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Title: Investigating the relationship between uv-b radiation exposure and racial disparities in preeclampsia : a medical geography study
Creator: Kutch, Libbey C.
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Preeclampsia is the leading cause of morbidity and mortality in the United States. Research had demonstrated that adequate levels of vitamin D can help to circumvent the risk of preeclampsia. Vitamin D plays a role in cardiovascular health and in maternal health, and cutaneous exposure to ultra-violet (UV)-B radiation is critical to maintaining healthy vitamin D levels. The majority of vitamin D in humans is produced when the skin is exposed to ultraviolet radiation. UV-B varies...
Show morePreeclampsia is the leading cause of morbidity and mortality in the United States. Research had demonstrated that adequate levels of vitamin D can help to circumvent the risk of preeclampsia. Vitamin D plays a role in cardiovascular health and in maternal health, and cutaneous exposure to ultra-violet (UV)-B radiation is critical to maintaining healthy vitamin D levels. The majority of vitamin D in humans is produced when the skin is exposed to ultraviolet radiation. UV-B varies geographically; therefore geography influences the availability of vitamin D and the potential risk for preeclampsia. However, research on the geographic relationship between UV-B and pregnancy induced hypertensive disorders, including preeclampsia has been relatively neglected. This research investigates the relationship between maternal UV-B exposure and preeclampsia for mothers giving birth in Michigan from 2008 to 2015 during 3 time periods, 1-pre-conception, 2-early pregnancy, and 3-late pregnancy. A medical geographic and human ecological framework conceptualizes the environmental, biological and behavioral factors influencing the UV-B and preeclampsia relationship. UV-B is estimated using the Erythemal Daily Dose calculated form OMI remote sensing data. Preeclampsia is measured using Michigan's Vital Statistics Birth Data 2008-2015. Multilevel models were estimated to study these relationships. This study found that slight increases in UV-B exposure prior to conception and later in pregnancy could reduce the odds of preeclampsia for white but not black mothers. Other important risk factors for preeclampsia were increasing BMI, chronic and gestational diabetes and living in urban areas. Receiving Medicaid was protective for preeclampsia for white mothers but not black mothers. Enrollment in WIC was highly protective for all mothers. This medical geography research demonstrates the importance of utilizing remote sensing to begin to understand UV-B exposure on an important pregnancy outcome from a population perspective. Future research should also focus on reevaluating the measurement of the Erythemal Daily Dose to reflect people with high melanin concentrations. Future research could also branch out to other highly prevalent conditions with low vitamin D susceptibility such as cancers and dementia and Alzheimer's.
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Title: A container-attachable inertial sensor for real-time hydration tracking
Creator: Griffith, Henry
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The underconsumption of fluid is associated with multiple adverse health outcomes, including reduced cognitive function, obesity, and cancer. To aid individuals in maintaining adequate hydration, numerous sensing architectures for tracking fluid intake have been proposed. Amongst the various approaches considered, container-attachable inertial sensors offer a non-wearable solution capable of estimating aggregate consumption across multiple drinking containers. The research described herein...
Show moreThe underconsumption of fluid is associated with multiple adverse health outcomes, including reduced cognitive function, obesity, and cancer. To aid individuals in maintaining adequate hydration, numerous sensing architectures for tracking fluid intake have been proposed. Amongst the various approaches considered, container-attachable inertial sensors offer a non-wearable solution capable of estimating aggregate consumption across multiple drinking containers. The research described herein demonstrates techniques for improving the performance of these devices.A novel sip detection algorithm designed to accommodate the variable duration and sparse occurrence of drinking events is presented at the beginning of this dissertation. The proposed technique identifies drinks using a two-stage segmentation and classification framework. Segmentation is performed using a dynamic partitioning algorithm which spots the characteristic inclination pattern of the container during drinking. Candidate drinks are then distinguished from handling activities with similar motion patterns using a support vector machine classifier. The algorithm is demonstrated to improve true positive detection rate from 75.1% to 98.8% versus a benchmark approach employing static segmentation. Multiple strategies for improving drink volume estimation performance are demonstrated in the latter portion of this dissertation. Proposed techniques are verified through a large-scale data collection consisting of 1,908 drinks consumed by 84 individuals over 159 trials. Support vector machine regression models are shown to improve per-drink estimation accuracy versus the prior state-of-the-art for a single inertial sensor, with mean absolute percentage error reduced by 11.1%. Aggregate consumption accuracy is also improved versus previously reported results for a container-attachable device.An approach for computing aggregate consumption using fill level estimates is also demonstrated. Fill level estimates are shown to exhibit superior accuracy with reduced inter-subject variance versus volume models. A heuristic fusion technique for further improving these estimates is also introduced herein. Heuristic fusion is shown to reduce root mean square error versus direct estimates by over 30%. The dissertation concludes by demonstrating the ability of the sensor to operate across multiple containers.
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Title: The impact of bt crops on aflatoxin reduction
Creator: Yu, Jina
Date: 2019
Collection: Electronic Theses & Dissertations
Description: This dissertation is about how adoption of a genetically engineered plant works as a prevention method for aflatoxin, a carcinogen that commonly contaminates food crops such as corn and peanuts interacting with climate condition. First produced in the United States in 1996, Bt corn has become one of the most commonly grown transgenic crops worldwide. Aside from improving corn growers' yields, it has also resulted in an 11% decrease in insecticide use on US corn. Multiple experimental studies...
