Graduate Theses & Dissertations

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Using ultra high-resolution mass spectrometry to characterize the biosorbent Euglena gracilis and its application to dysprosium biosorption
Euglena gracilis is an enigmatic and adaptable organism that has great bioremediationpotential and is best known for its metabolic flexibility. The research done in this dissertation addresses (1) how growth conditions impact cellular composition, and (2) how chemometric approaches (such as statistical design of experiments and artificial neural networks) are viable alternatives to the conventional biosorption models for process optimization. Using high-resolution mass spectrometry for biosorbent characterization is a powerful way to assess the chemical characteristics of lyophilized and fractionated cells with high precision, especially to screen for compound classes that may have potentiality for rare earth element removal. Growth conditions impacted cellular composition and separated size fractions of cells yielded different molecular/chemical properties as described by compositional abundances, thus different biosorptive potential. Untargeted analysis demonstrated that exponential dark-grown cells with glucose supplementation were abundant in polyphenolic- and carbohydrate-like compounds, molecular species highly involved in rare earth element binding. Light grown cells had more heterogeneity and the highest molecular weighted fractions from light grown cells (fraction D) had the most abundances of polyphenolic- and protein-like structures. Chemometric modeling used identified the best and worst conditions for iii dysprosium sorption and showed that pH had the most significant influence on bioremoval. Bioremoval ranged from 37% at pH 8 to 91% at pH 3 at Dy concentration ranging from 1 to 100 μg L-1. The work presented in the PhD dissertation will aid in understanding the chemical characteristics of biosorbents by using a Van krevelen analysis of elemental ratios whether algal cells are grown in different environmental growth conditions, or when algal cell are size fractionated. This is especially applied for the screening for metal binding potentiality to Dysprosium. Chemometric methods provide an alternative method for the investigating factors for bioremoval, and applications for process optimization and for real-world applications. This dissertation will aid in understanding chemical characteristics when a biosorbent is grown in a given condition and which factors are important for rare earth element (REE) bioremoval. The significance of this work aims to look for alternate ways to screen biosorbents and using a more efficient experimental design for REE bioremoval. Author Keywords: bioremoval, biosorption, chemometrics, dysprosium, euglena, mass spectrometry
Unsettling Inner Landscapes
Recent climate scientists, Indigenous resurgence scholars, and psychologists have variously indicated that we need a transformation of consciousness in order to address the cultural and spiritual forces at the root of our current environmental, interpersonal, and individual crises of disconnection. My research is in direct response to diverse calls for this paradigm shift, including the words of Elders such as the late Grandfather William Commanda who encouraged settlers such as myself to ‘remember our original instructions’. Through an anti-colonial and trauma-informed lens, my goal has been to strategically inform my roles and responsibilities in healing the disconnection and abuses in what I term the trilogy of my relationships to self, others, and Land. This study is both a critical auto-ethnography and as well as a theoretical engagement with Indigenous resurgence, settler colonialism, and sustainability discourses. I share dialogues with Anishinaabe-kweg in my community with whom I have established relationships and the results of our discussions focus on holistic models of transforming settler consciousness. What emerges is an emotional, uncertain, and yet radically hopeful narrative that points to the urgency of centering Indigenous sovereignty and Indigenous relationship models while endeavouring to reconstruct a sense of identity and belonging along more accountable lines. Recovering a sense of my Celtic epistemology and story work is offered as a strategic exemplar of how settlers might begin to remember and co-create more balanced, respectful, and reciprocal relationships with and within place. Nurturing an embodied spiritual practice of deep listening, critical self-reflection, and collective action is discussed as potentially central to sustaining a decolonizing praxis for white settler Canadians more broadly. Author Keywords: Critical auto-ethnography, Critical Spirituality, Decolonization, Indigenous-settler relations, Original Instructions, Settler colonial studies
Women's Lived Experience of Risk in Pregnancy
Cardiovascular disease (CVD) prevention, treatment and outcomes in women remain largely inequitable globally. Unique sex-specific stages of life, including pregnancy conditions, and their influence on cardiac risk is a growing area of research (Norris et al., 2020). For example, preeclampsia is strongly associated with CVD risk. This connection has led to prevention interventions such as postpartum risk clinics. Research to date on pregnancy and chronic disease is rooted in the medical paradigm of risk and lacks women’s lived experience. The present study qualitatively explored illness and risk perceptions of women with risky pregnancy conditions. Some participants felt self-blame for their conditions. Consequences and severity were focused on “baby first”, while maternal risk was viewed in the distant future. Aspects of the pregnancy experience, including prompt access to mental health support, was viewed as a “blessing in disguise”. Risks, such as lack of agency, and benefits of healthcare risk communication and intervention and implications for practice were also explored. Author Keywords: communication, critical, health care, phenomenology, pregnancy, risk
Experiences of Seven Deaf & Hard-of-Hearing Alumni of Ontario’s Education System
