Volver al Teatro: Costa Rica

Un panorama de las artes escénicas en el ámbito de la lengua castellana, desde Costa Rica. Para volver a algo se infiere que hubo una partida. Algunos juzgan, a partir de su propio alejamiento e imaginario, la validez de regresar a épocas teatrales que les resultaron cómodas; otros, más constantemente activos y actualizados, no piensan en reencuentros sino en continuar la labor escénica, con tesón y sin nostalgia

CFD Modeling and Validation of Blast Furnace Gas/Natural Gas Mixture Combustion in an Experimental Industrial Furnace

The use of residual gases from steel production processes as fuel for steel treatment furnaces has attracted great interest as a method for reducing fossil fuel consumption and the steel footprint. However, these gases often have a low calorific value, and a direct substitution can lead to low temperatures or combustion instability issues. CFD simulations of the combustion of these gases can help steel producers forecast the results of the substitution before real testing and implementation. In this study, a CFD model of an industrial experimental furnace in the steel sector is developed and validated. The results are calculated using the combustion, radiation, and heat transfer models included in the software Ansys Fluent. The validation of the simulated results is performed with data acquired from experimental tests under the same simulated conditions at three air-to-fuel equivalence ratios, which vary from an excess of 0% to an excess of 5% oxygen at the outlet. The model is adjusted to the results, capturing the trends of the measured physical variables and pollutant concentrations. In the case of the combustion temperature, the differences between the simulated and measured values vary from 0.03% to 6.9. Based on the simulation results, the use of blast furnace gas as fuel produces temperatures inside the chamber between 1004 °C and 1075 °C and high stream velocities because of the high flow needed to keep the power constant. Flames exhibit straight movements since the high flows absorb the effect of the swirling flames. The addition of natural gases increases the combustion temperature up to 1211 °C and reduces the flow and length of the flames. Finally, temperatures up to 1298 °C and shorter flames are reached with natural gas enriched with a stream of oxygen, but in this case, NOx emissions need to be controlled

Analysis of the evolution of ultra-filtered water quality in a drinking water distribution system by particle size distribution: Influence of pre-ozonation

An experimental drinking water distribution system (DWDS) was used to evaluate the evolution of particle size distribution (PSD) and basic quality parameters of ultrafiltered water with or without pre-ozonation. An ultrafiltration (UF) module was set up, associated with a pre-ozonation system (3.7 g O3/m3). The permeate was circulated in the DWDS (300 m; 0.9 m/s) with 0.4 mg/L of chlorine, and the analysis of the PSD was performed using a β-variable mathematical model. A better control of membrane fouling was obtained with preozonation, and PSD was necessary to observe water quality differences between permeates and in the DWDS. A decrease in particle concentration of 1.8 logarithms was obtained with the application of UF membranes, while a decrease of only 1.2 logarithms was obtained with pre-ozonation. The system without pre-ozonation showed a higher efficiency at removing smaller particles (around 2 μm), with the absence of particles larger than 23 μm during both stages. The PSD revealed a worsening of water quality in the DWDS with an increase of particles smaller than 5 μm during the application of UF membranes, while with pre-ozonation, all particle sizes analyzed increased their concentration. Practitioner Points • Pre-ozonation led to a better control of membrane fouling, but a worsening of permeate quality according to particle size distribution. • Pre-ozonation does not improve the turbidity, dissolved organic carbon or UV254 removal capacity of ultrafiltration during drinking water treatment. • Particles size distribution reveals the deterioration of water quality in a drinking water distribution system better than turbidity or DOC. • Ozone prior to ultrafiltration membranes led to a worsening of permeate quality, more significant in the drinking water distribution system.Spanish Ministry of Science and Innovation, Grant/Award Number: CTM2010-18899-TECN

