515 research outputs found
Skyrmions, Hadrons and isospin chemical potential
Using the Hamiltonian formulation, in terms of collective variables, we
explore the evolution of different skyrmionic parameters as function of the
isospin chemical potential (), such as the energy density, the charge
density, the isoscalar radius and the isoscalar magnetic radius. We found that
the radii start to grow very fast for MeV, suggesting the
occurrence of a phase transition.Comment: 10 pages, 5 figure
Desarrollo y evaluación de modelos para la toma de decisiones: caracterización de la producción de anguilas (Anguilla anguilla L.) en sistemas intensivos
El objetivo principal de la tesis desarrollada es conseguir una mejora del régimen de explotación en una piscifactoría de anguilas europeas (Anguilla anguilla L.) a través de unas herramientas de predicción y simulación lo suficientemente fiables, que permitan al acuicultor prever a corto y medio plazo los acontecimientos que van a suceder desde un punto de vista patológico, así como a nivel de control de parámetros físicos, químicos y biológicos. De manera global, los principales beneficios que se obtienen de la aplicación del sistema de predicción y simulación son: 1,- Desde el punto de vista patológico, se puede llevar a cabo un diagnóstico precoz de la enfermedad, gracias al cual será posible la aplicación del tratamiento preventivo adecuado, con el consecuente ahorro de productos terapéuticos y disminución de la mortalidad. Para ello, se ha programado un sistema experto en cuyo motor de inferencia se combina el potencial de la lógica borrosa con el método de transmisión de la incertidumbre conocido como teoría de Dempster-Shafer. 2,- La predicción de las condiciones físico-químicas permite al mismo tiempo evaluar el comportamiento de la planta en su totalidad, de tal forma que el gestor puede adecuar las actividades de los operarios para, en el caso de un peligro significativo, establecer un sistema de control que modifique la desviación de los parámetros afectados hasta sus niveles normales. El problema de la predicción de los parámetros físico-químicos se ha resuelto mediante la aplicación conjunta de técnicas estadísticas clásicas (regresión múltiple de series temporales, suavizados lineales, modelos MM, AR, ARMA y ARIMA) y modelos de Redes Neuronales Computacionales (RNCs). 3,- La predicción de la evolución de los parámetros poblacionales facilita el control de la producción, mortalidad, distribución de las raciones diarias de alimento, seguimiento del stock, y puede servir como indicativo de la estabilidad o variabilidad de las condiciones ambientales dentro de la explotación. Permite, por otra parte, la definición de lo que se conoce como estrategia de producción, en la que se define la forma de comercialización del producto y su impacto sobre el stoc
Fermion family recurrences in the Dyson-Schwinger formalism
We study the multiple solutions of the truncated propagator Dyson-Schwinger
equation for a simple fermion theory with Yukawa coupling to a scalar field.
Upon increasing the coupling constant , other parameters being fixed, more
than one non-perturbative solution breaking chiral symmetry becomes possible
and we find these numerically. These ``recurrences'' appear as a mechanism to
generate different fermion generations as quanta of the same fundamental field
in an interacting field theory, without assuming any composite structure. The
number of recurrences or flavors is reduced to a question about the value of
the Yukawa coupling, and has no special profound significance in the Standard
Model. The resulting mass function can have one or more nodes and the
measurement that potentially detects them can be thought of as a collider-based
test of the virtual dispersion relation for the charged
lepton member of each family. This requires three independent measurements of
the charged lepton's energy, three-momentum and off-shellness. We illustrate
how this can be achieved for the (more difficult) case of the tau lepton
Influence of the electric energy non-regulated market in the intensive aquaculture plants associated to cooling effluents
En este trabajo se analiza el efecto que la liberalización del mercado eléctrico tiene
sobre la variación de los regímenes de temperatura del agua en plantas de acuicultura
intensiva que aprovechan los efluentes de refrigeración de centrales generadoras de electricidad.
