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Generics in Go and lambda lifting
(The University of Waikato, 2026) Levy, Tom; Reeves, Steve
This thesis examines the history of generics in the Go programming language, and analyses two specific issues that arise: local type declarations inside generic functions, and embedded type parameters. This work includes a novel algorithm for lambda lifting, a problem closely related to the handling of local types inside generic functions in Go. The correctness of this algorithm is proven with respect to both a specification from the literature and additional specifications. Parts of these proofs are formalised using the Lean 4 theorem prover. For embedded type parameters, this thesis proposes sound member promotion rules for type parameters embedded in struct types in Go. The testing methodology used in this thesis centres around "checking", which strikes a middle ground between formal verification and testing.
Who reports intimate partner violence in Aotearoa New Zealand: Comparing episodes across reporter categories
(The University of Waikato, 2026) Bridge, Danika; Polaschek, Devon L. L.
Much research has examined the different types of people who report intimate partner violence to the police and what makes them more or less likely to do so, typically focusing on victims and third parties separately. However, little research has examined the range of roles reporters can take, and the types of demographic, relationship, and episode characteristics that are associated with those roles. In this study we examined intimate partner violence episodes reported to New Zealand police (n = 323) and found that victims and third parties reported episodes at similar rates. Of the third parties, neighbours most frequently reported episodes, followed by family members, members of the public, friends, and then other types of services (e.g., ambulance staff). Third parties known to the dyad reported less frequently than those unknown to them. We also found that victims were more likely than third parties to report when there was a history of family violence and when episodes involved their former partner. Third parties were more likely than victims to report episodes involving verbal harm by the aggressor, but there was no association between physical harm and who reported the episodes. These results indicate that variables influencing the visibility of the episode are more important to who reports than indicators of severity. We identified several variables worth further research and suggested methodological changes that could provide more insight into the types of episodes reported by reporters of different roles.
Evaluation of biogas production and operational feasibility of anaerobic co-digestion of P6 and DAF sludge from a dairy factory
(The University of Waikato, 2026) Li, Jian; Lay, Mark C.
Dairy factory wastewater treatment is commonly associated with high organic loading, energy consumption and sludge management challenges. High-strength side streams from dairy processing may contain recoverable organic energy and therefore have potential for anaerobic digestion and biogas production. This study evaluated the laboratory-scale anaerobic co-digestion feasibility of two high-strength dairy factory waste streams, P6 and dissolved air flotation (DAF) sludge, with particular focus on biogas production, pH control, chemical dosing demand, total solids/volatile solids (TS/VS) behaviour and recovery after feeding interruption. The experiment was conducted using fifteen 1 L bottle anaerobic digesters operated under mesophilic conditions at approximately 34 °C. Four linked experimental stages were used. Stage 1 was a batch start-up test under different inoculum-to-substrate (I/S) conditions. Stage 2 was a transitional operation using a fixed P6:DAF ratio of 85:15. Stage 3 was a long-term semi-continuous co-digestion stage comparing P6:DAF ratios of 80:20, 85:15, 90:10 and 95:5. Stage 4 examined shutdown, re-feeding recovery and short-term response after a second shutdown. The main analytical indicators included cumulative and interval biogas production, pre- and post-dosing pH, NaOH addition, TS/VS, VS-based apparent conversion and limited gas composition results. The results demonstrated that mixed P6 and DAF sludge could produce measurable biogas under anaerobic conditions. In Stage 1, the I/S = 1:14 group showed the highest blank-corrected cumulative biogas production and the strongest VS-added-based specific biogas response under the batch test conditions. Stage 2 helped reduce some initial differences among reactors and provided a more comparable basis for the later ratio comparison. In Stage 3, P6:DAF = 90:10 produced the highest net cumulative biogas increase, while P6:DAF = 80:20 showed strong performance and better within-group consistency. The P6:DAF = 95:5 group showed weaker net gas production and greater individual-digester variation. Stage 4 showed that residual gas production continued during shutdown and that gas production could recover after re-feeding, although recovery behaviour differed among groups and was affected by operational history and temperature disturbance in some digesters. Preliminary application of the Stage 3 results to available Tatua site-flow data indicated an estimated raw biogas flow of approximately 582–926 m³ day⁻¹, an indicative active digester volume of approximately 11,300–16,500 m³, and an apparent VS-load reduction of approximately 4.46–5.61 t day⁻¹ under the mean-flow scenarios. Because methane fraction was not continuously monitored, the gas production results were interpreted mainly as biogas production performance rather than strict methane yield. In addition, COD was not measured, and VS-based apparent conversion was treated as a relative indicator rather than a complete mass balance or biochemical conversion efficiency. Overall, the study indicates that anaerobic co-digestion of P6 and DAF sludge has technical potential for biogas production and resource recovery. However, practical implementation would require improved methane monitoring, more detailed stability indicators, longer-term operation, process optimisation and pilot-scale validation.
