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Understanding Lake Tanganyika: Insights Into Climate, Circulation Dynamics, and Fishery Productivity Across Time Using Paleolimnological and Modeling Approaches
No full textLake Tanganyika, one of the world’s most biodiverse freshwater lakes and a vital resource for local fisheries, faces significant threats from climate change that jeopardize its ecological integrity and the livelihoods of dependent communities. This dissertation investigates the lake's thermal dynamics, circulation patterns, and historical limnological conditions using the Regional Ocean Modeling System (ROMS) and sediment core analyses. Our simulations show seasonal surface temperatures between ~25.8°C and ~27.8°C, consistent with observations, along with a concerning increase of up to 0.4°C at depths below 150 meters from 2001 to 2020. Primary upwelling occurs in the southern region during the dry season, while secondary upwelling occurs in the northern region during the wet season. Notably, there is previously unrecognized downwelling on the west side of the lake during September to November. Sediment core analyses reveal a warming trend since ~1850 AD, highlighting long-term climate change impacts on the lake's ecosystem. These trends correlate with global climate patterns, raising concerns about future effects on lake stratification and fishery yields. Enhanced productivity in pelagic zones is linked to deep vertical mixing, while productivity in littoral zones is influenced by increased riverine input during wetter phases. Under high-emission climate scenarios projected through 2100, lake surface temperatures could rise by up to 3.9°C, leading to significant changes in isotherm depths and thermal stratification, which may disrupt nutrient transport and adversely affect fish populations that provide approximately 40% of animal protein for local communities. Our findings emphasize the role of hydrodynamic and atmospheric interactions on nutrient distribution and ecological dynamics. They highlight the urgent need for adaptive management strategies, including community involvement in monitoring and international collaboration, to mitigate climate change impacts on Lake Tanganyika's ecosystem. This research offers valuable insights into the interplay between climate, hydrology, and biological productivity, informing strategies to preserve the ecological balance of Lake Tanganyika and support the livelihoods of millions reliant on its resources
FS8 Pressure Suit Test Data 2025011504
No full textImmediate accessThis item is made available by the University of Arizona Center for Human Space Exploration (CHaSE) with support from the University of Arizona Libraries. If you have questions, please visit https://www.b2science.org/center-human-space-exploration-chase
Sex-Specific Role of Damage-Mediated Signaling in Endothelial Homeostasis
No full textPulmonary arterial hypertension (PAH) is a progressive and fatal disease initiated by injured pulmonary artery endothelial cells (PAECs). Although PAH disproportionately affects females, males consistently exhibit a more severe disease progression and poorer outcomes. PAH initiates in response to PAEC damage, followed by inadequate repair and inflammation. The response to this damage includes the activation of the receptor for advanced glycation endproducts (RAGE), a multiligand receptor involved in inflammation, oxidative stress, and vascular injury, that mediates pro-survival and tissue-regeneration signaling. However, the precise role of RAGE in endothelial cell plasticity and remodeling remains poorly defined. This dissertation investigates how RAGE deficiency shapes endothelial fate and contributes to male-specific PAH pathogenesis. Using male and female whole-body RAGE knockout (RAGE KO) rats, we assessed PAH phenotype compared to age-matched wild-type (WT) rats as a control and examined the molecular, cellular, and physiological consequences of RAGE loss on the cardiopulmonary vasculature. Investigation of isolated endothelial cells from these rats revealed on a molecular level that RAGE deficiency activated both canonical (SMAD2/SMAD3 - SNAIL) and non-canonical (p38 MAPK - RhoA) TGF-β pathways, leading to Endothelial-to-Mesenchymal Transition (EndoMT), characterized by loss of CD31, upregulation of fibronectin, PDGFR-α, and enhanced cytoskeletal remodeling. These changes were associated with increased endothelial permeability and fibrotic deposition. Inhibition of TGF-β receptor I (TGFβ-RI) with SB431542 