Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Este artículo presenta el diseño de un sistema de energía basado en supercondensadores para mitigar los huecos de tensión, con el sistema se mejora la calidad de energía en el punto de conexión común, el cual está expuesta a la conexión aleatoria de máquinas eléctricas, para ello se modela el sistema de distribución de energía del caso de estudio, el sistema de almacenamiento de energía, que está compuesto por supercondensadores, el sistema de conversión de energía bidireccional y el sistema de control de corriente y voltaje. El sistema diseñado permite inyectar una potencia de 22,8 kW y capacidad de 1,2 Wh, compensando los transitorios producidos por las cargas conectadas a la red.

Native, endemic, and introduced vascular plants from the Galápagos Islands were processed for phytolith extraction. Modern plant specimens of 43 species were collected in the field considering the possible uses of these plant species during the first years of colonization of San Cristóbal Island, Galápagos (1860s). This comparative illustrated catalog is limited to test the production of phytoliths in useful endemic, native, and introduced plant taxa. The results provided the main elements to discriminate morphotypes from native and introduced plants in San Cristóbal. This catalog will guide future paleoethnobotanical research in the Galápagos and other archipelagos of the far eastern pacific islands.

This paper describes design improvement of a current reference, originally based on dual-threshold voltage current mirror stages, these stages have been modified in order to improve the temperature dependence of the current of a diode-connected transistor and the figures of merit to compare this circuit both the base-circuit. The proposed solution has been designed in a 0.18 \text{\ensuremath{\mu}m} technology and analyzed through circuit simulation. Simulation results, when a body-bias generator is used, show an output current of 342 nA and a power consumption below 513 nW at the maximum operating voltage of 1.5 V and at the room temperature. The line sensitivity is 1 %/V, while the temperature coefficient is 17 ppm/°C. On the other hand, when the body-bias generator is neglected, the circuit shows an output current of 188 nA and a power consumption below 282 nW at the maximum operating voltage of 1.5V and at the room temperature. The line sensitivity is 2.89 %/V, while the temperature coefficient is 23 ppm/°C.  Resumen Hoy en día, los espejos de corriente o current reference, pueden ser mejorados con las características de inversión débil subthreshold-region cuando son construidos con tecnología CMOS, está tesis trata sobre cuatro estructuras de current reference basadas en un circuito de solo tres transistores, las figuras de merito como coeficiente de temperatura, consumo de potencia, y sensibilidad de carga y proceso son obtenidas en cada una de las estructuras, y posteriormente son comparadas para disernir cual de las implementaciones ha presentado un mejor desempeño. Las simulaciones fueron realizadas en una tecnología de 180 nm, nanómetros, TSMC CMOS usando transistores de tipo MEDIUM VOLTAGE THRESHOLD (MVT) para un voltaje máximo de alimentación de 2 y 3 voltios. La tesis esta compuesta de cuatro capítulos, el primero muestra los principios físicos para inducir una corriente cuando el transistor MOSFET se encuentra en la región de subthreshold, lineal y saturación. El segundo capitulo muestra las especificaciones tomadas en cuenta para implementar los cuatro diferentes diseños, como son el dimensionamiento y los parámetros eléctricos de las fuentes de alimentación, los diseños fueron implementados en Virtuoso de Cadence. El tercer capitulo muestra los resultados obtenidos en cada uno de los circuitos y una comparativa de las figuras de merito calculadas. Finalmente, el cuarto capitulo muestra las conclusiones de cada bloque, los beneficios obtenidos al implementar cada uno de los diseños así como la mejor solución acorde a las figuras de merito obtenidas. 

En esta investigación se presenta un algoritmo para la autocalibración de los parámetros ex-trínsecos de una cámara estereoscópica mediante el uso de la infraestructura vial y un algoritmometaheurístico, para estimar la altura y los ángulos de cabeceo, balanceo y guiñada. Este algoritmoestá constituido por tres etapas; la primera es la extracción de la información visual de la infraes-tructura vial capturada por el sistema de visión estereoscópica. La segunda etapa es la extensióndel modelo de Collado et al (Collado, Hilario, de la Escalera, y Armingol, 2006), a partir delcual, se obtienen las ecuaciones no lineales que relacionan la altura y los ángulos. Finalmente serealiza la implementación de una metaheurística basada en el algoritmo de optimización colonia de hormigas para solucionar el modelo matemático mundo-cámara usando las líneas de la carretera. Los resultados experimentales muestran la correcta estimación de los cuatro parámetros, obteniéndose un error global del 8% en escenarios de laboratorio y del 9% en escenarios reales de carretera.