Show moreThis dissertation is about how adoption of a genetically engineered plant works as a prevention method for aflatoxin, a carcinogen that commonly contaminates food crops such as corn and peanuts interacting with climate condition. First produced in the United States in 1996, Bt corn has become one of the most commonly grown transgenic crops worldwide. Aside from improving corn growers' yields, it has also resulted in an 11% decrease in insecticide use on US corn. Multiple experimental studies found that the level of aflatoxin, a fungal toxin, can be mitigated by reducing the presence of insects because fungi colonize corn through kernel wounds from insect feeding. However, the relationship between Bt corn and aflatoxin has yet to be examined in field settings, wherein many environmental factors are at play. Given the higher environmental risks of temperature and drought, revealing the mechanism by which Bt corn reduces aflatoxin can inform farmers' decision-making on crop choices and seed choices.In the first essay, I developed a regression model that estimates causal relationships between aflatoxin-related insurance claims and Bt corn adoption rates, drought index, and climatic variables. From 2001-2016, a significant inverse correlation existed between Bt corn planting and aflatoxin-related insurance claims in the United States when controlling for temperature, drought, state, and year. Estimated benefits of Bt corn's aflatoxin reduction were about $120 million to $229 million per year in over 16 states on average. These results suggest that Bt corn is an important strategy with corresponding economic benefits for reducing aflatoxin risk in the United States. Climate change-typically increased temperature-may expand prevalence zones for aflatoxin because warm temperatures and dry conditions are associated with aflatoxin accumulation. The second essay's objectives were to predict both areas with high aflatoxin risks in 2031-2040 based on 16 climate models, as well as the extent of aflatoxin-related economic loss due climate change. To do so, growing season impacts on aflatoxin risk were modeled by allowing for the adjustment of planting season under different climate scenarios. It was found that more than 89% of corn planting areas are likely to experience increased aflatoxin risks in 2031-2040 when compared to aflatoxin risks from 2007-2016 in the United States. Ignoring health-related costs, aflatoxin-related economic loss was expected to amount to $36 million - $70 million per year.In the third essay, I examined an additional potential benefit of Bt crops (corn and cotton): a decrease in the incidence of aflatoxin in peanuts (non-Bt crops). Bt crops can help reduce aflatoxin levels by reducing insect damage, a key path of fungal infection. However, the effect of Bt crops should not be limited to the adopted crops, because insects controlled by Bt have a relationship with other crops and insects in the broader ecosystem. Furthermore, the sales of aflatoxin-contaminated peanuts are currently under regulation. As such, the negative relationship between Bt and aflatoxin in peanuts means that Bt crops can also provide a meaningful, unintended economic benefit to peanut farmers by reducing aflatoxin. In addition to the Bt crops, temperature and drought at key stages of peanut growth were included as potential confounding factors in aflatoxin-related insurance claims. The results indicate that a county with a higher Bt crops adoption rate was less likely to have aflatoxin-related insurance claims in peanuts. This means that, by reducing the incidence of aflatoxin, Bt crops adoption in the United States has saved losses of $0.45 million per year. Overall, my dissertation study increases current understandings of the unintended effects of Bt in protecting crops from aflatoxin damage in the broader ecosystem. It aims to shed light on the benefits of Bt crops in countries that suffer from aflatoxin-related damage and transgenic seed traits that are not planted. Additionally, this study contributes to improved knowledge about climate conditions that affect either aflatoxin levels or host plants (corn and peanut). As climate change is expected to increase temperature and dryness, it is likely to increase the risk of aflatoxin in the US. Bt crops and new biotechnology are thus expected to play an important role in protecting crops from aflatoxin damage.
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Title: Molecular dynamics and continuum simulations of fluid flows with slip boundary conditions
Creator: Niavaranikheiri, Anoosheh
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Microfluidics is a rapidly developing field with applicationsranging from molecular biology, environmental monitoring, andclinical diagnostics. Microfluidic systems are characterized bylarge surface-to-volume ratios, and, therefore, fluid flows aresignificantly influenced by boundary conditions. The fundamentalassumption in fluid mechanics is the no-slip boundary condition,which states that the tangential fluid velocity is equal to theadjacent wall speed. Although this assumption is...
Show moreMicrofluidics is a rapidly developing field with applicationsranging from molecular biology, environmental monitoring, andclinical diagnostics. Microfluidic systems are characterized bylarge surface-to-volume ratios, and, therefore, fluid flows aresignificantly influenced by boundary conditions. The fundamentalassumption in fluid mechanics is the no-slip boundary condition,which states that the tangential fluid velocity is equal to theadjacent wall speed. Although this assumption is successful indescribing fluid flows on macroscopic length scales, recentexperimental and numerical studies have shown that it breaks down atmicroscopic scales due to the possibility of slip of the fluidrelative to the wall. The effect of slip is more pronounced forhighly viscous liquids like polymer melts or in the region near themoving contact line due to the large gradient in shear stress at theliquid/solid interface. The measure of slip is the so-called sliplength, which is defined as a distance between the real interfaceand imaginary plane where the extrapolated velocity profilevanishes. The slip length value is sensitive to several keyparameters, such as surface energy, surface roughness, fluidstructure, and shear rate.In this dissertation, the slip phenomena in thin liquid filmsconfined by either flat or structured surfaces are investigated bymolecular dynamics (MD) and continuum simulations. It is found thatfor flows of both monatomic and polymeric fluids over smoothsurfaces, the slip length depends nonlinearly on shear rate atsufficiently high rates. The laminar flow away from a curvedboundary is usually described by means of the effective slip length,which is defined with respect to the mean roughness height. MDsimulations show that for corrugated surfaces with wavelength largerthan the size of polymer chains, the effective slip length decreasesmonotonically with increasing corrugation amplitude. A detailedcomparison between the solution of the Navier-Stokes equation withthe local rate-dependent slip condition and results of MDsimulations indicates that there is excellent agreement between thevelocity profiles and the effective slip lengths at low shear rateand small-scale surface roughness. It was found that the main causeof the slight discrepancy between MD and continuum results at highshear rates is the reduction of the local slip length in the higherpressure regions where the boundary slope becomes relatively largewith respect to the mainstream flow. It was further shown that forthe Stokes flow with the local no-slip boundary condition, theeffective slip length decreases with increasing corrugationamplitude and a flow circulation is developed in sufficiently deepgrooves. Analysis of a numerical solution of the Navier-Stokesequation with the local slip condition shows that the inertialeffects promote the asymmetric vortex flow formation and reduce theeffective slip length.
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Title: A comparative investigation of two barn trusses
Creator: Wright, R. E.
Date: 1942
Collection: Electronic Theses & Dissertations

Title: Jesus People USA, the Christian Woodstock, and conflicting worlds : political, theological, and musical evolution, 1972-2010
Creator: Young, Shawn David
Date: 2011
Collection: Electronic Theses & Dissertations
Description: This study is an analysis of an evangelical commune located in Chicago's inner city. Self-described as an "intentional community," Jesus People USA (JPUSA) is one of the remaining collective expressions of the Jesus Movement, an American revival that occurred during the 1960s and 1970s. After considering the reasons for this commune's longevity, I make three core arguments. First, the study of communes in American history shows that in most cases, American communes are often short-lived....
