Graduate Theses & Dissertations

Pages

Automated Separation and Preconcentration of Ultra-Trace Levels of Radionuclides in Complex Matrices by Online Ion Exchange Chromatography Coupled with Inductively Coupled Plasma Mass Spectrometry (ICP-MS)
Radionuclides occur in the environment both naturally and artificially. Along with weapons testing and nuclear reactor operations, activities such as mining, fuel fabrication and fuel reprocessing are also major contributors to nuclear waste in the environment. In terms of nuclear safety, the concentration of radionuclides in nuclear waste must be monitored and reported before storage and/or discharge. Similarly, radionuclide waste from mining activities also contains radionuclides that need to be monitored. In addition, a knowledge of ongoing radionuclide concentrations is often required under certain ‘special’ conditions, for example in the area surrounding nuclear and mining operations, or when nuclear and other accidents occur. Thus, there is a huge demand for new methods that are suitable for continuously monitoring and rapidly analyzing radionuclide levels, especially in emergency situations. In this study, new automated analytical methods were successfully developed to measure ultra trace levels of single or multiple radionuclides in various environmental samples with the goal of faster analysis times and less analyst involvement while achieving detection limits suitable for typical environmental concentrations. Author Keywords: automation, ICP-MS, ion exchange, radionuclide
Ontario's Aboriginal Education Strategy
Since 2007, Aboriginal education initiatives in Ontario have been supported by the Aboriginal Education Strategy (Strategy) under provincial Liberal governments. Using a comparative analysis, this thesis seeks to identify how the Strategy supports and/or does not support components of critical pedagogy to promote transformational learning for all students in Ontario's publicly funded schools. A brief historical timeline of Aboriginal education in Canada and the current situation of educational attainment for Aboriginal and non-Aboriginal peoples provides context for the thesis. Through an examination of policy documents and resources related to the Strategy, I identify both strengths and areas for improvement in the Strategy to meet expectations of critical pedagogy. Finally, I suggest recommendations to improve the Strategy in order to achieve its potential for the benefit of all students in Ontario's public schools. Author Keywords: Aboriginal students, Critical pedagogy, Education, Ontario, Policy
Archaeology and Reconciliation in the Williams Treaties Territory
This thesis examines the history of Indigenous inclusion in the discipline of archaeology and how archaeologists can provide reconciliation when working with Indigenous peoples in their territory. This thesis focuses on the territory of the Williams Treaties with a particular focus on the location of Nogojiwanong (Peterborough). My data consists of in-depth interviews from ten informants and studying three case studies that happened in the area. I take my informants’ suggestions and apply them to my case studies, to show practical examples of how we can provide reconciliation in the field of archaeology. Author Keywords: Decolonization , Heritage Management , Indigenous, Reconciliation
Equilibria and distribution models of ionizing organic chemical contaminants in environmental systems
Ionizing organic chemicals are recognized as constituting a large fraction of the organic chemicals of commerce. Many governments internationally are engaged in the time-consuming and expensive task of chemical risk assessment for the protection of human and environmental health. There are standard models that are consistently used to supplement experimental and monitoring data in such assessments of non-ionizing organics by both government regulators and industry stakeholders. No such standard models exist for ionizing organics. Equilibrium distribution models, the foundational equations within multimedia environmental fate models for non-ionizing organics, were developed for the standard series of biphasic systems: air-water, particle-water, air-particle and organic-aqueous phases within living tissue. Multiple chemical species due to the ionization reaction were considered for each system. It was confirmed that, under select conditions, the properties of the neutral parent are sufficient to predict the overall distribution of the organic chemical. Complications due to biotransformation and paucity of identifiable equilibrium distribution data for ionizing organics limited the development of the model for living tissues. However, the equilibrium distributions of ionizing organics within this biotic system were shown to correlate with the abiotic sediment-water system. This suggests that the model developed for particle-water systems should be adaptable to the biotic system as model input and test data become available. Observational data for soil- and sediment- water systems, i.e., particle-water systems, allowed the development of a primarily non-empirical distribution equation for mono-protic acids; this model was almost entirely theoretically derived. The theoretical approach to model development allowed a quantitative assessment of the role of the neutral ion pair, resulting from the complexation of the organic anion with metal cations. To demonstrate the model's potential usefulness in governmental screening risk assessments, it was applied to a broad range of mono-protic organics including drugs and pesticides using standard property estimation software and generic inputs. The order-of-magnitude agreement between prediction and observation typical of the existing models of non-ionizing organics was generally achieved for the chemicals tested. The model was sensitive to the octanol-water partition coefficient of the most populous species. No calibration set was used in the development of any of the models presented. Author Keywords: bioconcentration, chemical equilibrium, environmental modelling, ionizing organic, sorption
