Graduate Theses & Dissertations

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Combining Line Transect Sampling and Photographic-Identification Surveys to Investigate the Abundance and Distribution of Cetaceans
Line transect sampling and photographic-identification (photo-ID) are common survey techniques for estimating the abundance and distribution of cetaceans. Combining these approaches in the field (‘combined LTPI’ surveys) and using data from both components has the potential for generating comprehensive ecological knowledge that can be far more valuable than when these techniques and their data are used independently. In this thesis, I evaluated the results and conclusions from these two methods, used singly and in tandem, by investigating the population dynamics of two humpback dolphin (Sousa chinensis spp.) populations: the large and widely distributed Chinese white dolphin (S. c. chinensis) of the Pearl River estuary (PRE), and the small and geographically isolated subspecies of Taiwanese white dolphin (S. c. taiwanensis) in the eastern Taiwan Strait. Data from combined LTPI surveys in Hong Kong waters, at the eastern edge of the PRE, revealed a shift in space use with individuals spending less time in these waters than at the start of surveys. Data from combined LTPI surveys in Taiwan provided further support for a subspecies restricted to the central western waters, and identified a commonly used area at the northern part of their limited range. These two case studies demonstrated an overall efficacy of combined LTPI surveys in ecological studies of cetaceans. However, a multi-criteria analysis revealed that combined LTPI surveys with a line transect focus (e.g., Hong Kong) performed better than a LTPI survey with a photo-ID focus (e.g., Taiwan) when considering ecological aspects of the study populations, labour and data requirements, and ecological output. Even so, the photo-ID focus of Taiwan’s monitoring program led to better assessments of individual space use patterns, likely helped by the Taiwanese white dolphin population’s smaller size and intensive photographic effort. In both cases, the ecological output of combined LTPI surveys could be improved by expanding the study area or extending the field season or frequency of surveys. Overall, I showed that by following a set of general guidelines, different iterations of the combined LTPI approach (i.e., photo-ID focus or LT focus) can serve as powerful tools for uncovering multi-dimensional ecological information on cetaceans. Author Keywords: abundance, cetacean, distribution, line transect sampling, multi-criteria analysis, Photo-ID
Biodiversity patterns along a forest time series in a remediated industrial landscape
Sudbury, Ontario is an epicenter of research on industrially degraded landscapes. Regreening efforts over the past 40 years have changed the landscape, leading to an increase in forest cover in the “barrens”, that once covered more than 100,000 ha. This study characterized changes in plant and insect composition using a space for time approach in the pine plantations. A total of 25 treated sites were sampled and soil characteristics, understory plants and insect communities were assessed. All sites were contaminated with copper and nickel, but the metals had little influence on biodiversity. Vegetation diversity metrics were more strongly correlated with the pH of the organic soil horizons, while the insect community shows little response to site characteristics, and rather vegetation cover. Plant composition changes are similar to those in pine stands undergoing natural recovery and as liming effects fade there may be a decline in insect community richness. Author Keywords: Biodiversity, Heavy Metals, Mining, Remediation
Endocannabinoid Treatment for the Behavioural and Histopathological Alterations of Epilepsy
Epilepsy is associated with a variety of cognitive, emotional, and pain-related symptoms, such as impaired memory and learning, increased risk of anxiety and depression, and increased pain sensitivity. Unfortunately, these symptoms are generally untreated with typical pharmacological interventions, which tend to target seizure activity (i.e., ictogenesis) and not the subsequent histopathological and behavioural alterations resulting from epilepsy (i.e., epileptogenesis). Evidence has demonstrated that targeting the endocannabinoid system can alleviate seizure symptoms as well as cognitive, emotional, and pain-related impairments independent of epilepsy. However, research examining the use of endocannabinoid-based treatment for these behavioural symptoms when they are associated with epilepsy is sparse. In the following thesis, two animal models of epilepsy, several behavioural assessments, and immunohistochemical techniques are utilized to assess the effectiveness of endocannabinoid-based treatment for epilepsy’s interictal symptoms. The findings expand our knowledge and offer encouraging evidence for the usefulness of endocannabinoid-based treatment as an epileptogenesis-targeting pharmacological intervention. Author Keywords: animal models, endocannabinoid system, histopathological alterations, interictal symptoms, temporal lobe epilepsy, treatment
