Controlling the path of discretized light in waveguide lattices

A general method for flexible control of the path of discretized light beams in homogeneous waveguide lattices, based on longitudinal modulation of the coupling constant, is theoretically proposed. As compared to beam steering and refraction achievable in graded-index waveguide arrays, the proposed approach enables to synthesize rather arbitrary target paths

Las elecciones europeas de 2009 y el espectro de la extrema derecha

Las recientes elecciones europeas han supuesto un éxito para los grupos de la extrema derecha xenófoba y nacionalista. La derecha radical o extrema derecha ha ganado posiciones progresivamente en el Parlamento Europeo desde las primeras elecciones en 1979. En las últimas, los diferentes partidos ocupan un total de 35 escaños, pero la gran diversidad de posiciones en su interior hace difícil su colaboración en un solo grupo parlamentario y por tanto su influencia política directa en la UE seguirá siendo pequeña. Un problema diferente es su influencia indirecta a través de los Estados nacionales, especialmente en lo relativo a las políticas migratorias

El nacionalismo minoritario, de la marginalidad al gobierno : la trayectoria del Bloque Nacionalista Galego (1982-2007)

¿Cómo se explica la evolución de un partido nacionalista minoritario, de la marginalidad política al gobierno? La tercera ola de movilización nacionalista en Europa definió un nuevo espacio político para partidos nacionalistas sin representación política previa. Este artículo analiza esta trayectoria, desde los fracasos iniciales hasta el gobierno, utilizando el caso del BNG en Galicia. Se define, en primer lugar, el «ciclo vital» del partido en sus distintas fases de desarrollo, desde las posiciones antisistema hasta su participación en el gobierno autonómico. Posteriormente, se explica el impacto de estos procesos, tanto en las dinámicas internas y organizativas, como en los objetivos perseguidos por el partido a lo largo de su trayectoria. En síntesis, las decisiones sobre los objetivos partidistas fueron decisiones «blandas» de adaptación gradual al contexto político e institucional, pero transformaron la identidad y la dinámica organizativa del partido.What implications does the evolution of minor nationalist parties from marginality to government for party internal dynamics? The third wave of nationalist mobilization in Europe defined a new political space for nationalist parties without previous political representation. This article analyzes this specific trajectory, from initial failures to government, using the case of the Galicia BNG. It explains the impact of expanding political space for internal party dynamics and organization, as well as reshaping party objectives over time. In short, decisions about party objectives were 'soft', of gradual adaptation to the institutional and political context, yet they radically transformed the identity and organizational dynamics of the BNG

Validation of flacs code for risk analysis of hydrocarbon pool fires

Fires have been object of study over the last decades due to their destructive power. Fire’s hazardous nature and its ability to inflict damage to property, the environment and people, has produced a need to understand how it works in every aspect. Currently, the main focus is to estimate the fire characteristics and main effects, in order to accurately design emergency plans and prevention measures. Due to the needs previously stated, fires have been studied and analyzed mainly from an experimental point of view. However, experimental data is arduous and extremely expensive to obtain due to the amount of resources needed. Additionally, small-scale models, which are generally easier to be undertaken, cannot be extrapolated to full-scale models. Considering this, semi-empirical methods were developed, but can only be applied to simple scenarios and they cannot fully model them. To achieve complete models of fires, CFD (Computational Fluid Dynamics) modeling has been recently used as a way to achieve a cheaper and easier method to study the fire development of full-scale fires in a wide range of conditions. Nevertheless, CFD models require a huge validation effort before they could be widely applied. The main objective of this thesis is to analyze the performance and if possible validate the CFD code FLACS-Fire v10.5 (Flame Accelerator Simulator) for pool-fires. FLACS is a Computational Fluid Dynamic (CFD) program, which solves the compressible conservation equations for mass, momentum, enthalpy, and mixture fraction using a finite volume method. To model a fire it is necessary to include, among others, processes that involve submodels for: turbulence, combustion, thermal radiation, and soot generation. It is of utmost importance, while developing fire models, to validate them against experimental data in pursuance of being able to conclude whether the simulation is valid or not, and to determine the inherent error in comparison with reality. This process consists in a replication of the experimental setup in the CFD, in this case FLACS, and compare it with experimental data previously available. In the present work, gasoline and diesel fuel experimental pool fires were modeled with FLACS-Fire v10.5 code. Simulations considered different pool fire experiments with diameters ranging from 1.5 to 4 meters. In addition, simulations were run with the Eddy Dissipation Concept (EDC) as combustion model; with the κ-ε model as turbulence model; and with the Discrete Transfer Model (DTM) as the radiation model. The predicted results of temperature’s evolution at different heights, burning rate, and thermal radiation were compared with experimental measurements. The results for gasoline and diesel pool fires indicate that FLACS-Fire v10.5 is able to model pool fires. Pool model 3 (PM3) was able to run all simulations, and Pool Model 1 (PM1) does not perform well with pool diameters higher than 1.5m. Predicted values of the proposed parameters are in a fair concordance with experimentally obtained values. Temperatures measured at the centerline of the flame are in most cases overestimated. Burning rates are well approximated with small and large pool fires (0.15 kg/s-0.5kg/s) but largely over predicted in gasoline pool fires of medium size. Thermal radiation is also forecasted with values larger than their experimental counterparts. Chapter 1, contains a brief introduction to the master thesis. It gives a general understanding of the importance of pool fires in the industry. It also gives a global introduction to Computational Fluid Dynamics (CFD), and its relevancy in the study of accidents, especially in the case of pool fires. Chapter 2, consists of a theoretical background of fire phenomena and the combustion process, with a special focus on pool fires. First, a brief and simple explanation of the combustion process is given. Then, an introduction to heat transfer is provided, in order to show the essentials of how thermal energy is transferred and how it affects pool fires. Finally, an introduction to pool fires characteristics and their mechanisms is given, with an emphasis on the zones composing the fire as well as its main features. Chapter 3, mainly covers the existing work concerning the ongoing topic. It covers authors who have worked with pool fires, especially in the validation of FLACS-Fire; as well as others who gather experimental data. Chapter 4, comprises the crucial elements in fire modeling using FLACS-Fire v10.5. Principally, it contains the submodels FLACS uses for: fluid flow, turbulence, radiation, combustion, soot formation, and pool modeling. This chapter shows a theoretical understanding and the basis from which the simulations are later performed. Chapter 5, is constituted by a detailed explanation of the experimental data used in the present thesis. Instrumentation used in the experiments is thoroughly analyzed, as well as the fuels used and the experiments performed. Chapter 6, includes the simulations performed in the present thesis, as well as, a comprehensive analysis of the data obtained. Initial simulations studying various variables such as grid, radiation model and pool model are studied. Final simulations are also evaluated, which especial emphasis on the discrepancies with the experimental data

Constraints for the existence of flat and stable non-supersymmetric vacua in supergravity

We further develop on the study of the conditions for the existence of locally stable non-supersymmetric vacua with vanishing cosmological constant in supergravity models involving only chiral superfields. Starting from the two necessary conditions for flatness and stability derived in a previous paper (which involve the Kahler metric and its Riemann tensor contracted with the supersymmetry breaking auxiliary fields) we show that the implications of these constraints can be worked out exactly not only for factorizable scalar manifolds, but also for symmetric coset manifolds. In both cases, the conditions imply a strong restriction on the Kahler geometry and constrain the vector of auxiliary fields defining the Goldstino direction to lie in a certain cone. We then apply these results to the various homogeneous coset manifolds spanned by the moduli and untwisted matter fields arising in string compactifications, and discuss their implications. Finally, we also discuss what can be said for completely arbitrary scalar manifolds, and derive in this more general case some explicit but weaker restrictions on the Kahler geometry.Comment: 22 pages, Latex, no figure

Survival of TNF antagonists in spondylarthritis is better than in rheumatoid arthritis. Data from the Spanish registry BIOBADASER

The aim of the present work is to compare drug survival and safety of infliximab, etanercept, and adalimumab (tumor necrosis factor [TNF] antagonists) in spondylarthritis (SpA) with those of rheumatoid arthritis (RA). To this purpose, we analysed the data in BIOBADASER (2000–2005), a drug registry launched in 2000 for long-term follow-up of the safety of these biologics in rheumatic diseases. The rates of drug discontinuation and adverse events (AEs) in SpA (n = 1,524) were estimated and compared with those of RA (n = 4,006). Cox regression analyses were used to adjust for independent factors. Total exposure to TNF antagonists for SpA was 2,430 patient-years and 7,865 for RA. Drug survival in SpA was significantly greater than in RA at 1, 2, and 3 years. The hazard ratio (HR) for discontinuation in SpA compared with RA was 0.66 (95% confidence interval [CI], 0.57–0.76) after adjustment for age, gender, and use of infliximab. The difference remained after controlling for the individual medication and its place in the sequence of treatment. There were fewer SpA patients with AEs (17%) than RA patients (26%; p < 0.001). The HR for AEs in SpA was 0.80 (95% CI, 0.70–0.91) compared with RA after adjustment for age, disease duration, and use of infliximab. In conclusion, due in part to a better safety profile, survival of TNF antagonists in SpA is better than in RA. TNF antagonists are at present a safe and effective therapeutic option for long-term treatment of patients with SpA failing to respond to traditional drugs. Because chronic therapy is necessary, continual review of this issue is necessary

Detección de zonas urbanas en imágenes de satélite radar (SAR)

El objetivo del proyecto es la clasificación de las diferentes regiones urbanas de las ciudades de Shangai y Pekín, realizando un análisis estadístico del valor de los píxel (iluminación) de las imágenes mediante ENVI (User manual Envi, CEE 6150: Introduction to ENVI), que se trata de un entorno de visualización de imágenes; obteniendo diversos histogramas con la frecuencia con la que aparece el valor de determinados pixeles en dichas zonas y encontrando la función de distribución que realizara una mejor aproximación de dichos histogramas. Para este estudio se consideraron dos imágenes de radar de teledetección, de Shangai y Pekín, conseguidas a través del nuevo satélite TerraSar-X. Todo el análisis y la elaboración realizada sobre las imágenes han sido realizadas mediante el programa comercial ENVI (Environment for Visualizing Images), un programa que permite abrir, visualizar y analizar diferentes formatos de imágenes. En el primer y segundo capítulo, tras una introducción a la teledetección, vienen explicadas las características y estructura del satélite. En el tercero se describe el análisis efectuado sobre las imágenes describiendo todas las funciones utilizadas. Viene explicado todo el proceso seguido para una de las imágenes, sabiendo que será el mismo para ambas imágenes. En el cuarto capítulo, vienen analizados los datos obtenidos mediante la función de distribución que pueda realizar una mejor aproximación. En el quinto capítulo, después de una primera parte en la cual se ven las conclusiones del estudio, se analizarán también las líneas futuras para su uso.Escuela Técnica Superior de Ingeniería de TelecomunicaciónUniversidad Politécnica de CartagenaUniversitá di Pavi

A panoramic view of fiber and integrated optics in spain

A general view of the present status of optics and related fields in Spain is presented. The main emphasis is on the relation between optics and some emerging areas such as Optical Communications and Nonlinear Optics. Principal activities of the more important groups are summarized

Switching TNF antagonists in patients with chronic arthritis: an observational study of 488 patients over a four-year period

The objective of this work is to analyze the survival of infliximab, etanercept and adalimumab in patients who have switched among tumor necrosis factor (TNF) antagonists for the treatment of chronic arthritis. BIOBADASER is a national registry of patients with different forms of chronic arthritis who are treated with biologics. Using this registry, we have analyzed patient switching of TNF antagonists. The cumulative discontinuation rate was calculated using the actuarial method. The log-rank test was used to compare survival curves, and Cox regression models were used to assess independent factors associated with discontinuing medication. Between February 2000 and September 2004, 4,706 patients were registered in BIOBADASER, of whom 68% had rheumatoid arthritis, 11% ankylosing spondylitis, 10% psoriatic arthritis, and 11% other forms of chronic arthritis. One- and two-year drug survival rates of the TNF antagonist were 0.83 and 0.75, respectively. There were 488 patients treated with more than one TNF antagonist. In this situation, survival of the second TNF antagonist decreased to 0.68 and 0.60 at 1 and 2 years, respectively. Survival was better in patients replacing the first TNF antagonist because of adverse events (hazard ratio (HR) for discontinuation 0.55 (95% confidence interval (CI), 0.34–0.84)), and worse in patients older than 60 years (HR 1.10 (95% CI 0.97–2.49)) or who were treated with infliximab (HR 3.22 (95% CI 2.13–4.87)). In summary, in patients who require continuous therapy and have failed to respond to a TNF antagonist, replacement with a different TNF antagonist may be of use under certain situations. This issue will deserve continuous reassessment with the arrival of new medications

La relevancia de la mitocondria en el cáncer hepático. Revisión sistemática

Introducción: El cáncer hepático es uno de los tumores más frecuentes a nivel mundial y en el que las terapias actuales no son del todo eficaces, sobre todo en los estadios más avanzados. Son numerosos los datos que orientan hacia las mitocondrias, y sus mecanismos de control de calidad, como armas pronostica y terapéuticas en estos tumores. Objetivos: El objetivo del estudio es el tratar de establecer una relación entre la mitocondria y el cáncer hepático y poder observar sus implicaciones biológicas y pronósticas. Material y métodos: Se realiza una revisión sistemática de artículos que logren relacionar las proteínas o los procesos mitocondriales con el cáncer de hígado. La revisión parte de una búsqueda bibliográfica en las bases de datos Pubmed, Web of Science, Dialnet y Scielo, donde se cribarán estudios según cumplan criterios de inclusión y exclusión para posteriormente resumir tanto sus objetivos como sus conclusiones. Resultados: Se revisaron un total de 521 artículos de los cuales 32 componen esta revisión sistemática de los cuales un total de 30 tratan sobre la relación de la mitocondria con el cáncer hepático y 2 sobre la implicación de NFY en estos tumores. Conclusiones: La mitocondria intervienen en la fisiopatología del cáncer hepático y sus proteínas junto con NFY suponen marcadores pronósticos y potenciales dianas terapéuticas, aunque su implicación en los procesos fisiopatológicos tumorales aún no sea del todo clara.Introduction: Liver cancer is one of the most common tumors worldwide and in which current therapies are not entirely effective, especially in the most advanced stages. There is several data that claims the mitochondria and their quality control mechanisms as prognosis and therapeutic factors in this tumors. Objective: The aim of the study is to prove a relation between mitochondria and hepatic cancer and to be able to observe its biological and prognostic implications. Methods: A systematic review of articles that manage to relate proteins or mitochondrial processes with liver cancer is carried out. The review starts with a bibliographic search in databases as Pubmed, Web of Science, Dialnet and Scielo; they will be screened in order to meet inclusion and exclusion criteria to later summarize both, objectives and conclusions. Results: A total of 521 articles were reviewed of which 32 make up this systematic review. Thirty of these treat the relation between mitochondria and liver cancer and the other two summarize the implication of NFY in these tumors. Conclusions: Mitochondria are involved in the pathophysiology of liver cancer and, its proteins along with NFY can be prognostic markers and potential therapeutic targets, although its implication in tumor pathophysiological processes is not yet entirely understood.Medicin