Graduate Theses & Dissertations

Pages

Exploring the Role of Natural Antisense Transcripts in the Stress Response of Ustilago maydis
Fungal pathogens adapt to environmental changes faster than their hosts, due in part to their adaptive mechanisms exhibited in response to stress. Ustilago maydis was used to investigate potential natural antisense transcript (NAT) RNA-mediated mechanisms that enhance fungal adaptation to stress. Of the 349 NATs conserved amongst U. maydis and two related smut fungi, five NATs were identified as having altered transcript levels in response to multiple stress conditions. Subsequently, antisense transcript expression vectors were created for select NATs and transformed into U. maydis haploid cells. When exposed to stress conditions, two antisense expressing mutant strains exhibited alterations in growth. RT-qPCR analysis of mRNA complementary to expressed NATs revealed no significant change in mRNA levels, which suggests NAT expression may influence stress response through dsRNA formation or other RNA mediated mechanisms. These results establish a basis for further investigations into the connection between NATs and the stress response of fungi. Author Keywords: natural antisense transcripts, non-coding RNAs, stress response, Ustilago maydis
Does boredom lead to ego-depletion? Examining the association between boredom and ego-depletion
Ego-depletion refers to the observation that using self-control at Time 1 (T1) in the sequential-task paradigm leads to worse self-control at Time 2 (T2; Baumeister et al., 1998). Self-control is often manipulated by varying the difficulty of the task used at T1. Recently, Wolff and colleagues (2020) suggested that failures to replicate the ego-depletion phenomenon may arise because simple tasks may be boring, therefore requiring self-control to maintain attention on the task. Three experiments (Experiment 1, N=60; Experiment 2, N=61; Experiment 3, N=59) are reported that examined whether boredom at T1 predicted self-control at T2. A simple Go/No-Go task was used at T1. The ratio of Go to No-Go trials was changed across experiments to explore how the properties of the boring task impacted the association between boredom and self-control. When responding was frequent, increased boredom at T1 was associated with fewer anagrams correctly solved (Experiment 1 and 3), and more self-reported fatigue at T2 (Experiment 1), consistent with boredom leading to ego-depletion. However, when responding was infrequent (Experiment 2), increased boredom at T1 was associated with more correctly solved anagrams at T2, suggesting that the properties of a boring task change the psychological outcome that task has on self-control. Author Keywords: attention, boredom, ego-depletion, executive function, self-control
The Relations Between Identity Developmental Processes, Study Habits, and Academic Performance
Adolescence is a time when young people focus their attention on setting and pursuing long-term goals. Contemporary approaches of identity development focus on three pivotal processes underlying the identity formation process and the maintenance of one’s identity (e.g., core values, etc.). These processes are commitment (commitments to a goal), in-depth exploration (exploration of choices and options), and reconsideration of commitment (feelings of uncertainty about current commitments). The primary purpose of the current study was to examine the relations between identity processes, study habits, and academic performance in 45 female undergraduate students (M age = 21.00). Utilizing a self-report measure, findings suggested a significant positive relation between educational and relational commitment, as well as reconsideration of commitments in the educational domain and reconsideration of commitments in the relational domain. In terms of identity processes and grades, a regression analysis revealed that educational reconsideration of commitments predicted academic performance. Further, for those employing poor study habit skills, educational reconsideration of commitment predicted academic performance. The present study offers insight on the importance of assessing adolescent’s uncertainty of educational and relational commitments, while also highlighting the protective factor of maintaining good study habit strategies. Author Keywords: academic performance, adolescence, educational, identity, relational, study habits
On Forests, Witness Trees, and Bears
This dissertation is about Forests, their loss and the grieving that arises from their loss. The loss of ancient and old-growth forests by way of clearcutting and or anthropogenically driven disturbances, including climate change, presents the quandary of loss of both biological and cultural diversity. Following Umeek’s/E. Richard Atleo’s term, I suggest that “dis-ease” in the dominant relationship to forests in parts of the Western world significantly rests within inherited cultural and political pasts at play in the present, carried in much of the language and lifeways of modern Anglophone societies today. I do so by a critical topographical exploration of thematic patterns that go back to the Epic of Gilgamesh, the oldest written account of deforestation in the history of Western civilization. I offer at the center of my inquiry a collection of witness trees as North American case studies. Each tree is a witness object, a station from which I confront and explore social-ecological grief as it has accumulated over time from English colonization, with one focusing on Indigenous cultural reclamation and place-based ecological co-management. Lastly, I turn to a multispecies exploration of social-ecological grief, using bears in North America as a face for reflection and consider who and what more is lost when old forests are degraded and gone. By asking the place question—“what place is this?”—of forests, or the Forest Question, my dissertation is thus an exploration of the connection and responsibilities to other place-based human and other-than-human communities in a rapidly changing climate. Author Keywords: critical topography, environmental grief, forests, multispecies, social-ecological relations, witness trees
