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  Progression

  Leslie, Kelly; Zimmermann, Karen; Ruiz, Deborah; McMahon, Ellen; Gubner, Jennie; See, Lydia (The University of Arizona., 2025)

  What began as research to understand dementia and cognitive decline became something much more personal: a way to process my own grief while navigating the complexities of my mother’s illness. This thesis, Progression, reflects these intertwined journeys. Using the stages of grief as a framework—shock, denial, anger, bargaining, depression, processing, and acceptance—this work explores the parallels between my mother’s cognitive decline and my emotional reckoning. Through a series of interactive prints, I invite viewers to engage not only with my story but with their own. This project is a space for reflection and connection, where personal experiences with loss, caregiving, and change can resonate universally.
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  Characterizing Hydroponic Dwarf Tomato Growth in Microbially Inoculated Lunar Regolith Simulant

  Hooks, Triston; Gelman, Adam William; Kacira, Murat; Hurwitz, Bonnie (The University of Arizona., 2025)

  Plant-microorganism interactions in crop production represent a critical and under-researched aspect of controlled environment agriculture (CEA) and bioregenerative life support systems (BLSS). Beneficial microorganisms have been shown to enhance plant resistance to pathogens, response to abiotic stress, and ability to uptake nutrients through the roots. The objectives of the current research were: 1) to demonstrate hydroponic crop production with lunar regolith for in-situ resource utilization (ISRU) within BLSS; and 2) to investigate the utility of microorganisms in hydroponic and BLSS via inoculation of lunar regolith simulant in a Bato bucket system. Dwarf tomatoes (c.v. Red Robin) were grown in coco coir-amended lunar regolith simulant (LRS) over 6 weeks, excluding germination and emergence stages, in a 2-factor factorial design (substrate x inoculation). Data was analyzed using SAS procedure GLM (general linear model) with least squares means and Tukey’s Honestly Significant Difference (HSD). Dwarf tomato ripe fruit yield and total fruit yield from plants grown in LRS was not significantly different from those grown in the control substrate (perlite), indicating that lunar regolith might be viable for ISRU within hydroponic crop production in BLSS. However, dwarf tomato shoot biomass (both fresh and dry weight) was significantly lower in LRS compared to perlite, indicating a negative impact to vegetative plant growth in lunar regolith that requires further investigation. Interestingly, the Brix (soluble sugar content) of ripe fruit was not significantly different between treatment groups, indicating a lack of plant salinity stress from the LRS which was another positive result. Finally, microbial inoculation showed no significant impact, either positive or negative, on any response variable measured and no significant interactions were found. Numerical patterns indicate that extending the duration of this type of study may reveal positive effects of microbial inoculation on plant biomass in both LRS and perlite, warranting further investigation.
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  Population Ecology and Conservation Translocation of the Narrow-Headed Gartersnake in Central Arizona

  Bauder, Javan M.; Roderick, Travis; Steidl, Robert J.; Ryan, Mason J. (The University of Arizona., 2025)

  The narrow-headed gartersnake (Thamnophis rufipunctatus) is a federally threatened species endemic to the Mogollon Rim in central Arizona and western New Mexico. This species has declined its range primarily due to habitat loss, degradation and invasive species. Additional information on this species’ ecology, particularly empirical estimates of movement and demographic parameters, are particularly important for the management and conservation of this species. We conducted a three-year mark-recapture study of narrow-headed gartersnakes in Canyon Creek in central Arizona. In chapter 1, we compared capture rates, individual growth rates, movement, and apparent survival between narrow-headed gartersnakes and a syntopic, non-imperiled species of gartersnake, the western terrestrial gartersnake (Thamnophis elegans). While we captured more western terrestrial gartersnakes during our study, we did not find marked differences between these two species in the metrics we examined. We also documented the successful application of passive PIT tag arrays for monitoring PIT-tagged gartersnakes. In chapter 2, we evaluated the post-release growth, movement, and apparent survival zoo-born narrow-headed gartersnakes from the Arizona Center for Nature Conservation/Phoenix Zoo’s breeding program and compared these metrics to those of wild narrow-headed gartersnakes. We released four different groups of zoo-born individuals representing two cohorts (young-of-year and holdover). We documented multiple instances of survival across one and two winters post-release by zoo-born individuals from The Arizona Center for Nature Conservation/Phoenix Zoo. We did not find marked differences between zoo-born and wild individuals although holdover individuals tended to have the greatest movement distances and lowest apparent survival. Our results can provide guidelines for the future use of conservation translocations for narrow-headed gartersnake recovery.
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  Modeling Growth of Chlorella sorokiniana by Changing CO2 Nutrient Concentration

