ResearchSpace@Auckland
University of Auckland Research Repository - ResearchSpace
ResearchSpace is an online archive for the University of Auckland and contains full text theses and other research outputs.
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Recent Submissions
Sexcapades, Drug Hazes and Terrorist Attacks: Exploring Expatriate Work and Well-being in Fortified Compounds in a Hostile Environment
(ResearchSpace@Auckland, 2024) Mackay, Samuel David; Boxall, Peter; Smith, Peter
Background: Fortified compounds are used by organisations as a key strategy to reduce security risks to their expatriate employees in hostile environments. Despite growth in this practice, there has been little research to understand how these environments affect the individuals who work and live within them.
Purpose/aim: This qualitative study explored the experiences of expatriates who worked and lived in fortified compounds in Kabul, Afghanistan. It aims to contribute to our understanding of how individuals’ work and well-being experiences are shaped within such environments.
Design/methodology/approach: In-depth, semi-structured interviews were conducted with 36 expatriates (F=18, M=18) who lived and worked in compounds in Kabul between 2014 and 2021. Data was coded and thematic analysis applied to reveal new insights, including in relation to the notion of Total Institution and the Jobs Demands-Resources (JD-R) Theory.
Findings: Expatriates experienced extreme job demands despite—and due to—being placed in fortified compounds in a hostile environment. This included terrorist attacks, deaths of others, sexual harassment, overwork, and conflict with colleagues and managers. Many job resources were compromised in their implementation and did not necessarily address the demands expatriates encountered and some job resources—particularly those relating to security—generated additional job demands for employees. Expatriates adopted binge behaviours—whether proactive (e.g. exercise and social support) or self-undermining (e.g. sexcapades and use of drugs and alcohol)—to cope with the extreme demands and limited resources they encountered.
Conclusions: Findings indicate a new category of Total Institution is warranted and help to enhance the applicability of the JD-R model to extreme employment contexts.
Originality/value: This research adds to the extremely limited research on working and living in fortified compounds, highlighting the human resource management implications for the individuals and organisations involved.
Implications: This research has implications regarding coping for the individuals who work and live in fortified compounds, and regarding support for the organisations that place employees there. For decision makers, it raises broader questions regarding the appropriateness and sustainability of placing employees in such environments.
Keywords: Expatriation, Hostile environments, Fortified compounds, Job Demands-Resources Theory, Total Institution
Neural circuitry in motion: Computational modelling of motor cortical dynamics to understand human movement
(ResearchSpace@Auckland, 2023) Haggie, Lysea Chan; Besier, Thor; McMorland, Angus
Movement of the human body arises from a complex interaction between the activity
of the nervous system and the biomechanics of the musculoskeletal system. How
neurons of the brain and spinal cord produce purposeful, coordinated movements is
a fundamental question in neuroscience and motor control research. Computational
models offer a valuable tool to test theories and mechanisms underlying the challenge
of motor control. The primary motor cortex is the area of the brain with the most
direct influence and connections to producing voluntary activity in limbs. However, a
consensus on the link between motor cortex activity and the production of muscle
activity remains elusive.
Spiking neural networks (SNNs) represent the biological mechanisms of communication
between neurons via action potentials. A SNN model containing over 38,000
neurons and 160 million synapses was developed to represent a 1 mm2 surface area
of the motor cortex. The neural network model used realistic, physiological parameters
and connectivity to replicate the spontaneous firing behaviour of populations of
neurons in the motor cortex. A model of transcranial magnetic stimulation (TMS)
was also applied to the motor cortex model, resulting in the generation of highfrequency
(I-waves) at the spinal cord level, matching experimental observations. In
addition, the model was coupled with a musculoskeletal model of the upper limb
to simulate muscle contraction and multi-body dynamics, via a simple spinal cord
circuit controlling extensor and flexor muscles, showing the feasibility of coupled
brain-body models.
The motor cortex model is presented within a larger framework of modelling the
connection from brain to muscle that incorporates feedback pathways including
muscle spindles and Golgi-tendon organs, in addition to detailed muscle models. The
framework of this computational modelling approach uses multi-scale, multi-modal
modelling fitted where possible to experimental data to enable the observation of
emergent patterns of behaviour within the motor system. Using interdisciplinary
computational models to understand the neuromusculoskeletal system is widely applicable
and can be developed in conjunction with experimental work and hypotheses
of motor control.
History, Myth and Remembrance: How the Battle of Agincourt became a Symbol of British Exceptionalism
(ResearchSpace@Auckland, 2024) Jost, Ian; Phillips, Kim; Diggelman, Lindsay
This thesis is a study of how the medieval Battle of Agincourt has developed and flourished in English and British memory over the last six hundred years; how it has been mythologised into something much bigger than it actually was, and how that mythologisation enhances and augments notions of British (especially English) nationhood and self-worth. The central argument of the thesis is that the battle has played a major part in instilling into English (and British) consciousness a sense of a unique historical heritage of cultural, political and hegemonic exceptionalism.
The thesis will suggest that many different Agincourts have been constructed by historians, novelists and playwrights; its mythologisation and on-going appeal to social memory owes much to the public’s ability to choose which iteration of the event they prefer.
At least since Shakespeare’s time, writers of Agincourt have supported a perception of the battle’s uniqueness that combines a sense of continuity between what is perceived as the eternal propriety and decency of the ordinary Englishman, and his willing acceptance of the hierarchical social structure of crown, nobility and commoner.
The thesis historicises how this has happened; who and what were the main drivers, why and when. Context is all; without considerable reference to contemporary events, public responses to Agincourt would be almost incomprehensible. Building on those events, social movements, literary trends and innovations, and cultural norms, the thesis describes the relationship between Agincourt and the English/British people, and shows how, since immediately after the battle itself, it has positioned itself in the collective national memory as a moment of mythical – sometimes supernatural – incomparability.
