113588 research outputs found
Sort by
Unpacking the Impact of Policy on Practice: Effect of the 2018 UNOS Policy Change on the Practice of Heart Transplantation
No full textBackground: This study examines the impact of the 2018 United Network for Organ Sharing (UNOS) policy change on heart transplant candidates in the United States. Methods: Changes in waitlist times, patterns of MCS use as a bridge to transplantation, post-transplant survival, and hospital readmission trends before and after the policy implementation were analyzed. Analysis of heart transplant recipients transplanted between January 2013 and June 2022, classified into two periods: Period A (pre-policy) and Period B (post-policy). Statistical methods such as binary logistic regression and ARIMA modeling were applied to assess trends and outcomes. Results: There was increased reliance on temporary MCS, specifically IABP and ECMO, following the policy change. The use of IABP at listing rose from 5.1% in Period A to 15.5% in Period B, while ECMO use increased from 1.1% to 3.6%. At the time of transplant, IABP usage surged from 7.6% to 27.8%, and ECMO use increased from 1.0% to 5.6%. Regression analysis confirmed that the odds of using IABP and ECMO at transplant were significantly higher in Period B (OR 5.36 and OR 7.39, respectively, p < 0.001). Sub-group analysis on escalation revealed that transitioning from IABP to ECMO significantly increased adverse post-transplant outcomes, including higher rates of dialysis (33.1% vs. 15.0%, p < 0.01), prolonged ventilation (35% vs. 1%, p < 0.01), and reduced survival at 1000 days (61.6% vs. 83.6%, p < 0.01).
Analysis comparing durable LVAD with temporary MCS revealed that patients bridged with durable LVADs, had lower rates of adverse outcomes, including reduced requirements for prolonged inotropes (43.1% vs. 57.6%, p < 0.01), dialysis (14.2% vs. 17.9%, p < 0.01), and chronic steroid therapy (3.6% vs. 5.8%, p < 0.01). While stroke incidence was slightly higher in the LVAD group (4.1% vs. 3.9%, p = 0.19), this increase was not statistically significant. Additionally, 1000-day survival was comparable between temporary MCS (82%) and durable LVAD (80%) groups (p = 0.02), indicating that LVADs offer a viable alternative to temporary support strategies. Conclusion: The 2018 UNOS policy change has led to significant shifts in MCS utilization, with an increased reliance on temporary support. However, careful consideration must be given to escalation strategies, as transitioning from IABP to ECMO is associated with worse post-transplant outcomes. Prioritizing the use of durable LVADs, particularly HM3, as a primary bridge to transplant rather than escalating from temporary devices such as IABP and ECMO is recommended. The addition of ECMO to IABP significantly reduces survival, making it a less favorable strategy. Early implantation of durable LVADs may improve patient outcomes and reduce complications associated with prolonged temporary MCS use. Durable LVADs, particularly HM3, may be considered the preferred bridging strategy to optimize long-term survival and reduce perioperative complications in heart transplant candidates
Segmenting Fluorescent-Dyed Cell Images Using Mask R-CNN
No full textThis project explores the impact of contrast-related hyperparameters on cell detection performance in fluorescent-labeled images. We focused on optimizing model architectures and training strategies, with an emphasis on static and dynamic auto-contrast methods. Our findings show that SGD with momentum consistently outperformed other optimizers across dynamic auto-contrast configurations. Static auto-contrast methods, particularly those using Pillow and PyTorch, enhanced edge detection, but occasionally hindered the visibility of fluorescent Kog1 bodies crucial for classification. Kernel size variations in the Basic Convolutional Block module did not significantly affect performance. Data augmentation proved effective in improving model generalization on a small dataset. Among the dynamic auto-contrast models, the Baseline Mask R-CNN model provided the best performance. In support of our hypothesis, static auto-contrast methods improved segmentation accuracy by enhancing edge definition and feature visibility. Our best-performing model achieved segmentation accuracy within 5% of ACCT, a state-of-the-art model for brightfield images, demonstrating the value of contrast-aware preprocessing in fluorescent image segmentation
Diffusion Connectome Analysis in a Rat Model of Hypertension
No full textWhile hypertension is recognized as a significant risk factor for cerebrovascular diseases(e.g., Alzheimer’s Disease and dementia) and cognitive decline, its impact on brain connectivity is not fully understood. A prior study investigated the effects of induced hypertension on the macrostructural and microstructural anatomy of Fischer 344 Cyp1a1-Ren2 transgenic rats using diffusion MRI (dMRI). Results showed that while hypertension resulted in end-organ damage in the heart and the kidney, the brain remained unaffected in terms of volume and microstructural characteristics. The purpose of this study is to further investigate the effects of hypertension on structural white matter connectivity in the same transgenic rat model using connectome analysis. Connectomes were generated from diffusion data collected and processed in the previous study using probabilistic tractography. Structural connectivity was quantified and compared between and within normotensive and hypertensive rats at baseline and 10 weeks across four regions of interest (left cortex, right cortex, left hippocampal CA subfields, and right hippocampal CA subfields). No significant differences were observed in structural connectivity across these four regions, further establishing the findings reported in the prior study. These findings indicate that the brain may implement intrinsic protective mechanisms to preserve structural connectivity and mitigate damage from hypertension, even in the presence of systemic end-organ damage
Using Performance-Based Insights into the Sorghum Microbiome to Advance Microbiome-Mediated Solutions in Arid Agriculture