New Interpretations from Old Data
Range contractions and expansions are important ecological concepts for species management decisions. These decisions relate not only to rare and endangered species but to common and invasive species as well. The development of the broad spatiotemporal extent models that are helpful in examining range fluctuations can be challenging given the lack of data expansive enough to cover the time periods and geographic extents needed to fit the models. Archival records such as museum databases and harvest data can provide the spatiotemporal extent needed but present statistical challenges given they represent presence-only location information. In this thesis, I used maximum entropy and Bayesian hierarchical occupancy algorithms fitted with archival presence-only records to develop spatiotemporal models covering broad spatial and temporal extents for snowshoe hare and Canada lynx. These two algorithm types are well suited for presence-only data records and can be adapted to include biological and physical processes, thus improving the ecological realism of the models. Using these modelling methods, I found the extent of occurrence (EOO) and area of occupancy (AOO) varied greatly over time and space for both snowshoe hare and Canada lynx, suggesting that management decisions for these species should include consideration of these variations. While the presence-only data were appropriate for model development and understanding changing values in EOO and AOO, it sometimes lacked the locational accuracy and precision needed to create fine scale ecological analyses, thus resulting in somewhat coarse but potentially relevant conclusions. Author Keywords: Area of occupancy, Bayesian hierarchical models, Canada lynx, Extent of occurrence, Presence-only data, Snowshoe hare
Anthropogenic particles and microplastics in headwater lake catchments in Muskoka-Haliburton, Canada
Microplastics, plastic particles less than 5 mm in diameter, are ubiquitous in the environment. This study estimated the abundance of microplastics (MP) in atmospheric deposition from four background monitoring stations in Muskoka-Haliburton, south-central Ontario, Canada and quantified the fate of microplastics to three background headwater lake catchments in Muskoka-Haliburton. Microplastics were observed across all sample media with polyethylene terephthalate and polyamide being predominant. The average atmospheric deposition of anthropogenic particles was 57 particles/m2/day with a plastic deposition rate of 7 MP/m2/day. Atmospheric deposition represented the highest daily microplastic flux rate to the three headwater lake catchments compared, 1.5 to 4 times greater than the flux rate for the inflow streams suggesting that atmospheric deposition can account for all the inflowing microplastics. A large fraction of the microplastics from atmospheric deposition (41 – 73%) were retained in the terrestrial catchment and there was a high retention of microplastics in each of the study lakes (1.44 – 7.39 million MP/day; 30 – 45%) suggesting that a large fraction of the terrestrial catchment export is retained by the lakes and that lakes are a reservoir for microplastics. Author Keywords: Atmospheric deposition, Microplastics, Ontario, Plastic pollution, Sinks, Sources
Historic Magnetogram Digitization
The conversion of historical analog images to time series data was performed by using deconvolution for pre-processing, followed by the use of custom built digitization algorithms. These algorithms have been developed to be user friendly with the objective of aiding in the creation of a data set from decades of mechanical observations collected from the Agincourt and Toronto geomagnetic observatories beginning in the 1840s. The created algorithms follow a structure which begins with pre-processing followed by tracing and pattern detection. Each digitized magnetogram was then visually inspected, and the algorithm performance verified to ensure accuracy, and to allow the data to later be connected to create a long-running time-series. Author Keywords: Magnetograms
Agriculture as Niche Construction
The Neolithic Period (c. 6200 – 4900 BC) in the Struma River Valley led to numerous episodes of cultural diversification. When compared with the neighbouring regions, the ecological characteristics of the Struma River Valley are particularly heterogeneous and the Neolithic populations must have adapted to this distinctive and localized ecological setting. It then becomes reasonable to ask if the evolution of cultural variability in the Struma River Valley was at least partially driven by the ecological setting and differentiation in the evolution of the early agricultural niche. In this thesis, I apply an approach based on niche construction theory and Maxent species distribution modeling in order to characterize the relationship between culture and ecology during each stage of the Neolithic Period and to assess diachronic change. An interpretation of the results demonstrates that the continuous reconstruction of the early agricultural niche allowed for settlement expansion into new eco-cultural niches presenting different natural selection pressures and that cultural change followed. I also found that cultural and historical contingencies played an equally important role on the evolution of populations and that ecological factors alone cannot account for the numerous episodes of cultural diversification that occurred throughout the region. Author Keywords: Agriculture, Bulgaria, Eco-cultural Niche Modeling, Greece, Neolithic, Niche Construction
