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Investigating The Complexity Of Impact Crater Ejecta, Michael Raymond Zanetti

Arts & Sciences Graduate Student Theses and Dissertations

The formation of an impact crater ejecta blanket can be viewed as a form of organized chaos. Material that is ejected from a crater is heavily brecciated, but falls back to the surface along ballistic trajectories, generally preserving an inverted sense of the original stratigraphy. As the ejecta re-impacts the area surrounding the crater it forms a thick blanket of ejected material and reworked target surface that gradually thins away from the crater rim. Within the crater, crater modification processes, such as wall terrace formation and impact melt drainage, transform the crater in expectable ways. The approach adopted in this …

Identifying The Origin Of Galactic Cosmic Rays With The Supertiger Instrument, Ryan Patrick Murphy

Arts & Sciences Graduate Student Theses and Dissertations

The SuperTIGER (Trans-Iron Galactic Element Recorder) experiment was launched on a long-duration balloon flight from Williams Field, Antarctica, on December 8, 2012. The instrument measured the relative elemental abundances of galactic cosmic rays (GCR) in the charge (Z) range Z>10 with excellent charge resolution, displaying well resolved individual element peaks for 10 ≤ Z ≤ 40. During its record-breaking 55-day flight, SuperTIGER collected ~4.15 x10^6 Iron nuclei, ~ 7.5 times as many as detected by its predecessor, TIGER, with charge resolution at iron of < 0.18 cu. SuperTIGER measures charge (Z) and energy (E) using a combination of three scintillator and two Cherenkov detectors, and employs a scintillating fiber hodoscope for event trajectory determination. The SuperTIGER data have been analyzed to correct for instrument effects and remove events that underwent nuclear interactions within the instrument. The data include more than 600 events in the charge range 30 < Z ≤ 40. SuperTIGER is the first experiment to resolve elemental abundances in this charge range with single-element resolution and high statistics. The relative abundances of the galactic cosmic ray source have been derived using atmospheric and interstellar propagations of the measured relative elemental abundances. The SuperTIGER measured abundances are generally consistent with previous experimental results from TIGER and ACE-CRIS, with improved statistical precision. The SuperTIGER results confirm the earlier results from TIGER, supporting a model of cosmic-ray origin in OB associations, with preferential acceleration of refractory elements over volatile elements ordered by atomic mass (A).

Behavioral And Fmri-Based Characterization Of Cognitive Processes Supporting Learning And Retrieval Of Memory For Words In Young Adults, Binyam Nardos

Arts & Sciences Graduate Student Theses and Dissertations

A novel word is rarely defined explicitly during the first encounter. With repeated exposure, a decontextualized meaning of the word is integrated into semantic memory. With the overarching goal of characterizing the functional neuroanatomy of semantic processing in young adults, we employed a contextual word learning paradigm, creating novel synonyms for common animal/artifact nouns that, along with additional real words, served as stimuli for the lexical-decision based functional MRI (fMRI) experiment. Young adults (n=28) were given two types of word learning training administered in multiple sessions spread out over three days. The first type of training provided perceptual form-only training …

Human Immunodeficiency Virus Type 1 Envelope Protein Interaction With Host Cell Coreceptor C-X-C Chemokine Receptor Type 4, Jie Zhang

Arts & Sciences Graduate Student Theses and Dissertations

Human Immunodeficiency Virus Type 1 (HIV-1) envelope protein is the sole determinant for viral entry and tropism. The ability of HIV-1 to infect susceptible host cells depends on the ability of its envelope protein to engage host cell receptor CD4 and coreceptor C-C Chemokine Receptor Type 5 (CCR5) and/or C-X-C Chemokine Receptor Type 4 (CXCR4). Most naturally occurring infections start with a single CCR5-tropic virion. In approximately 50% of HIV-1 Clade B infected patients, the viral population spontaneous develops the ability to utilize CXCR4 at a late disease stage, and this coreceptor shift corresponds to a poor prognosis for the …

The Identification Of Alkaloid Pathway Genes From Non-Model Plant Species In The Amaryllidaceae, Matthew B. Kilgore

