Higher Degree Theses

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Now showing 1 - 20 of 2189

Regulating online hate speech and harmful content in Aotearoa New Zealand - beyond criminalisation and towards a statutory duty of care
(The University of Waikato, 2025-12) Tan, Rachel Sue Yin; Alvarez-Jimenez, Alberto; Barton, Barry; Dizon, Michael
This thesis examines how New Zealand regulates online hate speech and harmful content, and evaluates whether current law provides effective protection in the digital environment. The study considers how social-media platforms shape the spread of harmful expression and assesses whether New Zealand’s existing legal framework is equipped to respond to these risks while maintaining the right to freedom of expression. The central question guiding the research is whether the present approach is adequate, and what reforms may be needed to address harm more effectively. The thesis adopts an interpretivist and qualitative methodology, drawing on doctrinal, socio-legal, comparative, and political-legal methods. It uses behavioural, regulatory, and normative theories, including the Online Disinhibition Effect, modalities of regulation, and dignity- and equality-based approaches to free expression. These perspectives help explain why harmful content escalates so quickly online and why traditional legal tools struggle to respond. The analysis proceeds in three stages. First, it examines the operation of digital platforms, focusing on algorithmic amplification, design choices, and the limits of automated moderation. Second, it reviews New Zealand’s legal framework, including the Harmful Digital Communications Act 2015, the Human Rights Act 1993, and the New Zealand Bill of Rights Act 1990. This review shows that the current system is reactive, fragmented, and heavily dependent on voluntary platform policies. Third, the thesis draws comparative insights from the United Kingdom, Australia, France, Germany, and the European Union, where more proactive models, particularly statutory duties of care and transparency obligations, have begun to address platform-level risks. The research concludes that New Zealand’s present approach does not adequately respond to systemic and group-based harms. It argues that a statutory duty of care, supported by risk-assessment requirements, algorithmic transparency, and proportionate safeguards for freedom of expression, offers a more effective and balanced framework. The thesis contributes to existing scholarship by integrating behavioural and regulatory theory with comparative legal analysis and by proposing a model of platform accountability tailored to Aotearoa New Zealand’s legal context and human rights commitments.
Analysing and scoring cybersecurity vulnerability reports using deep learning
(The University of Waikato, 2026) Zhang, Zijing; Pfahringer, Bernhard; Kumar, Vimal; Mayo, Michael; Bifet, Albert
Vulnerability analysis plays a crucial role in cybersecurity, as it helps identify and mitigate potential threats to systems and networks. It is essential for organizations to understand the severity of vulnerabilities and prioritize their remediation efforts. This thesis focuses on the analysis and scoring of cybersecurity vulnerability reports using deep learning techniques. By leveraging large language models and machine learning algorithms, this thesis aims to improve the accuracy and efficiency of vulnerability classification and severity assessment. The research presented in this thesis includes the development of models to estimate the CVSS of vulnerabilities based on their descriptions, comparing the performance of AI models with human experts. For CVSS 3.1 severity level prediction task, the USE model achieves an accuracy of 0.73. The USE model outperforms human experts with a macro mean squared error of 0.128, which is four times lower than that of human experts (0.537). Meanwhile, quality of vulnerability descriptions is also analyzed to understand its impact on the performance of machine learning models. A BERT-based model (‘DesQ’) is proposed to assess the quality of vulnerability descriptions, achieving an accuracy of 0.76. A dataset of vulnerability descriptions with quality labels is curated and analyzed to understand the distribution of description quality across different vendors and reporting agencies. The analyzer BART model (‘EVAL’) identifies missing essential vulnerability aspects. Trained on a specialized quality dataset of 450 manually labeled entries, EVAL identifies Vulnerability Impact as the most frequently missing component across analyzed weaknesses. This thesis also explores the use of explainable AI techniques to provide insights into the decision-making process of machine learning models, enhancing their interpretability and trustworthiness in mapping root causes to vulnerabilities.
Structural and thermal performance of cold-formed steel studs with slits
(The University of Waikato, 2025) Ghosh, Kushal; Roy, Krishanu; Lim, James Boon Piang; Carson, James K.; Hudd, Ray
Cold-formed steel (CFS) studs in lightweight construction increasingly incorporate web slits to limit thermal bridging, yet these openings can reduce axial strength. This thesis integrates structural and thermal assessments through validated non-linear elasto-plastic finite element analysis (FEA) and complementary heat-transfer modelling. Shell-element FEA models were developed and validated against tests, then used in a 960-case parametric study spanning section dimensions, slit geometry, thickness, and member length to establish the influence of slits on concentric axial capacity. The results were evaluated against the Direct Strength Method (DSM) in AS/NZS 4600, leading to strength-reduction recommendations and modified DSM expressions that achieve reliability indices β ≥ 2.5. The programme was extended to combined axial compression and minor-axis bending using 1,134 FEA models with six eccentricities, demonstrating a systematic discrepancy in current AS/NZS 4600 interaction checks: strengths are generally underestimated at eccentricities of 10–25 mm and overestimated at 50 mm. A new interaction equation incorporating element and web slenderness ratios is proposed and verified within the AISI S100 reliability framework. Subsequently, a parametric three-dimensional heat-transfer study quantified the dependence of heat flux on geometry and slit parameters, providing a quantitative basis for thermal performance gains and their balance with strength. The thesis proposes design recommendations and revised equations for slitted CFS studs that satisfy codified reliability targets and support informed selection of slit configurations to balance energy efficiency and structural capacity in practice.
