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Open Access Publications from the University of California

Scholarly Works (19 results)

  • Article
  • Peer Reviewed
UC Santa Barbara Previously Published Works (2015)
We extend the canonical cell decomposition due to Epstein and Penner of a hyperbolic manifold with cusps to the strictly convex setting.
    Cover page: A generalization of the Epstein-Penner construction to projective manifolds
    • Article
    • Peer Reviewed
    UC Irvine Previously Published Works (2012)

    Objectives

    Associations of emergency department (ED) visits and hospital admissions for asthma in children with demographics and area socio-economic status (SES) were examined to evaluate long-term trends and identify vulnerable populations.

    Study design

    Retrospective population-based trend and cross-sectional analyses.

    Methods

    Asthma hospital admissions (2000-2007) and ED visits (2005-2007) for children aged 0-14 years living in Orange County, California were linked with zip-code-level SES data (2000 US Census). Annual population estimates were obtained to calculate age-specific admissions and ED visit rates. Average annual percentage changes (AAPC) were calculated with joinpoint analyses. The risks of ED visits and hospital admissions were estimated from SES indicators with negative binomial regression.

    Results

    Rates of asthma hospital admissions and ED visits were highest among children aged 0-4 years, males and African Americans, and lowest among Asian/Pacific Islanders. African Americans and Hispanics/Latinos were more likely to be uninsured. Asthma admissions decreased significantly for all age groups over the study period. The greatest declines per 100,000 were among children aged 0-4 years (AAPC: -15.3%, 95% confidence interval -17.0% to -13.4%). Rates of hospital admissions and ED visits were significantly higher in low-SES groups. Hospital admission rates were 30-60% higher and ED visits were 80-90% higher in zip codes in the lowest tertile of median household income compared with the highest tertile of median household income.

    Conclusions

    Paediatric asthma hospitalizations and ED visit rates are declining in Orange County. However, certain groups are disproportionately affected, including those living in areas with low SES. This information will help in targeting intervention strategies to children at highest risk for severe asthma episodes.
      Cover page: Paediatric asthma hospital utilization varies by demographic factors and area socio-economic statusCreative Commons 'BY' version 4.0 license
      • Article
      Western Journal of Emergency Medicine: Integrating Emergency Care with Population Health, Volume 16, Issue 4.1 (2015)
        Cover page: Mapping Emergency Medicine Milestones to an Existing Simulation CurriculumCreative Commons 'BY' version 4.0 license
        • Article
        • Peer Reviewed
        ICTS Publications (2005)
          Cover page: IL-6-induced skeletal muscle atrophyCreative Commons 'BY' version 4.0 license
          • Article
          • Peer Reviewed
          UC Irvine Previously Published Works (2009)

          Objective

          The prevalence of adverse respiratory outcomes among children has been frequently associated with measurements of traffic-related exposures, and other data suggest asthma severity is worsened with residence near heavy traffic. We examined the association between neighbourhood traffic burden and repeated acute respiratory illnesses that required emergency department visits and/or hospitalisation for children with a primary or secondary diagnosis of asthma (89% acute bronchitis or pneumonia).

          Methods

          This is a hospital-based longitudinal study of a southern California urban catchment area around two adjacent children's hospitals. Subjects' home addresses were geocoded and linked to nearby traffic data. Recurrent event proportional hazard analysis was used to estimate the hazard of repeated hospital encounters.

          Results

          We found living within 300 metres of arterial roads or freeways increased risk of repeated hospital encounters in 3297 children age 18 years or less. At highest risk were children in the top quintile of traffic density (HR = 1.21; 95% CL 0.99 to 1.49) and those who had 750 metres or more of arterial road and freeway length within 300 metres of their residence (HR = 1.18; 95% CL 0.99 to 1.41). Associations between repeated hospital encounters and residence near heavy traffic were stronger in females than males and in children without insurance or who required government sponsored insurance than children with private insurance. The gender disparity was most notable among infants (age 0) and children ages 6-18 years.

