Stochastic mean field formulation of the dynamics of diluted neural networks

We consider pulse-coupled Leaky Integrate-and-Fire neural networks with randomly distributed synaptic couplings. This random dilution induces fluctuations in the evolution of the macroscopic variables and deterministic chaos at the microscopic level. Our main aim is to mimic the effect of the dilution as a noise source acting on the dynamics of a globally coupled non-chaotic system. Indeed, the evolution of a diluted neural network can be well approximated as a fully pulse coupled network, where each neuron is driven by a mean synaptic current plus additive noise. These terms represent the average and the fluctuations of the synaptic currents acting on the single neurons in the diluted system. The main microscopic and macroscopic dynamical features can be retrieved with this stochastic approximation. Furthermore, the microscopic stability of the diluted network can be also reproduced, as demonstrated from the almost coincidence of the measured Lyapunov exponents in the deterministic and stochastic cases for an ample range of system sizes. Our results strongly suggest that the fluctuations in the synaptic currents are responsible for the emergence of chaos in this class of pulse coupled networks.Comment: 12 Pages, 4 Figure

Using GitHub as a Teaching Tool for Programming Courses

GitHub has become the most popular code management platform in the software development industry. It allows developers to manage their software development projects and collaborate with each other. Recently, educators also started using GitHub as a teaching tool for programming courses by hosting code samples and managing student assignments. In this study, we examine how GitHub is being used in academia, and we discuss the motivations and the benefits of using this platform. We also present authors’ experience of using GitHub in programming courses of a software engineering program. We discuss the benefits and challenges of using GitHub and GitHub classroom in the classroom.Cockrell School of Engineerin

Ana Enriqueta Terán: poetisa de la lengua

Este año ha sido esencial en la vida de la escritora Ana Enriqueta Terán, tres libros estupendos suyos han sido publicados en los primeros seis meses. Uno de sonetos con dibujos de ella misma (Otros sonetos de todos mis tiempos. Casa Nacional de las Letras Andrés Bello, Caracas), una novela (Apuntes y congojas de una decadencia narrada en tres muertes. Fundación Editorial El Perro y la Rana, Caracas), y a finales del mes de junio - en el marco del XI Festival Mundial de Poesía de Venezuela -, la prestigiosa Biblioteca Ayacucho ha presentado con el Nº 252 de su Colección Clásica a Piedra de habla, antología poética con prólogo de Patricia Guzmán titulado Ana Enriqueta Terán Voz relampagueante de misterio y belleza, amén de la profusa cronología y concienzuda compilación de las fuentes bibliográficas. También este año, el Museo de Arte Valencia conjuntamente con la Red de Escritores de Venezuela y de un grupo de amigos de la poetisa constituidos como comité preparatorio para la celebración del centenario de la escritora, le rindió un cálido homenaje el domingo 4 de mayo, aniversario noventa y seis (96) de su nacimiento en Valera, estado Trujillo, de la ahora República Bolivariana de Venezuel

Orbital stability of standing waves for the nonlinear Schr\"odinger equation with attractive delta potential and double power repulsive nonlinearity

In this paper, a nonlinear Schr\"odinger equation with an attractive (focusing) delta potential and a repulsive (defocusing) double power nonlinearity in one spatial dimension is considered. It is shown, via explicit construction, that both standing wave and equilibrium solutions do exist for certain parameter regimes. In addition, it is proved that both types of wave solutions are orbitally stable under the flow of the equation by minimizing the charge/energy functional.Comment: 30 pages, 5 figure