Graduate Theses & Dissertations

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Adaptive Genetic Markers Reveal the Biological Significance and Evolutionary History of Woodland Caribou (Rangifer tarandus caribou) Ecotypes
Migratory and sedentary ecotypes are phenotypic distinctions of woodland caribou. I explored whether I could distinguish between these ecotypes in Manitoba and Ontario using genetic signatures of adaptive differentiation. I anticipated that signatures of selection would indicate genetic structure and permit ecotype assignment of individuals. Cytochrome-b, a functional portion of the mitochondrial genome, was tested for evidence of adaptation using Tajima’s D and by comparing variations in protein physiology. Woodland caribou ecotypes were compared for evidence of contemporary adaptive differentiation in relation to mitochondrial lineages. Trinucleotide repeats were also tested for differential selection between ecotypes and used to assign individuals to genetic clusters. Evidence of adaptive variation in the mitochondrial genome suggests woodland caribou ecotypes of Manitoba and Ontario corresponded with an abundance of functional variation. Woodland caribou ecotypes coincide with genetic clusters, and there is evidence of adaptive differentiation between migratory caribou and certain sedentary populations. Previous studies have not described adaptive variation in caribou using the methods applied in this study. Adaptive differences between caribou ecotypes suggest selection may contribute to the persistence of ecotypes and provides new genetic tools for population assessment. Author Keywords: Adaptation, Cytochrome-B, Ecotype, RANGIFER TARANDUS CARIBOU, Selection, TRINUCLEOTIDE REPEAT
Adoption of a Finite Element Model of Material Deformation Relevant to Studying Corneal Biomechanics
The human cornea is required to exhibit specific material properties to maintain its regular shape under typical intraocular pressures which then allow for its correct optical functionality. In this thesis, the basis of continuum solid mechanics and the finite element method are introduced. We use finite element modelling to simulate the extension of an effective-1d, linear-elastic bar, a cornea-like body governed by Poisson’s equation, and the deformation of a loaded, linear-elastic, cube. Preliminary results for the deformation of a simulated, linear-elastic, cornea have also been achieved using the finite element approach. Author Keywords: continuum solid mechanics, corneal biomechanics, finite element method, intraocular pressure
Advanced broadband CARS microscopy based on a supercontinuum-generating photonic crystal fiber
I have developed and improved a coherent anti-Stokes Raman scattering (CARS) microscope based on the spectral focusing (SF) technique. The CARS microscope uses an 800 nm oscillator and a photonic crystal fibre module to generate the supercontinuum Stokes. The photonic crystal fibre was originally designed to generate light beyond 945 nm which is useful for CARS microscopy in the CH/OH frequencies but essentially prevents access to the important fingerprint region at lower frequencies. With expert and nontraditional approaches to generating supercontinuum with sufficient power at wavelengths below 945 nm, I substantially extend the usefulness of the module for SF-CARS microscopy deep into the fingerprint region. Moreover, with the invention of a dynamic supercontinuum generation scheme we call "spectral surfing," I improve both the brightness of the CARS signal and extend the accessible CARS frequency range to frequencies as low as 350 cm$^{-1}$ and as high as 3500 cm$^{-1}$---all in a single scan-window. I demonstrate the capabilities of our broadband SF-CARS system through CARS and four-wave mixing hyperspectroscopy on samples such as astaxanthin, lily pollen and glass; liquid chemicals such as benzonitrile, nitrobenzene and dimethyl sulfoxide; and on pharmaceutical samples such as acetaminophen, ibuprofen, and cetirizine. Furthermore, In search of more useful Stokes supercontinuum sources, I compare the performance of two commercial photonic crystal fibre modules for use in SF-CARS applications, ultimately finding that one module provides better spectral characteristics for static supercontinuum use, while the other provides improved characteristics when spectral surfing is implemented. Author Keywords: coherent anti-Stokes Raman scattering, nonlinear microscopy, scanning microscopy, spectroscopy, supercontinuum generation, vibrational spectroscopy
Aeolian Impact Ripples in Sand Beds of Varied Texture
A wind tunnel study was conducted to investigate aeolian impact ripples in sand beds of varied texture from coarsely skewed to bimodal. Experimental data is lacking for aeolian megaripples, particularly in considering the influence of wind speed on ripple morphometrics. Additionally, the modelling community requires experimental data for model validation and calibration. Eighteen combinations of wind speed and proportion of coarse mode particles by mass were analysed for both morphometrics and optical indices of spatial segregation. Wind tunnel conditions emulated those found at aeolian megaripple field sites, specifically a unimodal wind regime and particle transport mode segregation. Remote sensing style image classification was applied to investigate the spatial segregation of the two differently coloured size populations. Ripple morphometrics show strong dependency on wind speed. Conversely, morphometric indices are inversely correlated to the proportion of the distribution that was comprised of coarse mode particles. Spatial segregation is highly correlated to wind speed in a positive manner and negatively correlated to the proportion of the distribution that was comprised of coarse mode particles. Results reveal that the degree of spatial segregation within an impact ripple bedform can be higher than previously reported in the literature. Author Keywords: Aeolian, Impact Ripples, Megaripple, Self-organization, Wind Tunnel