  Ogden, Kimberly; Pajouyan, Armeen Robert; Saez, Eduardo; Flouda, Paraskevi (The University of Arizona., 2025)

  Algae research has gained significant attention due to its potential in carbon capture and biofuel production. Understanding the role of CO2 in algae growth is critical to optimize these processes. This study investigates the impact of CO2 on the growth of Chlorella sorokiniana under various experimental conditions. All experiments were conducted at a temperature of 35°C, a light intensity of 234 µmol m-2 s-1, and a 12-hour light window. For the main set of experiments, CO2 flow percentage was changed from 5% to only air flow to see the effect on growth rate. The results showed that excess CO2 doesn’t significantly affect growth, however when it is no longer in excess as concentration drops the growth rate decreases. A one-parameter model was applied to the data, providing values that accurately represent the data. In another experiment, the effects of CO2 flow being on always was compared with CO2 flow only being on during the light phase. The results supported the hypothesis that CO2 flow at night has a negligible impact on growth. In the final experiment, the flowrate of air was lowered while CO2 flow remained the same across both runs. This would be so that one run would have a total flow of 2 LPM and the other a total flow of 1 LMP. This is because although air flow is needed for oxygen content, excess can strip the CO2 from the reactor reducing efficiency. The results confirmed this as the 1 LPM experiment had a lower pH, meaning that there was more dissolved CO2 in solution.
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  Mexican Migrants Return South: Transborder Testimonials of Resilience and Adaptation in Mexico City

  Vásquez-León, Marcela; Carrión, Luis; Retis, Jessica; Bricca, Jacob (The University of Arizona., 2024)

  Migration from Mexico to the United States is a prominent topic in the U.S. and is the foundation for many political agendas and policy debates. However, return migration has received comparatively little attention in academia or policy initiatives. This thesis/documentary film examines the lived experiences of young adult Mexican return migrants in Mexico City, those with extensive histories in the United States who have been forced to return due to deportation or untenable living conditions as undocumented individuals in the US. Through an ethnographic research project, consisting primarily of a testimonial-based documentary film depicting the lives of return migrants, this study investigates transnational identity, liminality, structural violence, and the roles of community and resilience in adaptation to a new and unfamiliar country and culture. This project uses qualitative data from interviews, field observations, and video documentation to present a nuanced and candid view of how return migrants are forced to create a life in an unfamiliar place while at the same time giving rise to an emerging bicultural and transnational demographic in Mexico City.
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  Polychlorinated Biphenyl Contamination of Freshwater Fish From Military Sites in the Aleutian and Bering Sea Islands Region

  von Hippel, Frank; Demitrack, Zoe; von Hippel, Frank; Reynolds, Kelly; Yang, Yu (The University of Arizona., 2024)

