Master's Theses
ABOUT THE COLLECTION
The UA Master's Theses Collection provides open access to masters theses and reports produced at the University of Arizona, including theses submitted online from 2005-present and theses from 1895-2005 that were digitized from microfilm and print holdings, in addition to master's reports from the College of Architecture, Planning and Landscape Architecture from 1966 onwards. The collection includes hundreds of titles not available in ProQuest.
We have digitized the entire backfile of master's theses and doctoral dissertations that have been submitted to the University of Arizona Libraries - since 1895! If you can't find the item you want in the repository and would like to check its digitization status, please contact us.
The UA Master's Theses collection is not comprehensive; master's theses from 1993-2015 were only received and archived by the UA Library and ProQuest if the student chose to pay the optional archiving fee. The Library does not have copies of many master's theses submitted during this time period. Some academic departments may keep copies of theses submitted to their programs. Colleges and departments wishing to archive master's theses not available in the University Libraries are encouraged to contact us at repository@u.library.arizona.edu.
QUESTIONS?
Please refer to the Dissertations and Theses in the UA Libraries guide for more details about UA Theses and Dissertations, and to find materials that are not available online. Email repository@u.library.arizona.edu with your questions about UA Theses and Dissertations.
Recent Submissions
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Evaluating Commercial Cervical Immobilization Devices for Prehospital Use: Identifying the Most Comfortable Model for AdultsCervical Immobilization Devices (CIDs) are a routinely used intervention in the prehospital and in hospital care of patients with suspected cervical spinal injury. However, there is limited evidence regarding the comfort of CIDs, especially given the increasing number of commercially available immobilization devices on the market. This study aimed to address the current literature gap by evaluating comfort levels, pain and perceived movement restriction in various commercially available CIDs. Descriptive and statistical analysis were used to compare the results, and linear regression was performed to examine the effects of various covariates. A convenience sample of fifty subjects (18 Female, and 32 Male) were recruited. Mean age 35.9 years old (SD) 1.85 years. Results showed that the relative risk (RR) of a participant an abnormal positioning while wearing a collar was lowest with Collar C (SipQuik Cervical Collar, Soft Collar) (RR 0.25, 95% CI 0.09 - 0.70) (Table 2 & Figure 3). Although the remaining collars (A, D, and E) also had lower RR values, these were not statistically significant. The RR of experiencing pain or tenderness after three minutes collar application, was similar across all models (Table 2 & Figure 4). None of the results reached statistical significance, indicating that no collar was definitively superior in reducing discomfort. Results also showed that the more rigid collar types (A and B) showed the highest number of participants (n=14 and n=12) respectively reporting an inability to move their head in any direction. On the other side, Collar C had the highest number of participants stating that they could fully move their head in any direction. There were no statistically significant effects from the covariates, except for one instance, Collar D, where a positive correlation was found between weight and movement restriction (p < 0.05). While the current study gives valuable insights on the preferred model cervical collar when healthy adults are the sole participants, more research into subjective experiences while wearing cervical collars is still needed. The study findings show that the chosen collar type may be more dependent on specific aspects such as correct application and immobilization capabilities than on the participants physical attributes such as weight, height, and age. With the ongoing controversy, further research on collar comfort preference is still required. This study highlights variations in comfort and movement restriction among different commercially available cervical collars. While many studies have examined the biomechanical effectiveness of cervical collars, limited research has focused on their impact on patient comfort, a crucial factor influencing compliance and tolerance in both prehospital and in-hospital settings. This study contributes to the broader conversation about best practices in prehospital trauma care. If certain collars are found to cause significant discomfort without offering superior stabilization benefits, reconsideration of current immobilization protocols may be warranted. Ultimately, this research supports a more evidence-based approach to cervical spine immobilization, prioritizing both patient safety and experience in trauma management.
