Graduate Theses & Dissertations

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Differential expression of cytochrome b5s in Giardia intestinalis during nitrosative stress and encystation
The waterborne protozoan Giardia intestinalis cycles between the environmentally-resistant and infectious cyst and the metabolically-active trophozoite that adheres to the epithelial lining of the small intestine. Adhesion can trigger the innate immune response in epithelial cells, including the synthesis of the free radical nitric oxide (NO) that inhibits cell proliferation and encystation of trophozoites. In this work changes in protein expression of three Giardia isotypes of the redox heme protein cytochrome b5 (gCYTb5 I, II and III) were studied in response to either nitrosative stress or induction of encystation. Two nitrosative stressors, sodium nitrite and the NO donor DETA-NONOate, were used at sub-lethal concentrations (0.5 mM and 0.05 mM, respectively) that do not affect cell proliferation until later time points so that subtle changes in protein expression could be observed in the absence of other confounding factors. Nucleolar gCYTb5-I and nucleoplasmic gCYTb5-III expression patterns were similar in trophozoites exposed to either stressor, showing gradual increases in expression with peaks between 4 and 12 hours, which indicates these cytochromes respond to nitrosative stress and possibly to potential DNA damage in Giardia. In contrast, gCYTb5-II of the peripheral vacuoles, which are part of the endocytic pathway of Giardia, showed little change in expression in response to either stressor. However, changes in gCYTb5-II expression were observed in encysting trophozoites, with a 1.4-fold increase in protein levels at seven hours after induction of encystation, followed by a gradual decrease in expression. These changes are consistent with previous mRNA analysis done in our laboratory and suggest a role for gCYTb5-II in the increase in nutrient uptake during early encystation. Author Keywords: cytochrome, encystation, Giardia, heme, nitrosative, parasite
Creation During Abandonment
This thesis addresses the excavation and analysis of the Hingston Group, a small courtyard group just south of the ceremonial core of the Ancient Maya city of Ka’kabish in North-Central Belize. I use settlement and household archaeological theory to understand the functions, occupation history, and status of this residential group. I also rely on entanglement theory, along with the hypothesizes presented by Palka (2003) and McAnany (1995), to create a possible interpretation for the reasons why we see what we do in the Hingston Group during its main period of occupation. The Hingston Group is composed of three structures and two chultuns (underground storage areas). Research teams excavated both chultuns during prior field seasons and found burials from the Postclassic and Late Formative Periods. This information led to the assumption that the occupation of these structures would correspond to one, or both, of these periods. However, we found that this courtyard group was occupied during a period when the rest of the core of Ka’kabish was abandoned. Along with this, excavators found an ephemeral occupation into the Colonial Period; these two new periods of occupation have expanded our understanding of the chronological history of Ka’kabish. Author Keywords: formative to postclassic, household archaeology, Maya, settlement archaeology
Prioritizing Restoration Potential within Protected Areas in Haliburton County, Ontario
Ecological restoration helps managers of protected areas respond to challenges presented by factors that threaten ecological integrity and respond to residual effects of previous land use. Many protected areas require restoration on sections of the property, due to previous land use. The objective of this thesis is to present criteria that assist ecological restoration professionals in assessing the potential of restoration projects within a protected area, based on the restoration wheels from the International Principles and Standards for the Practice of Ecological Restoration. The criteria were discovered from a review of the literature and reinforced from interviews with experienced restoration practitioners and a focus group session with key members of the Haliburton Highlands Land Trust (HHLT). Based on the combination of biophysical and socioeconomic values in the restoration wheels, they are presented in the form of a five-star assessment system to create long-term restoration goals for properties of the HHLT and protected areas in general. These long-term restoration goals can be utilized in conjunction with the wheels and five-star assessment tools to prioritize restoration projects Author Keywords: Determining Project Potential, Ecological Restoration, Evaluating Success, Haliburton, Land trusts, Restoration Wheels
