9,507 research outputs found

    A Fundamental Theorem for submanifolds of multiproducts of real space forms

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    We prove a Bonnet theorem for isometric immersions of submanifolds into the products of an arbitrary number of simply connected real space forms. Then, we prove the existence of associated families of minimal surfaces in such products. Finally, in the case of S2×S2\mathbb{S}^2\times\mathbb{S}^2, we give a complex version of the main theorem in terms of the two canonical complex structures of S2×S2\mathbb{S}^2\times\mathbb{S}^2

    An overview of the effect of probiotics and exercise on mood and associated health conditions

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    The present paper provides a review of the current knowledge relating to the health benefits of probiotics, specially focused on the effects they may have together with physical exercise on mood disorders and related chronic medical conditions. With both these conditions being a substantial contributor to the global disease burden any alternative therapy must be considered. Probiotics influence the gut microbiota through a complex network of events which can influence mechanisms leading to development of mood disorders such as depression and anxiety. Similarly, through a complex interaction between psychological and neurobiological mechanisms, exercise has been found to play a key role in mood enhancement

    Minimizing makespan in flowshop with time lags

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    We consider the problem of minimizing the makespan in a flowshop involving maximal and minimal time lags. Time lag constraints generalize the classical precedence constraints between operations. We assume that such constraints are only defined between operations of the same job. We propose a solution method and present several extensions.Comment: 2 pages. Also available at http://hal.inria.fr/inria-0000014

    An ab-initio evaluation of the local effective interactions in the NaxCoO2\rm Na_{x} Co O_2 familly

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    We used quantum chemical ab initio methods to determine the effective parameters of Hubbard and t−Jt-J models for the NaxCoO2\rm Na_{x}CoO_2 compounds (x=0 and 0.5). As for the superconducting compound we found the a1ga_{1g} cobalt orbitals above the eg′e_g^\prime ones by a few hundreds of meV due to the eg′e_g^\prime--ege_g hybridization of the cobalt 3d3d orbitals. The correlation strength was found to increase with the sodium content xx while the in-plane AFM coupling decreases. The less correlated system was found to be the pure CoO2CoO_2, however it is still strongly correlated and very close to the Mott transition. Indeed we found U/t∼15U/t\sim 15, which is the critical value for the Mott transition in a triangular lattice. Finally, one finds the magnetic exchanges in the CoO2\rm CoO_2 layers, strongly dependant of the weak local structural distortions

    First principles calculation of the phonons modes in the hexagonal YMnO3\rm YMnO_3 ferroelectric and paraelectric phases

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    The lattice dynamics of the YMnO3\rm YMnO_3 magneto-electric compound has been investigated using density functional calculations, both in the ferroelectric and the paraelectric phases. The coherence between the computed and experimental data is very good in the low temperature phase. Using group theory, modes continuity and our calculations we were able to show that the phonons modes observed by Raman scattering at 1200K are only compatible with the ferroelectric P63cmP6_{3} cm space group, thus supporting the idea of a ferroelectric to paraelectric phase transition at higher temperature. Finally we proposed a candidate for the phonon part of the observed electro-magnon. This mode, inactive both in Raman scattering and in Infra-Red, was shown to strongly couple to the Mn-Mn magnetic interactions

    Electronic structure of the Ca3Co4O9\rm Ca_3Co_4O_9 compound from ab initio local interactions

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    We used fully correlated ab initio calculations to determine the effective parameters of Hubbard and t - J models for the thermoelectric misfit compound Ca3Co4O9\rm Ca_3Co_4O_9. As for the NaxCoO2\rm Na_xCoO_2 family the Fermi level orbitals are the a1ga_{1g} orbitals of the cobalt atoms ; the eg′e'_g being always lower in energy by more than 240\,meV. The electron correlation is found very large U/t∼26U/t\sim 26 as well as the parameters fluctuations as a function of the structural modulation. The main consequences are a partial a1ga_{1g} electrons localization and a fluctuation of the in-plane magnetic exchange from AFM to FM. The behavior of the Seebeck coefficient as a function of temperature is discussed in view of the ab initio results, as well as the 496\,K phase transition

    Multidimensional Urban Segregation - Toward A Neural Network Measure

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    We introduce a multidimensional, neural-network approach to reveal and measure urban segregation phenomena, based on the Self-Organizing Map algorithm (SOM). The multidimensionality of SOM allows one to apprehend a large number of variables simultaneously, defined on census or other types of statistical blocks, and to perform clustering along them. Levels of segregation are then measured through correlations between distances on the neural network and distances on the actual geographical map. Further, the stochasticity of SOM enables one to quantify levels of heterogeneity across census blocks. We illustrate this new method on data available for the city of Paris.Comment: NCAA S.I. WSOM+ 201

    Huellas de la dictadura en Paraguay: la política cotidiana como forma de resistencia tranquila

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    Metadados do Trabalho de Conclusão de Curso: Huellas de la dictadura en Paraguay: la política cotidiana como forma de resistencia tranquila, pela/o discente: Julien Marie Demelenne sob orientação: Victoria Darling do Centro de Integração e Relações Internacionais, curso de Ciência Política - Sociologia da Universidade Federal da Integração Latino-Americana (UNILA), no Repositório Institucional da UNILA (RI-UNILA).Huellas de la dictadura en Paraguay: la política cotidiana como forma de resistencia tranquil
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