Now showing items 21-40 of 15247

    • The Influence of Political Climate on Transborder Wildlife Conservation: A Case Study on the United States-Mexico Transborder Region

      Mars, Matthew; Hibbeler, Kari; Torres, Robert; Koprowski, John (The University of Arizona., 2021)
      Politics influences transborder conservation collaboration directly specific to wildlife projects. There is extensive research relating to transborder conservation as well as studies on the influence of governments and politics on conservation. However, research on the direct effects that government and/or politics have on transborder collaboration and conversation initiatives and interventions is scant. The need for understanding these influences and wildlife manager's' reactions to them is critical, as transborder collaboration is important to conserve and protect the wildlife that travels/inhabits the lands extending across border regions. The purpose of this study is twofold. The first goal is to understand the influence that politics has on transborder collaboration. The second goal is to determine how wildlife managers react to the political climate and its influence, as well as developing new insights to generate recommendations for future transborder collaborations and initiatives to occur effectively. This research focused directly on wildlife managers in the Arizona-Sonora region who conduct work specifically related on wildlife projects across the transborder region in direct collaboration with their neighboring country. I relied on political ecology theory as well as community-based collaboration as my conceptual framework to guide my study. The insights generated in this study provide future recommendations for transborder regions all across the globe.
    • Heat Management Alternatives in Deep Underground Mines as a Crucial Part of Mine Ventilation

      Momayez, Moe; Butani, Mohit; Muralidharan, Krishna; Waqas, Muhammad (The University of Arizona., 2021)
      The thermal transport properties of porous amorphous aluminosilicate structures are investigated using molecular dynamics simulations and finite element methods. This research aims to produce such aluminosilicate geofoam of desired thermal conductivity and use it as sprayable thermal insulation in deep mines or potentially in residential insulation applications. Aluminosilicates are naturally occurring minerals which have low thermal conductivity because of their high porosity. Since they are found in abundance in nature, they could be an economical alternative for the fabrication of thermal insulators used in the buildings and underground mines. The thermal and mechanical properties of the amorphous porous aluminosilicate structures (PAS) were studied during this research using computational and experimental methods. Molecular dynamics (MD) was used to characterize thermal properties and conductivity at the atomic level. Different Aluminum-Silicon ratios were studied in molecular dynamics to identify a suitable Al-Si ratio that would provide lowest possible thermal conductivity and high mechanical strength. The effect of density on thermal conductivity was also characterized. It was observed that thermal conductivity of the alumino silicate structure has a linear dependency on density. Also, for a particular given porosity, a larger distribution of smaller pores results in the aluminosilicate structure to have a lower thermal conductivity. This characteristic is related to the presence of more phonon scattering centers in highly porous systems thus causing a decrease in the mean free path of a phonon. The data obtained from the molecular dynamics simulations was used to physically fabricate the foams with similar densities in the laboratory and their associated thermal conductivity was experimentally measured. The molecular dynamics simulations and experimental data show a high degree of agreement with each other.The ultrasound non-destructive technique (NDT) was used to transmit wave energy to measure dynamic mechanical properties experimentally. This was performed for various different porosities of foams. The foam density was changed using different ratios of blowing agent and surfactant. The same was performed using the finite element method analysis in COMSOL Multiphysics platform for different sets of porosities. Acoustic and stress analysis was performed for different porosities to determine the P-wave and S-wave velocities and other elastic properties. A high-fidelity model of the foam was also generated using a micro-CT scan of the foam. Volume meshing was performed using Simpleware ScanIp software and was then transferred over to COMSOL to perform the modelling simulations. The data from different porosities obtained from these simulations agrees very well with the findings in the experimental analysis. The thermal conductivity values that have been obtained are seen to be a function of density of the material by transient plane source method. The mechanical properties have been characterized by Ultrasonic tests for macroscopic bulk specimens and techniques such as FEM at the Nanoscale and the results are hereby reported.
    • Improving Channel Equalization with Neural Network and Reinforcement Learning

