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Open Access Publications from the University of California

Scholarly Works (17 results)

  • Thesis
  • Peer Reviewed
UC San Diego Electronic Theses and Dissertations (2025)

Advances in optical and near-infrared (NIR) instrumentation for astronomy, from modest early telescopes to today’s cryogenically cooled instruments on 10-meter-class observatories, have continually expanded our understanding of the universe. Modern systems now combine large primary mirrors, adaptive optics (AO) to correct for atmospheric distortion, and integral field spectrographs (IFS) that provide spatially resolved spectra. Together, these technologies enable transformative capabilities across a wide range of science cases.

This thesis presents the design and development of Liger, a second-generation AO-fed IFS for the W. M. Keck Observatory. Liger builds on the design of the InfraRed Imaging Spectrograph (IRIS), the first-light instrument for the Thirty Meter Telescope (TMT), and adapts it for Keck using new re-imaging optics and a custom-designed imager. I detail the mechanical design of the imager subsystem, including the characterization chamber, baffling, kinematic mounting system, pupil-viewing camera, and detector mount. The design is validated through structural analysis using SolidWorks Simulation, and I report on fabrication progress and plans for future characterization.

A key innovation of the Liger imager is a mounting system that positions pick-off mirrors directly above the detector to redirect light from the imager focal plane to the spectrograph. This enables simultaneous imaging and integral field spectroscopy, allowing for advanced techniques such as using imager-derived point spread function (PSF) data to improve IFS data reduction.

In addition to hardware, I developed end-to-end data simulation software to predict Liger’s sensitivity to both point and extended sources, benchmarking performance against other world-class observatories. I present sensitivity estimates for the imager and all IFS modes using point sources, and validate results by comparing simulated outputs to real observations of resolved sources. I also discuss how variations in PSF parameters affect measurements of galaxy properties such as the Sérsic index.

This work advances the design and scientific capabilities of AO-fed IFS instruments. Liger lays a foundation for future innovations on current 8–10 meter-class telescopes and the next generation of 30-meter-class observatories. My contributions to instrument design and modeling support more precise, efficient, and far-reaching high-resolution astrophysics.

    • Article
    • Peer Reviewed
    UC San Francisco Previously Published Works (2013)

    Background

    The patient-centered medical home (PCMH) is a key service delivery innovation in health reform. However, there are growing questions about whether the changes in clinics promoted by the PCMH model lead to improvements in the patient experience.

    Objective

    To test the hypothesis that PCMH improvements in safety-net primary care clinics are associated with a more positive patient experience.

    Research design

    Multilevel cross-sectional analysis of patients nested within the primary care clinics that serve them.

    Subjects

    Primary care clinic leaders and patients throughout the City of New Orleans health care safety-net.

    Measures

    Dependent variables included patient ratings of accessibility, coordination, and confidence in the quality/safety of care. The key independent variable was a score measuring PCMH structural and process improvements at the clinic level.

    Results

    Approximately two thirds of patients in New Orleans gave positive ratings to their clinics on access and quality/safety, but only one third did for care coordination. In all but the largest clinics, patient experiences of care coordination were positively associated with the clinic's use of PCMH structural and process changes. Results for patient ratings of access and quality/safety were mixed.

    Conclusions

    Among primary care clinics in the New Orleans safety-net, use of more PCMH improvements at the clinic level led to more positive patient rating of care coordination, but not of accessibility or confidence in quality/safety. Ongoing efforts to pilot, demonstrate, implement, and evaluate the PCMH should consider how the impact of medical practice transformation could vary across different aspects of the patient experience.
      Cover page: Transforming Primary Care in the New Orleans Safety-net
      • Article
      • Peer Reviewed
      UC San Francisco Previously Published Works (2012)
      Hurricane Katrina destroyed much of the health care infrastructure in and around New Orleans in 2005. We describe a natural experiment that occurred afterward, amid efforts to rebuild the city's health care system, in which diverse safety-net clinics were transformed into medical homes. Using surveys of clinic leaders and administrative data, we found that clinics made substantial progress in implementing new clinical processes to improve access, quality and safety, and care coordination and integration. But there was wide variation, with some clinics making only minimal progress. Because the transformation was closely tied to the receipt of federal grants and bonus payments, we observed declines in performance toward the end of the study, when clinics faced diminished federal funding and refocused their priorities on survival. Now that federal funds have dried up, moreover, clinics may be losing ground in sustaining their practice changes. The experience shows that payment to support medical home transformation must be robust and stable, and clinics need to be fully integrated into the broader health care system to improve overall coordination of care.
        Cover page: The Post-Katrina Conversion Of Clinics In New Orleans To Medical Homes Shows Change Is Possible, But Hard To Sustain
        • Article
        • Peer Reviewed
        UC San Francisco Previously Published Works (2014)

        Objective

        To evaluate safety-net clinics' responses to a novel community-wide Patient-Centered Medical Home (PCMH) financial incentive program in post-Katrina New Orleans.

