14 research outputs found

    The impact of deep-sea fisheries and implementation of the UNGA Resolutions 61/105 and 64/72. Report of an international scientific workshop

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    The scientific workshop to review fisheries management, held in Lisbon in May 2011, brought together 22 scientists and fisheries experts from around the world to consider the United Nations General Assembly (UNGA) resolutions on high seas bottom fisheries: what progress has been made and what the outstanding issues are. This report summarises the workshop conclusions, identifying examples of good practice and making recommendations in areas where it was agreed that the current management measures fall short of their target

    Effects of ultramorphological changes on adhesion to lased dentin-scanning electron microscopy and transmission electron microscopy analysis

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    Dentin irradiation with erbium lasers has been reported to alter the composite resin bond to this treated surface. There is still a lack of studies reporting the effect of erbium lasers on dentin organic content and elucidating how laser treatment could interfere in the quality of the resin-dentin interface. This study aimed to evaluate the effect of erbium laser irradiation on dentin morphology and microtensile bond strength (μTBS) of an adhesive to dentin. Seventy-two dentin disks were divided into nine groups (n = 8): G1-Control (600-grit SiC paper); Er:YAG groups: G2-250 mJ/4 Hz; G3-200 mJ/4 Hz; G4-180 mJ/10 Hz; G5-160 mJ/10 Hz; Er,Cr:YSGG groups: G6-2 W/20 Hz; G7-2.5 W/20 Hz; G8-3 W/20 Hz; G9-4 W/20 Hz. Specimens were processed for cross-sectional analysis by scanning electron microscopy (SEM) (n = 3), transmission electron microscopy (TEM) (n = 2), and adhesive interface (n = 3). Forty-five dentin samples (n = 5) were restored and submitted to μTBS testing. ANOVA (α = 5%) revealed that G1 presented the highest μTBS values and irradiated groups did not differ from each other. TEM micrographs showed a superficial layer of denatured collagen fibrils. For SEM micrographs, it was possible to verify the laser effects extending to dentin subsurface presenting a rough aspect. Cross-sectional dentin micrographs of this hybridized surface revealed a pattern of modified tags with ringlike structures around it. This in vitro study showed that erbium laser irradiation interacts with the dental hard tissue resulting in a specific morphological pattern of dentin and collagen fibrils that negatively affected the bond strength to composite resin.74872072

    The impact of deep-sea fisheries and implementation of the UNGA Resolutions 61/105 and 64/72. Report of an international scientific workshop, National Oceanography Centre, Southampton

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    The scientific workshop to review fisheries management, held in Lisbon in May 2011, brought together 22 scientists and fisheries experts from around the world to consider the United Nations General Assembly (UNGA) resolutions on high seas bottom fisheries: what progress has been made and what the outstanding issues are. This report summarises the workshop conclusions, identifying examples of good practice and making recommendations in areas where it was agreed that the current management measures fall short of their target.Versión de edito

    Na+ and K+ body levels and survival of fingerlings of Rhamdia quelen (Siluriformes, Pimelodidae) exposed to acute changes of water pH. Níveis corporais de Na+ e K+ e sobrevivência de alevinos de Rhamdia quelen (Siluriformes, Pimelodidae) submetidos a variações agudas do pH da água.

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    The objective of this study was to investigate the effect of water pH on survival and Na+ and K+ body levels of fingerlings of Rhamdia quelen, a freshwater catfish. Survival was 100% at pH 4.00 to 9.0 throughout the experiment (96h), and death of all fingerlings was observed only at pH 3.75 or lower and at pH 10.50. There was a significant correlation between water pH and body Na+ levels (but not K+ levels) 72h after transfer. There was a clear reduction in Na+ levels when the transfer was to pH outside the 5.0 - 9.0 range, which is in agreement with the fact that fishes exposed to such pH’s present loss of ions by diffusion and/or a decrease in absorption. Growth experiments with this species probably would present best results within the 5.0 - 9.0 pH range, in which the decrease of body Na+ levels is reduced.<br>O objetivo deste estudo foi analisar o efeito do pH da água na sobrevivência e níveis corporais de Na+ e K+ de alevinos de Rhamdia quelen, um peixe de água doce. A sobrevivência foi de 100% ao longo do experimento (96h) na faixa de pH de 4,0 a 9,0, e foi observado mortalidade total dos alevinos em pH abaixo de 3,75 (e inclusive) e em pH 10,5. Houve uma correlação significativa entre o pH da água e os níveis corporais de Na+ (mas não de K+) 72h após a transferência. Quando os alevinos foram transferidos para um pH fora da faixa de 5,0 - 9,0, houve uma nítida redução dos níveis corporais de Na+, concordando com o fato que peixes expostos a esses níveis de pH apresentam perda de íons por difusão e/ou uma redução na sua absorção. O crescimento dessa espécie, provavelmente, é estimulado dentro da faixa de pH 5,0 - 9,0, na qual a diminuição dos níveis corporais de Na+ foi menor

    Foraging ecology and interactions with fisheries of wandering albatrosses (Diomedea exulans) breeding at South Georgia

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    Knowledge about the areas used by the foraging wandering albatross, Diomedea exulans, its prey and overlap with longline fisheries is important information not only for the conservation of this species but also for furthering our understanding of the ecology of its prey. We attached satellite-tracking devices and activity recorders to wandering albatrosses between May and July of 1999 and 2000 (years of differing food availability around South Georgia) in order to assess inter-annual variation in the main foraging areas, association with oceanographic features (i.e. fronts, bathymetry), diet and interactions with fisheries. The overall foraging patterns of the tracked birds were similar in 1999 and 2000, ranging between southern Brazil (28degreesS) and the Antarctic Peninsula (63degreesS) and between the waters off Tristan da Cunha (19degreesW) and the Patagonian Shelf and oceanic waters south of Cape Horn (68degreesW) in the South Atlantic. In 1999, wandering albatrosses spent most time in sub-Antarctic oceanic waters, their trip durations were significantly longer and they fed on fish and cephalopods (53 and 42% by mass, respectively). In contrast, in 2000, they spent more time in Antarctic waters, foraging trips were shorter and the diet was predominantly fish (84% by mass). Wandering albatrosses were associated with the sub-Antarctic Front (SAF; both years), Subtropical Front (STF; in 1999) and the Tropical Front (TF; in 2000) suggesting that this species exploits prey concentrated at oceanic fronts. Fisheries discards also seemed to provide a very good source of food. Several fish species that are targeted (e.g. Patagonian toothfish, Dissostichus eleginoides) or are available as offal/discards from commercial fisheries (e.g. the macrourids, Antimora rostrata and Macrourus holotrachys) were mainly associated with the South Georgia shelf and the Patagonian Shelf, respectively. Wandering albatross foraging areas overlapped with longline fisheries in three different regions: around South Georgia, at the Patagonian Shelf and in oceanic waters north of 40degreesS. Females commuted more frequently to the Patagonian Shelf and to oceanic areas where longline fisheries were operating. Males, on the other hand, spent more time on the shelf/shelf slope of South Georgia where they were more at risk from the local Patagonian toothfish fishery, particularly in 2000. These results emphasize that inter-annual variation in foraging preferences could lead to increased incidental mortality of this vulnerable species. Potential evidence for this is provided by a satellite-tracked wandering albatross (male; 1.8-day trip), whose diet contained a Patagonian toothfish head and a longline hook, and who spent extensive time in the water (44% of the time wet; 0.3 days of the trip) where a Patagonian toothfish longline fishing vessel was operating
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