Alumni Dissertations

 

Alumni Dissertations

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  • The Effects of Thyroid Hormone Insufficiency During Development On Cortical Morphology And The Behavioural Manifestations

    Author:
    Susan Briffa-Mirabella
    Year of Dissertation:
    2013
    Program:
    Biology
    Advisor:
    Carl Dobkin
    Abstract:

    The central hypothesis of this work is that developmental thyroid insufficiency impacts the development of the rat cerebral cortex by altering cortical volume and the number of cortical neurons. In addition, as these neuroanatomical changes caused by milder forms of developmental hypothyroidism or hypothyroxinemia may have both immediate and long term consequences on certain aspects of behaviour, the investigation sought to determine if the alterations in morphology, including the change in relative cortical volume, and the change in the number of cortical neurons in the rat brain, led to behavioral manifestations. Hypothyroidism was induced by the administration of graded levels of the antithyroid agent propylthiouracil (PTU) to suppress thyroid hormone production. The number of neurons was estimated, using unbiased sampling techniques, to determine whether the cellular composition of cortex was altered following developmental TH insufficiency. To determine if these cortical alterations led to changes in behaviour, a battery of behavioural tests were performed which included maternal retrieval (PND 4), maternal separation anxiety (PND 6), Barnes maze (PND 48 and PND 86), social interaction social approach (PND 48-50), and open field (PND 46). Taken together, the results presented here support the hypothesis that developmental hypothyroidism and hypothyroxinemia induced by chemical thyroid hormone suppression (PTU) cause alterations in the morphology of the cerebral cortex by altering cortical volume and changing the number of cortical neurons in the rat brain. Furthermore these alterations ultimately lead to changes in certain aspects of behaviour. These results have important clinical relevance because several studies suggest that developmental disabilities ranging from mild dyslexia to severe mental retardation can be attributed to alterations in cortical morphology resulting from abnormal cortical development.

  • Hypertonic Lower Extremities in Infants: Correlation to Motor Function Scores at Thirteen Months of Age

    Author:
    Susan Brillhart
    Year of Dissertation:
    2013
    Program:
    Nursing Studies
    Advisor:
    Martha Whetsell
    Abstract:

    Exploring a large data set, hypertonicity of the lower extremities has been incidentally identified as occurring in one out of every five infants, whether term or preterm. This retrospective, longitudinal, descriptive, quantitative study examined data from 463 functionally and structurally normal infants and identified infants that were considered to be hypertonic at either hospital discharge and at one month of corrected gestational age to determine what their motor capabilities were at 13 months of age. Understanding the correlation will assist in determining whether early intervention is indicated for these infants. Multiple statistical analyses revealed no correlation between hypertonicity as a young infant and the Bayley-II motor function score at 13 months of age. The Roy Adaptation model was used as the conceptual framework of the study and ordinal regression was utilized to analyze the data.

  • Moving Beyond Mirroring - A social Affordance Model of Sensorimotor Integration during Action Perception

    Author:
    Maria Brincker
    Year of Dissertation:
    2010
    Program:
    Philosophy
    Advisor:
    Jesse Prinz
    Abstract:

    The discovery of so-called `mirror neurons' - found to respond similarly to own actions and the observation similar actions performed by others - have been enormous influential in the cognitive sciences and beyond. Due to the self-other symmetry these neurons have been hypothesized as underlying a `mirror mechanism' that lets us share representations and thereby ground core social cognitive functions from intention understanding to linguistic abilities and empathy. I argue that mirror neurons are important for rather different reasons. Rather than a symmetric ubiquitous or context-independent mechanism, I propose that these neurons are part of broader sensorimotor integrative circuits, which help us navigate and predict the social affordance space that we meet others in. To develop both the critical and positive project I discuss the interpretive choices and the debate surrounding the mirror neuron research and show how the field is marred by highly questionable assumptions about motor and social cognition. The very discovery of mirror neurons and the broader sensorimotor fronto-parietal circuits of which these neurons are a part, actually challenge many of these tacitly held assumptions empirically. The findings of sensorimotor goal representations at levels of abstraction well beyond the actual sensory information and kinetic movements challenge the idea of motor cognition as primarily output production. Additionally, the focus on social cognition as a process of 3rd person mindreading and attribution of hidden mental states seems misguided given that sensorimotor processes precisely suggest a developmentally primary 2nd person understanding of the mental lives and actions of others. I propose a Social Affordance model suggesting that the broader sensorimotor findings in fronto-parietal circuits support representations not just of other people's actions but of the overall social affordance space. It is a process that monitors concrete goals and teleological possibilities that the environment affords respectively oneself and other present agents. With this model I hypothesize that the complex spectrum of parallel sensorimotor integrations are indeed essential not only to normal action choices but also to social cognitive abilities, as the sensorimotor teleological representations let us relate to others and understand their action choices in a shared pragmatic and intentional context.