No full textIncreasingly, the crop microbiome is looked to as a novel toolkit to combat abiotic stressors while sustaining agricultural productivity, essential to overcoming ecological challenges associated with agricultural intensification in a changing world. Despite recent advances in characterizing species that comprise plant microbiomes, specific ways by which a given microbiome contributes to crop performance remains unclear. Broadly defined, the endophytic microbiome consists of microbes that inhabit the interior of plant tissues without causing symptoms of disease. As such, endophytes in that establish in roots and leaves form intimate relationships with their plant host, at times existing as commensals but in other cases altering plant phenotypes. Because endophytes have a long evolutionary history with plants, they depend on plants complete their life cycle, and they either evade or overcome plant defenses to establish, it is thought that many can be beneficial for plant growth and resilience to stress. However, knowledge gaps remain a challenge for applications of endophytes: how do they vary among genotypes of plants? What are their growth-influencing traits? Do potentially beneficial endophytes harbor genes associated with production of undesirable secondary metabolites? How can endophytes be selected and delivered to plants effectively for improvements in agriculture? This dissertation centers on characterizing the fungal and bacterial endophytic microbiome of sorghum, a stress-resilient cereal crop, and developing a pipeline for selection of beneficial root-associated bacteria for plant growth and yield promotion. Together with my coauthors, I show that the sorghum root microbiome shifts under drought, and that the microbiome of higher-performing lines may be especially responsive to drought. However, drought does not remodel microbe-microbe interactions, suggesting that host-microbe interactions underlie microbiome shifts under environmental stress. To test this prediction, I, with my colleagues, analyzed the root metabolome and interpreted its relationship to specific microbial taxa. Relative to lower-performing lines, higher-performing sorghum accumulated a lower level of flavonoids, which are members of a phytohormone class strongly linked to defense and may facilitate establishment of root-endophytic microbes with plant-growth promoting potential. To understand the genomic architecture of representative root-associated bacteria, my colleagues and I used whole-genome sequencing to explore secondary metabolite production and other genomic features of microbes associated with high-performing sorghum from field conditions in Arizona. Finally, we evaluated a biobank of sorghum cultures, testing the prediction that those associated with higher-performing plants would be more likely to show plant growth-promoting phenotypes in vitro, including phosphate solubilization, auxin production, ammonium production, and siderophore activity. Based on bioassay results, a suite of microbial strains was used in a greenhouse and field experiment to evaluate the potential of microbial inoculants to promote desirable phenotypes in sorghum. We found that microbial inoculants associated with plant growth promotion were successful at promoting biomass and yield in a field-grown sorghum hybrid line, with differences relative to greenhouse results suggesting a strong impact of field-relevant stressors or other conditions. Overall, this work strengthens our understanding of how plant microbiomes relate to plant phenotypes, and provides a framework for a translatable approach to manipulate microbes for field applications
Writing the Identity of the Homeland: Indigeneity and National Identity in Salvadoran Literature
No full textBefore the 1990s, El Salvador’s national identity had long been characterized as completely miscegenated through the claimed disappearance of all indigenous people by the state. Strongly reinforced through an ethnocide in 1932, the myth of complete mestizaje in El Salvador was cemented in the Salvadoran imaginary and beyond, aligning with Eurocentrism and neoliberal policies that structured dominant concepts of nation-building in Latin America at the time (DeLugan 2012). After the end of El Salvador’s civil war, the emergence of a regional transnational indigenous movement (Tilley 2002) marked a new period of nation-state and collective identity construction where the Salvadoran state no longer outright denies the existence of indigenous peoples in El Salvador, but continues to have inconsistent approaches, attitudes, and formal narratives regarding indigeneity and indigenous history. With formal and informal sites of cultural knowledge transforming under international networks and standards, sites of cultural production like national literature provide a point of reflection for the Salvadoran imaginary’s construction of, and relationship to, indigenous and nation-state identities. Through the poems of the Salvadoran anthology Tzuntekwani, I analyze the rhetoric of contemporary national literature that constructs indigenous identity around specific sites of state violence, certain Mesoamerican and local cultural markers, geographic location and environment, and socioeconomic marginalization. This thesis aims to understand the relationship between collective conceptualizations of national identity, or identities, in El Salvador’s formal state rhetoric and national literature in the 20th and 21st century
Case Study: Academic Capitalism & Academic Coaches’ Working Conditions, Emotional Labor, & Compassion Fatigue
