Relaxation oscillations, pulses, and travelling waves in the diffusive Volterra delay-differential equation

The diffusive Volterra equation with discrete or continuous delay is studied in the limit of long delays using matched asymptotic expansions. In the case of continuous delay, the procedure was explicitly carried out for general normalized kernels of the form Sigma/sub n=p//sup N/ g/sub n/(t/sup n//T/sup n+1/)e/sup -t/T/, pges2, in the limit in which the strength of the delayed regulation is much greater than that of the instantaneous one, and also for g/sub n/=delta/sub n2/ and any strength ratio. Solutions include homogeneous relaxation oscillations and travelling waves such as pulses, periodic wavetrains, pacemakers and leading centers, so that the diffusive Volterra equation presents the main features of excitable media

Caracterización estática productiva de las unidades piscícolas en la provincia de Tungurahua

En la provincia de Tungurahua se realizó la caracterización de 162 unidades piscícolas distribuidas en los diferentes cantones, mediante una encuesta se enfoca el aspecto social y productivo, donde se identificó y caracterizó los componentes agroecológicos, agro ecosistemas, los cuales fueron analizados estadísticamente con medidas de tendencia central y de dispersión. Los resultados permitieron identificar la producción de peces en las unidades piscícolas, estando asociadas a características de abastecimiento de agua e infraestructura. Baños se destacó con el 59% del total provincial de siembra de trucha (185430), la mortalidad promedio de 5,36% y se cosechó 44063 kg en total, en un periodo de 6,43 meses, con un caudal de 30,85 lt/seg que proviene de vertientes y ríos, con respecto a tilapia hubo un 31% de siembra del total provincial con 11750 peces, la mortalidad promedio de 5,40% y se cosechó 5067,78 kg en un periodo de 7,20 meses, con un caudal de 1,8 lt/seg provenientes en su totalidad de vertientes.This study took place in Tungurahua province where it was conducted a characterization to 162 fish farms distributed in the different cantons, by means of a survey, it was possible to focus on the social and productive aspects where the agro-ecological components as well as the agro ecosystems, were identified and characterized to be statistically analyzed under measures of central tendency and dispersion. The findings made possible to identify the fish production of the fish ponds being associated to characteristics of water supply and infrastructure. Baños canton stood out with 59% of the provincial total of trout breeding (185430), the average mortality reaches 5,36% and an overall of 44063 kg was harvested in a period of 6,43 months, into a water flow coming from rivers and watersheds that reaches 30,85 l/sec. Regarding to tilapia; there was a 31% of breeding from the provincial total with 11750 fish, the average mortality is 5,40% and 5067,78 kg were harvested in a period of 7,20 months, at a water flow rate of 1,8 l/sec coming entirely from watersheds. Regarding to the agro-ecological characterization, based on the social component; the findings research; show that a number of 123 families make a living from fish farming, from these; 55% correspond to men and 45% to women, the parameter regarding to the educational level demonstrated that 53% of them completed primary school where as a 34% completed secondary school as the most relevant. The manual for fish production is submitted according to the productive and health parameters thus, it is recommended to implement the development strategies by promoting fish culture by means of intensive systems and optimizing resources, in order to meet the market demand of the Tungurahua region

Caracterización estática productiva de las unidades piscícolas en la provincia de Tungurahua