        Data sources/study setting

        Between June 2008 and June 2010, we studied 50 primary care clinics in New Orleans receiving federal funds to expand services and improve care delivery.

        Study design

        Multiwave, longitudinal, observational study of a local safety-net primary care system.

        Data collection

        Clinic-level data from a semiannual survey of clinic leaders (89.3 percent response rate), augmented by administrative records.

        Principal findings

        Overall, 62 percent of the clinics responded to financial incentives by achieving PCMH recognition from the National Committee on Quality Assurance (NCQA). Higher patient volume, higher baseline PCMH scores, and type of ownership were significant predictors of achieving NCQA recognition. The steepest increase in adoption of PCMH processes occurred among clinics achieving the highest, Level 3, NCQA recognition. Following NCQA recognition, 88.9 percent stabilized or increased their use of PCMH processes, although several specific PCMH processes had very low rates of adoption overall.

        Conclusions

        Findings demonstrate that widespread PCMH implementation is possible in a safety-net environment when external financial incentives are aligned with the goal of practice innovation.
          Cover page: Incentivizing Primary Care Providers to Innovate: Building Medical Homes in the Post‐Katrina New Orleans Safety Net
          • Article
          • Peer Reviewed
          UC San Francisco Previously Published Works (2013)

          Purpose

          We sought to compare and contrast patterns of change toward patient-centered medical homes (PCMHs) in 5 New Orleans primary care safety net clinics in the aftermath of Hurricane Katrina. We assessed the general direction of change in practice to discover possible reasons for differences in patterns of change, and to identify impediments to change.

          Methods

          Data collection consisted of 5 semiannual telephone interviews with clinic leadership over 2.5 years supplemented by administrative audits. We used standard survey indexes of PCMH to monitor practice change. We conducted site visits and unstructured in-person interviews with clinicians and staff of the 5 clinics.

          Results

          PCMH index scores improved during the observation period with variations in rates of change and initial levels of PCMH. Qualitative analysis suggested possible explanations for this differential success: (1) early vs later starts in practice change, (2) funding based on patient outcomes, (3) demands that compete with practice change, (4) qualities of clinic leadership, and (5) relations with the communities where patients live. Barriers to practice change included high demand for services, deficient linkages between hospital and specialty care, lack of staff resources, and a need to focus on clinic finances.

          Conclusions

          The PCMH model can successfully address the needs of safety net populations. Stable leadership committed to serving safety net patients via the PCMH model is important for successful practice transformation. Beyond clinic walls, cultivating deep ties to the communities that clinics serve also supports the PCMH model.
            Cover page: Contrasting trajectories of change in primary care clinics: lessons from New Orleans safety net.
            • Article
            • Peer Reviewed
            UC San Francisco Previously Published Works (2018)

            Background

            In China, about 53.4 million women (11%) have type 2 diabetes (T2DM). Women with prior 2 (GDM) are at a high risk for T2DM. Postpartum lifestyle interventions have been effective in reducing T2DM for this population, but the evidence is limited to interventions provided in urban areas, despite the fact that a higher prevalence of undiagnosed T2DM was found in rural areas in China. The primary purpose of this proposed study is to examine the effect of a postpartum intensive lifestyle modification (ILSM) program on physiological health outcomes (T2DM development, insulin resistance, and weight-related variables), weight-related health behaviors (dietary intake and physical activity), and psychosocial outcomes (self-efficacy, perceived stress, social support, and health-related quality of life) compared to usual care at 3, 6, and 18 months post baseline assessment. The secondary outcomes are to identify potential mediators and moderators on change of physiological health outcomes.

