RSS 1.0UA Graduate and Undergraduate Research
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The graduate and undergraduate research collections share, archive and preserve research from University of Arizona students. Collections include honors theses, master's theses, and dissertations, in addition to capstone and other specialized research and presentation topics.
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ProgressionWhat 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 SimulantPlant-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 ArizonaThe 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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The Trumpet in Italian and British Music of the Baroque Era: A Musical-Rhetorical Point of ViewThis dissertation aims to analyze the trumpet music of the Baroque era according tothe musical-rhetorical theory of the period. I will examine the social context in which both the trumpet compositions and the publication of the treatises on musical-rhetorical relationships could flourish. I will then introduce musical-rhetorical theories and provide an analysis of trumpet music.
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The Development, Implementation, and Evaluation of Culturally Tailored Cancer Prevention Presentations in an Urban American Indian and Alaska Native CommunityUrban American Indian and Alaska Natives individuals, communities, and populations have unique cancer health outcomes, as the incidence of certain detectable cancers is higher for this group. The project aimed to educate and promote cancer screening among the urban American Indian and Alaska Native community in Tucson, AZ, by creating culturally tailored cancer prevention presentations. Methods: A literature review was conducted to identify cultural characteristics that were included in the creation of the presentations. Presentations were modeled after the Circle of Life curriculum. Literature review findings and expert input were used in the development of the presentations. An evaluation survey was administered to measure presentation effectiveness on participant’s knowledge and agreeability to engage in cancer prevention behaviors (n=76) and Talking Circles (n=4) were conducted to understand participants’ (n=35) perceptions and gather feedback for improvement. Results: The literature review identified eight cultural characteristics from previous American Indian and Alaska Native community recommendations for cancer programming (e.g., Native representation, family importance, storytelling, mixed multimedia delivery, Traditional healing and Traditional ways of knowing, and clinical recommendations). The evaluation survey indicated that most of the respondents ‘strongly agree’ or ‘agree’ that the presentations increased knowledge and encouraged participants to engage in cancer prevention behaviors. The Talking Circles revealed that more information on Traditional tobacco and Traditional foods is needed and incorporating an elderly cancer survivor to share their cancer journey would encourage cancer screening; providers should talk more about cancer screening with their patients; and fear and hesitancy and transportation were identified as barriers to cancer prevention care. Conclusion: The findings show that culturally tailored cancer prevention presentations increase knowledge and encourage cancer prevention behaviors. More information on Traditional tobacco and Traditional foods should be added to the presentation for improvement. Addressing the feelings of fear and hesitancy among urban American Indian and Alaska Native individuals will further promote cancer screening practices.
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Speaker Creation in Indigenous CommunitiesThis dissertation is written for people that want to see Indigenous North American languages add new speakers to their speaking communities. It is my hope that community practitioner-educators as well as academic linguists will gain insight into speaker creation as I have facilitated it in my career as a language worker. This dissertation aims to link academia and practical implementation to collaboratively address the distinction between language reclamation and language revitalization, avenues of collaboration between indigenous communities and linguists, and the roles and responsibilities of people working to revitalize North American Indigenous languages with few remaining first language speakers. The discourse of this dissertation is intended to be accessible to both seasoned linguists, budding linguists, and non-linguists alike. The concepts are presented in a manner that respects the cultural nuances and lived experiences of Indigenous communities and prioritizes my personal experiences and perceptions of language work. Also, the privileging of community-centric examples is