Assessment of Potential Threats to Eastern Flowering Dogwood (Cornus florida) in Southern Ontario
In Canada, eastern flowering dogwood (Cornus florida L.) is an endangered tree that occurs only in the Carolinian forest of southern Ontario. Threats to this species include habitat fragmentation and the fungal pathogen dogwood anthracnose (Discula destructiva). I conducted a population genetic analysis using seven nuclear microsatellite markers to determine if fragmented populations are genetically isolated from one another and have low levels of genetic diversity. Genetic comparisons suggest on-going dispersal among sites and relatively high genetic diversity within most sites; however, smaller populations and younger trees were less genetically diverse. I also used linear mixed effects models to assess potential relationships between several ecological variables and the prevalence of dogwood anthracnose. Disease severity was higher in trees on shallow slopes and in larger trees; the latter also had higher likelihood of infection. Insights from this study will be important to incorporate into future management strategies. Author Keywords: Cornus florida, Discula destructiva, dogwood anthracnose, Eastern flowering dogwood, endangered, population genetics
Civic Agriculture
This thesis re-imagines the social sustainability of civic agriculture. This entails critically examining the idea of sustainability and exposing why a tendency to undertheorize its social dimension is problematic for how we think about sustainability, and consequently for how we do sustainability. What is demonstrated is that we can overcome this tendency by adopting Stephen McKenzie's understanding of social sustainability as a positive condition and/or process within a community. Once brought into contact with the concept of civic agriculture as presented by Thomas A. Lyson, and expanded upon by others, this broadened understanding of social sustainability reveals that we can think of civic agriculture as both a means to, and an expression of, social sustainability. Specifically, this thesis argues that it is civic agriculture's community problem-solving dimension which animates civic agriculture in such a way that it creates the sort of condition and/or enables the sort of process which reflect aspects associated with a substantive and/or procedural understanding of social sustainability. This re-imagining of the social sustainability of civic agriculture provides ways to defend civic agriculture from its critics and is exemplified by drawing from a personal encounter with civic agriculture. In the end, it is proposed that in light of this research there are now good reasons to re-examine civic agriculture and to critically re-imagine what qualifies who as a civic agriculturalist so that the contextual nature of the social sustainability of civic agriculture can be better respected. Author Keywords: civic agriculture, community problem solving, local food systems, social sustainability, Stephen McKenzie, Thomas A. Lyson
Development of a Cross-Platform Solution for Calculating Certified Emission Reduction Credits in Forestry Projects under the Kyoto Protocol of the UNFCCC
This thesis presents an exploration of the requirements for and development of a software tool to calculate Certified Emission Reduction (CERs) credits for afforestation and reforestation projects conducted under the Clean Development Mechanism (CDM). We examine the relevant methodologies and tools to determine what is required to create a software package that can support a wide variety of projects involving a large variety of data and computations. During the requirements gathering, it was determined that the software package developed would need to support the ability to enter and edit equations at runtime. To create the software we used Java for the programming language, an H2 database to store our data, and an XML file to store our configuration settings. Through these choices, we can build a cross-platform software solution for the purpose outlined above. The end result is a versatile software tool through which users can create and customize projects to meet their unique needs as well as utilize the features provided to streamline the management of their CDM projects. Author Keywords: Carbon Emissions, Climate Change, Forests, Java, UNFCCC, XML
Signalling Beliefs in Ogilby's AFRICA