  The biomagnification of persistent organic pollutants (POPs) in the arctic foodweb is a key concern of the Aleutian and Bering Sea Islands (ABSI) Initiative, a partnership dedicated to tackling the “unprecedented environmental change impacting the lives, lands, and waters” of the ABSI region. To address this concern, this thesis expands upon the current but limited knowledge of regional pollution of a signature POP, polychlorinated biphenyls (PCBs). PCBs are considered “probable human carcinogens” by the US Environmental Protection Agency (EPA)2. They are also associated with adverse neurological, reproductive, and immune system effects in animals. Through the process of global distillation, the Arctic serves as a hemispheric sink for PCBs used and manufactured at lower latitudes. Once in the Arctic, PCBs bioaccumulate and biomagnify in the lipid-rich arctic foodweb. Due to both global distillation and local sources of pollution such as military sites, arctic Indigenous people practicing a subsistence lifestyle are exposed to high levels of PCBs. Despite the ecological, cultural, and economic significance of the ABSI region, as well as regional reliance on a subsistence diet, little information exists on current and long-term regional trends in PCB contamination of important biota. The ABSI region was militarized during World War II and the Cold War. As a result of militarization, 51 formerly used defense (FUD) sites are scattered across 32 islands. FUD sites are known hotspots for POPs including PCBs, but the majority have not seen any remediation. The United Nation’s 2020 Arctic Monitoring and Assessment Programme report suggests that while atmospheric deposition of PCBs in arctic environments is decreasing, re-emissions from local sources, such as military sites, are becoming increasingly important. Little is known about the importance of FUD sites as sources of PCB contamination in the ABSI region. Identifying trends in long-range PCB contamination, as well as the role FUD sites play in local contamination, is vital to protecting the unique ecosystems and subsistence practices of the region. As such, the aims of this thesis are to: 1) provide a background and historical information on the Arctic and the ABSI region as it relates to PCB pollution; and 2) analyze PCB contamination in two freshwater fish species collected military and non-military sites throughout the ABSI region. Future work will include an examination of PCB contamination of fish and shellfish on Unalaska Island and a quantitative risk assessment based on contaminant concentrations in fish.
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  Bacterial Modulation of the Epithelial Barrier in Crohn's Disease

  Vercelli, Donata; Duhon, Dillon; Lybarger, Lonnie; White, Katie (The University of Arizona., 2024)

  Crohn’s Disease is a complex, multifactorial disorder induced by chronic, disproportionate inflammatory responses to the bacteria that reside in the digestive tract. One mechanism by which this inflammatory response is induced is a dysfunctional epithelial barrier, in which bacteria are exposed to the immune system in an unregulated fashion that leads to inflammatory-mediated bowel damage. As discussed in this thesis, the epithelial barrier is regulated by a number of different cell types, receptors, as well as the products of microbial metabolism. Microbial metabolites, such as short-chain fatty acids, indole derivatives, and secondary bile acids, have recently been elucidated to have significant physiological effects on the epithelial barrier. Thus, microbial metabolites may have useful implications as Crohn’s Disease biomarkers or as therapeutic agents in disease treatment and remediation.
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  A Constitutive Model for Simulating Weak Rock Mass Behavior

  Momayez, Moe; Azadi, Ava; Kemeny, John; Waqas, Muhammed (The University of Arizona., 2024)

  This thesis develops an advanced constitutive model for simulating the behavior of weak rock masses, which are often characterized by low strength and high deformability. Addressing the complexities inherent in geological formations, the model integrates key factors such as stress anisotropy, pore pressure, deviatoric stress, and thermal effects. Traditional models often fail to capture the nonlinear and probabilistic responses of weak rock masses under varied stress conditions. This study overcomes these limitations by employing Monte Carlo simulations combined with Weibull distributions to better reflect the variability and heterogeneity of geological properties. The model's validity is confirmed through a comprehensive comparison of simulated data with experimental results, employing statistical methods such as the Kolmogorov-Smirnov test and visual analysis techniques. The findings demonstrate that the proposed model accurately predicts the mechanical behavior of different rock types, such as Claystone, Mudstone, Sandstone, Shale, and Siltstone, under diverse loading scenarios. Practical applications of this model are highlighted in fields like mining engineering, geothermal energy, and oil reservoir management, where predicting rock mass stability and behavior is critical. While the model shows significant advancements over existing methods, it also acknowledges limitations and suggests areas for future research, such as incorporating long-term environmental factors and expanding empirical data calibration.
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  A Nation Trapped in Time

  Jens, Benjamin; Kelley, Catricia Galyn; Gordienko, Anastasia; Leafgren, John (The University of Arizona., 2025)