      Bose, Tamal; Nguyen, Quyet van; Thamvichai, Ratchaneekorn; Ditzler, Gregory (The University of Arizona., 2021)
      In wireless communications, transmitted signals suffer from distortion caused by the channel. Equalization is used to mitigate such effects. However, a receiver needs to be adaptable to account for many types of channel effects, some of which may be nonlinear. Neural networks have been proven to be an effective method for wireless channel equalization due to their ability to learn and solve complex problems. In this thesis, two different techniques are presented to improve the use of Artificial Neural Networks (ANN) such that they can perform channel equalization more effectively. For the first technique, we present a system consist of multiple neural network (NN) equalizers, each trained on a specific channel such that a signal can still be equalized regardless of changes in channel conditions. In the first part of this experiment, we test the performance of this system of neural network equalizers on arbitrary channel models (i.e. squared, cubic, etc.). In the second part, we investigate the effectiveness of the system of neural network equalizers for different High Frequency (HF) channel conditions. The output of each NN equalizer in our proposed system is combined and optimized to select the best-equalized signal. Past research in the literature indicates that NN equalizers are vulnerable when channel conditions change because NN equalizers are trained on specific channel conditions. Based on simulation results, we show that our system can learn which NN equalizer is best suited for a particular channel as the channel varies over time. For the second technique to improve the channel equalization performance, we proposed using reinforcement learning to tune the hyperparameters of a neural network equalizer. When a neural network is created, before it can be deployed, a process called hyperparameter tuning is required for a neural network to perform at its best at a given application. For this work, we used an annealing epsilon greedy algorithm, which is a reinforcement learning technique to tune different attributes of a neural network equalizer. Reinforcement learning has been used to tune neural networks for other applications, but to the best of our knowledge, it has not been done for neural network equalizers. HF is also the assumed channel for this part of our work, and we investigate the effectiveness of using the annealing epsilon greedy algorithm to tune a neural network equalizer by comparing its equalization performance with a fixed neural network equalizer (i.e. by fixed we mean that the neural network can learn the weights but cannot change the value of its hyper-parameters). From the results obtained, at three distinct HF channel conditions used for this work, the neural network equalizer tuned with the epsilon greedy algorithm can outperform a fixed neural network equalizer.
    • Extended Finite-Difference Time-Domain Method for Dynamics in Ferrite Material

      Brio, Moysey; Denny, Bud; Sanchez-Vizuet, Tonatiuh; Imbert-Gerard, Lise-Marie (The University of Arizona., 2021)
      We present a broad overview of Maxwell's equations and the standard finite difference time domain (FDTD) method. Furthermore, we develop and analyze a FDTD scheme for Maxwell's equations in ferrite material. We present basic results about Maxwell's equations, the FDTD method, and the governing equations for electromagnetic phenomenon in ferrite material. We insert the Landau-Lifshitz equation (which models the dynamics of the magnetization vector M in ferrite material) into the standard FDTD method. We place the M ield at cell centers and derive an explicit update for its field components. We show the scheme is stable for certain ferrite material parameters by using Von Neumann and eigenvalue stability analysis. Finally, we show our method, due to boundary conditions, loses the 2nd order convergence enjoyed by the standard FDTD method.
    • Direct Numerical Simulations of Hypersonic Boundary Layer Transition on Blunt Cones

      Fasel, Hermann; Hartman, Andrew; Little, Jesse; Craig, Alex (The University of Arizona., 2021)
      Direct Numerical Simulations (DNS) were carried out to investigate laminar-turbulent transition for a straight cone (7 degree half-angle) for four different cases with varying nose radii and flow conditions at Mach 6 and zero angle of attack. First a conventional Linear Stability Theory (LST) solver was used in order to determine the critical Reynolds number for amplification of second mode disturbances for each of the cases. Next, (linear) stability calculations were carried out by employing a high-order Navier-Stokes solver and using very small disturbance amplitudes inorder to capture the linear disturbance development. Contrary to standard Linear Stability Theory results, these investigations revealed a strong ``linear'' instability in the entropy layer region for a very short downstream distance for oblique disturbance waves with spatial growth rates far exceeding those of second mode disturbances. This linear instability behavior was not captured with conventional LST and/or the Parabolized Stability Equations (PSE). Secondly, nonlinear breakdown simulations were performed using high-fidelity DNS for three different cases. The DNS results showed that linearly unstable oblique disturbance waves, when excited with large enough amplitudes, lead to a rapid breakdown and complete laminar-turbulent transition in the entropy layer just upstream of the second-mode instability region.
    • The Role of GABA Shunt and Hepatic GABA Transporters on Hyperinsulinemia and Insulin Resistance