Arts & Sciences Graduate Student Theses and Dissertations

Secondary metabolites are often restricted in their distribution to different groups of organisms. For this reason, attempts to study these often useful and interesting products of metabolism require an ability to work in a diversity of non-model species. Methods for gene discovery with low investment and high efficiency are needed to effectively identify the biosynthetic genes in these diverse pathways. During this work, a workflow for efficiently identifying biosynthetic genes was developed and applied to Amaryllidaceae alkaloid biosynthesis. Genes discovered during this work include a norbelladine 4’-O-methyltransferase, a cytochrome P450 capable of phenol-phenol coupling 4’-O-methylnorbelladine to noroxomaritidine, and a short-chain …

The Mechanism And Regulation Of Mammalian Photoreceptor Dark Adaptation, Yunlu Xue

Arts & Sciences Graduate Student Theses and Dissertations

The visual perception of vertebrates begins in rod and cone photoreceptors. Both photoreceptors require visual pigments to detect light. At the first step of light detection, a chromophore molecule (i.e. 11-cis retinal), which is conjugated to the visual pigment in photoreceptor outer segment, absorbs a photon. Photoisomerization of the chromophore activates the visual pigment, triggers the phototransduction cascade, and produces electrical signals. After photoisomerization, the chromophore is ultimately converted to all-trans retinol, which must be recycled to regenerate the visual pigment. This visual pigment regeneration process is called the visual cycle. It is the rate-limiting step of the photoreceptor dark …

Applying Bayesian Machine Learning Methods To Theoretical Surface Science, Shane Carr

McKelvey School of Engineering Graduate Student Theses & Dissertations

Machine learning is a rapidly evolving field in computer science with increasingly many applications to other domains. In this thesis, I present a Bayesian machine learning approach to solving a problem in theoretical surface science: calculating the preferred active site on a catalyst surface for a given adsorbate molecule. I formulate the problem as a low-dimensional objective function. I show how the objective function can be approximated into a certain confidence interval using just one iteration of the self-consistent field (SCF) loop in density functional theory (DFT). I then use Bayesian optimization to perform a global search for the solution. …

Copper And Zinc Oxide Composite Nanostructures For Solar Energy Harvesting, Fei Wu

McKelvey School of Engineering Graduate Student Theses & Dissertations

Solar energy is a clean and sustainable energy source to counter global environmental issues of rising atmospheric CO2 levels and depletion of natural resources. To extract useful work from solar energy, silicon-based photovoltaic devices are extensively used. The technological maturity and the high quality of silicon (Si) make it a material of choice. However limitations in Si exist, ranging from its indirect band gap to low light absorption coefficient and energy and capital intensive crystal growth schemes. Therefore, alternate materials that are earth-abundant, benign and simpler to process are needed for developing new platforms for solar energy harvesting applications.

In …

Science And Nature In The Medieval Ecological Imagination, Jessica Rezunyk

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation explores the intersections between nature and culture in medieval literature and art with particular focus on Geoffrey Chaucer’s House of Fame, the thirteenth-century French Bible Moralisée (Vienna, Österreichische Nationalbibliothek Codex Vindobonensis 2554), and William Langland’s Piers Plowman. Current academic paradigms tend to place the study of nature firmly within the sciences and the study of culture firmly within the humanities, creating a gap between the fields that effectively isolates their respective methodologies and vocabularies from one another. This dissertation seeks to bridge that gap between the sciences and the humanities by approaching medieval literature through the lens of …

Investigation Of 89zr-Siderophores As Molecular Imaging Agents For Positron Emission Tomography Imaging Of Bacterial Infections, Nora C. M. Goscinski

Arts & Sciences Graduate Student Theses and Dissertations

Siderophores are small molecules synthesized by bacteria to harvest Fe³⁺ from their environment. In infection scenarios, their production can increase infection virulence by increasing the ability of bacteria to obtain Fe³⁺ and therefore grow more rapidly. The selective uptake of siderophores in vivo in multi-bacteria environments indicates that this class of molecules has a potential use as selective imaging agents. In this work, DFO-NCS and a library of trihydroxamate siderophores were evaluated as vehicles to deliver ⁸⁹Zr selectively to bacteria for Positron Emission Tomography (PET) imaging of bacterial infections. Productive work with radiometals involves thorough knowledge of …

Functional Consequences Of Cantu Syndrome Associated Mutations In The Atp Sensitive Potassium Channel, Paige Cooper