Show moreThis study is an analysis of an evangelical commune located in Chicago's inner city. Self-described as an "intentional community," Jesus People USA (JPUSA) is one of the remaining collective expressions of the Jesus Movement, an American revival that occurred during the 1960s and 1970s. After considering the reasons for this commune's longevity, I make three core arguments. First, the study of communes in American history shows that in most cases, American communes are often short-lived. JPUSA has continued beyond its 1972 genesis due to various structural mechanisms and an ability to engage and evolve with American culture. The fact that JPUSA has survived to the present can be attributed to what sociologist Rosabeth Moss Kanter refers to as "commitment mechanisms." However, an analysis of commitment levels among second-generation communards demonstrates that these mechanisms are often problematic. Moreover, longevity will be determined by how the commune is perceived by the evangelical subculture as the commune evolves ideologically. Second, musical subgenres such as Christian heavy metal and punk rock would not have grown in influence if not for the Cornerstone Festival. Furthermore, JPUSA and their festival have challenged mainstream contemporary Christian music (CCM) and redefined the way evangelical popular music is commonly understood. In a sense, the commune and the festival have ruptured conventional understandings of "sacred" and "secular." Third, JPUSA's evolution demonstrates how a group committed to certain ideologies can change as a result of pluralism. Thus this community serves as one case-study in howAmerican evangelical groups must reinvent their collective ethos and re-categorize their cultural products if they are to remain relevant. In so doing, JPUSA's presence challenges "establishment evangelicalism" and problematizes conventional understandings of the classifier "evangelical." JPUSA's commitment to social justice and emphasis on humanizing the Christian gospel (without fully redefining conventional understandings of human salvation) places them in a category best understood as "Evangelical Left."
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Title: Correlation of point defects in lithium-rich layered cathode materials for lithium-ion battery applications
Creator: James, Christine Nicole
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The limiting component of lithium-ion batteries continues to be the cathode component. Since the layered materials, such as LiCoO2, have observed capacities of roughly half of their theoretical capacities, advances have been made in attempts to improve their stability and thus capacity. One such attempt is adding Li2MnO3, thus creating Li2MnO3-LiMO2 materials, where M is typically a transition metal ion or combination of transition metals. These Li2MnO3 stabilized materials have been shown to...
Show moreThe limiting component of lithium-ion batteries continues to be the cathode component. Since the layered materials, such as LiCoO2, have observed capacities of roughly half of their theoretical capacities, advances have been made in attempts to improve their stability and thus capacity. One such attempt is adding Li2MnO3, thus creating Li2MnO3-LiMO2 materials, where M is typically a transition metal ion or combination of transition metals. These Li2MnO3 stabilized materials have been shown to be promising with >200mAh/g but still suffer from performance issues. The Li2MnO3 component is observed to lose oxygen during the first charge cycle and thus creates Li2-XMnO3-δ. These oxygen vacancies are related to some of the cathode performance issues. However, the amount of oxygen released and the role of the oxygen vacancies are still not very well understood. Therefore, this work takes an atomic level computational approach using density functional theory calculations to explore the impact of oxygen vacancies and the correlated effects on voltage, capacity, lithium diffusion, chemical strain, dopants and electrolyte decomposition. Despite the extensive computational work in the literature on lithium transition metal oxide cathode materials, little work has been devoted to the correlated effects of two vacancy types in these materials. Therefore, this work offers novel approaches to model both vacancy types and their impacts on each other. First, it was found that the oxygen vacancies can decrease the formation energy of lithium vacancies. Less hopping of lithium atoms is observed and the energy barrier for lithium hopping is increased when oxygen vacancies are present. The calculated diffusion coefficient decreases by ~5 order of magnitude from the perfect crystal structure. This suggests oxygen vacancies cause an increased capacity but at the expense of decreased rate capability of these materials. The chemical strain associated with both non-dilute lithium vacancies and dilute vacancies were analyzed with an anisotropic model. It was found that the oxygen vacancies and lithium vacancies are highly correlated causing the associated chemical expansion to not be a linear sum of the individual vacancy types. The predicted chemical strain due to a low energy VLi-VO-VLi¬ dumbbell structure can be correlated with the in situ experimentally measured stress. To investigate if the amount of oxygen vacancies can be controlled, the effects of Si and Al dopants were also studied. The silicon was shown to decrease the oxygen vacancy formation energy in neighboring octahedral to the silicon, thus suggested to activate the manganese and increase the capacity of the materials, consistent with experimental observations. Lastly, the impact of surface oxygen vacancies on adsorption and decomposition of an electrolyte component, ethylene carbonate (EC), on the Li¬2MnO3 surface was investigated. A two proton removal reaction from EC to Li2MnO3 (131) was discovered, suggesting some beneficial effect on the perfect Li2MnO3 surface. However, an EC appears to be repelled near a surface oxygen vacancy. The released oxygen can react with the EC molecule and trigger different decomposition reactions. Overall, the oxygen vacancies generated in the lithium-rich layered cathode materials are shown to have a very highly correlated impact on lithium, dopant and electrolyte-surface interactions which therefore can significantly impact battery performance and life.
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Title: Computational methods for understanding environmental processes and toxicity
Creator: Gao, Feng (Graduate of Michigan State University)
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Understanding environmental processes, risks and toxicities of persistent organic pollutants (POPs) are needed to protect human and ecosystem health. Usually the toxic effects of POPs on human health are assessed using a variety of time- and cost-intensive in vivo and in vitro experiments; in vivo evaluations utilizing animals and further complicated by ethical concerns. Computational models provide an alternative way to laboratory based experiments. Indeed, computational models have recently...
