Theia Snow collection: high-resolution operational snow cover maps from Sentinel-2 and Landsat-8 data

The Theia Snow collection routinely provides high-resolution maps of the snow-covered area from Sentinel-2 and Landsat-8 observations. The collection covers selected areas worldwide, including the main mountain regions in western Europe (e.g. Alps, Pyrenees) and the High Atlas in Morocco. Each product of the Theia Snow collection contains four classes: snow, no snow, cloud and no data. We present the algorithm to generate the snow products and provide an evaluation of the accuracy of Sentinel-2 snow products using in situ snow depth measurements, higher-resolution snow maps and visual control. The results suggest that the snow is accurately detected in the Theia snow collection and that the snow detection is more accurate than the Sen2Cor outputs (ESA level 2 product). An issue that should be addressed in a future release is the occurrence of false snow detection in some large clouds. The snow maps are currently produced and freely distributed on average 5&thinsp;d after the image acquisition as raster and vector files via the Theia portal (https://doi.org/10.24400/329360/F7Q52MNK).</p

Microbiological and chemical monitoring of Marsala base wine obtained by spontaneous fermentation during large-scale production

The present work was undertaken to evaluate the effect of the natural winemaking on the microbial and chemical composition of Marsala base wine. To this purpose, a large-scale vinification process of Grillo grape cultivar was monitored from harvesting to the final product. Total yeasts (TY) showed a rapid increase after must pressing and reached values almost superimposable to those registered during the conventional winemakings. Lactic acid bacteria (LAB) were registered at the highest levels simultaneously to yeast growth at the beginning of the process. Saccharomyces cerevisiae was the species found at the highest concentrations in all samples analysed. Several strains (n= 16) was registered at high levels during the alcoholic fermentation and/or aging of wine; only two of them were detected on the grape surface. Lactobacillus plantarum was the LAB species most frequently isolated during the entire vinification process. Ethanol content was approximately 14% (v/v) at the end of vinification. The value of pH did not greatly vary during the process and the volatile acidity (VA) was detected at low concentrations during the entire transformation. The concentration of malic acid rapidly decreased during the AF; on the other hand, lactic acid showed an irregular trend during the entire process. trans-caffeil tartaric acid was the most abundant hydroxycinnamoyl tartaric acid and volatile organic compounds (VOC) were mainly represented by isoamylic alcohol and isobutanol

An Induced Mutation in Tomato eIF4E Leads to Immunity to Two Potyviruses

BACKGROUND: The characterization of natural recessive resistance genes and Arabidopsis virus-resistant mutants have implicated translation initiation factors of the eIF4E and eIF4G families as susceptibility factors required for virus infection and resistance function. METHODOLOGY/PRINCIPAL FINDINGS: To investigate further the role of translation initiation factors in virus resistance we set up a TILLING platform in tomato, cloned genes encoding for translation initiation factors eIF4E and eIF4G and screened for induced mutations that lead to virus resistance. A splicing mutant of the eukaryotic translation initiation factor, S.l_eIF4E1 G1485A, was identified and characterized with respect to cap binding activity and resistance spectrum. Molecular analysis of the transcript of the mutant form showed that both the second and the third exons were miss-spliced, leading to a truncated mRNA. The resulting truncated eIF4E1 protein is also impaired in cap-binding activity. The mutant line had no growth defect, likely because of functional redundancy with others eIF4E isoforms. When infected with different potyviruses, the mutant line was immune to two strains of Potato virus Y and Pepper mottle virus and susceptible to Tobacco each virus. CONCLUSIONS/SIGNIFICANCE: Mutation analysis of translation initiation factors shows that translation initiation factors of the eIF4E family are determinants of plant susceptibility to RNA viruses and viruses have adopted strategies to use different isoforms. This work also demonstrates the effectiveness of TILLING as a reverse genetics tool to improve crop species. We have also developed a complete tool that can be used for both forward and reverse genetics in tomato, for both basic science and crop improvement. By opening it to the community, we hope to fulfill the expectations of both crop breeders and scientists who are using tomato as their model of study

Theia Snow collection: High-resolution operational snow cover maps from Sentinel-2 and Landsat-8 data

The Theia Snow collection routinely provides high-resolution maps of the snow-covered area from Sentinel-2 and Landsat-8 observations. The collection covers selected areas worldwide, including the main mountain regions in western Europe (e.g. Alps, Pyrenees) and the High Atlas in Morocco. Each product of the Theia Snow collection contains four classes: snow, no snow, cloud and no data. We present the algorithm to generate the snow products and provide an evaluation of the accuracy of Sentinel-2 snow products using in situ snow depth measurements, higher-resolution snow maps and visual control. The results suggest that the snow is accurately detected in the Theia snow collection and that the snow detection is more accurate than the Sen2Cor outputs (ESA level 2 product). An issue that should be addressed in a future release is the occurrence of false snow detection in some large clouds

Chemical Reaction Effects on Wall Heat Flux in Liquid Rocket Thrust Chambers

Cooling of thrust chamber walls to allowable solid material temperature induces near wall recombination which may add a non-negligible contribution to the heat transfer from the hot gas to the wall. In this study, the role of near wall recombination is studied by suitable numerical analyses. Numerical results are compared to literature experimental data of wall heat flux in subscale calorimetric thrust chambers for both oxygen/methane and oxygen/hydrogen propellant combination. Then, a parametric analysis is carried out varying chamber pressure, wall temperature and propellant combination. This study highlights that oxygen/methane combustion products are more subject to near wall recombination phenomena. They provide an increase of wall heat flux up to 30% with respect to the frozen value, whereas in the case of oxygen/hydrogen this value does not exceed 10%. Hence, reacting flow simulation is strongly recommended in case of methane fueled thrust chamber analysis, whereas in hydrogen fueled thrust chambers, especially at very high chamber pressure, the difference between reacting and frozen flow model is very small