English
Near-road assessment of traffic related air pollutants along a major highway in Southern Ontario
The spatial and temporal variation in atmospheric nitrogen dioxide (NO2), ammonia (NH3), and 17 elements (V, Cr, Fe, Ni, Cu, Zn, As, Cd, Pb, Mg, Al, Ca, Co, Se, Sb, Mn, and Na) were measured at 40 road side locations along a ~250 km traffic density gradient of 40,000–400,000 vehicles on the King's Highway 401, in Ontario, Canada. Elemental concentrations were measured over a year, using moss bags as passive samplers, for four quarterly three-month exposure periods (October 2015 – October 2016). Gaseous NO2 and NH3 concentrations were measured using Willem's badge passive diffusive samplers for twelve one-week exposure periods (one per month: October 2015–October 2016). Dry deposition of nitrogen was estimated using the inferential method. There were significant linear relationships between NO2 and NH3 and average annual daily traffic (AADT) volumes across the study area; higher concentrations corresponded to higher volume traffic sites. Average NO2 concentrations at sites ranged from 23.5 to 73 μg/m3, with an annual average of 43.7 μg/m3. Ammonia ranged from 2.56 to 13.55 μg/m3, with an annual average of 6.44 μg/m3. There were significant quarterly variations in NO2, with concentrations peaking during the winter months. In contrast, NH3 showed no significant quarterly variation, but a slight peak occurred during the summer. Gaseous NO2 and NH3 were highly positively correlated (r = 0.63), suggesting a common emission source from traffic. Concentrations in exposed moss were determined by subtracting the total concentration of each metal in the exposed sample from the background concentration present in the moss. Relative accumulation factors (RAF) and contamination factors were also calculated to determine the anthropogenic influence on tissue concentrations in exposed moss. All metals showed elevated levels versus background concentrations, with all metals except Ni and Co showing considerable enrichment. The highest levels of contamination were from V, Cr, Fe, Zn, Cd, Sb, Pb and Na. Principal component analysis indicated 5 clear clusters of related elements, with PC1 accounting for 36.2% and PC2 accounting for 25.6% of the variance. Average annual daily traffic was significantly related to Cr, Fe, Cu, Sb, Mn, Al, and Na. Road side monitoring shows consistently higher concentrations than active monitoring sites located further from the edge of the road, indicating a need for increased road side monitoring in Ontario, Canada.
Assessing Emotion Processing Deficits in Youth: Validation of the Toronto Alexithymia Scale Adolescent Version
It is well-established that alexithymia in adulthood is a critical risk factor for numerous negative mental health and well-being outcomes. Although this area of research has begun to receive interest in earlier developmental stages, significant methodological limitations have been noted with current measures of alexithymia for adolescence. As such, the aim of the current thesis was to provide empirical evidence on the psychometric strength of a new adolescent measure of alexithymia, the Toronto Alexithymia Scale – Adolescent Version (TAS-A). Study 1 examined the construct validity of the TAS-A in relation to self and informant reported emotional intelligence (EI), while study 2 examined the predictive validity of the TAS-A in relation to adolescent problematic gambling and academic achievement. Adolescents completed self-reports of alexithymia, EI, and gambling behaviour, parents completed informant reports regarding their child's EI, and academic records were obtained. Confirmatory factor analyses revealed significant relationships between adolescent alexithymia, and self and informant reported EI, indicating significant overlap in constructs. Adolescent alexithymia was also shown to be a significant predictor of problematic gambling and academic achievement; however, some interesting gender differences were observed (a pattern of results reported consistently in the adult alexithymia literature). Results are discussed in terms of methodological and clinical implications during the vulnerable developmental transition of adolescence.
Author Keywords: adolescence, alexithymia, psychometrics
Tests of the Invasional Meltdown Hypothesis in invasive herbaceous plant species in southern Ontario
According to the Invasional Meltdown Hypothesis (IMH), invasive species may interact in their introduced range and facilitate future invasions. This study investigated the possibility that Alliaria petiolata, an invasive allelopathic herbaceous plant in Ontario, is facilitating invasions by additional alien species. Two allelopathic focal species were chosen for this study: the native Solidago canadensis and the invasive A. petiolata. Field surveys in southern Ontario that quantified plant biodiversity in plots that included one or both focal species revealed no support for the IMH, although fewer species co-existed with A. petiolata than with S. canadensis. A year-long recruitment experiment in Peterborough, Ontario, also produced results inconsistent with the IMH, although did provide some evidence that A. petiolata limited recruitment of other species. These results collectively show negative impacts on regional biodiversity by A. petiolata, even in the absence of an invasional meltdown.
