Long-lived protoplanetary disks in multiple systems: the VLA view of HD 98800

The conditions and evolution of protoplanetary disks in multiple systems can be considerably different from those around single stars, which may have important consequences for planet formation. We present Very Large Array (VLA) 8.8 mm (34 GHz) and 5 cm (6 GHz) observations of the quadruple system HD 98800, which consists of two spectroscopic binary systems (Aa-Ab, Ba-Bb). The Ba-Bb pair is surrounded by a circumbinary disk, usually assumed to be a debris disk given its $\sim$10 Myr age and lack of near infrared excess. The VLA 8.8 mm observations resolve the disk size (5-5.5 au) and its inner cavity ($\approx$3 au) for the first time, making it one of the smallest disks known. Its small size, large fractional luminosity, and millimeter spectral index consistent with blackbody emission support the idea that HD 98800 B is a massive, optically thick ring which may still retain significant amounts of gas. The disk detection at 5 cm is compatible with free-free emission from photoionized material. The diskless HD 98800 A component is also detected, showing partial polarization at 5 cm compatible with non-thermal chromospheric activity. We propose that tidal torques from Ba-Bb and A-B have stopped the viscous evolution of the inner and outer disk radii, and the disk is evolving via mass loss through photoevaporative winds. This scenario can explain the properties and longevity of HD 98800 B as well as the lack of a disk around HD 98800 A, suggesting that planet formation could have more time to proceed in multiple systems than around single stars in certain system configurations.Comment: 14 pages, 4 figures, 3 tables; Submitted to ApJ May 14 2018; Accepted to ApJ August 3 2018. This version fixes a mistake in the reported position angle. The order of the figures has been changed to match that of the references in the tex

El estudio por circuitos magnéticos equivalentes de un motor lineal de flujo mixto

Este proyecto realiza un programa informático que es capaz de: · Realizar un estudio del flujo en una máquina eléctrica lineal utilizando el método de circuitos magnéticos equivalentes (MEC). · Realizar un estudio de las fuerzas obtenidas en la misma máquina mediante la Ley de Lorentz. El método con el que se ha realizado el programa ha sido tal que en principio, el programa es capaz de resolver cualquier tipo de máquina eléctrica lineal. _____________________________________________________________________________________________________An informatic tool is devenveloped in this proyect. This tool can: · Make a complete study of the flux in a linear electric machine. The study is done using the magnetic equivalent circuit. · Make a study of the forces. The study is carried out using the Lorentz’s Law. The informatic tool has been devenveloped allowing a study of any linear electric machine.Ingeniería Industria

Procedimiento para la determinación de la vida residual de tornillos en aerogeneradores

En este proyecto, se pretende abordar el problema económico que surge al sustituir todos los tornillos de las palas de un aerogenerador debido a la rotura de alguno de ellos. Para esto, se estudiará la vida residual de todos los tornillos en función de la posición que ocupen en el aerogenerador. Los resultados obtenidos, permitirán conocer el estado aproximado en que se encuentran los tornillos en cada momento, y así tener la posibilidad de no sustituir aquellos tornillos que estén en condiciones de seguir trabajando. Para llevar a cabo este estudio, será necesario el ensayo a fatiga de un número determinado de tornillos. Por tanto, además de detallar el cálculo de la vida residual de los tornillos, se explicará el procedimiento y equipo necesario para realizar dichos ensayos.The aim of this project is to address the economic problem that arises when some bolts failed in a wind turbine and it is necessary to replace it. Therefore, it will be studied the residual maturity of all the bolts. It will do considering the position of the bolt into de wind turbine. The results obtained will allow it to know about the approximate condition of the bolts in each moment. To carry out this survey it will be necessary a fatigue tests of some specifics bolts. For that, apart from detail of the calculations it will be explained the procedure and the gear necessary to complete this project.Universidad de Sevilla. Grado en Ingeniería de Tecnologías Industriale

Paralelización de un algoritmo de cálculo de la rspuesta impulsional de un canal IR difuso en interiores

