Graduate Theses & Dissertations

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Soil mineralizable nitrogen as an indicator of soil nitrogen supply for grain corn in southwestern Ontario
Soil mineralizable nitrogen (N) is the main component of soil N supply in humid temperate regions and should be considered in N fertilizer recommendations. The objectives of this study were to determine the potentially mineralizable N parameters, and improve N fertilizer recommendations by evaluating a suite of soil N tests in southwestern Ontario. The study was conducted over the 2013 and 2014 growing seasons using 19 field sites across southwestern Ontario. The average potentially mineralizable N (N0) and readily mineralizable N (Pool I) were 147 mg kg-1 and 42 mg kg-1, respectively. Pool I was the only soil N test that successfully predicted RY in 2013. The PPNT and water soluble N (WSN) concentration (0-30cm depth) at planting were the best predictors of fertilizer N requirement when combing data from 2013 and 2014. When soils were categorized based on soil texture, the relationships also improved. Our findings suggest that N fertilizer recommendations for grain corn can be improved, however, further field validations are required. Author Keywords: corn, nitrogen, nitrogen mineralization, soil nitrogen supply, soil N test, southwestern Ontario
silicon sol-gel approach to the development of forensic blood substitutes
The research and development of synthetic blood substitutes is a reported need within the forensic community. This work contributes to the growing body of knowledge in bloodstain pattern analysis by offering a materials science approach to designing, producing and testing synthetic forensic blood substitutes. A key deliverable from this research is the creation of a robust silicon-based material using the solution-gelation technique that has been validated for controlled passive drip and spatter simulation. The work investigates the physical properties (viscosity, surface tension and density) of forensic blood substitute formulations and describes the similarity in the spreading dynamics of the optimized material to whole human blood. It then explores how blood and other fluids behave in impact simulation using high-speed video analysis and supports the use of the optimized material for spatter simulation. Finally, the work highlights the practical value of the material as an educational tool for both basic and advanced bloodstain experimentation and training. Author Keywords: bloodstain pattern analysis, forensic blood substitutes, high-speed video analysis, silicon solution-gelation chemistry, thin-film deposition, training and education
Regional Assessment of Soil Calcium Weathering Rates and the Factors that Influence Lake Calcium in the Muskoka River Catchment, Central Ontario
(MRC) in central Ontario was carried out to determine the range and spatial distribution of soil Ca weathering rates, and investigate the relationships between lake Ca and soil and catchment attributes. The MRC is acid-sensitive, and has a long history of impacts from industrial emission sources in Ontario and the United States. Small headwater catchments were sampled for soil and landscape attributes (e.g. elevation, slope, catchment area) at 84 sites. Soil Ca weathering rates, estimated with the PROFILE model, were low throughout the region (average: 188 eq/(ha·yr)) compared to global averages, and lower than Ca deposition (average: 292 eq/(ha·yr)). Multiple linear regression models of lake Ca (n= 306) were dominated by landscape variables such as elevation, which suggests that on a regional scale, landscape variables are better predictors of lake Ca than catchment soil variables. Author Keywords: Calcium, Lakes, Regional assessment, Regression, Soils, Weathering
Representations of Missing and Murdered Indigenous Women in Canadian Art
This thesis focuses specifically on artistic projects that address violence against indigenous women and uses an interdisciplinary approach to examine their meaning and reception. I argue that the mainstream media has negatively stereotyped missing and murdered indigenous women and that art projects have the ability to reframe their lives to the viewing public. I focus on five case studies of works, including Vigil (2002) by Rebecca Belmore, REDress (2011) by Jamie Black, The Forgotten (2011) by Pamela Masik, Walking With Our Sisters (2013) by Christi Belcourt and Shades of Our Sisters (2017), created by Ryerson University students and produced by Maggie Cywink, Alex Cywink and Joyce Carpenter. Art has the capacity to encourage activism, raise awareness and promote reconciliation between indigenous and non-indigenous people. Comparisons can be drawn between how the case studies of these art works have framed the lives of missing and murdered women and the dominant media images that have prevailed in Canadian society. Author Keywords: activism, art, Canada, indigenous, missing and murdered indigenous women, symbolism
Phosphoric Acid Chemically Activated Waste Wood