Resonant neutrino self-interactions and the H0H_0 tension

In this work, we study the previously unexplored resonant region of neutrino self-interactions. Current disagreement on late and early time observations of the Universe expansion could be solved with new physics acting before the recombination era. Nonstandard neutrino self-interactions are among the most appealing candidates to solve this issue since they could be testable in the near (or midterm) future. We use linear cosmological datasets to test neutrino self-interactions for a sample of fixed scalar mediator masses in the range $10^{-2}$ eV $\leq m_{\varphi}\leq 10^{2}$ eV. The resonant behavior produces observable effects at lower couplings than those reported in the literature for heavy and light mediators. We observe that in the best case scenario, using the Planck + BAO dataset, the tension with local measurements of $H_0$ eases from 4.9$\sigma$ (for $\Lambda$CDM) down to 2.8$\sigma$. Albeit, this is driven mainly by the addition of extra radiation, with $\Delta N_{\rm eff}\sim 0.5$. The joint dataset which includes Planck, BAO, and $H_0$ prefers a nonzero interaction from 2.3$\sigma$ to 3.9$\sigma$ significance in the range $0.5$ eV $\leq m_{\varphi}\leq 10$ eV. Although, this last result is obtained with data that are still in tension. These results add the last piece in the parameter space of neutrino self-interactions at the linear perturbation regime.Comment: Improved discussion and interpretation of results. References added. Matches published versio

Stability and activity of lactate dehydrogenase on biofunctional layers deposited by activated vapour silanization (AVS) and immersion silanization (IS).

The interaction between surfaces and biological elements, in particular, proteins is critical for the performance of biomaterials and biosensors. This interaction can be controlled by modifying the surface in a process known as biofunctionalization. In this work, the enzyme lactate dehydrogenase (LDH) is used to study the stability of the interaction between a functional protein and amine-functionalized surfaces. Two different functionalization procedures were compared: Activated Vapour Silanization (AVS) and Immersion Silanization (IS). Adsorption kinetics is shown to follow the Langmuir model for AVS-functionalized samples, while IS-functionalized samples show a certain instability if immersed in an aqueous medium for several hours. In turn, the enzymatic activity of LDH is preserved for longer times by using glutaraldehyde as crosslinker between the AVS biofunctional surface and the enzyme.pre-print966 K

Análisis del impacto económico y percepción de los usuarios de barranquismo en Extremadura. Un enfoque de género

Adventure tourism has experienced significant growth in recent years and offers benefits to both rural communities and environmental conservation. Therefore, this study aims to characterize the profile, estimated expenditure, perception of economic impact, and satisfaction of adventure tourists visiting Valle del Jerte in Extremadura, Spain, for canyoning activities. Possible differences generated by the gender of tourists on these issues were analyzed. The sample included 673 tourists who practiced canyoning in Valle del Jerte. Statistical tests were used to analyze gender differences in variables such as means of transport used, intention to spend, type of expenditure, and need for public investment. Significant differences were found in the gender of the participants, with men having the highest expenditures. These findings are relevant for public and private organizations as well as for the local community, as they allow them to offer more adequate services to tourists who carry out these activities and attract more visitors.El turismo de aventura ha experimentado un gran crecimiento en los últimos años y ofrece beneficios tanto para las comunidades rurales como para la conservación del entorno, por lo que este trabajo tiene como objetivo caracterizar el perfil, el gasto estimado, la percepción del impacto económico y la satisfacción de los turistas de aventura que visitan el Valle del Jerte en Extremadura, España, para realizar actividades de barranquismo. Se analizan las posibles diferencias generadas por el género del turista en estas cuestiones. La muestra incluyó a 673 turistas que practicaron barranquismo en el Valle del Jerte. Se utilizaron pruebas estadísticas para analizar las diferencias de género en variables como el medio de transporte utilizado, la intención de gasto, el tipo de gasto y la necesidad de inversión pública. Se encontraron diferencias significativas referidas al género de los participantes, siendo los hombres los que más gastos tienen. Estos hallazgos son relevantes para organizaciones públicas y privadas, así como para la comunidad local, ya que les permite ofrecer servicios más adecuados a los turistas que realizan estas actividades y atraer a más visitantes

Sub-Nyquist Wideband Spectrum sensing for Cognitive Radio Networks: Matrix Completion via seed values