Arts & Sciences Graduate Student Theses and Dissertations

ATP-sensitive potassium (KATP) channels are composed of inward-rectifying potassium channel pore-forming subunits (Kir6.1 and Kir6.2, encoded by KCNJ8 and KCNJ11, respectively) and regulatory sulfonylurea receptor subunits (SUR1 and SUR2, encoded by ABCC8 and ABCC9, respectively). These channels couple metabolism to excitability in multiple tissues. Mutations in ABCC9 have been linked to Cantú syndrome (CS), a multi-organ disease characterized by congenital hypertrichosis, distinct facial features, osteochondrodysplasia, and cardiac defects. Additionally, two ABCC9 mutation-negative patients, exhibiting clinical hallmarks of CS, have been identified as having KCNJ8 mutations. This body of work is focused on determining the functional consequences and molecular mechanisms of …

Transcriptional Regulation Of The Endoplasmic Reticulum In Dedicated Secretory Cells, Benjamin David Moore

Arts & Sciences Graduate Student Theses and Dissertations

Differentiating cells express subsets of genes to build the cellular machinery necessary to perform their specific function as they acquire their mature fate. These subsets of genes are regulated by networks of transcription factors as cells progress through their developmental program. In secretory tissue, highly-specialized cells establish a complex secretory apparatus and scale up their cellular architecture to facilitate the production and secretion of large amounts of protein. Here, we identify a network of transcription factors responsible for the development of this cellular machinery in these professional secretory cells, and develop new tools to better study the molecular networks that …

Optimization Of Looped Airfoil Wind Turbine (Lawt) And Looped Airfoil Hydro-Turbine (Laht) Design Parameters For Maximum Power Generation, Binhe Song

McKelvey School of Engineering Graduate Student Theses & Dissertations

This focus of this research is on the study of the aerodynamic performance of a Looped Airfoil Wind Turbine (LAWT™) using the Computational Fluid Dynamics (CFD) software. The looped airfoil wind turbine (LAWT™) is a patented new technology by EverLift Wind Technology, Inc. for generating power from wind. It takes advantage of the superior lift force of a linearly traveling wing compared to the rotating blades in conventional wind turbine configurations. Compared to horizontal and vertical axis wind turbines, the LAWT™ can be manufactured with minimal cost because it does not require complex gear systems and its blades have a …

Thermally Evolved & Separated Composition Of Atmospheric Aerosols: Development And Application Of Advanced Data Analysis Techniques For A Thermal Desorption Aerosol Gas Chromatograph (Tag), Yaping Zhang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Atmospheric organic aerosols are composed of thousands of individual compounds, interacting with climate through changes in aerosol optical properties and cloud interactions, and can be detrimental to human health. Aerosol mass spectrometry (MS) and gas chromatography (GC)-separated MS measurements have been utilized to better characterize the chemical composition of this material that comes from a variety of sources and experiences continuous oxidation while in the atmosphere. This dissertation describes the development of a novel rapid data analysis method for grouping of major components within chromatography-separated measurements and first application using thermal desorption aerosol gas chromatograph (TAG) – MS data. Chromatograms …

Structural Evolution, Chemical Order, And Crystallization Of Metallic Liquids And Glasses, Mark Johnson

Arts & Sciences Graduate Student Theses and Dissertations

Over the last 60 years, bulk metallic glasses have emerged as a new class of materials with highly desirable material properties. Their high strength, high elasticity, and corrosion resistance are attractive properties for viable commercial products. At its core, material properties are directly related to the underlying microstructure. By understanding the structural and chemical order in the liquid and undercooled liquid and their relationship to thermophysical properties such as viscosity, a greater understanding of bulk metallic glass formation can be achieved. In this dissertation, electrostatic levitation techniques are used to study the liquid in a containerless environment using a combination …

The Role Of Trauma And Mental Health Problems In The Perpetration Of Intimate Partner Violence In Post-Genocide Rwanda, Sarah Myers Tlapek

Arts & Sciences Graduate Student Theses and Dissertations

Exposure to political violence or war is associated with intimate partner violence (IPV) in post-conflict settings (Clark et al., 2010; Gupta, Reed, Kelly, Stein, & Williams, 2012), and civilians and veterans who develop posttraumatic stress disorder (PTSD) after exposure to combat or violence are more likely to perpetrate violence against an intimate partner (Taft, Watkins, Stafford, Street, & Monson, 2011). Rwandan health professionals estimate that after the 1994 genocide more than one-quarter of the country’s population now suffers from PTSD (Munyandamutsa, Nkubamugisha, Gex-Fabry, & Eytan, 2012). Although the majority of Rwandan women (56%) have experienced IPV in their lifetime (National …