paramount in this work as it not only makes the content of this dissertation accessible but also relatable to people working in language revitalization of North American Indigenous languages with few remaining first language speakers. While an academic audience may appreciate theoretical frameworks and comprehensive literature reviews, the community audience will find value in practical examples, success stories, and step-by-step guides. The discourse of this dissertation is intended to resonate with both audiences, ensuring that the research remains academically rigorous while remaining directly applicable to those actively engaged in language revitalization. This dissertation explores the methodology of and notion of speaker creation in the context of Indigenous language revitalization by detailing the use of whole language immersion for accelerated language acquisition. Chapter One takes an in-depth look at the nature of the problem and the need for a meta-analysis and synthesis of the existing literature and my lived experience. Chapter Two is a literature review that summarizes the published work on successful speaker creation methods used in Indigenous communities and second language acquisition experiments. The literature review is written to give primacy to my lived experiences of creating speakers of the under-resourced, highly endangered Indigenous language. In Chapter Three, I discuss the methodologies often employed by Indigenous language workers who most times come from the backgrounds of linguistics, American Indian Studies, second language acquisition and teaching, and community-level revitalization. In Chapter Four, I introduce the notion of speaker creation in Indigenous North American communities. That is the process of bringing learners from zero heritage language speaking ability to being conversational enough to understand and express themselves to fluent first language speakers. Included in this work is a walk-through of a proposed template curriculum to be used by language workers wishing to gain accelerated speaking ability in any North American Indigenous language with few remaining first language speakers. In Chapter Five, I discuss the intersection of indigeneity, linguistics, and second language acquisition theory in the context of language acquisition and language education programming. I provide a discussion on the nuts and bolts of language assessment and policy implications for tribal programs that want to facilitate conversational speaking ability in their community. I follow up with concluding thoughts and recommendations for future research in the subject area of speaker creation in North American Indigenous language communities.
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Cysteine and Methionine Deprivation Sensitizes Cells to N-Acetyl CysteineAmino acid metabolism is crucial for cells to maintain cell growth, facilitate protein production, and also enables cell signaling. Two amino acids of particular importance are the sulfur containing amino acids, cysteine and methionine. Cysteine is essential to cells as it is the limiting substrate for glutathione (GSH), the primary antioxidant in cells. Cysteine can also be oxidized in proteins and can dictate cell signaling pathways. Methionine is crucial as the starting amino acid in all proteins and is also essential for maintaining adequate cysteine levels through the transsulfuration pathway (TSP). The TSP is governed by two enzymes cystathionine gamma lyase (CTH) and cystathionine beta synthase (CBS) which catalyze the conversion of methionine to cysteine. CTH and CBS can also generate hydrogen sulfide (H2S) utilizing homocysteine and cysteine as substrates. H2S has recently gained attention for its dichotomous role within cells. At low concentrations, H2S can coordinate cell signaling through protein sulfhydration, can stimulate oxidative phosphorylation through donating electrons, and can act as an antioxidant to help cells cope with oxidative stress. At high concentrations, H2S becomes toxic through inhibition of the electron transport chain leading to cell death. Therefore, cells must buffer H2S levels to ensure the toxic threshold is not surpassed. In this dissertation, we found that deprivation of cysteine and methionine leads to a decrease in cell growth and activation of the Integrated Stress Response (ISR) pathway. In addition, cysteine and methionine deprivation leads to an increase in H2S levels, though the levels remain nontoxic. However, the addition of an antioxidant, N-Acetyl Cysteine (NAC) leads to a more pronounced increase in H2S levels and leads to toxicity through an increase of reactive oxygen species (ROS). We show that inhibition of the H2S generating enzyme, cystathionine gamma lyase (CTH), decreases H2S levels and restores cell viability in NAC and cysteine/methionine deprived cells.
