Graduate Theses & Dissertations

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Evaluating Environmental DNA (eDNA) Detection of Invasive Water Soldier (Stratiotes Aloides)
In 2008, the first North American water soldier (Stratiotes aloides) population was discovered in the Trent River, Ontario. Water soldier is an invasive aquatic plant with sharp, serrated leaves that has the potential to spread rapidly through dispersed vegetative fragments. Although it is too late to prevent water soldier establishment in the Trent River, its local distribution remains limited. In this study, environmental DNA (eDNA) was explored as a potential tool for early detection of water soldier. Species-specific markers were designed from chloroplast DNA regions matK and rbcL, and a qPCR assay with rbcL primers yielded the most sensitive detection of water soldier eDNA. Positive detections were obtained from six of 40 sampling locations, of which five were collected in Seymour Lake, an area with large patches of water soldier. As water soldier plants were known to be present at these sites, high eDNA concentrations were expected. The sixth positive detection from Trent Lock 5 (50 km downstream of Lake Seymour) was unexpected as it was obtained at a site with no water soldier sightings. This is one of the first studies to demonstrate the effectiveness of eDNA detection from aquatic plants. Author Keywords: aquatic plant, eDNA, environmental DNA, invasive species, Stratiotes aloides, water soldier
Ritual, Social Organization, and Monumental Architecture
New archaeological material was discovered in 2006 by the Göksu Archaeological Project in an area of Southeastern Turkey known as Rough Cilicia. This thesis documents and explores the material remains from funerary contexts at the sites of Dağpazarı and Topkaya. Architectural analysis of the material from Dağpazarı demonstrates that the remains are of a monumental temple tomb dating to the late second or early third century A.D. Although the remains from Dağpazarı are fragmentary, the evidence is examined to suggest possible architectural reconstructions. The examination of the Topkaya tomb cluster sheds light upon an ornately decorated rock-cut temple façade tomb dating the Roman period. Both sets of tombs are stunning examples of monumental architecture from the Roman period in an area that suffers from a lack of surviving architectural material. In order to understand the variation in monumental tomb forms the relationship between death, burial, and monumental architecture is examined from a functional perspective. The rites of passage are used as a theoretical framework for examining the functional role that monumental architecture plays in the performance of funerary ritual and the formation of social organization in Roman Rough Cilicia. Ultimately, it is demonstrated that monumental funerary architecture serves as a physical manifestation of abstract concepts that aid in the performance of the rites of passage associated with death and the funeral. Thus, this thesis highlights how abstract information can be gained from seemingly limit physical remains. Author Keywords: Burial, Monumental Funerary Architecture, Rites of Passage, Roman, Rough Cilicia, Social Organization
Studies of the Giardia intestinalis trophozoite cell cycle
To study the Giardia intestinalis cell cycle, counterflow centrifugal elutriation (CCE) was used to separate an asynchronous trophozoite culture into fractions enriched for cells at the different stages of the cell cycle. For my first objective, I characterized the appearance of a third peak (Peak iii) in our flow cytometry analysis of the CCE fractions that initially suggested the presence of 16N cells that are either cysts or the result of endoreplication of Giardia trophozoites. I determined that this third peak consists of doublets of the 8N trophozoites at the G2 stage of the cell cycle that were not removed effectively by gating parameters used in the analysis of the flow cytometry data. In the second objective, I tested the use of a spike with RNA from the GS isolate of Giardia as an external normalizer in RT-qPCR on RNA from CCE fractions and encystation cultures of Giardia from the WB isolate. My results showed that the GS RNA spike is as effective as the use of previously characterized internal normalizer genes for these studies. For the third objective, I prepared two sets of elutriation samples for RNA seq analysis to determine the transcriptome of the Giardia trophozoite cell cycle. I confirmed the results of the cell cycle specific expression of several genes we had previously tested by RT-qPCR. Furthermore, our RNA-seq identified many genes in common with those identified from a microarray analysis of the Giardia cell cycle conducted by a collaborator. Finally, I observed an overall <4 fold change in differentially expressed genes during the G1/S and G2/M phase of the cell cycle. This is a modest change in gene expression compared to 10 - 30 fold changes for orthologous genes in mammalian cell cycles. Author Keywords: Cell cycle, Counterflow Centrifugal Elutriation, Flow Cytometry, RNA-sequencing, RT-qPCR
significance of topographically-focused groundwater recharge during winter and spring on the Oak Ridges Moraine, southern Ontario
