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Comparative phylogeography in conservation biology: unravelling the evolutionary histories of disjunct and invasive species around the Laurentian Great Lakes

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Creator (cre): Ciotir, Claudia Elena, Thesis advisor (ths): Freeland, Joanna, Degree committee member (dgc): Dorken, Marcel, Degree committee member (dgc): Wilson, Christopher, Degree granting institution (dgg): Trent University
Abstract:

Phylogeographic histories of taxa around the Great Lakes region in North America are relevant to a range of ongoing issues including conservation management and biological invasions. In this thesis I investigated the comparative phylogeographic histories of plant species with disjunct distributions and plant species with continuous distributions around the Great Lakes region; this is a very dynamic geographic area with relatively recent colonisation histories that have been influenced by a range of factors including postglacial landscape modifications, and more recently, human-mediated dispersion. I first characterized four species that have disjunct populations in the Great Lakes region: (Bartonia paniculata subsp. paniculata, Empetrum nigrum, Sporobolus heterolepis, and Carex richardsonii). Through comparisons of core and disjunct populations, I found that a range of historical processes have resulted in two broad scenarios: in the first scenario, genetically distinct disjunct and core populations diverged prior to the last glacial cycle, and in the second scenario more recent vicariant events have resulted in genetically similar core and disjunct populations. The former scenario has important implications for conservation management. I then characterized the Typha species complex (T. latifolia, T. angustifolia, T. x glauca), which collectively represent species with continuous distributions. Recent microevolutionary processes, including hybridization, introgression, and intercontinental dispersal, obscure the phylogeographic patterns and complicate the evolutionary history of Typha spp. around the Great Lakes region, and have resulted in the growing dominance of non-native lineages. A broader geographical comparison of Typha spp. lineages from around the world identified repeated cryptic dispersal and long-distant movement as important phylogeographic influences. This research has demonstrated that comparisons of regional and global evolutionary histories can provide insight into historical and contemporary processes useful for management decisions in conservation biology and invasive species.

Author Keywords: chloroplast DNA, conservation genetics, disjunct populations, invasive species, phylogeography, postglacial recolonisation

2015

Utilizing Class-Specific Thresholds Discovered by Outlier Detection

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Creator (cre): Branch, Richard Arthur Conan, Thesis advisor (ths): McConnell, Sabine, Thesis advisor (ths): Hurley, Richard, Degree granting institution (dgg): Trent University
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We investigated if the performance of selected supervised machine-learning techniques could be improved by combining univariate outlier-detection techniques and machine-learning methods. We developed a framework to discover class-specific thresholds in class probability estimates using univariate outlier detection and proposed two novel techniques to utilize these class-specific thresholds. These proposed techniques were applied to various data sets and the results were evaluated. Our experimental results suggest that some of our techniques may improve recall in the base learner. Additional results suggest that one technique may produce higher accuracy and precision than AdaBoost.M1, while another may produce higher recall. Finally, our results suggest that we can achieve higher accuracy, precision, or recall when AdaBoost.M1 fails to produce higher metric values than the base learner.

Author Keywords: AdaBoost, Boosting, Classification, Class-Specific Thresholds, Machine Learning, Outliers

2016

Reassessing Bioarchaeological Sex Determination and Research into Gender at the Early Anglo-Saxon Worthy Park Burial Ground Round in Hampshire, England

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Creator (cre): Downer, Abigail Clarissa, Thesis advisor (ths): Williams, Jocelyn S, Degree committee member (dgc): Munson, Marit K, Degree committee member (dgc): Keenleyside, Anne, Degree granting institution (dgg): Trent University
Abstract:

When bioarchaeologists investigate ancient gender identity, they typically place skeletal remains into one of six sex assessment categories: male, female, possible/probable male, possible/probable female, ambiguous, and indeterminate. However, the study samples are often reduced to male and female reproducing a male/female gender and sex binary prevalent in the "Western" cultural milieu and bioarchaeology when inferences are made about gender and sex in the past.

In order to allow for the existence of non-binary cultural genders and biological sexes, this thesis: 1) demonstrates the multitude of ethnographic, ethnohistoric, historic, and medical evidence relating to non-binary sex and gender expression; 2) tests a method inspired by Whelan (1991) that looks at gender as an identity not fully inspired by biological sex; 3) keeps all sex assessment categories used by bioarchaeologists separate in analysis and interpretation; and 4) analyses patterns relating to all available material culture and biological attributes in a mortuary sample to investigate gender identity.

This thesis used the Early Anglo-Saxon (470-600 AD) burial ground at Worthy Park in Hampshire to achieve these objectives. This thesis found that when examining all sex assessment categories among all mortuary variables, only the male sex was clearly defined by its mortuary assemblage. This suggests a one gender structure corresponding to linguistic evidence for one gender in Old English.

