Portail "HAL-Francophonie Afrique et Océan Indien"
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Réseaux d'endossements et risque systémique : une approche markovienne et multi-agents appliquée aux effets de commerce
No full textCet article propose une modélisation novatrice de la responsabilité solidaire dans la chaîne d'endossements des effets de commerce, en mobilisant les chaînes de Markov, la programmation dynamique et l'intelligence artificielle. Contrairement aux pratiques comptables actuelles, fondées sur une provision forfaitaire centralisée, notre approche introduit une ventilation dynamique du risque entre les différents endosseurs. Les résultats théoriques et graphiques montrent que l'intégration d'une fonction de coût (pénalité de retard) et l'optimisation intertemporelle permettent de mieux capter la diffusion du risque et de traduire la solidarité juridique en responsabilité financière. Cette contribution s'inscrit dans une perspective d'innovation comptable, en repensant la comptabilisation du risque de crédit dans un cadre dynamique et probabiliste.</div
Mesoscale dynamics and transport in the North Brazil Current as revealed by the EUREC4A-OA experiment
No full textInternational audienceThe North Brazil Current (NBC) rings are key features for interhemispheric water transport, facilitating exchange between the South Atlantic and North Atlantic Ocean. However, significant uncertainties persist regarding the total volume transported by these structures and the water masses they advect. In this study, we integrate high-resolution in situ observations from the EUREC4A-OA field experiment with satellite altimetry to address these knowledge gaps. Using a novel methodology, we estimate that surface NBC rings transport approximately 1.5 Sv, while subsurface eddies contribute between 0.4 and 9.7 Sv, underscoring their critical role in the regional total transport. Combined, these transports may significantly contribute to closing the Atlantic Meridional Overturning Circulation transport at low latitudes. Surface NBC rings predominantly advect Salinity Maximum Waters and fresh waters from the Amazon River, whereas subsurface NBC rings play a critical role in transporting Eastern South Atlantic Central Waters, Western South Atlantic Central Waters, and Antarctic Intermediate Waters northward. We estimate that the heat transport by surface and subsurface NBC rings is 5.8 and 0.3 TW, respectively, which is significantly lower than previous findings. Overall, these findings underscore the pivotal role of subsurface NBC rings as conduits for South Atlantic Waters across the Equator to the tropical North Atlantic. This study confirms the intricate dynamics of NBC rings and their essential role in interhemispheric water transport
Variability of environmental, contextual and individual factors in human-shark interactions in New Caledonia, 1980–2022, with some comparisons to Reunion Island
No full textInternational audienceThis paper analyses data related to 62 human–shark interactions in New Caledonia and 60 in Reunion Island from 1980 to 2022. A database on human–shark interactions in New Caledonia and Reunion Island was developed using the same variables and similar time steps for both locations. The discussion focuses on human–shark interactions in New Caledonia, with some comparisons to those on Reunion Island where possible. Environmental, contextual and individual variables related to human–shark interactions were analysed to identify potential influencing factors. The data analysis for New Caledonia revealed some correlations between variables related to the human–shark interactions. The main results showed that there was a concomitant increase in human–shark interactions since 2010 in the bays of Noumea and in the prevalence of human–shark interactions among people practising boardsports since 2007. The year 2007 was a pivotal year with respect to differences in important parameters of human–shark interactions. The results of this comparison between Reunion Island and New Caledonia were as follows: fatal human–shark interactions occurred among individuals practising boardsports and in turbid environments, whereas nonfatal human–shark interactions among individuals engaged in spearfishing and in clear water in New Caledonia
Technologies numériques et microfinance pour le développement touristique local : vers un modèle intégré de financement durable
No full textCet article explore l'intégration des technologies numériques dans la microfinance appliquée au développement touristique local. À travers un modèle intégré combinant finance, tourisme et informatique, nous démontrons que le numérique agit comme un levier stratégique, optimisant la gestion des microcrédits, améliorant la transparence et renforçant la viabilité économique et sociale des projets touristiques communautaires. Les résultats mettent en évidence un cercle vertueux où l'accès au financement stimule l'activité touristique, génère des revenus réinjectés dans le système et renforce la confiance entre acteurs. L'étude propose également des pistes pour la mise en œuvre opérationnelle et des perspectives pour la recherche future
Regard sur des pratiques orales en classe à La Réunion : un enjeu professionnel pour réduire les inégalités ?
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Trophodynamics in Coral Reefs: Current Knowledge and Research Perspectives
No full textInternational audienceCoral reef trophodynamics is extremely complex and still poorly understood, while investigated for decades. Recent advances on organic matter sources, fluxes, trophic niches of species, and spatiotemporal variations of food webs are first summarized. Then, tools used in trophodynamics research are briefly documented, from traditional pioneer methods of stomach content analysis to more recent biochemical methods (stable isotopes, fatty acids, biochemical composition, metabolomics, DNA metabarcoding, etc.) and modeling approaches. Eventually, future challenges and perspectives are presented addressing the diverse scenarios of coral reef trophic functioning response in front of the ongoing changes in global and local stressors
A comprehensive framework for the delimitation of species within the Bemisia tabaci cryptic complex, a global pest-species group
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/609041/)International audienceIdentifying cryptic species poses a substantial challenge to both biologists and naturalists due to morphological similarities. Bemisia tabaci is a cryptic species complex containing more than 44 putative species; several of which are currently among the world's most destructive crop pests. Interpreting and delimiting the evolution of this species complex has proved problematic. To develop a comprehensive framework for species delimitation and identification, we evaluated the performance of distinct data sources both individually and in combination among numerous samples of the B. tabaci species complex acquired worldwide. Distinct datasets include full mitogenomes, single-copy nuclear genes, restriction site-associated DNA sequencing, geographic range, host speciation, and reproductive compatibility datasets. Phylogenetically, our well-supported topologies generated from three dense molecular markers highlighted the evolutionary divergence of species of the B. tabaci complex and suggested that the nuclear markers serve as a more accurate representation of B. tabaci species diversity. Reproductive compatibility datasets facilitated the identification of at least 17 different cryptic species within our samples. Native geographic range information provides a complementary assessment of species recognition, while the host range datasets provide low rate of delimiting resolution. We further summarized different data performances in species classification when compared with reproductive compatibility, indicating that combination of mtCOI divergence, nuclear markers, geographic range provide a complementary assessment of species recognition. Finally, we represent a model for understanding and untangling the cryptic species complexes based on the evidence from this study and previously published articles
Quantitative assessment of groundwater discharge using hydrograph separation and spring discharge in the Ouémé valley, southern Benin
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Razionalità ermeneutica e euristicità della filosofia africana: Contributo di Jean Kinyongo Jeki
No full textInternational audienceDieser Artikel untersucht, wie Jean Kinyongo Jeki zur Entwicklung einer spezifischen Heuristik der afrikanischen Philosophie durch das Prisma der hermeneutischen Rationalität beiträgt. Angesichts der Herausforderung, einen strengen und methodisch fundierten afrikanischen philosophischen Diskurs zu formulieren, vollzieht Kinyongo einen hermeneutischen Umweg, der zu einer epistemologischen Notwendigkeit wird. Dieser Umweg führt ihn dazu, „Elemente der philosophischen Diskursivität“ zu identifizieren — wesentliche Bestandteile der intelligiblen Form des afrikanischen philosophischen Diskurses — und zu postulieren, dass deren Artikulation ein hermeneutisches Paradigma erfordert. Die hermeneutische Rationalität wird somit zum Hebel einer authentischen philosophischen Verwirklichung Afrikas, gegründet auf einer „Philosophie der philosophischen Elemente“, die durch einen „diskursiven Weg“ umgesetzt wird. Durch diese Übersetzungsarbeit des Konzepts der Diskursivität, verbunden mit einer hermeneutischen Epistemologie, gelingt es Kinyongo, der afrikanischen Philosophie eine heuristische Ausdruckskraft zu verleihen, die mit ihren inneren Dynamiken der Bedeutung verbunden ist.This article explores how Jean Kinyongo Jeki contributes to the development of an intrinsic heuristic dimension within African philosophy, viewed through the lens of hermeneutic rationality. Faced with the challenge of articulating a rigorous and methodologically grounded African philosophical discourse, Kinyongo undertakes a hermeneutic detour that ultimately becomes an epistemological necessity. This turn leads him to identify "elements of philosophical discursivity"—core components of the intelligible form of African philosophical discourse—and to assert that their articulation requires a hermeneutic paradigm. Hermeneutic rationality thus emerges as a driving force for the authentic realization of African philosophy, anchored in a "philosophy of philosophical elements" pursued through a "discursive pathway." Through his effort to philosophically translate the concept of discursivity, framed within a hermeneutic epistemology, Kinyongo succeeds in rendering African philosophical thought heuristic—expressive of its internal dynamics of meaning.Este artículo explora la manera en que Jean Kinyongo Jeki participa en la elaboración de una heuricidad propia de la filosofía africana a través del prisma de la racionalidad hermenéutica. Ante el desafío de formular un discurso filosófico africano riguroso y metodológicamente fundado, Kinyongo realiza un rodeo hermenéutico que se convierte en una necesidad epistemológica. Este rodeo lo conduce a identificar «elementos de discursividad filosófica» — componentes esenciales de la forma inteligible del discurso filosófico africano — y a postular que su articulación exige un paradigma hermenéutico. La racionalidad hermenéutica se convierte así en el eje de una auténtica realización filosófica africana, fundada en una «filosofía de los elementos filosóficos» puesta en práctica mediante un «camino discursivo». Con este esfuerzo de traducción del concepto de discursividad, apoyándolo en una epistemología hermenéutica, Kinyongo logra otorgar una expresividad heurística al pensamiento africano en filosofía, articulado con sus dinámicas internas de significación.Cet article explore la manière dont Jean Kinyongo Jeki participe à l’élaboration d’une heuristicité propre à la philosophie africaine à travers le prisme de la rationalité herméneutique. Face au défi de formuler un discours philosophique africain rigoureux et méthodologiquement fondé, Kinyongo opère un détour herméneutique qui devient une nécessité épistémologique. Ce détour l’amène à identifier des « éléments de discursivité philosophique » — composantes essentielles de la forme intelligible du discours philosophique africain — et à postuler que leur articulation exige un paradigme herméneutique. La rationalité herméneutique devient ainsi le levier d’une authentique réalisation philosophique africaine, fondée sur une « philosophie des éléments philosophiques » mise en œuvre par un « cheminement discursif ». Par cet effort de traduction du concept de discursivité, en l’adossant à une épistémologie herméneutique, Kinyongo parvient à donner une expressivité heuristique à la pensée africaine en philosophie, articulée à ses dynamiques internes de signification.Questo articolo esplora il modo in cui Jean Kinyongo Jeki partecipa all’elaborazione di un’euristicità propria della filosofia africana attraverso il prisma della razionalità ermeneutica. Di fronte alla sfida di formulare un discorso filosofico africano rigoroso e metodologicamente fondato, Kinyongo compie un détour ermeneutico che diventa una necessità epistemologica. Questo détour lo porta a identificare «elementi di discorsività filosofica» — componenti essenziali della forma intelligibile del discorso filosofico africano — e a postulare che la loro articolazione esiga un paradigma ermeneutico. La razionalità ermeneutica diventa così la leva di una autentica realizzazione filosofica africana, fondata su una «filosofia degli elementi filosofici» attuata mediante un «cammino discorsivo». Con questo sforzo di traduzione del concetto di discorsività, ancorandolo a un’epistemologia ermeneutica, Kinyongo riesce a conferire un’espressività euristica al pensiero africano in filosofia, articolato alle sue dinamiche interne di significazione
Review of the Mechanisms, Pros and Cons of Some Drying Technologies Applicable to Agricultural Food Products' Processing
No full textInternational audienceDrying of agricultural food products is an essential unit operation that aims at preventing the alteration of the product's microstructure due to moisture and microbial activities, which invariably deters the shelf life of agricultural food products. This review presents the drying mechanisms of agricultural food products with a critical assessment of drying applications, from first‐generation sun drying and shade drying methodologies to contemporary approaches like freeze‐drying, infrared drying, microwave drying, spray drying, foam‐mat drying, electrohydrodynamic drying, and a combination of some drying technologies like hot air with infrared, vacuum, ultrasound‐assisted vacuum, and microwave drying methods. This review also identified the advantages, limitations, and future prospects of each drying application, with a keen interest in the drying time and quality of the agricultural food end products. This review presents guiding information that could aid in selecting a suitable drying method that will not only be relatively economical but will also yield end products with desirable qualities