2,351 research outputs found

    Emergent gauge symmetries: Yang-Mills theory

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    Gauge symmetries remove unphysical states and guarantee that field theories are free from the pathologies associated with these states. In this work we find a set of general conditions that guarantee the removal of unphysical states in field theories describing interacting vector fields. These conditions are obtained through the extension of a mechanism for the emergence of gauge symmetries proposed in a previous article [C. Barcel\'o et al. JHEP 10 (2016) 084] in order to account for non-Abelian gauge symmetries, and are the following: low-energy Lorentz invariance, emergence of massless vector fields describable by an action quadratic in those fields and their derivatives, and self-coupling to a conserved current associated with specific rigid symmetries. Using a bootstrapping procedure, we prove that these conditions are equivalent to the emergence of gauge symmetries and, therefore, guarantee that any theory satisfying them must be equivalent to a Yang-Mills theory at low energies.Comment: 15 pages, no figures; v2: Added minor changes in text to match published versio

    Evaluación del dispositivo Pavement Quality Indicator (PQI) en la determinación de la densidad in situ de mezclas fabricadas con emulsión bituminosa

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    The Pavement Quality Indicator (PQI) is a non-nuclear gauge used for the on-site density measurement of asphalt pavements without the need to extract core samples. Previous studies of hot asphalt mixes found that PQI density readings were very similar to laboratory density measurements of pavement cores. This paper describes the first stage of a research project whose objective is to analyze PQI density measurements of mixes manufactured with an asphalt emulsion binder. The PQI density variability for such mixes was verified and compared with the results obtained with other on-site methods for measuring pavement density.El equipo Pavement Quality Indicator es un dispositivo para la determinación de densidad in situ en pavimentos asfálticos sin extracción de testigos. Las experiencias con este equipo en mezclas bituminosas en caliente, recogidas en diferentes fuentes bibliográficas, muestran que las densidades medidas in situ con el PQI son muy similares a las obtenidas mediante la extracción de testigos. En este artículo se expone la primera etapa de un proyecto de investigación que tiene por objeto analizar los resultados de mediciones efectuadas con PQI en mezclas bituminosas donde se utiliza emulsión asfáltica como ligante. Se comprueba la variabilidad de la densidad obtenida con el equipo para este tipo de mezclas, y se comparan los resultados con otros métodos de medida de densidad in situ

    On Limitations of the Ultrasonic Characterization of Pieces Manufactured with Highly Attenuating Materials

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    Some technical aspects of two Spanish cooperation projects, funded by DPI and Innpacto Programs of the R&D National Plan, are discussed. The objective is to analyze the common belief about than the ultrasonic testing in MHz range is not a tool utilizable to detect internal flaws in highly attenuating pieces made of coarse-grained steel. In fact high-strength steels, used in some safe industrial infrastructures of energy & transport sectors, are difficult to be inspected using the conventional “state of the art” in ultrasonic technology, due to their internal microstructures are very attenuating and coarse-grained. It is studied if this inspection difficulty could be overcome by finding intense interrogating pulses and advanced signal processing of the acquired echoes. A possible solution would depend on drastically improving signal-to-noise-ratios, by applying new advances on: ultrasonic transduction, HV electronics for intense pulsed driving of the testing probes, and an “ad-hoc” digital processing or focusing of the received noisy signals, in function of each material to be inspected. To attain this challenging aim on robust steel pieces would open the possibility of obtaining improvements in inspecting critical industrial components made of highly attenuating & dispersive materials, as new composites in aeronautic and motorway bridges, or new metallic alloys in nuclear area, where additional testing limitations often appear.The Spanish I+D National Plan (MINECO), by funding the Projects: Fundamental Research / DPI2011 – 22438, and INNPACTO Program / IMAAD - IPT-020000-2010-0004

    Desarrollo de la asertividad como instrumento de aprendizaje para alumnos universitarios

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    Uno de los éxitos de un buen proceso formativo es que el alumno sea capaz de manifestar con destreza sus habilidades comunicacionales, entendidas éstas como la capacidad para expresar abiertamente sus opiniones, dudas, sentimientos, actitudes y derechos, pero sin infringir los derechos de los demás. En este límite es donde el docente debe llevar a cabo técnicas que fomenten la comunicación, siempre bajo el respeto, fomentando el uso de un lenguaje asertivo el cual facilita de forma significativa el aprendizaje del alumno

    Uso del Mapa Conceptual como Herramienta Docente para la Asignatura “Series Cronológicas”

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    Esta comunicación es fruto de un proyecto de innovación docente que está siendo desarrollado en la Universidad de Jaén. Los objetivos principales de dicho proyecto son el desarrollo de nuevos sistemas de evaluación basados en el reciente marco educativo EEES y el uso de las nuevas tecnologías TIC con el fin común de elaborar y desarrollar nuevos enfoques metodológicos docentes que faciliten el aprendizaje de los alumnos y mejoren la calidad docente.Concretamente, presentamos un mapa conceptual para la asignatura “Series Cronológicas” perteneciente a la Diplomatura en Estadística. Este mapa proporcionará al alumno una magnifica herramienta para asimilar mejor las diferentes técnicas que comprenden la modelización de procesos ARIMA

    Transcriptional Regulator CNOT3 Defines an Aggressive Colorectal Cancer Subtype.