Author Keywords: allelopathy, Alliaria petiolata, co-occurrence surveys, invasional meltdown hypothesis, invasive species, Solidago canadensis
Using a real-world chopping task to study motor learning and memory
Typically task interference is studied using reaching adaptation tasks (visuomotor rotation and/or force-field learning). Participants in these experiments are already experts at the base task (point-to-point, planar reaching) and their ability to adapt reaching to the imposed perturbation is studied. The pattern of data induced by the perturbation is used to make inferences about the nature and neural correlates of our learning and memory for reaching perturbations, specifically, and motor performance in general. We wanted to see if it is possible to demonstrate this same interference pattern using a novel vegetable-chopping task, where we can easily recreate natural performance settings using a task for which we can easily identify non-experts. Participants performed a chopping task in which they are asked to chop a sweet potato into 5 mm-wide slices, matching the beat of a metronome (120 bpm). Following this initial learning, participants were exposed to an interference condition. Participants then performed trials of the original task again. Interference was inferred if the second performance of the original task was impaired, compared to initial performance. Experiment 1 involved novice choppers, and either the force or frequency of chops was manipulated. Only the altered frequency task produced interference effects. In Experiment 2, competent and expert choppers had to manage either a faster or slower frequency. We found evidence for interference in competents, but not experts. These results support the idea that the vulnerability to interference of motor memory changes with practice, and so any inferences made about memory structure must take into account not only expert performance, but every level of skill.
Author Keywords: expertise, interference, motor learning, reaching adaptation
Towards a Critical Pedagogy of Globality: A Rhizo-Narrative Journey into the Global Self of the Teacher
In this thesis, I use "Trump's Wall" between Mexico and the US to resist Eurocentrism and the challenges Eurocentric pedagogy poses to the research-practitioner. In my method, I reimagine C. Alejandra Elenes' borderlands theory as a zone of empowerment within a multicultural Canadian classroom, and braid it in a hybrid assemblage with the rhizome.
The "rhizo-borderlands" assemblage uses selected field notes gleaned from my teaching practice to develop themes of a critical pedagogy of globality in personal, local and international dimensions. These are further braided with a "day-in-the-life" narrative of a fictionalized student (Ellie) who navigates her way towards a world literature classroom where the focus is The Kite Runner by Khaled Hosseini.
This assemblage affirms my belief that teaching and learning provides a context where students become "border crossers" and navigate points of intersection between their local and global selves, in order to develop intercultural competencies.
Author Keywords: Action Narrative, Critical Pedagogy, Rhizomes
Socio-Ecology and the Sacred: A Comparative Study of Entanglement and Natural Sites in Tropical Asia
Within the complex socio-ecological systems of South and Southeast Asia, ancient sacred natural sites were created by, and imbued with, cultural and ideological values. These landscapes are liminal spaces or threshold environments between cultivated areas and wilder spaces; the practice of creating and maintaining them persists from ancient to modern times. This thesis examines sacred natural sites in three early state formations from 800 – 1400 CE: the Khmer (Cambodia), the Sinhalese (Sri Lanka) and the Chola (South India), why they persisted over time, and what significance they held. Several ancient sacred natural sites are active parts of societies today, and the ones chosen for this study span several categories: mountains, rivers, forests/groves, and caves. Using the paradigm of entanglement theory in a comparative context, this thesis analyzes sacred natural sites acting as key socio-ecological nodes enmeshed in complex dependent relationships within the landscapes of the South and Southeast Asia.
Author Keywords: Comparative study, Entanglement theory, Sacred natural sites, Socio-ecological systems, South Asia, Tropical Societies
The Effects of Geographic Factors on the Wild Harvest of Large Mammals across North America
While the harvest of mammals is monitored in each jurisdiction across Canada and the USA, there has been no analysis of this wild harvest at a continental scale across North America. The recreational wild harvest of large mammals varies geographically across North America, and I hypothesized that this variation is influenced by both anthropogenic and other environmental factors on the landscape. I tested this hypothesis using annual harvest tallies collected by Conservation Visions Inc. for mammals for each state, provincial, and territorial jurisdiction in Canada and the USA. I built multiple additive models of the harvest, in one harvest year, 2015 – 2016, to test for landscape gradients that explain the variation in harvest levels for seven large mammal species: white-tailed deer (Odocoileus virginianus), black bear (Ursus americanus), bighorn sheep (Ovis canadensis), elk (Cervus canadensis), mule deer (Odocoileus hemionus), pronghorn (Antilocapra americana), and moose (Alces alces). I built these models from a suite of nine putative predictor variables that comprised landcover, human footprint, and evapotranspiration. For all large mammal species except for pronghorn, anthropogenic influence had a positive effect on the wild harvest density, consistent with the idea that the proximity of human populations and roads are important for fostering wild harvest activity by providing hunters access to hunting areas. The harvest of white-tailed deer, elk, and pronghorn were negatively affected by vegetation structure, urbanization, and primary productivity, respectively. Understanding the recreational wild harvest at a broad-spatial scale provides a unique perspective of the North American model of wildlife conservation and spurs future comparative analyses of the wild harvest across spatial scales.