reversed these effects, restoring endothelial quiescence. PARSE single-cell transcriptomics analysis revealed broad sex-specific remodeling across endothelial, fibroblast, myofibroblast, and vascular smooth muscle cell populations, with male RAGE KO lungs showing expansion of proliferative, migratory, and ECM-remodeling cell states, while females maintained barrier-stabilizing and antioxidant programs. Functionally, male RAGE KO rats developed spontaneous pulmonary hypertension, evidenced by increased right ventricular systolic pressure (RVSP) and right ventricular hypertrophy (measured by Fulton index), along with pulmonary vascular wall thickening and interstitial fibrosis. Females were mainly protected, with minimal vascular remodeling and preserved endothelial integrity. Notably, hemodynamic differences persisted after gonadectomy, suggesting that male susceptibility is only partly hormone dependent and may involve an underlying endothelial vulnerability. At the organ level, insufficient RAGE signaling produced a mixed cardiopulmonary phenotype of pulmonary hypertension (PH), including features of Group 1 PAH (occlusive vascular remodeling), Group 3 pulmonary hypertension (fibrotic lung parenchymal remodeling), and secondary Group 2 pathology (left ventricular dysfunction). Histological and morphometric analysis revealed right ventricular fibrosis, diffuse lung collagen deposition, and left ventricular hypertrophy. These structural changes were accompanied by immune activation and metabolic reprogramming, as T cells from RAGE KO rats exhibited a glycolytic shift and expansion of proliferative and naive subsets, linking endothelial dysfunction to inflammatory and metabolic remodeling. Therapeutically, inhibition with SB431542 reversed key features of the disease, including decreased right ventricular systolic pressure (RVSP) and significantly reduced left ventricular hypertrophy (LV/TL). These findings confirm that TGF-β activation downstream of RAGE loss drives both pulmonary vascular and cardiac remodeling, and that targeting this pathway restores cardiopulmonary structure and function. Taken together, these findings identify deficient RAGE signaling as a key driver of male susceptibility to vascular endothelial injury and PAH. Loss of RAGE triggers a sex-dependent cascade involving TGF-β hyperactivation, EndoMT, and immunometabolic activation, all contributing to progressive pulmonary hypertension and biventricular remodeling. The RAGE KO rat thus represents a novel, spontaneous, and mechanistically integrative model of pulmonary hypertension across Groups 1, 2, and 3, offering critical insights into the molecular basis of male-predominant disease severity.Release after 01/05/202
Sustainable Urban Rehabilitation in Vulnerable Historic Contexts: Evaluating Alternative Intervention Strategies for Walkability, Safety, and Environmental Quality in Callao's Historic Center
No full textSustainable Built Environments Senior Capstone ProjectThe Historic Center of Callao, Peru, faces physical deterioration, high crime rates, and decades of failed rehabilitation attempts, creating urgent need for effective intervention strategies. This research evaluates three rehabilitation strategies to identify which approach optimally balances urban impact with implementation feasibility in this politically unstable, resource-constrained context. Literature shows that political discontinuity and insufficient funding have caused previous rehabilitation attempts to fail. Currently, the PDM Callao 2040 (Metropolitan Development Plan) includes planning provisions for this zone. However, researchers have not adequately examined intermediate strategies that balance viability and transformative impact.
This study employs methodological triangulation, combining semi-structured stakeholder interviews (n=10), focus group discussion (n=6), and weighted scorecard analysis across four dimensions: Walkability, Safety, Environmental Quality, and Viability. The research evaluates three strategies: A1 (Tactical), A2 (Intermediate combining pedestrianization, pocket parks, lighting, and façade rehabilitation), and A3 (Comprehensive transformation).
Findings demonstrate that alternative urban rehabilitation strategies in the Historic Center of Callao differ in perceived effectiveness for two main, interdependent reasons. The first is the capacity to address security, which is the community’s primary concern. The second is the perceived credibility of interventions within existing institutional constraints.
