The Autonomous University of Aguascalientes is a Mexican public university based in the city of Aguascalientes, Aguascalientes, and has several campuses that are located across the state.Its library is named after poet and university president Desiderio Macías Silva, and holds over 183,063 volumes. Wikipedia.
Macias-Diaz J.E.,Autonomous University of Aguascalientes
Wave Motion | Year: 2011
The nonlinear processes of supratransmission and infratransmission are employed here in order to show numerically that binary information may be transmitted into (2. +. 1)-dimensional, continuous Frenkel-Kontorova media spatially defined on a square, by perturbing harmonically two adjacent boundaries by means of Neumann conditions. The presence of these nonlinear phenomena is established numerically through a computational method that preserves the positivity of the energy operators, and that consistently approximates the solution of the model, the local energy density, the total energy and its dissipation; the existence of a region of bistability where two regimes coexist (conducting and insulating) is established as a corollary. The transmission of binary information is accomplished by fixing a frequency in the forbidden band-gap of the system, and modulating the amplitude of the signals as the sum of a seed (whose amplitude oscillates sinusoidally between the supratransmission and infratransmission thresholds) and small, positive, constant perturbations associated to nonzero bits. Our simulations show that a reliable transmission of information is indeed feasible. © 2010 Elsevier B.V.
MacIas-Diaz J.E.,Autonomous University of Aguascalientes
Computer Physics Communications | Year: 2011
Departing from a finite-difference scheme to approximate solutions of a nonlinear, hyperbolic partial differential equation which generalizes the Burgers-Huxley equation from fluid dynamics, we investigate conditions on the model coefficients and the computational parameters under which positive and bounded initial data evolve into positive and bounded new approximations. The model under investigation includes nonlinear coefficients of damping and advection, and the reaction term extends the reaction law of the classical Fisher-Kolmogorov-Petrovsky-Piscounov equation. The method can be expressed in vector form in terms of a multiplicative matrix which, under certain parametric conditions, becomes an M-matrix. Using the fact that every M-matrix is non-singular and that the entries of its inverse are positive, real numbers, we establish sufficient conditions under which the method provides new, positive and bounded approximations from previous, positive and bounded data and boundary conditions. The numerical results confirm the fact that the conditions derived here are sufficient for the positivity and the boundedness of the approximations; moreover, computational experiments evidence the fact that the method still preserves these properties for values of the model and the numerical parameters outside of the analytic regions of positivity and boundedness. We point out that our simulations show a good agreement between the numerical approximations computed through our method and the corresponding, analytical solutions. © 2011 Elsevier B.V.
Campos-Esparza M.R.,Autonomous University of Aguascalientes
Central nervous system agents in medicinal chemistry | Year: 2010
Polyphenols are the most abundant antioxidants in diet. These can be found in fruits, vegetables, beverages (tea, wine, juices, etc.), plants and some herbs. These compounds are capable of protecting neuronal cells in different in vivo and in vitro models through diverse intracellular targets. The focus of this review is aimed at presenting the role of some polyphenols on the molecular mechanism involve in neuroprotection through different biological processes like oxidative stress, excitotoxicity, apoptotic neuronal death, regulation of the kinase signal cascade and modulation of Ubiquitin-Proteasome pathway. The study of the molecular mechanisms involved in neuroprotection and the molecular targets of natural polyphenols are important in the discovery of a valuable tool for new and more advanced therapy in neurodegenerative diseases.
Macias-Diaz J.E.,Autonomous University of Aguascalientes
International Journal of Modern Physics C | Year: 2011
In the present manuscript, we introduce a finite-difference scheme to approximate solutions of the two-dimensional version of Fisher's equation from population dynamics, which is a model for which the existence of traveling-wave fronts bounded within (0,1) is a well-known fact. The method presented here is a nonstandard technique which, in the linear regime, approximates the solutions of the original model with a consistency of second order in space and first order in time. The theory of M-matrices is employed here in order to elucidate conditions under which the method is able to preserve the positivity and the boundedness of solutions. In fact, our main result establishes relatively flexible conditions under which the preservation of the positivity and the boundedness of new approximations is guaranteed. Some simulations of the propagation of a traveling-wave solution confirm the analytical results derived in this work; moreover, the experiments evince a good agreement between the numerical result and the analytical solutions. © 2011 World Scientific Publishing Company.
Munoz Zavala A.E.,Autonomous University of Aguascalientes
Advances in Intelligent Systems and Computing | Year: 2013
A comparative study is performed to reveal the convergence characteristics and the robustness of three local neighborhoods in the particle swarm optimization algorithm (PSO): ring, Von Neumann and singly-linked ring. In the PSO algorithm, a neighborhood enables different communication paths among its members, and therefore, the way the swarm searches the landscape. Since the neighborhood structure changes the flying pattern of the swarm, convergence and diversity differ from structure to structure. A set of controled experiments is developed to observe the transmission behavior (convergency) of every structure. The comparison results illustrate similarities and differences in the three topologies. A brief discussion is provided to further reveal the reasons which may account for the difference of the three neighborhoods. © Springer-Verlag Berlin Heidelberg 2013.