Electronic Theses and Dissertations

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About: Electronic theses and dissertations (ETDs) are the graduate research outputs of Texas Tech University. They represent years of work from our Master's and Doctoral graduates. If you find the ThinkTech digital repository useful, please tell us! Share how open access to scholarship benefits you. Your story matters to us.

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    Writing from the Margins: Transregional Approaches to Fin de Siècle American Literature
    (2018-05) Lemon, Mike
    In this project, I investigate how regional American literatures between the mid-nineteenth and early twentieth centuries create transregional discourses. A loan word from world history, transregionalism identifies economic and cultural connections across large geospatial regions. A transregional approach to American literature would serve a similar purpose, albeit at smaller spatial and cultural scales within the United States. To demonstrate these cultural discourses across regions, I propose to analyze how Theodore Dreiser, María Amparo Ruiz de Burton, Mary Austin, and Frances E. W. Harper discuss spatial and generic movements within their fiction. For the first analysis, transregional approaches to American literature uses spatial theory and critical regional studies to investigate the production of space in regional American texts. By production of space, I refer to Henri Lefebvre’s famous declaration that space is socially produced. In the nineteenth-century U.S., authors and citizens had competing social scales and identities, with the national subjective perceiving citizenship through racial, socioeconomic, and gendered identity markers. Regions become counternarratives to this construction; therefore, in those cultural spaces, authors often combat the perception of American citizenry as white middle-class, and male. The authors plot their criticisms through spatial movement within and between regions, as well as discussions of spatial transformations. For the second analysis, transregional approaches to American literature demonstrates the permeable boundaries of late nineteenth to early twentieth centuries literary genres. American authors crafted and experimented in various literary genres during the early postbellum decades. Genres that emerged during these formative years include realism, naturalism, and early experimentations with American modernism. Another literary experimentation—regionalism—begins as a hybrid genre that mixes antebellum romanticism and postbellum realist qualities. I concur with other literary critics that regionalism grants authorial space for minority and oppressed voices. In this way, regionalism allows authors to comment on American culture.
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    A Survey of Screen-Based Device Use by Public School Speech-Language Pathologists
    (2018-05) Sauermilch, Willow
    Limited information is present in the literature concerning the use of technology by speech-language pathologists (SLPs) during direct intervention. The present study addresses that gap by exploring (a) the frequency with which SLPs utilize eight types of screen-based devices during direct intervention, (b) rationales for screen-based device use, and (c) relationships between clinical factors and screen-based device use. The sample consisted of 261 public school SLPs across 43 states providing direct intervention services to students diagnosed with a communication disorder enrolled in preschool (n = 129), elementary (n = 202), secondary (n = 129), and post-secondary settings (n = 21). A purposive sample of respondents completed an internet-based self-administered survey reporting the frequency with which desktop computers, laptops, tablets, e-readers, handheld devices, interactive whiteboards, document cameras, and television, DVR, or DVDs were used. Among the eight types of screen-based devices surveyed, statistical analyses suggest that a majority of SLPs use tablets at a significantly higher rate of use, followed by laptops and handheld devices. Furthermore, results varied significantly when differentiated by student age, type of communication disorder, type of service delivery model, and years of professional experience. Caseload size and funding source did not significantly impact screen-based device use. The current study provides a pivotal step in exploring why and how SLPs utilize technology in a therapeutic manner.
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    Effect of a MetAP2 Inhibitor on Adipogenesis
    (2018-05) Siddik, Ad Abu Bakkar
    Obesity is one of the key factors in health related issues of our times and prevalence of obesity has nearly tripled since 1975. Angiogenesis is the process of blood vessel formation from endothelial cells or pre-existing vessels and closely associated with obesity or adipose tissue formation. So controlling angiogenesis can be a modulating factor for obesity. Methionine Amino Peptidase 2 (MetAP2) a metalloproteinase, has been shown be a regulatory element for angiogenesis and a target molecule for anti-angiogenic compounds. In our study we have investigated the effect of a MetAP2 inhibitor compound BL6 on adipogenesis. Our central hypothesis is that MetAP2 inhibitor BL6 will block adipogenesis in murine 3T3-L1 cells by blocking angiogenesis. Angiogenesis is also associated with tube formation of Human Umbilical Vein Endothelial Cells (HUVEC). Therefore, we also hypothesized that compound BL6 will also inhibit tube formation in HUVECs. Murine 3T3-L1 cells were treated with MetAP2 inhibitor compound BL6 (20µM, 50 µM and100µM) during differentiation with MDI cocktail. Cells were differentiated for 8 days followed by staining with Oil Red O to determine lipid accumulation. Protein and RNA was also extracted from these cells. Adiponectin, PPARγ, C/EBPα, C/EBP Beta, SREBP1 and FAS expression was quantified by Western Blot and RT-PCR. During in vitro differentiation of mouse 3T3-L1 preadipocytes, administration of 50μM and 100µM of BL6 resulted in reduced lipid accumulation (P<0.05). 100µM BL6 also resulted in decreased Adiponectin, PPAR γ, SREBP1 and FAS level though not significant. Surprisingly, elevated level of C/EBPα was observed inspite block to PPAR γ. Furthermore, cells treated with BL6 during the differentiation period maintained normal metabolic health and improved glucose uptake despite suppression of adipogenesis. Apart from block to adipogenesis, tube formation reduction in HUVECs was observed when administered with 20μM and 50μM of BL6. Collectively this proof of concept study supports the development of a MetAP2 inhibitor, BL6 as a putative therapeutic agent.
