Graduate Theses & Dissertations


Comparing Biological Responses to Contaminants in Darters (Etheostoma spp.) Collected from Rural and Urban Regions of the Grand River Watershed, Ontario
Urban and agricultural activities may introduce chemical stressors, including contaminants of emerging concern (CECs) and current use pesticides (CUPs) into riverine systems. The objective of this study was to determine if fish collected from sites in a river show biomarkers of exposure to these classes of contaminants, and if the biomarker patterns vary in fish collected from urbanized and agricultural sites. The watershed selected for this study was the Grand River in southern Ontario, which transitions from areas dominated by agricultural land use in the north to highly urbanized locations in the southern part of the watershed. Rainbow darters (Etheostoma caerluem) and fantail darters (Etheostoma flabellare) were collected from the Grand River in June, 2014 for biomarker analysis from two urbanized sites and three agricultural sites (n=20 per site). Over the same period of time, Polar Organic Chemical Integrative Samplers (POCIS) were deployed for 2 weeks at each site to monitor for the presence of CUPs and CECs. The amounts of the target compounds accumulated on POCIS, determined using LC-MS/MS were used to estimate the time weighted average concentrations of the contaminants at each site. Data on the liver somatic index for darters indicate site-specific differences in this condition factor (p<0.05). Significant differences in the concentrations of thiobarbituric acid reactive substances (TBARS) in gill tissue (p<0.05) indicate differences in oxidative stress in fish collected from the various sites. Measured concentrations of ethoxyresorufin-O-deethylase (EROD) in liver tissue were significantly different between sites (p<0.05), indicating differences in CYP1A metabolic activity. Finally, acetylcholinesterase (AChE) activity in brain tissue was significantly different between fish from rural and urban sites (p<0.05). The analysis of these biomarkers indicates that fish may be experiencing different levels of biological stress related to different land uses. These data may be useful in developing mitigation strategies to reduce impacts on fish and other aquatic organisms in the watershed. Author Keywords: AChE, Biomarker, Darter, EROD, POCIS, TBARS
Comparative efficacy of eDNA and conventional methods for monitoring wetland anuran communities
Identifying population declines and mitigating biodiversity loss require reliable monitoring techniques, but complex life histories and cryptic characteristics of anuran species render conventional monitoring challenging and ineffective. Environmental DNA (eDNA) detection is a highly sensitive and minimally invasive alternative to conventional anuran monitoring. In this study, I conducted a field experiment in 30 natural wetlands to compare efficacy of eDNA detection via qPCR to three conventional methods (visual encounter, breeding call, and larval dipnet surveys) for nine anuran species. eDNA and visual encounter surveys detected the greatest species richness, with eDNA methods requiring the fewest sampling events. However, community composition results differed among methods, indicating that even top performing methods missed species detections. Overall, the most effective detection method varied by species, with some species requiring two to three methods to make all possible detections. Further, eDNA detection rates varied by sampling season for two species (A. americanus and H. versicolor), suggesting that species-specific ecology such as breeding and larval periods play an important role in eDNA presence. These findings suggest that optimized monitoring of complex anuran communities may require two or more monitoring methods selected based on the physiology and biology of all target species. Author Keywords: amphibian, anuran, conventional monitoring, eDNA, environmental DNA, species richness
Comparative Studies in Tropical Epicentres in Southeast Asia
From ca. 800-1400 CE, low-density agrarian states dominated Southeast Asia, their authority emanating from their epicentres at places such as Angkor in Cambodia, Bagan in Myanmar, and Sukhothai in Thailand. These epicentres were the setting for numerous structures, activities, and stakeholders that became integral for the perpetuation of the state. These states and their epicentres declined and collapsed around the same time. As part of a larger project (the Socio-ecological Entanglement in Tropical Societies (SETS Project), the aim of this thesis is to add to our understanding of entanglement, resilience, and collapse in Southeast Asia. Using a relatively new method that combines resilience and entanglement theories, this thesis presents a view of epicentral entanglements and vulnerabilities that eventually contributed to the collapse of these societies. The results indicate that overextended socio-ecological systems and their growing entanglements created a loss of resilience and, when faced with change in these systems, collapse. Author Keywords: Angkor, Bagan, Entanglement Theory, Resilience Theory, Southeast Asia, Sukhothai
Community, Complexity, and Collapse
The city-state of Minanha, located in west central Belize, reached its zenith and most culturally complex stage by the Late Classic period, 675-810 AD. Only a century later, its royal court “collapsed”. The Contreras Valley is a small farming community located in a settlement zone south of Minanha. Decades of research at Minanha and the analysis of artifact frequencies from commoner households allow for a better understanding of the intra- and inter-community social practices occurring at the site of Contreras Valley and within the greater Minanha area. An Archaeology of Communities as well as Resilience Theory frameworks are utilized to explore the integrative social, political, and economic strategies of this commoner population. These theories are used to better understand the developmental history of the royal court from the perspective of the peripheral commoners, who sustained a population while the royal court disintegrated. Furthermore, this thesis focuses on the intersection of resilience and communities, and how the Contreras Valley experienced phases of resilience as well as vulnerability throughout its history. The resilience of this group of individuals will generate an increased cognizance of how a community copes with and continues to thrive in a climate of political chaos and instability. Author Keywords: Ancient Maya, Archaeology, Archaeology of Communities, Artifact frequencies, Resilience Theory, Settlement pattern studies