Strengthening of cold-formed steel channels using different reinforcing options and innovative connections
(The University of Waikato, 2026-03-18) Wang, Wei; Roy, Krishanu; Lim, James B.P; Fang, Arthur
Cold-formed steel (CFS) has become an essential material in modern construction due to its lightweight, cost-effectiveness, and versatility. This study primarily investigated the web crippling capacity of channels with elongated edge-stiffened web holes. Compared to traditional circular edge-stiffened web holes, these elongated holes accommodate larger electrical conduits and water supply systems. The new Direct Strength Method (DSM) was developed to accurately predict their web crippling strength. In addition, this research explored key advancements in CFS systems, including built-up box sections and trusses equipped with advanced Howick Rivet Connectors (HRCs). These high-performance connectors have demonstrated superior performance, providing greater connection strength than traditional self-drilling screws and better ductility than bolted connections. In this study, HRCs were utilized in truss systems and built-up box sections, offering critical data to support their practical application in engineering projects. Furthermore, axial tests on telescopic studs and swaged sections were conducted to address installation challenges commonly encountered in real-world scenarios. Through experimental studies, numerical simulations, and parametric analyses, this research enhances the understanding of these systems, paving the way for more reliable and efficient applications in structural engineering. The findings are synthesized to highlight their implications and provide recommendations for integrating these insights into international design standards. By bridging critical knowledge gaps, this thesis contributes to the broader adoption of advanced CFS systems in construction, fostering innovation, sustainability, and efficiency in structural design.
The impact of remittances on the monetary transmission mechanism in low-income countries
(The University of Waikato, 2026) Abdul Raheem, Jahan; Holmes, Mark J.; Ryan, Michael; Hassan, Gazi M.
This thesis consists of three studies investigating the impact of remittances on monetary transmission mechanisms. The prime objective of this research is to explore how the inflow of remittances affects the different monetary transmission channels in remittance-receiving economies and what other factors influence remittances in altering their effects on monetary transmission mechanisms. The first two studies were undertaken using a panel of 51 remittance-receiving countries, while the third study used Sri Lanka as the location. The first study investigates the effects of remittances on bank credit and exchange rate channels, using a panel Structural Vector Autoregression (SVAR) to investigate how remittances affect these intermediate monetary transmission channels. The estimated impulse responses (IRs) of bank credit and exchange rates to a shock in remittances show a significant variation between countries in responding to a shock in remittances. In the second stage, we regress the IRs of selected horizons on selected economically significant variables to find out what other factors contribute to this variation. The cross-sectional regression suggests that the magnitude of remittances in terms of the remittances-to-GDP ratio affects the exchange rates channel significantly. However, the effect of remittances on bank credit is determined by the level of remittance inflow and the savings-to-GDP ratio. More precisely, remittances significantly affect the bank credit channel in countries where the remittances-to-GDP ratio is higher than five percent of GDP. The overall findings of this study suggest that policymakers, especially in higher remittance-receiving countries, have to pay attention to the role remittances play in weakening the monetary transmission mechanism (MTM). The second study investigates how institutions play a role in altering the effects of remittances on the bank credit channel. There are arguments about whether remittances contribute to the expansion of credit in remittance-receiving countries. In this study, we use a panel SVAR model to estimate the IRs of bank credit to a shock in remittances and regress these IRs on a set of institutional and other economically significant variables. The regression results indicate that stronger corruption control and regulatory quality, along with savings-to-GDP and remittances-to-GDP ratios, are associated with credit expansion in response to remittances. This empirical finding indicates that monetary policy measures may have difficulty in achieving their objectives through bank credit in higher remittance-receiving countries, which have a strong corruption control and regulatory quality environment. The third study analyses how the effects of remittances vary with regard to bank credit, exchange rates, and asset price channels in the conflict and post-conflict periods in the Sri Lankan economy. We apply a country-specific SVAR model by using the monthly data from 1996 to 2019. The empirical analysis suggests that remittances significantly affect these monetary transmission channels in the post-conflict period, and their effects on bank credit and asset prices are relatively stronger than the exchange rate channel in this period.
Ka hao te rangatahi: Exploring school and work pathways for rangatahi Māori / Youth growing up within gang space in Aotearoa
(The University of Waikato, 2025) Maihi, Bonnie; Tiakiwai, Sarah-Jane; Whaanga, Hēmi
This thesis explores the experiences of rangatahi Māori growing up in gang environments in Aotearoa, focusing on their educational and employment journeys. The research aims to elevate the rangatahi narratives without reducing them to mere statistics or stereotypes, highlighting their resilience and insights in contexts often characterized by stigma and judgement. Employing principles of Kaupapa Māori, Critical Pedagogy, and a Waka navigation framework, this study challenges deficit-based perspectives that typically dominate discussions about gangs. On a practical level, it advocates for trust-based partnerships with gang whānau, emphasizing the importance of honesty and respect to foster collaboration. Existing Whānau -led initiatives illustrate the possibilities of merging cultural knowledge with everyday survival, showcasing resilience as a lived reality. Theoretically, the research offers an insider perspective, positioning myself as researcher to honor lived experiences and mitigate traditional negative framings of gang spaces, instead framing them as complex sites of identity and resilience. Ultimately, this thesis posits that rangatahi Māori in gang settings are not merely problems to be solved but are agents of hope and strength, rooted in their heritage. Their futures should be shaped by their identities rather than deficits, affirming their tino rangatiratanga and capacities for meaningful contributions within their communities.