  This thesis explores the complex interplay of time and national identity in Soviet and post-Soviet Russia through the metaphor of a house. Structured around the elements of a house—floor, walls, windows, doors, and roof—this paper examines how time operates as the framework for constructing and containing identity. Drawing on literary and cinematic works, the study reveals how the floor symbolizes the past, the walls represent the present, the windows and doors signify transitions and possibilities for the future, and the roof encapsulates stagnation and unresolved trauma. By analyzing Yevgeny Zamyatin's We, Andrei Tarkovsky's Solaris, Natalya Baranskaya's A Week Like Any Other, and Svetlana Alexievich's Chernobyl Prayer and Secondhand Time, the thesis investigates the tension between historical memory and cultural evolution. Zamyatin’s We critiques the manipulation of historical foundations under totalitarian control, while Tarkovsky’s Solaris portrays the haunting of the present by unresolved pasts. Baranskaya’s works highlight the constrained opportunities for societal transition, particularly for women. Alexievich’s oral histories delve into the weight of collective trauma, depicting the roof of the house as a site of stagnation, where unresolved crises impede forward movement. The metaphor of the house of time offers a fresh perspective on Russian identity, emphasizing the necessity of confronting historical ghosts and engaging with cultural diversity to foster a more dynamic and inclusive future. This study demonstrates how the intersections of time, memory, and identity shape a nation’s struggle to navigate its past while envisioning new possibilities for growth and transformation.
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  Age, Sex, and APOE4: Insights into Metabolic Changes in a Novel Mouse Model of Late-Onset Alzheimer’s Disease

  Brintons, Roberta D.; Delatorre, Nicole; Rodgers, Kathleen; Wang, Tian (The University of Arizona., 2024)

  Late-onset Alzheimer’s Disease (LOAD) is a progressive and irreversible neurodegenerative disease characterized by memory loss, cognitive decline, and brain atrophy. Age, chromosomal sex, and apolipoprotein E (APOE) genotype are well-documented risk factors for the development of AD, each having a systemic impact and significant implications for disease progression. Understanding the interactions among these risk factors is essential to elucidate the underlying mechanisms of disease development. Prior to clinical onset, LOAD is preceded by a decades-long prodromal phase. Previous studies have suggested that metabolic dysregulation during midlife aligns with this prodromal period. We hypothesize that age, APOE genotype, and chromosomal sex interact to drive AD risk through mechanisms that extend beyond traditional amyloid and tau pathology, involving systemic metabolic dysregulation. Specifically, we propose that these factors shape sex- and genotype-specific metabolic profiles, with female APOE4 carriers exhibiting metabolic dysregulation, and earlier than their male counterparts. To test this hypothesis, we utilized a novel mouse model combining humanized amyloid precursor protein (hAPP) and apolipoprotein E (hAPOE) to investigate sex- and genotype effects on metabolic profiles, evaluating energy metabolism and circulating lipids. Our findings revealed significant sex-driven differences, with females demonstrating earlier metabolic changes. Female hAPP+hAPOE4 mice exhibited disrupted glucose and lipid metabolism, and lower circulating cholesterol. This study provides a novel investigation into the effects of age, sex, and APOE genotype in a LOAD risk mouse model. By utilizing a preclinical model expressing humanized APOE and APP without dominant, disease-causing mutations, we examined the nuanced effects of APOE4 metabolic regulation across aging in a potentially more translational context. Furthermore, this work emphasizes sex-driven metabolic changes, providing additional insight into the increased vulnerability to LOAD in females.
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  Automated Analysis of Scattering-based Light Sheet Microscopy Images of Anal Squamous Intraepithelial Lesions

  Kang, Dongkyun; Kim, Yong Jun; Sawyer, Travis; Subbian, Vignesh (The University of Arizona., 2024)

  Anal cancer presents diagnostic challenges, particularly in identifying high-grade squamous intraepithelial lesions (HSIL), with its increasing incidence and mortality rates. Current diagnosis methods, including cytology, biopsy, and high resolution anoscopy (HRA), provide important diagnostic information. However, cytology is often limited by suboptimal sensitivity and specificity, while high resolution anoscopy-guided biopsy is limited by its long processing times due to unnecessary biopsies and staining requirements. Scattering-based light sheet microscopy (sLSM) can offer an alternative approach by utilizing intrinsic tissue scattering properties to visualize morphologic features without the need for additional labeling or staining.In this study, we developed and evaluated an automated algorithm for analyzing 187 sLSM images obtained from 80 anal biopsies. The method employed a row-by-row binarization technique for nuclear segmentation, achieving high precision (0.97) and recall (0.91). Seven nuclear features, including nuclear intensity, intensity slope as a function of depth, nuclear-to-nuclear distance, nuclear-to-cytoplasm ratio, cell density, nuclear area, and proportion of pixels corresponding to nuclei were extracted and statistically analyzed. Among the seven features, six showed statistically significant differences between HSIL and non-HSIL (non-dysplastic or low-grade squamous intraepithelial lesion, LSIL). A linear support vector machine (SVM) was trained and tested using five-fold cross validation on these features. The classifier achieved a sensitivity of 90%, specificity of 70%, and area under the curve (AUC) of 0.89 for per-image diagnosis, and sensitivity of 90%, specificity of 80%, and area under the curve (AUC) of 0.93 for per-biopsy diagnosis.
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  Changes in Photosynthetic Net CO2 Assimilation Rates on Theobroma cacao L. From In Situ Artificial Leaf Warming: A Study in the Biosphere 2 Tropical Rainforest

