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Title: Linguistic strategies of entrepreneurial firms and financial resource acquisition
Creator: Pan, Lingling
Date: 2018
Collection: Electronic Theses & Dissertations
Description: "Resource acquisition from external investors is critical for the survival of entrepreneurial firms. Prior research indicated that an entrepreneurial firm's strategic use of language in public communication can enhance the firm's opportunity to obtain external funding. In this dissertation, I extend this line of research by focusing on the linguistic characteristics of an entrepreneurial firm's communication. Specifically, I focus on whether and how language vividness, a critical lexical...
Show more"Resource acquisition from external investors is critical for the survival of entrepreneurial firms. Prior research indicated that an entrepreneurial firm's strategic use of language in public communication can enhance the firm's opportunity to obtain external funding. In this dissertation, I extend this line of research by focusing on the linguistic characteristics of an entrepreneurial firm's communication. Specifically, I focus on whether and how language vividness, a critical lexical characteristic of an entrepreneurial firm's public communication, influences the firm's financial resource acquisition performance. Using entrepreneurial firms' IPO events as the study context, I examine the association between the level of language vividness of a firm's IPO prospectuses and its IPO performance. I argue that, in general, an entrepreneurial firm will have greater IPO success if its prospectus shows high usage of concrete and imagery words--the two primary dimensions of vivid language. Furthermore, I argue that the effects of vivid language are contingent on three factors: 1) the similarity of the language strategy the firm employs relative to the industry it is operating in; 2) the hotness of the IPO market the firm belongs; and 3) the specific content domain (section) in the IPO prospectus. Examining a sample of 679 IPO firms, I find that language concreteness and language imagery are positively associated with firm's IPO outcome. In addition, the hotness of IPO market that a firm belongs moderates the relationship between the firm's level of language imagery and IPO outcome."--Page ii.
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Title: Where the rivers come together : reclaiming and re-imagining indigenous history, identity, and language in the city
Creator: Haviland, Adam
Date: 2017
Collection: Electronic Theses & Dissertations
Description: The movement and migration of Native Americans to urban areas is usually traced to the urbanization programs of the 1950s and 1960s. However, the recent scholarship of Coll Thrush (2007) and John Low (2016) highlight the long history of urban spaces as Indigenous spaces and the role Indigenous people and communities have played in their growth and development. Similarly, the discourse of language loss and revitalization, urban spaces, and Indigenous urban communities are seen as places or...
Show moreThe movement and migration of Native Americans to urban areas is usually traced to the urbanization programs of the 1950s and 1960s. However, the recent scholarship of Coll Thrush (2007) and John Low (2016) highlight the long history of urban spaces as Indigenous spaces and the role Indigenous people and communities have played in their growth and development. Similarly, the discourse of language loss and revitalization, urban spaces, and Indigenous urban communities are seen as places or endpoints of assimilation. Thus, language revitalization efforts and programs often focus on reservations as the primary domains where Indigenous languages and their speakers persist and thrive. Yet, despite settler colonial narratives of vanishing that erase Indigenous people and Indigenous languages from urban areas, cities have, and continue to be, important intersections of movement and migration and with deep historical roots where Indigenous languages persist and thrive as ideological markers of identity, belonging, and as spoken languages.This Research shows how Lansing, Michigan, Nkwejong (the place where the rivers come together) has a long history as an Indigenous intersection and space that challenges the local settler-colonial narratives of removal and erasure. Lansing has remained an Indigenous space through traditions of movement and migration that were driven by the auto industry and educational opportunities. Through these movements, Anishinabek from reservations in and around Manitoulin Island came here in the 1960s and 1970s who were fluent speakers ofAnishinaabemowin. Anishinabek from Canada and local Anishinabek, who had lost the language, created community and belonging through educational programs. These spaces have become focal points where community comes together and, for many individuals, are the primary spaces where language, culture, and identity are reclaimed and passed on. However, these are also spaces of tension where gender roles, language ideologies, and linguistic practices concerning language as an ideological marker of identity and its role as a communicative system are challenged and reimagined.Through interviews with community members and participant observation, I explore relationships to urban and reservation “homelands,” the importance of education as places where individuals develop relationships to their identities and culture, and the role that language, as both an ideological marker of identity and belonging and as a communicative system, play in their everyday lives and experiences. While most participants agreed that language was important to preserving identity and traditional knowledge, their relationships with their identities as urban and Indigenous, and their relationships to Indigenous language, highlight: (1) the need to reexamine language ideologies that link Language to “traditional culture and Knowledge” and the impacts these ideologies have on language revitalization. (2) The importance of urban areas as Indigenous homelands and places where Indigenous languages persist, and (3) the role of education as intersections and places of tension where multiple ideologies, identities, and ways of being Indigenous are expressed and reimagined.
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Title: Computational study of strongly coupled charged particle systems
Creator: Dharuman, Gautham
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Exciting experiments in ultracold neutral plasmas, laser-matter interaction, charged particle stopping, mixing under extreme conditions etc., at academic facilities or at even larger facilities such as the National Ignition Facility, Z machine or the Linac Coherent Light Source, have necessitated the need for models that can simulate these systems at large length- and time-scales. This thesis summarizes my research work, falling within the category of computational plasma physics, aimed at...
