Search results

Title: Controlling the surface processes of X- and Z-type ligands to tailor the photophysics of II-VI semiconductor nanocrystals
Creator: Saniepay, Mersedeh
Date: 2018
Collection: Electronic Theses & Dissertations
Description: II−VI colloidal semiconductor nanocrystals (NCs), such as CdSe NCs, are often plagued by efficient nonradiative recombination processes that severely limit their use in energy-conversion schemes. While these processes are now well-known to occur at the surface, a full understanding of the exact nature of surface defects and of their role in deactivating the excited states of  NCs has yet to be established, which is partly due to challenges associated with the direct probing of the complex and...
Show moreII−VI colloidal semiconductor nanocrystals (NCs), such as CdSe NCs, are often plagued by efficient nonradiative recombination processes that severely limit their use in energy-conversion schemes. While these processes are now well-known to occur at the surface, a full understanding of the exact nature of surface defects and of their role in deactivating the excited states of  NCs has yet to be established, which is partly due to challenges associated with the direct probing of the complex and dynamic surface of colloidal NCs. In this dissertation, we report a detailed study of the surface of cadmium-rich zinc-blende CdSe NCs. The surfaces of these cadmium-richspecies are characterized by the presence of cadmium carboxylate complexes (CdX2) that act as Lewis acid (Z- type) ligands that passivate under-coordinated selenide surface species. The systematic displacement of CdX2 from the surface by N,N,N′,N′-tetramethylethylene-1,2-diamine (TMEDA) has been studied using a combination of 1H NMR and photoluminescence spectroscopies. We demonstrate the existence of two independent surface sites that differ strikingly in the binding affinity for CdX2 and that are under dynamic equilibrium with each other. A model involving coupled dual equilibria allows a full characterization of the thermodynamics of surface binding (free energy, as well as enthalpic and entropic terms), showing that entropic contributions are responsible for the difference between the two surface sites. Importantly, we demonstrate that cadmium vacancies only lead to important photoluminescence quenching when created on one of the two sites, allowing a complete picture of the surface composition to be drawn where each site is assigned to specific NC facet locale, with CdX2 binding affinity and nonradiative recombinationefficiencies that differ by up to two orders of magnitude.To understand the effect of steric hindrance and types of functional groups in different ligands on X-type ligand exchanges, using NMR, PL and UV-Vis absorption spectroscopy, we studied X-type exchanges on CdSe NCs capped with native carboxylates, with oleic acid, oleyl thiol, benzoic acid and benzenethiol ligands. We discussed the results and occurrence of undesired pathways including displacement of Z-type ligands, and suggested ligand exchange strategies that most likely lead to 100% X-type exchange.The structural complexity of surface of CdS NCs is also discussed in this dissertation. We demonstrate presence of two different sulfur surface defects on CdS NCs with ligand binding equilibrium constants that are two orders of magnitude apart and 20-60% smaller than those of selenium on similar size CdSe NCs. We also correlated the different surface defects to the PL quenching efficiency of CdS NCs.
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Title: A search for resonant Z' production in high-mass dielectron final states with the ATLAS detector in Run-2 of the Large Hadron Collider
Creator: Willis, Christopher G.
Date: 2018
Collection: Electronic Theses & Dissertations
Description: A search is performed for new resonant high-mass phenomena in the dielectron final state. The search uses 36.1 $\mathrm{fb}^{-1}$ of proton-proton collision data, collected at $\sqrt{s} = 13$ TeV by the ATLAS experiment at the Large Hadron Collider during its 2015 and 2016 data-taking runs. The dielectron invariant mass is used as the search variable. No significant deviations from the Standard Model prediction are observed. Upper limits at the 95\% credibility level are set on the cross...
Show moreA search is performed for new resonant high-mass phenomena in the dielectron final state. The search uses 36.1 $\mathrm{fb}^{-1}$ of proton-proton collision data, collected at $\sqrt{s} = 13$ TeV by the ATLAS experiment at the Large Hadron Collider during its 2015 and 2016 data-taking runs. The dielectron invariant mass is used as the search variable. No significant deviations from the Standard Model prediction are observed. Upper limits at the 95\% credibility level are set on the cross section times branching fraction to dielectron pairs for resonant $Z^{\prime}$ models considered in the search. Lower limits on the resonance pole mass are also presented. For the $Z^{\prime}_{\mathrm{SSM}}$, masses are excluded up to 4.5 TeV, while masses up to 4.1 TeV are excluded in the $E_{6}$-motivated $Z^{\prime}_{\chi}$ model. Limits are also derived in the Minimal $Z^{\prime}$ Model on the relative coupling strength $\gamma^{\prime}$. In addition, a series of studies are conducted in order to assess and reduce the dominant systematic uncertainty of this analysis, which arises from the imprecise knowledge of the Parton Distribution Functions in regions of very high parton $x$. While this uncertainty does not limit the discovery potential of the analysis presented here, it has the potential to do so in future searches. A novel approach is developed, and is shown to significantly reduce this systematic uncertainty in the high-mass search region of interest, thereby improving the discovery potential of future analyses.
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Title: "Flooding oil" : investigating poor health in vulnerable communities in the Niger Delta Region of Nigeria
Creator: Barry, Fatoumata Binta
Date: 2018
Collection: Electronic Theses & Dissertations
Description: The Niger Delta region in Nigeria has been exploited for decades due to extensive oil and gas deposits that have led to devastating livelihood and health consequences. In addition to oil and gas industry impacts, floods are intensifying in Niger Delta communities that have annual flooding during the rainy season (April to October). In 2012, Nigeria experienced a severe flooding event that damaged infrastructure and livelihoods with virtually no studies completed about the health consequences....
