The DACAPO-PESO campaign: Dynamics, Aerosol, Cloud and Precipitation Observations in the Pristine Environment of the Southern Ocean: An overview

This article gives an overview of the DACAPO-PESO field experiment, which has taken place in Punta Arenas, Chile, from November 2018 to November 2021, and showcases first exciting research results that have already emerged from it.In diesem Artikel wird ein Überblick über das DACAPO-PESO Experiment gegeben, welches von November 2018 bis November 2021 in Punta Arenas, Chile, stattgefunden hat. Außerdem werden erste spannende Forschungsergebnisse vorgestellt, die bereits daraus gewonnen wurden

Can physiological endpoints improve the sensitivity of assays with plants in the risk assessment of contaminated soils?

Site-specific risk assessment of contaminated areas indicates prior areas for intervention, and provides helpful information for risk managers. This study was conducted in the Ervedosa mine area (Bragança, Portugal), where both underground and open pit exploration of tin and arsenic minerals were performed for about one century (1857-1969). We aimed at obtaining ecotoxicological information with terrestrial and aquatic plant species to integrate in the risk assessment of this mine area. Further we also intended to evaluate if the assessment of other parameters, in standard assays with terrestrial plants, can improve the identification of phytotoxic soils. For this purpose, soil samples were collected on 16 sampling sites distributed along four transects, defined within the mine area, and in one reference site. General soil physical and chemical parameters, total and extractable metal contents were analyzed. Assays were performed for soil elutriates and for the whole soil matrix following standard guidelines for growth inhibition assay with Lemna minor and emergence and seedling growth assay with Zea mays. At the end of the Z. mays assay, relative water content, membrane permeability, leaf area, content of photosynthetic pigments (chlorophylls and carotenoids), malondialdehyde levels, proline content, and chlorophyll fluorescence (Fv/Fm and ΦPSII) parameters were evaluated. In general, the soils near the exploration area revealed high levels of Al, Mn, Fe and Cu. Almost all the soils from transepts C, D and F presented total concentrations of arsenic well above soils screening benchmark values available. Elutriates of several soils from sampling sites near the exploration and ore treatment areas were toxic to L. minor, suggesting that the retention function of these soils was seriously compromised. In Z. mays assay, plant performance parameters (other than those recommended by standard protocols), allowed the identification of more phytotoxic soils. The results suggest that these parameters could improve the sensitivity of the standard assays

Images; quels services, quels traitements ? Problèmes de réalisations industrielles et de réseaux de télécommunications

Le choix des méthodes de traitement inter et intra image et les modes de réalisations techniques et technologiques dépendent des services à offrir, de l'infrastructure des réseaux de télécommunications et de leurs évolutions. Les différents services examinés dans le document se répartissent en quatre grandes catégories : - Télédistribution de programmes avec ou sans interactivité. - Dialogue avec vision des locuteurs; visiophonie, visioconférence. - Aide à la communication par transmission d'images fixes. - Télésurveillance visuelle, La qualité de l'image offerte peut varier en fonction du service, se mesure en termes de définition, de colorimétrie, de respect du mouvement et est liée au temps de transmission, donc aux supports de télécommunications en termes de bande passante et (ou) de débits binaires offerts. Une comparaison est effectuée entre différents procédés de traitement en fonction de la qualité souhaitée, du temps d'exécution, des technologies utilisables, de la complexité, de l'immunité au bruit et de la sensibilité aux erreurs. Cette comparaison porte en particulier sur les traitements par DPCM et transformées, les procédés de rafraîchissement conditionnel et systématique

Neutral donor bound excitons studied by selective photoluminescence in wurtzite GaN

Selective photoluminescence experiments have been used to analyse the neutral donor bound exciton spectra in n type wurtzite GaN epitaxial layers deposited on 6H-SiC, Al2O3 and GaN substrates, In heterostructure layers, the existence of residual strain distributions make possible the observation of resonant sharp lines due to the recombination of bound excitons selectively created in excited states. It is shown that the excited states consist of rotational states of the hole belonging to the A valence band in GaN/sapphire and in homolayers. In GaN/SiC both A and B valence band states are involved