Peer Reviewe

Efectos de valoración en la posición de inversión internacional en España

La Posición de Inversión Internacional recoge el valor los activos y pasivos exteriores de una economía en un momento dado. Su evolución en un periodo viene determinada por las transacciones financieras de la Balanza de Pagos, que hacen variar el volumen de los activos y pasivos correspondientes, por las diferencias en la valoración de los stocks debidas a cambios en los precios o en los tipos de cambios y por otros ajustes, que consisten, principalmente, en reclasificaciones de activos exteriores. El objetivo de este trabajo es calcular los efectos de precio y tipo de cambio implícitos en la evolución de la Posición de Inversión Internacional de España y considerar sus posibles limitaciones.

Polyunsaturated fatty acids modify the gating of Kv channels

Polyunsaturated fatty acids (PUFAs) have been reported to exhibit antiarrhythmic properties, which are attributed to their capability to modulate ion channels. This PUFAs ability has been reported to be due to their effects on the gating properties of ion channels. In the present review, we will focus on the role of PUFAs on the gating of two Kv channels, Kv1.5 and Kv11.1. Kv1.5 channels are blocked by n-3 PUFAs of marine [docosahexaenoic acid (DHA) and eicosapentaenoic acid] and plant origin (alpha-linolenic acid, ALA) at physiological concentrations. The blockade of Kv1.5 channels by PUFAs steeply increased in the range of membrane potentials coinciding with those of Kv1.5 channel activation, suggesting that PUFAs-channel binding may derive a significant fraction of its voltage sensitivity through the coupling to channel gating. A similar shift in the activation voltage was noted for the effects of n-6 arachidonic acid (AA) and DHA on Kv1.1, Kv1.2, and Kv11.1 channels. PUFAs-Kv1.5 channel interaction is time-dependent, producing a fast decay of the current upon depolarization. Thus, Kv1.5 channel opening is a prerequisite for the PUFA-channel interaction. Similar to the Kv1.5 channels, the blockade of Kv11.1 channels by AA and DHA steeply increased in the range of membrane potentials that coincided with the range of Kv11.1 channel activation, suggesting that the PUFAs-Kv channel interactions are also coupled to channel gating. Furthermore, AA regulates the inactivation process in other Kv channels, introducing a fast voltage-dependent inactivation in non-inactivating Kv channels. These results have been explained within the framework that AA closes voltage-dependent potassium channels by inducing conformational changes in the selectivity filter, suggesting that Kv channel gating is lipid dependent.This work was supported by SAF 2010-14916 and FIS-RECAVARD06/0014/0025. RECAVA is funded by the Instituto de Salud Carlos III. Cristina Moreno and Angela Prieto hold FPI fellowships. Alvaro Macias is a JAE-predoctoral fellow. Alicia De La Cruz held an RECAVA contract.Peer reviewe

Nuevas técnicas metodologías para el fomento de habilidades transversales y transferencia del conocimiento en universitarios

Knowledge transference and its business potential are very much related to founders’ skills, and especially to the development of their transversal skills. Unfortunately, the time needid to achieve these skills spontaneously penalizes their possibilities. The implementation of pilot experiences in application of agile innovation methodologies such as "Lean Startup" and "Scrum" to real business projects during their incubation and acceleration process at the University of Seville has thrown interesting data about the best work dynamics during the process, with measurements of productivity, the "momentum" of the project, its "focus abilities" or qualitative assessments of those involved in the study. The results reveal a series of advantages and disadvantages derived from the application of these methodologies, which exert influence both on the individual performance and on the group of founders, that in general have turned out to be positive, since they allow to accelerate the maturation process to achieve the skills needed to increase survival ratios, or to conclude that it is not a viable project by making use of significantly less time and resources.La transferencia del conocimiento y su potencial empresarial están muy relacionadas con la capacidad del equipo promotor, y especialmente con el desarrollo de habilidades transversales. Por desgracia, el tiempo necesario para lograr estas habilidades de forma espontánea penaliza sus posibilidades. La puesta en marcha de experiencias piloto de aplicación de metodologías ágiles de innovación como “Lean Startup” y “Scrum” a proyectos empresariales reales durante su proceso de incubación y aceleración en la Universidad de Sevilla ha permitido obtener datos interesantes acerca de la dinámica de trabajo individual y grupal registrada durante el proceso, con mediciones de la productividad, el “nivel de inercia” del proyecto, su “capacidad de foco” o valoraciones cualitativas de los implicados en el estudio. Los resultados descubren una serie de ventajas e inconvenientes derivados de la aplicación de estas metodologías, que ejercen influencia tanto en el desempeño individual como del conjunto de fundadores del proyecto, y en líneas generales han resultado ser positivos, ya que permiten acelerar el proceso de maduración personal hacia la consecución de las habilidades necesarias para incrementar la supervivencia del proyecto, o bien para concluir que no es viable haciendo uso de una cantidad significativamente inferior de tiempo y recursos