Show moreThe Niger Delta region in Nigeria has been exploited for decades due to extensive oil and gas deposits that have led to devastating livelihood and health consequences. In addition to oil and gas industry impacts, floods are intensifying in Niger Delta communities that have annual flooding during the rainy season (April to October). In 2012, Nigeria experienced a severe flooding event that damaged infrastructure and livelihoods with virtually no studies completed about the health consequences. This dissertation research study aims to fill this scholarly gap by disentangling the emerging health concerns in Niger Delta oil communities with particular attention to women and children as they are sensitive indicators of population health. It utilizes a mixed-methods approach with the inclusion of Eco-Syndemics and African womanism theoretical perspectives. It was found that the Niger Delta has multiple pre-existing vulnerabilities that put the population at more risk during flooding events. Also, through an evaluation of airborne concentrations of chemicals released by gas flares and a retrospective, cross-sectional comparison, women and children in Uzere (oil community) have greater exposure levels to toxic chemicals released and more health concerns than similar women and children in Aviara (non-oil community), even though both communities are located in flood-prone areas in the Niger Delta. Overall, this dissertation research advances our understanding of the complexity of health hazards in communities close to oil and gas activities in the midst of more severe flooding. It also enriches scholarly and policy debates by providing an initial assessment of the link between climate variability and health in vulnerable communities. -- Abstract.
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Title: The role of fetuin-A on adipose tissue lipid mobilization in dairy cows
Creator: Strieder-Barboza, Clarissa
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Adipose tissue (AT) is a major modulator of metabolic functions by regulating energy storage and acting as an endocrine organ. In periparturient dairy cows, increased AT mobilization of free fatty acids (FFA) is one a major adaptive mechanism to cope with higher energy demand for rapid fetal growth and the onset of lactation. As lactation progresses, lipolysis rates decrease, and lipogenesis replenishes triacylglycerol (TAG) stores in adipocytes. However, dysregulated metabolic responses,...
Show moreAdipose tissue (AT) is a major modulator of metabolic functions by regulating energy storage and acting as an endocrine organ. In periparturient dairy cows, increased AT mobilization of free fatty acids (FFA) is one a major adaptive mechanism to cope with higher energy demand for rapid fetal growth and the onset of lactation. As lactation progresses, lipolysis rates decrease, and lipogenesis replenishes triacylglycerol (TAG) stores in adipocytes. However, dysregulated metabolic responses, characterized by altered AT sensitivity to hormonal and endocrine changes around parturition, lead to a massive release of FFA into circulation and an increased susceptibility of cows to disease. These maladaptive responses are underlined by an altered secretory pattern of adipokines and a marked unbalance in lipolysis and lipogenesis rates, favoring TAG breakdown in adipocytes. Thus, identifying adipokines that modulate AT function in periparturient dairy cows can facilitate the development of novel management, nutritional, or pharmaceutical interventions to reduce disease incidence. Fetuin-A (FetA; alpha-2-Heremans-Schmid glycoprotein, AHSG) is an adipokine that functions as a carrier of FFA in plasma and is associated with insulin-mediated inhibition of lipolysis and stimulation of lipogenesis in humans. FetA increases the incorporation of fatty acids (FA) into intracellular lipids and enhances cellular TAG in human cells. However, the mechanisms by which FetA induces TAG synthesis are not defined. FetA has also anti-inflammatory properties by inhibiting the production of pro-inflammatory cytokines and acting as a negative acute-phase protein (APP) in acute inflammation. These findings suggest that FetA may also be involved in lipid mobilization and inflammation in AT of dairy cows. In our first in vivo study with periparturient dairy cows, we observed that serum and AT FetA expression decreased at the onset of lactation when lipogenesis was downregulated and plasma FFA was increased. FetA expression dynamics in AT were analogous to the patterns of lipogenic markers suggesting its link with lipid mobilization in AT of dairy cows. We also demonstrated that FetA is negative-APP locally in AT of dairy cows. These results suggest that FetA could support physiological adaptations to NEB in AT of periparturient dairy cows. To explore the potential roles of FetA on AT lipid mobilization of dairy cows, we developed an in vitro model for culturing bovine adipocytes that closely mimics the in vivo AT environment. For the first time, we reported an abundant expression and secretion of FetA by primary bovine adipocytes, thus suggesting a potential autocrine effect of FetA in AT of dairy cows. We observed that FetA attenuates lipolytic responses and enhances both, FA uptake and TAG accumulation in bovine adipocytes. Our results reveal that the upregulation of the expression and activity of 1-acylglycerol-3-phosphate acyltransferase (AGAPT2), a rate limiting lipogenic enzyme for TAG synthesis, may be a potential mechanism by which FetA enhances lipogenic function of bovine adipocytes. Overall, our results indicate that FetA is a lipogenic adipokine with anti-inflammatory function in the AT of dairy cows. Our findings provide evidence that FetA could buffer increased plasma FFA during negative energy balance by stimulating AGAPT2 activity and the use of excess FFA for TAG synthesis in AT of dairy cows. The genetic selection of cows by variations of the FetA coding gene associated with its anti-lipolytic and pro-lipogenic functions (already known in humans), the identification of dietary supplements (i.e. FA) that enhance FetA function, as well as the parenteral use of FetA to stimulate AGAPT2 activity, could serve as potential strategies to be tested and implemented in dairy cows.
