Variación de las características mecánicas de armaduras de alta ductilidad B500SD en función de su grado de corrosión / Mechanical properties variation of B500SD high ductility reinforcement regarding its corrosion degree

Los efectos de la corrosión sobre las armaduras se manifiestan por la pérdida de sección y la variación de las propiedades mecánicas relacionadas con la ductilidad. En este trabajo se han ensayado a tracción 96 barras de acero B500SD que previamente se han sometido a niveles variables de corrosión. Los resultados muestran que los alargamientos de las barras disminuyen y el cociente entre la tensión máxima y el límite elástico aumenta conforme el nivel de corrosión avanza. A partir del estudio del efecto de entalla y de la distinta constitución metalográfica del acero a nivel de sección debido a su procedimiento de fabricación se pueden explicar los fenómenos anteriores

Ontogenetic Shifts in Terrestrial Reliance of Stream-Dwelling Brown Trout

This study focuses on terrestrial reliance of brown trout (Salmo trutta) and compared it to the potential prey available (macrozoobenthos and drifting invertebrates) in three temperate rivers (Galicia, NW Spain), with special emphasis on variations in terrestrial energy intake through the ontogeny of brown trout. Additionally, we paid particular attention to individual variation of terrestrial resource use within and between age classes. Prey items were grouped in four categories: i) aquatic invertebrates; ii) imagoes of aquatic invertebrates; iii) terrestrial invertebrates; and iv) fish prey. Next, energy composition was measured according to dry weight-energy equations for each individual in line with above-mentioned prey categories. Our findings illustrate that terrestrial invertebrates appeared to be scarce in the environment, whereas aquatic food resources were rather abundant and accessible. The use of terrestrial invertebrates tended to increase with age, but with a high degree of inter-individual variation in resource use. In fact, the individual reliance of brown trout on terrestrial invertebrates may vary considerably (between 0% and 76.9%). Besides, the frequency of terrestrial foragers, i.e., individuals with terrestrial invertebrates in their stomachs, increased with age, except in one population which had the maximum value in the age-2 class. The acquisition of terrestrial invertebrates thus appears to be a process strongly dependent upon the actual food availability in the environment, but with a high degree of individual variance in resource use within the same age class. Finally, we discuss that terrestrial invertebrates may largely contribute to cover the energy intake of the species, highlighting the interface between terrestrial and aquatic ecosystems, and thereby the importance of riparian canopy cover as a key factor for food supply of stream-dwelling salmonids speciesThe authors would like to thank the staff of the Station of Hydrobiology of the USC ‘Encoro do Con’ for their participation in the field work. We also appreciate the constructive comments on the manuscript given by one anonymous referee. J. Sánchez-Hernández was supported by a postdoctoral grant from the Galician Plan for Research, Innovation, and Growth 2011-2015 (Plan I2C, Xunta de Galicia)S

Anisakis infection in allis shad, Alosa alosa (Linnaeus, 1758), and twaite shad, Alosa fallax (Lacépède, 1803), from Western Iberian Peninsula Rivers : zoonotic and ecological implications

Acknowledgments The authors would like to thank M. N. Cueto and J.M. Antonio (ECOBIOMAR) for their excellent technical support and also Rodrigo López for making the map of the study area. We also thank the personal of the Vigo IEO, for providing information about shad captures at sea collected on the basis of national program (AMDES) included in the European Data Collection Framework (DCF) project. We are also grateful to Comandancia Naval de Tui for providing fishing data. M. Bao is supported by a PhD grant from the University of Aberdeen and also by financial support of the contract from the EU Project PARASITE (grant number 312068). This study was partially supported by a PhD grant from the Portuguese Foundation for Science and Technology (FCT) SFRH/BD/44892/2008) and partially supported by the European Regional Development Fund (ERDF) through the COMPETE—Operational Competitiveness Programme and national funds through Foundation for Science and Technology (FCT), under the project BPEst-C/MAR/ LA0015/2013. The authors thank the staff of the Station of Hydrobiology of the USC BEncoro do Con^ due their participation in the surveys. This work has been partially supported by the project 10PXIB2111059PR of the Xunta de Galicia and the project MIGRANET of the Interreg IV BSUDOE (South-West Europe) Territorial Cooperation Programme (SOE2/P2/E288). D.J. Nachón is supported by a PhD grant from the Xunta de Galicia (PRE/2011/198)Peer reviewedPostprin

Evaluación del lavado gástrico como herramienta para el análisis de la dieta en trucha común