Social Anxiety, Theory of Mind, and Executive Function in Late Adolescence and Early Adulthood
Studies that have investigated the relation between social anxiety and theory of mind or executive function have shown that individuals with deficits in these cognitive processes have high levels of social anxiety. However, methodological problems make past findings questionable and difficult to interpret. The current study investigated whether deficits in theory of mind and executive function predicted symptoms of social anxiety in 99 older adolescents and young adults (18-29). On average, participants had moderate levels of social anxiety. Performance on measures of theory of mind and executive function did not predict symptoms of social anxiety. This lack of associations could be due to characteristics of the current sample, methodological differences in the current study compared to past studies, or the type of social anxiety and theory of mind measure used. Implications and directions for future research are discussed. Author Keywords: Early Adulthood, Executive Function, Late Adolescence, Social Anxiety, Theory of Mind
Influence of nitrogen deposition on the vegetation community of Irish oak woodlands
In this study, the influence of N deposition on the vegetation community of semi-natural oak woodlands in Ireland was assessed through national and regional scale analysis of forest plot data. At both scales, Canonical Correspondence Analysis suggested that N deposition was a predictor of community composition, although site-specific soil characteristics were the strongest predictors of the species dataset. Threshold Indicator Taxon Analysis suggested that the vegetation community demonstrated the most change at 13.2 kg N ha-1 yr-1. While this change point falls within the current recommended critical load range for nutrient nitrogen for acidophilous oak dominated woodlands (10 to 15 kg N ha-1 yr-1), it is notable that 23% of species recorded had individual change points below this range, and could potentially be lost from this habitat if deposition increases. The results from this study suggest that, for acidophilous oak woodlands, habitat conservation policies should be unified with N emission reduction policies. Author Keywords: community composition, critical load, nitrogen depositioin, oak woodland, species richness, Taxon Indicator Threshold Analysis
Effect of Listing a Stock on the S&P 500 Index on the Stock’s Volatility
This paper investigates the effect of listing a stock on the S&P 500 Index on the stock’s volatility, using various econometrics models: GARCH and EGARCH. The study mainly addresses three issues; firstly, it analyzes stock volatility in two sub-periods, secondly, it determines whether the announcement can account for the fluctuations in the price of the stock, and finally, it investigates the change in the stock’s variance. After isolating the effects of external and industry shock by using the returns on the S&P 500 Index as a proxy, the author finds evidence of structural change in the volatility of stocks after that stock is added to the index. Additionally, the existence of a dominant symmetric effect, which captures the response of volatility to news, indicate that following the onset of including the stock on the index, information flowing into the market increased. However, the rate at which old news is captured in price falls. The empirical evidence also suggests that on average a stocks variance falls and that the announcement to list a stock on the index has little effect on the stock’s price. Author Keywords: EGARCH, GARCH, S&P 500 Index, Symmetric Effect, Volatility
Relationship between Virginity Scripts and Precoital Sexual Behaviour
Past research has examined the influence of cultural scripts on our first coital experience, but the impact of virginity scripts on precoital sexual behaviour remains unknown. The purpose of this study sought to examine the link between Carpenter’s (2001) cognitive frameworks of virginity and precoital sexual behaviour. Two hundred and forty eight participants (32 men, 215 women, and one unknown) were recruited from a Canadian university, all of whom had experienced precoital behaviour and first sexual intercourse. The findings indicated that past precoital behaviour and coital behaviour with first sexual partner had different relationship patterns with respect to virginity scripts. Virginity scripts were also related to current sexual sensation seeking, motivation for erotic arousal, sexual compatibility, comfort with sexuality, and approach to sexual relationships. Author Keywords: precoital sexual behaviour, sexual scripts, virginity frameworks, virginity loss

Pages

Description

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

In collections

Search Our Digital Collections

Query

Enabled Filters

  • (-) ≠ Biology

Filter Results

Date

1973 - 2033
(decades)
Specify date range: Show
Format: 2023/10/01

Collection

Author Name

Show more

Name (Any)

Show more

Degree

Degree Discipline

Show more

Subject (Topic)

Show more