      Renquist, Benjamin J.; Ghimire, Susma; Stern, Jennifer H.; Duca, Frank A. (The University of Arizona., 2021)
      Hepatic lipid accumulation, a hallmark of type 2 diabetes (T2D), increases hepatic gamma-aminobutyric acid (GABA) production through the GABA shunt and release by electrogenic GABA transporters. Inhibition of either GABA production or GABA release limits obesity-associated hyperinsulinemia and insulin resistance in obese mice. In turn, we assessed the role of GABA producing enzymes within the GABA shunt and GABA transporters (TAUT, CRT, BGT1 and GAT2) in development of hyperinsulinemia and insulin resistance in diet induced obese mice. We established that liver slice GABA release was increased in obesity, and positively associated with serum insulin and insulin tolerance test area under the curve (ITT AUC). To understand the regulation of GABA production we showed that media GABA was positively associated with Aldh5a1 mRNA and negatively associated with Abat mRNA. In turn, Aldh5a1 mRNA expression was positively associated with 4h fasted insulin, HOMA-IR, and ITT AUC, while Abat mRNA was negatively associated with 4h fasted insulin, and ITT AUC. Because we have previously shown that SLC6A6 was associated with worsened insulin resistance and SLC6A12 was associated with improved insulin sensitivity in humans, we created adeno associated virus (AAVs) to induce hepatic overexpression of hSLC6A6 and hSLC6A12 in mice. Surprisingly, after 3 weeks of HFD exposure, mice expressing hSLC6A6 had improved insulin sensitivity as assessed by ITT or HOMA-IR. Still despite the improved insulin sensitivity, both hSLC6A6 and hSLC6A12 expression worsened glucose tolerance in 3-week high fat diet fed mice. Together the data presented here supports a role for the GABA shunt and electrogenic GABA transporters in regulating glucose homeostasis.
    • Data Science for Environmental Justice: Community-Based Rainwater Harvesting and Environmental Monitoring in Arizona

      Ramírez-Andreotta, Mónica D.; Palawat, Kunal; Root, Robert; Buxner, Sanlyn R. (The University of Arizona., 2021)
      As climate change exacerbates water stress already experienced by 2.3 billion people worldwide, rainwater harvesting for household gardening becomes an increasingly common practice. However, the quality of harvested rainwater is not well studied, and the human health risks associated with its use are unknown. There is currently no United States federal standard to assess harvested rainwater. This thesis discusses Project Harvest, a co-created community science project studying the quality of harvested rainwater, primarily used for garden irrigation, in four environmental justice communities in Arizona, USA. Participants collected 577 rooftop harvested rainwater samples from 2017-2020, where arsenic (As) concentrations ranged from 0.108 to 120 ug L-1 and lead (Pb) concentrations ranged from 0.013 to 350 ug L-1 with the highest concentrations in the community of Hayden/Winkelman > Tucson > Globe/Miami > Dewey-Humboldt. Rooftop harvested rainwater data were analyzed with linear mixed models showing summer concentrations of As and Pb were significantly higher than winter; and, contamination was significantly higher closer extractive industry sites in three of the four study communities (ASARCO Copper Smelter in Hayden/Winkelman, Davis-Monthan United States Air Force Base in Tucson, and Freeport McMoRan Copper and Gold Mine in Globe/Miami). Additionally, rainwater harvesting infrastructure such as roof material, presence of cistern screen, and cistern first flush were not significant when controlling for relevant spatiotemporal variables. These results indicate that As and Pb concentrations vary seasonally and by proximity to industrial activity, not by individual decision making about homes. In general, individuals are not responsible for environmental contamination, rather governments, corporations, and other external powers are responsible. Future work will integrate harvested rainwater, residential soil, and garden plant data to better understand sociobiophysical drivers of environmental change. Further research should explicitly address the role of industry and racial capitalism in environmental injustice and integrate transdisciplinary datasets to address community-driven questions.
    • Spain and "Spanishness" in Tucson: 1880-1900

      Garcia, Juan R.; Angiulo, Patrick; Perez, Erika; Vetter, Jeremy (The University of Arizona., 2021)
      Two contrasting visions of Spain and its colonial legacy in Sonora (andArizona) existed in Tucson’s newspapers at the end of the nineteenth century. One vision, present in the town’s English-language newspapers, portrayed Latin American territories once under the control of Spain’s colonial empire as abandoned and ready for Anglo-American business interests to claim and profit from. In this conception, Spain was typically depicted as either an archaic, cruel master of Latin America or as the original European pioneer of regions that would ultimately be dominated by Anglo-Americans. In contrast, Tucson’s Spanish-language newspaper, El Fronterizo, insisted that Spain’s empire was never abandoned and that Mexico’s autonomy rested on both the repudiation of Spanish domination and legal continuity from the viceregal era. While depictions of Spain as a colonial power were often negative in El Fronterizo, the paper also emphasized the potential for Spain, Mexico, and even the United States to work together as equal partners in liberal capitalism. This vision, however, was incompatible with the Anglo-American image of Sonora’s abandoned Spanish past, an image that proved to be more influential as Tucson increasingly incorporated into U.S. economies and cultures following the arrival of the Southern Pacific Railroad in 1880. Nevertheless, El Fronterizo’s vision of Spain persisted until at least the end of the nineteenth century, giving tucsonenses access to a narrative with the potential to contest both U.S. and Spanish domination.
    • Pediatric Germline Predispositions to Myelodisplastic Syndrome, Expert Guidance for the Initial Evaluation and Management of SAMD9 and SAMD9L Variants, and the Importance of Database Development for these Rare Syndromes

