes on carbon sources and sinks Based on observations over a one-period (September 2013 – October 2014), Lake Okaro accumulated CO₂ and CH₄ in the hypolimnion during summer stratification. These gases were entrained into surface waters as lake started to turnover just prior to complete mixing in winter. As recorded in many other eutrophic lakes, the net CO₂ flux was mostly from the atmosphere to the lake. However, CO₂, together with CH₄, escaped from the lake as a pulsed emission in winter. Using a simple annual mass balance model it was calculated that, ~31% of CH₄ sourced from the sediment escaped to the atmosphere through diffusive flux. The remainder was likely to be oxidized in the water column. The model also showed that on an annual basis the net CO₂ emission is out of the lake. These findings suggest that eutrophic lakes may actually be net emitters of greenhouse gases and that pulsed emissions may be an important contributor to the direction of the flux. This study did not account for CH₄ ebullition, however, and therefore the magnitude of GHG emissions from this lake is likely to be lower than predicted. The effects on CO₂ and CH₄ emissions from Lake Okaro of a warming climate and changes in nutrient loads was simulated using a coupled hydrodynamic-ecological model (GLM-AED2). Future possible changes were simulated by altering model forcing data, increasing air temperature by 2.5 °C. Internal and external nutrient (nitrogen and phosphorus) loads were also either halved or increased by one half. Model simulations showed that annual CO₂ uptake by the lake was enhanced under a warmer climate, but emissions of CH₄ increased during lake overturn as a result of greater diffusive fluxes. Total GHG emissions, as CO₂ equivalent (kg CO₂-eq m⁻² y⁻¹), from the lake were predicted with model simulations to increase by 27% under a warming climate, relative to present conditions. This increase would be reduced to 19% if nutrient loading was halved. A first-order diagenesis model was used to estimate the carbon deposition in the 11 Te Arawa lakes. The most productive lakes, using chlorophyll a as a proxy, had higher rates of carbon deposition in the bottom sediments than the less productive lakes. However, burial efficiency (buried carbon: deposited carbon) was lower in productive lakes meaning that most of the deposited carbon in these lakes is remineralized back into the water column. This remineralization process can be associated with CO₂ and CH₄ emissions from the lake. The results of this study highlight that eutrophic lakes may contribute emit higher levels of GHGs to the atmosphere than has previously been estimated, primarily as a result of pulsed emissions associated with the onset of seasonal mixing, at least in monomictic lakes. Eutrophication and climate warming are likely to enhance GHG emissions from lakes. The findings from this study have important implications for global GHG fluxes and indicate that fluxes into or from lakes need to be included in inventories. Reducing nutrient loads to lakes could offset some of the predicted increases in emissions of GHGs that are likely to occur with climate warming.

    View record details
  • Temporal variability in the water quality of a deep temperate oligotrophic lake

    Kpodonu, Alfred Theodore Nutefe Kwasi (2016)