  Hurwitz, Bonnie L.; van Haren, Joost; Blue, Bryan P.; Giacomelli, Gene A. (The University of Arizona., 2024)

  A 33-week long in situ leaf warming experiment was performed to determine the change in the rate of photosynthetic net CO2 assimilation rates (A) in the tropical understory species, Theobroma cacao L. (cacao) in the controlled environment of the tropical rainforest biome of Biosphere 2 (B2), Oracle, Arizona, USA. A sustained multi-week in situ leaf level temperature increase of 3 °C was performed to understand rate changes in A, stomatal conductance (gsw), evapotranspiration (E), and vapor pressure deficit at leaf temperature (VPDleaf). Three warming experiments were performed on two mature, fruit producing cacao trees from 17 November 2023 to 8 May 2024 . One leaf was heated using a custom designed leaf heating device where it was continuously heated to 3 °C above ambient leaf temperature; another had the same heating structure installed but not heated, and an ambient leaf used as a control. Sustained leaf warming at 3 °C caused a decrease in photosynthetic net assimilation rates (A), evapotranspiration (E), and stomatal conductance (gsw), and an increase in vapor pressure deficit at leaf temperature (VPDLeaf). Together, these indicated that heating the leaf caused a net photosynthetic decline, supported by the decreased gas exchange that would limit CO2 uptake, reduce A rates, and increase VPDleaf due to reduced E. The presence of the heating apparatus in the Unheated treatment showed mixed results, and no statistical conclusions could be drawn about its effect on the response of A and results did not significantly vary from the control leaf.
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  Deep Learning Models for Image-Based Damage and Microstructure Characterization in CFRP and CMC Composites

  Zhupanska, Olesya; Brelay, Adrian; Madenci, Erdogan; Uhlmann, Donald (The University of Arizona., 2024)

  As composite materials become more widely used in different industry fields other than automotive and aerospace, methods of investigating the microstructure are critical when testing the physical properties of the composite. Unlike metals, composites are made up of different material phases which cause them to fail and develop internal damage in unique ways. Micro computed tomography (micro-CT) has emerged as one of the most useful techniques to assess three dimensional (3D) microstructures and damage in composite materials. Machine Learning (ML) is becoming one of the essential tools used to analyze large volumes of experimental data in materials science. In this work, ML is used for automatic segmentation of micro-CT imaging data of low-velocity impact damage in carbon fiber reinforced polymer (CFRP) composites and of the microstructure and damage in ceramic matrix composites (CMCs). For CFRPs, deep learning models based on U-Net, BiSeNet, INet, and FC-DenseNet architectures were trained and refined to evaluate the accuracy of supervised ML compared to unsupervised ML. The unsupervised ML methods utilized statistical distances and greyscale threshold intensity segmentation to isolate damage in high-resolution image data. Results show that the Kullback-Leibler divergence is the most conservative and, thus, preferred statistical distance for unsupervised ML in CFRP composites. Furthermore, when comparing with the supervised ML models, FC-DenseNet provided the most accuracy but U-Net, which was the second most accurate, also provided much faster training and segmentation times. For CMCs, microstructure and damage in a minicomposite consisting of continuous silicon carbide (SiC) fibers embedded in a SiC matrix with boron nitride (BN) coating was investigated under a 40 N tensile load. Deep learning models based off of a 2.5D U-Net architecture were used to identify the different material phases and isolate cracks in the CMC minicomposite. A sequence of two-class semantic image segmentation models was created to isolate pores, fibers, fiber coating, and matrix, which were then used to build and train a five-class semantic image segmentation ML model. This model could identify fibers, fiber coating, matrix, pores, and background simultaneously. The segmentation results were analyzed to estimate volume fractions of composite phases and compared to literature values. Results show that prioritizing high contrast phases when training the U-Net model attained volume fractions that compared well to results reported in the literature. Furthermore, the use of deep learning models was investigated to determine their ability to identify and isolate matrix cracks within the microstructure.
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  Effective Expectations: A Binomial Approach Toward Predicting Auto Registrations

