19 research outputs found

    Altimetry for the future: Building on 25 years of progress

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    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

    Get PDF
    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

    Chronic neutral phosphate supplementation induces sustained, renal metabolic alkalosis

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    Chronic neutral phosphate supplementation induces sustained, renal metabolic alkalosis. The aim of the present study was to test whether intravenous neutral phosphate supplementation, recently shown in our laboratory to acutely stimulate proton secretion in the distal nephron, was able to induce a sustained metabolic alkalosis. Neutral Na and K phosphate supplementation for seven days, with equivalent reduction in chloride supply and unchanged intake of sodium and potassium, in ADX rats receiving fixed physiological doses of aldosterone and dexa-methasone (group 1, N = 7), was responsible for a severe metabolic alkalosis (MA; Δ [HCO3] 11 ± 1.3mM, and Δ pH 0.11 ± 0.06 unit). Metabolic alkalosis was at least in part of renal origin, since net acid excretion (NAE) transiently increased, principally due to an increment in titratable acid excretion rate. Balances were equilibrated for sodium and negative for chloride and potassium, which may have contributed to the severity of the MA. Chronic i.v. neutral Na phosphate, without change in potassium and chloride supply, in ADX rats receiving the same doses of steroids (group 2, N = 5), was responsible for a less severe MA (Δ [HCO3] 7.5 ± 0.9mM, and Δ pH 0.07 ± 0.01 unit), also of renal origin. In this group, balances were positive for chloride and sodium and equilibrated for potassium. Finally, neutral Na and K phosphate supplementation with reduction in chloride supply in intact rats (group 3, N = 4) was also able to induce a MA (Δ [HCO3] 5.5 ± 1.8mM, and Δ pH 0.06 ± 0.01 unit) of renal origin, with balances negative for chloride and equilibrated for potassium and sodium. In all groups, the generation and maintenance of MA probably resulted from stimulated proton secretion in the distal nephron, as suggested by the observed increase of PCO2 over HCO3 concentration ratio in the urine and a fall in urine pH despite augmented urinary buffer content throughout the phosphate infusion period. Glomerular filtration rate did not significantly vary in any group. In conclusion, chronic supplementation of neutral phosphate appears to stimulate per se proton secretion in the distal nephron, independently of sodium, chloride, and potassium balances, and adrenal steroid secretion. Thus neutral phosphate supplementation should be added to the previously known factors able to induce MA

    ALISA, une alimentation saine et durable, conception d'un programme de prévention pour les personnes de plus de 55 ans

