Análisis bibliométrico sobre la relación entre factores personales y profesionales en el baloncesto femenino

[ES] Tradicionalmente, las investigaciones realizadas desde la psicología del deporte se interesan por variables personales que optimizan el rendimiento. No obstante, es sabido que el contexto deportivo influye tanto en el rendimiento profesional como personal. El objeto de esta investigación fue revisar la bibliografía publicada en relación a la influencia bidireccional de variables personales, contextuales y de rendimiento, en la faceta profesional y personal de jugadoras de baloncesto profesional. Los resultados ponen de manifiesto que la práctica totalidad de las investigaciones revisadas se interesan por la influencia de las variables psicológicas en el rendimiento de la deportista. Únicamente hemos encontrado dos estudios que aluden a la influencia del contexto como factor que afecta tanto en la faceta profesional como personal de las deportistas. [EN] Traditionally, sport psychology research is interested in personal variables that optimize the performance. Nevertheless, it is known that the sports context influences as much the professional performance as personal. The aim of this research is to review all published bibliography on mutual relations between personal, contextual and performance variables over both the personal and the professional life of elite women basketball playersl. Results show that practically all reviewed research has been interested in the influence of psychological variables on the sport performance. Only we have found two studies that allude to the influence of the context as factor that affects so much the professional as personal facet of the sportswomen.

Entornos personales y corporativos de aprendizaje (PLE y CLE) como andamiaje en el desarrollo de las estrategias de lectura en la lengua extranjera

Programa de doctorado: Tecnologías de la Información y sus Aplicaciones.

