International Journal of Agricultural Research, Innovation and Technology (IJARIT)
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Présentation du projet « recyclage des déchets du BTP et développement de nouveaux matériaux en milieu insulaire »
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Modélisation de la propagation de rumeur: Impact de la distribution des distances dans un réseau
No full textsoumission à EpisciencesThe number of social networks is growing rapidly in the digital world. While they offer many opportunities, they also pose risks in terms of misinformation and negative influence on individual behavior. Although several studies of rumor propagation exist in the literature, we have not identified any that explicitly study the impact of the distribution of inter-summit distances. We propose an IS2R compartmental model for which the propagation strength incorporates the distance distribution and the proportion of ignorant. The activity of the stiflers is also taken into account. A qualitative analysis of the model reveals several invariants and multi-stability. An analysis of the sensitivity to the degree distribution shows that, depending on the configuration of the network, the factors influencing the propagation force are of varying levels. The degree distribution according to the power law seems to limit the rumor propagation for a relatively high form factor.Le nombre de réseaux sociaux est en pleine croissance dans l'univers du numérique. En même temps qu'ils offrent de nombreuses opportunités, ils représentent également des risques en matière de désinformation et d'influence négative des comportements individuels. Bien que plusieurs études de propagation de rumeurs existent dans la littérature, nous n'en avons pas identifié qui étudie explicitement l'impact de la distribution des distances inter-sommets. Nous proposons un modèle compartimental IS2R pour lequel la force de propagation intègre la distribution des distances et la proportion des ignorants. L'activité des étouffeurs est également prise en compte. Une analyse qualitative du modèle révèle plusieurs invariants et une multi-stabilité. Une analyse de la sensibilité à la distribution des degrés montre que selon la configuration du réseau les facteurs influençant la force de propagation sont de niveaux variables. La distribution de degrés selon la loi des puissances semble limiter la propagation de rumeur pour un facteur de forme relativement élevé
Seismic sources of InSight marsquakes and seismotectonic context of Elysium Planitia, Mars
No full textInternational audienceSince early 2019, the InSight mission has proven that Mars is seismically active, with more than 900 seismic events recorded. Among them, several events have characteristics close to terrestrial tectonic earthquakes. Most of these events are located on the major graben system of Cerberus fossae and, a little further north, on the secondary system of Grjotá Valles. In this study, we invert the seismic moment tensors for nine of these tectonic marsquakes characterized by high quality data. Seven of them are located on Cerberus fossae/Grjotá Valles and two of them are located near the Martian dichotomy. The moment tensors allow us to interpret the nature and depth of the seismic sources at the origin of these events. In our approach, we invert the P and S body waveforms, the PP, SS, PPP and SSS secondary phase maximum amplitudes and we look for solutions with surface waves weaker than the Martian noise. From our results on moment tensors, we determine that all our events have been triggered at moderate depths of 15-36 km. We deduce that the seven events located on Cerberus fossae have geometries similar to the fractures and are generated by tectonics. This activity is supposed to result from the reactivation of previous faults and fractures, which would have been initially induced by the propagation of volcanic dikes at depth. The two dichotomy events are due to deep compressive fracturing of the Martian lowlands. They are therefore triggered by the planetary thermal contraction. Our results are in strong agreement with recent studies on the event depths and on the previous moment tensors calculated for two events
Current status of PTMs structural databases: applications, limitations and prospects
No full textInternational audienceProtein 3D structures, determined by their amino acid sequences, are the support of major crucial biological functions. Post-translational modifications (PTMs) play an essential role in regulating these functions by altering the physicochemical properties of proteins. By virtue of their importance, several PTM databases have been developed and released in decades, but very few of these databases incorporate real 3D structural data. Since PTMs influence the function of the protein and their aberrant states are frequently implicated in human diseases, providing structural insights to understand the influence and dynamics of PTMs is crucial for unraveling the underlying processes. This review is dedicated to the current status of databases providing 3D structural data on PTM sites in proteins. Some of these databases are general, covering multiple types of PTMs in different organisms, while others are specific to one particular type of PTM, class of proteins or organism. The importance of these databases is illustrated with two major types of in silico applications: predicting PTM sites in proteins using machine learning approaches and investigating protein structure–function relationships involving PTMs. Finally, these databases suffer from multiple problems and care must be taken when analyzing the PTMs data
L’engagement des pays dans l’intégration régionale CEMAC
No full textInternational audienceLa capacité à porter et à mettre en œuvre les textes, traités et projets communautaires, pourtant ratifiés, est devenue, depuis quelques années, une préoccupation majeure dans la communauté économique et monétaire de l’Afrique centrale (CEMAC). À titre d’illustration, l’Acte Additionnel n°02/01-CEMAC-066-CE-03 portant création d'une Compagnie Communautaire de Transports Aériens en zone CEMAC, pris en 2001 n’a jamais été appliqué. Il en est de même du Règlement N°9/00/CEMAC-067-CM-04 portant adoption du réseau routier intégrateur et prioritaire de la CEMAC. [...
O PICARESCO EM VOLTAIRE: UMA LEITURA DE CANDIDE OU L'OPTIMISME
No full textdes Geosciences Resumo O romance picaresco é um gênero da literatura clássica espanhola, também identificado sob nome de literatura picaresca, ou novela picaresca, e apresenta um anti-herói burlão, mendigo, aventureiro, parasitas e fora do comum. Neste trabalho abordamos as características picarescas em Candide ou l'Optimisme, de Voltaire. Trata-se do acompanhamento da vida do Candide: suas origens, sua errância, seu comportamento e outras características, em comparação com o precursor do romance picaresco, Lazarillo de Tormes (1554), de Anónimo do século XVI, recorrendo, em alguns casos a Guzmán de Alfarache (1599) de Mateo Alemân e El Buscón (1626.), de Francisco de Quevedo
« Refoulé et recentré » : dynamiques touristiques et patrimoniales en Afrique du Sud et au Mozambique: Tomes 1 & 2 : Parcours et Productions
No full textMonsieur TAGLIONI François, Pr en géographie, Université́ de La Réunion, Madame FOURNET-GUÉRIN Catherine, Pr en géographie, Sorbonne Université - Madame GRAVARI-BARBAS Maria, Pr en géographie, Université Paris 1 Panthéon-Sorbonne, rapporteure - Monsieur JAUZE Jean-Michel, Pr en géographie, Université́ de La Réunion, garant de l'HDR - Monsieur LAJOIE Gilles, Pr en géographie, Université́ de La Réunion, rapporteur - Madame MAINET Hélène, Pr en géographie, Université́ de Clermont Auvergne, rapporteureAbstractThis H.D.R. dissertation is organised around a geographical thought anchored on the notions of refoulement and recentering/recoding.The area of study is located in Southern Africa (South Africa and Mozambique), delimited by six major urban spaces: Johannesburg and Pretoria in the South African highlands; Durban and Pietermaritzburg in the coastal province of KwaZulu-Natal; Maputo and Matola located in the southern part of Mozambique.The phenomenon of 'Dynamics of Heritage Margins' lies at the heart of the analytical and systemic work carried out here, which is based on over a decade of research.The analysis focuses on the recompositions and (re)valorisation of geographical places and historical facts, through both tourism and cultural heritage enhancement.It targets the place and evolution of "margins" subjects, which can be considered as peripheral and/or repressed objects/places with a very strong memory-based potential. Their past remains attached to a dark or painful history; it is re-exalted in various forms.In the end, the tourist heritage of those "sensitive" materials brings together issues and temporalities. It opens up to a varied public and allow to appreciate strategies of actors with a specific agenda. It ends up expressing phenomena of territorialization and memorialization.RésuméCe mémoire d’H.D.R. s’organise autour d’une pensée géographique ancrée sur les notions de refoulement et de recentrage/recodage.Le terrain concerné se situe en Afrique australe (Afrique du Sud et Mozambique), délimité par six espaces urbains prioritaires : Johannesburg et Pretoria sur les hautes terres sud-africaines ; Durban et Pietermaritzburg dans la province littorale du KwaZulu-Natal ; Maputo et Matola sis dans la partie méridionale mozambicaine.Le phénomène de « Dynamiques des marges patrimoniales » se situe au cœur du travail analytique et systémique mené, lequel repose sur plus d’une décennie de recherche.La réflexion porte sur les recompositions et la (re)valorisation de lieux géographiques et de faits historiques, par une mise en valeur à la fois touristique et patrimoniale.Elle cible la place et l’évolution de sujets tenant des « marge ». Ces dernières peuvent se considérer comme des objets-lieux périphériques et/ou refoulés au très fort potentiel mémoriel (soit aussi l’idée d’une ressource de territoire). Leur passé demeure effectivement attaché à une histoire pesante ou douloureuse ; il se voit ré-exalté sous diverses formes.Au final, la patrimonialisation touristique des matériaux « sensibles » met en interrelation enjeux et temporalités. Elle s’ouvre à un public très varié et permet d’apprécier différentes stratégies d’acteurs détenant un agenda précis. Elle finit aussi par exprimer des phénomènes de territorialisation et de mémorialisation
Intégration par une approche implicite d’une loi de comportement elastoplastique dans le code de calcul par éléments finis Cast3M
No full textsoumission à EpisciencesInternational audienceThis paper is dedicated to the implementation of a law of mechanical behavior in the finite element software Cast3M using an open source code generator named Mfront. To do so, an elastoplastic behaviour model has been chosen from existing laws in the literature. Following an implicit discretization, a hardware library corresponding to the isotropic and kinematic strain-hardening model is generated using Mfront. The UMAT computer interface is used to build the library in Cast3M. A validation of the approach has been carried out by comparing the numerical results obtained with the generated hardware library and the equivalent pre-existing library in Cast3M. Simulations in the case of a tensile bar and a perforated plate show almost identical resultsCe papier est dédié à l’implantation d’une loi de comportement mécanique dans le logiciel éléments finis Cast3M à l’aide d’un générateur de code open source nommé Mfront. Pour ce faire, un modèle de comportement élasto-plastique a été choisi à partir des lois existantes dans la littérature. Suivant une discrétisation implicite, une bibliothèque matérielle correspondant au modèle de CHABOCHE à écrouissage isotrope et cinématique non linéaire est générée grâce à Mfront. L’interface informatique UMAT est utilisée pour construire la bibliothèque dans Cast3M. Une validation de l’approche a été menée en comparant les résultats numériques obtenus entre la bibliothèque matérielle générée et la bibliothèque équivalente préexistante dans Cast3M. Les simulations dans le cas d’une barre en traction et une plaque trouée montrent des résultats quasi identique
Variability of Sea-Surface Magnetic Anomalies at Ultraslow Spreading Centers: Consequence of Detachment Faulting and Contrasted Magmatism?
No full textInternational audienceThe capacity of oceanic crust to record geomagnetic polarity reversals makes sea-surface magnetic anomalies an essential tool to study plate tectonics. The anomalies are usually well-defined at magmatic spreading centers, but are distorted and eventually disappear on magma-poor mid-ocean ridges such as the ultraslow Southwest Indian Ridge (SWIR), making their interpretation difficult. We attribute the variability of the SWIR sea-surface magnetic anomalies to the alternance of magmatic spreading and detachment faulting. A three-layer magnetic model is used to simulate the influence of such an alternance on the sea-surface magnetic anomalies. Conversely, observed magnetic profiles at the SWIR are modeled to unravel their off-axis crustal structure and past mode of spreading. The intruding gabbro bodies on the footwall of detachment faults play a major role in explaining the variability of sea-surface magnetic anomalies at slow and ultraslow spreading ridges
Coexistence of Adjacent Siliciclastic, Carbonate, and Mixed Sedimentary Systems: An Example From Seafloor Morphology in the Northern Lesser Antilles Forearc
No full textInternational audienceThree main types of factors commonly control the nature of the clasts, the arrangement of the distinctive lithologies, and the general architecture of turbidite systems: sedimentation rate and carbonate production; climates and glacio-eustatism; and morphology and tectonics. The coexistence of adjacent systems of distinctive nature is, however, scarcely documented, and the relative influence of each factor needs better constrain. In the Northern Lesser Antilles Segment (NLAS), carbonate and siliciclastic sediment sources coexist within a 150 km lateral distance, with carbonate platforms lying onto a volcanic substratum, and by a succession of spurs and triangular valleys that are bounded by active normal faulting. To better understand the factors controlling sedimentary processes from the carbonate platform sources to the deep-sea sinks, we used backscatter, bathymetry, multichannel seismic, and sub-bottom profiles. Sedimentary systems are dominated by siliciclastic input (by retrogressive erosion of confined canyons affecting the volcanic slope), carbonate input (by carbonate sediment transported by oceanic- and wind-driven submarine currents beyond the leeward edges of carbonates platforms), or both. In the mixed systems, the retrogressive erosion of the canyon head determines the nature of the source (volcanic on the slope, carbonate when the canyons reach the shelf edge). Glacio-eustatism has a key role in carbonate availability on the platform, as attested by the presence of drowned platforms. The main contribution of this study is the identification of the major role that tectonic activity plays in the short-distance coexistence of the distinctive sedimentary systems since fault-bounded V-shaped valleys in map view offer alternating leeward and windward edges favoring carbonate or mixed systems. Additionally, the steep slope gradient induced by normal faults and regionalsubsidence seems to be the main factor controlling sediment dispersal. It causes multiple line sources and the dispersion of gravity-driven currents under the effect of hydraulic jumps, thus preventing the formation of a channelized system. Our study provides a modern analog of adjacent systems dominated by distinctive lithologies in a tectonically active area. The results appear particularly appropriate to decipher the nature of ancient source-to-sink systems dominated by complex tectonics, paleo-bathymetry, and sediment routings