This study analyzes Christian European perceptions of group identity and beliefs in early modern geographic literature, as exemplified by John Ogilby’s Africa (1670), a selective translation of Olfert Dapper’s 1668 work, and its descriptions of West-Central Africa. Ogilby’s work, congruently with contemporary geographic literature, employed the Christian religion as a key marker of group identity, using it as a lens to interpret and define the collective identities of African societies it described. Using a theoretical framework derived from Daniel Bar-Tal’s Group Beliefs, the thesis demonstrates that Africa portrayed the officially Christian kingdom of Kongo as superior to its non-Christian neighbours, consistently represented in a negative light. This attitude reflected normative European beliefs of Christian superiority fanned by the period’s intense denominationalism and religious anxiety. Africa’s general ecumenism towards other Christian denominations and its maintained “othering” of non-Christian Africans was closely linked to Ogilby’s own sense of self-identity and group beliefs shaped by his life experiences in the seventeenth-century British Isles. Author Keywords: Africa, Christianity, Identity, Kongo, Ogilby, Syncretism
Ecosystem Response to Above Canopy Nitrogen Addition in a Jack Pine (Pinus banksiana) Forest in the Athabasca Bituminous Sands Region of Northeastern Alberta, Canada
In this study we seek to better understand the potential effects of short-term (5-year) N fertilization on jack pine forest biogeochemistry, vascular plant community composition and to project a temporal endpoint of nitrogen leaching below the major rooting zone. Aqueous ammonium nitrate (NH4NO3) was applied above the forest canopy across five treatment plots (20 x 80 m) four times annually. The experimental deposition gradient followed those known for localized areas around the major open pit operations at 0, 5, 10, 15, 20 and 25 kg N ha-1 yr-1 over a five-year period (2011 – 2015). Nitrate recovery in throughfall was significantly higher than NH4+ (p < 0.05), indicating canopy NH4+ immobilization. There was a strong treatment effect (p < 0.05) of N on the epiphytic lichen thalli concentrations of Hypogymnia physodes and Evernia mesomorpha after five years. The canopy appeared to approach saturation at the highest deposition load (25 kg N ha-1 yr-1) during the fifth year of N additions as most N added above the canopy was accounted for in throughfall and stemflow. The non-vascular (lichen and moss) vegetation pool above the forest floor was the largest receptor of N as cryptogam foliar and thalli N concentrations showed a significant treatment effect (p < 0.05). Nitrogen in decomposing litter (25 kg N ha-1 yr-1) remained immobilized after five years, while treatments ≤ 20 kg N ha-1 yr-1 started to mobilize. Understory vascular plant cover expansion was muted when deposition was ≥ 10 kg N ha-1 yr-1. Finally, modeling suggests the forest may not leach N below the rooting zone until around 50 years after chronic addition begin (25 kg N ha-1 yr-1). The modeling results are consistent with empirical data from a high exposure (~20 - 25 kg N ha-1 yr-1) jack pine site approximately 12 km west of the experimental site that has not yet experienced N leaching. Author Keywords: Biogeochemistry, Canopy, Deposition, Jack Pine, Nitrogen, Understory
Building social connections
This thesis evaluates a multi-stakeholder participatory planning initiative, NeighbourPLAN, in Peterborough, Ontario, and the role of the third-party broker, GreenUP, in establishing connections and networks of capacity between marginalized members of the community and contributing organizations, city, and experts. Participatory approaches to engage residents disenfranchised by traditional planning processes are believed to challenge the status quo perpetuated by top-down decision-making. I worked within two neighbourhoods involved in NeighbourPLAN to determine whether the collaborative work and brokering between stakeholders would foster increased connectedness that could exist independently and last beyond the project's timeline. The findings from this evaluation determine that, from the residents' perspectives, while the presence of the other stakeholders in these participatory planning events was valuable, there was not enough affective time to create long-lasting connections. Partners that developed relationships marked with trust and mutual benefit provide a helpful blueprint showing how serious commitment and consistency can build sustainable and meaningful connections. I conclude with a set of recommendations to enhance the connection building between diverse stakeholders and marginalized communities within NeighbourPLAN, highlighting the promising potential of arts-based and storytelling methods. Author Keywords: arts-based methods, community engagement, Participatory action research (PAR), participatory planning, photovoice, social connectedness
Tools and Techniques
