Graduate Theses & Dissertations


Retrograde Amnesia of Fear Memories Following Pentylenetetrazol Kindling
Memories pertaining to fearful events are some of the most salient and long-lasting memories, as they are critical to the survival of an organism. Seizures induce aberrant changes within temporal lobe and limbic brain structures that are critical for supporting fear memories. Seizures can occur at any time; therefore, it is imperative that research address how seizures impact previously learned information. The present series of experiments demonstrate that pentylenetetrazol-kindling induces retention deficits of previously acquired context fear memories in male rats. Kindling induced subsequent fear learning deficits but did not impact spatial learning. Additionally, following kindling, volumetric increase was observed within the hippocampal subfield CA3, as well as increased neural activation within the hippocampal subfield CA1. The results of this work suggests that chronic seizures can alter the function of neural networks important for supporting and retrieving previously acquired memories. Author Keywords: amygdala, anterograde amnesia, context fear conditioning, hippocampus, retrograde amnesia, seizures
Racism in Argentina and the Blackness Problem. The Change in Perception of Afro-Descendants in Buenos Aires and the New Dimensions of Blackness in Argentina (1880-1930)
This thesis examines racism in Argentina between 1880 and 1930. The governing elite's efforts to whiten the Argentine population at the end of the nineteenth century led to the erasure and discrimination of anyone who did not have Caucasian features: Afro-descendants, mulattos, mestizos, and creoles. However, in the 1930s, whitening policies proved to have limited success. On the one hand, Afro-descendants were praised by the middle and lower classes of Buenos Aires; on the other hand, the Great Depression's effects made it clear that the Argentine population was made up of an ethnic mixture that had much darker skin tones than the whitening elite preferred. This work will show how the impact of the 1930s global crisis, as well as the enthusiasm for Afro-descendants, reinforced the racism that still existed, and will demonstrate that blackness became more than a racial but also a class connotation. Author Keywords: Afro-descendants press, Blackness in Argentina, Buenos Aires Press, Cultural Constructions, Popular Blackness, Racial Identity
Story is Medicine
This is a story within a story that spans over a hundred years and four generations. It takes the reader from war-torn Russia during a famine to the urban streets of Toronto and then to the Canadian North. The story is a memoirette, or a ‘not quite long enough, but almost a memoir’ of a mother’s journey navigating life after her son discloses his addiction to Fentanyl. The mother finds little if any support from family, friends or conventional support programs and instead turns to her oma’s harrowing stories of survival as a source of knowledge, strength and medicine. The analysis explores storytelling as a legitimate method of learning, pedagogy and research. It explores the concept of story as medicine through Etuaptmumk. A Two-Eyed Seeing framework created by Mi’kmaq elders in 2004 (Sylliboy, Latimer, Marshall & McLeod, 2009). The power of the narrative is discussed through ‘Western’ and ‘Indigenous’ lenses. Author Keywords: addiction, Etuaptmumk, Fentanyl, story as medicine, story as pedagogy, Two-Eyed Seeing
Interactome study of the Giardia intestinalis nuclear localized cytochrome b5
Giardia intestinalis is a waterborne enteric parasite that lacks mitochondria and the capacity for heme biosynthesis. Despite this, Giardia encodes several heme proteins, including four cytochrome b5 isotypes (gCYTB5-I – IV) of unknown function. The aim of this thesis is to gain insight into the function of the Giardia cytochrome b5 isotype III (gCYTB5-III) that is found in the nucleus, as first reported by our laboratory using immunofluorescence microscopy experiments with an isotype-III specific antibody. Nuclear localization of isotype-III is supported by two of my experiments: i) immunoblot analysis of crude cytoplasmic and nuclear enriched fractions of Giardia trophozoites; ii) association of gCYTB5-III with the insoluble fraction of Giardia lysates crosslinked with formaldehyde is reversed by DNase I treatment. To gain an understanding of the possible roles of gCYTB5-III, I performed immunoprecipitation (IP) experiments on lysates from Giardia trophozoites to identify its protein partners. Mass spectroscopy analysis of the immunoprecipitate identified proteins localized to the nucleus (RNA polymerase, DNA topoisomerase, histones, and histone modifying enzymes). Intriguingly, over 40% of the known mitosomal proteome, which functions in iron-sulfur (Fe-S) cluster assembly was also associated with gCYTB5-III. One of these proteins, the flavoenzyme GiOR-1, has been shown to mediate electron transfer from NADPH to recombinant gCYTB5-III. These IP results provide evidence that GiOR-1 and gCYTB5-III interact in vivo, and furthermore, suggest that some proteins in the mitosome could interact with those in the nucleus. I also found that DNA stress, caused by low concentrations of formaldehyde (0.1 – 0.2%) resulted in the increased expression of gCYTB5-III. Collectively these findings suggest a role of gCYTB5-III in Giardia's response to DNA stress and perhaps the formation of Fe/S clusters. Author Keywords: cluster, cytochrome, heme, iron, mitosome, nuclear
