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Wilfrid Laurier University

Theses/Dissertations

2020

Articles 1 - 12 of 12

Full-Text Articles in Physical Sciences and Mathematics

Characterizing The Hydrological Function Of Treed Bogs In The Zone Of Discontinuous Permafrost, Brenden Disher Jan 2020

Characterizing The Hydrological Function Of Treed Bogs In The Zone Of Discontinuous Permafrost, Brenden Disher

Theses and Dissertations (Comprehensive)

The loss of permafrost has produced a wholesale conversion from forest to wetland, and many studies have analyzed the effects of permafrost thaw-induced land cover change on the hydrology and ecology of landscapes within the Taiga Plains. The permafrost thaw driven areal shrinkage of forested plateaux and their replacement by treeless wetlands is well documented, and the co-occurrence of permafrost and black spruce forest cover is the basis for areal estimates of the former. However, field studies conducted at a peatland dominated landscape near Fort Simpson, NWT indicate that tree canopy may persist following the loss of permafrost and the …

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Impact Of Seismic Lines On The Hydrology Of Wetlands In The Discontinuous Permafrost Zone, Southwestern Northwest Territories, Angela Hamilton Jan 2020

Impact Of Seismic Lines On The Hydrology Of Wetlands In The Discontinuous Permafrost Zone, Southwestern Northwest Territories, Angela Hamilton

Theses and Dissertations (Comprehensive)

Previous studies in the southern Northwest Territories have shown the underlying discontinuous permafrost is sensitive to disturbances such as the creation of seismic lines. Their creation has resulted in compaction topsoil and tree removal causing accelerated permafrost thaw. The loss of permafrost has caused seismic lines’ surface elevation to subside, which allows water to conjugate. This increases the soil moisture of a seismic line, which results in preferential thaw along the seismic line edges. Thaw along the edges over time has connected more previously isolated wetlands to seismic lines. This leads to more water entering, resulting in higher water levels …

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Assessing Threats And Mitigation For Scarlet Ammannia (Ammannia Robusta) In Southwestern Ontario, Kayla Salive Jan 2020

Assessing Threats And Mitigation For Scarlet Ammannia (Ammannia Robusta) In Southwestern Ontario, Kayla Salive

Theses and Dissertations (Comprehensive)

Scarlet Ammannia (Ammannia robusta) is an annual emergent wetland plant of the Lythraceae family. Throughout most of its distribution, the species population is stable under present conditions. However, this is not the case in Canada, where A. robusta is considered endangered with only a few small populations documented in British Columbia and Ontario. In response, a recovery strategy was created for A. robusta outlining the lack of information on the species biology and ecology, with a primary objective to assess the populations in Ontario and gain information on what may be contributing to the species rarity. To assess …

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Reconstructing Hydrologic Conditions And Metals Supplied By The Peace River To The Peace-Athabasca Delta, Jelle André Faber Jan 2020

Reconstructing Hydrologic Conditions And Metals Supplied By The Peace River To The Peace-Athabasca Delta, Jelle André Faber

Theses and Dissertations (Comprehensive)

The Peace-Athabasca Delta (PAD) in northern Alberta, Canada, is recognized internationally for its ecological, historical, and cultural significance. The delta is mostly within Wood Buffalo National Park, a UNESCO World Heritage Site, and is a Ramsar Wetland of International Importance. The construction of the WAC Bennett Dam (1967) and the Site C Dam (ongoing, 2024) on the Peace River, and expansion of the Alberta Oil Sands industry along the Athabasca River have raised concerns over water quantity and quality in the delta. When industry operations began, effective monitoring had not been implemented. Consequently, pre-industrial reference conditions are unknown and can …

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Asset Pricing Under Randomized Solvable Diffusions, Hiromichi Kato Jan 2020

Asset Pricing Under Randomized Solvable Diffusions, Hiromichi Kato

Theses and Dissertations (Comprehensive)

By employing a randomization procedure on the geometric Brownian motion (GBM) model, we construct our new pricing models with stochastic volatility exhibiting symmetric smiles in the log-forward moneyness, and admitting simple closed-form analytical expressions for European-style option prices. We assume that there are no infinitesimal correlations between the underlying asset prices and their volatility, and the integrated squared volatility processes are random variables with well-known probability density functions. Under some regularity conditions, closed-form expressions are obtained by taking the expectation of option prices under diffusion models over the integrated squared volatility process, which relate to the Bayesian framework in the …

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Determination Of Samarium And Dysprosium Solubility, Seana Brennan Jan 2020

Determination Of Samarium And Dysprosium Solubility, Seana Brennan

Theses and Dissertations (Comprehensive)

In recent years, the use of Rare Earth Elements (REE) has rapidly increased, resulting in numerous potential anthropogenic inputs to the environment. As a result, these metals are emerging as microcontaminants and pose a potential threat to aquatic life. However, the toxicity of REE are largely unknown due, in part, to the limited information on their chemical speciation. The purpose of this project was to gain an understanding of REE precipitate formation and solubility as the foundation for the development of the chemical equilibrium component of toxicity prediction models. Solubility experiments were conducted with Samarium, (Sm), a light REE, and …

