796 research outputs found
Litterature et harmonie du monde au XVIe siecle
La renaissance frangaise est partagee entre les ideaux humanistes de paix grace a la culture, et le spectacle des conflits qui montrent l’echec de la parole devant la barbarie. Pour comprendre la valeur que les hommes de ce temps pretaient a la litterature, il faut entrer dans les resonances metaphysiques des notions de musique et d’harmonie du monde, mais aussi voir pourquoi a ce moment de l’histoire que l’on promeut la cohesion et de l’unite = Исследуется литература французского Ренессанса, дающая представление о культуре и гуманистических идеалах этого периода мирового развити
L’histoire des mentalites en litterature: l’imaginaire de la creation au XVIe siecle
De meme qu’il existe un courant d’etudes des mentalites dans les disciplines historiques, il s’agit d’affiner une methode de critique litteraire qui s’appuie sur l’analyse prealable des mentalites esthetiques, pour cerner les conditions de creation des muvres, leur systeme exegetique et la representation que l’on se faisait de la valeur des muvres et de leur fonction. Nous voudrions proposer ici, apres quelques remarques de methode, des pistes pour mieux apprehender l ’imaginaire de la creation litteraire au XVIe siecl
Internal friction peaks observed in explosively deformed polycrystalline Mo, Nb, and Cu
Explosive deformation (50 kbar range) induced, in Cu, Mo and Nb, internal friction peaks identical to those observed after large normal deformation. The variation of the peaks with pressure for Mo and Nb lead to an explanation of these processes in terms of double kink generation in screw and edge dislocations
Development of lanthanum nickelate as a cathode for use in intermediate temperature solid oxide fuel cells
The performance of lanthanum nickelate, La2NiO4+δ (LNO), as a cathode in IT-SOFCs with the electrolyte cerium gadolinium oxide, Ce0.9Gd0.1O2−δ (CGO), has been investigated by AC impedance spectroscopy of symmetrical cells. A significant reduction in the area specific resistance (ASR) has been achieved with a layered cathode structure consisting of a thin compact LNO layer between the dense electrolyte and porous electrode. This decrease in ASR is believed to be a result of contact at the electrolyte/cathode boundary enhancing the oxygen ion transfer to the electrolyte. An ASR of 1.0 Ω cm2 at 700 °C was measured in a symmetrical cell with this layered structure, compared to an ASR of 7.4 Ω cm2 in a cell without the compact layer. In addition, further improvements were observed by enhancing the cell current collection and it is anticipated that a symmetrical cell consisting of a layered structure with adequate current collection would lower these ASR values further
Translating the Gospels - A Discussion Between Dr. E. V. Rieu and the Rev. J.B. Phillips
Translating the Gospels - A Discussion Between Dr. E. V. Rieu and the Rev. J.B. Phillip
Investigation of Graded La2NiO4+ Cathodes to Improve SOFC Electrochemical Performance
Mixed ionic and electronic conducting MIEC oxides are promising materials for use as cathodes in solid oxide fuel cells SOFCs due to their enhanced electrocatalytic activity compared with electronic conducting oxides. In this paper, the MIEC oxide La2NiO4+ was prepared by the sol-gel route. Graded cathodes were deposited onto yttria-stabilized zirconia YSZ pellets by dip-coating, and electrochemical impedance spectroscopy studies were performed to characterize the symmetrical cell performance. By adapting the slurries, cathode layers with different porosities and thicknesses were obtained. A ceria gadolinium oxide CGO barrier layer was introduced, avoiding insulating La2Zr2O7 phase formation and thus reducing resistance polarization of the cathode. A systematic correlation between microstructure, composition, and electrochemical performance of these cathodes has been performed. An improvement of the electrochemical performance has been demonstrated, and a reduction in the area specific resistance ASR by a factor of 4.5 has been achieved with a compact interlayer of La2NiO4+ between the dense electrolyte and the porous La2NiO4+ cathode layer. The lowest observed ASR of 0.11 cm2 at 800°C was obtained from a symmetrical cell composed of a YSZ electrolyte, a CGO interlayer, an intermediate compact La2NiO4+ layer, a porous La2NiO4+ electrode layer, and a current collection layer of platinum paste
Ségrégation intergranulaire des éléments de la famille du soufre dans le fer pur
