Journal of Next-Generation Research 5.0
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Thermal and exhumation histories of the northern subalpine chains (Bauges and Bornes-France): evidence from forward thermal modeling coupling clay mineral diagenesis, organic maturity and carbonate clumped isotope (Δ47) data.
No full text19 pagesInternational audienceAssessing the thermal evolution of sedimentary basins over time is a major aspect of modern integrated basin analysis. While the behavior of clay minerals and organic matter with increasing burial is well documented in different geological and thermal settings, these methods are often limited by the temperature ranges over which they can be precisely applied and by the available material. Here, we explore the emergent Δ47 clumped isotope geospeedometry (based on the diffusional redistribution of carbon and oxygen isotopes in the carbonate lattice at elevated temperatures) to refine time‐temperature paths of carbonate rocks during their burial evolution. This study provides a reconstruction of the thermal and exhumation history of the Upper Cretaceous thrust belt series in the western subalpine massifs (Bauges and Bornes, French Alps) by a new approach combining for the first time available data from three independent geothermometers. The investigated area presents two zones affected by contrasting thermal histories. The most external zone has undergone a relatively mild thermal history (T 160–180°C) that induced widespread clay mineral diagenetic transformations (progressive illitization from R0 to R1 and R3 illite‐smectite mixed‐layers), organic matter maturation (oil window) and Δ47 thermal resetting with apparent equilibrium temperatures above 160°C. The three employed geothermal indicators conjointly reveal that the investigated Upper Cretaceous rocks have suffered a wide range of burial temperatures since their deposition, with a thermal maximum locally up to 160–180°C. High temperatures are associated with the tectonic emplacement of up to 4 km of prealpine nappes in the northern part of the studied area. Finally, a forward thermal modeling using Δ47, vitrinite reflectance and clay mineral data, is attempted to precisely refine the burial and exhumation histories of this area
Un dispositif pour les enseignants de FLE des universités angolaises
No full textInternational audienceThis contribution, which converges on comparative didactics, focuses on the description of generic and specific dimensions, knowledge and practices (Mercier, Schubauer-Léoni & Sensevy, 2000) from the videographies that will allow us to describe the classroom activities by focusing on both the flow of knowledge and, above all, the analysis of the professional gestures of the four FLE professors of two university institutions (Group A and Group B). The result showed that Group A teachers appear to have difficulty with their B congener who received the FLE training. This didactic analysis will allow us to find answers to the difficulties in the teaching activity and allow the learners to be actors of their own learning.La présente contribution, converge vers la didactique comparée et porte sur la description des dimensions génériques et spécifiques, sur le savoir et les pratiques (Mercier, 2000, Schubauer-Léoni & Sensevy, 2000) à partir des vidéographies qui nous permettront de décrire les activités de classe en nous intéressant à la fois sur la circulation des savoirs et surtout l'analyse des gestes professionnels des quatre professeurs du FLE de deux institutions universitaires (Groupe A et groupe B). Le résultat a démontré que les professeurs du groupe A semblent avoir de difficulté par rapport à leur congénère de B qui ont reçu la formation du FLE. Cette analyse didactique nous permettra de trouver des réponses aux difficultés dans l'activité enseignante et permettre aux apprenants d'être des acteurs de leurs propres apprentissages
Reply to Desmond F. Lascelles’ comment on “Tyler Warchola, Stefan V. Lalonde, Ernesto Pecoits, Konstantin von Gunten, Leslie J. Robbins, Daniel S. Alessi, Pascal Philippot, Kurt O. Konhauser. Petrology and geochemistry of the Boolgeeda iron formation, Hamersley Basin, Western Australia. Precambrian Research, (2018) 316: 155–173”
No full textInternational audienceWhile we appreciate Lascelles’ interest in our work, we find most of the points raised to be either poorly-supported or arising from a significant misunderstanding
Vertical land motion in the Southwest and Central Pacific from available GNSS solutions and implications for relative sea levels
No full textInternational audienceS U M M A R Y Coastal populations are impacted by relative sea level variations, which consist both of absolute sea level variations and of vertical land motions. This paper focuses on the Southwest and Central Pacific region, a recognized vulnerable region to sea level rise and where a large range of vertical land motion dynamics is observed. We analyse vertical displacement rates obtained from Global Navigation Satellite Systems (GNSS) by different analysis centres. We study the role played by modelled parameters, such as step discontinuities (due to equipment changes, earthquakes, etc.), in the position time-series analysis. We propose a new modelling approach based on a joint inversion of GNSS position time-series from different analysis centres. The final uncertainty on the vertical land motion rates is estimated as a combination of the uncertainty due to the GNSS data processing itself and the uncertainty due to the stability of the reference frame in which the GNSS data are expressed. We find that the dominant trend in the Southwest and Central Pacific is a moderate subsidence, with an average rate of −1.1 mm yr-1 , but significant variations are observed, with displacement rates varying from an uplift of 1.6 ± 0.3 mm yr-1 to a subsidence of −5.4 ± 0.3 mm yr-1. Taking into account the geodynamic context, we assess, for each station, the relevance of current estimates of linear vertical displacement rate and uncertainty for forecasting future coastal sea levels
Couvert forestier et distribution de Pan paniscus dans la Réserve Naturelle de Sankuru, RD Congo
No full textInternational audienceIl y a plusieurs années, l’accès aux divers points du paysage Salonga-Lukenie-Sankuru était extrêmement difficile, voire impossible. Cette difficulté constituait un handicap dans l’obtention de données de base, ainsi que le contrôle et le suivi de la gestion des ressources naturelles dans ce plus grand bloc des forêts inconnues en R.D. Congo. La Réserve Naturelle de Sankuru (RNSA), fait partie de ce paysage. Elle est située au centre du pays, dans la partie Nord de la province de Sankuru, à -2,56° de latitude et 24,15° de longitude, à l’Ouest du paysage Tshuapa-Lomami-Lualaba (TL2).Au moyen de la télédétection, du Système d’Informations Géographiques (SIG) et d’enquêtes auprès des populations locales, les recherches ont été focalisées sur la collecte des données et l’établissement des cartes de base pour le suivi et la gestion. La mise à disposition des images satellites Sentinel 2, SPOT 5, 6 et 7 par l’IGN (Institut Géographique National) et de Landsat 8 téléchargées, a contribué significativement à l’obtention des résultats présentés, notamment des informations cartographiques sur l’état du couvert forestier et sur les actuels et anciens emplacements des espèces phares telles que le bonobo (Pan paniscus) et l’okapi (Okapia johnstoni). Ce travail donne aux gestionnaires un aperçu de ce qu’est devenu l’aire protégée de Sankuru plus de dix ans après sa création.Les résultats obtenus montrent que la présence de bonobo est faible sur la grande partie de la RNSA, seule la chefferie de Djonga présente des signes d’une forte concentration de cette espèce. Dans les mosaïques champs-villages, sa présence est nulle. L’okapi est également signalé dans cette même chefferie.Par rapport à l’occupation du sol, près de 81% de la RNSA est couvert par la forêt, dont 54 % par une forêt dense humide et 26,4% par la forêt secondaire. L’espace non forestier est occupé par la mosaïque champs-villages, la savane et le sol nu représentant respectivement 14,2 %; 1,6 % et 3,5 %. Plusieurs villages sont implantés au sein de la réserve et constituent une difficulté pour la gestion et la conservation de la biodiversité présente dans cette aire protégée
A Land Use/Land cover on the small Indian Ocean islands, an example of its use with the study of vector-borne diseases
No full textInternational audienceThe southwestern Indian Ocean comprises numerous islands of less than 3000 sq km (Comoros, Seychelles, Mascarene Islands). These small island territories have very fragmented and diversified landscapes. Satellite imagery and landcover products at low and medium spatial resolution (usually from 4 kilometers to 250 meters) are not or poorly suited to the study of these areas. Therefore, we have developed a land use product, called Homisland-IO, based on the analysis of high spatial resolution images acquired by the SPOT 5 satellite between December 2012 and July 2014 and produced at the SEAS-OI Station. We used an object-based image analysis method to identify the 11 major classes of land cover / land use of these tropical islands. This methodology together with a good knowledge of the field has enabled us to achieve an overall accuracy of 86%, making it an operational product. These products have already been used in various projects, including epidemiology and health geography (Lept-OI, TROI, ISSE-Mayotte, etc) to describe the distribution and habitat of some vectors of diseases (mainly mosquitoes and rodents), a necessary condition for analyzing the risk of transmission of these diseases to humans
Multi-temporal airborne structure-from-motion on caldera rim: Hazard, visitor exposure and origins of instabilities at Piton de la Fournaise
No full textInternational audiencePiton de la Fournaise is one of the world's most active and visited volcanoes. Its summit crater (Cratère Dolomieu), the main tourist attraction, underwent a major caldera collapse in 2007 and its rim is not yet stabilized. In order to assess the caldera rim instability risk for visitors, we followed its structural evolution from 2007 to 2015. Using aerial photogrammetry campaigns, we mapped the unstable sites very precisely, carried out a quantitative analysis of the temporal evolution of these instabilities, and assessed the risks for visitors. Considering the 2008-2015 period, four sites close to the crater's edge showed significant horizontal ground motion (0.5-2 m), fracture widening (average of 0.3-0.56 m) and large-scale mass wasting volumes (total of 1.8+0.1 Â 10 6 m 3). We infer two different processes at work: (1) to the west and north, toppling of the basalt units occurs after periods of fracture widening due to the combined effect of magmatic intrusions and long-term inflation/deflation cycles; (2) to the south and east, parts of the caldera rim slowly slide towards the caldera centre, with significant accelerations during periods of enhanced volcanic activity (in 2008-2010 and 2014-2015). The official observation platform is the most stable zone to overlook the Cratère Dolomieu. By contrast, the most frequently visited area of the rim (northwest) outside the official platform is also the most unstable
Homolytic and heterolytic cleavage of beta-ether linkages in hardwood lignin by Steam Explosion
No full textInternational audienceSteam explosion lignin (SEL) was extracted with ethanol from steam exploded hardwood (okoumé, Aucoumea klaineana Pierre) pretreated at various severities after neutral or acidic impregnation. The SELs were subjected to a structural characterization by 2D HSQC NMR, 31P NMR, SEC and compared to Milled Wood Lignin (MWL). A strong decrease in the -O-4 content is observed with increasing steam explosion severity accompanied with a gradual increase in molecular mass. C-oxydized S units (S’, Hibbert’s ketones) were quantified by NMR and used as a marker of the hydrolytic mechanism as well as naphthol used as a carbonium ion scavenger. It has been observed that mixed reactions of hydrolysis and homolysis are involved but the SEL is mainly cleaved homolytically, favouring recondensation through radical coupling even at low reaction severity. However, acidic pre-impregnation of wood prior to steam explosion enhanced the carbonium ion pathway
Modèle décisionnel multi-niveaux et générique pour les applications de e- gouvernance dans le domaine éducatif Multi-level and generic decisional model for e-governance applications in the educational field
No full textThis article presents the mechanisms to create a generic platform for decision makers to implement rapid management models, with a multi-scale and multi-level stratification of education, including basic education, secondary and higher education, while minimizing the risk of errors, so as to increase their efficiency in the governance field. We will identify beforehand the various active and passive element involved in an education system, considered here as the model input parameters and the various interactions between them. Then we list the specific objectives and outputs considered in the model. We will build on the analysis and knowledge management techniques to develop a multi-level decision model incorporating input parameters and expected or desired outputs for better decision making. The developed model will be based on a formal language that we define. This work will help to solve the difficulties that governments sometimes face in optimizing and taking decision regarding construction of schools or universities in various localities, assignment of teachers or non-teaching staff in an institution, training of these as needed, allocation of teaching materials, benches and laboratory equipment. It is for us to truly put technology at the service of governance in education, and development in general.Cet article présente les mécanismes de création d'une plateforme générique permettant aux décideurs de mettre en oeuvre des modèles de pilotage rapide, avec une stratification multi-échelle et multi-degré du secteur de l'éducation, couvrant l'éducation de base, le secondaire et le supérieur, tout en minimisant les risques d'erreurs, de manière à accroitre leur efficacité en matière de gouvernance dans le domaine. Nous allons préalablement recenser les différents éléments actifs intervenant dans un système éducatif, considérés ici comme les différents niveaux du modèle, ainsi que les différentes interactions entre ces derniers. Ensuite, nous répertorierons les objectifs spécifiques à atteindre. Nous nous appuierons sur les Techniques d'analyse et de gestion des connaissances, pour développer un modèle décisionnel multi-niveaux intégrant les niveaux et les objectifs à atteindre, pour une meilleure prise de décision. Ce travail contribuera à résoudre les difficultés que les gouvernements rencontrent parfois dans l'optimisation de la prise de décision en matière de construction des établissements scolaires ou d'Universités dans diverses localités, d'affectation des enseignants ou du personnel non enseignant dans un établissement, de formation de ces derniers en fonction des besoins, etc…. Il s'agit pour nous de mettre véritablement la technologie au service de la gouvernance en matière d'éducation, et du développement en général
