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Fault-rupture induced river avulsion susceptibility: developing a national model for New Zealand.
Full text linkSurface-rupturing earthquakes can trigger the sudden avulsion of river channels, causing rapid and persistent coseismic flooding of previously unaffected areas. This phenomenon, known as fault-rupture-induced river avulsion (FIRA), occurs when fault displacement significantly alters river channel topography. The importance of understanding FIRA as a secondary seismic hazard was highlighted by events during the 2010 Darfield and 2016 Kaikoura earthquakes in New Zealand.
This thesis develops a national model to identify and quantify FIRA susceptibility across New Zealand by integrating hydrological datasets (NIWA RiverMaps and Flood Statistics) with active fault information (NZ Active Faults Database and RSQSim earthquake simulations). The methodology applies the F-index framework proposed by McEwan et al. (2023), which quantifies FIRA potential based on the ratio of fault throw plus discharge-dependent depth to bank full depth at each fault-river intersection.
The model successfully identified 3,796 potential FIRA-susceptible fault-river intersections nationwide, with 451 involving waterways equal to or larger than the Hororata River. Regional analysis revealed higher concentrations of FIRA-susceptible sites in the Bay of Plenty, Canterbury, and Marlborough regions. Validation against historical events showed the model effectively located known FIRA occurrences from the Kaikoura and Darfield earthquakes, though with some limitations in accurately predicting F-index values due to complex fault displacement patterns and challenges in modelling bank full depths of large, braided rivers.
This research establishes New Zealand's first nationwide assessment of fault-induced river avulsion susceptibility. The approach creates a structured methodology for identifying high-risk fault-river intersections and determining which sites require thorough localised examination. The methodology developed offers a template for similar assessments in other tectonically active regions and contributes to improving earthquake hazard assessment and disaster preparedness planning
Impact Assessment Frameworks for Nature-Based Climate Solutions: A Review of Contemporary Approaches
Full text linkThis study provides a comparative analysis of ecological impact assessment (EcIA) guidance for the design and approval stages of carbon sequestration and emission reduction projects, which are rapidly proliferating in response to the global need for climate change mitigation. Previous reports of negative effects on biodiversity from such projects suggest a need for more robust project design and assessment processes to improve synergies with conservation. Using a content and thematic analysis methodology, we compared four published frameworks that guide the assessment of carbon projects in natural environments. The results showed considerable variation in environmental assessment components including the level of attention to ecosystem services and the identification of areas of high conservation value that may require specific protections. There was a general lack of guidance on the inclusion of indirect and supply chain effects despite their relevance to ecological impacts. Critically, guidance in common use in the climate mitigation sector shows differing applications of the baseline and counterfactual scenarios that are used to quantify impacts. We discuss the need to focus assessment and reporting on comparisons with recent baselines to identify the contributions of individual projects and enable adaptive management and show how aligning with the concepts of Nature-based Solutions and nature-positive could be used to reimagine the role of EcIA to achieve these objectives. If these current weaknesses can be improved, EcIA has the potential to become an important implementation pathway for the conservation–climate change nexus due to its pivotal role in project design and approval processes. Conversely, a failure to reliably address these aspects will undermine the utility of EcIA as a decision support tool for sustainable development. We encourage the further exploration of EcIA practices in this direction and highlight the pressing need for reliable comparisons to support more strategic and sustainable solutions for both the conservation and climate change agendas
The migrant experience of decent and meaningful work : a qualitative exploration.
Full text linkNew Zealand increasingly attracts skilled migrants seeking personal and professional growth, safety, and political freedoms. However, many migrants arrive in New Zealand and realise that their qualifications are not recognised by employers, often forcing them into work for which they are overqualified. Under these conditions, questions arise about migrants' access to – and experiences of – decent and meaningful work. Research examining decent and meaningful work among migrants, particularly those who are overqualified, is scarce and primarily has focused on barriers to accessing decent and meaningful work. The present study addresses gaps in the literature by qualitatively exploring how skilled migrants’ views and experiences of decent and meaningful work evolve and inform career and life decisions and outcomes. Sixteen semi-structured interviews were conducted with skilled migrants in New Zealand who had worked in roles for which they were overqualified at some stage in their careers. Thematic analysis identified four key themes that characterise skilled migrants’ experience of decent and meaningful work: access to meaningful work, redefining the role of work, deriving meaning amidst occupational change and professional identity resilience. This study makes important contributions to the literature by providing insight into the subjective and evolving nature of decent work, and how migrants experience meaningfulness in work roles and environments where traditional sources of work meaning may be compromised. This study offers valuable practical implications, demonstrating that promoting and facilitating decent and meaningful work for skilled migrants enhances their overall wellbeing and quality of life and how doing so, is in the best interests of organisations
Synthesis and characterisation of poly glycerol sebacate bioelastomers.