The right time: Women, medicine and maternal age in 1980s Aotearoa New Zealand
(BMJ, 2024) Greenhalgh, Charlotte
In the late twentieth century, increasing numbers of women in wealthy nations waited until they were aged in their 30s to give birth and become parents. This article examines responses to the changing demographics of maternity among social researchers, doctors, pregnant women and mothers in Aotearoa New Zealand. The article analyses raw research data from historical social survey projects The Right Time (interviews completed in 1982–1983) and Motherhood After 30 (1987) by the grassroots organisation the Society for Research on Women in New Zealand. Surveys, statistics and increasingly direct evidence from research participants symbolised modern social life in the mid-twentieth century. Yet, in 1966, women in Wellington, New Zealand concluded that they had been largely ignored in this endeavour. A group of volunteers pledged to produce the missing data and therefore improve policy making. This article analyses the Society’s publications and interview schedules to uncover how researchers, medics, pregnant women and mothers forged new connections between age, pregnancy and parenting during the 1980s. During this time, pregnant women advocated for a new model of prepared and mature maternity. A few years on, however, many among them identified the persistence of traditional gender roles that disrupted their plans. At the same time, physicians and public health officials in wealthy nations began to teach women to associate conception at older ages with increased risks, especially of genetic anomalies. Social research archives reveal tensions between these new, population-level recommendations and women’s proactive approaches to planning their lives and families. New Zealand’s distinctive survey records help to explain the impacts of new medical tests, reproductive technologies and public health recommendations in the context of women’s fresh approaches to maternity during the 1980s.
Exploring factors that influence the use of the paediatric early warning system : A mixed method study within the paediatric inpatient setting at Te Whatu Ora Waikato
(The University of Waikato, 2026) Clayton, Tarryn; Heath, Samantha
Background: The paediatric early warning system (PEWS) was introduced as a nationally standardised tool in New Zealand to identify and escalate clinical deterioration in the paediatric population. Although the PEWS is implemented across the country, audit data at Te Whatu Ora, Waikato indicate that there is variability to adherence to the mandatory escalation pathway. There is limited research from the New Zealand context that explores the experiences of nurses using the PEWS in practice and what factors influence decision making when using the PEWS. Objective: To explore the factors that influence nurses’ use of the PEWS assessment tool and mandatory escalation pathway in a paediatric inpatient ward at Te Whatu Ora, Waikato, and to identify any educational requirements to support the use of the PEWS. Participants: Participants were registered nurses employed in the paediatric medical ward (E5) and paediatric surgical ward (E4) at Waikato Hospital. Thirteen nurses participated in three focus groups and 31 nurses completed a quantitative survey. Methods: This research is a pragmatic exploratory mixed methods design. Phase One involved three semi structured focus groups, with data analysed using Braun and Clarke’s (2022) thematic analysis. The focus groups findings informed the development of a quantitative Likert scale survey used in Phase Two. Descriptive statistics were used to analyse the surveys, and the qualitative and quantitative findings were integrated to provide a comprehensive understanding of the factors that influence use of the PEWS. Results: Five key themes were identified: Clinical Judgement and Experience, Time Pressures, Professional Responses and Communication, Unique Factors Presented by Children, and Adherence to PEWS and Education. The survey findings validated these themes, highlighting how workload pressures, communication processes, clinical judgement, and paediatric-specific factors influence nurses’ use of the PEWS. Conclusion: Nurses view the PEWS as a valuable tool that supports patient safety, communication, and recognition of deterioration in paediatric patients. However, the use of the PEWS was influenced by factors that include the balance between clinical judgement and mandatory escalation, workload and time pressures, interprofessional communication, paediatric assessment challenges, and documentation requirements. While participants felt adequately educated in the PEWS use, education alone was not enough to ensure consistent adherence to the PEWS escalation pathways. Successful implementation requires ongoing simulation-based and interprofessional education, organisational support, adequate staffing, and understanding how clinical judgement can be utilised with the standardised pathway. These findings highlight the need for a systems-based approach to improve the use of the PEWS and enhance paediatric patient safety.