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Open Access Publications from the University of California

Scholarly Works (12 results)

  • Thesis
  • Peer Reviewed
UCLA Electronic Theses and Dissertations (2023)

The Quark Gluon Plasma (QGP), a state of matter in which deconfinement and chiral symmetry restoration occur, can be produced by ultra-relativistic heavy-ion collisions. This state of matter is of great interest because in QGP, the colored quarks and gluons, fundamental entities in matter whose interactions are governed by the Quantum ChromoDynamics (QCD), can exist as a fluid over an extended volume much larger than the size of nuclei. The Chiral Vortical Effect (CVE) is a QCD phenomenon related to the quark chirality arising from the topological sector of the QCD and the large vorticity of the QGP created. The search for quark chirality effects has been a major scientific objective at RHIC. \The Solenoid Tracker at RHIC (STAR) detector, located at the Relativistic Heavy-Ion Collider (RHIC) in the Brookhaven National Laboratory (BNL), provides the experimental capability needed to probe the QGP, with the particle tracking and identification abilities built into the different parts of the detector. This thesis focuses on the search for the CVE with STAR data from Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 27 GeV and 19.6 GeV, from Run 2018 and 2019, repsectively. \ In order to search for the CVE, measurements of the correlations of the azimuthal angles between baryons, $\Lambda$ and protons, were made, in the form of observables $\gamma_{112} \equiv \langle \cos(\phi_{\alpha} + \phi_{\beta} - 2\Psi_{RP}) \rangle$ and $\gamma_{132} \equiv \langle \cos(\phi_{\alpha} - 3\phi_{\beta} + 2\Psi_{RP}) \rangle$, in which mathematically the CVE effects would be made manifest. $\alpha$ and $\beta$ represent the charge of the correlated particles, and to reduce the background, we take $\Delta\gamma \equiv \gamma_{OS} - \gamma_{SS}$, where we subtract the measurement of the correlation of pairs of same charge particles (SS) from that of opposite charge particles (OS). The KFParticle package was used for the reconstruction of the $\Lambda$ particles. To have a better interpretation of the results, the observables $\kappa_{112} \equiv \Delta\gamma_{112} / (v_{2}\cdot\Delta\delta)$ and $\kappa_{132} \equiv \Delta\gamma_{132} / (v_{2}\cdot\Delta\delta)$ were computed that allows for comparison across different systems. Specifically, these observables were compared with data generated from the A Multi-Phase Transport Model (AMPT) simulations. \ In addition, the flow-related background was also something that needed to be dealt with to get a clearer signal from the $\Delta\gamma_{112}$ and $\Delta\gamma_{132}$ observables. The Event Shape Selection method was applied in order to project the events to zero flow, attempting to reduce the flow-related background as much as possible. The Event Plane Detector (EPD) event plane was used as well to reduce the non-flow backgrounds. \ Our search yielded no definitive observation of the proposed CVE signal. We obtained an upper limit on the CVE signal from Au+Au collisions at 19.6 GeV and 27 GeV energies. Because of large statistical errors due to limited number of $\Lambda$ per event, the obtained upper limit is not very stringent. We will also discuss a possible effect due to the presence of baryon annihilations and the future direction of CVE searches. Large statistical data sets will be critical for those efforts.

    Cover page: Search for the Chiral Vortical Effect Using Λ-p Correlations at STAR
    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2018)

    Background

    Electronic patient-portals offer the potential to enhance patient-physician communication and health outcomes but differential use may create or worsen disparities. While prior studies identified patient characteristics associated with patient-portal use, the role of physician factors is less known. We investigated differences in overall and patterns of portal use for patients with resident and attending primary care providers (PCPs).

    Methods

    Cross-sectional study of all established patients with a resident or attending PCP seen at an academic internal medicine practice (two sites) between May 1, 2014, and April 30, 2015. We defined patient-portal use as having accessed any "active" (secure messaging, medication refill request), or "passive" (viewing labs, after visit summaries, or appointments) patient-portal function more than once over the study period. We used generalized linear models clustered on PCP to examine the odds of patient-portal use by PCP type, adjusted for patient age, gender, preferred language, race/ethnicity, insurance, and visits. Among patient-portal users, we examined the association of PCP type with "active use" utilizing the same method.

