The tetrazolium reduction method for assessing the viability of individual bacterial cells in aquatic environments : improvements, performance and applications

Le système transporteur d'électron des bactéries réduit le 2-(p-iodophenyl) -3(p-nitrophenyl) -5-phenyltetrazolium chloride (INT) en INt formazan qui est détecté dans les cellules par un précipité opaque. Un nouveau protocole est proposé, qui améliore la méthode, pour les bactéries des milieux aquatiques, la rendant à la fois plus rapide, sensible et fiable. (Résumé d'auteur

Influence of composition on the thermal stability of ceria-zirconia mixed oxides

International audienceCeria-zirconia mixed oxides are essential components in the three-way catalytic converters for automotive exhaust gas treatment and they must offer a good thermal stability in severe operating conditions. It is thus important to have a precise knowledge of the influence of the composition of the mixed oxide on the textural and structural properties of the catalytic materials. The behaviour of ceria-zirconia high surface area materials of nominal composition between CeO2 and Ce0.50Zr0.50O2 either bare or loaded with low ..

Comparing hydroacoustic fish stock estimates in the pelagic zone of temperate deep lakes using three sound frequencies (70, 120, 200 kHz)

Several decades of research have led to the acceptance of hydroacoustics as a reliable measurement method to monitor fish population in lakes, but full standardisation and intercalibration are still lacking. The aim of this study was to investigate the effect of sound frequency on acoustic parameters, such as volume backscattering strength, target strength, and the estimation of fish abundance. Data were recorded in situ using 3 frequencies (70, 120, 200 kHz) simultaneously in 2 different lakes. The results among the frequencies were compared and statistically tested. Data from the 70 and 120 kHz frequencies yielded similar results, but the 200 kHz echosounder estimates in temperate lakes seemed different, especially in cases of high fish abundance, which is typical of eutrophic ecosystems. This work indicates that the abundance estimates of fish populations in temperate lakes based on 200 kHz frequency may differ from results obtained using lower frequencies, and that further study is needed

Spectrum standardization for laser-induced breakdown spectroscopy measurements

This paper presents a spectra normalization method for laser-induced breakdown spectroscopy (LIBS) measurements by converting the recorded characteristic line intensity at varying conditions to the intensity under a standard condition with standard plasma temperature, degree of ionization, and total number density of the interested species to reduce the measurement uncertainty. The characteristic line intensities of the interested species are first converted to the intensity at a fixed temperature and standard degree of ionization but varying total number density for each laser pulse analysis. Under this state, if the influence of the variation of plasma morphology is neglected, the sum of multiple spectral line intensities for the measured element can be regarded proportional to the total number density of the specific element, and the fluctuation of the total number density, or the variation of ablation mass, was compensated for by the application of this relationship. In the experiments with 29 brass alloy samples, the application of this method to determine Cu concentration shows a significant improvement over generally applied normalization method for measurement precision and accuracy. The average RSD value, average value of the error bar, R2, RMSEP, and average value of the maximum relative error were: 5.29%, 0.68%, 0.98, 2.72%, 16.97%, respectively, while the above parameter values for normalization with the whole spectrum area were: 8.61%, 1.37%, 0.95, 3.28%, 29.19%, respectively.Comment: LIBS; Normalization; quantitative measurement; plasma propert

The Science Performance of JWST as Characterized in Commissioning

This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures; https://iopscience.iop.org/article/10.1088/1538-3873/acb29

Identification of carbon dioxide in an exoplanet atmosphere

Carbon dioxide (CO2) is a key chemical species that is found in a wide range of planetary atmospheres. In the context of exoplanets, CO2 is an indicator of the metal enrichment (that is, elements heavier than helium, also called ‘metallicity’), and thus the formation processes of the primary atmospheres of hot gas giants. It is also one of the most promising species to detect in the secondary atmospheres of terrestrial exoplanets. Previous photometric measurements of transiting planets with the Spitzer Space Telescope have given hints of the presence of CO2, but have not yielded definitive detections owing to the lack of unambiguous spectroscopic identification. Here we present the detection of CO2 in the atmosphere of the gas giant exoplanet WASP-39b from transmission spectroscopy observations obtained with JWST as part of the Early Release Science programme. The data used in this study span 3.0–5.5 micrometres in wavelength and show a prominent CO2 absorption feature at 4.3 micrometres (26-sigma significance). The overall spectrum is well matched by one-dimensional, ten-times solar metallicity models that assume radiative–convective–thermochemical equilibrium and have moderate cloud opacity. These models predict that the atmosphere should have water, carbon monoxide and hydrogen sulfide in addition to CO2, but little methane. Furthermore, we also tentatively detect a small absorption feature near 4.0 micrometres that is not reproduced by these models

Abstracts from the 8th International Conference on cGMP Generators, Effectors and Therapeutic Implications

This work was supported by a restricted research grant of Bayer AG

Passe à poissons de Vongy. Synthèse 1998-2001

*INRA Station d'Hydrobiologie Lacustre, Thonon-Les-Bains Diffusion du document : INRA Station d'Hydrobiologie Lacustre, Thonon-Les-BainsNational audienc

Météorologie. Campagne 2000

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Passe à poissons de Vongy. Campagne 1998-2000

*INRA, Station d'Hydrobiologie Lacustre Thonon-les-Bains (FRA) Diffusion du document : INRA, Station d'Hydrobiologie Lacustre Thonon-les-Bains (FRA)National audienc