Graduate Theses & Dissertations

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Short photoperiod lowers visceral adiposity and shifts the molecular clock in Peromyscus leucopus
The length of photoperiod can alter circadian rhythms and change fat depot mass whencombined with environmental temperatures below thermoneutral. To isolate photoperiod effects, we compared the effects of long and short photoperiod exposure at thermoneutrality in photoperiod sensitive, F1 generation adult male white-footed mice (P. leucopus). Mice were housed in long-day or short-day photoperiod conditions at thermoneutrality for 4 weeks. Short photoperiod decreased vWAT mass without changing body weight, scWAT or iBAT mass, or calorie consumption. Short photoperiod increased Adrβ3 and Lpl mRNA expression in vWAT with no change in Ucp1, Pgc1a or Hsl. vWAT Per1, Per2 and Nr1d1 mRNA expression were aligned to the onset of dark and food intake, while Bmal1 and Clock were misaligned. These findings suggest that short photoperiod per se can decrease visceral fat accumulation, without activating thermogenesis, reinforcing that environmental photoperiod should be considered when researching cause and prevention of obesity. Author Keywords: adiposity, circadian rhythm, clock genes, obesity, Peromyscus, photoperiod
Signalling Beliefs in Ogilby's AFRICA
This study analyzes Christian European perceptions of group identity and beliefs in early modern geographic literature, as exemplified by John Ogilby’s Africa (1670), a selective translation of Olfert Dapper’s 1668 work, and its descriptions of West-Central Africa. Ogilby’s work, congruently with contemporary geographic literature, employed the Christian religion as a key marker of group identity, using it as a lens to interpret and define the collective identities of African societies it described. Using a theoretical framework derived from Daniel Bar-Tal’s Group Beliefs, the thesis demonstrates that Africa portrayed the officially Christian kingdom of Kongo as superior to its non-Christian neighbours, consistently represented in a negative light. This attitude reflected normative European beliefs of Christian superiority fanned by the period’s intense denominationalism and religious anxiety. Africa’s general ecumenism towards other Christian denominations and its maintained “othering” of non-Christian Africans was closely linked to Ogilby’s own sense of self-identity and group beliefs shaped by his life experiences in the seventeenth-century British Isles. Author Keywords: Africa, Christianity, Identity, Kongo, Ogilby, Syncretism
Sinaakssin (writing/picture)
Assimilative policies limit and disrupt the inclusion of Aboriginal values in most Aboriginal services today. This art-based, qualitative research study approaches that issue, and using symbolism and story a sample scenario was created to demonstrate the impact of assimilative policy on Aboriginal service delivery in a storyboard format. The storyboard was then presented to four traditional thinkers who contemplated the issues therein, and as they deconstructed, considered, and conferred they resolved the matter and produced four distinct models. Imagery is relied on as a traditional means of communication to capture and convey the research issue as a painted story. This research tested the viability of using imagery as a storyboard methodology for solving social issues. By using this approach this dissertation sought to answer the question, does Indigenous knowledge have the power to change the systemic structures that surround our services. For the analysis, did the three Indigenous knowledge paradigms effectively assist in determining the nature of the Indigenous knowledge applied? Author Keywords: collective community subjectivity, Indigenous methodology, paradigms, story, symbolic communication, symbolic representation
Sinc-Collocation Difference Methods for Solving the Gross-Pitaevskii Equation
The time-dependent Gross-Pitaevskii Equation, describing the movement of parti- cles in quantum mechanics, may not be solved analytically due to its inherent non- linearity. Hence numerical methods are of importance to approximate the solution. This study develops a discrete scheme in time and space to simulate the solution defined in a finite domain by using the Crank-Nicolson difference method and Sinc Collocation Methods (SCM), respectively. In theory and practice, the time discretiz- ing system decays errors in the second-order of accuracy, and SCMs are decaying errors exponentially. A new SCM with a unique boundary treatment is proposed and compared with the original SCM and other similar numerical techniques in time costs and numerical errors. As a result, the new SCM decays errors faster than the original one. Also, to attain the same accuracy, the new SCM interpolates fewer nodes than the original SCM, which saves computational costs. The new SCM is capable of approximating partial differential equations under different boundary con- ditions, which can be extensively applied in fitting theory. Author Keywords: Crank-Nicolson difference method, Gross-Pitaevskii Equation, Sinc-Collocation methods
Situating Copper Bells in Prehispanic Southwest Societies
