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.


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

  • Characterization of Small Molecule Inhibitors of CLKs and DYRKs

    Thorne, Curtis; Gonzalez, Lucia; Paek, Andrew; Wilson, Justin E. (The University of Arizona., 2023)
    Colorectal cancer (CRC) used to be known as a disease of old age, but now it is becoming a concern for younger adults. Researchers are unsure why, but they believe it may be due to environmental factors that lead to genetic changes in the colonic epithelium. These genetic changes affect essential signaling pathways, making them a crucial research focus. The Wnt signaling pathway is significant in maintaining digestive tract homeostasis but is often dysregulated in cancer. For this reason, researchers are working to identify proteins that affect Wnt signaling and target them with inhibitors. The CLK and DYRK kinase families are a group of proteins closely linked to the Wnt signaling pathway and implicated in disease. In this study, I tested 107 novel small molecules that are CLK/DYRK inhibitors in a dose-response curve with human colonic epithelial cells (HCECs). From this data, we identified six top compounds that were tested further in a cell viability assay to determine their efficacy against cancer cells. We also immunoblotted for CLKs' substrate to understand how the compounds work and obtained pharmacokinetic data to understand their biomechanics. Ultimately, two promising compounds emerged as potential candidates for further organoid profiling – DYR726 and DYR895. We are especially excited for DYR895 to be FDA-approved soon, but we will also further assess DYR726
  • Assessing the Potential for Hemp to be Used in the Bioremediation of Soils Containing Perfluoroalkyl Substances (PFAS)

    Recsetar, Matthew; Dusza, Nicholas Bernard; Farrell-Poe, Kitt; Babst-Kostecka, Alicja; Brusseau, Mark (The University of Arizona., 2023)
    Widespread industrial and commercial use of perfluoroalkyl substances (PFAS) has led to their accumulation in soil, groundwater, and freshwater supplies. The high stability of PFAS has rendered many traditional methods of remediation largely ineffective or too expensive to implement. This study seeks to quantify the efficacy of hemp as phytoremediator of soil contaminated by wastewater biosolid containing PFAS. Twenty hemp plants were cultivated using Arizona desert soil and mixed with biosolid contaminated with PFAS. The biosolid was incorporated into the soil at varying loading rates: 0%, 5%, 15%, and 30% biosolid by volume. Biosolid treatment groups consisted of five cannabis plants that were kept in a state of vegetative growth for 16 weeks. Initial soil samples were taken from the homogenized biosolid treatment mixtures before planting and compared with the final soil samples obtained from each plant to assess changes in PFAS levels. After harvest, plant tissue samples were taken from the roots, stems, and leaves for PFAS analysis. Plant growth metrics (height, stem diameter and number of axials) were recorded weekly for each plant. The plants grown in 5% biosolid by volume exhibited the greatest height and largest average stem diameter. The plants grown in 15% biosolid mixture appeared to be the healthiest and had greater biomass. The experiment unveiled significant translocation of PFOA and PFBS into various regions of the plants in all biosolid treatments. Specifically, within treatment #1 and treatment #2, 20.56% and 49.06% of the PFOA from the initial soil samples were translocated into the roots of plants, respectively. The types of PFAS that tend to be taken up by the plants are water soluble and tend to leach through soil. PFOS was found to be filtered out of samples by solid phase extraction ENV cartridges and were not translocated into the plants.
  • A Novel Kappa Opioid Receptor Antagonist with Prolonged Duration of Action

    Porreca, Frank; Navratilova, Edita; Redman, Paula; Kopruszinski, Carol (The University of Arizona., 2023)
    The history of opioid use traces its roots back to ancient civilizations, where substanceslike the opium poppy (Papaver somniferum) were harnessed for their remarkable analgesic properties. Today, the conventional analgesic option is opioids that target the mu opioid receptor (MOR), however, they are associated with deleterious effects, such as the development of dependence and respiratory depression. However, the kappa opioid receptor (KOR) subtype, found on the surface of cells particularly in the brain and spinal cord, promotes the negative affect of chronic pain and blockade of KOR signaling would be therapeutically desirable. KOR antagonists including CYM53093 (i.e., Navacaprant, former BTRX-335140 and NMRA-140) are in advanced clinical development for the treatment of severe depression, anxiety and anhedonia but require frequent dosing for beneficial effects due to their relatively short duration of action. This poses challenges for patient adherence and increases treatment costs. Developing longer- acting formulations is crucial to enhance convenience, adherence, and cost-effectiveness in managing conditions like generalized anxiety, major depressive disorder, pain and its comorbidities. This study pharmacologically evaluated the potential of longer-acting temporal profile for novel KOR antagonist, CYM3063, in mice.
  • Adapting the Differential Target Antenna Coupling (DTAC) Method to Commercial Geophysical Exploration Equipment

