Graduate Theses & Dissertations

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Role of Multiple Nights of Sleep in the Consolidation of an Engaging and Complex Motor Learning Task
The present study examined the role of multiple nights of sleep in the consolidation of a complex motor learning task. Participants were 24 Trent undergraduates, 12 in the learning group (Mage = 20.33, SD = 1.87, 10 female) and 12 in the control group (Mage = 21.92, SD = 3.42, 7 female). Participants underwent 5 consecutive nights of polysomnographic recordings, with a Rock Band learning session on the third night. A series of 2(group)x4(night) ANOVAs were performed on the sleep variables. Interactions were found in the number of spindles detected at Pz, F(333) = 9.19, p <.01, and in the density of spindles detected at Pz, F(3,33) = 4.06, p <.05. The pattern of changes from baseline was significantly different between the two groups; spindles increased in the learning group and decreased in the control group. The novel finding was that spindle number/density remained elevated at the third post-learning night of sleep. Author Keywords: Motor Learning, Procedural Memory, Sleep, Sleep Spindles
Role of Policy in Arctic Food (In)Security
Hunger is a significant concern in Canada, and even more so in the North, with 52% of Inuit adults in Arctic regions experiencing some level of food insecurity in 2012. Policy deficiencies are argued to, at the least, be partly responsible for this issue. This qualitative exploratory project aimed to answer the question: What is the role of food-related policy(ies) in household food security? A review and analysis of policy documents and academic literature at three jurisdictional levels, using the case of food insecurity in Nunavik, Québec, was conducted. The study identified 281 policies facilitating and 139 policies acting as barriers to food security. The highest proportion (27%) of facilitators related to economic accessibility of food and the highest proportion of barriers (93%) related to political accessibility of food. Only one previously identified factor influencing household food security in the region had a corresponding policy barrier associated with it. The study suggests that what is considered ‘food policy’ differs significantly between jurisdictions. Many of the same policies that act to facilitate some aspects of food security act as barriers to others. Policy barriers tend to be difficult to identify by their very nature. As a result, policy plays a complicated role in Nunavik food security status, representing a positive influence in some regards and a negative one in others. Author Keywords: Arctic, Food, Food security, Inuit, Nunavik, Policy
Rural Older Adult Transitions in Care
Aligning health services with aging populations is the fundamental issue of modern Canadian health policy, yet rural older populations still experience compromised patient safety and poor-quality care as they transfer between care settings. As such, contemporary scholars acknowledge that more contextually sensitive studies are needed to better understand the unique health and care experiences of this vulnerable population across the care continuum. Informed by inquiry in critical gerontology, health services and human geography, my dissertation attends to this gap in research by revealing the interplay between older adult health construction and the influence of multidimensional contexts on rural older adult transitions in care. Using a community-based approach, I conduct a case study on Haliburton County that encompasses three phases (e.g., a rural community inventory, go-alongs and semi-structured interviews) and focuses on two types of transitions in care (when an older adult is transferred from a hospital to a long-term care home and when an older adult is transferred from a hospital to a home in the community). In total, 19 patients, 24 informal supports, 51 front-line staff and five administrators/managers participated in my dissertation, resulting in 99 total participants being included in 19 go-alongs and 85 semi-structured interviews. My results indicate that multi-leveled facets of the rural care context continually attend to and hinder rural older adult health during transitions in care. In particular, sectored divisions, urban centrism, biomedicine and ageism inhibit rural care providers from leveraging their strengths to attend to the heterogeneity of rural older adult health and the nuances of rural care contexts. I then argue the need for macro health systems reform to embrace the relationality of rural older adult transitions in care and to capitalize on the strengths inherent in rural communities. To foster knowledge mobilization of my findings, I provide a foundation of information and recommendations for the community partners (Haliburton Highlands Health Services and Seniors Care Network) as well as questions to inform research, policy and practice. Establishing the first study of rural older adult transitions in care where a researcher accompanies older adults and their informal supports across care settings, my dissertation will help prepare Canada for the impact of the aging population and transform transitional care provision to meet the needs of all Canadians in the 21st century. Author Keywords: Canada, Geriatric Care, Health Care, Older Adult Health, Rural Health Care, Transitions in care
