The amplitude death phenomenon has been experimentally observed with a pair of thermo-optical oscillators linearly coupled by heat transfer. A parametric analysis has been done and compared with numerical simulations of a time delayed model. The role of the coupling strength is also discussed from experimental and numerical results. [1] are some of the observed behaviors that can be described by phase models considering a weak coupling. On the other hand, effects associated with the amplitude of the different units are expected for strong couplings. One of the most intriguing effects is the so-called amplitude death, dealing with the absence of oscillations for the coupled system while each subsystem oscillates when isolated. Two kinds of amplitude death have been considered. In one of the types the coupling creates a saddle-node pair of fixed points on the limit cycle of the entrained oscillations [5], while the second one is associated with a more common bifurcation-the Hopf bifurcation-in which the oscillation amplitudes are damped out up to reach a steady state [6]. The relevance of the second kind of amplitude death and the important role assumed by the time delay in the coupling of oscillators have been recently noted due to its possible application in physics, chemistry, medicine, and biology [7]. The effect has been predicted to occur for two or more identical or different coupled oscillators [6,[8][9][10], but it has not been experimentally observed until now [7].Here, we present the experimental observation of the amplitude death phenomenon with two optothermal oscillators, located on the same interferometric device and thermally coupled. The relation with the coupling effects on the Hopf bifurcation of the whole system is clearly stated by means of a parametric analysis as a function of the coupling strength and the relative light irradiation of the coupled units. The experimental results are compared with simulations of a time delayed model. The nonlinear system is based on the so-called optothermal bistability with localized absorption (BOITAL) and consists of a Fabry-Pérot cavity where the input mirror is a partially absorbing film, the rear mirror is a high reflection dielectric coating, and the spacer is made of two transparent layers with opposite thermo-optic effects [11]. Such a kind of system presents a multiple steady-state solution associated with the periodic interferometric function and can experience a supercritical Hopf bifurcation due to the competition and time delay between the contributions of the two layers to the light phase shift [11]. With this configuration and increasing the input power, the system destabilizes at the first stable branch yielding a limit cycle, which grows by approaching the neighboring saddle point and a homoclinic connection may occur. After the connection the limit cycle is destroyed and the flow escapes towards an upper node branch where a similar behavior takes place.For a transversally extended optical device, different oscillators separated by a distan...

Jordi Brasó i Rius, J. y Torrebadella Flix, X. (2018) Reflexiones para (re)formular una educación física crítica / Ideas to Re(Formulate) a Critical Physical Education.

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Pere Vergés was one of the most prominent pedagogues in the New School's movement to update education. In Catalonia, together with figures such as Rosa Sensat, Artur Martorell and Alexandre Galí, he contributed to a vision of education centred on sensitivity, the child and their autonomy. The subject of this study is Pere Vergés. It is intended to provide a new vision alongside the existing studies focused on the competitive-sports field. Using a methodology based on the analysis of primary sources, along with a complete set of references that have examined the subject, we conclude that Vergés showed a distinctive and unique character in his pedagogy. Contrary to the postulates of non-competition in the New School movements, yet while maintaining this idea of renewal, he included educational competition as a singular element.

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