Statistical properties of Radio Halos and the re-acceleration model

Galaxy clusters occupy a special position in the cosmic hierarchy as they are the largest bound structures in the Universe. There is now general agreement on a hierarchical picture for the formation of cosmic structures, in which galaxy clusters are supposed to form by accretion of matter and merging between smaller units. During merger events, shocks are driven by the gravity of the dark matter in the diffuse barionic component, which is heated up to the observed temperature. Radio and hard-X ray observations have discovered non-thermal components mixed with the thermal Intra Cluster Medium (ICM) and this is of great importance as it calls for a “revision” of the physics of the ICM. The bulk of present information comes from the radio observations which discovered an increasing number of Mpcsized emissions from the ICM, Radio Halos (at the cluster center) and Radio Relics (at the cluster periphery). These sources are due to synchrotron emission from ultra relativistic electrons diffusing through µG turbulent magnetic fields. Radio Halos are the most spectacular evidence of non-thermal components in the ICM and understanding the origin and evolution of these sources represents one of the most challenging goal of the theory of the ICM. Cluster mergers are the most energetic events in the Universe and a fraction of the energy dissipated during these mergers could be channelled into the amplification of the magnetic fields and into the acceleration of high energy particles via shocks and turbulence driven by these mergers. Present observations of Radio Halos (and possibly of hard X-rays) can be best interpreted in terms of the reacceleration scenario in which MHD turbulence injected during these cluster mergers re-accelerates high energy particles in the ICM. The physics involved in this scenario is very complex and model details are difficult to test, however this model clearly predicts some simple properties of Radio Halos (and resulting IC emission in the hard X-ray band) which are almost independent of the details of the adopted physics. In particular in the re-acceleration scenario MHD turbulence is injected and dissipated during cluster mergers and thus Radio Halos (and also the resulting hard X-ray IC emission) should be transient phenomena (with a typical lifetime <» 1 Gyr) associated with dynamically disturbed clusters. The physics of the re-acceleration scenario should produce an unavoidable cut-off in the spectrum of the re-accelerated electrons, which is due to the balance between turbulent acceleration and radiative losses. The energy at which this cut-off occurs, and thus the maximum frequency at which synchrotron radiation is produced, depends essentially on the efficiency of the acceleration mechanism so that observations at high frequencies are expected to catch only the most efficient phenomena while, in principle, low frequency radio surveys may found these phenomena much common in the Universe. These basic properties should leave an important imprint in the statistical properties of Radio Halos (and of non-thermal phenomena in general) which, however, have not been addressed yet by present modellings. The main focus of this PhD thesis is to calculate, for the first time, the expected statistics of Radio Halos in the context of the re-acceleration scenario. In particular, we shall address the following main questions: • Is it possible to model “self-consistently” the evolution of these sources together with that of the parent clusters? • How the occurrence of Radio Halos is expected to change with cluster mass and to evolve with redshift? How the efficiency to catch Radio Halos in galaxy clusters changes with the observing radio frequency? • How many Radio Halos are expected to form in the Universe? At which redshift is expected the bulk of these sources? • Is it possible to reproduce in the re-acceleration scenario the observed occurrence and number of Radio Halos in the Universe and the observed correlations between thermal and non-thermal properties of galaxy clusters? • Is it possible to constrain the magnetic field intensity and profile in galaxy clusters and the energetic of turbulence in the ICM from the comparison between model expectations and observations? Several astrophysical ingredients are necessary to model the evolution and statistical properties of Radio Halos in the context of re-acceleration model and to address the points given above. For these reason we deserve some space in this PhD thesis to review the important aspects of the physics of the ICM which are of interest to catch our goals. In Chapt. 1 we discuss the physics of galaxy clusters, and in particular, the clusters formation process; in Chapt. 2 we review the main observational properties of non-thermal components in the ICM; and in Chapt. 3 we focus on the physics of magnetic field and of particle acceleration in galaxy clusters. As a relevant application, the theory of Alfv´enic particle acceleration is applied in Chapt. 4 where we report the most important results from calculations we have done in the framework of the re-acceleration scenario. In this Chapter we show that a fraction of the energy of fluid turbulence driven in the ICM by the cluster mergers can be channelled into the injection of Alfv´en waves at small scales and that these waves can efficiently re-accelerate particles and trigger Radio Halos and hard X-ray emission. The main part of this PhD work, the calculation of the statistical properties of Radio Halos and non-thermal phenomena as expected in the context of the re-acceleration model and their comparison with observations, is presented in Chapts.5, 6, 7 and 8. In Chapt.5 we present a first approach to semi-analytical calculations of statistical properties of giant Radio Halos. The main goal of this Chapter is to model cluster formation, the injection of turbulence in the ICM and the resulting particle acceleration process. We adopt the semi–analytic extended Press & Schechter (PS) theory to follow the formation of a large synthetic population of galaxy clusters and assume that during a merger a fraction of the PdV work done by the infalling subclusters in passing through the most massive one is injected in the form of magnetosonic waves. Then the processes of stochastic acceleration of the relativistic electrons by these waves and the properties of the ensuing synchrotron (Radio Halos) and inverse Compton (IC, hard X-ray) emission of merging clusters are computed under the assumption of a constant rms average magnetic field strength in emitting volume. The main finding of these calculations is that giant Radio Halos are naturally expected only in the more massive clusters, and that the expected fraction of clusters with Radio Halos is consistent with the observed one. In Chapt. 6 we extend the previous calculations by including a scaling of the magnetic field strength with cluster mass. The inclusion of this scaling allows us to derive the expected correlations between the synchrotron radio power of Radio Halos and the X-ray properties (T, LX) and mass of the hosting clusters. For the first time, we show that these correlations, calculated in the context of the re-acceleration model, are consistent with the observed ones for typical µG strengths of the average B intensity in massive clusters. The calculations presented in this Chapter allow us to derive the evolution of the probability to form Radio Halos as a function of the cluster mass and redshift. The most relevant finding presented in this Chapter is that the luminosity functions of giant Radio Halos at 1.4 GHz are expected to peak around a radio power » 1024 W/Hz and to flatten (or cut-off) at lower radio powers because of the decrease of the electron re-acceleration efficiency in smaller galaxy clusters. In Chapt. 6 we also derive the expected number counts of Radio Halos and compare them with available observations: we claim that » 100 Radio Halos in the Universe can be observed at 1.4 GHz with deep surveys, while more than 1000 Radio Halos are expected to be discovered in the next future by LOFAR at 150 MHz. This is the first (and so far unique) model expectation for the number counts of Radio Halos at lower frequency and allows to design future radio surveys. Based on the results of Chapt. 6, in Chapt.7 we present a work in progress on a “revision” of the occurrence of Radio Halos. We combine past results from the NVSS radio survey (z » 0.05 − 0.2) with our ongoing GMRT Radio Halos Pointed Observations of 50 X-ray luminous galaxy clusters (at z » 0.2−0.4) and discuss the possibility to test our model expectations with the number counts of Radio Halos at z » 0.05 − 0.4. The most relevant limitation in the calculations presented in Chapt. 5 and 6 is the assumption of an “averaged” size of Radio Halos independently of their radio luminosity and of the mass of the parent clusters. This assumption cannot be released in the context of the PS formalism used to describe the formation process of clusters, while a more detailed analysis of the physics of cluster mergers and of the injection process of turbulence in the ICM would require an approach based on numerical (possible MHD) simulations of a very large volume of the Universe which is however well beyond the aim of this PhD thesis. On the other hand, in Chapt.8 we report our discovery of novel correlations between the size (RH) of Radio Halos and their radio power and between RH and the cluster mass within the Radio Halo region, MH. In particular this last “geometrical” MH − RH correlation allows us to “observationally” overcome the limitation of the “average” size of Radio Halos. Thus in this Chapter, by making use of this “geometrical” correlation and of a simplified form of the re-acceleration model based on the results of Chapt. 5 and 6 we are able to discuss expected correlations between the synchrotron power and the thermal cluster quantities relative to the radio emitting region. This is a new powerful tool of investigation and we show that all the observed correlations (PR − RH, PR − MH, PR − T, PR − LX, . . . ) now become well understood in the context of the re-acceleration model. In addition, we find that observationally the size of Radio Halos scales non-linearly with the virial radius of the parent cluster, and this immediately means that the fraction of the cluster volume which is radio emitting increases with cluster mass and thus that the non-thermal component in clusters is not self-similar.