    Sternberg, Ben K.; Wang, Zida; Ferre, Paul A.; Heath, Gail (The University of Arizona., 2023)
    The Differential Target Antenna Coupling (DTAC) method is a newly developedelectromagnetic method that has been thoroughly studied using different array setups, such as horizontal array, vertical array, and fixed transmitter loop with moving receiver. However, all previous studies were conducted using laboratory equipment, which is not suitable for real-world survey’s needs. The primary objective of this paper is to adapt the DTAC method using equipment from Zonge International, a well-known geophysical equipment manufacturer worldwide. To achieve this goal and accommodate the limitations of a small-sized field crew used for this project, a newly designed compact version of the vertical array DTAC setup was built. This setup includes a 6m-by-6m transmitter loop and a 3-axis receiver coil. Field tests were conducted in a well-studied test site with a known target, along with numerical simulations using EMIGMA software as the benchmark. The results demonstrated that the DTAC method with Zonge International’s geophysical equipment offers significant advantages over conventional electromagnetic methods. This validates that the DTAC method is suitable for real-life exploration surveys. Additionally, this paper discusses a possible real-life field exploration setup and procedure that can be adapted for a larger field crew and a larger transmitter loop.
  • Alveolar Type 1 Epithelial Cell Deficiency in Pulmonary Hypertension

    Dai, Zhiyu; Hamid, Syed; Dai, Zhiyu; Gonzales, Rayna; Wang, Dong (The University of Arizona., 2023)
    Rationale: Pulmonary Arterial Hypertension (PAH) is a severe health condition that involvesan ongoing process of pulmonary vascular resistance and vascular remodeling. These changes can eventually cause right heart failure (RHF) and in severe cases and can eventually result in death. AT1 cells mediate gas exchange in the lung. However, the connection between AT1 cell dysfunction and the onset of pulmonary hypertension (PH) is still not well-understood. A better understanding of the mechanisms could help the improvement of treatment for PAH. Objectives: To investigate the role and underlying mechanisms of AT1 cell deficiency in the pathogenesis of PAH. Methods: To determine whether AT1 cells are deficient in the development of PAH, lung sections from idiopathic PAH (IPAH) and control donors, as well as lung tissues from PH mice model Egln1Tie2cre (CKO) mice and wild-type (WT) mice, were evaluated for the expression of AT1 cell markers. Reverse Transcription-quantitative PCR (RT-qPCR) was performed in mice samples, to determine the expression levels of AT1 cells markers (Ager, Aqp5, Hopx, Rtkn2) using lung tissues from CKO and WT mice. Western blot analysis was then performed to quantitatively evaluate AT1 cell marker protein levels (Ager, Hopx) in lungs from CKO and WT mice. Immunofluorescence staining was applied using HOPX in both mice lungs and human IPAH lungs. Additionally, the expression of VEGFA, AT1 derived factor, was determined using the RNAscope technique on human IPAH and control lungs. Results: The findings of this study showed the mRNA levels of AT1 markers including Hopx and Rtkn2 were downregulated in CKO mice. The expression levels of AT1 markers Ager but not Hopx was downregulated in CKO mice by Western Blot. A decrease of AT1 cells assessed by quantification of HOPX in the IPAH human samples and CKO mice was observed in Immunofluorescent staining. Lastly, upregulated VEGFA expression in IPAH human samples were recorded as revealed by the RNA scope. Conclusion: The findings of this study demonstrated that there is a deficiency of AT1 cells in PAH patients and PH mice. Deficient AT1 cells might lead to impaired regeneration of the pulmonary vasculature and the development of PAH. Our study might provide a novel concept to treat PAH patient via studying the AT1 cells and their underlying signaling.
  • Comparing Microbial Source Tracking Methods for Precision and Reliability

    An, Lingling; Kazemi, Mohadeseh; Watkins, Joseph C.; Zhang, Hao (The University of Arizona., 2023)
    Microbiome research has experienced remarkable growth in recent years, driven by advances in DNA or RNA sequencing technologies and our deepening understanding of the critical roles that microbiota play in diverse ecosystems, including the human body. The term "microbiome" refers to the entire collection of microorganisms in a given environment, whether that is the gut of a human, the soil in a forest, or the water in an ocean. These microorganisms encompass bacteria, viruses, fungi, and other microbes, all of which collectively influence the health and functioning of their host ecosystem. The complexity and diversity of microbiome data have led to the development of various decomposition methods, each tailored to tackle the specific challenges posed by different environments and research objectives. Numerous tools have been developed to estimate the proportion of different contamination sources within a mixture. In this study, we evaluate the accuracy of various source tracking methods using datasets from microbiome studies. In addition to assessing source tracking methods, we also incorporate two widely used cell type deconvolution methods, namely EPIC and PREDE, which are designed to identify missing cell types in a given dataset. Furthermore, we investigate the effectiveness of combined methods by integrating RAD, a source tracking method aimed at filtering out unimportant sources, with either EPIC or PREDE for enhanced accuracy in both source tracking and cell type deconvolution. This research represents a pioneering effort to examine the application of cell type deconvolution methods in source tracking and vice versa. Particularly noteworthy is our focus on scenarios involving missing sources or cell types in the reference data, shedding light on the intricate interplay between these two analytical domains.
  • Potential Role of Acetylpolyamines in the Prostatic Tumor Microenvironment