  Thompson, Gary; Addison, Paul Nathan; Shockey, James; Aradhyula, Sateesh (The University of Arizona., 2024)

  Automotive manufacturers sell their products to consumers through dealerships in a successive market structure. Manufacturers have a vested interest in both monitoring and influencing the behavior of the dealers who sell their products, but the methods by which this monitoring is accomplished can be improved by accounting for variation in local markets. Indeed, US courts have found that the current methods used to monitor selling behavior, called sales effectiveness, are unreliable and ill-suited for monitoring automotive dealerships. In this paper, a method is presented which provides predicted automotive registrations of particular manufacturers for local markets by employing a log-odds regression with demographic covariates. The methodology provides a marked improvement from the methods which manufacturers have historically employed.
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  From Functional Architecture to Cultural Heritage: Unveiling the Significance, Evolution, and Present Challenges of the Catalan Masia

  Robinson, Clare M.; Estrany Bover, Montserrat; Weinstein, Beth M.; Chorover, Gina (The University of Arizona., 2024)

  A Masia is a traditional type of construction that originated for agricultural purposes in the early 10th century in the northern Mediterranean side of Spain. This type of construction, also known as Mediterranean or Catalan farmhouse is the main building type in the Mas, an agricultural site composed of the main house (Masia), the agricultural land that surrounds it, forests, and ranches. For many decades, Masies were the center of family life, with members working the fields from a young age. They also served as early navigational landmarks in towns, before named roads and streets existed. Each Masia represented the family that owned it, and its name was often linked to nearby landscape features or other local elements. This naming tradition is why the names of these houses were commonly preceded by the words Cal, Can, Mas, or Ca (shortened forms of the Catalan word casa, meaning house), followed by either the family’s last name or notable features of the surrounding environment. In other words, Masos and Masies are, and should be considered as, “Spatial Biographies”. Understanding Masies as spaces that hold historical and cultural narratives essential to understanding the past and informing future activism. In recent decades, the expansion of urban areas, together with the agricultural policies of the European Union, and the changes in agricultural production, have led to widespread abandonment of these lands, severing the traditional relationship between the farmhouses and their fields. As a result, many Masies have been repurposed into summer homes, secondary residences, rural tourist accommodations, or left abandoned. This thesis examines the current state of these farmhouses, focusing on the challenges they face today. The survey included in this research is centered on Santa Eulàlia de Ronçana, a small town in the central-southern area of Catalonia, Spain. The methodology combines physical and theoretical approaches, including a chronological analysis to trace the historical events that contributed to the decline of vernacular landscapes and Masies, an evaluation of existing heritage protection policies in Spain, and a survey to determine the current condition of these buildings. Additionally, geospatial mapping and data collection are employed to gain a comprehensive understanding of the present rural landscape in a specific region. The findings of this research will target improvements in local heritage conservation policies and procedures, addressing a gap in the protection of Masies which has thus far remained underdeveloped. Furthermore, the study offers a better understanding and interpretation of the significance of these farmhouses to improve their conservation efforts, as well as their incorporation in rural development plans.
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  GABA-T Inhibition and Its Effects on the Progression of Hepatocellular Carcinoma and Aging

  Stern, Jennifer; Renquist, Benjamin; Ngu, Emily; Yao, Guang (The University of Arizona., 2024)

