2,626 research outputs found

    Estudio comparativo de equipos fijos de pedestal y su aplicación en la detección del tráfico incontrolado de material radiactivo en aeropuertos

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    En este trabajo se analiza la respuesta de tres equipos comerciales, diseñados para detectar el tráfico ilícito o el desplazamiento involuntario de material radiactivo en aeropuertos cuando es transportado por los pasajeros. Se han comparado tres instrumentos fijos de pedestal: el equipo APM de Bicron, el equipo GR-606 de Exploranium y el equipo FHT-1372 de Thermo Eberline. En esta evaluación inicial, realizada en el Laboratorio de Ingeniería Nuclear de la Escuela de Caminos, Canales y Puertos, se observó que el equipo FHT-1372 presentó una respuesta de detección más rápida, sensible y permitió la medida de tasa de dosis total y tasa de dosis artificial. Este equipo fue instalado en la salida de la aduana de pasajeros del aeropuerto internacional de Barajas durante un periodo operativo de 108 días en el año 2002 y pasaron un total de 1.339.931 personas. Este periodo se dividió en 5 sesiones para poder establecer los niveles de investigación adecuados para detectar una posible incidencia de material radiactivo, que finalmente se fijaron en 110 nSv/h para la tasa de dosis total y 25 nSv/h para la tasa de dosis artificial. Durante dicho periodo se detectaron 39 posibles incidencias por encima del límite de investigación establecido para las diferentes sesiones, 5 de ellas con un valor 10 veces superior al fondo ambiental de la sala donde se instaló el equipo (alrededor de 90 nSv/h) y ninguna superó el nivel de 100 μSv/h a 1 m de distancia que la Organización Internacional de la Energía Atómica (OIEA) establece como límite para el transporte lícito de material radiactivo

    Lack of association of a variable number of aspartic acid residues in the asporin gene with osteoarthritis susceptibility: case-control studies in Spanish Caucasians

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    A recent genetic association study has identified a microsatellite in the coding sequence of the asporin gene as a susceptibility factor for osteoarthritis (OA). Alleles of this microsatellite determine the variable number of aspartic acid residues in the amino-terminal end of the asporin protein. Asporin binds directly to the growth factor transforming growth factor beta and inhibits its anabolic effects in cartilage, which include stimulation of collagen and aggrecan synthesis. The OA-associated allele, with 14 aspartic acid residues, inhibits the anabolic effects of transforming growth factor beta more strongly than other asporin alleles, leading to increased OA liability. We have explored whether the association found in several cohorts of Japanese hip OA and knee OA patients was also present in Spanish Caucasians. We studied patients that had undergone total joint replacement for primary OA in the hip (n = 303) or the knee (n = 188) and patients with hand OA (n = 233), and we compared their results with controls (n = 294) lacking overt OA clinical symptoms. No significant differences were observed in any of the multiple comparisons performed, which included global tests of allele frequency distributions and specific comparisons as well as stratification by affected joint and by sex. Our results, together with reports from the United Kingdom and Greece, indicate that the stretch of aspartic acid residues in asporin is not an important factor in OA susceptibility among European Caucasians. It remains possible that lifestyle, environmental or genetic differences allow for an important effect of asporin variants in other ethnic groups as has been reported in the Japanese, but this should be supported by additional studies

    Método experimental para identificar el nivel de atención en las personas

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    The student’s level of attention in the school environment is related to different physiological variables of the body. The study of physiological signals related to attention such as brain waves, heart rate, breathing rate, sweat, sight tracking, among others, has revealed significant advances in recent times. This work presents the development of a system to measure the level of attention in real-time and quantitatively. The sensed variables to determine the user’s level of attention are Beta-type brain waves and two angles that describe the student’s corporal posture. The mathematical analysis describes the process to obtain the correlation between the percentages of the brain waves with the angles from the corporal posture. The resultant coefficient of correlation is in a considerable correlation interval. It denotes that the corporal posture can be considered a parameter that influences students’ level of attention.El nivel de atención de un estudiante en su entorno escolar está relacionado con diferentes variables fisiológicas del cuerpo humano. El estudio de las señales fisiológicas relacionadas con el nivel de atención como ondas cerebrales, frecuencia cardíaca, entre otros, ha revelado grandes avances en los últimos tiempos. En este trabajo se presenta el desarrollo de un sistema para medir la atención en tiempo real y de forma cuantitativa. Las variables sensadas para poder determinar el nivel de atención del usuario son: Las ondas cerebrales tipo beta y dos ángulos que describen la postura corporal del estudiante. Se busca la correlación el porcentaje de atención que se obtiene de las ondas cerebrales, con los ángulos obtenidos de la postura corporal a través de un análisis matemático. El coeficiente de correlación resultante denota que la postura corporal puede considerarse como un parámetro que influye en el nivel de atención de los estudiantes

