158 research outputs found

    Plankton and physico-chemical characteristics in earthen ponds used for traditional extensive fish farming in the bay of Cádiz (Spain). Comparison between old and recent built ponds

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    Main zooplankton groups, chlorophyll A, inorganic nutrients, organic matter, temperature and pH in water, as well as pH and redox potential in the sediment have been examined during eighteen months in a traditional farm of the Cádiz Bay (South Atlantic coast of the Iberian Peninsula). The study aimed in comparing two zones differing in the time of the sediment maturation.Peer reviewe

    Monolithic integration of Giant Magnetoresistance (GMR) devices onto standard processed CMOS dies

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    Giant Magnetoresistance (GMR) based technology is nowadays the preferred option for low magnetic fields sensing in disciplines such as biotechnology or microelectronics. Their compatibility with standard CMOS processes is currently investigated as a key point for the development of novel applications, requiring compact electronic readout. In this paper, such compatibility has been experimentally studied with two particular non-dedicated CMOS standards: 0.35 μm from AMS (Austria MicroSystems) and 2.5 μm from CNM (Centre Nacional de Microelectrònica, Barcelona) as representative examples. GMR test devices have been designed and fabricated onto processed chips from both technologies. In order to evaluate so obtained devices, an extended characterization has been carried out including DC magnetic measurements and noise analysis. Moreover, a 2D-FEM (Finite Element Method) model, including the dependence of the GMR device resistance with the magnetic field, has been also developed and simulated. Its potential use as electric current sensors at the integrated circuit level has also been demonstrated

    Do dietary amino acid profiles affect performance of larval gilthead seabream?

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    Live preys commonly used in fish larval rearing seem to be imbalanced in terms of amino acids. Manipulation of their amino acid composition is di fficult, but the use of microencapsulated diets allows this manipulation. This study analysed the effect of amino acid supplementation, in order to compensate for dietary amino acid imbalances, on growth and survival of gilthead seabream ( Sparus aurata ) larvae

    La composition en acides aminés, dans le régime alimentaire des larves de daurade royale, affecte-t-elle leur performance ?

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    7 páginas, 2 figuras, 4 tablas.[EN] Live preys commonly used in fish larval rearing seem to be imbalanced in terms of amino acids. Manipulation of their amino acid composition is difficult, but the use of microencapsulated diets allows this manipulation. This study analysed the effect of amino acid supplementation, in order to compensate for dietary amino acid imbalances, on growth and survival of gilthead seabream (Sparus aurata) larvae. Larvae were reared until 32 days after hatching, in a closed recirculating water system (19 °C), using only live food (rotifers and Artemia). Thereafter, larvae were fed Artemia or one of the experimental microencapsulated diets: supplemented with indispensable amino acids (IAAsup diet), or supplemented with dispensable amino acids (DAAsup diet). Experiment lasted for 10 days. Dietary supplementation with indispensable amino acids resulted in A/E ratios [(each indispensable amino acid) × (total indispensable amino acids)−1 × 1000] more similar to the ones of larval seabream and in higher IAA:DAA ratios than in the DAAsup diet. Survival was similar in larvae fed the IAAsup diet (75%) or Artemia (87%), but was significantly lower in larvae fed the DAAsup diet (52%). Larvae from all treatments more than doubled their average dry weight during the experimental period. Final dry weight was similar in larvae fed both microcapsules, but these were lighter than larvae fed with Artemia. Relative growth rate (RGR) and total biomass production tended to be higher in larvae fed the IAAsup (RGR = 9% day−1) than the DAAsup diet (RGR = 7.5% day−1) and only in this last treatment these parameters were significantly lower than in larvae fed with Artemia. Therefore, dietary supplementation with indispensable amino acids resulted in a more balanced dietary amino acid profile, which significantly increased survival. Further studies introducing microdiets earlier in the development seem necessary in order to optimise growth.[FR] Les proies vivantes utilisées dans les élevages larvaires semblent déséquilibrées en terme d'acides aminés. Manipuler la composition en acides aminés est difficile mais l'usage d'aliments encapsulés le permet. Cette étude analyse l'effet d'une supplémentation en acides aminés sur la croissance et la survie des larves de daurade royale (Sparus aurata) afin de compenser un déséquilibre. Les larves sont élevées jusqu'à 32 jours après éclosion en circuit fermé (eau à 19 °C), en utilisant des aliments vivants uniquement (rotifères et Artemia). Les larves sont ensuite nourries avec des Artemia ou bien avec des aliments microencapsulés expérimentaux, supplémentés en acides aminés soit indispensables (régime IAAsup) soit non-indispensables (régime DAAsup). La durée de l'expérience est de 10 jours. La supplémentation en acides aminés indispensables conduit à des ratios A/E [(chaque AA indispensable) × (total en AA indispensables)−1 × 1000] plus proches de ceux de la larve de dorade et des ratios IAA/DHA plus élevés que ne le fait la supplémentation en acides aminés non-indispensables. Le taux de survie est similaire chez les larves nourries avec le régime IAAsup (75 %) ou Artemia (87 %) mais inférieur significativement chez les larves soumises au régime DAAsup (52 %). Le poids sec moyen de ces larves, quel que soit leur régime alimentaire, a doublé durant la période expérimentale. Le poids sec est similaire chez les larves nourries de microcapsules mais moins élévé chez celles nourries d'Artemia. Le taux de croissance relative (RGR) et la production de biomasse totale tendent à être plus élevés chez les larves nourries en IAAsup (RGR = 9 % jour−1) que celles nourries en DAAsup (RGR = 7,5 % jour−1). C'est seulement dans ce dernier traitement que les paramètres sont plus faibles significativement que chez les larves nourries d'Artemia. Ainsi, les supplémentations alimentaires en acides aminés indispensables peuvent augmenter la survie. D'autres études, introduisant des micro-aliments de façon plus précoce dans le développement, semblent nécessaires afin d'optimiser la croissance.The authors acknowledge funding by project AGL2004-06669-C02-01 (MCYT, Spain) and grant SFRH/BPD/14835/2003 (FCT, Portugal).Peer reviewe

