Du bricolage chez Picasso? : Étude materielle et technique de trois carnets de l’epoque cubiste

Este artículo efectúa un análisis material y técnico de tres cuadernos insólitos de Picasso que datan de la época cubista: MP 1859 del invierno 1906-1907, MP 1862 de mayo-junio de 1907 y MP 1990-98 de 1915. Estos tres cuadernos, conservados en el museo nacional Picasso de París parecen, en efecto, haber sido realizados a mano por un aficionado, puede ser incluso que por Picasso mismo. Se trata, así, gracias al peritaje de dos conservadoras-restauradoras, de determinar los procesos de fabricación de estos cuadernos para volver a situarlos en el corpus general de los cuadernos de Picasso, y la materialidad de estos objetos de trabajo. Este estudio se esfuerza así por demostrar la importancia de la historia material y técnica en la historia del arte, tanto para comprender las obras como para inscribirlas en su contexto histórico de fabricación, marcado por las prácticas creativas corrientes. En efecto, el último tercio del siglo XIX vio desarrollarse múltiples hobbies creativos de aficionados que han dejado una huella sobre el cubismo, la invención de los papiers collés y de las construcciones.Cet article effectue une analyse matérielle et technique de trois carnets insolites de Picasso datant de l’époque cubiste: MP 1859 de l’hiver 1906-1907, MP 1862 de mai-juin 1907, et MP 1990-98 de 1915. Ces trois carnets, conservés au musée national Picasso de Paris, semblent en effet avoir été réalisés à la main par un amateur, peut-être même par Picasso lui-même. Il s’agit ainsi, grâce à l’expertise de deux conservatrices-restauratrices, de déterminer les procédés de fabrication de ces carnets pour les replacer dans le corpus plus général des carnets de Picasso et la matérialité de ces objets de travail. Cette étude s’attache ainsi à démontrer l’importance de l’histoire matérielle et technique en histoire de l’art, tant pour comprendre les œuvres que pour les inscrire dans leur contexte historique de fabrication marqué par les pratiques créatives ordinaires. En effet, le dernier tiers du XIXe siècle voit se développer de multiples loisirs créatifs amateurs qui ont laissé leur empreinte sur le cubisme, l’invention des papiers collés et des construction

Clostridium sticklandii, a specialist in amino acid degradation:revisiting its metabolism through its genome sequence.

International audienceBACKGROUND: Clostridium sticklandii belongs to a cluster of non-pathogenic proteolytic clostridia which utilize amino acids as carbon and energy sources. Isolated by T.C. Stadtman in 1954, it has been generally regarded as a "gold mine" for novel biochemical reactions and is used as a model organism for studying metabolic aspects such as the Stickland reaction, coenzyme-B12- and selenium-dependent reactions of amino acids. With the goal of revisiting its carbon, nitrogen, and energy metabolism, and comparing studies with other clostridia, its genome has been sequenced and analyzed. RESULTS: C. sticklandii is one of the best biochemically studied proteolytic clostridial species. Useful additional information has been obtained from the sequencing and annotation of its genome, which is presented in this paper. Besides, experimental procedures reveal that C. sticklandii degrades amino acids in a preferential and sequential way. The organism prefers threonine, arginine, serine, cysteine, proline, and glycine, whereas glutamate, aspartate and alanine are excreted. Energy conservation is primarily obtained by substrate-level phosphorylation in fermentative pathways. The reactions catalyzed by different ferredoxin oxidoreductases and the exergonic NADH-dependent reduction of crotonyl-CoA point to a possible chemiosmotic energy conservation via the Rnf complex. C. sticklandii possesses both the F-type and V-type ATPases. The discovery of an as yet unrecognized selenoprotein in the D-proline reductase operon suggests a more detailed mechanism for NADH-dependent D-proline reduction. A rather unusual metabolic feature is the presence of genes for all the enzymes involved in two different CO2-fixation pathways: C. sticklandii harbours both the glycine synthase/glycine reductase and the Wood-Ljungdahl pathways. This unusual pathway combination has retrospectively been observed in only four other sequenced microorganisms. CONCLUSIONS: Analysis of the C. sticklandii genome and additional experimental procedures have improved our understanding of anaerobic amino acid degradation. Several specific metabolic features have been detected, some of which are very unusual for anaerobic fermenting bacteria. Comparative genomics has provided the opportunity to study the lifestyle of pathogenic and non-pathogenic clostridial species as well as to elucidate the difference in metabolic features between clostridia and other anaerobes