Investigation on fabrication, interface formation, and properties of hot-processed titanium-doped copper/diamond composites
(The University of Waikato, 2025) Ma, Jingnan; Torrens, Rob; Yang, Fei; Bolzoni, Leandro
Efficient thermal management is crucial for next-generation high-power electronic devices, driving the need for high-performance heat sink materials. Copper/diamond composites have emerged as promising candidates due to their exceptional thermal conductivity (TC) and tailorable coefficient of thermal expansion (CTE). However, their performance is limited by weak interfacial bonding, caused by the poor chemical affinity between copper and diamond and severe phonon scattering due to mismatched lattice vibrations. To address these challenges, interface engineering strategies such as pre-coating diamond particles or pre-alloying the copper matrix with carbide-forming elements (e.g., Ti, W, Zr, Cr, B) have been extensively explored. Among these, titanium has shown promise through the formation of a stable titanium carbide (TiC) layer, which significantly enhances interfacial bonding and composite performance. This thesis investigates the thermophysical and mechanical performance of titanium-doped copper/diamond composites fabricated via hot-processing techniques, hot-forging and hot-pressing, with focuses on optimizing fabrication parameters, elucidating interface formation mechanisms, and establishing the relationship between the interfacial microstructure and composites performance. Ti-coated diamond/Cu composites were successfully fabricated via hot-forging, and the effects of forging temperature, diamond volume fraction, and deformation degree were systematically evaluated. The study highlights the crucial role of hot-forging temperature in optimizing TiC interface formation and enhancing interfacial bonding. 800°C is the optimal hot forging temperature to facilitate the dynamic formation of TiC interface layer and ensure a high interface coverage rate on the diamond particles. Additionally, the volume fraction of diamond affects the interface microstructure and TC of the hot-forged composites by affecting the heating behaviour of the composites during induction heating. The relatively large deformation degree can effectively contribute to the densification and interfacial bonding of the composites. 800 °C hot-forged composite with 45 vol% diamond and 80% deformation degree exhibited excellent TC of 529 W/mK, along with a high tensile strength of 241 MPa, attributed to the synergy of uniform distribution of diamond in the matrix, a rough interface, and strong interfacial bonding between the copper and the diamond. The fabrication of copper/diamond composites via hot-pressing, was further investigated employing two interfacial engineering strategies: titanium carbide formation through diamond surface metallization and copper matrix alloying with titanium additives. The results show that diamond metallization shows a better effectiveness in enhancing both mechanical and thermophysical performance than matrix alloying. Notably, Cu/50 vol% Ti-coated diamond composite fabricated at 540 MPa achieved an exceptional TC of 565 W/mK and a tensile strength of about 147 MPa. For the copper-Ti/diamond composite containing 0.5 wt% Ti processed at 1050 °C, it exhibited a comparable TC (554 W/mK), but a relatively low tensile strength (93 MPa). The optimal processing pressures for maximizing TC and mechanical strength in hot-pressed Cu/Ti-coated diamond composites differ due to interface microstructure: continuous interface enhances mechanical strength through strong interfacial bonding, whereas jagged interface arranged in parallel on the diamond surface minimizes interfacial thermal resistance. A comparative study between the two processing routes revealed that hot-forging outperforms hot-pressing at high diamond content (55 vol%) due to greater matrix deformation and more uniform diamond distribution, whereas hot-pressing becomes advantageous at lower diamond fractions (45-50 vol%), where applied pressure provides effective densification and interfacial microstructure becomes the dominant factor governing composite performance. A detailed investigation into interface formation mechanisms was conducted on 540 MPa hot-pressed composites with 50 vol% Ti-coated diamond. The results revealed that the distinct atomic configuration of individual diamond facets govern the nucleation and growth behaviour of TiC at the interface, giving rise to different interfacial microstructures: a continuous Cu/TiC/diamond structure on diamond-{100} facets, and a multilayered Cu/Cu (Ti)/TiC/diamond structure on diamond-{111} facets. Beyond the formation of TiC interlayer on both facets, the semi-coherent orientation relationships (ORs) were identified between TiC and both diamond-{111} facet and copper: (11 ̅1 ̅) TiC // (11 ̅1 ̅) Diamond and [1 ̅1 ̅0] TiC // [1 ̅1 ̅0] Diamond, (111) TiC// (1 ̅11) Cu, [01 ̅1] TiC// [211] Cu. These ensure a high degree of atomic ordering at the interface, enhancing phonon transmission across the interface. Concurrently, Cu segregation at TiC grain boundaries refines grains and strengthens interfacial bonding, further reducing thermal resistance. Furthermore, sub-stoichiometric TiCx present on both facets introduces a mixed metallic-covalent bonding character, facilitating electron-mediated heat transport and promoting nanotwin formation, which migrates phonon scattering by enhancing dislocation mobility. Overall, this work demonstrates that the thermophysical and mechanical performance of copper/diamond composite is governed by the synergistic interplay between processing parameters and interfacial microstructure. The facet-dependent atomic configuration of diamond surface dictate distinct interfacial microstructures, while processing parameters such as temperature and pressure provide effective levers for controlling TiC stoichiometry, interlayer continuity, and interfacial bonding strength. Together, these factors determine the balance between thermal transport efficiency and mechanical strength, establishing a rational framework for interface engineering in high-performance Cu/diamond composites.
Studies on the conservation of waterlogged wood in New Zealand
(The University of Waikato, 1985) Wallace, Roderick Thomas; Mackay, K.
This thesis is a study of properties of certain New Zealand woods recovered from waterlogged environments. The woods are those which were commonly used by the pre-european Maori to make artefacts, and the properties are those which affect the way these artefacts can be conserved after they have been removed from wet archaeological sites. The properties studied were (a) the species of wood used (b) the forms and shapes of the timbers (c) the densities (d) directional shrinkages, and (e) directional penetrabilities of each wood. The results of this research are intended to aid conservators to correctly treat the artefacts. The research began with studies of (a) New Zealand wet site archaeology, (b) the structure and properties of wood in general, and (c) the techniques used to conserve waterlogged wood worldwide. This was followed by a survey of circa. 1000 wooden Maori artefacts from Museums involving the identification, by thin section microscopy, of wood species. 30 wood types from 22 tree species were found to have been widely used. A collection was made of samples of each type in different states of decay. Each sample was tested for density, directional shrinkage and directional penetrability. The penetrability was measured by vacuum impregnation of water into wood blocks. Results were compared to those from sound oak (Quercus robur), a wood which has been studied intensively by conservators in Europe. Detailed summaries of the conservation properties of 26 wood types are given. This reveals that while some New Zealand woods are easy to conserve others provide considerable problems. The latter woods are all highly durable in wet sites, extremely dense, have high shrinkages and are highly impenetrable. These will require special types of treatment to avoid damage during conservation.
