Hyperbolicity of singular spaces

We study the hyperbolicity of singular quotients of bounded symmetric domains. We give effective criteria for such quotients to satisfy Green-Griffiths-Lang's conjectures in both analytic and algebraic settings. As an application, we show that Hilbert modular varieties, except for a few possible exceptions, satisfy all expected conjectures.Comment: Main results extended to arbitrary quotient singularities and all bounded symmetric domain

Radiative Thermal Rectification between SiC and SiO2

By means of fluctuationnal electrodynamics, we calculate radiative heat flux between two pla-nar materials respectively made of SiC and SiO2. More specifically, we focus on a first (direct) situation where one of the two materials (for example SiC) is at ambient temperature whereas the second material is at a higher one, then we study a second (reverse) situation where the material temperatures are inverted. When the two fluxes corresponding to the two situations are different, the materials are said to exhibit a thermal rectification, a property with potential applications in thermal regulation. Rectification variations with temperature and separation distance are here reported. Calculations are performed using material optical data experimentally determined by Fourier transform emission spectrometry of heated materials between ambient temperature (around 300 K) and 1480 K. It is shown that rectification is much more important in the near-field domain, i.e. at separation distances smaller than the thermal wavelength. In addition, we see that the larger is the temperature difference, the larger is rectification. Large rectification is finally interpreted due to a weakening of the SiC surface polariton when temperature increases, a weakening which affects much less SiO2 resonances

Skew products, quantitative recurrence, shrinking targets and decay of correlations

We consider toral extensions of hyperbolic dynamical systems. We prove that its quantitative recurrence (also with respect to given observables) and hitting time scale behavior depend on the arithmetical properties of the extension. By this we show that those systems have a polynomial decay of correlations with respect to $C^{r}$ observables, and give estimations for its exponent, which depend on $r$ and on the arithmetical properties of the system. We also show examples of systems of this kind having not the shrinking target property, and having a trivial limit distribution of return time statistics

Modelling of the radiative properties of an opaque porous ceramic layer

Solid Oxide Fuel Cells (SOFCs) operate at temperatures above 1,100 K where radiation effects can be significant. Therefore, an accurate thermal model of an SOFC requires the inclusion of the contribution of thermal radiation. This implies that the thermal radiative properties of the oxide ceramics used in the design of SOFCs must be known. However, little information can be found in the literature concerning their operating temperatures. On the other hand, several types of ceramics with different chemical compositions and microstructures for designing efficient cells are now being tested. This is a situation where the use of a numerical tool making possible the prediction of the thermal radiative properties of SOFC materials, whatever their chemical composition and microstructure are, may be a decisive help. Using this method, first attempts to predict the radiative properties of a lanthanum nickelate porous layer deposited onto an yttria stabilized zirconium substrate can be reported

Relations parents immigrants-écoles dans l’espace montréalais : au-delà des tensions, la rencontre des rêves

La récente controverse autour des accommodements raisonnables met en relief les enjeux identitaires, dans les écoles qui desservent une clientèle de plus en plus pluriethnique. La création des liens parents immigrants-écoles, essentielle et souhaitée, est modulée par des tensions sociales et politiques et représente un défi parfois difficile à relever. Cet article rapporte les résultats de groupes de discussion avec des parents et des enseignants dans deux écoles montréalaises, dans le but de documenter la relation parents immigrants-écoles. S’inspirant des recommandations formulées par les participants, la discussion offre des pistes pour repenser les échanges entre les parents et la communauté afin de générer des domaines de compréhension partagée.The recent controversy over reasonable accommodation has underscored identity issues in the increasingly multiethnic student population of Montreal schools. While the establishment of good relations between immigrant parents and schools is essential and to be encouraged, it is subject to sociopolitical tensions and represents a sometimes daunting challenge. In this article, the results of parent-teacher focus groups that were organized in two Montreal schools to collect data on these relations are presented. Building on recommendations made by parents and teachers, the article suggests avenues for rethinking interaction between parents and the community as a way of laying the groundwork for mutual understanding.La reciente controversia alrededor de los acomodamientos razonables hace resaltar los retos identitarios en las escuelas que atienden a una clientela cada vez más multiétnica. La creación de los vínculos padres inmigrantes - escuelas, esencial y deseada, está modulada por tensiones sociales y políticas y representa un desafío a veces difícil de enfrentar. Este artículo presenta los resultados de unos grupos de discusión con padres y maestros en dos escuelas de Montreal, con el propósito de documentar la relación padres inmigrantes - escuelas. Inspirándose de las recomendaciones formuladas por los participantes, la discusión ofrece pistas para repensar los intercambios entre los padres y la comunicad, con la finalidad de generar dominios de comprensión compartida

On the value of the Kullback-Leibler divergence for cost-effective spectral imaging of plants by optimal selection of wavebands

The practical value of a criterion based on statistical information theory is demonstrated for the selection of optimal wavelength and bandwidth of low-cost lighting systems in plant imaging applications. Kullback–Leibler divergence is applied to the problem of spectral band reduction from hyperspectral imaging. The results are illustrated on various plant imaging problems and show similar results to the one obtained with state-of-the-art criteria. A specific interest of the proposed approach is to offer the possibility to integrate technological constraints in the optimization of the spectral bands selected