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    Species Distribution Modelling of Aedes aegypti and Aedes albopictus in the United States with an Emphasis on Current and Predicted Distribution in Texas
    (2018-05) Greenberg, Hannah S.
    Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus mosquitoes vector several pathogens of human health importance, namely chikungunya, dengue, yellow fever, and Zika virus. Though both mosquito species originally had tropical and subtropical ranges, they have been progressively reported from further poleward locations. Their augmented range increases the number of people at risk of being infected through these mosquito vectors. Local mosquito-borne transmission of Zika virus was first reported from Texas during November 2016, and is believed to be vectored only by Stegomyia spp. This study focused on two objectives, conducting surveillance for these mosquitoes throughout Texas, and to create and evaluate geospatial predictive models utilizing this data. Surveillance for gravid females of both species was conducted using ovitraps from August – November 2016 in 28 counties of the Texas Panhandle Region, and from June – October 2017 in 33 counties throughout Texas. Surveillance findings resulted in Ae. aegypti being newly identified in nine counties, while Ae. albopictus was newly identified in nine counties, and the occurrence of both species was newly identified in six counties. Maximum entropy modeling (MaxEnt) was used in R Statistical Software to estimate distributions for both species in the United States, and compared with the currently known ranges of these species in Texas specifically. Determining Ae. aegypti and Ae. albopictus species distributions in Texas and predicting their future species distributions in the United States using MaxEnt modeling could influence public health decision-making with the models used as tools to guide future practices.
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    Determining insecticide resistance of Stegomyia spp. in Texas
    (2018-05) Wilson-Fallon, Alexander N.
    Aedes (Stegomyia) aegypti and Aedes (Stegomyia) albopictus are known vectors of dengue, chikungunya, yellow fever, and Zika viruses. While source reduction is the primary method used to control these container-breeding mosquitoes, the difficulty in doing so makes insecticides the most feasible and effective control strategy. Reliance on chemical control has resulted in resistant mosquito populations globally, therefore decreasing the overall effectiveness of vector control operations and facilitating increased disease transmission. Insecticide resistance monitoring is a crucial tool that can identify developing mosquito resistance before it compromises control efforts. Monitoring for insecticide resistance is ideal in all entities with vector control capacity, however it is not always achievable due to financial and operational limitations. In the United States, insecticide resistance surveillance is limited and few published studies exist considering insecticide resistance in Stegomyia spp. The primary goals of this project were (1) to determine if Stegomyia spp. are resistant or becoming resistant to currently utilized insecticides by Texas vector control entities, and (2) to investigate and justify the use of male mosquitoes in laboratory-based insecticide resistance monitoring operations. My research revealed that (1) Stegomyia spp. in Texas counties have various levels of resistance to pyrethroids and organophosphates, (2) Ae. albopictus in Texas is more resistant to permethrin than malathion, (3) Ae. aegypti is more resistant than Ae. albopictus, and (4) there was no significant difference between male and female mortality in Ae. albopictus mosquitoes originating from Lubbock County.