Show moreExciting experiments in ultracold neutral plasmas, laser-matter interaction, charged particle stopping, mixing under extreme conditions etc., at academic facilities or at even larger facilities such as the National Ignition Facility, Z machine or the Linac Coherent Light Source, have necessitated the need for models that can simulate these systems at large length- and time-scales. This thesis summarizes my research work, falling within the category of computational plasma physics, aimed at three aspects: effective quantum potentials based method for non-equilibrium quantum electron dynamics at scale, efficient force calculation method for molecular dynamics simulation with screened Coulomb interactions, and an avenue based on compressed gases for creation of laboratory-scale tunable strongly coupled plasmas as a platform for understanding large-scale experiments. Effective classical dynamics provide a potentially powerful avenue for modeling large-scale dynamical quantum systems. We have examined the accuracy of a Hamiltonian-based approach that employs effective momentum-dependent potentials (MDPs) within a molecular-dynamics framework through studies of atomic ground states, excited states, ionization energies and scattering properties of continuum states. Working exclusively with the Kirschbaum-Wilets (KW) formulation with empirical MDPs [C. L. Kirschbaum and L. Wilets, PRA 21, 834 (1980)], leads to very accurate ground-state energies for several elements (e.g., N, F, Ne, Al, S, Ar and Ca) relative to Hartree-Fock values. The KW MDP parameters obtained are found to be correlated, thereby revealing some degree of transferability in the empirically determined parameters. We have studied excited-state orbits of electron-ion pair to analyze the consequences of the MDP on the classical Coulomb catastrophe. From the ground-state energies, we find that the experimental first- and second-ionization energies are fairly well predicted. Finally, electron-ion scattering was examined by comparing the predicted momentum transfer cross section to a semi-classical phase-shift calculation; optimizing the MDP parameters for the scattering process yielded rather poor results, suggesting a limitation of the use of the KW MDPs for plasmas. Efficient force calculation methods are needed for molecular dynamics simulation with medium-range interactions. Such interactions occur in a wide range of systems, including charged-particle systems with varying screening lengths. We generalize the Ewald method to charged systems described by interactions involving an arbitrary dielectric response function. We provide an error estimate and optimize the generalization to find the break-even parameters that separate a neighbor list-only algorithm from the particle-particle particle-mesh (PPPM) algorithm. We examine the implications of different choices of the screening length for the computational cost of computing the dynamic structure factor. We then use our new method in molecular dynamics simulations to compute the dynamic structure factor for a model plasma system and examine the wave-dispersion properties of this system. Laboratory-scale non-ideal plasmas with controllable properties over a wide range of densities below solid density are needed for understanding large-scale plasma experiments. Based on a suite of molecular dynamics simulations, we propose a general paradigm for producing such controllable non-ideal plasmas. We simulated the formation of non-equilibrium plasmas from photoionized, cool gases that are spatially precorrelated through neutral-neutral interactions that are important at moderate to high pressures. We examined the plasma-formation process over orders-of-magnitude variations in the initial gas pressure to characterize variations in several physical properties, including Coulomb collisional rates, partial pressures, screening strengths, continuum lowering, interspecies Coulomb coupling, electron degeneracy and ionization states. We find that variations in the initial gas pressure lead to controllable variations in a wide range of plasma properties, including the equation of state, collisional processes, atomic processes and basic plasma properties (coupling, screening and degeneracy). This paradigm has significant advantages over solid-density experiments because the collisional, collective and recombination timescales are reduced by a factor of 3 to 10, potentially broadening the efficacy of diagnostics. The paradigm also has advantages over ultracold plasma experiments because the trapping and cooling phases are avoided.
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Title: Maize production intensification in Kenya
Creator: Olwande, John Otieno
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Soil infertility is one of the major problems contributing to low and stagnated agricultural productivity in sub-Saharan Africa. In Kenya, this problem is manifested in maize where yields have remained low and stagnated over time despite increased use of inorganic fertilizers and improved seed varieties. More effective alternatives and/or complimentary actions to address this problem thus remains germane. This dissertation contributes to that endeavor through two broad objectives: to generate...
Show moreSoil infertility is one of the major problems contributing to low and stagnated agricultural productivity in sub-Saharan Africa. In Kenya, this problem is manifested in maize where yields have remained low and stagnated over time despite increased use of inorganic fertilizers and improved seed varieties. More effective alternatives and/or complimentary actions to address this problem thus remains germane. This dissertation contributes to that endeavor through two broad objectives: to generate evidence that can support decisions to address the problem of low agricultural productivity in general and of maize in particular in Kenya; and to contribute to the body of knowledge about agricultural intensification in sub-Saharan Africa.The first essay uses household panel survey data from rural Kenya covering a period of 13 years (1997 – 2010) to examine trends and patterns in land and labor productivity of maize, measured as net returns to land and to family labor. Results show declining landholdings and farm sizes but maize occupied over one-half of cultivated land. Land productivity declined by 42% for households with at least 10 acres and by 33% in the most important maize producing regions. Labor productivity increased in areas with smaller landholdings and higher population density because of increase in land productivity, and declined or only marginally increased in areas with larger landholdings and lower population density because of a decline in land productivity. These results demonstrate that increasing maize production and returns to family labor in Kenya will rely on improving yields especially in the major maize growing areas where this has declined.The second essay uses data on maize production in five major maize growing counties in Kenya to compare maize farmers’ perceived soil fertility to measured soil fertility. It also investigates the influence of farmers’ perceptions of soil fertility on their adoption (use) of soil fertility management practices. Results show little agreement between farmers’ perceived and measured soil fertility, and farmers mostly judge the fertility status of soil by crop performance. Farmers apply management practices that may not match the fertility needs of soil on their plots, exemplified by the persistent application of an acidifying fertilizer (diammonium phosphate (DAP)) and low application of organic soil amendments even on plots with soils that are acidic and deficient in organic carbon. Farmers on average are more likely to apply inorganic fertilizer to plots they perceive to be infertile, and they treat manure or compost and inorganic fertilizers as serving substitute roles in soil fertility. These results suggest policy and extension information gaps regarding soil fertility management.The third essay uses the same dataset as in the second essay together with rainfall data to estimate technical efficiency of maize farmers and the effect of farmers’ soil fertility perception on technical efficiency. It also demonstrates the importance of including environmental production conditions and agronomic practices in agricultural productivity and efficiency analysis. Average technical efficiency level is 0.75 and 0.70, respectively, with and without environmental variables and agronomic practices in the model, indicating that scope for increasing maize yield through better management of inputs exits and that omission of environmental variables and agronomic practices underestimates technical efficiency. Farmers’ perception of soil fertility and the consistency of their perception with measured soil fertility both have significant effects on technical efficiency, underscoring the importance of information that can enhance farmers’ accurate understanding about soil fertility conditions on their farms to help them make better production decisions.
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Title: Feasibility and application of a CuxO-based memristor for sensing oxygen and other gases
Creator: Nyenke, Chinwe Pamela
Date: 2017
Collection: Electronic Theses & Dissertations
Description: This dissertation introduces the design, fabrication, and application of acopper-oxide-based memristor for the passive sensing of oxygen and other gases.The device design was as follows: Deposition of copper (Cu) bottom electrodes,(oxygen) vacancy-rich copper oxide (CuxO) switching layers, and tungsten (W) topelectrodes in a crossbar array structure. The CuxO layer was deposited via reactivesputtering of a Cu target with an argon-oxygen (Ar/O2) mixture. A portion of thislayer was extended...