The Oak Ridges Moraine (ORM) is a key hydrogeologic feature in southern Ontario. Previous work has emphasized the importance of depression-focused recharge (DFR) for the timing and location of groundwater recharge to the ORM’s aquifers. However, the significance of DFR has not been empirically demonstrated and the relative control of land cover, topography, and surficial geology on DFR is unclear. The potential for DFR was examined for topographic depressions under forested and open, agricultural land covers with similar soils and surficial geology. Recharge (R) was estimated at the crest and base of each depression during the 2012-13 and 2013-14 winter-spring periods (~December – May) using both a 1-dimensional water balance approach and a surface-applied Br- tracer. At each depression, air temperatures, precipitation, snow depth and water equivalent, soil water contents, soil freezing, and depression surface-water levels were monitored and soil properties (texture, bulk density, porosity, and hydraulic conductivity) were measured. Both forested and agricultural land covers experienced soil freezing; however, concrete frost did not develop in the more porous and conductive forest soils. Concrete frost in agricultural depressions resulted in overland flow, episodic ponding and drainage of rain-on-snow and snowmelt inputs. Recharge was an order-of-magnitude greater at the base of open depressions. Observations of ponding (as evidence of DFR) were made at an additional 14 depressions with varying land cover, geometry, and soil type during the 2014 snowmelt period and measurements of pond depth, pond volume, land cover (i.e., percentage of agricultural vs. forested cover), depression geometry (i.e., contributing area, average slope, relief ratio) and soil texture were made. Ponding was restricted to depressions under mostly agricultural cover and a positive, non-linear relationship between pond volume and average slope was shown for sites with similar land cover and soil texture, but neither pond depth nor volume were related to any other depression characteristics. Results suggest that DFR is a significant hydrologic process during winter and spring under agricultural land cover on the ORM. Topographic depressions under agricultural land cover on the ORM crest may serve as critical recharge “hot spots” during winter and spring, and the ability of the unsaturated zone beneath these depressions to modify the chemistry of recharging water deserves further attention. Author Keywords: Concrete frost, Depression-focused groundwater recharge, Oak Ridges Moraine, Ponding, Topographic depressions, Water balance
Civil Aviation and Scheduled Air Services in Colonial Botswana, 1935-1966
This thesis provides an in-depth and chronological study of the development of civil aviation in the Bechuanaland Protectorate (today’s Botswana), and the role played by the British Government in the development of this form of transport. The thesis argues that Her Majesty’s Government’s neglect and very little interest in its protectorate’s civil aviation represented a form of underdevelopment. The study also reveals the constant contradiction between the neglect of the imperial government and the constant lobbying on the part of colonial administration in the Protectorate for the establishment of an air service. To the colonial administrators, civil aviation represented a symbol of modernity and progress as well as more practical advantages such as mobility. The thesis finally concludes that the Bechuanaland Protectorate’s first airline was established due to growing nationalism both locally and on the continent, at large. The British Government facilitated the establishment of the airline as an attempt to appear benevolent to the protectorate on the eve of independence. Author Keywords:
Agro-Ecological Zoning (AEZ) of Southern Ontario and the Projected Shifts Caused by Climate Change in the Long-term Future
This thesis proposes an agro-ecological zoning (AEZ) methodology of southern Ontario for the characterization and mapping of agro-ecological zones during the historical term (1981-2010), and their shifts into the long-term (2041-2070) projected climate period. Agro-ecological zones are homogenous areas with a unique combination of climate, soil, and landscape features that are important for crop growth. Future climate variables were derived from Earth System Models (EMSs) using a high emission climate forcing scenario from the Intergovernmental Panel on Climate Change 5th Assessment Report. The spatiotemporal shifts in agro-ecological zones with projected climate change are analyzed using the changes to the length of growing period (LGP) and crop heat units (CHU), and their manifestation in agro-climatic zones (ACZ). There are significant increases to the LGP and CHU into the long-term future. Two historical ACZs exist in the long-term future, and have decreased in area and shifted northward from their historical locations. Author Keywords: Agro-climatic Zones, Agro-ecological Zones, Agro-ecological Zoning, Climate Change, Crop Heat Units, Length of Growing Period
'Land Displacement and Coping Strategies'
This thesis explores the social history of the Marange people of eastern Zimbabwe from the 1960s to 2015. It uses historical episodes like the recurring droughts, the 1970s war of independence, the ‘crisis in Zimbabwe,’ that has been traced from the late - 1990s, and the diamond mining story to demonstrate how the inhabitants interacted with their environment. It argues that the relocation project that began in 2010 had a severely disruptive impact on the families relocated to the relocation area - ARDA Transau - making the case that the Marange relocation project was a ‘development disaster.’ While the provision of accommodation had a notable positive impact on the majority of the displaced households, family needs were not always met. For instance, large families such as those of the dominant polygamous followers of the African Apostolic Church of Johanne Marange were not provided with adequate housing. Also, the livelihoods of the displaced households were shattered by the relocation exercise. In their efforts to creatively adapt to these new constraints, the displacees had diverse coping strategies like selling firewood, illegally extending space for crop cultivation, artisanal mining, vending and begging for food to eke out a living. Author Keywords: Coping Strategies, Crisis in Zimbabwe, Development, Displacement, Land, Livelihoods
How Do We Let the Players Play and Keep Them Safe? The Issue of Problematic Beliefs in the Prevention of Concussion Injury