Unbridled Potential
Recently, equine assisted learning (EAL) has emerged as a novel approach to building resiliency competencies in at-risk youth. This mixed-methods study presents evaluation results for an 8-week community-based EAL program with 83 young women (age 13-18 years) with a history of interpersonal trauma. Analyses examined changes in self-reported mental health symptoms (posttraumatic, depression) and resiliency factors (sense of mastery, sense of relatedness, emotion regulation) from pre- to post-test and at 1-month and 6-month follow-ups. Changes in outcomes were also correlated with intervention processes (attendance, session ratings) to see if program experiences were associated with differential outcomes. Results showed that EAL has potential in improving resiliency outcomes, at least for those participants who derived greater satisfaction and value from the sessions. Many improvements were sustained over the long term. Participants’ qualitative feedback provided insight into their subjective experiences and highlighted the unique role that horses played in the EAL process. Author Keywords: Emotion Regulation, Equine Assisted Learning, Experiential Learning, Resilience, Sense of Mastery, Sense of Relatedness
Capital Ratios and Liquidity Creation
Using quarterly data from the six largest Canadian banks, we investigate the relationship between regulatory capital ratio and on-balance sheet liquidity created in the Canadian economy by “Big Six”. We find a significant positive relationship between Tier 1 capital ratio and on-balance sheet liquidity creation for Canadian big six banks, implying that large banks in Canada favor risks and rely on capital to fund illiquid assets. In contrast, for smaller banks, the relationship is significantly negative. Our results are robust to dynamic panel regression using 2-Step GMM, two exogenous shocks - COVID-19 crisis and the Global Financial Crisis (2007-2009), mergers & acquisitions activities in the banking industry, and core deposits financing. The COVID-19 pandemic and core deposits adversely impact the Tier 1 capital ratio’s relationship with on-balance-sheet liquidity creation, while the global financial crisis (2007-2009) effect on the association is insignificant. Author Keywords: Big Six, COVID -19, Deposits, Liquidity Creation, Tier 1 Capital Ratio,
Immunotherapies Targeting the Amyotrophic Lateral Sclerosis-Associated Protein TDP-43
Transactive response (TAR) DNA-binding protein of 43 kDa (TDP-43) pathology, including fibrillar aggregates and mutations, develops in amyotrophic lateral sclerosis (ALS) and is characterized by hyperphosphorylation and aggregation patterns, a mechanism largely understudied. In addition, ALS remains without a cure. Herein, in vitro aggregation of phosphorylated TDP-43 was explored, and the anti-TDP-43 antibodies tested for their inhibitor efficacies. Additionally, in vitro phosphorylation of TDP-43 by protein kinases was conducted to identify which protein kinases catalyze phosphorylation. The aggregation of phosphorylated and unphosphorylated full-length TDP-43 protein (pS410) was monitored by transmission electron microscopy (TEM), turbidity absorbance, and thioflavin (ThT) fluorescence spectroscopy. The protein aggregates were largely insoluble, ThT-positive and characterized with heterogeneous morphologies. Antibodies specific to epitopes within the RNA-recognition motifs and the C-terminal domains reduced the formation of β-sheets and insoluble aggregates, with outcomes highly dependent on the type of antibodies, indicating dual functionality. The only protein kinase able to phosphorylate TDP-43 at S410 was MARK4, indicating its role in the onset of PTMs in the protein. Thus, targeting TDP-43 epitopes for inhibition of aggregation and in vitro phosphorylation represent viable biochemical assays for screening protein kinase inhibitors as potential drugs against ALS. Author Keywords: aggregation, ALS, antibody-based inhibition, phosphorylation, protein kinase, TDP-43
Demographic history and conservation genomics of caribou (Rangifer tarandus) in Québec