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Title: Iridium catalyzed C-H activation borylations of fluorine bearing arenes and related studies
Creator: Jayasundara, Chathurika Ruwanthi Kumarihami
Date: 2018
Collection: Electronic Theses & Dissertations
Description: During the last two decades, iridium catalyzed aromatic borylation has emerged as one of the most convenient methodologies for functionalizing arenes and heteroarenes. The regioselectivity of Ir-catalyzed borylations are typically governed by sterics, therefore it complements the regioselectivity found in electrophilic aromatic substitution or directed ortho metalation. This unique regioselectivity and broad functional group tolerance (ester, amide, halogen, etc.) allows for synthesis of...
Show moreDuring the last two decades, iridium catalyzed aromatic borylation has emerged as one of the most convenient methodologies for functionalizing arenes and heteroarenes. The regioselectivity of Ir-catalyzed borylations are typically governed by sterics, therefore it complements the regioselectivity found in electrophilic aromatic substitution or directed ortho metalation. This unique regioselectivity and broad functional group tolerance (ester, amide, halogen, etc.) allows for synthesis of novel synthetic intermediates, many of which were previously either unknown or difficult to make. Since these reactions are mainly driven by sterics, it is possible to install boronic ester group (Bpin) next to small substituents like hydrogen, cyano, or fluorine. This feature is helpful but can also create challenges, specially in cases like borylation of fluoro arenes. These fluoro arenes tend give 1:1 mixture of steric (meta to fluorine) and electronic (ortho to fluorine) products. Therefore, to overcome this problem, we introduced a two-step Ir-catalyzed borylation/Pd-catalyzed dehalogenation sequence that allows one to synthesize fluoroarenes where the boronic ester is ortho to fluorine (electronic). Here, a halogen para to the fluorine is used as a sacrificial blocking group allowing the Ir-catalyzed borylation to favor the electronic product exclusively. Then the chemoselective Pd-catalyzed dehalogenation by KF activated polymethylhydrosiloxane (PMHS) is used to remove the halogen without compromising the Bpin group. Halosubstituted aryl boronates have the potential for orthogonal reactivity in cross-coupling reactions. We began exploring cross-coupling of triorganoindiums with these arylhalides bearing boronic esters in collaboration with Prof. P. Sestelo at University of da Coruña, Spain. We were able to synthesize borylated biaryls by merging Ir-catalyzed C–H borylations with Pd-catalyzed organoindium cross-couplings.As a part of the Dow–MSU-GOALI collaborations, we were able to synthesize a cobalt catalyst for C-H borylations of alkyl arenes and heteroarenes. This catalyst enables selective monoborylation of the benzylic position of alkyl arenes using pinacolborane (HBpin) as the boron source. In 2016, an internship opportunity led to the screening of ligands for C-H borylations at the Dow chemicals company in Midland, MI. From this internship opportunity, we discovered the first ligand controlled synthesis of 1,2-di and 1,2,3-tri borylated arenes. Also, I investigated a recyclable iridium heterogeneous catalyst for borylations during the internship. Finally, a bulky terphenyl incorporated bipyridine ligand is synthesized for selective iridium catalyzed para C–H borylations.
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Title: A multidimensional treatment integrity assessment of parent coaching in a telehealth parent training program for autism spectrum disorder
Creator: Tran, Shannon Quyen
Date: 2018
Collection: Electronic Theses & Dissertations
Description: An important principle of evidenced-based practice (EBP) is using interventions with strong empirical support for their effectiveness, commonly known as evidence-based interventions (EBIs). Evidence of an intervention’s effectiveness is strongest when supported by treatment integrity data. Treatment integrity refers to the degree to which an intervention is implemented as intended by the original design. The assessment’s purpose is to provide researchers and practitioners with data about the...
Show moreAn important principle of evidenced-based practice (EBP) is using interventions with strong empirical support for their effectiveness, commonly known as evidence-based interventions (EBIs). Evidence of an intervention’s effectiveness is strongest when supported by treatment integrity data. Treatment integrity refers to the degree to which an intervention is implemented as intended by the original design. The assessment’s purpose is to provide researchers and practitioners with data about the implementation process to enable valid conclusions to be drawn about an intervention’s effectiveness.The present study focused on the treatment integrity assessment of Project ImPACT (Improving Parents as Communication Teachers; Ingersoll & Dvortcsak, 2010), a parent training program that aims to improve parents’ competence in teaching social communication skills to children diagnosed with autism spectrum disorder (ASD). The parent coaching portion of the training program was the focus of this study. Treatment integrity assessment occurred at two stages: The coaching delivery and the treatment delivery.This study used videos of coaching sessions from two randomized controlled trial (RCT) studies that examined the effectiveness of delivering Project ImPACT via telehealth with and without parent coaching. Dane and Schneider’s (1998) treatment integrity conceptual framework was used to guide the assessment. For the coaching delivery, the assessment focused on the therapists’ adherence to the coaching procedure, provision of feedback, and quality of coaching delivery, and the parents’ responsiveness during the coaching session. For the treatment delivery, the assessment focused on the parents’ adherence to the intervention strategies and quality of the treatment delivery. Descriptive statistics provided a general overview of the therapists’ coaching performance and the parents’ teaching performance. Multilevel regression analysis determined which components of the coaching delivery best predicted how parents used the intervention techniques and structured the play session for their child during the coaching sessions.Overall, the therapists consistently completed the essential steps of the coaching process. They frequently provided comprehensive feedback, attention, and reassurance. They did not provide as many opportunities for the parents to engage in collaborative problem-solving or to reflect on their implementation progress. In turn, the parents fully participated in the coaching session and demonstrated sufficient capacity to implement the intervention techniques and structure a meaningful play session for their child.Results from a multilevel regression analysis indicated that none of the treatment integrity components of the coaching delivery significantly predicted the parents’ treatment adherence. The quality of coaching delivery did, however, significantly predict the parents’ structure of the play segment, albeit in a negative direction. The study’s results, along with its limitations, provided a platform for continuing the conversation about treatment integrity assessment in intervention studies. In particular, the study concluded with new questions about the conceptualization and operationalization of different parent coaching aspects for parent-implemented interventions. Seeking to understand the concept and improve the measurement of these parent coaching aspects can lead to a more accurate identification of the active ingredients of parent coaching in ASD parent-implemented interventions.