    Results

    The mean patient age (n = 17,699) was 54.2 (SD 17.5), with 47.2% White, 23.6% Asian, 8.8% Black, 8.4% Latino, and 12% other/unknown. The majority (61.8%) had private insurance, and attending PCPs (76.9%). Although 72.3% enrolled in the patient-portal, only 53.4% were portal users; 40.0% were active users. There were 47 attending and 62 resident physicians. Patients with resident PCPs had lower odds of using the portal compared to those with attending PCPs (OR = 0.54, 95% CI 0.50-0.59). Similarly, among portal users, residents' patients had lower odds of being active users of the portal (OR = 0.76, 95% CI 0.68-0.87).

    Conclusion

    Given the lower patient-portal use among residents' patients, residency programs should develop curricula to bolster trainee competence in using the patient-portal for communication and to enhance the patient-physician relationship. Future research should explore additional physician factors that impact portal use.
      Cover page: A Comparison of Electronic Patient-Portal Use Among Patients with Resident and Attending Primary Care Providers
      • Article
      • Peer Reviewed
      UCSF Open Access Publishing Fund (2015)
        • Article
        • Peer Reviewed
        UC San Francisco Previously Published Works (2015)
          • Article
          • Peer Reviewed
          UC San Francisco Previously Published Works (2019)
          BACKGROUND: Early readmission amongst older safety-net hospitalized adults is costly. Interventions to prevent early readmission have had mixed success. The role of perceived social support is unclear. We examined the association of perceived social support in 30-day readmission or death in older adults admitted to a safety-net hospital. METHODS: This is an observational cohort study derived from the Support From Hospital to Home for Elders (SHHE) trial. Participants were community-dwelling English, Spanish and Chinese speaking older adults admitted to medicine wards at an urban safety-net hospital in San Francisco. We assessed perceived social support using the Multidimensional Scale of Perceived Social Support (MSPSS). We defined high social support as the highest quartile of MSPSS. We ascertained 30-day readmission and mortality based on a combination of participant self-report, hospital and death records. We used multiple/multivariable logistic regression to adjust for patient demographics, health status, and health behaviors. We tested for whether race/ethnicity modified the effect high social support had on 30-day readmission or death by including a race-social support interaction term. RESULTS: Participants (n = 674) had mean age of 66.2 (SD 9.0), with 18.8% White, 24.8% Black, 31.9% Asian, and 19.3% Latino. The 30-day readmission or death rate was 15.0%. Those with high social support had half the odds of readmission or death than those with low social support (OR = 0.47, 95% CI 0.26-0.88). Interaction analyses revealed race modified this association; higher social support was protective against readmission or death among minorities (AOR = 0.35, 95% CI 0.16-0.76) but increased likelihood of readmission or death among Whites (AOR = 3.7, 95% CI 1.07-12.9). CONCLUSION: In older safety-net patients nearing discharge, high perceived social support may protect against 30-day readmission or death among minorities. Assessing patients social support may aid targeting of transitional care resources and intervention design. How perceived social support functions across racial/ethnic groups in health outcomes warrants further study. TRIAL REGISTRATION: NIH trials registry number ClinicalTrials.gov: NCT01221532 .
            Cover page: High perceived social support and hospital readmissions in an older multi-ethnic, limited English proficiency, safety-net population.
            • Article
            • Peer Reviewed
            UC San Diego Previously Published Works (2023)
            INTRODUCTION: Latinas in the United States have higher mortality from breast cancer, but longitudinal studies of mammography ordering (a crucial initial step towards screening) in primary care are lacking. METHODS: We conducted an analysis of mammography order rates in Latinas (by language preference) and non-Latina white women (N = 181,755) over a > 10 year period in a multi-state network of community health centers (CHCs). We evaluated two outcomes (ever having a mammogram order and annual rate of mammography orders) using generalized estimating equation modeling. RESULTS: Approximately one-third of all patients had ever had a mammogram order. Among those receiving mammogram orders, English-preferring Latinas had lower mammogram order rates than non-Hispanic white women (RR = 0.92, 95% CI = 0.89-0.95). Spanish-preferring Latinas had higher odds of ever having a mammogram ordered than non-Hispanic whites (odds ratio = 2.12, 95% CI = 2.06-2.18) and, if ever ordered, had a higher rate of annual mammogram orders (rate ratio = 1.53, 95% CI = 1.50-1.56). CONCLUSION: These findings suggest that breast cancer detection barriers in low-income Latinas may not stem from a lack of orders in primary care, but in the subsequent accessibility of receiving ordered services.
              Cover page: The role of language in mammography orders among low-income Latinas over a 10-year period.
              • Article
              • Peer Reviewed
              UC Davis Previously Published Works (2017)