Show moreUnderstanding environmental processes, risks and toxicities of persistent organic pollutants (POPs) are needed to protect human and ecosystem health. Usually the toxic effects of POPs on human health are assessed using a variety of time- and cost-intensive in vivo and in vitro experiments; in vivo evaluations utilizing animals and further complicated by ethical concerns. Computational models provide an alternative way to laboratory based experiments. Indeed, computational models have recently become widely used to study reaction mechanisms, make predictions of chemical toxicity, and for risk assessment. In this dissertation, I study two computational methods that could potentially be used to advance remediation of dioxin and assess chemical toxicity: 1) molecular dynamics simulation of dioxin adsorption in activated carbon pores and 2) toxicity prediction with deep learning models, with a special focus on geometric scattering methods. Polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) are ubiquitous environmental contaminants that resist chemical, biological and physical routes of dissipation. They are well known for their toxicity, including adverse effects on reproductive health, impairment of mammalian immunity, and carcinogenicity. Adding activated carbons (ACs) to soils or sediments has been suggested as a means to promote the sequestration of polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs) in forms with reduced bioavailability and hence toxicity to humans and other mammals. However, the mechanisms and adsorption processes of dioxin by ACs are not well understood. Thus, molecular dynamics simulations were used to study the mechanism of dioxin adsorption in AC pores, and to evaluate the effects of pore size on dioxin adsorption. The results showed that smaller pores created a comparatively more hydrophobic sub-aqueous environment that promoted the adsorption of dioxins. Deep learning has achieved great successes in image recognition, natural language processing and many other tasks. Recently, the application of deep learning methods for toxicity predictions of organic molecules has gained increasing interest. Molecules can be treated as graphs, where atoms are nodes and bonds are edges. However regular deep learning methods cannot be directly applied to data in a non-Euclidean space such as graphs. Therefore, geometric scattering methods that generalize regular scattering transforms to non-Euclidean spaces are proposed herein. Scattering transforms was used to provide mathematical understanding of convolutional networks. The results in this dissertation showed that geometric scattering methods achieved near state-of-art results on multiple standard graph classification tasks, and can be used for various explorations of biochemical data. Finally, geometric scattering was applied for toxicity prediction with real-world toxicity datasets. The results demonstrate that it has excellent potential as an alternative approach for toxicity predictions.
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Title: Identification and functional characterization of the aryl hydrocarbon receptor protein interaction network
Creator: Tappenden, Dorothy May
Date: 2010
Collection: Electronic Theses & Dissertations
Description: Poly aromatic hydrocarbon (PAH) compounds are pervasive environmental contaminates. PAHs are by-products of industrial processes such as, paper bleaching, pesticide production, fossil fuel combustion, and waste incineration. These compounds are highly stable and lipophilic, leading to their bio-accumulation in soil and the food chain. Exposure to PAHs elicits toxic responses in mammals. Some of these responses include chloracne, liver hyperplasia, and immune system suppression. Moreover,...
Show morePoly aromatic hydrocarbon (PAH) compounds are pervasive environmental contaminates. PAHs are by-products of industrial processes such as, paper bleaching, pesticide production, fossil fuel combustion, and waste incineration. These compounds are highly stable and lipophilic, leading to their bio-accumulation in soil and the food chain. Exposure to PAHs elicits toxic responses in mammals. Some of these responses include chloracne, liver hyperplasia, and immune system suppression. Moreover, increased risk of diabetes, cancer, infertility, and birth defects correlate with PAH exposure. There are several families of compounds classified as PAHs. Two of the more infamous PAH groups are polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins (PCDDs). 2,3,7,8 tetrachlorodibenzo-p-dioxin (TCDD) is the hallmark dioxin congener and one of the most toxic PAHs known. Toxic responses to PAHs are mediated through the aryl hydrocarbon receptor (AHR). The AHR is a ligand activated member of the PER-ARNT-SIM (PAS) superfamily of transcription factors. PAS protein family members act as environmental sensors. PAHs bind the AHR, instigating its translocation to the nucleus, heterodimerization, and activation of its ability to regulate the transcription of genes. Though AHR gene regulation is well characterized, a complete understanding of the receptor mediated mechanisms underlying dioxin toxicity is lacking. This project focused on AHR protein interactions and potential roles these interactions have in toxic responses to TCDD exposures. The first aim was to establish the AHR protein interaction network (AHR-PIN). Using tandem affinity purification (TAP) and mass spectrometry we have established AHR-PINs in the presence and absence of TCDD. Changes in the PIN were observed between the dosed and vehicle treated samples. In addition, flux in the network dependent on length of exposure was observed. There were a number of protein hits identified in the PINs that are of interest. These proteins include Smarcad (a DNA helicase), Cfcl and Alcam (immune response proteins), and Arf-GAP. Finally, an interaction between the AHR and ATP5α1, a subunit of the ATP synthase complex which controls cellular energy homeostasis, is of particular interest. This interaction is the first to link the AHR to mitochondrial energy production. The second aim of this project was to establish functional relevance associated with the identified protein interactions. To that end, further investigation revealed a TCDD induced AHR dependent hyperpolarization of the mitochondrial inner membrane. This novel function may provide insight into the underlying mechanisms of TCDD induced toxicity. Mitochondrial dysregulation could play a key role in wasting syndrome and metabolic diseases. The findings establish the dynamic nature of the AHR-PIN and identify a potentially novel function of the AHR in cellular energy homeostasis.
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Title: A study of the water supply of St. Joseph, Michigan
Creator: Wells, James D.
Date: 1933
Collection: Electronic Theses & Dissertations

Title: Probing proton cross-shell excitations in 20772070Ni using nucleon knockout reactions
Creator: Elman, Brandon Alexander
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The neutron-rich Ni isotopes serve as an important benchmark for nuclear structure modelsbecause they exhibit interesting phenomena such as shape or configuration coexistencedriven by cross-shell excitations. Reported here are the excited-state population distributionsfollowing one-proton, one-neutron, and two-proton knockout from 71Cu, 71Ni, and72Zn, respectively, into excited states of 70Ni. By comparing these final-state populations,this work will attempt to determine the role of neutron...
Show moreThe neutron-rich Ni isotopes serve as an important benchmark for nuclear structure modelsbecause they exhibit interesting phenomena such as shape or configuration coexistencedriven by cross-shell excitations. Reported here are the excited-state population distributionsfollowing one-proton, one-neutron, and two-proton knockout from 71Cu, 71Ni, and72Zn, respectively, into excited states of 70Ni. By comparing these final-state populations,this work will attempt to determine the role of neutron and proton excitations separatelyin the configurations of excited states. The specific aim is to identify those excited statesassociated with configurations containing proton excitations across the Z = 28 shell gap.These levels are suggested in the literature to be associated with prolate deformation atrelatively low excitation energy compared to neighboring isotopes in the nickel chain.
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Title: Meta-analyses of gene expression in age-dependent diseases
Creator: Rogers, Lavida Rashida Kenera
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Physiological changes with age such as immune system decline and brain aging cause an increased risk for diseases. Age-related diseases are of major concern especially in the elderly population due to there being an increase in the average lifespan. This dissertation explores neurodegenerative and respiratory diseases and how gene expression varies due to disease status, age tissue and sex.Alzheimer's disease (AD) has been categorized by the Centers for Disease Control and Prevention (CDC) as...