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    Cancer cells exhibit dramatic alterations of chromatin organization at cis-regulatory elements, but the molecular basis, extent, and impact of these alterations are still being unraveled. Here, we identify extensive genome-wide modification of sites bearing the active histone mark H3K4me2 in primary human colorectal cancers, as compared with corresponding benign precursor adenomas. Modification of certain colorectal cancer sites highlighted the activity of the transcription factor CNOT3, which is known to control self-renewal of embryonic stem cells (ESC). In primary colorectal cancer cells, we observed a scattered pattern of CNOT3 expression, as might be expected for a tumor-initiating cell marker. Colorectal cancer cells exhibited nuclear and cytoplasmic expression of CNOT3, suggesting possible roles in both transcription and mRNA stability. We found that CNOT3 was bound primarily to genes whose expression was affected by CNOT3 loss, and also at sites modulated in certain types of colorectal cancers. These target genes were implicated in ESC and cancer self-renewal and fell into two distinct groups: those dependent on CNOT3 and MYC for optimal transcription and those repressed by CNOT3 binding and promoter hypermethylation. Silencing CNOT3 in colorectal cancer cells resulted in replication arrest. In clinical specimens, early-stage tumors that included >5% CNOT3(+) cells exhibited a correlation to worse clinical outcomes compared with tumors with little to no CNOT3 expression. Together, our findings implicate CNOT3 in the coordination of colonic epithelial cell self-renewal, suggesting this factor as a new biomarker for molecular and prognostic classification of early-stage colorectal cancer. Cancer Res; 77(3); 766-79. ©2016 AACR

    Implementation of Signal Processing Methods in a Structural Health Monitoring (SHM) System based on Ultrasonic Guided Waves for Defect Detection in Different Materials and Structures

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    The local defect inspection in longitudinal structures such as plates or pipelines implies high economical costs and it is time consuming mainly in underground infrastructures, energy or water, and aerospace sectors. Moreover, if these structures are non-accessible, their local inspection is not possible. Ultrasonic (US) inspection technique based on guided waves is one of the potential alternatives to address this issue. The US inspection based on these type of waves could be applied in many scenarios to monitor the damage state of structures; i.e., in water underground pipelines to identify the wall thickness losses or impact damage detection on Carbon Fiber Reinforced Composites (CFRC). A SHM system based on guided waves requires a special signal processing in order to identify possible damage in the structure. The signal emitted and received is a combination of different propagation modes which are difficult to identify and analyse. However, if the signals are compared to each other (signal related to non-damaged components compared to damaged signal) it is possible to measure their difference as a distance that can be used to estimate the damage level. In this work, signals corresponding to non-damaged samples have been captured and then different types of damage have been applied for different cases. After the data acquisition phase, the comparison between signals has been carried out by applying different mathematical methods and distance metrics (SDC, DTW, Euclidean, Manhattan and Chebyshev), with the aim of detecting defects in different structures and materials. For this purpose, two cases have been analysed: 1) In CFRC plates subjected to impact damage and deformations and 2) In a pipe coated by cement-mortar in order to quantify the wall thickness losses. In both cases ultrasonic PZT sensors, an ultrasonic multichannel pulser/receiver and a software developed ad-hoc have been used. Although the SHM system components were similar, it must be noted that the type of ultrasonic guided waves used were different; in the case of CFRC plates, Lamb waves were excited whereas in the case of the pipeline, Love waves have been used. A comparison between the above mentioned methods is provided. The results show the validity of the approach for damage characterization.Authors would like to acknowledge the Basque Government funding within the ELKARTEK Programme (AIRHEM)

    Evaluación del comportamiento mecánico de mezclas asfálticas templadas con 100 % de material reciclado

