39 research outputs found

    Ambient Light Caching via Approximate Photon Mapping

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    Indirect illumination is an essential part of realistic computer-generated imagery. However, accurate calculation of indirect illumination comes at high compute costs. To this end, we replace lengthy indirect illumination paths by employing an ambient light cache based on photon mapping principles. By only performing cache queries after a certain path length has been reached, we show that significantly fewer photons than traditional photon mapping techniques are sufficient and that an inaccurate data structure can be used to store them. Despite these simplifications, our method generally outperforms unidirectional path tracing while adding little time overhead.CSE3000 Research ProjectComputer Science and Engineerin

    Co-Culturing Microalgae with Roseobacter Clade Bacteria as a Strategy for Vibrionaceae Control in Microalgae-Enriched Artemia

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    Bacterial communities associated with fish larvae are highly influenced by the microbiota of live prey used as feed (rotifers or Artemia), generally dominated by bacterial strains with a low degree of specialization and high growth rates, (e.g., Vibrionaceae), which can be detrimental to larvae. Co-cultivation of microalgae used in the enrichment of Artemia (e.g., Phaeodactylum tricornutum, or Chlorella minutissima) with Vibrio-antagonistic probiotics belonging to the Roseobacter clade bacteria (e.g., Phaeobacter spp. or Ruegeria spp.) was studied. The introduction of the probiotics did not affect microalgae growth or significantly modify the composition of bacterial communities associated with both microalgae, as revealed by DGGE analysis. The inoculation of P. tricornutum with Ruegeria ALR6 allowed the maintenance of the probiotic in the scale-up of the microalgae cultures, both in axenic and non-axenic conditions. Using Ruegeria-inoculated P. tricornutum cultures in the enrichment of Artemia reduced the total Vibrionaceae count in Artemia by 2 Log units, therefore preventing the introduction of opportunistic or pathogenic bacteria to fish larvae fed with them

    Co-Culturing Microalgae with <i>Roseobacter</i> Clade Bacteria as a Strategy for <i>Vibrionaceae</i> Control in Microalgae-Enriched <i>Artemia</i>

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    Bacterial communities associated with fish larvae are highly influenced by the microbiota of live prey used as feed (rotifers or Artemia), generally dominated by bacterial strains with a low degree of specialization and high growth rates, (e.g., Vibrionaceae), which can be detrimental to larvae. Co-cultivation of microalgae used in the enrichment of Artemia (e.g., Phaeodactylum tricornutum, or Chlorella minutissima) with Vibrio-antagonistic probiotics belonging to the Roseobacter clade bacteria (e.g., Phaeobacter spp. or Ruegeria spp.) was studied. The introduction of the probiotics did not affect microalgae growth or significantly modify the composition of bacterial communities associated with both microalgae, as revealed by DGGE analysis. The inoculation of P. tricornutum with Ruegeria ALR6 allowed the maintenance of the probiotic in the scale-up of the microalgae cultures, both in axenic and non-axenic conditions. Using Ruegeria-inoculated P. tricornutum cultures in the enrichment of Artemia reduced the total Vibrionaceae count in Artemia by 2 Log units, therefore preventing the introduction of opportunistic or pathogenic bacteria to fish larvae fed with them

    Isolation of phaeobacter sp. From larvae of atlantic bonito (sarda sarda) in a mesocosmos unit, and its use for the rearing of european seabass larvae (dicentrarchus labrax l.)

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    The target of this study was to use indigenous probiotic bacteria in the rearing of seabass larvae. A Phaeobacter sp. strain isolated from bonito yolk-sac larvae (Sarda sarda) and identified by amplification of 16S rDNA showed in vitro inhibition against Vibrio anguillarum. This Phaeobacter sp. strain was used in the rearing of seabass larvae (Dicentrarchus labrax L.) in a large-scale trial. The survival of seabass after 60 days of rearing and the specific growth rate at the late exponential growth phase were significantly higher in the treatment receiving probiotics (p < 0.05). Microbial community richness as determined by denaturing gradient gel electrophoresis (DGGE) showed an increase in bacterial diversity with fish development. Changes associated with the administration of probiotics were observed 11 and 18 days after hatching but were not apparent after probiotic administration stopped. In a small challenge experiment, seabass larvae from probiotic treatment showed increased survival (p < 0.05) after experimental infection with a mild pathogen (Vibrio harveyi). Overall, our results showed that the use of an indigenous probiotic strain had a beneficial impact on larval rearing in industry-like conditions.</p