    Doctoral thesis
    University of Waikato

    Lakes change over time in response to climate and catchment disturbance, even in the absence of anthropogenic stressors. This temporal change may impact the setting of reference conditions for lakes. Many sources of information including monitoring data, historical information, modelling and paleolimnology can be used to understand temporal dynamics of lakes. In this thesis, the contribution of catchment disturbance by volcanic eruptions, introduction and proliferation of invasive mammals, and climate variability, to temporal variability in lake reference conditions was studied in a deep lake (Lake Okataina) in the Central North Island in New Zealand that is close to reference state. The lake and its catchment have been subject to anthropogenic and natural biotic and abiotic disturbances during the last millennium. Polynesian settlements were thought to have been established in and around the lake catchment in the early 14th century following the Kaharoa eruption of AD 1314 ± 12. Mt Tarawera erupted 10 June 1886 and damaged large tracts of vegetation in the Okataina catchment. Following European settlements around the catchment in the early 20th century, mammals which were hitherto not present, were liberated into the forest and rainbow trout (Oncorhynchus mykiss) were released into the lake. Large populations of the dama wallaby (Macropus eugenii), wild boar (Sus scrofa), red deer (Cervus elaphus) and the Australian brushtail possum (Trichosurus vulpecula) exist in the catchment. These mammals have become the “new normal” in many New Zealand catchments. To understand the role of volcanic eruptions and invasive mammals in shifting baseline conditions of lakes, two 49 cm cores were retrieved from a central deep location at Lake Okataina. The core was sliced at 1 cm intervals and slices dated using 210Pb, with the tephra from the Kaharoa and Tarawera eruptions used to validate the dates and benchmark events. Dating indicated the length of the core encompassed the period between the Kaharoa eruption of AD 1314 ± 12 and 2009. Various inorganic and organic geochemical proxies in the sediment core slices were analysed to determine: changes in catchment erosion, phosphorus speciation, phytoplankton community assemblage, primary productivity, sources of organic matter loading, redox potential, and internal phosphorus loading to the lake. A suite of statistical techniques, including structural equation modelling (SEM), general linear modelling (GLM), nonmetric multidimensional scaling (NMDS) and correlation analysis was used to interpret vertical changes in the composition of the core slices and relationships amongst analytes. SEM was used to compare the relative importance of climate and catchment disturbance in changing the primary productivity of Lake Okataina after the Tarawera eruption (1886) and European settlement (1900). Changes in historical primary productivity inferred from total organic carbon in sediment core slices were modelled as a function of geochemical proxies for erosion (Al and Ti) and records of climate variability (Southern Oscillation Index and Temperature Anomaly). The results of this study showed that erosion is the main driver of changes in primary productivity although climate contributes substantially to the variations, and also contributes to changes in erosion itself. The relationship between phosphorus speciation and algal community dynamics in the lake over the past ~ 700 years was established by applying NMDS and GLM to sequentially extracted phosphorus species and algal pigments from the sediment core. Pigments representing diatoms, cyanobacteria, chlorophytes and chryptophytes were measured vertically through the core at 1 cm intervals, as well as phosphorus associated with apatite and CaCO₃, Fe and Mn (oxy) hydroxides, Al (oxy) hydroxides and labile phosphorus. Highly significant correlations were established amongst the algal groups and the phosphorus fractions. The NMDS showed diatoms were strongly correlated with phosphorus fractions associated with permanent burial (apatite and CaCO3 and Al (oxy) hydroxides), while cyanobacteria and chlorophytes were correlated with potentially bioavailable phosphorus (Fe and Mn (oxy) hydroxides and labile phosphorus). Chlorophytes, cyanobacteria and chryptophytes co-dominated when diatom populations were reduced, and vice versa. Using GLM, phosphorus fractions could be used to hindcast historical variations in the composition of algal communities (as inferred from pigments), with the exception of alloxanthin (representative of chryptophytes). Long-term changes in the water quality of Lake Okataina were inferred from sediments deposited from 1836 to 2009, during which time the forested catchment was disturbed by both a pyroclastic volcanic eruption (Tarawera 1886) and invasive mammals (commencing c. 1900). Multiple sediment geochemical proxies were analysed stratigraphically to ascertain trends in organic matter loading (TOC, TN, δ ¹³C and δ ¹⁵N and TOC/TN ratio), primary productivity (Ni, Cu), redox potential (U, V and Mo) and phosphorus retention capacity (Al/Fe and Al/P ratios) of the lake. The chronosequence of the proxies showed that the main source of organic matter loading to the lake is algae although terrestrial loading was increased immediately after the eruption of 1886. Erosion of inorganic materials was relatively high after the eruption but decreased after about twenty years, possibly linked to vegetation regrowth. After 1920 there was a sustained increase in the terrestrial flux of inorganic material. The redox potential of the lake also changed substantially from about 1930, suggesting a reduced degree of bottom water oxygenation. Primary productivity increased considerably after about 1960, while the phosphorus retention capacity of the lake has substantially decreased over the last 50 years. Using eleven years (2003 to 2013) of contemporary monthly monitoring data, I tested for patterns of temporal coherence in three deep oligotrophic lakes of the Rotorua region, which have similar catchment geology, trophic state and morphometry. Variables measured in the upper 1 m and bottom 2 m of the lakes, or variables calculated from depth profiles, as well as water level, were included in the coherence analysis. The directly measured variables included temperature, dissolved oxygen, nutrients and chlorophyll a, and the calculated variables were depths of the thermocline, deep chlorophyll maximum and euphotic zone, as well as Schmidt stability. Temporal coherence was calculated for each of variable using Pearson correlation coefficient values after LOESS decomposition. The average temporal coherence for the lake pairs was high (r=0.65) indicating that the variability in most lake water quality properties is not lake-specific, but instead responds strongly to regional climate. Surface variables were more coherent than those at depth. Physical variables were more coherent than chemical variables, and the variables derived from the depth profiles were less coherent than directly measured variables. Our results indicate the strong influence of regional climate on physical variables in particular, which propagates into progressively reducing influence on chemical and biological variables. The effects of climate are progressively filtered from physical to chemical and biological variables. Coherence analysis is a useful tool to tease apart the relative influence of climate change on these variables and provides a contemporary context for lake behaviour in response to climate forcing, rather than using specific lakes which are benchmarked to a pre-anthropogenic era. The results of this thesis show that while the effect of eruptions is catastrophic, it is also relatively transient compared with the recent impacts of invasive mammals and climate warming, which are more continuous perturbations to the lake and landscape dynamics. Climate variability and invasive mammals tended to act synergistically to increase catchment loads of sediment and nutrients to the lake, effectively creating a shifting reference condition for a lake that would otherwise be considered relatively stable. With current climate change scenarios for New Zealand showing increasing temperatures, and without significant control of exotic mammals, recent trends in phytoplankton assemblages observed in this study, towards domination by cyanobacteria and chlorophytes, may be expected to be reinforced, and bottom-water oxygen levels may decline further. In setting targets for lake restoration goals, management of populations of invasive mammals should be included where there are substantial areas of native forest, because of the potential for these species to reduce vegetative cover, increase loads of sediment and nutrients to lakes, and negatively impact water quality.

