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- Meteoritics & Planetary Science, Volumes 37-44 (2002-2009) are now publicly available in the repository.
- Radiocarbon, Volumes 1-54 (1959-2012) are now publicly available in the repository.
- Theses from Spring/Summer 2020 Honors College graduates are now publicly available in the repository.
- Rangeland Ecology & Management/Journal of Range Management, Volumes 1-66 (1948-2013) are now publicly available in the repository.
- More than 8,400 journal articles from University of Arizona faculty, staff and researchers have been made available since the implementation of the UA Open Access Policy (April 2016). You can find these articles in the UA Faculty Publications collection - thank you to all our article authors and contributors!
- Senior capstones from the Sustainable Built Environments program are now available in the Campus Repository.
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Perceived Barriers and Facilitating Factors in Implementing Delayed School Start Times to Improve Adolescent Sleep PatternsBACKGROUND: Most adolescents in the United States do not obtain sufficient sleep. Early school start times play a significant role in adolescent sleep deprivation. Most primary and secondary schools begin classes earlier than the 8:30 am. Perceived barriers to implementing a delayed school start time have been suggested in the literature but have not been quantified. This study explored perceived barriers and facilitating factors for implementing delayed high-school start times. METHODS: A cross-sectional study. School administrators who had delayed their school start times were invited to complete an online questionnaire ranking the perceived barriers and facilitating factors for implementing the delayed start times. RESULTS: Most commonly cited perceived barriers were lack of a tiered bus system, school athletes missing more afternoon classes, and less time after school for athletics. Most commonly cited facilitating factors were school-administrator involvement in the decision-making process and sleep education for family members and school administrators. CONCLUSIONS: Participants found that providing sleep education to fellow administrators, teachers, school staff members, families, and students and including them in the decision-making process positively facilitated the implementation of delayed school start times. Perceived barriers to implementation may be overcome with support from stakeholders and planning committees. © 2020, American School Health Association
Assessment of High-Temperature Effects on Hypersonic Aerothermoelastic Analysis using Multi-Fidelity Multi-Variate SurrogatesThis study investigates the impact of the high-temperature effect, esp. the real gas effect and the chemical reactions, on hypersonic aerothermodynamic solutions of double cone and double wedge configurations, as well as the aerothermoelastic behavior of a double wedge configuration in hypersonic flow. First, a high-temperature computational fluid dynamics code was benchmarked and correlated with experimental results, emphasizing the impact of high-temperature effects as well as turbulence modeling on heat flux prediction. Subsequently, an aerothermal surrogate based on the multi-fidelity Gaussian process regression method was developed. The model achieves a balance between model accuracy and computational cost of sample generation, using the combination of a few high-fidelity sample and many low-fidelity samples. Finally, the new aerothermal surrogate was applied to study the impact of the hightemperature effect on the aerothermoelastic response of a hypersonic skin panel, emphasizing the necessity of the accurate characterization of the localized heat flux for reasonable assessment of the response of a compliant structure in high-speed high-temperature flowfield.
An Innovative United States–Mexico Community Outreach Initiative for Hispanic and Latino People in the United States: A Collaborative Public Health NetworkCollaborative partnerships are a useful approach to improve health conditions of disadvantaged populations. The Ventanillas de Salud (VDS) (“Health Windows”) and Mobile Health Units (MHUs) are a collaborative initiative of the Mexican government and US public health organizations that use mechanisms such as health fairs and mobile clinics to provide health information, screenings, preventive measures (eg, vaccines), and health services to Mexican people, other Hispanic people, and underserved populations (eg, American Indian/Alaska Native people, geographically isolated people, uninsured people) across the United States. From 2013 through 2019, the VDS served 10.5 million people (an average of 1.5 million people per year) at Mexican consulates in the United States, and MHUs served 115 461 people from 2016 through 2019. We describe 3 community outreach projects and their impact on improving the health of Hispanic people in the United States. The first project is an ongoing collaboration between VDS and the Centers for Disease Control and Prevention (CDC) to address occupational health inequities among Hispanic people. The second project was a collaboration between VDS and CDC to provide Hispanic people with information about Zika virus infection and health education. The third project is a collaboration between MHUs and the University of Arizona to provide basic health services to Hispanic communities in Pima and Maricopa counties, Arizona. The VDS/MHU model uses a collaborative approach that should be further assessed to better understand its impact on both the US-born and non–US-born Hispanic population and the public at large in locations where it is implemented. © 2021, Association of Schools and Programs of Public Health.
Comparison of Mixed Models and Paired T-Test for Analyzing Crossover Clinical Trials in the Presence of Missing DataAB/BA crossover clinical trials are popular designs that can achieve high power with a lower number of subjects than other randomized control trial designs. They are often analyzed using paired t-test or mixed models, and like many clinical trials, are often impacted by missing data. Mixed models have been shown to produced more powerful and unbiased results in the presence of missing data than t-tests for other designs, but these two approaches have not been compared in crossover trials. We conducted a simulation study to compare the bias and power of paired t-tests and mixed models when analyzing an AB/BA crossover clinical trial in the presence of missing data. Several different missing structures were simulated under two within-subject correlations, ρ =0.3 and ρ =0.7. Both methods performed similarly when analyzing complete data, but the mixed model produced both equal or less bias estimates and higher power than the paired t-test under all simulation scenarios. In the worst-case scenario we considered, the t-tests resulted in percent bias up to -105% and power as low as 5% compared the mixed model’s percent bias of 1% and 57% power. In less severe cases, both methods had 0% bias, but mixed models still achieved an absolute power gain of 2%-6%. In the presence of missing data, the mixed model achieved higher power than the paired t-test under all simulated scenarios. The mixed model also achieved equal or less bias under all simulated scenarios. Therefore, mixed models should be used over paired t-test when analyzing AB/BA crossover clinical trial in the face of missing data.
Reclaiming Mining Lands in Southern Arizona: A Scientific and Policy Inquiry towards ResiliencyCopper is critical to the sustainability of the modern lifestyle; however, mining creates massive land disturbance and generates large quantities of unstable waste materials that need to be managed for the long-term environmental and public health of neighboring communities (Lima et al., 2016). One waste challenge associated with modern mining is managing mine tailings. Mine tailing reclamation is site specific but often has a long-term goal towards ecological restoration and is impacted by stakeholder and rights holder associations (i.e. private, government or tribal) (Keller et al, 2011). Mine waste reclamation aims to stabilize waste to support self-sustaining plant communities. A critical limitation to vegetation success in mining waste is that these “soils” are deficient of the microbial communities and nutrients necessary to support plant establishment. The costs associated with these restoration activities can also be substantial, and vary with mine size, regulatory regimes, technology, presence of legacy reclamation costs, or cultural resources within the area (Mudd, 2009). Long-term ecological management of mine waste is an essential and problematic component of efficient mine site reclamation throughout the Southwest. Soil health properties essential to successful phytostabilization of reclaimed mine sites are poorly understood. This study found that total nitrogen and DNA biomass show promise as potential indicators of soil fertility that correlate with revegetation improvement. Our studies suggest that capping material source significantly influences the rate of plant establishment. Quantitative metrics must be further investigated to improve methods for screening potential capping material sources for mine tailings reclamation. Longer term studies are needed, particularly for mine recovery in the Southwest, where plants grow slower. Future work should consider how below ground fertility metrics reflect ecosystem stability and plant structure, and how the quality and application method of soil capping may impact future plant community structure.