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    Creation of Transgenic Cotton Overexpressing Salt Tolerant PP2A-C5 and Salt/Drought Tolerant AVP1
    (2018-05) Herath, Maheshika
    The United States is the third largest cotton producer in the world and Texas is the No. 1 cotton producer in the US responsible for ~30% of nation’s cotton production. In Texas High Plains, drought and saline soils are the major limiting factors that reduce quantity and quality of cotton fibers. Also, the excessive use of fertilizers results in salt accumulation in cotton lands. This is in part due to severe drought conditions in dryland agricultural systems. In some instances, lands are no longer suitable for cotton production. This research uses Agrobacterium-mediated plant transformation to co-overexpress PP2A-C5 and AVP1 in cotton in order to generate a cotton variety that can outperform conventional cotton varieties under dryland and irrigated agricultural systems. PP2A-C5 is the catalytic subunit 5 of Arabidopsisprotein phosphatase 2A. Arabidopsis thaliana plants overexpressing PP2A-C5 are more tolerant to high concentrations of NaCl, KCl, and KNO3. PP2A-C5 mediated multi-salt tolerance is possibly achieved via positive up-regulation of the chloride channel proteins localized on the vacuolar membrane, e.g. CLCa and CLCc, which import NO3- and Cl- ions into vacuoles, respectively, at the expense of protons. AVP1, a vacuolar membrane bound H+ pyrophosphatase acidifies the vacuole. Therefore, the overexpression of AVP1 provides ample H+ availability in the vacuole to energize chloride ion channels, further enhancing NO3- , K+, and Cl- uptake. It also activates other secondary transporters such as Na+/H+ antiporters, K+, NO3-, and inorganic PO43- transporters. As a result, the osmotic pressure of the vacuole is increased making the transgenic plants more drought- and salt-tolerant. Also, these plants will be more efficient in nitrate, phosphate, and potassium (NPK) absorption. Therefore, these transgenic plants will be expected to outperform AVP1-overexpressing and PP2A-C5-overexpressing cotton plants in terms of drought and salinity tolerance and fertilizer use efficiency.
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    Redox transformation of aqueous contaminants mediated by interfacial iron species
    (2018-05) Li, Yue
    Iron-containing mineral surfaces are of tnterest to environmental researchers because of their prevalent presence and significant activity in mediating contaminant transformation in the natural environment and engineered treatment systems. Despite the extensive research on bulk and single-phased iron oxides, the molecular iron species deposited on common mineral colloids, which is referred to as interfacial iron species in this dissertation work, have not yet been systematically examined for their reactivity in different aquatic systems. The overall objective of this dissertation is to examine the surface chemistry and reactivity of a range of iron-containing surfaces in catalyzing redox transformation of aqueous contaminants. This is achieved through investigations of several reactions systems: 1) the deposition of interfacial iron species on silica and alumina colloids and their activation of peroxide for oxidative transformation of organic carbon, 2) the interactions between arsenic and surface iron species arising during coagulation treatment and the role of the latter in catalyzing arsenite oxidation, 3) the activation of H2O2 and peroxydisulfate (persulfate) by two types of synthetic iron-containing catalysts for reactive oxidants generation. Multiple experimental methods were used in this dissertation work, including aqueous experimentation, spectrometric determination of aqueous constituents and advanced spectroscopic techniques including X-ray Electron Spectroscopy, Transmission Electron Microscopy. Results of this work provide several contributions. The study on activation of peroxide underlines the importance of interfacial iron species instead of iron oxide particles in contributing to catalytic oxidation of contaminants at the solid-water interface. The varying behaviors of Fe impregnated on the three types of mineral colloids reveal a strong impact of the support materials on iron species’ reactivity. Furthermore, coagulation process enhanced with Fe(II) or H2O2 amendment has pointed to the feasibility of tapping into the reactivity of in situ produced iron colloids as catalytic surfaces for more effective sequestration of pollutants such as aresenite. Since traditional coagulation treatment is widely applied in drinking water treatment plants, oxidative coagulation may provide a feasible option to small municipalities and rural communities to achieve arsenic compliance. Last but not the least, the investigations over the reactivity of synthetic iron-based materials conclude that iron-bearing xerogels represent a viable candidate of environmentally benign catalysts for peroxide-based oxidative treatment, while the incorporation of copper into spinel ferrite structure offers good catalytic activity in persulfate system.
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    Laser-Based Dual-Space Microscopy
    (2018-05) Alotaibi, Maged F.