Genetic variation is the raw material and basis for evolutionary changes in nature. The loss of genetic diversity is a challenge many species are facing, with genomics being a potential tool to inform and prioritize decision making. Whole genome analysis can be an asset to conservation biology and the management of species through the generation of more precise and novel metrics. This thesis uses whole genome re-sequencing to characterize the demographic history and quantify genomic metrics relevant to conservation of caribou (Rangifer tarandus) in Québec, Canada. We calculated the ancestral and contemporary patterns of genomic diversity of five representative caribou populations and applied a comparative population genomics framework to assess the interplay between demographic events and genomic diversity. When compared to the census size, NC, the endangered Gaspésie Mountain caribou population had the highest ancestral Ne:NC ratio which is consistent with recent work suggesting high ancestral Ne:NC is of conservation concern. These ratios were highly correlated with genomic signatures (i.e. Tajima’s D) of recent population declines and explicit demographic model parameters. Values of contemporary Ne, estimated from linkage-disequilibrium showed Gaspêsie having among the highest contemporary Ne:NC ratio. Importantly, classic conservation genetics theory would predict this population to be of less concern based off this metric alone. Inbreeding measures suggested nuanced patterns of inbreeding and correlated to the demographic models. This study suggests that while the Québec populations are all under decline, they harbour enough ancestral genetic variation to replenish any lost diversity, if conservation decisions are made in favour of these populations, specifically supporting NC. Author Keywords:
Frequency-time and polarization considerations in spectral-focusing-based CARS microscopy
Spectral-focusing-based coherent anti-Stokes Raman scattering (SF-CARS) microscopy is a powerful imaging technique that involves temporally and spectrally stretching ultrashort laser pulses and controlling their frequency-time characteristics. However, a broader and more detailed understanding of the frequency-time characteristics of the laser pulses and signals involved, how they are related, and how they influence important aspects such as the spectral resolution is needed to understand the full potential of SF-CARS systems. In this work, I elucidate these relationships and discuss how they can be exploited to optimize SF-CARS microscopy setups. I present a theoretical analysis of the relationships between the spectral resolution, the degree of chirp-matching, and pulse bandwidth in SF-CARS. I find that, despite allowing better ultimate spectral resolution when chirp-matching is attained, the use of the broadest bandwidth pulses can significantly worsen the spectral resolution if the pulses are not chirp-matched. I demonstrate that the bandwidth of the detected anti-Stokes signal is minimized when the pump is twice as chirped as the Stokes, meaning that (perhaps counter-intuitively) a narrow anti-Stokes bandwidth does not imply good spectral resolution. I present approximate expressions that relate the bandwidths of the pump, Stokes, and anti-Stokes pulses to the degree of chirp-matching and outline how these could be used to estimate the amount of glass needed to attain chirp-matching. I develop a spectral-focusing-based polarization-resolved (SFP-CARS) setup, by modifying our existing system, to explore the merits of integrating polarization-dependent detection as an add-on to existing SF-CARS setups. By using the system to study polarization-dependent features in the CARS spectrum of benzonitrile, I assess its capabilities and demonstrate its ability to accurately determine Raman depolarization ratios. Ultimately, the detected anti-Stokes signals are more elliptically polarized than desired, hindering a complete suppression of the non-resonant background. Nevertheless, I find that the SFP-CARS setup is a useful tool for studying polarization-dependent features in the CARS spectra of various samples and is worthy of further investigation. This work clarifies several technical aspects of SF-CARS microscopy and provides researchers with valuable information to consider when working with SF-CARS microscopy systems. Author Keywords: coherent anti-Stokes Raman scattering, nonlinear microscopy, polarization, spectral focusing, spectroscopy
Experiencing buhts’an qu’inal from sHachel jwohc’ a’tel through sna'el ya'beyel stuc te bin ay ma'yuc