Show moreThis dissertation introduces the design, fabrication, and application of acopper-oxide-based memristor for the passive sensing of oxygen and other gases.The device design was as follows: Deposition of copper (Cu) bottom electrodes,(oxygen) vacancy-rich copper oxide (CuxO) switching layers, and tungsten (W) topelectrodes in a crossbar array structure. The CuxO layer was deposited via reactivesputtering of a Cu target with an argon-oxygen (Ar/O2) mixture. A portion of thislayer was extended from each array cell to be exposed for sensing. Memristivedevices of different switching layer thicknesses were initially explored forirreversible sensing of oxygen in ambient air. Results of this first experimentdemonstrated an increase in resistance states upon prolonged exposure toambient air. For the second experiment, memristive devices were fabricated withsub-micron holes that were etched into the W top electrode to better reveal theswitching layer surface. The devices were also subjected to ambient oxygen at 180deg C to induce passive sensing in minutes. Resistance results were consistentwith the first experiment but also revealed a dependence on the surface area ofthe exposed oxide. Finally, memristive devices were investigated in a thirdexperiment for reversible sensing of an oxidizing gas and reducing gas at roomtemperature. This time, changes were not only observed in resistance but also inhysteresis (current versus voltage) depending on the type of gas introduced.Overall, this work demonstrates a step towards the use of the memristor as a gassensor, which we have named “memsensors”, by taking advantage of the device’sability to memorize (or record) historical information.
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Title: Preservice teachers' intention to teach media and information literacy in their future classroom : an application of the theory of planned behavior
Creator: Gretter, Sarah
Date: 2017
Collection: Electronic Theses & Dissertations
Description: "This dissertation is a multi-phase study looking at preservice teachers' intention to teach Media & Information Literacy in their future classroom. Each of the three studies presented in this dissertation answered a specific question: 1) What do preservice teachers think about teaching MIL? 2) What predicts preservice teachers' intention to teach MIL? and 3) How can we support preservice teachers' intention to teach MIL? The first paper in this dissertation reported on an elicitation study...
Show more"This dissertation is a multi-phase study looking at preservice teachers' intention to teach Media & Information Literacy in their future classroom. Each of the three studies presented in this dissertation answered a specific question: 1) What do preservice teachers think about teaching MIL? 2) What predicts preservice teachers' intention to teach MIL? and 3) How can we support preservice teachers' intention to teach MIL? The first paper in this dissertation reported on an elicitation study conducted with focus groups of preservice teachers to understand, from their perspectives, the factors that would either impede or facilitate the teaching of MIL in their future classroom. The second paper described the design, validation, and results of a survey based on these factors. The third paper reported on an online module with reflective exercises designed around the results gathered in the aforementioned survey. Each paper describes the findings that emerged from its study, followed by implications for research and practice, along with questions for the field of Media & Information Literacy education"--Page ii.
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Title: Role of a alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor on methylmercury-induced calcium dysregulation on motor neurons
Creator: Colón-Rodríguez, Alexandra
Date: 2017
Collection: Electronic Theses & Dissertations
Description: Methylmercury (MeHg) is a persistent environmental neurotoxicant to which humans are exposed mainly through the consumption of fish. MeHg leads to neuronal cell death in acute or chronic exposure and its mechanism of toxicity is not yet understood. Due to its high prevalence in the environment and its mechanism of toxicity MeHg has been considered a possible contributor to the development of Amyotrophic Lateral Sclerosis (ALS). Alterations in glutamate reuptake and Ca2+ regulation in ALS and...
Show moreMethylmercury (MeHg) is a persistent environmental neurotoxicant to which humans are exposed mainly through the consumption of fish. MeHg leads to neuronal cell death in acute or chronic exposure and its mechanism of toxicity is not yet understood. Due to its high prevalence in the environment and its mechanism of toxicity MeHg has been considered a possible contributor to the development of Amyotrophic Lateral Sclerosis (ALS). Alterations in glutamate reuptake and Ca2+ regulation in ALS and after MeHg exposures have been well documented. Most importantly, MeHg-induced alterations in intracellular Ca2+ ([Ca2+]i) in motor neurons lead to early onset ALS-like phenotype in the superoxide dismutase 1 (SOD1-G93A) mouse, a mouse model genetically susceptible to ALS. One of the ion channels that contribute to the alterations in [Ca2+]i observed in ALS and after MeHg exposure is the ionotropic glutamate receptor α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA). My research has focused on characterizing the effects of MeHg on motor neurons in vitro. I used two cell lines: a mouse motor neuron hybrid cell line NSC34 and an induced pluripotent stem cell derived-motor neuron (hiPSC-MN) cell line of human origin. I investigated MeHg toxicity in these cell types and on AMPA receptors in order to understand the role these ion channels play in the observed alterations in [Ca2+]i. Results from the studies in this dissertation demonstrate that MeHg exposure in vivo or in vitro lead to alterations in the AMPA receptor and the RNA editing enzyme ADAR2 gene expression. Also, that hiPSC-MNs are more susceptible than NSC34 cells to MeHg toxicity observed as an earlier concentration dependent cell death. I also identified that MeHg induces a bi-phasic increase in [Ca2+]i in hiPSC-MNs and Ca2+ permeable AMPA receptors are mediating those increases. Taken together these results suggest a potential role of the AMPA receptors in MeHg-induced toxicity in MNs. These findings contribute to the understanding of MeHg-induced toxicity in motor neurons and provide a platform for ongoing studies in our lab which are focused on identifying the underlying mechanisms by which MeHg is contributing to the accelerated onset of ALS-like phenotype.
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Title: Experimental and numerical investigation of confined premixed flame
Creator: Najim, Younis Mahal
Date: 2017
Collection: Electronic Theses & Dissertations
Description: Understanding the dynamics of premixed flames propagating during constant volume combustion is key to enhancing the performance of existing combustion devices, which provide 80% of the world’s energy supply, and reducing the impact of pollution on the environment. This work experimentally and numerically investigates confined premixed flame propagation in an initially quiescent mixture. Three combustion chambers are used; a curved wave disc engine channel and rectilinear channels of aspect...
