Tree-structure Expectation Propagation for Decoding LDPC codes over Binary Erasure Channels

Expectation Propagation is a generalization to Belief Propagation (BP) in two ways. First, it can be used with any exponential family distribution over the cliques in the graph. Second, it can impose additional constraints on the marginal distributions. We use this second property to impose pair-wise marginal distribution constraints in some check nodes of the LDPC Tanner graph. These additional constraints allow decoding the received codeword when the BP decoder gets stuck. In this paper, we first present the new decoding algorithm, whose complexity is identical to the BP decoder, and we then prove that it is able to decode codewords with a larger fraction of erasures, as the block size tends to infinity. The proposed algorithm can be also understood as a simplification of the Maxwell decoder, but without its computational complexity. We also illustrate that the new algorithm outperforms the BP decoder for finite block-siz

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El cuestionario CEVEAPEU. Un instrumento para la evaluación de las estrategias de aprendizaje de los estudiantes universitarios

El objetivo de este trabajo era elaborar y validar un cuestionario de evaluación de las estrategias de aprendizaje de los estudiantes universitarios más completo que los clásicamente utilizados. Para ello utilizamos un diseño de validación de pruebas. Usamos dos muestras de estudiantes universitarios, la primera de 545 estudiantes y la segunda de 1127. Los resultados de consistencia interna, validez de constructo, validez predictiva y estabilidad temporal, recogidos en el texto del artículo, son buenos. El producto final es un cuestionario con dos escalas, seis subescalas, veinticinco estrategias y 88 ítems, más sólido y completo que los anteriormente disponibles

Outer membrane vesicles from cold-adapted antarctic bacteria

Podeu consultar el llibre complet a: http://hdl.handle.net/2445/63704Many Gram-negative, cold-adapted bacteria from the Antarctic environment produce large amounts of extracellular matter with potential biotechnological applications. Transmission electron microscopy (TEM) analysis after high-pressure freezing and freeze substitution (HPF-FS) showed that this extracellular matter is structurally complex, appearing around cells as a netlike mesh, and composed of an exopolymeric substance (EPS) containing large numbers of outer membrane vesicles (OMVs). Isolation, purification and protein profiling via 1D SDS-PAGE confirmed the outer membrane origin of these Antarctic bacteria OMVs. In an initial attempt to elucidate the role of OMVs in cold-adapted strains of Gram-negative bacteria, a proteomic analysis demonstrated that they were highly enriched in outer membrane proteins and periplasmic proteins associated with nutrient processing and transport, suggesting that the OMVs may be involved in nutrient sensing and bacterial survival. OMVs from Gram-negative bacteria are known to play a role in lateral DNA transfer, but the presence of DNA in these vesicles has remained difficult to explain. A structural study of Shewanella vesiculosa M7T using TEM and Cryo-TEM revealed that this Antarctic Gram-negative bacterium naturally releases conventional one-bilayer OMVs, together with a more complex type of OMV, previously undescribed, which on formation drags along inner membrane and cytoplasmic content and can therefore also entrap DNA

Técnicas experimentales aplicadas al condicionamiento clásico de preferencias en el comportamiento del consumidor

Classical conditioning (CC) is one of the most emblematic developments of experimentalpsychology and psychological science. CC has implied to its area of knowledge: a matterof research, a set of concepts, a methodology, and, finally, a series of technological andinstrumental developments. Like investigation strategy, CC has been used in the study ofa great diversity of processes like perception,learning, memory, and thought. In the sameway,CC is a procedure that has been extended to an important number of applicationfields where it looks for to take part on concrete behavior changes. More specifically, inthe field of consumer behavior, CC are one of the most influential paradigms because itsgreat utility in the explanation on how preferences on goods and services are acquired andmodified. This article pretends introduce to the experimental procedures in CC and CC ofpreferences, in order to indicate their concepts, variables, special phenomena, and researchopportunities.El condicionamiento clásico (CC) es uno de los desarrollos más emblemáticos de la psicología experimental y la ciencia psicológica. CC ha implicado en su área de conocimiento: una cuestión de investigación, un conjunto de conceptos, una metodología y, finalmente, una serie de desarrollos tecnológicos e instrumentales. Al igual que la estrategia de investigación, CC se ha utilizado en el estudio de una gran diversidad de procesos como la percepción, el aprendizaje, la memoria y el pensamiento. De la misma manera, CC es un procedimiento que se ha extendido a un número importante de campos de aplicación donde se busca participar en cambios de comportamiento concretos. Más específicamente, en el campo del comportamiento del consumidor, los CC son uno de los paradigmas más influyentes debido a su gran utilidad en la explicación de cómo se adquieren y se modifican las preferencias sobre bienes y servicios. Este artículo pretende presentar los procedimientos experimentales en CC y CC de las preferencias, a fin de indicar sus conceptos, variables, fenómenos especiales y oportunidades de investigación