              Background

              Dysnatremias are associated with increased mortality in critically ill patients. Hypernatremia in burn patients is also associated with poor survival. Based on these findings, we hypothesized that high plasma sodium variability is a marker for increased mortality in severely burn-injured patients.

              Methods

              We performed a retrospective review of adult burn patients with a burn injury of 15% total body surface area (TBSA) or greater from 2010 to 2014. All patients included in the study had at least three serum sodium levels checked during admission. We used multivariate logistic regression analysis to determine if hypernatremia, hyponatremia, or sodium variability independently increased the odds ratio (OR) for death.

              Results

              Two hundred twelve patients met entry criteria. Mean age and %TBSA for the study was 45 ± 18 years and 32 ± 19%. Twenty-nine patients died for a mortality rate of 14%. Serum sodium was measured 10,310 times overall. The median number of serum sodium measurements per patient was 22. Non-survivors were older (59 ± 19 vs. 42 ± 16 years) and suffered from a more severe burn injury (50 ± 25% vs. 29 ± 16%TBSA). While mean sodium was significantly higher for non-survivors (138 ± 3 milliequivalents/liter (meq/l)) than for survivors (135 ± 2 meq/l), mean sodium levels remained within the laboratory reference range (135 to 145 meq/l) for both groups. Non-survivors had a significantly higher median number of hypernatremic (> 145 meq/l) measurements (2 vs. 0). Coefficient of variation (CV) was significantly higher in non-survivors (2.85 ± 1.1) than survivors (2.0 ± 0.7). Adjusting for TBSA, age, ventilator days, and intensive care unit (ICU) stay, a higher CV of sodium measurements was associated with mortality (OR 5.8 (95% confidence interval (CI) 1.5 to 22)). Additionally, large variation in sodium ranges in the first 10 days of admission may be associated with increased mortality (OR 1.35 (95% CI 1.06 to1.7)).

              Conclusions

              Increased variability in plasma sodium may be associated with death in severely burned patients.
                Cover page: Sodium variability is associated with increased mortality in severe burn injury.
                • Article
                • Peer Reviewed
                UC San Francisco Previously Published Works (2019)

                Background

                Early readmission amongst older safety-net hospitalized adults is costly. Interventions to prevent early readmission have had mixed success. The role of perceived social support is unclear. We examined the association of perceived social support in 30-day readmission or death in older adults admitted to a safety-net hospital.

                Methods

                This is an observational cohort study derived from the Support From Hospital to Home for Elders (SHHE) trial. Participants were community-dwelling English, Spanish and Chinese speaking older adults admitted to medicine wards at an urban safety-net hospital in San Francisco. We assessed perceived social support using the Multidimensional Scale of Perceived Social Support (MSPSS). We defined high social support as the highest quartile of MSPSS. We ascertained 30-day readmission and mortality based on a combination of participant self-report, hospital and death records. We used multiple/multivariable logistic regression to adjust for patient demographics, health status, and health behaviors. We tested for whether race/ethnicity modified the effect high social support had on 30-day readmission or death by including a race-social support interaction term.

