Graduate Theses & Dissertations

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Models of partitioning, uptake, and toxicity of neutral organic chemicals in fish
Models of partitioning, uptake, and toxicity of neutral organic chemicals in fish Alena Kathryn Davidson Celsie A novel dynamic fugacity model is developed that simulates the uptake of chemicals in fish by respiration as applies in aquatic toxicity tests. A physiologically based toxicokinetic model was developed which calculates the time-course of chemical distribution in four tissue compartments in fish, including metabolic biotransformation in the liver. Toxic endpoints are defined by fugacity reaching a 50% mortality value. The model is tested against empirical data for the uptake of pentachloroethane in rainbow trout and from naphthalene and trichlorobenzene in fathead minnows. The model was able to predict bioconcentration and toxicity within a factor of 2 of empirical data. The sensitivity to partition coefficients of computed whole-body concentration was also investigated. In addition to this model development three methods for predicting partition coefficients were evaluated: lipid-fraction, COSMOtherm estimation, and using Abraham parameters. The lipid fraction method produced accurate tissue-water partitioning values consistently for all tissues tested and is recommended for estimating these values. Results also suggest that quantum chemical methods hold promise for predicting the aquatic toxicity of chemicals based only on molecular structure. Author Keywords: COSMOtherm, fish model, fugacity, Partition coefficient, tissue-water, toxicokinetics
Canadian Refugee Policy
This dissertation is an inquiry into the politics of the frame in Canadian refugee policy. It is focused on "framing," thereby taking up the stance of critical policy studies while pressing the contribution of Donald Schön and Martin Rein in a critical and politically inflected direction. The dissertation unfolds as a political history of Canadian refugee policy that provides a "contextual mapping," relevant to both inquiry and action in regard to the framing of refugees. The main argument is that twentieth- and twenty-first- century refugee policy in Canada is a story of three shifting meta-frames: beginning with humanitarianism (in the inter-War years and the post-World War II period); shifting to neo-humanitarianism (beginning in the late 1970s, in connection with the rise of neoliberalism); then shifting again (beginning in the 1990s) to securitization. The concept of a meta-frame here is analogous to that of a "metacultural frame" in Schön and Rein, but accents political rather than cultural dimensions. This concept is developed in a manner suitable to a political history by illustrating how meta-frames both become stable and change. With humanitarianism, the refugee was typically portrayed in ambivalent terms - both deserving of and entitled to protection, while also posing a burden for the national interest. In the context of neo-humanitarianism, this ambivalence began to wane, and the refugee was more typically portrayed as a potential criminal. With securitization, especially as it has become entrenched and intensified, the refugee has been more typically portrayed as a potential terrorist. The analysis includes a focus on the particular importance of ambivalence and contingency in the politics of the frame. Securitization has become so deeply entrenched since September 11, 2001 that it appears virtually fixed in place. However, it may still become possible in moments of contingency for refugee advocates to destabilize the securitization meta-frame and help shift the framing of refugees into a more hospitable register. Author Keywords: ambivalence, contingency, humanitarianism, neo-humanitarianism, refugees, securitization
Absorbance and Fluorescence Characteristics of Dissolved Organic Matter in North Atlantic, Pacific and Arctic Oceans