Multiwavelenght study of cluster mergers and consequences for the radio emission properties of galaxy clusters

In the present thesis a thourough multiwavelength analysis of a number of galaxy clusters known to be experiencing a merger event is presented. The bulk of the thesis consists in the analysis of deep radio observations of six merging clusters, which host extended radio emission on the cluster scale. A composite optical and X–ray analysis is performed in order to obtain a detailed and comprehensive picture of the cluster dynamics and possibly derive hints about the properties of the ongoing merger, such as the involved mass ratio, geometry and time scale. The combination of the high quality radio, optical and X–ray data allows us to investigate the implications of the ongoing merger for the cluster radio properties, focusing on the phenomenon of cluster scale diffuse radio sources, known as radio halos and relics. A total number of six merging clusters was selected for the present study: A3562, A697, A209, A521, RXCJ 1314.4–2515 and RXCJ 2003.5–2323. All of them were known, or suspected, to possess extended radio emission on the cluster scale, in the form of a radio halo and/or a relic. High sensitivity radio observations were carried out for all clusters using the Giant Metrewave Radio Telescope (GMRT) at low frequency (i.e. ≤ 610 MHz), in order to test the presence of a diffuse radio source and/or analyse in detail the properties of the hosted extended radio emission. For three clusters, the GMRT information was combined with higher frequency data from Very Large Array (VLA) observations. A re–analysis of the optical and X–ray data available in the public archives was carried out for all sources. Propriety deep XMM–Newton and Chandra observations were used to investigate the merger dynamics in A3562. Thanks to our multiwavelength analysis, we were able to confirm the existence of a radio halo and/or a relic in all clusters, and to connect their properties and origin to the reconstructed merging scenario for most of the investigated cases. • The existence of a small size and low power radio halo in A3562 was successfully explained in the theoretical framework of the particle re–acceleration model for the origin of radio halos, which invokes the re–acceleration of pre–existing relativistic electrons in the intracluster medium by merger–driven turbulence. • A giant radio halo was found in the massive galaxy cluster A209, which has likely undergone a past major merger and is currently experiencing a new merging process in a direction roughly orthogonal to the old merger axis. A giant radio halo was also detected in A697, whose optical and X–ray properties may be suggestive of a strong merger event along the line of sight. Given the cluster mass and the kind of merger, the existence of a giant radio halo in both clusters is expected in the framework of the re–acceleration scenario. • A radio relic was detected at the outskirts of A521, a highly dynamically disturbed cluster which is accreting a number of small mass concentrations. A possible explanation for its origin requires the presence of a merger–driven shock front at the location of the source. The spectral properties of the relic may support such interpretation and require a Mach number M < ∼ 3 for the shock. • The galaxy cluster RXCJ 1314.4–2515 is exceptional and unique in hosting two peripheral relic sources, extending on the Mpc scale, and a central small size radio halo. The existence of these sources requires the presence of an ongoing energetic merger. Our combined optical and X–ray investigation suggests that a strong merging process between two or more massive subclumps may be ongoing in this cluster. Thanks to forthcoming optical and X–ray observations, we will reconstruct in detail the merger dynamics and derive its energetics, to be related to the energy necessary for the particle re–acceleration in this cluster. • Finally, RXCJ 2003.5–2323 was found to possess a giant radio halo. This source is among the largest, most powerful and most distant (z=0.317) halos imaged so far. Unlike other radio halos, it shows a very peculiar morphology with bright clumps and filaments of emission, whose origin might be related to the relatively high redshift of the hosting cluster. Although very little optical and X–ray information is available about the cluster dynamical stage, the results of our optical analysis suggest the presence of two massive substructures which may be interacting with the cluster. Forthcoming observations in the optical and X–ray bands will allow us to confirm the expected high merging activity in this cluster. Throughout the present thesis a cosmology with H0 = 70 km s−1 Mpc−1, m=0.3 and =0.7 is assumed.

