Portail HAL Um (Université de Montpellier)
Not a member yet
163190 research outputs found
Sort by
Characterization of Conus textile predatory venom by capillary electrophoresis hyphenated to mass spectrometry
No full textInternational audienc
Les formations agricoles dans le monde à l’épreuve de l’agroécologie
No full text[Articles publiés progressivement par la revue] Dans le cadre de l'approche des comparaisons internationales, ce dossier spécial de la revue Cahiers Agricultures vise à analyser les évolutions des curriculums des formations agricoles à travers le monde, tant dans les pays du Nord que du Sud, dans le contexte de montée en puissance des politiques de « transition agroécologique ». Il s'agit de comprendre les enjeux de l’élaboration des programmes des formations en agroécologie en fonction des définitions de l’agroécologie selon les contextes nationaux ou locaux, leur adoption et appropriation par les personnels de formation et leur réception par les publics concernés. Face à la prise de conscience croissante des enjeux environnementaux liés à l’agriculture, les politiques publiques réorientent les formations agricoles vers l’adaptation aux changements climatiques, la réduction d’usages des pesticides à travers l’intégration de nouveaux savoirs agronomiques en cours d’élaboration. Le premier axe propose d’interroger la manière dont les programmes d’enseignement (ou référentiels de formation) sont conçus pour répondre aux enjeux de la « transition agroécologique » (Métral, et all, 2016). Il s’agit d’analyser la traduction curriculaire des différentes conceptions de l’agroécologie. En effet, les définitions multiples de l’agroécologie (scientifique, politique, sociale, etc.), sa traduction en principes (HLPE 2019, FAO 2020, Wezel et al. 2020) se reflètent dans les contenus de formation, ce qui peut être source de tensions ou permettre au contraire d’intégrer une diversité de points de vue, de référentiels. Il s’agit aussi d’interroger les mécanismes qui permettent de sourcer plus rapidement les enseignements agronomiques sur les conditions d’activation d’innovations agroécologiques que documentent différents acteurs (recherche agronomique, organisations professionnelles, société civile). Le deuxième axe invite à examiner la manière dont les personnels de formation — enseignants, formateurs, conseillers, maîtres de stage — s’approprient et traduisent dans leurs pratiques pédagogiques ou professionnelles les référentiels et les orientations curriculaires liés à l’agroécologie (Gaborieau, Peltier, 2024). L’enjeu est de comprendre comment ces acteurs, situés à l’interface entre prescriptions institutionnelles et réalités locales, participent à la mise en œuvre effective des transformations attendues. Le troisième axe s’intéresse à la manière dont les publics en formation — élèves, étudiants, agriculteurs en reconversion, adultes en formation continue — reçoivent, interprètent et s’approprient (ou non) les savoirs agroécologiques transmis. L’objectif est d’analyser comment ces nouveaux contenus, porteurs de transformations profondes des pratiques agricoles, résonnent avec les trajectoires sociales (Sahuc, 2017), les représentations professionnelles et les projets de vie des apprenants
Culturable macroplastic-associated potential human pathogens in coral reef lagoons, Madagascar
No full textInternational audiencePotentially human pathogenic bacteria (PHPBs) have been detected in plastic-associated marine microbiomes, primarily through DNA-based methods. However, data on their culturability and concentrations on plastics remain limited, yet are essential to assess actual health risks. To address this gap, 70 floating macroplastic and 20 seawater samples were collected from two human-impacted reef lagoons in southwestern Madagascar (Atsimo-Andrefana region). PHPBs were cultured from their microbiomes using selective media and quantified. Macroplastics were predominantly polypropylene (34 %) and polyamide (31 %). In increasing order of concentration, four culturable PHPBs, Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, and Vibrio Harveyi clade species, were identified on both macroplastics and in seawater, across all sites and polymer types. Notably, 52 % of macroplastic samples harbored two PHPB species simultaneously, while only 7 % were PHPB-free. Concentrations of all PHPBs were consistently and significantly higher on macroplastics than in seawater, regardless of the measurement unit or polymer type, with the Vibrio Harveyi clade being the most abundant. No significant correlations were observed among PHPB species concentrations, suggesting limited interaction and independent colonization. These findings indicate that floating macroplastics may serve as reservoirs and fomites for viable PHPBs. However, their potential impacts on ecosystems and human health should be interpreted cautiously. We emphasize the need to contextualize PHPB concentration data by considering factors such as exposure pathways, environmental persistence, and bacterial virulence, rather than relying solely on concentration-based comparisons, which may lead to misinterpretation
Selective Supra-Aortic Trunk Stenting During Endovascular Total Aortic Arch Repair in Patients With Residual Chronic Type A Dissection Treated With Double-Fenestrated Physician-Modified Endografts
No full textInternational audienceObjective: To assess the impact of selective supra-aortic trunk (SAT) stenting on aortic remodeling in patients with chronic type A aortic dissection (cTAAD). Methods: Patients treated from 2017 to 2024 with aortic arch repair using double-fenestrated physician-modified endografts (PMEGs) for cTAAD were retrospectively analyzed. The objectives are to compare aortic treatment and remodeling, SAT evolution, and overall outcomes according to SAT dissection status (before and after), total aortic arch repair using a double-fenestrated PMEG. Results: Among 42 cTAAD patients treated, 30 had SAT dissection. Thirty-five patients received a standard PMEG, while 7 underwent additional selective SAT stenting (3 LCCA, 1 brachiocephalic trunk (BT), 4 right subclavian artery (RSA), and 3 right common carotid artery (RCCA)). Technical success was 100%. At 30 days, 1 patient died from stroke, 1 from pneumonia post-discharge. During a median follow-up of 18.5 months (IQR: 38.8), no type Ia endoleaks occurred. Six type Ic endoleaks were observed; 3 patients underwent reintervention, while the remaining 3 were monitored with follow-up CT scans showing no evidence of aortic growth. Complete SAT dissection resolution occurred in 12 patients (40%), including 9 with standard PMEG. Positive aortic remodeling was seen in 32 patients (76%) with a median diameter reduction of −1% (IQR: 5.5%). Five patients died during mid-term follow-up, with no deaths related to the procedure. Positive aortic remodeling rates are 73% vs. 83% (p=0.7) between patients with and without initial SAT dissection, 83% vs 92% (p=1) between patients with initially no SAT dissection and those who healed, 61% vs 88% (p=0.07) between patients with persistent SAT dissection and the others. Patients on curative anticoagulation or dual antiplatelet therapy showed reduced positive remodeling. Conclusion: Double-fenestrated PMEGs are effective for treating residual cTAADs, with high SAT healing and favorable remodeling. Persistent SAT dissection may hinder remodeling and require additional intervention. Clinical Impact Aortic arch repair using fenestrated physician-modified endografts without systematic SAT stenting reduces SAT manipulation and may lower stroke risk, while promoting a high rate of SAT and aortic dissection healing. In cases where SAT dissection persists and aortic growth is reported, secondary complementary SAT intervention can be performed to enhance aortic remodeling
Secret professionnel de l'avocat et retour de l'exercice des droits de la défense pour les saisies réalisées dans le cadre des opérations de visite domiciliaire
No full textInternational audienc
Beyond species means – the intraspecific contribution to global wood density variation
No full textInternational audienceWood density is central for estimating vegetation carbon storage and a plant functional trait of great ecological and evolutionary importance. However, the global extent of wood density variation is unclear, especially at the intraspecific level. We assembled the most comprehensive wood density collection to date, including 109 626 records from 16 829 plant species across woody life forms and biomes (GWDD v.2, available here: doi: 10.5281/zenodo.16919509 ). Using the GWDD v.2, we explored the sources of wood density variation within individuals, within species and across environmental gradients. Intraspecific variation accounted for c . 15% of overall wood density variation (SD = 0.068 g cm −3 ). Variance was 50% smaller in sapwood than heartwood, and 30% smaller in branchwood than trunkwood. Individuals in extreme environments (dry, hot and acidic soils) had higher wood density than conspecifics elsewhere (+0.02 g cm −3 , c . 4% of the mean). Intraspecific environmental effects strongly tracked interspecific patterns ( r = 0.83) but were 70–80% smaller and varied considerably among taxa. Individual plant wood density was difficult to predict (root mean square error > 0.08 g cm −3 ; single‐measurement R 2 = 0.59). We recommend (1) systematic sampling of multiple individuals and tissues for local applications, and (2) expanded taxonomic coverage combined with integrative models for robust estimates across ecological scales.La densidad de la madera es fundamental para estimar el almacenamiento de carbono vegetal y constituye un rasgo funcional de gran importancia ecológica y evolutiva. Sin embargo, el alcance global de la variación de la densidad de madera no está claramente descrito, especialmente a nivel intraespecífico. Recopilamos la colección más completa de densidad de madera hasta la fecha, que incluye 109 626 registros de 16 829 especies de plantas leñosas de diversas formas de vida y biomas (GWDD v.2, disponible aquí: doi: 10.5281/zenodo.16919509 ). Utilizando la GWDD v.2, exploramos las fuentes de variación en la densidad de la madera entre individuos y especies, así como a través de gradientes ambientales. La variación intraespecífica representó aproximadamente el 15% de la variación total de la densidad de la madera (SD = 0.068 g cm −3 ). La varianza fue un 50% menor en la albura que en el duramen, y un 30% menor en la madera de ramas que en la del tronco. Los individuos en ambientes extremos (secos, cálidos, suelos ácidos) presentaron una densidad de madera mayor que sus congéneres en otros lugares (+0.02 g cm −3 , ~4% de la media). Los efectos ambientales intraespecíficos siguieron estrechamente los patrones interespecíficos ( r = 0.83), sin embargo, resultaron entre un 70% y un 80% menores y variaron considerablemente entre los taxones. La densidad de madera por individuo fue difícil de predecir (RMSE >0.08 g cm −3 ; R 2 de medición única = 0.59). Recomendamos (1) el muestreo sistemático intraespecífico de múltiples individuos para aplicaciones locales y (2) una cobertura taxonómica ampliada combinada con modelos integradores para obtener estimaciones robustas a través de las escalas ecológicas.La densité du bois est essentielle pour estimer le stockage de carbone de la végétation et constitue un trait fonctionnel d’une grande importance écologique et évolutive. Cependant, l’ampleur de la variation globale de la densité du bois reste mal caractérisée, en particulier au niveau intraspécifique. Nous avons rassemblé la base de données la plus complète à ce jour sur la densité du bois, comprenant 109 626 mesures provenant de 16 829 espèces de plantes ligneuses appartenant à diverses formes de vie et biomes (GWDD v.2, disponible ici: doi: 10.5281/zenodo.16919509 ). À l’aide de la GWDD v.2, nous avons exploré les sources de variation de la densité du bois au sein des individus, au sein des espèces et le long de gradients environnementaux. La variation intraspécifique représentait environ 15% de la variation totale de la densité du bois (SD = 0,068 g cm −3 ). La variance était 50% plus faible dans l’aubier que dans le duramen, et 30% plus faible dans le bois des branches que dans celui du tronc. Les individus vivant dans des environnements extrêmes (secs, chauds, sols acides) présentaient une densité du bois plus élevée que leurs congénères ailleurs (+0,02 g cm −3 , soit ~4% de la moyenne). Les effets environnementaux intraspécifiques reflétaient les tendances interspécifiques ( r = 0,83), mais étaient 70 à 80% plus faibles et variaient considérablement entre taxons. La densité du bois à l’échelle individuelle était difficile à prédire (RMSE >0,08 g cm −3 ; R 2 = 0,59). Nous recommandons (1) un échantillonnage systématique de plusieurs individus et tissus pour les applications locales et (2) un élargissement de la couverture taxonomique combiné à des modèles intégratifs afin d’obtenir des estimations robustes à travers les échelles écologiques
Temperate phage evolve to integrate host stress and quorum signals in lysis-lysogeny decisions
No full textInternational audienceTemperate phage can transmit both horizontally (lytic cycle) and vertically (lysogenic cycle). Many temperate phage have the ability to modify their lysis/lysogeny decisions based on various environmental cues. For instance, many prophage are known to reactivate when SOS stress responses of their host are triggered. Temperate phage infecting Bacilli can also use peptide signals (“arbitrium”) to control their lysis/lysogeny decisions. However, information from the arbitrium and SOS systems can be potentially conflicting, and it is unclear how phage integrate information carried by these two different signals when making lysis–lysogeny decisions. Here, we use evolutionary epidemiology theory to explore how phage could evolve to use both systems to modulate lysis/lysogeny decisions in a fluctuating environment. Our model predicts that it can be adaptive for phage to respond to both host SOS systems and arbitrium signaling, as they provide complementary information on the quality of the infected host and the availability of alternative hosts. Using the phage phi3T and its host Bacillus subtilis , we show that during lytic infection and as prophage, lysis–lysogeny decisions rely on the integration of information on host condition and arbitrium signal concentrations. For example, free-phage are more likely to lysogenise a stressed host, and prophage are less likely to abandon a stressed host, when high arbitrium concentrations suggest susceptible hosts are unavailable. These experimental results are consistent with our theoretical predictions and demonstrate that phage can evolve plastic life-history strategies to adjust their infection dynamics to account for both the within-host environment (host quality) and the external environment that exists outside of their host (availability of susceptible hosts in the population). More generally, our work yields a new theoretical framework to study the evolution of viral plasticity under the influence of multiple environmental cues
Bridging Impulse Control of Piecewise Deterministic Markov Processes and Markov Decision Processes: Review and Open Challenges
No full textControl theory plays a pivotal role in understanding and optimizing the behavior of complex dynamical systems across various scientific and engineering disciplines. Two key frameworks that have emerged for modeling and solving control problems in stochastic systems are Piecewise Deterministic Markov Processes (PDMPs) and Markov Decision Processes (MDPs). Each framework has its unique strengths, and their intersection offers promising opportunities for tackling a broad class of problems, particularly in the context of impulse control and sequential decision-making for complex systems. The relationship between PDMPs and MDPs is a natural subject of exploration, as embedding impulse control problems for PDMPs into the MDP framework could open new avenues for their analysis and resolution. Specifically, this integration would allow leveraging the computational and theoretical tools developed for MDPs to address the challenges inherent in PDMPs. On the other hand, PDMPs can offer a versatile and simple paradigm to model continuous time problems that are often described as discrete-time MDPs parametrized by complex transition kernels. This transformation has the potential to bridge the gap between the two frameworks, enabling solutions to previously intractable problems and expanding the scope of both fields. This paper presents a comprehensive review of two research domains, illustrated through a running medical example. The example is revisited and progressively formalized within the framework of the various concepts and objects introduced