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Title: Fundamental studies and engineering modeling of hydrogen bonding
Creator: Bala Ahmed, Aseel Mohamed Ahmed
Date: 2018
Collection: Electronic Theses & Dissertations
Description: This project aims to enhance the engineering modeling of hydrogen bonding, or association, by blending ab initio quantum calculations, fundamental molecular level findings from experimental techniques, and thermodynamic models. Because of the ubiquity of hydrogen bonding, applications for an improved association model are extensive, ranging from drug design to plastics manufacturing. Therefore, a substantial amount of work has been aimed at improving traditional thermodynamic tools, which...
Show moreThis project aims to enhance the engineering modeling of hydrogen bonding, or association, by blending ab initio quantum calculations, fundamental molecular level findings from experimental techniques, and thermodynamic models. Because of the ubiquity of hydrogen bonding, applications for an improved association model are extensive, ranging from drug design to plastics manufacturing. Therefore, a substantial amount of work has been aimed at improving traditional thermodynamic tools, which often fail to capture the behavior of associating systems accurately. To guide models, spectroscopic techniques have been leveraged to gain insight into the interactions between molecules in the liquid phase, but interpretation is difficult. Moreover, with the advancement of computational chemistry technology, molecular dynamics (MD) and quantum mechanical (QM) calculations have also been utilized to understand the characteristics of hydrogen bonded clusters. However, few studies have combined all 3 techniques (the thermodynamic model, spectroscopy and ab initio calculations) in a rigorous way. To this end, an activity coefficient model for association is developed using Wertheim’s perturbation theory and its capabilities and limitations are explored with parameters from literature. Furthermore, a sequential MD and QM protocol is designed which facilitates the interpretation of the hydroxyl vibration in infrared spectroscopy and a method is developed to quantify the entire band. Finally, the methods are used to calculate the value of the association constant for an alcohol + alkane system.
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Title: Vicarious interaction with politicians by identifying with surrogates on social media : a social identification mechanism based on multiple salient social categories
Creator: Dai, Yue (College teacher)
Date: 2018
Collection: Electronic Theses & Dissertations
Description: New media platforms display politicians’ interactions with people from a variety of social categories. Previous research shows that observers could vicariously experience parasocial intimacy toward a public figure by identifying with a surrogate—an individual who directly interacts with the public figure and who is considered an ingroup member by the observer based on a salient social category (Dai & Walther, 2018). Developments in the social identity literature call for further examination...
Show moreNew media platforms display politicians’ interactions with people from a variety of social categories. Previous research shows that observers could vicariously experience parasocial intimacy toward a public figure by identifying with a surrogate—an individual who directly interacts with the public figure and who is considered an ingroup member by the observer based on a salient social category (Dai & Walther, 2018). Developments in the social identity literature call for further examination of this surrogacy effect in contexts where multiple social categories are activated as bases upon which observers identify with surrogates. Through two experiments involving a total sample of 1,068 participants, this research demonstrates that when a surrogate’s identity is presented as different combinations of political affiliation (democratic or republican) and social status (ordinary voter or politician), the more categories observers share in common with the surrogate, the more they identify with the surrogate, and thereby experiences greater parasocial intimacy toward a politician who is seen replying to the surrogate on Twitter. These findings extend previous findings on a social identification-based mechanism of the surrogacy effect and inform online impression management practices of politician.
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Title: Poly(ethylene glycol) tailored polymers : nanomicelles with tunable lower critical solution temperature behavior
Creator: Lien, Yu-Ling
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Propargyl and 1,1-dimethyl propargyl substituted poly(ethyleneoxides) (propargyl substituted = poly(PGE), 1,1ʹ-dimethyl propargyl substituted = poly(MGE)) have been prepared by ring-opening polymerization of epoxides, which were synthesized from epichlorohydrin and propargyl or 1,1-dimethyl propargyl alcohol via Williamson ether synthesis. The resulting polymers were modified by Cu-catalyzed azide alkyne cycloaddition (CuAAC) of the polymer propargyl groups and organic azides. When these...