    Miranti, Cynthia; Cernyar, Brent; Pandey, Ritu; Gelmann, Edward (The University of Arizona., 2024)
    Prostate cancer is the most common cancer in men excluding non-melanoma skin cancer, and the second leading cause of cancer-related mortality after lung cancer. Early stages of prostate cancer are dependent on androgen for proliferation and survival, and can be curable with standard surgical or radiation treatment options. Unfortunately, recurrent and metastatic prostate cancer is highly refractory. Eventually the disease will develop castration resistance which is incurable with our currently available androgen deprivation therapies and chemotherapies. Initially, immunotherapy in preclinical trials showed promise in activating the innate and adaptive immune system to target prostate cancer cells. While sipuleucel-T and pembrolizumab have been approved by the FDA for the treatment of asymptomatic or minimally symptomatic metastatic castration resistant prostate cancer patients, immunotherapies have overall shown only modest efficacy in clinical practice. Prostate tumors are heterogeneous and considered an immunologically “cold” tumor due to low expression of neoantigens and low tumor mutational burden, creating a significant obstacle to treatment with immunotherapy. In addition, the prostatic tumor microenvironment secretes factors that recruit an abundance of anti-inflammatory tumor associated macrophages (TAM), increases regulatory T cell infiltration, and activates immature myeloid cell differentiation to myeloid derived suppressor cells. These cells create an immunosuppressive barrier which inactivates cytotoxic T cells and prevents natural killer cell permeability. As of yet, we are unable to explain the abundance of infiltrating tumor associated macrophages associated with metastatic prostate cancer tumors. One factor may be acetylated polyamines released by prostate cancer cells into the tumor microenvironment. Classically, literature reports decreased total intracellular polyamine concentration with prostate cancer progression, suggesting polyamines have anti-tumorigenic properties. However, aggressive prostate cancer cells are shown to have a significant elevation in the message, protein, and activity of enzymes that direct polyamine metabolism. Interestingly, major studies that report decreased total polyamines levels in prostate cancer do not take into consideration the acetylated forms of these molecules, which is an alteration necessary for polyamine efflux and catabolism. Therefore, it would be reasonable to discuss how dysregulated polyamine metabolism in prostate cancer cells likely results in increased acetylpolyamines, as this may provide new insights into potential roles of these molecules in the prostatic tumor microenvironment. This review will focus on common mutations in prostate cancer that increase enzymes involved in polyamine synthesis and acetylation, reported impact polyamines have on varying mechanisms in immune cells that promote an immunosuppressive milieu, and highlight possible therapeutic targets that could increase the efficacy of currently available immunotherapies.
  • Oxygen and Glucose Therapy Improves Fetal Growth and β-cell Function in FGR Fetal Lambs

    Limesand, Sean W.; Varela, Mariangel; Craig, Zelieann; Goyal, Ravi (The University of Arizona., 2024)
    Babies born small for gestational age are more vulnerable to developing non-communicablediseases like glucose intolerance, obesity, and type-2 diabetes. Fetal growth restriction (FGR) occurs when the fetus is unable to grow to its full genetic potential and affects 3-7% of all pregnancies. FGR is often induced by placental insufficiency (PI-FGR) and accounts for a majority of babies born SGA. Placental insufficiency is characterized by poor placental transport of nutrients and oxygen to the fetus. In a previous study, we supplemented oxygen and glucose to PI-FGR fetal lambs in late gestation and showed improvements in their glucose homeostasis after 5-days but did not measure fetal and β-cell growth directly. In this study we supplemented glucose and oxygen for 10 days in PI-FGR sheep fetuses to determine whether raising glucose and oxygen concentrations to reverse the effects of PI could increase fetal and β-cell growth. Placental insufficiency was created with maternal heat stress during mid-gestation. For the experimental FGR fetuses supplemented with oxygen and glucose (FGR-OG), arterial oxygen and glucose were increased to near normal concentrations through maternal trachea insufflation of oxygen and an intravenous fetal glucose infusion. FGR-OG fetuses were compared to FGR fetuses receiving air and saline-infusions (FGR-AS) and control fetuses. Throughout treatment, thoracic circumference of each fetus was measured to visualize growth linear growth rates. After eight days of treatment, a square wave hyperglycemic clamp was performed to measure glucose stimulated insulin secretion (GSIS). At the end of treatment (day 10), fetal pancreata were collected and immunostained for insulin and phosphorylated Histone H3 to measure β-cell area and proliferation. After 24 hours of treatment, fetal thoracic circumference rates increase to rates comparable to control fetuses, which continued for the remainder of the treatment. As previously shown glucose stimulated insulin concentrations were low in FGR-AS fetuses but increased in FGR-OG fetuses to levels not different than control concentrations. In addition, β-cell proliferation rates also increased to rates not different than control β-cell proliferation rates. These findings show that continuously supplementing both oxygen and glucose to the FGR fetal lamb improved fetal and β-cell growth and insulin secretion responsiveness following the onset of PI-FG.
  • Incompressible Miscible Rayleigh-Taylor Instability Experiments on the University of Arizona Linear Induction Motor Drop Tower Using Planar Laser Induced Fluorescence

