Graduate Theses & Dissertations


Cytokinin biosynthesis, signaling and translocation during the formation of tumors in the Ustilago maydis-Zea mays pathosystem
Cytokinins (CKs) are hormones that promote cell division. During the formation of tumors in the Ustilago maydis-Zea mays pathosystem, the levels of CKs are elevated. Although CK levels are increased, the origins of these CKs have not been determined and it is unclear as to whether they promote the formation of tumors. To determine this, we measured the CK levels, identified CK biosynthetic genes as well as CK signaling genes and measured the transcript levels during pathogenesis. By correlating the transcript levels to the CK levels, our results suggest that increased biosynthesis and signaling of CKs occur in both organisms. The increase in CK biosynthesis by the pathosystem could lead to an increase in CK signaling via CK translocation and promote tumor formation. Taken together, these suggest that CK biosynthesis, signaling and translocation play a significant role during the formation of tumors in the Ustilago maydis-Zea mays pathosystem. Author Keywords: Biosynthesis, Cytokinins, Signaling, Translocation, Ustilago maydis, Zea mays
Building Individuals, Building the Economy
This thesis explores the neoliberal governmentality approach to education for Northern economic development that was prevalent from 2006 to 2015, during Stephen Harper’s period as Prime Minister of Canada. Using a grounded theory approach, this thesis identifies three themes – Indigenous integration, education, and employment for labour force/ economic development – to direct an analysis on programs and funding supported by the Canadian Northern Economic Development Agency, Employment and Social Development Canada, and Indigenous and Northern Affairs Canada. This examination suggests that Federal programming and funding encouraged neoliberal governmentality approaches to Northern development and education. Specifically, the former Government interest in developing an Indigenous work force to serve labour market needs is brought to light. Author Keywords: Economic Development, Indigenous Education, Labour Force Development, Neoliberalism, Territorial North
From Foraging to Farming
This study examines foraging strategies during the Middle Woodland Period’s Sandbanks Phase (A.D. 700–1000) on Boyd Island, Pigeon Lake, Ontario. The faunal remains analyzed in this study were recovered from a site associated with the procurement of aquatic and terrestrial taxa. Detailed taphonomic analyses have revealed that the Boyd Island faunal remains were affected by weathering and human transport decisions. White-tailed deer was the most frequently acquired prey at Boyd Island, followed by black bear. Using the central place forager prey choice model as a framework, the analysis of diet breadth and carcass transport patterns suggests that most animal resources were acquired from both aquatic and terrestrial habitats, at moderate distances from the site. Incomplete carcasses of large game appear to have been transported away from the site, where they were subsequently processed for provisioning or consumption. Comparisons with other Sandbanks faunal assemblages and those dating to later periods indicate significant differences in terms of taxonomic composition, while continuing to emphasize the use of fish. It is suggested that the Middle Woodland foragers adopted subsistence strategies focusing on the exploitation of local habitats in which productivity may have been enhanced through niche construction associated with the low-level food production activities. Author Keywords: animal resource exploitation, archaeozoology, foraging theory, Middle Woodland, niche construction theory, southcentral Ontario
New Interpretations from Old Data
Range contractions and expansions are important ecological concepts for species management decisions. These decisions relate not only to rare and endangered species but to common and invasive species as well. The development of the broad spatiotemporal extent models that are helpful in examining range fluctuations can be challenging given the lack of data expansive enough to cover the time periods and geographic extents needed to fit the models. Archival records such as museum databases and harvest data can provide the spatiotemporal extent needed but present statistical challenges given they represent presence-only location information. In this thesis, I used maximum entropy and Bayesian hierarchical occupancy algorithms fitted with archival presence-only records to develop spatiotemporal models covering broad spatial and temporal extents for snowshoe hare and Canada lynx. These two algorithm types are well suited for presence-only data records and can be adapted to include biological and physical processes, thus improving the ecological realism of the models. Using these modelling methods, I found the extent of occurrence (EOO) and area of occupancy (AOO) varied greatly over time and space for both snowshoe hare and Canada lynx, suggesting that management decisions for these species should include consideration of these variations. While the presence-only data were appropriate for model development and understanding changing values in EOO and AOO, it sometimes lacked the locational accuracy and precision needed to create fine scale ecological analyses, thus resulting in somewhat coarse but potentially relevant conclusions. Author Keywords: Area of occupancy, Bayesian hierarchical models, Canada lynx, Extent of occurrence, Presence-only data, Snowshoe hare
