Alumni Dissertations

 

Alumni Dissertations

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  • Vascular Endothelia Growth Factor and its Receptor VEGFR2 Regulate Synaptic Protein Levels in Rat Hippocampal Neurons

    Author:
    Qin Cao
    Year of Dissertation:
    2012
    Program:
    Biology
    Advisor:
    Patricia Rockwell
    Abstract:

    Vascular endothelial growth factor (VEGF) is a well-established angiogenic factor which also elicits protective and stimulatory effects on neuronal function. Recent studies suggest that VEGF signaling plays a critical role in modulating synaptic plasticity and enhances excitatory synaptic transmission in the hippocampus. Other growth factors including brain-derived neurotrophic factor (BDNF) and insulin have been shown to regulate synaptic ¬¬¬protein levels to stimulate neural communication but it remains unclear how VEGF participates in synapse function at the molecular level. The notion that VEGF would also modulate synaptic protein levels in differentiated hippocampal neurons has not been explored. Therefore, this work addressed whether VEGF exhibits neurotropic properties in mature rat hippocampal neurons by modulating the postsynaptic protein PSD-95 and protecting against the stress induced by nutritional deprivation. The results show that VEGF signals an increase in cell viability and increases the levels of presynaptic (synaptophysin and synapsin I) and postsynaptic (PSD-95) proteins through its cognate receptor VEGFR2. VEGF signals these events via autocrine and paracrine mechanisms. Moreover, VEGF regulates PSD-95 protein levels and synapse numbers along dendrites through the PI3K/Akt/mTOR pathway. Additional studies showed that inhibition of the Rho-associated protein kinase (ROCK) increased PSD-95 protein levels which were attenuated by VEGFR2 inhibition. Furthermore, ROCK inhibition enhanced VEGF-mediated synapse formation, survival and neurite extension. Accordingly, these findings suggest that ROCK serves as a negative regulator of VEGF signaling in mature primary hippocampal neurons. Collectively, this study revealed a novel signaling mechanism for VEGF/VEGFR-2 pathway that may function in its reported capacity to stimulate synaptic transmission. These findings implicate VEGF signaling as a potential therapeutic strategy to prevent or hinder synaptic loss in neurodegenerative disorders.

  • Horava Gravity: Symmetries and Generalized Particle Dynamics

    Author:
    Dario Capasso
    Year of Dissertation:
    2011
    Program:
    Physics
    Advisor:
    Alexios Polychronakos
    Abstract:

    In the search for a theory of Quantum Gravity a new proposal was recently made by P. Horava. The main feature of this new proposed theory is that it is power-counting renormalizable by construction, and could prove to be truly renormalizable, although more work is needed in this direction. The renormalizability of the theory is a central issue. Indeed, General Relativity does not have this property, implying that to construct its quantum version we need to "complete" the theory in the UV. Horava suggested a possible way to provide a UV completion of GR by giving up full spacetime reparametrization symmetry, which is one of the fundamental assumptions of GR, and adding appropriate higher order terms in the action. In this Thesis we review Horava's theory and analyze some of the issues related to the breaking of the spacetime structure. Specifically, we derive the general static spherically symmetric solutions for Horava's theory with a nonvanishing radial "shift" field gtr. Such "hedgehog" configurations are not considered in GR, since gtr can be mapped to zero with an appropriate reparametrization, but they are physically distinct solutions in Horava gravity where the reparametrization is not allowed by the reduced symmetry. These new solutions exhibit specific properties from the particle dynamics point of view and possess an extra gauge symmetry. We also study the deformed kinematics of point particles allowed by the reduced reparametrization symmetry. The main result is that particles can have generalized dispersion relations that include higher even powers of the momentum. We analyze the implications of this and provide some examples that may be converted into possible experimental tests for the deviations of this new theory of gravity from standard GR.

  • REHEARSING "THE SOUTH" SICILIAN CONSTRUCTS OF REPRESENTATION ON THE STAGE 1860-1917

    Author:
    Janice Capuana
    Year of Dissertation:
    2013
    Program:
    Theatre
    Advisor:
    Marvin Carlson
    Abstract:

    My dissertation examines how theatre in Sicily after the Risorgimento may have contributed to the construction of a Sicilian identity that is considered different and other to that of northern Italy. I analyze the role that Sicilian theatre and the verismo movement played, between 1863 and 1917, in the building of a regional versus national identity through artistic cultural representations. By considering key works from this period, I posit that old and new stereotypes were reaffirmed and developed, and that native artists participated in the othering of their paesani. I also contend that the touring Sicilian acting companies in the early twentieth century, based in improvisation and folk theatre, furthered the perception of the island as exotic and different. In chapter one, I suggest that the popular play, I mafiusi, was the beginning of the mafioso anti-hero, and of the fetishization of the mafia. I focus on the context of the play and the events around its production and success, and its influence on Sicilian verismo. In chapter two, I look at how verismo, as epitomized by Giovanni Verga's Cavalleria Rusticana, created an industry for the representation of the Sicilian peasant. Using Orientalism as a lens, I argue that the parallel development of the North/South divide and meridionalismo in the new Italian state, at the same time that we see successful representations of the Sicilian in literature and theatre, helped to solidify certain negative and positive stereotypes. I also analyze Capuana's articulation of versimo as it appears in some of his theoretical works and in his play Malià. In chapter three, I turn to Sicilian dialect theatre and the famous regional actors who inspired Nino Martoglio and Luigi Pirandello to write some of their most famous characters. I argue that Martoglio's L'aria del continente and Pirandello's Liolà, while using some of the same stereotypes and tropes found in verismo just a few years earlier, now offered a lighter, gentler, comic Sicilian figure. In addition, I address the performance of these works by the actors Giovanni Grasso and Angelo Musco, and suggest that audiences perceived them as the embodiment of Sicilianness.

  • Boom and Dust: The Rise of Latin American and Latino Art in New York Exhibitions Spaces and the Auction House Market, 1970s-1980s

    Author:
    Taina Caragol Barreto
    Year of Dissertation:
    2013
    Program:
    Art History
    Advisor:
    Katherine Manthorne
    Abstract:

    Art of the Fantastic: Latin American Art 1920-1987 Hispanic Art in the United States: Thirty Contemporary Painters and Sculptors

  • Case Residuals in Structural Equation Modeling

    Author:
    John Cardinale
    Year of Dissertation:
    2011
    Program:
    Educational Psychology
    Advisor:
    John Cardinale
    Abstract:

    From the beginning, lead methodologists in psychometrics and quantitative psychology have been well aware of the problems of fitting structural and confirmatory factor models. The question we approach in our research is how to best detect this misfit and how to identify specific sources of misfit by scrutinizing the data at the case level. Since Anscombe's seminal 1973 paper, detecting problems at the case level in ordinary least-squares regression has become the norm in statistical modeling. In contrast, the usual practice in fitting structural and confirmatory factor models has been to only examine misfit at the variable and sufficient statistic level. This practice ignores a small body of literature that has arisen since the early 1990s about diagnostics of case level and case by variable level misfit. An important paper by Bollen and Arminger (1991) and a follow-up paper by Raykov and Penev (1999), have developed theory behind Individual Case Residuals (ICRs). These papers help lay the ground work for more detailed case and case by variable level diagnostics, without discarding traditional variable oriented procedures. Our goal is to demonstrate uses of multivariate techniques, such as robust Mahalanobis distances, biplots and cluster analysis to analyze the multivariate dataset of ICRs and thereby detect sources of data problems with respect to a target model. We hope to encourage researchers to make better use of case level diagnostics among the various classes of latent variable models, especially with the advent of multivariate tools in packages such as R and SAS.

  • Child Development Theory as a Mediator of Novice Teachers' Ethnotheories to Increase Learning and Justice in the Classroom

    Author:
    Nancy Cardwell
    Year of Dissertation:
    2014
    Program:
    Psychology
    Advisor:
    Colette Daiute
    Abstract:

    Many urban public schools use teaching methods that isolate and silence children to compel compliance (Schwebel, 2004; Saltman & Gabbard, 2003; Baumrind, 1991). In these contexts, black and brown children are disciplined more often and harshly than white, sent through the court system 70% of the time (Alexander, 2012). Novice teachers, appearing expert without expertise, use unconscious personal theories or ethnotheories to compel compliance, projecting an illusion of expertise without understanding the consequences for children's development and achievement (Elliott, Stemler, Sternberg, Grigorenko & Hoffman, 2010; Skovholt, 2004). An advance in the field would be to learn how ethnotheories interact with formal theories, like child development theory (CDT), to mediate pedagogical choices in the classroom. In this qualitative study, I interviewed 12 participants to learn about CDT as a mediator of classroom practice to increase learning and justice in diverse educational contexts (Daiute, 2014). I found that the unconscious use of ethnotheories reproduced injustice by subordinating children's needs to teacher's experiences and constrained learning through silencing, isolation and exclusion (Kahn & Kammerman, 2001; Harvey, 1999). I further found that the conscious use of ethnotheories mediated by CDT interrupts injustice by placing children's needs at the center and teachers adjusting their teaching approaches to create opportunities for children to tell their story, connect with each other in an inclusive, rigorous, respectful learning environment (Young, 2011; Harvey, 1999; Kenyon & Randall, 1997). Given this, teacher educators can use frequent guided reflections to support novice teachers' restorying their ethnotheories mediated through the lens of CDT situated within a global context (Kenyon & Randall, 1997). Researchers need to examine the effectiveness of this practice in relation to increasing academic achievement by investigating how novice teachers consciously use their ethnotheories mediated by CDT to adjust their teaching approaches to support increased academic success. In conclusion, CDT becomes a mediator of novice teachers' ethnotheories and a tool to adjust their classroom practice toward increased learning and justice by encouraging children to narrate their experiences to create multiple points of entry for meaningful academic lessons (Daiute, 2014; King & Cardwell, 2009; Cardwell, 2002; Kenyon & Randall, 1997).