This thesis was designed to quantify absorbance and fluorescence characteristics of dissolved organic matter (DOM) in North Atlantic, Pacific and Arctic Oceans. DOM was described in water masses of distinct sources and formation pathways as well as in regions where environmental forcings such as deep water upwelling, enhanced biological activity and receipt of freshwater discharge were prevalent. Influence of sea ice on DOM in Beaufort Sea mixed layer (0 to 30 m) seawater was investigated based on sea ice extent as well as freshwater fractions of meteoric (fmw) and sea ice melt water (fsim) calculated from oxygen isotope ratio (δ18O). The effect of DOM exposure to simulated solar radiation was also assessed to determine the resilience of fluorescent fractions of DOM to photodegradation. This research aims to further our ability to trace DOM in marine environments and better understand its transformation pathways and predict its fate as part of the oceanic carbon cycle in a changing climate. Author Keywords: Absorbance, Arctic Ocean, Dissolved organic matter, Fluorescence, Parallel Factor Analysis, Sea Ice
EVALUATION OF HAYFIELD MANAGEMENT STRATEGIES AND BOBOLINK TERRITORIAL HABITAT IN SOUTHERN ONTARIO
I implemented three hayfield management regimens in southern Ontario (a typical schedule at the farmer`s discretion, a delayed first harvest after July 14, and an early first harvest before June 1 with 65 days before second harvest), and evaluated the costs/benefits to farmers regarding hay quality and feasibility, and to Bobolinks (Dolichonyx oryzivorus) regarding reproductive activity and phenology. Typical management resulted in little to no Bobolink reproductive success, and early harvested sites were not (re)colonized. On delayed harvest sites Bobolinks experienced high reproductive success, but hay quality fell below ideal protein levels for most cattle before harvest. I also examined the habitat features Bobolinks use as the basis for establishing territories and associations between Bobolink territory size and habitat quality. I compared vegetation structure, patch size, and prey abundance between small and large territories. Small territories typically occurred on smaller fields with more preferred vegetation characteristics and greater prey abundance. Author Keywords: agro-ecosystem, Bobolink, Dolichonyx oryzivorus, grassland birds, hayfield management
An Investigation of the Impact of Big Data on Bioinformatics Software
As the generation of genetic data accelerates, Big Data has an increasing impact on the way bioinformatics software is used. The experiments become larger and more complex than originally envisioned by software designers. One way to deal with this problem is to use parallel computing. Using the program Structure as a case study, we investigate ways in which to counteract the challenges created by the growing datasets. We propose an OpenMP and an OpenMP-MPI hybrid parallelization of the MCMC steps, and analyse the performance in various scenarios. The results indicate that the parallelizations produce significant speedups over the serial version in all scenarios tested. This allows for using the available hardware more efficiently, by adapting the program to the parallel architecture. This is important because not only does it reduce the time required to perform existing analyses, but it also opens the door to new analyses, which were previously impractical. Author Keywords: Big Data, HPC, MCMC, parallelization, speedup, Structure
Genome annotation, gene characterization, and the functional analysis of natural antisense transcripts in the fungal plant pathogen Ustilago maydis
Ustilago maydis (DC) Corda is the causal agent of 'common smut of corn'. Completion of the U. maydis lifecycle is dependent on development inside its host, Zea mays. Symptoms of U. maydis infection include chlorosis and the formation of tumours on all aerial corn tissues. Within the tumours, thick-walled diploid teliospores form; these are the reproductive and dispersal agent for the fungus. U. maydis is the model to study basidiomycete biotrophic plant-pathogen interactions. It holds this status in part because of the completely sequenced 20.5 Mb genome; however, thorough genome annotation is required to fully realize the value of this resource. The research presented here improved U. maydis genome annotation through the analysis of cDNA library sequences and comparative genomics. These analyses identified and characterized pathogenesis-related genes, and identified putative meiosis genes. This enabled the use of U. maydis as a model for investigating 'host-induced' meiosis. Further, the cDNA library analyses identified non-coding RNAs (ncRNAs) and natural