Effects of n-3 polyunsaturated fatty acids on cardiac ion channels

This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permissionDietary n-3 polyunsaturated fatty acids (PUFAs) have been reported to exhibit antiarrhythmic properties, and these effects have been attributed to their capability to modulate ion channels. In the present review, we will focus on the effects of PUFAs on a cardiac sodium channel (Nav1.5) and two potassium channels involved in cardiac atrial and ventricular repolarization (Kv) (Kv1.5 and Kv11.1). n-3 PUFAs of marine (docosahexaenoic, DHA and eicosapentaenoic acid, EPA) and plant origin (alpha-linolenic acid, ALA) block Kv1.5 and Kv11.1 channels at physiological concentrations. Moreover, DHA and EPA decrease the expression levels of Kv1.5, whereas ALA does not. DHA and EPA also decrease the magnitude of the currents elicited by the activation of Nav1.5 and calcium channels. These effects on sodium and calcium channels should theoretically shorten the cardiac action potential duration (APD), whereas the blocking actions of n-3 PUFAs on Kv channels would be expected to produce a lengthening of cardiac action potential. Indeed, the effects of n-3 PUFAs on the cardiac APD and, therefore, on cardiac arrhythmias vary depending on the method of application, the animal model, and the underlying cardiac pathologyThis work was supported by SAF2010-14916 and FIS-RECAVA RD06/0014/0025. RECAVA is funded by the Instituto de Salud CarlosII

Peri-Urban Organic Agriculture and Short Food Supply Chains as Drivers for Strengthening City/Region Food Systems-Two Case Studies in Andalucia, Spain

Discussions on food security in the Global North have raised questions about the capacity of peri-urban organic agriculture to provide sufficient healthy food for the urban market. Dealing with food security requires more attention to how to protect peri-urban organic farming systems from urban pressures while strengthening the sustainability of local food systems. Given that short food supply chains (SFSCs) have been proven to be effective at reconnecting people with food production, this study focuses on identifying the barriers that hinder their development and the opportunities derived from the comparative advantage provided by their urban proximity. This study is based on documentary and empirical research addressing food supply chain characteristics in the organic sector. This study is focused on Mediterranean peri-urban agriculture, where, historically, there have been close relationships between the city and the countryside. These relationships are based on the fact that many cities are traditionally located next to areas of high agricultural activity, where a wide variety of vegetables is produced almost continuously due to the relatively mild winter climate. This study deals with two medium-sized metropolitan areas in Andalucía in the south of the Iberian Peninsula—the coastal city of Málaga, which is of a tourist-residential nature, and the inland urban agglomeration of Granada. Our research shows, when compared with other studies, that the local organic food sector seems to have great potential to find innovative solutions based on a collective approach, local embeddedness, and collective knowledge and by prioritizing horizontal and sustainable processes at the local/regional scale.Spanish project SAMUTEREuropean Agricultural Fund for Rural Development (EAFRD)Spanish Ministry of Agriculture, Fisheries, Foodstu ffs and the Environmen