Deep neural networks with transfer learning for forest variable estimation using sentinel-2 imagery in boreal forest

Estimation of forest structural variables is essential to provide relevant insights for public and private stakeholders in forestry and environmental sectors. Airborne light detection and ranging (LiDAR) enables accurate forest inventory, but it is expensive for large area analyses. Continuously increasing volume of open Earth Observation (EO) imagery from high-resolution (|BIAS%| = 0.8%). We found 3×3 pixels to be the optimal size for the sampling window, and two to three hidden layer DNNs to produce the best results with relatively small improvement to single hidden layer networks. Including CHM features with S2 data and additional features led to reduced relative RMSE (RMSE% = 28.6–30.7%) but increased the absolute value of relative bias (|BIAS%| = 0.9–4.0%). Transfer learning was found to be beneficial mainly with training data sets containing less than 250 field plots. The performance differences of DNN and random forest models were marginal. Our results contribute to improved structural variable estimation performance in boreal forests with the proposed image sampling and input feature concept

The nuclear and organellar tRNA-derived RNA fragment population in Arabidopsis thaliana is highly dynamic

In the expanding repertoire of small noncoding RNAs (ncRNAs), tRNA-derived RNA fragments (tRFs) have been identified in all domains of life. Their existence in plants has been already proven but no detailed analysis has been performed. Here, short tRFs of 19-26 nucleotides were retrieved from Arabidopsis thaliana small RNA libraries obtained from various tissues, plants submitted to abiotic stress or fractions immunoprecipitated with ARGONAUTE 1 (AGO1). Large differences in the tRF populations of each extract were observed. Depending on the tRNA, either tRF-5D (due to a cleavage in the D region) or tRF-3T (via a cleavage in the T region) were found and hot spots of tRNA cleavages have been identified. Interestingly, up to 25% of the tRFs originate from plastid tRNAs and we provide evidence that mitochondrial tRNAs can also be a source of tRFs. Very specific tRF-5D deriving not only from nucleus-encoded but also from plastid-encoded tRNAs are strongly enriched in AGO1 immunoprecipitates. We demonstrate that the organellar tRFs are not found within chloroplasts or mitochondria but rather accumulate outside the organelles. These observations suggest that some organellar tRFs could play regulatory functions within the plant cell and may be part of a signaling pathway.Cognat, Valerie Morelle, Geoffrey Megel, Cyrille Lalande, Stephanie Molinier, Jean Vincent, Timothee Small, Ian Duchene, Anne-Marie Marechal-Drouard, Laurence eng England 2016/12/03 06:00 Nucleic Acids Res. 2017 Apr 7;45(6):3460-3472. doi: 10.1093/nar/gkw1122.PMC538970

La montagne explorée, étudiée et représentée : évolution des pratiques culturelles depuis le xviiie siècle

Le Siècle des lumières, qui consacre l’ouverture des élites européennes à la modernité scientifique, est aussi celui qui pousse les mêmes sociétés vers les sommets et les glaciers des montagnes. Objet de fascination et non plus de crainte, la montagne apparaît, à la suite de Rousseau et Senancour, dans toute sa majesté, à la fois vierge, mystérieuse, repliée sur elle-même et porteuse d’un message d’universalité. Après avoir longtemps suscité peur et préjugés depuis l’Antiquité, la montagne est devenue au xviiie siècle un territoire de conquête et de découverte générant toute une mythologie et un imaginaire qui vont modifier le rapport des sociétés européennes avec le milieu des sommets. Le Congrès national des sociétés historiques et scientifiques rassemble chaque année universitaires, membres de sociétés savantes et jeunes chercheurs. Ce recueil est issu de travaux présentés lors du 142e Congrès sur le thème « Circulations montagnardes, circulations européennes »

Maternal gluten, cereal, and dietary fiber intake during pregnancy and lactation and the risk of islet autoimmunity and type 1 diabetes in the child

Background & aims: Maternal gluten intake in relation to child's risk of type 1 diabetes has been studied in few prospective studies considering the diet during pregnancy but none during lactation. Our aim was to study whether gluten, cereals, or dietary fiber in maternal diet during pregnancy and lactation is associated with the risk of islet autoimmunity or type 1 diabetes in the offspring. Methods: We included 4943 children with genetic susceptibility to type 1 diabetes from the Finnish Type 1 Diabetes Prediction and Prevention (DIPP) Study, born between 1996 and 2004. Maternal intake of gluten, different types of cereals, and dietary fiber were derived from a semi-quantitative validated food frequency questionnaire covering the eighth month of pregnancy and the third month of lactation. Children were monitored for islet autoantibodies up to age of 15 years and type 1 diabetes until year 2017. Risk of islet autoimmunity and clinical type 1 diabetes were estimated using Cox regression model, adjusted for energy intake, child's sex, HLA genotype, and familial diabetes. Results: Altogether 312 children (6.4%) developed islet autoimmunity at median age of 3.5 (IQR 1.7, 6.6) years and 178 children (3.6%) developed type 1 diabetes at median age of 7.1 (IQR 4.3, 10.6) years. Gluten intake during pregnancy was not associated with islet autoimmunity (HR 0.96; 95% CI 0.68, 1.35), per 1 g/MJ increase in intake nor type 1 diabetes (HR 0.96; 95% CI 0.62, 1.50) in the offspring. Higher barley consumption during lactation was associated with increased risk of type 1 diabetes (HR 3.25; 95% CI 1.21, 8.70) per 1 g/MJ increase in intake. Maternal intake of other cereals or dietary fiber was not associated with the offspring outcomes. Conclusions: We observed no association between maternal intake of gluten, most consumed cereals, or dietary fiber during pregnancy or lactation and the risk of islet autoimmunity or type 1 diabetes in children from a high-risk population

Travail et santé mentale : approches cliniques

International audienc

Comparison of polarimetric change detection methods on alos palsar images over finland

Six polarimetric change detection indices were tested on L band ALOS PALSAR data over Kuortane, Finland. Tests included quantitative evaluation of change indices compared to reference change maps, and qualitative evaluation by visual inspection. Results suggest an additional accuracy using fully polarimetric data in change detection. Contrast Ratio and the Wishart test gave the best results among the tested indices.</p

L'Hystérie sur scène. Des leçons de Charcot à l'enseignement de Freud et de Lacan: lectures et représentations contemporaines

International audienc

La métropole en projet, Identités et forces structurantes des territoires dans la construction de Pris Métropole

450 p