473 research outputs found

    Polar warming in the Mars thermosphere: Seasonal variations owing to changing insolation and dust distributions

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94781/1/grl20448.pd

    Martian Atmospheric Temperature and Density Profiles During the First Year of NOMAD/TGO Solar Occultation Measurements

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    We present vertical profiles of temperature and density from solar occultation (SO) observations by the “Nadir and Occultation for Mars Discovery” (NOMAD) spectrometer on board the Trace Gas Orbiter during its first operational year, which covered the second half of Mars Year 34. We used calibrated transmittance spectra in 380 scans, and apply an in-house pre-processing to clean data systematics. Temperature and CO2 profiles up to about 90 km, with consistent hydrostatic adjustment, are obtained, after adapting an Earth-tested retrieval scheme to Mars conditions. Both pre-processing and retrieval are discussed to illustrate their performance and robustness. Our results reveal the large impact of the MY34 Global Dust Storm (GDS), which warmed the atmosphere at all altitudes. The large GDS aerosols opacity limited the sounding of tropospheric layers. The retrieved temperatures agree well with global climate models (GCM) at tropospheric altitudes, but NOMAD mesospheric temperatures are wavier and globally colder by 10 K in the perihelion season, particularly during the GDS and its decay phase. We observe a warm layer around 80 km during the Southern Spring, especially in the Northern Hemisphere morning terminator, associated to large thermal tides, significantly stronger than in the GCM. Cold mesospheric pockets, close to CO2 condensation temperatures, are more frequently observed than in the GCM. NOMAD CO2 densities show oscillations upon a seasonal trend that track well the latitudinal variations expected. Results uncertainties and suggestions to improve future data re-analysis are briefly discussed

    Measurements of stratospheric constituents by ISAMS

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    ISAMS is a limb sounding radiometer flying on the UARS, and designed to measure temperature, pressure, O3, CO, NO, NO2, N2O5, HNO3, CH4, H2O, N2O, and aerosol. Its capabilities are described, together with the present status of validation of its data products, and plans for future improvement

    Nivolumab and sunitinib combination in advanced soft tissue sarcomas : A multicenter, single-arm, phase Ib/II trial

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    Sarcomas exhibit low expression of factors related to immune response, which could explain the modest activity of PD-1 inhibitors. A potential strategy to convert a cold into an inflamed microenvironment lies on a combination therapy. As tumor angiogenesis promotes immunosuppression, we designed a phase Ib/II trial to test the double inhibition of angiogenesis (sunitinib) and PD-1/PD-L1 axis (nivolumab). This single-arm, phase Ib/II trial enrolled adult patients with selected subtypes of sarcoma. Phase Ib established two dose levels: level 0 with sunitinib 37.5 mg daily from day 1, plus nivolumab 3 mg/kg intravenously on day 15, and then every 2 weeks; and level-1 with sunitinib 37.5 mg on the first 14 days (induction) and then 25 mg per day plus nivolumab on the same schedule. The primary endpoint was to determine the recommended dose for phase II (phase I) and the 6-month progression-free survival rate, according to Response Evaluation Criteria in Solid Tumors 1.1 (phase II). From May 2017 to April 2019, 68 patients were enrolled: 16 in phase Ib and 52 in phase II. The recommended dose of sunitinib for phase II was 37.5 mg as induction and then 25 mg in combination with nivolumab. After a median follow-up of 17 months (4-26), the 6-month progression-free survival rate was 48% (95% CI 41% to 55%). The most common grade 3-4 adverse events included transaminitis (17.3%) and neutropenia (11.5%). Sunitinib plus nivolumab is an active scheme with manageable toxicity in the treatment of selected patients with advanced soft tissue sarcoma, with almost half of patients free of progression at 6 months

    The challenge and scientific application of the CO2 4.3 um atmospheric limb emission of Mars

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    The atmospheric fluorescent emissions of CO2 at 4.3- um have been observed in the daytime upper atmosphere of Mars from a limb geometry by the instruments OMEGA and PFS on board Mars Express [1, 8]. Initial analysis using non-local thermodynamic equilibrium (NLTE) models show that the emissions are well understood [7, 3, 6]. Yet they have not been exploited to derive important thermospheric parameters, like CO2 densities and temperatures. Our major goals are to improve current NLTE models with a joint study of OMEGA and PFS data, and to build an ambitious state-of-the-art NLTE retreival scheme for Mars. Recent progress has been made in these directions on Mars, Venus and Earth. We will present a summary of these efforts and the difficulties and expectatives for its application to the Mars Express dat
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