The tools and techniques used by Ontario’s Middle Woodland potters to create designs on vessels have often been assumed in the literature. Pottery typologies currently use these assumptions to classify ceramics found in the archaeological record. Assumed, or suggested, tools and techniques include cord impression, cord-wrapped stick, fabric impression, fabric-wrapped paddle, incised paddles, unmodified shell, modified shell dentate tools, and leather thong. This thesis presents a series of experiments using replica versions of these tools. The results reveal that they are all viable tools for creating designs during ceramic manufacture. Specifically, incised paddles may have been used to create check-stamped pottery, unmodified shell may have been to create what the literature calls pseudo-scallop shell impressions, and modified shell may have been used to create what the literature calls dentate impressions. Where possible, experimental tiles were compared with examples from the Charleston Lake collection of complete to near complete Middle and Late Woodland vessels from Southeastern Ontario. These comparisons have revealed problems in the current classification and study of the Charleston Lake collection and a need for a re-evaluation of the current typologies used to classify Middle Woodland pottery Author Keywords: ceramic manufacture, cord-wrapped stick, experimental archaeology, Middle Woodland, point peninsula, pseudo scallop shell
Phosphorus delivery in the Rainy-River Lake of the Woods Watershed
Lake of the Woods (LOW) is a large international waterbody which suffers from frequent and widespread algae blooms. Previous studies have highlighted the importance of the lake's largest tributary, the Rainy River (RR) and its significance in total phosphorus (TP) delivery to the LOW. Unfortunately, little is known about TP contributions from the RR and its tributaries within the Canadian portion of the watershed. This thesis examines patterns and sources of TP from four tributaries on the Canadian side of the lower RR region, two of which are predominantly natural, and two that are predominantly agricultural. Relationships between water quality parameters, land use and geologic characteristics were observed over a complete hydrologic year (Oct 1, 2018 - Sept 31, 2019), and through an intensive sampling campaign using a nested watershed approach during the spring high flow and summer low flow periods. Results revealed that TP and total suspended sediment (TSS) concentrations (>100 µg/L and >20 mg/L respectively), and loads (>20 kg/km2 and >3500 kg/km2, respectively), were greater at agricultural sites compared with natural sites (<65 µg/L TP and <15 mg/L TSS concentration, and <20 kg/km2 TP and <4000 kg/km2 TSS export). Total P, TSS, Fe, and Al were significantly positively correlated (R2= 0.26-0.59; p<0.05) and intensive sampling revealed that these relationships were strongest during the spring and at the agricultural sites (R2= 0.73-0.98; p<0.05). In contrast, the summer intensive sampling revealed that TP and redox sensitive Fe were significantly correlated (R2= 0.72; p<0.005), whereas redox insensitive Al and TSS were not, suggesting TP may be sourced via redox processes in the summer due to favourable hydrologic conditions. This was observed not only at sites with high wetland influence, but also at sites with more agricultural presence suggesting that redox sourced TP may also originate from mineral stream bed sediment during low flow periods. This research suggested two primary TP sources in the lower RR region: erosion in the spring, and redox processes (internal release) in the summer. It is recommended that intensive monitoring continue in Canada, and further research be conducted to fully understand the significance of internal P release in the tributaries. Author Keywords: erosion, land use, nutrients, particulates, redox, water quality
After the Ash Fall
Mount Mazama, a large volcano located in the Cascade Range of Oregon, eruptedsome 7,000 cal. years BP. Following the volcanic eruption, a large portion of the northwestern region of the Great Plains of North America was covered by a thick layer of volcanic ash. The present research project is concerned with the impact of this catastrophic event on the subsistence patterns of the northwestern Plains groups during the early Archaic period (ca. 6,600–6,000 BP). More specifically, this research project tests the hypothesis that the eruption of Mount Mazama prompted the adoption of bone grease rendering in this part of the Plains. To test this hypothesis, a faunal analysis of the assemblages of Stampede site, located on the Cypress Hills of southeastern Alberta, was performed. The results of the analysis presented here show that the faunal material of the Stampede site is extensively burnt, which seems to be more in line with the intentional disposal of bones in hearth features, possibly for cleaning purposes, than with bone grease manufacture. The methodological issues regarding the identification of bone grease rendering from archaeozoological assemblages are discussed here. Author Keywords: Bone Grease Rendering, Carcass Processing Behaviour, Faunal Analysis, Great Plains, Northern Plains, Subsistence

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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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1973 - 2033
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