Hydrogen bonds are never of an “anti-electrostatic” nature : a brief tour of a misleading nomenclature

This work was carried out with financial support from the Ministerio de Ciencia, Innovación y Universidades (projects PID2021-125207NB-C31 and PID2021-125207NB-C32).A large amount of scientific works have contributed through the years to rigorously reflect the different forces leading to the formation of hydrogen bonds, the electrostatic and polarization ones being the most important among them. However, we have witnessed lately with the emergence of a new terminology, anti-electrostatic hydrogen bonds (AEHBs), that seems to contradict this reality. This nomenclature is used in the literature to describe hydrogen bonds between equally charged systems to justify the existence of these species, despite numerous proofs showing that AEHBs are, as any other hydrogen bond between neutral species, mostly due to electrostatic forces. In this Viewpoint, we summarize the state of the art regarding this issue, try to explain why this terminology is very misleading, and strongly recommend avoiding its use based on the hydrogen bond physical grounds.Peer reviewe

Cuatro décadas del sistema electoral español, 1977-2016

The electoral system for the Spanish Congress of Deputies has celebrated four decades. Created in 1977, constitutionalized in 1978, and institutionalized in 1985, it has been used in thirteen general elections without undergoing any reform process. In this article, we assess the Spanish electoral system, including the recent 2015 and 2016 elections. Thereby, it addresses its choice, its constitutive elements, its main effects in both the inter-party and intra-party dimensions, some of the many proposals that have been suggested to reform it, and some controversial decisions taken by the Constitutional Court.El sistema electoral del Congreso de los Diputados ha cumplido cuatro décadas de funcionamiento. Creado en 1977, constitucionalizado en 1978 e institucionalizado en 1985, ha sido empleado en trece procesos electorales sin experimentar reforma alguna. En este artículo ofrecemos una recapitulación del sistema electoral español, incluyendo sus rendimientos en las últimas elecciones, celebradas en 2015 y 2016. Analizamos así las distintas etapas de su creación, sus elementos constitutivos, sus principales efectos tanto en la dimensión interpartidista como en la intrapartidista, las propuestas formuladas para modificarlo y algunas decisiones controvertidas del Tribunal Constitucional

Low-speed longitudinal controllers for mass-produced cars: A comparative study

Four longitudinal control techniques are compared: a classical Proportional-Integral (PI) control; an advanced technique-called the i-PI-that adds an intelligent component to the PI; a fuzzy controller based on human experience; and an adaptive-network-based fuzzy inference system. The controllers were designed to tackle one of the challenging topics as yet unsolved by the automotive sector: managing autonomously a gasoline-propelled vehicle at very low speeds. The dynamics involved are highly nonlinear and constitute an excellent test-bed for newly designed controllers. A Citroën C3 Pluriel car was modified to permit autonomous action on the accelerator and the brake pedals-i.e., longitudinal control. The controllers were tested in two stages. First, the vehicle was modeled to check the controllers' feasibility. Second, the controllers were then implemented in the Citroën, and their behavior under the same conditions on an identical real circuit was compared

Intelligent automatic overtaking system using vision for vehicle detection

There is clear evidence that investment in intelligent transportation system technologies brings major social and economic benefits. Technological advances in the area of automatic systems in particular are becoming vital for the reduction of road deaths. We here describe our approach to automation of one the riskiest autonomous manœuvres involving vehicles – overtaking. The approach is based on a stereo vision system responsible for detecting any preceding vehicle and triggering the autonomous overtaking manœuvre. To this end, a fuzzy-logic based controller was developed to emulate how humans overtake. Its input is information from the vision system and from a positioning-based system consisting of a differential global positioning system (DGPS) and an inertial measurement unit (IMU). Its output is the generation of action on the vehicle’s actuators, i.e., the steering wheel and throttle and brake pedals. The system has been incorporated into a commercial Citroën car and tested on the private driving circuit at the facilities of our research center, CAR, with different preceding vehicles – a motorbike, car, and truck – with encouraging results

Comparing fuzzy and intelligent PI controllers in stop-and-go manoeuvres

The aim of this work was twofold: on the one hand, to describe a comparative study of two intelligent control techniques-fuzzy and intelligent proportional-integral (PI) control, and on the other, to try to provide an answer to an as yet unsolved topic in the automotive sector-stop-and-go control in urban environments at very low speeds. Commercial vehicles exhibit nonlinear behavior and therefore constitute an excellent platform on which to check the controllers. This paper describes the design, tuning, and evaluation of the controllers performing actions on the longitudinal control of a car-the throttle and brake pedals-to accomplish stop-and-go manoeuvres. They are tested in two steps. First, a simulation model is used to design and tune the controllers, and second, these controllers are implemented in the commercial vehicle-which has automatic driving capabilities-to check their behavior. A stop-and-go manoeuvre is implemented with the two control techniques using two cooperating vehicles

La controvertida nacionalidad de Ricardo Maduro Joest, candidato a la Presidencia de la República de Honduras.

