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Cordoba, Argentina

The National University of Córdoba , founded in 1613, is the oldest university in Argentina, the fourth oldest in South America and the sixth oldest in Latin America. It is located in Córdoba, the capital of Córdoba Province. Since the early 20th century it has been the second largest university in the country in terms of the number of students, faculty, and academic programs. As the location of the first university founded in the land that is now Argentina, Córdoba has earned the nickname La Docta . Wikipedia.

Suarez Morell E.,Federico Santa Maria Technical University | Foa Torres L.E.F.,National University of Cordoba
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

We report on the effects of laser illumination on the electronic properties of bilayer graphene. By using Floquet theory combined with Green's functions, we unveil the appearance of laser-induced gaps not only at integer multiples of Ω/2 but also at the Dirac point with features which are shown to depend strongly on the laser polarization. Trigonal warping corrections are shown to lead to important corrections for radiation in the terahertz range, reducing the size of the dynamical gaps. Furthermore, our analysis of the topological properties at low energies reveals that, when irradiated with linearly polarized light, ideal bilayer graphene behaves as a trivial insulator, whereas circular polarization leads to a nontrivial insulator per valley. © 2012 American Physical Society. Source

Dotti G.,National University of Cordoba
Physical Review Letters | Year: 2014

A proof is given that the space L of solutions of the linearized vacuum Einstein equation around a Schwarzschild black hole is parametrized by two scalar fields, which are gauge invariant combinations of perturbed algebraic and differential invariants of the Weyl tensor and encode the information on the odd (-) and even (+) sectors L±. These fields measure the distortion of the geometry caused by a generic perturbation and are shown to be pointwise bounded on the outer region r≥2M. © 2014 American Physical Society. Source

Dain S.,National University of Cordoba
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Bekenstein bounds for the entropy of a body imply a universal inequality between size, energy, angular momentum, and charge. We prove this inequality in electromagnetism. We also prove it, for the particular case of zero angular momentum, in general relativity. We further discuss the relation of these inequalities with inequalities between size, angular momentum, and charge recently studied in the literature. © 2015 American Physical Society. Source

Borgnino L.,National University of Cordoba
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2013

Aggregation and disaggregation of particle colloids are one of the most important surface-driven phenomena encountered in the aquatic and terrestrial environments and a key factor controlling a number of important environmental processes. This study investigates the effects of pH, ionic strength, and humic acid concentration on the stability behavior of Fe(III)-montmorillonite, a natural colloid commonly present in natural waters. Time-resolved dynamic light scattering was used to monitor the increase of the aggregate size over time in the aggregation kinetics experiments. Aggregation rate, stability ratio, and CCC (critical coagulation concentration) were calculated to quantify the experimental results, and the DLVO theory was employed to explain the observed behaviors. The effect of humic acid on the colloidal electrosteric stability was also investigated. This study demonstrates that low pH and high ionic strength may destabilize Fe(III)-montmorillonite suspensions, while increasing humic acid concentrations has the opposite effect, stabilizing the suspension at any pH. Comparing the steric and electrostatic effects on the Fe-M stabilization, both have an important influence for all pH levels studied, although steric is more pronounced at low pH and high ionic strength. DLVO energy predictions support the experimental results. The obtained results contribute to the understanding of the behavior of colloidal particles in saline or freshwater natural environments as well as the role of humic acid in the mobility of contaminants associated with natural colloids. © 2013 Elsevier B.V. Source

Sanchez J.,National University of Cordoba | Perronnin F.,Xerox | Mensink T.,University of Amsterdam | Verbeek J.,French Institute for Research in Computer Science and Automation
International Journal of Computer Vision | Year: 2013

A standard approach to describe an image for classification and retrieval purposes is to extract a set of local patch descriptors, encode them into a high dimensional vector and pool them into an image-level signature. The most common patch encoding strategy consists in quantizing the local descriptors into a finite set of prototypical elements. This leads to the popular Bag-of-Visual words representation. In this work, we propose to use the Fisher Kernel framework as an alternative patch encoding strategy: we describe patches by their deviation from an "universal" generative Gaussian mixture model. This representation, which we call Fisher vector has many advantages: it is efficient to compute, it leads to excellent results even with efficient linear classifiers, and it can be compressed with a minimal loss of accuracy using product quantization. We report experimental results on five standard datasets - PASCAL VOC 2007, Caltech 256, SUN 397, ILSVRC 2010 and ImageNet10K - with up to 9M images and 10K classes, showing that the FV framework is a state-of-the-art patch encoding technique. © 2013 Springer Science+Business Media New York. Source

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