SARS-CoV-2 Protein-based Detection Using Localized Surface Plasmon Resonance
During the COVID-19 pandemic, nucleic acid and antibody-based testing methods were heavily relied upon, but can be costly, time-consuming and exhibit high false -negative and -positive rates. Thus, alternative strategies are needed. Viral antigens such as the SARS-CoV-2 spike (S) glycoprotein are critical in the function of the virus and useful as diagnostic biomarkers for viral infections. For biosensing applications, aptamers are suitable high-affinity and cost-effective binding partners for their specific targets. Using localized surface plasmon resonance (LSPR), real-time, rapid acquisition of results can be achieved, essential for improving the efficacy of a sensor. Herein, LSPR aptamer sensors were fabricated for the detection of the SARS-CoV-2 protein. Data indicate that the best performing aptasensor was the streptavidin-biotin sensor, while the current gold aptasensor exhibited lower sensitivity and the fabrication of the carboxyl aptasensor was unsuccessful. The S1 aptamer selectively bound the S1 protein with high binding affinity. Excellent shelf-life stability, reusability, and high recovery in complex matrices was also maintained. Additionally, a receptor binding domain (RBD) functionalized sensor was fabricated to examine the interactions with angiotensin converting enzyme 2 (ACE2), for future assessment of inhibitors used in drug therapies. Overall, LSPR has been demonstrated as a viable tool for measuring SARS-CoV-2 related aptamer-protein and protein-protein interactions, and this strategy may be applied to other viral or non-viral antigen targets. Author Keywords: Antigen-based Detection, Coronavirus, COVID-19, Inhibition, Localized Surface Plasmon Resonance, SARS-CoV-2
SPAF-network with Saturating Pretraining Neurons
In this work, various aspects of neural networks, pre-trained with denoising autoencoders (DAE) are explored. To saturate neurons more quickly for feature learning in DAE, an activation function that offers higher gradients is introduced. Moreover, the introduction of sparsity functions applied to the hidden layer representations is studied. More importantly, a technique that swaps the activation functions of fully trained DAE to logistic functions is studied, networks trained using this technique are reffered to as SPAF-networks. For evaluation, the popular MNIST dataset as well as all \(3\) sub-datasets of the Chars74k dataset are used for classification purposes. The SPAF-network is also analyzed for the features it learns with a logistic, ReLU and a custom activation function. Lastly future roadmap is proposed for enhancements to the SPAF-network. Author Keywords: Artificial Neural Network, AutoEncoder, Machine Learning, Neural Networks, SPAF network, Unsupervised Learning
SPATIAL AND TEMPORAL GENETIC STRUCTURE OF WOLVERINE POPULATIONS
Habitat loss and fragmentation can disrupt population connectivity, resulting in small, isolated populations and low genetic variability. Understanding connectivity patterns in space and time is critical in conservation and management planning, especially for wide-ranging species in northern latitudes where habitats are becoming increasingly fragmented. Wolverines (Gulo gulo) share similar life history traits observed in large-sized carnivores, and their low resiliency to disturbances limits wolverine persistence in modified or fragmented landscapes - making them a good indicator species for habitat connectivity. In this thesis, I used neutral microsatellite and mitochondrial DNA markers to investigate genetic connectivity patterns of wolverines for different temporal and spatial scales. Population genetic analyses of individuals from North America suggested wolverines west of James Bay in Canada are structured into two contemporary genetic clusters: an extant cluster at the eastern periphery of Manitoba and Ontario, and a northwestern core cluster. Haplotypic composition, however, suggested longstanding differences between the extant eastern periphery and northwestern core clusters. Phylogeographic analyses across the wolverine's Holarctic distribution supported a postglacial expansion from a glacial refugium near Beringia. Although Approximate Bayesian computations suggested a west-to-east stepping-stone divergence pattern across North America, a mismatch distribution indicated a historic bottleneck event approximately 400 generations ago likely influenced present-day patterns of haplotype distribution. I also used an individual-based genetic distance measure to identify landscape features potentially influencing pairwise genetic distances of wolverines in Manitoba and Ontario. Road density and mean spring snow cover were positively associated with genetic distances. Road density was associated with female genetic distance, while spring