Effect of Carbon Source and Phytohormones on the in vitro Growth of Euglena Gracilis
Microalgae are a promising source of valuable compounds relevant to biofuels, biomaterials, nutraceuticals as well as animal and human nutriment. Unfortunately, low cell density and slow growth result in reduced economic feasibility. Heterotrophic cell culturing using an organic carbon source in lieu of light has proven to be an effective alternative to photobioreactors; however, further improvement may be possible with the addition of growth promoting phytohormones. In this thesis, growth and endogenous hormone profiles in heterotrophic cultures of Euglena gracilis were evaluated using glucose and ethanol as carbon sources. Cytokinin (CK) and abscisic acid (ABA) were quantified by HPLC-ESI-MS/MS and compared to culture growth dynamics. Exogenous phytohormones treatments were also conducted to determine if they may mitigate nutrient reduction and improve growth. Phytohormones CK and ABA were purified and analyzed at seven points along the growth curve in small scale (250 mL flasks, 100 mL working volume) cultures. Among the key findings was that ethanol cultures undergoing exponential growth, primarily synthesize freebase cytokinins (FBCKs) and methylthiol-cytokinins (MeSCKs), while not producing detectable levels of ABA. In exogenous studies, dry biomass was positively influenced with the addition of exogenous ABA; however, the most notable result revealed the ability of transZ to alleviate nutrient reduction. These findings suggest a communication network in algal culture using FBCKs and MeSCKs, as well as the potential for exogenous hormone supplementation to increase growth rates and overall biomass productivity. Author Keywords: abscisic acid, cytokinin, Euglena gracilis, heterotrophy, phytohormones
Reconciliation as Relationship
In 2015, Canada’s Truth and Reconciliation Commission called upon Canadians to reconcile relationships between Settlers and Indigenous peoples in Canada. Education for reconciliation is one important element of this process. However, critical questions arise when education is undertaken by and for Settlers such as myself: Are our undertakings actually fostering reconciliation? According to whom? Drawing from reconciliation theory and decolonizing Indigenous methodologies, a reconciliation methodology is created to consider this question in the context of three reconciliation workshops for Settlers. Indigenous perspectives and pedagogies are prioritized. The emerging understandings of reconciliation as relationship and relationship as pedagogy reframe some prevailing Settler thinking about reconciliation, unmask latent assumptions linked to the colonial habits of mind and affirm the need for personal responsibility in the reconciliation relationship. The Indigenous norm of learning in-relation is found to be a powerful experience for Settlers participants offering valuable insights for reconciliation education in Canada. Author Keywords: decolonizing, education, Indigenous, relationship, Settler, Truth and Reconciliation
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
Farmer knowledge exchange about climate change adaptation in the Peterborough region of Southern Ontario
Agricultural adaptation is a significant component of the larger challenge humans face in adapting to the impacts of climate change. There are extensive studies of agricultural adaptation, however little is known about how farmers in Ontario share knowledge about effective adaptation practices. This qualitative research study contributes to the understanding of the educational context within which Ontario farmers meet the demands of extreme weather on their farms. The research investigates how farmers exchange knowledge about climate change adaptation. Eight semi-structured interviews were conducted in the context of a grounded theory research approach and coded according to the systematic design. Results suggest that knowledge transfer is two-fold: farmers adapt to stresses through experimentation and engage in knowledge exchange through informal and non-institutional formal education. This study outlines the mechanisms by which adaptation and knowledge transfer occur. Implications of the research are discussed in relation to academic literature and policy. Author Keywords: agricultural adaptation, Climate change, education, farming, grounded theory research, knowledge exchange
review of the first- and second-year experience of a group of Trent University students admitted below admission requirements
This study used qualitative research methods to explore the first- and second-year experiences of Trent University students who were admitted below admission requirements in September 2015. Through review of an on-line questionnaire completed by 13 students and two-rounds of semi-structured interviews completed by 5 students, information was gathered on the students’ experiences, specifically regarding self-efficacy for academic achievement, self-efficacy for self-regulated learning, locus of control, student engagement, and sense of belonging. The major findings of this case study were grouped into four driving themes: self-awareness as a learner, goal-setting and motivation, the Trent community, and course experience. Participants of the study felt that the inclusive social and learning environments at Trent University enhanced their sense of belonging within the university community. These findings are not meant to be generalized, as they arose from this specific group of students at Trent University. Author Keywords: first-year experience, locus of control, post-secondary, self-efficacy, sense of belonging, student engagement