    Jacobs, Jeffrey W.; Withers, Clayton James; Craig, Stuart A.; Schluntz, Justine (The University of Arizona., 2023)
    Incompressible miscible Rayleigh-Taylor instability (RTI) experiments are described that utilize the University of Arizona’s vertical Linear Induction Motor (LIM) drop tower. RTI is a buoyancy driven instability occurring at the interface between two fluids of differing densities, represented by the Atwood number, where a destabilizing acceleration causes initial perturbations along the interface to develop into characteristic spike and bubble formations. The incompressible fluid pair used in the research is a miscible combination of isopropyl alcohol solution and calcium nitrate salt solution. Experiments were conducted at Atwood numbers of 0.150 and 0.216. The experiments conducted at an Atwood number of 0.216 are used as a replication of previous research to allow comparisons to the experiments conducted at Atwood values of 0.150. The fluid solutions used in experiments conducted at the Atwood value of 0.150 have been initially mismatched in refractive index as part of an examination of possible techniques for improving imaging issues commonly experienced by miscible experiments. An acrylic tank attached to an experimental aluminum reaction plate is mounted to the LIM drop tower and filled with the two fluids in an initially stratified configuration. The reaction plate, along with the fluid tank and diagnostic equipment, is vertically raised to the top of the LIM drop tower and subsequently accelerated downward at an effective constant acceleration of approximately 11.7 g, developing the fluid instability. Acceleration is accomplished by the interaction between the LIM drop tower’s parallel set of linear induction motors and the aluminum reaction plate that is vertically constrained within the rails of the drop tower. Deceleration is accomplished with a set of permanent magnetic brakes located at the base of the LIM drop tower. Acceleration is recorded using a single axis accelerometer mounted to the experimental test sled. Imaging equipment is rigidly attached to the test sled and provides visualization from a static viewpoint of the experimental tank. Both unforced and forced experiments are conducted, where an electrically driven actuator is used to provide vertical parametric forcing of the experimental test sled. Experiments are imaged using planar laser induced fluorescence (PLIF) to visualize the instability interface. A swept 445nm laser light beam that illuminates fluorescein dye mixed into the calcium nitrate solution allows planar visualization of the instability interface and experimental images are captured using a monochrome high-speed shock-rated digital camera that documents the experimental process. Resulting images expose a single plane of the developing RTI. Postprocessing follows in which a pixel level concentration profile is obtained. The concentration profile is used to provide measurements of the mixing process. From the concentration profile, a mixing region width is extracted and subsequent measurements of the instability growth constant, α, are obtained. Two methods for calculating α are used. Calculated α values for experiments at an Atwood number of 0.150 are in the range of 0.076–0.118 and the α values for Atwood numbers of 0.216 are in the range of 0.021-0.063, depending on measurement method. Comparisons of the measured α values to α values from previous experiments are made, noting that the reported α values are higher than what might be typically expected for similar experiments. A spectral analysis to examine the prevalent wavelengths during the experiment is completed and finds that forced experiments featured earlier development of dominant wavelengths when compared to unforced experiments. An analysis of the effects of refractive index variation on image sharpness using gradient-based focus measures is performed, but considered inconclusive.
  • Experiments on the Three-Layer Richtmyer Meshkov Instability

    Jacobs, Jeffrey; Schalles, Mark David; Craig, Alex; Chan, Cholik (The University of Arizona., 2024)
    The Richtmyer-Meshkov fluid instability (RMI) can be considered a particular case of the broader Rayleigh-Taylor instability (RTI), in the situation that the fluid interface is impulsively accelerated, as is the case when such an instability is impacted by a shock wave. The study of RMI has significant applications to the research of the Internal Confinement Fusion (ICF) method of nuclear fusion, which involves the superheating of fuel contained within a capsule consisting of multiple, closely spaced layers of material each affected by the formation of such instabilities under such conditions. One important quantity studied in RMI applications is that of the growth in amplitude of the instability structures as they develop from an initial sinusoidal perturbation at the interface, and this property is the main focus of the experiments conducted for this study. The effect of placing a secondary, unperturbed interface just above the well-studied single-interface configuration is studied for its effect on the amplitude growth in the nonlinear regime of RMI. The effects of the presence of this secondary interface are considered with two different gas combinations all of varying density, with a third gas added for a second interface and studied alongside the results of the one-interface case. The gases are vertically stratified in a shock tube with the lightest gas entering at the top, the heaviest gas at the bottom, and the middle layer gas emitted through porous metal plates near where the interface is formed. Experiments are visualized by illuminating one gas seeded with particles with a light sheet from a pulsed laser, with recordings captured by a single high-speed video camera. Amplitudes are measured by defining the interface position at each frame by its maximum brightness gradient and finding its maximum vertical span. The data suggests that the presence of the second, unperturbed interface causes a decrease in amplitude growth during the nonlinear regime of the instability development. Continued research is proposed to explore the accuracy of and reasons for the observations made.
  • Platelet Activation: Association with NADPH Oxidase Expression and Reactive Oxygen Species Generation in High-Shear Environments

