Skip to main content
eScholarship
Open Access Publications from the University of California

Scholarly Works (8 results)

  • Article
LBL Publications (2004)
    Cover page: Methane Hydrate Formation and Dissociation in a Partially Saturated Sand - Measurements and Observations
    • Article
    LBL Publications (2006)

    We determined the composite thermal conductivity (ktheta) of a porous methanehydrate sample (composedof hydrate, water, and methan e gas) as a function of density using iTOUGH2. X-ray computed tomography (CT) was used to visualize and quantify the density changes that occurred during hydrate formation from granular ice. The composite thermal conductivity was estimated and validated by minimizing the differences between the observed and the predicted thermal response using history matching. The estimated density-dependent composite thermal conductivity ranged between 0.25 and 0.58 W/m/K.

      Cover page: Estimation of composite thermal conductivity of a heterogeneous methane hydrate sample using iTOUGH2
      • Article
      • Peer Reviewed
      UC San Francisco Previously Published Works (2015)

      Objective

      To determine association of socioeconomic status, defined by educational status (ES), with awareness, treatment and control of cardiovascular risk factors.

      Methods

      We performed an epidemiological study at 11 cities in India using cluster sampling. 6198 subjects (3426 men, 2772 women, response 62%, age 48±10 years) were evaluated for sociodemographic, lifestyle, anthropometric and biochemical factors. ES was categorised according to years of schooling into low (≤10 years), medium (11-15 years) and high (>15 years). Risk factors were diagnosed according to current guidelines. Awareness, treatment and control status were determined for hypertension, diabetes and hypercholesterolaemia. For smoking/tobacco use, quit rate was determined. Descriptive statistics are reported.

      Results

      Age-adjusted and sex-adjusted prevalence (%) of various risk factors in low, medium and high ES subjects was hypertension 31.8, 29.5 and 34.1, diabetes 14.5, 15.3 and 14.3, hypercholesterolaemia 24.0, 23.9 and 27.3, and smoking/tobacco use 24.3, 14.4 and 19.0. Significantly increasing trends with low, medium and high ES were observed for hypertension awareness (30.7, 37.8, 47.0), treatment (24.3, 29.2, 35.5) and control (7.8, 11.6, 15.5); diabetes awareness (47.2, 51.5, 56.4), treatment (38.3, 41.3, 46.0) and control (18.3, 15.3, 22.8); hypercholesterolaemia awareness (8.9, 22.4, 18.4), treatment (4.1, 6.2, 7.9) and control (2.8, 3.2, 6.9), as well as for smoking/tobacco quit rates (1.6, 2.8, 5.5) (χ(2) for trend, p<0.05).

      Conclusions

      Low ES subjects in India have lower awareness, treatment and control of hypertension, diabetes and hypercholesterolaemia and smoking quit rates.
        Cover page: Educational status-related disparities in awareness, treatment and control of cardiovascular risk factors in India
        • Article
        Lawrence Berkeley National Laboratory (2004)
          Cover page: Methane hydrate formation and dissociation in a partially saturated sand
          • Article
          • Peer Reviewed
          Lawrence Berkeley National Laboratory (2005)

          We performed a sequence of tests on a partially water-saturated sand sample contained in an x-ray transparent aluminum pressure vessel that is conducive to x-ray computed tomography (CT) observation. These tests were performed to gather data for estimation of thermal properties of the sand/water/gas system and the sand/hydrate/water/gas systems, as well as data to evaluate the kinetic nature of hydrate dissociation. The tests included mild thermal perturbations for the estimation of the thermal properties of the sand/water/gas system, hydrate formation, thermal perturbations with hydrate in the stability zone, hydrate dissociation through thermal stimulation, additional hydrate formation, and hydrate dissociation through depressurization with thermal stimulation. Density changes throughout the sample were observed as a result of hydrate formation and dissociation, and these processes induced capillary pressure changes that altered local water saturation.

            Cover page: Methane Hydrate Formation and Dissociation in a Partially Saturated Core-Scale Sand Sample
            • Article
            LBL Publications (2005)

            We performed a sequence of tests on a partially water-saturated sand sample contained in an x-ray transparent aluminum pressure vessel that is conducive to x-ray computed tomography (CT) observation. These tests were performed to gather data for estimation of thermal properties of the sand/water/gas system and the sand/hydrate/water/gas systems, as well as data to evaluate the kinetic nature of hydrate dissociation. The tests included mild thermal perturbations for the estimation of the thermal properties of the sand/water/gas system, hydrate formation, thermal perturbations with hydrate in the stability zone, hydrate dissociation through thermal stimulation, additional hydrate formation, and hydrate dissociation through depressurization with thermal stimulation. Density changes throughout the sample were observed as a result of hydrate formation and dissociation, and these processes induced capillary pressure changes that altered local water saturation.

