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Evaluating RNA extraction methods for the detection of citrus viruses and viroids with RT-qPCR and HTS
Get PDFThesis (MSc)--Stellenbosch University, 2025.Dippenaar, M. 2025. Evaluating RNA extraction methods for the detection of citrus viruses and viroids with RT-qPCR and HTS. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/2e22d0ea-fba3-494f-a055-dc494803ae26The South African citrus industry is a vital economic role-player and certification, quarantine and disease management practices are reliant on accurate detection assays. Effective nucleic acid extraction is the cornerstone of various molecular detection techniques including traditional polymerase chain reaction (PCR) methods and high-throughput sequencing (HTS). The extraction method considerably influences the type, quantity and quality of RNA extracted and, therefore, the overall detection capability of the assay. As the popularity of HTS for application in diagnostics increases, it is imperative to evaluate nucleic acid extraction methods and to explore various sequencing methodologies to ensure that the entire pathogen detection pipeline is optimised. Illumina platforms have been extensively validated for this purpose but recently, Oxford Nanopore Technologies (ONT) has become a contending platform for integration. The continuous development of HTS necessitate the renewed comparison of sequencing platforms. This study aimed to identify an RNA extraction protocol that will enable the consistent, effective, and reliable detection of citrus virus and viroid RNA with reverse transcription quantitative PCR (RT-qPCR) and HTS. Overall five extraction protocols, cetyltrimethylammonium bromide (CTAB)/lithium chloride (CL), CTAB/ethanol (CE), acidic phenol buffer/lithium chloride/isopropanol (TL), sodium dodecyl sulphate (SDS)/isopropanol (SI) and CTAB/isopropanol (CP), were selected and pathogen quantities in citrus infected with citrus tristeza virus (CTV), citrus virus A (CiVA), citrus tatter leaf virus (CTLV), citrus dwarfing viroid (CDVd), citrus exocortis viroid (CEVd) and hop stunt viroid (HSVd), were evaluated with RT-qPCR and validated with Illumina HTS. Extracts from one protocol were then selected and used to compare Illumina and ONT virus and viroid sequencing capability. The extraction protocol had a significant influence on differential pathogen detection ability for both RT-qPCR and HTS. The CL method performed best for CTV while the SI method proved more sensitive for the other viruses. Viroid detection had increased variability with CE extracts containing more viroid RNA although CL extracts showed comparable amounts of CDVd. The CE protocol indicated potential debilitating effects on virus detection although a protocol modification showed increased virus and reduced viroid amount. Despite the differential pathogen extraction amongst protocols, all target pathogens could be detected with appropriate RT-qPCR replicates and combined bioinformatic approaches. This study emphasises that although multiple protocols can be effective, further selection and optimisation could enhance the performance. The SI extracts were selected to compare sequencing platforms and both technologies were able to identify all pathogens using both reference-dependent and independent methods. Illumina re-established its reputable high sensitivity, coverage and accuracy. ONT compensated for fewer pathogens reads and lower depth with longer reads that enabled reasonable genome coverage and sequencing identities comparable to that of Illumina when appropriate flow cell capacity (data amount) was used. This comparison between Illumina and ONT platforms highlights the strengths associated with each approach and offers new insights into the possible application of HTS within plant health surveillance and biosecurity programs. Present research serves as a foundation for the refinement of diagnostic pipelines in citrus pathology.Master
Teaching and learning critical citizenship through visual arts in the intermediate phase at three primary schools : the South African paradigm
Get PDFThesis (DPhil)--Stellenbosch University, 2025.Putter, M. J. 2025. Teaching and learning critical citizenship through visual arts in the intermediate phase at three primary schools : the South African paradigm. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/373bc02f-1c1c-44a9-b4e1-70d75f952a1bArt education at school could contribute to the holistic development of learners by creating opportunities to develop, hone and improve life skills that remain relevant throughout life. Visual Arts as a subject can create safe learning environments where learners can engage with critical issues related to their own lives, leading to the development of critical thinking through interactions with a learning community where learners regard and examine their own and others’ perspectives and opinions. Schools are not only institutions of academic performance, but also spaces where natural, real-life situations, conflicts and engagements occur. When learners receive social justice and critical citizenship education, they are able to learn beyond the learning material, procuring tools that will empower them now and as future adults who will be the architects of a future democratic South Africa. Our connection to our community governs our actions, and it helps us relate to and connect with one another. South Africa has had many hardships that brought division to the foundations of its community. When citizens struggle to develop a sense of belonging due to such divisions, it has an impact on their identity, role and participation in the community. The study asserts