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15. Statistical post-processing of ensemble forecasts of the height of new snow

Author

Nousu, J.-P. (Jari-Pekka), Lafaysse, M. (Matthieu), Vernay, M. (Matthieu), Bellier, J. (Joseph), Evin, G. (Guillaume), Joly, B. (Bruno), Nousu, J.-P. (Jari-Pekka), Lafaysse, M. (Matthieu), Vernay, M. (Matthieu), Bellier, J. (Joseph), Evin, G. (Guillaume), and Joly, B. (Bruno)

Abstract

Forecasting the height of new snow (HN) is crucial for avalanche hazard forecasting, road viability, ski resort management and tourism attractiveness. Météo-France operates the PEARP-S2M probabilistic forecasting system, including 35 members of the PEARP Numerical Weather Prediction system, where the SAFRAN downscaling tool refines the elevation resolution and the Crocus snowpack model represents the main physical processes in the snowpack. It provides better HN forecasts than direct NWP diagnostics but exhibits significant biases and underdispersion. We applied a statistical post-processing to these ensemble forecasts, based on non-homogeneous regression with a censored shifted Gamma distribution. Observations come from manual measurements of 24 h HN in the French Alps and Pyrenees. The calibration is tested at the station scale and the massif scale (i.e. aggregating different stations over areas of 1000 km²). Compared to the raw forecasts, similar improvements are obtained for both spatial scales. Therefore, the post-processing can be applied at any point of the massifs. Two training datasets are tested: (1) a 22-year homogeneous reforecast for which the NWP model resolution and physical options are identical to the operational system but without the same initial perturbations; (2) 3-year real-time forecasts with a heterogeneous model configuration but the same perturbation methods. The impact of the training dataset depends on lead time and on the evaluation criteria. The long-term reforecast improves the reliability of severe snowfall but leads to overdispersion due to the discrepancy in real-time perturbations. Thus, the development of reliable automatic forecasting products of HN needs long reforecasts as homogeneous as possible with the operational systems.

Published
2019

17. P19-1 - Comment est mesuré l’état de santé perçue de populations riveraines d'installations industrielles ? Une « scoping review »

Author

Trouillet, M., Dab, W., and Vernay, M.

Abstract

Dans de nombreux pays, on observe une sensibilité croissante de la population pour la qualité des environnements de vie, en particulier, autour d'installations industrielles. Pour y répondre, les agences de sécurité sanitaire de plusieurs pays ont mené des études épidémiologiques, centrées sur des critères de mortalité ou de morbidité caractérisés médicalement. Pour apporter une réponse complète, ces agences ont élargi le champ à la mesure de la santé perçue. Néanmoins, ces approches ont été menées au cas par cas sans qu'il existe une conduite à tenir. Il est donc apparu nécessaire de réaliser un travail d'identification de ces outils grâce à une « scoping review ». Ce travail a pour objectif d'analyser comment la validité et la fiabilité des outils ont été appréhendées dans les articles.

Published
2024
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18. Effect of protein-protected fat on ruminal and total nutrient digestibility of sheep diets

Author

Bayourthe, C., Moncoulon, R., and Vernay, M.

Subjects
Sheep -- Food and nutrition, Dietary supplements -- Research, Rumination -- Research, Zoology and wildlife conservation
Abstract

