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Open Access Publications from the University of California

Scholarly Works (20 results)

  • Thesis
  • Peer Reviewed
UC San Diego Electronic Theses and Dissertations (2022)

Computer Science is one of the most rapidly expanding career fields and high schools across the country have responded by increasing access to programming courses by over 300% in the last decade (College Board, 2020a; College Board, 2020b; U.S. Bureau of Labor Statistics, 2020). However, as job openings and course access increase, racial and gender gaps within tech industries continue to present an array of problems that range from stifled creativity to racially biased software (Bobb, 2016; Hoever, Van Knippenberg, Van Ginkel, & Barkema, 2012; Lee, 2018; Rock & Grant, 2019; Sandvig, 2016; Stevens, 2008; U.S. Bureau of Labor Statistics, 2020). Thus, as access to Computer Science in secondary schools increases, so must educator understanding of how to support underrepresented students within these courses.

Collaboration is widely recognized as an instructional strategy that supports both social emotional and academic success. However, the specific role this strategy plays in CS classes has primarily been explored through quantitative research efforts with minimal focus on the lived experiences and perspectives of these underrepresented students. The research presented in this dissertation contributes to this growing understanding by using a primarily qualitative lens to examine the impact that structured collaboration has on the experiences of underrepresented students in high school CS courses. Building upon existing research, this study provides additional support for the use of accountability structures as a means of transforming peer interaction into Cooperative Learning. By amplifying the voices of Black, Latinx, and female students within high school CS classes, this study provides a better understanding of how instructional strategies can be leveraged to support these students.

The results of this research capture the strengths and shortfalls that students perceive when engaging in Cooperative Learning activities. Key findings include student concern over how effort and voice are distributed during collaboration, individual increases in content confidence and creativity attested to the exchange of ideas, and an intrinsic need to feel connected and comfortable with their peers. Through these perceived relationships between collaboration, academic growth, and social emotional well-being, this study highlights several opportunities for educators to better engage and support underrepresented students within high school CS courses.

    Cover page: Cooperative Coding: How Underrepresented Students Perceive Collaboration in Computer Science
    • Article
    • Peer Reviewed
    LBL Publications (2018)
    Carbon capture (CC) technology is receiving increasing attention as a critical technology for climate change mitigation. Most previous studies focus on the application of CC technology in the power generation sector, while fewer studies have analyzed applications in the refining industry, which is one of the largest greenhouse gas (GHG) emissions sources in the U.S. industrial sector. Unlike the power generation sector, the refining industry has highly distributed CO2 emission sources. In this paper, bottom-up modeling and techno-economic analysis approaches are integrated to quantify the national CO2 emission reduction potential and costs of three types of CC technologies applied to U.S. refineries: (1) pre-combustion, (2) post-combustion, and (3) oxyfuel-combustion. Two scenarios are developed to compare different design strategies for CC systems; one is a distributed design scenario for post-combustion technology, the other is a centralized design scenario for pre-combustion and oxyfuel-combustion technology. The results of the two scenarios are compared, and the trade-offs between different design strategies are highlighted. The results shown in this study provide an intuitive and quantitative understanding of the potential of CC technology to reduce CO2 emissions from the U.S. refining industry. Such information is helpful to policymakers, oil companies, and energy/environmental analysts for strategic planning and systems design to manage future CO2 emissions of refineries.
      Cover page: Quantifying carbon capture potential and cost of carbon capture technology application in the U.S. refining industry
      • Article
      • Peer Reviewed
      Dermatology Online Journal, Volume 29, Issue 2 (2023)
      Dermatomyositis is an inflammatory myopathy involving the skin that typically affects patients between 40-60 years of age and is more likely to be diagnosed in women. Around 10-20% of dermatomyositis cases present with subclinical or absent muscle involvement, termed "clinically amyopathic." Presence of anti-transcription intermediary factor 1? (TIF1?) antibodies is an important indicator of underlying malignancy. We present a patient with anti-TIF1? positive amyopathic dermatomyositis associated with bilateral breast cancer. The patient was safely treated with trastuzumab for breast cancer and intravenous immunoglobulin for dermatomyositis.
        Cover page: Amyopathic dermatomyositis with TIF1? positivity treated with IVIGCreative Commons 'BY-NC-ND' version 4.0 license
        • Article
        • Peer Reviewed
        Dermatology Online Journal, Volume 24, Issue 9 (2018)
        Primary cutaneous amyloidosis may be characterized as macular amyloidosis, lichenoid amyloidosis, or nodular amyloidosis. Nodular amyloidosis results from the deposition of immunoglobulin light chains and may rarely be associated with systemic amyloidosis. We report an unusual case of a patient with systemic scleroderma who developed primary cutaneous nodular amyloidosis on the left lower leg. The diagnosis was confirmed with a skin biopsy with Congo red staining and a novel technique using a laser microdissection and mass spectrometry-based proteomic analysis method for amyloid protein characterization. A work-up for systemic amyloidosis was negative and the patient improved symptomatically with wound care. Patients with primary cutaneous nodular amyloidosis should be followed clinically over time for the possible development of systemic amyloidosis, although the risk of disease progression is likely low.
          Cover page: Nodular amyloidosis in a patient with systemic sclerodermaCreative Commons 'BY-NC-ND' version 4.0 license
          • Article
          • Peer Reviewed
          UC Davis Previously Published Works (2020)

