Restoration of Acipenser sturio L., 1758 in Germany: Growth characteristics of juvenile fish reared under experimental indoor conditions

The survival of the highly endangered Acipenser sturio L., 1758 depends nearly exclusively upon the establishment of captive broodstocks. Such measures were initiated in Germany in 1996, due to a transfer of 40 artificially reproduced individuals from France under a co-operation agreement. We report the results of rearing these fish for a period of 3 years under freshwater conditions. During the first year the fish being exclusively fed frozen chironomid larvae (N = 40) grew from a median of 27 cm (with range of 23-31 cm), averaging 71 g (42-112 g), to 43 cm (38-51 cm) and 280 g (168-505 g) at a mean temperature of 20 °C (13-27 °C). Following their transfer to larger tanks (approx. 5 m³) at a mean temperature of 21 °C (17-24 °C), the fish (N = 27) reached a length of 68 cm (56-76 cm), averaging 1 281 g (512-2 097 g) at the end of the second year. Decreasing growth and increasing food conversion rates (FCR) during the first four months of the third year made us change the food composition (addition of large chironomids, krill and small marine fish). An increase in growth and a decrease in FCR was observed over the next four months resulting in a median length of 76 cm (58-89 cm), with a weight of 1 827 g (855-3 462 g) at the end of the third year (N = 27). Our fish showed rather large differences in growth, with some individuals reaching the maximum weight gain observed in wild fish, thus indicating the potential to optimise results by future testing involving additional natural food items in order to develop a formulated diet to stimulate early sexual maturation.La supervivencia del altamente amenazado Acipenser sturio L., 1758 depende casi exclusivamente del establecimiento de stocks de cría en cautividad. Tales medidas fueron iniciadas en Alemania en 1996, gracias a la transferencia desde Francia bajo un convenio de cooperación de 40 individuos reproducidos artificialmente. Presentamos los resultados de la cría de estos peces por un periodo de tres años en condiciones dulceacuícolas. Durante el primer año los peces (N = 40) siendo alimentados exclusivamente con larvas congeladas de quironómidos crecieron desde una media de 27 cm (con rango de 23-31 cm), promediando 71 g (42-112 g), a 43 cm (38-51) y 280 g (168-505 g) a una temperatura media de 20 °C (13-27 °C). A continuación de su traslado a tanques más grandes (de aproximadamente 5 m³) a una temperatura media de 21 °C (17-24 °C), los peces (N = 27) alcanzaron una longitud de 68 cm (56-76 cm), promediando 1 281 g (521-2 097 g) al final del segundo año. La disminución del crecimiento y el incremento de las tasas de con versión de alimento (TCA) durante los primeros cuatro meses del tercer año nos hicieron cambiar la composición del alimento (adición de quironómidos de gran tamaño, krill y pequeños peces marinos). Un incremento en el crecimiento y una disminución de las TCA fueron observados durante los cuatro meses siguientes resultando una longitud media de 76 cm (58-89 cm), con un peso de 1 827 g (855-3 462 g) al final del tercer año (N = 27). Nuestros peces mostraron numerosas diferencias en crecimiento, con algunos individuos alcanzando la mayor ganancia en peso observada en peces silvestres, indicando así el potencial para optimizar resultados por futuras pruebas que incluyan alimentos naturales adicionales en orden a evaluar una dieta formulada para estimular la maduración sexual temprana.Instituto Español de Oceanografí

Total knee arthroplasty in valgus knee

SummaryTotal knee arthroplasty (TKA) in valgus knee has the reputation of being more difficult than in well aligned or varus knee, and there is no management consensus. Results on a continuous series of 100 TKAs on valgus knee were compared to the literature data, to define surgical strategy adapted to the various types of valgus knee

Is it dangerous? The role of an emotional visual search strategy and threat‐relevant training in the detection of guns and knives

Counter‐terrorism strategies rely on the assumption that it is possible to increase threat detection by providing explicit verbal instructions to orient people's attention to dangerous objects and hostile behaviours in their environment. Nevertheless, whether verbal cues can be used to enhance threat detection performance under laboratory conditions is currently unclear. In Experiment 1, student participants were required to detect a picture of a dangerous or neutral object embedded within a visual search display on the basis of an emotional strategy ‘is it dangerous?’ or a semantic strategy ‘is it an object?’. The results showed a threat superiority effect that was enhanced by the emotional visual search strategy. In Experiment 2, whilst trainee police officers displayed a greater threat superiority effect than student controls, both groups benefitted from performing the task under the emotional than semantic visual search strategy. Manipulating situational threat levels (high vs. low) in the experimental instructions had no effect on visual search performance. The current findings provide new support for the language‐as‐context hypothesis. They are also consistent with a dual‐processing account of threat detection involving a verbally mediated route in working memory and the deployment of a visual template developed as a function of training