Behavioural ecology and population dynamics of freshwater turtles in a semi-urban landscape at their northern range limit
Species are faced with a variety of challenges in the environment, including natural challenges, such as variability in ambient temperature, and anthropogenic threats, such as habitat transformation associated with urbanisation. Understanding how animals respond to these kinds of challenges can advance the field of behavioural ecology and guide management decisions for wild species. Yet, we still have limited understanding of the extent of natural and human-caused impacts on animal behaviour and population dynamics, and lack robust assessment of behaviour in free-ranging animals. Using novel miniaturised biologging technologies, I characterised and validated behaviour in two freshwater turtle species: Blanding’s turtles (Emydoidea blandingii) and Painted turtles (Chrysemys picta). Further, I investigated how these two ectothermic species navigate a thermally heterogeneous landscape near their northern range limit, by comparing selected and available ambient temperatures. I showed that turtles preferred locations that were, on average, warmer and less variable in temperature than the available environment, and that this thermal sensitivity was greatest early in the year, and at fine spatial scales that likely matched the species' perception of the environment. Lastly, I assessed whether urban development was compatible with long-term viability of a Blanding’s turtle population, by monitoring habitat change and turtle survival over one decade of ongoing residential and road development. I found that Blanding’s turtle habitat quantity and connectivity declined in the area, which coincided with high road mortality and severe declines in turtle survival and population size, especially in adult females. I concluded that urban development and current road mortality rates are incompatible with the long-term viability of this at-risk turtle population. Overall, my findings demonstrate the importance of variation in the thermal environment and anthropogenic impacts on habitat in shaping the behaviour and population dynamics of this species-at-risk. Author Keywords: animal behaviour, biologging, ectotherms, habitat selection, temperature, urbanisation
Landscape and its Discontents - Art and Ruins, a Critical Topography in Word and Image
From Altdorfer and Poussin to Cézanne, Monet and to the Group of Seven, landscape has been a focal point of artistic inspiration for most of what we think of as modern art history. In contemporary times the concept and representation of landscape has shifted from visions of an idealized and exalted place to notions of the landscape as a ruins and site of ecological disaster. Because of this seismic inversion, artists are no longer solely making visual the beauty and serenity of nature but are rather finding novel ways of problematizing it and incorporating themes of its eventual disappearance, its inescapable transformation into ruins. The following dissertation puts forward a critical topographical study of three sites and three different artists who deal with this new found relationship to landscape. The three landscapes are located in different parts of the world and from different artistic contexts yet showing that they retain an aesthetic and conceptual character that links them together is part of the work of the dissertation. The first site is El Sol del Membrillo, a film by Víctor Erice in which the filmmaker chronicles painter Antonio Lopez García’s attempts to paint the ephemeral, he attempts to paint that which is in the act of disappearing. The second site is The Mill St Cemetery in Cambridge, England where artist Gordon Young has contributed a work of public art titled Bird Stones that blurs the line between landscape, sculpture, monument and artwork. The third and final site is Tommy Thompson Park in Toronto, Canada that presents itself as an ecology park of retrieval, recovery and as a public art space. My investigation of this last regional research site is offered both as a chapter and as a videography about wilderness as wasteland. Author Keywords: Aesthetics, Anthropocene, Art, Cinema, El Sol del Membrillo, Toronto: The Leslie Spit
Fall Migratory Behaviour and Cross-seasonal Interactions in Semipalmated Plovers (Charadrius semipalmatus) Breeding in the Hudson Bay Lowlands, Canada