snow cover variance was associated with male genetic distance. My findings suggest that northward expanding anthropogenic disturbances have the potential to affect genetic connectivity. Overall, my findings suggest that (1) peripheral populations can harbour genetic variants not observed in core populations - increasing species genetic diversity; (2) historic bottlenecks can alter the genetic signature of glacial refugia, resulting in a disjunct distribution of unique genetic variants among contemporary populations; (3) increased temporal resolution of the individual-based genetic distance measure can help identify landscape features associated with genetic connectivity within a population, which may disrupt landscape connectivity. Author Keywords: conservation genetics, Holarctic species, landscape genetics, peripheral population, phylogeography, wolverine
Sacred Space, Ancestors, and Authority
The Middle Formative Period (1000 – 400 B.C.) has increasing become recognized as a critical locus in the development of Lowland Maya socio-political complexity. This period witnessed the founding of numerous ceremonial centers, substantial material cultural innovation, and the advent of mortuary practices indicating developing social differentiation. Recent excavations at the site of Ka’Kabish in Northern Belize have uncovered evidence significantly strengthening this view. Excavations underlying Plaza D-South at Ka’Kabish have revealed a series of bedrock-hewn pits containing offering caches of thousands of shell beads, forty-seven greenstone objects, and extensive ceramic evidence indicating communal ritual and feasting, which is argued by the author to represent a cosmographic diorama of the cave-riddled Underworld. Significantly, this elaborate cosmographic offering event appears to center on the secondary, bundled bedrock-cist burial of an important personage and/or ancestor who is accompanied by a number of finely crafted jade ornaments representing motifs and forms that have previously been interpreted as symbols of authority, rulership, and divine kingship. Comparable contemporary evidence from Northern Belize and beyond has been interpreted through models foregrounding site-founding, place-making, ancestor veneration, and aggrandizer driven social differentiation. By integrating and contrasting these existing models with new evidence from Ka’Kabish, this thesis argues that the mortuary, caching, and architectural practices evidenced at Middle Formative Ka’Kabish represent a glimpse into the incipience of the ideological complex, the socio-cultural processes, and the material manifestations propagating the development of subsequent Maya socio-political complexity, specifically the institution of divine kingship or ch’uhul ahau. Author Keywords: ancestor veneration, ancient Maya, greenstone cache, Ka’Kabish, Belize, Middle Formative, socio-political complexity
Scarring, sex assignment, and sex-specific sociality of Indo-Pacific humpback dolphins (Sousa chinensis) in the Pearl River Estuary and eastern Taiwan Strait
The Pearl River Estuary (PRE) and eastern Taiwan Strait (ETS) populations of Indo-Pacific humpback dolphins (Sousa chinensis) contain ~600 and 100 catalogued individuals, respectively. Population demography is important for conservation actions but few animals have been sexed by conventional methods. Longitudinal analysis of tooth-rake scars on dorsal fins showed scars disappear within 7 months; sexing adults by scarring is likely not impacted by juvenile scarring. Using dorsal fin photographs, sex assigned for 87% of catalogued PRE adults (n=300) and for 93% of ETS adults (n=60), using scars hypothesized from male-male competition, was in concordance with sex assigned by DNA, calf association, and ventral photographs. Scarring was higher in presumed males than females and in PRE females than ETS females. Female:male sex ratios were 3:2 (PRE) and 2:1 (ETS), though this likely results from biases in photo-identification methods. Social analysis with presumed sexes showed strong female-female associations in both populations but stronger female-male and male-male associations in PRE. These results support sex differentiation by scarring, which was a non-invasive approach, and sex assignment for many PRE and ETS individuals. Author Keywords: Indo-Pacific humpback dolphins, photo-identification, scarring, sex differentiation, sexes, social structure
Scientificity of Psychology and the Categorical Paradigm of Mental Illness
There is little research devoted to exploring psychology's historical and discursive development. Psychological knowledge is generally presented as the contributions of individuals, but without context. The social, political, and economic aspects of psychology's development are scarcely discussed, including how the discipline came to be considered a science. This thesis project explored the history of the development of psychology. Specifically, psychology's claim to scientificity via the appropriation of the medical model of disease, and accordingly, the instantiation of the categorical paradigm of mental illness were examined. The discontinuous events that shaped psychology and its hallmark of scientificity were explored, including extensive concept transformations, political agendas, and marketing strategies. These practices were then explored in a practical way using the conception of clinical depression and the role of antidepressants as the first-line treatment for depression in the USA. This exploration revealed psychology's socio-historical contingencies and its agenda of prediction and control. Author Keywords: Categorical Paradigm, Concept Transformations, Historicity, Knowledge Products, Psychology, Scientificity