This research contributes the strategic implementation zone concept and provides evidence-based guidance for municipalities navigating viability-impact trade-offs, with broader applicability to Latin American historic centers.This item is part of the Sustainable Built Environments collection. For more information, contact http://sbe.arizona.edu
"From Scales to Systems: Multi-Level Determinants of the Body-Mind Burden in U.S. Children." Insights from the 2021-22, National Survey of Children’s Health (NSCH)
No full textIntroduction: Childhood obesity has become a major public health challenge, receiving worldwide attention due to increasingly strong evidence linking it to high risks for mental health disorders such as depression and anxiety. While we are aware of associations at the individual level based on previous research, there is a limited understanding of how these health outcomes are influenced by relational, community and structural dimensions. Children's health is hypothesized to be influenced by a multi-level, interplay of factors, including interpersonal, community, and policy-level factors in a socio-ecological framework. This research employs this model to facilitate a comprehensive, multi-tiered analysis of how various moderators at different levels impact body weight and subsequent mental health outcomes among children aged 6 to 17 years in the United States. Through the simultaneous consideration of insights from multiple levels, all gathered in a unified dataset and analytic framework, the current research presents a new, integrative perspective on the nexus between mental health and body weight within complex social systems. Methods: We utilized cross-sectional data from the 2021–2022 National Survey of Children’s Health (NSCH) in a nationally representative sample of 40,820 children. The primary outcomes were lifetime diagnoses of depression and anxiety. Body Mass Index (BMI) was classified into underweight, normal weight, overweight, and obese. A series of survey-weighted logistic regression models were utilized to estimate the associations between BMI and mental health diagnoses, incorporating interaction terms to evaluate the moderating effects at three distinct levels. • Interpersonal Level: The variables included were exposure to bullying, ability to form friendships, mental health of parents, and family resilience. • Community Level: The community level moderators included neighbourhood safety, supportive environment, after-school activity, and community participation. • Policy Level: Insurance gaps, type and adequacy were included as moderators. All of the models were adjusted for age, sex, race/ethnicity, and federal poverty level. Stratified analyses were also conducted to explore effect modification further. Results:
In all the models, obesity was significantly associated with increased odds of depression and anxiety. Obese children had 2.08 times higher odds of depression (Adjusted Odds Ratio( aOR) = 2.08, 95% Confidence Interval (CI): 1.64–2.64) and 1.48 times increased odds of anxiety (aOR = 1.48, 95% CI: 1.25–1.76) than children of normal weight. Interpersonal-Level Outcomes
Obesity was significantly associated with higher odds of both depression and anxiety in children aged 6-17 years. Obese children had 2.08 times higher odds of depression (aOR 2.08; 95% CI: 1.64-2.64) and 1.48 times higher odds of anxiety (aOR 1.48; 95% CI: 1.25-1.76) compared to normal-weight peers. Significant moderating effects were observed for depression (adjusted for age, sex, race/ethnicity and poverty levels): never bullied (aOR = 2.12; 95% CI: 1.45-3.11), maternal mental health (aOR = 1.70; 95% CI: 1.70- 2.70), and paternal mental health (aOR = 2.54; 95% CI: 1.51-4.29). For anxiety, moderating effects were seen for making friends (aOR = 1.91; 95% CI: 1.13-3.22) and father’s mental health (aOR = 2.14; 95% CI: 1.34-3.41). Community-Level Observations
Obesity was associated with higher odds of depression in both supportive (aOR=1.53, 95% CI: 1.16–2.02) and non-supportive (aOR=2.57, 95% CI: 1.81–3.65) neighbourhoods, though overlapping CIs indicate no statistically distinct difference. For anxiety, obesity was significant only in non-supportive environments (aOR=1.81, 95% CI: 1.39–2.35). Overweight showed weaker associations, and underweight was non-significant. After-school inactivity, volunteering, and neighbourhood safety were confounders without interactive effects. Policy-Level Results
Children with obesity showed significantly higher odds of anxiety (aOR = 1.43, 95% CI: 1.18–1.72) and depression (aOR = 1.92, 95% CI: 1.52–2.43). There was a notable interaction between BMI and insurance consistency (p = 0.016) for anxiety. Among children with consistent insurance, those who were overweight (aOR = 1.59, 95% CI: 1.23–2.06) and obese (aOR = 2.12, 95% CI: 1.66–2.70) had increased anxiety risk, whereas children with coverage gaps had lower odds (aOR = 0.16, 95% CI: 0.04–0.67), indicating possible underdiagnosis. Insurance adequacy was also significant: children with “usually” adequate coverage had 56% higher odds of depression (aOR = 1.58, 95% CI: 1.28–1.96), and those with “sometimes/never” adequate coverage had more than double the odds (aOR = 2.63, 95% CI: 2.11–3.29). Conclusions: These findings strongly maintain the argument that the psychological well-being among children with obesity is influenced by a multifactorial interaction among various social determinants, rather than a primarily biological or behavioral determinants. This demonstrates that the link between