Through narrative/life story research this study explores the educational experiences of six individuals identified as Deaf or hard-of-hearing. The research presented will be conveyed in the form of an autoethnography, an approach to research and writing that seeks to describe and analyze personal experience to understand cultural experience. I will combine the views of participants who have been part of the Ontario Public School System within the last 10-15 years (2004-2019), with my own educational experience, learning with hearing loss. In this study, three interrelated concepts—student engagement, motivation, and resilience—are examined through the lens of “mindsets.” Mindsets are “assumptions that we possess about ourselves and others that guide our behaviour” (Brooks, 2012, p. 1). The research reviewed in this paper, shows that students’ beliefs about their academic ability can influence their academic tenacity. Academic tenacity refers to the mindsets and skills that enable students to: establish long-term goals and persevere in the face of adversity. I illuminate some of the systemic factors which impact the mindsets of students who are Deaf and hard-of-hearing. The design lies within the qualitative spectrum; data were gathered and analyzed from open-ended interviews conducted with purposively selected participants. Author Keywords: Academic Tenacity, Autoethnography, Deaf, Education, Hard-of-Hearing, Mindsets
Community Coalescence and Regional Geospatial Trends of Ceramic Decorative Variation in Late Woodland Northern Iroquoia
This case study focuses on geospatial patterns of decorative variation in pottery assemblages from 234 Northern Iroquoian village communities, occupied between ca. 1350–1650 CE. Previous interpretations of these assemblages’ ceramic decorative variability have been based on the assertion that potters from these communities used collar decorative motifs as communicative social signals. However, they did not consider whether these geospatial decorative patterns could simply reflect the outcome of stochastic macroscale social learning processes driven solely by probabilistic information exchange between closer neighboring communities. Cultural transmission, the theoretical framework applied here, is well-suited to address this perspective. Thus, the primary research question of this case study is, “Are the expected outcomes of random copying processes sufficient to explain the range of geospatial ceramic decorative variability observed across Northern Iroquoia?” Random copying processes are the stochastic, probabilistic social learning mechanisms driving the collective decisions of multiple communities, making up one side of the “random-selective copying spectrum.” When the decorative decisions of multiple communities are collectively guided by shared ideas (such as, potentially, symbolic communication structures), they become subsumed under the broad umbrella of “selective copying” processes. The social learning mechanisms involved on both sides have predictable geospatial and structural ranges of ceramic decorative patterning. The goal of this case study was thus to evaluate the range of patterning in Northern Iroquoia, both generally as well as at narrower temporal and spatial scales. Ultimately, region-specific temporal trends in selective copying processes seeming to reflect recently established temporal trajectories of community coalescence were identified. Author Keywords: coalescence, cultural population structure, cultural transmission, isolation by distance, Northern Iroquoia, social signaling
Examining the Diet of Early Nomadic Pastoralists in Southern Mongolia Using Carbon and Nitrogen Stable Isotope Analysis
This study reconstructs the diet of pastoral populations from Bronze Age Southern Mongolia and Early Iron Age Central Mongolia using stable carbon and nitrogen isotope analysis of bone collagen from 44 individuals. Spatial and temporal differences were investigated and interpreted in combination with paleoenvironmental, archaeological, genetic and other stable isotope data. The Southern Mongolian diet is consistent with a mixed diet including C3 and C4 plants and large amounts of animal products from herd animals such as sheep/goat, horses and cattle. The δ13C values from Bronze Age Southern Mongolia are consistent with the consumption of C4 plants, most likely millet, obtained through trade with Northern China although environmental aridity might also be responsible for this pattern. The diet was relatively constant over time but spatial differences in Mongolia and Central Asia indicate variation in subsistence strategies based on environmental and cultural context. This thesis highlights the flexibility of pastoralism and its adaptability in the face of environmental and cultural changes. Author Keywords: Bronze Age, carbon and nitrogen isotopes, Mongolia, nomadic pastoralism, paleodiet, stable isotope analysis
Teacher Efficacy as an Indicator of how Mathematics Educators Perceive the Value of Professional Learning Experiences
This study investigates the potential for a responsive model of professional development in mathematics education which acknowledges how teachers perceive the value of professional learning, and examines how those perceptions are connected to teacher efficacy. Three fields of educational research ground this study: (i) professional development strategies in mathematics education, (ii) teacher efficacy, and (iii) self-determination theory and andragogy. Data collection and analysis involved four detailed case studies and a cross-case analysis of similarities and distinctions among the cases, in an instrumental-multiple-case study design. Results suggest: (1) some characteristics of professional development were consistently designated as high or low value, independent of efficacy ratings, (2) other professional learning experiences were valued relative to the participants’ sense of efficacy at different times in their careers, and (3) characteristics of professional development designated as high value during periods of low efficacy were fundamentally teacher-centric, but during periods of high efficacy, they were fundamentally student-centric. Author Keywords: efficacy, mathematics education, mathematics teachers, professional development, professional learning, teacher efficacy