    This dissertation numerically and experimentally implements Dual Space Microscopy (DSM)—a newly developed system for imaging objects in both the frequency and the real domain—using a laser as the illumination source. Results show that a highly coherent illumination source (like a laser) can be used to generate a high-resolution image of an object and to extend the field of view (FOV) in the object plane to a degree reversely proportional to the sizes of the diffraction orders present in the Fourier plane (FP) image. DSM and Fourier Ptychographic Microscopy (FPM), the other imaging system considered in this work, can overcome the physical limitation imposed by the microscope’s objective lens by combining synthetic aperture and phase retrieval techniques. Results also show that DSM can fully recover both the amplitude and phase information, which is inevitably lost during microscopic observation. Additionally, while DSM and FPM originally varied the angle of illumination of a single source, this dissertation numerically and experimentally implemented multiplexed illumination. The imaging system that resulted is termed “Illumination Direction Multiplexing Fourier Ptychographic Microscopy” (IDM–FPM). While IDM–FPM has been shown to reduce the acquisition time and the size of the data set required by orders of magnitude, it produces reconstructed images with high-resolutions. Finally, we investigate FPMs lateral resolution limit in imaging objects with spatial periodicities below the Rayleigh resolution limit. This work shows that FPM can indeed resolve the periodic features of photonic crystals well below the Rayleigh resolution limit. This result contradicts previous reports, which claimed that FPM cannot overcome the Rayleigh resolution limit in imaging photonic crystals.
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    Surface Modification of Commercial Zero Valent Iron (ZVI) for Degradation of Chlorinated Ethenes
    (2018-05) Islam, A.S.M. Syful
    It has been shown in several recent studies that sulfidation enhances the reactivity of nanoscale zero-valent iron (nZVI) for dechlorination of chlorinated ethenes. The majority of these studies have been carried out using lab synthesized nZVI particles via borohydride reduction method. Sulfidation of commercially available zero valent iron (ZVI) has scarcely been studied. Given the widespread application of commercial ZVI products (e.g., ZVI granules, filings or powder) in remediation field installations, the use of sulfidation to enhance the reactivity of commercial ZVI in degrading chlorinated contaminants is of growing interest to remediation researchers and practitioners. To address this necessity, the effects of sulfidation on dechlorination performance of five different commercial ZVI particles were assessed using trichloroethene (TCE), tetrachloroethene (PCE), and cis-1,2-dicchloroethene (cis-DCE) as model contaminants. Alfa Aesar iron powder (spherical, <10 micron, 99.9+% (metals basis)), BASF Carbonyl Iron Powder (CIP) OM and CC grade, HEPURE Ferox-PRBTM zero valent cast iron powder, and Peerless zero valent cast iron were employed in this study. They were referred to as AA, B-OM, B-CC, HPR, and PLES, respectively. Sulfidation of ZVI was done either by soaking particles in sulfur precursor solutions (referred to as “direct sulfidation”), or by pre-washing the particles in diluted hydrochloric or acetic acid before mixing with sulfur precursor solutions (referred to as “sulfidation”). Sodium thiosulfate was used to prepare sulfur precursor solutions, and S/Fe molar ratio was fixed at 0.05 for all the batch experiments. As a control, as-received ZVI materials or those washed in acid solutions without further exposure to sulfur amendments were prepared as well. The chemically treated ZVI particles were reacted with model contaminants in batch reactors with headspace. The headspace of the batch reactors was sampled periodically to quantify parent compounds, reaction intermediates, and products. Results of the batch experiments indicated that sulfidation of commercial ZVI significantly enhanced TCE reduction rates compared to the respective as-received ZVI products (i.e., no acid washing and/or sulfidation treatments). The apparent mass normalized pseudo-first-order TCE degradation rate constants of sulfided AA, B-CC, HPR, and PLES ZVI particles were 1.77, 1.02, 0.682, and 6.29 x 10-5 L/g-min respectively, which were 53.2, 54.3, 4.6, and 118 folds higher respectively than that of the untreated particles. TCE reduction rate constant for B-OM was 2.39 10-5 L/g-min, which was 1.9 folds higher compared to direct sulfidation. TCE degradation by all five ZVI yielded similar products including ethene and ethane as dominant products. No chlorinated intermediate was detected, except that very small amount of cis-DCE was detected during TCE degradation by sulfided and direct sulfided B-OM, and sulfided AA particles. Compared to significant improvements in TCE dechlorination rates, PCE and cis-DCE dechlorination rates were enhanced to smaller extents by the sulfidation of commercial ZVI used in this study. Mass normalized pseudo-first-order PCE degradation rate constants of sulfided AA, B-OM, and HPR ZVI particles were 2.74, 1.65, and 2.46 x 10-6 L/g-min, respectively, and cis-DCE degradation rate constant of sulfided AA, B-OM, and HPR ZVI particles were 1.33, 0.76, and 0.21 x 10-6 L/g-min, respectively. In the last part of this study, the effect of metal impurities on ZVI reactivity for the degradation of PCE and cis-DCE was also evaluated. Experimental results showed that copper amended particles enabled higher degradation rates for both PCE and cis-DCE compare to unamended ZVI. Nickel amended ZVI increased PCE removal rate, but was ineffective for cis-DCE. Manganese amendment did not show any improvement in removal of either PCE or cis-DCE. Lastly, sulfidation was conducted on Cu-amended B-OM ZVI for PCE degradation. Data revealed that sulfur is able to poison the catalytic effect of Cu and significantly slow down PCE reduction. Therefore, the effect of sulfidation on reactivity of commercial ZVI is selective to the type of contaminants and importantly, depends on their chemical compositions and nature of impurities, which are strongly affected by their manufacturing routes.
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    Characterization of Agronomic and Physical Traits of HI-A Corn Hybrids of the Texas High Plains
    (2018-05) Vavra, Cody J.
    Corn (Zea mays) in terms of production ranks first for the amount of land cultivated every year in the world (Awika, 2011). In the Texas High Plains, corn is one of the major crops grown in this region and accounts for 41% of total irrigated crop water use (Colaizzi et al., 2008). In this region of Texas, we’re seeing a growing interest in developing corn hybrids that are high-yielding, have quality agronomic performance, and can adapt to the fluctuating environments of the Texas High Plains. In this study, we evaluated the potential commercial value of seventeen experimental corn hybrids that have been developed by Texas A&M AgriLife Corn Breeding Program in Lubbock. Majority of these hybrids have a high natural accumulation of anthocyanin (HI-A trait) within the plant tissues. The hybrids with the HI-A traits were termed “HI-A hybrids”. The objective of this study was to characterize the HI-A hybrids for grain yield and agronomic traits to determine the effect of genetic background and environments on the expression of the HI-A trait; and to develop a high throughput method for quantitative measurement of the cob strength of HI-A hybrid cobs. The 17 experimental hybrids along with three commercial checks were evaluated in 2016 and 2017 under well-watered and post-tassel drought stress conditions in Lubbock, TX and under limited-irrigation conditions in Halfway, TX. The HI-A hybrids between the five stiff-stalk HI-A lines B5C2RMA, B5C2RMB, B5C2RMC, B5C2RMD, B5C2RME with non-still stalk lines HBA1, LH123HT, LH150, NS1, PHJ31, PHJ65, PHN82, and PHV78 yielded comparably or higher than the commercial hybrids. They have the potential use for direct commercial production for grain, silage, and/or potentially special chemical compounds.
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    The Effect of Clawback on Managerial Use of Expectations Management and Market Consequences
    (2018-05) Guo, Savannah (Yuanyuan)
    Since 2007, voluntary adoption of compensation Clawback provisions has grown prevalent among U.S. listed firms. By 2014, approximately 50% of Russell 3000 firms had adopted such policies. Clawback provisions allow adopting firms to recoup incentive-based compensation paid to executives if misstatements in prior financial reports are later discovered. Researchers assert that Clawbacks could impose unintended consequences on adopting firms. I contribute to this argument by providing empirical evidence that Clawback firms are more likely to issue downward earnings guidance to lower analysts-set earnings goals. This is consistent with the notion that Clawback adoptions encourage managers to use methods other than accruals management to achieve earnings goals without risking triggering a Clawback. I also find a significantly weaker market reaction to downward guidance issuance and earnings surprises announcements post-Clawback. These results are robust to controlling for the decision to adopt a Clawback provision voluntarily. Overall, my findings suggest that although the stock market provides less pressure to meet earnings goals post-Clawback, opportunistic managers continue to fixate on playing the “numbers game” and they do so by managing analyst expectations.
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    Brass Quintet Tuning: A New Method To Promote Ensemble Intonation
    (2018-05) Young, Kevin
    Brass Quintet Tuning: A New Method To Promote Ensemble Intonation is written for brass quintets to assist in improving an ensemble’s intonation. This document consists of an insight into the Just Intonation (JI) process of tuning to include a background on the construction of scale intervals. Additionally, the author provides practical methods and a chart of intonation deviations which ensembles can use to help with tuning. This paper culminates in laying the groundwork of a method book of tuning exercises for brass quintets. The author has found some ensembles sound different, in fact better, in terms of their intonation, and it is more than just “matching pitch”. Using Just Intonation intervals will result in better sounding ensemble intonation once ensembles can train their ears to hear these intervals and place them appropriately. Since there are few exercises available to help brass quintets train to hear and play these JI intervals, the author has provided thirty exercises for brass quintets to assist with this process.
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    Investigations into the Fate and Occurrence of Chlorate in the Environment: Implications for Oxy-Chlorine Species on Mars and Earth
    (2018-05) Brundrett, Maeghan
    ClO3- occurrence, production, and post depositional transformation has significant implications to our understanding of chlorine (Cl) cycling and potential biogeochemical reactions on Earth and Mars. However, little information is known on the natural isotopic composition of ClO3- and the post-depositional processes that can reduce ClO3- in the environment. The objective of this study was to develop a method to measure the stable isotope composition (δ18O, δ17O and δ37Cl) of ClO3- and to determine the isotopic composition of ClO3- in natural desert salt accumulations that have been studied previously for NO3- and ClO4-. We also determine the potential abiotic transformation of ClO3- by Fe (II)-bearing minerals, similar to known reactions between NO3- and Fe (II) minerals. Additionally, ClO3-, nitrate (NO3-), and ClO4- were evaluated for use as electron acceptors in comparison to oxygen (O2) by comparing oil transformation and mineralization in mesocosms consisting of oiled salt marsh sediment from an area impacted by the BP Horizon oil spill. The isotopic composition of oxyanions can be used to evaluate their production mechanisms and post-depositional alteration. The process of ClO3- purification and analysis of δ18O, δ 17O and δ37Cl is problematic, but has recently been resolved by adapting previously published methods for ClO4-. Competitive anions (e.g. NO3-, Cl-, ClO4-, and SO4-2) are removed through a series of processes including biological reduction, solid phase extraction, and anion or cation exchange and for the first time we report the natural isotopic composition of ClO3- from Death Valley and the Atacama Desert. As the presence of iron-derived minerals has been established in Antarctica, Martian soils, and chondrite meteorites, batch experiments were conducted by reacting four Fe (II)-bearing minerals (wustite, siderite, magnetite, and green rust) with ClO3- at various pH (4.5, 6.5, 8.9). Chlorate reduction was rapid and generally ClO3- was quantitatively converted to Cl-, establishing a previously unknown abiotic reaction that could reduce ClO3-. In order to determine the potential biotic reduction of oxy-anions during oil transformation, mineralization rates were determined by measuring CO2 production and δ13C of the produced CO2 and compared to transformation evaluated by measuring the alkane/hopane ratios over a 4 month period. Oil mineralization was greatest for the aerated treatments and least for the perchlorate amended. Results of this study will increase our understanding of production and surface reactions that produce and transform oxy-chlorine compounds.
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    Arbiters of Identity: Remembering the American Revolution through Early Nineteenth Century Schoolbooks
    (2018-05) Slavin, Courtney E.
    In this thesis, I examine how the early Americans formed a united national identity through the memory of the American Revolution that was widely accepted on behalf of the publication of early American schoolbooks. These historical narratives, promoted by early schoolbook authors, were intentionally modified in order to create an ideal historical memory for the purpose of instilling a national patriotism and morale. I argue that the collective effort of the schoolbook authors was successful in creating a nationally accepted identity by manufacturing the Revolution as unique and exemplary, but also personal and intimately experienced by all of those within the United States, whose perceived superiority was only further reinforced by placing it in comparison to other dignified countries that ultimately fell short of the American paradigm. This thesis makes extensive use of the Nietz Collection held at the Hillman Library at the University of Pittsburgh, a collection that houses 20,000 volumes of nineteenth century schoolbooks. The majority of the texts I studied, which were published between the 1790s and 1840s, endured long after their first publication. Many earning thirtieth, fortieth, and fiftieth edition publications often with little to no revision, only subsequent chapters tacked onto the end to keep it current. Thus, these juvenile texts carried excessive cultural weight in defining what was American for multiple generations long after the Revolutionary generation had passed.
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    Essays on Fiscal and Monetary Policy with Informational Frictions
    (2018-05) Dogruer, Funda E.
    This dissertation examines the effects of informational frictions on fiscal and monetary policies. The first chapter explores optimal fiscal and monetary policy with sticky information in the production sector. Labor income tax rate smoothing over the business cycle is a key result in the optimal fiscal policy literature. This first chapter studies the optimality of tax smoothing in a model with sticky information in the production sector, and compares the dynamic responses of the economy to government spending and technology shocks under both sticky information and sticky prices. The main finding of first chapter is that the introduction of information stickiness causes large fluctuations in the labor income tax rate even if prices are fully flexible; therefore, full smoothing of the labor income tax rate is not optimal. On the other hand, when the degree of information stickiness increases, the volatility of inflation declines. These findings reflect the observation that, in the sticky information model, the cost of obtaining and processing the information makes firms inattentive, which in turn induces stickiness in the behavior of inflation. I also show that a government spending shock generates less volatility in the main variables under sticky information than in sticky price model. In the second chapter, I study monetary policy rules in the presence of fiscal uncertainty. I develop a model with informational frictions on the government spending in the context of dynamic stochastic general equilibrium (DSGE) framework and investigate its implications for economic dynamics and monetary policy rules. The effects of government spending shock and noise shock on the selected macroeconomic variables were compared under three monetary policy rules: Taylor rule, strong response to inflation rule and inflation targeting rule. I find that persistency of the government spending shock long lasting more than noise shock under Taylor rule, because it is a real and more anticipated shock. On the other hand, noise shock takes shorter time for agents to realize that it is just a noise and lasts no longer. The results show that selected macroeconomic variables under three policy rules behave similarly to noise shock and government spending shock. It is also determined that the inflation targeting rule generates the most desirable results and plays a successful role in stabilizing the economy.
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    Real-Time Simulation of Fluid Flow Based on Sensor Data Using ODE Constrained Optimization
    (2018-05) Rush, Simon
    A growing idea in the field of wind energy research is the concept of wake steering. Wake steering is the idea that by controlling the placement of the wake away from subsequent rows of turbines, an overall net increase in power production can be achieved by a wind farm. However, in order steer the wake, one must first know where it is, or short of that, have a reliable numerical method for determining its location. At the time of this publication, full Computation Fluid Dynamics (CFD) simulations for fluid flows are too expensive in order to achieve an approximation that could be used in relevant decision making; i.e. using the fluid flow approximation as part of a steering strategy. The purpose of this work is to aid this field of research by developing a method for simulating a fluid flow approximation based off of sensor data in real-time. Once the approximation to the flow is achieved, numerous techniques can be applied to determine the location of the wake. In order to achieve this approximation, we will utilize the theory of Reduced-Order Modeling (ROM). To achieve a ROM, we will need to derive appropriate basis and coefficient functions. The basis functions our ROM will rely on will be calculated using a Proper Orthogonal Decomposition (POD). This methodology requires a library of fluid data collected from the span of desired parameters that the ROM will be considered reliable for. This data will be supplied via Viento, a CFD simulator we developed during the course of our research. The generation of these basis functions will occur outside of the time-sensitive context of creating the approximation. To determine the time-dependent coefficient functions two methods will be considered: solving the reduced-order forward problem as a type of benchmark and solving the Karush-Kuhn-Tucker (KKT) system generated from an Ordinary Different Equation (ODE) constrained-optimization problem. It is the second-type, in which we minimize the difference between the values produced by the approximation and the available sensor data, that we are proposing be used to generate fluid flow approximations in real-time.
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    Investigating the Impact of Professional Development of Global STEM Education on Teacher Self-efficacy and Instructional Practice: A Multiple Case Study
    (2018-05) Wiggs, Beth A.
    This multiple case study examined three elementary school teachers from a large suburban school district in Texas that engaged in a professional development program centered on global STEM education. The focus was on understanding how learning during professional development for global STEM education impacted teacher’s change in self-efficacy, practice, and also examined factors related to teacher’s perceptions of global STEM education practices. This study explores changes in beliefs, self-efficacy, and practice with global STEM over the course of a four month period. The research was viewed through a conceptual framework adapted from Desimone’s work on professional development. The research design utilized multiple data collection techniques including surveys, interviews, observations, and document analysis. Each of the three single case studies findings were reported separately for an understanding of teachers’ perceived self-efficacy and practice, and the findings from these cases were aggregated across the three case studies to answer the research questions. Findings from this study suggest that while two of the teachers changed their beliefs of self-efficacy in STEM and all three implemented STEM practices in the classroom, they did not apply global practices with STEM. This indicated a gap between professional development theory and self-efficacy and practice. An implication of the study’s findings includes a focus on teacher collaboration within grade levels or campus bands to share ideas about global STEM education.
