Collimating lenses from non-Euclidean transformation optics

Based on the non-Euclidean transformation optics, we design a thin metamaterial lens that can achieve wide-beam radiation by embedding a simple source (a point source in three-dimensional case or a line current source in two-dimensional case). The scheme is performed on a layer-by-layer geometry to convert curved surfaces in virtual space to flat sheets, which pile up and form the entire lens in physical space. Compared to previous designs, the lens has no extreme material parameters. Simulation results confirm its functionality.Comment: 12 pages, 6 figure

Contextual intelligence and expertise in soccer

Para los entrenadores la inteligencia en el juego es uno de los intangibles que predicen el éxito en la competición. De ahí que el objetivo de este estudio fuera analizar la percepción que jugadores de fútbol de diferente nivel de pericia tenían de su inteligencia para el juego. Se aplicó el Cuestionario de Inteligencia Contextual en el Deporte (ICD) que evalúa tres dimensiones: Inteligencia Anticipatoria, Inteligencia Táctica e Inteligencia Competitiva. En este estudio participaron 690 jugadores de fútbol de diferente nivel competitivo. Los resultados mostrarion que a medida que aumentaba el nivel competitivo se incrementaba la percepción de los jugadores sobre su inteligencia contextual. Este estudio confirma el papel que para los jugadores posee el sentirse competentes para solucionar los problemas tácticos de su deporte y que este sentimiento aumenta con su nivel de competencia.Coaches consider that game intelligence is one of the main elements that can predict success in competition. The objective of this study was to analize the perceptions that soccer players of different level of expertise had about their intelligence in the field. The Contextual Intelligence Questionnaire (ICD) was applied to a sample of spanish soccer players. This instrument evaluate three dimensions: Anticipatory intelligence, Tactical Intelligence and Competitive Intelligence. Six hundred and ninety of spanish soccer players of different level of expertise, participated in this study. Results showed that this self-perception increased with the level of players. This study confirmed the relevance of feeling able of solving tactical problems in the game, and how this feeling increase with the level of expertise.El presente estudio se pudo llevar a cabo gracias a la ayuda a la investigación concedida por la Cátedra Real Madrid- Universidad Europea de Madrid en su convocatoria 201

Dieta otoño-invernal de tres carnívoros, visón europeo (Mustela lutreola), nutria euroasiática (Lutra lutra)

This study describes the autumn-winter diet of three carnivores (Mustela lutreola, Lutra lutra and Genetta genetta) in northern Spain. Diet composition was analysed from 85 European mink, 156 otter and 564 spotted genet fecal samples The European mink diet was based on small mammals (relative frequency of occurrences 38.1%), fish (30.9%) and birds (16.7%). Spotted genet consumed mainly small mammals, birds and fruits, whilst otter predated practically only fish (95%). Using Levins’ index, trophic-niche widths in European mink, small–spotted genet and Eurasian otter were 3.76, 3.77 and 1.10, respectively. The trophic niche overlap by Pianka index for autumn-winter was 0.77 for European mink vs. Small-spotted genet, and 0.60 for European mink vs. otter. The average size of brown trout taken by otter was larger than those consumed by European mink. Key words: European mink (Mustela lutreola), Eurasian otter (Lutra lutra), Small–spotted genet (Genetta genetta), Diet, Spain.This study describes the autumn-winter diet of three carnivores (Mustela lutreola, Lutra lutra and Genetta genetta) in northern Spain. Diet composition was analysed from 85 European mink, 156 otter and 564 spotted genet fecal samples The European mink diet was based on small mammals (relative frequency of occurrences 38.1%), fish (30.9%) and birds (16.7%). Spotted genet consumed mainly small mammals, birds and fruits, whilst otter predated practically only fish (95%). Using Levins’ index, trophic-niche widths in European mink, small–spotted genet and Eurasian otter were 3.76, 3.77 and 1.10, respectively. The trophic niche overlap by Pianka index for autumn-winter was 0.77 for European mink vs. Small-spotted genet, and 0.60 for European mink vs. otter. The average size of brown trout taken by otter was larger than those consumed by European mink. Key words: European mink (Mustela lutreola), Eurasian otter (Lutra lutra), Small–spotted genet (Genetta genetta), Diet, Spain.Se describe la dieta otoño-invernal de tres carnívoros (Mustela lutreola, Lutra lutra y Genetta genetta) en el norte de España. La dieta fue analizada a partir de 85 muestras de visón europeo, 156 de nutria euroasiática y 564 de gineta común. El visón europeo basó su dieta en micromamíferos (38,1% de frecuencia relativa), peces (30,9%) y aves (16,7%). La gineta común consumió principalmente micromamíferos, aves y frutos, mientras la nutria predó casi exclusivamente peces (95%). Los índices de Levins de la anchura del nicho trófico del visón europeo, la gineta común y la nutria fueron 3,76, 3,77 y 1,10 respectivamente. Los solapamientos del nicho trófico durante otoño-invierno del visón europeo (índice de Pianka) respecto a la gineta común y la nutria euroasiática fueron 0,77 y 0,60, respectivamente. El tamaño medio de las truchas consumidas por las nutrias fue mayor que el de las consumidas por el visón europeo. Palabras clave: Visón europeo (Mustela lutreola), Nutria euroasiática (Lutra lutra), Gineta común (Genetta genetta), Dieta, España