En la provincia de Tungurahua se realizó la caracterización de 162 unidades piscícolas distribuidas en los diferentes cantones, mediante una encuesta se enfoca el aspecto social y productivo, donde se identificó y caracterizó los componentes agroecológicos, agro ecosistemas, los cuales fueron analizados estadísticamente con medidas de tendencia central y de dispersión. Los resultados permitieron identificar la producción de peces en las unidades piscícolas, estando asociadas a características de abastecimiento de agua e infraestructura. Baños se destacó con el 59% del total provincial de siembra de trucha (185430), la mortalidad promedio de 5,36% y se cosechó 44063 kg en total, en un periodo de 6,43 meses, con un caudal de 30,85 lt/seg que proviene de vertientes y ríos, con respecto a tilapia hubo un 31% de siembra del total provincial con 11750 peces, la mortalidad promedio de 5,40% y se cosechó 5067,78 kg en un periodo de 7,20 meses, con un caudal de 1,8 lt/seg provenientes en su totalidad de vertientes. En la caracterización agroecológica en su componente social, el número de familias beneficiadas de la actividad piscícola fue de 123, las cuales el 55% son hombres y 45% mujeres, el parámetro nivel educativo se obtuvo que el 53% presenta estudios de primaria seguido del 34% de secundaria como los más relevantes. Se establece el manual piscícola en función a los parámetros productivos y sanitarios. Por cual se recomienda implementar las estrategias de desarrollo, promoviendo la siembra con sistemas intensivos y optimizando los recursos, con la finalidad de cubrir la demanda del mercado tungurahuense.This study took place in Tungurahua province where it was conducted a characterization to 162 fish farms distributed in the different cantons, by means of a survey, it was possible to focus on the social and productive aspects where the agro-ecological components as well as the agro ecosystems, were identified and characterized to be statistically analyzed under measures of central tendency and dispersion. The findings made possible to identify the fish production of the fish ponds being associated to characteristics of water supply and infrastructure. Baños canton stood out with 59% of the provincial total of trout breeding (185430), the average mortality reaches 5,36% and an overall of 44063 kg was harvested in a period of 6,43 months, into a water flow coming from rivers and watersheds that reaches 30,85 l/sec. Regarding to tilapia; there was a 31% of breeding from the provincial total with 11750 fish, the average mortality is 5,40% and 5067,78 kg were harvested in a period of 7,20 months, at a water flow rate of 1,8 l/sec coming entirely from watersheds. Regarding to the agro-ecological characterization, based on the social component; the findings research; show that a number of 123 families make a living from fish farming, from these; 55% correspond to men and 45% to women, the parameter regarding to the educational level demonstrated that 53% of them completed primary school where as a 34% completed secondary school as the most relevant. The manual for fish production is submitted according to the productive and health parameters thus, it is recommended to implement the development strategies by promoting fish culture by means of intensive systems and optimizing resources, in order to meet the market demand of the Tungurahua region

Evaluación de un sistema de control fotovoltaíco basado en los índices de irradiación solar del Sector Huachi Grande para la automatización de un sistema de regadío.

El presente trabajo de titulación evalúa un Sistema de control fotovoltaico basado en los índices de irradiación solar, del sector Huachi Grande barrio “Nueva Vida”, para la automatización de un sistema de regadío que está basado en la metodología científica, analítica y de síntesis.Se realizó el análisis del historial meteorológico proporcionado por el INAMHI, referente a la estación de Querochaca del cantón Cevallos (Huachi Grande) de la provincia de Tungurahua, los datos analizados corresponden a los años 2016 y 2017 y los mismos son de radiación solar, humedad, temperatura, horas sol, entre otros. Con los datos adquiridos se aplica el método de cálculo de dimensionamiento de estaciones fotovoltaicas, obteniendo valores cuantitativos de insolación solar (2,7KW/m 2 /día), latitud y longitud (-1.3190, -78.6419) respectivamente, del sector de Huachi Grande Barrio Nueva Vida; con lo que dimensiona 1320Watios de consumo y se calcula el número de paneles solares, inversor, regulador y baterías que se necesitan para poner en funcionamiento la bomba de agua, a fin de irrigar un área de 500 m² de terreno. Las pruebas realizadas en el sistema ya implementado, permite analizar los datos de voltajes de los paneles solares en diferentes ángulos de inclinación, concluyendo que el mejor aprovechamiento del sistema se logra con una inclinación de 11.31 xvi 0 con respecto a la horizontal y mirando hacia el norte magnético. El sistema esta dimensionado y diseñado para trabajar 2 días a la semana, durante 3 horas continúas bombeando agua del tanque reservorio al terreno, además cuenta con 3 horas de reserva de energía en sus baterías. La zona de Huachi Grande es óptima para la implementación de sistemas fotovoltaicos, por la irradiación presente en este sector, esta característica hace que los sistemas fotovoltaicos sean una solución viable y ecológica, generando energía renovable con una alta eficiencia, con costos moderados de instalación, reduciendo el impacto ambiental; tomando en considerando que el proyecto tiene visión social, debido a que la zona se encuentra habitada en su mayoría por comunidades de escasos recursos y su población se dedica a la ganadería y agricultura, especialmente al cultivo de frutas.This research work evaluates a photovoltaic control system based on the solar irradiation rates of Huachi Grande neighborhood “Nueva Vida”, for the automation of an irrigation system that is based on scientific, analytical and synthesis methodology. The analysis of the meteorological history provides by the INAMHI was made, referring to Querochaca station of Cevallos (Huachi Grande) canton of Tungurahua province, the analyzed data correspond to the years 2016 and 2017 and they are of solar radiation, humidity, temperature, sun hours, among others. With the acquired data, the calculation method for dimensioning the photovoltaic stations is applied, obtaining the quantitative values of solar insolation (2,7KW/m xvii 2 /day), latitude and longitude (-1.3190 -78.6419) respectively, of Huachi Grande sector, Nueva Vida Neighborhood: which measures 1320 Watios of consumption and calculates the number of solar panels, inverter, regulator and batteries needed to start the water pump, in order to irrigate an area of 500 m 2 of land. The test carried out in the system already implemented, allow analyzing the data of voltages of the solar panels at different angles of inclination, concluding that the best use of the system is achieved with an inclination of 11,31 0 with respect to the horizontal and looking towards the magnetic north. The system is dimensioning and designed to work 2 days a week, for 3 hours continuously pumping water from the reservoir tank to the land. Also it has 3 hours of energy reserve in its batteries. Huachi Grande area is optimal for the implementation of photovoltaic system,by the irradiation present in this sector, this feature makes photovoltaic systems a viable and ecological solution, generating renewable energy with high efficiency, with moderate installation costs, reducing the environmental impact; taking into account that the project has a social vision, due to the area is mostly inhabited by low-income communities and its population is dedicated to livestock and agriculture, especially the cultivation of fruits