Show moreUnderstanding the dynamics of premixed flames propagating during constant volume combustion is key to enhancing the performance of existing combustion devices, which provide 80% of the world’s energy supply, and reducing the impact of pollution on the environment. This work experimentally and numerically investigates confined premixed flame propagation in an initially quiescent mixture. Three combustion chambers are used; a curved wave disc engine channel and rectilinear channels of aspect ratio 7 and 10. The mixture is methane/air and syngas (H2/CO)/air initially at atmospheric pressure and room temperature. The channel walls are assumed to be isothermal to incorporate the effect of heat transfer. For two-dimensional analysis, the reaction rate is modeled using both detailed and reduced kinetic mechanisms. The mass diffusion is investigated using three different diffusion models with different levels of approximation; the multicomponent diffusion model of Chapman-Enskog including the Soret effect; the mixture-averaged model; and constant Lewis number. For three-dimensional analysis, a large eddy simulation coupled with the transport equation of the reaction progress variable is used. In this work, the reaction rate predicted using the Boger model of algebraic flame surface density is modified by incorporating a transient flame speed that accounts for the variation in the temperature and pressure of the unburned gases. The experimental measurements include schlieren photography to track the flame structure and propagation speed, and the pressure-time history during the combustion process is measured by a pressure sensor mounted in the channel wall. The experimental measurements validate the numerical simulation results and provide further understanding of the flame and pressure dynamics. Unlike behavior previously reported in straight or 90◦ bend channels, premixed flame propagation in the wave disc engine channel exhibits different features: the convex tulip flame converts back into a concave flame and thus reveals the influence of channel geometry on flame evolution. The experiments show that the rate of pressure change eventually becomes negative mainly due to heat losses that engender a correspondingly slower flame propagation during the final stage of burning. The analysis of the numerical results reveals the effect of the interaction between the flame front, pressure field, and flame-induced flow on flame evolution during all stages of flame structure development. The results also demonstrate that both multicomponent diffusion with the Soret effect and the mixture-averaged model produce slightly different results in flame speed, structure, peak temperature, and average pressure for the methane/air mixture, while the deviation is more pronounced for syngas flames. The methane/air flame produced by the unity Lewis number model, however, lags behind its counterparts during early stages and dramatically accelerates, at which time the values of peak temperature and average pressure show unrealistic behavior. Furthermore, unity Lewis number flames develop an artificial second tulip flame after the first tulip flame is annihilated. This second tulip flame is neither observed in the Chapman-Enskog and mixture-average simulations, nor in the experiments. This reveals the role of the Lewis number in the intrinsic thermodiffusive flame instabilities and tulip flame formation. The three-dimensional simulation uncovers an interesting behavior for the flame structure that is introduced here as a “transverse tulip” flame, which has not been previously reported. The “transverse tulip” flame evolves in the direction perpendicular to that of the initial tulip flame after the latter undergoes the transition from cusped convex back to the concave finger shape. The commonly used Zimont model produces an unrealistically diffused flame front. The large eddy simulation coupled with the here-modified algebraic flame surface density overcomes this issue and reproduces the experimental observations of the flame structure, pressure-time history, and burning time with good agreement.
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Title: Fluid animation on deforming surface meshes
Creator: Wang, Xiaojun (Graduate of Michigan State University)
Date: 2017
Collection: Electronic Theses & Dissertations
Description: "We explore methods for visually plausible fluid simulation on deforming surfaces with inhomogeneous diffusion properties. While there are methods for fluid simulation on surfaces, not much research effort focused on the influence of the motion of underlying surface, in particular when it is not a rigid surface, such as knitted or woven textiles in motion. The complexity involved makes the simulation challenging to account for the non-inertial local frames typically used to describe the...
Show more"We explore methods for visually plausible fluid simulation on deforming surfaces with inhomogeneous diffusion properties. While there are methods for fluid simulation on surfaces, not much research effort focused on the influence of the motion of underlying surface, in particular when it is not a rigid surface, such as knitted or woven textiles in motion. The complexity involved makes the simulation challenging to account for the non-inertial local frames typically used to describe the motion and the anisotropic effects in diffusion, absorption, adsorption. Thus, our primary goal is to enable fast and stable method for such scenarios. First, in preparation of the material properties for the surface domain, we describe textiles with salient feature direction by bulk material property tensors in order to reduce the complexity, by employing 2D homogenization technique, which effectively turns microscale inhomogeneous properties into homogeneous properties in macroscale descriptions. We then use standard texture mapping techniques to map these tensors to triangles in the curved surface mesh, taking into account the alignment of each local tangent space with correct feature directions of the macroscale tensor. We show that this homogenization tool is intuitive, flexible and easily adjusted. Second, for efficient description of the deforming surface, we offer a new geometry representation for the surface with solely angles instead of vertex coordinates, to reduce storage for the motion of underlying surface. Since our simulation tool relies heavily on long sequences of 3D curved triangular meshes, it is worthwhile exploring such efficient representations to make our tool practical by reducing the memory access during real-time simulations as well as reducing the file sizes. Inspired by angle-based representations for tetrahedral meshes, we use spectral method to restore curved surface using both angles of the triangles and dihedral angles between adjacent triangles in the mesh. Moreover, in many surface deformation sequences, it is often sufficient to update the dihedral angles while keeping the triangle interior angles fixed. Third, we propose a framework for simulating various effects of fluid flowing on deforming surfaces. We directly applied our simulator on curved surface meshes instead of in parameter domains, whereas many existing simulation methods require a parameterization on the surface. We further demonstrate that fictitious forces induced by the surface motion can be added to the surface-based simulation at a small additional cost. These fictitious forces can be decomposed into different components. Only the rectilinear and Coriolis components are relevant to our choice of local frames. Other effects, such as diffusion, adsorption, absorption, and evaporation are also incorporated for realistic stain simulation. Finally, we explore the extraction of Lagrangian Coherent Structure (LCS), which is often referred to as the skeleton of fluid motion. The LCS structures are often described by ridges of the finite time Lyapunov exponent (FTLE) fields, which describe the extremal stretching of fluid parcels following the flow. We proposed a novel improvement to the ridge marching algorithm, which extract such ridges robustly for the typically noisy FTLE estimates even in well-defined fluid flows. Our results are potentially applicable to visualizing and controlling fluid trajectory patterns. In contrast to current methods for LCS calculation, which are only applicable to flat 2D or 3D domains and sensitive to noise, our ridge extraction is readily applicable to curved surfaces even when they are deforming. The collection of these computational tools will facilitate generation of realistic and easy to adjust surface fluid animation with various physically plausible effects on surface."--Pages ii-iii.
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Title: Intrinsic motivation in a blended learning environment : an exploratory study
Creator: Zeller, Angelina N.
Date: 2018
Collection: Electronic Theses & Dissertations
Description: It is estimated that 75% of all K-12 schools in the United States incorporate some form of e-learning within their instructional program offerings (Watson, Pape, Murin, Gemin, & Vashaw, 2014). However, current research relating to the success of virtual learners is providing mixed results at best, with virtual course completion rates hovering around 58% (Freidhoff, 2017) and attrition rates as high as 80% in some e-learning courses (Bawa, 2016; Bonk, 2001; Moshinskie, 2001).The purpose of...