El español internacional en los medios de comunicación: estudio de un caso de un programa de radio en internet

[ES]El objetivo del presente artículo es demostrar que existe un español internacional (EI) en los medios de comunicación de Hispanoamérica. Para ello, hemos escogido un programa de radio de la norma culta del español Atlántico. Por un lado, analizamos las definiciones que se han realizado del español de los medios de comunicación-lengua especial, Lázaro Carreter, para constatar si coadyuvan a la consolidación del concepto de EI y, por otro lado, realizamos un estudio dialectal con los americanismos léxicos del corpus para verificar hasta qué punto constituyen una isoglosa que impide la inteligibilidad y, por tanto, la no existencia de un EI en los medios de comunicación.

Cognitive radio in HF communications: selective transmission and broadband acquisition

Mención Internacional

Una rassegna di protocolli di routing per reti radio cognitive ad hoc

Questa tesi si propone di presentare e classificare per caratteristiche simili i protocolli di routing che ad oggi sono utilizzati nelle Cognitive Radio Ad Hoc Networks. Pertanto dapprima nel Capitolo 1 si introdurranno le radio cognitive con i concetti che sono alla base di questa tecnologia e le principali motivazioni che hanno portato alla loro nascita e poi al loro sviluppo. Nel Capitolo 2 si parlerà delle cognitive networks o meglio delle cognitive radio networks, e delle loro peculiarità. Nel terzo e nel quarto capitolo si affronteranno le CRAHNs e in particolare quali sono le sfide a cui devono far fronte i protocolli di routing che operano su di essa, partendo dall'esaminare quali sono le differenze che distinguono questa tipologia di rete da una classica rete wireless ad hoc con nodi in grado di muoversi nello spazio (una MANET). Infine nell'ultimo capitolo si cercherà di classificare i protocolli in base ad alcune loro caratteristiche, vedendo poi più nel dettaglio alcuni tra i protocolli più usati.

Radio via Web per le Università: un approccio alle infrastrutture tecnologiche

Linea guida per lo sviluppo e la messa in opera di una Web Radio istituzionale per le Università, completa di confronti con altre Web Radio universitare e descrizione di una funzionalità sviluppata.