Con independencia de una eventual aplicación retroactiva de los preceptos sobre nacionalidad de la vigente Constitución hondureña, el relato fáctico puesto en relación con los sucesivos cambios legislativos acaecidos en Honduras y con la incorporación a Convenios internacionales de este país, es totalmente favorable a la consideración de que Ricardo Maduro Joest posee la nacionalidad hondureña por nacimiento y que junto a otras circunstancias personales que en él concurren esta en plenitud, por ende, de los derechos de ciudadanía que tal modalidad de nacionalidad confiere

Cell death in the developing vertebrate limb: A locally regulated mechanism contributing to musculoskeletal tissue morphogenesis and differentiation

Our aim is to critically review current knowledge of the function and regulation of cell death in the developing limb. We provide a detailed, but short, overview of the areas of cell death observed in the developing limb, establishing their function in morphogenesis and structural development of limb tissues. We will examine the functions of this process in the formation and growth of the limb primordia, formation of cartilaginous skeleton, formation of synovial joints, and establishment of muscle bellies, tendons, and entheses. We will analyze the plasticity of the cell death program by focusing on the developmental potential of progenitors prior to death. Considering the prolonged plasticity of progenitors to escape from the death process, we will discuss a new biological perspective that explains cell death: this process, rather than secondary to a specific genetic program, is a consequence of the tissue building strategy employed by the embryo based on the formation of scaffolds that disintegrate once their associated neighboring structures differentiate.Spanish Science and Innovation Ministry, Grant/Award Numbers: BFU2017-84046-P, BES-2015-07426

Vision-based active safety system for automatic stopping

ntelligent systems designed to reduce highway fatalities have been widely applied in the automotive sector in the last decade. Of all users of transport systems, pedestrians are the most vulnerable in crashes as they are unprotected. This paper deals with an autonomous intelligent emergency system designed to avoid collisions with pedestrians. The system consists of a fuzzy controller based on the time-to-collision estimate – obtained via a vision-based system – and the wheel-locking probability – obtained via the vehicle’s CAN bus – that generates a safe braking action. The system has been tested in a real car – a convertible Citroën C3 Pluriel – equipped with an automated electro-hydraulic braking system capable of working in parallel with the vehicle’s original braking circuit. The system is used as a last resort in the case that an unexpected pedestrian is in the lane and all the warnings have failed to produce a response from the driver

HACIA UN CURRÍCULO FLEXIBLE: SALIDAS INTERMEDIAS Y CURSOS OPTATIVOS

Traditionally, the curricula of the university degree courses have been focused on the formation of professionals within the required period for their graduation (5-6 years), with a single exit to the labour market. This research is aimed at contributing, from the Labour and Professional Formation of the students, to the definition of their formative process, according to their needs and interests. This paper also analyses the advantages of the intermediate exits in a university degree course, and how they allow students to obtain a college degree without affecting the continuation of the higher education studies or the quality of the formation of the university graduate. Such reality favours the insertion of the students in the labour market under conditions that suit the qualifications and experience related to the degree they are doing. From the curricular perspective, the proposal is based on flexible curricula with intermediate exits, where optional and/or elective courses can be of great importance.Tradicionalmente los currículos de las carreras universitarias se han caracterizado por el predominio de una formación de tipo terminal con una sola salida al mercado laboral. Con el fin de contribuir de manera flexible desde la Formación Laboral y Profesional a que los estudiantes definan su trayectoria formativa, en este trabajo se analizan las ventajas de las salidas intermedias en una carrera universitaria, sin afectar la continuidad de los estudios superiores ni la calidad en la formación del egresado universitario. Estas permiten a los estudiantes obtener un título de nivel medio que los pone en condiciones de salir al mercado laboral con un perfil ocupacional relacionado con la carrera universitaria que estudia. Desde la perspectiva curricular la propuesta realizada se basa en currículos flexibles con salidas intermedias donde pueden ser de gran utilidad los cursos optativos y/o electivos

Caracterización del EVA de módulos FV por comparación con filtros plásticos

En un trabajo anterior se presentó el estudio del daño sufrido en los módulos fotovoltaicos después de varios años de exposición a la intemperie, donde se relaciona la pérdida de potencia con la degradación del encapsulante. En este trabajo se muestran algunos resultados obtenidos de la caracterización del material transparente constituido por varias capas de material encapsulante a base de geles de siliconas (etileno vinilo acetileno, EVA), por comparación con la disminución de la trasmitancia provocada por el agregado de filtros plásticos. Se busca también la caracterización del polvo acumulado sobre la superficie del panel. Se concluye que la pérdida de potencia por la degradación de este material no es despreciable.In a previous paper we presented the study of the damage suffered by the PV modules after several years of outdoor exposure, relating the loss of power with EVA degradation. In this article we show some results obtained from the characterization of the transparent material constituted by several sheets of capping encapsulating material based on silicone gels in comparison with the decrease of the transmittance by the addition of plastic filters. The characterization of accumulated dust on the surface is also being searched. We can conclude that the loss of power by the degradation of this material is not negligible.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES