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

Design of a compact objective for SWIR applications

Lately the short-wave infrared (SWIR) has become very important due to the recent appearance on the market of the small detectors with a large focal plane array. Military applications for SWIR cameras include handheld and airborne systems with long range detection requirements, but where volume and weight restrictions must be considered. In this paper we present three different designs of telephoto objectives that have been designed according to three different methods. Firstly the conventional method where the starting point of the design is an existing design. Secondly we will face design starting from the design of an aplanatic system. And finally the simultaneous multiple surfaces (SMS) method, where the starting point is the input wavefronts that we choose. The designs are compared in terms of optical performance, volume, weight and manufacturability. Because the objectives have been designed for the SWIR waveband, the color correction has important implications in the choice of glass that will be discussed 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

Raising awareness of the accessibility challenges in mathematics MOOCs

MOOCs provide learning environments that make it easier for learners to study from anywhere, at their own pace and with open access to content. This has revolutionised the field of eLearning, but accessibility continues to be a problem, even more so if we include the complexity of the STEM disciplines which have their own specific characteristics. This work presents an analysis of the accessibility of several MOOC platforms which provide courses in mathematics. We attempt to visualise the main web accessibility problems and challenges that disabled learners could face in taking these types of courses, both in general and specifically in the context of the subject of mathematics

Propiedades mecánicas y acústicas de hormigones con áridos reciclados y neumáticos fuera de uso

Industrial progress used to be linked to the produce of large waste volumes. These industrial by-products are deposited in landfills despite these ones could be used to manufacture others. In fact, the construction industry could incorporate these materials to contributing to greater environmental balance. This paper studies the manufactured of concrete using as aggregates two kind of different wastes: construction and demolition wastes as well as recycled tires rubber (NFU). Natural fine fraction is replaced by a 10% by volume of industrial products analyzed. The mechanical behaviour and the acoustic properties of concrete made with recycled aggregates are studied. Results show a reduction in mechanical properties by using recycled aggregates and NFU. Nevertheless, it is observed that concrete made with fine recycled aggregate fraction of NFU could be employed with all the guarantees to produce concrete for non-structural applications.El progreso industrial lleva asociado la generación de grandes volúmenes de residuos que, en la mayoría de los casos, acaban en los vertederos, desperdiciando su potencial como materias primas para otros sectores industriales, como es el sector de la construcción, por lo que debe considerarse su reutilización en nuevas aplicaciones e incorporación como subproducto en el campo de los materiales de construcción, dando lugar a materiales más ecoeficientes y respetuosos con el medioambiente. Este trabajo estudia el empleo de áridos reciclados procedentes de residuos de construcción y demolición, y caucho procedente de neumáticos fuera de uso (NFU) en la fabricación de hormigones. La fracción fina natural ha sido sustituida por un 10% en volumen de los subproductos industriales analizados. El comportamiento físico, mecánico y las propiedades acústicas de los hormigones ha sido comparado con los hormigones de referencia. En los resultados se observa una reducción de las resistencias mecánicas y del modulo de elasticidad por el empleo de áridos reciclados y NFU. Se muestra que los hormigones fabricados con la fracción fina de áridos reciclados y NFU podrían ser empleados con todas las garantías en hormigones para aplicaciones no estructurales

Performance analysis of AlGaAs/GaAs tunnel junctions for ultra-high concentration photovoltaics

An n(++)-GaAs/p(++)-AlGaAs tunnel junction with a peak current density of 10 100Acm(-2) is developed. This device is a tunnel junction for multijunction solar cells, grown lattice-matched on standard GaAs or Ge substrates, with the highest peak current density ever reported. The voltage drop for a current density equivalent to the operation of the multijunction solar cell up to 10 000 suns is below 5 mV. Trap-assisted tunnelling is proposed to be behind this performance, which cannot be justified by simple band-to-band tunnelling. The metal-organic vapour-phase epitaxy growth conditions, which are in the limits of the transport-limited regime, and the heavy tellurium doping levels are the proposed origins of the defects enabling trap-assisted tunnelling. The hypothesis of trap-assisted tunnelling is supported by the observed annealing behaviour of the tunnel junctions, which cannot be explained in terms of dopant diffusion or passivation. For the integration of these tunnel junctions into a triple-junction solar cell, AlGaAs barrier layers are introduced to suppress the formation of parasitic junctions, but this is found to significantly degrade the performance of the tunnel junctions. However, the annealed tunnel junctions with barrier layers still exhibit a peak current density higher than 2500Acm(-2) and a voltage drop at 10 000 suns of around 20 mV, which are excellent properties for tunnel junctions and mean they can serve as low-loss interconnections in multijunction solar cells working at ultra-high concentrations

The incorporation of construction and demolition wastes as recycled mixed aggregates in non-structural concrete precast pieces

Concern for the environment has lately heightened awareness about the need for recycling in the construction industry. However, some standards, such as the Spanish standard, only accept the recycling of aggregates derived from concrete, which limits the extensive use of construction and demolition waste, which are produced in much bigger volumes. The aim of this work was to explore the possibility of using recycled mixed aggregates (RMA) in the preparation of precast non-structural concretes. To that end different percentages of natural aggregate were replaced by RMA in non-structural elements (25, 50, 75 and 100%). Contents of cement, water, and the dosages commonly used by companies were unchanged by the introduction of RMA. The characterization of the prepared elements has been done using the specific tests for each type of non-structural element (terrazzo for indoor use, hollow tiles, kerbstones and paving blocks): compression and flexural strength, water absorption, dimensional tolerances, abrasion and slipping resistance. The paving blocks, kerbstones, and hollow tiles prepared were tested for 360 days. The stability of the tested properties confirmed the possibility of using these wastes on an industrial scale satisfying the standard requirements. However, the surface of terrazzo with RMA is not as good as that prepared with natural aggregate.The authors of this study would like to thank the Instituto de Fomento de la Región de Murcia for financing project 2009.03.ID + I.0065 in the Framework Programmes for Research and Technological Development

ATLAS silicon module assembly and qualification tests at IFIC Valencia

ATLAS experiment, designed to probe the interactions of particles emerging out of proton proton collisions at energies of up to 14 TeV, will assume operation at the Large Hadron Collider (LHC) at CERN in 2007. This paper discusses the assembly and the quality control tests of forward detector modules for the ATLAS silicon microstrip detector assembled at the Instituto de Fisica Corpuscular (IFIC) in Valencia. The construction and testing procedures are outlined and the laboratory equipment is briefly described. Emphasis is given on the module quality achieved in terms of mechanical and electrical stability.Comment: 23 pages, 38 EPS figures, uses JINST LaTeX clas