Alumni Dissertations

 

Alumni Dissertations

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  • Discrimination of tone contrasts in Mandarin disyllables by naive American English listeners

    Author:
    Shari Berkowitz
    Year of Dissertation:
    2010
    Program:
    Speech & Hearing Sciences
    Advisor:
    Winifred Strange
    Abstract:

    The present study examined the perception of Mandarin disyllabic tones by inexperienced American English speakers. Participants heard two naturally-produced Mandarin disyllables, and indicated if the two were the same or different. A small native Mandarin-speaking control group participated as well. All 21 possible Mandarin contrasts where the initial syllable varied but the final syllable stayed the same were tested. Acoustic analysis was performed on the stimuli under study. Mandarin subjects scored at ceiling on all contrasts. American English subjects performed poorly on contrasts where the difference in mean F0 was small, or where the difference in the offset F0 of the first syllable was small. They also performed poorly when the difference in slope of the final syllable was small. Previous research has proposed that American English listeners attend primarily to the height difference between two tone stimuli, but here they attended to height in the first syllable and contour in the second syllable.

  • Fructose-conditioned flavor preferences in the rat: dopaminergic and opioid substrates in the nucleus accumbens and amygdala

    Author:
    Sonia Bernal
    Year of Dissertation:
    2010
    Program:
    Psychology
    Advisor:
    Richard Bodnar
    Abstract:

    Systemic dopamine (DA) D1 (SCH23390) and D2 (raclopride) receptor antagonists reduce acquisition and expression of fructose-conditioned flavor preferences (CFP) in rats. Given DA involvement in nucleus accumbens shell (NAcS) and amygdala (AMY) in learning of food reward, the first and second aims examined whether NAcS or AMY D1 or D2 antagonism altered acquisition and expression of fructose-CFP. In expression, food-restricted rats with bilateral NAcS or AMY cannulae were trained to drink a flavored fructose (8%) and saccharin (0.2%) solution or another flavored 0.2% saccharin solution. Two-bottle tests with both flavors in saccharin solutions occurred 10 min following NAcS or AMY doses of 0, 12, 24 or 48 nmol of SCH23390 or raclopride. CFP expression following vehicle (76-77%) was significantly reduced by SCH23390 (48 nmol: NAcS, 62%; AMY, 66%) and raclopride (NAcS: 24 nmol, 63%; 48 nmol, 68%). In acquisition, rats received 12 nmol of SCH23390 (D1) or raclopride (D2) in the NAcS or AMY 10 min prior to one-bottle training sessions. Yoked controls received vehicle with limited CS intakes, whereas untreated controls were not injected or limited. Two-bottle tests revealed initial CFP in all groups that remained stable in untreated and yoked controls, but were lost over six test sessions in the AMY D1 and NAcS D1 and D2 groups. Thus, D1 and D2 receptor blockade in the NAcS and AMY significantly attenuated expression, but not initial acquisition of fructose-CFP, and hastened extinction of fructose-CFP. Systemic naltrexone (NTX), an opioid receptor antagonist, suppressed sweet intake, but failed to affect acquisition or expression of fructose-CFP. Because opioids in the NAc and AMY are implicated in food reward, the third and fourth aims examined whether NTX in these sites altered expression of fructose-CFP. Food-restricted rats with bilateral NAc or AMY cannulae were trained and tested in identical protocols using NTX doses of 0, 1, 25 or 50 ug. Significant CFP was observed following all NTX doses in all sites. Thus, DA, but not opioids modulate flavor-flavor conditioning through a regionally-distributed limbic brain network.

