Online Training on Skin Cancer Diagnosis in Rheumatologists: Results from a Nationwide Randomized Web-Based Survey

International audiencePatients with inflammatory rheumatisms, such as rheumatoid arthritis, are more prone to develop skin cancers than the general population, with an additional increased incidence when receiving TNF blockers. There is therefore a need that physicians treating patients affected with inflammatory rheumatisms with TNF blockers recognize malignant skin lesions, requiring an urgent referral to the dermatologist and a potential withdrawal or modification of the immunomodulatory treatment. We aimed to demonstrate that an online training dedicated to skin tumors increase the abilities of rheumatologists to discriminate skin cancers from benign skin tumors. A nationwide randomized web-based survey involving 141 French rheumatologists was conducted. The baseline evaluation included short cases with skin lesion pictures and multiple choice questions assessing basic knowledge on skin cancers. For each case, rheumatologists had to indicate the nature of skin lesion (benign; premalignant/ malignant), their level of confidence in this diagnosis (10-points Likert scale), and the precise dermatological diagnosis among 5 propositions. Different scores were established. After randomization, only one group had access to the online formation consisting in 4 elearning modules on skin tumors, of 15 minutes each (online training group). After reevaluation, the trained and the non-trained group (control group) were compared. The primary end-point was the number of adequate diagnoses of the nature of the skin lesions. The mean number of adequate diagnosis for the benign versus premalignant/malignant nature of the lesions was higher in the online training group (13.4 vs. 11.2 points; p value <0.0001). While the other knowledge scores were also significantly higher, no statistical difference was observed on the level of self-confidence between the 2 groups. In conclusion, the online formation was effective to improve the rheumatologists' ability to diagnose skin cancer

The 2018 European heatwave led to stem dehydration but not to consistent growth reductions in forests

Heatwaves exert disproportionately strong and sometimes irreversible impacts on forest ecosystems. These impacts remain poorly understood at the tree and species level and across large spatial scales. Here, we investigate the effects of the record-breaking 2018 European heatwave on tree growth and tree water status using a collection of high-temporal resolution dendrometer data from 21 species across 53 sites. Relative to the two preceding years, annual stem growth was not consistently reduced by the 2018 heatwave but stems experienced twice the temporary shrinkage due to depletion of water reserves. Conifer species were less capable of rehydrating overnight than broadleaves across gradients of soil and atmospheric drought, suggesting less resilience toward transient stress. In particular, Norway spruce and Scots pine experienced extensive stem dehydration. Our high-resolution dendrometer network was suitable to disentangle the effects of a severe heatwave on tree growth and desiccation at large-spatial scales in situ, and provided insights on which species may be more vulnerable to climate extremes

Covariations between plant functional traits emerge from constraining parameterization of a terrestrial biosphere model

Aim: The mechanisms of plant trait adaptation and acclimation are still poorly understood and, consequently, lack a consistent representation in terrestrial biosphere models (TBMs). Despite the increasing availability of geo‐referenced trait observations, current databases are still insufficient to cover all vegetation types and environmental conditions. In parallel, the growing number of continuous eddy‐covariance observations of energy and CO2 fluxes has enabled modellers to optimize TBMs with these data. Past attempts to optimize TBM parameters mostly focused on model performance, overlooking the ecological properties of ecosystems. The aim of this study was to assess the ecological consistency of optimized trait‐related parameters while improving the model performances for gross primary productivity (GPP) at sites. Location: Worldwide. Time period: 1992–2012. Major taxa studied: Trees and C3 grasses. Methods: We optimized parameters of the ORCHIDEE model against 371 site‐years of GPP estimates from the FLUXNET network, and we looked at global covariation among parameters and with climate. Results: The optimized parameter values were shown to be consistent with leaf‐scale traits, in particular, with well‐known trade‐offs observed at the leaf level, echoing the leaf economic spectrum theory. Results showed a marked sensitivity of trait‐related parameters to local bioclimatic variables and reproduced the observed relationships between traits and climate. Main conclusions: Our approach validates some biological processes implemented in the model and enables us to study ecological properties of vegetation at the canopy level, in addition to some traits that are difficult to observe experimentally. This study stresses the need for: (a) implementing explicit trade‐offs and acclimation processes in TBMs; (b) improving the representation of processes to avoid model‐specific parameterization; and (c) performing systematic measurements of traits at FLUXNET sites in order to gather information on plant ecophysiology and plant diversity, together with micro‐meteorological conditions

Climate control of terrestrial carbon exchange across biomes and continents

Peer reviewe

Photosynthese, consommation en eau et modelisation de la production chez le palmier a huile (Elaeis guineensis Jacq)

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Développement d'un modèle forestier générique simulant les flux et les stocks de carbonne et d'eau dans le cadre des changements climatiques