Author Keywords: Anthropogenic Influence, Hunting, Large Mammals, Primary Productivity, Vegetation Structure, Wild Harvest
The Experience o Being Jewish in a Small Jewish Community: A Qualitative Analysis
This thesis explores the experience of Jewish individuals living in a small Jewish community in an urban centre of less than 100,000 in Ontario, Canada. The central question I explore is the ways in which Jewish individuals in a small community enact and perform their identity. What are some of the challenges and obstacles faced by Jews in a small community and what kinds of compromises must be made to accommodate members of the community? Do the benefits of living in a small Jewish community outweigh the shortcomings? This thesis examines how Jewish identity is constructed, maintained and challenged within a smaller urban centre.
I begin with a brief historical background of the Jewish presence in Canada. I will look through the lens of Jewish identity within the framework of Canadian multiculturalism, and reasonable accommodation. Jewish identity will then be explored through an intersectional framework. Using qualitative interviews conducted with Jewish individuals, an analysis of common themes and issues pertaining to Jewish identity and maintenance is explored. These themes include Religious observance, cultural identity, Jewish customs and traditions, social action and advocacy. These themes were divided between those of a more individual nature and those of a more communal nature.
For participants in this research, managing and maintaining their Jewish identity consisted of balancing their religious and cultural life with their social, work, and other obligations outside the sphere of Jewish identity. The relationship between White identity and Jewish identity is a focal point of study. The synagogue/community centre acts as the primary place in which to express, share, and connect with other Jews.
Author Keywords: Assimilation, Community, Intersectionality, Jewish Identity, Multiculturalism, Reasonable Accommodation
Risk of Mortality for the Semipalmated Plover (Charadrius semipalmatus) Throughout Its Life Cycle
Three long-term mark and recapture/resight data sets of individually marked
Semipalmated Plovers (Charadrius semipalmatus) were analyzed using Cormack-Jolly-
Seber models. Data came from two breeding populations (Churchill, Manitoba, Canada,
n=982, and Egg Island, Alaska, USA, n=84) and one overwintering population
(Cumberland Island, Georgia, USA, n=62). For Alaska and Georgia, time-invariant
models were best-supported, giving annual survival estimates of 0.67 (95%C.I.: 0.58-
0.76) and 0.59 (95%C.I.: 0.49-0.67) respectively. Data from Manitoba supported a timedependent
model: survival estimates varied from 1.00 to 0.36, with lowest estimates from
recent years, supporting observations of local population decline. Seasonal survival
analysis of the Georgia population indicated lower mortality during winter (monthly
Φoverwinter: 0.959, 95%CI: 0.871-0.988; for 6 month period Φoverwinter: 0.780 (0.440-0.929))
than during combined breeding and migratory periods (monthly ΦBreeding+Migration: 0.879
(0.825-0.918); for 8 month ΦBreeding+Migration: 0356 (0.215-0.504)). I recommend, based on
high resight rates, continued monitoring of survival of wintering populations, to
determine potential range-wide population declines.
Keywords: survival, longevity, mortality, shorebird, overwinter, breeding, migration, life
cycle
Author Keywords: life cycle, longevity, mortality, non-breeding, shorebird, survival
Exploring the Scalability of Deep Learning on GPU Clusters
In recent years, we have observed an unprecedented rise in popularity of AI-powered systems. They have become ubiquitous in modern life, being used by countless people every day. Many of these AI systems are powered, entirely or partially, by deep learning models. From language translation to image recognition, deep learning models are being used to build systems with unprecedented accuracy. The primary downside, is the significant time required to train the models. Fortunately, the time needed for training the models is reduced through the use of GPUs rather than CPUs. However, with model complexity ever increasing, training times even with GPUs are on the rise. One possible solution to ever-increasing training times is to use parallelization to enable the distributed training of models on GPU clusters. This thesis investigates how to utilise clusters of GPU-accelerated nodes to achieve the best scalability possible, thus minimising model training times.
Author Keywords: Compute Canada, Deep Learning, Distributed Computing, Horovod, Parallel Computing, TensorFlow