Introducción: La Radio Cognitiva (CR) hace un uso eficiente del recurso radioeléctrico, para ello realiza la Detección de Espectro (SS) con el fin de identificar el espectro disponible. Pero debido a la rápida evolución de los transceptores, la microelectrónica y las altas frecuencias de propagación, se hace necesario que en CR se apliquen algoritmos de SS en bandas de frecuencia y se realice un muestreo inferior a la tasa de Nyquist. Objetivo: Adaptar un algoritmo para Detección de Espectro Sub-Nyquist en Banda Ancha (WBSS) para redes de CR mediante la Compleción de Matrices (MC) que integra valores semilla a partir de las muestras conocidas, con el fin de completar las entradas no muestreadas de la banda a evaluar, reconstruir las señales e identificar el espectro disponible. Metodología: Se realizó una adaptación al algoritmo Aproximación Matricial de la Zona de Interés (IZMA), para ello se diseña la etapa de reconstrucción y se elige un método de detección de espectro en banda estrecha para conformar el banco de detectores; el algoritmo que se denomina IZMA_SV es evaluado a nivel de simulación, por tanto se reconstruyen señales determinísticas en diferentes SNR y se identifica el estado del canal como ocupado o libre. Resultados: Las simulaciones indican que el algoritmo adaptado presenta diferencias entre los valores conocidos de la matriz de muestreo M y la matriz recuperada X en SNR inferiores a -8 dB, mientras que la diferencia tiende a cero en SNR superiores a 2 dB. Conclusiones: El algoritmo IZMA-SV logra reducir el número de operaciones para llegar a la matriz aproximada X, reconstruyendo señales muestreadas al 75% de la tasa Nyquist y aún con un muestreo del 20% se mantienen las características de la señal que hacen posible la detección de espectro en banda ancha. Introduction: Cognitive Radio (CR) makes efficient use of the radio resource, for this it performs Spectrum Sensing (SS) in order to identify the available spectrum. But due to the rapid evolution of transceivers, microelectronics and high propagation frequencies, it is necessary for SS algorithms to be applied in frequency bands in CR and for sampling below the Nyquist rate. Objective: Adapt an algorithm for Wideband Sub-Nyquist Spectrum Detection (WBSS) for CR networks using Matrix Completion (MC) integrating seed values from known samples, in order to complete the unsampled inputs of the band to evaluate, reconstruct the signals and the identify the available spectrum. Method: An adaptation to the Interest Zone Matrix Approximation (IZMA) algorithm was carried out, for this purpose the reconstruction stage is designed and a narrow band spectrum sensing method is chosen to form the detector bank; the algorithm called IZMA_SV is evaluated at the simulation level, therefore deterministic signals are reconstructed in different SNRs and the channel status is identified as busy or free. Results: The simulations indicate that the adapted algorithm shows differences between the known values of the sampling matrix M and the recovered matrix X in SNRs lower than -8 dB, while the difference tends to zero in SNRs greater than 2 dB. Conclusions: The IZMA-SV algorithm manages to reduce the number of operations to arrive at the approximate matrix X, reconstructing signals sampled at 75% of the Nyquist rate and even with a sampling of 20% the characteristics of the signal that make possible the detection of wideband spectrum

Detección de espectro en banda ancha Sub-Nyquist para redes Radio Cognitiva: compleción de matrices mediante valores semilla

Introduction: Cognitive Radio (CR) makes efficient use of the radio resource, for this it performs Spectrum Sensing (SS) in order to identify the available spectrum. But due to the rapid evolution of transceivers, microelectronics and high propagation frequencies, it is necessary for SS algorithms to be applied in frequency bands in CR and for sampling below the Nyquist rate. Objective: Adapt an algorithm for Wideband Sub-Nyquist Spectrum Detection (WBSS) for CR networks using Matrix Completion (MC) integrating seed values from known samples, in order to complete the unsampled inputs of the band to evaluate, reconstruct the signals and the identify the available spectrum. Method: An adaptation to the Interest Zone Matrix Approximation (IZMA) algorithm was carried out, for this purpose the reconstruction stage is designed and a narrow band spectrum sensing method is chosen to form the detector bank; the algorithm called IZMA_SV is evaluated at the simulation level, therefore deterministic signals are reconstructed in different SNRs and the channel status is identified as busy or free. Results: The simulations indicate that the adapted algorithm shows differences between the known values of the sampling matrix M and the recovered matrix X in SNRs lower than -8 dB, while the difference tends to zero in SNRs greater than 2 dB. Conclusions: The IZMA-SV algorithm manages to reduce the number of operations to arrive at the approximate matrix X, reconstructing signals sampled at 75% of the Nyquist rate and even with a sampling of 20% the characteristics of the signal that make possible the detection of wideband spectrum.Introducción: La Radio Cognitiva (CR) hace un uso eficiente del recurso radioeléctrico, para ello realiza la Detección de Espectro (SS) con el fin de identificar el espectro disponible. Pero debido a la rápida evolución de los transceptores, la microelectrónica y las altas frecuencias de propagación, se hace necesario que en CR se apliquen algoritmos de SS en bandas de frecuencia y se realice un muestreo inferior a la tasa de Nyquist. Objetivo: Adaptar un algoritmo para Detección de Espectro Sub-Nyquist en Banda Ancha (WBSS) para redes de CR mediante la Compleción de Matrices (MC) que integra valores semilla a partir de las muestras conocidas, con el fin de completar las entradas no muestreadas de la banda a evaluar, reconstruir las señales e identificar el espectro disponible. Metodología: Se realizó una adaptación al algoritmo Aproximación Matricial de la Zona de Interés (IZMA), para ello se diseña la etapa de reconstrucción y se elige un método de detección de espectro en banda estrecha para conformar el banco de detectores; el algoritmo que se denomina IZMA_SV es evaluado a nivel de simulación, por tanto se reconstruyen señales determinísticas en diferentes SNR y se identifica el estado del canal como ocupado o libre. Resultados: Las simulaciones indican que el algoritmo adaptado presenta diferencias entre los valores conocidos de la matriz de muestreo M y la matriz recuperada X en SNR inferiores a -8 dB, mientras que la diferencia tiende a cero en SNR superiores a 2 dB. Conclusiones: El algoritmo IZMA-SV logra reducir el número de operaciones para llegar a la matriz aproximada X, reconstruyendo señales muestreadas al 75% de la tasa Nyquist y aún con un muestreo del 20% se mantienen las características de la señal que hacen posible la detección de espectro en banda ancha.&nbsp