            Methods/design

            A multi-site randomized clinical trial (RCT) will be conducted to examine the efficacy of an evidence-based Intensive Lifestyle Modification (ILSM) program compared with usual care for women with prior GDM living in rural areas in China. A total sample of 256 participants will be recruited in the study. The intervention consists of six bi-weekly in-person group sessions, five bi-weekly telephone consultation sessions, and three monthly telephone consultations to encourage behavior change. The usual care provided to the control group will utilize current clinical guideline and recommendations for T2DM prevention. Outcome measures include physiological variables (OGTT-2 h, HbA1c, weight, and waist circumference); weight-related health behavioral (dietary intake and physical activities); and psychosocial variables (self-efficacy and social support) at 3-, 6- and 18- month after baseline. We will also assess the potential cost-effectiveness of ILSM (net cost per T2DM case and per DALY averted) compared with usual care.

            Discussion

            If successful, this ILSM program can be adapted and used in rural areas as a blueprint for clinical guidelines to decrease T2DM by improving postpartum GDM care in China. Findings of this study are expected to make a significant contribution to public health practice and health policy related to T2DM prevention in China.

            Trial registration

            Chinese Clinical Trial Registry, ChiCTR1800015023 . Registered 1 March 2018 - Retrospectively registered, http://apps.who.int/trialsearch/default.aspx .
              Cover page: Effectiveness of a diabetes prevention program for rural women with prior gestational diabetes mellitus: study protocol of a multi-site randomized clinical trial
              • Article
              • Peer Reviewed
              UC San Francisco Previously Published Works (2018)

              Background

              In China, about 53.4 million women (11%) have type 2 diabetes (T2DM). Women with prior 2 (GDM) are at a high risk for T2DM. Postpartum lifestyle interventions have been effective in reducing T2DM for this population, but the evidence is limited to interventions provided in urban areas, despite the fact that a higher prevalence of undiagnosed T2DM was found in rural areas in China. The primary purpose of this proposed study is to examine the effect of a postpartum intensive lifestyle modification (ILSM) program on physiological health outcomes (T2DM development, insulin resistance, and weight-related variables), weight-related health behaviors (dietary intake and physical activity), and psychosocial outcomes (self-efficacy, perceived stress, social support, and health-related quality of life) compared to usual care at 3, 6, and 18 months post baseline assessment. The secondary outcomes are to identify potential mediators and moderators on change of physiological health outcomes.

              Methods/design

              A multi-site randomized clinical trial (RCT) will be conducted to examine the efficacy of an evidence-based Intensive Lifestyle Modification (ILSM) program compared with usual care for women with prior GDM living in rural areas in China. A total sample of 256 participants will be recruited in the study. The intervention consists of six bi-weekly in-person group sessions, five bi-weekly telephone consultation sessions, and three monthly telephone consultations to encourage behavior change. The usual care provided to the control group will utilize current clinical guideline and recommendations for T2DM prevention. Outcome measures include physiological variables (OGTT-2 h, HbA1c, weight, and waist circumference); weight-related health behavioral (dietary intake and physical activities); and psychosocial variables (self-efficacy and social support) at 3-, 6- and 18- month after baseline. We will also assess the potential cost-effectiveness of ILSM (net cost per T2DM case and per DALY averted) compared with usual care.

              Discussion

              If successful, this ILSM program can be adapted and used in rural areas as a blueprint for clinical guidelines to decrease T2DM by improving postpartum GDM care in China. Findings of this study are expected to make a significant contribution to public health practice and health policy related to T2DM prevention in China.