antisense transcripts (NATs). NATs are endogenous RNA molecules with regions complementary to a protein-coding transcript. Although NATs have been identified in a wide variety of mammals, plants, and fungi, very few have been functionally characterized. Over 200 U. maydis NATs were annotated by analyzing full-length cDNA sequences. NAT structural features were characterized. Strand-specific RT-PCR was used to detect NATs in U. maydis and in a related smut fungus, U. hordei. The data supported a common role for NATs in smut teliospore development, independent of the RNA interference pathway. Analysis of the expression of one U. maydis NAT, as-um02151, in haploid cells, led to a model for NAT function in U. maydis during teliospore dormancy. This model proposed NATs facilitate the maintenance of stored mRNAs through the formation of double-stranded RNA. In testing this model, it was determined that the deletion of two separate upstream regulatory regions, one of which contained a ncRNA (ncRNA1), altered NAT levels and decreased pathogenesis. These studies strengthened U. maydis as a model organism, and began the functional investigation of NATs in U. maydis, which identified a new class of fungal pathogenesis genes. Author Keywords: cDNA library analysis, genome annotation, mRNA stability, natural antisense transcripts, pathogenesis, Ustilago maydis
Abject Utopianism and Psychic Space
This dissertation utilizes the psychoanalytic theories of French psychoanalyst Julia Kristeva as a lens through which to read the novels of American author Samuel R. Delany. I argue that concepts proper to Kristeva's work--namely abjection and/or the abject--can provide a way to think what it might mean to be utopian in the 21st century. Delany's novels are received historically, which is to say his work speaks from a certain historical and cultural viewpoint that is not that of today; however, I claim that his novels are exceptional for their attempts to portray other ways of being in the world. Delany's novels, though, contain bodies, psychologies, and sexualities that are considered abject with respect to contemporary morality. Nonetheless, this dissertation argues that such manifestations of abject lived experience provide the groundwork for the possibility of thinking utopianism differently today. Throughout, what I am working toward is a notion that I call Abject Utopianism: Rather than direct attention toward those sites that closely, yet imperfectly, approximate the ideal, one should commit one's attention to those sights that others avoid, abscond, or turn their nose up at in disgust, for those are the sites of hope for a better world today. Author Keywords: Abject, Delany, Kristeva, Literary Criticism, Psychoanalysis, Utopia
Purification and Identification of Selenium-containing C-phycocyanin from Spirulina
Selenium is an essential trace nutrient to many organisms, yet in high concentrations it is toxic. Organic selenium is more bioavailable to aquatic biota than inorganic selenium, but is usually found in much lower concentrations. Algae are known to biotransform inorganic selenium into several organo-selenium compounds, but it is unknown whether any of these bioaccumulate in the food chain. In this study, selenium was incorporated into the methionine residues of an algal photosynthetic protein, c-phycocyanin from Spirulina spp. The extent of selenium incorporation was quantified by inductively coupled plasma-mass spectrometry (ICP-MS), and the protein was identified using electrospray mass spectrometry (ES-MS). C-phycocyanin was isolated and purified from Spirulina with a final recovery of 20-30 % of the total c-phycocyanin present. Selenomethionine replaced 92.8% ± 1.22 of the methionine residues in c-phycocyanin when grown in 2.5 ppm sodium selenite. ES-MS was used to obtain protein spectra, and pure c-phycocyanin was identified. Data of full scans provided estimated masses of both protein subunits--α-chain measured at 18,036 Da; β-chain measured at 19,250 Da--close to the theoretical masses. Protein fragmentation by collision-induced dissociation and electron capture dissociation provided approximately 52 % amino acid sequence match with c-phycocyanin from Spirulina platensis. This study demonstrates the incorporation of selenium into an algal protein, and the identification of c-phycocyanin using electrospray ionization-mass spectrometry. Author Keywords:
THE PROPENSITY TOWARD EXTREMIST MIND-SET AS PREDICTED BY PERSONALITY, MOTIVATION, AND SELF-CONSTRUAL
ABSTRACT The Propensity Toward Extremist Mind-Set as Predicted by Personality, Motivation, and Self-Construal Nick Fauset Multivariate regression analyses were used to determine the effects of Personality (Neuroticism, Extraversion, Openness, Agreeableness, and Conscientiousness), Motivation (External, Amotivation, Intrinsic, and Identified), and Self-Construal (Independent and Interdependent) on three domains of Extremist Mind-Set (Proviolence, Vile World, and Divine Power). Participants consisted of first year undergraduate students (209 females, 76 males) enrolled in Introductory Psychology (N=279) and/or Introductory Economics (N=7), whom participated for course credit. The Motivation measure was problematic for students to complete and this variable was dropped from the model due to missing data. Decreases in Neuroticism, Openness, Agreeableeness, and Interdependent were significantly correlated with increases in Proviolence. Decreases in Agreeableness were correlated with increases in Vile World. Decreases in Openness, and increases in Agreeableness and Interdependent were significantly correlated with increases in Divine Power. These observations provide an interesting perspective on the types of Canadian undergraduate students who are more likely to score highly on measures of Extremism. Keywords: Militant Extremist Mental Mind-Set, Extremism, Personality, Five Factor Model, Motivation, Intrinsic, Extrinsic, Self-Construal, Independent, Interdependent Author Keywords: Extremism, Militant Extremist Mental Mind-Set, Motivation, Personality, Self-Construal
Widespread changes in growth, diet and depth distribution of lake whitefish (Coregonus clupeaformis) in the Great Lakes are linked to invasive dreissenid mussels
Recent declines in growth and condition of Great Lakes' lake whitefish (Coregonus clupeaformis) have been linked to ecosystem-wide changes stemming from the invasion of dreissenid mussels. To test the influence of invasive mussels on this commercially important coregonid species, we collected archived scale samples from ten Great Lake locations and analyzed long-term changes in growth rates, delta 13C and delta 15N stable isotope ratios before and after mussel establishment. There was a decrease in pre-maturation growth after establishment in all four locations where we examined back-calculated growths. In six of the seven locations with dreissenid populations, a significant increase in delta 13C and a significant decrease in delta 15N was found. In dreissenid-absent locations of Lake Superior, we did not see changes in growth or isotope ratios indicative of a major regime shift. Observed shifts in isotopic signatures provide evidence for an increased reliance on nearshore food sources and shallower depth distribution as a result of dreissenids, which likely contributed to lowered growth of lake whitefish. Author Keywords: Diporeia, Dreissenids, food web, Great Lakes, invasive species, lake whitefish
Development and Use of Passive Samplers for Monitoring Dissolved and Nanoparticulate Silver in the Aquatic Environment
Silver nanoparticles (nAg) are the largest and fastest growing class of nanomaterials, and are a concern when released into aquatic environments even at low μg L-1+). Diffusive gradient in thin films (DGT) with a thiol-modified resin were used to detect labile silver and carbon nanotubes (CNT-sampler) were used to measure nAg. Laboratory uptake experiments in lake water provided an Ag+ DGT diffusion coefficient of 3.09 x 10 -7 cm2s-1 and CNT sampling rates of 24.73, 5.63, 7.31 mL day-1, for Ag+, citrate-nAg and PVP-nAg, respectively. The optimized passive samplers were deployed in mesocosms dosed with nAg. DGT samplers provided estimated Ag+ concentrations ranging from 0.15 to 0.98 μg L-1 and CNT-samplers provided nAg concentrations that closely matched measured concentrations in water filtered at 0.22 μm. Author Keywords: ICP-MS, mesocosms, nanoparticles, nanosilver, passive sampling
gi-mi-ni-go-wi-ni-nan o-gi-ma-wi-win zhigo o-gi-ma-win (The gifts of traditional leadership and governance)
