290 research outputs found

    Highly tunable optically switched time delay line for transversal filtering

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    A novel tunable dispersion device, based on two chirped fibre gratings subjected to non-uniform magnetic fields, is presented. A large degree of tunability is achieved from 250 to 750 ps/nm. This is used to demonstrate RF filtering in the 3-11 GHz range

    Band selection pipeline for maturity stage classification in bell peppers: From full spectrum to simulated camera data

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    This paper describes a workflow for classifying the maturity of bell peppers using hyperspectral imaging and machine learning. The approach involves using spectral reflectance to determine the number of maturity stages, followed by a classification task using the optimal bands for accurate classification. The study explores a realistic scenario using simulated camera responses and investigates the use of real sensors with their spectral sensitivities and noise. Four classifier algorithms (RBFNN, PLS-DA, SVM, and LDA) were employed to predict the maturity stage based on spectral reflectance. The best results were achieved with the LDA algorithm, which was used in the optimization process for band selection. The optimized bands in the VISNIR range (400–1000 nm) were found to be [783.5, 844.1, and 905.4] nm, with an accuracy of 90.67% for spectral data. For camera responses with intermediate-level noise, the best bands were [760, 820, and 900 nm], achieving an accuracy of 81%. Overall, using three bands yielded satisfactory and practical results for real-world implementation.Universidad de Granada/CBU

    Four-channel self-compensating single-slope ADC for space environments

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    A multichannel high-resolution single-slope analogue-to-digital converter (SS ADC) is presented that automatically compensates for process, voltage and temperature variations, as well as for radiation effects, in order to be used in extreme environmental conditions. The design combines an efficient implementation by using a feedback loop that ensures an inherently monotonic and very accurate ramp generation, with high levels of configurability in terms of resolution and conversion rate, as well as input voltage range. The SS ADC was designed in a standard 0.35 μm CMOS technology. Experimental measurements of the performance and stability against radiation and temperature are presented to verify the proposed approach

    A Front-End ASIC for a 3-D Magnetometer for Space Applications by Using Anisotropic Magnetoresistors

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    This paper presents an application-specific integrated circuit (ASIC) aimed for an alternative design of a digital 3-D magnetometer for space applications, with a significant reduction in mass and volume while maintaining a high sensitivity. The proposed system uses magnetic field sensors based on anisotropic magnetoresistances and a rad-hard mixed-signal ASIC designed in a standard 0.35 μm CMOS technology. The ASIC performs sensor-signal conditioning and analogue-to-digital conversion, and handles calibration tasks, system configuration, and communication with the outside. The proposed system provides high sensitivity to low magnetic fields, down to 3 nT, while offering a small and reliable solution under extreme environmental conditions in terms of radiation and temperature.Ministerio de Ciencia e Innovación AYA2011-29967-C05-05, AYA2009-14212-C05-04, AYA2008-06420-C04-0

    Collagen XIX Alpha 1 improves prognosis in amyotrophic lateral sclerosis

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    The identification of more reliable diagnostic or prognostic biomarkers in age-related neurodegenerative diseases, such as Amyotrophic Lateral Sclerosis (ALS), is urgently needed. The objective in this study was to identify more reliable prognostic biomarkers of ALS mirroring neurodegeneration that could be of help in clinical trials. A total of 268 participants from three cohorts were included in this study. The muscle and blood cohorts were analyzed in two cross-sectional studies, while the serial blood cohort was analyzed in a longitudinal study at 6-monthly intervals. Fifteen target genes and fourteen proteins involved in muscle physiology and differentiation, metabolic processes and neuromuscular junction dismantlement were studied in the three cohorts. In the muscle biopsy cohort, the risk for a higher mortality in an ALS patient that showed high Collagen type XIX, alpha 1 (COL19A1) protein levels and a fast progression of the disease was 70.5% (P < 0.05), while in the blood cohort, this risk was 20% (P < 0.01). In the serial blood cohort, the linear mixed model analysis showed a significant association between increasing COL19A1 gene levels along disease progression and a faster progression during the follow-up period of 24 months (P < 0.05). Additionally, higher COL19A1 levels and a faster progression increased 17.9% the mortality risk (P < 0.01). We provide new evidence that COL19A1 can be considered a prognostic biomarker that could help the selection of homogeneous groups of patients for upcoming clinical trial and may be pointed out as a promising therapeutic target in ALS

    La Cátedra de Rolando García de humanismo, interdisciplina y complejidad del CEG-UNA