La Matemtica Aplicada: entre lo divino y lo humano

España es la décima potencia mundial si consideramos el número de artículos de Matemáticas publicados en un año con un autor español por lo menos .Cuando estos artículos se ponderan con su índice de impacto y se toma la media mundial como cero, el índice español en Matemáticas es 13 . Esta situación es particularmente grave en el área de Matemática Aplicada. Según el informe Andradas-Zuazua (que expurgó los artículos matemáticos aparecidos en revistas relevantes de Física, Mecánica de Medios Continuos, Mecánica de Fluidos, etc. e incluso en la revista SIAM Journal on Applied Mathematics), la revista en que más publican los "matemáticos aplicados" españoles es Proceedings of the American Mathematical Society, una revista que se encuentra año tras año en el último cuarto de la lista de Matemática Aplicada del índice de impacto JCR. Anecdóticamente, la ANECA reconoce esta situación usando baremos más bajos para Matemáticas que para las otras disciplinas científicas

Comentario sobre la Matemática Aplicada en España

En el número de Septiembre de 2004 del Boletín del SEMA, los autores publicamos un artículo de opinión sobre la situación de la Matemática Aplicada en España. El objetivo principal del artículo fue mover a la reflexión sobre algunas deficiencias no corregidas y, en algún caso, aumentadas durante los últimos años. Tales deficiencias pueden hipotecar el futuro de la Matemática Aplicada española, e impedir que contribuya de modo eficaz al desarrollo científico y tecnológico del país

Inertial behavior of offshore devices

Peer Reviewe

Diatomeas epilíticas (Bacillariophyceae) de los cursos de agua corriente del NO de la península ibérica (Galicia, España)

