Graduate Theses & Dissertations


Influence of Nitrogen Deposition on Community Composition in Pinus banksiana Forests Across Northwestern Canada
Anthropogenic atmospheric emissions and subsequent deposition of nitrogen (N) can affect N-sensitive habitats and lead to shifts in plant species community composition. This study assessed the effects of N deposition on plant community composition for Jack pine forests across northwestern Canada and across a smaller subset of sites surrounding the Athabasca Oil Sands Region (AOSR) using ‘gradient forest’ analysis. Predictor influence on community composition varied depending on the scale of the study and relatively distinct thresholds were identified for different plant groups. In the larger scale study, a total deposited nitrogen (TDN) threshold of 1.5 – 3 kg N ha-1yr-1 was well suited to protect predominantly lichen species, consistent with lichen-based critical loads from other studies. Across the smaller scale study, a TDN threshold of 5.6 kg N ha-1yr-1 was primarily associated with vascular species changepoints but did include some important N-indicator lichen and bryophyte species. Author Keywords: critical loads, gradientForest, Jack pine, Nitrogen deposition, species composition
Interpretation of forest harvest recovery using field-based and spectral metrics in a Landsat time series in Northwestern Ontario
The forestry sector has a well-developed history of using remote sensing to identify structural characteristics of forests and to detect and attribute changes that occur in forested landscapes. Monitoring the recovery of disturbed forests is an important factor in long term forest management. However, forest that is recovered spectrally may not be recovered when considered in terms of a Free to Grow assessment. A Free to Grow assessment is used in Ontario to determine whether a disturbed site will likely achieve a desired future state, i.e., is recovered according to a forestry perspective. The objective of this research was to determine the relationship between a pixel-based Landsat Time Series of spectral recovery and the results of Free to Grow assessments. Spectral trajectories were generated from representative pixels within known harvested forest areas. Results indicate that while Free to Grow sites often achieve spectral recovery (>90%), many non-Free to Grow sites were classified as spectrally recovered, suggesting that improved methods of spectral recovery monitoring are needed. Author Keywords: forest recovery, Free to Grow, Landsat Time Series, LandTrendr, Pixel-based, spectral recovery
Proximal Soil Nutrient Sensing in Croplands through Multispectral Imaging from Unmanned Aerial Vehicles (UAV) for Precision Agriculture Applications
Currently, UAVs are deployed to measure crop health in a timely manner by mapping vegetation indices. A study using two different fields was conducted in order to search for a relationship that may exist between crop health and soil fertility. A UAV equipped with sensor technology was used for mapping of vegetation indices which were then statistically compared to soil nutrient data collected via soil sampling. Elevation data was also collected which was then statistically compared to soil nutrients as well as crop health. Results of this study were unfortunately impacted by variables outside of the researcher’s control. Moisture became the greatest limiting factor in 2016 followed by an excess of rain in 2017. Results did not show any promising correlations as moisture uncontrollably became the defining variable. Further research in a more controlled setting will need to be conducted in order to explore this potential relationship. Author Keywords: Agriculture, Multispectral Imagery, Precision Agriculture, Proximal Soil Sensing, Remote Sensing, Unmanned Aerial Vehicle
Emotional Competencies in Mothers and Children and their Relationship with Health Care Utilization, Somatization and Health Anxiety.