  • Evolution of Innate Immunity in African Catarrhines

    Author:
    Jessica Brinkworth
    Year of Dissertation:
    2012
    Program:
    Anthropology
    Advisor:
    Ekaterina Pechenkina
    Abstract:

    Innate immunity is the first line of host defense against invading pathogens, involves activation of innate immune cells via Toll-like receptors (TLRs) and is a major factor affecting host susceptibility to infectious disease. African catarrhine primates share high genomic identity, yet appear to differ in their susceptibility to bacterial infections (i.e. Gram-negative bacterial sepsis, Neisseria gonorrhoeae, Mycobacterium). These species are hypothesized to have divergent evolutionary histories of pathogen exposure due to differences in geographic distribution and behaviour. The goals of this research were to 1) clarify if the early innate immune responses of African catarrhine species have functionally diverged, and 2) examine possible associations between these responses and pathogen type, primate evolutionary landscape and disease susceptibility. To examine if African catarrhines have evolved different early innate immune responses to environment-specific pathogens, fresh whole blood from Homo, Pan and Papio was stimulated with TLR2 and TLR4 -detected molecular components from pathogens unevenly distributed across primate evolutionary habitats (i.e. Mycobacterium, Yersinia pestis) for 90 minutes. Immune activation was assessed by quantifying expression of genes associated with the early innate immune response by real-time PCR. This study shows that Homo and Pan blood leukocytes typically mount similar early cytokine and chemokine responses to stimuli, while the more distantly related Papio mounts opposing responses. The divergence of Homo/Pan and Papio cytokine/chemokine induction broadly agrees with observed differences in susceptibility to bacterial diseases, however no association was found between putative pathogen/primate evolutionary environment and gene induction. While early innate immune responses tend to agree with primate evolutionary relationships, there are some notable exceptions to this pattern, including some cytokine responses that are agonist/pathogen-specific (i.e. IL-1β, TNFα, IL-10, IL-6). Taken together, this data suggests a significant divergence between hominoid and baboon early innate immune responses since these species shared a last common ancestor 23-29 million years ago.

  • Historical Relationships between Land Elevation and Socioeconomic Status in New York City: A Mixed Methods GIS Approach

    Author:
    Jennifer Brisbane
    Year of Dissertation:
    2014
    Program:
    Earth & Environmental Sciences
    Advisor:
    Juliana Maantay
    Abstract:

    The role that topography has played in the development of New York City is essential to understanding its present urban form and foreseeing its changes. Geographers and economists have generally agreed that for cities in the United States, socioeconomic status increases with land elevation. This seemingly simple relationship between elevation and class, however, is complicated by factors such as technological innovations, economic shifts, politics, cultural perceptions, and the idiosyncrasies of cities and the neighborhoods within them. The lack of comprehensive research in this area coupled with conflicting findings warranted further exploration into the complex and changing relationships between elevation and social class. This longitudinal study utilized a mixed methods GIS approach to reveal historical relationships between land elevation and socioeconomic status in New York City, and explain factors that may mediate these relationships. This study departed from the traditional use of regression results by mapping standardized residuals clusters, which were found to be an extremely efficient way of pinpointing anomalous areas that would be appropriate case study areas for in-depth, qualitative analysis. Relative elevation was found to be a better determinant of socioeconomic status than absolute elevation for three out of ten analysis years examined. The presence of urban fringe uses on high elevation land was affirmed. The persistence of historical settlement patterns was also affirmed, and it was found that this persistence was able to withstand technological, economic, cultural, and significant physical topography changes. Public policy, such as through the use of zoning tools and eminent domain, was the most influential force in the transformation of historical land use and settlement patterns. Climate change is poised to become another powerful force in the transformation of cities, and should be incorporated into future studies that examine the relationship between physical topography and residential or land use patterns.

