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Le temps des SIC
No full textLe corpus traité est disponible sur 10.5281/zenodo.1000780International audienceTo understand the notions of temporality in Information and Communication Sciences (ICS), we choose to analyze lexicon of researchers. Our study is based on texts freely submitted by authors on platform HAL / @ sic. Text mining is carried out by several lexicometric analysis, with two aims : to understand the concepts related to “time” in ICS' research and identify changes over time in ICS' researchers’ fields and questions.Pour rendre compte du temps des Sciences de l'Information et de la Communication (SIC), nous avons choisi d'analyser le lexique des chercheurs. Notre étude s'appuie sur les textes librement déposés par les auteurs sur la plateforme HAL/@sic. La fouille de texte s'effectue par une série d'analyses lexicométriques afin de répondre à deux objectifs : appréhender les notions liées au temps dans les recherches en SIC, d'une part, d'autre part rendre compte de l'évolution dans le temps des champs et questions de recherche en SIC
Ce/Al correlation in aluminosilicate glasses and optical silica fiber preforms
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Convergence analysis of upwind type schemes for the aggregation equation with pointy potential
No full textA numerical analysis of upwind type schemes for the nonlinear nonlocal aggregation equation is provided. In this approach, the aggregation equation is interpreted as a conservative transport equation driven by a nonlocal nonlinear velocity field with low regularity. In particular, we allow the interacting potential to be pointy, in which case the velocity field may have discontinuities. Based on recent results of existence and uniqueness of a Filippov flow for this type of equations, we study an upwind finite volume numerical scheme and we prove that it is convergent at order 1/2 in Wasserstein distance. This result is illustrated by numerical simulations, which show the optimality of the order of convergence
Groupes projectifs et arrangements de droites
No full textThe objective of this thesis is to investigate various questions about projective groups and line arrangements in the projective plane. A projective group is a group which is isomorphic to the fundamental group of a smooth complex projective variety. To study projective groups, sophisticated techniques in algebraic topology and algebraic geometry have been developed in the passed decades, for instance, the theory of cohomology jump loci, together with Hodge theory, has been proven a powerful tool. Line arrangements in the projective plane are of special interest in the study of projective groups. Indeed, there are many open questions related to projective groups, and the theory of hyperplane arrangements, and in particular that of line arrangements, which is quite an active area of research, may provide insights for these problems. Furthermore, problems concerning the fundamental groups of the complements of hyperplane arrangements can be reduced to the case of line arrangements, due to the celebrated Zariski theorem of Lefschetz type. Very often, in the study of projective groups or quasi-projective groups, one usually considers line arrangements first to get some intuitive ideas. In this thesis, we also prove some theorems that are of independent interest and can be used elsewhere, for instance, we prove properties concerning morphisms from products of projective spaces in Chapter 4, we show that some morphisms have generic connected fibers in Chapter 5 and we give criteria for a projective surface to be of general type in Chapter 7.Le but de cette thèse est de considérer différentes questions sur les groupes projectifs et sur les arrangements de droites dans le plan projectif. Un groupe projectif est un groupe qui est isomorphe au groupe fondamental d'une variété projective lisse complexe. Pour étudier les groupes projectifs, des techniques sophistiquées de topologie algébrique et de géométrie algébrique ont été développées pendant les dernières décennies, par exemple la théorie des variétés caractéristiques combinée avec la théorie de Hodge s'est montrée être un outil puissant. Les arrangements de droites dans le plan projectif ont une place centrale dans l'étude des groupes projectifs. En effet, il y a beaucoup de questions ouvertes sur les groupes projectifs, et la théorie des arrangements d'hyperplans, en particulier celle des arrangements de droites, qui est un domaine très actif de recherche, peut suggérer des solutions à ces problèmes. En outre, les problèmes sur les groupes fondamentaux de complémentaires des arrangements d'hyperplans peuvent être réduits au cas des arrangements de droites, en utilisant le bien connu Théorème de Zariski du type de Lefschetz. Assez souvent, pour étudier les groupes projectifs ou quasi-projectifs, on considère d'abord les arrangements de droites pour obtenir des idées intuitives. Dans cette thèse nous obtenons aussi des résultats d'intérêts indépendants, par exemple sur les morphismes définis sur un produit d'espaces projectifs dans le Chapitre 4, sur la fibre générale de certains morphismes dans le Chapitre 5 et les critères sur les surfaces de type générales au Chapitre 7
Synthesis and anti-cancer activities of new sulfonamides 4-substituted-triazolyl nucleosides
No full textInternational audienceNucleoside analogues are among the most known drugs commonly used in antiviral and anticancer chemotherapies. Among them, those featuring a five-membered ring nucleobase are of utmost interest such as the anti-cancer agent AICAR or the anti-viral drug ribavirin. Despite its low activity in vitro in different cell lines, AICAR is under clinical development for several pathologies, thanks to its original mode of action. Indeed, AICAR induced autophagy cell death and is able, following this mechanism, to circumvent resistance to apoptotic drugs including kinase inhibitors currently on the market. To improve the activity of AICAR, we report herein an efficient synthesis of new series of sulfonamide-4-substituted-1,2,3-triazolyl nucleosides using a Cu-catalyzed 1,3-dipolar cycloaddition. All these molecules have been fully characterized and evaluated against two aggressive tumor cell lines, RCC4 and MDA-MB-231. Among them, nucleoside analogue 5i belonging to the ribose series was found to be 19 to 66-fold more active than AICAR. Western blot analyses on RCC4 cells showed that 5i displayed an interesting mode of action by inducing both apoptosis and autophagy cell death, making therefore this class of molecules highly promising for further hit-to-lead optimization
