Asymptotic Behavior for a Coalescence Problem

Consider spherical particles of volume x having paint on a fraction y of their surface area. The particles are assumed to be homogeneously distributed at each time t, so that one can introduce the density number n (x, y, t). When collision between two particles occurs, the particles will coalesce if and only if they happen to touch each other, at impact, at points which do not belong to the painted portions of their surfaces. Introducing a dynamics for this model, we study the evolution of n (x, y, t) and, in particular, the asymptotic behavior of the mass x n (x, y, t) dx as t → ∞

On the O(1) Solution of Multiple-Scattering Problems

In this paper, we present a multiple-scattering solver for nonconvex geometries such as those obtained as the union of a finite number of convex surfaces. For a prescribed error tolerance, this algorithm exhibits a fixed computational cost for arbitrarily high frequencies. At the core of the method is an extension of the method of stationary phase, together with the use of an ansatz for the unknown density in a combined-field boundary integral formulation

Fractional Driven Damped Oscillator

The resonances associated with a fractional damped oscillator which is driven by an oscillatory external force are studied. It is shown that such resonances can be manipulated by tuning up either the coefficient of the fractional damping or the order of the corresponding fractional derivatives.Comment: 5 pages, 1 Figure. A misprint appearing in Eq. (6) of the published version is amended. Based on the work presented by F. Olivar-Romero in the Quantum Fest 2016: International Conference on Quantum Phenomena, Quantum Control and Quantum Optics, 17-21 October 2016, Mexico City, Mexic

Information and communication in a networked infosphere: a review of concepts and application in social branding

This paper aims at providing a contribution to the comprehensive review of the impact of information and communication, and their supporting technologies, in the current transformation of human life in the infosphere. The paper also offers an ex- ample of the power of new social approaches to the use of information and commu- nication technologies to foster new working models in organizations by presenting the main outcomes of a research project on social branding. A discussion about some trends of the future impact of new information and communication technologies in the infosphere is also included

Nonlinear electrodynamics as a symmetric hyperbolic system

Nonlinear theories generalizing Maxwell's electromagnetism and arising from a Lagrangian formalism have dispersion relations in which propagation planes factor into null planes corresponding to two effective metrics which depend on the point-wise values of the electromagnetic field. These effective Lorentzian metrics share the null (generically two) directions of the electromagnetic field. We show that, the theory is symmetric hyperbolic if and only if the cones these metrics give rise to have a non-empty intersection. Namely that there exist families of symmetrizers in the sense of Geroch which are positive definite for all covectors in the interior of the cones intersection. Thus, for these theories, the initial value problem is well-posed. We illustrate the power of this approach with several nonlinear models of physical interest such as Born-Infeld, Gauss-Bonnet and Euler-Heisenberg

Nuevas tecnologías en el estudio de la razón áurea: enfoque variacional

El taller está orientado a la construcción de diferentes representaciones de la razón áurea y al establecimiento de relaciones entre ellas, además del empleo de diferentes herramientas que ofrece la calculadora TI 92 para construir las fracciones y radicales continuos, los números de Fibonacci, una ecuación de Ramanujan y su relación con la proporción áurea

Conformación de mesas de matemáticas: una experiencia en Antioquia en la formación continua de profesores de matemáticas

En el Departamento de Antioquia, en el 2006 y 2007 se llevó a cabo un diploma de formación de maestros en Competencias Básicas en Matemáticas en convenio entre la Secretaría de Educación para la cultura y la Universidad de Antioquia; en él se capacitaron más de 4.500 maestros y como resultado se conformaron alrededor de 35 mesas municipales de Matemáticas; presento la experiencia de conformación de las mesas y los aportes a los procesos de investigación, cualificación y formación de los docentes