L'autre élection présidentielle: les groupes d'intérêt en campagne

National audienceUne tradition d'analyse américaine permet d'étudier les élections comme des conjonctures où les groupes d'intérêt agissent. A priori cette tradition est étrangère au cas français. Pourtant elle offre un cadre original et stimulant pour comprendre les campagnes électorales. C'est là le pari que nous avons fait pour les élections présidentielles et législatives françaises de 2012. A partir d'une question centrale (comment les groupes d'intérêt français agissent-ils pendant une campagne électorale ?), le protocole d'enquête élaboré ouvre une nouvelle perspective sur les élections françaises. Ce chapitre présente le protocole et les premiers résultats obtenus

Mercury(II) Trace Detection Using a Glassy Carbon Electrode Functionalized by Chemically Prepared Gold Nanoparticles. Influence of Coating Process on Surface Reactivity and Analytical Performances

An electrochemical sensor dedicated to Hg(II) trace detection was elaborated based on a gold nanoparticles (AuNPs) modified glassy carbon (GC) electrode. AuNPs were prepared using the Turkevich method and deposited on GC by drop casting. Different protocols including suspension filtration and evaporation temperature control were tested and their influence both on coating morphology and electrochemical activity assessed. From structural characterization, it can be concluded that neither the filtration step nor the drop evaporating temperature have a significant impact on coating morphology at the mesoscale level. However, regarding to the electrochemical activity of the functionalized electrodes, results showed that when some heterogeneities due to (AuNPs) aggregation were present in the coating, the electrochemical activity was reduced. Contrary to what was observed in our previous studies dealing with electrodeposited AuNPs, cycling an AuNPs-GC electrode in H2SO4 lead in all cases to a decrease in active surface area and in a higher density of surface defects, thus revealing a higher surface reactivity of chemically-synthesized AuNPs. The electrochemical activation procedure was found to influence the analytical performances of the functionalized electrode with respect to Hg(II) assay in the picomolar range, but not in the nanomolar range, as a consequence of a saturated concentration effect. A linear concentration range was obtained between 2 and 12 pM with a normalized sensitivity of 0.296 μA pM-1 min-1 using square wave anodic stripping voltammetry (SWASV) as the detection mode. A limit of detection (LOD) down to 1 pM was reached

Solid state NMR characterization of phenylphosphonic acid encapsulated in SBA-15 and aminopropyl-modified SBA-15

5th International Conference of theă Federation-of-European-Zeolite-Associations (FEZA), Valencia, SPAIN, JULă 03-07, 2011International audienceWe present in this communication that phenyl phosphonic acid can be efficiently loaded in mesoporous SBA-15 and aminopropyl-modified SBA powdered samples through the incipient wetness impregnation method. High amount of phosphonic acid can be reach up to 380 mg/g of sample. We use multinuclear solid state NMR as a method of choice for the indeep characterization of the samples. Thus we demonstrate that phosphonic acid molecules do not crystallize inside the pores. The molecules are highly mobile in SBA-15 because they are submitted to a confinement effect due to the mesoscopic size of the pores and consequently they exhibit a weak interaction with the silica walls. In the case of aminopropyl-modified SBA material, we show that the molecules are rigid and that they are in strong interaction with the aminopropyl groups. Moreover, a 2D double quantum 1H NMR experiment recorded at high field and high spinning speed permit to propose a model of the phosphonate-aminopropyl interaction. The increase in spectral resolution due to the combination of high magnetic field and fast MAS rate allows also the assignment of 1H resonances in aminopropyl-modified SBA matrix and notably allows the assignment of the protons resonance of the amino group

A Molecular Picture of the Adsorption of Glycine in Mesoporous Silica through NMR Experiments Combined with DFT‑D Calculations

International audienceThe adsorption behavior of the amino acid glycine in mesoporous silica has been investigated using a combination of quantum chemical calculations and NMR spectroscopy experiments. Glycine adsorption on two representative sites of an amorphous silica surface, vicinal silanols and a silanol nest, was investigated by DFT-D. The effect of water coadsorption on the energetics of adsorption and NMR shifts was characterized. It was found that the silanol nest is a more favorable site for glycine adsorption due to a local increased H-bond density. Co-adsorption with water is also favored, especially a water molecule between a SiOH and the ammonium moiety. NMR chemical shifts computed on these models fall into the observed 13C and 15N experimental range, suggesting that the presence of different energetically comparable adsorption configurations cannot be excluded