Un modèle simulant les flux et les stocks de CO2 et H2O est décrit, paramétré, validé et amélioré à l échelle de la parcelle forestière et l extension spatiale à l échelle de la région est entreprise. L effet sur les flux simulés de l incertitude sur les paramètres d entrées est estimé. Chaque processus implémenté dans le modèle est ensuite évalué séparémment. Puis, le modèle est adapté à différents types d écosystèmes forestiers et validé de l heure à la décénnie par comparaison à des flux nets de carbone et a des croissances de bois mesurés. Pour améliorer le couplage eau carbone et la réponse de la photosynthèse au rayonnement, la résistance mésophyllienne au trajet du CO2 entre les stomates et les chloroplastes est implémentée. Pour améliorer la simulation de la croissance aérienne du bois, un modèle d allocation est développé pour les espèces décidues en utilisant deux sortes de contraintes fonctionnelles : l homéostasie de la quantité de réserves carbonées et les contraintes hydrauliques. Deux modules, l un simulant le LAI à partir de la concentration en réserves et l autre simulant la masse surfacique des feuilles à partir du rayonnement global, sont aussi développés et validés. Ensuite, l effet sur les flux de l aggrégation spatiale des principaux paramètres d entrées variant spatialement, est quantifié à l aide d une étude de sensibilité et de trois cas d étude à trois échelles différentes (de 1 à 1000 ha). Enfin, à l échelle du massif forestier, une relation linéaire entre le LAI moyen et le logarithme de l écart type du NDVI mesuré par télédétection, est mise en evidence et les bases théoriques de cette relation sont étudiées.A model simulating CO2 and H2O stocks and fluxes is described, parameterised, validated and improved at forestry stand scale and up scaling to the region is set about. The effect on simulated fluxes of the uncertainty on key input parameters is estimated. Each process implemented in the model is then separately evaluated. After that, the model is adapted to various forest ecosystems and validated from hours to decals by comparison with carbon fluxes and wood growth measurements. To improve the carbon water coupling and the response of foliar photosynthesis to irradiance, the mésophylle resistance for CO2 flux between stomata and chloroplasts is incorporated in the photosynthesis model. To improve the aerial wood growth simulation, an allocation scheme is developed for deciduous trees using two kinds of functional constraints: the carbohydrates homeostasis and the hydraulic equilibrium. Two models, one simulating the Leaf Area Index from carbohydrates content, the other simulating the Leaf mass per Area from absorbed irradiance by leaves, are also developed and validated. After that, the spatial aggregation effect of the key input parameters, spatially varying, on the simulated fluxes, is quantified using a sensitivity analysis and three study cases at three different scales (from 1 ha to 1000 ha). Lastly, at regional scale, a linear relationship between the average LAI and the logarithm of the standard deviation of NDVI measured by remote sensing is highlighted and the theoretical basis of this relationship is studied.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Etude du déterminisme des variations interannuelles des échanges carbonés entre les écosystèmes forestiers européens et l atmosphère (une approche basée sur la modélisation des processus)

ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Age-related variation in carbon allocation at tree and stand scales in beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.) using a chronosequence approach

International audienceTwo types of physiological mechanisms can contribute to growth decline with age: (i) the mechanisms leading to the reduction of carbon assimilation (input) and (ii) those leading to modification of the resource economy. Surprisingly, the processes relating to carbon allocation have been little investigated as compared to research on the processes governing carbon assimilation. The objective of this paper was thus to test the hypothesis that growth decrease related to age is accompanied by changes in carbon allocation to the benefit of storage and reproductive functions in two contrasting broad-leaved species: beech (Fagus sylvatica L.) and sessile oak (Quercus petraea (Matt.) Liebl.). Age-related changes in carbon allocation were studied using a chronosequence approach. Chronosequences, each consisting of several even-aged stands ranging from 14 to 175 years old for beech and from 30 to 134 years old for sessile oak, were divided into five or six age classes. In this study, carbon allocations to growth, storage and reproduction were defined as the relative amount of carbon invested in biomass increment, carbohydrate increment and seed production, respectively. Tree-ring width and allometric relationships were used to assess biomass increment at the tree and stand scales. Below-ground biomass was assessed using a specific allometric relationship between root: shoot ratio and age, established from the literature review. Seasonal variations of carbohydrate concentrations were used to assess carbon allocation to storage. Reproduction effort was quantified for beech stands by collecting seed and cupule production. Age-related flagging of biomass productivity was assessed at the tree and stand scales, and carbohydrate quantities in trees increased with age for both species. Seed and cupule production increased with stand age in beech from 56 gC m−2 year−1 at 30 years old to 129 gCm−2 year−1 at 138 years old. In beech, carbon allocation to storage and reproductive functions increased with age to the detriment of carbon allocation to growth functions. In contrast, the carbon balance between growth and storage remained constant between age classes in sessile oak. The contrasting age-related changes in carbon allocation between beech and sessile oak are discussed with reference to the differences in growing environment, phenology and hydraulic properties of ring-porous and diffuse-porous species

Etude de l'allocation de carbone chez le jeune chêne et le hêtre en fonction l'âge et de la fertilité : approche expérimentale et modélisation

National audienc