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Pollution des sols en ETMM à l'échelle d'un territoire en contexte industriel multi-sources
No full textNational audienceDans un contexte industriel historique dense couvrant un territoire vaste, présentant des contaminations croisées en ETMM dans les sols de surface, des outils spécifiques d'analyse à vocation de forensie environnementale ont été sélectionnés et mis en oeuvre pour l'établissement d'une Interprétation de l'Etat des Milieux (IEM), dans le but de déterminer les contributions des différentes activités en lien avec la qualité géochimique des sols environnants. Les outils retenus sont le traitement statistique et géostatistique des analyses menées sur la qualité des sols en 44 ETMM et en isotopie du Pb. La mise en oeuvre de ces outils a permis la remontée en paternité des pollutions en ETMM enregistrée dans les sols de surface à l'échelle du territoire et la définition des zones d'influence de chaque site industriel historiquement émetteur. Le traitement statistique et géostatistique ainsi que l'analyse de la signature isotopique en Pb dans les sols relèvent de la recherche fondamentale et nécessitent de faire appel à des experts. Dans le cas présent des chercheurs du CNRS ont été mis à contribution. Enfin, une stratégie spécifique doit être bâtie pour le traçage de source, en complément de la méthodologie nationale des site et sols pollués.</div
Vegetation and climate changes during the Early–Middle Pleistocene transition in the Eastern Mediterranean: A case study from Lake Acıgöl in Southwestern Anatolia
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Analyse didactique d'un jeu de rôles à destination des enseignants de l'école primaire
No full textRole play is a type of training situation that places trainees in a context close to classroom practice. In this text, we carry out a didactic study of role play to identify and analyze the choices available to the trainer, and the potential impact of these choices on the knowledge at play during implementation. To this end, we have developed a methodology based on the dual status of the teaching task to which this type of training situation is associated. The analysis is carried out on a role play in the field of spatial structuring. It reveals didactic variables for training.Analyse didactique d'un jeu de rôles à destination des enseignants de l'école primaireRésumé. Le jeu de rôles est un type de situation de formation qui place les formés dans un contexte proche de l'exercice de la classe. Dans ce texte, nous en réalisons une étude didactique afin d'identifier et d'analyser les choix qui s'offrent au formateur ainsi que l'impact potentiel de ces choix sur les savoirs en jeu lors de la mise en oeuvre. Pour ce faire, nous développons une méthodologie basée sur un double statut de la tâche d'enseignement à laquelle est associé ce type de situation, et que nous mettons en lumière. L'analyse, réalisée sur un jeu de rôles dans le domaine de la structuration de l'espace, met au jour des variables didactiques de formation.</div
Les châtellenies, ou comment administrer la Savoie entre le XIIIe et le XVe siècle.
No full textNational audienceEntre le XIIIe et le XVe siècles, le Dauphiné et de la Savoie connaissent une période d’expansion territoriale sans précédent. À eux deux, ils dominent un espace de près de 60 000 km² allant du Jura à la Méditerranée et du Rhône au Pô. Ce vaste territoire est divisé en châtellenies, qui sont la base de l’organisation de l’espace régional comme du système administratif des deux principautés
From 1923 to 2023, a century of endemic malaria – Comoros can eliminate it?
No full textInternational audienceMalaria was first confirmed in Comoros in 1923 by Jean Raynal (Raynal, 1928), who in 1925 was appointed by the French colonial government to investigate a fatal epidemic in Grande Comore. Since then, malaria has become an endemic disease in the Comoros archipelago. In 2023, a century later, malaria remains a major health problem that the authorities are committed to eradicate. The aim of this demonstration is to retrace the evolution of malaria epidemiology from 1923 to 2023 in order to understand its decline and maintenance in Comoros. Thus, World Health Statistical Yearbooks and WHO World Malaria Reports, as well as the databases of the National Malaria Control Program (PNLP-Comores) were consulted to compile a database of malaria cases from 1923 to 2023. Using both historical and more recent sources of population data, the annual incidence of malaria was calculated for the three islands of the Union of Comoros. In parallel, data on various malaria control measures implemented during this period were recorded and used to examine their effects on the malaria evolution trend. The malaria epidemic of 1923 to 1925 caused over 2,500 deaths on Grande Comore alone. Malaria incidence averaged over 3,307 cases per 100,000 inhabitants between 1955 and 1976, less than 2,410 cases between 1993 and 1999, and over 7,360 cases between 2004 and 2009. From 2010 to 2017, incidence declined from 15,074 cases to less than 323 cases per 100,000 inhabitants, a 94% of reduction. However, since 2018, there has been a resurgence of malaria cases in Grande Comore, with incidence exceeding 1,000 cases per 100,000 inhabitants. This study showed how malaria has evolved in Comoros over a century, characterizing the effects of the control measures implemented: indoor residual spraying, mass distribution of insecticide-impregnated mosquito nets, mass treatment with Artequick, and improved diagnosis, care and treatment of patients. Comoros has been classified as a country in the malaria elimination phase, but definitive elimination remains a major challenge
Vulnerability of benthic macroinvertebrates facing with multi-stressors exposures: a walk with Diptera chironomidae from high altitude lakes to urban streams