Show morePhysiological changes with age such as immune system decline and brain aging cause an increased risk for diseases. Age-related diseases are of major concern especially in the elderly population due to there being an increase in the average lifespan. This dissertation explores neurodegenerative and respiratory diseases and how gene expression varies due to disease status, age tissue and sex.Alzheimer's disease (AD) has been categorized by the Centers for Disease Control and Prevention (CDC) as the 6th leading cause of death in the United States. AD is a significant health-care burden because of its increased occurrence (specifically in the elderly population), and the lack of effective treatments and preventive methods. AD targets neuronal function and can cause neuronal loss due to the buildup of amyloid-beta plaques and intracellular neurofibrillary tangles.The respiratory disease, chronic obstructive pulmonary disease (COPD), was classified by the Centers for Disease Control and Prevention in 2014 as the 3rd leading cause of death in the United States. The main cause of COPD is exposure to tobacco smoke and air pollutants. In addition to exploring genetic variation due to disease state, sex and age we also explored the role of smoking status on expression profiles.Additionally, the respiratory infections, influenza and pneumonia affect thousands of people worldwide. Young children, elderly and immunocompromised individuals are at higher risk for being infected by the influenza virus and Streptococcus pneumoniae. Host responses to these pathogens and vaccinations vary by the state of one's immune system.This dissertation includes multiple meta-analyses to assess genetic variation in Alzheimer's disease, COPD and Influenza, and an assessment of pneumococcal disease and aging. To identify significant differentially expressed genes we ran an analysis of variance with a linear model with disease state, age, sex, tissue, smoking status and study as effects that also included binaryinteractions.Our meta-analysis approach effectively combined multiple publicly available microarray datasetsto identify gene expression differences across diseases including full age, sex, smoking status and tissue type considerations. Our findings provide potential gene and pathway associations that can be targeted to improve treatment and prevention of diseases.
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Title: Electrochemistry of nanostructured carbon materials in aqueous electrolytes and room temperature ionic liquids
Creator: Jarosova, Romana
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Carbon is one of the most plentiful elements on the planet. From a materials perspective, carbon is unique because of the microstructurally distinct allotropes it forms. These include single and polycrystalline diamond, diamond-like carbon, glassy carbon, and graphite. All of these carbon materials are commonly used in electroanalysis, energy storage and conversion, separation, and chemical analysis, due to numbers of reasons, including low cost, high mechanical strength, wide usable...
Show moreCarbon is one of the most plentiful elements on the planet. From a materials perspective, carbon is unique because of the microstructurally distinct allotropes it forms. These include single and polycrystalline diamond, diamond-like carbon, glassy carbon, and graphite. All of these carbon materials are commonly used in electroanalysis, energy storage and conversion, separation, and chemical analysis, due to numbers of reasons, including low cost, high mechanical strength, wide usable potential range, rich surface chemistry, chemical inertness, and compatibility with a variety of solvents and electrolytes. For the optimal usage of carbon electrodes in electrochemistry, it is critical to fully understand and control the variables that impact background voltammetric current, capacitance, and heterogeneous electron-transfer kinetics at these materials. Over the years of carbon electrode usage in electrochemistry, much knowledge has been gained about the structure-function relationship at sp2- and sp3- bonded carbon electrodes. Nevertheless, as most of this knowledge pertains to aqueous electrolyte solution, there is still a significant gap about the properties of the electric double layer and the transport processes near the electrode interface in room temperature ionic liquids. The room temperature ionic liquids are solvent-free medium, composed purely of ions, with a melting point near or below room temperature. In electrochemistry, they are appreciated for several of their excellent properties, such as wide working potential window, moderate electrical conductivity, high thermal and chemical stability, negligible vapor pressure etc. As the RTILs does not contain any solvent, their interfacial structure at an electrified interface is significantly distinguished from the conventional Gouy-Chapman-Stern model describing the double layer in aqueous solutions. Additionally, also the redox analyte environment in RTILs is expected to different compared to those in aqueous solutions. The work in this dissertation thesis is focused on the electrochemical performance of microstructurally different carbon electrodes in aqueous electrolytes and room temperature ionic liquids. The physical, chemical and electronic properties of glassy carbon, boron-doped diamond, and tetrahedral amorphous carbon electrodes are discussed. Furthermore, the microstructure of carbon electrodes is correlated to the heterogeneous electron transfer rate constants of soluble inorganic and organic redox couples in aqueous electrolytes and room temperature ionic liquids. The attention was primarily focused on tetrahedral amorphous carbon electrode that can be doped with nitrogen, resulting in significant physical, chemical an electrochemical properties. Moreover, the electrode surface chemistry was alternated by an oxygen plasma modification and its effect on the electrochemical performance (background voltammetric current, capacitance and electron transfer kinetics), as well as potential surface damage was studied. Lastly, as it is believed that the nitrogen incorporated tetrahedral amorphous material possesses an equally superb properties compared to the boron doped diamond, both electrode materials were used for determination of endocrine disruption compounds, specifically estriol, estradiol and estrone, using high-pressure liquid chromatography with electrochemical detection. The detection figures of merit for both boron doped diamond and nitrogen-incorporated tetrahedral amorphous carbon thin-film electrodes were determined.
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Title: Three essays on labor and health economics
Creator: Jun, Dajung
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Nonportable fringe benefits, such as health insurance and retirement benefits, can influence an individual's career decisions and financial well-being. To protect employee's utility, state and federal governments enacted policies that regulated these benefits. The first two chapters of my dissertation study two such policies: tax credits for private health insurance coverage and dependent coverage mandates that allowed young adults to be covered through their parents' insurance. I examine the...