The transition to parenthood in New Zealand and a developmental conceptual framework for the study of family change
(The University of Waikato, 1985) Swain, David; Bettison, David; Pool, Ian
The research and reflection reported in this thesis was initially centred on parenthood as ‘crisis’ or ‘transition’. A prospective longitudinal survey of a representative or ‘normal’ cohort of 241 primiparae in Hamilton, New Zealand, was carried out. Data were collected by means of four structured interviews (two antenatal and two post-partum) based on largely pre-coded questionnaires. The Hobbs Checklist (Hobbs, 1965; 1968) was used to measure ‘crisis’. It was found that this New Zealand sample did not experience crisis at or around the birth of their first child. The originally-planned data analysis was a multivariate search for statistical predictors of ‘crisis’, together with an examination of the short- and medium-term consequences of that ‘crisis’. As a result of the finding of no crisis attention was refocussed on more conceptual, theoretical and epistemological issues. A conceptual framework or ‘model’ for handling developmental changes in families was devised. This framework brings together a variety of concepts and ideas from ‘the literature’ together with some original concepts and ideas developed in the course of this project. The conceptual framework is organised around four main dimensions of structure, interaction, transactions and norms. Attention is focussed on the transitions which families may be understood to make between family career categories, especially from ‘couple’ to ‘childbearing’ categories. Ideas of homeostasis, morphogenesis and conflict are integrated into the conceptual framework. The original dataset was then used to investigate the conceptual framework, and areas for both further conceptualisation and further empirical investigation were identified. Some issues remaining from the earlier substantive literature were further considered. In particular, the question of whether a ‘crisis group’ is better understood as the researcher’s construct or a ‘real’ social grouping was considered. It was found to be the former. It is concluded that theoretical orientations and approaches to conceptualisation, as well as a concern with practical issues (social problems, parent education, social work etc.), have strongly influenced research on parenthood in the past towards a focus on ‘crisis’. It is argued that a more comprehensive conceptual framework for the study of developmental change in families is needed. A first draft of such a framework is offered, and the need for further conceptual, theoretical and empirical work is emphasised.
Cellulases from extremely thermophilic anaerobic bacteria: a comparison of several new cellulolytic isolates and the partial purification and characterisation of components of the cellulase complex from one isolate
(The University of Waikato, 1985) Sharrock, Keith R.; Daniel, Roy M.
Forty-seven thermal pool sites in the central volcanic plateau of the North Island of New Zealand were sampled and enrichment cultures on crystalline cellulose screened for growth and cellulase activity. Eight anaerobic cellulolytic cultures resulted. Cellulolytic isolates were obtained from five of these cultures. All were obligate anaerobic non-sporing rods, staining Gram-negative. Most grew well at 75°C but none grew at 80°C. CMCase activity from some isolates exhibited exceptional thermal stability, with half-lives at 85°C in excess of 10 hours. Isolates from two sources, designated TP8 and TP10, were capable of completely hydrolysing crystalline cellulose and accumulated reducing sugar and avicelase activity in the growth medium. Levels of CMCase and avicelase in our most active culture supernatants were between 10 and 35% of those of Clostridium thermocellum grown on the same medium (but at 60°C). All produced acetic acid and ethanol in varying proportions, with a consequent tendency to decrease the pH of the growth medium. Cellobiose at 0.2%(w/v) repressed production of CMCase activity by most of the isolates by about 50%, but led to a slightly increased CMCase production by two of them. One of the isolates capable of completely hydrolysing crystalline cellulose (TP8.T6.3.3.1) was subjected to repeated subculture, reselection and reisolation to ensure its purity. The cell-free cellulase complex of this organism was found to produce partial solubilisation of a range of natural cellulosics, and also contained β-glucosidase activity. Ammonium sulphate precipation and adsorption onto crystalline cellulose were the best of the methods tested for concentrating the low levels of cellulolytic activity in the culture supernatant of TP8.T6.3.3.1. Adsorption onto cellulose was the cheapest alternative and also doubled as a preliminary fractionation and purification step. Three fractions, separated on the basis of their affinities for crystalline cellulose, were found to interact synergistically in hydrolysing crystalline cellulose when recombined. Conventional ion exchange and gel permeation column chromatography served only to subdivide the TP8.T6.3.3.1 cellulase complex into subcomplexes. These were fractionated further using preparative SDS-PAGE and IEF. The cellulose-binding component of the cellulase complex was found to contain an unexpectedly large number of active components (20 being a conservative estimate). Several of these component proteins exhibited clear differences in relative reactivities towards a range of cellulosic substrates. When rerun on SDS-PAGE, almost all produced single protein bands with mobilities indicative of molecular weights covering the range 20,000 to 140,000. Isoelectric points were all in the range pH 4.5-5.0. However, narrow range isoelectric focussing (pH 4.5-5.0) produced further subdivision of these single bands. The bands produced by isoelectric focussing (7-10 per SDS-PAGE band) each bore a share of the endoglucanase activity. We were unable to individually characterize the component activities at this level, and it was not clear whether these multiple components were artefacts of the isoelectric focussing, distinct products of multiple genes, modified products of a relatively small number of genes or microheterogeneity due to ageing of the proteins.
Investigations on the taxonomy and the genetics of caldoactive bacteria
(The University of Waikato, 1985) Martin, Andrea Muriel; Morgan, Hugh W.
The technique of pyrolysis mass spectrometry was used to attempt to obtain taxonomic groupings for a number of extremely thermophilic bacteria isolated from New Zealand hot springs. The New Zealand isolates were compared with a number of appropriate reference strains obtained from culture collections or as gifts from other laboratories. Three groups of bacteria were analysed. The Thermus-like group was found to consist of three species - level groupings with most of the New Zealand isolates belonging to a single species group. The two reference species T. aquaticus and T. thermophilus apparently belong to separate species groups. Bacillus-like strains grown at neutral pH formed three separate species groups which could correspond to the three species of thermophilic Bacilli proposed by Wolf and Sharp (1981). Analysis of a number of archaebacteria confirmed the unique nature of AN1 isolated from a New Zealand hot spring by Morgan and Daniels (1982). The Thermoproteus-type strains isolated from New Zealand seem rather different from the type strain T. tenax which also has some different physiological properties. An interesting feature of these strains was the contribution of sulphur to the mass spectra. Taxonomic groupings did not show a close relationship with source temperature and pH but regional groupings were obtained in some cases. The distribution of AN1-like strains seems to be related to the Na⁺ content of source pools. The majority of New Zealand isolates tended to form rather large clusters, probably at the species level, although sub-species level clusters existed within these. This suggests that although extreme thermophiles may be very variable as reported, this variability is limited. Differences in clustering patterns of different isolates from the same source confirm a considerable level of sub-species level variability does exist. A method for cloning Themrus genes by cosmid packaging was attempted and was apparently successful but gene expression was not demonstrated. A UV inducible temperate phage was isolated from Sulfolobus acidocaldarius strain B-12. It was purified and partially characterised and a method of growing Sulfolobus on solid medium obtained.