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Discursive Constructions Of Homosexuality In Kenya: A Corpus-Driven Discourse Analysis Of The German Press(Recent) legislations surrounding LGBTQ+ discourses in Kenya and beyond have invited visibility and coverage from both local and international media outlets. Building on studies that examine LGBTQ+ social justice and human rights, this study analyzes how German Newspapers in particular frame news surrounding homosexuality in Kenya. In this study, I use LexisNexis, a corpus data source to source newspapers that thematize Homosexualität in Kenia between 2014 to 2024 and then I apply Critical Discourse Analysis (CDA) by Van Dijk, to interpret and analyze the results through a macrostructural perspective. The study quantitatively employs a corpus-based analysis, in which Sketch engine, a corpus linguistic tool is used to determine concordances, collocations, and keyword analysis. The study borrows from qualitative theories in which the concepts of Representation by Stuart Hall and the Frankfurt school theory by Theodore Adorno are applied. The results highlight the dominance and intersection of discourses such as the prevalence of homophobia, Western influence, the discursive positioning of Uganda and South Africa, and the reporting of a collective Africa. The study is relevant in unraveling the discursive strategies that inform and shape how the state of homosexuality in Kenya is reported about from a German newspaper perspective. It is necessary to examine German media perspectives of homosexuality in Kenya to gain a more nuanced and historical understanding of how these discursive patterns of German witnessing about Africa get made/remade in media contexts.
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Scaling Data Driven Building Energy Modeling using Large Language Models: Prompt Engineering and Agentic WorkflowData-driven building energy modeling (BEM) faces scalability challenges due to the complexity of diverse building and data types as well as integrating them into effective models. Large language models (LLMs) offer significant potential to enhance code generation and reasoning capabilities, which could facilitate broader adoption and implementation of data-driven BEM. In this paper, I hypothesize that LLMs can incorporate domain-specific knowledge into data processing and modeling, enabling automation of data-driven BEM across building types (residential and commercial), modeling output (zone temperature and energy consumption), and specific modeling needs. This paper leverages LLMs in the forms of prompt engineering and agentic workflow. A Machine Learning Operations (MLOps)-based prompt template is developed to systematically generate Python code for data-driven modeling. Experiments are carried out around four BEM scenarios and results indicate that both approaches are effectively scalable for implementing data-driven BMS solutions where bi-sequential prompting achieves the highest success rates of 95% in code accuracy. The agentic workflow, a paradigm where agents utilize planning, action, tools, and memory, further improves the automation, self-correction, and interaction with LLM, and resulting in improved accuracy to 100%.This framework can help energy engineers, facility managers, and sustainability consultants in automating BEM workflows, especially where coding expertise is limited, or scalability is a priority.
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Women in Greek and Roman AthleticsThis thesis addresses scholarly debate about whether women participated in athletics in the ancient Greek and Roman worlds. Some people still argue today that women could not participate in ancient athletics, using restrictive definitions of what is considered as athletic and sometimes omitting important evidence. The assumption that women did not participate in ancient athletics was also the basis of Victorian era arguments against women’s inclusion in sports. Pierre de Coubertin, for example, vehemently opposed women’s inclusion in the modern Olympics, citing “ancient ideals” as a reason not to allow women in sports. This work provides a great deal of evidence that women did participate in ancient athletics, assessing both literary and material evidence from the ancient world. There is a particular emphasis on material evidence to provide a sense of what female athletics were like in the ancient world without the biases of ancient authors. Ancient literature especially demonstrates how women’s participation in athletics was received at the time. This work also draws connections to the modern era, outlining how participation in women’s sports has increased since the Victorian era and arguing against the misuse of ancient evidence in the modern world to bolster claims that women should not participate in sports.