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    The use of Half Warm Mixes with high Reclaimed Asphalt content (HWMRA) has the potential to generate significant environmental advantages such as the reduction in consumption of natural resources and the emission of gases into the atmosphere. This paper therefore focuses on demonstrating the viability of using these types of mixes in wearing courses. For this purpose, an HWMRA with 70 % and 100 % Reclaimed Asphalt Pavement (RAP) and emulsion were designed in the laboratory. The performance of the mixes was then assessed and compared with that of conventional Hot Mix Asphalt. In a second stage, the mixes were manufactured in-plant, and laid and compacted in an Accelerated Pavement Test track. The cores were then extracted and tested for stiffness modulus and resistance to fatigue. The results from the tests conducted with both the laboratory specimens and the cores showed that the performance of HWMRA is comparable to that of HMA. These findings encourage greater confidence in promoting the use of these types of sustainable asphalt mixes.La utilización de mezclas asfálticas templadas con alto contenido de asfalto reciclado (HWMRA) conlleva ventajas medioambientales como la reducción del consumo de recursos naturales y la emisión de gases a la atmósfera. Este artículo se centra en mostrar la viabilidad de este tipo de mezclas para capas de rodadura. Para ello, se diseñaron mezclas HWMRA con 70 % y 100 % de asfalto reciclado en el laboratorio y se evaluó y comparó su comportamiento con una mezcla caliente convencional. En una segunda etapa, las mezclas fueron fabricadas en planta, extendidas y compactadas en una pista de ensayo acelerado de pavimentos. A continuación, se extrajeron testigos y se ensayaron para conocer su módulo de rigidez y resistencia a fatiga. Tanto los resultados de laboratorio como tras la fabricación en planta y puesta en obra mostraron que el comportamiento de mezclas HWMRA es comparable al de mezclas calientes convencionales. Dicha conclusión puede aportar confianza a este tipo de mezclas sostenibles promoviendo su mayor utilización

    Evaluación cualitativa del programa comunitario Irunsasoi para la promoción de la actividad física: la perspectiva de los médicos

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    Objectives: The sedentarism is an important conditioner of morbidity and mortality. The communitarian programs of promotion of physical activity that include a pursuit protocol can help and complement to the medical advice in the consultation. The objectives that we marked ourselves with this study have been to know the opinion the doctors on the prescription of physical activity and the implantation of the Irunsasoi program, collaboration between the doctors of Primary Attention and the technicians of physical activity of the council of Irún City to help the sedentary people. Methodology Design: Technique of focal groups. The discussions were recorded and later transcribed, previous authorization, for their analysis. Location: Primary attention. Irún Centro health Center. Subjects: The study population was the 15 doctors of AP. Two groups of 5 doctors, homogenous were made in age and sex, the recruitment was made, the invitation at random to participate was verbal by the investigator without no refusal took place. Measures: The discussion lines were grouped in: attitude before the advice and participation in the program, difficulties of collaboration and proposals of improvement. Results: Positive evaluation of the program to have enabled personnel, sufficient time and guarantees of pursuit. The collaboration difficulties are based on the forgetfulness not to have it built-in to our mechanics of work and to wort in other activities by lack of time. Conclusions: He is positive to work jointly with the technicians of physical activity. Aspects to improve: the formation in prescription of physical activity, the implication of nurses, the circuit of communication and the support in computerized historyObjetivos: El sedentarismo es un importante condicionante de morbilidad y mortalidad. Los programas comunitarios de promoción de actividad física que incluyan un protocolo de seguimiento pueden ayudar y complementar al consejo médico en la consulta. Los objetivos que nos marcamos con este estudio han sido conocer la opinión de los médicos sobre la prescripción de actividad física y sobre la implantación del programa Irunsasoi, de colaboración entre los médicos de Atención Primaria y los técnicos de actividad física del Ayuntamiento de Irún para ayudar a las personas sedentarias. Metodología: Diseño: Técnica de grupos focales. Las discusiones fueron grabadas y posteriormente transcritas, previa autorización, para su análisis. Emplazamiento: Atención primaria. Centro de salud Irún Centro. Sujetos: La población de estudio fueron los 15 médicos de AP. Se realizaron dos grupos de 5 médicos, homogéneos en edad y sexo, el reclutamiento se realizó al azar, la invitación a participar fue verbal por el investigador sin que se produjera ninguna negativa. Medidas: Los ejes de discusión se agruparon en: actitud ante el consejo y participación en el programa, dificultades de colaboración y propuestas de mejora. Resultados: Valoración positiva del programa por disponer de personal capacitado, tiempo suficiente y garantías de seguimiento. Las dificultades de colaboración se basan en el olvido por no tenerlo incorporado a nuestra mecánica de trabajo y priorización de otras actividades por falta de tiempo. Conclusiones: Es positivo trabajar conjuntamente con los técnicos de actividad física. Aspectos a mejorar: la formación en prescripción de actividad física, la implicación de enfermería, el circuito de comunicación y el soporte en la historia informatizad
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