Secondary school subject choice: an ethnographic study
(The University of Waikato, 1985) Darnell, Doreen Anne; Haigh, Nigel John
This study of subject choice followed two groups of pupils through the decision-making process at two state, co-educational high schools in the North Island of New Zealand. The high schools were similar in size, location, ethnic composition and range of home background of pupils, but had differing option systems. At the end of their form two year, 53 children (27 boys, 26 girls) were interviewed at their respective primary or intermediate schools while they were considering the options offered to them in form three at one of the two high schools. The children were re-interviewed the following year at their respective high schools. A further 37 pupils (17 boys, 20 girls) were interviewed in form four at their respective high schools while they were choosing fifth form subjects and were re-interviewed the following year after they had experienced the subjects they had chosen. All children in the study were chosen by their teachers as being representative of the range of pupils at their schools, in terms of ability, ethnic origin and home background. In addition, parents of eight of the younger children were interviewed in their homes and 31 teachers, representing all the subjects offered to the children at the two high schools, were interviewed at their respective schools. Analysis of interview transcripts showed that pupils’ decisions were influenced by the structure of the option systems, the attitudes of parents and peers and by the overt and covert actions of teachers. Access to information was found to be a key component of decision making. Children’s and parents’ views about the school subjects showed a strong measure of agreement, but there was less agreement between children’ views and teachers’ views. A model of decision making was elicited from the data and case studies illustrated the range of pupils’ individual experience, in particular, the experience of Maori pupils identified as ‘winners’ and ‘losers’ in the school system.
Why have children: a study of method and meaning in value-of-children research
(The University of Waikato, 1984) Cameron, Jan; Pool, Ian; Bettison, David
The ‘Value of Children’ has been proposed, inter alia, as an important intervening variable in fertility behaviour, and as an explanatory factor in demographic transition. It has been investigated as such by sociologists, psychologists and microeconomists. This thesis is concerned with the notion of ‘value’ which is implied by these investigators. The research addresses three questions: 1. What is ‘Value’? 2. Is the understanding of ‘value’ which a researcher has of the same order as the understanding which a subject has? 3. If not, how might meanings which the subject imputes to ‘value’ of children be understood? Answers to these questions have been sought in several different ways. Firstly, research is seen as a social construction which has its own set of meanings and understandings. This includes prior ideas and modes of analysis: the conceptualisation of ‘value’ is thus understood within the context of sociological, psychological and economic ideas about fertility determination and the nature of social action. The nature of meaning is also explored within a distinctly sociological context whereby imputation of subjects’ meanings is seen to reflect assumptions about objective and subjective meanings, and positivist versus interpretive modes of analysis. Thirdly, the notion of a paradigm is employed to elucidate how subjects, as well as researchers, make sense of their fertility behaviour. These three approaches emphasize that ‘value’ as understood by everyday people does not have the same meaning as that imputed by researchers who have investigated this as an attribute of children. The empirical component of the thesis represents an attempt to apply two different modes of analysis to an elaboration of child ‘value’. Survey data (n=154 pakeha New Zealanders) are compared with material derived from indepth, informal discussions with 15 of the survey participants. Whereas survey data provided some indication of generalities, the conversational analysis was employed to try and gain access to subjects’ understandings of children and having children. These meanings have been deduced by analysis which sought not only the form and content of people’s talk, but which also looked for particular expressions of order, ambivalence and tension, marginality and deviance. Everyday talk was not taken literally, but was taken seriously. The meanings people attributed to children were categorized (by the researcher) as understandings to do with family, immortality and continuity, parenthood, childlessness, economics and biology. Of these, the most pervasive and coherent paradigm whereby subjects understood and gave meaning to children and having children was one labelled a ‘biological paradigm’. This paradigm is not of the same order as that which might be employed by a (‘scientific’) biologist. Rather, it reflects a kind of sense-making which implies an underlying assumption of ‘natural’ order to the course of human events. This exploratory investigation led to a review of the approaches useful to an interpretive analysis of the value of children. A proposal is offered which assumes that meaning is socially constructed in everyday action and interaction with and about children; that talk is a form of action and though metaphorical, reflects the formation, nature and communication of meanings; and that the nature of everyday understanding might be elucidated by examining what is taken for granted and what is questioned, by notions of order and contradictions to that order. By treating meaning as subjective and expressed in parents’ speech of the everyday world, in their common sense, an opportunity is provided to understand more clearly the social meaning which they impute to the idea which previous researchers have labelled the ‘value of children’.
