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Trends in antibiotic use and treatment failure in community-acquired uncomplicated urinary tract infections treated by family physicians in British Columbia
No full textIntroduction: In the last decade, the prevalence of antimicrobial resistance (AMR) among uropathogens has risen worldwide. Uncomplicated urinary tract infections (uUTIs) in females are one of the most common reasons for antibiotic prescribing by family physicians (FPs) in Canada. The treatment for this infection is mainly empirical. Considering the impact of inappropriate antibiotic prescription on AMR, it is important to examine the trends of antibiotic use, assess the characteristics of the population, and evaluate treatment failure (TF) while considering local resistance rates in British Columbia (BC). This thesis examined the trends of antibiotic use for uUTI by FPs and TF in community-acquired uUTIs in the female population of BC.
Methods: A retrospective cohort study was conducted using linked administrative databases to identify uUTIs episodes in the female population of BC from 2012 to 2023. Antibiotic switch, kidney infection, and sepsis were used as a proxy for TF during the follow-up period of 28 days. Associations between year (change per year), therapy line, and time to TF were estimated using Cox regression analysis. Poisson regression with robust standard errors was used to assess the appropriateness of antibiotic prescription by therapy line over time.
Results: Among 1,934,014 uUTI episodes in the female population, 9.4% experienced TF. The rate of physician-treated uUTI episodes showed a downward trend over the study period, with an increased use in guideline concordant first-line therapy. Patients who were prescribed alternative or non-recommended antibiotics were more likely to develop kidney infection and sepsis and those who received non-recommended antibiotics were more likely to have an antibiotic switch during the episode.
Conclusion: The proportion of physician-managed uUTI episodes that led to TF has remained stable over the study period. A downward trend in physician-managed uUTI episodes was observed and may relate to a shift to pharmacy and nurse prescribing. First-line antimicrobials have been consistently the preferred choice of therapy among FPs. Further studies are needed to assess other healthcare providers’ prescription behaviour.Medicine, Faculty ofPopulation and Public Health (SPPH), School ofGraduat
The effects of semaglutide on adolescent male and female C57BL6/J mice
No full textGlucagon-like peptide-1 (GLP-1) is an endogenously produced incretin hormone that influences glucose regulation and satiety by acting upon GLP-1 receptors (GLP-1r) throughout the body. While semaglutide, a weekly injectable GLP-1r agonist medication, was originally developed for the treatment of type 2 diabetes, it was also found to cause robust weight loss. Clinical trials have demonstrated body weight loss of ~15% in adults with obesity, alongside losses of both fat and lean mass. Skeletal muscle constitutes ~50% of lean mass, contributes to ~25% resting energy expenditure, and is the primary sink for insulin mediated glucose disposal. Given the importance of skeletal muscle to overall health, the loss of this tissue could have unintended negative consequences. Increasingly younger individuals are being prescribed semaglutide and given that adolescence is a critical period of musculoskeletal development, it is important to determine the impact of GLP1r agonists on muscle and bone health in this age group. The aim of my thesis was to investigate the effects of semaglutide on visceral, muscular, and skeletal tissues in adolescent mice. I hypothesized that semaglutide would attenuate weight gain and cause reductions in mass and function for skeletal muscle and bone in adolescent mice with obesity. Adolescent male and female C57BL6/J mice (n=~20 per group) were weaned at 4 weeks old and placed on a high fat diet for ~4 weeks (HFD, 60% fat, 20% carbohydrate, 20% protein), then assigned to sex and weight-matched groups: 1) HFD, 2) HFD + Semaglutide. Mice were subcutaneously injected daily, for 3 weeks, at the start of dark phase with 10nmol/kg vehicle or semaglutide, with food intake and body weight measured daily. During the final week of treatment, an oral glucose tolerance test, metabolic caging, in vivo body composition analysis, grip strength testing, and tissue collection occurred. Visceral and subcutaneous fat were reduced with semaglutide treatment. There were no significant reductions in lean mass or most skeletal muscles, however grip strength was reduced as was femur weight and strength. Our results suggest that semaglutide, while preventing weight gain, has deleterious effects on skeletal muscle function and bone mass and function in adolescent mice fed a HFD.Education, Faculty ofKinesiology, School ofGraduat
The origins of communal roosting behaviour in birds