Show moreIt is estimated that 75% of all K-12 schools in the United States incorporate some form of e-learning within their instructional program offerings (Watson, Pape, Murin, Gemin, & Vashaw, 2014). However, current research relating to the success of virtual learners is providing mixed results at best, with virtual course completion rates hovering around 58% (Freidhoff, 2017) and attrition rates as high as 80% in some e-learning courses (Bawa, 2016; Bonk, 2001; Moshinskie, 2001).The purpose of this study was to understand the degree to which students who were new to a blended learning program were motivated toward tasks aimed at developing 1) a sense of community; 2) e-skills, 3) self-regulation, and 4) goal-setting; and to examine whether motivation in these domains is predictive of continued enrollment, progressing in school and academic engagement during their first semester in the program. This study provided an intimate window through which to view students’ sociodemographic characteristics, motivations and outcomes in this cyber school blended learning model, with key findings related to sociodemographic background and motivational characteristic variables statistically significant to important education outcomes.
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Title: Effects of dimensions of word knowledge and their accessibility on different levels of reading comprehension in adolescent EFL learners
Creator: Choi, Yunjeong
Date: 2017
Collection: Electronic Theses & Dissertations
Description: Researchers have investigated that different dimensions of word knowledge (breadth versus depth) may play distinct roles in second language (L2) reading comprehension. Yet, little research has addressed how learners’ efficiency of accessing those dimensions of knowledge functions in their comprehension (i.e., the issue of knowledge availability versus accessibility in Cremer and Schoonen, 2013), not to mention comprehension at different levels. To fill gaps in previous research and enrich our...
Show moreResearchers have investigated that different dimensions of word knowledge (breadth versus depth) may play distinct roles in second language (L2) reading comprehension. Yet, little research has addressed how learners’ efficiency of accessing those dimensions of knowledge functions in their comprehension (i.e., the issue of knowledge availability versus accessibility in Cremer and Schoonen, 2013), not to mention comprehension at different levels. To fill gaps in previous research and enrich our knowledge about the lexical basis of L2 reading comprehension, the present study examined how different dimensions of L2 word knowledge and their respective accessibility function concurrently in explaining different levels of L2 reading comprehension in adolescent English as a Foreign Language (EFL) learners in Korea. To achieve this research goal, the present study defined lexical competence by distinguishing between vocabulary breadth and depth knowledge as well as between knowledge availability and accessibility. A number of tasks were employed to measure participants’ lexical competences: three paper-and-pencil tests for knowledge availability and three researcher-developed, computer-based tests for knowledge accessibility documenting response accuracy as well as latency. Reading comprehension was measured with the Gates-MacGinitie Reading Comprehension Test (MacGinitie & MacGinitie, 1992), which assessed both literal and inferential comprehension. In addition, the participants’ working memory and grammatical knowledge were also measured. The following key research findings were revealed. First, Confirmatory Factor Analysis analyses confirmed that knowledge of individual word meanings (breadth availability) and the ability to activate that knowledge efficiently (breadth accessibility), and knowledge of meaning relations among words (depth availability) and the ability to access that knowledge efficiently (depth accessibility) are distinctive constructs under the conceptualization of lexical competence. Second, availability and accessibility of depth knowledge were the only predictors that made significant contributions to reading comprehension when the impacts of those of breadth knowledge and working memory were controlled for. Within vocabulary depth, availability played a more important role than did accessibility. Availability and accessibility of breadth knowledge made no unique contribution to reading comprehension over and beyond those of depth knowledge. Third, the patterns of predictive roles of each lexical competence in reading comprehension did not seem substantially different between literal and inferential comprehension, confirming a stronger impact of depth knowledge, both availability and accessibility, than of breadth knowledge, and of availability of depth knowledge than of accessibility. However, the involvement of depth knowledge, particularly availability, seemed greater in inferential comprehension than in literal comprehension. These findings enriched our understanding about the lexical basis of L2 reading comprehension, particularly, the importance of efficient access to semantic network knowledge for textual reading and potentially differential involvement of semantic network knowledge in different levels of comprehension. Pedagogically, they suggested that vocabulary instruction should provide a learning environment where new words are provided in a meaningful reading context so that learners can establish a semantic network in their lexicon and continue developing, expanding, and consolidating the lexicon as they learn new words.
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Title: Transparent multijunction organic photovoltaics
Creator: Young, Margaret (Process engineer)
Date: 2017
Collection: Electronic Theses & Dissertations
Description: "The widespread adoption of conventional solar cells based on inorganic semiconductors has been gaining traction in recent years but is still often hindered by high cost and lack of aesthetic appeal. Transparent organic semiconductor-based solar cells that selectively absorb in the UV and the NIR enable integration into building windows, automobiles, and consumer electronics in ways that traditional solar cells cannot. Moreover, integration onto existing infrastructure reduces the racking and...
Show more"The widespread adoption of conventional solar cells based on inorganic semiconductors has been gaining traction in recent years but is still often hindered by high cost and lack of aesthetic appeal. Transparent organic semiconductor-based solar cells that selectively absorb in the UV and the NIR enable integration into building windows, automobiles, and consumer electronics in ways that traditional solar cells cannot. Moreover, integration onto existing infrastructure reduces the racking and installation cost. In this work, we investigate routes to improve the efficiency of transparent solar cells by utilizing multijunction architectures. A transfer-matrix optical interference model is developed as a framework to optimize the full device stack considering the angle-dependent PV performance that is critical for matching subcell photocurrents in series tandem solar cells. In addition, a new method of fine tuning energy levels of low-bandgap small molecules with infrared selective absorption was demonstrated using a series of organic heptamethine salts. By exchanging the counterion from a small, hard anion to a fluorinated weakly coordinating anion, the frontier energy of the salt is shown to shift without affecting the bandgap, thus enabling simultaneous optimization of photocurrent generation of photovoltage. We further utilize this tunability to develop heptamethine molecules with absorption as deep as 1600 nm, the deepest infrared photo-response demonstrated to date with organic small molecules ideal for multijunction integration. Ultimately, transparent solar cells are an exciting new paradigm for solar deployment enabled by organic and excitonic semiconductors that offer a pathway to integrate solar onto virtually any surface without impacting the view."--Page ii.
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Title: Empirical analyses of regional innovation and economic growth in the United States
Creator: Aryal, Giri Raj
Date: 2018
Collection: Electronic Theses & Dissertations
Description: Much of the innovation creation literature is focused on urban firms and areas or relies heavily on data based on these; less studied are rural firms or rural areas in this regard. The goal of this dissertation is to explore the drivers of rural-urban innovation gap and the link between regional innovation and economic growth and propose policies to mitigate regional innovation ecosystem deficiencies and impediments that contribute to the gap. In my first essay, I analyze heterogeneity in...