Ohwén
Ohwén:tsia Entsionkwarihón:nien is a project that explores the intersection of Kanien’kéha immersion, Kanien’kehá:ka culture and the potential impacts of experiencing Rotinonhsón:ni knowledge on the land. Students at the Akwesasne Freedom School are fully immersed in the Kanien’kéha language and the “curriculum” is centered around four Rotinonhsón:ni systems of knowledge. What is missing, as identified by the teachers, is consistent opportunities for students to physically be on the land. This project asks how can we ensure that future generations of Onkwehónwe children can embody their language and their culture in connection to the land. The resulting “curriculum” then shifts from determining what students will learn, to listening to what the land has to teach. A land-based program by the AFS can translate to educational control, cultural sustainability, food sovereignty, environmental stewardship, community empowerment and linguistic revitalization; each of these is a critical component of building and rebuilding communities and nations. Author Keywords: Indigenous methodology, Land-Based Education, Rotinonhsón:ni, Storytelling
Educational Data Mining and Modelling on Trent University Students’ Academic Performance
Higher education is important. It enhances both individual and social welfare by improving productivity, life satisfaction, and health outcomes, and by reducing rates of crime. Universities play a critical role in providing that education. Because academic institutions face resource constraints, it is thus important that they deploy resources in support of student success in the most efficient ways possible. To inform that efficient deployment, this research analyzes institutional data reflecting undergraduate student performance to identify predictors of student success measured by GPA, rates of credit accumulation, and graduation rates. Using methods of cluster analysis and machine learning, the analysis yields predictions for the probabilities of individual success. Author Keywords: Educational data mining, Students’ academic performance modelling
Legacy Effects Associated with the World’s Largest Ongoing Liming and Forest Regeneration Program in Sudbury, Ontario, Canada
Soil and tree chemistry were measured across 15 limed sites that were established 14 to 37 years ago within the Sudbury barrens in Ontario, along with two unlimed pre-treatment condition reference sites and an unlimed remnant pine forest. Soil pH and base cation (calcium (Ca), magnesium (Mg), and potassium (K)) concentrations were elevated in surface organic [FH] horizons up to 37-years post limestone treatment. Limestone in the organic horizon was evident by higher Ca/Sr ratios (a good marker of dolomite) in younger sites. Base cation mass budgets were generally unable to account for the mass of added Ca and Mg. Sudbury is characterized by widespread metal contamination. Metal (copper (Cu), nickel (Ni), and lead (Pb)) concentrations were generally greatest within the FH horizon and unrelated to stand age. Copper and Ni concentrations in soil generally decreased with distance from the nearest smelter. Metal partitioning (Kd) in soil was most influenced by soil pH rather than organic matter suggesting that as liming effects fade over time metal availability may increase. Author Keywords: Afforestation, Degraded, Limestone, nutrient, Space-for-time, Sudbury
Sinc-Collocation Difference Methods for Solving the Gross-Pitaevskii Equation
The time-dependent Gross-Pitaevskii Equation, describing the movement of parti- cles in quantum mechanics, may not be solved analytically due to its inherent non- linearity. Hence numerical methods are of importance to approximate the solution. This study develops a discrete scheme in time and space to simulate the solution defined in a finite domain by using the Crank-Nicolson difference method and Sinc Collocation Methods (SCM), respectively. In theory and practice, the time discretiz- ing system decays errors in the second-order of accuracy, and SCMs are decaying errors exponentially. A new SCM with a unique boundary treatment is proposed and compared with the original SCM and other similar numerical techniques in time costs and numerical errors. As a result, the new SCM decays errors faster than the original one. Also, to attain the same accuracy, the new SCM interpolates fewer nodes than the original SCM, which saves computational costs. The new SCM is capable of approximating partial differential equations under different boundary con- ditions, which can be extensively applied in fitting theory. Author Keywords: Crank-Nicolson difference method, Gross-Pitaevskii Equation, Sinc-Collocation methods
Effects of hydrologic seasonality on dissolved organic matter composition, export, and biodegradability in two contrasting streams
Environmental and seasonal processes are important watershed drivers controlling the amount, composition, and fate of dissolved organic matter (DOM) in aquatic ecosystems. We used ten months of water samples and eight months of bioassay incubations from two contrasting catchments (agriculture and natural, forested) to assess the effects of seasonal variability on the composition, export, and biodegradability of DOM. As expected, the DOM composition and exports were more allochthonous-like and autochthonous-like in the forest and agriculture streams, respectively. However, we found no relationship between DOM composition and biodegradability in our study, suggesting that broad environmental factors play a large part in determining bioavailability of DOM. We found that both differences between the catchments and seasonal variability in hydrology and water temperature cause shifts in DOM composition that can affect exports and potentially affect its susceptibility to microbial activity. More research is needed to fully understand the impact of land use and temporal variability on bioavailability and delivery to downstream ecosystems. Author Keywords: Bioavailable dissolved organic carbon, Biodegradability, Dissolved organic matter, Export, Seasonality, Streams

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Format: 2023/10/03