Extended analysis of the Z2-FET: Operation as capacitor-less eDRAM

This article has been accepted for publication by IEEE "Navarro Moral, C.; et al. Extended analysis of the Z2-FET: Operation as capacitor-less eDRAM. IEEE Transactions on Electron Devices, 64(11): 4486-4491 (2017). DOI: 10.1109/TED.2017.2751141(c) 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works."The Z2-FET operation as capacitorless DRAM is analyzed using advanced 2-D TCAD simulations for IoT applications. The simulated architecture is built based on actual 28-nm fully depleted silicon-on-insulator devices. It is found that the triggering mechanism is dominated by the front-gate bias and the carrier’s diffusion length. As in other FB-DRAMs, the memory window is defined by the ON voltage shift with the stored body charge. However, the Z2-FET’s memory state is not exclusively defined by the inner charge but also by the reading conditions

Material characterization and finite element modelling of cyclic plasticity behavior for 304 stainless steel using a crystal plasticity model

Low cycle fatigue tests were carried out for a 304 stainless steel at room temperature. A series of experimental characterisations, including SEM, TEM, and XRD were conducted for the 304 stainless steel to facilitate the understanding of the mechanical responses and microstructural behaviour of the material under cyclic loading including nanostructure, crystal structure and the fractured surface. The crystal plasticity finite element method (CPFEM) is a powerful tool for studying the microstructure influence on the cyclic plasticity behaviour. This method was incorporated into the commercially available software ABAQUS by coding a UMAT user subroutine. Based on the results of fatigue tests and material characterisation, the full set of material constants for the crystal plasticity model was determined. The CPFEM framework used in this paper can be used to predict the crack initiation sites based on the local accumulated plastic deformation and local plastic dissipation energy criterion, but with limitation in predicting the crack initiation caused by precipitates

Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

This paper presents measurements of the $W^+ \rightarrow \mu^+\nu$ and $W^- \rightarrow \mu^-\nu$ cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13

Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

Search for chargino-neutralino production with mass splittings near the electroweak scale in three-lepton final states in √s=13 TeV pp collisions with the ATLAS detector

A search for supersymmetry through the pair production of electroweakinos with mass splittings near the electroweak scale and decaying via on-shell W and Z bosons is presented for a three-lepton final state. The analyzed proton-proton collision data taken at a center-of-mass energy of √s=13  TeV were collected between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider, corresponding to an integrated luminosity of 139  fb−1. A search, emulating the recursive jigsaw reconstruction technique with easily reproducible laboratory-frame variables, is performed. The two excesses observed in the 2015–2016 data recursive jigsaw analysis in the low-mass three-lepton phase space are reproduced. Results with the full data set are in agreement with the Standard Model expectations. They are interpreted to set exclusion limits at the 95% confidence level on simplified models of chargino-neutralino pair production for masses up to 345 GeV

Organised Genome Dynamics in the Escherichia coli Species Results in Highly Diverse Adaptive Paths

The Escherichia coli species represents one of the best-studied model organisms, but also encompasses a variety of commensal and pathogenic strains that diversify by high rates of genetic change. We uniformly (re-) annotated the genomes of 20 commensal and pathogenic E. coli strains and one strain of E. fergusonii (the closest E. coli related species), including seven that we sequenced to completion. Within the ∼18,000 families of orthologous genes, we found ∼2,000 common to all strains. Although recombination rates are much higher than mutation rates, we show, both theoretically and using phylogenetic inference, that this does not obscure the phylogenetic signal, which places the B2 phylogenetic group and one group D strain at the basal position. Based on this phylogeny, we inferred past evolutionary events of gain and loss of genes, identifying functional classes under opposite selection pressures. We found an important adaptive role for metabolism diversification within group B2 and Shigella strains, but identified few or no extraintestinal virulence-specific genes, which could render difficult the development of a vaccine against extraintestinal infections. Genome flux in E. coli is confined to a small number of conserved positions in the chromosome, which most often are not associated with integrases or tRNA genes. Core genes flanking some of these regions show higher rates of recombination, suggesting that a gene, once acquired by a strain, spreads within the species by homologous recombination at the flanking genes. Finally, the genome's long-scale structure of recombination indicates lower recombination rates, but not higher mutation rates, at the terminus of replication. The ensuing effect of background selection and biased gene conversion may thus explain why this region is A+T-rich and shows high sequence divergence but low sequence polymorphism. Overall, despite a very high gene flow, genes co-exist in an organised genome