This work describes technological possibilities in order to measure the potential energy self-supply capability of cities with urban resources in equatorial Andean cities. From this previous result obtained, the solar has shown the best perspectives. Initially it is described, what real possibilities would exist in Cuenca Ecuador through surveys, according to expert criteria; Five selected alternatives and a complementary sixth (biomass from pruning) are described and a pre-estimation of potential between them is summarized. Then solar source is the one with the greatest potential and with the best adaptability from qualitative aspects, so methodologies applied for the determination of photovoltaic potential are described with the main results found in Cuenca in some typologies that have been advanced, including comparison with temporary demands as well network injection capacity determined in a urban spot. It has been measured that with the technologies analyzed, jointly it can supply over 14% of current urban demands; nevertheless, if a conversion from fuels consumptions are turned toward electrical technologies, the potential increases to 39%.It concludes with the main results obtained and as these reflect that the existing Andean equatorial conditions in Cuenca are advantageous to reach maximum energy standards in buildings.

Corrugated webs are used to increase the shear stability of steel webs of beam-like members and to eliminate the need of transverse stiffeners. Previously developed formulas for predicting the shear strength of trapezoidal corrugated steel webs, along with the corresponding theory, are summarized. An artificial neural network (ANN)-based model is proposed to estimate the shear strength of steel girders with a trapezoidal corrugated web, and under a concentrated load. 210 test results from previous published research were collected into a database according to relevant test specimen parameters in order to feed the simulated ANNs. Seven (geometrical and material) parameters were identified as input variables and the ultimate shear stress at failure was considered the output variable. The proposed ANN-based analytical model yielded maximum and mean relative errors of 0.0% for the 210 points from the database. Moreover, still based on those points, it was illustrated that the ANN-based model clearly outperforms the other existing analytical models, which yield mean errors larger than 13%.

The genus Noctilio includes two species and they occur in elevation ranges that do not exceed 1000 m. They have characteristic eating habits, which is why they are known as fishing bats. Its anatomy and shape of the face, as well as the coloration of the fur makes them very distinctive. In this work we report a record of an adult male of Noctilio leporinus at 3600 m elevation in Migüir locality near Cajas National Park in the Azuay province in the southern Andes of Ecuador. This is the first record for Noctilio leporinus in elevations that exceed 600 meters which makes it an unusual case.

Functional foods are currently in high demand in the market, which is an important challenge for the food industry. Thus, the objective of this work was to develop a functional meat product from inulin, replacing fat and obtaining a prebiotic effect. For this, experiment several combinations of inulin and fat were used: inulin (0 to 12%) and fat (8 to 12%), using potato starch 4% as an ingredient in the formulations. For each sausage physico-chemical composition, texture profile analysis, sensory evaluation and microbiological analyses were carried out. Taking as reference rheological and sensory criteria, the combination with 6,67% inulin and 8,87 % fat proved to be the best variant. The packaging material was characterized and the shelf life was determined for the sausages by studying two different treatments: a vacuum packed, refrigerated product and the other a vacuum packed, re-pasteurized, refrigerated product in both cases maintaining a temperature of 2-4 ° C. The samples were studied at the beginning and the end of the experiment by physicochemical analysis, rheological characterization, throughout the study microbiological analysis and sensory evaluation were carried out. For the study on shelf life, acceptance and rejection criteria were used. The shelf life of the vacuum packed, refrigerated sausages was 26 days, while the vacuum packed, re-pasteurized refrigerated sausages lasted 112 days by risk graph Weibull.

We describe the female of Andinosaura kiziarani from a topotypic locality on the southwestern slope of the Cajas Massif in southern Ecuador. A reduction in transverse dorsal scales, the number of scales between the femoral pores of less than six and an increase in the number of femoral pores distinguish it from the male specimens. In this work we also offer information on the ecological and behavioral characteristics.

Las fintech son un tipo de empresa emergente, emprendimiento o startup que posee modelos de negocio innovadores basados en la tecnología para atender necesidades financieras. En el Perú, las fintech poseen un alto crecimiento debido a la gran cantidad de usuarios insatisfechos por los servicios del sistema financiero tradicional; sin embargo, pese a su acelerado desarrollo, no se encuentran estudios empíricos que aborden el fenómeno del crecimiento en las fintech. Por tanto, este artículo pretende aportar conocimiento, caracterizando los factores internos y externos de crecimiento encontrados en la teoría y comparados en un contexto local. Para ello, se realizó un estudio de casos múltiple con ocho fintech peruanas que pertenecen a los segmentos con mayor crecimiento al 2019 en Lima Metropolitana. Los hallazgos identifican factores clave transversales a la etapa de crecimiento, así como otro grupo en el cual la relevancia sí dependerá de la etapa en la que se encuentren la compañía.