      Hammer, Ronald; Wlodarski, Marcin; Nelson, Catherine; Garcia-Filion, Pamela; Williams, James (The University of Arizona., 2021)
      Bone marrow failure and hematologic malignancy is rare within the pediatric population. Germline mutations within this population were initially thought to be rare, but we are finding that these malignancies are more likely to have germline predispositions than initially thought. SAMD9/SAMD9L activating (gain or change of function) germline heterozygous mutations are a severe rare blood disorder with malignant potential in need of greater understanding and acute guidelines for diagnosis and therapy. In November 2019, the St. Jude Children’s Research Hospital sponsored the first international symposium on SAMD9/SAMD9L mutations. Forty internationally recognized experts met with the goal to develop a consensus on the diagnosis, monitoring, and management of individuals diagnosed with SAMD9/SAMD9L associated syndromes and carriers within affected families. The group mission was to improve accuracy of diagnosis and the timely detection of complications. A manuscript was then created, using the modified Delphi approach, to reflect the group’s recommendations for the initial evaluation and management of patients suspected to have SAMD9/SAMD9L variants. This manuscript is the first step to improving care for patients with SAMD9/SAMD9L variants. Future research involves a patient registry/natural history prospective study to establish the data required to support the treatment recommendations which are controversial. Database development is an essential part of ensuring these registries are effective at collecting the necessary data. Rare disease registries are essential to comprehensively increase knowledge about disease characteristics, the natural course of these diseases, and assess the long-term outcomes of the patients affected by them.
    • A Retrospective Analysis of Historical Reservoir Operations in Conus

      Condon, Laura; Steyaert, Jennie C.; Troch, Peter; Meixner, Thomas (The University of Arizona., 2021)
      In the contiguous United States (CONUS), there are over 52,000 reservoirs ranging from 0.5 to 243 meters high. Collectively they hold 600,000 MCM of water. These structures have dramatically affected the river dynamics of every major watershed in the country. The operations of these structures depend on a variety of climatic, anthropogenic and reservoir drivers, however, the lack of a comprehensive national dataset makes interpolation of the importance of these drivers hard to analyze. To start to address this gap we have assembled a national dataset of historical reservoir operations called ResOpsUS. Here we present the dataset, titled ResOpsUS, and evaluate static reservoir properties against the existing global reservoir database, GRanD. We then evaluate trends in operations by region and reservoir purpose. ResOpsUS contains reservoir inflow, outflow, and storage values for 679 reservoirs across CONUS. These reservoirs cover 55% of the total storage in large (greater than 1 MCM) reservoirs across the US. We show that observations agree well with the static reservoir properties reported in Grand; however, there are some systematic biases. Specifically, maximum storage capacities align with the maximum storage of irrigation reservoirs, but not necessarily flood control reservoirs, while releases of flood control reservoirs most closely align with naturalized flows. Analysis of transient operations highlighted regional and purpose-based differences in strength of the relationship between precipitation and storage and reservoir releases. Most specifically, it demonstrated that regions with large correlations between inflow and precipitation are more likely to have low correlations between cumulative storage and releases. These regional trends are most closely associated with the main use of reservoirs, however, some areas, specifically Texas, see correlations that are more nuanced due to multipurposed reservoirs.
    • Food Without Fire: Nutrition Impacts from a Solar Stove Field Experiment

      Michler, Jeffrey D.; McCann, Laura Elizabeth; Josephson, Anna L.; Bakkensen, Laura A. (The University of Arizona., 2021)
      Population pressure is speeding the rate of deforestation in Sub-Saharan Africa, raising the monetary and opportunity costs of meal preparation. Many people rely on firewood or charcoal to prepare food. Using a field experiment in Western Zambia, we investigate the impact of solar cook stoves on compositional changes in diet when constraints to cooking nutritionally diverse foods (e.g., legumes) and the cost of meal preparation are removed. We find no impact on diet for those households assigned to the solar stove treatment. We do see a significant result for the average number of dishes per household meal. These results offer valuable insights into program development for the provision of solar stoves to reduce the cost of meal preparation.
    • The Representational Format of Moral Concepts for Situated-Action