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    Se presenta el proyecto de la Cátedra Rolando García de Humanismo, Interdisciplina y Complejidad (CRG) del Centro de Estudios Generales (CEG) de la Universidad Nacional (UNA), para el período 2015-2020. El objetivo de esta publicación es avanzar en la elaboración de un marco conceptual y metodológico para la implementación práctica del trabajo interdisciplinario en el CEG. Se presentan los antecedentes (marco conceptual preliminar) en los que se fundamenta el objetivo, los alcances y el plan de trabajo de la cátedra, así como las etapas y la metodología de trabajo en equipo conducente a la materialización de una serie de productos que servirán de plataforma de lanzamiento del trabajo interdisciplinario en el CEG. La Cátedra Rolando García de humanismo, interdisciplina y complejidad busca gestar un espacio de investigación, reflexión, debate, producción y extensión, que durante tres años desarrolle las bases conceptuales y metodológicas y una hoja de ruta, para la profundización del Nuevo Humanismo en tanto paradigma transdisciplinario, así como del desarrollo práctico de la interdisciplina en las cuatro áreas de la acción sustantiva principales del quehacer académico de la UNA: docencia, investigación, extensión y producción. Para ello la Cátedra está concebida como un foro abierto, plural y participativo

    Memorias encuentro de investigación en comunicación publicitaria

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    Día a día, como consumidores somos abordados más de 3.000 veces por todo tipo de anuncios publicitarios, de los cuales solo quedan en nuestra cabeza alrededor del 12% (Dinero, 2018). Algunos pensarán que todos esos anuncios que se perciben día a día son fruto de chispazos de un grupo de creativos vinculados al mundo de la publicidad. Sin embargo, la realidad que viven muchas de las personas que pertenecen a este gremio es la de crear una idea y convertirla en una solución que puede llevar desde horas hasta días o meses e incluso años de investigación para ponerla a prueba, saltando obstáculos de presupuesto, efectividad, medios y claramente el gusto del cliente. La publicidad en Colombia se ha venido transformando como parte de la revolución que las industrias creativas han demostrado en los últimos años gracias a sus resultados, y una parte de ello se debe al trabajo que ha realizado desde la academia. En el caso concreto, la Universidad Sergio Arboleda desde la Escuela de Publicidad trabaja diariamente de la mano de profesores que hacen parte de la industria, aplicando los conocimientos aprendidos en talleres y actividades relacionados con mercados locales o internacionales, uso de simulaciones de trabajo con clientes reales bajo un enfoque de planeación estratégica, donde los estudiantes centran su atención en el entorno corporativo, la empresa y sus clientes-consumidores. En línea con lo mencionado y promover el crecimiento de la industria publicitaria, se busca formar profesionales con alta capacidad de investigación y solución de problemas, y como parte de este proceso para la presentación de los resultados finales se organizó el II Encuentro de Investigación en Comunicación Publicitaria, cuyo objetivo se centró en generar espacios de interacción que permitan la disertación del conocimiento científico a través de los procesos de investigación en el aula de clase, así como de las experiencias obtenidas por los estudiantes que asistieron al seminario internacional en Madrid (España). Como resultado final del Encuentro de Investigación se elaboró el presente documento que recopila las memorias con los principales resultados de las diferentes ponencias presentadas por los estudiantes participantes, por lo que a continuación se presentan los trabajos de los estudiantes de Investigación de Mercados, Tendencias, Moda y Estilos de Vida y los Workshop (Madrid- España

    Environmental gradients and the evolution of successional habitat specialization: A test case with 14 Neotropical forest sites

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    https://www.scopus.com/inward/record.url?eid=2-s2.0-84939570316&partnerID=40&md5=fcadae8e6c274e8b7efca96099304a7cSuccessional gradients are ubiquitous in nature, yet few studies have systematically examined the evolutionary origins of taxa that specialize at different successional stages. Here we quantify successional habitat specialization in Neotropical forest trees and evaluate its evolutionary lability along a precipitation gradient. Theoretically, successional habitat specialization should be more evolutionarily conserved in wet forests than in dry forests due to more extreme microenvironmental differentiation between early and late-successional stages in wet forest. We applied a robust multinomial classification model to samples of primary and secondary forest trees from 14 Neotropical lowland forest sites spanning a precipitation gradient from 788 to 4000 mm annual rainfall, identifying species that are old-growth specialists and secondary forest specialists in each site. We constructed phylogenies for the classified taxa at each site and for the entire set of classified taxa and tested whether successional habitat specialization is phylogenetically conserved. We further investigated differences in the functional traits of species specializing in secondary vs. old-growth forest along the precipitation gradient, expecting different trait associations with secondary forest specialists in wet vs. dry forests since water availability is more limiting in dry forests and light availability more limiting in wet forests. Successional habitat specialization is non-randomly distributed in the angiosperm phylogeny, with a tendency towards phylogenetic conservatism overall and a trend towards stronger conservatism in wet forests than in dry forests. However, the specialists come from all the major branches of the angiosperm phylogeny, and very few functional traits showed any consistent relationships with successional habitat specialization in either wet or dry forests. Synthesis. The niche conservatism evident in the habitat specialization of Neotropical trees suggests a role for radiation into different successional habitats in the evolution of species-rich genera, though the diversity of functional traits that lead to success in different successional habitats complicates analyses at the community scale. Examining the distribution of particular lineages with respect to successional gradients may provide more insight into the role of successional habitat specialization in the evolution of species-rich taxa