After the Ash Fall
Mount Mazama, a large volcano located in the Cascade Range of Oregon, eruptedsome 7,000 cal. years BP. Following the volcanic eruption, a large portion of the northwestern region of the Great Plains of North America was covered by a thick layer of volcanic ash. The present research project is concerned with the impact of this catastrophic event on the subsistence patterns of the northwestern Plains groups during the early Archaic period (ca. 6,600–6,000 BP). More specifically, this research project tests the hypothesis that the eruption of Mount Mazama prompted the adoption of bone grease rendering in this part of the Plains. To test this hypothesis, a faunal analysis of the assemblages of Stampede site, located on the Cypress Hills of southeastern Alberta, was performed. The results of the analysis presented here show that the faunal material of the Stampede site is extensively burnt, which seems to be more in line with the intentional disposal of bones in hearth features, possibly for cleaning purposes, than with bone grease manufacture. The methodological issues regarding the identification of bone grease rendering from archaeozoological assemblages are discussed here. Author Keywords: Bone Grease Rendering, Carcass Processing Behaviour, Faunal Analysis, Great Plains, Northern Plains, Subsistence
After the Fall
Utilizing pre-existing scholarship on post-conflict reconstruction in twentieth-century Europe, as well as a variety of French primary sources, this thesis explores the concept of national-moral reconstruction as utilized by French political leaders in the wake of their country's defeat by Nazi Germany in June 1940. In particular, this study analyzes the competing discourses employed by the Vichy regime and the various organizations of the French Resistance, as each group sought to explain to a broader public both the causes of the French defeat, as well as the repercussions of the German occupation of the country from June 1940 to August 1944. While previous scholarship has emphasized the physical and/or economic dimensions of post-conflict reconstruction--especially when considered in the context of the Second World War--this thesis focuses on issues of cultural identity and national history/memory in order to look at how French political leaders hoped to reconstruct the moral and cultural, as opposed to the strictly physical, fabric of their country in the wake of the comprehensive social, political, and military disaster brought about by the German occupation. Author Keywords: collective memory, German occupation, national-moral reconstruction, Philippe Pétain, post-conflict reconstruction, Vichy France
Age-Friendly for Whom?
In this thesis, I explore the question of what would make Peterborough a good or “age-friendly” place to grow old(er) from a diversity of perspectives within and outside the structures of Age-friendly Peterborough (AFP). This research further explores if and/or how AFP and the Age-friendly movement more broadly, can be used as a tool for visioning and enacting more just, equitable, and “age-friendly” aging futures. To answer these questions I used semi-structured interviews with individuals either presently or previously involved with Age-friendly Peterborough, and an intergenerational and arts-based workshop, “Imagining our Futures.” From the research findings, I argue that AFP has a significant role to play in making Peterborough a better place to grow old(er), while also outlining how dominant Age-friendly frameworks are limited in their ability to move us towards aging futures that are just, equitable, and “age-friendly.” Author Keywords: Age-Friendly Communities, Age-Friendly Movement, Aging Futures, Arts-Based Research, Interdependence, Successful Aging
Agony of Writing Or Ambivalent Reversal In Baudrillard's Stylistic Metamorphoses
Following Baudrillard's conceptual and stylistic shift of the mid-70s, this thesis argues that said shift is accounted for by understanding the ontological quandary Baudrillard found himself in after developing a theoretical agonism impossible to divorce from the practice of writing. By tracing the conceptual metamorphoses of key terms including semiotic ambivalence, symbolic exchange and theoretical writing itself as a total agonistic process, this thesis demonstrates that theory is not reducible to epistemic production but is rather the contentious site of challenge and aesthetic (dis)appearance. Each chapter examines a conceptual tension revealing insoluble, conflicting social forms. These forms reveal the reversibility Baudrillard finds at work in all social phenomena. These culminate in a chapter that tackles Baudrillard's writing itself as a social form that endeavours to embody the agonistic theoretical concept as a process rather than remaining a representation, or commentary on, ambivalent social conflict. Author Keywords: agonist, ambivalence, Baudrillard, reversibility, style, writing
Agricultural Intensification at Cerro de Oro (Cañete Valley, Peru)
Stable carbon and nitrogen isotope analysis of 571 archaeobotanical samples was performed to assess agricultural practices at Cerro de Oro in the Cañete Valley, Peru, during the transition between the Early Intermediate Period and the Middle Horizon. This thesis presents a comprehensive range of δ13C and δ15N values for the major C3 and C4 plant resources at the site. No differences were found in the δ15N values of charred and desiccated maize cobs, suggesting that both types of plant remains can provide reliable δ15N measurements. Generally, the δ15N values of plants at the site were relatively high, with the exception of most of the legumes, suggesting that organic fertilizers were extensively used. Camelid dung and fish offal are the most likely fertilizers used at Cerro de Oro, but some very high δ15N values suggest that seabird guano may also have been used. Peanuts, a legume, had higher δ15N values than would be expected for legumes, suggesting that this plant may have been companion-planted alongside maize or other more heavily fertilizer crops. Cotton had the highest δ13C value among all of the C3 plants sampled from the site, suggesting that this crop grew in the driest conditions, possibly reflecting a deficit irrigation system. This study reveals how intensive and extensive agriculture supported the emergence and growth of Cerro de Oro, a monumental site of great regional importance. Author Keywords: Andean Archaeology, Carbon and Nitrogen Stable Isotope Analysis, Cerro de Oro, Early Intermediate Period and Middle Horizon, Intensive and Extensive Agriculture, Plants