      Aronowitz, Sara; Dooling, Uphaar; Jansen, Peter; Theriault, Jordan (The University of Arizona., 2021)
      Moral concepts serve central roles in facilitating our everyday moral though and behavior. Despite their importance, few attempts have been made to provide or characterize a satisfactory psychological theory of moral concepts that can accommodate their representational features and explain their function within our everyday moral experiences. In this thesis, I argue traditional psychological theories of concepts that posit invariant representational formats cannot provide a satisfactory theory of moral concepts while accommodating their motivational roles in the selection of situationally appropriate and time-sensitive action. The evaluative content and motivational force of a tokened moral concept varies across each instance and is highly situated to the agent’s present environment, cognitive tasks, constraints of the situation, etc. Invariant representational formats of concepts are unable to accommodate for the variable conceptual content and are unfit to ground a theory of moral concepts while maintaining their central roles within facilitating our moral cognitive capacities. Instead, I argue, any viable psychological theory of moral concepts must posit a flexible and context-sensitive representational format to meet the variation present during instances of moral experience.
    • Sex-Dependent Differences in Amyloid-β Accumulation in a Mouse Model of Alzheimer's Disease

      Pires, Paulo W.; Gee, Michael; Banek, Christopher T.; Chignalia, Andreia Z.; Konhilas, John P. (The University of Arizona., 2021)
      Alzheimer’s disease (AD) is a common cause of dementia and has a higher incidence in females. One of the pathological hallmarks of AD is the abnormal accumulation of amyloid-β (Aβ) plaques in the brain, which ultimately results in cognitive decline. It has been hypothesized that the accumulation of Aβ is facilitated by a modified form of Aβ, referred to as pyroglutamate Aβ (Aβ-pE3), which forms the core of Aβ plaques. Additionally, most AD patients display cerebral amyloid angiopathy (CAA), where Aβ accumulates around vessels of the brain. CAA can lead to a reduction in capillary number referred to as capillary rarefaction. This could reduce blood flow to the brain and contribute to the AD-associated cognitive decline. Whether the underlying mechanisms behind the higher incidence of AD in females involve sex differences in Aβ, Aβ-pE3, CAA, or capillary rarefication is not clear. Thus, we used histological techniques to characterize the 5x-FAD mouse model of Aβ accumulation independently of aging to determine if differences in Aβ or Aβ-pE3 accumulation, CAA, and capillary rarefication vary by sex in AD. At 3 months of age, there was no sex difference in Aβ plaque density and coverage in the cortex and hippocampus of 5x-FAD mice. However, female 5x-FAD mice displayed a significantly higher Aβ-pE3 plaque density, coverage, and percentage of Aβ-pE3-cored plaques in those same regions. No sex differences in Aβ and Aβ-pE3 plaque density was observed in 1- and 2-month-old 5x-FAD mice. No differences were observed in blood vessel volume or capillary number when comparing 3-month-old 5xFAD male and female mice to their wild-type littermates. Additionally, CAA was present on the pial vessels and, to a lesser extent, parenchymal vessels of 3-month-old 5x-FAD mice without sex differences. Thus, 3- month-old 5x-FAD mice display sex differences in Aβ-pE3, but not overall Aβ accumulation, CAA, or capillary rarefaction. This sex difference in Aβ-pE3 seemed to not be present in 1- and 2-month-old 5xFAD mice. Although 3-month-old female 5x-FAD mice had an elevated Aβ-pE3 load, no capillary rarefication and parenchymal CAA was observed. This suggests that the microvasculature of these mice is unaffected, at least at the age studied. Future studies are aimed at assessing possible sex differences in the function of these vessels.
    • Impacts of an Adversary Attacking Filter-Based Feature Selection Algorithms