          Background

          The United Nations Refugee Agency (UNHCR) estimates the number of forcibly displaced people increased from 22.7 million people in 1996 to 67.7 million people in 2016. Human mobility is associated with the introduction of infectious disease pathogens. The aim of this study was to describe the range of pathogens in forcibly displaced populations over time using an informal event monitoring system.

          Methods

          We conducted a retrospective analysis of ProMED, a digital disease monitoring system, to identify reports of outbreak events involving forcibly displaced populations between 1996 and 2016. Number of outbreak events per year was tabulated. Each record was assessed to determine outbreak location, pathogen, origin of persons implicated in the outbreak, and suspected versus confirmed case counts.

          Results

          One hundred twenty-eight independent outbreak events involving forcibly displaced populations were identified. Over 840,000 confirmed or suspected cases of infectious diseases such as measles, cholera, cutaneous leishmaniasis, dengue, and others were reported in 48 destination countries/territories. The average rate of outbreak events concerning forcibly displaced persons per total number of reports published on ProMED per year increased over time. The majority of outbreak events (63%) were due to acquisition of disease in the destination country.

          Conclusion

          This study found that reports of outbreak events involving forcibly displaced populations have increased in ProMED. The events and outbreaks detected in this retrospective review underscore the importance of capturing displaced populations in surveillance systems for rapid detection and response.
            Cover page: Infectious disease outbreaks among forcibly displaced persons: an analysis of ProMED reports 1996-2016.
            • Article
            • Peer Reviewed
            LBL Publications (2015)
            The U.S. EPA is in the final stages of promulgating regulations to reduce CO2 emissions from the electricity generating industry. A major component of EPA's regulatory strategy targets improvements to power plant operating efficiencies. As the EPA expands regulatory requirements to other industries, including petroleum refining, it is likely that plant efficiency improvements will be critical to achieving CO2 emission reductions. This paper identifies efficiency improvement measures applicable to refining, and quantifies potential cost of conserved energy for these measures. Analysis is at the U.S. petroleum refining sector national-level employing an aggregated notional refinery model (NRM), with the aim of estimating the efficacy of efficiency improvements for reducing emissions. Using this method, roughly 1500 petajoules per year (PJ/yr) of plant fuel savings and 650 gigawatt-hour per year (GWh/yr) of electricity savings (representing 54% and 2% of U.S. refining industry consumption, respectively) are potentially cost-effective. This equates to a potential 85 Mt-CO2/yr reduction. An additional 458 PJ/yr fuel reduction and close to 2750 GWh/yr of electricity reduction (27 Mt-CO2/yr) are not cost-effective at prevailing natural gas market prices. Results are presented as a supply-curve ordering measures from low to high cost of fuel savings versus cumulative energy reduction.
            • 1 supplemental PDF
            Cover page: Efficiency improvement and CO2 emission reduction potentials in the United States petroleum refining industry
            • Article
            • Peer Reviewed
            Dermatology Online Journal, Volume 27, Issue 6 (2021)
            Syphilis has many atypical morphologies which can present a diagnostic challenge, especially in patients with HIV/AIDS who may have multiple concurrent conditions. We describe a 41-year-old man with recently diagnosed HIV who was admitted for acute right vision loss and a diffuse rash with involvement of the palms and soles. He received diagnoses of secondary syphilis and Kaposi sarcoma in the setting of AIDS. Examination revealed an unusual dark brown-to-purple umbilicated papule with a necrotic center on the abdomen, raising a diagnostic dilemma. Skin biopsy showed secondary syphilis, despite the concurrent diagnosis of Kaposi sarcoma. The patient was treated with antibiotic and antiretroviral therapy and symptoms resolved. This case aims to share the clinical reasoning behind diagnosing a patient with HIV/AIDS with multiple concurrent conditions and to raise awareness of the many atypical cutaneous manifestations of secondary syphilis.
              Cover page: An abdominal skin lesion: to lump or split? a case presentationCreative Commons 'BY-NC-ND' version 4.0 license
              • Article
              • Peer Reviewed
              UC Irvine Previously Published Works (2021)

              Background

              Cardiovascular and other circulatory system diseases have been implicated in the severity of COVID-19 in adults. This study provides a super learner ensemble of models for predicting COVID-19 severity among these patients.