National Narratives, Comparative Moves: Tracing Literary Connections Between Anglophone Postcolonial Literatures And Modern Turkish Literature, Aysegul Turan

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation examines Anglophone postcolonial literatures and modern Turkish literature through their representations of the idea of empire and the nation-state. By employing a comparative framework that brings together Anglophone postcolonial literatures and modern Turkish literature, this project strives to relocate the focus of postcolonial discourse from the colonizer-colonized divide to a broader frame of uneven power relations, both past and present. In doing so, it examines paradigms such as the independence struggle, the nation-state, and modernization that are vital to an understanding not only of the imperial past but also of the global present. The Anglophone postcolonial canon and …

Molecular Mechanisms Of Axon Growth And Regeneration, Dana Watt

Arts & Sciences Graduate Student Theses and Dissertations

Neurons are cells with unique and extremely polarized morphologies. The axon allows communication between the cell soma and the distantly located synaptic terminal and can extend up to one meter in humans. This exceptional cellular structure therefore has specialized biological processes dedicated to its growth, maintenance and regeneration. The structure that carries out axon elongation during development and regeneration is the growth cone, which features a cytoskeletal structure that is both highly dynamic yet consistent in overall organization. The growth cone coordinates a leading edge of dynamic actin with the microtubules of the growing axon, enabling directed outgrowth while maintaining …

Betting On Empire: A Socio-Cultural History Of Gambling In Late-Qing China, En Li

Arts & Sciences Graduate Student Theses and Dissertations

This dissertation uses the practice and licensing of gambling, especially the lotteries, to investigate social, intellectual, and geo-political changes in the transitional period of late-Qing China. This research begins with a study of a civil service examination scandal in 1885. A highly organized lottery scheme, where money was bet on surnames that would pass the state’s official selection examinations, spurred manipulation of the examination results. Based on current sources and agreeing with resent studies on public institutions in late-imperial China, I conclude that, the lottery contributed to a more inclusive public by providing people with simultaneous experiences across time and …

Quaternary Chronology And Stratigraphy Of Mickey Springs, Oregon, Leslie Allen Mowbray

Dissertations and Theses

Mickey Springs in the Alvord Desert, southeast Oregon, is analogous to other Basin and Range hydrothermal systems where the requisite conditions of heat source and permeable pathways are met through crustal thinning due to normal faulting. This study examines the morphology and lifespan of near-surface spring features through use of ground penetrating radar, thermoluminescence (TL) dating, and elevation modeling. Duration of hydrothermal activity at Mickey Springs has not previously been determined, and age determinations of sinter at the site are conflicting. The reason for and timing of this change in silica saturation in the hydrothermal fluid has not been resolved. …

Using Guided Math And Flipped Learning In A Fifth Grade Fractions Unit, Kristin Leigh Moore

School of Education and Leadership Student Capstone Theses and Dissertations

The research question addressed in this project was: How can I design a math curriculum that will increase fifth grade students’ understanding of fraction concepts? The author began her research by investigating the struggles elementary students face when learning fraction concepts, which led to a study of four instructional strategies: ability grouping, differentiation, flipped learning, and guided math. The author considered the work of Boaler, Sammons, Tomlinson, Tucker, and Vann to inform her research. After careful reflection on the benefits and limitations of each strategy, the author chose to create a hybrid unit utilizing both guided math and flipped learning. …

Journey To Inclusion: A School’S Perspective From Self-Contained Ecse Classrooms To Inclusive Preschool Programs, Allison Marie Hirsch

School of Education and Leadership Student Capstone Theses and Dissertations

The research question addressed in this project was, How can a school effectively transition from a self-contained Early Childhood Special Education classroom to a full inclusion preschool program? What I have done in this capstone is set out with the objective of defining what is a successful inclusive preschool program, what are the best strategies for these programs, the benefits and barriers to the programs and how to best implement these programs into a school setting. This study details questions and answers from parents and teachers who are currently part of a full-inclusion preschool program.