This thesis shows and emphasizes the importance of Indigenous Knowledge (IK) in informing collaborative efforts that promote sustainable economic development in Indigenous communities. It tells the story of a participative research study undertaken with six Tseltal communities located in the Region Selva of Chiapas, Mexico, in the context of the Covid19 pandemic of 2020 and early 2021. In this study, the research participants reflect on their endeavours pursuing projects focused on the economic self-sufficiency of their communities. Their initiatives, which are deeply grounded in Tseltal practices while accompanied by the local non-profit organization IXIM AC, focus on developing economically self-sustaining enterprises in self-organized groups led by local Indigenous women. The findings offer a deep immersion into two aspects that emerge from Tseltal knowledge: The Nucleus of Tseltal community wellbeing and the Four Elements of Buhts’an qu’inal (Tseltal community wellbeing). The study’s results show that these two IK grounded aspects guide the participants’ endeavours in developing sHachel jwohc’ a’tel (Tseltal initiatives of entrepreneurship) while also enabling opportunities for gender transformative collaborative work and sustained engagement in local initiatives of sna'el ya'beyel stuc te bin ay ma'yuc (Tseltal economic development oriented to community wellbeing). Author Keywords: Community Wellbeing, Indigenous Entrepreneurship, Indigenous Knowledges, Indigenous Women, Participative Action Research, Sustainable Development
Evidence for hybrid breakdown in the cattail (Typha) hybrid swarm in southern Ontario
Heterosis, expressed as phenotypic superiority over parental species, typically peaks in first generation hybrids (F1s), while later generations (F2 +) exhibit lower fitness. The decrease in hybrid fitness is called hybrid breakdown. The overall incidence of hybrid breakdown in invasive hybrid zones remains poorly understood. The Laurentian Great Lakes (LGL) region contains a hybrid zone comprised of: native Typha latifolia, Typha angustifolia, and hybrid Typha × glauca. F1 T. × glauca display heterosis and are invasive, while later generation hybrids are relatively rare. To investigate possible hybrid breakdown, I compared seed germination and plant growth of backcrossed and advanced-generation (F2) hybrids to F1s and T. latifolia. I found evidence for hybrid breakdown in F2s and backcrossed hybrids, expressed as reduced growth and germination rates. Expression of hybrid breakdown in F2s and backcrosses may explain their relative rarity in the LGL hybrid zone. Author Keywords: Advanced-generation hybrids, Backcrossed hybrids, Hybridization, introgression, Invasive species, plant competition
Forging Masks Through Perceptions of the Maskless in Benjamin Britten’s 'Peter Grimes'
This thesis proposes that Benjamin Britten’s 'Peter Grimes' leads its audience toward actively constructing an attitude toward its maskless protagonist. Grimes’s tragedy results from the social construction of his character from ambiguous and unseen actions. Utilizing the theories of Hannah Arendt and Carl Jung, this thesis proposes that Grimes may have resisted tragedy by constructing a public persona for himself. This thesis analyses the opera’s music and narrative according to the difference between Grimes’s lack of a public persona and the Borough- members’ construction of a mask for him. A central contention of the thesis is that as another element of Britten’s persona, Peter Grimes permitted the composer’s entrance into the public sphere, despite his private inclinations and illegal sexuality. Like the opera’s drama, the opera’s “Sea Interludes” reveals the tragedy resulting from the failure to construct an attitude toward the public world. These “Sea Interludes” work alongside the opera’s drama to induce the audience into a common perception of the opera’s whole. Through ironic relation to the opera’s musical and narrative parts, Benjamin Britten induces his audience’s construction of personae, thereby bringing himself and them into a shared public realm. Author Keywords: Benjamin Britten, E. M. Forster, English Opera, Montagu Slater, Peter Grimes, W. H. Auden
evolutionary ecology of Alaska's mountain goats with management implications
The integration of genetic and environmental information can help wildlife managers better understand the factors affecting a species’ population structure and their response to disturbance. This thesis uses genetic techniques to assess the broad and fine scale population structure of mountain goats in Alaska. The first chapter aims to determine the number of genetically distinct subpopulations and model the demographic history of mountain goats in Alaska. The second chapter investigates the population structure and demographic history of mountain goats in Glacier Bay National Park and examines the impact that climate change will have on these mountain goats. My results indicate that Alaska has eight subpopulations which diverged during the Wisconsin glaciation. In Glacier Bay, population structure is reflective of the landscape during colonization, and mountain goat population density and movement corridors are likely to decline due to future climate change. Author Keywords: Alaska, biogeography, gene flow, landscape genetics, mountain goat, population genetic structure

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Format: 2024/03/04