Étude expérimentale sur l'accumulation et la rétention du 134Cs par une microalgue planctonique, Selenastrum capricornutum Printz

Avec l'objectif de mieux connaître le comportement du césium radioactif et son transfert dans un écosystème naturel d'eau douce, une étude concernant une chaîne trophique du fleuve Tejo a été conduite dans le cadre du contrat (CCE) n° B16-0245-P et aussi du contrat (CCE) n° B16-B-198-P. Ce document présente l'étude de l'interaction eau-producteur primaire, Selenastrum capricomufum Printz, algue planctonique unicellulaire, en présence du 134Cs.Les essais de contamination de la microalgue ont été conduits en utilisant des cultures en milieu confiné et en phase de stabilisation de la croissance. Quand la composition chimique de l'eau de Fratel n'est pas modifiée, sauf en ce qui est de l'addition du radioélément, le facteur de concentration évalué est de (1,6 ±0,2)103 (rapporté au poids sec). Par ailleurs, quand il y a un enrichissement en plusieurs cations par l'addition d'un milieu nutritif, le facteur de concentration baisse à (1,5 ± 0,2)102. Dans tous les cas l'équilibre est atteint dans les premières 24 h.L'étude de la rétention a été réalisée en repiquant des microalgues, préalablement contaminées, dans l'eau du fleuve non radioactive et en les maintenant soit en milieu confiné, soit en milieu renouvelé une seule fois au bout d'un jour, ou plusieurs fois au cours de l'expérience. Comme les résultats obtenus dans ces trois conditions sont semblables, un modèle général exprimant la variation du pourcentage de rétention a pu étre établi :R (t) = 76,7 e-45,0 t + 20,1 e-1,28 t (t exprimé en jours)ce modèle met en évidence l'existence de deux périodes biologiques, respectivement Tb1 = 0,015 jours et Tb2 = 0,54 jours.Compte tenu de la dilution biologique due à la prolifération des algues unicellulaires au cours des expériences, la cinétique de désorption permet de faire l'hypothèse que le 134Cs est d'une part adsorbé sur les surfaces et d'autre part absorbé dans les cellules.For a better understanding of the radiocesium transfer in a freshwater ecosystem, a study concerning a simplified trophic chain from the Fratel dam, in the River Tejo, is being developed under the CEC contract n° B16-0245-P and also the CEC contract n° B16-B-198-P. In this paper is presented the study of the interaction water - primary producer (Selenastrum tapricornutum Printz, an unicellular planktonic algae) in the presence of 134Cs.The accumulation experiments were carried out in confined medium, during stabilization of the culture development. When the microalgae were cultivated in labelled river water, without any chemical change except for the addition of 134Cs, the evaluated concentration factor was CF = (1,6 ± 0,2)103, referred to dry weight. Otherwise, when the water was enriched by several cations by the addition of nutrients, the concentration factor was lower, CF = (1,6 ± 0,2)103. In every case, equilibrium was reached within the first 24 h.The retention was also carried out in river water and was studied through three parallel experiments : the labelled microalgae were maintained respectively in a confined medium, in a renewed medium with one single renewal made after 24 h's experiment, and in a renewed medium with renewals made at each sampling time. In every case, the 134Cs loss obeyed a two-differential equation and the results obtained were similar, namely concerning the biological half-lives (Tb1 = 0.015 days in every case and Tb2 respectively 0.53, 0.42 and 0.54 days); therefore a total model could be deduced :R (t) = 76,7 e-45,0 t + 20,1 e-128 t (t in days)showing two biological half-lives, which were Tb1 = 0.015 and Tb2 = 0.54 days.Taking into account the biological dilution due to the biomass increase during the experiments, the elimination kinetics suggests that 134Cs is on the one hand adsorbed on the cell surface and on the other band is absorbed intracellularly

ARIA digital anamorphosis : Digital transformation of health and care in airway diseases from research to practice

Digital anamorphosis is used to define a distorted image of health and care that may be viewed correctly using digital tools and strategies. MASK digital anamorphosis represents the process used by MASK to develop the digital transformation of health and care in rhinitis. It strengthens the ARIA change management strategy in the prevention and management of airway disease. The MASK strategy is based on validated digital tools. Using the MASK digital tool and the CARAT online enhanced clinical framework, solutions for practical steps of digital enhancement of care are proposed.Peer reviewe

ARIA digital anamorphosis: Digital transformation of health and care in airway diseases from research to practice

Digital anamorphosis is used to define a distorted image of health and care that may be viewed correctly using digital tools and strategies. MASK digital anamorphosis represents the process used by MASK to develop the digital transformation of health and care in rhinitis. It strengthens the ARIA change management strategy in the prevention and management of airway disease. The MASK strategy is based on validated digital tools. Using the MASK digital tool and the CARAT online enhanced clinical framework, solutions for practical steps of digital enhancement of care are proposed

Climate-induced changes in the suitable habitat of cold-water corals and commercially important deep-sea fishes in the North Atlantic

We used environmental niche modelling along with the best available species occurrence data and environmental parameters to model habitat suitability for key cold-water coral and commercially important deep-sea fish species under present-day (1951-2000) environmental conditions and to forecast changes under severe, high emissions future (2081-2100) climate projections (RCP8.5 scenario) for the North Atlantic Ocean (from 18°N to 76°N and 36°E to 98°W). The VME indicator taxa included Lophelia pertusa , Madrepora oculata, Desmophyllum dianthus, Acanela arbuscula, Acanthogorgia armata, and Paragorgia arborea. The six deep-sea fish species selected were: Coryphaenoides rupestris, Gadus morhua, blackbelly Helicolenus dactylopterus, Hippoglossoides platessoides, Reinhardtius hippoglossoides, and Sebastes mentella. We used an ensemble modelling approach employing three widely-used modelling methods: the Maxent maximum entropy model, Generalized Additive Models, and Random Forest. This dataset contains: 1) Predicted habitat suitability index under present-day (1951-2000) and future (2081-2100; RCP8.5) environmental conditions for twelve deep-sea species in the North Atlantic Ocean, using an ensemble modelling approach.  2) Climate-induced changes in the suitable habitat of twelve deep-sea species in the North Atlantic Ocean, as determined by binary maps built with an ensemble modelling approach and the 10-percentile training presence logistic (10th percentile) threshold. 3) Forecasted present-day suitable habitat loss (value=-1), gain (value=1), and acting as climate refugia (value=2) areas under future (2081-2100; RCP8.5) environmental conditions for twelve deep-sea species in the North Atlantic Ocean. Areas were identified from binary maps built with an ensemble modelling approach and two thresholds: 10-percentile training presence logistic threshold (10th percentile) and maximum sensitivity and specificity (MSS). Refugia areas are those areas predicted as suitable both under present-day and future conditions. All predictions were projected with the Albers equal-area conical projection centred in the middle of the study area. The grid cell resolution is of 3x3 km

ARIA digital anamorphosis: Digital transformation of health and care in airway diseases from research to practice

Digital anamorphosis is used to define a distorted image of health and care that may be viewed correctly using digital tools and strategies. MASK digital anamorphosis represents the process used by MASK to develop the digital transformation of health and care in rhinitis. It strengthens the ARIA change management strategy in the prevention and management of airway disease. The MASK strategy is based on validated digital tools. Using the MASK digital tool and the CARAT online enhanced clinical framework, solutions for practical steps of digital enhancement of care are proposed