Impacts of Cover Crops on Soil Health, Soil Nitrogen Dynamics, and Cytokinin Profiles
In Ontario, the dominant cash crop rotations consist of soybean (SB), which is a leguminous crop grown in rotation with maize (MZ) and winter wheat (WW). In addition to these crops, some farmers integrate cover crops (CC) into crop rotation, especially during the fallow period and winter seasons, to reduce nitrogen (N) losses via nitrate (NO3-) leaching and emission of N2 and the greenhouse gas nitrous oxide (N2O). This thesis focused on understanding the impact of crop phases in a MZ-(SB-WW)-CC rotation on the abundance of N-cycling bacterial communities that mediate nitrification and denitrification pathways. In addition, the influence of CCs on soil cytokinin (CK) profiles, which are plant growth-promoting hormones, were studied in a greenhouse trial to assess their potential impacts when integrating CCs into crop rotations. In particular, the relationship between traditional soil health parameters and the soil CK profiles was studied to understand how CKs might reflect biotic interactions and soil vitality. Results indicate N fertilizer application mono ammonium phosphate (MAP) and starter N:P: K (24:6:24) during WW planting in fall largely supported nitrifying bacterial communities (amoA) and potentially contributed to NO3- leaching. Management of MZ, which included spring-applied MAP resulted in larger denitrifying (nirK) bacterial communities, increasing the potential risk of N-loss via emission of dinitrogen gas (N2) and greenhouse gas N2O. However, CC soils had significantly lower nirK than MZ, reflecting the importance of strong and deep root systems of CCs, which have a higher ability to scavenge the substrates for denitrifying communities (NO3-). This highlights the importance of growing CCs in reducing the potential risk for N-loss via leaching and denitrification. Additionally, in the greenhouse trial, the ability of CCs to affect CK was detected, highlighting the importance of integrating CC in crop rotations. This is particularly noteworthy, given that total CK profiles showed strong associations with traditional soil health parameters such as labile or active carbon and soil microbial community diversity. It was concluded that total soil CK can be used as a novel and dynamic soil health measure. Future research on quantifying N2O fluxes and levels of NO3- in leachates would provide a more precise understanding of the impact of different crop rotation phases on N-dynamics in these fields. Further studies on single or combined measures of soil CKs are warranted to develop its potential as a practical and effective soil health parameter. Author Keywords: Cover crops, Crop rotations, Cytokinin hormone, Nitrogen Cycle, qPCR, Soil health
Ripe for the Taking
This thesis considers the fanfiction genres of slash-fiction, and Alpha/Beta/Omega fiction through an analysis of fandom’s embedded gift economy structures. Previous research on fanfiction and fandom structures have often characterized the gift economy nature of these spaces as countercultural and as separate from the frequent exploitation inherent in economic-based systems. There has been less attention paid to considering the potential disruptions that can come with unregulated and large-scale sharing. This thesis undertakes a critical discourse analysis of Alpha/Beta/Omega slash-fiction with a focus on commodity fetishism to reveal how the subgenre’s relationship with the fanfiction gift economy complicates and at times counters the conception of these spaces as a ‘queer utopia.’ The purpose of this research is to dismantle traditional archetypes within Alpha/Beta/Omega fanfiction by exploring how male Omegan characters become fetishized cultural commodity objects internally through interactions with Alpha characters and externally through the desires of fanfiction readers and writers. Author Keywords: Alpha/Beta/Omega, Commodity Fetishism, Fanfiction, Gift Economy, Queer Theory, Slash-fiction
Nutrient Management in Forest Management Planning
This research evaluates the degree to which nutrients are included in forest management planning. First, the thesis evaluates forest management plans globally to determine the extent to which countries consider key nutrients (N, P, Ca, Mg and K) in their forest management plans. This is followed by a case study in Muskoka, Ontario, of a pilot wood ash recycling program with the goal of restoring calcium and other nutrients in the forests. This pilot project aims to evaluate the benefits of using wood ash as a forest fertilizer, as evidence that the practice merits approval by the provincial government. A text-based literature analysis of current regulations and the Environmental Compliance Approval (appendix 3) submitted to the provincial government for this project was undertaken as this project is currently a not approved practice by the government. Interviews were completed with key stakeholders and experts in the field to understand the benefits and policy hurdles of this program. Based on the documents analysed in this study, it was concluded that both globally and in Canada, nutrient management is not the focus of forest management plans. With respect to the pilot wood ash program, this thesis concluded that there is not enough data published to make the government departments comfortable with approving wood ash as a soil fertilizer. Nevertheless, there is much community support and many perceived benefits to this project, but more supporting data is needed. Author Keywords: Forest, Nutrients, Sustainability, Wood-ash
Uplifting Her Voice