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    On Mixed Variational Large Deformation Theories for Corrections of Classical von Kármán Theory of Thin Plates
    (2018-05) Lassmann, James
    For thin plates, linear deformation theory is only valid, when the plate deformation is on the order of the thickness of the plate. To ensure validity of results for larger deformations, geometrically non-linear strains must be used to properly reflect the behavior of the plates deformations. One of the earliest and most widely known non-linear plate theories is von Kármán thin plate theory, which was proposed by Theodore von Kármán in 1910. This thesis reexamines the classical von Kármán thin plate theory and seeks to re-formulate the governing equilibrium equations for thin plates undergoing large geometrically nonlinear deformations in terms of the plate displacements, using the Hu-Washizu mixed field variational statement. Additionally, other mixed field and single field variational statements are examined for the same purpose in order to determine any differences between them. Governing equilibrium equations yielded from each variational statement are compared to examine differences in the terms obtained. Those governing equilibrium equations will then be compared against existing formulations for the governing equilibrium equations for von Kármán thin plate theory, and their solutions found for the cases of statically loaded simply supported, statically loaded clamped plates, and simply supported free and forced vibrations to assess the validity of the governing equilibrium equations derived. Improvements to the formulation of thin plate theory allows for improvements to the design process of ship hulls, aircraft skins, and automobile bodies that incorporate thin plates. Improvements to accurate modeling of thin plates, could lead to reductions in the weight and cost of systems that use thin plates.
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    Mindfulness for Science and Math Special Education Teachers: Perceived Value in Coping with Stress and Burnout
    (2018-05) Cao, Carol A.
    As education shifts to focus more on science, technology, engineering, and math (STEM) skills and 21st century skills, special education (SpEd) teachers are facing more challenges in the classroom to meet the needs of students with disabilities and to prepare their students for a global economy. These challenges add to the pressure and stress SpEd teachers encounter in the classroom. When the needs of teachers are not met, stress increases, leading to teacher burnout. Teacher burnout contributes to the high attrition rates and issues with teacher retention in SpEd. Without highly qualified teachers, the needs of students cannot be met. Schools and districts need to look at ways to help teachers cope with the challenges they face in the classroom. Mindfulness-based practices are one viable method to provide teachers with the tools and skills needed to alleviate feelings of burnout. This qualitative research study looked at five science and math special education (SpEd) teachers as they engaged in an eight-week long mindfulness-based practices training program. Data collected explored challenges participants face in science and math SpEd classroom that contribute to teacher burnout. In addition, data collected examined participants’ conceptual understanding of mindfulness and perceived value of a mindfulness-based practices training to address attrition and retention issues within SpEd. To better understand how participants perceived the value of mindfulness-based practices as viable tools and skills to cope with the challenges in the science and math SpEd classroom, to alleviate stress and burnout, and to build social and emotional competence (SEC), pre- and post-training interviews, reflective journals, and classroom observations. Findings suggested that participants developed a more comprehensive understanding of mindfulness and gained mindfulness skills (awareness, attention, autonomy, belonging and competency). These skills translated into the classroom and into participants’ personal lives. Perceived value in mindfulness-based practices related to the classroom included improved relationships with students, better management of student behaviors, improved classroom environment, better stress management, better ability to cope with the dimensions of burnout (emotional exhaustion, depersonalization, and lack of personal accomplishment), improved understanding of personal and students’ emotions, being less reactive, and connecting more with students. In their personal lives, participants noted that mindfulness-based practices positively affected their relationships with their children and help them stay more in the moment outside of the profession. However, participants expressed challenges with time and consistency with daily practice. Though all participants had overall positive experiences in the mindfulness-based practices training, they also noted the need for more trainings over a longer period of time and the need to start trainings at the beginning of the school year. Thus, it is important to take into consideration the needs of and recommendations from teachers in planning a future mindfulness-based practices training, as a viable means to address challenges in the classroom and teacher burnout.
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    Three essays in corporate finance
    (2018-05) Niu, Xu
    This dissertation consists of three essays in corporate finance. The first essay examines whether founder family successions lower performance in large US firms. I find no significant drops, and often positive changes, in performance or value associated with founder family successions. The second essay studies the role of founder-CEOs and founder-families in IPOs. This paper shows that, in large US companies, founder-CEO and founder-family controlled firms experience about 10% more underpricing relative to non-founder firms during the IPO process. Moreover, this paper shows that the partial adjustment phenomenon is weaker for firms that are controlled by founder-CEOs at the time of IPOs, supporting Loughran and Ritter's (2002) prospect theory explanation on this effect. The third essay studies the relation between strategic voting and insider ownership. This paper outlines a model of strategic shareholder voting that allows outside shareholders to mitigate the influence of insiders. Consistent with the model, I find empirical support for strategic voting by outside shareholders and that strategic voting is more apparent when management-sponsored proposals are controversial or when other agency risks are greater.