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Effects of Posterior Caudatoputamen Indirect Pathway Activity on Auditory Cortical Activation in Female RatsHallucinations are a part of a complex and disabling psychiatric disorder of schizophrenia. Strong associations with dysregulated dopamine signaling, especially via dopamine D2 receptors, have been made with these symptoms. Despite a huge amount of progress in determining how dopamine works, a mystery still lingers in the mechanisms underlying auditory hallucinations, one of the main symptoms of schizophrenia. Here we investigated the relation of dopamine, sex differences, hormonal states, and activation of cells in female rats caudatoputamen (CPu) and the auditory cortex (Au1). This research looks at the effects of dopamine on Fos expression as a marker of neuronal activity using a combination of intracranial dopamine infusions, immunohistochemistry and immunofluorescence. Dopamine infusion in the auditory striatum leads to increase in Fos expression in the Au1, and the greatest activation occurs during the proestrus phase of the estrous cycle. Elevated levels of both estrogen and progesterone during proestrus are clearly important in enhancing dopaminergic response, suggesting the crucial participation of gonadal hormones in modulating neuronal activation. In addition, a comparison with male subjects reveals significant sex based differences for dopaminergic signaling with female subjects being more sensitive. The effects of haloperidol, a selective D2 receptor antagonist, on dopamine induced auditory cortical activation are also explored by the dissertation. The CPu is densely comprised of D2 receptors, and therefore it is likely that D2 receptors in the CPu play a key role in this linkage between dopamine dysregulation and Au1 activity. Consistent with this idea, haloperidol significantly attenuated Fos expression in the Au1. This attenuation parallels the therapeutic effects of antipsychotic medications reinforcing the significance of this model in studying schizophrenia like symptoms. Taken together, these findings provide compelling evidence for sex, hormonal state, and dopaminergic signaling interactions with modulating auditory cortical activity. These insights also give us an understanding to the neural circuitry underlying auditory hallucinations, and the mechanisms by which antipsychotics mitigate auditory hallucinations. Further, this work also emphasizes the importance of incorporating sex and hormonal factors into preclinical study designs since these variables may define critical pathways to developing more effective and therapeutic interventions for schizophrenia and other dopamine associated disorders. Finally, this work adds to our knowledge of dopaminergic modulation of cortical activity, specifically with respect to sex differences and hormonal regulation. The work lays a foundation for future investigations into the neurobiological substrates of schizophrenia and identifies targets in treatment strategy modifications to meet the unique needs of female patients.
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Diversity and Distribution Patterns of Ground-Dwelling Arthropods in the Santa Catalina Mountains, ArizonaMountains, with their rapid climatic and topographic variations along elevational gradients, offer ideal settings for investigating general patterns and factors associated with species diversity. While some common patterns and factors associated with species diversity may emerge across different systems, taxonomic groups are expected to exhibit differences along the same environmental gradient due to their distinct ecological requirements. However, relatively few studies have simultaneously examined multiple taxonomic groups within the same system, and it remains unclear whether commonalities exist in how species diversity varies with elevation and key environmental factors. In the Santa Catalina Mountains, elevational patterns of species richness were found to vary in different ground-dwelling arthropod groups. In line with this finding, combinations of different environmental factors are associated with variation in species richness in different ground-dwelling arthropods, suggesting that different taxonomic groups might not respond in the same way to the same environmental gradient. At the same time, average temperature and temperature range explained most of the variation in species richness in most groups, highlighting their predictive value in some but not all ground-dwelling arthropod groups. According to the climatic variability hypothesis, species range extent and distribution are determined by the climatic fluctuations a species can tolerate. Along gradients of climatic variability, species adapted to stable conditions are expected to not survive in areas with greater climatic fluctuations, and therefore present smaller range extents. In contrast, species inhabiting more variable climates are predicted to have broader range extents, as they can tolerate both climatically variable and stable regions. Since climatic variability generally increases with elevation, species range extents are expected to increase with elevation, a pattern known as Rapoport’s rule. Based on Rapoport’s rule, species richness is also expected to decline with increasing climatic variability, and consequently with elevation, since climatic specialists are gradually filtered out at higher elevations. Here, the validity of Rapoport’s corollaries is explored by establishing the relationship between species range extent, species richness, elevation, and climatic variability in different groups of ground-dwelling arthropods on the Santa Catalina Mountains. Although species range extent seemingly increases with increasing climatic variability as expected by the climatic variability hypothesis, this pattern does not result in elevational patterns of species range extent and species richness concordant with Rapoport’s rule. Contrary to species richness, variation in community structure is consistent across ground-dwelling arthropod groups. Pure turnover is the dominant component of beta diversity for all taxa, as beta diversity mostly varies according to biome identity along this elevational gradient. In line with this finding, environmental distances, but not geographic distances, correlate with turnover and overall beta diversity in all taxa, possibly suggesting that local environmental factors play a key role in shaping communities characterized by distinct species. This similarity in community structure and variation along environmental distance is further highlighted in Canonical Correspondence Analysis (CCA), where average temperature emerges as the main factor associated with patterns in community composition across all taxa. Based on these observations, we propose that environmental distance and average temperature might serve as a shared proxy for community structure differences across various arthropod groups in the Santa Catalina Mountains, and potentially other ranges within the Madrean Sky Island Archipelago.