              Cover page: Methane Hydrate Formation and Dissocation in a Partially Saturated Sand--Measurements and Observations
              • Article
              • Peer Reviewed
              UC San Francisco Previously Published Works (2014)

              Objective

              To determine levels of cholesterol lipoproteins and prevalence of dyslipidemias in urban Asian Indians.

              Methods

              Population based 6123 subjects (men 3388) were evaluated. Mean±1SD of various cholesterol lipoproteins (total, HDL, LDL and non-HDL cholesterol) and triglycerides were reported. Subjects were classified according to US National Cholesterol Education Program.

              Results

              Age-adjusted levels in men and women were cholesterol total 178.4 ± 39 and 184.6 ± 39, HDL 44.9 ± 11 and 51.1 ± 11, LDL 102.5 ± 33 and 106.2 ± 33, total:HDL 4.15 ± 1.2 and 3.79 ± 1.0 and triglycerides 162.5 ± 83 and 143.7 ± 83 mg/dl. Age-adjusted prevalence (%) in men and women, respectively were, total cholesterol ≥200 mg/dl 25.1 and 24.9, LDL cholesterol ≥130 mg/dl 16.3 and 15.1 and ≥100 mg/dl 49.5 and 49.7, HDL cholesterol <40/<50 mg/dl 33.6 and 52.8, total:HDL cholesterol ≥4.5 29.4 and 16.8, and triglycerides ≥150 mg/dl 42.1 and 32.9%. Cholesterol level was significantly greater in subjects with better socioeconomic status, body mass index and waist circumference while triglycerides were more among those with high socioeconomic status, fat intake, body mass index and waist circumference (p < 0.05). Hypercholesterolemia awareness (15.6%), treatment (7.2%) and control (4.1%) were low.

              Conclusions

              Mean cholesterol and LDL cholesterol are low and triglycerides were high in urban Asian Indians. Most prevalent dyslipidemias are borderline high LDL, low HDL and high triglycerides. Subjects with high socioeconomic status, high fat intake and greater adiposity have higher total and LDL cholesterol and triglyceride and lower HDL cholesterol.
                Cover page: Cholesterol lipoproteins and prevalence of dyslipidemias in urban Asian Indians: A cross sectional study
                • Article
                • Peer Reviewed
                UC Berkeley Previously Published Works (2020)
                We report the detection of a Saturn-size exoplanet orbiting HD 332231 (TOI 1456) in light curves from the Transiting Exoplanet Survey Satellite (TESS). HD 332231 - an F8 dwarf star with a V-band magnitude of 8.56 - was observed by TESS in Sectors 14 and 15. We detect a single-transit event in the Sector 15 presearch data conditioning (PDC) light curve. We obtain spectroscopic follow-up observations of HD 332231 with the Automated Planet Finder, Keck I, and SONG telescopes. The orbital period we infer from radial velocity (RV) observations leads to the discovery of another transit in Sector 14 that was masked by PDC due to scattered light contamination. A joint analysis of the transit and RV data confirms the planetary nature of HD 332231 b, a Saturn-size (0.867-0.025+0.027RJ), sub-Saturn-mass (0.244±0.021MJ) exoplanet on a 18.71 day circular orbit. The low surface gravity of HD 332231 b and the relatively low stellar flux it receives make it a compelling target for transmission spectroscopy. Also, the stellar obliquity is likely measurable via the Rossiter-McLaughlin effect, an exciting prospect given the 0.14 au orbital separation of HD 332231 b. The spectroscopic observations do not provide substantial evidence for any additional planets in the HD 332231 system, but continued RV monitoring is needed to further characterize this system. We also predict that the frequency and duration of masked data in the PDC light curves for TESS Sectors 14-16 could hide transits of some exoplanets with orbital periods between 10.5 and 17.5 days.
                  Cover page: The TESS–Keck Survey. I. A Warm Sub-Saturn-mass Planet and a Caution about Stray Light in TESS Cameras* * Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation.Creative Commons 'BY' version 4.0 license
                  Top