              Trial registration

              Chinese Clinical Trial Registry, ChiCTR1800015023 . Registered 1 March 2018 - Retrospectively registered, http://apps.who.int/trialsearch/default.aspx .
                Cover page: Effectiveness of a diabetes prevention program for rural women with prior gestational diabetes mellitus: study protocol of a multi-site randomized clinical trial.
                • Article
                • Peer Reviewed
                UC San Francisco Previously Published Works (2021)
                To explore the association between perceived stress and quality of life (QoL) and the mediating role of general self-efficacy and social support in this association. Gestational diabetes mellitus (GDM) is one of the most common metabolic diseases suffered by pregnant women. Women with previous GDM may experience more medical-related stress and have a lower QoL than those without it. A multisite correlational study. Four hundred sixty-five women with previous GDM living in rural areas in China participated in this study from November 2017 to June 2019. The participants completed a set of self-reported socio-demographic questionnaires, the Perceived Stress Scale, the General Self-Efficacy Scale, the Social Support Rating Scale and the World Health Organization QoL assessment (Brief version). STROBE checklist was used as the guideline for this study. The mean QoL score was 13.97 (SD 2.07) for physical health, 13.75 (SD 1.98) for psychological health, 14.96 (SD 1.99) for social relations and 12.49 (SD 1.74) for environmental conditions. About 43.9% of women with previous GDM reported increased stress, which was negatively correlated with each of these QoL domains. Yet, the negative effect of perceived stress on QoL could be completely or partly mediated by better social support or general self-efficacy among this population. Nearly half of the women in the study living in rural China reported increased stress after delivery, and there is room to improve QoL in the environmental domain among women with previous GDM. Increasing general self-efficacy or social support can help these women avoid the negative effects of perceived stress on their QoL. These findings suggest that healthcare providers need to be cognizant of the importance of self-efficacy and social support for women with previous GDM in both enhancing QoL and reducing the negative impact of perceived stress on QoL.
                  • Article
                  • Peer Reviewed
                  UC San Francisco Previously Published Works (2021)
                  Women with prior gestational diabetes mellitus (GDM) are at a higher risk of type 2 diabetes and other health issues after delivery. They may have a lower quality of life (QoL), experience more medical-related stress, and need more support than those without it. This study aimed to examine the six-month efficacy of an intensive lifestyle modification program on perceived stress, social support, and QoL among women with prior GDM in rural China. A total of 320 women with prior GDM were randomly assigned to an intervention group (n = 160) and a control group (n = 160). Participants in the intervention group received an intensive lifestyle modification (ILSM) program, including a series of six biweekly face-to-face sessions and five biweekly phone sessions delivered by trained local health workers. The control group received the usual care. Data about perceived stress, social support, QoL, and HbA1c were collected at baseline, at three months, and at six-month follow-ups. Generalized estimating equation analysis was used to assess the efficacy of the intervention. There were significant improvements in the psychological domain (β = 0.479 ± 0.153, p = 0.002) and environmental domain (β = 0.462 ± 0.145, p = 0.001) of QoL over six months; there were significant group effects (β = -0.718 ± 0.280, p = 0.010) and time effects (β = 0.453 ± 0.211, p = 0.032) in physiological domain, and there were significant group effects in the social relations domain (β = -0.669 ± 0.321, p = 0.037). The ILSM group had a more pronounced downward trend in HbA1c than the control group (β = -0.050 ± 0.026, p = 0.059). The ILSM program can help women with GDM improve their psychological and environmental domain of QoL. It can be recommended as a form of health promotion for improving QoL among women with prior GDM in rural primary care settings in developing countries.
                    Cover page: The Efficacy of an Intensive Lifestyle Modification Program on Psychosocial Outcomes among Rural Women with Prior Gestational Diabetes Mellitus: Six Months Follow-Up of a Randomized Controlled Trial
                    • Article
                    • Peer Reviewed
                    UC San Francisco Previously Published Works (2017)
                    BACKGROUND: A community-based organization implemented an evidence-based intervention to help rural cancer patients list questions before oncology visits. OBJECTIVE: Was the question-listing intervention effective in reducing anxiety and increasing decision self-efficacy? METHODS: The organization surveyed patients on decision self-efficacy (273 respondents, 99% response rate) and anxiety (190, 68%) before and after question-listing interventions delivered from 2006 - 2011. We analyzed responses using two-sided paired t-tests at 5% significance and conducted linear regression to identify significant predictors of change. We examined predictors related to the patient (location, demographics, disease status and baseline decision self-efficacy and anxiety); the intervention (including interventionist case volume); and the visit (including type of doctor seen). RESULTS: Question-listing was associated with higher mean decision self-efficacy (2.70/3.43 pre/post, 1-4 min-max, P<.001) and lower mean anxiety (7.26/5.87, 1-10 min-max, P<.001). Significant predictors of change in decision self-efficacy included: patient location; interventionist case volume; baseline decision self-efficacy and anxiety. Higher baseline anxiety was also associated with reductions in anxiety. CONCLUSIONS: In a sustained community-based implementation, the intervention helped patients prepare for oncology visits. Patients reported higher self-efficacy and lower anxiety.
                      Cover page: The Effects of Coaching Patients to List Questions Before Visiting Cancer Specialists: Retrospective Evaluation of Visit Preparation in a Rural, Underserved Setting.
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