No full textCommunal roosting is a form of social behaviour exhibited by hundreds of species of birds where unrelated individuals spend the resting time together. Different hypotheses have been proposed to explain the origins of this behaviour, including predator avoidance, thermal regulation, and increased foraging efficiency through the Information Center Hypothesis (ICH) which suggests information transfer at roost sites. To test for potential evolutionary drivers of communal roosting, I first compiled ecological data from all landbirds as this behaviour has been more consistently studied on landbirds. I collected communal roosting information from online databases and published literature, and classified communal roosting behaviour as present (1) or absent (0). I then used body mass (kg), trophic guild, Hand-wing Index (HWI) and brain to body size ratio as potential predictor variables and evolutionary relatedness using phylogenetic trees from VertLife, a website of resolved phylogenies for all extant species. I fit generalized linear models using biological variables as predictors and communal roosting behaviour as a response after accounting for phylogeny. I then performed model comparison between the null model with phylogeny only and the full model to test whether CR can be explained with the aforementioned variables. My results show that this behaviour is positively correlated to body mass and HWI independent of phylogeny, and is more persistent in scavengers than any other trophic guild. My findings expand on Beauchamp’s study, and support that communal roosting cannot be explained through phylogeny only. I use these results to highlight the importance of communal roosting sites for birds, with particular emphasis on obligate scavengers, and discuss the implications of foraging efficiency from the lens of the Information Center Hypothesis.Science, Irving K. Barber Faculty of (Okanagan)Biology, Department of (Okanagan)Graduat
Decision support methods for alarm management in industrial automation systems
No full textThe full abstract for this thesis is available in the body of the thesis, and will be available when the embargo expires.Applied Science, Faculty ofEngineering, School of (Okanagan)Graduat
Data-driven recalibration methodology for spatially transferring the vehicle ownership module of an agent-based integrated urban model
No full textSTELARS is a large-scale Integrated Urban Model that simulates land use, vehicle ownership, and transportation decisions within an agent-based framework. Vehicle ownership in STELARS is conceptualized as a two-stage process involving vehicle transaction and type choice, represented by six interrelated micro-models. Traditional model updating approaches in enhancing transferability have largely focused on recalibrating a single model at a time and have not been designed to handle large, interdependent systems composed of multiple micro-models. This limitation hinders the spatial transferability of such complex frameworks when applied to new geographic regions with different socioeconomic and behavioural characteristics. To address this challenge, this study proposes a data-driven recalibration framework that enables updating of all micro-models within the vehicle ownership module, thereby enhancing spatial transferability while preserving structural consistency. The proposed framework employs a Steady-State Elitist Genetic Algorithm assisted by a Random Forest surrogate model to determine recalibrated parameter sets. For the recalibration, initial parameter sets were generated using Latin Hypercube Sampling within ±100 percent of original calibrated values, and Mean Absolute Error was used as the objective function to minimize. The recalibration was conducted to transfer the vehicle ownership module from the Okanagan Region to the Greater Vancouver Area, British Columbia, utilizing aggregate data sources. The proposed strategy yielded promising results: the simulated household vehicle ownership distribution in the Greater Vancouver Area matched the observed values within a 4 percent discrepancy range. Additionally, 62 percent of the parameters in the vehicle type models after recalibration remained within the ±75 percent range of their original estimates, indicating that most behavioural patterns observed in the Okanagan model were largely retained in the transferred context. Where deviations did occur, they reflected behavioural and contextual differences between the regions. This stability across regions demonstrates the robustness of the original model specification and suggests that while regional differences exist, the overall behavioural structure of vehicle ownership decisions remains transferable. Overall, the proposed framework provides a scalable, resource-efficient, and data-driven approach for transferring complex urban models to data-scarce contexts, thereby broadening their applicability for policy and planning analyses.Applied Science, Faculty ofEngineering, School of (Okanagan)Graduat
Numerical bifurcation study of a mass conserved reaction-diffusion model for actin waves : unravelling motility modes of cells