    Fragmentación primaria en la combustión en lecho fluidizado de pellets de serrín

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    Parece ser que La combustión en lecho fluidizado tiene buenas perspectivas dentro de las opciones tecnológicas para la generación de energía a partir de un combustible, dada su flexibilidad respecto a los combustibles a emplear como sus posibilidades de operación limpia y eficiente, junto a la posibilidad de cambio de escala. En este artículo se exponen los resultados alcanzados a escala de planta piloto en el funcionamiento de un reactor de lecho fluidizado en la combustión de pellets de serrín con vistas a su aplicación en el aprovechamiento de los residuos sólidos en el proceso de producción de bioetanol de lignocelulósicos

    Cis-regulation of IRF5 expression is unable to fully account for systemic lupus erythematosus association: analysis of multiple experiments with lymphoblastoid cell lines

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    INTRODUCTION: Interferon regulatory factor 5 gene (IRF5) polymorphisms are strongly associated with several diseases, including systemic lupus erythematosus (SLE). The association includes risk and protective components. They could be due to combinations of functional polymorphisms and related to cis-regulation of IRF5 expression, but their mechanisms are still uncertain. We hypothesised that thorough testing of the relationships between IRF5 polymorphisms, expression data from multiple experiments and SLE-associated haplotypes might provide useful new information. METHODS: Expression data from four published microarray hybridisation experiments with lymphoblastoid cell lines (57 to 181 cell lines) were retrieved. Genotypes of 109 IRF5 polymorphisms, including four known functional polymorphisms, were considered. The best linear regression models accounting for the IRF5 expression data were selected by using a forward entry procedure. SLE-associated IRF5 haplotypes were correlated with the expression data and with the best cis-regulatory models. RESULTS: A large fraction of variability in IRF5 expression was accounted for by linear regression models with IRF5 polymorphisms, but at a different level in each expression data set. Also, the best models from each expression data set were different, although there was overlap between them. The SNP introducing an early polyadenylation signal, rs10954213, was included in the best models for two of the expression data sets and in good models for the other two data sets. The SLE risk haplotype was associated with high IRF5 expression in the four expression data sets. However, there was also a trend towards high IRF5 expression with some protective and neutral haplotypes, and the protective haplotypes were not associated with IRF5 expression. As a consequence, correlation between the cis-regulatory best models and SLE-associated haplotypes, regarding either the risk or protective component, was poor. CONCLUSIONS: Our analysis indicates that although the SLE risk haplotype of IRF5 is associated with high expression of the gene, cis-regulation of IRF5 expression is not enough to fully account for IRF5 association with SLE susceptibility, which indicates the need to identify additional functional changes in this gene

    Red Neuronal Profunda (RNP) Aplicada al Análisis de Deserción Estudiantil en una Institución de Educación Superior

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    This paper reports the design of a deep neural network (DNN) focused to predict patterns of student dropout at the UPTC University of Colombia. We apply specialized artificial intelligence (AI) algorithms for the implementation of the DNN specifically were using a learning machine for classification and clustering task. Additionally, a dataset containing 17 attributes of 3000 academically active students was structured; the data set has been prepared to be trained as an entry to the neural network. The final result of the research reveals a predictive model trained through the DNN validated by several quality metrics that demonstrate reliability and accuracy of the results accomplished through the model.Objetivo: Presentar el diseño de una red neuronal profunda (DNN) enfocada a predecir patrones de deserción estudiantil en la Universidad UPTC de Colombia. Metodología: Aplicamos algoritmos especializados de inteligencia artificial (IA) para la implementación de la DNN específicamente utilizando una máquina de aprendizaje para tareas de clasificación y agrupación. Adicionalmente, se estructuró un dataset que contiene 17 atributos de 3000 estudiantes académicamente activos; el conjunto de datos ha sido preparado para ser entrenado como una entrada a la red neuronal. Resultados: En la investigación se analiza un modelo predictivo entrenado a través de la DNN validado por varias métricas de calidad que demuestran la confiabilidad y precisión de los resultados logrados a través del modelo. Conclusiones: Hemos centrado nuestro estudio en la aplicación de la arquitectura de redes neuronales para abordar este problema de abandono. Nuestro modelo logra no solo una alta precisión, sino también una baja tasa de falsos negativos mientras predice abandonos en el conjunto de datos recopilados