  Outside of its role in the central nervous system as an inhibitory neurotransmitter, ɣ-aminobutyric-acid (GABA) acts as a hepatokine within the liver. NAFLD is associated with increased risk of developing HCC. We have previously demonstrated obesity increases production and excretion of hepatic GABA. Furthermore, GABA can drive the progression of HCC. In regards to aging, obesity shortens lifespan and healthspan, thus contributing to accelerated aging. We performed two studies assessing the effects of GABA-transaminase inhibition on NAFLD-associated HCC and age-associated metabolic and physical declines. To assess the role of GABA within NAFLD-associated HCC, we created an accelerated diet-sensitive mouse model and targeted hepatic GABA production using ethanolamine-O-sulfate (EOS), a GABA-transaminase inhibitor. We found HCC decreased mRNA expression of the GABA shunt enzymes (GABA-transaminase and succinate semialdehyde dehydrogenase), decreased mRNA expression of export-type GABA transporters (SLC6A12 and SCL6A13), and decreased mRNA expression of GABA A receptor subunits. Overall, GABA-transaminase inhibition using EOS had no effect on tumor burden after 16 weeks of exposure to cancer-causing stimuli. To assess the role of GABA in aging, we tested measures of metabolic and physical performance in 6 months-old-, 12 months-old-, and 18 months-old mice. After administering EOS for 4 weeks, we observed modest improvements to glucose clearance, basal insulin, and all-limb grip strength in aged mice. Additionally, GABA-transaminase inhibition caused weight loss and lowered serum triglycerides in both young and aged mice.
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  Interparental Conflict, Support and Affection, and Coparenting Alliance Among Lower-Income, Unmarried Couples During the Transition to Parenthood

  Curran, Melissa; Aroz-Moscoso, Grace; Barnett, Melissa; Knapp, Darin (The University of Arizona., 2024)

  Guided by family systems theory and the spillover hypothesis, data from the Building Strong Families project was used to test how mothers’ and fathers’ constructive conflict, destructive conflict, and support and affection were associated with mothers’ and fathers’ coparenting alliance by utilizing a strengths-based approach. The study consisted of 1,516 different-sex couples from the United States who were primarily low-income, unmarried and experiencing the transition to parenthood when their children were around 36 months of age. The current study results are reported here, while noting that multiple tests of model fit yielded poor model fit; thus, the findings reported here should be interpreted with caution. The study findings provided support for family systems and the spillover hypothesis, specifically in regard to instances of positive spillover, such that higher constructive conflict and support and affection (e.g., partner encouragement) for both mothers and fathers was associated with higher coparenting alliance for both mothers and fathers. However, the current study did not find support for negative spillover seeing as mothers’ and fathers’ destructive conflict was not significantly associated with coparenting alliance. These results underscore the importance of including a variety of constructs, and reports from both mothers and fathers, to understand more about coparenting alliances for these families. Further, the current study highlights key areas within romantic relationships that, when strengthened, have the potential to positively spillover into other areas of the family.
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  Is Vigilance Something to Keep an Eye on? Understanding Ethnic Variance in Cardiovascular Disease Risk

  Ruiz, John M.; Ibarra Mevans, Amelia; Sbarra, David A.; Hamann, Heidi A. (The University of Arizona., 2024)

  Social vigilance, the active behavior of scanning one’s environment for possible interpersonal challenges or threats, is associated with the activation of stress responses related to downstream disease outcomes, including cardiovascular disease (CVD). Hispanics/Latinxs (H/L) living in the U.S. navigate significant economic, psychosocial, and physical stressors that may influence their vigilant behavior including high rates of poverty, neighborhood segregation, interpersonal discrimination, and poor healthcare access. Despite greater stress exposure, H/L exhibit relatively better physical health and lower mortality compared to Non-Hispanic Whites (NHW), a phenomenon known as the Hispanic Health Paradox. The sociocultural hypothesis suggests that collectivistic values within H/L communities may buffer stress perception, reducing the need for social vigilance. Related to culturally driven differences in health, Anglo acculturation, which is an individual’s sense of inclusion within English-speaking sociocultural contexts, has been shown to be related to worsening health status among H/L. To address possible ethnic differences in stress-related pathways to better health outcomes among H/L, our study aimed to test whether H/L display less social vigilance than expected compared NHW, and to examine differences in stress experience among ethnic groups as a pathway through which stress exposure is associated with social vigilance. Additionally, we explored if these differences were moderated by social support and acculturation. The current study assessed a subsample of H/L (n=1,297) and NHW (n= 1,118) young adults from a larger cross-sectional psychosocial survey across the U.S. Results revealed that H/Ls reported lower social vigilance than NHW, with the differences primarily driven by Latina women in the sample. Stress experience mediated the relationship between stress exposure and social vigilance, suggesting that perceptions of stress influence the need for vigilance, though no differences were observed among racial/ethnic groups. Consistent with the sociocultural hypothesis, social support moderated this relationship for the H/L group. Additionally, Mexican orientation predicted lower stress experience, indicating that lower acculturation was associated with reduced social vigilance scores. Our findings supported our main hypothesis, consistent with the literature on stress appraisal processes and cultural stress-buffering effects of collectivism and the benefits of larger, tighter social networks.
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  Modeling Coherent Beam Combining Feasibility with Supercontinuum Sources