    Slepian, Marvin J; DiCaro, Michael Vincent; Singh, Aditi; Lybarger, Lonnie (The University of Arizona., 2023)
    Thromboembolic complications remain a major cause of morbidity and mortality among patients with mechanical circulatory support devices for heart failure. Mechanical circulatory support devices, including ventricular assist devices (VADs), artificial hearts, and other cardiovascular therapeutic devices, produce significant intravascular shear which leads to turbulent blood flow and enhanced thrombotic activity. Reactive oxygen species (ROS) have been implicated as inflammatory mediators of platelet activation and thrombosis. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase plays an important role in ROS production. To further evaluate the role of NADPH oxidase 4 (NOX4) and ROS in shear conditions seen in VADs, this study examined the effect of hemodynamic shear stress on NOX4 expression and subsequent production of ROS in human platelets with fluorescent immunostaining to show NOX4 localization. Additionally, this study explored the effect of hydrogen peroxide (H2O2) on shear-mediated platelet activation. Correspondingly, ROS levels were positively correlated with an increase in NOX4 expression; excess ROS most likely resulted in exacerbation of shear-mediated platelet activation. Also, H2O2 resulted in an additive effect on shear-mediated platelet activation. Our results suggest a possible link between shear-mediated activation of platelets and NOX4-induced ROS production. Shear-mediated platelet activation is a dynamic process involving multiple biologic and mechanical elements. These findings contribute to a better understanding of thrombotic complications in patients with flow-altering implantable cardiovascular devices.
  • Sizing a Space Telescope for Exoplanet Studies: A Systems Engineering Case Study

    Douglas, Ewan; Carter, Alex; Ingraham, Patrick; Chalifoux, Bandon (The University of Arizona., 2024)
    Systems Engineering is an involved and non-standardized process that can vary dramatically even within different parts of the same project. Here I present a case study for applying systems engineering techniques to an optomechanical problem for a space based telescope. This telescope is being used to study exoplanetary systems and is very similar in concept and in design specifications to the Nancy Grace Roman Space Telescope. It includes active wavefront control and a coronagraph to improve the exoplanet detection capabilities. Here I discuss the design decisions that went into determining the appropriate size for the primary mirror of the telescope. The end goal is to have a telescope primary that is sufficiently large to obtain signal to noise ratios required to detect exoplanets. The process I used here involved preliminary orbital design work for the telescope, understanding the behavior of the rest of the optics within the telescope system, the output and geometry of the target planetary systems, and balancing the desired SNR with reasonable design constraints on the size of the primary.
  • P-Glycoprotein’s Role in Anti-Retroviral Drug Delivery Across the Blood-Brain Barrier To Combat Human Immunodeficiency Virus (HIV)

    Lybarger, Lonnie; York, Larry; Diaz Fuentes, Erika; Fantry, Lori; Munoz-Rodriguez, Jose (The University of Arizona., 2023)
    HIV continues to be a significant worldwide public health concern, with millions of deaths to date and ongoing transmission in all countries. It is challenging to cure because the virus remains within stable reservoirs that evade detection by the immune system. While the available treatments for HIV are effective, there are many options that have poor penetration across the BBB (blood-brain barrier). Treating the infected immune cells found in the CNS (central nervous system) is a challenge because patients are able to have undetectable viral load tests in the blood despite having dormant HIV reservoirs elsewhere in the body. This leads to a chance for these individuals with HIV to experience a range of cognitive, motor, and/or mood issues referred to as HIV-Associated Neurocognitive Disorder (HAND). However, as shown in Figure 1, the context of awakening these reservoirs using a Trojan horse-like method specifically targeting P-glycoprotein (P-gp) in the BBB, an efflux transporter, may provide important insight into decreasing the incidence of HAND. This diagram illustrates the typical situation of an HIV-infected person receiving treatment and the role of P-gp in preventing the drug from penetrating the BBB. The diagram is adapted from Al Rihani, Sweilem B., et al. "Disease-Induced Modulation of Drug Transporters at the Blood–Brain Barrier Level." International Journal of Molecular Sciences 22.7 (2021): 3742. Print.
  • A Regression Analysis of Impostor Phenomenon and Gender and Competence Motivation