Gonzalo Hidalgo Bayal nel panorama narrativo estremegno attuale

A lo largo de los últimos años, la narrativa extremeña ha producido un buen número de autores y obras cuya calidad destaca en el mundo de la literatura española. Entre otros, Luis Landero, Dulce Chacón, J.A. Gabriel y Galán y Eugenio Fuentes han aportado una importante contribución a las letras españolas de las últimas décadas. Gonzalo Hidalgo Bayal, autor que comparte con los antes citados el origen extremeño, se sitúa por ende en una generación literaria importante. La obra de este narrador, nacido en Higuera de Albalat y actualmente residente en Plasencia, no es muy conocida por el gran público. Sin embargo, no cabe duda de que los escritos de Bayal poseen unas calidades de primario valor. Su obra narrativa se puede dividir en dos agrupaciones principales. La primera es un grupo de narraciones breves, constituido por unas memorias (Campo de amapolas blancas), un conjunto de relatos fantásticos (La princesa y la muerte) y dos relatos brevísimos reunidos en un único volumen (El artista del billar). La segunda està formada por cuatro novelas: una es la interpretación moderna del cuento cervantino El celoso extremeño (Amad a la dama) y las demás (Misera fue, señora, la osadía, El cerco oblicuo y Paradoja del interventor) se desarrollan en época contemporánea, aunque en períodos distintos, y están protagonizadas por diferentes personajes. Al parecer es difícil encontrar un hilo conductor que valga para la entera obra del autor de Plasencia. Los diferentes desenlaces, un estilo que muda y protagonistas distintos proporcionan a los relatos hidalguianos cierta aptitud a la metamórfosis. Para comprender eficazmente la obra de Hidalgo hay que analizar, en primer lugar, su pensamiento estético: “En la literatura, a partir del primer fruto maduro, no hay evolución ni progresión, sino un deambular circular [...] las obras de un escritor son como satélites en torno a su materia” (El desierto de Takla Makán). Con referencia a uno de sus grandes maestros, Rafael Sánchez Ferlosio, el autor habla de la producción literaria como de un movimiento circular alrededor de una sustancia central. Esta sustancia central es constante: las diferentes obras del escritor pueden alejarse o acercarse a ella, describriéndola y descubriéndola con mayor o menor eficacia. Un análisis de la obra del propio Gonzalo Hidalgo debe entonces tener en cuenta de la necesidad de considerar esta materia central: relatos y novelas se mueven, formando un círculo que encierra una sustancia constante. Para investigar la materia alrededor de que la obra de Gonzalo Hidalgo se mueve, se han elegido dos téminos fundamentales del cuento. Lugar (o, mejor dicho, espacio) y personaje son ejes necesarios, cuya evolución puede proporcionar indicios sobre las lineas fundamentales que orientan el rumbo de la narrativa del autor. Se analiza entonces la manera en que Hidalgo describe y hace vivir espacios y personajes, y como estos se penetran recíprocamente. En algunos de los cuentos el autor utiliza un lugar (Murania) cuyas características físicas proceden de la realidad. La agrupación periférica de medio tamaño es el ambiente de la mayoría de los relatos de Gonzalo Hidalgo Bayal y la inspiración que la produce se encuentra en Plasencia, lugar de residencia del escritor. La función narrativa del espacio, de todas formas, varía y se hace cada vez más clara y precisa. Murania y los demás lugares realizan, con una evolución que atraviesa los distintos relatos, un rechazo firme e inapelable que excluye el personaje principal de la comunidad formada por los ciudadanos y, finalmente, por la entera humanidad. De forma cada vez más intensa, desde Misera fue, señora, la osadía hasta Paradoja del interventor (que constituye, por ahora, el punto de llegada del recorrido narrativo hidalguiano), el espacio actúa para excluir (y destruir) el protagonista, moral y físicamente. Manuel Simón Viola, en los estudios y en las reseñas dedicadas a Gonzalo Hidalgo Bayal, evidencia como el autor de Plasencia construye un trayecto que reúne sobre todo tres novelas (Misera fue, señora, la osadía, El Cerco oblicuo e Paradoja del interventor). Estas obras, además de tener algunas características comunes (conexiones temporales, temas, voz narradora), se centran en odiseas personales, protagonizadas por personajes distintos pero con un común denominador. El protagonista evoluciona hacia un pesimismo que se hace concreto en la relación con un mundo exterior, mundo que no permite ilusión nuguna. El fracaso inevitable con que el personaje se enfrenta es la única salida posible para los desenlaces del cuento hidalguiano. Al final de una evolución que incluye todos los personajes de la obra de Gonzalo Hidalgo, la resignación, principal característica del protagonista de Paradoja del interventor, se convierte en un rasgo distintivo. La derrota y el fracaso, por otro lado, funcionan de hilo conductor también en las obras de otros autores extremeños: Luis Landero y Dulce Chacón concentran, como Gonzalo Hidalgo, el esfuerzo literario en la descripción de afanes sin realizar. Con estilos y enfoques propios, comparten entonces una materia literaria que se descubre en la evolución del personaje y en la cada vez más clara definición de la función del espacio. La palabra, medio necesario para la trasmisión del mensaje literario, tiene entonces un valor fundamental. Como enseña Rafael Sánchez Ferlosio, a través del lenguaje el ser humano realiza su encuentro con la naturaleza: las relaciones humanas, el derecho, la ética y la literatura revolotean en torno al don de la palabra. El lenguaje literario es, como sugiere Gonzalo Hidalgo en algunos escritos críticos dedicados a la literatura extremeña, un vértice del tríangulo formado con sujeto y realidad. A través de las formas del lenguaje, elemento imprescindible, se expresa la relación entre persona y relidad exterior, entre yo y otro, entre personaje y espacio. En suma, el triángulo formado por lenguaje, sujeto y realidad es la clave para descubrir los mecanismos del “deambular circular” del escritor en torno a su materia.