No full textStudent affairs within higher education encompasses a wide range of professions, including academic coaching. Although most academic coaching programs have only been around for the past 20 years, much of the research has focused on its justification and value as a profession by evidence of students’ increased grade point averages (GPAs), retention rates, and goal attainment (Alzen et al., 2021; Capstick et al., 2019; Losch et al., 2016; Vanacore & Dahan, 2021). There remains a gap within the literature that falls short of examining the everyday experiences of academic coaches within university settings. This critical case study looked to give a platform for academic coaches to voice their experiences with their working conditions, emotional labor, and compassion fatigue. Through the means of 22 qualitative semi-structed interviews, the findings concluded that University of Arizona (UA) academic coaches exist within an institutional environment that promotes and upholds academic capitalist structures. This negatively effects their working conditions, while also advancing elements of emotional labor and compassion fatigue. Although collectively experienced across the university, department affiliation dictates the different ways or levels to which these elements of working conditions, emotional labor, and compassion fatigue are felt by academic coaches. Through evidence of these findings, recommendations and implications for academic coaches and university management are provided
Discursive Constructions Of Homosexuality In Kenya: A Corpus-Driven Discourse Analysis Of The German Press
No full text(Recent) legislations surrounding LGBTQ+ discourses in Kenya and beyond have invited visibility and coverage from both local and international media outlets. Building on studies that examine LGBTQ+ social justice and human rights, this study analyzes how German Newspapers in particular frame news surrounding homosexuality in Kenya. In this study, I use LexisNexis, a corpus data source to source newspapers that thematize Homosexualität in Kenia between 2014 to 2024 and then I apply Critical Discourse Analysis (CDA) by Van Dijk, to interpret and analyze the results through a macrostructural perspective. The study quantitatively employs a corpus-based analysis, in which Sketch engine, a corpus linguistic tool is used to determine concordances, collocations, and keyword analysis. The study borrows from qualitative theories in which the concepts of Representation by Stuart Hall and the Frankfurt school theory by Theodore Adorno are applied. The results highlight the dominance and intersection of discourses such as the prevalence of homophobia, Western influence, the discursive positioning of Uganda and South Africa, and the reporting of a collective Africa. The study is relevant in unraveling the discursive strategies that inform and shape how the state of homosexuality in Kenya is reported about from a German newspaper perspective. It is necessary to examine German media perspectives of homosexuality in Kenya to gain a more nuanced and historical understanding of how these discursive patterns of German witnessing about Africa get made/remade in media contexts
IMPACT OF CLIMATE CHANGE ON WHISKY PRODUCTION
No full textClimate change is altering environmental conditions critical to Scotch whisky production, specifically optimal precipitation and temperatures for barley yields. This study employs geospatial analysis to assess climate patterns and agricultural shifts within whisky-producing regions of Scotland. Climate data from the UK Met Office and agricultural reports from the Scottish Government are used to analyze temperature and precipitation trends impacting barley farming. Statistical modeling determines correlations between climate trends and whisky production factors, with choropleth maps and temporal analysis graphs visualizing the findings. The results provide insights into the vulnerabilities of whisky production and inform adaptation strategies for distilleries. Understanding these environmental impacts is crucial for sustaining the industry amid ongoing climate shifts.This item is part of the MS-GIST Master's Reports collection. For more information about items in this collection, please contact the UA Campus Repository at [email protected]
ASSESSING EROSION CONTROL SUITABILITY WITH NORMALIZED DIFFERENCE INFRARED INDEX IN A SEMI-ARID WATERSHED
No full textAccurate assessment of soil moisture and infiltration capacity is essential for watershed management in semi-arid regions like Southern Arizona, USA. This study investigates the use of the Normalized Difference Infrared Index (NDII) to identify areas of low infiltration within the Walnut Gulch Experimental Watershed (WGEW), focusing on the driest (2020) and wettest (2022) monsoon seasons between 2015 and 2025. NDII, a remote sensing index sensitive to vegetation water content, serves as a proxy for root zone soil moisture. This study uses Landsat 8/9 imagery to analyze NDII changes between May and October and classify areas from low to high infiltration response. Comparing NDII change values across contrasting years highlights zones with persistent low infiltration. Identifying these areas is the first step toward developing a restoration strategy for semi-arid watersheds. A multi-criteria suitability analysis— incorporating slope, terrain ruggedness, road accessibility, and soil moisture data— prioritizes locations for erosion control structures (ECS). ECS offer a cost-effective restoration method by reducing water velocity and enhancing infiltration potential. Integrating NDII dynamics with hydrological and terrain factors provides a scalable, data-driven framework to support sustainable watershed restoration in arid environments.This item is part of the MS-GIST Master's Reports collection. For more information about items in this collection, please contact the UA Campus Repository at [email protected]
Future of the Colorado River – Southwest Ag Summit
No full textThis article, published in the VegIPM Newsletter (Vol. 16, No. 4), previews discussions at the 2025 Southwest Ag Summit focused on the Colorado River, highlighting key sessions with policymakers and water leaders addressing negotiation challenges.Documents in the Arizona Pest Management Center collection are made available by the Arizona Pest Management Center (APMC) and the University Libraries at the University of Arizona. For more information about items in this collection, please contact https://acis.cals.arizona.edu/about-us/arizona-pest-management-center