      Ditzler, Gregory; Gupta, Srishti; Potter, Kelly; Hariri, Salim (The University of Arizona., 2021)
      Applying complex mathematical calculations to big data, extracting insightful information, adapting new data independently, and providing scalable solutions have attracted various industries including healthcare, financial, computer-vision, cyber-security, automation, etc. The ubiquitous use of Machine Learning (ML) has become almost ordinary. ML has not only lured businesses but has also interested the archenemies of society. Due to the multi-faceted applications of ML, practicing ML with malicious intent can cause severe deleterious effects on individuals, society, organizations, and the environment. With the recent spread of awareness for the ethical use of ML, we are centuries away from its noble only applications. Adversarial Machine Learning (AML) is a branch of ML that aims to make ML models robust and secure against adversaries. Since most of the feature selection and ML algorithms in a data science pipeline were developed in an adversary-unaware environment, studies have shown that these algorithms are vulnerable to attacks and can be easily compromised in the presence of an intelligent adversary. In the last decade, a tremendous amount of work has been done to develop carefully crafted attacks that can subvert the predictions of state-of-the-art ML models along with their suitable countermeasures. However, majority of these works are limited to the robustness of classifiers and their secure predictions. Unfortunately, with an intent to wreck an ML model, the adversary can seed an attack anywhere in a data science pipeline. Adversarial Feature Selection (AFS) is a novel sub-field of AML that intends to make feature selection algorithms guarded against adversaries. The study of AFS is ever more important due to the nature of damage an attack can do at the feature selection stage. For example, if an intelligently crafted adversarial input perturbation has been planted in the raw data right before the feature selection, a feature selector ends up selecting wrong features for training and testing data which may lead to bad learning of a classifier. The faulty classifier may even predict apparently well on testing data giving a false sense of legitimacy. Therefore, it is equally important to protect feature selectors as classifiers. Due to the novelty of the field, we do not have many targeted attacks for feature selection algorithms. In most literature, attacks studied in AML only refers to classifier attacks to the point it is used interchangeably. In this work, we demarcate classifier attacks from feature selection attacks, both being a sub-field of AML. The main focus of this thesis is to study the transferability of existing feature selection and classifier attacks on filter feature selection algorithms. The motivation of this study is to understand the behavior of filter algorithms in an adversary-aware environment even when the attacks are not directed towards the filter methods. Filter algorithms are studied because of their widespread usage due to their computationally inexpensive and classifier-independent characteristics. First, we show that feature selection attack designed for LASSO is transferable to filter algorithms. Then, we expand the study and show that classifier attacks are also transferable to filter feature selection algorithms, even when these attacks are not originally crafted for feature selection stage. The degree of impact varied among different feature selectors.
    • The Effect of Lignin Content on the Growth and Yield of Two Specialty Mushroom Species: Pleurotus ostreatus and Hericium erinaceus

      Pryor, Barry M.; Bonner, Charlotte Rose Melville; Kacira, Murat; Orbach, Marc (The University of Arizona., 2021)
      White-rot fungi can convert inedible agricultural waste into highly nutritious, gourmet mushrooms. These fungi have a plethora of enzymes allowing them to degrade some of the most recalcitrant organic molecules: lignin, hemicellulose, and cellulose. However, the mechanisms by which fungi accomplish this under mushroom cultivation conditions are poorly understood. This study examines the effect of various lignin levels on the biological efficiency (BE) and substrate degradation patterns for two specialty mushroom species, P. ostreatus and H. erinaceus in a controlled environment. The goal was to better understand the nutritional requirements of the fungi during different growth stages and the impact of lignin on fungal growth. This work attempts to improve the efficient use of agricultural wastes as growing media for specialty mushrooms and was carried out in a series of three experiments. The first two experiments cultivated P. ostreatus on oak- and wheat-based substrates with increasing lignin contents (5-28%) while attempting to hold the cellulose, hemicellulose, and nitrogen percentages constant. The third experiment grew P. ostreatus and H. erinaceus on oak, wheat, and coco coir each supplemented with 50% soybean hulls. For all experiments, the effect of substrate was quantified by measuring the BE as well as the cell wall components, lignin and cellulose, measured before inoculation, after spawn run, and after harvest. Results from the first two experiments cultivating P. ostreatus revealed that increasing substrate lignin content in oak-based substrates resulted in a significant decrease in BE, but no significant effect of lignin content on BE was observed for wheat-based substrates, although the same trend was evident. Additionally, the initial substrate lignin content had a significant effect on lignin consumption for both oak- and wheat-based substrates but this effect was only apparent for substrates with high initial lignin contents. For substrates with low lignin content, very little lignin was consumed. Interestingly, the acid detergent fiber (ADF) measurement used to quantify cellulose gradually increased over time which was likely due to the ADF detecting both cellulose and chitin, therefore as more plant cellulose was converted to fungal chitin, ADF increased. In experiments comparing the response to substrate lignin by P. ostreatus and H. erinaceus, there was no significant effect of lignin content on BE for both species and similarly, the most lignin was consumed in the substrates with the greatest initial lignin contents for both species. The trend of increasing ADF over time was observed for P. ostreatus, but in contrast, not for H. erinaceus. This observation is likely from the low BEs with H. erinaceus, thus less plant cellulose converted to fungal chitin.
    • Reclaiming a Fractured Flow: Identifying Policy Barriers and Opportunities for Green Infrastructure in Ambos Nogales