Desarrollo de un sistema de control posicional e interfaz gráfica para el SCORBOT–ER 5PLUS

This article shows how to develop a control system and a graphical interface to the manipulator robot SCORBOT-ER 5plus in the Robotic Laboratory of the Universidad Autónoma del Caribe in order to add an extra tool through which all students can feed in a more practical way in the field of robotics. This will be possible thanks to the use of techniques and concepts of electronics, electricity, control, mechanics and robotics among others, which will help to develop the necessary positional control system, as well as the creation and implementation of a graphical interface to put the robot back into operation in the laboratories of the institution.Este articulo muestra cómo se desarrolla un Sistema de control y una interfaz gráfica para la manipulación de un robot SCORBOT-ER 5plus ubicado en el laboratorio de robótica de la Universidad Autónoma del Caribe con el fin de agregar una herramienta adicional a través de la cual los estudiantes puedan aprender de manera más practica el campo de la robótica. Esto será posible gracias al uso de técnicas y conceptos de electrónica, electricidad, control, mecánica y robótica entre otros, que ayudará a desarrollar el sistema de control posicional necesario, así como la creación e implementación de una interfaz gráfica para poner el robot de nuevo en funcionamiento en los laboratorios de la institución

ZNF330/NOA36 interacts with HSPA1 and HSPA8 and modulates cell cycle and proliferation in response to heat shock in HEK293 cells

Background: The human genome contains nearly 20.000 protein-coding genes, but there are still more than 6,000 proteins poorly characterized. Among them, ZNF330/NOA36 stand out because it is a highly evolutionarily conserved nucleolar zinc-finger protein found in the genome of ancient animal phyla like sponges or cnidarians, up to humans. Firstly described as a human autoantigen, NOA36 is expressed in all tissues and human cell lines, and it has been related to apoptosis in human cells as well as in muscle morphogenesis and hematopoiesis in Drosophila. Nevertheless, further research is required to better understand the roles of this highly conserved protein. Results: Here, we have investigated possible interactors of human ZNF330/NOA36 through affinity-purification mass spectrometry (AP-MS). Among them, NOA36 interaction with HSPA1 and HSPA8 heat shock proteins was disclosed and further validated by co-immunoprecipitation. Also, “Enhancer of Rudimentary Homolog” (ERH), a protein involved in cell cycle regulation, was detected in the AP-MS approach. Furthermore, we developed a NOA36 knockout cell line using CRISPR/Cas9n in HEK293, and we found that the cell cycle profile was modified, and proliferation decreased after heat shock in the knocked-out cells. These differences were not due to a different expression of the HSPs genes detected in the AP-MS after inducing stress. Conclusions: Our results indicate that NOA36 is necessary for proliferation recovery in response to thermal stress to achieve a regular cell cycle profile, likely by interaction with HSPA1 and HSPA8. Further studies would be required to disclose the relevance of NOA36-EHR interaction in this context.14 página