    Smith, Eric D.; Demaree, Morgan Genieva; Legg-Burross, Heidi; Kersting, Nicole (The University of Arizona., 2023)
    Impostor phenomenon is a motivational construct described by an inability to internalize success, persistent self-doubt coupled with a sense of not belonging. The phenomenon is measured inconsistently, as researchers continue to use a scale based on outdated understandings of gender identity. In this thesis, I used two logistic regressions and two linear regressions to assess if a newer scale focused on competence motivation, the Self-Perception Profile for Adults is predictive of a scale historically used to measure impostor feelings of adults (Clance Impostor Phenomenon Scale). I recruited a sample of undergraduates (N = 167), which is a population that tends to have high rates of impostor-like feelings. These participants took an online survey in which they responded to scales measuring impostor-like feelings along with a scale measuring competence motivation. Using the method of scoring impostor-like feelings on a continuous was most informative. Physicality, home management, sense of humor, intelligence, and global scores of the self-perception scale were predictive of the participant’s level of impostor.
  • Development of Monitoring Tool for Managing Tospovirus Damage To Lettuce

    Carriere, Yves; Rodriguez, Shianna; Palumbo, John; Matzkin, Luciano (The University of Arizona., 2024)
    Impatiens Necrotic Spot Virus (INSV) is a recently introduced, thrips-transmitted tospovirusaffecting lettuce (Lactuca sativa) production in Yuma, Arizona. Since its discovery in Spring 2021 in Yuma, INSV has occurred every year, with incidences as high as 8% symptomatic lettuce plants at harvest during this study conducted in 2022-2023. Using RT-qPCR of lettuce plants, we detected the Tomato Spotted Wilt Virus (TSWV) in co-occurrence with INSV for the first time in Yuma in Spring 2022. However, RT-qPCR of lettuce plants and western flower thrips (Frankliniella occidentalis) populations did not detect TSWV in 2023. RT-qPCR of field-collected thrips coupled with bioassays evaluating their capacity to generate INSV symptoms in petunia leaf disks indicated that amplification of INSV primers alone can overestimate the thrips capacity to generate INSV symptoms in plants. To better evaluate the vectorial capacity of field-collected thrips, we developed a method based on amplification of primers for INSV and a reference gene in groups of individuals containing a known proportion of INSV-free thrips and thrips with empirically established positive vectorial capacity. This method was effective in detecting percentages of vector competent thrips as low as 0.5% (i.e., 1 vector competent individual out of 199 non-infected individuals). In February and March of 2023, surveys of 15 romaine lettuce fields with pairs of yellow sticky traps and transplanted petunia plants placed at the border of fields revealed that petunia plants captured a similar number of thrips as sticky traps. However, the petunia plants did not develop symptoms of INSV infection during the three weeks, even when vector competent thrips were detected on the petunia plants and in adjacent sticky traps. The proportion of vector competent thrips found in sticky traps and on petunia plants was not different. The vector manipulation hypothesis predicts a preference of non-virulent vectors for infected host plants and a preference of virulent vectors for non-infected host plants. We found that the distribution of virulent and non-virulent thrips on INSV-infected and non-infected lettuce plants in the field was consistent with this hypothesis. A key objective of this study was to determine whether INSV damage in lettuce fields at harvest can be predicted by monitoring INSV-competence in thrips and their population density early in the growing season. For each of 3 weeks of sampling, we calculated the risk of virus transmission in the 15 lettuce fields as the product of the number of thrips collected and the estimated proportion of INSV-competent thrips captured in yellow sticky traps at the border of the fields. For each of the three weeks, there was no significant positive association between the risk of virus transmission and the percentage of INSV-symptomatic lettuce plants at harvest. Sample size and the incidence of INSV infection in lettuce fields was relatively low in this study. Accordingly, more work is needed to evaluate whether the risk of virus transmission as estimated here can be used to forecast INSV damage in lettuce fields at harvest.
  • The Effects of Chronic Vaping Delta-9-Tetrahydrocannabinol (THC) in Traumatic Femur Fracture in Mice