Activated Carbon (AC) is commonly produced by gasification, but there has been increasing interest in chemical activation due to its lower activation temperatures and higher yields. Phosphoric acid, in particular, succeeds in both these areas. Phosphoric acid activated carbon (PAC) can be environmentally sustainable, and economically favourable, when the phosphoric acid used in the activation is recycled. This thesis describes the digestion and activation of waste wood using phosphoric acid, as well as methods used to recover phosphoric acid, functionalize the produced activated carbon with iron salts and then test their efficacy on the adsorption of target analytes, selenite and selenate. In order to achieve an efficient phosphoric acid based chemical activation, further understanding of the activation process is needed. A two-step phosphoric acid activation process with waste wood feed stock was examined. The filtrate washes of the crude product and the surface composition of the produced PAC were characterized using X-ray Photoelectron Spectroscopy (XPS), Fourier Transform-Infrared spectroscopy (FT-IR), Ion Chromatography (IC), and 31P Nuclear Magnetic Resonance (NMR). XPS of the unwashed PAC contained 13.3 atomic percent phosphorous, as phosphoric acid, while the washed sample contained 1.4 atomic percent phosphorous as PO43-, and P2O74-. Using 31P NMR, phosphoric acid was identified as the primary phosphorous species in the acidic 0.1 M HCl washings, with pyrophosphates also appearing in the second 0.1 M NaOH neutralizing wash, and finally a weak signal from phosphates with an alkyl component also appearing in the DI wash. IC showed high concentrations of phosphoric acid in the 0.1 M HCl wash with progressively lower concentrations in both the NaOH and DI washes. Total phosphoric acid recovery was 96.7 % for waste wood activated with 25 % phosphoric acid, which is higher than previous literature findings for phosphoric acid activation. The surface areas of the PAC were in the 1500-1900 m2g-1 range. Both pre and post activation impregnation of iron salts resulted in iron uptake. Pre-activation resulted in only iron(III) speciation while post-activation impregnation of iron(II)chloride did result in iron(II) forming on the PAC surface. The pre-activated impregnated PAC showed little to no adsorption of selenite and selenate. The post-activation impregnated iron(II)chloride removed up to 12.45 ± 0.025 mg selenium per g Iron-PAC. Competitive ions such as sulfate and nitrate had little effect on selenium adsorption. Phosphate concentration did affect the uptake. At 250 ppm approximately 75 % of adsorption capacity of both the selenate and the selenite solutions was lost, although selenium was still preferentially adsorbed. Peak adsorption occurred between a pH of 4 and 11, with a complete loss of adsorption at a pH of 13. Author Keywords: Activated Carbon, doping, Iron, phosphoric acid, selenium
Social Anxiety and Emotional Competence
Prior research has examined social anxiety, emotional competence (EC) and life adjustment (i.e., loneliness and life satisfaction) using cross-sectional designs, although there is limited information on their association over time. The present study examined the impact of social anxiety on life adjustment and assessed if EC could mediate this relationship from young to middle adulthood. University students (N = 283) completed self-report measures at two time points: in first year university and 15 years later. The results accord with previous research demonstrating the stability and slight decrease of social anxiety over time. Social anxiety in young adulthood was a robust predictor of loneliness in middle adulthood, and a weak predictor of life dissatisfaction for men. Mediation analyses revealed that social anxiety was indirectly associated with interpersonal adjustment via EC, especially the intrapersonal EC domain. Social anxiety requires early intervention and EC may help to prevent later social anxiety and maladjustment. Author Keywords: emotional intelligence, life adjustment, social anxiety
Identifying non-local individuals at the ancient Maya centre of Minanha, Belize through the use of strontium isotope analysis
Strontium isotope analysis has become an important tool in identifying non-local individuals at archaeological sites. For this study, tooth enamel samples were collected from 20 individuals from the ancient Maya centre of Minanha, Belize. These individuals date to periods spanning the formative occupation of the centre, as well as its fluorescence and protracted decline. The goal of this research was to investigate if non-local individuals played a role in Minanha's formation and fluorescence. The study utilised published strontium isotope maps from Belize and the Yucatán in order to establish local 87Sr/86Sr values. The values of the Minanha enamel samples (n = 20) fell predominantly outside of the expected strontium isotope range; this result seemed implausible and an alternative method was utilised to establish the local 87Sr/86Sr values. The outlier method identified 5/20 (25%) non-local individuals. All of the non-local individuals had 87Sr/86Sr values that coincided with published 87Sr/86Sr values reported from within 10 - 20 km of Minanha. However, some strontium isotope values also corresponded with 87Sr/86Sr values reported from regions >50 km away. The percentage of non-locals at Minanha is consistent with other Mesoamerican centres. This study emphasises the importance of collecting local baseline 87Sr/86Sr values from sites themselves, as 87Sr/86Sr values from neighbouring regions might not reflect local strontium isotope values. Author Keywords: Ancient Maya, bioarchaeology, migration, mobility, Vaca Plateau
Range-Based Component Models for Conditional Volatility and Dynamic Correlations
Volatility modelling is an important task in the financial markets. This paper first evaluates the range-based DCC-CARR model of Chou et al. (2009) in modelling larger systems of assets, vis-à-vis the traditional return-based DCC-GARCH. Extending Colacito, Engle and Ghysels (2011), range-based volatility specifications are then employed in the first-stage of DCC-MIDAS conditional covariance estimation, including the CARR model of Chou et al. (2005). A range-based analog to the GARCH-MIDAS model of Engle, Ghysels and Sohn (2013) is also proposed and tested - which decomposes volatility into short- and long-run components and corrects for microstructure biases inherent to high-frequency price-range data. Estimator forecasts are evaluated and compared in a minimum-variance portfolio allocation experiment following the methodology of Engle and Colacito (2006). Some consistent inferences are drawn from the results, supporting the models proposed here as empirically relevant alternatives. Range-based DCC-MIDAS estimates produce efficiency gains over DCC-CARR which increase with portfolio size. Author Keywords: asset allocation, DCC MIDAS, dynamic correlations, forecasting, portfolio risk management, volatility