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Orpheus, Pre-Socratics, Exegesis, and the Near East: A Cross-Cultural Analysis of the Derveni PapyrusThis thesis is a holistic analysis of the Derveni papyrus and a survey of the many influences on the text from across the broader Mediterranean world. Each chapter of the thesis separates the Derveni papyrus into a discrete, generic category, and draws fruitful parallels with Greek and non-Greek texts to highlight the seemingly disparate sections of the Derveni papyrus. In chapter 1, I analyze the Derveni papyrus as a piece of Orphic literature. I first highlight the aspects of the text that are considered Orphic and clarify methodological points about the classification of texts as Orphic. I then compare the Derveni papyrus to attestations of other surviving Orphic texts, such as the Eudemian Theogony, the Hieronyman Theogony, and the Rhapsodies. I also analyze the connection between these Orphic theogonies more broadly, and Hesiod’s Theogony. I then turn my attention to the broader Mediterranean to evaluate potential comparisons with texts from the non-Greek world, such as The Kumarbi Cycle of the Hittites, the Babylonian poem Enûma Eliš, the Vedas of India, Zoroastrian cosmologies, and Phoenician cosmologies. Finally, I consider the archaeological context of the papyrus, comparing the context to that of the Thurii Tablets. In chapter 2, I evaluate the influences of Pre-Socratic philosophers on the Derveni text, such as Heraclitus, Anaxagoras, Parmenides, Empedocles, and Democritus, followed by an analysis of non-Greek philosophy, in the form of the magoi from the Achaemenid Persian Empire. In chapter 3, I evaluate the Derveni papyrus as a commentary, starting with an overview of ancient commentaries, such as the Alexandrian commentaries, and the tradition of allegorical exegesis. I then turn to non-Greek traditions of commentaries, such as the tradition of Babylonian commentary on the Enûma Eliš, and the Qumran pesharim. Finally, I conclude that this method of comparison is intellectually valuable for discerning basic facts about the Derveni papyrus, such as its date of composition, and for certain facts about the intellectual background of the Derveni author.
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Dose-Dependent Temporal Dynamics of FOXO1 and 53BP1 in Response to H2O2-induced Oxidative StressOxidative stress driven by reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), plays a pivotal role in regulating cellular homeostasis and genomic stability through activation of stress response pathways, including DNA repair mechanisms. This study investigates the temporal dynamics of Forkhead box-O1 (FOXO1), a key transcription factor for maintaining cellular homeostasis and p53-binding protein-1 (53BP1), a crucial player in the DNA damage response, in response to varying doses of. H2O2-induced oxidative stress. Cells harboring FOXO1 and 53BP1 fluorescent reporters were exposed to increasing concentrations of H2O2 and FOXO1 activation and 53BP1 foci formation were tracked using live cell microscopy over a 24-hour period. Quantitative image analysis revealed that FOXO1 nuclear localization exhibited a rapid but variable activation pattern across cells, with duration increasing in a dose-dependent manner. In contrast, 53BP1 foci formation showed a surprising slower accumulation at higher H2O2 concentrations, suggesting possible impairment of double-strand break (DSB) DNA repair or a shift towards alternative repair pathways. Our findings indicate that oxidative stress modulates DNA repair dynamics in a dose-dependent manner, with higher levels of H2O2 potentially altering the efficiency or pathway choice of DSB repair mechanisms.
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Unraveling the Relationship Between Central, Peripheral and Cerebral Arteries Function in a Mouse Model of Marfan Syndrome: Benefits of Exercise Training on Vascular Function and Blood FlowMarfan syndrome (MFS) is a connective tissue disorder caused by mutations in the fibrillin-1 gene affecting the musculoskeletal, cardiovascular, and pulmonary systems, with a notable vascular effect leading to aortic aneurysm, dissection, and rupture. In recent decades, better diagnostics and advances in medical and surgical treatments have increased the life expectancy in individuals with MFS, hence, other vascular complications have become more concerning. Aging is the dominant risk factor for clinically significant atherosclerotic lesions affecting most often the carotid arteries and carotid artery tortuosity is highly associated with connective tissue diseases, particularly MFS. There is an increased prevalence of intracranial aneurysms and ischemic stroke in hospitalized patients with MFS when compared with healthy controls. Despite these reports our understanding of cerebrovascular and carotid artery function and structure in MFS is very limited. In addition, the cardiovascular benefits of moderate exercise training have been well documented in the literature. Numerous studies have shown that aerobic exercise can improve cognitive function, decrease neuropsychiatric and neurodegenerative symptoms. This study sought to explore the impact of mild aerobic exercise on the progression of vascular complications in both male and female MFS mice, utilizing high-resolution in vivo ultrasound imaging for precise analysis. The research focused on assessing the functional properties of multiple key arteries, including the aorta, posterior cerebral, carotid, coronary, pulmonary, and