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Investigation of Rarefaction Wave Driven Rayleigh-Taylor Instability Using Particle Image Velocimetry
No full textMultiple sets of experiments are presented in which an interface between two gases of different densities is acted upon by a rarefaction wave, creating Rayleigh-Taylor instability (RTI). The RTI is then able to develop and be observed through the use of a long test section with clear windows that allows for high-speed video recording. The rarefaction tube, as the apparatus is named, uses a vacuum tank and pump attached to the bottom of the test section. In between the vacuum tank and test section is a diaphragm that is broken using a push solenoid with an attached arrowhead tip once the vacuum tank is evacuated to the appropriate pressure. Two different gases flow into the rarefaction tube from plenums located at the top and bottom of the apparatus. These gases form an interface at a specified location in the test section. A 2D initial perturbation is introduced on the interface to create standing waves along the interface before the diaphragm is broken. Once the diaphragm is pierced, a rarefaction wave propagates upward causing the gas inside the test section to accelerate downward and into the vacuum tank. RTI develops on the interface of the two gases quickly due to the induced high acceleration. Utilizing diagnostic techniques of shadowgraph and particle image velocimetry (PIV), the RTI was visualized to perform analysis on and comparison with previous experiments performed by Robert Morgan [PhD dissertation, University of Arizona, 2014]. The shadowgraph technique was performed using three high speed CMOS cameras which visualized density gradients. The PIV technique used the same three CMOS cameras in a different configuration which imaged scattered laser light from seeded particles. Experiments were conducted with both diagnostic techniques on gas combinations of air/SF6, CO2/SF6 and helium/CO2. The wavelength of the initial perturbation on the interface was varied by changing the forcing frequency of the initial perturbation. For air/SF6 and CO2/SF6, perturbations producing 1.5 and 2.5 wavelengths within the test section were performed, while with helium/CO2 only 1.5 wavelength experiments were performed. With the data from these experiments, circulation, instability height, growth rate, turbulent kinetic energy and Reynolds numbers were found as a function of time for each of the experimental conditions.
Circulation over a ½ wavelength was found to grow roughly quadratically in time, for which a simplified model is presented. Instability heights and growth rates follow expected trends from previous analysis and agree with the findings of Morgan. Non-dimensional instability height was calculated and used to attempt to characterize the transition to turbulence of RTI. Turbulent kinetic energy was found and temporally plotted for air/SF6 and CO2/SF6 gas combinations, providing a detailed look at how turbulence develops in Rayleigh-Taylor unstable interfaces. Reynolds numbers of the Rayleigh-Taylor unstable interface were found with respect to time to attempt to characterize the transition to turbulence
An Analysis of the Sacred Choral Works of Janice Kapp Perry
No full textJanice Kapp Perry (b. 1938) is perhaps the most well-known living composer who is a member of The Church of Jesus Christ of Latter-day Saints, a worldwide Christian denomination of over seventeen million members. The main focus of this study is to document the life and choral works of Janice Kapp Perry. Her estimated total output includes about 3,000 pieces of music. Among these are hundreds of works for solo voice and piano, dozens of pieces for children/children’s choir, twenty sacred choral works, over 500 hymns, and ten cantatas. In order to increase awareness of and appreciation for Perry’s contributions to sacred choral music, I have provided a biography of the composer, a summary of her choral output, a discussion of the compositional processes and distinguishing features of Perry’s works, and a musical analysis of ten representative choral works. The analysis includes an examination of inspiration, text sources, performing forces, form, melody, rhythm, harmony and text-setting
Applications of Carbonate Geochemistry to Orogenic Systems: Examples from the Himalaya and the Hinterland of the North American Cordillera
No full textCarbonate minerals are amongst the most common materials on earth’s surface. They form in marine, lacustrine and terrestrial settings by inorganic and biogenic mechanisms. Therefore, they can be valuable archives of tectonic, climatic and biological process. In this dissertation, which is composed of four manuscripts, I explore the application of carbonate geochemistry to two of the largest orogenic systems on earth, the North American Cordillera and the Himalaya. In Appendix A, I investigate the alteration and preservation of the stable isotopic composition of carbonates in Himalayan foreland deposits. Assessing the preservation of primary isotopic signatures is critical for interpreting data derived from carbonates. Results show that soil carbonate nodules, tooth enamel, aragonitic fossil bivalve shells and possibly fossil tusk and eggshell all retain primary oxygen and carbon isotope composition during burial up to at least 4.5km, but their clumped isotope composition is altered at modest burial depths by exposure to temperatures of ∼100°C for <5Myrs. Carbonate cemented sandstones behave as open systems, allowing either initial cementation at variable depths or early cementation and later open-system alteration, while tooth enamel does not consistently produce realistic body temperatures regardless of sample age or species. The study highlights the susceptibility of carbonates to alteration and the challenge of reconstructing primary temperatures using clumped isotopes.