The economics concepts of sixth and seventh form secondary school students and their teachers
(The University of Waikato, 1985) Orere-Clifford, Samuel D.; Freyberg, Peter; Haigh, Neil; Katterns, Robert
The nature of teaching and learning continues to elude educators and researchers despite over half a century of research in teaching and learning. The central problem seems to be how teachers should practise their profession to facilitate student learning. In this regard, there has been several suggestions such as developing certain teacher personality attributes (Ryans, 1960), special teaching behavioural techniques (Rosenshine, 1976a) and the child-centered education of Piaget (1966) and Ausubel (1968). More recently, studies such as the Learning in Science Project of the University of Waikato (e.g., Osborne, 1981a) have drawn attention to the suggestion that children tend to develop misconceptions about scientific phenomena in the classroom. It is felt this could be due to teachers not tapping and relating new material to children’s previous knowledge and cognitive structures. This study sought to examine the suggestions of the Learning in Science Project as described above with regards to Economics. The investigation was therefore aimed at uncovering the Economics ideas Sixth and Seventh Formers generated about certain Economics concepts after lessons. It also investigated the nature of conceptions held by their teachers for the same concepts. The method of investigation included both qualitative and quantitative features. A qualitative approach was used to uncover the ideas held by a small sample of students. This was then reduced into a survey format and administered to a large sample of students and teachers. The findings of the study suggest that Sixth and Seventh Form Economics Students possess conceptions of Economics not generally acceptable to Economists. This substantiates the suggestion of the Learning in Science Project that learners tend to develop misconceptions about phenomena introduced in the classroom. However, the findings of the study also indicate that the teachers of the students also possess misconceptions about Economics concepts. The suggestion is therefore made that students’ misconceptions about Economics concepts may not necessarily be due to teachers not taking students’ past knowledge into account, but to the possibility that teachers may be introducing misconceptions about Economics concepts in the classroom. The study, therefore, suggests that teaching and learning may be enhanced if teachers take stock of the state of their knowledge of subject matter constantly and also introduce concepts to students in such a way as to retain the meanings of experts.
The phytoplankton communities of nine lakes, Waikato, New Zealand: a comparative study of floristics, seasonal dynamics and the influence of herbivory
(The University of Waikato, 1987) Etheredge, Margaret Kay; Chapman, M. Ann; Green, J.D.
The structure and seasonal dynamics of the phytoplankton communities of nine shallow lakes located in relatively close proximity to one another within the Waikato Basin, and of similar age and origin, were studied for one year (July 1983 to July 1984); the lakes were Kainui, Mangahia, Mangakaware, Maratoto, Ngaroto, Rotokauri, Rotomanuka North and South, and Rotoroa. There was a broad range of physico-chemical regimes, a direct result of differing morphometries and quantities of allochthonous dissolved humic material from adjacent peatland and/or swamps, and varying degrees of exposure to wind. Community structure was markedly influenced by humic content, in terms of both α diversity and distribution of species within the major classes, with total numbers of species found per lake ranging from 113 to 210. Temporal patterns of community composition were directly related to specific mixing regimes and morphometry. Lakes which had minimal thermal stability throughout summer were dominated throughout the entire year by one or two algal classes, and it was shown statistically that the major phytoplankters were large, K- selected species (e.g., Botryococcus braunii and Microcystis aeruginosa). Unpredictable sequences of domination, one class replacing another after brief periods of importance, were recorded in lakes where ephemeral periods of summer stratification alternated with either equally short periods of holomixis or weakly developed stratification; the dominant species in these lakes were r- strategists such as Asterionella formosa, Acanthoceras zachariasi and Tetrastrum triangulare. Marked seasonal periodicity (including autogenic succession) occurred in Lake Rotomanuka North, the only warm monomictic lake within the series. Total α diversity (402 species) was higher than that of any other group of intensively studied New Zealand lakes, but compositional overlap at both generic and specific levels was low, with only 24 species being found in all nine lakes. Of these, the most common and ecologically versatile phytoplankters were Closterium acutum var. variabile, Cryptomonas marssonii and C. ovata, Cyclotella stelligera, Monoraphidium contortum and Trachelomonas volvocina. Mean total phytoplankton biomass and density ranged from 0.7 to 72.2 g m³ and 0.4 to 11.6 pu 1⁻¹, respectively, and comparisons with other quantitative phytoplankton studies indicate that some of the study lakes (Maratoto, Ngaroto and Rotomanuka South) are the most productive recorded in New Zealand to date. Eutrophic waters and rich organic sediments, together with a combination of both stratified and frequently mixed water columns, resulted in relatively high euglenophyte species diversity. Conversely, the number of desmid species was relatively low. Zooplankton exclusion experiments using limnocorrals were carried out in an almost clear-water lake (Rotomanuka North) and in a darkly-stained lake (Maratoto). The results suggest that a reduction in grazing pressure markedly influenced phytoplankton community structure in the former, causing shifts (in terms of biomass) from communities dominated by K- strategists (Microcystis aeruginosa or Peridinium cinctum) to smaller, fast-growing species (Cyclotella stelligera or Coelastrum microporum). Reduced herbivory also permitted increases in the number of taxa and total biomass of small edible phytoplankters (GALDs ≤ 20 μm), together with an increase in the number of euchlorophyte species. Similar responses were not apparent in dystrophic Lake Maratoto, suggesting that the stressful physico-chemical regime was the major regulator of community structure, and that trophic organisation within the two systems differed markedly, with energy transfer in the latter operating largely through a heterotrophic-based food chain.