This thesis examines the spatial, temporal, and contextual distribution of copper bells in the Greater Southwest region and how they are situated in archaeological literature. To date, 672 copper bells have been found in at least 113 different Southwestern sites dating from ca. A.D. 900-1450, though there is no archaeological evidence for metallurgical activities in the area at this time. The origin of copper bells has been assumed to be West Mexico, a region known for its metallurgical traditions and whose inhabitants produced copious amounts of similar bells. Various lists of copper bells discovered have been compiled over the years, but little consideration has been given to the role these artifacts may have played in Southwestern societies. Copper bells are frequently labelled as prestige goods in archaeological literature, a term which fails to account for their significant depositional variation. By updating the database of known Southwestern copper bells, it becomes possible to examine these contextual distributions in greater detail. It is concluded that the prestige goods model is not suitable for Southwestern copper bells in many cases, and that alternative frameworks such as inalienable possessions are a better fit for these artifacts. Author Keywords: Archaeology, copper bells, inalienable possesions, interaction, U.S. Southwest
Size and fluorescence properties of allochthonous dissolved organic matter
Dissolved organic matter (DOM) is a mixture of molecules with dynamic structure and composition that are ubiquitous in aquatic systems. DOM has several important functions in both natural and engineered systems, such as supporting microorganisms, governing the toxicity of metals and other pollutants, and controlling the fate of dissolved carbon. The structure and composition of DOM determine its reactivity, and hence its effectiveness in these ecosystem functions. While the structure, composition, and reactivity of riverine and marine DOM have been previously investigated, those of allochthonous DOM collected prior to exposure to microbes and sunlight have received scant attention. The following dissertation constitutes the first in-depth study of the structure, composition, and reactivity of allochthonous DOM at its point of origin (i.e. leaf leachates, LLDOM), as detected by measuring its size and optical properties. Concomitantly, novel chemometric methods were developed to interpret size-resolved data obtained using asymmetrical flow field-flow fractionation, including spectral deconvolution and the application of machine learning algorithms such as self-organizing maps to fluorescence data using a dataset of more than 1000 fluorescence excitation-emission matrices. The size and fluorescence properties of LLDOM are highly distinct. Indeed, LLDOM was correctly classified as one of 13 species/sources with 92.5% accuracy based on its fluorescence composition, and LLDOM was distinguished from riverine DOM sampled from eight different rivers with 98.3% accuracy. Additionally, both fluorescence and size properties were effective conservative tracers of DOC contribution in pH-controlled mixtures of leaf leachates and riverine DOM over two weeks. However, the structure of LLDOM responded differently to pH changes for leaves/needles from different tree species, and for older needles. Structural changes were non-reversible. Copper-binding strength (log K) differed for the different fluorescent components of DOM in a single allochthonous source by more than an order of magnitude (4.73 compared to 6.11). Biotransformation preferentially removed protein/polyphenol-like fluorescence and altered copper-binding parameters: log K increased from 4.7 to 5.5 for one fluorescent component measured by fluorescence quenching, but decreased from 7.2 to 5.8 for the overall DOM, as measured using voltammetry. The complexing capacity of DOM increased in response to biotransformation for both fluorescent and total DOM. The relationship between fluorescence and size properties was consistent for fresh allochthonous DOM, but differed in aged material. Since the size and fluorescence properties of LLDOM are strikingly different from those of riverine DOM, deeper investigation into transformative pathways and mixing processes is required to elucidate the contribution of riparian plant species to DOM signatures in rivers. Author Keywords: Analytical chemistry, Chemometrics, Dissolved organic matter (DOM), Field-flow fractionation, Fluorescence spectroscopy, Parallel factor analysis (PARAFAC)
Smile and a Neutral Attitude
This thesis examines the ways in which body image is discussed in online settings. There are three different communities discussed: body positivity, proED (pro-eating disorder), and body neutrality. Both body positivity and proED content are fairly popular online, and both have found significant support and followers on various social medias. In this thesis, I argue that both of these types of content cause significant harm to those who engage with them, primarily because both communities (though different in their approaches to body image) work to uphold the thin ideal. I then bring up the third type of content: body neutrality. Body neutrality has not been given the same academic attention as body positivity and proED content, likely due to its relative infancy. In this thesis, I propose body neutrality as a much healthier way to frame body image online because of its completely neutral stance on fat, thinness, and general body image. Though any work relating to social media is quickly out of date, I hope that this thesis provides an overview of body neutrality and how, in its current form, it provides a more balanced approach to online body image discussions. Author Keywords: body image, body neutrality, body positivity, eating disorders, social media
Smote and Performance Measures for Machine Learning Applied to Real-Time Bidding