that schools are able to provide critical citizenship learning experiences, and that Visual Arts facilitates this exceptionally well. The study employed participatory action research (PAR) in which three schools participated. The research was designed to help learners and educators experience critical citizenship education. Learners investigated critical citizenship and social justice by brainstorming conceptions of citizenship in the local, national and global community and completed research independently to further their engagement. Learners underwent an embodied creative process and produced artwork to create a message or to comment on their community. Reflection occurred at the end of the PAR project when the educators were interviewed to give feedback and reflect on the learning experience. The participating learners potentially benefitted from the research by acquiring critical citizenship skills. The hope is that they will apply these skills in more subject disciplines, in broader contexts beyond school, and that they will also transfer them to future situations and generations. The educators benefitted by learning how to incorporate critical citizenship into their teaching and to become more aware of the impact Visual Arts can have on learners’ educational journey. Primary school learners’ conceptions of citizenship initially focused on team sports, animal cruelty, drinking and driving, people in service of the community (firefighters, police officers, doctors and nurses), violence and fighting, helping others, homelessness, kidnapping, loud neighbours, pollution and littering, stealing, hijacking, break-ins, watering trees and plants, rudeness, kindness, protecting the ocean, honesty, listening to parents and educators, donating money and food, criminals in prisons, deforestation and loadshedding. At the end of the project, conceptions of critical citizenship deepened to include child abuse and kidnapping, bullying, active participation in the community (working together to solve problems, helping one another, uplifting the community, assisting people with disabilities), environmental issues caused by irresponsible behaviour (climate change, overfishing, deforestation, littering, arson), unemployment and homelessness, animal cruelty and abuse, negative behaviour (being disrespectful, selfishness, affecting others with our bad choices), positive behaviour (kindness, good moral values, forgiveness, being considerate, honesty), crime (stealing, robbing, home break-ins, drunk driving), racism and prejudice, a lack of effective communication and connection (not listening or being distracted by devices), loadshedding, corruption and poverty. The impact of the research is a contribution to the literature on what learners grasp as essential issues in citizenship in contemporary South Africa and to show the application of critical citizenship education in Visual Arts.Doctora
Transforming residential education through care : student experiences at a South African University during COVID-19
Get PDFThe original publication is available at https://www.tandfonline.com/This article challenges dominant framings of COVID-19 education as either a moment of crisis or an idealised opportunity to reimagine learning. Instead, it offers a counter-narrative grounded in an ethnographic study of a Residential and Educational Support Programme (RESP) at Stellenbosch University – a historically white institution undergoing transformation. Launched during the pandemic, one residence space was configured into a site of care, co-learning, and humanising pedagogy. Centring the voices of predominantly Black women students, the article reveals how participants critically engaged with their identities, navigated systemic inequalities, and cultivated a sense of belonging within a historically exclusionary institutional culture. These experiences demonstrate that meaningful transformation arises from embodied relationships, solidarity, and collective empowerment. The article argues for contextually rooted, ethically driven residential education as a transformative force. In doing so, it contributes to global conversations on inclusive higher education and offers a model for reimagining residential learning beyond the pandemic.https://www.tandfonline.com/doi/full/10.1080/03057925.2025.2571473Publisher's versio
Modelling Global Arbovirus Disease Ecology, Transmission and Importation Risks
No full textThesis (PhD)--Stellenbosch University, 2025.Poongavanan, J. 2025. Modelling Global Arbovirus Disease Ecology, Transmission and Importation Risks. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/4c519006-d442-46dc-9b75-7ae0d8e87709The global burden of arboviruses, including dengue virus (DENV) and Oropouche virus (OROV), which continue to re-emerge, could be exacerbated by climate change, urbanisation, and international mobility. However, surveillance limitations and spatial heterogeneity in data availability, particularly across Africa, have hindered accurate risk estimations and the development of effective control strategies. This thesis presents spatially explicit models that address key gaps in risk estimation across different stages of arbovirus emergence. Specifically, it investigates: (i) how to identify African regions most at risk of dengue introduction using international air travel data; (ii) how to estimate fine-scale dengue incidence in the absence of granular case data; (iii) how pseudo-absence sampling design influences the predictive performance of ecological niche models for emerging arboviruses; and (iv) what spatial and ecological factors shape the transmission risk and dispersal of OROV within South America and Brazil.