Scripted Sexual Beliefs and Behaviours
Sexual script theory suggests that sexual behaviours have social meaning, and that individuals perceive certain behaviours as normative and expected. Previous research has indicated that there is a common belief in a cultural sexual script for (hetero)sexual behaviour sequences (CSSHS). Study 1 compared perceived norms with behaviours in first ever penile-vaginal intercourse (PVI) sex events, as well as first and recent events with most recent partners. Many participants reported the CSSHS as typical, but few reported personal experiences that followed the CSSHS. Script adherence was not strongly related to physical pleasure. Study 2 found that committed relationships predicted greater female pleasure in first ever PVI sex. This link was mediated by communication during sexual activity. Results are discussed in the context of sexual script theory. Findings suggest that common scripted assumptions regarding PVI sex events should be reviewed for their value and representation of norms. Author Keywords: female pleasure, first sexual experiences, penile-vaginal intercourse, perceived norms, sexual behaviours, sexual script theory
Seasonal habitat use and movement of native brook trout (Salvelinus fontinalis) in urban headwater streams
Coldwater streams are becoming increasingly impacted due to urbanization. Using environmental surveys, mark-recapture and telemetry, I assessed factors influencing seasonal brook trout (Salvelinus fontinalis) habitat use and movement in urban headwater streams in central Ontario between 2017-18. Generalized additive models were used to assess which habitat variables best explained seasonal yearling and older brook trout abundance, while generalized least squares models were used to assess overall trends in radio-tagged brook trout movement. My research demonstrated dynamic patterns in habitat use and movement by urban stream-dwelling brook trout. Yearlings were primarily influenced by water quality (stream temperature, conductivity), while older brook trout were most strongly influenced by stream morphology (depth, undercut bank). Movement occurred disproportionately around the spawning season and was more limited in the smaller, more altered stream. These findings may be used to inform fisheries managers on crucial timing and location of brook trout habitat refugia within urbanized environments. Author Keywords: Brook trout, coldwater stream, groundwater, habitat use, radiotelemetry, urbanization
Seasonal variation in nutrient and particulate inputs and outputs at an urban stormwater pond in Peterborough, Ontario
Stormwater ponds (SWPs) are a common feature in new urban developments where they are designed to minimize runoff peaks from impervious surfaces and retain particulate matter. As a consequence, SWPs can be efficient at retaining particle-bound nutrients, but may be less efficient at retaining nutrients that are present primarily in the dissolved form, like nitrogen (N). However, the forms of nutrients (e.g. particulate vs. dissolved) likely differ with hydrologic and seasonal conditions and few studies have examined year-round differences in nutrient forms and concentrations at urban SWPs. In order to contrast total suspended solids (TSS), phosphorus (P) and nitrogen (N) levels between low and high flow conditions, sampling was conducted at an urban SWP in Peterborough, ON between November 2012 and October 2013. Only an increase in TSS levels at the outflow between low and high flow conditions was observed, as well as a decrease in TSS levels at the outflow compared to Inflow 1 under low flow conditions. Nitrate-N (NO3-N) was the dominant form of N entering the pond under all flow conditions, whereas the fraction of total-P (TP) that was particulate increased under high flow conditions. Nevertheless, the dissolved fraction of TP was consistently high in these urban inlets. Only NO3-N was significantly greater in the inflows than outflow and only under low flow conditions. Increases in the proportions of organic-N and ammonium-N in the outlet suggest that biological processing is important for N retention. Author Keywords: nitrogen, Ontario, phosphorus, stormwater ponds, total suspended solids

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Graduate student theses produced at Trent University. You may also browse theses and dissertations by year, program, or author.

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1973 - 2033
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