Graduate Theses & Dissertations


Social Anxiety and Emotional Competence
Prior research has examined social anxiety, emotional competence (EC) and life adjustment (i.e., loneliness and life satisfaction) using cross-sectional designs, although there is limited information on their association over time. The present study examined the impact of social anxiety on life adjustment and assessed if EC could mediate this relationship from young to middle adulthood. University students (N = 283) completed self-report measures at two time points: in first year university and 15 years later. The results accord with previous research demonstrating the stability and slight decrease of social anxiety over time. Social anxiety in young adulthood was a robust predictor of loneliness in middle adulthood, and a weak predictor of life dissatisfaction for men. Mediation analyses revealed that social anxiety was indirectly associated with interpersonal adjustment via EC, especially the intrapersonal EC domain. Social anxiety requires early intervention and EC may help to prevent later social anxiety and maladjustment. Author Keywords: emotional intelligence, life adjustment, social anxiety
It's All in Your Head
The Continuity Hypothesis states that dreams reflect waking day cognition and experiences, which reflect one’s mental health status. As such, dreams are, by extension, cognitions that occur during sleep. To date, Cognitive Behavioural Therapy (CBT) is deemed the most efficacious method of social anxiety treatment by working with cognitions. The current study utilized both CBT and The Storytelling Method (TSM) of dream interpretation, whose methodology is based on CBT; CBT works with waking cognitions and TSM works with sleep cognition. This study examined the effectiveness in decreasing social anxiety symptoms with TSM and comparing its efficacy to a traditional CBT technique. Undergraduate psychology students (N = 36) completed a daily journal of either the TSM or CBT format for two weeks. Participants completed self-report measures of social anxiety, state-anxiety, and depression before and after practicing either method. TSM did not significantly decrease levels of social anxiety, state-anxiety, or depression, whereas CBT significantly decreased only social anxiety levels. Dream content reflecting waking day anxiety and depression did not decrease over time, coinciding with the findings that students did not experience a decrease in their waking day life, supporting the Continuity Hypothesis. Findings suggest anxiety and depression to be very stable in this sample. Future research should explore interventions that are clinician-guided, in a group setting, or, occur over a longer period of time. Author Keywords: Content Analysis, Social anxiety, The Storytelling Method
Study of Aerosols for use in Water Remediation of Pharmaceutical Pollutants
In this thesis, aerosolization was studied as a possible means of water remediation for several environmentally relevant pharmaceutical pollutants, known for their persistence in wastewater effluent and potable water sources. Seven different pharmaceutical compounds and a well-known plasticizer were all shown to decrease considerably in concentration in aerosol that was produced and subsequently collected within a short time span. Strong evidence is presented that an enhanced rate of partitioning into the gas phase at the air-water interface of water droplets exists for every compound tested relative to that occurring in bulk solution. UV photolysis in aerosols was also explored and shown for sulfamethoxazole to be at least an order of magnitude faster in aerosols then in bulk solution. The implications towards both the environmental fate, and removal of these compounds from water sources is discussed. Author Keywords: Aerosols, Air-water partitioning, Pharmaceuticals, Photolysis, Sulfamethoxazole
Anthropogenic microfibres in background natural environments in Ireland
Microfibres, which are threadlike particles < 5 mm, are the most common type of microplastic reported in the environment. However, few studies have focused on their abundance in background natural environments. This study assessed the abundance of microfibres in rainfall samples (from four precipitation monitoring stations) and across three headwater lake catchments that were in remote, undeveloped areas, away from anthropogenic disturbance and anthropogenic emission sources (i.e., sites were background natural environments). Anthropogenic microfibres were observed in all samples using visual identification methods, with Raman spectroscopy confirming the presence of polyester film and synthetic pigments, e.g., indigo and hostasol green. The estimated annual average atmospheric deposition of microfibres was ~28,800 mf m-2. Meteorological variables, e.g., rain, wind direction, and relative humidity were correlated with the abundance of microfibres. The average abundance of microfibres in headwater lake catchments was 24 mf g-1 in moss, 0.70 mf m-3 in surface trawl, 9,690 mf m-3 in subsurface, 910 mf kg-1 in lake sediment and 576 mf kg-1 in lakeshore sediment. Author Keywords: Atmospheric Deposition, Background Environments, Headwater Lake Catchments, Microfibres, Microplastics, Rainfall
