Graduate Theses & Dissertations

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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
Proximal Soil Nutrient Sensing in Croplands through Multispectral Imaging from Unmanned Aerial Vehicles (UAV) for Precision Agriculture Applications
Currently, UAVs are deployed to measure crop health in a timely manner by mapping vegetation indices. A study using two different fields was conducted in order to search for a relationship that may exist between crop health and soil fertility. A UAV equipped with sensor technology was used for mapping of vegetation indices which were then statistically compared to soil nutrient data collected via soil sampling. Elevation data was also collected which was then statistically compared to soil nutrients as well as crop health. Results of this study were unfortunately impacted by variables outside of the researcher’s control. Moisture became the greatest limiting factor in 2016 followed by an excess of rain in 2017. Results did not show any promising correlations as moisture uncontrollably became the defining variable. Further research in a more controlled setting will need to be conducted in order to explore this potential relationship. Author Keywords: Agriculture, Multispectral Imagery, Precision Agriculture, Proximal Soil Sensing, Remote Sensing, Unmanned Aerial Vehicle
Comparison of the Optical Properties of Stratiotes aloids and the Local Plant Community
As part of a mandate to control the spread of Stratiotes aloides (WS; water soldier) in the Trent Severn Waterway, the Ministry of Natural Resources (MNR) created a management plan to eradicate WS. However, one of the biggest challenges in eradicating WS or any invasive aquatic plant is the ability to estimate the extent of its spread and detect new populations. While current detection methods can provide acceptable detection, these methods often require extensive time and effort. The purpose of this thesis was to assess the use optical properties of WS and WS exudates for detection, in order to improve on current detection methods. The optical properties of WS were sampled at three different sites during three different seasons (spring, summer, and fall) by a) randomly sampling tissue from WS and the local plant community at each site, and recording the reflectance properties in a laboratory setting b) collecting dissolved organic matter (DOM) samples from plant incubations and river water in the field. Significant differences in the reflectance properties of WS were observed among samples from different sites and different sampling times; however, changes in fluorescence properties were only seasonal. Despite spatial differences in WS reflectance; WS was detectable using both hyperspectral and multispectral reflectance. When hyperspectral reflectance was used, significant differences between WS and the local plant community were found in June using two bands (i.e. bands 525 and 535, R 2 = 0.46 and 0.48, respectively). Whereas multispectral reflectance was significant different in October using the coastal and blue band. While WS produced a unique signal using both reflectance types, multispectral reflectance had a greater potential for detection. Its greater potential for detection was due to the reduced noise produced by background optical properties in October in comparison to June. DOM derived from WS was also characterized and compared with whole-river DOM samples in order to find unique markers for WS exudates in river samples. While similarities in DOM concentrations of WS exudates to Trent River water limited the ability to detect WS using compositional data, the ratio of C4/C5 components were compared in order to find components that were proportionally similar. Based on the results of this study multispectral and fluorescence techniques are better suited for the detection of a unique WS signature. The results derived from this work are intended to have practical applications in plant management and monitoring, DOM tracing, as well as remote sensing. Author Keywords: Dissolved organic matter, Hyperspectral reflectance, Invasive species management, Multispectral reflectance, PARAFAC, Stratiotes aloides
Fish and invertebrate use of invasive Phragmites in a Great Lakes freshwater delta
Invasive Phragmites australis ssp. australis (herein “Phragmites”) has established and rapidly spread throughout many coastal areas of the Great Lakes. Known to displace native vegetation communities as it forms large, monotypic stands, Phragmites has a bad reputation when it comes to losses of biodiversity and habitat provision for wildlife. However, the extent to which Phragmites provides habitat for fish and invertebrates in coastal freshwater wetlands remains relatively unquantified. Thus, this study assessed whether fish assemblages and invertebrate communities in stands of Phragmites differ from those in stands of two native emergent vegetation communities, Typha spp. and Schoenoplectus spp. The findings showed significant differences in habitat variables among the vegetation communities in terms of water depth, macrophyte species richness, stem density and water quality. While abundance of the functional feeding group filterer-collectors was found to be significantly less in stands of Phragmites when compared to Schoenoplectus, no difference was observed in invertebrate taxa richness among vegetation communities. Lastly, no difference in fish assemblage or invertebrate community was detected when using multivariate analyses, implying that invasive Phragmites provides habitat that appears to be as valuable for fish and invertebrates as other emergent vegetation types in the St. Clair River Delta. The findings of this study will ultimately benefit the literature on invasive Phragmites and its role as fish habitat in freshwater wetlands, and aid management agencies in decisions regarding control of the invasive species. Author Keywords: aquatic invasive species, aquatic macroinvertebrates, freshwater fish, freshwater wetlands, nMDS, Phragmites
Developing a Sustainable Resort
