Medios masivos de comunicación, democracia y educación en América Latina : (1973-2013)

El presente trabajo es el resultado de un análisis realizado sobre el poder de los medios masivos de comunicación, su incidencia en el Estado y la política y el rol de la educación en esta díada. Llevar a cabo este proceso fue complejo, pero a la vez interesante y gratificante. Para realizar esta labor, partí desde una mirada abarcativa hasta llegar a los temas particulares. Comencé presentando el papel de los medios de comunicación en la sociedad, el rol que cumplen como informadores y, también como desestabilizadores del orden democrático, en tanto que promotores de los Golpes de Estado en América Latina; en esta instancia, expondré algunos ejemplos de estos últimos 40 años (1973-2013). A continuación, entablaré la relación entre los medios y la educación, principalmente centrándome en el rol de la televisión como agente socializante primario. Asimismo, desarrollaré el tema de la educación como un derecho humano universal, como política de Estado y presentaré la importancia de éstas para la emancipación. Por último, y con una mirada más latinoamericana, expondré las ideas de José Martí, Arturo Roig y Angélica Mendoza, siendo el segundo el autor sobre el que haré foco, retomando sus pensamientos sobre la Filosofía de la Liberación. En las conclusiones, podrán encontrar las reflexiones resultantes de la investigación, así como también una mirada a futuro de Latinoamérica

Robot eye-hand coordination learning by watching human demonstrations: a task function approximation approach

We present a robot eye-hand coordination learning method that can directly learn visual task specification by watching human demonstrations. Task specification is represented as a task function, which is learned using inverse reinforcement learning(IRL) by inferring differential rewards between state changes. The learned task function is then used as continuous feedbacks in an uncalibrated visual servoing(UVS) controller designed for the execution phase. Our proposed method can directly learn from raw videos, which removes the need for hand-engineered task specification. It can also provide task interpretability by directly approximating the task function. Besides, benefiting from the use of a traditional UVS controller, our training process is efficient and the learned policy is independent from a particular robot platform. Various experiments were designed to show that, for a certain DOF task, our method can adapt to task/environment variances in target positions, backgrounds, illuminations, and occlusions without prior retraining.Comment: Accepted in ICRA 201

The Effects of Mind Mapping Activities on Students\u27 Motivation

We examined how students‟ motivation differed when they participated in three different types of mind mapping activities: one activity that was completed individually outside of class time, one that was completed individually in class with the instructor available for help, and one that was completed in class with other students and the instructor available for help. Using the MUSIC Model of Academic Motivation (Jones, 2009) as a framework, we implemented a concurrent mixed methods design using identical samples whereby the quantitative component was dominant over the qualitative component. Participants included 40 undergraduate students enrolled in an educational psychology course at a U.S. university. After each of the mind mapping activities, study participants completed questionnaires that included open- and closed-ended items. Although the three activities had similar effects on students‟ motivation-related beliefs, some differences were documented in their preferences of mind mapping activities. Instructional implications are provided

Unary semigroups with an associate subgroup

A subgroup H of a regular semigroup S is said to be an associate subgroup of S if for every s ∈ S, there is a unique associate of s in H. An idempotent z of S is said to be medial if czc = c, for every c product of idempotents of S. Blyth and Martins established a structure theorem for semigroups with an associate subgroup whose identity is a medial idempotent, in terms of an idempotent generated semigroup, a group and a single homomorphism. Here, we construct a system of axioms which characterize these semigroups in terms of a unary operation satisfying those axioms. As a generalization of this class of semigroups, we characterize regular semigroups S having a subgroup which is a transversal of a congruence on S.Fundação para a Ciência e a Tecnologia (FCT

Ultrarelativistic Bondi--Hoyle Accretion I: Axisymmetry

An ultrarelativistic relativistic study of axisymmetric Bondi--Hoyle accretion onto a moving Kerr black hole is presented. The equations of general relativistic hydrodynamics are solved using high resolution shock capturing methods. In this treatment we consider the ultrarelativistic limit wherein one may neglect the baryon rest mass density. This approximation is valid in the regime where the internal energy of the system dominates over the rest mass energy contribution from the baryons. The parameters of interest in this study are the adiabatic constant $\Gamma$, and the asymptotic speed of the fluid, $v_\infty$. We perform our simulations in three different regimes, subsonic, marginally supersonic, and supersonic, but the primary focus of this study is the parameter regime in which the flow is supersonic, that is when $v_\infty \ge c_{s}^{\infty}$. As expected from previous studies the supersonic regimes reveal interesting dynamics, but even more interesting is the presence of a bow shock in marginally supersonic systems. A range of parameter values were investigated to attempt to capture possible deviations from steady state solutions, none were found. To show the steady state behaviour of each of the flows studied we calculate the energy accretion rates on the Schwarzschild radius. Additionally, we also find that the accretion flows are dependent on the location of the computational boundary, that if the computational boundary is located too close to the black hole the calculated flow profiles are marred with numerical artifacts. This is a problem not found in previous relativistic models for ultrarelativistic hydrodynamic systems.Comment: 16 pages, 15 figures, Typos correcte

Entropic-acoustic instability of shocked Bondi accretion I. What does perturbed Bondi accretion sound like ?

In the radial flow of gas into a black hole (i.e. Bondi accretion), the infall of any entropy or vorticity perturbation produces acoustic waves propagating outward. The dependence of this acoustic flux on the shape of the perturbation is investigated in detail. This is the key process in the mechanism of the entropic-acoustic instability proposed by Foglizzo & Tagger (2000) to explain the instability of Bondi-Hoyle-Lyttleton accretion. These acoustic waves create new entropy and vorticity perturbations when they reach the shock, thus closing the entropic-acoustic cycle. With an adiabatic index 1<gamma<=5/3, the linearized equations describing the perturbations of the Bondi flow are studied analytically and solved numerically. The fundamental frequency of this problem is the cut-off frequency of acoustic refraction, below which ingoing acoustic waves are refracted out. This cut-off is significantly smaller than the Keplerian frequency at the sonic radius and depends on the latitudinal number l of the perturbations. When advected adiabatically inward, entropy and vorticity perturbations trigger acoustic waves propagating outward, with an efficiency which is highest for non radial perturbations l=1. The outgoing acoustic flux produced by the advection of vorticity perturbations is always moderate and peaks at rather low frequency. By contrast, the acoustic flux produced by an entropy wave is highest close to the refraction cut-off. It can be very large if gamma is close to 5/3. These results suggest that the shocked Bondi flow with gamma=5/3 is strongly unstable with respect to the entropic-acoustic mechanism.Comment: 14 pages, 11 figures, accepted for publication in A&