In Appendix B I expand the dataset of Appendix A to include samples from all major carbonate units in the Himalaya, including the main carbonate bedrock assemblages and floodplain silts from foreland sediments. I also characterize the 87Sr/86Sr ratio of the main carbonate bedrock units. The study shows the alteration patterns of carbonates through lithification, metamorphism, exhumation and reburial. I also demonstrate the use of carbonate isotope geochemistry as a provenance tool and reconstruct a history of carbonate input to the foreland basin in western Nepal, showing a significant increase in the detrital carbonate bedrock component coincident with Lesser Himalayan duplexing. In addition, the study demonstrates that Himalayan carbonates have unusually high 87Sr/86Sr ratios such that their weathering may have played an important role in the increase in seawater 87Sr/86Sr ratios over the past ~40Myrs.
In Appendix C I examine carbonate bedrock samples and calcite veins from the Monitor Range in the Great Basin, Nevada, USA. Carbonate stable isotopes, 87Sr86Sr ratios, and U-Pb dating demonstrate movement of faults in the range between 22-12Ma and precipitation of calcite from deeply circulating meteoric water. Older calcite veins from the range dated to 74-59Ma may be related to pluton emplacement at this time and coincide with silver and gold mineralization in the area. The oxygen isotope composition of water reconstructed from the veins suggests near modern elevation of the mountains for the past 22Myrs. Bedrock in the study area is altered to high temperatures and low oxygen isotope values, possibly resulting from a hydrothermal pulse.
Appendix D expands on the findings from Appendix C, broadening the study area to five other mountain ranges in the Great Basin. The ages of calcite veins from these ranges are consistent with independent constraints on fault motion, including in ranges where Late Cretaceous and Eocene-Oligocene extension occurred. Veins from three of the ranges are likely related to pluton emplacement and hydrothermal flow events, in some cases associated with precious metal deposits. Paleoelevation reconstructions based on the oxygen isotopic composition of the veins are consistent with previous estimates of a >2.7km high plateau in the area since the Late Cretaceous. The study demonstrates that calcite veins can be used to trace episodes of hydrothermal flow, date phases of extension and reconstruct the regional evolution of paleoelvation.Release after 07/14/202
Performing a Cultural Agenda: Women, Opera, and the Politics of Nationhood in 20th-Century Iran
No full textI examine how the genre of opera became intertwined with nation-building in Iran, particularly through Mohammad Reza Pahlavi’s vision of a pivotal "civilizational exchange" between Iran, its ancient past, and the West. Drawing on archival evidence, interviews, and performance history, I argue that opera was actively reimagined in Iran as a symbol of both modernity and national identity. Through the establishment of institutions like Roudaki Hall and events such as the Shiraz Arts Festival (1967-77), opera emerged not only as a state-sponsored spectacle but as a cultural arena where tensions regarding modernity, gender norms and artistic agency were negotiated. In this context, I highlight the significant contributions of women, including Monir Vakili (1923–1983), Fakhereh Saba (1920–2007), and Evelyn Baghcheban (1928–2010), who not only brought opera to life through performance but also established the infrastructure for its institutionalization. Their stories illuminate a broader transformation in women’s artistic agency and the politics of cultural reform in twentieth-century Iran. In tracing this development, I situate opera within Iran’s evolving musical landscape, from the Qajar and early Pahlavi eras to the peak of state-sponsored modernism in the 1960s and 1970s. Ultimately, I suggest that Iran’s operatic history reflects a deeper struggle over modernity, nationalism, and the gendered nature of public cultural life.Release after 05/26/202
‘I’m Not Picking Myself up by My Bootstraps Anymore’: An Exploratory Case Study of Bi+ College Student Success Informed by Queer Failure and Anti-Homonormativity