Show morePropargyl and 1,1-dimethyl propargyl substituted poly(ethyleneoxides) (propargyl substituted = poly(PGE), 1,1ʹ-dimethyl propargyl substituted = poly(MGE)) have been prepared by ring-opening polymerization of epoxides, which were synthesized from epichlorohydrin and propargyl or 1,1-dimethyl propargyl alcohol via Williamson ether synthesis. The resulting polymers were modified by Cu-catalyzed azide alkyne cycloaddition (CuAAC) of the polymer propargyl groups and organic azides. When these reactions were carried out with mixtures of azides, the ratios of azides incorporated in the polymer side chains were equal to the molar ratios of the organic azides reactants (± 2%). Mixtures of hydrophobic (decyl azide) and hydrophilic (mDEG azide) azides result in amphiphilic polymers that exhibited a lower critical solution temperature (LCST) behavior. The polymer LCSTs scaled from 48 to 97 ± 2 °C (poly(PGE) derived amphiphiles) and 4 to 46 ± 1 °C (poly(MGE) derived amphiphiles) in a roughly linear fashion with the mole fraction of hydrophilic side chains in the polymer. When charged azides, COOH azide and aminium azide, were used, the physical property as well as the LCST behavior oh the polymers were changed. The LCSTs of polymers incorporating charged azides were increased and the LCSTs were decreased by adding salts in the solutions. The hydrodynamic radii (RH) obtained from DLS measurements indicate that polymers form unimolecular micelles in water (Mn = 52,000 g/mol, PDI = 1.19, RH = 6 ± 2 nm), and TEM data showed monodisperse domains (20 ± 4 nm, for Mn = 52,000) when water was evaporated at room temperature from solutions cast on TEM grids. This length scale is consistent with domains that consist of single polymer chains. When the TEM grid was heated during evaporation, the domain size increased to 74 ± 45 nm. In solution, the unimolecular micelles can solubilize hydrophobic small molecules, such as trans-azobenzene (trans-PhN=NPh) in water. DLS data suggested that polymer encapsulating trans-PhN=NPh (trans-PhN=NPh@poly(PGE) or poly(MGE)) derived amphiphiles) showed signs of aggregation in one case (RH = 12 ± 8 nm) and no signs of aggregation in another case (RH = 5 ± 2 nm). When the resulting solutions were raised above the polymer LCST the polymer and small molecule precipitated. When the mixture was cooled below the LCST, the polymer and hydrophobic small molecule re-dissolved. The unimolecular micelles were used to encapsulate a hydrophilic macromolecule, Subtilisin Carlsberg (SC), in aqueous solution and organic media. Poly(PGE) or poly(MGE) derived amphiphiles with COOH pendant group slowed down SC aggregation in aqueous environment. Also, the activity of SC@poly(MGE) derived amphiphiles with COOH pendant group was assayed and the half-life of SC was increased to 10 h from 2 h at 50 °C. Initial studies of SC@poly(PGE) or poly(MGE) derived amphiphiles in organic media showed enzymatic activity in toluene after 16 h at 37 °C.
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Title: Pacific Standard Time : modernism and the making of West Coast jazz
Creator: Spencer, Michael Thomas
Date: 2011
Collection: Electronic Theses & Dissertations
Description: An interdisciplinary study of one of the most overlooked and understudied movements in the history of jazz, this dissertation draws from the fields of New Jazz Studies, Popular Culture Studies, and Art History in order to reconstruct the cultural history of West Coast jazz. Focusing on the critical texts and institutions that allowed this movement to germinate and expand, I explore the ways in which the music was represented through various types of media: on record, on radio, on screen, in...
Show moreAn interdisciplinary study of one of the most overlooked and understudied movements in the history of jazz, this dissertation draws from the fields of New Jazz Studies, Popular Culture Studies, and Art History in order to reconstruct the cultural history of West Coast jazz. Focusing on the critical texts and institutions that allowed this movement to germinate and expand, I explore the ways in which the music was represented through various types of media: on record, on radio, on screen, in concert, and in print (i.e., record labels, radio stations, jazz periodicals, etc.). As a result, this study recontextualizes the West Coast jazz movement within the milieu of California modernism around the middle 20th century as a way to observe the broader jazz community; one which included musicians as well as photographers, painters, architects, sculptors, filmmakers, and other modernists.
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Title: Matter and energy transformation : an investigation into secondary school students' arguments
Creator: Onyancha, Kennedy M.
Date: 2010
Collection: Electronic Theses & Dissertations

Title: Toward the development of a chemo-enzymatic process for the production of next-generation taxol analogs
Creator: Ondari, Mark Evans
Date: 2010
Collection: Electronic Theses & Dissertations

Title: Two thousand years of foraging ecology in the endangered Hawaiian petrel : insights from stable isotope analysis
Creator: Wiley, Anne E.
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Recent evidence indicates that over the last 150 years, humans may have impacted seabird populations through modification of their marine food resources. Unfortunately, the high mobility and large pelagic ranges of many seabirds has resulted in a dearth of information concerning even their basic feeding habits. Here, I use stable isotope analysis to investigate the modern and ancient foraging ecology of an endangered seabird, the Hawaiian petrel (Pterodroma sandwichensis)....
