Auto-consistent metallicity and star formation history of the nearest blue compact dwarf galaxy NGC 6789

We present a detailed auto-consistent study of the nearest blue compact dwarf galaxy NGC 6789 by means of optical and UV archive photometry data and optical long-slit ISIS-WHT spectroscopy observations of the five brightest star-forming knots. The analysis of the spectra in all knots allowed the derivation of ionic chemical abundances of oxygen, nitrogen, sulphur, argon and neon using measures of both the high- and low-excitation electron temperatures, leading to the conclusion that NGC 6789 is chemically homogeneous with low values of the abundance of oxygen in the range 12+log(O/H) = 7.80-7.93, but presenting at the same time higher values of the nitrogen-to-oxygen ratio than expected for its metal regime. We used archival HST/WFPC2 F555W and F814W observations of NGC 6789 to perform a photometric study of the colour-magnitude diagram (CMD) of the resolved stellar populations and derive its star formation history (SFH), which is compatible with the presence of different young and old stellar populations whose metallicities do not necessarily increase with age. We fit the observed optical spectrum in all the five knots using the STARLIGHT code and a combination of single stellar populations following the SFH obtained from the CMD. We compare the resulting stellar masses and the relative fractions of the ionising populations with a non-constrained SFH case. The properties of the younger populations were obtained using CLOUDY photoionisation models, giving similar ages in all the knots in the range 3-6 Myr and the estimation of the dust absorption factor, which correlates with the observed GALEX FUV-NUV colour indices. The total photometric extinction and dust-absorption corrected H\alpha\ fluxes were finally used to derive the star formation rates.Comment: 18 pages, 6 figures, 10 tables; accepted by MNRA

Evaluating the more suitable ISM frequency band for iot-based smart grids: a quantitative study of 915 MHz vs. 2400 MHz

IoT has begun to be employed pervasively in industrial environments and critical infrastructures thanks to its positive impact on performance and efficiency. Among these environments, the Smart Grid (SG) excels as the perfect host for this technology, mainly due to its potential to become the motor of the rest of electrically-dependent infrastructures. To make this SG-oriented IoT cost-effective, most deployments employ unlicensed ISM bands, specifically the 2400 MHz one, due to its extended communication bandwidth in comparison with lower bands. This band has been extensively used for years by Wireless Sensor Networks (WSN) and Mobile Ad-hoc Networks (MANET), from which the IoT technologically inherits. However, this work questions and evaluates the suitability of such a "default" communication band in SG environments, compared with the 915 MHz ISM band. A comprehensive quantitative comparison of these bands has been accomplished in terms of: power consumption, average network delay, and packet reception rate. To allow such a study, a dual-band propagation model specifically designed for the SG has been derived, tested, and incorporated into the well-known TOSSIM simulator. Simulation results reveal that only in the absence of other 2400 MHz interfering devices (such as WiFi or Bluetooth) or in small networks, is the 2400 MHz band the best option. In any other case, SG-oriented IoT quantitatively perform better if operating in the 915 MHz band.This research was supported by the MINECO/FEDER project grants TEC2013-47016-C2-2-R (COINS) and TEC2016-76465-C2-1-R (AIM). The authors would like to thank Juan Salvador Perez Madrid nd Domingo Meca (part of the Iberdrola staff) for the support provided during the realization of this work. Ruben M. Sandoval also thanks the Spanish MICINN for an FPU (REF FPU14/03424) pre-doctoral fellowship

Dimensionality reduction and spectral properties of multilayer networks

Network representations are useful for describing the structure of a large variety of complex systems. Although most studies of real-world networks suppose that nodes are connected by only a single type of edge, most natural and engineered systems include multiple subsystems and layers of connectivity. This new paradigm has attracted a great deal of attention and one fundamental challenge is to characterize multilayer networks both structurally and dynamically. One way to address this question is to study the spectral properties of such networks. Here, we apply the framework of graph quotients, which occurs naturally in this context, and the associated eigenvalue interlacing results, to the adjacency and Laplacian matrices of undirected multilayer networks. Specifically, we describe relationships between the eigenvalue spectra of multilayer networks and their two most natural quotients, the network of layers and the aggregate network, and show the dynamical implications of working with either of the two simplified representations. Our work thus contributes in particular to the study of dynamical processes whose critical properties are determined by the spectral properties of the underlying network.Comment: minor changes; pre-published versio