    Polymeric pigments formed in sequential fermentation of red fresh musts by adding flavan-3-ols

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    Red wine pigments are susceptible to degradation by light, SO2 and changes in pH and temperature1,2. The formation of pyranoanthocyanins and polymeric pigments during fermentation and wine aging promote the stability of such pigments3. Glycolytic metabolites (e.g. acetaldehyde and pyruvic acid) may interact with anthocyanins and flavan-3-ols to form more stable molecules4 without a drastic change in hue values. Procyanidins are molecules from the flavanoids family that may condense with anthocyanins5. The contribution of non-Saccharomyces yeasts (e.g. L. thermotolerans, M. pulcherrima and T. delbrueckii), in sequential fermentation with S. cerevisiae and S. pombe, to the production of stable pigments was assessed in this project. with the use of HPLC-DAD/MS-ESI. The red musts have been enriched with flavanols prior fermentation. Fermentative volatiles and sensorial analysis were also performed to characterize experimental wines produced

    Heterogeneous Photocatalytic Degradation of Ibuprofen Over TiO2–Ag Supported on Activated Carbon from Waste Tire Rubber

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    In recent years it has been discovered that some common use medicines, such as ibuprofen and other nonsteroidal anti-inflammatory drugs, are found in water sources in concentrations that have the potential to affect aquatic organisms. On the other hand, waste used tires are a massive problem for the environment due to the leaching of toxic compounds to soils and water. Also, the exposition to environmental conditions can make them sources of vectors like mosquitoes. In this work, three activated carbon (AC) catalysts derived from waste tire rubber, titanium dioxide and silver were synthesized using the sol–gel method. Morphological characterizations such as SEM and TEM were performed in which, the agglomeration of titanium particles and silver crystals on the surface of the AC is evident. In the XRD analysis, the presence of elemental silver nanoparticles was detected. In the diffuse reflectance spectroscopy analysis, the decrease in the titanium band gap, as well as activity in the visible spectrum, was observed. The photocatalytic tests were performed at pH 3 and 7 in the presence of UV/Vis radiation. These tests show that there are differences between the catalyst in both, UV and visible regions. Adsorption is a major phenomenon for the removal of ibuprofen, followed by photolytic decomposition. In visible spectra, the catalysts show a good performance for the removal of ibuprofen

    Effect of Steel Fibre Reinforcement on Flexural Fatigue Behaviour of Notched Structural Concrete

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    ABSTARCT: One of the biggest challenges in facilitating the installation of concrete is the development of fibre-reinforced concrete. Although nowadays fibre reinforced concrete is relatively common, it is still necessary to deepen in the study on its behaviour, especially regarding its fatigue behaviour. This paper proposes a new methodology to analyse the bending fatigue behaviour of notched test specimens. From these tests, it was possible to verify that, despite carrying out the tests with load control, the presence of fibres extends the fatigue life of the concrete after cracking. This effect is of great importance since during the extra lifetime with the cracked concrete, the damage to the concrete will be evident and the corresponding maintenance measures can be carried out. Regarding the analysis of the results, in addition to obtaining a traditional S-N curve, two new criteria have been applied, namely energy and notch growth. From these two new approaches, it was possible to determine critical energy values that can be used as predictive indicators of the collapse of the element. Moreover, from the notch growth analysis, it was possible to determine crack growth rate as a function of the stress conditions for the concrete and the specific geometry. From the comparison among the results obtained from the different tests, a limit cracking index of 0.05 mm can be defined
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