An Emergent Model of the Return to Learn Process for Adolescents with Prolonged Concussion
Current literature on concussion management focuses primarily on the return to physical activity, while the return to learn process is less clearly understood. This knowledge gap is particularly problematic for adolescents, whose primary responsibility is academics. The present study sought to develop a more in-depth understanding of the return to learn process through the perspectives of adolescents who had sustained a concussion and their parents in in-person, semi-structured interviews. A substantive grounded theory of the return to learn process for adolescents that emerged from the data is provided. The basic model is consistent with many speculative, non-empirically based concussion management protocols, but extends these models by emphasizing the central role of parents in managing their child’s recovery process, highlighting the importance of role fulfillment within the concussion management network, and identifying the impact of the adolescent’s capacity and readiness for help-seeking. The results also highlight the vulnerability of concussed adolescents to losing their support structure as they move through key school transitions. Implications for educators, medical professionals, parents, and adolescents in the return to learn process are also discussed. Author Keywords: Adolescent, Concussion, Concussion Management, Multidisciplinary Management, Return to Learn, Return to School
Cytokinins in nematodes
To investigate cytokinins (CKs) in nematodes, CK profiles of a free-living Caenorhabditis elegans and a plant parasitic Heterodera glycines (soybean cyst nematode, SCN) were determined at the egg and larval stages. SCN had higher total CK level than C. elegans; however, CKs in SCN were mostly inactive precursors, whereas C. elegans had more bioactive forms. This is the first study to show that methylthiols are present in nematodes and may affect plant infection. In infectious SCN larvae, methylthiol levels were much higher than in eggs or C. elegans larvae. Furthermore, The CK profiles of SCN-susceptible and resistant Glycine max cultivars at three developmental stages revealed that, regardless of the resistance level, SCN infection caused an increase in root CKs. One resistant cultivar, Pion 93Y05, showed significantly high levels of bioactive N6-isopentenyladenine (iP) in the non-infected roots which indicated a potential role of CKs in soybean resistance to SCN. Author Keywords: Cytokinins, HPLC-MS/MS, Nematode, SCN resistance, Soybean
Academic Procrastination, Self-Regulation, Anxiety and Personality (ASAP)
Academic procrastination is analogous to a common cold: pervasive and with no established cure. Students experience repercussions that are not inclusive to academic performance, but rather, are experienced across mental, physical, social and emotional domains as well. While this necessitates treatment, much of the behaviour has yet to be explained. In the current study, a state approach was integrated to explore procrastination in terms of the Yerkes-Dodson paradigm. Procrastination was hypothesized to arise for one of two reasons: students are either too low or too high in anxiety. A sample of 847 Ontario undergraduate students completed measures of procrastination, state-anxiety, personality, and self-regulation. Results suggest 88% of students procrastinate regularly, and contrary to what was hypothesized, procrastination and anxiety were linearly related. Independent t-tests establish that relative to non-procrastinators, procrastinators are significantly more emotionally and biologically dysregulated and less socially integrated. Factor analysis demonstrated three central reasons contributing to procrastination, which were used as the basis to establish types of procrastination: social (n=61), self-doubt (n=70) and low-energy (n=76) procrastinators. Results indicate divergences across procrastination type with respect to personality as well as biological, affective and social domains. Findings also inform that the expression of procrastination, varies across student. Overall, findings suggest that academic interventions should acknowledge and address the variability among procrastinators. Author Keywords: ACADEMIC PROCRASTINATION, ANXIETY, PERSONALITY, SELF-REGULATION