No full textContext: Surgical meshes have been used in multiple areas of the human body, especially to treat hernia defects. However they are controversial regarding postoperative complications. Research Motivation: Bioelastomers are not currently used in the commercial production of surgical meshes. Nonetheless they have potential advantages in that the mechanical properties of bioelastomers may provide mechanical stimuli that promote faster wound healing in soft tissue applications. Objectives: There is need to better characterise the bioelastomers, i.e. determine those properties that are important to biomedical engineering designers who are considering potential future implant applications. Results: This thesis describes the characterisation of one of the bioelastomers, specifically polyglycerol sebacate (PGS), by reporting on chemical structure, thermal behaviour (glass transition temperature, crystallisation temperature, shrinkage, decomposition temperature), and mechanical properties (Young’s Modulus, strength, elongation). The work also reports on the use profile for the material, i.e. the medical implications (hydroscopic properties), manufacturability of meshes, and the product design implications. Findings: Two synthesis routes were attempted, microwave and conventional inert gas and oven. This work e established that the microwave route is not currently reliable. Conventional synthesis for PGS using inert atmosphere and curing in a vacuum oven, was successful. Originality: This work makes the novel contribution of showing a comprehensive characterisation of poly glycerol sebacate, including the rheology which has not previous been reported in the literature. In addition, the work shows that the curing temperature of 140 oC as cited in the literature, resulted in a material with the correct chemical composition but showing different molecular segmental thermal behaviour. The work makes an additional contribution of offering a conceptual model of how the factors affect mesh infection, chronic pain, and hernia recurrence. Using this a risk assessment framework was developed. This quantifies risk of complications, based on the frequencies reported in the literature
Nonparametric instrumental variable estimator performance evaluation in econometrics
Full text linkInstrumental Variables are a tool widely used in statistics and econometrics, most often utilized to address the problem of endogeneity. The aim is to achieve consistent estimation with the knowledge that the dependent variables have a correlation of unknown degree with the error terms in a model. This would make the expectation of the error non-zero, which violates standard modelling assumptions. Instrumental variables are variables that they can be utilized in said models such that the expectation of the error of a model given the instrumental variable returns to zero, allowing for consistent estimation.
Many methods of performing instrumental variables estimation are available in academic literature. Some popular ones are kernel estimators (Singh 2019 [9], Meunier 2024 [10]), series estimators (Crain 1974 [3], Efromovich 2010 [2]) and spline estimators (Beyhum 2024 [1]). Estimation via nonparametric methods (Newey 1988 [11], Horowitz 201 [8], Darolles 2011 [4], Chetverikov 2018 [5], Loh 2023 [7]) is of particular interest as they do not enforce any assumed form of an underlying relationship between the explanatory and dependent variables and relies on the data itself for modelling the underlying distribution, at the cost of requiring data of large sample sizes for effective utilization. In previous works, academics have focused on comparing single methods to a naive baseline. Much of the work is silent on how to choose different methods of NPIV estimators in the face of differing datasets.
The contribution of this thesis is the comparison by performance evaluation of several methods, with an emphasis on methods that are nonparametric by nature and offer indirect solutions or some other compromising workarounds to common problems arising in this topic such as the computational intensity of algorithms and the ill-posedness of inverse problems. Specifically, we will implement, evaluate and compare the performance of four nonparametric estimation methods in literature to handle regression problems with an instrumental variable on data stemming from different data generating processes.