Para ello se han utilizado datos de una instalación dedicada al engorde de anguilas
europeas, la cual toma el agua caliente del efluente de refrigeración de la Central Térmica
de Puente Nuevo (Córdoba). Los resultados indican que la liberalización del
mercado del sector eléctrico tiene una influencia significativa sobre la forma y cantidad
de energía generada por la Central Térmica, y por consiguiente sobre el régimen termal
del efluente de refrigeración. Los niveles de temperatura en el interior de la instalación
son dependientes asimismo de la temperatura del agua en el efluente de refrigeración,
estimándose la disminución de los índices de crecimiento debidos a este factor en un 5%.In this paper, the effect of the electric energy non-regulated market in the water
thermal regimes variation of intensive fishfarms that use the heated water for cooling of
power plants is analysed. This way, data of aneel intensive rearing system was used. In
this fishfarm the heated water is drawn from the cooling effluent of the Puente Nuevo
power plant (Córdoba). The results show that the non-regulated market has a significant effect on the form and amount of generated energy and the thermal regime of the cooling
effluent. The temperature levels in the fishfarm depend of the water temperature of
cooling effluent, being estimated the decrease of the growth index in 5%
El procesamiento de la información de las personas mayores y su actitud hacia el anuncio
Population ageing is a phenomenon of great socio-economic importance with major consequences for business. Analysis of older consumers and of their peculiarities is important for achieving effective advertising communication. This study analyses the antecedents of older people’s attitude to the ad and its effects on the brand attitude and purchasing intention in conditions of low involvement with the ad. From a sample consisting of 509 individuals, the general model posited is confirmed and older people are found to use both persuasion paths jointly in the cognitive processing of the ad.El envejecimiento poblacional es un hecho de gran transcendencia socioeconómica con importantes repercusiones empresariales. Es importante el análisis del consumidor mayor y de sus particularidades para la consecución de una efectiva comunicación publicitaria. En este trabajo se analizan los antecedentes de la actitud ante el anuncio de las personas mayores y sus consecuencias sobre la actitud hacia la marca y la intención de compra en condiciones de baja implicación con el anuncio. Sobre una muestra constituída por 509 sujetos se confirma el modelo general planteado y se defiende que las personas mayores utilizan conjuntamente las dos rutas de persuasión en el procesamiento cognitivo del anuncio
Integrating local environmental data and information from non-driven citizen science to estimate jellyfish abundance in Costa del Sol (southern Spain)
Tourism, fishing and aquaculture are key economic sectors of Costa del Sol (southern Iberian Peninsula). The management of these activities is sometimes disturbed by the onshore arrival and stranding of jellyfish swarms. In the absence data on the occurrence of these organisms, it may be interesting to explore data from non-driven systems, such as social networks. The present study show how data in text format from a mobile app called Infomedusa can be processed and used to model the relationship between estimated abundance of jellyfish on the beaches and local environmental conditions. The data retrieved from this app using artificial intelligence procedures (transition network or TN algorithm), were used as input for GAM models to estimate the abundance of jellyfish based on wind speed and direction. The analysis of data provided by Infomedusa indicated that only 30.39% of messages provided by the users had information about absence/presence of jellyfishes in the beaches. On the other hand, the TN processing capacity showed an accuracy level to discriminate messages with information on absence/presence of jellyfish slightly higher than 80%. GAM models considering the wind direction and speed of previous day explained between 37% and 77% of the variance of jellyfish abundance estimate from Infomedusa data. In conclusion, this approach may contribute to the development of a system for predicting the onshore arrival of jellyfish in the Costa del Sol.Versión del edito
Chapter 19. The Blackspot seabream fishery in the Strait of Gibraltar: lessons and future perspectives of shared marine resource
The Blackspot seabream (Pagellus bogaraveo) is one of the most important commercially-exploited fish species for the Spanish and Moroccan fleets which operate in the Strait of Gibraltar. In recent years, landings of Blackspot seabream in the main ports have decreased significantly respect previous periods of maximum catches, which makes it necessary to properly assess the abundance before establishing a management plan to make the fishery sustainable over time. In this chapter, we describe three different approaches to assess the abundance of this species in the Strait of Gibraltar. The results of three approaches tested (LCA/VPA, Gadget model and SimFish model) point out that from the 2010 the stock is kept at very low levels that oscillate between 900 and 1600 t, which supposes that the total biomass is between a 16% and 29% of the potential biomass. Additionally, the reference point values estimated by LCA/VPA and Gadget (F0.1 = 0.12-0.17) imply a clear overexploitation of the resource what is reinforced by the SimFish model results indicating that at least the 64% of abundance variation is a consequence of the fishery component.En prens
Double Nanowires for Hybrid Quantum Devices
Parallel 1D semiconductor channels connected by a superconducting strip constitute the core platform in several recent quantum device proposals that rely, for example, on Andreev processes or topological effects. In order to realize these proposals, the actual material systems must have high crystalline purity, and the coupling between the different elements should be controllable in terms of their interfaces and geometry. A strategy for synthesizing double InAs nanowires by the vapor-liquid-solid mechanism using III-V molecular beam epitaxy is presented. A superconducting layer is deposited onto nanowires without breaking the vacuum, ensuring pristine interfaces between the superconductor and the two semiconductor nanowires. The method allows for a high yield of merged as well as separate parallel nanowires with full or half-shell superconductor coatings. Their utility in complex quantum devices by electron transport measurements is demonstrated
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