Experiments were conducted to determine the effects of supplementing chopped ryegrass hay with 0, 5, 10, or 20% fat coated with ruminal bypass protein (Prolip|R~ on ruminal digestion by cows and nutrient digestibility by sheep. Ruminal disappearances of DM, ADF, and NDF were measured by the in sacco technique using a cannulated cow. Degradation of DM, ADF, and NDF was not affected by protected fat supplementation at the 5, 10, or 20% level during the first 16 h in the rumen. In addition, supplementation with Prolip did not influence in vitro fermentation characteristics such as pH and VFA patterns. A digestibility experiment with six mature sheep in a switch-back design showed no decrease in feed intake or other undesired effects between unsupplemented (basal) and Prolip-supplemented diets. Whatever the diet fed to sheep, fiber digestibility was similar; however, DM and nitrogen digestibilities were significantly higher relative to the basal diet when ryegrass hay was substituted at 20% (64.2 vs 59.0% and 74.1 vs 71.1%, respectively). Ether extract digestion was enhanced by increasing level of Prolip; the corresponding values were 48.0, 64.9, 74.6, and 84.6% at 0, 5, 10, or 20% Prolip. Likewise, Prolip supplementation at the 10 or 20% level augmented digestibility of energy (62.7 or 65.9 vs 59.2%). Nitrogen and energy retentions were improved due to the decreases in fecal and(or) urinary excretion(s).

Published
1993

21. Acute phase response in lactating dairy cows during hyperinsulinemic hypoglycaemic and hyperinsulinemic euglycaemic clamps and after intramammary LPS challenge.

Author

De Matteis, L., Bertoni, G., Lombardelli, R., Wellnitz, O., Van Dorland, H. A., Vernay, M. C. M. B., Bruckmaier, R. M., and Trevisi, E.

Subjects
HYPERINSULINISM, LACTATION in cattle, LIPOPOLYSACCHARIDES, TUMOR necrosis factors, HAPTOGLOBINS
Abstract

The link between energy availability, turnover of energy substrates and the onset of inflammation in dairy cows is complex and poorly investigated. To clarify this, plasma inflammatory variables were measured in mid-lactating dairy cows allocated to three groups: hyperinsulinemic hypoglycaemic clamp, induced by insulin infusion (HypoG, n = 5); hyperinsulinemic euglycaemic clamp, induced by insulin and glucose infusion (EuG; n = 6); control, receiving a saline solution infusion (NaCl; n = 6). At 48 h after the start of i.v. infusions, two udder quarters per cow were challenged with 200 μg of E. coli lipopolysaccharide ( LPS). Individual blood samples were taken before clamps, before LPS challenge (i.e. 48 h after clamps) and 6.5 h after. At 48 h, positive acute phase proteins (pos APP) did not differ among groups, whereas albumin and cholesterol (index of lipoproteins), negative APP (neg APP), were lower (p < 0.05) in EuG compared to NaCl and HypoG. The concentration of IL-6 was greater in EuG (p < 0.05) but only vs. HypoG. At 6.5 h following LPS challenge, IL-6 increased in the NaCl and EuG clamps (p < 0.05), while TNF- α increased (p < 0.05) in the EuG only. Among the pos APP, haptoglobin markedly increased in EuG (p < 0.05), but not in NaCl (p = 0.76) and in HypoG; ceruloplasmin tended to decline during LPS challenge, the reduction was significant when all animals were considered (p < 0.05). Conversely, all the neg APP showed a marked reduction 6.5 h after LPS challenge in the three groups. In conclusion, EuG caused an inflammatory status after 48-h infusion (i.e. decrease of neg APP) and induced a quicker acute phase response (e.g. marked rise of TNF- α, IL-6) after the intramammary LPS challenge. These data suggest that the simultaneous high availability of glucose and insulin at the tissue-level makes dairy cows more susceptible to inflammatory events. In contrast, HypoG seems to attenuate the inflammatory response. [ABSTRACT FROM AUTHOR]

Published
2017
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44. Sulla tenzone di anonimi L331-332

Author

P. Gresti, S. Perrin, Ph. Vernay, M. Zenari, M.C. Gerard-Zai, Gresti, Paolo, Gresti, Paolo (ORCID:0000-0003-4767-0282), P. Gresti, S. Perrin, Ph. Vernay, M. Zenari, M.C. Gerard-Zai, Gresti, Paolo, and Gresti, Paolo (ORCID:0000-0003-4767-0282)

Published
2000

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