Author Keywords: Anglo-Saxon, Bioarchaeology, Gender identity, Mortuary archaeology, Osteoarchaeology, Sex determination

2015

Detecting anti-estrogens and anti-androgens in surface waters impacted by municipal wastewater discharges and agricultural runoff

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Creator (cre): Corcoran, Shawna Karen Jackson, Thesis advisor (ths): Metcalfe, Chris, Degree committee member (dgc): Ellis, David, Degree committee member (dgc): Gueguen, Celine, Degree granting institution (dgg): Trent University
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This study focused on detecting 22 target anti-estrogenic and anti-androgenic compounds in surface waters influenced by both discharges of municipal wastewater and agricultural runoff in Canada and Argentina. Polar organic chemical integrative samplers (POCIS) were used to monitor the target compounds in surface waters. The removals of the target compounds in a municipal wastewater treatment plant (WWTP) in Canada were also evaluated. In both Canada and Argentina pesticides with potential anti-estrogenic and anti-androgenic activities were detected in the surface waters. The highest concentrations were found in Argentina (up to 1010 ng L-1) in areas impacted by heavy agricultural practices. Cyproterone acetate and bicalutamide were the only two anti-cancer drugs detected only at the Canadian study site, the Speed River, ON. In the Guelph WWTP, that discharges into the Speed River, these target compounds were not all efficiently removed (>70%) during treatment. Overall, this study provides insight to possible anti-estrogenic and anti-androgenic compounds that may be contributing to endocrine disrupting activities in surface waters.

Author Keywords: Anti-androgens, Anti-estrogens, Cancer Therapy Drugs, Current use pesticides, Pharmaceuticals and Personal Care Products, Polar Organic Chemical Integrative Samplers

2017

Evaulating the American Woodcock Singing-Ground Survey Protocol in Ontario using Acoustic Monitoring Devices

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Creator (cre): Walker, Jacob, Thesis advisor (ths): Nol, Erica, Thesis advisor (ths): Abraham, Kenneth F, Degree committee member (dgc): Nocera, Joseph J, Degree granting institution (dgg): Trent University
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The breeding phenology of American Woodcocks (Scolopax minor) was evaluated in Ontario, Canada to determine if changes in dates of courtship activity have introduced negative bias into the American Woodcock Singing-ground Survey (SGS). Long-term woodcock phenology and climate data for Ontario were analysed using linear regression to determine if woodcock breeding phenology has changed between 1968 and 2014. There was no significant trend in woodcock arrival date, but arrival date was correlated with mean high temperature in March. In 2011-2013, programmable audio-recording devices (song meters) were deployed at known woodcock singing-grounds to determine if peaks in courtship activity coincided with survey dates used by the SGS. Spectrogram interpretation of recordings and data analyses using mixed-effects models indicated the SGS survey dates were still appropriate, except during the exceptionally early spring in 2012 when courtship displays were waning in one region during the survey window. The methods for interpretation of song meter recordings were validated by conducting point counts adjacent to song meters deployed at singing-grounds, and at randomly selected locations in woodcock habitat. Recommendations for the SGS protocol are included.

Author Keywords: detectability, phenology, Scolopax minor, Singing-ground Survey, song meter

2015

Responses of Primary Producers and Grazers to Silver Nanoparticle Exposure

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Creator (cre): Vincent, Jennifer Lynn, Thesis advisor (ths): Xenopoulos, Marguerite A, Degree committee member (dgc): Hintelmann, Holger, Degree committee member (dgc): Schaefer, James A, Degree granting institution (dgg): Trent University
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The increasing production and use of silver nanoparticles (AgNPs) raise concerns on environmental exposure and impact. A large scale in situ enclosure study was conducted at the Experimental Lakes Area to determine the effect of AgNPs on natural phytoplankton and zooplankton communities. This study investigated AgNPs of varying concentrations (4, 16 and 64 μg/L), dosing regimens (chronic vs. pulse), and capping agents (poly-vinyl pyrrolidone vs. citrate). Phytoplankton communities were influenced only by the natural limnological properties of the system signifying tolerance to AgNPs. Zooplankton community structure significantly changed with AgNP concentration and dosing regimen indicating AgNP sensitivity. A microcosm study investigating the effect of AgNPs and phosphorus-dosed periphyton before and after grazing by two benthic invertebrate species (snails and caddisfly larvae) showed reduced periphyton stoichiometry with AgNP exposure. Grazers foraged less on silver dosed periphyton indicating a preferential choice in food quality. Phosphorus reduced the detrimental effects of AgNPs across all conditions. These studies verify the need for in situ experimental designs to fully investigate the effects of AgNPs and their interaction with environmental factors, multiple species assemblages, and across trophic levels.

Author Keywords: benthic invertebrate, Experimental Lakes Area, periphyton, phytoplankton, silver nanoparticles, zooplankton

2015

Investigation of Using Phase Change Materials for Thermal Energy Storage in Adiabatic Compressed Air Energy Storage

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Creator (cre): Tessier, Michael, Thesis advisor (ths): NARINE, SURESH S, Degree committee member (dgc): Atkinson, Bill A, Degree committee member (dgc): Kaye, Matthew H, Degree granting institution (dgg): Trent University
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There is an increasing global need for grid scale electrical energy storage to handle the implementation of intermittent renewable energy sources. Adiabatic compressed air energy storage is an emerging technology with similar performance to pumped hydro except it has the issue of heat loss during the compression stage. Previously, it has been considered to use sensible heat storage materials to store the heat created by compression in a thermal energy storage unit until energy is required, and then transfer the heat back to the air. This research proposes to instead use phase change materials to store the heat of compression, as this will reduce entropy generation and maximize roundtrip exergy efficiency. Different configurations and placements of the phase change materials are considered and exergy analyses are presented. The thermodynamic equations are derived and optimal setup conditions including amount of latent heat and melting temperatures are calculated.