Edad y crecimiento de Barbus graellsii Steindachner, 1866 y Chondrostoma miegii, Steindachner, 1866 (Pisces, Cyprinidae) en el río Cinca (cuenca hidrográfica del Ebro, NE España)

The age and growth of two endemic cyprinids from the lberian peninsula were studied for one year in a stretch of the Cinca River. There were caught by electrofishing 279 individuals of B. graellsii and 189 individuals of Ch. miegii. lmmature specimens of both species were not caught probably due to their migratory behaviour during the reproductive period. B. graellsii presented a maximum of 11 age classes in both sexes. Female Ch. miegii live for 8 years and males seven years. Growth was allometric in B. graellsii specimens whereas Ch. miegii showed isometric growth. Females were longer than males in both species. B. graellsii females showed higher growth rates than males whereas Ch. miegii showed similar growth rates between sexes. B. graellsii males showed a significant increase in condition before the reproductive period and a decrease in condition during this period, while females only showed a significant decrease in condition in July. Ch. miegii females presented dynamics of condition very similar to B. graellsii males. Key words: Age, Growth, Cyprinidae, Barbus graellsii, Chondrostoma miegii.The age and growth of two endemic cyprinids from the lberian peninsula were studied for one year in a stretch of the Cinca River. There were caught by electrofishing 279 individuals of B. graellsii and 189 individuals of Ch. miegii. lmmature specimens of both species were not caught probably due to their migratory behaviour during the reproductive period. B. graellsii presented a maximum of 11 age classes in both sexes. Female Ch. miegii live for 8 years and males seven years. Growth was allometric in B. graellsii specimens whereas Ch. miegii showed isometric growth. Females were longer than males in both species. B. graellsii females showed higher growth rates than males whereas Ch. miegii showed similar growth rates between sexes. B. graellsii males showed a significant increase in condition before the reproductive period and a decrease in condition during this period, while females only showed a significant decrease in condition in July. Ch. miegii females presented dynamics of condition very similar to B. graellsii males. Key words: Age, Growth, Cyprinidae, Barbus graellsii, Chondrostoma miegii.The age and growth of two endemic cyprinids from the lberian peninsula were studied for one year in a stretch of the Cinca River. There were caught by electrofishing 279 individuals of B. graellsii and 189 individuals of Ch. miegii. lmmature specimens of both species were not caught probably due to their migratory behaviour during the reproductive period. B. graellsii presented a maximum of 11 age classes in both sexes. Female Ch. miegii live for 8 years and males seven years. Growth was allometric in B. graellsii specimens whereas Ch. miegii showed isometric growth. Females were longer than males in both species. B. graellsii females showed higher growth rates than males whereas Ch. miegii showed similar growth rates between sexes. B. graellsii males showed a significant increase in condition before the reproductive period and a decrease in condition during this period, while females only showed a significant decrease in condition in July. Ch. miegii females presented dynamics of condition very similar to B. graellsii males. Key words: Age, Growth, Cyprinidae, Barbus graellsii, Chondrostoma miegii