No full textDespite comprising the largest segment of the LGBTQ+ community, bi+ (e.g., bisexual, pansexual, those attracted to more than one gender) individuals are underrepresented in postsecondary education literature. Likewise, although an abundance of programs and research is sustained to support student success, there is a dearth of scholarship investigating how practitioners and researchers conceptualize it. Thus, the purpose of this single-institution exploratory qualitative case study was to understand how agents of higher education institutions (i.e., students, staff, faculty) define and describe bi+ college student success and how university personnel and structures support and/or inhibit the success of bi+ collegians. This study employed a critical constructivist epistemology in addition to queer failure and anti-homonormativity as theoretical frameworks. I collected data at Mountain State University (pseudonym) via four observations, analyses of four institutional documents, and semi-structured interviews with six bi+ students and four bi+ staff and faculty members who supported student success in their roles. To analyze the data, I utilized method triangulation, and I developed a queered application of three-cycle thematic analysis coding that better aligned with my theoretical foundation and represented the liminality in the data that is central to queerness. In defining bi+ college success, participants perpetuated normative perspectives of student success and defied or queered traditional understandings, describing it as: failing to succeed in normative ways, minorities graduating and making money, economic dominance and vocational success, academic success and degree attainment, identity-dependent and independent growth, safety and queer liberation, disobeying normativity and political activism, palatable campus, community, and societal impacts, and finding queer community. Participants also described factors that supported and/or inhibited bi+ success, including LGBTQ+-inclusive education, shared- and cross-identity solidarity, faculty, staff, and families of origin, administration’s policies and priorities, hate and violence, intersectional oppressions, campus, local, and state climates, financial, health, and other campus resources, and prideful spaces and events. The present study advanced implications for practitioners to think, act, create, and imagine beyond the institution, the nation-state, and normative student success entirely. Likewise, the findings demonstrated the potential for future studies undergirded in queer failure and anti-homonormativity to produce liberatory scholarship
Cardiovascular and Renal Effects of 5-Aminoimidazole-4-Carboxyribonucleoside (AICAR) in the Deoxycorticosterone Acetate (DOCA)-Salt Rat Model of Hypertension
No full textPrevious studies suggest that exercise training mitigates blood pressure in hypertensive animal models. While exercise training is a great therapeutic, many patients diagnosed with hypertension can be noncompliant with lifestyle modifications that involve physical activity or are unable to participate in strenuous activity due to the severity of their hypertension. AMP-activated protein kinase (AMPK) is responsive during metabolic stressors, plays a vasoprotective role in endothelial function, and is stimulated during exercise training. Studies have suggested that signaling pathways activated by AMPK may play a protective role in hypertensive models given AMPK’s involvement in redox balancing. The purpose of this study is to determine the therapeutic potential of AICAR (5-aminoimidazole-4-carboxamide-3-ribonucleoside), a potent AMPK stimulator, for ameliorating hypertension. Uninephrectomized Sprague Dawley rats received DOCA-salt treatment and daily administration of either AICAR (100mg/kg/day) or vehicle (20%DMSO + 0.9% saline) subcutaneously for 21 days. Cardiovascular and renal function were assessed by radiotelemetry, tail cuff, and GFR. MAP reached 183.6 ± 26.16 and 179.4 ±26.49mmHg in AICAR and vehicle treated groups respectively. No differences were observed in cardiovascular function between the two hypertensive groups. Notably, no change in renal injury or function was detected in either treatment as shown by the final GFR (0.841±0.4813 vehicle, 0.7578±0.2937 mL/min/100g b.w AICAR). From these findings we concluded that exogenous administration of AICAR does not attenuate hypertension in the DOCA-salt model
