71 research outputs found

    Stellar spectral line synthesis from an individual photon-following simulation

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    A stochastic stellar atmosphere model which simulates the behavior of photons in the atmospheres of stars by following individual photons is described and tested. The model accounts for stellar turbulence, atmospheric curvature, stellar rotation, collisional excitation, collisional de-excitation, and stellar winds. Testing shows that this new method of stellar radiative transfer is successful in simulating all of the processes. Particular results of interest include simulation of solar limb darkening and spectral synthesis of three different solar absorption lines.http://archive.org/details/stellarspectrall1094527571Lieutenant, United States NavyApproved for public release; distribution is unlimited

    Coastal tectonics on the eastern margin of the Pacific Rim: late Quaternary sea-level history and uplift rates, Channel Islands National Park, California, USA

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    The Pacific Rim is a region where tectonic processes play a significant role in coastal landscape evolution. Coastal California, on the eastern margin of the Pacific Rim, is very active tectonically and geomorphic expressions of this include uplifted marine terraces. There have been, however, conflicting estimates of the rate of late Quaternary uplift of marine terraces in coastal California, particularly for the northern Channel Islands. In the present study, the terraces on San Miguel Island and Santa Rosa Island were mapped and new age estimates were generated using uranium-series dating of fossil corals and amino acid geochronology of fossil mollusks. Results indicate that the 2nd terrace on both islands is ~120 ka and the 1st terrace on Santa Rosa Island is ~80 ka. These ages correspond to two global high-sea stands of the Last Interglacial complex, marine isotope stages (MIS) 5.5 and 5.1, respectively. The age estimates indicate that San Miguel Island and Santa Rosa Island have been tectonically uplifted at rates of 0.12-0.20 m/ka in the late Quaternary, similar to uplift rates inferred from previous studies on neighboring Santa Cruz Island. The newly estimated uplift rates for the northern Channel Islands are, however, an order of magnitude lower than a recent study that generated uplift rates from an offshore terrace dating to the Last Glacial period. The differences between the estimated uplift rates in the present study and the offshore study are explained by the magnitude of glacial isostatic adjustment (GIA) effects that were not known at the time of the earlier study. Set in the larger context of northeastern Pacific Rim tectonics, Channel Islands uplift rates are higher than those coastal localities on the margin of the East Pacific Rise spreading center, but slightly lower than those of most localities adjacent to the Cascadia subduction zone. The uplift rates reported here for the northern Channel Islands are similar to those reported for most other localities where strike-slip tectonics are dominant, but lower than localities where restraining bends (such as the Big Bend of the San Andreas Fault) result in crustal shortening

    Pancreatic enzyme replacement therapy in patients with pancreatic cancer: A national prospective study

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    Objective: UK national guidelines recommend pancreatic enzyme replacement therapy (PERT) in pancreatic cancer. Over 80% of pancreatic cancers are unresectable and managed in non-surgical units. The aim was to assess variation in PERT prescribing, determine factors associated with its use and identify potential actions to improve prescription rates. Design: RICOCHET was a national prospective audit of malignant pancreatic, peri-ampullary lesions or malignant biliary obstruction between April and August 2018. This analysis focuses on pancreatic cancer patients and is reported to STROBE guidelines. Multivariable regression analysis was undertaken to assess factors associated with PERT prescribing. Results: Rates of PERT prescribing varied among the 1350 patients included. 74.4% of patients with potentially resectable disease were prescribed PERT compared to 45.3% with unresectable disease. PERT prescription varied across surgical hospitals but high prescribing rates did not disseminate out to the respective referring network. PERT prescription appeared to be related to the treatment aim for the patient and the amount of clinician contact a patient has. PERT prescription in potentially resectable patients was positively associated with dietitian referral (p = 0.001) and management at hepaticopancreaticobiliary (p = 0.049) or pancreatic unit (p = 0.009). Prescription in unresectable patients also had a negative association with Charlson comorbidity score 5–7 (p = 0.045) or >7 (p = 0.010) and a positive association with clinical nurse specialist review (p = 0.028). Conclusion: Despite national guidance, wide variation and under-treatment with PERT exists. Given that most patients with pancreatic cancer have unresectable disease and are treated in non-surgical hospitals, where prescribing is lowest, strategies to disseminate best practice and overcome barriers to prescribing are urgently required

    Hygiène scolaire

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    Année Académique 1976-1977info:eu-repo/semantics/published

    Contribution à l'étude structurale et fonctionnelle de la spectrine humaine

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    Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

    Fatigue du jeune enfant

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    SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Information sur quelques questions de médecine scolaire

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    2ème édition Ier tirage Année Académique 1979-1980MEDinfo:eu-repo/semantics/published

    Synthèse du diméthyl 1-2 cyclopentane

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    Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe
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