Community and conservation
Faced with the intersecting environmental crises of the 21st century, conservation organizations are searching for practices that produce better, more sustainable outcomes. However, they have often relied on forms of conservation which shore up rather than disrupt settler relationships to land in the form of fortress conservation and assumptions about the human-nature dualism. In this thesis, I examine a local land trust that intends to include community[-based] conservation into its conservation practices. In particular, I explore how the organization’s volunteers understand and construct the relationship between community and conservation, and the ways this might impact operations. Using a community-based research approach, interviews (n=17) were conducted. The findings indicate that the volunteers are demographically homogenous, leading to a homogenous, Western-science informed understanding of community[-based] conservation. This perspective views involvement of community as a direct trade-off with optimal ecological goals. As the volunteers wield uncommon power in organizational governance, difference in opinions toward missions or operations could lead to constraints on the organization. This study contributes to larger academic discourses on environmental volunteers, land trusts, and frames of conservation, and provides tangible recommendations to an organization attempting to include community[-based] conservation in its practices. Author Keywords: community-based conservation, environmental governance, environmental volunteers, frames of conservation, land trusts, power
Community Coalescence and Regional Geospatial Trends of Ceramic Decorative Variation in Late Woodland Northern Iroquoia
This case study focuses on geospatial patterns of decorative variation in pottery assemblages from 234 Northern Iroquoian village communities, occupied between ca. 1350–1650 CE. Previous interpretations of these assemblages’ ceramic decorative variability have been based on the assertion that potters from these communities used collar decorative motifs as communicative social signals. However, they did not consider whether these geospatial decorative patterns could simply reflect the outcome of stochastic macroscale social learning processes driven solely by probabilistic information exchange between closer neighboring communities. Cultural transmission, the theoretical framework applied here, is well-suited to address this perspective. Thus, the primary research question of this case study is, “Are the expected outcomes of random copying processes sufficient to explain the range of geospatial ceramic decorative variability observed across Northern Iroquoia?” Random copying processes are the stochastic, probabilistic social learning mechanisms driving the collective decisions of multiple communities, making up one side of the “random-selective copying spectrum.” When the decorative decisions of multiple communities are collectively guided by shared ideas (such as, potentially, symbolic communication structures), they become subsumed under the broad umbrella of “selective copying” processes. The social learning mechanisms involved on both sides have predictable geospatial and structural ranges of ceramic decorative patterning. The goal of this case study was thus to evaluate the range of patterning in Northern Iroquoia, both generally as well as at narrower temporal and spatial scales. Ultimately, region-specific temporal trends in selective copying processes seeming to reflect recently established temporal trajectories of community coalescence were identified. Author Keywords: coalescence, cultural population structure, cultural transmission, isolation by distance, Northern Iroquoia, social signaling
Commonality of Enemies
Carlism and anarchism were revolutionary social movements that acquired significant popular support during the most intensive period of modernization in Spain (mid 19th to mid 20th centuries). It was noted but not well explored by contemporaries and historians that these enemies were similar in their hostility towards modernization and in their intense idealism. This thesis compares the two movements in order to determine the nature of their commonality and what this suggests about ideological enemies. A range of sources were consulted, including scholarship on modern Spain, biographical information on individuals who converted from Carlism to anarchism and contemporary print media. It was concluded that they were produced by the same destabilizing processes of disentailment and industrialization, which drew the working classes towards proposals that would have otherwise seemed implausibly utopian. The thesis further suggests that they were uniquely idealistic, in that they put moral integrity before the success of their cause. Author Keywords: anarchism, Carlism, enemy other, modernization, Modern Spain, social movements
Combinatorial Collisions in Database Matching
Databases containing information such as location points, web searches and fi- nancial transactions are becoming the new normal as technology advances. Conse- quentially, searches and cross-referencing in big data are becoming a common prob- lem as computing and statistical analysis increasingly allow for the contents of such databases to be analyzed and dredged for data. Searches through big data are fre- quently done without a hypothesis formulated before hand, and as these databases grow and become more complex, the room for error also increases. Regardless of how these searches are framed, the data they collect may lead to false convictions. DNA databases may be of particular interest, since DNA is often viewed as significant evi- dence, however, such evidence is sometimes not interpreted in a proper manner in the court room. In this thesis, we present and validate a framework for investigating var- ious collisions within databases using Monte Carlo Simulations, with examples from DNA. We also discuss how DNA evidence may be wrongly portrayed in the court room, and the explanation behind this. We then outline the problem which may occur when numerous types of databases are searched for suspects, and framework to address these problems. Author Keywords: big data analysis, collisions, database searches, DNA databases, monte carlo simulation