                Results

                Participants (n = 674) had mean age of 66.2 (SD 9.0), with 18.8% White, 24.8% Black, 31.9% Asian, and 19.3% Latino. The 30-day readmission or death rate was 15.0%. Those with high social support had half the odds of readmission or death than those with low social support (OR = 0.47, 95% CI 0.26-0.88). Interaction analyses revealed race modified this association; higher social support was protective against readmission or death among minorities (AOR = 0.35, 95% CI 0.16-0.76) but increased likelihood of readmission or death among Whites (AOR = 3.7, 95% CI 1.07-12.9).

                Conclusion

                In older safety-net patients nearing discharge, high perceived social support may protect against 30-day readmission or death among minorities. Assessing patients' social support may aid targeting of transitional care resources and intervention design. How perceived social support functions across racial/ethnic groups in health outcomes warrants further study.

                Trial registration

                NIH trials registry number ClinicalTrials.gov: NCT01221532 .
                  • Article
                  • Peer Reviewed
                  UC San Francisco Previously Published Works (2015)

                  Background

                  The Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) and Care Transitions Measure (CTM-3) scores are patient experience measures used to determine hospital value-based purchasing reimbursement. Interventions to improve 30-day readmissions have met with mixed results, but less is known about their potential to improve the patient experience among older ethnically and linguistically diverse adults receiving care at safety-net hospitals. In this study, we assessed the effect of a nurse-led hospital-based care transition intervention on discharge-related patient experience in an older multilingual population of adults hospitalized at a safety-net hospital.

                  Methods

                  We randomized 700 inpatients aged 55 and older at an academic urban safety-net hospital. In addition to usual care, intervention participants received inpatient visits by a language-concordant study nurse and post-discharge phone calls from a language-concordant nurse practitioner to reinforce the care plan and to address acute complaints. We measured HCAHPS nursing, medication, and discharge communication domain scores and CTM-3 scores at 30 days after hospital discharge.

                  Results

                  Of 685 participants who survived to 30 days, 90 % (n = 616) completed follow-up interviews. The mean age was 66.2 years; over half (54.2 %) of the participants had cognitive impairment, and 33.8 % had moderate to severe depression. The majority (62.1 %) of interviews were conducted in English; 23.3 % were conducted in Chinese and 14.6 % in Spanish. Study nurses spent an average of 157 min with intervention participants. Between intervention and usual care participants, CTM-3 scores (80.5 % vs 78.5 %; p = 0.18) and HCAHPS discharge communication domain scores (74.8 % vs 68.7 %; p = 0.11) did not differ, nor did HCAHPS scores in medication (44.5 % vs 53.1 %; p = 0.13) and nursing domains (67.9 % vs 64.9 %; p = 0.43). When stratified by language, no significant differences were seen.

                  Conclusion

                  An inpatient standalone transition-of-care intervention did not improve patient discharge experience. Older multi-lingual and cognitively impaired populations may require higher-intensity interventions post-hospitalization to improve discharge experience outcomes.
                    • Article
                    • Peer Reviewed
                    UC San Francisco Previously Published Works (2015)
                    Little is known about trends in depression at antiretroviral therapy (ART) initiation among people living with HIV (PLHIV) in low- and middle-income countries. We used data from an ongoing cohort of treatment-naïve PLHIV in rural Uganda to estimate secular trends in depression among PLHIV at ART initiation. We fitted linear regression models with depression symptom severity as the outcome variable and year of cohort entry (2005-2012) as the explanatory variable, adjusting for socio-demographic variables and assessing physical health score, body mass index (BMI), and CD4 count as potential mediators of a secular trend in depression symptom severity. There was a statistically significant negative association between year of entry and depression symptom severity, suggesting a 3.1 % relative decline in the mean depression symptom severity score at ART initiation in each year of study recruitment after the first year. This trend remained statistically significant after inclusion of baseline socio-demographic characteristics to the model and appeared to be driven by improved physical health scores, but not CD4 count or BMI.
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