Spiral nonimaging optical designs

Manufacturing technologies as injection molding or embossing specify their production limits for minimum radii of the vertices or draft angle for demolding, for instance. In some demanding nonimaging applications, these restrictions may limit the system optical efficiency or affect the generation of undesired artifacts on the illumination pattern. A novel manufacturing concept is presented here, in which the optical surfaces are not obtained from the usual revolution symmetry with respect to a central axis (z axis), but they are calculated as free-form surfaces describing a spiral trajectory around z axis. The main advantage of this new concept lies in the manufacturing process: a molded piece can be easily separated from its mold just by applying a combination of rotational movement around axis z and linear movement along axis z, even for negative draft angles. Some of these spiral symmetry examples will be shown here, as well as their simulated results

Novel free-form optical surface design with spiral symmetry

Manufacturing technologies as injection molding or embossing specify their production limits for minimum radii of the vertices or draft angle for demolding, for instance. These restrictions may limit the system optical efficiency or affect the generation of undesired artifacts on the illumination pattern when dealing with optical design. A novel manufacturing concept is presented here, in which the optical surfaces are not obtained from the usual revolution symmetry with respect to a central axis (z axis), but they are calculated as free-form surfaces describing a spiral trajectory around z axis. The main advantage of this new concept lies in the manufacturing process: a molded piece can be easily separated from its mold just by applying a combination of rotational movement around axis z and linear movement along axis z, even for negative draft angles. The general designing procedure will be described in detai

Edad, crecimiento y reproducción de Gobio gobio L. (Pisces, Cyprinidae) en un tramo regulado del río Segura (SE de España)

The age, growth and reproduction of Gobio gobio, were studied during a period of two years in a section of the Segura River regulated by the effect of a small upstream hydroelectric power station. A total of 254 specimens were caught monthly by electrofishing. The studied population showed a maximum of six age classes in females (0+–5+) and five in males (1+–5+). All females were mature at 2+ age class, whereas only 62.5% 2+ males showed mature gonads. During the studied period, both sexes showed maximum values of Gonadosomatic Index in May and spawn was different between the two studied periods. Compared with other populations, the studied population from a regulated locality is characterized by a non–seasonal body condition cycle and low captures of juvenile fish (0+, 1+) probably due to the effect of washing produced by drastic and unpredictable flow changes.La edad, crecimiento y reproducción de Gobio gobio, ha sido estudiada a lo largo de dos años en un tramo del río Segura regulado por una pequeña central hidroeléctrica. Mediante pesca eléctrica fueron capturados, mensualmente, un total de 254 ejemplares. Las hembras presentaron seis clases de edad (0+–5+) mientras que los machos presentaron cinco clases (1+–5+). Todas las hembras de clase de edad 2+ resultaron maduras mientras que los machos 2+ resultaron maduros en un 62,5% de los casos. Durante el periodo de estudio, ambos sexos presentaron los máximos valores del Índice Gonadosomático durante los meses de mayo aunque el desove resultó diferente entre los dos periodos estudiados. En comparación con otras poblaciones, la población estudiada en un tramo regulado del río se caracteriza por no presentar un ciclo estacional en la condición somática y bajas capturas de ejemplares juveniles (0+, 1+) debido, probablemente, al efecto de lavado provocado por los drásticos e impredecibles cambios en el caudal