Puente mixto de canto variable sobre la A-30 en Murcia

El puente mixto sobre la A-30 se engloba dentro de las obras para la construcción de la autovía A-33, que conecta 3 corredores de gran importancia entre el centro peninsular y levante, concretamente la A-31 (Madrid-Alicante), la A-30 (Albacete-Cartagena) y la A-35 (Albacete-Valencia); y permite la conexión entre las autovías A-30 y A-33. Para esta estructura se adoptó una tipología del tablero de viga de canto constante con cartelas de refuerzo sobre apoyos, más propia de puentes de hormigón que de puentes mixtos, para lograr una mayor ligereza y transparencia de la estructura. El canto necesario para salvar el gran vano central derivado del esviaje en el cruce de vías y el estricto gálibo previsto, implican la necesidad de disminuir el peso visual del tablero para equilibrarlo con la luz aparente del vano principal, que es la percibida por los usuarios de la vía, y la reducida altura de pilas.

Designer-driven 3D buildings generated using variable neighborhood search

This paper presents a mechanism to generate virtual buildings considering designer constraints and guidelines. This mechanism is implemented as a pipeline of different Variable Neighborhood Search (VNS) optimization processes in which several subproblems are tackled (1) rooms locations, (2) connectivity graph, and (3) element placement. The core VNS algorithm includes some variants to improve its performance, such as, for example constraint handling and biased operator selection. The optimization process uses a toolkit of construction primitives implemented as "smart objects" providing basic elements such as rooms, doors, staircases and other connectors. The paper also shows experimental results of the application of different designer constraints to a wide range of buildings from small houses to a large castle with several underground levels.

Temporally flat top pulse generation from gain switched semiconductor lasers based on a polarization interferometer with variable transfer function

We propose the use of a polarization based interferometer with variable transfer function for the generation of temporally flat top pulses from gain switched single mode semiconductor lasers. The main advantage of the presented technique is its flexibility in terms of input pulse characteristics, as pulse duration, spectral bandwidth and operating wavelength. Theoretical predictions and experimental demonstrations are presented and the proposed technique is applied to two different semiconductor laser sources emitting in the 1550 nm region. Flat top pulses are successfully obtained with input seed pulses with duration ranging from 40 ps to 100 ps.

Efficient information reconciliation for Continuous-Variable QKD using Non-Binary Low-Density Parity-Check Codes

We present here an information reconciliation method and demonstrate for the first time that it can achieve efficiencies close to 0.98. This method is based on the belief propagation decoding of non-binary LDPC codes over finite (Galois) fields. In particular, for convenience and faster decoding we only consider power-of-two Galois fields.

Derivada parcial de un campo vectorial respecto de una variable escalar

La derivación parcial de un campo vectorial respecto de una variable escalar es discutida en este documento tomando el tiempo como ejemplo sin que ello suponga pérdida de generalidad. Las conclusiones obtenidas de dicho análisis también pueden extrapolarse a escenarios donde se usen otras variables escalares, como la frecuencia en electromagnetismo o la temperatura en termodinámica.

La certificación energética: Las instalaciones como variable

El objetivo de este Trabajo Fin de Grado es adentrarse en el mundo de la certificación energética para comprender la importancia que las instalaciones tienen en este ámbito. Una vez realizada la investigación correspondiente, procederemos a realizar un caso práctico en el que aplicaremos todo lo aprendido y servirá para !ijar conocimientos. Cada día mostramos una mayor preocupación respecto a las emisiones de CO2 que producimos, tanto a nivel nacional como internacional, y buscamos posibles soluciones que puedan mejorar estos niveles de contaminación. Muchas son las acciones que podrían llevarse a cabo a este respecto, sin embargo nosotros focalizaremos nuestra investigación en las instalaciones de los edificios. Previamente, realizamos una incursión sobre temas como el marco normativo de la eficiencia energética, la zonificación climática y la etiqueta energética, los cuales forman la base sobre la que se sustenta este trabajo. Así mismo, realizamos una pequeña exploración en el mundo informático para conocer los diferentes programas de certificación que existen en el mercado. Con una ligera idea de los parámetros que maneja cada uno de ellos, elegimos el programa más adecuado para realizar este caso práctico. Una vez adquiridas estas nociones básicas, realizamos un trabajo minucioso de investigación sobre las diferentes medidas de mejora de la certificación energética de los edificios a través de las instalaciones. La implantación de diferentes sistemas como los paneles solares térmicos, los paneles solares fotovoltaicos, la microcogeneración, las calderas de combustión de alta eficiencia, la caldera de biomasa, la bomba de calor, la incorporación de un recuperador de calor o la mejora de la instalación de iluminación son las diferentes opciones que estudiamos. Todas ellas presentan diferentes características pero persiguen el mismo !in, el ahorro de las emisiones de CO2. Por último, con toda la información de la que disponemos, llevamos a cabo la certificación energética de un edificio terciario y valoramos la posible aplicación de las diferentes mejoras en las instalaciones del mismo. En base a las conclusiones del estudio elegiremos las medidas que mejoren notablemente la calificación energética y que resulten más convenientes para el edificio.