    Live feeds for early stages of fish rearing

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    28 páginas, 2 tablas. Special Issue: Basic and Applied Aspects of Aquaculture Nutrition: Healthy Fish for Healthy Consumers. The definitive version is available at www.blackwell-synergy.comDespite the recent progress in the production of inert diets for fish larvae, feeding of most species of interest for aquaculture still relies on live feeds during the early life stages. Independently of their nutritional value, live feeds are easily detected and captured, due to their swimming movements in the water column, and highly digestible, given their lower nutrient concentration (water content>80%). The present paper reviews the main types of live feeds used in aquaculture, their advantages and pitfalls, with a special emphasis on their nutritional value and the extent to which this can be manipulated. The most commonly used live feeds in aquaculture are rotifers (Brachionus sp.) and brine shrimp (Artemia sp.), due to the existence of standardized cost-effective protocols for their mass production. However, both rotifers and Artemia have nutritional deficiencies for marine species, particularly in essential n-3 highly unsaturated fatty acids (HUFA, e.g., docosahexaenoic acid and eicosapentaenoic acid). Enrichment of these live feeds with HUFA-rich lipid emulsions may lead to an excess dietary lipid and sub-optimal dietary protein content for fish larvae. In addition, rotifers and Artemia are likely to have sub-optimal dietary levels of some amino acids, vitamins and minerals, at least for some species. Several species of microalgae are also used in larviculture. These are used as feed for other live feeds, but mostly in the ‘green water’ technique in fish larval rearing, with putative beneficial effects on feeding behaviour, digestive function, nutritional value, water quality and microflora. Copepods and other natural zooplankton organisms have also been used as live feeds, normally with considerably better results in terms of larval survival rates, growth and quality, when compared with rotifers and Artemia. Nonetheless, technical difficulties in mass-producing these organisms are still a constraint to their routine use. Improvements in inert microdiets will likely lead to a progressive substitution of live feeds. However, complete substitution is probably years away for most species, at least for the first days of feeding.This review was partially supported by projects: POCI/MAR/61623/2004 – SAARGO, financed by program POCI 2010 (FCT, Portugal), which is co-financed by FEDER; and project P06-AGR-01697 funded by Consejería Innovación, Ciencia y Empresa – Junta de Andalucía (Spain)+FEDER.Peer reviewe

    Environmental conditioning of skeletal anomalies typology and frequency in gilthead seabream (Sparus aurata L., 1758) juveniles.

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    In this paper, 981 reared juveniles of gilthead seabream (Sparus aurata) were analysed, 721 of which were from a commercial hatchery located in Northern Italy (Venice, Italy) and 260 from the Hellenic Center for Marine Research (Crete, Greece). These individuals were from 4 different egg batches, for a total of 10 different lots. Each egg batch was split into two lots after hatching, and reared with two different methodologies: intensive and semi-intensive. All fish were subjected to processing for skeletal anomaly and meristic count analysis. The aims involved: (1) quantitatively and qualitatively analyzing whether differences in skeletal elements arise between siblings and, if so, what they are; (2) investigating if any skeletal bone tissue/ossification is specifically affected by changing environmental rearing conditions; and (3) contributing to the identification of the best practices for gilthead seabream larval rearing in order to lower the deformity rates, without selections. The results obtained in this study highlighted that: i) in all the semi-intensive lots, the bones having intramembranous ossification showed a consistently lower incidence of anomalies; ii) the same clear pattern was not observed in the skeletal elements whose ossification process requires a cartilaginous precursor. It is thus possible to ameliorate the morphological quality (by reducing the incidence of severe skeletal anomalies and the variability in meristic counts of dermal bones) of reared seabream juveniles by lowering the stocking densities (maximum 16 larvae/L) and increasing the volume of the hatchery rearing tanks (minimum 40 m(3)). Feeding larvae with a wide variety of live (wild) preys seems further to improve juvenile skeletal quality. Additionally, analysis of the morphological quality of juveniles reared under two different semi-intensive conditions, Mesocosm and Large Volumes, highlighted a somewhat greater capacity of Large Volumes to significantly augment the gap with siblings reared in intensive (conventional) modality

    Current status of extensive and semi-intensie aquaculture practices in southern Europe

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    2 páginas. International Workshop on Sustainable Extensive and Semi-intensie Coastal Aquaculture in Southern Europe (SEACASE), Tavira, Portugal, january 20-21, 2010.In less then 30 years intensive fish farming has quickly become the first provider of marine farmed products. Yet, extensive and semi-intensive systems still represent significant amounts of production and use large places along the southern Europe coastal zones (artificial lagoons, natural and managed deltas, and semi closed bays and estuaries, encompassing polders with earthponds).Peer reviewe

    TestKnight: An Interactive Assistant to Stimulate Test Engineering

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    Software testing is one of the most important aspects of modern software development. To ensure the quality of the software, developers should ideally write and execute automated tests regularly as their code-base evolves. TestKnight, a plugin for the IntelliJ IDEA integrated development environment (IDE), aims to help Java developers improve the testing process through support for creating and maintaining high-quality test suites.Github repo: https://github.com/SERG-Delft/testknightJetbrains Marketplace: https://plugins.jetbrains.com/plugin/17072-testknightYouTube video: https://www.youtube.com/watch?v=BSaL-K7ug6MGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Software Engineerin
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