renal arteries, in both male and female MFS mice. The study also aimed to explore the relationship between MFS-associated structural and functional changes in the aortic root and phenotypic alterations in other arteries, with the objective of identifying key predictors that could provide insights into vascular health and the potential impact of exercise on arterial structure and function. At 6 weeks of age, male and female control (Fbn1+/+) and MFS (Fbn1C1041G/+) were divided into three experimental groups: Ctrl, MFS, MFS + exercise. MFS mice were subjected to an exercise regimen of 8m/min, 30min/day, 5days/week. At 7 months of age, in vivo ultrasound imaging was performed to measure aortic root diameters and pulse wave velocity, the carotid artery pulse wave velocity (PWV), wall thickness and distensibility, and the peak systolic velocity (PSV) of the posterior cerebral arteries, coronary, pulmonary, and renal arteries. Our data showed significant increases in aortic root diameter and pulse wave velocity (PWV), carotid wall thickness and arterial stiffness, along with reduced carotid distensibility, in both sexes in MFS mice compared to controls. Peak systolic velocity (PSV) was significantly reduced in the pulmonary and posterior cerebral arteries of MFS mice, with no changes observed in coronary or renal arteries. Mild exercise mitigated aortic and carotid pathology by reducing aortic root diameter, PWV, and carotid wall thickness, while restoring carotid distensibility and posterior cerebral artery blood flow, especially in female MFS mice. Sex-specific analyses showed that aortic PWV was a strong predictor of posterior cerebral artery blood flow and pulmonary artery flow in males, whereas sinus of Valsalva diameter strongly predicted carotid artery PWV and wall thickness in both sexes. However, the relationships involving arterial distensibility differed between males and females. These findings highlighted the vascular impact of MFS, the therapeutic potential of exercise, and significant sex-specific differences in disease progression and associated metrics.
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Writing the Identity of the Homeland: Indigeneity and National Identity in Salvadoran LiteratureBefore the 1990s, El Salvador’s national identity had long been characterized as completely miscegenated through the claimed disappearance of all indigenous people by the state. Strongly reinforced through an ethnocide in 1932, the myth of complete mestizaje in El Salvador was cemented in the Salvadoran imaginary and beyond, aligning with Eurocentrism and neoliberal policies that structured dominant concepts of nation-building in Latin America at the time (DeLugan 2012). After the end of El Salvador’s civil war, the emergence of a regional transnational indigenous movement (Tilley 2002) marked a new period of nation-state and collective identity construction where the Salvadoran state no longer outright denies the existence of indigenous peoples in El Salvador, but continues to have inconsistent approaches, attitudes, and formal narratives regarding indigeneity and indigenous history. With formal and informal sites of cultural knowledge transforming under international networks and standards, sites of cultural production like national literature provide a point of reflection for the Salvadoran imaginary’s construction of, and relationship to, indigenous and nation-state identities. Through the poems of the Salvadoran anthology Tzuntekwani, I analyze the rhetoric of contemporary national literature that constructs indigenous identity around specific sites of state violence, certain Mesoamerican and local cultural markers, geographic location and environment, and socioeconomic marginalization. This thesis aims to understand the relationship between collective conceptualizations of national identity, or identities, in El Salvador’s formal state rhetoric and national literature in the 20th and 21st century.
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Modeling Growth of Chlorella Sorokiniana by Changing CO2 Nutrient Concentration and pH Dynamics by Convective Mass TransferChanging pH in a system will have effects on almost all aspects of biological life in that system. Understanding how the pH changes in a system through the addition of CO2 over time is important to determine how life in that system will react. Additionally, algae has been well-researched due to its potential in biofuel production and water treatment. Understanding the role of carbon dioxide availability on the growth of algae is important to produce enough algae for these uses. This study explores both the modeling of dynamic pH effects through use of the convective mass transfer coefficient and the growth effects of CO2 on Chlorella sorokiniana. All algal growth experiments were conducted at a temperature of around 35º C, a light intensity of 234 µmol m-2 s-1, and a 12-hour light phase in a 24-hour cycle. Experiments were conducted with feed CO2 compositions between the concentration in air and 5%. A one parameter model was applied to data to find the growth rate. The trials showed that an excess composition of CO2 does not have a significant impact on the growth rate while CO2 limited trials give a decreased growth rate. The dynamic pH trials in different media were fit to a one parameter model. These pH experiments showed that the pH could be accurately modeled through the equations in this study and that the convective mass transfer coefficients for the absorption and desorption processes of CO2 were likely different.