Ligand Binding Properties of Giardia Flavohemoglobin
The parasitic protist Giardia intestinalis possesses flavohemoglobin (gFlHb), an enzyme that detoxifies nitric oxide to the less harmful nitrate, and is a potential target for antigiardial drugs that act as ligands to the iron of its heme cofactor. In this work, the binding constants KD of gFlHb, three active-site variants (Q54L, L58A, Y30F) and the E. coli flavohemoglobin (Hmp) towards cyanide, azide and several substituted imidazoles were measured by optical titration. Certain cases such as gFlHb and Hmp were studied further by isothermal titration calorimetry. Binding constants for cyanide and the imidazoles ranged from 2 to 100 M, with the highest affinities observed with for miconazole, a bulky substituted imidazole. Azide was a poor ligand, with binding constants between 0.48 and 26 mM. Among gFlHb and its mutants, L58A tended to have the highest ligand affinities, as mutation of the distal leucine to a less bulky distal alanine residue facilitates the access of the exogenous ligand to the heme iron. In contrast, the Q54L and Y30F variants had binding affinities that in most cases were similar to wild type, which suggests that the inability of their side chains to form hydrogen bonds to these ligands is not a significant factor in binding of imidazole ligands to the enzyme. Comparative results for Hmp and gFlHb ligand binding affinities revealed slight differences which might be explained by the presence of different residues in their active sites apart from their conserved residues. Author Keywords: Flavohemoglobin, Giardia intestinalis, Imidazole binding, Ligand binding, Nitrosative stress
Patterns of Vegetation Succession on Nickel-Copper Mine Tailings near Sudbury, Ontario
Natural establishment of vegetation on mine tailings is generally limited. Understanding the processes leading to vegetation germination and the survival mechanisms that vegetation species employ in these harsh environments is critical to future remediation efforts. As metalliferous mine tailings are generally nutrient-poor, high in harmful metals, and acidic, vegetation species require distinct mechanisms to germinate and survive in such harsh environments. In this study, edaphic and biotic factors linked to vegetation establishment and diversity were studied at two nickel-copper (Ni-Cu) tailings sites near Sudbury, Ontario. One site had experienced minimal treatment, and the second site was split into partial (hand-distribution of lime) and full (lime, fertilizer, seeding) treatment areas. Tailings were generally acidic, low in organic matter and “available” nutrients, and high in metals such as Al, Cu, Fe, and Ni, but these physical and chemical properties were extremely spatially variable. At both sites, vegetation was distributed in sparse patches, with the greatest diversity in treated areas. There was no clear link between metals and vegetation establishment/diversity at the sites. The primary limiting nutrients on the tailings were phosphorous (P) and potassium (K), and while there were areas of increased soil fertility at the sites, they were not clearly associated with increased vegetation diversity. Both traditional ecological succession and nucleation succession patterns were observed on the site, and the chief species associated with nucleation were primary colonizing trees such as B. papyrifera and P. tremuloides. The relationship between B. papyrifera nutrient retranslocation and tailings restoration was assessed and while B. papyrifera at the sites were deficient in P and K, the trees efficiently retranslocated both P and K during senescence. This research can provide insight into possibilities for future revegetation of similar tailings, enabling industry to make educated decisions when choosing where and how to revegetate, mimicking natural succession patterns. Author Keywords: Acid-mine drainage, Betula papyrifera, ecosystem health, metals, Sudbury, tailings
Investigation of Air Recirculation and Thermal Efficiency within a Climate Controlled Passage