mental health and childhood obesity largely depends on the environments in which children are cared for, learn, and live. Findings are in support of a multi-level understanding, as well as a multi-level intervention in, the condition of syndemic mental health disorder and child obesity. Interpersonal processes bullying, friendship difficulties, and parental mental health have immediate effects on the psychological burden of obesity. These emphasize the need to strengthen the support systems of peer groups and families, as well as to introduce parent-centred features in treatment. Neighbourhood environments are central, with the support of the neighbourhood significantly buffering the risk of obesity. These findings suggest that place-centred initiatives—such as promoting strong, safe, and cohesive communities and easily accessible extracurricular experiences could be crucial safeguards against psychological distress. Insurance consistency, one of the structural factors of health, was a strong moderator of depression and anxiety. Varying or inadequate insurance not only can hinder treatment, but can also result in loss of diagnosis, consequently delaying proper intervention. For that reason, the importance of advocating policies that offer sustained, complete mental health coverage for children—most importantly, children with chronic conditions such as obesity—takes centre stage. In short, treating childhood obesity in isolation will not suffice. An integrative model that simultaneously concentrates on interpersonal relations, community arrangements, and the introduction of new policies can prevent the transgenerational and systemic circuits between affective well-being and body weight. Multidomain intervention can provide early detection, equal treatment, and improved prognosis in at-risk children.Release after 01/06/202
Program Evaluation of Virtual Rn (ViRN) Integration: Assessing Adoption, Quality Process, and Nurse Satisfaction in Inpatient Care
No full textBackground: The increasing complexity of healthcare and persistent nursing shortages have driven the adoption of creative care models such as the Virtual Registered Nurse (ViRN). ViRN leverages telehealth technology to provide remote clinical assistance, patient monitoring, and education to support the bedside nurses in acute care settings. By offloading admission, discharge, and patient education tasks, ViRN aims to enhance workflow efficiency, improve patient and nurse satisfaction, and medication safety.
Purpose: This project evaluated the ViRN program at an academic medical center health system hub site, focusing on four objectives: adoption of ViRN for admissions and discharges, impact on heparin medication safety, nurse satisfaction, and overall integration into inpatient workflows. The goal was to assess the effectiveness of ViRN in optimizing nursing processes and supporting evidence-based program refinement and expansion. Methods: A qualitative and quantitative evaluation with descriptive statistics was conducted across three medical-surgical units (72 beds total). Quantitative data included electronic health record (EHR) reports on ViRN-assisted admissions/discharges and safety event records for Heparin administration. Nurse satisfaction was measured via an anonymous survey (Likert scale and open-ended questions). Qualitative thematic analysis captured nurses’ experiences and suggestions. All data were de-identified, and Institutional Review Board (IRB) approval was obtained. Results: From May 2023 to May 2025, ViRN assisted with 62.7% of admissions and 23.1% of discharges, with unit-level variability. Heparin safety events decreased post-implementation, with ViRN providing critical “good catches” and protocol adherence. Surveyed nurses (59% response rate) reported high satisfaction with ViRN’s accessibility, workflow support, and time-saving benefits, though some cited challenges with technology and role clarity. Overall ViRN utilization reached 41.9%, indicating moderate integration. Conclusions: ViRN integration improved workflow efficiency, medication safety, and nursing satisfaction in inpatient care. While adoption for admissions was high, discharges and overall utilization varied by unit, highlighting opportunities for targeted improvement. Continued monitoring, staff engagement, and communication enhancements are recommended to maximize ViRN’s impact and scalability
Smarter, Leaner, Faster: Practical Efficiency for Democratizing Large Language Models
No full textLarge language models (LLMs) deliver impressive capabilities, yet their practicality is constrained by three major bottlenecks: (1) memory and compute demands that make loading and using LLMs impossible on commodity hardware; (2) limited tokens/sec during decoding, which caps delivered throughput under real use-cases; and (3) computational overhead from unnecessarily and redundant reasoning traces, which increases the tokens-per-answer required and serving cost. This dissertation advances a clear objective: decouple capability from raw scale. We show that models can be improved and made smarter, leaner, and faster leading to more accessibility without sacrificing accuracy. Our contributions span three levels. (i) High tokens/sec generation: CopySpec identifies repeating patterns in the context and enables up to a 3.08x increase in tokens/sec. (ii) Concise reasoning: ConciseRL is a reinforcement learning framework that optimizes for concise and sufficient reasoning traces that reduce tokens-per-answer by up to 31x with 7 extra precision