An experimental study of the state of equilibrium in an inductively-coupled plasma torch
(The University of Waikato, 1987) Miller, George Paul; Liley, Bruce
An experimental study of the state of equilibrium existing in an atmospheric pressure argon inductively-coupled plasma torch (ICPT) has been undertaken using several diagnostic methods. In particular, a relaxation technique was used which involved pulsing off the RF field rapidly (< 3 μs) and monitoring the subsequent intensity changes in the optically-thin excited argon I spectral lines. The removal of the RF field is accompanied by a sharp intensity increase persisting for about 18μs before falling monotonically. This effect is explained in terms of the theory of collision-radiation decay of a plasma. The increase in spectral line intensity is used to ascertain whether the optically-thin excited Ar I states conform to a Boltzmann distribution for various operating conditions of the ICPT. For those cases where the excited states are close to a Boltzmann distribution, this method is used to determine the difference in temperature between the electrons (Tₑ) and the heavy particles (Tg) as well as the electron temperature. In addition, the same technique applied to a near saturated (optically thick) Ar I spectral line (811.5nm) is used to observe changes in radiative losses from the plasma. The results obtained show that a single flow (coolant only) ICPT plasma is in a state of pLTE in the central regions (r < 7mm). Not only do the optically-thin excited Ar I states conform to a Boltzmann distribution but centrally Tₑ = Tg to closer than 3% and Tₑ ≈ 10,000 K. The introduction of a second (aerosol) flow axially through the plasma is shown to cause a deviation from excitational equilibrium across the entire plasma radius. Increasing this flow from 1 1/min to 2 1/min appeared to return the plasma to a state of excitational equilibrium, but the temperatures obtained became inconsistent with the validity of Saha’s equation, i.e. indicating a non-Boltzmann distribution of the Ar I states. The radiative losses are increased significantly. The introduction of certain aerosols viz, 4%H₂ 4%Air, H₂O and KC1, into the plasma are shown to have negligible effect on the state of equilibrium. Four different methods used to obtain the electron density, (Stark broadening, interferometry, absolute intensity of the continuum, and Saha’s equation calculations) were compared for various cases. With a single flow plasma the results were consistent, and are typically in the range 10²¹ - 10²² m⁻³. With the introduction of the second flow, the method based on Saha’s equation yields results inconsistent with the other methods, confirming the significant deviation from equilibrium for this system. Calculations show that the deviation from excitational equilibrium is consistent with convective losses resulting from the forced flow of argon through the torch.
Smelt (Retropinna retropinna) population dynamics and predation by rainbow trout (Salmo gairdneri) in Lake Taupo
(The University of Waikato, 1984) Stephens, R.T. Theo; Chapman, M. Ann; Green, John D.
This study examines smelt (Retropinna retropinna) population biology in Lake Taupo, New Zealand, and describes the development of a model which simulated their population dynamics and interactions with rainbow trout (Salmo gairdneri), their principal predator. The model was used to predict the effects of variation in habitat features on smelt population processes and on their consumption by trout. Implications for fisheries management are discussed. The smelt population was comprised of three year classes. The juvenile 0+ year class occupied only the pelagic zone and fed exclusively on plankton whilst the adult 1+ year class also occupied the littoral zone and insects present there were included in their diet. A few smelt either failed to spawn at two years old or survived spawning. These grew rapidly, fed on larval bullies (Gobiomophus cotidianus) and spawned in late winter. Juvenile smelt reached 28-34mm FL after one year, 40-55mm FL after two years and 60-110mm FL when nearly 3 years old. Growth occurred all year but was most rapid between May and November. Spawning commenced in October when adults first became abundant in the littoral zone and continued until April. Females often recovered and spawned a second time, 6 - 8 weeks after the first spawning. Males were sexually active for an extended period. Eggs were scattered over sandy areas along beaches in water less than 3.0m deep and in the lower reaches of tributary streams where water currents were sufficient to prevent formation of algal mats and deposition of silt or detritus. Egg mortalities were correlated with water temperature but not with their density, which reached 5000m⁻² off Waihaha Beach and 40,000⁻² in the Waihora and Whanganui streams. Habitat perturbations caused by extreme weather conditions were thought to cause the most serious egg mortalities. Starvation was probably the principal source of larval mortality as there was little predation on 0+ smelt. Larger (730mm) 1+ smelt were the most important item in the diet of rainbow trout, comprising over 80% by volume of items eaten. Trout tended to select the larger smelt available and the intensity of selection was correlated with measures of smelt abundance. Trout generally gathered in places where 1+ smelt densities were high. Smelt population dynamics were simulated using length and density dependent models for movements between habitat zones, feeding, growth or starvation, breeding and predatory mortality. The form of simulated length frequency distributions largely determined the rates of these processes and was itself modified by the operation of each process. Modal groups occurred at lengths where food intake was equivalent to metabolic maintenance requirements and this was controlled by the interaction of diet breadth, the size structure and quantity of the food resource and the number of fishes sharing the same food particle size range. Growth of modal groups was controlled both by the duration of the spawning season and by seasonality in food resource quantity and size structure. Pelagic productivity and the ratio of littoral to pelagic habitat area were the most influential habitat features controlling smelt densities while densities of medium sized (30-55mm) smelt and water clarity were the most important factors controlling simulated quantities of smelt eaten by individual trout. Trout predation exerted little influence on simulated smelt population dynamics and consequently, the quantity eaten by individual trout was little affected by trout density. This result and comparison with trout stocking rates used in Canada suggest that a 1 - 2 order of magnitude increase in numbers of trout released annually into the larger Rotorua lakes would not significantly reduce their growth rates.
Competitive interactions in a dairy pasture containing paspalum (Paspalum dilatatum Poir,) following the introduction of ryegrass (Lolium perenne L.)
(The University of Waikato, 1984) Thom, Errol; Edmonds, A. S.
A series of trials investigated the contribution of introduced grasses (Lolium perenne and Bromus catharticus) to seasonal production of a high yielding dairy sward containing paspalum (Paspalum dilatatum). The persistence of the introduced species was also determined. Autumn overdrilling improved (<500 kg DM/ha) herbage production in the following winter/spring and autumn, but thereafter differences between drilled and undrilled swards disappeared. The monitoring of individual plants showed that there were high summer losses of introduced plants; up to 56% were lost by one year after drilling. The contribution of Bromus catharticus to herbage mass was less than that for Lolium perenne, as summer losses of the former plants were higher than for the latter because of increased susceptibility to direct ‘animal effects’ (eg. ‘pulling’). Bromus catharticus was therefore excluded from subsequent experiments. Summer growth of introduced plants was more restricted when they were closely associated with established paspalum than with other resident species, and large plants had better summer persistence than small plants. Manipulation of the light environment of the introduced ryegrass plants by regular clipping (10 mm stubble) of surrounding resident herbage markedly improved their ability to survive summer management and environmental stresses. The introduced plants were able to attain a large average size (20 to 50 tillers per plant) before the onset of summer. Summer losses of introduced plants were higher when grazed at a short (2-3 week) rather than a long (3-4 week) interval and if paspalum was a close neighbour. About 20% of total losses were related to direct cow damage, namely, severe grazing, ‘pulling’, dung and urine deposition, and trampling. The latter effects may be important where stocking densities are high. Other treatments such as late-winter/early-spring application of nitrogen fertiliser and irrigation during summer/autumn, failed to improve persistence of introduced ryegrass. One of the various ecological strategies that gives paspalum a competitive advantage over ryegrass is its ability to accumulate large reserves of carbohydrate. Measurement of nonstructural carbohydrate accumulated in above-and below-ground organs indicated that these reached a maximum for both species towards the end of the period of their most active growth. At this time the nonstructural carbohydrate level for paspalum at 1050 kg/ha, was four times greater than that for ryegrass. Possible practical methods for improving the persistence of ryegrass introduced into established swards are discussed.