Se ha estudiado la eficacia del método de extracción del contenido estomacal mediante el procedimiento de lavado estomacal a través de una bomba diseñada a partir del modelo original de Seaburg (1957). La efectividad del método no esta relacionada con el tamaño del pez, sino más bien con las propias características morfológicas de las presas, el estado de repleción del estómago y el grado de digestión del alimento. Así, la efectividad del método está inversamente relacionada con el estado de repleción. Además, presas de gran tamaño y que presentan estructuras rígidas como los Aeshnidae y los Tricópteros con estuches son más difíciles de expulsar. No obstante, las diferencias observadas en la efectividad de expulsión entre presas con las mismas características se deben al diferente grado de digestión de las mismas. Aún así, la efectividad media del método es elevada y superior al 80 %. Se trata pues de una metodología relativamente sencilla y eficaz, por lo que su uso es adecuado para la obtención de muestras de contenido estomacal en juveniles y adultos de trucha común.The efficacy of the method of extracting stomach content, by means of the procedure of stomach washing through a pump, based on Seaburg's original model (1957), has been studied. The effectiveness of the method is not related to the size of the fish, but rather to the prey's own morphological characteristics, the degree of repletion of the stomach and the extent of digestion of the food. Thus, the effectiveness of the method is inversely related to the degree of repletion. Furthermore, bigger prey having rigid structures, such as Aeshnidae and Caddisflies with cases are more difficult to expel. However, the observed differences in the effectiveness of expulsion between preys with similar characteristics are due to the extent of their digestion. Nevertheless, the average effectiveness of the method is high and in excess of 80 %. It is therefore a relatively simple and effective methodology and the reason why its use is appropriate for obtaining stomach content samples in young and adult brown trout

Descripción de la larva de Micrasema servatum (Navás, 1918) (Trichoptera, Brachycentridae)

The larva of Micrasema servatum (Navás, 1918), an endemic species of the Iberian Peninsula, is described for the first time and compared with those known of other Iberian species. The most important diagnostic features are illustrated and some taxonomic, zoogeographical and ecological notes are presented. Larva of M. servatum is, for the moment, the only known European species of the genus with four mesonotal sclerites and a case made of vegetal fragments in combination.La larva de Micrasema servatum (Navás, 1918), una especie endémica de la Península Ibérica, se describe por vez primera comparándola con el resto de las especies ibéricas del género. Se ilustran sus caracteres diagnósticos más importantes y se realizan algunas observaciones taxonómicas, zoogeográficas y ecológicas. Por el momento, M. servatum es la única especie europea de este género cuya larva combina la presencia de cuatro escleritos mesonotales con la construcción de un estuche de naturaleza vegetal

Hydrogen Production by Steam Reforming of Ethanol on Rh-Pt Catalysts: Influence of CeO2, ZrO2, and La2O3 as Supports

CeO2-, ZrO2-, and La2O3-supported Rh-Pt catalysts were tested to assess their ability to catalyze the steam reforming of ethanol (SRE) for H2 production. SRE activity tests were performed using EtOH:H2O:N2 (molar ratio 1:3:51) at a gaseous space velocity of 70,600 h−1 between 400 and 700 °C at atmospheric pressure. The SRE stability of the catalysts was tested at 700 °C for 27 h time on stream under the same conditions. RhPt/CeO2, which showed the best performance in the stability test, also produced the highest H2 yield above 600 °C, followed by RhPt/La2O3 and RhPt/ZrO2. The fresh and aged catalysts were characterized by TEM, XPS, and TGA. The higher H2 selectivity of RhPt/CeO2 was ascribed to the formation of small (~5 nm) and stable particles probably consistent of Rh-Pt alloys with a Pt surface enrichment. Both metals were oxidized and acted as an almost constant active phase during the stability test owing to strong metal-support interactions, as well as the superior oxygen mobility of the support. The TGA results confirmed the absence of carbonaceous residues in all the aged catalysts.The authors are grateful to the Universidad de La Sabana and Universidad de Alicante for the financial support of this work

The hidden advantage of delegation: pareto-improvements in a gift-exchange game

This paper analyzes the effect on performance and earnings of delegating the wage choice to employees. Our results how that such delegation significantly increases effort levels. Moreover, we observe a Pareto-improvement, as the earnings of both employers and employees increase when employers delegate than when they do not. Interestingly, we also find that the employees’ performance under delegation is higher than under non-delegation, even for similar wages. While there is strong evidence that behavior reflects strategic considerations, this result also holds for one-shot interactions. A possible non-strategic motivation explaining the positive reaction to delegation is a sense of enhanced responsibility