An Applied Electromagnetics Course with a Conceiving-Designing-Implementing-Operating Approach in Engineering Education

This paper describes and discusses the implementation of a project-based undergraduate course on applied electromagnetics in electronics engineering with a conceiving-designing-implementing-operating (CDIO) approach involving active project-based learning (PBL). The course, which requires a combination of mathematical and physics concepts for its completion, allows students to understand the principles of electromagnetic transmission theory in wireless communication systems. This paper presents the course proposal, its project description, and results hinting at the relationship with the CDIO process. The proposed projects allow students to engage in core concepts such as complex vectors, Maxwell’s equations, boundary conditions, Poynting\u27s theorem, uniform plane waves, reflection and transmission of waves, waveguides, cavity resonators, and computer-assisted design. The proposed methodology results suggest that students lowered their perception of the difficulty of the course, and most students recognized a better learning process of the core concepts for this course. In addition, students’ final course grades showed an average improvement of approximately 6% compared with the final grades of other groups with different methodologies

Georreferenciando la corrupción urbanística en España

Se plantea que, en el vertiginoso incremento de la actividad urbanística acaecida en España a lo largo de la última década, el papel de la propiedad del suelo sigue teniendo un protagonismo clave en la vida económica de nuestro país. Lo inmobiliario o, en un sentido más amplio, lo urbano -pues hay que añadir las infraestructuras- se materializa sobre el soporte suelo. Pero este soporte, esta base se encuentra dividida, fragmentada por la propiedad privada, la cual, a través de una serie de hechos administrativos (planeamiento) persigue su reclasificación (de rústico a urbano), permitiendo a sus titulares la obtención de rentas millonarias. Y es en este marco en el que se fragua la llamada “corrupción urbanística”, que muestra, con claridad meridiana, la subordinación de la política a los intereses de ciertos grupos económicos (propietarios de suelo, constructores y promotores inmobiliarios). Planteado el problema, se emprendió un amplio estudio que, partiendo del análisis de las fuentes periodísticas y estadísticas oficiales (censos de población y viviendas para los años 1991, 2001 y estimaciones para 2008) y de su tratamiento en bases de datos y Sistemas de Información Geográfica (ArcGis 9.2), ha dado como resultado una variada cartografía a diferentes niveles (municipal, provincial y de comunidades autónomas) del llamado “urbanismo irregular” en España en el período 2000-2010.The last decade witnessed an increase in the urban development activity in Spain. Land ownership has played a crucial role within it. Real state processes take place (materialize) around the element of soil, but the soil turns out to be fragmented by private property. And the latter, through administrative mechanisms, pursues its relabeling from “rural” to “urban”. As a result, big owners of land obtain millionaire incomes. In this context, the so-called “urban development corruption” appears: the subordination of politics to the interests of a number of economic groups (land owners, builders and real estate promoters). A thorough study has been undertaken, which analyzed journalistic sources and official statistics. They were later introduced into a database and a Geographic Information system (Arc gis 9.2). This has yielded a cartography of “irregular urbanism” at different scales (municipal, provincial and autonomous communities) in the period from 2000 to 2010

Effectiveness of a program of romana’s Pilates for non-specific low back pain: A pilot study

Objetivo: comprobar la efectividad del método Pilates Romana para conseguir una mayor flexibilidad de la columna, junto con una mejora en la movilidad de la misma, así como del dolor que presentan en su vida diaria los pacientes. Metodología: ensayo clínico con intención de tratar a treinta pacientes con dolor lumbar inespecífico. Asistieron a 15 sesiones, 2 veces a la semana, del Método Pilates Romana.. Se evaluaron parámetros tales como dolor, test de Schöber, SRS-22 y distancia dedos- suelo. Resultados. Se encontraron diferencias estadísticamente significativas con respecto al dolor (escala EVA), distancia dedos- suelo, test de Schöber (flexibilidad en plano sagital), flexión lateral (flexibilidad en plano frontal) y en varios ítems de la escala SRS-22, con valores de p<0,001. Por ello, este método puede ser usado para mejorar el dolor, la flexibilidad axial, la función y los aspectos relacionados con la calidad de vidaAim: to test the effectiveness of the Romana’s Pilates method to obtain increased flexibility, improvements in mobility, and reduced pain in daily life. Methodology: a clinical trial with intention-to-treat thirty patients with nonspecific low back pain. Participants attended 15 sessions, twice a week. The Romana’s Pilates method was taught by an external physiotherapist. Parameters such as pain, the Schober test, and the SRS-22 were evaluated. Results: Statistically significant differences in pain (VAS), the Schober test (flexibility in sagittal plane), lateral flexion (flexibility in frontal plane) and several items of the SRS-22 scale were found, with p <0.001. This method may be used to improve pain, axial flexibility, function and aspects related to the quality of life of patient