Author Keywords: Compressed Air Energy Storage, Energy Storage, Exergy, Phase Change Materials

2015

Flavohemoglobin expression in Giardia intestinalis exposed to nitrosative stress

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Creator (cre): Teghtmeyer, Megan R, Thesis advisor (ths): Rafferty, Steven, Degree committee member (dgc): Brunetti, Craig, Degree committee member (dgc): Yee, Janet, Degree granting institution (dgg): Trent University
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The parasitic protist Giardia intestinalis lacks most heme proteins yet encodes a flavohemoglobin (gFlHb) that converts nitric oxide to nitrate and likely protects the cell from nitrosative stress. In this work an antibody raised against gFlHb was used to examine both changes in gFlHb expression levels and intracellular localization in Giardia in response to nitrosative stress. Giardia trophozoites exposed to stressors which either directly release nitric oxide (diethyltriamine NONOate, 1 mM) or are sources of other reactive nitrogen intermediates (sodium nitrite 20 mM or S-nitrosoglutathione, 1 or 5 mM) exhibited a 2 to 9-fold increase of gFlHb after 24 hours. Increased expression levels of gFlHb were detectable by 8 hours in S-nitrosoglutathione and diethyltriamine-NONOate-treated trophozoites, and by 12 hours after sodium nitrite exposure; these differences were likely due to differences in the rates of release of RNS from these compounds. In addition to a band of the expected size for gFlHb (52 kDa), western blots detected a second, higher molecular weight band (72 kDa) with comparable or higher intensity upon treatment with these RNS donors, which is consistent with sumoylation of gFlHb. Immunofluorescence microscopy of Giardia trophozoites detected gFlHb diffused throughout the cytoplasm and more punctuated staining along the cell membrane and between the nuclei. The punctuated staining may be due to the association of gFlHb with either peripheral vacuoles or basal bodies.

Author Keywords: Flavohemoglobin, Giardia intestinalis, Nitrosative stress

2017

Understanding the establishment of Typha spp. in North America using population genetics and common garden studies

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Creator (cre): Szabo, Jessica Lynn, Thesis advisor (ths): Freeland, Joanna R, Thesis advisor (ths): Doreen, Marcel E, Degree committee member (dgc): Wilson, Paul J, Degree granting institution (dgg): Trent University
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There are three cattail (Typha) taxa in Canada: T. latifolia (native), T. angustifolia (introduced), and their hybrid T. x glauca. The latter is invasive in regions around the Laurentian Great Lakes, and I investigated the potential role that commercial suppliers may be playing in the introduction of non-native Typha by comparing genotypes of North American, European, and commercially available plants. I found that Ontario garden centres are importing both hybrids and non-native lineages of T. angustifolia into Canada, but was unable to identify the provenance of T. latifolia. I also investigated the possibility that the hybrid cattail leaf litter shade and leachate influences germination and early growth of the parental species of the hybrids. Using three common garden experiments, I found that T. x glauca leaf litter suppresses germination rates of the three taxa. In the early seedling growth experiment, plant performance varied by taxa, and for the competition experiment there were no intra- or interspecific competition or treatment effects on the performance of plants. Overall, my research identified a potential mechanism allowing T. x glauca to dominate wetlands, and also shows that non-native lineages are being introduced into Canada through commercial trade

Author Keywords: Competition, Germination, Non-native lineages, Plant nurseries, Seedling Growth, Typha spp.

2016

Alpha and Omega: Interpretive Strategies and Freedom of Choice in Fallout 3

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Creator (cre): Morton, Robert Travis, Thesis advisor (ths): Mitchell, Liam, Degree committee member (dgc): Hodges, Hugh, Degree committee member (dgc): Epp, Michael, Degree granting institution (dgg): Trent University
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Game texts present unique and dynamic opportunities for lability: how readers can make choices while reading that alter the narrative's nature or outcome. Labile decisions are neither simply correct nor incorrect--the reader renders judgement to produce a desired outcome. When encountering labile challenges, players employ an interpretive strategy to resolve them. Many game texts tell stories. Games anticipate readers' interpretive strategies to orchestrate a desired result in labile narratives and manipulate players into inhabiting an identity in a variety of different ways. This thesis examines how Fallout 3 does so with periodically opposable intentions, mainly applying an inconsistent moral orthodoxy via the player character's father, but occasionally exhibiting the series' nihilistic philosophy that disdains American exceptionalism, undermining the orthodoxy. This isolates and breaks down the interpretive communities the player inhabits to play the game.

Author Keywords: Exceptionalism, Identity, Lability, Morality, Narrative, Video Games

2015