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Synthèse des connaissances sur les fourmis (Hymenoptera, Formicidae) du Parc national des Écrins (SE France)
No full textInternational audienceSynthesis of knowledge on the ants (Hymenoptera, Formicidae) of the Écrins national park (SE France). The synthesis of 1686 occurrence data of ants (family Formicidae, Hymenoptera) identified to the species level, distributed across the entire Écrins National Park (core zone and adhesion zone) revealed 83 species, i.e. more than one third of the myrmecofauna of metropolitan France. The species ac- cumulation curve shows, however, that the completeness of the inventory is moderate. Although the first data date back to 1984, more than 90% of the data have been obtained since 2018. To remedy to the knowledge deficit, the park adopted a strategy in 2018 which consisted in: first mobilizing park agents for opportunistic collections throughout the territory and an association of ant specialists for identification, and second occasionally involving ant specialists in field surveys. This sampling effort allowed exploring the distribution of diversity and species according to the type of environment and to elevation, and to reveal the presence of species that could represent an issue for the park. In particular, Formica paralugubris Seifert, 1996, a species of redwood ant endemic to the western Alps and the Jura, very little known in France, was detected in several sites. This species being difficult to distinguish from Formica lugubris Zetterstedt, 1838 – a very common boreomontane species – the identification was based on a double diagnosis: morphological and molecular. The inventory revealed other remarkable species such as Leptothorax gredleri Mayr, 1855, a species from central and northern Europe whose only known station in France is the one in the park, and Leptothorax pacis (Kutter, 1945), a very rare species occurring mainly in the Alps and the Pyrenees. A conservation value analysis relying on a method specific to the park revealed Formica paralugubris as a species with a particularly high conservation value within the territory of the park.La synthèse de 1686 données d’occurrence de fourmis (famille des Formicidae, Hymenoptera) identifiées à l’espèce réparties sur l’ensemble du parc national des Écrins (zone cœur et zone d’adhésion) a permis de recenser 83 espèces, soit plus du tiers de la myrmécofaune de France métropolitaine. La courbe d’accumulation des espèces montre cependant que la complétude de l’inventaire des espèces est modérée. Bien que les premières données datent de 1984, plus de 90 % des données ont été obtenues depuis 2018. Face au déficit de connaissance d’avant 2018, la stratégie du parc, qui s’est avérée efficace, a d’abord été de mobiliser les agents du parc pour des collectes opportunistes sur l’ensemble du territoire et une association spécialiste des fourmis pour l’identification, puis de faire intervenir ponctuellement des spécialistes sur le terrain. Cette pression d’échantillonnage a permis d’explorer la distribution de la diversité et des espèces en fonction du type de milieu et de l’altitude, et de révéler la présence d’espèces pouvant constituer un enjeu pour le parc. En particulier, Formica paralugubris Seifert, 1996, une espèce de fourmis rousse des bois endémique de l’ouest des Alpes et du Jura, très peu connue en France, a été détectée dans plusieurs stations. Cette espèce étant difficile à distinguer de Formica lugubris Zetterstedt, 1838, une espèce boréo-montagnarde très commune, l’identification a porté sur un double diagnostic, morphologique et moléculaire. L’inventaire a révélé d’autres espèces remarquables telles que Leptothorax gredleri Mayr, 1855, une espèce d’Europe centrale et du nord dont la seule station connue en France est celle du parc, et Leptothorax pacis (Kutter, 1945), une espèce très rare présente essentiellement dans les Alpes et les Pyrénées. L’évaluation de patrimonialité selon une méthode propre au parc n’a révélé qu’une seule espèce à considérer comme patrimoniale pour le parc : Formica paralugubris
Chapitre 5. Pas de relationalité sans solidarité. La fabrique de la solidarité écologique : affects, relations et assemblages pour la gouvernance des territoires vivants
No full textChapitre 5International audienceCe chapitre interroge l’impasse des gouvernances environnementales fondées sur des savoirs abstraits, incapables de produire des actions transformatrices et de résoudre des conflits qui opposent des mondes vécus. En mobilisant les savoirs situés, l’affect, l’adaptation affective et la « connaissance qui affecte », les auteurs proposent de requalifier la solidarité écologique : d’un principe juridique et cognitif à un affect émergent. Par une approche deleuzo-guattarienne de l’assemblage, la solidarité devient une intensité ressentie de l’interdépendance, produite par l’alignement de perspectives hétérogènes (scientifique, agricole, cynégétique, conservationniste). L’étude des marais de Camargue montre comment des pratiques de co-production (gestion concertée de l’eau, pâturage, suivis partagés) peuvent générer un « monde commun » et ouvrir sur des dispositifs durables (pactes socio-écologiques, arènes délibératives des vivants). Elle plaide pour une gouvernance relationnelle, attentive aux médiations matérielles et sensibles, où faciliter la rencontre compte plus que décider, afin d’instituer la solidarité
Hydration mechanisms in Roman seawater concrete: Archaeological analogue for validation of long-term ageing reactive transport model
No full textInternational audienceCement-based materials are considered for sealing plugs in deep geological disposal of radioactive waste. Ensuring their long-term durability is critical for safety over millennia. The Roman Concrete (RoC) project uses ancient Roman underwater concretes as analogues to validate reactive transport models for long-term ageing.This study focuses on hydration mechanisms in Roman concrete made with Phlegrean pozzolan, slaked lime, and seawater. Various techniques (XRD, SEM-EDS, NMR, nanoindentation, microtomography, ICP-OES, ion chromatography) were used to characterize hydration products. Casting underwater led to aragonite and brucite layers with a 60 GPa Young's modulus, protecting the concrete from further degradation. In the core, pozzolanicreactions produce C-(A)-S-H phases (Ca/Si = 1.2; Al/Si = 0.2) with a modulus of 12 GPa. HYTEC modeling confirmed the mechanism: incongruent pozzolan dissolution releases ions (K+, SiO₄ 4− , Al3+, Na+), promoting C-(A)-S-H formation and portlandite consumption
Plant conservation in a changing Mediterranean world
No full textInternational audienceSocietal Impact Statement The Mediterranean is one of five climatic regions on the planet characterised by a prolonged summer drought, exceptional plant diversity and high rates of endemism. We provide a framework to link the ecology of plant species conservation in the context of rapid and extreme climate deregulation to a philosophical typology of temporal attitudes (i.e., past, present and future). We argue that we must go beyond the historical heritage approach to embrace conservation action in a changing world. We review pragmatic and original ways to deepen social awareness for plant conservation, aligned with the three temporal themes. It is time to bring plants to the forefront of conservation action. Summary In this Thomas Review, we provide a structure that links ecological science of plant species conservation to a philosophical typology of temporal attitudes of scientists, i.e. ways of considering the inscription of one's action in time, with a preference for a temporal dimension in the past, the present or the future. We developed this framework to illustrate original ways of deepening social awareness for plant conservation. In section 1, we widen ecological and evolutionary foundations for plant conservation based on the historical floristic heritage to embrace the need to protect species at their range limits and the need to monitor the effects of extreme climate events. The processes that shape diversity and adaptation are central to this approach. Section 2 describes three temporal attitudes associated with the above three conservation themes. The remembrance attitude is characterised by its interest in the long‐term history of plant diversity. The anticipation attitude relies on climate scenarios and expected species distribution changes. Finally, a prudent attitude consists of making regular observations of ongoing change that relies on an iterative temporality of a continually renewed present. In section 3, we illustrate pragmatic and original ways to deepen social awareness for plant conservation in line with the three temporal themes. We conclude with a comment on the uncertainties surrounding conservation science and the need for confidence to act locally.El Mediterráneo es una de las cinco regiones climáticas del planeta caracterizadas por una prolongada sequía estival, una diversidad vegetal excepcional y altos índices de endemismo. En un contexto de desregulación climática acelerada y extrema, proponemos un marco para vincular la ecología de la conservación de especies vegetales con una tipología filosófica de actitudes temporales (pasado, presente y futuro). Sostenemos que es necesario superar un enfoque rígido centrado en el patrimonio natural y estructurar acciones de conservación adecuadas a un mundo en transformación. Examinamos medios pragmáticos y originales para fortalecer la concientización social sobre la conservación de las plantas en relación con estas tres dimensiones temporales. Ha llegado el momento de situar a las plantas en el centro de las estrategias de conservación.La Méditerranée est l'une des cinq régions climatiques de la planète caractérisées par une sécheresse estivale prolongée, une diversité végétale exceptionnelle et des taux élevés d'endémisme. Dans un contexte de dérégulation climatique accélérée et extrême, nous proposons un cadre pour relier l'écologie de la conservation des espèces végétales, à une typologie philosophique des attitudes temporelles (passé, présent et futur). Nous défendons l'idée qu'il faut dépasser une approche figée du patrimoine naturel et structurer des actions de conservation dans un monde en mutation. Nous passons en revue des moyens pragmatiques et originaux de renforcer la sensibilisation sociale à la conservation des plantes, en lien avec ces trois dimensions temporelles. Le moment est venu de mettre les plantes au cœur des stratégies de conservation.Il Mediterraneo è una delle cinque regioni climatiche del pianeta caratterizzate da una siccità estiva prolungata, un'eccezionale diversità vegetale e alti tassi di endemismo. In un contesto di sregolamento climatico, rapido ed estremo, proponiamo un quadro per collegare l'ecologia della conservazione delle specie vegetali a una tipologia filosofica delle attitudini temporali (passato, presente e futuro). Sosteniamo che occorre superare un approccio statico al patrimonio naturale e strutturare azioni di conservazione in un mondo in trasformazione. Esaminiamo modalità pragmatiche e originali per rafforzare la consapevolezza sociale sulla conservazione delle piante, in relazione a queste tre dimensioni temporali. È giunto il momento di mettere le piante al centro delle strategie di conservazione
Ensuring colloidal stability of cisplatin-loaded mesoporous silica nanoparticles: from synthesis to cytotoxicity assays
No full textInternational audienceMesoporous silica nanoparticles (MSNs) have attracted significant attention as a promising drug delivery platform for cancer treatment. However, their colloidal stability often remains overlooked, despite the numerous drawbacks associated with its absence. In this study, the enhancement of the colloidal stability of thoroughly characterised (TEM, DLS, zeta potential, TGA, XRD, N 2 physisorption) monodisperse MCM-41 MSNs in physiological conditions through the grafting a comb-like copolymer was successfully accomplished (preservation of the hydrodynamic diameter and the polydispersity index for at least 3 days). The loading of a therapeutic agent, cisplatin, was then achieved (12 wt%) without compromising their colloidal stability, and drug release kinetics were evaluated in cell culture medium, observing a complete release of the cargo after 48 h. Cytotoxicity studies conducted before and after drug loading confirmed the innocuousness of unloaded MSNs and demonstrated cytotoxic effects comparable to those of free cisplatin for the loaded nanoparticles (IC 50 = 23 and 13 μM CDDP for loaded MSNs versus 24 and 11 μM CDDP for free cisplatin in, respectively, SW480 and A549 cell lines).Particular emphasis was placed on ensuring the reproducibility of the results (e.g., hydrodynamic diameter and polydispersity index were measured across 49 independent synthesis) and on thoroughly evaluating the colloidal stability of the nanoparticles throughout the study, from synthesis to cytotoxicity assays. To the best of our knowledge, this work represents the first systematic study of the conditions required to develop stable colloidal suspensions of monodispersed mesoporous silica nanoparticles loaded with cisplatin, achieving high reproducibility, which constitutes a novel and robust contribution to the field.</p
A nationwide 12‐month observatory of automated insulin delivery shows improved glucose control, sustained adoption, and reduced acute severe events
No full textInternational audienceAims: A nationwide observational study was conducted to assess the 12-month effectiveness of AID systems in the routine care of people with Type 1 diabetes (PwT1D).Methods: All PwT1D, adults, and children, who initiated AID between January 1, 2022, and December 31, 2022, were included across 79 centres. Clinical data, continuous glucose monitoring (CGM) parameters, acute severe events in the last year, and HbA1c levels were collected at AID initiation, and after 3, 6, and 12 months of AID treatment. Median values [interquartile range, IQR] and % PwT1D with acute severe events were reported. The primary outcome was the change in time in range (TIR; 3.9-10 mmol/L) after 1 year with AID.Results: A total of 2741 PwT1D were included: 44.4% male, age 38 years [29], BMI 24.5 kg/m2 [6.7], diabetes duration 19 years [20]. AID systems were MiniMed 780G in 49.7%, Tandem Control-IQ in 49.3%, others in 1%. After 12 months, TIR increased from 58.0 [21] to 70.1% [14] while HbA1c levels decreased from 7.6 [1.2] to 7.0% [0.8]. Percent PwT1D experiencing severe hypoglycaemia (SH) decreased from 4.1 to 0.9%, and ketoacidosis from 1.2 to 0.6%. All improvements were observed after 3 months, sustained through 12 months, and statistically significant (p < 0.05). Only 2.8% of PwT1D discontinued AID.Conclusions: Twelve months of AID use in routine care improved glucose control in PwT1D, among whom there was less experienced SH and a minor discontinuation
Short note: on the determination of the relaxation time distributions using Bézier curves
No full textInternational audienceFor the interpretation of spectral induced polarization spectra, the determination of the relaxation time distributions (RTD) can be useful, for instance to extract the grain size distribution. However, this is an ill-posed problem, and retrieving the RTD often requires regularization during the inversion process. In this note, we use Bézier curves and simulated annealing to determine the RTD. The procedure that does not require any regularization nor smoothing, by reducing the number of parameters thanks to Bézier curves which are intrinsically continuous and infinitely derivable. We successfully applied our methodology to three examples (Cole–Cole model, Davidson–Cole model, and an experimental spectrum), demonstrating its interest and efficiency
Emotions et dispositifs participatifs en recherche-action sur la transition écologique : risques de normalisation des émotions et de tarissement de la critique sociale ?
No full textInternational audienceCet article examine un dispositif participatif de recherche-action sous l’angle des émotions impliquées dans la transition écologique de la Camargue (Bouches-du-Rhône, France). Il questionne les éventuelles limites que ce type de dispositif impose à la prise en compte des émotions dans les débats et la réflexion collective. Différents processus micro-interactionnels et organisationnels sont pointés comme conduisant à un filtrage émotionnel avec pour conséquences de favoriser une conception technique et téléologique de la transition écologique, de limiter la critique sociale et d’inciter une normalisation des émotions citoyennes et de leurs modalités d’expression
Interacting drivers of Holocene climate change in southwestern Africa: the influence of insolation, rainbelt dynamics and upwelling
No full textInternational audienceUnderstanding regional-scale patterns of long-term climate variability is essential for identifying the drivers of past environmental change. In southern Africa, the continent is often divided into three rainfall zones-summer, winter, and aseasonal-but this framework fails to capture the finer dynamics of transitional areas where tropical, subtropical, and temperate systems converge. This study examines Holocene climate variability along the western margin of the southern African monsoon region using a new 7300-year nitrogen isotope record from rock hyrax middens at Omanyne-4 in northern Namibia. Unlike other Namib Desert records that indicate progressive aridification through the Holocene, the Omanyne-4 sequence shows a long-term trend toward increasing humidity, consistent with insolation-driven enhancement of tropical and Indian Ocean moisture advection. Comparisons with records from northern Namibia, Botswana, and western Zambia reveal a coherent pattern of mid-to late Holocene humidification across the northwestern interior, in contrast to coastal aridification. Periods of both in-phase and antiphase variability with other regional records highlight the role of the Angola-Benguela Front and associated upwelling dynamics in modulating Namibian hydroclimate. These results delineate distinct Holocene climate response regions in northern Namibia and Botswana and demonstrate the non-linear nature of regional responses to insolation forcing and underscore the importance of coastal-inland atmospheric interactions in shaping long-term hydroclimate variability in southwestern Africa.</div