In Chapter 2, we aim to identify African regions most at risk of dengue introduction using air travel data and local transmission suitability estimates. We develop a risk model integrating flight volumes with transmission potential and population density to identify areas where importation risk overlaps with conditions for local transmission, which can inform targeted surveillance. Chapter 3 addresses the challenge of generating fine-scale dengue incidence estimates in the absence of granular case data. We apply a disaggregation regression model to subnational dengue case data from Latin America and project it to Africa to produce high-resolution incidence estimates. We then compare these predictions with available national case reports and assess how they align with other existing dengue risk indicators, including environmental and vector suitability maps. In Chapter 4, we evaluate how five pseudo-absence sampling strategies influence the performance of ecological niche models for OROV. Building on this, we generate refined predictions of environmental suitability across the Americas, explore seasonal patterns of OROV transmission in Brazil, and assess areas of spatial overlap between the virus and its primary vector, Culicoides paraensis to identify zones of potential co-suitability and expansion risk. Finally, Chapter 5 explores how OROV has spread through Brazil by combining phylogeographic reconstruction with environmental and landscape modeling. We trace long-distance viral dispersal events and identify ecological features that shape OROV’s expansion.
Together, these studies demonstrate the value of combining diverse and adaptable modeling approaches to improve arboviral risk prediction. By integrating ecological, epidemiological, and mobility data, the thesis produces high-resolution, spatially explicit outputs that offer more accurate and context-sensitive estimates across different stages of disease emergence. The work contributes novel methods and practical tools that enhance the precision, versatility, and public health relevance of arboviral risk mapping.Doctora
The 15-minute city: An Accessibility Study of the City of Cape Town
Get PDFThesis (MCom)--Stellenbosch University, 2025.Van Greuning, W. 2025. The 15-minute city: An Accessibility Study of the City of Cape Town. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/58fc6208-ddbc-430d-a56b-bf3b6ff2cf2dThe 15-minute city concept has gained significant global attention as an urban planning strategy. At its core, the concept ensures that residents can access essential services and amenities within a 15-minute commute from their homes. However the feasibility of the 15-minute city concept within in diverse urban contexts, particularly within Africa, remains underexplored.
This dissertation examines the applicability of the 15-minute city model in Cape Town, South Africa, assessing both its potential benefits and limitations. A mixed methodological approach was used, including a survey of town and city planners to gather professional insights as well as a spatial and quantitative analyses to evaluate the urban accessibility and transport-related impacts.
The survey results indicate that planners are generally optimistic about the benefits of the concept, particularly regarding walkability, reduced congestion, and environmental improvements. However, concerns were raised about governance challenges, infrastructure short falls, and socio-economic inequalities that could hinder its implementation. The spatial analysis found that while amenities are well-distributed in central areas, low-income and peripheral neighbourhoods face accessibility deficits. The quantitative analysis suggest that a 10% shift from private car use to walking and/or cycling could lead to a reduction of 85,586 vehicles, cutting 190,002 metric tonnes of greenhouse gas emissions, with a associated social value of R36.10 million annually.
The study acknowledges limitations, such as the availability of urban mobility data, the small sample size and the need to extend the survey to users and not just to urban planners. These limitations my affect some of the validity of some results.
