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- SourceAvailable from: E. Moulin[Show abstract] [Hide abstract]
ABSTRACT: We report on the first completely simultaneous observation of a gamma-ray burst (GRB) using an array of Imaging Atmospheric Cherenkov Telescopes, which is sensitive to photons in the very high energy (VHE) γ -ray range (100 GeV). On 2006 June 2, the Swift Burst Alert Telescope (BAT) registered an unusually soft γ -ray burst (GRB 060602B). The burst position was under observation using the High Energy Stereoscopic System (HESS) at the time the burst occurred. Data were taken before, during, and after the burst. A total of 5 hr of observations were obtained during the night of 2006 June 2–3, and five additional hours were obtained over the next three nights. No VHE γ -ray signal was found during the period covered by the HESS observations. The 99% confidence level flux upper limit (> 1 TeV) for the prompt phase (9 s) of GRB 060602B is 2.9 × 10 −9 erg cm −2 s −1 . Due to the very soft BAT spectrum of the burst compared with other Swift GRBs and its proximity to the Galactic center, the burst is likely associated with a Galactic X-ray burster, although the possibility of it being a cosmological GRB cannot be ruled out. We discuss the implications of our flux limits in the context of these two bursting scenarios.
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ABSTRACT: Shift work is indicated to be associated with adverse metabolic disorders. However, potential effects of shift work on metabolic syndrome (MetS) and its components have not been well established. In total, 26,382 workers from Dongfeng-Tongji Cohort were included in this study. Information on shift work history was gathered through questionnaires and metabolic traits were measured. Logistic regression models were used to calculate the odds ratio (OR) and 95% confidence interval (CI) for long-term shift work related with MetS and each component, respectively. Further stratification analysis was performed to detect the differences on MetS between female and male shift workers. Long-term shift work was associated with MetS without adjusting for any confounders. Compared with the group of non-shift work, the multivariate-adjusted ORs (95%CI) of MetS associated with 1-10, 11-20, and ≥20y of shift work were 1.05 (0.95-1.16), 1.14 (1.03-1.26), 1.16 (1.01-1.31), respectively. In female workers, we found a dose-response relationship that every 10 years increase in shift work was associated with a 10% (95% CI: 1%-20%) elevated OR of MetS, while no significant dose-response trend was found among male workers. Furthermore, shift work duration was significantly associated with ORs of high blood pressure (1.07, 1.01-1.13), long waist circumference (1.10, 1.01-1.20) and high glucose levels (1.09, 1.04-1.15). No significant association was observed between shift work and low HDL cholesterol) and raised triglyceride levels. Long-term shift work was associated with metabolic syndrome and the association might differ by gender in retired workers. Applicable intervention strategies are needed for prevention of metabolic disorders for shift workers.PLoS ONE 03/2015; 10(3):e0120632. DOI:10.1371/journal.pone.0120632
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ABSTRACT: This study was conducted to estimate the cause-specific mortality in male emergency responders (ER), compare with that of Korean men. Mortality was also compared between more experienced firefighters (i.e., firefighters employed ≥20 years and firefighters employed ≥10 to <20 years) and less experienced firefighters and non-firefighters (i.e., firefighters employed <10 years and non-firefighters) to investigate associations between mortality and exposure to occupational hazards. The cohort was comprised of 33,442 males who were employed as ERs between 1980 and 2007 and not deceased as of 1991. Work history was merged with the death registry from the National Statistical Office of Korea to follow-up on mortality between 1992 and 2007. Standardized mortality ratios (SMR) for ERs were calculated in reference to the Korean male population. Adjusted relative risks (ARRs) of mortalities for firefighters employed ≥20 years and ≥10 years to <20 years were calculated in reference to non-firefighters and firefighters employed < 10 years. Overall (SMR=0.43, 95%CI=0.39-0.47) and some kinds of cause-specific mortalities were significantly lower among ERs compared with the Korean male population. No significant increase in mortality was observed across the major ICD-10 classifications among ERs. Mortality due to exposure to smoke, fire, and flames (SMR=3.11, 95% CI=1.87-4.85), however, was significantly increased among ERs. All-cause mortality (ARR=1.46, 95% CI=1.13-1.89), overall cancer mortality (ARR=1.54, 95% CI=1.02-2.31) and mortality of external injury, poisoning and external causes (ARR=3.13, 95% CI=1.80-5.46) were significantly increased among firefighters employed ≥20 years compared to those of non-firefighters and firefighters employed < 10 years. An increase in mortality due to all cancer and external injury, poisoning, and external causes in firefighters employed ≥20 years compared with non-firefighters and firefighters employed <10 years suggests occupational exposure.PLoS ONE 03/2015; 10(3):e0120305. DOI:10.1371/journal.pone.0120305