      Banister, Jeffrey; Schwartz, Patricia; Zuniga-Teran, Adriana; Wilder, Margaret (The University of Arizona., 2021)
      With the global explosion of urbanization, flooding due to expanding impervious surfacescreates public health hazards, damages and disrupts economies in regions undergoing rapid development. Conventional hard-path infrastructures and reactive recovery strategies are inadequate for addressing stormwater management issues in the long term, and oftentimes they fail to consider social and environmental disparities among city residents or make them worse. Mitigating urban hazards and the compounding threats of climate change requires bolstering community capacity to adapt to and recover from disasters before they occur, in ways that are integrated into urban planning and political processes. Green Infrastructure (GI)—the use of natural, permeable materials and strategies to manage stormwater through in situ infiltration— has gained traction for its potential to mitigate negative impacts and provide a wide array of environmental and social benefits. However, there remain significant challenges to GI adoption at the watershed level—the scale at which these techniques are most effective—particularly across political boundaries. A network of actors in the sister cities of Ambos Nogales, bisected by the contentious Mexico-United States border, are pursuing GI to deal with severe flooding and water contamination problems exacerbated during monsoon storms that overwhelm current binational conveyance infrastructures. However, complex structural and political limitations have stunted recent efforts at crossboundary collaboration and planning. This thesis examines de jure and de facto barriers to the adoption of a GI design as set forth by the North American Development Bank’s Border 2020 Program. It first sketches the political-economic and historical dynamics underlying mismatched environmental regulation and planning policies between the two cities, examining shortcomings of a policy-based adaptation approach. It then utilizes extensive documentary and qualitative research, including key informant interviews, a survey and focus group with local stakeholders, to identify existing and potential opportunities for GI advancement across the divided Nogales landscape. The report describes potential project and incentive-based interventions and presents grassroots and informal networks as key strengths in a push towards GI. This study and resulting data-dissemination and GI-implementation efforts provide novel insights and support for engaged local actors and have implications for similar transboundary cities. Its findings advance understudied aspects within multiple literatures—urban political ecology, environmental justice, and critiques of racial capitalism—by examining their nexus in the context of a bordered landscape. They contribute to broader discussions around GI and transboundary water management, including questions about the potential benefits and/or pitfalls of GI and the functionality of decision-making networks across political-physical boundaries. Supporting place-based interventions through the input of stakeholders often left out of the conversation, our findings bolster the exchange of knowledge and development of capacities necessary to address shared challenges in the region.
    • The National Idea in Russian Literature and Political Discourse

      Leafgren, John R.; Willerton, John P.; Berlin, Mikhail; Klimanova, Liudmila (The University of Arizona., 2021)
      According to Galina Krinitskaya, most acutely, the Russian national idea "manifested itself inRussian public thought and literature, through which the historical forecast of the future world order, and the role of Russia in this process, was revealed."1 The 1917 Revolution and the dissolution of the Soviet Union in 1991 marked periods of radical change during which the existing national identity, as well as the national idea that had ramified from it, were rejected by the political forces which rose to the top. Today, when the country is well overdue for a clearly defined 21st– century image of itself and its citizenry, the Russian society suddenly finds itself in an ideological impasse, struggling to agree on a unifying vision. This research theorizes that Vladimir Putin, who has been the head of the Russian state for over two decades, is the likely and the most influential figure in modern Russian history who can articulate and implement the new Russian national idea. This research aims to examine the Russian national idea as an object of study in Russian literature and carry out a comparative analysis between works of the 19th–20th centuries against the ideas set forth by the head of the state between 1999 and 2021.The analysis of Vladimir Putin's speeches on the subject permits tracing his views' evolution and measures them against their alternatives in literature and academic discourse. The definition of the national idea presented by Russian literature, in comparison with its interpretation in the speeches of the President of the Russian Federation, made it possible to conclude the following: despite being "distant" from each other by almost two centuries, the social and philosophical ideas have a common ground. The President's definition of the national idea in many ways "harmonizes" with the ideas voiced in Russian literature and the comparative analysis of these definitions allows one to draw these very conclusions. While literary authors consider national idea through the use of various artistic techniques, voicing it through the statements and thoughts of their heroes, the statements of the head of state presuppose a public understanding of his message regarding the essence of the national idea, hence the brevity, capacity, and clarity of its definition in the speech of the President. ______________________________________________________________________________ 1) Galina Krinitskaya, Natsional'naia ideia Rossii: Istoriia i prognozy: Monografiia (Tomsk: Tomskiigosudarstvennyi universitet, 2016), 6.
    • A Multiplexed Hybrid Velocimeter