  • Late Points of Projections of Planar Symmetric Random Walks on the Lattice Torus

    Author:
    Michael Carlisle
    Year of Dissertation:
    2012
    Program:
    Mathematics
    Advisor:
    Jay Rosen
    Abstract:

    We examine the cover time and set of late points of a symmetric random walk on Z2 projected onto the torus Z2K. This extends the work done for the simple random walk in [Late Points, DPRZ, 2006] to a large class of random walks. The approach uses comparisons between planar and toral hitting times and distributions on annuli, and uses only random walk methods. There are also generalizations of Green's functions, hitting times, and hitting distributions on Z2 and Z2K which are of independent interest.

  • THE BRAND, ME, AND THE OTHER: THE INFLUENCE OF EXTERNAL INTERPERSONAL RELATIONSHIPS ON CONSUMER-BRAND RELATIONSHIPS

    Author:
    Marina Carnevale
    Year of Dissertation:
    2012
    Program:
    Business
    Advisor:
    Lauren Block
    Abstract:

    Research suggests that people form relationships with brands in the same way they do with each other. Despite the contextual nature of relationships, the effects of external interpersonal relationships (e.g., significant others) on consumer-brand relationships remain unexplored. In the current research, I develop and test a theoretical model that explains how external interpersonal relationship dynamics impact consumer-brand relationships. Three studies show that when a product symbolizes an external relationship (e.g., through a gift scenario), changes in that relationship, such as episodes of dissolution (e.g., a break up) or reinforcement (e.g., becoming exclusive), influence the relationship that consumers have with the brand that identifies the product. Specifically, my results show that episodes of dissolution (vs. reinforcement) impact the extent to which individuals feel connected to the brand and, consequently, a series of brand-related behaviors, such as less (more) favorable attitudes, purchase intentions, and recommendation ratings. In the third study, I replicate these effects while ruling out mood as an alternative explanation. Importantly, my findings indicate that implications of interpersonal relationship episodes stretch beyond the original product to any product in a brand's portfolio. Thus, results demonstrate that consumer-brand relationships do not solely mirror human relationships - they also are affected by them. Findings also have important implications for managers promoting and positioning their brands as means of reinforcing desirable social relationships.

  • Expression, Purification, Circular Dichroism, and NMR Analysis of Triple Transmembrane Domain Containing Fragments of a GPCR

    Author:
    Katrina Caroccia
    Year of Dissertation:
    2013
    Program:
    Biochemistry
    Advisor:
    Fred Naider
    Abstract:

    G protein-coupled receptors (GPCRs) are the largest class of signaling molecules in eukaryotes and are important pharmacological targets. Structural characterization of GPCRs is of paramount importance to the discovery of more efficient drugs; however, these studies are hindered by the inherent hydrophobicity, flexibility, and large size of these signaling proteins. Since their flexibility makes crystallization difficult, stabilizing mutations or substitutions are required to facilitate crystal-packing contacts. The size of the receptor/membrane mimetic complex required for solution-state nuclear magnetic resonance (NMR) analysis is too large to enable efficient isotropic tumbling. For these reasons, high-resolution structural information is available for only thirteen of the ~1000 GPCRs identified to date. Insights into conformational preferences and the three-dimensional (3D) structure of domains of these receptors can be obtained using polypeptide fragments of these proteins. This approach is relevant because functional GPCRs can be reconstituted from fragments. Our lab has been using the yeast α-factor receptor as a paradigm for methods development for GPCR structural characterization. We have studied isolated fragments of this GPCR containing 1 and 2 transmembrane domains (TMs). For my dissertation project, I set out to characterize 3TM containing fragments of Ste2p. The goals of my project were 1) to determine whether 3TM containing fragments form more definied tertiary structures than a 2TM containing counterpart and 2) to determine whether chemical shifts from smaller fragments could be used to assign larger fragments. Two 3TM-containing fragments of Ste2p were recombinantly expressed, purified by reverse phase high performance liquid chromatography (RP-HPLC), and subjected to extensive biophysical analysis by circular dichroism (CD) and NMR spectroscopy. A 131-residue fragment containing the first 3TMs of Ste2p, TM1-TM3 (G31-R161) and a 151-residue fragment containing the first, second, and seventh TMs, TM127 (G31-T114,T274-L340) were cloned and expressed as TrpΔLE fusion proteins in Escherichia coli. The expressed proteins were subjected to CNBr cleavage to remove the fusion tag and TM1-TM3 and TM127 were purified by reverse-phase HPLC. The cleavage products were isolated in yields of up to 20 mg per liter of culture in a variety of isotopic-labeled forms. The secondary structure of TM1-TM3 and TM127 was determined to be helical in a number of membrane mimetic environments, including 2,2,2-trifluoroethanol (TFE):water and detergent micelles by CD spectroscopy. Preliminary HSQC analysis in 50% TFE:water and detergent micelles revealed that these fragments were suitable for structural analysis by NMR spectroscopy. Complete backbone and side chain assignments and a detailed localization of the secondary structural elements of TM1-TM3 in 50% TFE:water have been achieved. Under these conditions, an NMR structure was determined to have low convergence, and no tertiary contacts were observed. Attempts are currently being made to ascertain tertiary contacts by paramagnetic relaxation enhancement (PRE). NMR structural characterization of both TM1-TM3 and TM127 in detergent micelles is being conducted at the University of Zurich. To determine the transferability of chemical shifts for small to large fragments of Ste2p, two smaller constructs were analyzed. A 1TM containing fragment of Ste2p, TM1 [Ste2p(G31-T78)] was cloned into a direct expression vector and expressed with an N-terminal histidine tag in E.coli. The fragment was purified by RP-HPLC. This construct and a previously expressed TM7CT40 construct [Ste2p(S267-S339)](1) were subject to extensive heteronuclear NMR analysis in lysopalmitoylphosphatidylglycerol:dodecylphosphocholine (LPPG:DPC) micelles for backbone and side chain assignment. Backbone and side chain assignments for the TM1 fragment have been completed. Comparison of amide chemical shifts obtained for this fragment to those obtained for the TM1-TM2, TM1-TM3, and TM127 fragments of Ste2p suggests that chemical shifts are transferable for all regions except the flexible GXXXG region. A calculated NMR structure for TM1 reveals a large kink at this region. Comparison of the amide TM7 chemical shifts to those of the TM127 fragment reveals that all obtained chemical shifts are similar for this region. Detailed computational analysis is currently being performed at the Frankfurt Institute of Advanced Studies of Goethe University in order to assess complete chemical shift transferability for these fragments.

  • STRATEGIC CITIZENSHIP: DUAL MARGINALIZATION AND ORGANIZED TRANSNATIONAL POLITICAL MOBILIZATION AMONG ECUADORIAN AND DOMINICAN MIGRANTS

    Author:
    Howard Caro-Lopez
    Year of Dissertation:
    2012
    Program:
    Sociology
    Advisor:
    John Torpey
    Abstract:

    What factors define transnational political participation and citizenship for contemporary migrants? This dissertation focused on how and why migrant activists from Ecuador and the Dominican Republic pursued political engagement, how their home country governments influenced migrants' political activities, and how migrant organizations shaped their transnational activities. The study found that transnational political participation among these two populations was driven by a dual marginalization narrative, where migrants draw from their personal experiences to conclude that they are marginalized in both the U.S. and in their countries of origin based on their status as migrants. Ecuadorian and Dominican political organization leaders use this dual marginalization to create a political identity to demand minority-group rights in both home and host countries. Migrant activists make calculated decisions on where to focus their claims for rights, which I refer to as strategic citizenship Strategic citizenship is shaped by nation-state actions and local organizations. The Ecuadorian and Dominican governments influence strategic citizenship through: 1) public discourse that defines migrants' status in society; 2) the rule of law; and 3) policies that shape the state-migrant relationship. While the Ecuadorian governments' actions encouraged greater migrant participation, the Dominican government's approach was more contentious, creating skepticism among migrants towards engagement. In both cases government policy, reinforced feelings of dual marginalization. Strategic citizenship was also influenced by the different organizations in which migrant activists were involved. Migrants active in home country political parties had considerable advantages in resources and government connections, but were stifled by national party demands, member attrition and unstable leadership. Social movement and civic organizations struggled to harness resources, but had more stable leadership, more ideological autonomy and cohesive membership. I conclude that migrant political transnationalism, when examined through a contentious politics framework, originates from shared experiences engendered by the migration experience, which is reinforced by nation-state and used by organized actors frame migrant collective action. Migrants' claims for minority rights in both sending and receiving countries reflect how these actors perceive their condition to be a consequence of ruling elite actions in each country, as well as their perceived contributions as subjects of two nation-states.