  • The Effects of Changing Values of Concurrent Fixed Ratio Schedules on Mand Allocation in Children with Autism

    Author:
    Haven Bernstein
    Year of Dissertation:
    2010
    Program:
    Psychology
    Advisor:
    Peter Sturmey
    Abstract:

    Teaching situations with children with autism usually involve concurrent schedules of reinforcement. During concurrent schedules, manipulation of the schedule of reinforcement for one response affects the occurrence of alternative responses. This study evaluated the effects of four sets of unequal and one set of equal concurrent fixed-ratio schedules on the allocation of two mands in three children with autism. All three participants emitted a higher rate of mands for a highly preferred item than for a less preferred item determined by an initial preference assessment during a concurrent FR1/FR1 schedule. All participants increased mands for the less preferred item when the schedule value for mands for the highly preferred item was at some value greater than FR1. In terms of behavioral economics, positive cross price demand for the less preferred item as a function of increasing FR values for mands for the highly preferred item showed that all three participants substituted a less preferred item for a highly preferred item. This substitution, along with a negative own price demand for the highly preferred item as a function of increasing FR values for mands for that item, indicated some degree of demand elasticity for the highly preferred item. In addition, an increase in response variability measured by the number of switches from one mand to the other accompanied the increase in mands for the less preferred item at FR values greater than FR1 for the highly preferred item for two of the three participants. Comparison of measures of demand elasticity to more traditional measures of matching and maximization show that the former provides a more detailed account of response allocation during concurrent schedules. These finding have implications for the use of behavioral economics in the analysis of behavior change interventions during concurrent schedules in applied settings where a single behavior occurs at an inappropriate frequency and in the absence of desirable alternative behaviors.

  • Individual Differences in Electric Fishes: An Animal Model of Personality

    Author:
    Rebecca Berry
    Year of Dissertation:
    2011
    Program:
    Psychology
    Advisor:
    Christopher Braun
    Abstract:

    Individual differences in animals have recently been described in behavioral ecology as behavioral syndromes: suites of correlated behaviors within individuals that are consistent across environmental situations. A central idea behind the behavioral syndromes approach is that behaviors do not occur in isolation; rather, they are integrated with other behaviors within the limited biological machinery of one individual. Electric fish are ideally suited for studies of behavioral syndromes because their behavior can be easily measured and tracked due to their unique electric organ discharges (EODs). It is also a good system to present realistic electric signals that mimic social interactions. Using a cohort of 22 Microsternarchus sp. a neotropical knifefish, we carried out a series of behavioral experiments, including a) a free exploration experiment, b) a terrestrial challenge, c) a novelty response experiment, d) a playback experiment with an aggressive sympatric species, and e) a jamming avoidance experiment. With the exception of the playback experiment, all were performed twice on all available individuals over the course of two years. Behavioral responses including EOD rate, locomotor activity, responses to novel as well as threatening stimuli, and reaction times were measured. Through principal components analysis and correlational analysis we determined that Microsternarchus sp. exhibit behavioral syndromes in activity, reactivity, aggression/dominance and possibly behavioral flexibility, integrating electric signaling behaviors with components of exploratory behavior and responses to stimuli. For example, individuals with the highest EOD rates spent more time swimming around a novel environment, than individuals with lower EOD rates, thus these behaviors form part of an activity syndrome.

  • STOCK'S PRICE BEHAVIOUR AROUND CORPORATE MERGER AND ACQUISITION ANNOUNCEMENTS: EVIDENCE FROM THE NYSE

    Author:
    Nataliya Bershova
    Year of Dissertation:
    2010
    Program:
    Economics
    Advisor:
    Robert Schwartz
    Abstract:

    Efficient price discovery is one of the most important qualities of a financial market. Assessing a market's efficiency of price discovery is a challenging topic because efficient prices are not directly observable. It is not clear how to measure the extent to which actual prices conform to efficient prices. In this study, we use a methodology based on a state space model which deals naturally with short-term microstructure noise and enables the estimation of the unobservable prices and by implication, the pricing error. We investigate the contribution of non-instantaneous price discovery to intraday stock's price volatility around US corporate merger and acquisition announcements for a sample of 53 NYSE stocks from 2004 to 2008 using the TAQ data. Specifically, we model and estimate non-instantaneous price discovery effects that are associated with partial price adjustments to merger and acquisition (M&A) announcements for target names. We estimate price impacts from order imbalances that create pressure on a stock's price and cause a stock's price to move in a direction of order flow using one minute differencing intervals in the day of the merger news and the following day excluding the first 30 and the last 30 minutes of the trading session. Partial price adjustments may result in market over/under reaction to M&A news. To address this issue we also model and estimate market over/under reaction to merger news. We analyze the estimates of price impact and market over /under reaction to M&A announcements by contrasting the results in an M&A environment with the estimates observed in no-news days and before M&A news days. Our results shed light on price discovery around M&A announcements and its contribution to accentuated stock's price volatility. We find evidence of a protracted price discovery process following M&A news that takes at least two days after public merger announcements. Our findings reveal a significantly more informative period in two days following M&A announcements with the information flow per unit of time a factor 2 higher compared to the pre-announcement period and no-news days.