No full textInternational audienc
GEOV2-AVHRR: Continuous and consistent time series of global leaf area index and fraction absorbed PAR from 1981 to 2022
No full textInternational audienceLong-term time series of global leaf area index (LAI) and fraction of absorbed photosynthetic active radiation (FAPAR) are required for characterizing vegetation dynamics in global change studies. The recently developed Copernicus Land Monitoring Service GEOV2-CLMS products were demonstrated to outperform other existing LAI and FAPAR products in terms of completeness, temporal smoothness, consistency across variables and accuracy. However, these GEOV2-CLMS products are derived from the SPOT/VGT and PROBA-V constellation with temporal coverage from 1999 to 2020 which limits its applicability for global change studies. We present here anadaptation of the GEOV2-CLMS algorithm to AVHRR to extend these time series and generate long-term global vegetation products from July 1981 to December 2022. The GEOV2-AVHRR algorithm was specifically designed to maximize the temporal consistency over the successive AVHRR sensors on board NOAA and MetOp-B satellites while keeping high agreement with GEOV2-CLMS products. Neural networks first transform AVHRR surface reflectance into LAI and FAPAR values at the daily time step. The daily estimates are then filtered, smoothed, gap filled and composited every 10-day. GEOV2-AVHRR showed accuracy error between 0.2 and 0.3 LAI and ~ 0.03 FAPAR and uncertainty <1 LAI and ~ 0.10–0.15 for woody and non-woody sites of both DIRECT2.1 and GBOV V3 datasets. GEOV2-AVHRR agreed well with GEOV2-CLMS (MODIS): 92 % (76 %) of land pixels are within ±max(20 %, 0.5) LAI and 71 % (34 %) within ±max(10 %, 0.05) FAPAR uncertainty requirements. The gap filling and temporal filters applied in GEOV2-AVHRR proved effective in improving the completeness (only 1 % of missing data) and temporal precision (smoothness) of LAI and FAPAR time series as compared to MODIS. The intra-annual consistency of GEOV2-AVHRR highly agree with GEOV2-CLMS, indicating it is mostly driven by the algorithm. On the contrary, the inter-annual consistency of LAI and FAPAR datasets appears to be very sensitive to the consistency of the input surface reflectance. GEOV2-AVHRR showed high stability as evaluated with MODIS LAI/FAPAR and improves the stability of GEOV2-CLMS. Some residual inter-annual inconsistencies from the transition to sensors are observed for GEOV2-AVHRR as well as for other long term AVHRR datasets (i.e. GIMMS, GLASS and C3S). GEOV2-AVHRR shows overall greening trends in ~70 % (~50 % significant at p < 0.05) of land pixels, and the magnitude and spatial pattern of trends highly agree with those of GIM
Influence of thinning intensity on sexual versus vegetative regeneration of Quercus pubescens Willd. coppices
No full textInternational audienc
BioRev’Aix, Biodiversité et réseau viaire à Aix-en-Provence: Interroger la morphologie urbaine à travers l'écologie du tronçon de rue
No full textInternational audienceMatrice première de constitution et d’évolution des tissus urbains, le réseau viaire constitue un élément clé de la morphogenèse urbaine. Dans un contexte de transition écologique, le projet BioRev-Aix (Biodiversité et Réseau viaire à Aix-en-Provence) interroge la capacité de la rue à être support de fonctionnements urbanistiques et écologiques. Croisant urbanisme et écologie, la recherche s’appuie sur le "tronçon de rue” comme unité d’analyse originale pour modéliser la morphologie urbaine et inventorier sa biodiversité (malacofaune, flore spontanée, écureuil roux). Cet élément permet d’appréhender les différentes formes de natures urbaines de manière multiscalaire et contextuelle, associant la prise en compte de la rue comme lieu/habitat et comme lien/corridor. Le tronçon de rue apparaît alors comme un élément de recherche-action prometteur pour l’analyse des rapports entre morphologie urbaine et biodiversité
The Role of Barrier Reef Protection to Storm Surge During Tropical Cyclones in a Narrow Lagoon, New Caledonia, South West Pacific
No full textInternational audiencePacific islands are exposed to coastal hazards, particularly storm surges resulting from low pressure, extreme winds, and waves. While coral reefs naturally protect shorelines from incident waves, the diversity of reef geomorphologies induce various coastal responses, complicating hazard prediction based on offshore conditions. Understanding lagoon storm surge dynamics is therefore crucial for developing adaptation strategies to address global warming and sea-level rise. This study investigates the storm surge response of the narrow and shallow lagoon of Poe in New Caledonia using the SCHISM-SWAN coupled circulation-wave numerical model under tropical cyclone conditions. A retrospective of the 2019 cyclonic season shows that maximum storm surge is concentrated in the narrowest part of the lagoon, where human infrastructures are located, increasing exposure to extreme water levels. Modifying the reef structure to a more irregular form reveals that macro-scale reef features can mitigate wave setup intensity. Additionally, water depth variations over the reef crest significantly affect wave setup, with up to 30% difference between high and low tides. A broader generalization based on 258 synthetic cyclone tracks highlights that within the lagoon, wave setup accounts for approximately 70% of the storm surge, rising to 90% during the most extreme event. These results showing that the wave contribution is essential for accurate storm surge prediction. The findings provide critical insights for improving coastal hazard assessment, land use planning, and resilience strategies in reef island environments facing climate change