Naissance d'un réseau gazier à Paris au XIXe siècle : distribution gazière et éclairage

[eng] Abstract : The gradual growth of parisian gas network in the ninetheenth century results from an underground and elaborate system. It has carried out public and private consumption of light and energy. This development went with an efficacious trading policy. Monopoly to lay down pipes has given to six companies in 1839, which became one firm in 1855. This fact has guaranted uniformity of this network. Many innovations are born to prevent technical problems owing to the growth. So, savings have been realized with research of cheaper materials and gaz-appliances. Moreover, understanding of physical principles have been improved. The quality of parisian light, especially with incandescent gas burner during the 1890', and density of street-lamps, more than 50 000 gas burner early in this century, prove main place which has been taken by gas in urban fittings of the ninetheenth century. [fre] Résumé : L'extension progressive d'un réseau de distribution de gaz à Paris au XIXe siècle résulte d'un maillage souterrain complexe, pour satisfaire la demande publique et privée, d'éclairage puis d'énergie, soutenue par une efficace politique commerciale. L'unité du réseau fut garantie par le monopole de canalisation des rues, accordé en 1839, pour des quartiers séparés, à six compagnies qui n'en formèrent plus qu'une en 1855. Confrontée aux problèmes techniques nés d'une croissance constante, la livraison du gaz obligeait à l'innovation. Des économies d'échelle ont ainsi été réalisées par la recherche de matériaux et d'appareils moins coûteux et par l'application d'une connaissance élaborée des principes physiques de ce réseau. Les progrès de l'éclairage public parisien, en qualité, avec la mise au point de l'éclairage à incandescence à partir de la décennie 1890, et en quantité, avec plus de 50 000 becs installés à la Belle Epoque, ont validé l'entreprise d'un tel réseau. La sanction commerciale qui a ratifié l'utilité de ces investissements confirme ainsi le rôle essentiel du gaz dans les aménagements urbains du siècle passé.

Rapport de mission en URSS, 19 Mai-2 juin 1981

[Notes_IRSTEA]car. bibl. sch.Les objectifs de cette mission étaient de faire le point sur l'élevage des esturgeons dans la région de la mer d'Azov et plus particulièrement dans le détroit de la Volga. Il est aussi question d'autres espèces, les recherches soviétiques portant sur ces autres espèces

Historic Overview of the European Sturgeon Acipenser sturio in France: Surveys, Regulations, Reasons for the Decline, Conservation, and Analysis: chap. 20

International audienceThis chapter deals with an historical overview of sturgeon fishery in France and with preservation and conservation issues. It includes conclusions and recommendations of the many scientific surveys, which have almost always been neglected. The cause of the decline in the population, fishery regulations, and the deterioration of the environment are described in detail. Proposals for the preservation and conservation of the species from the late 1970s on are briefly presented. The subsequent three-leg strategy is described: (1) the necessity to improve our knowledge of the biology of the remaining population, (2) the inevitable restocking programme to sustain the population, and (3) the need to use another sturgeon species as a biological model to acquire experience on life-cycle characteristics and to develop methods of artificial reproduction for subsequent application to Acipenser sturio. Conservation measures, both in situ and ex situ, are summarised. The analysis highlights the absence of (1) a resource-oriented fishery policy, and (2) measures to preserve biodiversity

Reproduction of the cultured brood fish: chap. 32

International audienceThis chapter describes the last management procedure applied to the brood fish. There are five steps, from the staging of sexual maturation advancement to the embryogenesis survey, i.e., in the last 2 months prior to spawning. Results are reported for the few oldest fish (born between 1981 and 1988 in the wild), composed mainly of males (only one female) that have been reconditioned, and the two youngest year classes (1994 and 1995). The oldest males exhibited very heterogeneous maturation figures, with a 2-year maturation occurring most frequently. Partial maturations in several females are reported, possibly due to inappropriate rearing conditions, namely temperature regime, which was later changed. Precocious reproductive successes were obtained with 13-year-old males and females whatever the year class of younger fish. There are suggestions of a 2-year recurring cycle in females. New indications are given for improving the prediction power of the in vitro maturation test