I used the Motus Wildlife Tracking System to monitor the fall migration behaviour and assess the underlying drivers of migration strategy in a small shorebird, the Semipalmated Plover (Charadrius semipalmatus), breeding at two subarctic sites: Churchill, Manitoba and Burntpoint Creek, Ontario, Canada. Semipalmated Plovers from both sites departed breeding areas between mid-July and early August, with females preceding males and failed breeders preceding successful breeders. Migrants showed between and within-population variation in migration behaviour, though birds from both sites tended to follow interior or coastal routes and congregated in three major stopover regions along the mid-Atlantic coast of North America. I found that later-departing birds had initial flight tracks oriented more toward the south, faster overall ground speeds, were less likely to stopover in North America, and stopped at lower latitudes, suggesting that later-departing individuals use aspects of a time-minimizing strategy on fall migration. My findings emphasize the importance of the mid-Atlantic coast for Semipalmated Plovers and establish connectivity between sites used during breeding and migration. Author Keywords: Breeding, Migration, Motus, Semipalmated Plover, Shorebird, Stopover
Food insecurity among racialized international students
The notion that food insecurity only occurs in the absence of food is prevalent in society. This perception is too narrow and insufficient to capture the diverse manifestations and experiences of food insecurity. In this thesis, I adopt a more expansive approach to examine food (in)security through the lenses of adequacy, quality, and availability of culturally relevant food. I look specifically at the experiences of racialized international students from diverse backgrounds, to empirically ground this approach to understanding food (in)security. Drawing on both quantitative and qualitative data, this study explores the perceptions and real-life experiences of racialized international students who study at Trent University and University of Toronto. These two institutions were selected based on cultural diversity and variation, proximity to culturally appropriate food and the cost involved in accessing culturally appropriate food. Beyond that, I examine structural and policy elements that may be exacerbating the challenge of food security among this category of students. Clearly, issues related to food insecurity and hunger within all spatial configurations are urgent, however, there is a scarcity of literature that zeroes in on the experiences of racialized international students specifically. In the wake of the dramatic internationalization of post-secondary Canadian schools, issues of foreign students’ welfare cannot be overlooked, hence, I narrowed my research lenses to study the character of racialized international students’ inadequate access to culturally appropriate food. Upon analyzing the survey data gathered from 107 racialized international students coupled with semi-structured in-depth interviews with 8 racialized students, I found evidence that culturally appropriate foodstuffs were not abundant in supply for racialized international students. Consequently, the low supply of this category of foodstuffs translates into higher levels of prices which deter racialized international students from making adequate purchases to meet their taste and preference. As part of the findings, the students mentioned that the high cost of tuition, as well as other school-related expenditures are structural policy barriers that leave them with meagre amounts of income to spend on culturally appropriate food items. Under such circumstances, racialized international students are left with the option of purchasing fewer quantities of culturally relevant foodstuffs that meet their daily nutritional requirements. The study further revealed that the challenge of food insecurity poses a threat to the academic achievement and psycho-social well-being of affected students. In addressing these challenges, I propose that the government as well as the school authorities should consider reducing the tuition fees to lessen the financial burden on students. Apart from that, stocking grocery stores and creating culturally appropriate food supply centers in and around school campuses may be helpful. Also, the international offices of universities should intensify welfare programs that entail periodic needs assessment of international students. This will offer the school authorities timely support services to students as and when it is needed. In conclusion, I wish to state that this study seeks to add to the recently growing strand of literature that examines the intersectionality between internationalization of post-secondary schools and food insecurity. The findings provide important and preliminary evidence underpinning the experiences of racialized international students with the phenomenon of food insecurity, thereby providing a point of departure for additional research on the broader nature of intersections between food insecurity and racialization. Author Keywords: Canada, Culture, Food insecurity, International Students, Race, Universities
Using the Same Language, but Meaning Different Things
Two dominant narratives emerging throughout the war were the national narrative––that is, the narrative of the war as articulated by the British nation via texts such as political speeches, recruitment posters, and popular music–– and the poetic narrative––that is, the narrative of the war emerging from poets, specifically battlefront poets for the sake of this thesis. One hundred years since World War One, these two narratives are often conceptualized as mutually exclusive, even antithetical to one another. This thesis brings these diverse narratives into conversation with one another by investigating how they both draw on the same rhetorics and yet use these rhetorics to differing ends. Interestingly, the rhetorics employed by both narratives throughout the war endure in contemporary remembrance practices in Britain today. By investigating how each narrative draws on and employs the same rhetorics, this thesis both contextualizes and complexifies contemporary interpretations of contemporary remembrance practices. Author Keywords: Battlefront Poetry , Britain, Narrative, Remembrance, Rhetoric, World War One