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    National audienceIntroduction et but de l’étudeDans le contexte d'une population vieillissante, oĂč prĂšs de 20% des individus ont dĂ©passĂ© l'Ăąge de 65 ans (1), la prĂ©servation du capital santĂ©, la qualitĂ© de l’alimentation et le maintien de l'autonomie deviennent des enjeux essentiels. Ces Ă©lĂ©ments rejoignent des dĂ©fis sociĂ©taux tels que la transition alimentaire, la durabilitĂ©, l'accessibilitĂ© alimentaire, le bien-ĂȘtre et le plaisir alimentaire. Pour relever ceux-ci, un programme de prĂ©vention dĂ©diĂ© Ă  l'alimentation des seniors a Ă©tĂ© conçu en se basant sur leurs besoins et attentes. Le but de cette Ă©tude est de concevoir un programme adaptĂ©, Ă  destination des plus de 55 ans.MatĂ©riel et mĂ©thodes45 sujets de plus de 55 ans ont Ă©tĂ© recrutĂ©s dans un pĂŽle senior, un centre social et une rĂ©sidence autonomie afin de former six groupes (7 participants par groupe) de discussion. La majoritĂ©, soit 24 d'entre eux, avaient plus de 76 ans, 42 Ă©taient des femmes, 3 Ă©taient des hommes, 42 Ă©taient des retraitĂ©s. Le guide d'animation comprend six catĂ©gories de thĂ©matiques en relation avec l'alimentation, les connaissances sur l'alimentation saine, la sensibilitĂ© Ă  la notion de durabilitĂ©, les pratiques alimentaires (approvisionnement en cuisine, environnement du repas), et le lien intergĂ©nĂ©rationnel. L’analyse a Ă©tĂ© rĂ©alisĂ©e Ă  partir d’observations lors des ateliers et d'entretiens posts-ateliers.RĂ©sultats et analyses statistiquesL’analyse a montrĂ© que les principaux verbatims associĂ©s au rĂŽle de l'alimentation Ă©taient le plaisir, la convivialitĂ©, la contrainte, la nĂ©cessitĂ©, et le traditionnel. Concernant la conception de l'alimentation saine, les catĂ©gories identifiĂ©es sont : les produits (fruits, lĂ©gumes, produits non traitĂ©s, non prĂ©parĂ©s), l'Ă©quilibre, la diversitĂ©, les caractĂ©ristiques des aliments (de saison, biologiques), la santĂ© (respect des avis mĂ©dicaux, gestion du poids), et les contraintes (budget, accessibilitĂ© et variĂ©tĂ©, motivation Ă  cuisiner pour soi). Concernant les pratiques alimentaires, les principaux lieux frĂ©quentĂ©s pour les courses sont les supermarchĂ©s, suivis des marchĂ©s, des producteurs locaux et des petits commerces. Les critĂšres de choix comprennent la diversitĂ©, l'aspect, la fraĂźcheur et les indicateurs de qualitĂ©. Les difficultĂ©s rencontrĂ©es sont le manque de diversitĂ©, la routine alimentaire, les Ă©tiquettes trop complexes et le marketing trompeur. De plus, certains participants cuisinent rĂ©guliĂšrement tandis que d'autres optent pour des plats prĂ©parĂ©s. Globalement, cette population frĂ©quente rarement les restaurants. Certains voient la cuisine comme une corvĂ©e, d'autres comme un plaisir, surtout en prĂ©sence d'invitĂ©s. Certains sont curieux d'apprendre de nouvelles techniques et recettes simples, ainsi que d'explorer les cuisines du monde. En ce qui concerne l'environnement du repas, ceux en compagnie sont prĂ©fĂ©rĂ©s aux repas solitaires. Le lien intergĂ©nĂ©rationnel a Ă©galement Ă©tĂ© abordĂ©, mettant en Ă©vidence deux attitudes dominantes : le dĂ©sir de procurer du plaisir aux petits-enfants et l'intention d'apporter une Ă©ducation alimentaire Ă  ces derniers. Ainsi, un programme appelĂ© ALISA, « ALImentation Saine durable et Accessible », en 4 ateliers participatifs a Ă©tĂ© construit et proposĂ© Ă  des villes partenaires. Le premier atelier est axĂ© sur le souvenir et la notion de plaisir pour embarquer les participants grĂące Ă  une dĂ©gustation d’un aliment en pleine conscience. Ensuite, un jeu de cartes «Question pour un oignon» vient apporter des notions essentielles en termes d’alimentation pour les seniors, suivi d’un atelier apportant des conseils pratiques pour mieux apprĂ©hender les repas, via la lecture d’étiquettes, les mĂ©thodes d’approvisionnements ou encore la notion de durabilitĂ©. Enfin, un atelier pratique culinaire avec un livret de recettes adaptĂ©es, simples, et Ă  petit budget est proposĂ©.ConclusionLes rĂ©sultats de ces groupes de discussion ont orientĂ© les contenus des actions de proximitĂ© destinĂ©es Ă  ce public. Plusieurs thĂ©matiques sont ressorties permettant de construire 4 ateliers portant sur le souvenir, les besoins nutritionnels, la durabilitĂ© et l’accessibilitĂ© ainsi que les dĂ©couvertes et pratiques culinaires. Des divergences ont Ă©tĂ© observĂ©es au sein des groupes concernant la perception de l'alimentation comme une corvĂ©e quotidienne pour certains, et comme un plaisir et une source de curiositĂ© pour d'autres. Par consĂ©quent il est essentiel de, placer le plaisir et le divertissement au coeur des actions de proximitĂ© visant l’alimentation des personnes de plus de 55 ans
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