Método Pilates vs. TENS en el dolor lumbar

El dolor lumbar es una de las afecciones más comunes en el ser humano ya que se estima que aproximadamente solo dos de cada diez personas vivirán sin dolor de espalda. Las principales consecuencias de esta patología son el dolor y la discapacidad que generan mucha limitación entre quienes la padecen. Justificación del trabajo: el método Pilates sigue sumando adeptos a todos los niveles. Puesto que la lumbalgia es una afección tan común y el ejercicio está indicado para su recuperación es necesaria la evaluación de la utilidad del método en esta dolencia en comparación con un método de tratamiento tradicional. Objetivo: realizar mediante una revisión bibliográfica una comparación de la eficacia e importancia de un programa basado en el método Pilates frente al TENS (Transcutaneous Electrical Nerve Stimulation) en el dolor lumbar. Metodología: la revisión bibliográfica se ha desarrollado en distintas bases de datos: Medline, PEDro, SciELO, Cochrane Library y Scholar Google. Las palabras clave utilizadas en la búsqueda han sido: pilates and low back pain y tens and low back pain. Resultados: se han localizado un total de 94 documentos, de los cuales 70 fueron descartados, reduciéndose el resultado a 24 artículos válidos para el desarrollo del trabajo. Los aspectos que se valoran se agruparon por bloques para una mejor comprensión de los resultados. Conclusiones: se ha demostrado la efectividad de un método activo de ejercicios específicos (Pilates) frente a uno pasivo (TENS) en el tratamiento del dolor lumbar crónico (DLC).Grado en Fisioterapi

Análisis de los departamentos de comunicación como herramienta para la visibilidad mediática de las entidades deportivas: el caso del Levante UD

Treball Final de Grau en Periodisme. Codi: PE0932. Curs acadèmic 2015-2016La influencia del fútbol en la sociedad es un hecho innegable en los últimos años. Es la disciplina deportiva que más destaca por su capacidad para movilizar a las masas y por la cota de atención que atrae. Este hecho no pasa inadvertido para los medios de comunicación, quienes buscan la rentabilidad económica, y ésta procede en buena medida del logro de grandes audiencias. En un escenario donde los clubes de fútbol son empresas que necesitan comunicar su esencia y manifestar su presencia para llegar a sus seguidores y captar más patrocinadores que aporten ingresos a la entidad, llamar la atención de los medios deviene un objetivo prioritario. Esta cuestión origina la instauración y profesionalización de los departamentos de comunicación en el seno de estas organizaciones. Por eso el estudio de estos organismos es importante, ya que representan una tendencia en auge dentro del contexto y momento actuales. Este trabajo pretende, a través del caso del departamento de comunicación del Levante UD, analizar cuantitativa y cualitativamente la tarea y la relevancia de estos gabinetes a través de la valoración de la repercusión mediática que son capaces de lograr sus acciones así como valorar el rol que desempeñan dentro de los clubes de fútbol y en el marco del periodismo deportivo. Este papel resulta vital actualmente porque aumenta y mejora la calidad de la visibilidad mediática de las organizaciones, especialmente en un momento en que los periodistas no pueden abarcar la ingente cantidad de información a causa de la precarización laboral.The influence of football on society is an undeniable fact in recent years. It is the sport that stands out for its ability to mobilize the masses and for the attention it attracts. This fact doesn’t go unnoticed by the media, who seek profitability and this comes largely from achieving great audience figures. In a scenario where football clubs are companies that need to communicate their essence and manifest their presence to reach their followers and attract more sponsors who provide earnings to the entity, draw media attention becomes a priority. This question leads to the establishment and professionalization of communication departments within these organizations. Because of this the study of these organisms is important since they represent a growing trend within the current context and time. This research aims, through the case of the department of communication of Levante UD, analyze quantitatively and qualitatively the task and the relevance of these cabinets through the assessment of the media coverage that are able to achieve their actions and to evaluate the role they play in football clubs and within the context of sports journalism. This role becomes essential now because it increases and improves the quality of the media visibility of organizations, especially at a time when journalists cannot cover the enormous amount of information because of working precariousness and the lack of means

