22 research outputs found

    Sur les relations croisées des caractÚres antigÚnes et immunigÚnes des virus de la maladie de Carré et de la peste bovine : état actuel des recherches

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    1) Le virus de la peste bovine est susceptible d'infecter les carnivores et provoque chez eux une maladie cliniquement inapparente, mais génératrice d'anticorps neutralisants. Le virus de la maladie de Carré (souche furet) provoque chez les bovins une infection inapparente, décelable seulement par les techniques sérologiques. Les souches avianisées possÚdent un pouvoir infectant irrégulier. 2) L'infection par le virus de la peste bovine confÚre aux carnivores une résistance solide à la maladie de Carré, immunité vraie, solide et durable (au moins 11 mois et demi). Réciproquement, l'infection par le virus de Carré confÚre aux bovins une immunité solide contre la peste bovine. 3) Les sérums contre la peste bovine neutralisent le virus de Carré in ovo et in vivo à des dilutions analogues à celles des sérums homologues. Les sérums contre la maladie de Carré neutralisent faiblement et irréguliÚrement contre le virus bovipestique. 4) Le lapin semble indifférent au virus de Carré, qui n'engendre chez lui ni l'immunité ni la formation d'anticorps neutralisants. 5) La structure antigénique du virus bovipestique semble plus complexe que celle du virus de Carré, qui représenterait une forme dégradée de celui-ci

    Euclid: modelling massive neutrinos in cosmology - a code comparison

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    Material outgassing in a vacuum leads to molecular contamination, a well-known problem in spaceflight. Water is the most common contaminant in cryogenic spacecraft, altering numerous properties of optical systems. Too much ice means that Euclid’s calibration requirements cannot be met anymore. Euclid must then be thermally decontaminated, which is a month-long risky operation. We need to understand how ice affects our data to build adequate calibration and survey plans. A comprehensive analysis in the context of an astrophysical space survey has not been done before. In this paper we look at other spacecraft with well-documented outgassing records. We then review the formation of thin ice films, and find that for Euclid a mix of amorphous and crystalline ices is expected. Their surface topography – and thus optical properties – depend on the competing energetic needs of the substrate-water and the water-water interfaces, and they are hard to predict with current theories. We illustrate that with scanning-tunnelling and atomic-force microscope images of thin ice films. Sophisticated tools exist to compute contamination rates, and we must understand their underlying physical principles and uncertainties. We find considerable knowledge errors on the diffusion and sublimation coefficients, limiting the accuracy of outgassing estimates. We developed a water transport model to compute contamination rates in Euclid, and find agreement with industry estimates within the uncertainties. Tests of the Euclid flight hardware in space simulators did not pick up significant contamination signals, but they were also not geared towards this purpose; our in-flight calibration observations will be much more sensitive. To derive a calibration and decontamination strategy, we need to understand the link between the amount of ice in the optics and its effect on the data. There is little research about this, possibly because other spacecraft can decontaminate more easily, quenching the need for a deeper understanding. In our second paper, we quantify the impact of iced optics on Euclid’s data

    Euclid preparation. XXIX. Water ice in spacecraft part I:The physics of ice formation and contamination

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    Molecular contamination is a well-known problem in space flight. Water is the most common contaminant and alters numerous properties of a cryogenic optical system. Too much ice means that Euclid's calibration requirements and science goals cannot be met. Euclid must then be thermally decontaminated, a long and risky process. We need to understand how iced optics affect the data and when a decontamination is required. This is essential to build adequate calibration and survey plans, yet a comprehensive analysis in the context of an astrophysical space survey has not been done before. In this paper we look at other spacecraft with well-documented outgassing records, and we review the formation of thin ice films. A mix of amorphous and crystalline ices is expected for Euclid. Their surface topography depends on the competing energetic needs of the substrate-water and the water-water interfaces, and is hard to predict with current theories. We illustrate that with scanning-tunnelling and atomic-force microscope images. Industrial tools exist to estimate contamination, and we must understand their uncertainties. We find considerable knowledge errors on the diffusion and sublimation coefficients, limiting the accuracy of these tools. We developed a water transport model to compute contamination rates in Euclid, and find general agreement with industry estimates. Tests of the Euclid flight hardware in space simulators did not pick up contamination signals; our in-flight calibrations observations will be much more sensitive. We must understand the link between the amount of ice on the optics and its effect on Euclid's data. Little research is available about this link, possibly because other spacecraft can decontaminate easily, quenching the need for a deeper understanding. In our second paper we quantify the various effects of iced optics on spectrophotometric data

    Euclid preparation. XXIX. Water ice in spacecraft part I: The physics of ice formation and contamination

    Get PDF
    Molecular contamination is a well-known problem in space flight. Water is the most common contaminant and alters numerous properties of a cryogenic optical system. Too much ice means that Euclid's calibration requirements and science goals cannot be met. Euclid must then be thermally decontaminated, a long and risky process. We need to understand how iced optics affect the data and when a decontamination is required. This is essential to build adequate calibration and survey plans, yet a comprehensive analysis in the context of an astrophysical space survey has not been done before. In this paper we look at other spacecraft with well-documented outgassing records, and we review the formation of thin ice films. A mix of amorphous and crystalline ices is expected for Euclid. Their surface topography depends on the competing energetic needs of the substrate-water and the water-water interfaces, and is hard to predict with current theories. We illustrate that with scanning-tunnelling and atomic-force microscope images. Industrial tools exist to estimate contamination, and we must understand their uncertainties. We find considerable knowledge errors on the diffusion and sublimation coefficients, limiting the accuracy of these tools. We developed a water transport model to compute contamination rates in Euclid, and find general agreement with industry estimates. Tests of the Euclid flight hardware in space simulators did not pick up contamination signals; our in-flight calibrations observations will be much more sensitive. We must understand the link between the amount of ice on the optics and its effect on Euclid's data. Little research is available about this link, possibly because other spacecraft can decontaminate easily, quenching the need for a deeper understanding. In our second paper we quantify the various effects of iced optics on spectrophotometric data.Comment: 35 pages, 22 figures, A&A in press. Changes to previous version: language edits, added Z. Bolag as author in the arxiv PDF (was listed in the ASCII author list and in the journal PDF, but not in the arxiv PDF). This version is identical to the journal versio

    Comportement humoral du bƓuf et du lapin envers l’inoculation de virus de CarrĂ© : ses rapports avec l’immunisation contre le virus bovipestique normal ou modifiĂ©

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    Gilbert Y., Mornet Paul, Goueffon Y., Goret Pierre. Comportement humoral du bƓuf et du lapin envers l’inoculation de virus de CarrĂ© : ses rapports avec l’immunisation contre le virus bovipestique normal ou modifiĂ©. In: Bulletin de l'AcadĂ©mie VĂ©tĂ©rinaire de France tome 113 n°5, 1960. pp. 305-316
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