In the context of Real-Time Bidding (RTB) the machine learning problems of imbalanced classes and model selection are investigated. Synthetic Minority Oversampling Technique (SMOTE) is commonly used to combat imbalanced classes but a shortcoming is identified. Use of a distance threshold is identified as a solution and testing in a live RTB environment shows significant improvement. For model selection, the statistical measure Critical Success Index (CSI) is modified to add emphasis on recall. This new measure (CSI-R) is empirically compared with other measures such as accuracy, lift, efficiency, true skill score, Heidke's skill score and Gilbert's skill score. In all cases CSI-R is shown to provide better application to the RTB industry. Author Keywords: imbalanced classes, machine learning, online advertising, performance measures, real-time bidding, SMOTE
Social Anxiety and Emotional Competence
Prior research has examined social anxiety, emotional competence (EC) and life adjustment (i.e., loneliness and life satisfaction) using cross-sectional designs, although there is limited information on their association over time. The present study examined the impact of social anxiety on life adjustment and assessed if EC could mediate this relationship from young to middle adulthood. University students (N = 283) completed self-report measures at two time points: in first year university and 15 years later. The results accord with previous research demonstrating the stability and slight decrease of social anxiety over time. Social anxiety in young adulthood was a robust predictor of loneliness in middle adulthood, and a weak predictor of life dissatisfaction for men. Mediation analyses revealed that social anxiety was indirectly associated with interpersonal adjustment via EC, especially the intrapersonal EC domain. Social anxiety requires early intervention and EC may help to prevent later social anxiety and maladjustment. Author Keywords: emotional intelligence, life adjustment, social anxiety
Social Anxiety, Theory of Mind, and Executive Function in Late Adolescence and Early Adulthood
Studies that have investigated the relation between social anxiety and theory of mind or executive function have shown that individuals with deficits in these cognitive processes have high levels of social anxiety. However, methodological problems make past findings questionable and difficult to interpret. The current study investigated whether deficits in theory of mind and executive function predicted symptoms of social anxiety in 99 older adolescents and young adults (18-29). On average, participants had moderate levels of social anxiety. Performance on measures of theory of mind and executive function did not predict symptoms of social anxiety. This lack of associations could be due to characteristics of the current sample, methodological differences in the current study compared to past studies, or the type of social anxiety and theory of mind measure used. Implications and directions for future research are discussed. Author Keywords: Early Adulthood, Executive Function, Late Adolescence, Social Anxiety, Theory of Mind
Social Communicative Factors as Predictors of Symptom Severity in Autism Spectrum Disorders
Early diagnosis of autism spectrum disorder (ASD), while providing many benefits, presents challenges to clinicians such as predicting the stability of symptoms. Accurately predicting symptom severity allows clinicians to confidently diagnose and assign the most appropriate treatment. Little research exists to date to predict symptom severity in children with ASD who have not been exposed to treatment. The present file review examined prelinguistic skills as predictors of symptom severity in a group of young children (age: 18 – 64 months) with ASD (n = 199) who had not been exposed to significant levels of treatment. Hierarchical regression analyses demonstrated that of the two core diagnostic features (social communicative deficits and restricted repetitive behaviours), social communicative skills best predicted symptom severity. Furthermore, social communicative gestures predicted symptom severity after age, adaptive behaviour, restricted repetitive behaviours, and functional gestures had been accounted for. Author Keywords: autism, gestures, predictors, prelinguistic, social communicative, symptom severity
Social discrimination by female polar bears (Ursus maritimus) when accompanied by dependent offspring during the ice-free season in southern and western Hudson Bay and James Bay
Polar bears are generally described as solitary, but features of their life cycles and habitats regularly necessitate interaction. Effective conspecific assessment, including accurate recognition and discrimination, likely confers benefits, especially to females accompanied by dependent young. Individuals in the Southern (SH) and Western (WH) Hudson Bay subpopulations are ideal for studying polar bear social behaviours because of the prolonged high densities of the ice-free season. First, I looked outside family groups to model their fine scale sociospatial organization on land. Capture locations were more likely to correspond to family groups when there were fewer neighbouring bears, when a greater proportion of neighbours were female, and when the focal individual and neighbours were significantly related. Second, I looked within the family group to assess offspring recognition. Of 288 offspring in 207 family groups captured in the SH subpopulation from 1999 through 2013, only one case of adoption (of a singleton) was observed. Author Keywords: Adoption, Kin Recognition, Logistic Regression, Maternity Analysis, Social Discrimination, Sociospatial

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Format: 2024/03/04