ni' o-nah-ko-nah ah-di-so-kah-nahg zhigo di-bah-ji-mo-wi-nan g'dah mi-kwe-ni-mah-nahn obwandiacbun (nigig), tecumthabun (mizhibizhi), miinwaa shingwaukbun (ah-ji-jawk) (I ceremonially call upon the stories, the sacred and spiritual narratives and stories of personal experience... In the spirit of obwandiac, tecumtha and shingwauk) gi-mi-ni-go-wi-ni-nan o-gi-ma-wi-win zhigo o-gi-ma-win (The gifts of traditional leadership and traditional governance) explores anishinabe o-gi-ma-wi-win (traditional leadership and to be esteemed) from the point of view of obwandiac (nigig) in 1763, tecumtha (mizhibizhi) and shingwauk (ah-ji-hawk) in 1812 and 1850 respectively. It also examines the political and social significance of anishinabe o-gi-ma-win (traditional governance) and the n'swi-ish-ko-day-kawn anishinabeg o'dish-ko-day-kawn (Three Fires Confederacy) during the time of these esteemed leaders. The use of our ah-di-so-kah-nahg (sacred and spiritual stories), di-bah-ji-mo-wi-nan (stories of personal experience and reminiscences) and ah-way-chi-gay-wi-nan (moral stories) provides the opportunity to show how anishinabe people used different narratives to ah-way-chi-gay-win (teach by telling stories). In listening to these personal and intimate stories we have an opportunity to understand and explore these concepts of o-gi-ma-wi-win (traditional leadership and to be esteemed) and o-gi-ma-win (traditional governance). The first layer to this distinct way of knowing embodies anishinabe nah-nah-gah-dah-wayn-ji-gay-win (how we come to think this way about our reality and epistemology) and is expressed to us within our gah-wi-zi-maw-ji-say-muh-guhk (creation and stories of origin) and miskew ah-zha-way-chi-win (blood memory and the act of flowing). It states explicitly that we have always known where we came from, who we are, and how we fit into this world. anishinabe i-nah-di-zi-win (our way of being and way of life and ontology) lends voice to the second layer of anishinabe kayn-daw-so-win (traditional knowledge), which defines the responsibilities and expectations of anishinabe society, leadership and governance. Our ni-zhwa-sho gi-ki-nah-mah-gay-wi-nan (seven teachings), ni-zhwa-sho o-na-sho-way-wi-nan (seven sacred laws) and the relationship of the do-daim-mahg (clan system) are described within anishinabemowin, the language of our ceremonies and of the jeeskahn (shake tent). Harry Bone (2011)1, an elder from Keeseekoowenin First Nation suggests that ah-zhi-kay-ni-mo-nahd-a-di-sid bay-mah-di-sid (how we use our way of doing, thinking, ceremony and spirituality to find answers and methodology) represents a third layer that provides us with the ways and means to help us understand the essence of anishinabe nah-nah-gah-dah-wayn-ji-gay-win (how we come to think this way about our reality and epistemology and i-nah-di-zi-win (our way of being and way of life and ontology). This represents the literal and metaphoric o-dah-bah-ji-gahn (sacred bundle) and traditional approach that provides this narrative with the means to explore the ideas of leadership and governance from within a traditional construct. He adds that our spirituality and manitou kay-wi-nan (ceremonies) will be clearly defined and shared within this o-dah-bah-ji-ji-gahn (sacred bundle). It helps establish the spiritual core for this narrative. These anishinabe approaches to methodology (intimate conversations, family history and ceremony) are used to tell a story that mirrors the academic construct of interviews and document analysis. Therefore, the o-dah-bah-ji-gahn (sacred bundle) provides the nay-nahn-do-jee-kayn-chi-gayd (to dig around and research) tools to have this discussion exploring the traditional construct of anishinabe o-gi-ma-wi-win (traditional leadership and to be esteemed) and o-gi-ma-win (traditional governance). Lastly, it is important to understand that this traditional approach shows how these narratives are in-and-of-themselves powerful strategies in understanding anishinabe ah-yah-win (way of being and existence) and gah-gi-bi-i-zhi-say-mah-guhk (history). mii i'i-way anishinabe i-zhi-chi-gay-win (This is the anishinabe way) zhigo mii'iw eta-go o-way neen-gi-kayn-dahn zhigo ni-gi-noon-dah-wah (This is as much as I know and have heard) 1 Bone, Harry (Personal Communication) 2011. Author Keywords:

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Format: 2023/01/31