Does the Spanish 15M have an ideology? Issues of method and measurement

El objetivo de este texto es aproximarse a las implicaciones de utilizar dos métodos de investigación y supuestos analíticos diferentes al estudio de los movimientos sociales. Para desarrollar y discutir este aspecto, me centro en el análisis de la emergencia de un movimiento social que impactó a la sociedad española en 2011: el movimiento 15M de los 'indignados. Particularmente confronto las principales conclusiones de dos aproximaciones metodológicas que analizan su emergencia, centrando mi interés en las raíces ideológicas de su identidad colectiva. La primera aproximación tiene su base primordialmente en datos etnográficos (Laraña y Díez, 2012a; 2012b) y la segunda utiliza datos estadísticos agregados. Mientras que en trabajos previos hemos destacado los aspectos más micro e intersubjetivos de la acción social, mediante la utilización de técnicas etnográficas, que nos permitieron estudiar cómo los activistas organizan las acciones del movimiento, difunden sus marcos y construyen su identidad colectiva, este texto se centran en datos agregados de origen estadístico con el objetivo de: i) analizar las bases ideológicas de este movimiento, ii) comparar los resultados obtenidos en relación a esta cuestión desde las aproximaciones anteriormente mencionadas, y iii) hacer notar sus complementariedades.The broad aim of this paper is to look into the implications of applying two different methods of research and analytical assumptions to the study of social movements. In order to develop and discuss this aim, I focus my analysis on the emergence of a social movement that impacted Spanish society in 2011: the 'indignados' movement 15M. Particularly, in this case, I confront the main conclusions of two different methodological approaches that analyze the emergence of the movement, focusing my interest in the ideological roots of its collective identity. The first approach is mainly based on ethnographic data (Laraña & Díez, 2012a; 2012b) and the second one consists of a statistical macro-analysis. Whereas in the two first works we highlighted the most micro and intersubjective aspects of the social action, through ethnographic techniques, that allowed us to study how the activists organize the actions of the movement, spread their frames and construct its collective identity, this paper mainly focuses on macro statistical data in order to: i) analyze the ideological bases of the movement, ii) compare the results obtained regarding this issue from the both aforementioned approaches, and iii) look at their complementarities

A new countermeasure against side-channel attacks based on hardware-software co-design

This paper aims at presenting a new countermeasure against Side-Channel Analysis (SCA) attacks, whose implementation is based on a hardware-software co-design. The hardware architecture consists of a microprocessor, which executes the algorithm using a false key, and a coprocessor that performs several operations that are necessary to retrieve the original text that was encrypted with the real key. The coprocessor hardly affects the power consumption of the device, so that any classical attack based on such power consumption would reveal a false key. Additionally, as the operations carried out by the coprocessor are performed in parallel with the microprocessor, the execution time devoted for encrypting a specific text is not affected by the proposed countermeasure. In order to verify the correctness of our proposal, the system was implemented on a Virtex 5 FPGA. Different SCA attacks were performed on several functions of AES algorithm. Experimental results show in all cases that the system is effectively protected by revealing a false encryption key.Peer ReviewedPreprin

Hardware architecture implemented on FPGA for protecting cryptographic keys against side-channel attacks

This paper presents a new hardware architecture designed for protecting the key of cryptographic algorithms against attacks by side-channel analysis (SCA). Unlike previous approaches already published, the fortress of the proposed architecture is based on revealing a false key. Such a false key is obtained when the leakage information, related to either the power consumption or the electromagnetic radiation (EM) emitted by the hardware device, is analysed by means of a classical statistical method. In fact, the trace of power consumption (or the EM) does not reveal any significant sign of protection in its behaviour or shape. Experimental results were obtained by using a Virtex 5 FPGA, on which a 128-bit version of the standard AES encryption algorithm was implemented. The architecture could easily be extrapolated to an ASIC device based on standard cell libraries. The system is capable of concealing the real key when various attacks are performed on the AES algorithm, using two statistical methods which are based on correlation, the Welch’s t-test and the difference of means.Peer ReviewedPostprint (author's final draft