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An Evaluation Of Ground-Freezing Methods In The Zone Of Discontinuous Permafrost, Northwest Territories, Elzbieta Mastej Ms Jan 2020

An Evaluation Of Ground-Freezing Methods In The Zone Of Discontinuous Permafrost, Northwest Territories, Elzbieta Mastej Ms

Theses and Dissertations (Comprehensive)

Northwestern Canada is one of the most rapidly warming regions on Earth. The southern limit of the discontinuous permafrost zone is highly sensitive to small climatic fluctuations and presently experiencing a rapid landscape change due to accelerated permafrost thaw, which is further exacerbated by anthropogenic disturbances such as seismic exploration. Recent research has begun to examine both natural and mechanical approaches to minimize permafrost loss, although the utility of such methods in peatland environments is not well understood. This study explored the efficiency of natural and artificial ground cooling processes in a peatland environment by evaluating snow exclusion and thermosyphon …

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Monitoring Environmental Change Using A Participatory Modified Photovoice Approach With Indigenous Knowledge Holders In Kakisa, Northwest Territories, Kaitlin Kok Jan 2020

Monitoring Environmental Change Using A Participatory Modified Photovoice Approach With Indigenous Knowledge Holders In Kakisa, Northwest Territories, Kaitlin Kok

Theses and Dissertations (Comprehensive)

In response to growing pressures from climate change and the lack of a monitoring strategy for food security at a local and regional level in the Northwest Territories, there is an urgency for residents to record their own images of change in relation to harvester safety. This thesis explores the connection between geographic information systems, sustainable food systems, indigenous knowledge and the importance of place. The objective of this study is two-fold: (a) to develop a monitoring system in conjunction with the community of Kakisa and (b) to increase the resilience of the local food system. The methods used derive …

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Aggregate Loss Model With Poisson-Tweedie Loss Frequency, Si Chen Jan 2020

Aggregate Loss Model With Poisson-Tweedie Loss Frequency, Si Chen

Theses and Dissertations (Comprehensive)

The aggregate loss model has applications in various areas such as financial risk management and actuarial science. The aggregate loss is the summation of all random losses occurred in a period, and it is governed by both the loss severity and the loss frequency. While the impact of the loss severity on aggregate loss is well studied, less focus is paid on the influence of loss frequency on aggregate loss, which motivates our study. In this thesis, we enrich the aggregate loss framework by introducing the Poisson-Tweedie distribution as a candidate for modelling loss frequency, prove the closedness of Poisson-Tweedie …

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Plasmonic Slab Waveguides: Theory & Application For Sensors, Anum Khattak Jan 2020

Plasmonic Slab Waveguides: Theory & Application For Sensors, Anum Khattak

Theses and Dissertations (Comprehensive)

Through surface plasmon polaritons (SPPs) that propagate along the interface between a metal and a dielectric material, plasmonic waveguides have the ability to confine light at subwavelength scale beyond the diffraction limit, which opens a promising platform to further downsize the active and passive photonic devices. The fields of the SPPs have maximum amplitude at the metal/dielectric interface and decay exponentially toward both media, where the penetration of the fields in the dielectric is very susceptible to the change in the refractive index of the dielectric. This makes surface plasmon resonance (SPR) a remarkable technique in sensor applications to investigate …

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Health-Aware Food Planner: A Personalized Recipe Generation Approach Based On Gpt-2, Bushra Aljbawi Jan 2020

Health-Aware Food Planner: A Personalized Recipe Generation Approach Based On Gpt-2, Bushra Aljbawi

Theses and Dissertations (Comprehensive)

"What to eat today?" With the flourish of Internet, more and more people nowadays are inclined to find an answer to this most problematic question online. The recent explosion of food networks; however, produces large volumes of recipes, making it even harder to make an informed decision. This yields the need for advanced decision-making algorithms and efficient recommendation systems. Conventional recommender systems are not feasible anymore as food is a complicated feature that presents unique challenges and is less studied. For example, it can be one of the main reasons for obesity and many other chronic diseases. Food recommender system …

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Investigating Diel, Seasonal, And Interannual Variability Of Dissolved And Particulate Stable Carbon Isotope Values In A Eutrophic Boreal Lake, Rachel Henderson Jan 2020

Investigating Diel, Seasonal, And Interannual Variability Of Dissolved And Particulate Stable Carbon Isotope Values In A Eutrophic Boreal Lake, Rachel Henderson

Theses and Dissertations (Comprehensive)

Lakes are globally significant sources, sinks, and conduits of carbon. Cultural eutrophication of freshwater promotes the growth of phytoplankton blooms, which can transform, respire, and sequester large amounts of carbon. Analysis of stable carbon isotopes is a common tool to study the movement of carbon through the aquatic carbon cycle. The causes of temporal variability in δ13C values at different timescales are not well understood, and differ between lakes. In this study, I investigated diel, seasonal, and interannual variability in δ13C values of dissolved inorganic carbon (DIC) and particulate organic carbon (POC) in Lake 227, an …

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