This paper presents a new approach to guaranteed state estimation for non-linear discrete-time systems with a bounded description of noise and parameters. The sets of states that are consistent with the evolution of the system, the measured outputs and bounded noise and parameters are represented by zonotopes. DC programming and intersection operations are used to obtain a tight bound. An example is given to illustrate the proposed algorithm.

Introduction. This article addresses clickbait as a strategy of viral journalism that seeks to lure users into clicking on a link to a page through tactics such as sensationalist stories and eye-catching headlines that work as bait. This research aims to provide a more complete definition of this phenomenon, as well as a characterisation of the variables associated with it. Methods. In its empirical phase, the study resorts to content analysis to check for the presence of clickbait strategies in 2,266 news stories posted on Facebook and Twitter by El País and El Mundo. Results. The research detected a high presence of clickbait content in both newspapers (41.6% on average), as well as the prevalence of techniques such as: incomplete information, pre-eminence of soft news, repetition and serialisation, and use of hyperboles. Discussion. The scarcity of research on clickbait requires the intensification of the analysis of its evolution and the monitoring of its consequences on the quality of the news circulating on social networks.

In the field of energy, hydrogen as an energetic vector is becoming increasingly important. Specifically, fuel cells powered by hydrogen are becoming an alternative in automotive and other fields because of their ability to produce electricity without any pollution. Therefore, at this time there is a very active research field. A fuel cell can be described as a scale down industrial plant that consists of different subsystems whose purpose is to make the stack works properly. Air Cooled Polymer Electrolyte Fuel Cells (AC-PEFC) are receiving special attention due to their potential to integrate the oxidant and cooling subsystems into one, which in term gives the fuel cells their capability to reduce its weight, volume, cost and control complexity. In these fuel cells, the Oxidant/Cooling subsystem is of crucial importance and along with three others (Fuel, Electrical and Control subsystems) make up the Balance of Plant (BoP), which together with the stack comprise the full fuel cell system. The aim of this paper is to present a comprehensive experimental study of an AC-PEFC paying particular attention to the Oxidant/Cooling subsystem configuration. According to the scientific literature, this subsystem has not received the same attention as other subsystems like the Fuel and Control subsystems. However, a suitable design and size is critical for the proper functioning of the stack. The analysis carried out in this paper tries to solve some problems that can appear if the design of the Oxidant/Cooling subsystem has not been optimized. These problems are related to important aspects such as the performance and the efficiency of the whole system and temperature distribution over the stack.

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Se discuten y analizan algunas de los métodos más comunes sobre enseñanza-aprendizaje usados en cursos de electrónica. La discusión se centra en la eficiencia de los métodos para transmitir conceptos a los estudiantes. Se discute sobre las principales ventajas y desventajas de las técnicas audiovisuales (imágenes, fotografías, sonido, videos y animaciones), de las aplicaciones de computación, y de los experimentos de laboratorio. El artículo propone un método que incluye estas tres técnicas y se aplica la propuesta al montaje de un circuito electrónico. Se concluye que con videos y animaciones, además de confeccionar aplicaciones atractivas que motivan al alumno, se pueden mostrar procesos que resultarían imposibles de describir con imágenes estáticas solamente.