Journal of Next-Generation Research 5.0
Not a member yet
7559 research outputs found
Sort by
La démocratie locale en matière d’adaptation au changement climatique
No full textInternational audienceToday, it is clear that democracy and environment are linked. Whatever the issue, it appears necessary to integrate the citizen in any decision making affecting the environment. The issue of adaptation to climate change is a perfect example. Nevertheless, in this field, the way in which democracy operates could be improved.Il ne fait aucun doute aujourd’hui que démocratie et environnement sont liés. Quelle que soit la problématique envisagée, il apparaît nécessaire d’associer le citoyen à toute prise de décision en lien avec des questions d’environnement. La question de l’adaptation au changement climatique ne déroge pas à cette réalité. Néanmoins, la façon dont la démocratie est prise en compte en la matière reste perfectible
On the frequency spectra of the core magnetic field Gauss coefficients
No full textInternational audienc
Titanium isotopes as a tracer for the plume or island arc affinity of felsic rocks
No full textInternational audienceIndirect evidence for the presence of a felsic continental crust, such as the elevated 49 Ti/ 47 Ti ratios in Archean shales, has been used to argue for ongoing subduction at that time and therefore plate tectonics. However, rocks of intermediate to felsic compositions can be produced in both plume and island arc settings. The fact that Ti behaves differently during magma differentiation in these two geological settings might result in contrasting isotopic signatures. Here, we demonstrate that, at a given SiO 2 content, evolved plume rocks (tholeiitic) are more isotopically fractionated in Ti than differentiated island arc rocks (mainly calc-alkaline). We also show that the erosion of crustal rocks from whether plumes (mafic in average) or island arcs (intermediate in average) can all produce sediments having quite constant 49 Ti/ 47 Ti ratios being 0.1-0.3 per mille heavier than that of the mantle. This suggests that Ti isotopes are not a direct tracer for the SiO 2 contents of crustal rocks. Ti isotopes in crustal sediments are still a potential proxy to identify the geodynamical settings for the formation of the crust but only if combined with additional SiO 2 information. titanium isotopes | plume | island arc | magma differentiation | plate tectonic
Faire progresser l'élève de 2nde en français : quels outils efficaces ?
No full textQuels sont les outils les plus efficaces pour permettre des progrès en français pour l'élève de seconde ? Je me suis attachée à trouver quels seraient ceux qu'il faudrait retenir. Pour une réelle efficacité, il faut travailler à plusieurs niveaux et en simultané : sur le climat de classe, sur les travaux de groupe et sur l'élève en lui-même, par des grilles d'aides et d'(auto)évaluation. Tous ces outils sont liés
On the Link Between External Forcings and Slope Instabilities in the Piton de la Fournaise Summit Crater, Reunion Island
No full textInternational audienceWe have analyzed the impact of different forcings, such as rain and seismicity, on slope instabilites on an active volcano. For this, we compiled a catalog of the locations and volumes of rockfalls in the Piton de la Fournaise crater using seismic records. We validated it by comparing the locations and volumes to those deduced from photogrammetric data. We analyzed 10,477 rockfalls, spanning the period 2014 to 2016. This period corresponds to the renewal of volcanic activity after a 41‐month rest. Our analysis reveals that renewed eruptive activity has unsettled the crater edges. External forcings such as rain and seismicity are shown to potentially increase the number and the volume of rockfalls, with a stronger impact on the volume. Preeruptive seismicity seems to be the main triggering factor for the largest volumes, with a delay of one to several days. Rain alone does not seem to trigger especially large rockfalls. We infer that repetitive vibrations from the many seismic events, combined with the action of rain, induce crack (or slip) growth in highly fractured (or granular) materials, leading to the collapse of large volumes. Regarding their spatial distribution before an eruption, the largest rockfalls seem to migrate toward the location of magma extrusion
Checking Array Bounds by Abstract Interpretation and Symbolic Expressions
No full textInternational audienceArray access out of bounds is a typical programming error. From the '70s, static analysis has been used to identify where such errors actually occur at runtime, through abstract interpretation into linear constraints. However, feasibility and scalability to modern object-oriented code has not been established yet. This article builds on previous work on linear constraints and shows that the result does not scale, when polyhedra implement the linear constraints, while the more abstract zones scale to the analysis of medium-size applications. Moreover, this article formalises the inclusion of symbolic expressions in the constraints and shows that this improves its precision. Expressions are automatically selected on-demand. The resulting analysis applies to code with dynamic memory allocation and arrays held in expressions. It is sound, also in the presence of arbitrary side-effects. It is fully defined in the abstract interpretation framework and does not use any code instrumen-tation. Its proof of correctness, its implementation inside the commercial Julia analyzer and experiments on third-party code complete the work
Extensive CO 2 degassing in the upper mantle beneath oceanic basaltic volcanoes: First insights from Piton de la Fournaise volcano (La Réunion Island)
No full textInternational audienceIn spite of its major role on the atmospheric volatile budget, climate, and tracking magmatic transfers, mantle (CO2) degassing below volcanoes is still poorly understood. Most of the studies on this scientific topic lack constraint on the CO2 concentration of primary melts, the depth at which it starts degassing, and the extent of this process in the mantle. In this study of Piton de la Fournaise (PdF) volcano, we couple geochemistry of low solubility gases (He, Ar, CO2, δ13C) in fluid inclusions (FIs) and petro-chemistry of magmatic inclusions on a set of olivine and clinopyroxene crystals from basalts and ultramafic enclaves.We constrain basaltic melt degassing at PdF over a large pressure range (from 4 GPa up to the surface). Based on CO2-He-Ar systematics, we infer that extensive degassing occurs already in the upper mantle (4–1 GPa) and it is favored by multiple steps of magma ponding and differentiation up to the mantle-crust underplating depth (0.4 GPa). Thus, we calculate that basaltic melts injected at crustal depth (<0.4 GPa) have already exsolved ∼94 ± 5 wt% of their primary CO2 content in accordance with (1) the evolved and degassed signature of erupted lavas and (2) the weakness of inter-eruptive gas emissions in the active area bearing low-temperature vapor-dominated fumaroles. Our results at PdF strongly contrast with previous findings on other ocean island volcanoes having a higher magma production rate and faster magma ascent, like Kilauea (Hawaii), whose basalts experience only limited extent of differentiation and degassing. We propose that extensive degassing already in the upper mantle can be a common process for many volcanoes of the Earth and is tightly dependent on the dynamics of magma ascent and differentiation across multiple ponding zones.Based on the modeling developed in this study, we propose a new estimation of the CO2 content (up to 3.5 ± 1.4 wt%) in primary basaltic melts at PdF leading to a carbon content in the mantle source of 716 ± 525 ppm. This new estimation is considerably higher than the few previous calculations performed for Ocean Island Basalts (OIB) systems. Another implication of this work involves the possible bias between the δ13C measured in volcanic gas emissions (<−6‰) and that of primary vapour phase (−0.5 ± 0.5‰) constrained in this work. This bias would confirm the early step of extensive CO2 degassing within the upper mantle and could represent an alternative for the hypotheses of carbon recycling or mantle heterogeneity in support of the low δ13C signature of some mantle reservoirs. This study bears significant implications on the global budget of volcanic volatile emissions, chiefly regarding the contribution of past and future emissions of volcanic CO2 to climate dynamics, and on volcanic gas monitoring
Dietary diversity of 6- to 59-month-old children in rural areas of Moramanga and Morondava districts, Madagascar
No full textInternational audienceBACKGROUND:A dietary imbalance or a disregard for the nutritional needs of children during early childhood can affect their growth. From the age of six months, breast milk is no longer able to meet the energy and micronutrient needs of children; the consumption of adequate complementary foods is therefore essential. Various indicators have been used to assess the quality of children's diets, and the dietary diversity score is a good indicator of children's diets. The objective of this study was to describe the dietary practices of children in rural areas of Moramanga and Morondava, Madagascar, and to identify the determinants of low dietary diversity to prioritize nutritional interventions.METHODS:We collected dietary data in 2014 on children aged 6-59 months in a study on the determinants of chronic malnutrition using the 24-hour recall method. Data on the characteristics of households and mothers were also collected. We carried out bivariate and multivariate analyses to identify the determinants of low dietary diversity scores for children.RESULTS:We included 1824 children: 893 from Moramanga and 931 from Morondava. Approximately 42.1% [95% CI: 39.0-45.4] of the children from Moramanga and 47.6% [95% CI: 44.4-50.8] of those from Morondava had a poorly diversified diet, consisting mainly of foods rich in carbohydrates and poor in meat products. Poor maternal education was associated with a high likelihood of having a non-varied diet in both study areas; the adjusted odds ratios were 2.2 [95% CI: 1.3-3.8] and 4.0 [95% CI: 2.5-6.4] for children from mothers with lower education levels for Moramanga and Morondava, respectively. For children recruited in Morondava, having low household socioeconomic status (adjusted OR: 1.8, 95% CI: 1.2-2.8) and belonging to a household without livestock was associated with a low dietary diversity score (adjusted OR: 1.8, 95% CI 1.2-2.7).CONCLUSION:Our results show the need to improve girls' education, adapt nutrition education programs for mothers based on their level of education, and strengthen poverty reduction programs
Diversity of condensed tannins in Vitaceae
No full textDiversity of condensed tannins in Vitaceae. 12. International Conference on Grapevine Genetics and Breedin