Web Audio Guitar Tube Amplifier vs Native Simulations
No full textInternational audienceWe propose to present a tube guitar amplifier simulation we’ve been designing using the Web Audio API with the aim to faithfully reproduce the main parts of the Marshall JCM 800 amplifier schematics. Each stage of the real amp has been recreated (preamp, tone stack, reverb, power amp and speaker simulation). We’ve also added an extra multiband EQ. This “classic rock” amp simulation we’ve been building has been used in real gigs and can be favorably compared with some native amp simulation both in terms of latency, sound quality, dynamics and comfort of the guitar play. The amp is open source and can be tested online, even without a real guitar plugged-in. It comes with an audio player, dry guitar samples and a wave generator that can be used as inputs. Figure 1 shows the current GUI, with some optional frequency analyzers and oscilloscopes that we’ve been using to probe the signal at different stages of the simulation. One purpose was to evaluate the limits of the Web Audio API and see if it was possible to design a web-based guitar amp simulator that could compete with native simulations
Influence of organically modified montmorillonite and sepiolite clays on the physical properties of bio-based poly(ethylene 2,5-furandicarboxylate)
No full textInternational audienceNanocomposites based on bio-based Poly(ethylene 2,5-furandicarboxylate), PEF, and different nanoclays (either sepiolite or montmorillonite, both organically modified) were prepared by melt extrusion and compression molding. Firstly, the impact of processing at high temperatures on PEF molecular weight is evaluated and correlated to the presence of the different clays used in the nanocomposite. Then, the melt- and the solid-state properties of PEF nanocomposites are characterized by using different analytical techniques (rheological tests, TGA, DSC, DMA). It is shown how some clay features such as the clay organo-modification may affect the polymer behavior
Pedestrian motion modeled by FP-constrained Nash games
No full textInternational audienceA new approach to modeling pedestrian's avoidance dynamics based on a Fokker-Planck Nash game framework is presented. In this framework, two interacting pedestrian are considered, whose motion variability is modeled through the corresponding probability density functions (PDFs) governed by Fokker-Planck equations. Based on these equations, a Nash differential game is formulated where the game strategies represent controls aiming at avoidance by minimizing appropriate collision cost functionals. Existence of Nash equlibria solution is proved and characterized as solution to an optimal control problem that is solved numerically. Results of numerical experiments are presented that successfully compare the computed Nash equilibria to output of real experiments (conducted with humans) for 4 test cases
Exploring the potential of a structural alphabet-based tool for mining multiple target conformations and target flexibility insight
No full textInternational audienceProtein flexibility is often implied in binding with different partners and is essential for protein function. The growing number of macromolecular structures in the Protein Data Bank entries and their redundancy has become a major source of structural knowledge of the protein universe. The analysis of structural variability through available redundant structures of a target , called multiple target conformations (MTC), obtained using experimental or modeling methods and under different biological conditions or different sources is one way to explore protein flexibility. This analysis is essential to improve the understanding of various mechanisms associated with protein target function and flexibility. In this study, we explored structural variability of three biological targets by analyzing different MTC sets associated with these targets. To facilitate the study of these MTC sets, we have developed an efficient tool, SA-conf, dedicated to capturing and linking the amino acid and local structure variability and analyzing the target structural variability space. The advantage of SA-conf is that it could be applied to divers sets composed of MTCs available in the PDB obtained using NMR and crystallography or homology models. This tool could also be applied to analyze MTC sets obtained by dynamics approaches. Our results showed that SA-conf tool is effective to quantify the structural variability of a MTC set and to localize the structural variable positions and regions of the target. By selecting adapted MTC subsets and comparing their variability detected by SA-conf, we highlighted different sources of target flexibility such as induced by binding partner, by mutation and intrinsic flexibility. Our results support the interest to mine available structures associated with a target using to offer valuable insight into target flexibility and interaction mechanisms
Pioneering Cities of Mining: Comparison of the Eastern Venezuela and Eastern Siberia
No full textInternational audienceThe development of the mine, gas and oil extraction in the Eastern Venezuela (Oriente and Guayana regions) and the Far Eastern (Oriental Siberia) is characterized by the emergence of pioneer small and medium cities during the last fifty years and an emerging process of metropolisation since 2000 (Yakutsk, Ciudad Guayana). In Eastern Venezuela, the urbanization is partially planned, generally “spontaneous”. In Yakutia, dynamics of urbanization is planned. In the both cases, urban dynamics is driven by the exploitation of the natural resources and the immigration. With the collapse of the Soviet Union, some mining towns disappeared in the 1990 and 2000. Since the beginning of the 2010’s mining urban regions are under a double process of territorial integration with Russian Europe and Asia. In Venezuela, small and medium sized cities are growing with the emergence of new mining territories and the exploitation of the Orinoco Belt (extra heavy oil). This article analyses the main territorial dynamics of these small and medium sized cities