Young children learn their emotion regulation skills by modeling and internalizing their caregivers' emotional competencies. Inadequate or problematic emotional competencies in parents can result in insufficient development of these competencies in children, which can have severe consequences on multiple domains of their lives, including physical wellbeing. This study examined the relationship between emotional competencies, health care usage rates, somatization and health anxiety in the context of a family with young children. Participants were mothers of children 4-11 years old recruited in the community. The results revealed a relationship between mother’s emotional competencies and mother and child’s health care usage rates. Mother’s health care usage rates were also linked to mother’s health anxiety and child’s somatic symptoms. These findings add to our understanding of the relationship between emotional competencies of parents and children, and the effects it can have on both mother’s and child’s physical wellbeing. Implications and avenues for future research are discussed. Author Keywords: emotional competencies, health care usage, mother and child, somatization
As wild turkeys (Meleagris gallopavo silvestris) move farther north, informed management decisions are critical to support the sustainability of this reintroduced species. We tracked roost tree selection and patterns of the network of roost trees, for wild turkeys, over 2 years in Peterborough, ON, using GPS and VHF transmitters. Wild turkeys showed preference for taller and larger roost trees, with winter roosts closer to buildings. The roost network exhibited a scale-free network, meaning certain roosts served as hubs, while other roosts were less frequently used. The fine scale results suggest that roost trees are selected for predator avoidance, and that selection changes with the season, probably because of its influence on foraging ability. At a larger scale, winter roosts were chosen for their proximity to supplemental food sources. These findings demonstrate the dependence of wild turkeys on humans and the supplemental sources we unintentionally provide. Author Keywords:
First Time…A Second Time
The purpose of the current study was to explore virginity loss experiences in lesbian, gay, and bisexual individuals (LGB), specifically those who have had both a sexual experience with a member of a different sex and a member of the same sex. This phenomenon is what the current study is defining as second virginity loss. Participants consisted of 645 LGB self-identified individuals, the sample was approximately half women (53%) and ages ranged from 18-65. Further, six semi-structured interviews were conducted to gain a clearer understanding of LGB individuals virginity loss experiences. Of the sample, approximately 60% of each sexual orientation reported having two sexual experiences they equated with virginity loss, one with a member of a different sex, and one with a member of the same sex. Analyses of both the qualitative and quantitative data were conducted in an attempt to gain an understanding in three main areas: (1) definitions of virginity loss, (2) virginity beliefs, and (3) motivations. It was found that LGB individuals continue to hold heteronormative definitions of virginity loss, i.e. penile-vaginal intercourse, though these definitions were found to be transitional in nature. LGB individuals also seem to hold more gift related beliefs toward their same-sex experience and more stigma related beliefs toward their different sex experience, however, as shown by previous research (Carpenter, 2001, 2002), most LGB individuals highly endorsed process beliefs. Finally, motivations for virginity loss were found to be consistent with two main themes: validation and drive. Overall, this research suggests that the LGB community has a fairly complicated relationship with virginity but certainly do not feel exempt from the concept or the pressures attached. The current study is the first to explore the phenomenon of second virginity loss in LGB individuals and should be used as a foundation for future research in both first sexual experience and LGB fields to build upon. Author Keywords: first sexual experience, LGB, mixed-methods, second virginity loss, virginity
Automated Grading of UML Class Diagrams
Learning how to model the structural properties of a problem domain or an object-oriented design in form of a class diagram is an essential learning task in many software engineering courses. Since grading UML assignments is a cumbersome and time-consuming task, there is a need for an automated grading approach that can assist the instructors by speeding up the grading process, as well as ensuring consistency and fairness for large classrooms. This thesis presents an approach for automated grading of UML class diagrams. A metamodel is proposed to establish mappings between the instructor solution and all the solutions for a class, which allows the instructor to easily adjust the grading scheme. The approach uses a grading algorithm that uses syntactic, semantic and structural matching to match a student's solutions with the instructor's solution. The efficiency of this automated grading approach has been empirically evaluated when applied in two real world settings: a beginner undergraduate class of 103 students required to create a object-oriented design model, and an advanced undergraduate class of 89 students elaborating a domain model. The experiment result shows that the grading approach should be configurable so that the grading approach can adapt the grading strategy and strictness to the level of the students and the grading styles of the different instructors. Also it is important to considering multiple solution variants in the grading process. The grading algorithm and tool are proposed and validated experimentally. Author Keywords: automated grading, class diagrams, model comparison
Thinking High When Feeling Shy