  Kieu, Khanh; Allured, Ryan; Newton, Elijah; Jones, R. Jason (The University of Arizona., 2024)

  Using numerical modeling methods, this thesis investigates the feasibility of coherent beam combining (CBC) using supercontinuum light generated by independent all-normal dispersion photonic crystal fibers (ANDi PCFs). Such a system would require a high degree of temporal coherence and near zero relative phase error over a large spectral bandwidth between multiple channels. Coherent supercontinuum can be achieved when pumping ANDi PCFs with a low noise mode locked source emitting very short pulses (∼200 fs or less). These conditions prevent noise-seeded processes like modulation instability and result in a spectrum generated solely through coherent effects such as self phase modulation. The generalized nonlinear Schrödinger equation is used to calculate the spectral and temporal pulse evolution through ANDi PCFs with realistic noise applied. The resulting shot-to-shot coherence and relative phase are calculated and used to evaluate the expected coherent combining efficiency. It was found that >90% combining efficiency over a 850-1250 nm bandpass could theoretically be achieved between two channels when the relative intensity noise limited (RIN) to <1% and all other parameters are identical. Similar performance can be achieved over a smaller bandpass of 450-600 nm when pumping at 515 nm in the presence of 2% RIN. Additionally, tolerances are established for static differences in peak powers, pulse durations, and fiber lengths between channels. Finally, relative phase compensation after supercontinuum generation is explored by using bulk glass dispersion compensation. Least squares optimizations are performed to determine the ideal thicknesses of various glass types to provide the best dispersion compensation for a particular relative phase shape. Results are reported for seeding the fiber near the minimum dispersion wavelength at 1030 nm and for visible supercontinuum generation at 515 nm.
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  Optimized Fidelity and Mobilization of an In-Vivo Photoacoustic Skin Imaging System

  Witte, Russell S.; Lima, Judson; Witte, Russell S.; Sawyer, Travis W.; Willomitzer, Florian (The University of Arizona., 2024)

  Biomedical imaging of skin cancers for evaluation and non-invasivetracking of progress to therapies has a gap in mainstream industry for lesions that present in deep dermal areas of the body. Optical imaging methods available have varying limitations when assessing between healthy skin tissue and different types of skin cancers deep within the tissue. Photoacoustic tomography (PAT) has gained popularity for its ability to provide specific tissue structure and composition at depths of 1 cm or greater. Data that can be resolved at sub 1 cm depths or can open a path in clinical imaging of lesions that is highly desirable. This master’s thesis lays out a variation of a cost-effective, second generation version of a portable clinical hybrid pulse echo (PE) and Photoacoustic tomography 3D imaging system that was originally developed for in-vivo assessment and monitoring of common cutaneous skin lesions in dermatology clinical settings. This second version addressed a few of the challenges and limitations of the original design in preparation for use at a clinic. This version offers many of the original systems features such as 3D volume PE and PAT scans capable of performing spectroscopy within the near infrared range (680 nm - 1000 nm) with the added value for potential to change transducers as the need arises for clinical imaging. The design changes to the system allow for maintenance time reduction of 48 hours turnaround time to 15 minutes. This thesis also introduces a portable cart-based system for patient imaging in a clinic. It enables imaging in a patient in a safe manner while allowing for a technician to both operate, monitor the exam, and characterize suspicious skin lesions in real time. The system also has potential use for a simple transducer substitution, as needed, depending on the clinician’s preference based on the characteristics of the transducer. This ability would open doors for tuned patient assessment and treatment monitoring.

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