Athletes’ concussion risk is part of a complex system of personal and contextual factors. This study differentiated athletes based on attitudes and intentions towards protective behaviours. A cross-sectional survey design was used to sample varsity athletes. Three intention response subgroups (indifferent, reactive, and proactive) were identified. The indifferent group (28%) reported little-to-no intent to engage in risk reduction behaviours. These athletes reported lower belief in the efficacy of concussion management behaviours and greater risk acceptance attitudes. The proactive group (32%) reported intent to actively reduce personal concussion risk through engaging in behaviours such as confronting aggressive opponents about the risk they pose to others. The reactive group (40%) only reported intent to engage in concussion management behaviours. Indifferent athletes had the highest likelihood of concussion exposure followed by reactive athletes. The proactive athletes had the lowest likelihood. Concussion programs must address beliefs and intentions towards protective behaviours to improve effectiveness. Author Keywords: Athlete, Attitudes, Concussion, Injury Prevention, Intentions, Risk
effects of in-stream woody debris from selective timber harvest on nutrient pools and dynamics within Precambrian Shield streams
Timber harvest can influence the rate of transfer of organic matter from the terrestrial catchment to streams, which may have both direct and indirect effects on in-stream nutrient pools and dynamics. In the interest of developing sustainable forestry practices, the continued study of the effects of forestry on nutrient dynamics in aquatic systems is paramount, particularly in sensitive nutrient-poor oligotrophic systems. The goal of this study was to investigate the impacts of harvest-related woody debris on stream nutrient status in streams located in the Canadian Shield region of south-central Ontario. Surveys showed greater large (> 10 cm) and small (< 10 cm) woody debris dry masses and associated nutrient pools in streams located in recently (2013) selectively harvested catchments, when compared with catchments not harvested for at least 20 years. Experimental releases of flagging tape underlined the importance of woody debris as a mechanism of coarse particulate organic matter (CPOM) retention. Sediment surveys showed a significant exponential decline in both OM content and nutrients associated with coarse sediment with distance upstream from debris dams. Laboratory leaching experiments suggest that fresh woody debris may be an important short-term source of water-soluble nutrients, particularly phosphorus and potassium. This study suggests that woody debris from timber harvest is both a direct and indirect source of nutrients, as trapped wood and leaves that accumulate behind debris dams can augment stream nutrient export over long time periods. Author Keywords: nutrient leaching, nutrient pools, organic matter retention, selection harvest, southern Ontario, woody debris
Controlling the Feminine Body in Public
Within this project, I have identified a new pattern of instruction, surrounding women’s bodies and their movement within the public space, present within didactic literature produced during the reign of Charles VI of France (1368-1422). This pattern, present in the texts Le livre du Chevalier de la Tour Landry pour l’instruction de ses filles, Le Menagier de Paris, Le livre des trois vertus and Mirroir des dames, sought to shame control women’s physical presentation in public through use of imagery, stories and fear of pride. Using modern gendered body theory presented by Luce Irigaray and Judith Butler to examine the rise of this pattern, this project then concludes it represents an attempt of the social authority to present a passive feminine body in the public space in order to display male power during a time of social instability. Author Keywords: body history, didactic literature, medieval education, medieval France, women, women's bodies
Disability-Mitigating Effects of Education on Post-Injury Employment Dynamics
Using data drawn from the Workplace Safety and Insurance Board’s (WSIB) Survey of Workers with Permanent Impairments, this thesis explores if and how the human capital associated with education mitigates the realized work-disabling effects of permanent physical injury. Using Cater’s (2000) model of post-injury adaptive behaviour and employment dynamics as the structural, theoretical, and interpretative framework, this thesis jointly studies, by injury type, the effects of education on both the post-injury probability of transitioning from non-employment into employment and the post-injury probability of remaining in employment once employed. The results generally show that, for a given injury type, other things being equal, higher levels of education are associated with higher probabilities of both obtaining and sustaining employment. Author Keywords: permanent impairment, permanent injury, post-injury employment
Investigating wheat rust virulence evolution through transcriptome analysis of a recently emerged race of Puccinia triticina
Puccinia triticina, wheat leaf rust (WLR), is the most economically damaging fungal rust of wheat on a global scale. This study identified transcriptome changes in a recently emerged race of WLR in Ontario with a new virulence type relative to a possible ancestor race. Also, this study focused on detecting variation in candidate virulence genes and uncovering novel insight into WLR virulence evolution. Various race-by-variety interactions were evaluated using RNA-seq experiments. A list of genes with statistically significant expression changes in each comparison was prepared and predicted effectors were retained for further analysis. Proteins with nonsynonymous substitutions were run through BLASTx to identify potential orthologs. Over 100 candidate effectors with a 2-fold or higher change in transcript level were identified. Seven of these candidate effector genes were recognized to contain single nucleotide polymorphisms (SNPs) which altered the amino acid sequence of the resulting protein. The information gained may aid in targeted breeding programs to combat new WLR races as well as provide the basis for functional analysis of WLR using potential orthologs in a model basidiomycete. Author Keywords: effectors, RNA-seq, rust fungi, SNPs, transcriptome, wheat leaf rust

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Graduate student theses produced at Trent University. You may also browse theses and dissertations by year, program, or author.

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