Understanding the establishment of Typha spp. in North America using population genetics and common garden studies
There are three cattail (Typha) taxa in Canada: T. latifolia (native), T. angustifolia (introduced), and their hybrid T. x glauca. The latter is invasive in regions around the Laurentian Great Lakes, and I investigated the potential role that commercial suppliers may be playing in the introduction of non-native Typha by comparing genotypes of North American, European, and commercially available plants. I found that Ontario garden centres are importing both hybrids and non-native lineages of T. angustifolia into Canada, but was unable to identify the provenance of T. latifolia. I also investigated the possibility that the hybrid cattail leaf litter shade and leachate influences germination and early growth of the parental species of the hybrids. Using three common garden experiments, I found that T. x glauca leaf litter suppresses germination rates of the three taxa. In the early seedling growth experiment, plant performance varied by taxa, and for the competition experiment there were no intra- or interspecific competition or treatment effects on the performance of plants. Overall, my research identified a potential mechanism allowing T. x glauca to dominate wetlands, and also shows that non-native lineages are being introduced into Canada through commercial trade Author Keywords: Competition, Germination, Non-native lineages, Plant nurseries, Seedling Growth, Typha spp.
"Multimodal Contrast" from the Multivariate Analysis of Hyperspectral CARS Images
The typical contrast mechanism employed in multimodal CARS microscopy involves the use of other nonlinear imaging modalities such as two-photon excitation fluorescence (TPEF) microscopy and second harmonic generation (SHG) microscopy to produce a molecule-specific pseudocolor image. In this work, I explore the use of unsupervised multivariate statistical analysis tools such as Principal Component Analysis (PCA) and Vertex Component Analysis (VCA) to provide better contrast using the hyperspectral CARS data alone. Using simulated CARS images, I investigate the effects of the quadratic dependence of CARS signal on concentration on the pixel clustering and classification and I find that a normalization step is necessary to improve pixel color assignment. Using an atherosclerotic rabbit aorta test image, I show that the VCA algorithm provides pseudocolor contrast that is comparable to multimodal imaging, thus showing that much of the information gleaned from a multimodal approach can be sufficiently extracted from the CARS hyperspectral stack itself. Author Keywords: Coherent Anti-Stokes Raman Scattering Microscopy, Hyperspectral Imaging, Multimodal Imaging, Multivariate Analysis, Principal Component Analysis, Vertex Component Analysis
Effects of flooding on nutrient budgets and ecosystem services
Increases in flooding due to anthropogenic influences such as climate change and reservoir creation will undoubtedly impact aquatic ecosystems, affecting physical, chemical, and biological processes. We used two approaches to study these impacts: a whole-ecosystem reservoir flooding experiment and a systematic literature review. In the whole-ecosystem experiment, we analyzed the impact of flooding on nutrient release from stored organic matter in an upland forest. We found that flooded organic matter produced N (nitrogen) and P (phosphorus), but that more N was released relative to P, increasing the N:P ratio over time. In the systematic literature review, we linked small (<10 year recurrence interval) and extreme (>100 year recurrence interval) floods to changes in 10 aquatic ecosystem services. Generally, extreme floods negatively impacted aquatic ecosystem service provisioning, while small floods contributed positively. Overall, we found that flood impacts vary depending on ecosystem properties (organic matter content) and flood characteristics (magnitude). Author Keywords: ecosystem services, flooding, nutrients, reservoirs, rivers
relationship of policy aims and implementation
Background: Ontario’s Ministry of Health and Long Term Care (MOHLTC) claims people with mental illnesses/addictions need improved care/overuse emergency departments. MOHLTC expects Coordinated Care Planning (CCP, teams of mental/physical health professionals, social workers and informal caregivers) to improve care and lower emergency department returns/healthcare costs. CCPs are directed by policies, Smith’s “problematics,” or Deleuze’s “expressions,” supposedly reflecting “contents”/“everyday worlds.” Research Question: How do Ontario health/allied professionals come together with a person with mental illness/addictions and informal caregiver(s) to address health needs through a CCP? Method: 1) Analyzed CCP policies; generated questions about creation/implementation. 2) Interviewed eight professionals about interpreting/enacting policies. 3) Connected interview data to policies. Findings: Opportunities for fragmentation exist in gaining consent; determining eligibility; persons in care, informal caregivers and professionals’ participation; person-centeredness; “shame-free” environments; health literacy; records of medications. Conclusion: CCP participants need to minimize fragmentations which takes time, space, money; creates contradictions in lowering costs/improving care. Author Keywords: Addiction, Dual Diagnosis, Health Care Policy, Institutional Ethnography, Integrated Health Care, Mental Illness

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