Commit-Chains: Secure, Scalable Off-Chain Payments

Current permissionless blockchains suffer from scalability limitations. To scale without changing the underlying blockchain, one avenue is to lock funds into blockchain smart-contracts (collateral) and enact transactions outside, or off- the blockchain, via accountable peer-to-peer messages. Disputes among peers are resolved with appropriate collateral redistribution on the blockchain. In this work we lay the foundations for commit-chains, a novel off-chain scaling solution for existing blockchains where an untrusted and non-custodial operator commits the state of its user account balances via constant-sized, periodic checkpoints. Users dispute operator misbehavior via a smart contract. The commit-chain paradigm enables for the first time that off-chain users can receive payments while being offline. Moreover, locked funds can be managed efficiently at constant communication costs, alleviating collateral fragmentation. We instantiate two account-based commit-chain constructions: NOCUST, based on a cost-effective challenge-response dispute mechanism; and NOCUST-ZKP, which provides provably correct operation via zkSNARKs. These constructions offer a trade-off between correctness, verification, and efficiency while both are practical and ensure key properties such as balance safety; that is, no honest user loses coins. We implemented both constructions on a smart contract enabled blockchain. Our evaluation demonstrates that NOCUST\u27s operational costs in terms of computation and communication scale logarithmically in the number of users and transactions, and allow very efficient lightweight clients (a user involved in e.g. 100 daily transactions only needs to store a constant 46 kb of data, allowing secure payments even on mobile devices). NOCUST is operational in production since March 2019

Controlling the order of triblock copolymer via confinement induced by forced self-assembly

We report the making of multilayered self-assembled films by coextrusion, composed of alternated layers of confining polycarbonate and confined poly(styrene-. b-butadiene-. b-methyl methacrylate), whose blocks are chemically different from the confining polymer, and presenting a self-assembled morphology directly after extrusion. The triblock copolymer layers thicknesses was varied from few hundreds to few tens of nanometers. As the triblock layer thickness is decreased and the draw ratio is increased, the triblock morphology is constrained into a preferential orientation and higher long-range order is observed by transmission electron microscopy and small angle X-ray scattering. This one-step and industrially scalable method allowing long-range ordering of the nanodomains is of interest for many engineering applications for which producing large quantity of materials is necessary

Méthodes mixtes, jeux, matériel ouvert et traduction en santé

Breathing Games est une communauté internationale qui crée des jeux et capteurs librement reproductibles pour la santé respiratoire et mentale. Nous proposons un retour d’expérience sur les succès et défis rencontrés depuis l’affiche présentée en 2017. Co-création : de la compliance à l’adhésion thérapeutique. Participation aux études cliniques : limiter l’investissement. Traductions des jeux : meilleure accessibilité des contenus. Commun en accès libre : autonomie et appartenance. Protocole : gestion de maladie ou santé publique critique ? Matériel : choix d’une éthique inclusive

Introduction to special section: Building complex and realistic geological models from sparse data

International audienceEarth scientists have always created spatial models of the subsurface. Before the dawn of computer-based modeling, earth models were simply drawn by hand on a piece of paper as cross section or plan views, sometimes utilizing the techniques of descriptive geometry. These hand-draw models are quick and easy to create; this is why we are still doing them on white boards, note books and sometimes even on napkins. They communicate ideas very well, but they are subjective and rarely constrained by data in a measurable way. As the number of observations grew with the advancement of data collections technologies, the possibility to use mathematical algorithms to do the modeling became a reality. These processes, first applied in 2D then in 3D, removed some of the subjectivity from the modeling. These processes work very well when the data density is high enough, meaning that models built with different mathematical methods are both realistic and similar one to another

Solid-state nuclear magnetic resonance: A valuable tool to explore organic-inorganic interfaces in silica-based hybrid materials

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