    Consumo de drogas ilegales, apoyo familiar y factores relacionadosen estudiantes universitarios. Un estudio transversal basado en datosdel Proyecto uniHcos

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    Objective: To assess the prevalence of illegal drug use in college students on any previous occasion, duringthe previous year and the previous month, and to analyze the relationship between illegal drug use andfamily support and other factors.Methods: A cross-sectional study using data from students participating in the uniHcos project (n = 3767)was conducted. The prevalence and age of onset of consumption of cannabis, non-prescription sedatives,stimulants and depressants was evaluated. Polyconsumption was also assessed. The independent vari-ables were: family support, age, residence, and employment status. To determine the factors related todrug use multivariate logistic regression models stratified by gender were fitted.Results: Differences between men and women in prevalence of illegal drug use except non-prescriptionsedatives were observed. In both genders, less family support was associated with higher consumptionof all drugs, except depressants, and with polyconsumption. To be studying and looking for work wasrelated to cannabis and stimulant use and to polyconsumption among women, but only to cannabis useamong men.Conclusions: These results support the notion that the start of university studies is a particularly relevantstage in the onset of illegal drug use and its prevention, and that consumption may be especially associatedwith family support.Objetivo: Evaluar la prevalencia del consumo de drogas ilegales en estudiantes universitarios y analizarla relación entre dicho consumo, el apoyo familiar y otros factores.Método: Se realizó un dise?no transversal basado en datos de participantes en el proyecto uniHcos (n =3767). Se evaluaron la prevalencia y la edad de inicio del consumo de cannabis, tranquilizantes sin receta,estimulantes y depresores, y el policonsumo. Como variables independientes se consideraron el apoyofamiliar, la edad, la residencia y la situación laboral. Para la determinación de los factores asociados alconsumo de drogas se ajustaron modelos de regresión logística estratificados por sexo.Resultados: Se observaron diferencias entre hombres y mujeres en la prevalencia del consumo de todaslas drogas ilegales, excepto tranquilizantes sin receta. En ambos sexos, cuanto peor apoyo familiar, mayorconsumo de todas las drogas, excepto depresores y policonsumo. Encontrarse estudiando y buscandotrabajo se relacionó con el consumo de cannabis, estimulantes y policonsumo en las mujeres, y solo concannabis en los hombres.Conclusiones: Los resultados de este estudio aportan nueva evidencia a favor de que el inicio de la etapauniversitaria es un momento de especial relevancia en el inicio del consumo de drogas ilegales y suprevención, pudiendo este consumo estar especialmente relacionado con el apoyo familiar

    Healthcare workers hospitalized due to COVID-19 have no higher risk of death than general population. Data from the Spanish SEMI-COVID-19 Registry

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    Aim To determine whether healthcare workers (HCW) hospitalized in Spain due to COVID-19 have a worse prognosis than non-healthcare workers (NHCW). Methods Observational cohort study based on the SEMI-COVID-19 Registry, a nationwide registry that collects sociodemographic, clinical, laboratory, and treatment data on patients hospitalised with COVID-19 in Spain. Patients aged 20-65 years were selected. A multivariate logistic regression model was performed to identify factors associated with mortality. Results As of 22 May 2020, 4393 patients were included, of whom 419 (9.5%) were HCW. Median (interquartile range) age of HCW was 52 (15) years and 62.4% were women. Prevalence of comorbidities and severe radiological findings upon admission were less frequent in HCW. There were no difference in need of respiratory support and admission to intensive care unit, but occurrence of sepsis and in-hospital mortality was lower in HCW (1.7% vs. 3.9%; p = 0.024 and 0.7% vs. 4.8%; p<0.001 respectively). Age, male sex and comorbidity, were independently associated with higher in-hospital mortality and healthcare working with lower mortality (OR 0.211, 95%CI 0.067-0.667, p = 0.008). 30-days survival was higher in HCW (0.968 vs. 0.851 p<0.001). Conclusions Hospitalized COVID-19 HCW had fewer comorbidities and a better prognosis than NHCW. Our results suggest that professional exposure to COVID-19 in HCW does not carry more clinical severity nor mortality
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