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Modeling Growth of Chlorella sorokiniana by Changing CO2 Nutrient ConcentrationAlgae 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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Growth Without End: Exploring the Connections Between Teacher Evaluations and Professional Development in Secondary SchoolsTeacher evaluations and professional development are a required element of an educator’s professional life, yet there often appears to be little commonality of purposeful goal-making between the two, leading to a gap between expectations and teacher performance in the classroom (Ford et al., 2018; Katsarou & Tsafos, 2013; Leggett & Smith, 2019, Smylie 2014). The use or absence of effective teaching practices has a profound and cumulative impact on students (Cioè-Peña, 2021; Koyama & Menken, 2013; Laurillard, 2016; Leggett & Smith, 2019; Reddy, et al., 2017; Tate, 1997; Yosso, 2005). Therefore, the purpose of this study was to investigate secondary-school teacher evaluations and professional development systems to determine if an intended connection is perceived to exist between them, and how the systems are being used to meet the diverse needs of students and teachers in the classroom.To fulfill this purpose, I conducted a qualitative comparative case study, gathering teacher and administrator perspectives about their systems of teacher evaluation and professional development through semi-structured interviews with eleven participants. I coded the data using a thematic approach and analyzed the coded data using the framework of the cultural-historical activity theory (CHAT). The findings showed a clear desire for growth on the part of all participants and the impact of defining this growth as an object on the eventual outcomes for teachers and their students, as well as the role which a perception of support and knowledge play in fostering a willingness to access and implement effective teaching strategies. Keywords: Cultural-historical activity theory, teacher evaluations, professional development, effective teaching strategies.
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Using Behavioral Ecology To Minimize Human-Wildlife Conflict in a Major Metropolitan AreaUrbanization has transformed landscapes globally, fragmenting habitat and reducing natural resource availability for native wildlife populations. At the same time, the percentage of humans living in an urban environment continues to increase, bringing more humans in close contact with species facing limited resources. As a result, human-wildlife conflict is a growing concern worldwide. For many wildlife species, urbanization can result in habitat loss and population decline, as well as sickness, injury, or mortality resulting from conflict. I studied human-wildlife relationships in Tucson, AZ to better understand how wildlife in Tucson adapt to urbanization and gauge resident responses to wildlife in Tucson. My studies are focused on bobcat (Lynx rufus), coyote (Canis latrans), and collared peccary, or javelina (Pecari tajacu), due to government concern regarding human-wildlife conflict involving these three species. To identify root causes of human-wildlife conflict in urban environments and evaluate which strategies are most effective for reducing conflict, I conducted a literature review of non-lethal deterrent techniques used by urban residents and managers to mitigate human-carnivore conflict. I additionally deployed wildlife cameras in ephemeral stream corridors in and around Tucson to better understand how urbanization affects mammalian use of riparian corridors. Finally, I distributed a public survey assessing the efficacy of deterrent techniques promoted by state wildlife agencies. Human-wildlife conflict in Tucson overall appears to be low at present based on our study results; riparian corridors in and around the city may help alleviate habitat loss and fragmentation resulting from urbanization by providing natural resources and connectivity between natural areas. Restoration and preservation of riparian corridors may therefore offer a promising strategy for reducing human-wildlife conflict in urban centers.