No full textCell motility is a necessary process in many bodily functions, including wound healing. This motility is induced by a protein called actin, which forms filaments near the surface of cells. Regulators of filamentous actin formation include GTPases that act as molecular switches, cycling between active and inactive forms. Together, these proteins form complex spatio-temporal patterns (denoted “actin waves”) that govern cell motility. Recent experiments show that stationary patterns that induce directed cell motion and wave patterns that induce cell turning or ruffling can coexist in cells. This motivates the main question of this thesis: What are the underlying mechanisms that govern the coexistence of polar and wave patterns? To address this question, I derive a simple model for actin waves consisting of three partial differential equations for a mass-conserved active and inactive GTPase that promotes the formation of actin filaments (F-actin). The F-actin then feeds back onto the GTPase by increasing the inactivation rate. The simple model with its geometry (1D periodic cell perimeter) allows for the use of bifurcation analysis to study how patterns emerge, interact, coexist, and affect each other’s stability. This thesis focuses mostly on the long wavelength (LW) and finite-wavenumber Hopf (WB) bifurcations that lead to stationary and travelling wave solutions, respectively. I address the coexistence of these patterns by investigating the steady state solutions that emerge from two codimension-2 LW/WB instabilities. Only one codimension-2
instability leads to coexistence of polar and travelling wave solutions, and the analysis suggests that the initial bifurcating solutions need to form holes (i.e., troughs) instead of peaks. I also describe a rich structure of propagating highly localized patterns, namely, travelling fronts and excitable pulses. I show that mass conservation affects the types of patterns that emerge and discuss its effect on pattern formation. I supplement the bifurcation analysis with time-dependent simulations in one and two spatial dimensions, and simulations of motile cells to demonstrate the robustness and transient interactions between the coexisting states. The bifurcation analysis and time-dependent simulations show that the negative feedback from F-actin onto the GTPase affects the types of patterns that emerge.Science, Faculty ofMathematics, Department ofGraduat
Sampling in hip-hop : an analysis of aesthetics of community and intergenerational lineages
No full textSampling is quintessential to the genre of hip-hop. From its inception in the early 1970s to the bedroom producers of the present day, DJs and producers alike have used this musical technique to turn already existing music into something different. The source of sampled music is often rooted in inspiration, but what draws these inspirations varies. For some, it might be an album cover, catchy drum break, or a record that was played around the house. Using Christopher Small’s “musicking” framework, this thesis explores the lineages of sampling and the intergenerational bridges that form between hip-hop and the genres that preceded it. Chapter 2 analyzes technology and its contributions to music, sampling, and the way the hip-hop community engages with sampling through online spaces. Chapter 3 analyzes how sampling creates lineages and connects community through intergenerational relationships. Chapter 4 explores legality, racism, and the ways that it affects sampling and how we engage with it, while Chapter 5 serves as a conclusion. Throughout this thesis I explore personal connections with the music through an autoethnographic approach.Arts, Faculty ofMusic, School ofGraduat
A capacitively coupled contactless conductivity detector with micellar electrokinetic chromatography for the detection of ethanol in milk
No full textThe consumption of alcohol during breastfeeding can lead to ethanol-contaminated breastmilk, and when consumed by infants, can cause reduced intake of milk and improper development. Health organizations provide oversimplified and vague guidelines to breastfeeding women regarding alcohol consumption. Commercialized products exist to enumerate the presence of ethanol in breastmilk but are underdeveloped. Laboratory separation and detection methods offer accurate and sensitive results, but require off-site testing, expensive equipment, and skilled personnel. This thesis addresses the lack of point-of-care sensors to detect ethanol in breastmilk by developing a microfluidic sensor that uses capacitively coupled contactless conductivity detection and micellar electrokinetic chromatography to separate and detect ethanol in bovine skim milk as a preliminary step towards detecting ethanol in breastmilk. A custom-built capacitively coupled contactless conductivity microfluidic sensor is developed and the effects of shielding techniques and electrode spacing against the signal-to-noise ratio are optimized. The optimal results are achieved with a ground line shielding technique and 500 μm electrode spacing. For ethanol separation, micellar electrokinetic chromatography, a mode of microchip capillary electrophoresis, is employed with a 20 mM citrate, 30 mM sodium dodecyl sulfate, and 4.3% 0.1 M sodium hydroxide (v/v) background electrolyte solution. Ethanol is detected in three Canadian milk brands in five minutes average and a limit of detection of 0.97% (v/v) is achieved. The developed microfluidic sensor serves as a promising approach to the on-site testing of ethanol in breastmilk using laboratory grade separation and detection methods on a miniaturized scale.Applied Science, Faculty ofEngineering, School of (Okanagan)Graduat