points. (iii) Model compression for memory and compute: Variable Layerwise Quantization assigns per-layer bit levels according to two different importance signals, shrinking the footprint of the model with minimal decrease in performance, while Dynamic LLM Slicing completely removes redundant parts of layers based on similar layer importance metrics, cutting inference compute and the memory requirement retaining performance. These techniques work to realign the cost curve of large language models. By converting redundancy into cheap tokens, allocating token budgets to only the problems that matter, and trimming excess size, they increase delivered tokens/sec, shrink the required tokens-per-answer, and reduce the total footprint while preserving output quality. Because each mechanism targets different stages of the pipeline (generation, reasoning, capacity), they compose easily: fewer tokens-per-answer interacts synergistically with higher per-step throughput, and a smaller model allows these gains to be used on commodity hardware. The result of these techniques is a push toward democratization of frontier LLMs while retaining high quality on modest budgets instead of highly expensive infrastructure
Reduce Inappropriate Cardiac Stress Testing by Improving Adherence to Educational Guidelines
No full textPurpose: This quality improvement initiative aimed to educate primary care providers about theindications and contraindications for nuclear and non-nuclear cardiac stress testing to promote appropriate test selection and improve patient outcomes. Background: Cardiovascular disease is the leading cause of death in the United States, with coronary artery disease responsible for more than half of all cardiovascular events in adults under 75 (Chou, 2015). Although cardiac stress testing is essential for evaluating CAD, 5%–25% of imaging tests are performed inappropriately, resulting in unnecessary radiation exposure, increased costs, and potential patient harm (Chaudhuri et al., 2015). Selecting the correct test relies on following evidence-based guidelines and accurately assessing patient symptoms and clinical status. Methods: A pre-implementation chart audit revealed that 4–13% of stress tests required modification due to inappropriate orders, highlighting the need for provider education. Using a
Plan-Do-Study-Act framework, a 30-minute educational intervention was delivered to four primary care providers. Content included types of stress tests, indications, contraindications, and a clinical flowchart tool to guide test selection. Pre- and post-intervention surveys assessed knowledge, confidence, and intent to apply the materials. A four-week post-implementation chart audit evaluated improvements in ordering accuracy. Results: Provider understanding of stress test types improved from 50% agreement before the intervention to 100% agreement or strong agreement afterward. Confidence in selecting appropriate tests rose from 25% to 75%. Knowledge of contraindications increased from 25% to 100%. Confidence in interpreting guidelines grew from 0% to 75%. All providers reported they would use the flowchart in practice. Post-implementation audit findings indicated that 87.5% (7 of 8) of stress test orders were appropriate. Conclusion: Targeted education and practical decision-support tools significantly improved provider knowledge, confidence, and accuracy when ordering cardiac stress tests. Using evidence-based guidance can lower unnecessary imaging, improve workflow efficiency, and reduce patient risk
Catastrophic Flooding in Osuga Valles, Mars: Implications For Its Paleoflood Hydrology and Formation
No full textSatellite imagery of Mars has shown large flood-like features known as outflow channels across its surface. Previous studies have used a variety of techniques involving complex 1D equations and 2D models for outflow channels in Chryse and Elysium Planitia to estimate the magnitudes and depths of floods. In this study, we use both 1D and 2D flow equations and the 2D computer hydraulic model HEC-RAS version 6.6 to estimate stage-discharge relationships within Osuga Valles. Additionally, we use 1D groundwater and fracture flow equations, and the 2D thermal model HYDROTHERM to simulate pressure and temperature changes within the subsurface. The site of interest is Osuga Valles, an outflow channel that contains unique features suggesting pressure-dominated floods from groundwater that cover approximately 168 km of fluvially eroded channels. The varying depths along the channel suggest the floods are catastrophic, excavating between 250 to over 1,000 meters in depth. All channels appear to terminate into a relatively small collapsed basin, without indication of any surface flows beyond this terminus. High-resolution Digital Terrain Models (DTM) from HRSC, CTX and HiRISE are used to capture cross-sectional profiles and relative elevations of Paleo Stage Indicators (PSI’s) to provide supporting evidence for flood depths. From the HEC-RAS results, we find that the roughness of the channel bed in Osuga Valles does not greatly influence the depth for each flow rate, and the last flood that most likely filled the channel based on PSI is approximately 5 x 10^7 m3/s. However, our subsurface analysis counters this and suggests the last flood was several orders of magnitude smaller than simulated with HEC-RAS and short-lived. Permeabilities of the fractures within the aquifer for producing such large-scale flooding range from 1.4 x 10^-6 to 2.5 x 10^-6 m2, which converts to over ~1,400,000 darcies