Show moreMuch of the innovation creation literature is focused on urban firms and areas or relies heavily on data based on these; less studied are rural firms or rural areas in this regard. The goal of this dissertation is to explore the drivers of rural-urban innovation gap and the link between regional innovation and economic growth and propose policies to mitigate regional innovation ecosystem deficiencies and impediments that contribute to the gap. In my first essay, I analyze heterogeneity in inventiveness across urban and rural counties is using a spatial autoregressive negative binomial regression model, considering spatial spillover effects, creative class population, industry characteristics, human capital, and other regional factors influencing innovation. Results indicate that drivers of invention, namely a college-educated labor force and diversity of high-tech industries are common across all counties types, but urban inventive advantage persists due to agglomeration economies, higher number of universities, and higher shares of high-tech firms, professional services and immigrants. Consistent with the creative class hypothesis, population share of college graduates in creative disciplines also positively contributes to inventive output in urban counties. However, the effects of spatial spillovers and mobile phone technology penetration are stronger for rural counties, suggesting that policies promoting rural centers of innovation, technological diversity, and communication infrastructure in rural counties could help mitigate the urban-rural innovation gap. My second essay explores the interdependence between regional innovation and economic growth by accounting for possible endogenous relationships among regional innovation, income growth, employment and population. It draws on data for 3,038 counties in the 48 contiguous states of the United States collected from several publicly available sources for 2009-13. Endogeneity tests using instrumental variable regressions show that regional innovation and economic growth have endogenous relationships. Considering the endogeneity and estimating the system of simultaneous equations for regional innovation and economic growth using three stage least squares (3SLS) method, I find that innovation belongs to system of regional growth. Further, reduced form estimates of the 3SLS results suggest that policies promoting regional clusters of high-tech firms and capitalizing on the knowledge potential of the immigrants are likely to reinforce both regional innovation rates and economic growth. My third essay analyzes the characteristics that potentially influence innovation creation across rural and urban firms employing a survey dataset from 2014 National Survey of Business Competitiveness combined with secondary data reflecting the regional business and innovative environments where these firms operate. The number of patent applications filed by these firms measures their innovation creation, and the paper employs a negative binomial regression estimation for analysis. The findings of this essay show that, after controlling for industry, county and state factors, rural and urban firms differ in their innovation creation characteristics and behaviors, suggesting that urban firms capitalize on their resources better than rural firms. Other major findings of the essay provide evidence that (i) for rural firms, the influence of university R&D is relevant to innovation creation, but their perception of university provided information is not significant and (ii) rural firms that are willing to try, but fail, in terms of innovation creation have a slight advantage over other rural firms less willing to take on the risk.
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Title: EFFECT OF GATE-OXIDE DEGRADATION ON ELECTRICAL PARAMETERS OF SILICON AND SILICON CARBIDE POWER MOSFETS
Creator: KARKI, UJJWAL
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is recognized as a crucial component of many power-electronic systems. The physical structure of both Silicon and Silicon Carbide power MOSFETs require an oxide layer as a dielectric material between their gate terminal and the semiconductor surface. The gate-oxide material, which is predominantly silicon dioxide, slowly degrades under the presence of an electric field. Over time, the degradation process significantly alters...
Show moreThe power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is recognized as a crucial component of many power-electronic systems. The physical structure of both Silicon and Silicon Carbide power MOSFETs require an oxide layer as a dielectric material between their gate terminal and the semiconductor surface. The gate-oxide material, which is predominantly silicon dioxide, slowly degrades under the presence of an electric field. Over time, the degradation process significantly alters the electrical parameters of power MOSFETs, causing a negative impact on performance, reliability, and efficiency of power converters they are used in. In order to monitor this, the electrical parameters are utilized as precursors (or failure indicators) of gate-oxide degradation.Despite extensive investigation of gate-oxide degradation in Silicon (Si) power MOSFETs, the research literature has not attributed a consistent variation pattern to its gate-oxide degradation precursors. This dissertation investigates the variation pattern of existing precursors: a) threshold voltage, b) gate-plateau voltage, and c) on-resistance. While confirming the previously reported dip-and-rebound variation pattern of the threshold voltage and the gate-plateau voltage, a similar dip-and-rebound variation pattern is also identified in the on-resistance of Si power MOSFETs. Furthermore, a new online precursor of gate-oxide degradation— the gate-plateau time, is proposed and demonstrated to exhibit a similar dip-and-rebound variation pattern. The gate-plateau time is also shown to be the most sensitive online precursor for observing the rebound phenomenon. In addition, the analytical expressions are derived to correlate the effect of gate-oxide degradation with simultaneous dip-and-rebound variation pattern in all four precursors. The dip-and-rebound variation pattern is experimentally confirmed by inducing accelerated gate-oxide degradation in two different commercial Si power MOSFETs. While multiple electrical parameters have been identified as precursors for monitoring the gate-oxide degradation in Si MOSFETs, very few precursors have been proposed for Silicon Carbide (SiC) power MOSFETs. This dissertation proposes that in addition to the threshold voltage, the other online precursors identified for Si power MOSFETs: the gate-plateau voltage and the gate-plateau time, are also effective for monitoring the effect of gate-oxide degradation process in SiC power MOSFETs. Though the gate-oxide material is the same in both Si and SiC power MOSFETs, the effect of gate-oxide degradation on the variation pattern of electrical parameters is different. In contrast to the dip-and-rebound variation pattern of precursors in Si MOSFETs, the research literature has attributed a consistent linear-with-log-stress-time variation pattern to the threshold-voltage shift in SiC power MOSFETs. It is shown that both the gate-plateau voltage and the gate-plateau time increase in a linear-with-log-stress-time manner similar to the threshold voltage. The analytical expressions are derived to correlate the effect of gate-oxide degradation with simultaneous linear-with-log-stress-time variation pattern in all three online precursors. The increasing trend of precursors is experimentally confirmed by inducing accelerated gate-oxide degradation in both planar and trench-gate commercial SiC power MOSFETs under high voltage, high temperature, and hard-switching conditions.
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Title: Through experiences, from interactions, and by choices over time : how professors at a research university understand and explain the factors that have influenced their teaching
Creator: Steele, Gregory John
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The intent of this study was to understand professors at a research university, and how the environments and individuals they interact with influenced them and their teaching. The primary research question for this study was, "How do professors at a research university understand and explain the factors that have influenced their teaching?" The secondary research question was intended to focus on the institutional factors that had the most influence on a professor and their teaching: "What...