    Antioxidant activity of isolated compounds in non-volatile residue from orange essential oil

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    6 páginas, 3 figuras.[ES] Existe un creciente interés en la industria alimentaria y en la medicina preventiva por la búsqueda de «antioxidantes naturales», por lo que nos planteamos evaluar la actividad antioxidante del residuo no volátil del aceite esencial de naranja contra la oxidación del aceite de oliva sin retinar y de reciente extracción. Mediante destilación del aceite esencial de naranja se obtuvo el residuo no-volátil, el cual se fraccionó en columna de silica gel 60. La actividad antioxidante fue medida por el valor de peróxidos producidos por el aceite de oliva al provocar la oxidación por calentamiento a 70 °C durante 48 h. Se aislaron seis compuestos mediante H PLC preparativo de los cuales cuatro tuvieron actividad antioxidante. Usando métodos espectroscópicos se identificaron a-tocoferol y tres flavonas metoxiladas. Con este estudio se confirmó que la fracción no volátil del aceite esencial de naranja contiene antioxidantes naturales diferentes al a-tocoferol.[EN] There has been a growing interest in the food industry and in preventive medicine to search for «natural antioxidants». Therefore the objetive of this study was to evaluate the antioxidant activity of the non-volatile residue of essential orange oil in the oxidation of unrefined and freshly extracted olive oil. Essential orange oil was distilled to obtain a non-volatile residue and fracctionated on a Silica Gel 60 column. The antioxidant activity was determined by measuring peroxide value obtained after heating olive oil at 70 °C for 48 h. Six compounds were isolated and purified, four of these had antioxidant activity, a-tocopherol and three methoxylated flavones were identified using spectroscopic methods. This study confirmed that non-volatile fractions of essential orange oil contain natural antioxidants diferent from a-tocopherol.Peer reviewe

    Near-optimal replacement policies for shared caches in multicore processors

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    An optimal replacement policy that minimizes the miss rate in a private cache was proposed several decades ago. It requires knowing the future access sequence the cache will receive. There is no equivalent for shared caches because replacement decisions alter this future sequence. We present a novel near-optimal policy for minimizing the miss rate in a shared cache that approaches the optimal execution iteratively. During each iteration, the future access sequence is reconstructed on every miss interleaving the future per-core sequences, taken from the previous iteration. This single sequence feeds a classical private-cache optimum replacement policy. Our evaluation on a shared last-level cache shows that our proposal iteratively converges to a near-optimal miss rate that is independent of the initial conditions, within a margin of 0.1%. The best state-of-the-art online policies achieve around 65% of the miss rate reduction obtained by our near-optimal proposal. In a shared cache, miss rate optimization does not imply the optimization of other metrics. Therefore, we also propose a new near-optimal policy to maximize fairness between cores. The best state-of-the-art online policy achieves 60% of the improvement in fairness seen with our near-optimal policy. Our proposals are useful both for setting upper performance bounds and inspiring implementable mechanisms for shared caches.The authors acknowledge support from grants (1) PID2019-105660RB-C21 and PID2019-107255GB-C22 from Agencia Estatal de Investigación (AEI) from Spain and European Regional Development Fund (ERDF); (2) gaZ: T58_20R research group from Aragón Government and European Social Fund (ESF); and (3) 2014-2020 "Construyendo Europa desde Aragón" from European Regional Development Fund (ERDF).Peer ReviewedPostprint (author's final draft

    Transcriptomic characterization of the larval stage in gilthead seabream (Sparus aurata) by 454 pyrosequencing

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    Gilthead seabream (Sparus aurata) is a teleost belonging to the family Sparidae with a high economical relevance in the Mediterranean countries. Although genomic tools have been developed in this species in order to investigate its physiology at the molecular level and consequently its culture, genomic information on post-embryonic development is still scarce. In this study, we have investigated the transcriptome of a marine teleost during the larval stage (from hatching to 60 days after hatching) by the use of 454 pyrosequencing technology. We obtained a total of 68,289 assembled contigs, representing putative transcripts, belonging to 54,606 different clusters. Comparison against all S. aurata expressed sequenced tags (ESTs) from the NCBI database revealed that up to 34,722 contigs, belonging to about 61% of gene clusters, are sequences previously not described. Contigs were annotated through an iterative Blast pipeline by comparison against databases such as NCBI RefSeq from Danio rerio, SwissProt or NCBI teleost ESTs. Our results indicate that we have enriched the number of annotated sequences for this species by more than 50% compared with previously existing databases for the gilthead seabream. Gene Ontology analysis of these novel sequences revealed that there is a statistically significant number of transcripts with key roles in larval development, differentiation, morphology, and growth. Finally, all information has been made available online through user-friendly interfaces such as GBrowse and a Blast server with a graphical frontend

    Benthic macrofauna communities in coastal earthen ponds used for fish farming in the south atlantic coast of the iberian peninsula

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    Macrobenthos communities inhabiting coastal fish-farming earthen ponds have been studied during two yearly seasons in three different farms of the Gulf of Cádiz (SW Iberian Peninsula), two of them sited in Portugal (Portimao and Olhão) and one in Spain (Puerto Real). Each farm has a different culture system and hydrologic regime. We are presenting here the main characteristics, dominant species and/or taxonomic groups and differences among the three studied ponds.Peer reviewe
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