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La Migración Humaniza: Experiences of Enacting Migrant Care in GuatemalaFrom Arizona’s borderlands to Guatemala’s highlands, spaces that offer hospitality to migrants play a crucial role in the journey of the growing number of people whose lives are in transit. This research follows the experiences inside Casa Myrna Mack during its first months of operation, highlighting the overall work of la Red Jesuita con Migrantes Guatemala from the perspective of staff and volunteers to understand the work, impact, and embodied experience of offering hospitality to migrants in Guatemala. This research contributes to bodies of knowledge surrounding the migrant experience, specifically emphasizing spaces of care, and provides a nuanced and ethnographic perspective of humanitarian action beyond macropolitical and institutional approaches common to existing discourse. Key themes explored in this project include the motivations driving humanitarian actors, the emotional and physical impact of enacting migrant aid on staff and volunteers, and the potential for this work to have politicizing effects as collaborators navigate the complexities of providing care within an uncaring political context, a question with resonance well beyond Guatemala.
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Diffusion Connectome Analysis in a Rat Model of HypertensionWhile hypertension is recognized as a significant risk factor for cerebrovascular diseases(e.g., Alzheimer’s Disease and dementia) and cognitive decline, its impact on brain connectivity is not fully understood. A prior study investigated the effects of induced hypertension on the macrostructural and microstructural anatomy of Fischer 344 Cyp1a1-Ren2 transgenic rats using diffusion MRI (dMRI). Results showed that while hypertension resulted in end-organ damage in the heart and the kidney, the brain remained unaffected in terms of volume and microstructural characteristics. The purpose of this study is to further investigate the effects of hypertension on structural white matter connectivity in the same transgenic rat model using connectome analysis. Connectomes were generated from diffusion data collected and processed in the previous study using probabilistic tractography. Structural connectivity was quantified and compared between and within normotensive and hypertensive rats at baseline and 10 weeks across four regions of interest (left cortex, right cortex, left hippocampal CA subfields, and right hippocampal CA subfields). No significant differences were observed in structural connectivity across these four regions, further establishing the findings reported in the prior study. These findings indicate that the brain may implement intrinsic protective mechanisms to preserve structural connectivity and mitigate damage from hypertension, even in the presence of systemic end-organ damage.
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Archaeomusicology and Cross-Cultural Comparisons of Reed Instruments in Greco-Roman Antiquity: From the Aulos to the BagpipesThe aulos was a notable reed instrument in ancient Greek and Roman music, one significant but poorly documented variation of which was the bagpipe from the late Hellenistic period; this thesis will focus on the enigmatic bagpipe and its relationship to the aulos. The bagpipe was first developed in ancient Greece around the 1st c. BCE. Although no archaeological examples of this instrument survive, iconographic and literary records affirm its presence. Analysis can also be aided by its close relative, the aulos – the ancient double pipe. This thesis employs archaeomusicology – the study of music through archaeological methods – and aims to identify the form and materials of the ancient bagpipe through analysis of archaeological artifacts, iconography, literature, and living tradition. This cross-cultural comparison has shown that the ancient bagpipe likely used goat skin for the bag and wood, bone, or reed for the pipes. Additionally, evidence suggests that the ancient bagpipe may have used a single-reed instead of a double-reed for its intonation. This study serves the larger scholarship by furthering the knowledge of ancient Greek music culture, particularly in non-elite contexts, and laying the groundwork for potential future research and experimental projects on the musical characteristics of the ancient bagpipe.