    View record details
  • The control of wind and waves on sediment transport asymmetry and the long-term morphological development of estuaries

    Hunt, Stephen (2016)

    Doctoral thesis
    University of Waikato

    Most theories on the equilibrium shape of estuarine basins highlight the dominance of tidal asymmetry in controlling the hydrodynamic and morphodynamic feedbacks that ultimately lead to a stable morphological state. This thesis uses field measurements, numerical modelling and sediment deposition records to investigate how waves interact with tidal processes and how these interactions influence sediment transport and the non-linear feedbacks between hydrodynamics and estuarine basin morphology. Numerical modelling experiments were conducted over a series of idealised estuaries representing different stages of infilling, which show that wind and waves are far more efficient than tides at shaping intertidal areas, with the effect being subtly dependent on the depth distribution in the intertidal. Moreover, the wind and wave climate can substantially alter the hydrodynamic regime over the entire estuary and in intertidal areas can exert a much greater control on asymmetry than tidal currents alone, which dominate in the deeper channels. Under the effect of tides alone, currents over intertidal flats are to found to remain flood-dominant as the estuary infills, thus promoting continued accretion until tidal currents become too weak to entrain sediment. Therefore, estuaries with only tidal currents are likely to evolve into in-filled areas of salt-marsh or mangrove with drainage channels, whereas fetch-aligned estuaries (in which wind-waves are common) have a greater probability of attaining deeper hydrodynamically-maintained stable intertidal areas. Although waves have little direct influence on hydrodynamics within the subtidal channel, the tidal asymmetry is controlled by the height and volume of the intertidal areas and therefore is indirectly influenced by wave activity. The higher-energy, infrequent storm-wave events can considerably modify estuarine morphology over short timescales whereas lower-energy but perpetual effects like the tides operate continuously and so the relative contribution of such events in shaping the long-term morphological evolution can be considered on a range of timescales. Within this thesis a combination of hydrodynamic measurements, sediment deposition records and numerical modelling are used to determine the conditions under which observed waves are morphologically significant. Morphological significance is defined as when waves influence tidal and suspended sediment flux asymmetry and subsequently infilling over geomorphological timescales. By comparing a fetch-aligned and a non fetch-aligned mesotidal basin, it is shown that for a sufficiently large fetch, even small and frequently occurring wind events are able to create waves that are morphologically significant. Conversely, in basins with a reduced fetch, wave events are less frequent and therefore of far less morphological significance. The role of tidal range in controlling sediment transport is investigated through consideration of its influence on bed shear stress, τmax. The decrease in bed shear stress associated with greater water depths is compared to increases owing to the larger fetch that accompanies the increased tidal range and the generally stronger currents associated with larger tidal range. Here, it is shown that during neap tides the reduction in water depths around high water and tidal currents are not offset by the reduction in fetch. Thus, it is shown that the basin-averaged τmax is similar during both spring and neap tides in addition to the shorter duration of slack water during neap tides. Consequently, as τmax is lower in the subtidal channel during neaps, the sediment gradient (and hence sediment transport potential) between tidal flats and channels is greater. Thus it is concluded that sediment deposition potential may actually be increased during a neap tide. This result is in sharp contrast to previous observations from microtidal wave-dominated environments, in which differences between spring and neap result in increased erosion during spring tides. Overall, this thesis shows that short period locally generated waves can be considered a morphologically significant hydrodynamic process within estuaries. With increased fetch, waves become more morphologically significant relative to tides as even low, frequent wind speeds are able to generate waves that are capable of controlling patterns of sediment transport.