  • Entropy of Jammed Granular Matter

    Author:
    Christopher Briscoe
    Year of Dissertation:
    2009
    Program:
    Physics
    Advisor:
    Hernan Makse
    Abstract:

    Granular matter can be considered a non-equilibrium system, such that equilibrium statistics is insufficient to describe the dynamics. A phase transition occurs when granular materials are compressed such that a nonzero stress develops in response to a strain deformation. This transition, referred to as the jamming transition, occurs at a critical volume fraction, depending on friction and preparation protocol. Analysis of the jamming transition produces a phase diagram of jammed granular matter for identical spheres, characterized by the critical volume fraction, and the average coordination number. The boundaries of the phase diagram are related to well-defined upper and lower limits in the density of disordered packings; random close packing (RCP) and random loose packing (RLP). Frictional systems, such as granular matter, exhibit an inherent path dependency resulting in the loss of energy conservation, an important facet of equilibrium statistics. It has been suggested Edwards that the volume-force (V-F) ensemble, wherein volume replaces energy as the conservative quantity, may provide a sufficient framework to create a statistical ensemble for jammed granular matter. Treating a jammed system via the V-F ensemble introduces an analogue to temperature in equilibrium systems. This analogue, "compactivity", measures how compact a system could be and governs fluctuation in the volume statistics. Randomness in statistical systems is typically characterized by entropy, the equation of state derived from the number of microstates available to the system. In equilibrium statistical mechanics, entropy provides the link between these microstates and the macroscopic thermodynamic properties of the system. Therefore, calculating the entropy within the V-F ensemble can relate the available microscopic volume for each grain to the macroscopic system properties. The entropy is shown to be minimal at RCP and maximal at the minimum RLP limit, via several methods utilizing simulations and theoretical models. Within this framework RCP is achieved in the limit of minimal compactivity and RLP is achieved in the limit of maximal compactivity. The boundaries of a phase diagram for jammed matter could thereby be defined by the limits of zero and infinite compactivities, characterizing the RCP and RLP limits of granular matter.

  • Courting Utopia: The Romance Plot in Contemporary Utopian Fiction

    Author:
    Katherine Broad
    Year of Dissertation:
    2012
    Program:
    English
    Advisor:
    Carrie Hintz
    Abstract:

    Utopian literature is typically read as a transformative genre that compels readers to rethink the norms and assumptions that govern their worlds. But what kinds of imaginative work does the genre perform with regards to women's status in the ideal society, and how has this work developed--or failed to--in more recent utopian texts? Courting Utopia: The Romance Plot in Contemporary Utopian Fiction focuses on a specific subgenre of utopian literature known as the feminist critical utopia, which emerged in the 1970s out of previous utopian genres and continues to develop today. Despite the genre's aspirations for social change, however, I observe an ongoing refusal to challenge, let alone transform, normative gender roles in feminist critical utopian texts, a limitation that persists because the novels remain wedded to traditional narrative conventions carried over from earlier utopian forms. Ultimately, the genre remains predominantly structured not around the rhetoric of social change, as utopian scholars generally presume, but around the rhetorics of romance. Looking at the work of Marge Piercy, Margaret Atwood, and Ursula K. Le Guin, who have been central to defining the field, as well as recent popular novelists Suzanne Collins and Scott Westerfeld who show where the feminist critical utopia is moving in the twenty-first century, I detail how the romance plot undermines the feminist utopian project by restricting the utopian imagination to traditional gender roles. Identifying romance as a key obstacle to the imagining of more radical forms of social change, I break company with those who see authors like Piercy, Atwood, and Le Guin as the paragons of the genre and instead look to Robert C. O'Brien, Samuel R. Delany, and finally Toni Morrison for alternative narratives that move beyond romance to reimagine feminist critical utopian worlds. The persistence of the romance plot in contemporary feminist critical utopias has been largely overlooked by utopian scholarship, but contending with how this pervasive plotline shapes utopian possibilities stands to offer new insights into the development of more open, oppositional, and liberatory female characters and feminist alternatives to the status quo.

  • Mensura Incognita: Queer Kinship, Camp Aesthetics, and Juvenal's Ninth Satire

    Author:
    Michael Broder
    Year of Dissertation:
    2010
    Program:
    Classics
    Advisor:
    Craig Williams
    Abstract:

    The dissertation addresses four problematic aspects of scholarship on Juvenal 9. The first two are matters of reception history: first, the poem has been understudied; and second, most major extant studies of the poem have been grossly or subtly homophobic. The other two problems are matters of literary criticism: Juvenal's ninth satire has traditionally been read as an attack on homosexuality, when in fact it is neither an attack, nor is it about homosexuality. The current study addresses each of these problems, reassessing the ninth satire in the context of queer theory and camp aesthetics. Chapter One traces the homophobic tendencies in the modern reception of Juvenal 9 across reception modalities including expurgation, biographical criticism, and persona theory. Chapter Two reviews relevant concepts in queer theory and the discourse of camp. Queer theory emphasizes the performative dimensions of sex, gender, and kinship. Camp is a counter-normative discourse in which incongruous situations and juxtapositions are presented in a theatrical manner for humorous effect, expressing the relationship of sex, gender, and kinship deviants to dominant discourses of normativity and embracing the stigmatized identity of the deviant, marginalized other. Chapter Three reviews the debate over Juvenal's moralism among scholars of satire beginning in the 1960s. This debate serves as an unwitting proxy for a debate about camp aesthetics by emphasizing the role of perverse wit in articulating a moral satiric vision. Chapter Four offers a close, detailed reading of Juvenal's ninth satire within the framework of queer theory and camp aesthetics laid out in previous chapters. The reading identifies instances of camp incongruity, theatricality, and humor, the embrace of stigmatized identity, and the expression of solidarity with the deviant. Particular emphases are the parody of social and cultural institutions such as marriage and patronage; literary genres such as epic, elegy, and declamation; and literary motifs such as servitium amoris, militia amoris, and exclusus amator, among others. A Conclusion recaps and extends some of the major contentions of the study and indicates directions for further research. Finally, an Appendix provides an original translation of Juvenal's ninth satire.

