Altimetry for the future: Building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Altimetry for the future: building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Revue d'histoire du Bas Saint-Laurent, vol. 4 (1)

Éditorial: Outils indispensables à l'histoire régionale -- Les chantiers d'autrefois -- Les obligations d'un "gars" de chantier -- Il y a quarante ans...quand les "barons" du bois tenaient un pays sous leur loi -- Un projet audacieux. Hubert Gagnon au fond d'ormes -- Une chronique: 1907 à Lac-au-Saumon -- Histoire d'une peur. La vision du communisme dans le "Progrès du Golfe" -- Débats politiques et moeurs électorales dans le comté de Rimouski en 1891 -- Jean Bernard Pelletier écuier notaire assure ses vieux jour

CD36 Displays Features of a Lipid-Sensor Involved in Chylomicron Processing in the Rodent Small Intestine

International audienceThe membrane glycoprotein CD36 binds nanomolar concentrations of long-chain fatty acids (LCFA) and is highly expressed on the luminal surface of enterocytes. CD36 deficiency reduces chylomicron production through unknown mechanisms.In this report, we provide novel insights into the potential underlying mechanisms. Our in vivo data demonstrated that CD36 gene deletion in mice did not affect LCFA uptake and their subsequent esterification into triglycerides by the intestinal mucosa at micellar LCFA concentrations prevailing in the intestine. In rodents, CD36 protein early disappeared from the luminal side of intestinal villi during the post-prandial period but only when the diet contained lipids. This drop was significant 1 h after a lipid supply and was associated with an ubiquitination of CD36 as reported during the ligand receptor desensitization process. Using CHO cells expressing CD36, it is shown that the digestion products, LCFA and diglycerides, triggered the CD36 ubiquitination. In vivo treatment with the proteasome inhibitor MG132 prevented the lipid-mediated degradation of CD36 and the up-regulation of L-FABP, a key gene implicated in the formation and secretion of large chylomicrons. Since the L-FABP up-regulation by lipids remained abolished in CD36-null mice with and without MG132, CD36 degradation appears to be linked to the chylomicron formation.Therefore, intestinal CD36 displays features of a lipid sensor involving in the adaptation of enterocyte metabolism to the post-prandial lipid challenge by producing large triglyceride-rich lipoproteins rapidly cleared in blood. This finding raises the possibility of alternative therapeutic approaches to reduce the post-prandial hypertriglyceridemia and prevent cardiovascular risks