Sustainability-related issues have been drawing considerable attention in the resort and hotel industry. This research explores the meaning of a “sustainable resort” and to identify the opportunities and challenges of developing a “sustainable resort” as well as the opportunities and challenges of engaging employees in this process, through a case study of a family resort in Central Ontario, Canada. A significant finding is that a “sustainable resort” in the context of a family business highlights cultural sustainability, which emphasizes on keeping family roots and passing on family legacy, as well as addresses economic, social, and environmental sustainability. The nature of the selected case, a traditional family resort, provides some valuable insights on the issues of sustainability and employee engagement in the resort and hotel industry. To improve sustainable outcomes for the resort, a holistic approach of collaborating with different key stakeholders, particularly emphasizing employee engagement as a core strategy, is proposed. Author Keywords: employee engagement, family resort, resort and hotel industry, sustainability, sustainable development
Application of One-factor Models for Prices of Crops and Option Pricing Process
This thesis is intended to support dependent-on-crops farmers to hedge the price risks of their crops. Firstly, we applied one-factor model, which incorporated a deterministic function and a stochastic process, to predict the future prices of crops (soybean). A discrete form was employed for one-month-ahead prediction. For general prediction, de-trending and de-cyclicality were used to remove the deterministic function. Three candidate stochastic differential equations (SDEs) were chosen to simulate the stochastic process; they are mean-reverting Ornstein-Uhlenbeck (OU) process, OU process with zero mean, and Brownian motion with a drift. Least squares methods and maximum likelihood were used to estimate the parameters. Results indicated that one-factor model worked well for soybean prices. Meanwhile, we provided a two-factor model as an alternative model and it also performed well in this case. In the second main part, a zero-cost option package was introduced and we theoretically analyzed the process of hedging. In the last part, option premiums obtained based on one-factor model could be compared to those obtained from Black-Scholes model, thus we could see the differences and similarities which suggested that the deterministic function especially the cyclicality played an essential role for the soybean price, thus the one-factor model in this case was more suitable than Black-Scholes model for the underlying asset. Author Keywords: Brownian motion, Least Squares Method, Maximum Likelihood Method, One-factor Model, Option Pricing, Ornstein-Uhlenbeck Process
Building Individuals, Building the Economy
This thesis explores the neoliberal governmentality approach to education for Northern economic development that was prevalent from 2006 to 2015, during Stephen Harper’s period as Prime Minister of Canada. Using a grounded theory approach, this thesis identifies three themes – Indigenous integration, education, and employment for labour force/ economic development – to direct an analysis on programs and funding supported by the Canadian Northern Economic Development Agency, Employment and Social Development Canada, and Indigenous and Northern Affairs Canada. This examination suggests that Federal programming and funding encouraged neoliberal governmentality approaches to Northern development and education. Specifically, the former Government interest in developing an Indigenous work force to serve labour market needs is brought to light. Author Keywords: Economic Development, Indigenous Education, Labour Force Development, Neoliberalism, Territorial North
Electrochemical Characterization of Giardia Intestinalis Cytochromes b5
Giardia intestinalis is a protozoan parasite that causes waterborne diarrheal disease in animals and humans. It is an unusual eukaryote as it lacks the capacity for heme biosynthesis; nonetheless it encodes heme proteins, including three cytochrome b5 isotypes (gCYTB5s) of similar size. Homology modelling of their structures predicts increased heme pocket polarity compared to mammalian isotypes, which would favour the oxidized state and lower their reduction potentials (E°’). This was confirmed by spectroelectrochemical experiments, which measured E°’ of -171 mV, -140 mV and -157 mV for gCYTB5-I, II, III respectively, compared to +7 mV for bovine microsomal cytochrome b5. To explore the influence of heme pocket polarity in more detail, five gCYTB5-I mutants in which polar residues were replaced by nonpolar residues at one of three positions were investigated. While these substitutions all increased the reduction potential, replacement of a conserved tyrosine residue at position-61 with phenylalanine had the most significant effect, raising E°’ by 106 mV. This tyrosine residue occurs in all gCYTB5s and is likely the greatest contributor to their low reduction potentials. Finally, complementary substitutions were made into a bovine microsomal cytochrome b5 triple mutant to lower its reduction potential. These not only lowered the E°’ by more than 140 mV but also weakened the interaction of heme with the protein. The lower reduction potentials of the gCYTB5s may indicate that these proteins have different roles from their more well-known mammalian counterparts. Author Keywords:
Mfsd8 regulates growth and multicellular development in Dictyostelium discoideum