This thesis is divided into four main parts. Chapters 1 and 2 offer an introduction to the topic, motivation and mathematics of nonparametric instrumental variable regression. Chapters 3 and 4 discuss the background and algorithm of four popular methods, two apiece. Chapter 5 supplies the metric and computational comparison of the performance of the four methods against simulated data. Chapter 6 concludes the thesis with a summary of what has been covered and what further work there is to be done
3D Robotic Control of Optical Swarms at Micro-Scale
No full textOptical force-induced assembly is a promising yet scarcely explored approach for developing functional tools and objects at the microscale, with a wide range of potential applications. Our previous work was the first to investigate the manipulation of these assemblies in the XY plane. Here, we expand on these techniques by systematically exploring optical trap manipulation with the addition of Z-axis control. Manipulation of the Z-axis is referred to as axial displacement and is a viable approach for actively manipulating the assembly morphology. Experiments are conducted for the first time to explore and detail the response of the assembly during active 3D trap manipulation, informing the development of an autonomous control algorithm over the 2D area of the assembly during motion. This control presents techniques to increase assembly stability or alter the area of the assembly for tasks such as passing through constrictions. This work aims to develop the control techniques required to create
a unique micromanufacturing approach inspired by the Kilobot thousand-robot swarm
Advancing urban forest and ecosystem service assessment through the integration of remote sensing and i-Tree Eco: A systematic review
Full text linkUrban forests support the health and well-being of billions of people living in cities globally. To better manage urban forests, it is crucial to assess their ecosystem services. This systematic review analyzes two established urban forest assessment approaches—i-Tree Eco and remote sensing—which have developed independently but hold significant potential for integration. The review, comprising the years 2008 to 2022, evaluates the current status of both methods in assessing urban forest structure and ecosystem services, highlighting opportunities for synergy. The literature shows that while both approaches primarily focus on regulatory services, remote sensing offers more versatile tools for assessing a broader range of ecosystem services beyond i-Tree's standardized scope. Remote sensing holds potential to enhance i-Tree Eco by providing structural and location-specific data at scale, albeit with varying accuracies. Studies have shown that LiDAR data reliably derives tree height and crown width, and that, in combination with multispectral and hyperspectral imagery, it enhances species identification. Additionally, mobile, and terrestrial laser scanners accurately estimate diameter at breast height. However, gaps remain in using remote sensing to assess crown characteristics like crown missing and dieback, which, though not critical, are useful for enhancing ecosystem service estimates in i-Tree Eco. Despite the potential of remote sensing to automate urban tree inventories, limited research has shown its successful integration with i-Tree Eco. Future research should standardize remote sensing techniques for assessing tree crown health. Additionally, further work is needed on quantifying differences between remote sensing and groundbased measurements, with the aim of evaluating uncertainty levels and understanding how these uncertainties impact the reliability and usefulness of data for policymaking and planning
Development of the Te Reo Māori Simplified Matrix Sentence Test
Full text linkKaupapa Māori audiological research has highlighted the need for te reo Māori
hearing assessments to enable equitable hearing healthcare across Aotearoa (Lowe,
2023; Lowe et al., 2024). Currently, hearing healthcare service delivery follows a
westernised, one size fits all model, which disadvantages and contributes to
inequitable health outcomes for Māori. This is particularly concerning given that
Māori are overrepresented in every healthcare statistic.
The objective of this study was to develop the “te reo Māori Simplified Matrix
Sentence Test”. Matrix sentence tests are a type of speech-in-noise hearing
assessment that use syntactically fixed yet semantically unpredictable sentences,
each originally containing five words (name, verb, number, adjective, object)
(Hagerman, 1982; Trounson, 2012; Stone, 2016). Due to the cognitive demands of
conventional matrix sentence tests, a simplified 3 x 10 matrix version was developed
primarily for paediatric use but found to be valuable for a wider demographic of
individuals. The development process of the te reo Māori Matrix Sentence test
involved selection of kupu, consultation and refinement through wānanga, recording,
editing and level adjustment of candidate stimuli.
Prior to 2024, there were no validated te reo Māori audiological diagnostic
assessments or screening tools available, meaning that individuals whose first
language is Māori were unable to be tested in their preferred language, making
currently used speech assessments neither reliable nor valid for this purpose. This
issue is particularly significant given the resurgence in te reo Māori. Without
incorporating linguistically and culturally appropriate tests the profession is unable to
meet this requirement, compromising equity, accuracy and failing to uphold its
obligations under Te Tiriti