      Kost, Alan R.; Pena, Michael Thomas; Kieu, Khanh; Djordjevic, Ivan (The University of Arizona., 2021)
      Optical velocimetry systems play a crucial role in studying the dynamic behavior of materials under extreme conditions. Two prominent systems used at the Nevada National Security Site are the velocity interferometer system for any reflector (VISAR) and the photon Doppler velocimeter (PDV) system. Their ability to accurately measure surface motion ranging from 0 to >20km/s without interacting with material flow enables experimenters to construct thermodynamic equations of state for materials of interest. A number of modifications to VISAR and PDV have taken place over the past five decades, leading to improved performance, increased recording capacity, and a reduction in operational burden. Prior efforts to develop a hybrid velocimeter combining the advantages of both PDV and VISAR into a single diagnostic did not take into account progress in PDV technology or new optical components that had not been developed. This thesis describes the design and implementation of a multiplexed hybrid velocimeter (MHV) based on time-multiplexing techniques, an optical hybrid, and polarization-maintaining fiber and components. Data from experiments, compared with current velocity systems, serve to demonstrate the hybrid's performance.
    • Intrauterine Fetal Growth Restriction and Sexually Dimorphic Programming of Adipocytes

      Goyal, Ravi; Blomberg, John; Craig, Zelieann; Dhar, Arun; Limesand, Sean (The University of Arizona., 2021)
      Worldwide, fetal growth restriction (FGR) affects 7 to 10% of pregnancies, or roughly 20.5 million infants each year. FGR not only increases neonatal mortality and morbidity but also the risk of obesity in later life. Currently, the molecular mechanisms by which FGR "programs" an obese phenotype are not well understood. Of note, studies demonstrate that FGR females are more prone to obesity as compared to males; however, the molecular mechanisms that lead to FGR are not known. Thus, I hypothesized that FGR causes sexually dimorphic programming of adipocytes by differentially regulating preadipocyte gene pathways. To test the hypothesis, we induced FGR using a sheep model subject to increased ambient hyperthermia. We collected perirenal adipose tissue from male and female near-term FGR and normal weight fetal lambs (N=4 in each group, 16 total). Second-generation RNA sequencing (RNAseq) was conducted on RNA isolated from adipose tissue to examine the differences in gene networks and pathways. For phenotypic results, averages across the four samples for each group were obtained. The current studies demonstrated that male FGR (MFGR) has a significantly greater mean fat globule area than normal-weight male fetus and a greater fat globule area than all other groups. In contrast, there was no significant difference in average fat globule area between female FGR (FFGR) and normal-weight female fetus. A four-way RNAseq comparison demonstrated significant differences in gene expression between FGR and control groups and between sexes. In conclusion, we observed a sexually dimorphic phenotype and gene pathways in response to FGR.
    • The Comparison of Leadership Styles and Satisfaction of Student Athletes

      Torres, Robert M.; White, Bryce; Mars, Matthew M.; Molina, Quintin F. (The University of Arizona., 2021)
      This study investigates the relationship of leadership styles displayed by head coaches of colligate athletics and the ascendent satisfaction of the student-athlete experience. Electronic questionnaires were sent to 431 active student athletes from an American Division 1 University, 40 athletes completed the questionnaire. Student athletes were requested to respond to a modified version of the Athlete Satisfaction Questionnaire (ASQ). This instrument accurately collected data on athletes’ current satisfaction regarding the overall satisfaction of the perceived student-athlete experience. Participants were then asked what leadership style best represented their head coach (Democratic, Autocratic, Laissez-faire). Participating student athletes from the American D1 university completed questionnaires identifying democratic leadership as the predominant leadership style displayed by head coaches, followed by laissez-faire, and autocratic. Further, the democratic leadership style yielded a higher amount of athlete satisfaction across all 11 measured factors when compared to the other leadership styles.