A catalog of Bacillariophyceae for the rivers of NW of Spain is made for the first time. It includes a re-examination of the taxa reported in previous publications, taxa cited during the last years of the rivers of the Galicia-Costa Hydrographic Demarcation, and a revision of the taxonomy, in line with the systematic and nomenclature changes, which have occurred mainly in recent years. The epilethic diatoms of the river basins of Galicia-Costa were sampled during the years 2005, 2006, and 2007, in May-June and September. The study was carried out in 41 localities distributed along 31 rivers, samples were taken in upstream and downstream sections. Diatom communities were compared in all upstream sections of these rivers draining from siliceous substrates. We identified 141 taxa of diatoms from the coast of Galicia. In this paper we present 15 new citations for Galicia, two for Spain and three for the Iberian Peninsula, in addition to a new species recently described. The dominant taxa are: Achnanthidium minutissimum, Achnanthes subhudsonis, Karayevia oblongella, Cocconeis placentula var. euglypta, Gomphonema rhombicum, and Navicula minima. Achnanthes subhudsonis was the most abundant species during the spring and summer months. The remaining species showed no relevant changes regardless of the time of year. The results indicate that the river diatoms of Galicia are an important component of the diversity of the ecosystemSe realiza por primera vez un catálogo de Bacillariophyceae para los ríos del NW de España. Se incluyen un nuevo examen de los táxones recogidos en publicaciones anteriores, datos de táxones citados durante los últimos años de los ríos de la demarcación hidrográfica de Galicia-Costa y una revisión de la taxonomía, en consonancia con los cambios sistemáticos y nomenclaturales, que se han producido sobre todo durante los últimos años. Se estudiaron las diatomeas epilíticas de las cuencas de los ríos de Galicia-Costa entre los años 2005, 2006 y 2007, durante dos temporadas diferentes: mayojunio y septiembre. El estudio se llevó a cabo en 41 localidades distribuidas a lo largo de 31 ríos, donde se tomaron muestras en tramos aguas arriba y aguas abajo. Las comunidades de diatomeas de estos ríos que drenan de sustratos silíceos fueron comparadas en todos los tramos de aguas arriba. Se identificaron 141 táxones de diatomeas de la costa de Galicia. En este trabajo presentamos 15 nuevas citas para Galicia, dos para España y tres para la Península Ibérica, además de una nueva especie recientemente descrita. Los táxones dominantes son: Achnanthidium minutissimum, Achnanthes subhudsonis, Karayevia oblongella, Cocconeis placentula var. euglypta, Gomphonema rhombicum, y Navicula minima. Achnanthes subhudsonis fue la especie más abundante durante los meses de primavera y verano. Las especies restantes no mostraron cambios pertinentes independientemente de la época del año. Los resultados indican que las diatomeas de los ríos de Galicia son un componente importante de la diversidad del ecosistemaThe financial support for this work has been provided by Augas de Galicia (Xunta de Galicia) through a contract with the University of Santiago de Compostela for the assessment of the stream water quality in rivers of Galicia-Costa using diatom metrics (2005—2007). We are indebted to Juan Manuel Antelo Cortizas (Department of Química-Física) and Teresa García Bernadal (researcher of Santiago de Compostela University) for their assistance during fieldwork and insightful comments on stream chemistry and ecologyS

A multi-agent system for managing adverse weather situations on the road network

The development of traffic management and control strategies to improve traffic flows and road safety is necessary due to the high dynamism of traffic flows. The use of distributed intelligent systems can help the traffic organizations and the road operators to cope with possible incidents on the road network, especially when the incidents are related to adverse meteorological conditions. In that case, the probability of road accidents is increased due to the difficulty of driving under bad weather conditions. So, if the operators detect any meteorological incident, they must decide how to deal with it in order to improve traffic safety. In this paper we introduce a new multiagent system (MAS) to support traffic management when there appear meteorological problems in the road network. MAS technology helps to deal with the specific characteristics of traffic domain. The proposed MAS is able to work in two ways: a) coordinately, where all the agents work to solve weather problems in large networks and b) locally, where due to communications breakdown small groups of agents work together to inform road users about weather problems. The MAS has a rule-based system to deal with the meteorological data and decide the actions to take in front of any meteorological issue. This expert system also controls the quality of the data, improving the road operator confidence in the decisions taken by the expert system. However, weather sensors can provide wrong data, due to several factors (hardware failure, climate factors, etc.) so the rule based system controls these provided data by applying specific coherence and correlation rules to improve the quality of the taken decisions

Force sensor of a climbing robot derived from its own flexible structure

One of the most important design constraints of a climbing robot is its own weight. When links or legs are used as a locomotion system they tend to be composed of special lightweight materials, or four-bars-linkage mechanisms are designed to reduce the weight with small rigidity looses. In these cases, flexibility appears and undesirable effects, such as dynamics vibrations, must be avoided at least when the robot moves at low speeds. The knowledge of the real tip position requires the computation of its compliance or stiffness matrix and the external forces applied to the structure. Gravitational forces can be estimated, but external tip forces need to be measured. This paper proposes a strain gauge system which achieves the following tasks: (i) measurement of the external tip forces, and (ii) estimation of the real tip position (including flexibility effects). The main advantages of the proposed system are: (a) the use of external force sensors is avoided, and (b) a substantial reduction of the robot weight is achieved in comparison with other external force measurement systems. The proposed method is applied to a real symmetric climbing robot and experimental results are presented