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L’« asiento de negros » des Bourbons : un monopole de l’esclavage devenu l’instrument d’une alliance dynastique
No full textInternational audienceThe asiento is known in France as the contract by which the Spanish Monarchy authorized one or more privateers to engage in the slave trade to its American territories. It is naturally associated with the War of Spanish Succession, since it was a French company that benefited from it until 1713, when Great-Britain obtained it as part of the Utrecht negotiations. This monopoly was the object of much covetousness during the 17th century, as it was not only a contract organizing trade but also a diplomatic asset during negotiations.L’asiento est connu en France comme le contrat par lequel la monarchie espagnole autorisait un ou plusieurs particuliers à pratiquer la traite esclavagiste vers ses territoires américains. Il est naturellement associé à la guerre de Succession d’Espagne puisque c’est une compagnie française qui en bénéficie jusqu’en 1713, date à laquelle la Grande-Bretagne l’obtient dans le contexte des négociations d’Utrecht. Ce monopole fit l’objet de nombreuses convoitises au cours du XVIIe siècle car il n’est pas seulement un contrat organisant un commerce mais un atout diplomatique lors de négociations
Effect of the Laser Cleaning Process on the Surface State and the Fatigue Strength of a Ferritic Steel
No full textInternational audienceThe laser cleaning process is carried out on a ferritic steel for two configurations: a flat top beam profile on a squared-shaped laser spot and a Gaussian beam profile on a round-shaped laser spot. The two laser configurations induced fluence values of 0.20 and 0.27 J/cm2, respectively. An exhaustive characterization is then carried out, including microstructure, roughness, nanohardness and residual stresses, showing that the laser affected layer reaches a maximum depth of 90 µm. Fatigue tests were performed for each configuration, showing that the endurance limits remain unchanged in the stress range explored. This is attributed to the combination of negative effects (tensile residual stresses up to 354 MPa) and positive effects (grain refinement, increased nanohardness, reduced maximum valley depth
Harnessing thermal spring water and hydrophobic eutectic solvent for galactoglucomannans, glucans and phenolics recovery from Evernia prunastri and their potential biological applications
No full textInternational audienceLichens produce polysaccharides scarcely studied, in addition to secondary metabolites, that can exhibit high bioactivity. The aim of this work is to evaluate the efficiency of subcritical water extraction using thermal spring water and hydrophobic eutectic solvent for the extraction of these compounds. Subcritical water extraction of E. prunastri compounds was performed between 150 and 190 • C with distilled or with thermal spring water, combined or not with eutectic solvent men:lau as modifier. The biochemical composition of the polysaccharide extracts from each process (P-D for distilled water, P-T for thermal spring water, P-DM and P-TM when the eutectic was added) and of the soluble liquid extracts free from the precipitated polysaccharides (E-D, E-T, E-DM and E-TM) was analyzed as well as their antioxidant capacity and biological activity against herpes viruses. After purification through resin of E-T170 and E-TM150, extracts with an antioxidant activity of 1.38 and 1.78 g Trolox eq./ g of extract were obtained. Polysaccharides were identified as galactoglucomannans and glucans by NMR analysis. All polysaccharides were formulated in films, however, those extracted with thermal water presented much better viscoelastic properties than those extracted with distilled water. P-T-170 • C and P-TM-150 • C were non-irritating according to Skinethic® test but did not exhibit protective activity against HSV-1 and HSV-2 viruses. E-T170 • C presented a slightly higher antiviral activity (around 40 % protection) with low cytotoxicity. In addition, the films' physical and mechanical properties suggest potential for biomedical applications, especially in topical or mucosal delivery systems
The Mesolithic occupations of Jonquilles Cave (Caniac-du-Causse, Lot, France): First Interdisciplinary Results
No full textInternational audienceThis poster presents "Les Jonquilles", a newly discovered stratified Mesolithic cave found in 2018 in southwestern France. The site is located in a karstic area rich in dolina and caves, within a region known for its Mesolithic sites, including the Cuzoul de Gramat. Three main archaeological units have been identified: Early Mesolithic, Late Mesolithic, and a reworked Upper Palaeolithic layer. The Early Mesolithic occurs within a charcoal-rich deposit, while the Late Mesolithic corresponds to a thick ash layer. Micromorphological analysis indicates that post-depositional processes had a limited impact.Lithic material is scarce and often burnt, but armatures ranging from bitruncations to Montclus arrowheads attest to repeated occupations. Faunal remains are far more abundant, mostly burned and fragmented, and dominated by wild boar, red deer, and roe deer. A wide range of small and medium-sized fauna is also present, consistent with other Holocene assemblages in the region. Charcoal and seed analyses confirm the use of hazelnuts alongside other plant taxa. During the Late Mesolithic, oak forest was well developed, and, as observed at other sites, there appears to be a preference for a small number of woody taxa.Fire appears to have played a central role in the occupation of Jonquilles Cave. The archaeological record shows a very high proportion of thermoaltered flint and bone. Although no hearth structures have been identified, the thick ash sequence, exceeding 70 cm in the Late Mesolithic, suggests intense burning events. The significance of these fire-related activities remains to be clarified."Les Jonquilles" represents an important addition to the Mesolithic record of the Quercy and provides new opportunities to discuss site complementarity and settlement patterns on a regional scale
Multiblock Metabolomics Responses of the Diatom Phaeodactylum tricornutum Under Benthic and Planktonic Culture Conditions
No full textInternational audienceThis study investigates the metabolic responses of the model diatom Phaeodactylum tricornutum under different growth conditions, comparing benthic (adherent) and planktonic states. Using a multiblock metabolomics approach combining LC-HRMS2, NMR, and GC-MS techniques, we compared the metabolome of P. tricornutum cultivated on three laboratory substrates (glass, polystyrene, and polydimethylsiloxane) and under planktonic conditions. Our results revealed metabolic differences between adherent and planktonic cultures, particularly concerning the lipid and carbohydrate contents. Adherent cultures showed a metabolic profile with an increase in betaine lipids (DGTA/S), fatty acids (tetradecanoic and octadecenoic acids), and sugars (myo-inositol and ribose), suggesting modifications in membrane composition and lipid remodeling, which play a potential role in adhesion. In contrast, planktonic cultures displayed a higher content of cellobiose, specialized metabolites such as dihydroactinidiolide, quinic acid, catechol, and terpenes like phytol, confirming different membrane composition, energy storage capacity, osmoregulation, and stress adaptation. The adaptative strategies do not only concern adherent and planktonic states, but also different adherent culture conditions, with variations in lipid, amino acid, terpene, and carbohydrate contents depending on the physical properties of the support. Our results highlight the importance of metabolic adaptation in adhesion, which could explain the fouling process
Assessment of the Environmental Significance of Heavy Metals Pollution in Surficial Sediments of South Brittany Waters, France: An Ecological Risk Assessment Approach
No full textInternational audienceDistribution patterns of selected heavy metals content in sediments from the Bay of Quiberon and Gulf of Morbihan were studied to understand the current heavy metals contamination due to urbanization and mariculture activities in the coastal area. Therefore, a survey was conducted and 196 sediments collected were characterized for heavy metals content using Inductively Coupled Plasma -Mass Spectrometry (ICP-MS) after mix acid digestion process.The distribution maps of the concentrations of the heavy metals studied were produced as an isopleth map based on data interpolation by the ArcGIS software application. The association with the adverse effects on aquatic organisms was determined by the classification of the sediment according to the sediment quality guidelines. Therefore, two approaches were employed namely; direct comparison with Sediment Quality Guidelines (SQGs) by USEPA and comparison with other numerical SQGs, threshold effect level/probable effect level, and effect range low /effect range medium. In order to estimate the effect of multiple contaminations of heavy metals, the mean-ERM-quotient was calculated at each sampling point.</div
Generalized amoebas for subvarieties of
No full textThis paper is a report based on the results obtained during a three months internship at the University of Pittsburgh by the first author and under the mentorship of the second author. The notion of an amoeba of a subvariety in a torus has been extended to subvarieties of the general linear group by the second author and Manon. In this paper, we show some basic properties of these matrix amoebas, e.g. any such amoeba is closed and the connected components of its complement are convex when the variety is a hypersurface. We also extend the notion of Ronkin function to this setting. For hypersurfaces, we show how to describe the asymptotic directions of the matrix amoebas using a notion of Newton polytope. Finally, we partially extend the classical statement that the amoebas converge to the tropical variety. We also discuss a few examples. Our matrix amoeba should be considered as the Archimedean version of the spherical tropicalization of Tevelev-Vogiannou for the variety regarded as a spherical homogeneous space for the left-right action of
Quand les « profs de gym » étaient naturistes. La nature au secours de l’éducation en temps de crise (1936-1948)
No full textInternational audienceLa période 1936-1948 est riche tant en crises qu’en ruptures. Pour autant, elle n’est pas exempte de continuités. Le recours à la nature dans les programmes scolaires d’éducation physique en est une des illustrations. Partant de ce premier constat, il s’agit d’interroger la place mais surtout le rôle conféré à la nature au sein de l’école, en particulier, en éducation physique. Plus précisément, quelle attention réserve-t-on aux discours et aux pratiques de ceux qui prônent alors un retour salvateur à la nature, autrement dit les naturistes ? Parmi l’éventail des propositions naturistes existantes, quels choix font les acteurs de l’école ? Pour ce faire, un large corpus de sources (textes officiels, revues, ouvrages d’époque) a été mobilisé. Concernant les résultats, on montrera que les thèses et les pratiques naturistes s’imposent au sein de l’éducation physique scolaire lors de cette période de crise. Celles-ci n’échappent pas cependant à un processus de sélection et de transposition scolaires. Elles sont mises ainsi au service d’usages éducatifs fort différents sous-tendant des projets politiques et culturels antagonistes. Quoi qu’il soit, c’est le naturisme d’Hébert et du Dr Carton qui tire le mieux son épingle du jeu
