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Comparative seed physiological ecology in Coffea species highlights variation in germination strategies associated with climate and phylogeny
No full textSource Agritrop Cirad (https://agritrop.cirad.fr/617001/)International audienceBackground and Aims Seed functional traits are poorly understood in species of tropical origin with endospermic or desiccation-sensitive seeds. Species of the genus Coffea have colonized a broad range of forest habitats of Africa and Indian Ocean islands, from seasonally dry savannah woodlands to permanently humid evergreen forests. All Coffea species produce albuminous seeds, most of which are desiccation-sensitive, thereby offering a valuable model to identify adaptive seed traits in this understudied category of plants. Methods Several morphological traits (tissue masses and mass ratios, embryo depth inside the endosperm) and physiological traits (desiccation tolerance, germination and seedling establishment kinetics) were measured in 28 Coffea species, and associations with bioclimatic variables and phylogeny were investigated. Key Results The time required for seed germination was influenced by both the thickness of the micropylar endosperm and the relative mass of the endocarp to the seed. The time from germination to the unfolding of cotyledonary leaves was correlated with the endosperm mass. Finally, the time for seedling establishment, seed germination and drying sensitivity were positively associated with rain variables, suggesting that these physiological traits were driven by adaptation to seasonal water stress. Significant phylogenetic signal was detected for most seed traits with the exception of seed desiccation sensitivity, germination time and embryo depth inside the endosperm, which appeared to be evolutionarily labile, i.e. highly divergent between phylogenetically closely related species that occur in contrasted habitats. Conclusions The present study highlights the spectrum of coordinated seed traits shaped by phylogeny and/or ecological adaptation among Coffea species. This is illustrated by the co-option of several characteristics (small, thinly endocarp-coated, desiccation-tolerant and fast-germinating seeds) that enable fast seedling establishment and may confer an ecological advantage in the studied species of the East Africa clade that occur in seasonally dry habitats
Jëfandikoo model ngir seetlu tukki yi ñeel nappum Senegal bu artisanal bi
No full textThe North-West African coast is enriched by the Canary current, which sustain a very produc- tive marine ecosystem. The Senegalese artisanal fishing fleet, the largest in West Africa, ben- efit from this particularly productive ecosystem. It has survived the ages with remarkable adaptability, and has great flexibility allowing it to react quickly to changes, in particular by changing fishing gear and performing migrations. However, since the 1980s, the increasing fishing effort led to a progressive fish depletion, increasing fisher’s migration distances to access new fishing grounds. Since 2007 many fishers even started to navigate to Canary archi- pelago in order to find a more lucrative job in Europe, carrying candidate to emigration in their canoes. This phenomenon further increased since 2022 due to a new drop in fishery yields, consecutive to the development of fishmeal factories along the coast that amplified overfishing. Climate change may also impact fish habitat, and by consequence the distribution of fishing grounds. The question addressed in this research was how climate change, fishing effort and socio-economic parameters interact and determine the artisanal fishery dynamics. An interdisciplinary approach allowed us to collect data and qualitative information on cli- mate, fishing effort and socio-economic parameters. This served as a basis to build a multi- agent model of the mobility of Senegalese artisanal fishing. We implemented a first version of the model and presented some preliminary simulations with contrasted fishing effort and climate scenario. The results suggested that first, climate change should have only a slight impact on artisanal fishing, even in the most extreme climate scenario considered. Second, if fishing effort was maintained at current levels, we found a collapse of the fishery with massive fishers migrations whatever the climate scenario. Third, with reduced fishing effort, a sustain- able fishery equilibrium emerges in which Senegal's artisanal fishery catches ~250,000 tons of fish a year mostly in Senegal, approaching the 2000s catches records. This sustainable equi- librium maintained with the two-climate change scenario tested. Fishers migrations provide clues of the fish populations state and have implications for the sustainable exploitation of fishing resources. Senegalese artisanal fishers’ migrations impact the regional distribution of the fishing effort, therefore must be taken into account in regional development and planning policies for this sector, particularly in a context of increasing infrastructure and spatial man- agement measures (e.g. marine protected areas). This work lays the foundations of a computer simulation tool for decision support.La flotte de pêche artisanale sénégalaise, composée de près de 20 000 pirogues, est la plus importante d’Afrique de l’Ouest. Elle a traversé les époques avec une remarquable adaptabilité, et possède une grande souplesse lui permettant de réagir rapidement aux changements, notamment par le changement des engins de pêche et par la mobilité à l’échelle sous régionale. Les dynamiques d’auto-organisation de ce secteur ont fait l’objet de nombreuses études qui visent à soutenir la cogestion. La mobilité de l’effort de pêche a des implications sur l’exploitation durable des ressources halieutique, et est donc un aspect à prendre en compte dans les politiques de développement et d’aménagement de ce secteur, notamment dans un contexte de multiplication des infrastructures et des mesures de gestions spatiales (e.g. aires marines protégées). Ici nous proposons une description détaillée d’un modèle multi-agent de la mobilité de la pêche artisanale sénégalaise. Nous tentons de positionner le modèle à un niveau de complexité intermédiaire, en synthétisant les éléments présents dans la littérature pour décrire une image simplifiée de la flotte de pêche artisanale. Ce travail jette ainsi les bases d’un outil informatique de simulation pour l’aide à la décision. Nous avons mis en œuvre une première version du modèle et présenté quelques simulations préliminaires avec des scénarios contrastés en matière d'effort de pêche et de climat. Les résultats suggèrent un impact modéré du changement climatique ne devrait avoir qu'un impact limité sur la pêche artisanale, du fait de la forte mobilité de celle-ci. Deuxièmement, si l'effort de pêche était maintenu à son niveau actuel, le modèle suggère un effondrement de la pêche accompagné d'une migration massive des pêcheurs, quel que soit le scénario climatique. Troisièmement, avec un effort de pêche réduit, un équilibre durable de la pêche émerge du model, dans lequel la pêche artisanale sénégalaise capture environ 250 000 tonnes de poissons par an, principalement au Sénégal, ce qui se rapproche des niveaux de captures des années 2000. Cet équilibre durable se maintient avec les deux scénarios de changement climatique testés. Les migrations des pêcheurs fournissent des indices sur l'état des populations de poissons et impactent la répartition régionale de l'effort de pêche. Ces migrations devraient donc être prises en compte dans les politiques régionales de développement et de planification de ce secteur, en particulier dans un contexte de renforcement des infrastructures et des mesures de gestion spatiale (par exemple, les aires marines protégées). Ce travail jette les bases d'un outil de simulation informatique pour l'aide à la décision
Droits de douane d'urgence: l'heure du remboursement
No full texthttps://www.leclubdesjuristes.com/international/droits-de-douane-de-trump-lheure-du-remboursement-14846
Application of Raman thermometry to charcoals from archaeological sites: assessing the effect of wood chemistry and post-depositional effects on apparent carbonization temperature
No full textInternational audienceCharcoal is a key archaeological artefact, providing evidence of human presence, enabling site dating and delivering information about ancient practices notably through Raman thermometry. This study explores how it can be used to investigate past anthropogenic practices, considering carbonization temperature, wood chemistry, and post-depositional processes. Two complementary approaches were applied. Firstly, the experimental approach quantified the impact of initial wood chemistry on Raman parameters. 41 wood species were chemically characterized by FTIR and carbonized at 400, 600, and 800 • C. Raman spectra of charcoal showed that the D/G band height ratio (HD/HG) is influenced by wood chemistry, although this effect decreases at higher temperatures. In contrast, the area ratio (AD/AG) was less sensitive. Parameters associated with aliphatic compounds (α 1200-1265) and hydrocarbons trapped within aromatic structures (α 1415-1445 ), also varied with wood chemistry. Secondly, archaeological charcoals from Matadi and Ndouni (Gabon) were analysed to see if Raman spectra could reveal past uses. Results showed that post-depositional alterations affect HD/HG and AD/AG ratios, but, despite this, archaeological information was retrieved. At Matadi, radiocarbon dating distinguishes two fire episodes, while Raman analysis indicates higher fire intensity during the Early Iron Age, consistent with magnetic susceptibility measurements. At Ndouni, pottery-embedded charcoals displayed stronger aliphatic and hydrocarbon signals than those from soils, likely due to contact with fats from culinary use. Raman spectroscopy can be a complementary tool for enriching archaeological interpretations such as fire intensities or potential uses, despite the combination of multiple factors
Du bateau à l’avion : dynamiques d’ouverture et limites du désenclavement à Sainte-Hélène
No full textInternational audienceCe document a été généré automatiquement le 12 mars 2026.Le texte seul est utilisable sous</div
Distribution of antibiotic resistance genes across contrasted tropical agroecosystems in Réunion Island
No full textThis study presents the first exploratory assessment of antibiotic resistance genes (ARGs) and antibiotic residues in agricultural environments on Réunion Island, a French tropical territory in the south-western Indian Ocean. Sixteen samples from diverse matrices (manure, soil, water, and vegetables) across different agroecosystems were analyzed using high-throughput qPCR targeting 332 ARGs and chemical methods targeting 58 antibiotic compounds and trace elements. ARGs were widely detected across all matrices, with highest abundance observed in amended soils and manure. Surprisingly, ARG profiles, in terms of both abundance and average number, were comparable between unamended soils and natural soils. Antibiotic residues were found in only five manure and soil samples, with no clear correlation between the presence of these residues, trace elements and ARG abundance.Organic amendments significantly increased ARG levels in soils and non-metric multidimensional scaling revealed that ARG profiles clustered primarily by matrix type rather than by location. High-risk ARGs were widely prevalent, with 86% detected and 23% ubiquitous across all samples, and their occurrence in water and raw vegetables suggests potential human exposure through the food chain. This study highlights the influence of agricultural practices on environmental antimicrobial resistance in tropical island contexts and supports the need for expanded One Health surveillance integrating the environmental, animal and human compartments.</p
The weight of silent criteria: ESG score performance and investment attractiveness in sub-Saharan Africa
No full textInternational audienceThis article empirically examines the impact of ESG (Environmental, Social and Governance) scores on investment attractiveness in Sub-Saharan Africa, mobilizing a panel of data covering 40 countries over the period 2000-2023. The analysis is based on several econometric techniques, notably ordinary least squares (OLS) and generalized least squares (GLS), the results of which reveal a positive and statistically significant relationship between ESG performance and investment flows. The Kinky Least Squares (KLS) method was used to reinforce the robustness of the estimates and correct for potential endogeneity bias, confirming the robustness of the initial results. Furthermore, the inclusion of governance variables such as political stability, control of corruption and rule of law significantly enhances the attractiveness of the region's economies. These results suggest that improving ESG indicators, at both state and corporate levels, is a strategic lever for attracting investment in a sustainable way, and call for greater institutionalization of ESG practices in public policy and corporate reporting
« Parler sa langue ? » Les processus de revitalisation linguistique de l’occitan en France : entre subjectivation et désubjectivation
No full textInternational audienceOnce a prestigious idiom, Occitan in France is now considered one of Europe’s endangered regional and minority languages, even as it has been engaged for several decades in a movement for linguistic renewal. Yet the conditions under which revitalization processes have been unfolding for more than a generation within the Occitan-speaking community in France warrant closer examination. Following a brief overview of the history of regional languages in the French educational system—from the Ordinance of Villers-Cotterêts (1539) to the Molac Law (2021)—this study explores the status of Occitan today. Situated within a historical and sociolinguistic perspective, it examines the constraints and limitations of the contemporary Occitan linguistic renaissance through the lens of the theory of “apparatuses” (dispositifs) developed by the philosopher Giorgio Agamben, in order to assess the actual scope of Occitanist movements in France today, between processes of subjectivation (recomposition of the self) and desubjectivation (alienation within the apparatus).Autrefois idiome prestigieux, l’occitan en France fait désormais partie des langues régionales ou minoritaires menacées en Europe, mais il est également engagé depuis plusieurs décennies dans une démarche de renouveau linguistique. On peut toutefois s’interroger sur les conditions des processus de revitalisation à l’oeuvre depuis plus d’une génération dans la communauté occitanophone de France. Après un bref rappel de l’histoire des langues régionales au sein du système éducatif français depuis l’ordonnance de Villers-Cotterêts (1539) jusqu’à la loi Molac (2021), cette étude entend s’intéresser à la place qu’occupe l’occitan aujourd’hui. Menée dans une perspective historique et sociolinguistique, elle examine les contraintes et limites du renaissantisme linguistique occitan en les envisageant sous l’angle de la théorie des « dispositifs » développée par le philosophe Giorgio Agamben, pour tenter d’évaluer la portée réelle des mouvements occitanistes en France aujourd’hui, entre subjectivation (recomposition du « moi ») et désubjectivation (aliénation au dispositif)
Open Approach of Ascending Aorta Septic Rupture
No full textInternational audienceBackgroundSeptic pseudoaneurysms of the native ascending aorta are rare and challenging to treat, especially in elderly, comorbid patients with septic conditions and unfavorable anatomy for endovascular repair.Case SummaryA 78-year-old man with prior tricuspid valve replacement for endocarditis presented with methicillin-sensitive Staphylococcus aureus bacteremia. Imaging showed a large ascending aorta pseudoaneurysm, likely at the previous cardioplegia site. He underwent successful surgical repair via direct bovine pericardial patch closure under normothermic cardiopulmonary bypass. Recovery was uneventful.DiscussionEndovascular repair requires suitable anatomy, including adequate landing zones and small neck size, which were lacking here. Direct surgical patch repair offers a safe, effective, and less-invasive alternative to full aortic replacement, especially in septic, frail patients.Take-Home MessagesMultidisciplinary heart team discussion is essential to tailor management for complex septic aortic pseudoaneurysms. When endovascular treatment is unfeasible, direct surgical patch repair remains a safe and effective option in selected patients
Etude prédictive de la séroprévalence de Brucellose bovine en République centrafricaine.
No full textUne étude de la détection des anticorps anti-brucella dans le sang de vaches (prélevées dans divers marchés à bétail et zones de cantonnement de troupeaux à Bouar, Bambari, Bria et Damara) en République centrafricaine était effectuée. Au total, 468 échantillons de sang étaient prélevés dans des tubes secs. Après centrifugation et ou décantation, les échantillons de sérums étaient recueillis, centralisés et acheminés au laboratoire pour analyse. 466 sérums étaient soumis au test de Rose Bengal (RBT) pour détecter la présence d'anticorps spécifiques anti-brucella. La présence d'anticorps spécifiques dans le sérum, indique une exposition (infection) qui se traduit par une agglutination (liaison anticorps-antigènes). Les résultats montrent que 409 échantillons de sérums testés étaient négatifs soit 87,8 %, contre 12,2% d'échantillons positifs soit seulement 57 échantillons de sérums testés. Sur les 57 échantillons de sérums testés positifs, on notait une graduation de la positivité des résultats positifs ; 17 % étaient faiblement positif (+) 28 % moyennement positif (++) et 12%, fortement positif (+++). Ce qui indique une variabilité liée à l'existence des facteurs intrinsèques et extrinsèques. Bien que le Rose Bengal soit apprécié comme méthodes détection des anticorps anti Brucella abortus à cause de sa simplicité et sa rapidité, sa sensibilité est sans doute meilleure, mais influencée par des facteurs exogènes, elle doit néanmoins être complétée par d'autres analyses spécifiques afin de confirmer le diagnostic et la signification précise des cas cliniques.</div