Show moreRecent evidence indicates that over the last 150 years, humans may have impacted seabird populations through modification of their marine food resources. Unfortunately, the high mobility and large pelagic ranges of many seabirds has resulted in a dearth of information concerning even their basic feeding habits. Here, I use stable isotope analysis to investigate the modern and ancient foraging ecology of an endangered seabird, the Hawaiian petrel (Pterodroma sandwichensis). Stable isotopic composition of Hawaiian petrel tissues (δ13C and δ15N values) reflects trophic level and foraging location and can therefore be used to describe patterns of foraging segregation or long-term temporal variation within the species. Chapter 1 investigates isotopic variation within individual flight feathers, with the goal of designing minimally-invasive and ecologically informative sampling strategies. δ13C values increased from tip to base in all 52 feathers within the study, including 42 remiges from the Hawaiian petrel and 10 from the Newell's Shearwater (Puffinus auricularis newelli). Such a consistent trend, observable among different species and age classes, is unlikely to result from shifts in diet or foraging location during feather synthesis. Considerable variation of δ15N values was also present within feathers (average range of 1.3 / within Hawaiian petrel remiges). A sampling protocol is proposed that requires only 1.0 mg of feather and minimal preparation time. Because it leaves the feather nearly intact, this protocol will likely facilitate obtaining isotope values from remiges of live birds and museum specimens. Chapter 2 explores ecological variability among modern Hawaiian petrel populations. δ13C and δ 15N values of feathers demonstrate segregation in foraging location during both the breeding and non-breeding seasons for petrels nesting on Kauai and Hawaii. Genetic analyses based on the mitochondrial Cytochrome b gene also reveal strong differentiation: coalescent-based analyses estimate < 1 migration event per 1,000 generations. Finally, feathers from multiple age groups and islands show unexpected divergences in δD that cannot be related to variation in source water. Overall, these data demonstrate foraging and genetic divergence between proximately nesting seabird populations. This divergence occurs despite high species mobility and a lack of physical barriers between nesting sites.Chapter 3 investigates Hawaiian petrel foraging habits and inter-colony segregation over the course of approximately 2,000 years. The most pervasive temporal trend is a 1.4-2.6 / decrease in average δ15N values, which likely reflects declining trophic level over the past 300-1,000 years. Isotopic chronologies also document ca. 2,000 years of foraging segregation between Hawaiian petrel colonies, observed as a long-standing divergence in average δ15N values. The degree of foraging segregation between petrel colonies diminishes through time and correlates well with genetic population structure. Shifting foraging habits of the Hawaiian petrel may reflect relatively widespread trophic alterations in the pelagic realm of the North Pacific. Such changes in foraging are concerning, given their implications for reproductive success and genetic diversity.
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Title: Rater effects in ITA testing : ESL teachers' versus American undergraduates' judgments of accentedness, comprehensibility, and oral proficiency
Creator: Hsieh, Ching-Ni
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Second language (L2) oral performance assessment always involves raters' subjective judgments and is thus subject to rater variability. The variability due to rater characteristics has important consequential impacts on decision-making processes, particularly in high-stakes testing situations (Bachman, Lynch, & Mason, 1995; A. Brown, 1995; Engelhard & Myford, 2003; Lumley & McNamara, 1995; McNamara, 1996). The purposes of this dissertation study were twofold. First, I wanted to examine rater...
Show moreSecond language (L2) oral performance assessment always involves raters' subjective judgments and is thus subject to rater variability. The variability due to rater characteristics has important consequential impacts on decision-making processes, particularly in high-stakes testing situations (Bachman, Lynch, & Mason, 1995; A. Brown, 1995; Engelhard & Myford, 2003; Lumley & McNamara, 1995; McNamara, 1996). The purposes of this dissertation study were twofold. First, I wanted to examine rater severity effects across two groups of raters, English-as-a-Second-Language (ESL) teachers and American undergraduate students, when raters evaluated international teaching assistants' (ITAs) oral proficiency, accentedness, and comprehensibility. Second, I wanted to identify and compare rater orientations, that is, factors that drew raters' attention when judging the examinees' oral performances. I employed both quantitative and qualitative methodologies to address these issues concerning rater effects and rater orientations in the performance testing of ITAs at a large Midwestern university. Thirteen ESL teachers and 32 American undergraduate students participated in this study. They evaluated 28 potential ITAs' oral responses to the Speaking Proficiency English Assessment Kit (SPEAK). Raters evaluated the examinees' oral proficiency, accentedness, and comprehensibility, using three separate holistic rating scales. Raters also provided concurrent written comments regarding their rating criteria and participated in one-on-one interviews that explored raters' rating orientations. I employed a many-facet Rasch measurement analysis to examine and compare rater severity across rater groups using the computer program FACETS. I compared the written comments across groups to identify major rating criteria employed by the ESL teachers and the undergraduates. I analyzed the interview data to explore the reasons for rating discrepancies across groups. Results of the study suggested that the ESL teachers and the undergraduate raters did not differ in severity with respect to their ratings of oral proficiency. However, the comparisons of ratings in accentedness and comprehensibility were both statistically significant. The undergraduate raters were harsher than the teacher raters in their evaluations of examinees' accentedness and comprehensibility. Additionally, the analysis of the written comments identified six major rating criteria: linguistic resources, phonology, fluency, content, global assessment, and nonlinguistic factors. Cross-group comparisons of the rating criteria indicated that the undergraduate raters tended to evaluate the examinees' oral performances more globally than the ESL teachers did. In contrast, the ESL teachers tended to use a wider variety of rating criteria and commented more frequently on specific linguistic features. The interview protocols revealed that raters' experience with accented speech, perceptions of accent as an important rating criterion, and approaches to rating (i.e. analytical or global), had important bearings on raters' judgments of ITA speech.