Show moreNonportable fringe benefits, such as health insurance and retirement benefits, can influence an individual's career decisions and financial well-being. To protect employee's utility, state and federal governments enacted policies that regulated these benefits. The first two chapters of my dissertation study two such policies: tax credits for private health insurance coverage and dependent coverage mandates that allowed young adults to be covered through their parents' insurance. I examine the effects of these policies on several health and labor market outcomes. In the last chapter, my coauthor and I explore a slightly different perspective on fringe benefits. We examine to what extent lifetime earnings could explain the variation in wealth at retirement. By researching these topics, I contribute to the understanding of how fringe benefits and lifetime earnings affected outcomes of rational decision-making: health insurance take-up, job mobility and wealth accumulation.In chapter 1, I investigate the effectiveness of tax credits on health insurance premiums. There was a renewed interest in using tax credits to increase health insurance coverage after the push to repeal the Affordable Care Act (ACA). The Health Insurance Tax Credit (HITC) was implemented between 1991--1993 to reduce the burden of health insurance premiums primarily for low-income families. Although it was active for three years, this policy has been studied in only one previous study. In this chapter, I examine the effectiveness of the HITC by using the Survey of Income Program Participation (SIPP), and I provide the first estimates of its effects on healthcare utilization and self-reported health status. My results align with previous studies and suggest the HITC increased the health insurance take-up by 5.8 percentage points. The implementation of the HITC also significantly improved the self-reported health status of respondents.In the second chapter, I analyze the effects of dependent coverage mandates on working fathers' job mobility and compensation. Due to the low rates of health insurance coverage among young adults, some state governments began mandating health insurance companies to allow adult children to stay on their parents' health insurance plans. First implemented in 1995, these mandates aimed to increase health coverage among young adults. In 2010, the federal government enacted a more comprehensive version of the dependent coverage mandate as part of the Affordable Care Act. These state- and federal-level efforts successfully increased insurance rates for young adults, but they might have also come with unintended consequences for parents. Parents who placed a high value on health insurance for their young adult children might be reluctant to leave jobs with employer-provided health insurance, and employers might offset the mandated-incurred health care costs by reducing other types of employee benefits or earnings. To assess the extent of such consequences, I study the effects of both the state and federal dependent health insurance mandates on fathers. By analyzing the 2004 and 2008 SIPP panels, which are linked with Detailed Earnings Records and Business Registrar data from the United States Census, I examine the mandates' effects on fathers' voluntary job separation rates (job-lock and job-push) and changes in their compensation. After the implementation of the mandates, I observe a significant decrease in the likelihood of voluntary job separation among eligible working fathers aged 45--64 with employer-provided health insurance. Additionally for these fathers, except for those who separated from these jobs within the current wave, my analysis slightly evidences that the mandates reduced the total monetary compensation. In the last chapter, we investigate the impact of lifetime earnings on retirement wealth. Historically, many households accumulated substantial wealth by retirement, while many other households accumulated very little. Venti and Wise (1999, 2001) directly examine this question by utilizing data that was superior to that available to previous researchers and conclude that th03000300e bulk of the dispersion must be attributed to differences in the amount that households choose to save.'' In this paper, we examine the extent that a remaining problem in their data affected their results: Their measure of lifetime earnings, despite being based on administrative data, was subject to topcoding in each year. Using the 2001 SIPP that was not subject to the same problem, we find that the effect of the topcoding was substantial. At least 35 percent of individuals were misclassified in each of the top four deciles. When replicating a key result of Venti and Wise (2001), our findings suggest that the correlation between lifetime earnings and savings was about 50\\% greater than what was found when using censored deciles. This increased explanatory power came largely at the expense of the other variables in the regression model.
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Title: Computational developments for ab initio many-body theory
Creator: Lietz, Justin Gage
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Quantum many-body physics is the body of knowledge which studies systems of many interacting particles and the mathematical framework for calculating properties of these systems. Methods in many-body physics which use a first principles approach to solving the many-body Schrodinger equation are referred to as ab initio methods, and provide approximate solutions which are systematically improvable. Coupled cluster theory is an ab initio quantum many-body method which has been shown to provide...
Show moreQuantum many-body physics is the body of knowledge which studies systems of many interacting particles and the mathematical framework for calculating properties of these systems. Methods in many-body physics which use a first principles approach to solving the many-body Schrodinger equation are referred to as ab initio methods, and provide approximate solutions which are systematically improvable. Coupled cluster theory is an ab initio quantum many-body method which has been shown to provide accurate calculations of ground state energies for a wide range of systems in quantum chemistry and nuclear physics. Calculations of physical properties using ab initio many-body methods can be computationally expensive, requiring the development of efficient data structures, algorithms and techniques in high-performance computing to achieve numerical accuracy.Many physical systems of interest are difficult or impossible to measure experimentally, and so are reliant on predictive and accurate calculations from many-body theory. Neutron stars in particular are difficult to collect observational data for, but simulations of infinite nuclear matter can provide key insights to the internal structure of these astronomical objects. The main focus of this thesis is the development of a large and versatile coupled cluster program which implements a sparse tensor storage scheme and efficient tensor contraction algorithms. A distributed memory data structure for these large, sparse tensors is used so that the code can run in a high-performance computing setting, and can thus handle the computational challenges of infinite nuclear matter calculations using large basis sets. By validating these data structures and algorithms in the context of coupled cluster theory and infinite nuclear matter, they can be applied to a wide range of many-body methods and physical systems.
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Title: Large-eddy simulations of turbulent flows in internal combustion engines
Creator: Banaeizadeh, Araz
Date: 2010
Collection: Electronic Theses & Dissertations
Description: The two-phase compressible scalar filtered mass density function (FMDF) model is further developed and employed for large-eddy simulations (LES) of turbulent spray combustion in internal combustion (IC) engines. In this model, the filtered compressible Navier-Stokes equations are solved in a generalized curvilinear coordinate system with high-order, multi-block, compact differencing schemes for the turbulent velocity and pressure. However, turbulent mixing and combustion are computed with a...