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Subjectivity Is All You Get: Automatic Extraction and Application of Population Subjective ViewsPeople’s subjective views play an important role in complex systems. For instance, during COVID, people’s political views often guided their behaviors regarding masking and social distancing, which, in turn, impacted disease spread. In other words, people’s beliefs in this case lead to real world consequences. Including this type of relations into scientific modeling is a non-trivial task, which requires expensive manual data collection and analysis. In the three papers that comprise this dissertation, we take first steps towards automating this process. In the first paper, we define and provide an initial analysis for a new task—belief-consequence pair extraction—which we see as a special case of causal relation extraction, with the cause being subjective. We then focus on the first component of the belief-consequence link: beliefs, or subjective views, as expressed through natural language. In the second paper, we analyze and model subjective views through data collection and model training for the task of identifying sentences containing beliefs in natural language texts. We then further the analysis through the application of extracted beliefs to a downstream task in the third paper. In addition to analyzing subjective views themselves, we provide a discussion on subjectivity that occurs in other aspects of the work, particularly in data annotation and system output evaluation.
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Advancing Modular Gamma-Ray Cameras: Electronic Board Development for Silicon Photomultiplier Sensors and 4D (X, Y, Z, E) Position Estimation SoftwareThe rising number of people that are impacted by neurodegenerative disorders, including Alzheimer’s and Parkinson’s diseases, has increased the urgent need for disease-delaying or -reversing treatments. Non-invasive methods, such as SPECT and PET, are able to visualize imaging biomarkers that indicate presence of disease and also track the biodistribution of candidate pharmaceuticals to aid in drug discovery. For this purpose, AdaptiSPECT-C is a system that is designed to capture pharmacokinetic data for potential therapeutics for brain disorders. In this work, an electronics design for the silicon photomultipliers (SiPMs) and position estimation software for the gamma cameras in AdaptiSPECT-C were investigated. The intrinsic spatial resolution of a test module using a single SiPM is estimated using the Cram´er-Rao bound from Fisher Information Matrix (FIM) analysis under an assumption of Poisson statistics, using data from measured mean-detector-response functions (MDRFs). A 2D (X,Y) search algorithm for position estimation using signals from the test module is presented, along with a 4D (X,Y,Z, and E) contracting-grid position-estimation algorithm for use in the complete AdaptiSPECT-C cameras.
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Mexican Migrants Return South: Transborder Testimonials of Resilience and Adaptation in Mexico CityMigration 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 RegionThe 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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Implementing an Integrative Insomnia Toolkit for Psychiatric ProvidersPurpose: The purpose of this quality improvement project was to increase the knowledge of psychiatric healthcare providers of integrative insomnia treatments, increase their confidence in recommending them in practice, identify barriers to recommending integrative treatments, and evaluate the efficacy of the educational intervention. Background: Insomnia is a prevalent condition especially in the psychiatric population. Treatment typically involves pharmacological management that frequently involves adverse effects and/or dependency and tolerance. Many integrative interventions are evidence-based for insomnia but are rarely recommended by providers. Integrative interventions have the benefit of typically having fewer adverse effects and are relatively safe. Psychiatric providers may benefit from increased knowledge on integrative interventions for insomnia. Methods: This quality improvement project was a pretest-posttest quantitative design with an asynchronous educational presentation and a digital resource titled “Integrative Insomnia Toolkit for Psychiatric Providers.” The content included an overview of several evidence-based integrative interventions for insomnia and local resources for pertinent interventions. Results: Eight nurse practitioners and two physician assistants completed all components of the intervention. Posttest results showed an improvement in beliefs in efficacy of integrative treatments in insomnia and an increased likelihood of recommending integrative treatments. Additionally, most participants found the educational module helpful in increasing knowledge and were very motivated to recommend integrative therapies. Conclusions: This project suggests that an asynchronous educational module and Toolkit may be helpful in increasing knowledge of integrative treatment options and increasing likelihood to recommend them in practice to patients with insomnia in a psychiatric clinic.