“At least I can feel like I’ve done my job as a mom”
This study examines the household foodwork of low-income mothers in Peterborough, Ontario and considers how community food initiatives (CFIs) such as community gardens and good food box programs can support these women in their efforts to feed their families adequately. I draw on multiple data sources: interviews with representatives from Peterborough CFIs; interviews with and illustrations by 21 local low-income mothers; debrief sessions following participants’ tours of CFIs; and my ongoing involvement with two local food networks. The mothers’ extensive foodwork considerations, strategies, and struggles reflect an engagement with three main ideals that are placed further out of reach through poverty and food insecurity. Women experienced pressure through these ideals: the “good mother,” to take primary responsibility for their children’s well-being through food; the “good consumer,” to participate in society as individual consumers; and the “good food program participant,” to avoid indications of over-reliance on food programs. Each ideal reflects the neoliberal exaltation of self-sufficiency and its flipside, the vilification of dependence. The research results highlight the need for CFIs to focus on the broader, systemic discursive and material challenges that can hamper the foodwork of all low-income mothers, in addition to addressing the immediate needs of their own participants. Towards this goal, Peterborough CFIs employ principles of universality, social inclusion, democratic processes, and broadening of social imaginaries. In their efforts, CFIs must navigate between cultivating collectivity and interdependence on the one hand, and engaging with this familiar, individualizing neoliberal ethos on the other hand. This study provides insights about the subjectivities of low-income mothers that may be useful for CFI programming as well as more analytic examinations of the role and impact of CFIs. It also reveals the common feminization, devaluation, and under resourcing of the food-related work of both mothers and CFIs. In doing so, the study points to the urgent need for broad dialogue and political action regarding poverty, dependence, caring labour, and the roles of citizens and the state in ensuring that households can adequately feed themselves. Author Keywords: Community Food Initiatives, Community Food Programs, Domestic Labour, Food Insecurity, Gendering of Caring Labour, Household Food Work
Compression Cone Method on Existence of Solutions for Semi-linear Equations
With wide applications in many fields such as engineering, physics, chemistry, biology and social sciences, semi-linear equations have attracted great interests of researchers from various areas. In the study of existence of solutions for such class of equations, a general and commonly applied method is the compression cone method for fixed-point index. The main idea is to construct a cone in an ordered Banach space based on the linear part so that the nonlinear part can be examined in a relatively smaller region. In this thesis, a new class of cone is proposed as a generalization to previous work. The construction of the cone is based on properties of both the linear and nonlinear part of the equation. As a result, the method is shown to be more adaptable in applications. We prove new results for both semi-linear integral equations and algebraic systems. Applications are illustrated by examples. Limitations of such new method are also discussed. Keywords: Algebraic systems; compression cone method; differential equations; existence of solutions; fixed point index; integral equations; semi-linear equations. Author Keywords: algebraic systems, differential equations, existence of solutions, fixed point index, integral equations, semi-linear equations
“I will not use the word reconciliation” – Exploring Settler (Un)Certainty, Indigenous Refusal, and Decolonization through a Life History Project with Jean Koning
This thesis centres on a series of intergenerational life history interviews with and about Jean Koning, a 95-year-old white Settler woman who has engaged in different forms of Indigenous-Settler solidarity work for over fifty years—work that is highly regarded by many Indigenous and non-Indigenous peoples in southwestern and central Ontario. I bring Jean’s stories and perspectives, many of which stand in stark contrast to dominant discourses of “reconciliation,” into conversation with scholars who examine Indigenous refusal and Settler (un)certainty. Through this, I attempt to better understand how colonial knowledge structures and ways of thinking operate in practise, how these might be resisted, and how this resistance relates to land repatriation. I argue that a commitment to unsettling uncertainty and to meaningful listening may be required by Settlers in a stand against various colonial ways of thinking, such as cognitive imperialism. Author Keywords: Cognitive imperialism, Decolonization, Indigenous-Settler relations, Life history, Reconciliation, Settler uncertainty


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