Análisis y Diseño de Algoritmos de Control Discreto de Sistemas MIMO Lineales y No Lineales Aplicando Técnicas de Control de Estructura Variable

Dentro de las técnicas de control de procesos no lineales, los controladores de estructura variable con modos deslizantes (VSC-SM en sus siglas en inglés) han demostrado ser una solución robusta, por lo cual han sido ampliamente estudiados en las cuatro últimas décadas. Desde los años ochenta se han presentado varios trabajos enfocados a especificar controladores VSC aplicados a sistemas de tiempo discreto (DVSC), siendo uno de los mayores intereses de análisis obtener las mismas prestaciones de robustez e invarianza de los controladores VSC-SM. El objetivo principal del trabajo de Tesis Doctoral consiste en estudiar, analizar y proponer unos esquemas de diseño de controladores DVSC en procesos multivariable tanto lineales como no lineales. De dicho estudio se propone una nueva filosofía de diseño de superficies deslizantes estables donde se han considerado aspectos hasta ahora no estudiados en el uso de DVSC-SM como son las limitaciones físicas de los actuadores y la dinámica deslizante no ideal. Lo más novedoso es 1) la propuesta de una nueva metodología de diseño de superficies deslizantes aplicadas a sistemas MIMO lineales y la extensión del mismo al caso de sistemas multivariables no lineales y 2) la definición de una nueva ley de alcance y de una ley de control robusta aplicada a sistemas MIMO, tanto lineales como no lineales, incluyendo un esquema de reducción de chattering. Finalmente, con el fin de ilustrar la eficiencia de los esquemas presentados, se incluyen ejemplos numéricos relacionados con el tema tratado en cada uno de los capítulos de la memoria. ABSTRACT Over the last four decades, variable structure controllers with sliding mode (VSC-SM) have been extensively studied, demonstrating to be a robust solution among robust nonlinear processes control techniques. Since the late 80s, several research works have been focused on the application of VSC controllers applied to discrete time or sampled data systems, which are known as DVSC-SM, where the most extensive source of analysis has been devoted to the robustness and invariance properties of VSC-SM controllers when applied to discrete systems. The main aim of this doctoral thesis work is to study, analyze and propose a design scheme of DVSC-SM controllers for lineal and nonlinear multivariable discrete time processes. For this purpose, a new design philosophy is proposed, where various design features have been considered that have not been analyzed in DVSC design approaches. Among them, the physical limitations and the nonideal dynamic sliding mode dynamics. The most innovative aspect is the inclusion of a new design methodology applied to lineal sliding surfaces MIMO systems and the extension to nonlinear multivariable systems, in addition to a new robust control law applied to lineal and nonlinear MIMO systems, including a chattering reduction scheme. Finally, to illustrate the efficiency of the proposed schemes, several numerical examples applied to lineal and nonlinear systems are included.