Historically, entrances have been used for passage between two separate temperature environments, such as moving from inside to outside of a building. Energy loss through entrances is a cause for concern, as it has been known to increase energy consumption to replace the lost energy; and with the exchange of air masses and cold air entering the building, human discomfort may occur. In this research, thermal efficiency and air circulation within a Conventional Entrance (CE) and Climate Controlled Passage (CCP) are compared. A small scale model of the CE and CCP was constructed to examine forty-eight energy exchange conditions, emulating those found through an entrance between a temperature controlled lab and the model. Instruments such as a power meter, a flow explorer laser Doppler anemometer, and thermocouples were used to measure and compare the energy consumption, velocity vectors, and temperature energy within the entrance. Results indicate that the CCP did retain thermal energy compared to the CE. The CE developed sloped isotherm lines and air flow that enabled and maintained thermal exhaust. Conversely, the CCP developed horizontal isotherm lines and a two-layer density current to recirculate and retain thermal energy. The research demonstrates that it is possible to increase energy efficiency of entrances in many applications. Author Keywords: Air Recirculation, Building, Entrance, Oven, Thermal Energy Efficiency, Two-layer Density Current
Modelling Monthly Water Balance
Water balance models calculate water storage and movement within drainage basins, a primary concern for many hydrologists. A Thornthwaite water balance model (H2OBAAS) has shown poor accuracy in predicting low flows in the Petawawa River basin in Ontario, so lake storage and winter snow processes were investigated to improve the accuracy of the model. Lake storage coefficients, represented by the slopes of lake stage vs. lake runoff relationships, were estimated for 19 lakes in the Petawawa River basin and compared on a seasonal and inter-lake basis to determine the factors controlling lake runoff behaviour. Storage coefficients varied between seasons, with spring having the highest coefficients, summer and fall having equal magnitude, and winter having the lowest coefficients. Storage coefficients showed positive correlation with lake watershed area, and negative correlation with lake surface area during summer, fall, and winter. Lake storage was integrated into the H2OBAAS and improved model accuracy, especially in late summer, with large increases in LogNSE, a statistical measure sensitive to low flows. However, varying storage coefficients with respect to seasonal lake storage, watershed area, and surface area did not improve runoff predictions in the model. Modified precipitation partitioning and snowmelt methods using monthly minimum and maximum temperatures were incorporated into the H2OBAAS and compared to the original methods, which used only average temperatures. Methods using temperature extremes greatly improved simulations of winter runoff and snow water equivalent, with the precipitation partitioning threshold being the most important model parameter. This study provides methods for improving low flow accuracy in a monthly water balance model through the incorporation of simple snow processes and lake storages. Author Keywords: Lake Storage, Model Calibration, Monthly Water Balance, Petawawa River, Precipitation Partitioning, Snow Melt
Comparison of Dehydration Techniques for Acute Weight Management in Rowing
Mild sauna dehydration and fluid abstinence were investigated as weight loss strategies for lightweight rowers. Rowers (N=12) performed a power test, an incremental VO2max test, and a visuomotor battery: once euhydrated, once following sauna dehydration (SAU), and once following fluid abstinence and then sauna dehydration (FA). The percent body mass change (%BMC) achieved, %BMC attributable to sauna dehydration, and %BMC attributable to fluid abstinence were used within linear mixed effects models to predict hydration and performance variables. Sauna and overnight dehydration exerted indistinguishable effects on plasma osmolality, urine osmolality and thirst (p > .05). Fluid abstinence but not sauna dehydration was related to lower power production on the power test (b = 12.14W / 1%BMC, FA = 673.46 ± 79.50, SAU = 683.33 ± 72.08, p = .029), a lower total wattage produced on the incremental VO2max test (b = 4261.51W / 1%BMC, FA = 71029.58 ± 16256.56, SAU = 74001.50 ± 14936.56, p = .006), lower wattages at 2 mmol/L (b = 27.84W / 1%BMC, FA = 180.74 ± 40.27, SAU = 190.82 ± 50.79, p < .001) and 4 mmol/L (b = 20.45W / 1%BMC, FA = 221.90 ± 52.62, SAU = 238.89 ± 40.78, p = .002) blood lactate, and slower movement time on a visuomotor task (b = -38.06ms / 1%BMC, p = .004). Mild fluid abstinence but not sauna dehydration reduces rowing performance when two-hour rehydration is allowed. Author Keywords: crew, fluid, hydration, lightweight, sauna, weight


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