Engineering A Healthier Watershed: Middle School Students Use Engineering Design To Lessen The Impact Of Their Campus' Impervious Surfaces On Their Local Watershed, Elizabeth Claire Gardner

Dissertations and Theses

It is important that students understand not only how their local watershed functions, but also how it is being impacted by impervious surfaces. Additionally, students need experience exploring the scientific and engineering practices that are necessary for a strong STEM background. With this knowledge students can be empowered to tackle this real and local problem using engineering design, a powerful practice gaining momentum and clarity through its prominence in the recent Framework for K-12 Science Education. Twenty classes of suburban sixth-graders participated in a new five-week Watershed Engineering Design Unit taught by their regular science teachers. Students engaged in scientific …

Using Landsat Tm Imagery To Monitor Vegetation Change Following Flow Restoration To The Lower Owens River, California, Lesley Crandell Bross

Dissertations and Theses

Rehabilitating river corridors to restore valuable riparian habitat consumes significant resources from both governments and private companies. Given these considerable expenditures, it is important to monitor the progress of such projects. This study evaluated the utility of using Landsat Thematic Mapper remotely-sensed data from 2002 and 2009 to monitor vegetation change induced by instream flow restoration to the Lower Owens River in central California. This study compared the results of an unsupervised classification with an NDVI threshold classification to appraise the resources required and effectiveness of each analysis method. The results were inspected by creating standard remote sensing accuracy error …

Isn’T Citizen Science A Hoot? A Case-Study Exploring The Effectiveness Of Citizen Science As An Instrument To Teach The Nature Of Science Through A Local Nocturnal Owl-Monitoring Project, Tess Marie Kreofsky

Dissertations and Theses

Citizen science projects present a distinctive opportunity for professional and volunteer scientists to coordinate their efforts to gather unique sets of data that can benefit the scientific and local communities. These projects are assumed to be an effective educational tool to teach nature of science (NOS) to participants (Brossard, Lewenstein, Bonney, 2005). This case study evaluates the effectiveness of participation in a citizen science project as a way to learn about NOS. Through enhancement of the Tryon Creek Owl Monitoring Project the researcher reviewed the characteristics of a citizen science project that were thought to be necessary to impact the …

Soundboard Scholar No. 1: Editor's Letter, Thomas Heck

Soundboard Scholar

An introduction to the aims and scope of this new scholarly journal of the guitar, and an introduction to the individual articles.

Negotiating Tesol Discourses And Efl Teaching Contexts In China: Identities And Practices Of International Graduates Of A Tesol Program, Roumiana Ilieva, Aojun Li, Wanjun Li

Comparative and International Education / Éducation Comparée et Internationale

This article reports on a study of the material effects of the discourses circulating in a TESOL program housed in a Canadian university on the professional identities and practices that international graduates of the program negotiate and develop in their local professional contexts in China. The principal researcher and two of the study participants discuss pedagogical values salient among program graduates and explore complexities accompanying professional identity negotiation. The article offers recommendations for TESOL programs in affording EFL teachers the possibility to construct hybrid professional identities and dwell comfortably in a “third space” as educational practitioners in a globalized world.

Comparison Of Beginning Teachers' And Experienced Teachers' Readiness To Integratetechnology As Measured By Tpack Scores, Heather S. Fontanilla

Dissertations

Despite a growing awareness of the importance of technology in education, increased investment and attention to preparing teachers to integrate technology into the classroom, research shows that technology continues to fail to live up to its potential for transforming education. As schools move from standards based testing to implementation of the Common Core State Standards (CCSS), an expectation exists that teachers will be using technology to transform their teaching practices. There is also an expectation that schools are providing students with 21st century skills, including the use of technology. In exploring the reasons teachers are not using technology effectively, much …

Puerto Rico’S Community Health Centers In A Time Of Crisis, Peter Shin, Jessica Sharac, Marie Nina Luis, Sara J. Rosenbaum

Geiger Gibson/RCHN Community Health Foundation Research Collaborative

In 2014, Puerto Rico’s twenty federally funded community health centers, operating in 71 sites located throughout the Commonwealth, served 330,736 patients, approximately one in ten Commonwealth residents. Compared to other Puerto Rico residents, health center patients are less likely to be insured. Despite considerable growth in Medicaid as a result of the supplemental funding provided under the Affordable Care Act, in 2014, 12.2% of health center patients remained uninsured.

Compared to health centers outside Puerto Rico, Puerto Rico’s health centers show a greater proportion of Medicaid patients served (69% compared to 46% outside Puerto Rico), a greater dependence on physician …

Curricular Affairs Committee Minutes December 14, 2015, University Of Rhode Island Faculty Senate

Faculty Senate Committee Reports and Appendices

No abstract provided.