Estudio y diseño de elementos acústicos para proporcionar una acústica variable en una sala multifuncional

El objetivo de este proyecto es profundizar en el estudio y diseño de sistemas relacionados con el acondicionamiento acústico para una sala multifuncional. El proyecto se compone de dos partes. Una parte teórica y una parte práctica dónde se aplican los conceptos teóricos aprendidos. La primera parte, está dividida en capítulos en los que se habla de los siguientes temas: Acústica de salas. Para obtener una acústica adecuada en un recinto destinado a varias funciones, se debe contar con una serie de características que lo definan según su uso, por lo que es necesario conocer el tiempo de reverberación y otros parámetros subjetivos para poder caracterizar ese recinto. Materiales para el acondicionamiento acústico, donde se habla de los materiales absorbentes clasificándolos según las frecuencias a las que actúan y de los distintos tipos de difusores. Métodos para conseguir una acústica variable mediante la utilización de elementos físicos variables, citando casos reales de salas multifuncionales. La segunda parte, consiste en la realización de diseños de elementos de acústica variable para una posible utilización en salas polivalentes reales. La herramienta elegida a la hora de la elaboración de estos diseños es el AutoCad. Con esta herramienta se han realizado estos diseños representados en dos y tres dimensiones. ABSTRACT. The objective of this project is to deepen the study and design of systems related to multifunctional room acoustic conditioning. The project is composed of two parts. A theoretical part and a practical part where the learned theoretical concepts are applied. The first part is divided into chapters in which we talk about the following topics: Acoustics of rooms. To obtain proper acoustics in a room intended for various functions, you must have a number of characteristics that define it according to its use, so it is necessary to know the reverberation time and other subjective parameters to characterize the hall. Materials for acoustic conditioning, where we talk about the absorbent materials classified according to frequencies that those materials act and the different types of diffusers. Methods for obtain a variable acoustic by using variable physical elements, mentioning real cases of multi-purpose rooms. The second part deals with designs execution of variable acoustic elements for a possible use in a real multipurpose room. The chosen tool to develop these designs is the AutoCad. These designs have been made with this tool, represented in two and three dimensions.

Analysis of microbial populations in Rusitec fermenters fed diets of variable composition

Fermenters are widely used to study ruminal fermentation, but information on microbial populations developing in fermenters over the incubation period is limited. Four Rusitec fermenters were fed 2 diets representative of those administered to dairy sheep(DAI; 50:50 alfalfa hay:concentrate) and fattening lambs (FAT; 15:85 barley straw:concentrate) in a crossover design with 2 14-d incubation periods to assess the evolution of the microbial populations. There were 4 fermenters per diet.

Harvested populations are more variable only in more variable environments

Acknowledgments This work was funded by NERC grant NE/C510467/1 (T. G. Benton and S. B. Piertney) and a University of Leeds Faculty Postdoctoral Fellowship (T. C. Cameron). Data Accessibility The original time series and body size data from these experiments are available to download from DRYAD entry number http://dx.doi.org/10.5061/dryad.bq135.

Defect in IgV gene somatic hypermutation in Common Variable Immuno-Deficiency syndrome

Common Variable Immuno-Deficiency (CVID) is the most common symptomatic primary antibody-deficiency syndrome, but the basic immunologic defects underlying this syndrome are not well defined. We report here that among eight patients studied (six CVID and two hypogammaglobulinemic patients with recurrent infections), there is in two CVID patients a dramatic reduction in Ig V gene somatic hypermutation with 40–75% of IgG transcripts totally devoid of mutations in the circulating memory B cell compartment. Functional assays of the T cell compartment point to an intrinsic B cell defect in the process of antibody affinity maturation in these two cases.

Variable efficacy of repeated annual influenza vaccination

Conclusions have differed in studies that have compared vaccine efficacy in groups receiving influenza vaccine for the first time to efficacy in groups vaccinated more than once. For example, the Hoskins study [Hoskins, T. W., Davis, J. R., Smith, A. J., Miller, C. L. & Allchin, A. (1979) Lancet i, 33–35] concluded that repeat vaccination was not protective in the long term, whereas the Keitel study [Keitel, W. A., Cate, T. R., Couch, R. B., Huggins, L. L. & Hess, K. R. (1997) Vaccine 15, 1114–1122] concluded that repeat vaccination provided continual protection. We propose an explanation, the antigenic distance hypothesis, and test it by analyzing seven influenza outbreaks that occurred during the Hoskins and Keitel studies. The hypothesis is that variation in repeat vaccine efficacy is due to differences in antigenic distances among vaccine strains and between the vaccine strains and the epidemic strain in each outbreak. To test the hypothesis, antigenic distances were calculated from historical hemagglutination inhibition assay tables, and a computer model of the immune response was used to predict the vaccine efficacy of individuals given different vaccinations. The model accurately predicted the observed vaccine efficacies in repeat vaccinees relative to the efficacy in first-time vaccinees (correlation 0.87). Thus, the antigenic distance hypothesis offers a parsimonious explanation of the differences between and within the Hoskins and Keitel studies. These results have implications for the selection of influenza vaccine strains, and also for vaccination strategies for other antigenically variable pathogens that might require repeated vaccination.