This thesis creates an adaptation of act five, scene three of William Shakespeare’s Titus Andronicus that reshapes the play by focusing on female empowerment through the character Lavinia. Specifically, by using other Shakespearean characters’ dialogue that can speak towards her situation, I have written a monologue and stage directions for Lavinia. The same patriarchal superstructures which existed in the West during the time of Shakespeare and at the time of the play’s setting—and which still exist today—ensure that Lavinia remains silenced. Through my adaptation, I aim to challenge these structures in a meaningful way by returning both voice and agency to Lavinia. Author Keywords: Adaptation, Agency, Metamorphosis, Patriarchy, Revenge, Voice
Green Leadership in the Classroom
Concerns about climate change means that there is an urgent need to understand teachers’ role in educating students about environmental issues and sustainability. However, little is known about teachers’ environmental leadership and how that affects their competencies in the classroom, their general well-being and connections with nature, or what kinds of personality characteristics shape these teachers. A sample of current, future, and past Canadian teachers (N = 260) completed an online survey which included quantitative and qualitative questionnaires. Correlational and regression analyses determined teachers who possess environmental leadership qualities have a greater connection with nature, more positive well-being, and are more confident in their abilities to teach students outdoors. Furthermore, positive personality traits predict teachers’ environmental leadership. Qualitative data revealed both structural and psychological barriers reduced the likelihood of teachers taking students outdoors and that greater support, resources and training are needed to enable teachers to implement more nature-based learning. Author Keywords: competence, environmental leadership, nature relatedness, personality, teachers, well-being
Anishinaabemowin Teacher Perspectives of Indigenous Language Instruction in Nogojiwanong Public Schools
This thesis explores the importance of Indigenous languages and their revitalization, as well as the roles and responsibilities of schools through the perspective of Anishinaabemowin public school teachers in the Nogojiwanong, Peterborough ON, area. Three teachers were interviewed and have shared valuable insight into how they became teachers, how the language is taught in their schools, and the challenges associated with teaching these classes in these settings, as well as who should be learning and how these languages will bring us forward. From this information, recommendations for schools, school boards, and policy makers are included to better support instructors and students. Author Keywords: Anishinaabemowin, Indigenous, Indigenous Languages, Language Revitalization, Public Schools, Schools
Active layer thermal regime in subarctic wetlands at the southern edge of continuous permafrost in Canada
The fine-scale controls of active layer dynamics in the subarctic at the southern edge of continuous permafrost are currently poorly understood. The goal of this thesis was to understand how environmental conditions associated with upland tundra heath, open graminoid fen, and palsas/peat plateaus affected active layer thermal regime in a subarctic peatland in northern Canada. Indices of active layer thermal regime were derived from in-situ measurements of ground temperature and related to local measurements of air temperature, snow depth, and surface soil moisture. Active layer thaw patterns differed among landforms, with palsas and tundra heath having the least and greatest amount of thaw, respectively. Tundra heath thaw patterns were influenced by the presence of gravel and sandy soils, which had higher thermal conductivity than the mineral and organic soils of fens and palsas. Vegetation also influenced thaw patterns; the lichen cover of palsas better protected the landform from incoming solar radiation than the moss, lichen, and low-lying shrub cover of upland tundra heath, thus allowing for cooler ground temperatures. Air temperature was the most significant predictor of active layer thermal regime. Surface soil moisture varied among landforms and greater surface soil moisture reduced the amount of active layer thaw. These findings improved understanding of how landform and climate can interact to affect the active layer. Author Keywords: Active layer thermal regime, Active layer thickness, Climate change, Peatland, Permafrost, Subarctic
Deep learning for removal of non-resonant background in CARS hyperspectroscopy
In this work, a deep learning approach proposed by Valensise et al. [3] for extracting Raman resonant spectra from measured broadband CARS spectra was explored to see how effective it is at removing NRB from our experimentally measured “spectral-focusing”-based approach to CARS. A large dataset of realistic simulated CARS spectra was used to train a model capable of performing this spectral retrieval task. The non-resonant background shape used in creating the simulated CARS spectra was altered, to mimic our experimentally measured NRB response. Two models were trained: one using the original approach (Specnet) and one using the updated NRB “Specnet Plus”, and then tested their ability to retrieve the vibrationally resonant spectrum from simulated and measured CARS spectra. An error analysis was performed to compare the model's retrieval performance on two simulated CARS spectra. The modified model's mean squared error value was five and two times lower for the first and second simulated CARS spectra, respectively. Specnet Plus was found to be more effective at extracting the resonant signals. Finally, the NRB extraction abilities of both models are tested on two experimentally measured CARS hyperspectroscopy samples (starch and chitin), with the updated NRB model (Specnet Plus) outperforming the original Specnet model. These results suggest that tailoring the approach to reflect what we observe experimentally will improve our spectral analysis workflow and increase our imaging potential. Author Keywords:

Pages

Search Our Digital Collections

Query

Enabled Filters

  • (-) ≠ Morrison

Filter Results

Date

1974 - 2024
(decades)
Specify date range: Show
Format: 2024/04/24