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Segmenting Fluorescent-Dyed Cell Images Using Mask R-CNNThis project explores the impact of contrast-related hyperparameters on cell detection performance in fluorescent-labeled images. We focused on optimizing model architectures and training strategies, with an emphasis on static and dynamic auto-contrast methods. Our findings show that SGD with momentum consistently outperformed other optimizers across dynamic auto-contrast configurations. Static auto-contrast methods, particularly those using Pillow and PyTorch, enhanced edge detection, but occasionally hindered the visibility of fluorescent Kog1 bodies crucial for classification. Kernel size variations in the Basic Convolutional Block module did not significantly affect performance. Data augmentation proved effective in improving model generalization on a small dataset. Among the dynamic auto-contrast models, the Baseline Mask R-CNN model provided the best performance. In support of our hypothesis, static auto-contrast methods improved segmentation accuracy by enhancing edge definition and feature visibility. Our best-performing model achieved segmentation accuracy within 5% of ACCT, a state-of-the-art model for brightfield images, demonstrating the value of contrast-aware preprocessing in fluorescent image segmentation.
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Surface Roughness Arising from Ultrafast Laser Techniques Performed on Glass for Fabricating X-Ray OpticsX-ray astronomy uses grazing incidence optics that require sub-nanometer surface roughness and nanometer-level surface figure accuracy before and after fabrication. To maintain these precise surface characteristics, flexures can be incorporated into the mirror geometry, allowing controlled deformation of the reflecting region. Achieving the complex geometry of flexures on glass substrates is done with ultrafast laser assisted chemical etching. This thesis tests how chemical etching affects the surface roughness of glass mirror substrates (fused silica and Corning ULE) in hopes that chemical etching does not degrade the surface further than the initial surface roughness. It was determined that chemical etching did not significantly degrade the surface roughness of the glass substrate. The structure of an x-ray telescope system requires high reflectance on the mirror side, while having low reflectance on the back surface. To measure the mirror surface through the back surface, an anti-reflection (AR) coating can be helpful to provide low reflectance on the back surface. Laser-induced modifications on the surface of a transparent substrate, dubbed nanopillars, are a potential solution to create a long-term stable AR coating. Due to nanopillars on the substrate surface being hundreds of nanometers tall, they could be a viable solution to provide low reflectance for the x-ray band and visible light. This thesis evaluates the formation of nanopillars on fused silica and ULE glass to find optimal parameters for creating an AR coating. Using low pulse energy and multiple passes over the same laser-modified area achieved the desired nanopillar structures about 300 nm tall.
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Opto-Mechanical Design and Stray Light Analysis for Unobscured off-Axis Telescope using BRDF Data of Black PaintsSpace telescopes are an extension of the human eye into distant galaxies that allow forthe observation and imaging of phenomena light years away from Earth. There are many variants of space telescopes; a widely cherished design is the three mirror anastigmat (TMA). The TMA is coveted because of its ability to correct for aberrations over a wide field of view. A variation of a typical TMA is an off-axis system that removes the central obscuration of the telescope’s primary mirror (M1). However, the benefits of an off-axis TMA come at the cost of complex mechanical housing of the optical components and stray light correction. Professor Daewook Kim has optically designed an off-axis TMA. This thesis will give an overview of the optical design of the TMA, give an in-depth description of the mechanical design of the baffles, vanes, and apertures of the telescope, describe the collection process of real scatter data of black paints applied to the housing, and outline the stray light analysis performed on this system. The TMA is an f/14 system with a clear aperture of 3000 mm that is essentially diffraction limited. The system has an approximated FOV of +/-0.27◦ by +/-.08◦ and is designed for a semicircle detector plane. In addition to the three curved mirrors, there is also a fourth, folding mirror at the end of the system before the detector. Baffles, vanes, apertures were designed for stray light control of the TMA system. The design was constrained to be less than 9 m by 5 m, and as compact as possible. Real BRDF data was collected and processed for stray light analysis. Different black paints have varied scattering characteristics. Thus, it is essential to measure and apply real BRDF data of various black paints to the mechanical system to ensure accurate stray light analysis. Stray light analysis was performed with the target of less than 10−5 of light was incident on the detector relative to the in-science field for far out-of-science fields.