From a practical standpoint, the findings highlight the need for integrated urban planning, multi-sectoral collaboration, and targeted investment in underserved areas to improve accessibility and equity. Policymakers, urban planners, and stakeholders must work together to bridge infrastructure gaps and promote non-motorised transport that supports sustainable urban transformation in South African cities.Master
Beyond planning: the dynamics of living in the new public housing settlement of Forest Village on the Cape Flats
Get PDFThesis (MA)--Stellenbosch University, 2025.Salie, M. A. 2025. Beyond planning: the dynamics of living in the new public housing settlement of Forest Village on the Cape Flats. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/735c3ddb-7073-4d60-adc6-ef9baeed9c6bThis research is focused on Forest Village; a recently built government housing settlement located on the periphery of Cape Town. It was built in 2016, after more than two decades of post-apartheid housing policy, and residents moved into the settlement over the subsequent eight years after different phases of the construction were completed. My study considers whether the settlement represents an improvement on previous government housing projects by describing the challenges the settlement has faced, from its planning and design to the experience of living in the settlement. While recognising the continued need to provide housing for many of its poorest residents, the study suggests that its location, construction administration and building quality continue to confront recipients of government houses. Moreover, I show that even for those who do manage to receive houses and achieve a measure of security, social cohesion and community do not occur organically, and the difficulties of unemployment, crime and racism confront new residents of the area. I argue ultimately that although policy has made significant improvements, the question of location remains a serious difficulty and “community building” cannot be taken for granted in a society as socially fractured and materially unequal as post-apartheid South Africa.Master
Development of a Wayside Monitoring System for Rail Wheel Defect Detection Using Thermography and Dynamic Measurements
No full textThesis (MEng)--Stellenbosch University, 2025.Lubbe, E. 2025. Development of a Wayside Monitoring System for Rail Wheel Defect Detection Using Thermography and Dynamic Measurements. Unpublished masters thesis. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/87b5c51d-bf32-47d9-aefb-b672fbad57cbThis thesis develops and evaluates a wayside monitoring system for rail-wheel tread defect detection using thermography and conventional dynamic measurements (rail-mounted accelerometer). The work had two main objectives: (1) to design and validate a thermography wayside monitoring system capable of in-situ detection and geometric characterisation of wheel-tread defects under depot conditions, and (2) to benchmark thermography against an accelerometer-based reference to quantify detection performance, localisation, speed sensitivity, environmental robustness, processing time and cost. An experimental campaign was conducted on the X’Trapolis Mega train sets within a depot setting. Based on an initial thermography study, it was observed that wheel tread defects produce a thermal contrast that can be extracted. This observation informed the development of a defect length estimation method, which determines the defect length and compares it with a manual inspection measurement to assess accuracy. The thermography wayside system comprises a strategically positioned thermal camera that captures approximately one and a half revolutions of the wheel. Furthermore, camera calibration was conducted to correct lens distortions and generate a spatial map of the visible rail section. This map enables the system to associate defect locations with the closest calibration reference point, facilitating the application of the length estimation algorithm through back-projection of the points. A conventional wayside monitoring system was implemented utilising an accelerometer-based approach. The system consists of five rail-foot-mounted uniaxial sensors complemented by two-point lasers for axle counting and timing. The signals were analysed in the time domain through the use of statistical features, including Peak-to-Peak, root mean square, kurtosis, and crest factor, which were integrated into a joint metric for automated flagging. The key findings demonstrate complementary strengths. Both methods achieve high detection accuracy at depot speed (3 km/h). The accelerometer joint metric delivered F1-scores of 0.96 (3 km/h), 1.00 (10 km/h), and 0.96 (20 km/h). In comparison, thermography achieved perfect detection on the tested set at 3 km/h, revealing several surface defects missed in manual inspection. Thermographic length estimation produced typical errors of ±1.5 mm for defects less than 100 mm at speeds up to 10 km/h. Still, its performance degraded (mean error ≈ 8.7%) at 20 km/h due to motion blur and reprojection limitations. Processing and cost trade-offs are notable: accelerometers are rapid (≈ 75 ms per wheel), robust to ambient conditions, and cost-effective (≈ ZAR 264,790), whereas the thermography package is more ex-pensive (≈ ZAR 1.6 million), slower under the current semi-automated workflow (≈ 10 s per wheel), but uniquely provides direct visual severity measures and the ability to localise multiple defects per wheel. The thesis concludes that thermography is a feasible technique for wayside monitoring, as it enables the identification of wheel tread defects, which can be evaluated in accordance with regulatory standards. Furthermore, a hybrid approach is suggested, utilising accelerometers for continuous, automated screening and triggering thermographic inspections for quantitative severity evaluation and geometric analysis. To enhance readiness for field deployment, the study recommends automating thermal defect localisation, assessing more cost-effective cameras, and improving extrinsic calibration rigs to augment throughput and measurement capabilities.Master