    View record details
  • Exploring teacher transition in New Zealand primary schools: The impact of changing class levels on teacher professional learning

    Carlyon, Tracey (2016)

    Doctoral thesis
    University of Waikato

    This thesis provides an in-depth understanding of teacher transition and the impact of this on teacher professional learning. The focus is on the transition that occurs when a teacher changes from teaching in one class level to another in New Zealand primary schools. Of particular interest is learning more about how teachers’ perceptions of transition are developed, the outcomes that are generated for them and other stakeholders, how teachers negotiate transition, and the role of school leadership in teacher transition. This research uses case study methodology, and although it is primarily qualitative in nature, a mixed methods approach was applied to gather both qualitative and quantitative data. Data were collected from 536 teachers via an online survey and from four teachers by means of a semi-structured interview. By converging and comparing broad numeric trends that emerged from the quantitative data with the detail from the qualitative data, I was able to gain a more in-depth understanding of teacher transition and the impact of this on teacher professional learning. Findings from this study suggest that there are significant benefits for teachers and other stakeholders when teachers transition. These highlight that transition has a very significant impact on teacher learning, and stimulates the interplay between a teacher’s professional learning and professional identity which can result in changes in practice and pedagogy. The influence from these changes is shown to strengthen a teacher’s professional identity, bring about more effective teaching and extended professionality. Those theories which suggest that teacher development occurs in sequential stages and that all teachers progress through these stages in a linear fashion as they become more experienced, are challenged, and the suggestion that teachers require opportunities, such as transition at different times during their careers for professional development and learning, is supported. There are four major implications for teacher education that have emerged from the findings of this study. First, they suggest that cognisance be taken of the opportunity that transition provides for teacher learning and that transition is conceptualised as a form of professional learning and development. Secondly, they indicate that when tensions are acknowledged and clearly understood, teachers are better placed to see transition as a positive opportunity for professional learning and development. The third set of implications concern teachers being given sufficient opportunities to prepare, both mentally and physically, for transition. Finally, the study shows that the success of teacher transition is fundamentally dependent on the action of school leadership to ensure that school cultures and systems are conducive for teachers to change class levels successfully. The new information from this study gives support to initial teacher educators, student teachers, teachers, school leaders, schools, Boards of Trustees and policy makers to ensure all teachers can successfully transition. In an effort to build knowledge about teacher transition, this study advocates that all teachers are given the chance to take full advantage of the unique opportunity for rich professional learning and development that transition between class levels offers.

    View record details