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Association Mapping of Rice Flag Leaf Primary Metabolism Uncovers Major Multitrait Qtls Related to Yield Performance Under DroughtRice (Oryza sativa) is the primary food for over one-third of the global population, yet its productivity is increasingly threatened by drought. To better understand the metabolic basis of drought tolerance and grain yield, we performed a metabolic profiling on a panel of 271 indica rice accessions grown under well-watered (WW) and water-deficit (WD) field conditions. The WW field remained flooded, while the WD field experienced 14 days without irrigation at 50% flowering, followed by re-watering until maturity. Flag leaf samples were analyzed using untargeted gas chromatography-mass spectrometry (GC-MS) metabolomics and a total of 89 primary metabolites were annotated and quantified. The rice accessions were genotyped via genotype-by-sequencing (GBS), generating a 47K SNP map available for genome-wide association studies (GWAS). We identified 184 QTLs associated with the variation in the metabolite values: 114 under WD, 70 under WW, and 19 shared across conditions. Four high-density regions (HDRs), each harboring ≥4 metabolite QTLs, were found on chromosomes 1, 4, and 11. Principal component 1 (PC1) of each HDR-associated metabolites correlated strongly with grain yield. Fine mapping using a 1.5 million SNP map revealed 35 candidate genes within HDRs, including promising targets such as IAAS (Os01t0785400), NSP1 (Os01t0784900), proteases (Os04t0477900, Os04t0479800), and CYPs (Os04t0480650, Os04t0480700). These genes and HDRs represent valuable candidates for breeding drought-resilient, high-yielding rice varieties.
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Baptizing the Bees: Vergilian Allegory in Confessions 9.10This thesis examines how Augustine forms intertextual links between Vergil’s Georgics 4 and his Confessions 9.10. Both texts employ themes of katabasis, sacrifice, rebirth, perfect society, and didactic heroism, which enables Augustine to intertextually lift Vergil’s text out of its original context and into a new Christianizing and Neoplatonic context. To understand how Augustine forms this intertext, I begin the thesis by developing a theory of intertextuality which compares the process of intertextuality to allegorical interpretation. I next consider the role Augustine gives to Vergil’s Georgics 4 in Confessions 10, where Augustine prominently makes allusion to the Vergilian text. Although textual allusion to Vergil is not a prominent feature in Confessions 9.10, I argue that the scene in Confessions 9.10 is structurally and thematically similar to Augustine’s treatment in Confessions 10. The thesis concludes by considering how Confessions 9.10 plays on the themes found in Georgics 4, and how Augustine is able to assert his own perspective onto Vergil’s text by placing it into a Christian context.
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The Ages to Come Are WisestIn this paper, I examine the proposition supplied by the earliest historians: that their subject, the events of the past, is worthy of record and study. Rather than approaching this premise from a theoretical standpoint, I will instead project that question onto the problems faced not by a collective group, but by a single individual, whose example is drawn from the series of novels (affectionately known as the Soldier novels) by the American science–fiction/fantasy author Gene Wolfe. I suggest that a different way of thinking about historiography may be reached by considering the problems common to historiography and to the protagonist of the novels, whose situation is uniquely fitted to such an exercise. I then demonstrate how this may be done through a comparison of situations occurring in the fictional world of the Soldier novels with those recorded by ancient writers. This comparison does not necessarily aim to confirm or deny the idea that a study of historiography can provide benefit to present actors, but rather that considering these events in comparison with Latro’s story provides new insights into their importance.
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Evaluation and Correction of Narcissus in Infrared Systems with Cooled Focal Plane ArraysInfrared imaging systems with cooled focal plane arrays can achieve high thermal sensitivity performance. However, cooled infrared cameras are susceptible to additional stray light artifacts such as narcissus. Narcissus arises from the internal reflection of thermal radiation from a cooled detector and warm surrounding structures off refractive optical surfaces with imperfect anti-reflective coatings. Narcissus results in a spatially varying radiometric artifact, often manifesting as a cold spot across the focal plane array, which can severely degrade image uniformity and thermal sensitivity. This thesis presents an investigation into the manifestation of narcissus and how it can be simulated using ray tracing to quantify its impact on an infrared system. A discussion of different design strategies for correcting narcissus is also covered. The physical basis of narcissus is examined through paraxial optical analysis, employing Lagrange invariants to characterize the relationship between lens surface geometry and the formation of narcissus artifacts. A key outcome of this analysis is the derivation of the Narcissus Induced Temperature Difference (NITD), a quantitative figure of merit that represents the apparent temperature shift observed by the detector from the narcissus artifact. The NITD figure of merit enables the evaluation of narcissus across the image plane and guides the lens designer toward possible corrective actions. To reinforce the theoretical analysis, a case study is conducted on a MWIR camera system. Reverse raytracing simulations model the thermal self-emission background across the focal plane and determine surface-level contributions to NITD. The simulation workflow enables the generation of spatially resolved thermal irradiance and NITD maps, which inform the distribution and magnitude of narcissus across the focal plane. Various mitigation strategies are then explored, including optical system cooling, optimization of lens curvature and spacing, improvements to anti-reflective coatings, and tilting plano optical elements to redirect reflected thermal radiation away from the detector. This thesis demonstrates that integrating NITD analysis into a design workflow while employing different corrective measures can significantly reduce narcissus to enhance image quality and thermal sensitivity performance. The results highlight the importance of incorporating narcissus modeling and optimization early in the design cycle to ensure system performance requirements are met without high cost and scheduling risk if discovered later in the project timeline. The methods developed in this work provide a structured and practical approach for addressing narcissus in cooled infrared systems and can be readily integrated into existing optical design and analysis workflows.
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Complex Spatial Decision-Making: Investigations Into Explore-Exploit Behaviors and CA1 Multi-Field Cell Activation in MegaspaceExplore-exploit behavior is a decision-making process involving the exploration of new options without the certainty of consequence or the exploitation of familiar options known to have a predictable outcome. This behavior is critical for organisms to survive and thrive when navigating the real world, but how is such a balance achieved between these decision-making tendencies? What characteristics can be measured/controlled to quantify them? We address these questions using the same changing bandit task in rats and humans. In the changing bandit task, a subject is asked to choose two options with a priori unknown rewards/outcomes. Based on the session type, each option possesses a constant, unknown hazard rate which determines the probability at which the reward amount changes at each option, modulating the volatility/reliability across each trial. We hypothesize that both rats and humans will learn to switch options (explore) after the lowest reward amount is dispensed especially if the hazard rate is high, and will persist if the option yields the highest reward especially if the hazard rate is low. The rats are placed in a maze where they must first go to an unrewarded “home base” before two feeders opposite the home base start blinking. Rats probabilistically receive either zero, one, or three drops of a sucrose solution as rewards. Preliminary results show that both male and female rats are more likely to exploit the highest rewarding feeder than the reliable but less rewarding feeder and seem to display more exploitative behaviors with time. A MATLAB-based GUI was created and used for the human subjects to mimic the changing bandit task using a point-based reward system. Human subjects experience the exact same series of decisions as the rats. Decisions, reaction times and computer mouse tracking data are collected. Initial results from seven participants indicate that humans and rats are qualitatively comparable. Additionally, compared to rats, while humans are more likely to exploit the highest rewards in any case, rats will do so more consistently under certain volatility parameters. More human participants, rat trials, and analysis are required to draw more conclusions about the similarities/differences between the two species.Within the hippocampus, place cells exhibit location-specific firing. Regions of place cells with high firing activity are referred to as place fields. Dorsal place cells have been previously explored in rats in small environments. In small mazes, dorsal place cells form one and rarely two place fields. Recently, place field activity has been studied in megaspace, a large environment about eight to nine times larger than traditional mazes. Dorsal place cells in this larger space commonly feature multiple place fields of varying sizes (one to eight subfields). Why does a single output cell in CA1 fire at different locations in megaspace? We hypothesize that CA1 subfields are ‘bound’ to each other by neural activity in the presynaptic CA3. The binding between subfields can be evidenced by partial synchrony of cells in each field. Thus, to test this hypothesis, we used the NEURON biophysical simulator to create three ‘bound’ CA1 place fields and alter the connectivity matrix to simulate differing conditions. We developed a model consisting of three groups of CA3 neurons. We used this model to test two theories in three environments (small, medium, and megaspace). The first theory relies on neurons shared between fields that propagate activity from one subfield to another, achieving multi-field activity through increasing connectivity. The second theory relies on the projections of the inhibitory neuron onto the shared neurons, multi-field emerge as a function on inhibitory decrease in activity. Our results make specific predictions about the possible mechanisms that yield multi-field properties in megaspace and may provide sufficient support for new animal experiments to further test our hypothesis.