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Title: Hydraulic evaluation of lysimeters versus actual evapotranspirative caps
Creator: Mijares, Ramil Garcia
Date: 2011
Collection: Electronic Theses & Dissertations
Description: The ability to quantify percolation through a soil profile is one of the important considerations for geoenvironmental systems. Reliable estimates of percolation through natural soil deposits help in determining local groundwater recharge rates. For landfills, accurate measurement of percolation through the cap is necessary for permitting earthen final covers. Even though percolation is generally the smallest component among water balance parameters, quantifying its magnitude is...
Show moreThe ability to quantify percolation through a soil profile is one of the important considerations for geoenvironmental systems. Reliable estimates of percolation through natural soil deposits help in determining local groundwater recharge rates. For landfills, accurate measurement of percolation through the cap is necessary for permitting earthen final covers. Even though percolation is generally the smallest component among water balance parameters, quantifying its magnitude is environmentally critical and key in evaluating the overall hydraulic performance of final covers. Direct estimation of percolation through a soil cover is typically achieved using pan lysimeters which consist of a drainage layer underlain by an impermeable geomembrane liner. The presence of this hydraulic barrier in lysimeter, which is used to facilitate the collection and measurement of percolation, alters the hydraulics of the system. This dissertation aimed to evaluate the difference in hydraulic performance of a lysimeter versus actual earthen cap with underlying landfilled waste. Two uncompacted and one compacted field-scale earthen cap test sections were built and instrumented at a landfill near Detroit, Michigan to investigate the hydraulic difference between an actual cap (underlain by waste) and corresponding lysimeter which was used to directly measure percolation. Lysimeter pans were installed in the middle of each test sections and the instrumented area was expanded upslope and downslope of the lysimeter to monitor the soil water storages within and beyond the lysimeter footprint. About 35 sensors were installed in each of the test sections to monitor water contents, water potentials, soil temperatures, water levels, and gas pressures. The field results show soil water storage values for the uncompacted test sections that were underlain by waste were typically greater than those for the corresponding lysimeters. For the compacted test section, there was no significant difference between the soil water storage for the actual cap and the lysimeter. Using the single porosity numerical models UNSAT-H and Vadose/W, the field measured percolation in the lysimeter as well as the variation in soil water storages were predicted with an acceptable accuracy for the compacted test section. The presence of macropore flow through large clods in uncompacted test sections is not accounted for in these single porosity models. A numerical analysis showed that when a lysimeter underestimates the soil water storage of an actual earthen cap, it corresponds to greater actual percolation across the interface between the soil cover and the underlying waste. A lysimeter overestimates percolation because the infiltrated water drained into the lysimeter is immediately removed and is therefore not available for removal by evapotranspiration. Field-scale simulations also showed that the magnitude of capillary barrier effect introduced by the drainage layer in the lysimeters is negligible when the saturated hydraulic conductivity of the soil cover is equal to or less than 10^-5 cm/s.
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Title: Predicting differential item functioning in cross-lingual testing : the case of a high stakes test in the Kyrgyz Republic
Creator: Drummond, Todd W.
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Cross-lingual tests are assessment instruments created in one language and adapted for use with another language group. Practitioners and researchers use cross-lingual tests for various descriptive, analytical and selection purposes both in comparative studies across nations and within countries marked by linguistic diversity (Hambleton, 2005). Due to cultural, contextual, psychological and linguistic differences between diverse populations, adapting test items for use across groups is a...
Show moreCross-lingual tests are assessment instruments created in one language and adapted for use with another language group. Practitioners and researchers use cross-lingual tests for various descriptive, analytical and selection purposes both in comparative studies across nations and within countries marked by linguistic diversity (Hambleton, 2005). Due to cultural, contextual, psychological and linguistic differences between diverse populations, adapting test items for use across groups is a challenging endeavor. Of paramount importance in the test adaptation process is the proven ability of test developers to adapt test items across groups in meaningful ways. One way investigators seek to understand the level of item equivalence on a cross-lingual assessment is to analyze items for differential item functioning, or DIF. DIF is present when examinees from different language groups do not have the same probability of responding correctly to a given item, after controlling for examinee ability (Camilli & Shephard, 1994). In order to detect and minimize DIF, test developers employ both statistical methods and substantive (judgmental) reviews of cross-lingual items. In the Kyrgyz Republic, item developers rely on substantive review of items by bi-lingual professionals. In situations where statistical DIF detection methods are not typically utilized, the accuracy of such professionals in discerning differences in content, meaning and difficulty between items is especially important. In this study, the accuracy of bi-linguals' predictions about whether differences between Kyrgyz and Russian language test items would lead to DIF was evaluated. The items came from a cross-lingual university scholarship test in the Kyrgyz Republic. Evaluators' predictions were compared to a statistical test of "no difference" in response patterns by group using the logistic regression (LR) DIF detection method (Swaminathan & Rogers, 1990). A small number of test items were estimated to have "practical statistical DIF." There was a modest, positive correlation between evaluators' predictions and statistical DIF levels. However, with the exception of one item type, sentence completion, evaluators were unable to predict which language group was favored by differences on a consistent basis. Plausible explanations for this finding as well as ways to improve the accuracy of substantive review are offered. Data was also collected to determine the primary sources of DIF in order to inform the test development and adaptation process in the republic. Most of the causes of DIF were attributed to highly contextual (within item) sources of difference related to overt adaptation problems. However, inherent language differences were also noted: Syntax issues with the sentence completion items made the adaptation of this item type from Russian into Kyrgyz problematic. Statistical and substantive data indicated that the reading comprehension items were less problematic to adapt than analogy and sentence completion items. I analyze these findings and interpret their implications to key stakeholders, provide recommendations for how to improve the process of adapting items from Russian into Kyrgyz and highlight cautions to interpreting the data collected in this study.