The neuronal ceroid lipofuscinoses (NCLs), commonly known as Batten disease, are a family of inherited neurodegenerative lysosomal storage disorders. CLN7 disease is a subtype of NCL that is caused by mutations in the MFSD8 gene. MFSD8 encodes a lysosomal transmembrane protein that is predicted to play a role in transporting small substrates across membranes. However, little is known about its role and substrate specificity. Previous work identified an ortholog of human MFSD8 in the social amoeba Dictyostelium discoideum and reported its localization to endocytic compartments. In this study, the effects of mfsd8 loss during Dictyostelium growth and multicellular development were further characterized. Dictyostelium mfsd8- cells displayed increased rates of proliferation and pinocytosis in liquid media. During growth, loss of mfsd8 altered lysosomal enzymatic activities and reduced the intracellular and extracellular levels of autocrine proliferation repressor A. mfsd8- cells grown on a lawn of bacteria formed plaques in a shorter period of time compared to WT cells, providing additional support for the enhanced growth of mfsd8- cells. Upon starvation, the aggregation of mfsd8- cells was delayed, and mfsd8- cells formed more mounds that were smaller in size, which may be attributed to the reduced cell-substrate adhesion and altered lysosomal enzymatic activities observed for mfsd8- cells. Following aggregation, tipped mound formation was delayed, however, loss of mfsd8 did not affect the timing of slug/finger and fruiting body formation. Additionally, slug migration was reduced in mfsd8- cells. These aberrant phenotypes, excluding fruiting body formation, were effectively or partially rescued when Mfsd8-GFP was introduced into mfsd8- cells. Overall, these results show that Mfsd8 plays a role in regulating growth and developmental processes in Dictyostelium via lysosomal-associated functions. Author Keywords: CLN7, Dictyostelium discoideum, Lysosomes, MFSD8, Neuronal Ceroid Lipofuscinoses
Ecological and morphological traits that affect the fitness and dispersal potential of Iberian pumpkinseed (Lepomis gibbosus)
The Pumpkinseed (Lepomis gibbosus) is a sunfish that is endemic to eastern portions of Canada and the United States. During the late 19th century, the species was introduced into Europe, and it is now present in over 28 countries. Previous attempts to determine the characteristics that can predict the spread of non-indigenous species have been largely unsuccessful, but new evidence suggests that phenotypic plasticity may help to explain the dispersal and range expansion of some organisms. Experimental comparisons on lower-order taxa have revealed that populations from areas outside of their native range are capable of exhibiting stronger levels of phenotypic plasticity than counterparts from their source of origin. Using Pumpkinseed, I conducted the first native/non- native comparison of phenotypic plasticity in a vertebrate. Progeny from adult Pumpkinseed collected in Ontario, Canada and the Iberian Peninsula (Spain) were reared under variable water velocities, habitat type and competitive pressures, three ecological factors that may affect the dispersal potential of fishes introduced into novel aquatic systems. Differences in phenotypic plasticity, assessed from a morphological perspective, were compared among populations using a traditional distance-based approach. All populations exhibited divergent morphological traits that appeared to be inherited over successive generations. In each experiment, all populations responded to environmental change by developing internal and external morphological forms that, in related taxa, enhance and facilitate foraging and navigation; however, non-native populations always exhibited an overall lower level of phenotypic plasticity. Pumpkinseed from non-native areas may have exhibited a reduction in phenotypic plasticity because of population-based differences. Nevertheless, all Pumpkinseed populations studied were capable of exhibiting phenotypic plasticity to novel environmental conditions, and develop morphological characteristics that may enhance fitness and dispersal in perturbed areas. Author Keywords: Invasive species, Morphology, Phenotypic plasticity, Pumpkinseed sunfish, Reaction norm
evolutionary ecology of Alaska's mountain goats with management implications
The integration of genetic and environmental information can help wildlife managers better understand the factors affecting a species’ population structure and their response to disturbance. This thesis uses genetic techniques to assess the broad and fine scale population structure of mountain goats in Alaska. The first chapter aims to determine the number of genetically distinct subpopulations and model the demographic history of mountain goats in Alaska. The second chapter investigates the population structure and demographic history of mountain goats in Glacier Bay National Park and examines the impact that climate change will have on these mountain goats. My results indicate that Alaska has eight subpopulations which diverged during the Wisconsin glaciation. In Glacier Bay, population structure is reflective of the landscape during colonization, and mountain goat population density and movement corridors are likely to decline due to future climate change. Author Keywords: Alaska, biogeography, gene flow, landscape genetics, mountain goat, population genetic structure
Virtual Voices
A consistent provincial approach to capacity planning for rehabilitative care had been identified as a critical gap in the field of health care in Ontario (Rehabilitative Care Alliance, 2015a). In response, the rehabilitative care alliance (RCA) developed a needs based hip fracture capacity planning canvas together with persons and families. This research utilized computer assisted participation (CAP) to gather additional perspectives from Virtual Voices via an on-line survey. The results of the Virtual Voices survey were compared to Ontario’s RCA hip fracture patient focus group findings. CAP facilitated more voices and more ideas through virtual engagement. The survey method required 97% (10.6 hours) less time than the focus group. The Virtual Voices respondents provided validation of the focus groups’ confirmation of the rehabilitative care needs, locations and most core team members as well as identified new ideas. The results support the implementation of a needs-based capacity plan that enables individualized care planning. This research provides a blueprint for the ongoing engagement of persons and families in the co-creation of a sustainable rehabilitative care system. A dashboard and e-health app would enable ongoing co-design, monitoring and evaluation. Author Keywords: Computer Assisted Participation (CAP), Computer Assisted Survey, Hip Fracture, Rehabilitative Care Needs, Virtual Collaboration, Virtual Engagement

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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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