The National Health Dialogue: An Ethical Evaluation of the National Health Insurance Bill
Get PDFThesis (PhD)--Stellenbosch University, 2025.Lotz, J. W. 2025. The National Health Dialogue: An Ethical Evaluation of the National Health Insurance Bill. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/9b5e09b4-df22-46cc-9eac-8134e74768a7The just allocation of scarce healthcare resources and the social determinants of health in society requires an acceptable theory of distributive justice. John Rawls is well-known for his theory of justice as fairness, but never considered the application of his theory to the realm of healthcare provision. Norman Daniels took on this task, and made use of Rawlsian theory to justify the special moral value of health. He insists that meeting the health needs of individuals makes an essential contribution to ensuring that fair equality of opportunity is secured, but that the right to healthcare must be conceptualised within the context of resource limitations. South Africans face unique challenges in reforming the healthcare system. Health demands outstrip available resources, and access to healthcare is highly unequal. In response to this, the government intends to introduce a National Health Insurance [NHI], which is one of the most consequential and wide-ranging policy propositions of the South African democratic era. The proposal is that the NHI will merge the private and public healthcare systems, and will, through the health minister’s office, decide which public and private providers will be contracted to deliver services to all citizens. The claim is that this will uphold an unfettered positive right to health, based on the notion of universal human dignity. The call for universal access to the maximum level healthcare as a human right is, however, unattainable in a developing nation’s resource-restricted environment. Reality dictates that universal healthcare access will remain, for the foreseeable future, a distant ideal. In seeking a pragmatic alternative, this dissertation will argue that a moderate egalitarian alternative which promotes equal access to a basic minimum of healthcare, and based on the work of Rawls and Daniels, is preferable to the NHI proposal.Doctora
Conversion of sugar cane A-molasses and lignocellulosic biomass to value-added products: Techno-economics and greenhouse gas emissions
Get PDFThesis (PhD)--Stellenbosch University, 2025.Phasha, M. J. 2025. Conversion of sugar cane A-molasses and lignocellulosic biomass to value-added products: Techno-economics and greenhouse gas emissions. Unpublished doctoral dissertation. Stellenbosch: Stellenbosch University [online]. Available: https://scholar.sun.ac.za/items/a2287532-dfd6-4ab5-873d-b30600ce5003South Africa has the largest sugarcane production on the African continent, at approximately 18 million tons annually. Currently, biomass generated from sugarcane processing is used to meet the internal energy demands of the sugar mills, even though it can be repurposed for high-value biochemicals and fuel production. Using residues from sugar production, i.e., lignocellulose and molasses, as feedstocks can assist in diversifying sugarcane industries' product portfolios by incorporating desired biorefineries to improve resilience against market fluctuations and other related process inputs. Furthermore, the shift towards biochemicals and fuels may help alleviate greenhouse gas emissions, contributing to the achievement of the Sustainable Development Goals (SDGs), particularly SDGs 8, 9, 12, 13, and 17. This study aimed to determine the most technically feasible, economically viable, and low-GHG-emission process configurations for producing bio-based chemicals from a selected shortlist of products that compete for the limited sugarcane feedstocks within the energy self-sufficient biorefinery concept. Ethyl lactate, muconic acid, ethyl acetate, and butyric acid were selected as potential products due to their high market demand, relatively high market prices, and a wide range of industrial applications.
The first objective was to find the best process configuration for producing ethyl lactate (EL) in a sugarcane biorefinery that is energy self-sufficient, based on the lactic acid (LA) and ethanol (EtOH) production as precursors using 1G and 1G2G feedstocks. The study evaluated the fermentation chemistry of LA, separation methods, neutralization agents, and the recovery of by-products to optimize EL production while minimizing costs and greenhouse gas (GHG) emissions. It found that using Mg(OH)2 based on the Corbion ™ process with reactive esterification distillation (RED) reduced operational costs by 38% and energy demands by 15%, achieving a competitive minimum selling price (MSP) of 1850/t. The process configuration generated 14 t/h of EL with specific energy demands of 21.25 kWh/kg and GHG emissions of 1.36 kg CO2 eq/kg, resulting in a 72% reduction in emissions compared to fossil fuels. However, the 1G2G configurations were deemed technically infeasible due to high energy demands, so their economic viability and GHG emissions were not assessed.
The second objective was to design and develop conceptual bio-refinery process flowsheets for the production of muconic acid (ccMA) and butyric acid (BA) using 1G (molasses-only) and mixed 1G & 2G sugarcane feedstocks in biorefineries annexed to an existing sugarcane mill. Following the technical infeasibility of 1G2G EL processes/biorefineries in Objective One, where economics and GHG emission evaluations were omitted, the extent of possible gains from 1G2G feedstock integration is evaluated in the ccMA and BA scenarios. Since the muconic acid-producing microbe, P. pudita, can break down solubilized lignin, which makes up over 20% of the 2G sugarcane feedstock, the potential of using solubilized lignin for ccMA production was evaluated in a scenario involving only 1G2G ccMA. Additionally, the co-production of ccMA from solubilised lignin and BA from 1G2G sugars was considered a multi-component process. The recovery of hydrogen as a by-product was evaluated to determine its impact on the MSP.