  • ECONOMIC-MINDED PARTISANS: UNDERSTANDING HOW ECONOMIC PERCEPTIONS AND POLITICAL PARTISANSHIP CONDITION VOTING BEHAVIOR

    Author:
    Michael Brogan
    Year of Dissertation:
    2009
    Program:
    Political Science
    Advisor:
    Charles Tien
    Abstract:

    In this dissertation, I will introduce a new way to understand economic voting. I argue there is an interactive relationship between how the economy and the political environment are recognized among voters when making a vote choice. The framework for determining vote choice can be explained in the following manner: (1) During economic downturns, economic perceptions are the impetus for voters' decision making; because the economy is performing poorly, voters punish the incumbent government. (2) During economic prosperity, voters focus less on the economy and more on politics; incumbent presidents are rewarded for economic prosperity to a lesser extent because voters focus primarily on political matters. (3) During periods of mixed economic performance, voters focus on the economy; however, this focus is tinged by partisan filters. My findings indicate a significant interactive relationship existing between voters' partisanship and voters' economic perceptions in voting behavior which demonstrates that voters do not uniformly engage in economic voting. The model estimates that less partisan voters are more likely to act as economic voters by rewarding (punishing) incumbents for a good (bad) economy while stronger partisans typically use their economic perceptions as a means to reinforce existing partisan preferences when making their voting decisions. 

  • A MINUS-GAMETE-SPECIFIC GENE IN FUSION-DEFECTIVE CHLAMYDOMONAS MUTANTS AND ANALYSIS OF BIOSYNTHETIC PATHWAYS UPREGULATED DURING GAMETOGENESIS

    Author:
    Dmitry Brogun
    Year of Dissertation:
    2013
    Program:
    Biology
    Advisor:
    Charlene Forest
    Abstract:

    To gain insight into the mechanism of gamete fusion during fertilization, it is crucial to identify molecular, metabolic and genetic factors required for this process. Gamete fusion in C. reinhardtii cells proceeds via four genetically defined stages: 1) flagella recognition 2) signaling 3) mating structure adhesion and 4) fusion with subsequent zygote formation. During this study we used insertional and temperature sensitive conditional mutants that do not proceed to stage 4, but can agglutinate and adhere to each other via their mating structure. A homolog of the sex-restricted HAP2/GCS1 gene has been shown to prevent gamete fusion in C. reinhardtii. A SiteFinding-PCR search was conducted on the fusion-defective Chlamydomonas insertional mutants that could not be complemented with the wild type copy of the HAP2/GCS1 gene. We confirmed that mutant clone 5 had an insert in a copia-family retrotransposon on chromosome 13. We collaborated to discover that a gene, located 3 &rsqou; to the retrotransposon is a minus-gamete specific gene (MGS). We hypothesized that MGS might be a second gene required for gamete fusion. Our main objective was to identify whether there is a defect in the DNA sequence in MGS in any of our fusion-defective mutants. We performed a chromosome walk on coding, promoter and 5 &rsqou; upstream and 3 &rsqou; downstream regulatory regions (UTR) of MGS via PCR. PCR products then where sequenced and aligned. We used qRT-PCR to determine MGS expression levels in the control and fusion defective mutants. Analysis of the sequencing and expressional results showed no defect in the MGS gene. For the systematics study we used comparative genomic and phylogenetic approaches enabling us to study metabolic pathways that are upregulated in gametes of Chlamydomonas. Congruent experimental results show that the nuclear-encoded and chloroplast localized MEP pathway leading to the biosynthesis of the isoprenoid precursor molecules is upregulated in Chlamydomonas gametes. It is expected, that the results from these studies will provide further insights into regulatory mechanisms occurring during gametogenesis, some of which might be necessary for gamete fusion in algae as well as in higher eukaryotic organisms.