Reactive Transport Modelling of Flow Through Porous and Fractured Media in Geothermal Systems
(ResearchSpace@Auckland, 2025-02) Altar, Dale Emet Sabater; Zarrouk, Sadiq J; Kaya, Eylem
This research uses reactive transport models (RTM) to analyse the hydrological, thermal, and chemical processes in hydrothermal environments, particularly geothermal systems. This research highlights RTM applications in experimental research, geothermal reservoir management and geological carbon dioxide storage. Comprehensive investigations reveal critical processes, challenges, and opportunities.
The methodologies and results of representative fluid-rock interaction models under high temperature and pressure conditions extending to the supercritical regime are explained. Accuracy gaps in reaction parameters are addressed by validating models against experimental and operational data and through sensitivity analyses. The primary simulation tool used is TOUGHREACT™, a non-isothermal multi-component reactive fluid flow and geochemical transport simulator.
This work begins through an in-depth review of existing research on RTM for geothermal applications, governing equations, and available tools. Specific transport and chemical interaction parameters and associated estimation methods are likewise explored.
The first numerical investigations focus on calibrated models for basalt-water interactions under subcritical and supercritical conditions. The utility of calibrated RTMs in assessing individual mineral reaction kinetics and equilibria in whole-rock experiments, ascertaining the geochemical properties of whole rock samples, and offering insights into alteration sequences are demonstrated.
Next, a natural state model for a theoretical two-phase liquid-dominated geothermal reservoir was developed. Modelled mineral alterations and fluid chemistry are compared to analogous natural systems. Permeabilities are shown to evolve with mineral alteration. Orogenetic processes for ore metals, e.g., gold, are likewise simulated, revealing how they form in a geothermal reservoir.
The application of reservoir RTMs for CO2 sequestration was explored next. Through the use of simplified 1D radial models, it is shown that dissolved CO2 in reinjected brine changes fluid chemistry, promoting mineral dissolution and impeding permeability loss caused by mineral scaling.
Finally, a theoretical 3D liquid-dominated geothermal reservoir model provides a more comprehensive analysis of CO2 storage potential and reservoir impacts, exhibiting both primary mineral dissolution and mineralisation trapping of CO2. It also reveals that CO2 injection may increase NCG content in produced steam over time through injection returns.
A Multifaceted Exploration Toward the Impact of Processing Techniques on Hempseed Protein Isolate
(ResearchSpace@Auckland, 2024) Dong, Xuan; Quek, Siew Young; Wai, Meng Woo
Hempseed protein isolate (HPI), obtained as a by-product following hempseed oil extraction, has garnered increasing interest due to its sustainability and nutritional quality. The production of HPI typically involves defatting hempseed, extracting protein, and finally dehydrating. Despite its rising popularity, the impact of various processing techniques on HPI remains under-explored, presenting a challenge for the food industry in utilising HPI effectively. This research endeavours to bridge these gaps by investigating the effects of various processing methods on HPI and exploring the bioactive properties influenced by enzymatic hydrolysis.
The impact of two prevalent industrial drying methods, spray drying and freeze drying, on the physicochemical properties, functionality, and digestibility of HPI was investigated. Both techniques modified the physicochemical and structural properties compared to undried-HPI. Notably, the protein denaturation temperature increased to approximately 90°C in both freeze-dried and spray-dried samples, compared to 82.5°C in undried HPI. Electrophoresis showed the disappearance of 26 and 17 kDa protein bands post-drying. In vitro simulated gastrointestinal digestion indicated that the digestibility of HPI improved after drying, but there was a 50% reduction in the release of free α-amino groups. Notably, freeze-dried HPI exhibited higher emulsifying stability and oil-holding capacity than the spray-dried sample.
Further investigation assessed the impact of processing steps at the proteome level. Specifically, the effects of alkaline and micellisation extraction methods, along with freeze drying and spray drying, on the proteome profile of HPI were analysed. Findings revealed that extraction methods impacted the protein profiles of HPI more than the drying methods. Specifically, micellisation-extracted HPI showed higher albumin, oleosin, and sulphur-containing protein levels than alkaline extracted HPI. The alkali-extracted undried sample (AU) showed more potentially allergenic proteins, including Hsp70 and triosephosphate isomerase, than its micellization-extracted counterpart (MU). Unique potential allergens were identified, including malate dehydrogenase and enolase in AU, and RuBisCo in MU samples. Both drying processes impacted the HPI proteome and reduced RuBisCo in the micellisation extracted HPI. Spray drying demonstrated a more pronounced impact on the proteomic profile of HPI than freeze drying.
The bioactive peptides release profiles of HPI samples were further explored through a comprehensive workflow combining in silico screening and prediction with in vitro validation. Using an in silico approach, 13 major HPI proteins were hydrolysed by 20 selected enzymes, predicting 20 potential bioactivities. With papain hydrolysis, dipeptidyl peptidase-IV (DPP4) and angiotensin-converting enzyme (ACE) inhibitory activities emerged as having the highest potential. In vitro experiments confirmed these predictions, with DPP4 and ACE inhibitory activities displaying IC50 values of 0.32–0.42 mg/mL and 6.8–9.17 µg/mL, respectively. A strong correlation (r2 = 0.96) was observed between the in vitro and the in silico predicted data when correlating with protein abundancy.
The findings of this study reflect the importance of selecting appropriate methods for optimising HPI processing in the food industry. These insights facilitate improved strategies for HPI production and its application in food products. Additionally, the research showcased a practical, integrative approach for predicting bioactive peptides in food proteins, providing valuable guidance on its processing to create value-added products.