  • La poética del cuerpo en la obra de Carmen Cecilia Suárez

    Author:
    Luz Betancourt Aduén
    Year of Dissertation:
    2013
    Program:
    Hispanic & Luso Brazilian Literatures & Languages
    Advisor:
    Elena Martínez
    Abstract:

    In this Dissertation I reflected on the Poetics of the Body in the work of Carmen Cecilia Suárez, a contemporary Colombian writer and poet. I examined the literary influence of Un vestido rojo para bailar boleros (1988), which exposed the cultural patriarchal fabric that originates the colonized feminine subject in Colombia; and, in the achievement of this exposition, outstanding feminist literary critics of this country, such as María Mercedes Jaramillo, Angela Inés Robledo, Betty Osorio and Helena Araújo, were true sources of inspiration. We approached the notion of Woman focusing on the processes that favor the body as a "space of empowerment", especially acknowledging the birth of the Butterfly Woman, main metaphor of self-representation of the author; in the literary fashion of Hélène Cixous, we analyzed the struggles of hers `to speak otherwise'. Thus, Lilith became the icon whom other feminine figures depart from; the icon constitutes the core of the "aesthetics of disobedience" that in this Dissertation stems from the Argentine literary critic Susana Reisz; among those figures we literalized the Witch Woman and the Prostitute Woman. I have structured my study, with what I called the Centripetal Poetics (or the feminine individual body) and the Centrifugal Poetics (or the feminine social body); from the perspective of the first, we illustrated the "ethical conception" that resembles the philosophical approach to literature of Luce Irigaray, where the heterosexual couple becomes a "metaphor of sexual difference". It was staged in "La casa azul" of El séptimo ciclo (1992) and "Cuento de amor en cinco actos" of Cuento de amor en cinco actos (1997); in these analysis as well as the travesty performance of "Anorexia", we included important insights of Judith Butler. From the perspective of the second, we accomplished "the epic feat" of consolidating the multistratified (multifaceted-multispatial-multitemporal) Feminist Feminine Subject, called the Nomadic Woman (or in terms of our writer the New Woman); we valued the literary feminist theory of Rossi Braidotti which reflected in our exploration of several short stories of La otra mitad de la vida (2001). In the Poetics of Secret Spaces, where the author continued elaborating the postmodern condition (poscolonial, posthuman, postgender) of that Feminist Feminine Subject , we came closer to several poems of Espacios secretos (2002) and Poemas del insomnio (después del vino) (2005); we enter the field of the Cyborg Woman and the Simulacrum Woman respectively. In Retazos en el tiempo (2010), the New Butterfly Woman was born; parting from the poem "Zen", Zen was examined as an aesthetic fiction based on the "semiotics of the mandala", a formalization of a "dream of multiple dimensions" of the writer, where she continued developing her art of erotic invention, as the Poetics of Yin-Yang.