Wave climate and sediment transport within Tauranga Harbour, in the vicinity of Pilot Bay
(The University of Waikato, 1988) de Lange, Willem P.; Healy, Terry R.; Nelson, Campbell S.
Previous studies of hydrodynamics and circulation in Tauranga Harbour, a meso-tidal estuarine lagoon (168km² total area), have concentrated on tidally-induced processes. However, non-tidal processes, such as wind generated waves, are also responsible for sediment transport in estuaries. This study was initiated to characterise the wave climate and investigate the effect waves have on sediment transport and deposition within the southern basin of the harbour (112km²), particularly adjacent to the Port of Tauranga in the vicinity of Pilot Bay. A review of previous investigations of the hydrodynamics and sedimentology of Tauranga Harbour was undertaken, and predictions concerning tidal circulation patterns and sediment transport pathways were examined in light of more recent data. Two model-based studies were considered in detail: the physical model run by the Wallingford Hydraulic Research Station; and the numerical models used by the Tauranga Harbour Study (THS). Both methods simulated large-scale circulation patterns reasonably well, the numerical model results being more exact than those of the earlier physical model. However, discrepancies were evident when considering more local circulation patterns, such as in Pilot Bay. Tidal circulation patterns and sediment facies distributions for Pilot Bay were compared with detailed model predictions from the two previous studies. Both failed to correctly define the circulation present, although the THS numerical sediment transport model did agree with the facies distribution. However, the facies distribution is relict, resulting from flow conditions prior to port development. Wind and pressure parameters were measured to assess the role local weather conditions play in determining the wave climate within the harbour. The harbour weather patterns are dominated by a diurnal sea breeze cycle which results in a relatively high average speed of 4ms-¹ compared to inland locations. To define the wave climate, two main groups of waves were considered: high-frequency (short-period) waves, including wind-generated waves; and low-frequency (long-period) non- tidal waves, including seiches, storm surges and tsunamis. The wave climate within Tauranga Harbour is dominated by wave energy transmitted through the harbour entrance. This source accounts for ~70% of the energy in the average harbour spectrum; local wind-generated waves account for ~9%; and the rest represents low frequency waves, including tides. A relationship, based on the JONSWAP spectral form, was derived to predict the local wind-generated component of the wave field. The equation is more peaked than the normal JONSWAP form, reflecting the extreme limiting conditions found inside the harbour. Seiching occurs frequently, usually in association with local winds exceeding 9.5ms⁻¹, but also in response to external forcing by tsunamis and large swell waves. Analysis of the seiche frequencies indicates that seiches are not controlled by harbour channels and dredged shipping basins. The largest oscillations within the harbour are caused by tsunamis and storm surges. Normally high-frequency waves inside the harbour are too small to move significant quantities of sediment, except when breaking or in very shallow water. However, wave-induced suspension of sediment combined with tidal currents can produce large sediment fluxes, particularly over the extensive intertidal regions of the southern basin (64km²). This process is most significant for regions where tidal velocities are below sediment threshold (<0.35ms⁻¹). The annual sediment fluxes for shallow regions with low tidal velocities are comparable to those occurring in major tidal channels within the harbour. A renourished beach in Pilot Bay was monitored between 1983 and 1987. Based on measured volumetric changes the renourished beach is expected to last for between 7 and 16 years. The net sediment flux measured within the nearshore zone is in close agreement with the Tauranga Harbour Study numerical model predictions. Textural analyses of monthly sediment samples were used to predict sediment transport directions. The method employed produced directions consistent with the observed patterns of erosion and accretion.
Understanding decimal numbers: an investigation of student meaning constructions in intermediate and high school
(The University of Waikato, 1986) Carr, Kenneth Colin; Katterns, Robert; Carr, Malcolm
This study grew out of informal observations of the poor achievement of 13 year old New Zealand students with decimal numbers. These observations were confirmed by the results of large-scale quantitative tests with 11 to 14 year olds both in New Zealand and overseas. The research design combined quantitative and qualitative approaches. Initially a decimal numbers survey was administered to a sample of 11 to 14 year olds (n = 102). Next a series of stimulus cards was constructed based on the survey results and the researcher’s observations. These cards formed the basis of interview protocols for a longitudinal study of 11 to 14 year olds (n = 28) over two years. Additionally, the individual interviews investigated the students’ views of learning mathematics and mathematics teaching, including their affective responses to decimal numbers and mathematics. The research was influenced by the constructivist view of learning in which the emphasis is on the individual actively constructing his/her own interpretations from incoming stimuli. In particular, use was made of the generative learning model to account for students’ constructions of meaning. Students employed these constructions of meaning, or mini-theories, to describe and explain their ideas when solving problems with decimal numbers. The findings gave further support to a constructivist view of learning mathematics, and pointed to the strong influence of affective variables in mathematics learning. It was considered that the generative learning model, with its strong cognitive emphasis, may be criticized for its inattention to attitudinal factors. As well, (and contrary to generative learning model postulates) the research suggested that learning was often of a fragmented and situation-specific nature and that students held incorrect mini-theories without testing them against a number of existing ideas. The implications of the findings for teaching and learning, the curriculum, assessment procedures, and in-service and pre-service teacher education are discussed in the final chapter.

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