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Bacterial Modulation of the Epithelial Barrier in Crohn's DiseaseCrohn’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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Biodiversity, Connectivity, and Impacts of Anthropogenic Barriers on Vertebrate Communities in the Mexico-USA BorderlandsThe Sky Islands region between Mexico and the United States has been recognized as a biodiversity hotspot due to the convergence of Neartic and Neotropical species (Coronel-Arellano et al., 2018; DeBano et al., 1995; Warshall, 1995). For mammals along the US-Mexico border, the northeastern portion of Sonora and the northwestern portion of Chihuahua are considered to be corridors for jaguars (Panthera onca), ocelots (Leopardus pardalis), and black bears (Ursus americanus), all of which use riparian and montane forests to move among the Sky Islands (Atwood et al., 2011; Grigione et al., 2009; Sierra-Corona et al., 2005). Large-scale developments in the region threaten landscape connectivity and the persistence of native wildlife populations (McCormack et al., 2009; Peters et al., 2018). The US-Mexico border wall bisects the distribution range of 346 species of nonflying terrestrial and freshwater animals, including 120 species of mammals, and will impact the cross-border movement of over 100 species under current climate scenarios (Peters et al., 2018; Titley et al., 2021). In this study, we address the ongoing fragmentation of one of the most diverse ecosystems in North America, focusing on the impacts of human barriers, discussing the possibilities of emerging techniques for monitoring terrestrial mammals faster and cost-effective, and investigating the spatiotemporal patterns of apex predators in the region. In chapter one, we focused on the international border between Arizona and Mexico, which traverses a vast landscape of extreme biodiversity. We aimed to determine how mammals' diversity and habitat use change across significant landscape features: the Cajon Bonito stream, the border wall, and the most transited highway in the area. We installed 85 camera traps and recorded 31 species of terrestrial mammals from 15 families and identified two different jaguar individuals and other cryptic species: the ocelot, porcupine and beaver. Diversity analyses showed that vegetation type influenced the composition of mammals in combination with the presence of cattle and distance to the road. The presence of cars, distance to the border wall, and effort, also affected the composition as non-interacting covariates. We found that human influence has a negative effect on the habitat use of mammals. Areas closer to the border are less used by larger mammals. However, mesopredators and small herbivores were more tolerant to disturbance and used sites closer to the border and dirt roads, but they exhibited a negative association with the presence of humans and sites closer to the border wall. Also, the presence of cattle negatively affected the habitat use and detectability of large and small carnivores. Our results highlight the need to keep bi-national connectivity for mammal populations using mountain corridors and prioritize locations that provide water sources to wildlife to mitigate highway and border wall impacts. This chapter is formatted for submission to the Science of the Total Environment journal. Given that traditional monitoring methods, particularly camera trapping, can be expensive, labor-intensive, and susceptible to equipment failure or theft, especially when elusive and low-abundant species of interest are present. In the second chapter, we explored the effectiveness of environmental DNA metabarcoding for monitoring terrestrial mammals as a potentially more cost-effective and faster alternative. We surveyed a 20 km section of the perennial Cajon Bonito stream in Mexico, deployed camera traps, and collected eDNA water samples at ten locations along the stream during wet and dry seasons. The camera traps operated continuously for 31 days before each eDNA sampling event. The results indicated that camera traps detected significantly more species (18 in the wet season, 17 in the dry) than eDNA (5 and 4 species, respectively). While some species detected via eDNA were also detected using camera traps, the beaver (Castor canadensis) was exclusively detected with eDNA. We analyzed the relationship between camera trap detections and eDNA detection, considering temporal proximity between detection events and spatial proximity. However, no significant correlation was found, contrasting with findings from more humid environments. The