Social anxiety often co-occurs with substance use disorders – various psychological variables, contextual factors, and implicit cognitions may help explain their relationship. This thesis examined whether social anxiety and psychological variables (jointly and independently) helped predict substance use and related problems. It also explored whether social anxiety group membership helped predict implicit cannabis-sedation associations and substance use desirability. A sample of undergraduate student volunteers (N = 65) completed a computer task, questionnaires with anxiety-provoking vignettes, and online questionnaires. Results indicate that fear of negative evaluation and anxiety sensitivity are important predictors of alcohol and cannabis (respectively) use and problems. Social anxiety group was related to increased cannabis desirability in performance contexts. No significant implicit cannabis-sedation associations were identified. Our findings highlight the importance of certain variables in social anxiety and substance use relationships, and considering contextual factors when assessing substance desirability. It also provides preliminary evidence of a novel implicit cannabis-sedation measure. Author Keywords: Coping, Emotion, Implicit Cognition, Social Anxiety, Substance Use
Understanding Angler Dynamics in a Recreational Lake Trout (Salvelinus namaycush) Fishery in Algonquin Provincial Park Using Long-Term Access Creel Data
In order to effectively manage recreational fisheries, it is important to understand how the resource is being used. In this thesis, long-term creel census data, collected on Lake Opeongo in Algonquin Provincial Park, Ontario, Canada was used to assess fine-scale angler dynamics within a recreational Lake Trout (Salvelinus namaycush) fishery. The spatial distribution of angler reported catch locations of Lake Trout within the lake, was assessed using an Optimized Hotspot Analysis in ArcGIS. Areas of significant clustering of catch locations were revealed during all time periods and varied in size and location both seasonally and temporally. Cormack-Jolly-Seber models were used to evaluate the probability of individual angling boats persisting in the regional fishery and being detected on Lake Opeongo through time, as well as to examine the effect of angler travel distance and gas prices on participation parameters. Time-varying models revealed that the probability of an angler persisting in the fishery varied, while detection estimates remained stable. Travel distance had a negative effect on both parameters while increased gas prices only had a slight negative effect on detection estimates. Additionally, among Lake Opeongo anglers, angling avidity varied as did lake specific fishing experience. Average CUE was found to be higher among angling parties who visited the lake more often than fishing parties who visited relatively few times. Author Keywords:
An Exploration of Attachment Influences on Rape Attitudes
While there is substantial research on the influence of adverse childhood experiences on sexual offending behaviours and attachment representations on sexual offending behaviours, few studies to date have explored how adverse childhood experiences and attachment representations act together to influence the development of rape attitudes in a non-clinical population. The purpose of this thesis was to explore how childhood experiences and attachment may help to understand the development of rape attitudes. Data were collected from 273 undergraduate students who completed self-report questionnaires pertaining to their attachment, childhood experiences and rape attitudes. Correlational and Structural Equation analyses were computed, and the results did not find support for the simultaneous influence of adverse childhood experiences and attachment representations on rape attitudes. Given that the sample was primarily female (83%), the results indicate that the outcomes of adverse childhood experiences on sexual attitudes may differ by gender. Understanding the formation of rape attitudes is important to understand the motivations behind sexual assault behaviours. Author Keywords: adverse childhood experiences, rape attitudes
Temporal Variability of Coloured Dissolved Organic Matter in the Canada Basin, Arctic Ocean (2007-2017)
This thesis investigated coloured and fluorescent dissolved organic matter in the Canada Basin, Arctic Ocean from 2007 to 2017. The first interannual time-series of its kind in the Canada Basin incorporated the use of EEM-PARAFAC to validate a seven-component model. Statistical temporal tests revealed (1) an increasing protein-like intensity in the upper polar mixed layer (UPML); (2) increasing intensities of humic-like components in the halocline due to increasing freshwater content; and (3) no change in DOM composition in deeper Atlantic waters (AW) congruent with the long residence time of the water mass (> 30 years). The significant decline in sea ice concentration was related to a decrease in humic-like FDOM due to enhanced photodegradation and an increase in protein-like FDOM, likely the results of increased biological activities in surface layers. This research provides evidence that the changes in physical and biological environment in the Arctic regions have already profound impacts on the composition and distribution of FDOM. Author Keywords: absorbance, Arctic Ocean, dissolved organic matter, fluorescence, parallel factor analysis, time-series
Developing social skills
Guidelines regarding social skills interventions for children with ASD suggest incorporating a holistic approach. This includes increasing the family’s understanding of deficits associated with ASD, integrations of natural environments, and parents as active agents while supporting their well-being. The current availability of holistic parent-mediated interventions for children with ASD is limited, with no qualitative understanding of its potential benefits for either the parent or child. The current study examined qualitative parent reports on a parent-mediated social skills intervention for children with ASD (TalkAbilityTM) incorporating a longitudinal approach (i.e., 6-month follow-up). Following Braun and Clarke’s model of thematic analysis, data was coded into four themes: 1) communication difficulties, frustrations and progress, 2) social relationships and concerns, 3) communication strategies, and 4) thoughts and emotions surrounding TalkAbilityTM. Results highlight the importance of considering parent experiences regarding interventions for their child’s social communication skills through a qualitative viewpoint. Author Keywords: autism spectrum disorder, parent-mediated intervention, qualitative review


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