Topographical Tests of Landscape Evolution Schemes, Central Australian Ranges
No full textPrevious studies have documented the unusually long evolutionary histories of the central Australian mountain ranges (e.g., MacDonnell, Krichauff, Waterhouse, and James), including early planation (late Mesozoic); subsequent deep weathering and associated etchplanation under humid/tropical conditions; cross-axial river incision; long-term stream impression; and progressive aridity; all associated with regressive river erosion, stream capture, and epeirogenetic tectonism. The present investigation employs newly available topographic data to advance understanding of these phenomena, to test previously proposed explanations for some of them, and to discover some new geomorphological puzzles in this very interesting region. Important discoveries made by this study include (1) confirmation of the very ancient landscape elements, as demonstrated by the Tnorala impact structure (145 Ma), (2) deformations in both cross-axial and ridge-and-vale landscape profiles that reveal possible epeirogenetic influences on the topography, (3) remarkable adjustment of major river longitudinal profiles across diverse geological structures, (4) special consequences of etchplantion for the drainage evolution of “intramontane basins,” (5) the phenomenon of incised bedrock paleomeander palimpsests for both the Larapinta (Finke) and Hugh Rivers, and (6) the phenomenon of “in-and-out” gorges
Effects of Small Molecules Mimicking cTnI Phosphorylation on the Hypertrophic Cardiomyopathy-Causing R92L-cTnT Mutation
No full textThe cardiac sarcomere is the contractile unit of the heart. It is composed of regulatory filaments: thick filament, thin filament and titin. Titin acts as a molecular spring, keeping the thick filament centered in the sarcomere. The thick filament is primarily composed of myosin, which acts as the motor protein for sarcomere contraction. The thin filament (TF) is composed of the proteins actin, tropomyosin (TPM), and the troponin (Tn) complex (consisting of troponin C, T, and I). The thin filament is responsible for the regulation of calcium-sensitive contraction. Ca2+ binding to cTnC results in conformational changes in the TF that allow for actomyosin cross-bridges, generating force during contraction. Mutations in sarcomeric proteins have been linked to genetic cardiomyopathy forms such as hypertrophic cardiomyopathy (HCM). Impaired left ventricular relaxation and dysregulated Ca2+ homeostasis are common in HCM, often contributing to diastolic dysfunction. The Arg92Leu (R92L) mutation is a missense substitution in the gene TNNT2, that encodes for cTnT. This mutation is an HCM-causing mutation resulting in left ventricular hypertrophy and impaired diastolic function due to allosterically mediated changes to protein flexibility and cTnT binding properties to tropomyosin. Protein kinase A (PKA) mediated phosphorylation of cTnI-S23S24 has been shown to be important to early sarcomeric relaxation, and the phosphorylation potential of cTnI is reduced in the R92L-cTnT mutation. The R92L-cTnT mutation also has decreased rates of calcium dissociation from cTnI compared to wildtype. Mimicking cTnI phosphorylation increases the rate of calcium dissociation in both wildtype and R92L-cTnT reconstituted protein and mouse models. A sequence of screens was designed to identify small molecules that result in time-resolved fluorescence structural changes, as well as changes in the stopped-flow calcium dissociation kinetics. The stopped-flow calcium dissociation kinetics screen was conducted on a fully reconstituted cardiac thin filament, using bacterially-expressed protein based on the human sequences. The Selleck and ACDD Diversity drug libraries underwent structural and stopped-flow Ca2+ dissociation kinetics screening, and compounds that increased the percent change of stopped-flow Ca2+ dissociation kinetics were selected as candidates to undergo further screening. We hypothesize that the effect on the percent change in Ca2+ dissociation rates due to individual small molecules will translate from in vitro to ex vivo