Expression of Giardia intestinalis flavoenzyme GiOR-1 and characterization of its electron transfer properties
Giardia intestinalis possesses four isotypes of cytochrome b5 (gCYTB-I-IV) that differ from their mammalian counterparts, suggesting different functions in this protozoan parasite. Although the recently discovered Giardia flavoenzyme, GiOR-1, reduces these cytochromes, its properties have not been thoroughly studied, owing to the difficulty in its expression. Here I describe successful conditions for expression of GiOR-1 using autoinduction. GiOR-1 is obtained with flavins bound as indicated by its UV-visible spectrum. Its ability to catalyze electron transfer from donors (NADH, NADPH) to acceptors (oxygen, ferricyanide, cytochrome c, gCYTB5-III) were studied in spectrophotometric rate assays. NADPH is the preferred electron donor, while cytochromes are the preferred electron acceptors. Interestingly, the His-tag used to purify gCYTB5-III decreases its reaction rate with GiOR-1, as an untagged version has slightly faster rates. These findings establish the appropriate conditions for further studies on GiOR-1, including the identification of endogenous electron acceptors. Author Keywords: Autoinduction, Cytochrome b5, Cytochrome P450 oxidoreductase, Giardia intestinalis, GiOR-1, Polyhistidine tag
Prescription Drugs
Medication used to treat human illness is one of the greatest developments in human history. In Canada, prescription drugs have been developed and made available to treat a wide variety of illnesses, from infections to heart disease and so on. Records of prescription drug fulfillment at coarse Canadian geographic scales were obtained from Health Canada in order to track the use of these drugs by the Canadian population. The obtained prescription drug fulfillment records were in a variety of inconsistent formats, including a large selection of years for which only paper tabular records were available (hard copies). In this work, we organize, digitize, proof and synthesize the full available data set of prescription drug records, from paper to final database. Extensive quality control was performed on the data before use. This data was then analyzed for temporal and spatial changes in prescription drug use across Canada from 1990-2013. In addition, one of major research areas in environmental epidemiological studies is the study of population health risk associated with exposure to ambient air pollution. Prescription drugs can moderate public health risk, by reducing the drug user's physiological symptoms and preventing acute health effects (e.g., strokes, heart attacks, etc.). The cleaned prescription drug data was considered in the context of a common model to examine its influence on the association between air pollution exposure and various health outcomes. Since, prescription drug data were available only at the provincial level, a Bayesian hierarchical model was employed to include the prescription drugs as a covariate at regional level, which were then combined to estimate the association at national level. Although further investigations are required, the study results suggest that the prescription drugs influenced the air pollution related public health risk. Author Keywords: Data, Error checking, Population health, Prescriptions
Developing Social-Emotional Competencies in Youth
Trait Emotional Intelligence (TEI) plays an important role in the health and wellness of children and adolescents. Not surprisingly, the literature on TEI and youth has expanded dramatically. Although the quality of this work continues to be uneven due to the continued proliferation of TEI-related measures with questionable psychometric features. One over-looked TEI measure in the field is the short form developed for the Emotional Quotient Inventory Youth Version (EQ-i:YV-S). The core goal of Study 1 was to examine the overall reliability and validity of the EQ-i:YV-S. The aim of Study 2 was to evaluate the utility of the EQ-i:YV-S as a measure of the effectiveness of a new school-based social and emotional learning program for elementary school students. Results from Study 1 demonstrated that the EQ-i:YV-S had good internal reliability, 6-month test-retest reliability, and convergent validity. Study 2 found that Total EI and most key EI-related dimensions had significant improvement from pretest to post test on the EQ-i:YV-S. These findings have important implications for TEI measurement in youth and the effectiveness of school-based psychoeducational programming for TEI, with the EQ-i:YV-S as a viable option for research in this area. Author Keywords: emotional intelligence, psychoeducational programming, social-emotional competencies


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