Les mécanismes de ségrégation intergranulaire des éléments soufre, sélénium et tellure ont été étudiés en utilisant d'une part nos propres mesures de ségrégation obtenues par rétrodiffusion élastique d'ions accélérés dans le cas des éléments sélénium et tellure, d'autre part quelques résultats de la littérature obtenus par spectroscopie Auger dans le cas des ségrégations de soufre. L'ensemble des résultats montre que la ségrégation intergranulaire des trois métalloïdes obéit aux mêmes lois. Il s'agit essentiellement d'une ségrégation d'équilibre, réversible et activée thermiquement qui n'est pas modifiée par la présence de carbone ségrégé aux joints de grains. Une équation générale est proposée. Elle permet de décrire nos résultats ainsi que certains résultats de la littérature
Multi-level interactions between heat shock factors, heat shock proteins, and the redox system regulate acclimation to heat
Citation: Driedonks, N., Xu, J., Peters, J. L., Park, S., & Rieu, I. (2015). Multi-level interactions between heat shock factors, heat shock proteins, and the redox system regulate acclimation to heat. Frontiers in Plant Science, 6(NOVEMBER). doi:10.3389/fpls.2015.00999High temperature has become a global concern because it seriously affects the growth and reproduction of plants. Exposure of plant cells to high temperatures result in cellular damage and can even lead to cell death. Part of the damage can be ascribed to the action of reactive oxygen species (ROS), which accumulate during abiotic stresses such as heat stress. ROS are toxic and can modify other biomacromolecules including membrane lipids, DNA, and proteins. In order to protect the cells, ROS scavenging is essential. In contrast with their inherent harms, ROS also function as signaling molecules, inducing stress tolerance mechanisms. This review examines the evidence for crosstalk between the classical heat stress response, which consists of heat shock factors (HSFs) and heat shock proteins (HSPs), with the ROS network at multiple levels in the heat response process. Heat stimulates HSF activity directly, but also indirectly via ROS. HSFs in turn stimulate the expression of HSP chaperones and also affect ROS scavenger gene expression. In the short term, HSFs repress expression of superoxide dismutase scavenger genes via induction of miRNA398, while they also activate scavenger gene expression and stabilize scavenger protein activity via HSP induction. We propose that these contrasting effects allow for the boosting of the heat stress response at the very onset of the stress, while preventing subsequent oxidative damage. The described model on HSFs, HSPs, ROS, and ROS scavenger interactions seems applicable to responses to stresses other than heat and may explain the phenomenon of crossacclimation. © 2015 Driedonks, Xu, Peters, Park and Rieu
Continuous macroscopic limit of a discrete stochastic model for interaction of living cells
In the development of multiscale biological models it is crucial to establish
a connection between discrete microscopic or mesoscopic stochastic models and
macroscopic continuous descriptions based on cellular density. In this paper a
continuous limit of a two-dimensional Cellular Potts Model (CPM) with excluded
volume is derived, describing cells moving in a medium and reacting to each
other through both direct contact and long range chemotaxis. The continuous
macroscopic model is obtained as a Fokker-Planck equation describing evolution
of the cell probability density function. All coefficients of the general
macroscopic model are derived from parameters of the CPM and a very good
agreement is demonstrated between CPM Monte Carlo simulations and numerical
solution of the macroscopic model. It is also shown that in the absence of
contact cell-cell interactions, the obtained model reduces to the classical
macroscopic Keller-Segel model. General multiscale approach is demonstrated by
simulating spongy bone formation from loosely packed mesenchyme via the
intramembranous route suggesting that self-organizing physical mechanisms can
account for this developmental process.Comment: 4 pages, 3 figure
The Non-thermal Radio Jet Toward the NGC 2264 Star Formation Region
We report sensitive VLA 3.6 cm radio observations toward the head of the Cone
nebula in NGC 2264, made in 2006. The purpose of these observations was to
study a non-thermal radio jet recently discovered, that appears to emanate from
the head of the Cone nebula. The jet is highly polarized, with well-defined
knots, and one-sided. The comparison of our images with 1995 archive data
indicates no evidence of proper motions nor polarization changes. We find
reliable flux density variations in only one knot, which we tentatively
identify as the core of a quasar or radio galaxy. An extragalactic location
seems to be the best explanation for this jet.Comment: 12 pages, 5 figure
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