638 research outputs found
Modelling of the circulation in the Northwestern Mediterranean Sea with the Princeton Ocean Model
International audienceThe Princeton Ocean Model ? POM (Blumberg and Mellor, 1987) has been implemented in the Northwestern Mediterranean nested (in one-way off-line mode) to a general circulation model of the Mediterranean Sea ? OGCM (Pinardi and Masetti, 2000; Demirov and Pinardi, 2002) in order to investigate if this model configuration is capable of reproducing the major features of the circulation as known from observations and to improve what has been made by previous numerical modeling works. According to the model results, the large-scale cyclonic circulation in the northern part of the Northwestern Mediterranean is, at least in the upper layers, less coherent in winter and spring than in summer and autumn. Furthermore, there is evidence that the mesoscale structure (eddies and meanders) is, during all year, a significant dynamic characteristic in this region of the Mediterranean Sea. Finally, concerning the circulation in the lower layers has been confirmed that the Levantine Intermediate Water and the Western Mediterranean Deep Water follow essentially a cyclonic path during all year
Effects of sudden salinity changes on the oxygen consumption and osmoregulatory parameters in the Senegales sole (Solea senegalensis Kaup, 1858)
Senegalese sole juveniles were held into flow-through respirometers and submitted to a sudden salinity change. Briefly, 40-50 g body weight fish were kept into chambers with initial salinity of 37.5 ppt (the same as in culture tanks) and, after an acclimation of 4 hours, the salinity was changed to 5 or 55 ppt. A control group did not experience any salinity alteration. Oxygen consumption was registered every 14 min and fish were sampled (gill biopsy and plasma) at different times (at t=4.5 h and t=7 h in order to determine gill Na+,K+- ATPase activity and plasma cortisol concentration. At t=4.5 h, oxygen consumption showed an inverse relationship with salinity, while gill Na+,K+- ATPase activity increased. Plasma cortisol levels presented a "U-shaped" relationship with salinity. At 7 h, oxygen consumption was higher in the control group, while cortisol and gill Na+,K+- ATPase activity varied in parallel to salinity. Our results suggest that sudden salinity changes evoked an acute stress situation (cortisol increased up to 15x over the basal level) which was slightly attenuate after 7 h. Fish quickly adapted its respiration rate to the new environmental conditions and this rate returned progressively to its normal values after the shock. Regarding enzyme activity, fish increased (55 ppt) or decreased (5 ppt) the ATPase activity depending on the salinity, as described in other studies.This work was supported by Interreg Project 0251_ECOAQUA_5_E, financed by the EDRF (European Regional Development Fund). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.
Juveniles de lenguado senegalés fueron mantenidos en respirómetros y sometidos a un cambio brusco de salinidad. Resumidamente, peces de 40-50 g se mantuvieron a una salinidad de 37.5 ppt y, después de una aclimatación de 4 horas, la salinidad se varió a 5 ó 55 ppt. Un grupo control no experimentó ninguna alteración. El consumo de oxígeno fue registrado cada 14 min y los peces fueron muestreados (plasma y branquias) a diferentes tiempos (t=4.5 h y t=7 h para determinar la actividad Na+,K+- ATPasa branquial la concentración de cortisol en plasma). A t=4.5 h, el consumo de oxígeno fue inversamente proporcional con la salinidad, mientras que la actividad Na+,K+- ATPasa branquial creció. El cortisol plasmático presentó una curva en forma de "U" en función de la salinidad. A t=7 h, el consumo de oxígeno fue mayor en el grupo control, mientras que la Na+,K+- ATPasa branquial varió en paralelo con la salinidad. Nuestros resultados sugieren que un cambio brusco de salinidad provoca una situación de estrés agudo (cortisol aumenta 15 veces su valor basal), que se atenúa ligeramente después de 7 h. Los peces rápidamente adaptan su tasa respiratoria a esta nueva condición ambiental y luego varía progresivamente a su valor inicial. Respecto a la actividad enzimática, los peces aumentaron (55 ppt) o disminuyeron (5 ppt) la actividad ATPasa en función de la salinidad, como se ha descrito en previos trabajos.Este trabajo fue apoyado por el proyecto Interreg 0251_ECOAQUA_5_E , financiado por el FEDER (Fondo Europeo de Desarrollo Regional). www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.</p
Kidney regeneration and repair after transplantation
PURPOSE OF REVIEW: To briefly show which are the mechanisms and cell types involved in kidney regeneration and describe some of the therapies currently under study in regenerative medicine for kidney transplantation. RECENT FINDINGS: The kidney contains cell progenitors that under specific circumstances have the ability to regenerate specific structures. Apart from the knowledge gained in the self-regenerative properties of the kidney, new concepts in regenerative medicine such as organ engineering and the use of mesenchymal stem cell-based therapies are currently the focus of attention in the field. SUMMARY: Overall, kidney regeneration is a reality and the knowledge on how to control it will be one of the main scopes in the present and future
Reproduction of the wedge sole (Dicologoglossa cuneata Moreau) in captivity: spawning parameters and influence of the natural temperature
In this work, the wedge sole (Dciologoglossa cuneata) spawning under natural thermocycle has been studied. The spawning parameters were similar to those of other flatfish in captivity, the relative fecundity being very high (1.7±0.1 ·106 eggs Kg female-1 per spawning season). The percentage of floating eggs decreased in parallel to the time and was directly related to egg diameter, daily relative fecundity and fertilization rate. Nevertheless, the hatching rate variations were not correlated to any other spawning parameter. The temperature range during the spawning season was very wide (11-21 ºC) though the largest spawns occurred between 12 and 16 ºC . The natural temperature cycle influenced wedge sole egg production, the winter temperature minimum indicating the onset of spawning, but the variations in the reproductive season did not appear to affect the daily egg production. Future research should focus on the photoperiod and its interaction with temperature as key factor for spawning.
This work was supported by Interreg Project 0251_ECOAQUA_5_E, financed by the EDRF (European Regional Development Fund).
www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua..
El presente trabajo trata del estudio de las puestas de la acedía (Dicologoglossa cuneata) en cautividad bajo condiciones naturales de temperatura. Los parámetros de puesta fueron similares a los de otros peces planos en cautividad, siendo la fecundidad relativa muy alta (1.7±0.1 ·106 huevos Kg hembra-1 por estación reproductora). El porcentaje de huevos flotantes disminuyó paralelamente con el tiempo y fue directamente proporcional al diámetro de huevos, fecundidad relativa diaria y tasa de fecundación. Sin embargo, las variaciones de la tasa de eclosión no estuvieron correlacionadas con ningún parámetro de puesta. El rango de temperatura durante la estación de puesta fue muy amplio (11-21 ºC), aunque las mayores puestas tuvieron lugar entre 12 y 16 ºC. El ciclo natural de temperatura tuvo efectos sobre la producción de huevos de acedía, con los mínimos invernales indicando el comienzo de la puesta, aunque las variaciones dentro de la estación de puesta no pareció afectar a la producción diaria de huevos.
Este trabajo fue apoyado por el proyecto Interreg 0251_ECOAQUA_5_E , financiado por el FEDER (Fondo Europeo de Desarrollo Regional).www.juntadeandalucia.es/agriculturaypesca/ifapa/ecoaqua.</p
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