  • Being, Doing, Knowing, and Becoming: Science and Opportunities for Learning in the Out-of-School-Time Setting

    Author:
    Bronwyn Bevan
    Year of Dissertation:
    2010
    Program:
    Urban Education
    Advisor:
    Anna Stetsenko
    Abstract:

    This dissertation addresses the question of how structured out-of-school-time settings, such as afterschool programs and summer camps, are positioned to support children's engagement and learning in science. This study addresses a gap in the research literature that does not fully specify the nature of the out-of-school-time (OST) setting and that generally does not position learning and development in relationship to one another, instead focusing on one or the other. As a result of an incomplete conceptualization of the OST setting as a site for learning and development, the OST field is becoming increasingly academicized, and its developmental qualities and benefits for children are under siege. A transformative activist stance (Stetsenko, 2008) guides my goals in undertaking this study - to produce knowledge that can inform the design and implementation of OST science programs - and it also guides my analysis of what constitutes learning in OST science. A transformative activist stance is a perspective on cultural-historical theory that understands individual development as occurring through agentive, goal-directed efforts to change one's self and one's world. These goals and actions are always developed and enacted in cultural-historical context. Learning, which occurs through the appropriation of cultural tools and schema to achieve one's purposes, and which leads human development, is understood broadly, as entailing processes of being, doing, knowing and becoming (see Herrenkohl & Mertl, in press). I also draw on bioecological theory (Bronfenbrenner, 1979) to analyze the proximal processes that support and sustain children's participation in the OST setting. In this study, I analyze the structural, developmental, and conceptual features of three different OST science programs to understand how they create opportunities for learning and engagement in science. The contributions of this study are to better specify the nature of the OST science program setting and to better conceptualize how learning and development relate to one another in the context of OST science. I draw on my analysis to make recommendations for ways in which OST science learning can be expanded and enriched for more children in more settings.

  • Points of Canonical Height Zero on Projective Varieties

    Author:
    Anupam Bhatnagar
    Year of Dissertation:
    2010
    Program:
    Mathematics
    Advisor:
    Lucien Szpiro
    Abstract:

    Let k be an algebraically closed field of characteristic zero, C a smooth connected projective curve defined over k, K =k(C) the function field of C. Let Y be a projective K-variety, L a very ample line bundle on Y and α : Y &rarr Y a K-morphism such that α *<\super>L = L × d. We prove that a projective integral C-scheme Y is isotrivial when it is covered by a projective integral k-scheme X= X0<\sub> × C, where X0<\sub> is a k-scheme. This result provides a setup for a conjecture of L. Szpiro on parametrization of points of canonical height zero of the dynamical system (Y,L, α).

  • Interfacial Transport Processes Involved in the Surfactant Facilitated Wetting of Liquids on Solid Surfaces and Non-wetting on Superhydrophobic Surfaces.

    Author:
    Nikhil Bhole
    Year of Dissertation:
    2011
    Program:
    Engineering
    Advisor:
    Charles Maldarelli
    Abstract:

    The control of the wetting properties of aqueous solutions on surfaces is critical to the implementation of many industrial technologies. Aqueous solutions are often required to rapidly wet hydrophobic solid and liquid (oil) surfaces. Surfactants, dissolved above the critical micelle concentration, are useful in quickly reducing aqueous/solid and aqueous/oil tensions to facilitate spreading. In other applications, aqueous droplets are required to roll over surfaces, and surfaces engineered with textures which trap air between grooves as the drop moves over the surface retain large droplet contact angles and reduced friction, which causes rolling. The first part of this dissertation studies the transport of surfactant from an aqueous micellar solution to an oil phase, initially without surfactant, which is placed in contact with the water. Surfactant monomer diffuses and adsorbs from the aqueous phase onto the interface, and subsequently desorbs into the oil. The decrease in the surfactant monomer concentration in the vicinity of the surface disturbs the monomer-micelle equilibrium causing the micelles to break down to replenish the sublayer with monomer. The increase results in a more rapid reduction in interfacial tension. However, when the micellar concentration is too low, the micelle diffusion flux required to replenish the monomer underneath the surface cannot be achieved, and a zone is formed (just underneath the oil-water interface) from which micelles completely disappear. This micelle-free zone, which retreats from the surface, represents a barrier to the enhanced surfactant flux to the surface. A fluorescing dye is trapped in the micelles to provide a fluorescence contrast so that the micelle-free zone can be located. A Confocal Laser Scanning Microscope is used to spatially resolve the micelle-free zone, and measure the movement of the zone from the interface. A diffusion limited transport model is also developed which predicts the location of the micelle-free zone as a function of time, and compares well with the experiments. Part two of the dissertation focuses on studying the (superhydrophobic) non-wetting behavior demonstrated by aqueous droplets on surfaces consisting of a periodic array of micron-sized posts. Boundary integral hydrodynamic solutions for the two dimensional, inertialess, gravity-driven movement of a droplet over this microtexture are obtained to understand the flow on the length scale of the topography. Two regimes are identified: In one, the advancing line spreads relatively easily over the top of a post, sticks to the back of the post, develops increasing curvature and finally jumps to the next post. This cycle repeats until the drop becomes tethered to the back of a post and achieves equilibrium. In the second, the advancing line again cycles between wetting, sticking and jumping, but penetrates the grove between the posts before jumping. This behavior, which precedes the full wetting regime, occurs when the contact angle of the post material is reduced or, the pitch between posts becomes large.