              Method

              The COVID-19 Dataset of the Cerner Real-World Data was used for this study. Data on adult patients (18 years or older) with cardiovascular diseases between 2017 and 2019 were retrieved and a total of 13 of these conditions were identified. Among these patients, 33,042 admitted with positive diagnoses for COVID-19 between March 2020 and June 2020 (from 59 hospitals) were identified and selected for this study. A total of 14 statistical and machine learning models were developed and combined into a more powerful super learning model for predicting COVID-19 severity on admission to the hospital.

              Result

              LASSO regression, a full extreme gradient boosting model with tree depth of 2, and a full logistic regression model were the most predictive with cross-validated AUROCs of 0.7964, 0.7961, and 0.7958 respectively. The resulting super learner ensemble model had a cross validated AUROC of 0.8006 (range: 0.7814, 0.8163). The unbiased AUROC of the super learner model on an independent test set was 0.8057 (95% CI: 0.7954, 0.8159).

              Conclusion

              Highly predictive models can be built to predict COVID-19 severity of patients with cardiovascular and other circulatory conditions. Super learning ensembles will improve individual and classical ensemble models significantly.
                Cover page: A super learner ensemble of 14 statistical learning models for predicting COVID-19 severity among patients with cardiovascular conditions
                • Article
                • Peer Reviewed
                UC San Francisco Previously Published Works (2021)

                Purpose

                Prior studies reporting efficacy of radiofrequency catheter ablation for complex ventricular ectopy in mitral valve prolapse (MVP) are limited by selective inclusion of bileaflet MVP, papillary muscle only ablation, or short-term follow-up. We sought to evaluate the long-term incidence of hemodynamically significant ventricular tachycardia (VT) or fibrillation (VF) in patients with MVP after initial ablation.

                Methods

                We studied consecutive patients with MVP undergoing ablation for complex ventricular ectopy between 2013 and 2017 at our institution. Of 580 patients with MVP, we included 15 (2.6%, 10 women; mean age 50 ± 14 years, 53% bileaflet) with complex ventricular ectopy treated with initial ablation.

                Results

                Over a median follow-up of 3406 (1875-6551) days or 9 years, 5 of 15 (33%) patients developed hemodynamically significant VT/VF after their initial ablation and underwent placement of an implantable cardioverter defibrillator (ICD). Three of 5 also underwent repeat ablations. Sustained VT was inducible prior to index ablation in all 5 who developed VT/VF, compared to none of the 10 patients who did not develop VT/VF after index ablation (p = 0.002). Complex ventricular ectopy at index ablation was multifocal in all 5 patients who underwent repeat intervention versus 4 of 10 patients (40%) who did not (p = 0.04). All 3 patients with subsequent VT/VF who underwent repeat ablation had a new clinically dominant focus of ventricular arrhythmia and 3 of the patients with ICD had appropriate VT/VF therapies.

                Conclusions

                In the long term, a subset of MVP patients treated with ablation for ventricular arrhythmias, all with multifocal ectopy on initial EP study, develop hemodynamically significant VT/VF. Our findings suggest the progressive nature of ventricular arrhythmias in patients with MVP and multifocal ectopy.
                  Cover page: Long-term outcomes of ablation for ventricular arrhythmias in mitral valve prolapse.
                  • Article
                  • Peer Reviewed
                  UC San Diego Previously Published Works (2015)

                  Introduction

                  Plasma levels of amyloid-beta (Aβ) do not correlate well with different stages of Alzheimer's disease (AD) in cross-sectional studies. Measuring the changes in Aβ plasma levels with an acute intervention may be more sensitive to distinguishing individuals in earlier stages of AD (mild cognitive impairment; MCI) from normal controls.

                  Methods

                  57 participants (18 with AD/MCI and 39 cognitively normal controls) underwent oral glucose tolerance testing (OGTT). Blood samples were obtained over a 2 hour time period. Changes in plasma Aβ40 and42 levels were measured from either baseline or 5 minutes to the 10 minute time point.

                  Results

                  Compared to normal controls, subjects with AD/MCI had significantly less change (Δ) in plasma levels for both Aβ40(-3.13(40.93)pg/ml vs. 41.34(57.16)pg/ml;p=0.002) and Aβ42(-0.15(3.77)pg/ml vs. 5.64(10.65)pg/ml; p=0.004).

                  Discussion

                  OGTT combined with measures of plasma Aβ40 and 42 is potentially useful in distinguishing aging individuals who are in different stages of AD.
                    Cover page: Oral glucose tolerance testing to modulate plasma amyloid levels: A novel biomarker
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