Cognitive and Affective Theory of Mind in Children and Young Adolescents
Recently, a distinction has been made between cognitive theory of mind, the ability to make inferences about other's beliefs and thoughts, and affective theory of mind, the ability to make inferences about other's emotional states. The purpose of this study is to determine if the distinction between cognitive and affective theory of mind is developmentally appropriate and whether the relation between language and theory of mind is maintained when cognitive and affective theory of mind are examined separately. The sample consisted of 20 children aged 6 to 9 years, and 27 children aged 11 to 15 years. Results showed that the older group outperformed the younger group on both cognitive and affective theory of mind, and that different aspects of language were related to each type of theory of mind. This suggests the distinction between cognitive and affective theory of mind may in fact be valid in this age range. Author Keywords: Affective Theory of Mind, Cognitive Theory of Mind, Development, Language
Cognitive Inefficiencies in Adolescents with Eating Disorders
Eating Disorders (ED) are notoriously difficult to treat due, in part, to commonly observed inefficiencies in cognitive flexibility and central coherence, which are believed to maintain disordered cognitions and behaviours and negatively impact prognosis. Cognitive remediation therapy (CRT) has recently been used effectively with adults with ED; however, evidence among adolescents is limited. The present study explored change in flexibility and central coherence in a group of 23 adolescent ED inpatients (M = 16 years, SD = 0.95). All participants received a comparable dose of ED treatment. Participants were split into two groups for comparison: the CRT group (n = 15) received CRT in addition to TAU; and a TAU group for control (TAU; n = 8). Improvements in flexibility and central coherence were superior in the CRT group, suggesting that CRT is a potentially useful treatment for adolescents with AN as part of an overall psychosocial rehabilitation program. Author Keywords: anorexia nervosa, central coherence, cognitive flexibility, cognitive remediation, eating disorders, set shifting
Cluster Approach Applied to the One-Dimensional Anderson-Hubbard Model
S. Johri and R. Bhatt developed a real-space renormalization group approach aimed at extracting the localized single-particle eigenstates of the Anderson model from a large system by identifying clusters of resonant site potentials. E. Campbell generalized this real-space renormalization group approach using standard perturbation theory. Both approaches were intended to approximate the single-particle density of states of the Anderson model. In this thesis, we aimed to test the potential of applying a similar real-space renormalization group approach to calculate the density of states of the interacting Anderson-Hubbard model. Our interest in the density of states of this model is due to a V-shaped zero-bias anomaly in two-dimensional systems. A real-space renormalization group approach is best applied to a one-dimensional system. We found that the zero-bias anomaly is not V-shaped in one-dimension. To test the potential of a real-space renormalization group approach, we used the cluster approach which is the same as the non-interacting renormalization group approach but without the perturbation theory and found that for strong disorder this technique could accurately calculate the density of states over a wide range of energies but deviated from exact results at the band edge, at $\omega=\pm U$ and near $\omega=0$. The first two inaccuracies will be reduced with a proper real-space renormalization group approach. We suspect that the last inaccuracy is associated with long range physics and may be difficult to recover. We also developed a technique that adjusts the identification of clusters in the cluster approach to improve the computation time of the density of states with minimal loss of accuracy in a tunable range around the Fermi level. We found that this technique significantly reduced the computation time and was able to preserve the density of states near the Fermi level, except at the smallest energies near $\omega=0$. Author Keywords: Anderson-Hubbard model, renormalization group, Strong electron correlations, Zero-bias anomaly
Cloud Versus Bare Metal
A comparison of two high performance computing clusters running on AWS and Sharcnet was done to determine which scenarios yield the best performance. Algorithm complexity ranged from O (n) to O (n3). Data sizes ranged from 195 KB to 2 GB. The Sharcnet hardware consisted of Intel E5-2683 and Intel E7-4850 processors with memory sizes ranging from 256 GB to 3072 GB. On AWS, C4.8xlarge instances were used, which run on Intel Xeon E5-2666 processors with 60 GB per instance. AWS was able to launch jobs immediately regardless of job size. The only limiting factors on AWS were algorithm complexity and memory usage, suggesting a memory bottleneck. Sharcnet had the best performance but could be hampered by the job scheduler. In conclusion, Sharcnet is best used when the algorithm is complex and has high memory usage. AWS is best used when immediate processing is required. Author Keywords: AWS, cloud, HPC, parallelism, Sharcnet


Search Our Digital Collections


Enabled Filters

  • (-) ≠ Farell
  • (-) ≠ Doctor of Philosophy

Filter Results


1973 - 2033
Specify date range: Show
Format: 2023/12/04