lack of correlation suggests that the factors influencing eDNA detection in arid environments, such as DNA persistence, degradation, and transport, make this technique less reliable than in humid environments. Also, the lower structural complexity of arid vegetation compared to humid environments might reduce DNA persistence and transport. While eDNA metabarcoding shows promise as a supplementary tool, camera traps remain more effective in assessing overall mammalian diversity in this arid ecosystem. Finally, in chapter three, we investigated the spatiotemporal ecology of three apex predators, black bears (Ursus americanus), pumas (Puma concolor), and jaguars (Panthera onca) in the US-Mexico borderlands. We used a 22-month camera trapping dataset, employing 85 motion-activated cameras placed along a riparian corridor and in a grid parallel to the international border. We focused on (i) spatial overlap, (ii) seasonal activity patterns, (iii) daily activity patterns, (iv) interspecific activity overlap, and (v) the effect of the presence of predators over two prey species, the white-tailed deer (Odocoileus virginianus) and the collared peccary (Dicotyles tajacu). We found spatial overlap between the three species of predators in riparian forests, and black bears and pumas in pine-oak forests, but pumas were typically the only apex predator in the scrublands and grasslands. We found distinct seasonal activity patterns among the three predators, with black bears showing peak activity in June, pumas exhibiting consistent activity throughout the year, and jaguars demonstrating peak activity from August to January. Daily activity was predominantly diurnal for bears and did not overlap with the two felids. Puma and jaguar activity overlapped, but puma activity peaked at dusk and jaguars during the night. The habitat use of both prey species responded positively to the presence of black bears but not to the felids. We suggest that given the dominance of black bears over both felids, prey species might be using those sites as a refuge from their other predators, exploiting avoidance of bears by the felids that describe the complexity of spatiotemporal partitioning.
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Novel Applications of Environmental DNA Analyses in the Tropical Eastern Pacific OceanEnvironmental DNA (eDNA) metabarcoding has revolutionized biodiversity monitoring and conservation biology by enabling the detection of species and genetic diversity from environmental samples. This dissertation addresses key improvements to the design, analysis, and interpretation of eDNA metabarcoding studies, applying these improved methods to studies of multitrophic ecology and blacktip shark genetic diversity in marine ecosystems in the Tropical Eastern Pacific Ocean. Key advancements include the development of the REGATTA bioinformatic method to reconcile taxonomic assignments with local species checklists, the application of Hill numbers to compare different facets of biodiversity, and the development of a non-invasive mitochondrial haplotyping assay for blacktip sharks. These novel analytical methods for assessing ecological interactions and spatiotemporal patterns of genetic diversity provide high-resolution insights into the conservation issues affecting scalloped hammerhead and blacktip sharks. The first study leverages these key advancements to the analysis of eDNA datasets to explore multitrophic biodiversity patterns in shark nursery bays of the Galápagos archipelago. By reconciling global and local taxonomic assignments and employing tools such as correlation analysis, co-occurrence networks, and predator effect analyses, this study provides detailed insights into the ecological drivers of fish and crustacean biodiversity and the influence of juvenile sharks on community composition in shark nursery bays. The second study introduces a novel mitochondrial haplotyping assay for blacktip sharks, demonstrating its efficacy in non-invasive monitoring of spatiotemporal patterns of intraspecific genetic diversity of this threatened top predator in coastal marine ecosystems. Together, these studies highlight innovative methodologies to enhance the specificity, sensitivity, and applicability of eDNA metabarcoding techniques in ecological and conservation research, providing robust tools to assess biodiversity at both intra- and interspecific levels. Ultimately, this work demonstrates the value of eDNA studies for generating comprehensive, non-invasive assessments of biodiversity and for informing ecosystem-based management and conservation efforts in complex marine systems.