Agriculture as Niche Construction
The Neolithic Period (c. 6200 – 4900 BC) in the Struma River Valley led to numerous episodes of cultural diversification. When compared with the neighbouring regions, the ecological characteristics of the Struma River Valley are particularly heterogeneous and the Neolithic populations must have adapted to this distinctive and localized ecological setting. It then becomes reasonable to ask if the evolution of cultural variability in the Struma River Valley was at least partially driven by the ecological setting and differentiation in the evolution of the early agricultural niche. In this thesis, I apply an approach based on niche construction theory and Maxent species distribution modeling in order to characterize the relationship between culture and ecology during each stage of the Neolithic Period and to assess diachronic change. An interpretation of the results demonstrates that the continuous reconstruction of the early agricultural niche allowed for settlement expansion into new eco-cultural niches presenting different natural selection pressures and that cultural change followed. I also found that cultural and historical contingencies played an equally important role on the evolution of populations and that ecological factors alone cannot account for the numerous episodes of cultural diversification that occurred throughout the region. Author Keywords: Agriculture, Bulgaria, Eco-cultural Niche Modeling, Greece, Neolithic, Niche Construction
Agro-Ecological Zoning (AEZ) of Southern Ontario and the Projected Shifts Caused by Climate Change in the Long-term Future
This thesis proposes an agro-ecological zoning (AEZ) methodology of southern Ontario for the characterization and mapping of agro-ecological zones during the historical term (1981-2010), and their shifts into the long-term (2041-2070) projected climate period. Agro-ecological zones are homogenous areas with a unique combination of climate, soil, and landscape features that are important for crop growth. Future climate variables were derived from Earth System Models (EMSs) using a high emission climate forcing scenario from the Intergovernmental Panel on Climate Change 5th Assessment Report. The spatiotemporal shifts in agro-ecological zones with projected climate change are analyzed using the changes to the length of growing period (LGP) and crop heat units (CHU), and their manifestation in agro-climatic zones (ACZ). There are significant increases to the LGP and CHU into the long-term future. Two historical ACZs exist in the long-term future, and have decreased in area and shifted northward from their historical locations. Author Keywords: Agro-climatic Zones, Agro-ecological Zones, Agro-ecological Zoning, Climate Change, Crop Heat Units, Length of Growing Period
Alien Imaginaries
This dissertation offers a cultural analysis of UFOs and extraterrestrials in the United States. In it I look at what I call real aliens — extraterrestrials believed to be real and interacting with humans on Earth. Beliefs in real aliens are often denigrated and dismissed in official discourse, yet they continue to not only persist, but thrive, in American society. Hence, this dissertation asks: Why do so many people believe that extraterrestrials are visiting our planet? Part One begins by tracing the invasion of real aliens in the United States using Orson Welles’s 1938 radio broadcast “The War of the Worlds” as a starting point. Here, I look at how and why the broadcast registered with listeners’ anxieties and created a fantastic and uncanny effect that made it possible for some to conceive of aliens invading the United States. In Part Two, I trace the rise of ufology, which involves the study of extraterrestrials currently interacting with humans on Earth, and I consider how the social and political climate of the Cold War, as well as the cultural environment of postmodernity, provided the necessary conditions for stories about aliens to be made believable. Part Three explores the case study of the Roswell Incident, a conspiracy theory about the origins of an alleged flying saucer crash and government cover-up. I look at the reasons for why many individuals have come to believe in this conspiracy theory and I reflect on the tensions between “official” and “unofficial” discourses surrounding this case. I also consider how and why Roswell has become such an important site for ufology, and I examine the performances given by ufologists at the annual Roswell International UFO Festival to appreciate how ufologists offers seductive explanations of why things are the way they are; for many, their stories offer a better version of events than the purely rational and positivist explanations offered by official sources, especially since they tap into the disillusionment and mistrust that many Americans feel about contemporary politics. Author Keywords: aliens/extraterrestrials, America, conspiracy, official and unofficial, storytelling, ufology

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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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