Show moreThe intent of this study was to understand professors at a research university, and how the environments and individuals they interact with influenced them and their teaching. The primary research question for this study was, "How do professors at a research university understand and explain the factors that have influenced their teaching?" The secondary research question was intended to focus on the institutional factors that had the most influence on a professor and their teaching: "What are the most influential factors that affect a professor's teaching at a research institution?"I interviewed 15 award-winning professors from Michigan State University (MSU) about how they had been prepared, supported, and recognized for their work as teachers. My analysis showed how little preparation the professors received about teaching at a research university, how they relieved more on experience and trusted peers than any of the available campus resources, and how they tended to find personal student recognition more rewarding than their prestigious teaching awards. My results showed how institutional deficiencies (the lack teaching preparation, applicable resources, and sufficient recognition) created obstacles for the professors to overcome as they progressed and developed as teachers. To lessen or remove the institutional obstacles, I recommend research universities better assess and recognize a professor's teaching, faculty developers localize their available resources to the individual colleges and departments, and professors utilize their peers and self-reflection as a way to meet their needs and expectations as teachers. Professors at research universities are expected to prioritize their teaching and scholarship, but the importance of the former can become complicated when institutions place a greater emphasis on the latter (via the tenure process, promotions, raises, and rewards). This study extends previous scholarship which shows that professors at research universities are not sufficiently prepared, supported, or recognized for their work as teachers. If the individual institutions do not properly prepare their professors as teachers, then there is uncertainty as to how, where, and why the individual professors succeed and develop as teachers.
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Title: Microwave Imaging Using a Tunable Reflectarray Antenna and Superradiance in Open Quantum Systems
Creator: Tayebi, Amin
Date: 2017
Collection: Electronic Theses & Dissertations
Description: Theory, experiment, and computation are the three paradigms for scientific discoveries. This dissertation includes work in all three areas. The first part is dedicated to the practical design and development of a microwave imaging system, a problem mostly experimental and computational in nature. The second part discusses theoretical foundations of possible future advances in quantum signal transmission. In part one, a new active microwave imaging system is proposed. At the heart of this...
Show moreTheory, experiment, and computation are the three paradigms for scientific discoveries. This dissertation includes work in all three areas. The first part is dedicated to the practical design and development of a microwave imaging system, a problem mostly experimental and computational in nature. The second part discusses theoretical foundations of possible future advances in quantum signal transmission. In part one, a new active microwave imaging system is proposed. At the heart of this novel system lies an electronically reconfigurable beam-scanning reflectarray antenna. The high tuning capability of the reflectarray provides a broad steering range of +\- 60 degrees in two distinct frequency bands: S and F bands. The array, combined with an external source, dynamically steers the incoming beam across this range in order to generate multi-angle projection data for target detection. The collected data is then used for image reconstruction by means of time reversal signal processing technique. Our design significantly reduces cost and operational complexities compared to traditional imaging systems. In conventional systems, the region of interest is enclosed by a costly array of transceiver antennas which additionally requires a complicated switching circuitry. The inclusion of the beam scanning array and the utilization of a single source, eliminates the need for multiple antennas and the involved circuitry. In addition, unlike conventional setups, this system is not constrained by the dimensions of the object under test. Therefore the inspection of large objects, such as extended laminate structures, composite airplane wings and wind turbine blades becomes possible. Experimental results of detection of various dielectric targets as well as detecting anomalies within them, such as defects and metallic impurities, using the imaging prototype are presented.The second part includes the theoretical consideration of three different problems: quantum transport through two different nanostructures, a solid state device suitable for quantum computing and spherical plasmonic nanoantennas and waveguides. These three physically different systems are all investigated within a single quantum theory; the effective non-Hermitian Hamiltonian framework. The non-Hermitian Hamiltonian approach is a convenient mathematical formalism for the description of open quantum systems. This method based on the Feshbach projection formalism provides an alternative to popular methodssuch as the Feynman diagrammatic techniques and the master equation approach that are commonly used for studying open quantum systems. It is formally exact but very flexible and can be adjusted to many specific situations. One bright phenomenon emerging in the situation with a sufficiently strong continuum coupling in the case when the number of open channels is relatively small compared to the number of involved intrinsic states is the so-called superradiance. Being an analog of superradiance in quantum optics, this term stands for the formation in the system of a collective superposition of the intrinsic states coherently coupled to the same decay channel. The footprint of superradiance in each system is investigated in detail. In the quantum transport problem, signal transmission is greatly enhanced at the transition to superradiance. In the proposed solid state based charge qubit, the superradiant states effectively protect the remaining internal states from decaying into the continuum and hence increase the lifetime of the device. Finally, the superradiance phenomenon provides us a tool to manipulate light at the nanoscale. It is responsible for the existence of modes with distinct radiation properties in a system of coupled plasmonic nanoantennas: superradiant states with enhanced and dark modes with extremely damped radiation. Furthermore, similar to the quantum case, energy transport through a plasmonic waveguide is greatly enhanced.
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Title: "Take action in the world!" : advocacy and reciprocity as research practices in technical communication
Creator: Turner, Heather Noel
Date: 2018
Collection: Electronic Theses & Dissertations
Description: This dissertation examines how scholars in technical and professional communication conduct research related to social justice. I define social justice research, then identify and visualize disciplinary activity related to social justice over a 10 year (2006-2016) time span. Using data visualizations and critical computations as a methodological heuristic, I present the practices of four scholars conducting social justice research to offer thematic data narratives. I found that scholars can...
Show moreThis dissertation examines how scholars in technical and professional communication conduct research related to social justice. I define social justice research, then identify and visualize disciplinary activity related to social justice over a 10 year (2006-2016) time span. Using data visualizations and critical computations as a methodological heuristic, I present the practices of four scholars conducting social justice research to offer thematic data narratives. I found that scholars can enact social justice when they intentionally integrate principles of advocacy and reciprocity across the arcs of their research processes. Advocacy occurs when researchers negotiate, accommodate and facilitate justice across research settings, throughout research processes, and with research partners. Reciprocity occurs when researchers structure opportunities to exchange knowledge, labor, and resources with participants and related peoples, communities, organizations, and nonprofits. The data from 960 conference presentations and four semi-structured interviews with technical communication researchers reveals that technical communication as a field has commitments to inclusion, public action, and increasing individual agency. Social justice researchers enact these commitments through their research processes, across research contexts, and with various research partners.
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Title: A detailed study of the gamma-ray nova V1324 Sco
Creator: Finzell, Thomas Michael Broen
Date: 2017
Collection: Electronic Theses & Dissertations
Description: It has recently been discovered that some, if not all, classical novae emit GeV gamma-rays, but the mechanisms involved in the production of the gamma-rays are still not well understood. We present here a comprehensive, multi-wavelength dataset---from radio to X-rays---for the most gamma-ray luminous classical nova to-date, V1324 Sco. Using this dataset, we show that V1324 Sco is a canonical dusty Fe-II type nova, with a reddening of E(B-V) = 1.16 +\- 0.12, a distance > 6.5 kpc, a bulk ejecta...
Show moreIt has recently been discovered that some, if not all, classical novae emit GeV gamma-rays, but the mechanisms involved in the production of the gamma-rays are still not well understood. We present here a comprehensive, multi-wavelength dataset---from radio to X-rays---for the most gamma-ray luminous classical nova to-date, V1324 Sco. Using this dataset, we show that V1324 Sco is a canonical dusty Fe-II type nova, with a reddening of E(B-V) = 1.16 +\- 0.12, a distance > 6.5 kpc, a bulk ejecta velocity of 1150 +/- 40 km/s and an ejecta mass of 2.0 +\- 0.4 * 10^-5 M_{Solar}. However, despite its seeming normalcy, there is also evidence for complex shock interactions, including the aforementioned gamma-rays and early time high-brightness temperature radio emission. To explain how a nova can be simultaneously ordinary and have the highest gamma-ray luminosity to date, we present a simplified model of the ejecta in which the strength of gamma-ray emission is set by properties of a fast ejecta component that collides with a slower component to produce shocks. We conclude this detailed study of V1324 Sco by showing how it has helped shape our understanding of the role of shocks in novae. Along with the study of V1324 Sco, this work also presents detailed methods for determining the reddening, distance, and filling factor of a classical nova from optical spectroscopy (using V1324 Sco as an example). We also provide detailed derivations for fitting nova radio light curves, to determine ejecta mass and velocity.
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Title: Prime torsion in the Brauer group of an elliptic curve
Creator: Ure, Charlotte
Date: 2019
Collection: Electronic Theses & Dissertations
Description: The Brauer group is an invariant in algebraic geometry and number theory, that can be associated to a field, variety, or scheme. Let k be a field of characteristic different from 2 or 3, and let E be an elliptic curve over k. The Brauer group of E is a torsion abelian group with elements given by Morita equivalence classes of central simple algebras over the function field k(E). The Merkurjev-Suslin theorem implies that any such element can be described by a tensor product of symbol algebras....
Show moreThe Brauer group is an invariant in algebraic geometry and number theory, that can be associated to a field, variety, or scheme. Let k be a field of characteristic different from 2 or 3, and let E be an elliptic curve over k. The Brauer group of E is a torsion abelian group with elements given by Morita equivalence classes of central simple algebras over the function field k(E). The Merkurjev-Suslin theorem implies that any such element can be described by a tensor product of symbol algebras. We give a description of elements in the d-torsion of the Brauer group of E in terms of these tensor products, provided that the d-torsion of E is k-rational and k contains a primitive d-th root of unity. Furthermore, if d = q is a prime, we give an algorithm to compute the q-torsion of the Brauer group over any field k of characteristic different from 2,3, and q containing a primitive q-th root of unity.
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Title: Flexible hierarchical Bayesian modeling extensions to improve whole genome prediction and genome wide association analyses
Creator: Chen, Chunyu (Graduate of Michigan State University)
Date: 2017
Collection: Electronic Theses & Dissertations
Description: "Whole genome prediction (WGP) has been widely implemented in animal and plant breeding for genomic selection of economically important traits, having already accelerated genetic progress for economically important traits in some species especially dairy cattle. Genome wide association (GWA) analysis is used for screening genomic regions that may include important candidate genes segregating for the trait of interest and is being increasingly integrated with WGP analysis. Both WGP and GWA...
Show more"Whole genome prediction (WGP) has been widely implemented in animal and plant breeding for genomic selection of economically important traits, having already accelerated genetic progress for economically important traits in some species especially dairy cattle. Genome wide association (GWA) analysis is used for screening genomic regions that may include important candidate genes segregating for the trait of interest and is being increasingly integrated with WGP analysis. Both WGP and GWA typically represent m226Bn problems as defined by a large number of single nucleotide polymorphism (SNP) markers (m) and comparably much smaller number of individuals (n). Two broad types of parametric models are typically considered for these analyses: traditional best linear unbiased prediction approaches based on SNP marker effects being normally distributed and Bayesian WGP models that allow more flexible specifications for SNP marker effects based on either heavy-tailed or variable selection specifications. Bayesian WGP models can achieve higher prediction accuracies than traditional approaches in many applications if properly tuned; however, their implementation can be computationally challenging. My dissertation was aimed to address some of these emerging issues in Bayesian WGP models as well as providing software tools for real data applications. In Chapter 2, I developed an expectation maximization (EM) algorithm as a fast alternative to traditional Markov Chain Monte Carlo (MCMC) for Bayesian WGP models. I proposed EM implementations for two models, heavy-tailed BayesA and stochastic search and variable selection (SSVS) adapting the EM algorithm for maximum a posterior (MAP) inference of SNP effects and adapting REML like strategies to estimate key hyperparameters. Using a comprehensive simulation study and real data analysis, I found that these empirical Bayes approaches can be quite sensitive to starting values for SNP effects. However, using a deterministic annealing variant of EM, I obtained hyperparameter estimates and prediction accuracies comparable to their MCMC counterparts. In Chapter 3, I further assessed the possibility using two Bayesian WGP models BayesA and SSVS for GWA studies. I also included a popular GWA analysis (EMMAX) based on the utilization of the linear mixed model. In addition to basing inferences on traditional single SNP tests and fixed genomic window tests, I assessed the merit of tests involving adaptively determined windows based on clustering genome into blocks based on linkage disequilibrium. I found that SSVS and BayesA under MCMC and adaptive window tests led to best receiver operating curve (ROC) properties. In Chapter 4, I extended SSVS to single step SSVS to incorporate phenotypes of non-genotyped individuals and compared its performance with corresponding models ignoring these genotypes for both WGP and GWA. I found single step SSVS to be a promising for WGP and GWA, particularly for genetic architectures characterized by a few genes with large effects. In Chapter 5, I combined much of the developments in Chapter 2 to Chapter 4 and beyond in a unified framework as an open source R package BATools to implement several different Bayesian models for WGP and GWA."--Pages ii-iii.
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