Show moreThe two-phase compressible scalar filtered mass density function (FMDF) model is further developed and employed for large-eddy simulations (LES) of turbulent spray combustion in internal combustion (IC) engines. In this model, the filtered compressible Navier-Stokes equations are solved in a generalized curvilinear coordinate system with high-order, multi-block, compact differencing schemes for the turbulent velocity and pressure. However, turbulent mixing and combustion are computed with a new two-phase compressible scalar FMDF model. The spray and droplet dispersion/evaporation are modeled with a Lagrangian method. A new Lagrangian-Eulerian-Lagrangian computational method is employed for solving the flow, spray and scalar equation. The pressure effect in the energy equation, as needed in compressible flows, is included in the FMDF formulation.The performance of the new compressible LES/FMDF model is assessed by simulating the flow field and scalar mixing in a rapid compression machine (RCM), in a shock tube and in a supersonic co-axial jet. Consistency of temperatures predicted by the Eulerian finite-difference (FD) and Lagrangian Monte Carlo (MC) parts of the LES/FMDF model are established by including the pressure on the FMDF. It is shown that the LES/FMDF model is able to correctly capture the scalar mixing in both compressible subsonic and supersonic flows.Using the new two-phase LES/FMDF model, fluid dynamics, heat transfer, spray and combustion in the RCM with flat and crevice piston are studied. It is shown that the temperature distribution in the RCM with crevice piston is more uniform than the RCM with flat piston. The fuel spray characteristics and the spray parameters affecting the fuel mixing inside the RCM in reacting and non-reacting flows are also studied. The predicted liquid penetration and flame lift-off lengths for respectively non-reacting and reacting sprays are found to compare well with the available experimental data. Temperatures and evaporated fuel mass fractions as predicted by the LES-FD and FMDF-MC for both reacting and non-reacting cases are shown to be consistent inside the RCM.Several non-reacting and reacting flows relevant to IC engines are also simulated with the new two-phase LES/FMDF model. The non-reacting flows in three geometrical configurations are considered: (1) a poppet valve in a sudden expansion, (2) a simple piston-cylinder assembly with a stationary open valve and harmonically moving flat piston, and (3) a realistic 3-valve single-cylinder direct-injection spark-ignition engine. The first and the second configurations are considered for validation of LES and for better understanding of the large-scale unsteady flow motions around the valve in the cylinder as generated by the piston movement. The predicted flow statistics by LES for the first two configurations compare well with the available experimental data. The LES results for third flow configuration show significant cycle-to-cycle variations (CCV) in the velocity field but insignificant CCV in the thermodynamic variables. During the intake stroke, the in-cylinder flow is highly inhomogeneous and turbulent, but during the compression stroke the flow becomes more homogeneous as turbulent decays. Turbulent mixing and combustion (with and without spray) in the 3-valve engine are simulated using the new two-phase compressible LES/FMDF model. Consistency of LES and FMDF results for single-phase reacting flows without spray but with flame ignition and premixed flame propagation, and two-phase reacting flows with spray, mixing and non-premixed combustion indicates the applicability and accuracy of the LES/FMDF model for complex turbulent combustion systems with moving boundaries.
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Title: Essays on the economics of organ transplantation
Creator: Lemont, Bethany I.
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Chapter 1: The Effect of Share 35 for Kidneys on Pediatric Transplant Candidates: Due to the shortage of donated kidneys in the United States, allocation policy is used to balance equity and efficiency in distribution of these scarce resources. I analyze the effect of a change in the allocation system for deceased donor kidneys called "Share 35" that gave priority to pediatric kidney transplant candidates over adult candidates for young deceased donor kidneys. Using data from the Scientific...
Show moreChapter 1: The Effect of Share 35 for Kidneys on Pediatric Transplant Candidates: Due to the shortage of donated kidneys in the United States, allocation policy is used to balance equity and efficiency in distribution of these scarce resources. I analyze the effect of a change in the allocation system for deceased donor kidneys called "Share 35" that gave priority to pediatric kidney transplant candidates over adult candidates for young deceased donor kidneys. Using data from the Scientific Registry of Transplant Recipients on all kidney transplant candidates in the US, I show that providing priority for pediatric candidates increased the average kidney quality by 30% and increased the likelihood of being transplanted within a year by 20 percentage points for pediatric candidates who are predicted to receive a deceased donor kidney in absence of Share 35. However, this policy also created an incentive for pediatric candidates with a living donor available to them to forgo using that donor to use a deceased donor instead. These candidates, who I estimate switch donor types, experience worse average kidney quality but no change in wait time. Additionally using the limited long run follow-up data available, the policy does not appear to have the unintended consequence of candidates with available living donors strategically "saving" their living donor for their second transplants when they would no longer have pediatric priority.Chapter 2: The Effects of the Affordable Care Act on the Demand for Organ Transplants: Many potential transplant candidates are unable to be registered on the wait list to receive an organ for transplant due to their lack of insurance. With the introduction of the Affordable Care Act, some of these potential candidates obtained insurance coverage through state Medicaid expansions or through the introduction of the private insurance marketplace. In this paper, I estimate the effect of this increase in availability of insurance coverage on these potential transplant candidates' wait list decisions and transplant outcomes using a difference in differences model. I find that the state expansions of Medicaid increased monthly wait list registrations by candidates insured through Medicaid by about 50 percent on average for all organs, but I find no effect of the marketplace on registrations. Additionally, I find that for candidates insured through Medicaid, the Medicaid expansion led to an increase in monthly deceased donor transplants for all organs, and a doubling of monthly living donor liver transplants.Chapter 3: Opioids and Organs: How Overdoses Affect the Supply of Donors,Waiting Lists, and Transplant Outcomes (with Stacy Dickert-Conlin, Todd Elder, and Keith Teltser): As the number of fatal drug overdoses has rapidly grown in recent years, patients awaiting organ transplants may be the unintended beneficiaries. In 2017, 70,237 people died due to a drug overdose, 5,795 transplant candidates died while waiting for an organ, and an additional 6,363 candidates were removed from waiting lists because they were too sick to accept a transplant. In this paper, we use mortality data from the National Vital Statistics System, merged with restricted-use data on transplant candidates and recipients from the Scientific Registry of Transplant Recipients, to study the extent to which the recent growth in fatal drug overdoses impacts the supply of deceased organ donations and transplants. We find that each opioid overdose death generates 0.019 additional organ donors, resulting in 0.053 additional organ transplants. Nearly all of this association is concentrated among donors aged 18-49, who account for the majority of opioid overdose victims. Somewhat surprisingly, opioid-driven supply shocks induce limited demand-side responses.
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Title: Mechanisms of tetrodotoxin production and resistance in the poisonous rough-skinned newt (Taricha granulosa
Creator: Vaelli, Patric M.
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Rough-skinned newts (Taricha granulosa) are poisonous salamanders that possess high concentrations of tetrodotoxin (TTX), a potent neurotoxin that blocks voltage-gated sodium channel (Nav) conductance in neurons and muscle cells. TTX is present in all species of the genus Taricha, but some populations of T. granulosa (hereafter “newts”) possess extreme quantities not seen in any other TTX-bearing species, including puffer fishes, blue-ringed octopuses, and many diverse marine invertebrates....