    Vanderah, Todd; Trejo, Joseph; Lybarger, Lonnie; Thompson, Austen (The University of Arizona., 2023)
    The growing trend of vaping delta-9-tetrahydrocannabinol (THC) has raised concerns about its potential effects on various aspects of health. Extensive research has delved into the adverse effects of tobacco smoking on wound and fracture healing in both animals and humans. Concurrently, the growing prevalence of nicotine e-cigarette use has prompted studies to explore the repercussions of e-cigarette vaping on bone health, but the potential effects of vaping THC on bone healing remain a topic of scientific inquiry. As vaping has become increasingly popular, substantial concerns have emerged regarding its potential health risks, especially among adolescents. We utilized THC vape distillate with a total THC purity of 93.4% obtained from an Arizona State Licensed Dispensary. In our study we report the effects of chronic THC vaping (18.68 mg/mL) on bone healing following a traumatic femur fracture in mice, comparing the outcomes to those of non-exposed fracture mice. We also investigated the impact of both chronic and acute vaping of THC (18.68 mg/mL), nicotine (5 mg/mL), and chronic vehicle in the absence of fracture. The analysis includes the evaluation of callus size, serum levels of bone turnover markers (OPG/TRANCE,RANKL) and bone microstructures. Radiograph imaging showed THC exposure in mice with a fracture of the femur initially resulted in a greater callus diameter 1 week post-fracture compared to non-exposed fractured mice. The diameter of the callus was reduced at 2 weeks post-fracture and sustained this characteristic through 8 weeks post-fracture as compared to controls. Micro-computed tomography (µCT) revealed a significantly smaller callus volume in the THC-exposed fracture group compared to the non-exposed fracture group at 8 weeks post-fracture. Blood serum levels were analyzed for bone molecules, OPG and TRANCE(RANKL), that are crucial signaling molecules in fracture healing and bone homeostasis. Data revealed a non-significant change in OPG serum levels between both fracture groups, THC-exposed and non-exposed. TRANCE(RANKL) serum levels showed a statistically significant increase in the chronic THC-exposed fracture group compared to non-exposed fracture group and may be why a smaller callus diameter and volume was seen since TRANCE(RANKL) levels favor bone remodeling. In the absence of fracture, whether animals were exposed acute or chronically to THC or chronically to vehicle a non-significant change was seen in OPG serum levels. Similar results were obtained with chronic or acute vaping of nicotine. Of the available serums to measure, there was a non-significant change in TRANCE(RANKL) levels in animals exposed to THC or vehicle. Studies with nicotine vaping only included serum from two animals from each cohort, therefore samples were excluded in the statistical analysis of TRANCE(RANKL) serum levels. Taken together, our data demonstrates vaping THC at 18.68 mg/mL influences fracture callus size and TRANCE(RANKL) serum levels in animals that underwent a femur fracture. In the absence of fracture, vaping THC does not appear to influence OPG or TRANCE(RANKL) serum levels. Although preliminary due to a small number of animals tested, non-fracture µCT data revealed chronic nicotine vape exposure decreased trabecular marrow and spacing, while increasing trabecular bone volume fraction (BV/TV). Additionally, µCT data of the non-fracture groups showed that acute exposure to THC or nicotine and chronic exposure to THC or nicotine resulted in elevation in cortical BV/TV when compared to chronic vehicle exposure.
  • Academic Influence on Student Perceptions of Intersecting Issues: Wild Equine

    Mars, Matthew; OConnor, Arielle; Molina, Quintin; Torres, Robert (The University of Arizona., 2023)
    Higher education and learning have a direct influence on how students perceive environmental issues. Currently, little is known about how such influence shapes student perceptions of and attitudes towards protected equine on federally regulated land. This study explores range, wildlife, veterinary, and conservation biology undergraduate and alumni student perceptions of the regulation of protected equine populations through the lenses of disciplinary moral orders and academic culture. The study used a multiple-case design to qualitatively explore the level of influence of higher education and learning on student perceptions of issues pertaining to the federal protection of wild equine. Interviews with range management, wildlife biology, veterinary, and conservation undergraduate and alumni students at a large public research university in the southwestern United States were be conducted. The current study aimed to address the gap between moral order and academic cultures, and how these influences students’ perceptions on intersecting issues within their careers following higher education.
  • Evaluating Growth of Baby Leaf Spinach with Respect to Water and Salt Balance in the Arid Southwest United States

    Sanchez, Charles; Noon, Russell; French, Andrew; Rasmussen, Craig (The University of Arizona., 2023)
    Current literature for the irrigation management of spinach focuses on full season bunching spinach with little consideration given to the much shorter season baby leaf spinach. Baby leaf spinach represents an economically valuable crop in the desert Southwest US, and therefore would benefit from greater research into data driven management strategies. To overcome the challenge of the relatively short growing season of baby leaf spinach in plotting a crop coefficient (Kc) curve, the Kc curve is plotted instead as a function of both heat units after planting (HUAP) and Normalized Difference Vegetation Index (NDVI) as opposed to days after planting (DAP) as proposed in FAO56. Utilizing in-field measurements across 9 trial sites spanning 5 years, an initial Kc (Kc-INI) value of 0.90 and a mid-season Kc (Kc-MID) value of 1.00 were calculated. Due to the rapid growth of baby leaf spinach in such a short time, further investigations with greater temporal frequency will be needed to refine the capability of utilizing NDVI as a proxy to crop evapotranspiration (ETc). Additional work in this study looked at the water and salt balance of baby leaf spinach, with it being demonstrated that diminished yields occur in soils with salinity levels in excess of 7 dS/m. Irrigation management in baby leaf spinach has many opportunities for further research, but conclusions drawn in this study demonstrated that leaching salts during the baby leaf spinach cropping season are unnecessary and could be instead deferred to other times of the year.
  • Equilibrium Thermodynamic Modeling of Arclogites: Are We There Yet? An Example From The Andean Volcanic Zone (NVZ)