studies. NADH-coupled myofibril ATPase was used to assess the effects of the small molecules on the R92L-cTnT myofibrils, which have increased actomyosin interactions at baseline. The two small molecule candidates with the most significant decreases in ATPase rate were then tested on isolated R92L-cTnT cardiomyocytes for analysis on a more complex ex vivo system level. Data collected on isolated myofibrils and cardiomyocytes will provide information regarding how the small molecules affect the impaired function caused by the R92L-cTnT mutation, with the possibility of identifying candidates to proceed to in vivo studies on mouse models. Results of these studies will provide information about the validity of the primary structural and the secondary calcium dissociation kinetics screens as a method identify small molecules that bind to the thin filament and modulate ATPase activity
Use of a Thematic Template in L2 Korean Relative Clause Comprehension
No full textThis study aims to capture a comprehensive picture of the heuristics internalized and exhibited by L2 Korean learners, across case-marked and non-case-marked environments. It further examines how perceptual processes—such as segmentation and grouping—underlie these heuristics and seeks empirical evidence for the cognitive costs associated with the functional relabeling of structurally specified NVNV strings. This dissertation comprises three studies investigating the formation and use of NVN and NVNV templates in the comprehension of Korean relative clauses by L2 learners. Together, these studies offer insights into the heuristics employed by L2 users when processing Korean relative clauses. The functional labeling of bare NVN strings by English-speaking learners was not initiated based on the heuristics rooted in the canonical order of their L1 English (i.e., NVN as SVO). Instead, they directly adopted the way of labeling the word sequence of the target structure (i.e., [RC NV]N as [OV]S), similar to how native Korean speakers do. However, L2 users made errors primarily due to the difference in head-directionality between L1 English and L2 Korean, resulting in structurally constrained internal relations in Korean. In typical RC sentences, case markers are employed, requiring the parser to accommodate case-informed NVNV sequences during processing. Consequently, the perceptually internalized template of bare NVNVs (i.e., a mental model) is guided to adjust to one of the four possible variations of RC NVNV strings that include nominative and accusative markers. I argue that this adjustment process enables appropriate interpretations and can be understood as a functional relabeling phenomenon in L2 Korean learning
From Investigation to Endoscope: Optical Biomarkers for Cancer Diagnostics
No full textIn this dissertation, we conducted a multimodal imaging study on fresh human esophageal tissue samples obtained via endoscopic biopsies from 26 patients. Four distinct imaging modalities were performed: autofluorescence imaging, hyperspectral imaging, optical coherence tomography, and Mueller matrix polarimetry. The primary objectives were to address three key research questions: 1) Which individual modality best differentiates between healthy and cancerous tissue? 2) How can data from these modalities be integrated to maximize discrimination? and 3) What computational methods are suitable for analyzing the resulting high-dimensional multi-modal datasets? Our findings indicated polarized light imaging provided the highest discriminatory capability among the imaging modalities, yet when looking at flexible endoscopic translation we found a technology gap existed in polarimetry and flexible endoscopy. The next section of the dissertation focused on proposing and demonstrating a simple, compact, and low-cost architecture to enable snapshot spatial polarization measurements through a flexible imaging fiber. Specifically, we introduced a snapshot spatial polarization imaging approach using a pixelated polarizer integrated at the distal tip of a coherent imaging fiber bundle. The proposed optical architecture, combined with a robust computational workflow, represents a significant advancement towards addressing current technological challenges in flexible endoscopic polarimetry