.

International audienc

Mapping in pig of genes involved in sexual differentiation : AMH, WT1, FTZF1, SOX2, SOX9, ACH, and placental and embryonic CYP19

Chantier qualité spécifique "Auteurs Externes" département de Génétique animale : uniquement liaison auteur au référentiel HR-AccessInternational audienc

Experimental investigations of SPT operation on alternative to xenon gases - N2, Kr

[Poster - Id :430]International audienc

Intercomparison of peroxy radical instruments at the HELIOS atmospheric simulation chamber

International audiencePeroxy radicals (HO 2 and RO 2 ) are key species in atmospheric chemistry, which together with the hydroxyl radical (OH), are involved in oxidation processes leading to the formation of secondary pollutants such as ozone and organic aerosols. Monitoring these short-lived species during intensive field campaigns and comparing the measured concentrations to box model simulations allow assessing the reliability of chemical mechanisms implemented in atmospheric models. However, ambient measurements of peroxy radicals are still considered challenging and only a few techniques have been used for field measurements. Three complementary instruments capable of ambient measurements of pe roxy radicals have been deployed together at the HELIOS atmospheric simulation chamber (Orléans, France) in October 2018. These instruments rely on the PEroxy Radical Chemical Amplification (PERCA), Laser Induced Fluorescence-Fluorescent Assay by Gas Expansion (LIF-FAGE), and Chemical Ionisation Mass Spectrometry (CIMS) techniques. Several chamber experiments have been conducted under dark and irradiated conditions, including oxidation experiments of dihydrogen, methane, pentene, isoprene, and α-pinene. In this presentation, the agreement between the different instruments will be discussed in the light of supporting measurements of volatile organic compounds and inorganic species (O3, NO, NO2), photolysis frequencies, as well as box modelling of the chamber chemistry

Intercomparison of peroxy radical instruments at the HELIOS atmospheric simulation chamber

International audiencePeroxy radicals (HO 2 and RO 2 ) are key species in atmospheric chemistry, which together with the hydroxyl radical (OH), are involved in oxidation processes leading to the formation of secondary pollutants such as ozone and organic aerosols. Monitoring these short-lived species during intensive field campaigns and comparing the measured concentrations to box model simulations allow assessing the reliability of chemical mechanisms implemented in atmospheric models. However, ambient measurements of peroxy radicals are still considered challenging and only a few techniques have been used for field measurements. Three complementary instruments capable of ambient measurements of pe roxy radicals have been deployed together at the HELIOS atmospheric simulation chamber (Orléans, France) in October 2018. These instruments rely on the PEroxy Radical Chemical Amplification (PERCA), Laser Induced Fluorescence-Fluorescent Assay by Gas Expansion (LIF-FAGE), and Chemical Ionisation Mass Spectrometry (CIMS) techniques. Several chamber experiments have been conducted under dark and irradiated conditions, including oxidation experiments of dihydrogen, methane, pentene, isoprene, and α-pinene. In this presentation, the agreement between the different instruments will be discussed in the light of supporting measurements of volatile organic compounds and inorganic species (O3, NO, NO2), photolysis frequencies, as well as box modelling of the chamber chemistry

Observations of trace gases above & below a forest canopy during ACROSS

International audienceThe ACROSS campaign (Atmospheric chemistry of the suburban forest) is a collaborative effort to better understand how the mixing between urban and biogenic air masses impacts atmospheric composition and reactivity. A main objective is to provide a detailed description of physico-chemical processes involved in atmospheric transformations of biogenic Volatile Organic Compounds (VOCs), and the myriad of intermediate species formed as a consequence, which have yet to be characterized. This multi-platform campaign took place during summer 2022 for a duration of 6 weeks and included a supersite in the Rambouillet forest located on the path of pollution plumes from Paris. An unprecedented suite of analytical instruments was deployed at this site to probe air masses at the ground level and above the forest canopy using a 40-m tower.This presentation will focus on trace gas observations, including VOCs, ROx (OH+HO2+RO2) and selected inorganic species (O3, NOx – NO+NO2), both above and below the forest canopy. A descriptive analysis will be presented to highlight biogenic VOC oxidation regimes taking place under unpolluted (oceanic air masses) and polluted (Paris plumes) conditions, with a focus on primary/secondary species. Chemical compositions observed above and below-canopy will also be contrasted. On the basis of these observations, this presentation will highlight scientific questions related to ROx, VOC and NOx budgets that will be further investigated to fill important gaps in our understanding of biogenic VOC transformations and secondary organic aerosol formation

Observations of trace gases above & below a forest canopy during ACROSS

International audienceThe ACROSS campaign (Atmospheric chemistry of the suburban forest) is a collaborative effort to better understand how the mixing between urban and biogenic air masses impacts atmospheric composition and reactivity. A main objective is to provide a detailed description of physico-chemical processes involved in atmospheric transformations of biogenic Volatile Organic Compounds (VOCs), and the myriad of intermediate species formed as a consequence, which have yet to be characterized. This multi-platform campaign took place during summer 2022 for a duration of 6 weeks and included a supersite in the Rambouillet forest located on the path of pollution plumes from Paris. An unprecedented suite of analytical instruments was deployed at this site to probe air masses at the ground level and above the forest canopy using a 40-m tower.This presentation will focus on trace gas observations, including VOCs, ROx (OH+HO2+RO2) and selected inorganic species (O3, NOx – NO+NO2), both above and below the forest canopy. A descriptive analysis will be presented to highlight biogenic VOC oxidation regimes taking place under unpolluted (oceanic air masses) and polluted (Paris plumes) conditions, with a focus on primary/secondary species. Chemical compositions observed above and below-canopy will also be contrasted. On the basis of these observations, this presentation will highlight scientific questions related to ROx, VOC and NOx budgets that will be further investigated to fill important gaps in our understanding of biogenic VOC transformations and secondary organic aerosol formation