  • Synthesis and characterization of Lanthanide Aluminotungstates and Rhenium Polyoxometalates: Potential Application in Molecular Information Storage Devices

    Author:
    Fang Bian
    Year of Dissertation:
    2011
    Program:
    Chemistry
    Advisor:
    Lynn Francesconi
    Abstract:

    Abstract Synthesis, speciation, and application of Polyoxometalates: Redox Molecular Information Storage Device Pre-research and Rhenium Chemistry By Fang Bian Adviser: Professor Lynn C. Francesconi Polyoxometalates (abbreviated as POMs) are metal-oxide clusters with frameworks built from group 5 or 6 transition metals linked by shared oxide ions. The Keggin structure is one of the most famous structural forms of POMs. Keggin anions have a general formula of [XM12O40]n-, where X is a p-block atom and M is a transition metal atom such as W or Mo. Upon removal of one MO4+ unit from the Keggin anion, the monovacant structure [XM11O39]n- is formed. Those POMs that have lost one or more metal center are called lacunary POMs, which are very nice building blocks for the fabrication of coordination polymers. My research focuses on two facets of POM chemistry: 1) Lanthanide chemistry of aluminum tungstate monovacant Keggin and 2) Rhenium chemistry of aluminum tungstate Keggin and Wells-Dawson POM a1-P2W17O61. In lanthanide POM research area, we obtained the following results: 1) The starting material aluminum tungstate monovacant Keggin α-K9AlW12O39 was synthesized. Its single crystal was firstly identified by multinuclear NMR and X-ray crystallography. Its redox properties on the nano-scale solid state were determined by Conducting Electrostatic Force Mode (EFM) probes. It is well known that for POMs, a number of varies redox states are normally stable and reversible. Thus we estimated that POMs can potentially be used in molecular information storage applications, which we refer to as "redox disk drives". 2) Eight lanthanide aluminum tungstate Keggin complexes were synthesized. In their molecular structures (identified by multinuclear NMR and X-ray crystallography), each α-AlW11O39 is connected by lanthanide (III) cations to form 1D and 2D networks. All AlW11O39 Keggin POMs are regularly aligning on a flat plane. Microscopic data also verified that there is layer-by-layer morphology in this series of compounds. Overall, we postulate that aluminum tungstate Keggin POMs are a very promising materials for making future information storage device because they have several stable redox states and can be reduced by adding voltage in solid state, The Keggin POMs can be regularly aligned on a flat plane, 3) In rhenium chemistry research area, we successfully synthesized rhenium complexes of the [a1-P2W17O61]10- and α-K9AlW13O39. The structure info of [ReVO(a1-P2W17O61)]7- was identified by multinuclear NMR and X-ray crystallography. The cyclic-voltammetry of [ReVO(a1-P2W17O61)]7- has also been measured and compared to the [ReVO(a2-P2W17O61)]7- isomer. A rhenium derivative of α-K9AlW11O39 also has been synthesized. Multinuclear NMR gives structure information. After oxidation in air, this compound can aggregate to form insoluble nanoparticles.