Show moreRough-skinned newts (Taricha granulosa) are poisonous salamanders that possess high concentrations of tetrodotoxin (TTX), a potent neurotoxin that blocks voltage-gated sodium channel (Nav) conductance in neurons and muscle cells. TTX is present in all species of the genus Taricha, but some populations of T. granulosa (hereafter “newts”) possess extreme quantities not seen in any other TTX-bearing species, including puffer fishes, blue-ringed octopuses, and many diverse marine invertebrates. Geographic variation in TTX toxicity across different newt populations is thought to be driven by ecological interactions with predators. Despite the central role of TTX in the physiology and evolution of newts, the mechanisms of TTX production and neurophysiological resistance are unknown. Because of the polyphyletic distribution of TTX toxicity among animals, we explored the hypothesis that TTX is produced by symbiotic skin bacteria in newts. We conducted 16S rRNA gene-based sequencing surveys to characterize skin- associated bacterial communities of newts from toxic and non-toxic populations. From here, we employed ecologically-guided cultivation strategies to target skin-associated symbionts and produce pure cultures. We screened cultures for TTX production using a customized HILIC-MS/MS method and confirmed TTX production in multiple isolated bacterial strains. Furthermore, we investigated the molecular adaptations underlying apparent TTX resistance in the Navs of newts. We cloned and sequenced the TTX binding site, the S5-S6 pore loop regions, of all six Nav genes present in this species and compared sequences from toxic and non-toxic populations, as well as from other vertebrates. As a result, we identified several mutations present in the S5-S6 pore loops of all six genes, indicating a remarkable parallel evolution of TTX resistance across the Nav gene family. To determine whether these mutations impact TTX resistance, we used site-directed mutagenesis to insert three newt mutations identified in neural subtype Nav1.6 into the TTX-sensitive mouse ortholog and examined their effects on TTX binding by heterologous expression and electrophysiological recording in Xenopus laevis oocytes. We found that each individual mutation increased TTX resistance to varying degrees, but the triple mutant was extremely resistant to TTX concentrations exceeding 100 μM. Taken together, our results indicate that TTX is derived from the skin microbiome in the extremely toxic rough-skinned newt and that multiple adaptations in newt Navs were required for the nervous system to adapt to TTX toxicity. Overall, this research contributes to a growing understanding that symbiotic microbes can affect the physiology of animal hosts and their nervous systems, and that evolution by natural selection may target genetic variation across both host and symbiont genomes, collectively termed the ‘hologenome’.
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Title: Mobile phone habits during face to face first encounters : an investigation of self-disclosure and nonverbal mimicry
Creator: Kadylak, Travis
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Mobile phones are widely adopted around the world. In contemporary society, mobile phone use is acutely integrated into core social and psychological aspects of everyday life, such as verbal and nonverbal interpersonal communication. Though mobile phones offer users many affordances for social connection that can facilitate interpersonal communication and affiliation formation, previous research on phubbing [phone-snubbing] suggests that mobile phone use during face to face (FtF) interactions...
Show moreMobile phones are widely adopted around the world. In contemporary society, mobile phone use is acutely integrated into core social and psychological aspects of everyday life, such as verbal and nonverbal interpersonal communication. Though mobile phones offer users many affordances for social connection that can facilitate interpersonal communication and affiliation formation, previous research on phubbing [phone-snubbing] suggests that mobile phone use during face to face (FtF) interactions can breach interpersonal expectations, be perceived as ostracizing, hinder judgements of intimacy and communication quality, lead to unfavorable interpersonal evaluations, cause conflict within relationships, and impede affiliation formation. I aimed to advance expectancy violation theory (EVT) by using the axioms of the theory to make predictions involving nonverbal behaviors (e.g., phubbing expectancy violations and mobile phone mimicry), interpersonal judgements, and self-disclosure. Much like self-disclosure, humans evolved to automatically engage in nonverbal mimicry, or synchronous behavioral matching (i.e., automatically or unintentionally touching one's face after their interaction partner engaged in the same behavior), as a means of building affiliation and promoting positive interpersonal judgements. Following this premise, I examined whether mobile phone checking mimicry, or behavioral matching between FtF interaction partners involving how they use their mobile phones, may promote positive interpersonal judgements (e.g., increased perceived liking, trust, and empathy) that subsequently may be associated with higher levels of self-disclosure. Phubbing effects research currently maintains that mobile phone use, during FtF interactions, tends to lead to adverse interpersonal outcomes among mobile phone users of all ages. However, I used a 2x1 between subject laboratory experiment with college students (N = 77) to assess whether phubbing, expectancy violations, and mobile phone checking mimicry influenced interpersonal judgements and self-disclosure within the context of a face-to-face get-to-know-you activity. The results suggest that mobile phone checking, perceptions of negative phubbing expectancy violations, and mobile phone checking mimicry, may have limited effects on self-disclosure and interpersonal judgements in a get-to-know-you activity. Specifically, phubbing was inversely associated with self-disclosure; however, mobile phone checking mimicry was positively associated with self-disclosure. Though the external validity of the findings may be limited due to the student sample, this study advances expectancy violation theory by demonstrating the potential prosocial and antisocial effects of mobile phone use during FtF interactions. Additional study limitations, theoretical and practical implications, and directions for future research are discussed.
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Title: Motivating salespeople toward greater productivity
Creator: Good, Valerie Denise
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Company profitability depends on an active and engaged sales force; thus, managers continue to seek best practices for motivating salespeople to perform productively. This issue remains critical as salespeople typically have significant discretion in their work and serve as the face of the company to customers. Thus, I seek to develop a greater understanding of motivational forces to contribute to both personal selling theory and sales force management. The first essay of my dissertation is a...
Show moreCompany profitability depends on an active and engaged sales force; thus, managers continue to seek best practices for motivating salespeople to perform productively. This issue remains critical as salespeople typically have significant discretion in their work and serve as the face of the company to customers. Thus, I seek to develop a greater understanding of motivational forces to contribute to both personal selling theory and sales force management. The first essay of my dissertation is a meta-analysis, which synthesizes studies published between 1985 and 2019 on salesperson motivation to answer the following key questions: how are intrinsic and extrinsic motivation related to salesperson performance? In my second essay, I examine antecedents and outcomes of intrinsic motivation. In addition to the antecedents found in Self-Determination Theory, I explore the notion of sense of purpose and develop a scale for the construct, showing how it is distinct from related constructs in the literature. Using longitudinal, objective effort and performance measures provided by a large sales firm, findings reveal that intrinsic motivation is more positively associated with working hard, working smart, and salesperson performance than extrinsic motivation. In addition, the analyses demonstrate how sales managers' leadership styles can leverage both intrinsic and extrinsic motivation for increased effort, adaptivity, and performance over time. Finally, in the third essay, I demonstrate how to motivate salesperson resilience. Findings indicate that intrinsically motivated salespeople are more resilient than extrinsically motivated salespeople, and resilience is associated with better performance through working harder and working smarter; however, certain managerial interventions are needed to activate the resilience within salespeople for increased effort.
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