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Title: Institutionalization of digital literacies in four-year Liberal Arts institutions
Creator: Wendt, Mary Ellen
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Few in the field of Rhetoric and Writing debate digital literacy's value in higher level institutions today, yet while faculty in general echo this same value, the actual institutionalization of digital literacy--especially in liberal arts institutions--stands in question. This dissertation project, situated in the field of digital rhetoric and positioned theoretically with postmodern constructs, approaches research in digital literacy issues and "institutionalizing" digital literacy. I...
Show moreFew in the field of Rhetoric and Writing debate digital literacy's value in higher level institutions today, yet while faculty in general echo this same value, the actual institutionalization of digital literacy--especially in liberal arts institutions--stands in question. This dissertation project, situated in the field of digital rhetoric and positioned theoretically with postmodern constructs, approaches research in digital literacy issues and "institutionalizing" digital literacy. I examine findings using activity theory and genre theory to construct a model of the Operational Life Cycle of the Institutionalization of Digital Literacy. This model of the Operational Life Cycle has several purposes: it visually can enable others to navigate the murky journey of institutionalization; it provides a clear framework for understanding the complexities of institutional work; and it demonstrates the possibility that any size school, even with limited funds, can institutionalize digital literacy. This kind of model illuminates two ideas: One, the power of the centrifugal and centripetal outcomes (genres) of the activities in the Life Cycle, which can perpetuate and speed along such institutionalization. Two, such institutionalization requires the participation of the institution at large, English departments more specifically, and faculty members as individuals. Without such participation, holes in the Life Cycle render institutionalization of digital literacy much more difficult a challenge.
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Title: Anticipation of knowledge of success and problem-solving
Creator: Marr, John N.
Date: 1960
Collection: Electronic Theses & Dissertations

Title: Long-time convergence of harmonic map heat flows from surfaces into Riemannian manifolds
Creator: Choi, Kwangho
Date: 2011
Collection: Electronic Theses & Dissertations
Description: We study the long-time convergence of harmonic map heat flows from a closed Riemann surface into a compact Riemannian manifold. P. Topping constructed an example of a flow that does not converge in the infinite-time limit. Motivated by the observation that Topping's flow has accumulation points at which the Hessian of the energy function is degenerate, we prove convergence under the assumptions that (a) the Hessian of the energy at an accumulation point is positive definite, and (b) no...
Show moreWe study the long-time convergence of harmonic map heat flows from a closed Riemann surface into a compact Riemannian manifold. P. Topping constructed an example of a flow that does not converge in the infinite-time limit. Motivated by the observation that Topping's flow has accumulation points at which the Hessian of the energy function is degenerate, we prove convergence under the assumptions that (a) the Hessian of the energy at an accumulation point is positive definite, and (b) no bubbling occurs at infinite time. In addition, we present examples of heat flows for geodesics which show that the convexity of the energy function and convergence at infinite time may not hold even for 1-dimensional harmonic map heat flows.
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Title: Identifying Palestinians : Palestinian refugees and the politics of ethno-national identity in Jordan
Creator: Pérez, Michael Vicente
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Based on extensive research (January 2006 - January 2008) among Palestinian refugees living within United Nations Relief and Works Agency camps in Amman, Jordan, my dissertation examines how the contingencies of local and transnational politics constitute particular forms of identification that underscore the possibilities and limits of Palestinian ethnicity and nationhood. My dissertation underscores three critical issues within the process of ethno-national identification among diaspora...
Show moreBased on extensive research (January 2006 - January 2008) among Palestinian refugees living within United Nations Relief and Works Agency camps in Amman, Jordan, my dissertation examines how the contingencies of local and transnational politics constitute particular forms of identification that underscore the possibilities and limits of Palestinian ethnicity and nationhood. My dissertation underscores three critical issues within the process of ethno-national identification among diaspora Palestinians. First, my research shows how Palestinian ethno-national identifications reflect two critical issues: (1) the exclusionary discourse and practices of Transjordanian nationalists and the Jordanian State and (2) the desire to identify as Palestinians, not Jordanians. To challenge their marginalization in Jordan, Palestinians rely on pan-Arab and religious identifications that emphasize their ethno-religious commonality with Jordanians while preserving their distinct ethno-national identification as Palestinians. Second, my research demonstrates how categories of national and religious identification among refugees indicate the intersections between local concerns and transnational politics. I show how the idioms of religious nationalism articulated by refugees concerning the homeland reflect the significance of Palestinian homeland politics in Jordanian camps and offer Palestinians an opportunity to assert national identifications in a context where Palestinian nationalism is strictly controlled. Finally, my dissertation examines how the unique experience and meaning of life as a refugee in Jordan facilitates national identifications defined in terms of displacement and exile. As I show, refugee status constitutes a central point of identification among Palestinians that enables specific forms of ethnic and national belonging grounded in the experience of prolonged displacement and the myth of return.This dissertation reflects a central concern over the impact of transnational migration and displacement upon the formation and meaning of ethno-national communities and their location within the nation-state. My work examines how ethnic and national categories, whether at the level of the state, national elites, or everyday people, are produced within the nexus of local and transnational struggles that underscore the often contentious position of migrant communities within host states and homeland politics. By recognizing that the process of identification among displaced peoples reflects transnational realities, my research highlights the instability of social categories and the conditions under which they are represented, resisted, and claimed.
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