Following the results of using alternative regenerable fermentation neutralisation agents in the first objective, the BA scenarios also investigated the use of alternative neutralisation agents. This resulted in the BA production scenarios being generally more profitable than the ccMA scenarios, with the best scenario achieving a minimum selling price (MSP) of 1700/t. In contrast, the ccMA scenario achieved an MSP of $2364/t despite muconic acid being the least energy-intensive scenario (6.4 kWh/kg), but this was not market competitive as the MSP was about 40% above the market prices. In the 1G2G ccMA scenario, solubilized lignin enabled maximum biomass utilization, improving profitability but increasing GHG emissions (1.61 kg CO2 eq/kg). Using alternative neutralisation agents improved the viability of the 1G BA scenarios.
The third objective was to produce ethyl acetate (EA) through catalytic dehydrogenation (CDH) of EtOH, as well as via Fischer esterification (FE) of EtOH with acetic acid (AA), which was investigated. Pressure swing distillation (PSD) and extractive distillation (ED) methods were also investigated for the recovery and purification of EA. The biorefineries were annexed to an existing sugarcane mill and utilised 1G-only or 1G2G sugarcane feedstocks. Following the results of using regenerable neutralisation agents in the previous chapters, the concept was also applied to EA. The impact of selling by-products (such as hydrogen and butyric acid) on the MSP was evaluated. Based on data reported in the literature, the simulations were conducted using Aspen Plus®. The best 1G scenario produced EA at 9 t/h, and the respective specific energy demands of 7.60 kWh/kg_EA and GHG emission reduction of 1.07 kg CO2 eq/kg were achieved.
The fourth objective was to benchmark the biochemicals against one another and select biochemicals investigated previously to determine the best chemical(s) for recommendation as the preferred to be produced from the limited sugarcane feedstocks. The comparison was based on MSPs, market size, energy efficiency, and GHG emissions as primary key performance indicators (KPIs). It was found that producing butyric acid from limited feedstock was best, owing to its relatively high energy efficiency, high GHG emission reduction, and competitive MSP.Doctora
Correlates of incident hypocalcemia amongst trauma patients in the Western Cape of South Africa : a secondary analysis of the epidemiology and outcomes of prolonged trauma care (EpiC) study
Get PDFThe original publication is available: https://link.springer.com/Background: Derangements in ionized calcium are common following trauma, with prior research describing an association between hypocalcemia and adverse outcomes such as mortality, coagulopathy severity, and transfusion requirement. The present study evaluates clinical characteristics of patients presenting to emergency care with ionized calcium derangements following severe trauma in a low-resource practice setting. Methods: Patients presenting to emergency care throughout the Western Cape of South Africa following severe traumatic injury (excluding patients with severe traumatic brain injury) for whom an ionized calcium level was measured are included. Patients were stratified according to initial ionized calcium, and characteristics of the different strata (demographics, injury characteristics, and initial serum biomarkers) were compared. Linear and quadratic regression was used to evaluate the relationship between initial ionized calcium and selected laboratory markers such as hemoglobin, lactate, venous pH, and platelets. Results: 1989 subjects were included. The median initial ionized calcium was 1.14 mmol/L (IQR: 1.09–1.19 mmol/L). 51% of patients were hypocalcemic ( 1.29 mmol/L) on presentation. Differences were observed between ionized calcium strata with respect to age (p < 0.01), injury body region (p = 0.02), maximum abbreviated injury scale (AIS) score (p = 0.03), and shock index (p = 0.05). There was a statistically significant relationship between initial ionized calcium and both platelets (p < 0.01) and hemoglobin (p = 0.03) when treating ionized calcium as a quadratic (U-shaped) variable. Conclusions: Derangements in ionized calcium following acute trauma are associated with injury severity (as defined by maximum AIS score) and injury body region, as well as a subset of other laboratory values, including platelet count and hemoglobin. It is notable that the relationship between these variables was parabolic, suggesting that both extremes of ionized calcium derangements are associated with derangements in other serum markers.Publisher's versio