A novel multigene family encodes diversified variable regions

Antigen recognition in the adaptive immune response by Ig and T-cell antigen receptors (TCRs) is effected through patterned differences in the peptide sequence in the V regions. V-region specificity forms through genetically programmed rearrangement of individual, diversified segmental elements in single somatic cells. Other Ig superfamily members, including natural killer receptors that mediate cell-surface recognition, do not undergo segmental reorganization, and contain type-2 C (C2) domains, which are structurally distinct from the C1 domains found in Ig and TCR. Immunoreceptor tyrosine-based inhibitory motifs that transduce negative regulatory signals through the cell membrane are found in certain natural killer and other cell surface inhibitory receptors, but not in Ig and TCR. In this study, we employ a genomic approach by using the pufferfish (Spheroides nephelus) to characterize a nonrearranging novel immune-type receptor gene family. Twenty-six different nonrearranging genes, which each encode highly diversified V as well as a V-like C2 extracellular domain, a transmembrane region, and in most instances, an immunoreceptor tyrosine-based inhibitory motif-containing cytoplasmic tail, are identified in an ≈113 kb P1 artificial chromosome insert. The presence in novel immune-type receptor genes of V regions that are related closely to those found in Ig and TCR as well as regulatory motifs that are characteristic of inhibitory receptors implies a heretofore unrecognized link between known receptors that mediate adaptive and innate immune functions.

A family of phase-variable restriction enzymes with differing specificities generated by high-frequency gene rearrangements

The hsd genes of Mycoplasma pulmonis encode restriction and modification enzymes exhibiting a high degree of sequence similarity to the type I enzymes of enteric bacteria. The S subunits of type I systems dictate the DNA sequence specificity of the holoenzyme and are required for both the restriction and the modification reactions. The M. pulmonis chromosome has two hsd loci, both of which contain two hsdS genes each and are complex, site-specific DNA inversion systems. Embedded within the coding region of each hsdS gene are a minimum of three sites at which DNA inversions occur to generate extensive amino acid sequence variations in the predicted S subunits. We show that the polymorphic hsdS genes produced by gene rearrangement encode a family of functional S subunits with differing DNA sequence specificities. In addition to creating polymorphisms in hsdS sequences, DNA inversions regulate the phase-variable production of restriction activity because the other genes required for restriction activity (hsdR and hsdM) are expressed only from loci that are oriented appropriately in the chromosome relative to the hsd promoter. These data cast doubt on the prevailing paradigms that restriction systems are either selfish or function to confer protection from invasion by foreign DNA.

A very limited number of keywords (main patterns) describes all sequences of the human variable heavy (VH) and κ (Vκ) domains

Sequences of the variable heavy (VH) and κ (Vκ) domains of Ig structures were divided into 21 fragments that correspond to strands, loops, or parts of these structural units of the variable domains. Amino acid sequences of fragments (termed “words”) were collected from the 1,172 human heavy and 668 human κ chains available in the Kabat database. Statistical analysis of words of 17 fragments was performed (fragments that comprise the complementary determining regions′ fragments will not be discussed in this paper). The number of different words (those with different residues in at least one position) ranged, for various fragments, from 11 to 75 in the κ chains, and from 23 to 189 in the heavy chains. The main result of this study is that very few keywords, or main patterns of words, were necessary to describe over 90% of the sequences (no more than two keywords per fragment in the κ and no more than five per fragment in the heavy chains). No identical keywords were found for different fragments of the variable domains. Keywords of aligned fragments of the VH and Vκ domains were different in all but two instances. Thus, knowing the keywords, one can determine whether any given small part of a sequence belongs to a heavy or κ chain and predict its precise localization in the sequence. In addition, by using all of the keywords obtained through analysis of the Kabat database, it was possible to describe completely the sequences of the human VH and Vκ germ-line segments.