    Ibanez-Mejia, Mauricio; Ascencio, Porfirio Irepan; Quade, Jay; Mallik, Ananya (The University of Arizona., 2023)
    The Northern Volcanic Zone (NVZ) in the Andes is a continental magmatic arc emplaced in >50 km-thick continental crust. In S Colombia, a Pleistocene eruption known as the Granatifera Tuff exhumed a variety of (ultra)mafic xenoliths derived from lower-crust and mantle, providing a unique opportunity to study petrologic processes operating in the roots of the Andean arc. Here, we focus on garnet-clinopyroxenite (aka ‘arclogite’) xenoliths, which are lithologies expected to drive density instabilities in arcs. These rocks consist predominantly of garnet (30-57%) and clinopyroxene (20-66%), with amphibole as an additional primary phase (10-47%) in some cases.Phase equilibria modeling of pyroxenites using free-energy minimization tools such as MELTS has been shown to be troublesome, but more recent optimizations of thermodynamic databases are yet to be tested. We used Perple_X coupled with recent thermodynamic databases and solution models to calculate pyroxenite phase equilibria to: i) test the extent to which these results agree with phase relations and partial melting conditions of pyroxenites for which experimental data exist; ii) compare the results of the pyroxenite models from the NVZ with traditional thermobarometry, to confirm previous suggestions that the Mercaderes xenoliths represent a ‘hot’ end-member of arclogite localities worldwide; and ii) better understand the petrology and density structure of the lower NVZ arc. For amphibole-free xenoliths, we constructed P-T diagrams with garnet compositional isopleths to obtain P-T conditions. For amphibole-bearing xenoliths, we created isobaric T-X(H2O) diagrams using previous P estimates, to evaluate the predicted stability of amphibole as a function of water content. For all samples, diagrams were first created assuming all iron as ferrous (FeOT) from bulk-rock XRF data. Ferrous iron was then gravimetrically determined in whole-rock aliquots using potentiometric titration, and ferric iron contents were calculated using mass balance. With these results, new phase diagrams were recalculated using appropriate Fe2O3/FeO for each, to evaluate the effects of Fe speciation in the models. Our calculation results from MIX-1G, a pyroxenite for which extensive experimental data exist in the literature, yield better agreement between recent thermodynamic databases and experimental constraints than in the past, indicating that recent optimizations of thermodynamic data are more suitable for the study of nominally anhydrous pyroxenites. For amphibole-free (anhydrous) NVZ arclogites, we found the P-T conditions of low Fe3+/Fe2+ samples to agree well with previous P-T estimates when Fe2O3 is taken into account. However, the quality of compositional isopleth intersections degrades for samples with high Fe3+/Fe2+, indicating Fe speciation is an important parameter to consider in more oxidized arclogites but that existing solution models may not yet be completely reliable handling Fe3+ in these models. Calculation results for OCA-2, an amphibole-bearing pyroxenite for which experimental data exists, shows that phase assemblages and melting could not be replicated by the model. Furthermore, results from amphibole-bearing Mercaderes pyroxenites do not predict amphibole to be stable at the P-T conditions established from equilibrium thermobarometry, therefore precluding independent verification of the accuracy of the latter. From a more general perspective, our results indicate that modeling of amphibole-bearing arclogitic cumulates remains a challenge, and thus that P-T-X modeling of amphibole bearing arclogites using existing databases should be approached with caution or altogether avoided until experimental results can be shown to be accurately replicated.
  • Environmental Injustice in Guayaquil: An Analysis of Policies and Informal Settlements in a City that is Socially Resilient

    Robison, Clare; Martinez, Ibeth; Guerrero, Eduardo; Stoker, Philip (The University of Arizona., 2023)
    Mangroves are an essential ecosystem that helps prevent climate change. Examining the history of Guayaquil, we can observe that the historian Ycaza once stated, “Guayaquil is nothing more than a mangrove with the appearance of a city.” Tracing old maps in GIS and delving into the city’s history, we find maps depicting the former locations of mangroves. Informal settlements in Guayaquil have contributed to the deforestation of mangroves and the disappearance of estuaries. Despite the constitution recognizing inalienable rights to nature, thereby establishing it as a subject of law, deforestation of ecosystems is still occurring in Guayaquil. Although policies have attempted to prevent this, they have proven ineffective. A troubling cycle persists, where individuals claim land and later seek government legalization to make the area habitable. This cycle is both expensive and environmentally detrimental. This thesis examines the patterns of deforestation and formalization of settlements, challenging urban planners and designers to implement strategies for affordable housing at various scales and advocate for alternative models.

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