Understanding collaborative landscape governance to inform integrated landscape approaches : evidence from Ghana and Zambia
No full textThere is growing recognition global challenges such as biodiversity loss, climate change, food insecurity, and poverty are interconnected issues. This signals the need for a shift from conventional sectorial management to integrated solutions, and integrated landscape approaches (ILAs) are an opportunity in this regard. ILAs are broadly defined as long-term participatory processes for reconciling competing land uses for improved socio-economic and environmental outcomes. ILAs are predicated on the assumption collaboration across scales, sectors, and diverse social groups will occur to achieve more equitable and sustainable landscape governance. Yet, there is little evidence showing if, how, and when collaborative landscape governance occurs. This study explores the barriers and opportunities of collaborative landscape governance in Kalomo District, Zambia and Ghana’s Western Wildlife Corridor. The objective of this dissertation was to a) characterize landscape priorities across both landscapes b) understand perceptions of decision-making power over landscape priorities and c) the expectations and experiences of collaboration held by landscape actors. Primary data collection took place from April-July 2022 in Zambia and February-late April 2023 in Ghana. Findings from 78 semi-structured interviews and 10 focus group discussions revealed landscape actors share an overarching desire for a resilient landscape that sustains local livelihoods. However, a deeper analysis of landscape priorities and perceptions of decision-making power revealed where seemingly aligned priorities diverged. Participant experiences with collaborative landscape governance showed the desire for improved collaboration exists, but the efficacy of collaborative processes is often tied to the availability of resources to support the long-term participation needed to build trust and foster inclusion. ILAs show potential to enhance collaboration and leverage collective power to meet shared objectives, but long-term support mechanisms are needed to sustain these processes.Forestry, Faculty ofGraduat
In-flight vitrification of granite, shale, and basalt for scalable glassy supplementary cementitious materials
No full textPartial replacement of cement with supplementary cementitious materials (SCMs) remains one of the most effective strategies for reducing concrete's greenhouse gas emissions through clinker factor reduction. However, conventional SCM sources are increasingly constrained: coal fly ash supplies are declining, natural pozzolan deposits are geographically limited, and blast-furnace slag is fully utilized. This dissertation presents in-flight vitrification as a novel technique to transform abundant, otherwise unreactive silicate rocks into SCMs.
Three archetype feedstocks representing globally abundant rock types (granite, shale, and basalt) were milled and thermally activated by in-flight vitrification, producing glassy microspheroidal powders. Comprehensive characterization including automated SEM-EDS, XRD, XRF, and standardized reactivity tests demonstrated that vitrification increased pozzolanic reactivity approximately five-fold compared to unvitrified controls. All vitrified SCMs exceeded ASTM C618 requirements, achieving >100% strength activity index at 28 days, with R³ heat release consistent with commercial siliceous pozzolan. Notably, vitrification successfully activated illitic shale that resisted activation by conventional calcination, expanding the palette of possible feedstocks that can be activated.
Concrete testing with 20% cement replacement matched or exceeded 100% Portland cement control strength after 28 days. The microspheroidal morphology reduced water demand compared to controls, a practical advantage over other SCM manufacturing techniques.
Automated SEM-EDS revealed that vitrified particles are primarily discrete mineral-derived glasses rather than homogenized compositions, which may guide future reactivity modeling. Particle circularity emerged as a proxy for glass content in vitrified SCM, with strong correlation (R=-0.89) between higher circularity particles having lower crystallinity.
Theoretical estimates suggest process energy requirements could be 1.23-2.30 GJ/tonne when scaled and optimized, comparable to flash calcination and with minimal yield loss (<4%) versus (40% for) clinker production. Field demonstrations totaling 300 cubic yards of concrete validated vitrified granite SCM in commercial applications, achieving performance equivalent to high-quality fly ash.
The abundance of suitable silicate feedstocks worldwide includes quarry overburden and aggregates already mined almost everywhere concrete is sold. Therefore, in-flight vitrification, needing mainly just rock and heat energy as inputs, could democratize future production of low-CO₂ SCM by converting the most common silicate rocks into microspheroidal pozzolans.Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat