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Visionnage de teen series d’hier et d’aujourd’hui par des élèves en dernière année de secondaire :appropriations différenciées des messages sur les sexualités
No full textInternational audienc
La plaquette du cinquantenaire de la maison Christofle par Oscar Roty (1892-1895)
No full textCarnet Hypothèses "Au revers de la médaille" [https://medaille.hypotheses.org
Plasmonic-enhanced fluorescence measurements within an optofluidic photonic crystal fiber
No full textInternational audienceWe report the optimization of plasmonic-enhanced fluorescence (PEF) within an optofluidic photonic crystal fiber (PCF) for biosensing applications. This novel approach integrates silica-coated gold nanoparticles inside the inner walls of the PCF to enhance the signal of Cyanine 5 dye by associating the plasmonic enhancement of the fluorescence and the increased interaction length between the evanescent light and the analyte. This integration offers a robust solution for building a highly -sensitive detection platform. The thickness of the silica shell was optimized for maximizing the fluorescence enhancement while preventing fluorescence quenching effects. This study also investigates how the enhancement factor varies with different dye concentrations, resulting in a 150-fold enhancement under optimized conditions, demonstrating the system's sensitivity and versatility. As a proof-of-concept model application, we have also demonstrated the detection of micro-RNA tagged with a fluorophore using a complementary DNA anchored within the PCF. We envision that the successful demonstration of PEF within a PCF probe could potentially translate into a highly sensitive optofluidic platform for biomarker detection.</div
Teaching Mathematics with History: New Classifications and Classroom Experiments
No full textInternational audienc
Un 2e contact pour qui ? Entre travail et risque sanitaire, résoudre l'équation mémorielle du CEP
No full textInternational audienceLa prise en compte de la mémoire du travail permet de rééquilibrer une équation dans laquelle cette dimension était devenue une inconnue, empêchant de considérer les ressources perçues comme la rétribution d’une activité professionnelle et non comme celle du risque. C’est toute la force de la propagande et des moyens associés au CEP et l’asymétrie d’une entreprise menée dans une société en situation coloniale, que d’avoir imposé l’idée d’une expérience professionnelle synonyme de facilité, créant le souvenir d’un âge d’or, dont les bénéficiaires doivent supporter en compensation la révélation du risque sanitaire. Les anciens travailleurs corroborent en partie cette idée lorsqu’ils abordent la prise en charge (hébergement, restauration, etc.) dont ils ont bénéficié ; ils résistent davantage à cette logique compensatoire lorsqu’on aborde le sujet de la famille, de l’éloignement, et pour beaucoup aussi de la pénibilité
Genetic deregulation of REL in germinal center B cells induces generation of a pool of lymphoma precursor cells
No full textInternational audienceIn diffuse large B-cell lymphomas (DLBCLs), gains and amplifications of the 2p15-16 region, which always encompass the REL gene, are mostly restricted to the germinal center (GC) B-cell DLBCL subtype (GCB-DLBCL) for which c-Rel is the pivotal Rel/NF-kappa and Vcy; subunit. Although REL plays a key role in the GC reaction, its contribution to GCB-DLBCLs remains unclear. To understand the role of REL in the very first steps of GCB transformation, that is, when B cells with deregulated REL are competing with other B cells during chronic antigenic stimulation, we have created a dual-color mouse model that allows to induce REL in a limited pool of activation-induced cytidine deaminase (AID)-imprinted B cells after immunization and to differentially stain AID-imprinted B cells that overexpress REL or not. Dysregulation of REL in AID-imprinted B cells was associated with nuclear c-Rel overexpression in GCs 14 days after immunization. Dysregulation of REL at the GCB stage promoted GCB expansion, which was associated with both class-switch recombination and plasma cell differentiation. REL overexpression conferred a long-term competitive advantage, allowing GC persistence and continuous recirculation of REL-overexpressing B cells. IgHV dominance was increased at the messenger RNA level in REL-overexpressing B cells and clonal expansion was detected at the DNA level in some cases. Highlighting the role of the immune response, our results demonstrate the advantage conferred by REL in the GC competition and provide evidence that, as an oncogenic event of GCBs, its genetic deregulation induces the generation of a long-term pool of lymphoma precursor cells
Enhanced structural description of sodium vanadium phosphate glasses: A combined experimental and molecular dynamics study
No full textInternational audienceStructural and bonding insights into sodium vanadium phosphate (NVP) glasses are crucial for optimizing their performance as cathode materials in sodium-ion batteries. This study quantitatively assesses the structural features and bonding characteristics of two NVP glass compositions: (NaO)–(VO)–(PO) (α = 0.375, 0.285) with 0.375, 0.285. We combine experimental characterization (differential scanning calorimetry, X-ray diffraction and X-ray photoelectron spectroscopy,) and atomistic modeling (classical molecular dynamics (CMD), and Born–Oppenheimer molecular dynamics (BOMD)). This work provides a quantitative analysis of the different VO units in the two NVP glass models, superseding previous knowledge based largely on CMD simulations. Our results show that the account of the electronic structure, inherent in BOMD simulations is essential for capturing the Vsingle bondO bonding environment. This includes the splitting of the Vsingle bondO peak in the pair distribution function due to both short Vdouble bondO and longer Vsingle bondO bonds, a higher degree of polymerization in the phosphate network and a more significant role for V as a network former
INITIALIZATION-DRIVEN NEURAL GENERATION AND TRAINING FOR HIGH-DIMENSIONAL OPTIMAL CONTROL AND FIRST-ORDER MEAN FIELD GAMES
No full textThis paper first introduces a method to approximate the value function of high-dimensional optimal control by neural networks. Based on the established relationship between Pontryagin's maximum principle (PMP) and the value function of the optimal control problem, which is characterized as being the unique solution to an associated Hamilton-Jacobi-Bellman (HJB) equation, we propose an approach that begins by using neural networks to provide a first rough estimate of the value function, which serves as initialization for solving the two point boundary value problem in the PMP and, as a result, generates reliable data. To train the neural network we define a loss function that takes into account this dataset and also penalizes deviations from the HJB equation.In the second part, we address the computation of equilibria in first-order Mean Field Game (MFG) problems by integrating our method with the fictitious play algorithm. These equilibria are characterized by a coupled system of a first-order HJB equation and a continuity equation. To approximate the solution to the continuity equation, we introduce a second neural network that learns the flow map transporting the initial distribution of agents. This network is trained on data generated by solving the underlying ODEs for a batch of initial conditions sampled from the initial distribution of agents. By combining this flow approximation, the previously described method for approximating the value function, and the fictitious play algorithm, we obtain an effective method to tackle high-dimensional deterministic MFGs.</p