          Conclusions

          Results suggest exposure to traffic-related air pollution increases asthma severity as indicated by hospital utilisation. The finding in infants suggests this is an especially vulnerable population, although the validity of asthma diagnosis at this age is unknown. Females and children who do not have private insurance may also be more vulnerable to air pollution from traffic.
            Cover page: Repeated respiratory hospital encounters among children with asthma and residential proximity to trafficCreative Commons 'BY' version 4.0 license
            • Article
            • Peer Reviewed
            UC Irvine Previously Published Works (2009)
            Adrenergic urticaria (AU) is a rare type of physical urticaria triggered by stress. It is frequently confused with IgE-mediated urticaria or other physical urticarias. This report describes a case of localized adrenergic urticaria triggered by a sweat chloride test in an adolescent male with multiple atopic disorders. A pruritic papular rash at the site of a sweat chloride test prompted an evaluation for allergic and physical urticarias using multiple skin test methods. A positive intradermal skin test to noradrenaline, which reproduced the rash observed during the sweat test, lead to the diagnosis of adrenergic urticaria. This is the first case report describing an immediate adrenergic urticarial reaction to sweat chloride testing in a patient with other atopic disorders.
              Cover page: A case of localized adrenergic urticaria mimicking an allergic reaction to a sweat chloride testCreative Commons 'BY' version 4.0 license
              • Article
              • Peer Reviewed
              Faculty Publications (1996)

              Simultaneous measurements are reported of the nitrate radical (NO3), nitrogen dioxide (NO2), ozone (O3), and dimethylsulfide (DMS) in the nighttime marine boundary layer over Biscayne Bay in South Florida. These field observations are analyzed and used to initialize a boundary layer box model which examines the relative importance of the various sinks for NOx in the marine boundary layer. The results show that the observed lifetime of NO3 (≤6 min.) is probably controlled both by the loss of nitrogen pentoxide (N2O5) to reaction with water vapor and aerosols and by the reaction between NO3 and DMS. The model is then extended to investigate the loss of nitrogen oxides from an air parcel that remains in the boundary layer with a constant sea-to-air DMS flux for several days. The principal conclusions are (1) that DMS is a much more important sink for NO3 at lower NO2 levels and (2) that the reaction between NO3 and DMS is an important sink for DMS in the marine boundary layer and could exceed that of the daytime removal by OH.

                Cover page: Interaction between nitrogen and sulfur cycles in the polluted marine boundary layerCreative Commons 'BY' version 4.0 license
                • Article
                • Peer Reviewed
                Faculty Publications (1996)

                Shipboard measurements of atmospheric and seawater DMS were made at 12°S, 135°W for 6 days during March 1992. The mean seawater DMS concentration during this period was 4.1 ± 0.45 nM (1σ, n = 260) and the mean atmospheric DMS mole fraction was 453 ± 93 pmol mol−1 (1σ, n = 843). Consistent atmospheric diel cycles were observed, with a nighttime maximum and daytime minimum and an amplitude of approximately 85 pmol mol−1. Photochemical box model calculations were made to test the sensitivity of atmospheric DMS concentrations to the following parameters: 1) sea-to-air flux, 2) boundary layer height, 3) oxidation rate, and 4) vertical entrainment velocities. The observed relationship between the mean oceanic and atmospheric DMS levels require the use of an air-sea exchange coefficient which is at the upper limit end of the range of commonly used parameterizations. The amplitude of the diel cycle in atmospheric DMS is significantly larger than that predicted by a photochemical model. This suggests that the sea-to-air DMS flux is higher than was previously thought, and the rate of daytime oxidation of DMS is substantially underestimated by current photochemical models of DMS oxidation.

                  Cover page: Atmospheric sulfur cycling in the tropical Pacific marine boundary layer (12°S, 135°W): A comparison of field data and model results: 1. DimethylsulfideCreative Commons 'BY' version 4.0 license
                  • Article
                  • Peer Reviewed
                  ICTS Publications (2009)
                    Cover page: Skeletal muscle growth in young rats is inhibited by chronic exposure to IL-6 but preserved by concurrent voluntary endurance exerciseCreative Commons 'BY' version 4.0 license
                    • Article
                    • Peer Reviewed
                    UC Irvine Previously Published Works (2013)
                      Cover page: Pro-HEART - a randomized clinical trial to test the effectiveness of a high protein diet targeting overweight/obese individuals with heart failure: Rationale, design and baseline characteristics.
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