208 research outputs found

    Bibliothèques territoriales et économie locale du livre

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    Mémoire de fin d\u27étude du diplôme de conservateur, promotion DCB18, portant sur le rôle des bibliothèques dans la chaîne du livre

    Management plan to save the eel. Optimising the design and management of installations

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    The European eel was until recently an abundant species in most European freshwaters, but its numbers have fallen sharply since the 1970s and 1980s. The causes of the rapid decline, which now threatens the very existence of the species, are clear for the most part and include fishing, poor quality of water and habitats, fragmentation of rivers by weirs and dams, and death in hydroelectric turbines. To meet the restocking goals set by the European Union (EU), France has initiated a management plan addressing each of the factors responsible for the decline of the species. Concerning river obstacles and turbines, the Ecology ministry launched an R&D programme bringing together a number of partners, including Ademe, Onema and five hydroelectric companies, namely Compagnie nationale du Rhône, EDF, France Hydro Electricité, GDF Suez and Société hydroélectrique du Midi. The programme, managed by a steering committee comprising the partners mentioned above and placed under the responsibility of the Ecology ministry, targeted a number of operational goals that resulted in the development and testing of technical solutions designed for rapid implementation in the field. All programme results were presented on 28 and 29 November 2011 at the feedback symposium which brought together 160 persons, including researchers, water managers, associations and hydroelectric companies

    Plan de sauvegarde de l'anguille. Quelles solutions pour optimiser la conception et la gestion des ouvrages ?

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    Hier encore très répandue dans plupart des eaux douces d’Europe, l'anguille européenne connaît une régression rapide depuis les années 1970-1980. Les causes de ce déclin brutal, qui menace désormais la pérennité de l’espèce, sont pour l'essentiel connues : prélèvements par la pêche, dégradation de la qualité des eaux et des habitats, fragmentation des rivières sous l'effet des seuils et barrages et mortalités lors des passages dans les turbines hydroélectriques. Pour répondre aux objectifs de restauration des stocks fixés par l'Union européenne, la France s'est engagée dans un plan de gestion visant à agir sur chacun des facteurs de déclin de l'espèce. Sur le volet «ouvrages», le Ministère en charge de Développement durable a initié un programme de recherche & développement multi-partenarial, réunissant l'Ademe, l'Onema et cinq acteurs français de l’hydoéléctricité : Compagnie Nationale du Rhône, EDF, France Hydro Électricité, GDF Suez, Société hydroélectrique du Midi. Résolument opérationnel, ce programme, encadré par un comité de pilotage rassemblant les acteurs précédemment cités et placé sous l'autorité du MEDDE, s'est traduit par la mise au point et le test de solutions techniques en vue d’une mise en oeuvre directe sur les territoires. L'ensemble de ces acquis ont été présentés lors d’un colloque les 28 et 29 novembre 2011 qui a rassemblé près de 160 personnes : scientifiques, gestionnaires de l’eau, associations, producteurs d’hydroélectricité

    Les techniques de contrôle des passes à poissons

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    Behaviour and passage of European silver eels (Anguilla anguilla) at a small hydropower plant during their downstream migration

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    Between 2004 and 2007, 116 downstream migrant silver eels (Anguilla anguilla) were monitored at a hydropower plant on the Gave de Pau river in South-West France using radio and PIT telemetry. The objectives of the study were: (i) to determine the environmental conditions when eels arrived and passed the facility; (ii) to determine the rate of eel escapement (passage other than via the turbines); (iii) to describe the behaviour of eels faced with the intake structure and the permeability of the intake trashracks for the different sizes of eel; and (iv) to determine whether surface bypasses originally designed for salmon could be effective for eels. Five types of behaviour of silver eels in the forebay and at the plant intakes were identified. The study showed the key factor influencing both eel behaviour and the route taken through the plant was variation in river discharge. Escapement rate was related to eel length and the spill flow to river flow ratio, which could be described by a logistic regression model. The surface bypasses originally designed for salmon were found to aid downstream eel migration significantly. At velocities < 0.40 m·s−1, no eels, even the largest, for which the racks are a physical barrier, were found impinged on the trashracks

    Migration pattern of silver eel (Anguilla anguilla, L.) in an obstructed river system.

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    The downstream migration of European silver eels in the River Frémur was examined to determine the potential effects of the numerous migration barriers that exist on waterways in western France. The Frémur has a 14 m high dam which creates a 3 · 106 m3 water supply reservoir, 6 km from tidal limit. Based on 8-year records (1996–2004) of migrant silver eels captured in a Wolf trap located about 1 km below the dam, the influence of this dam on the migration was examined. These records indicate that 91% of silver eels were captured when the dam was overtopped (i.e. when the water reservoir was full). The timings of the overflow periods varied greatly between years mainly because they are function of the duration of the filling period which in turn is dependent on the level of summer water abstraction and annual hydrological conditions. Consequently, migration periods occurred at variable dates (between November and April) which is late in comparison with nonobstructed European river systems (generally between August and December). During overflow periods the migration of silver eels increased markedly during rain events (increasing river flow). This indicates that flow flushes, are essential so that settled silver eels can orientate themselves and pass over the dam. The hypothesis of a ‘dam effect’ that could stop temporarily or permanently some of silver eels in the reservoir is discussed. Finally, the influence of the migration delays on the condition of silver eels is considered

    Thinking like a fish: a key ingredient for development of effective fish passage facilities at river obstructions

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    Worldwide, obstructions on watercourses have interfered with migratory pathways of fish species, reducing life‐cycle success and often eliminating diadromous fish species altogether from river basins. Over the last century, efforts to mitigate these effects were initially directed at developing fishways for upstream, high‐value migrant adult salmon. In more recent years, efforts have turned to developing fishways for other species. Results of past research suggest that the development of effective fishways requires biological knowledge of fish behaviour when encountering variable flows, velocity and turbulence, combined with hydraulic and civil engineering knowledge and expertise to develop facilities that provide ppropriate hydraulic conditions that fish will exploit. Further, it often requires substantial financial resources for biological and hydraulic testing as well as engineering design, particularly where prior knowledge of the behaviour of target fish species does not exist. Where biological or engineering knowledge (or both) is absent, development of effective passage facilities must take on a trial and error approach that will almost certainly require years to attain success. Evaluations of existing adult and juvenile fish passage facilities, where they have been carried out, suggest that migrant fish reject areas with hydraulic conditions they determine unsuitable. Even well designed fish ladders or nature‐like bypass channels for upstream migrants, even those with good attraction flows, will fail if incorrectly sited. Although progress has been made, developing successful installations for downstream migrants remains much more difficult, probably because downstream fish move with the flow and have less time to assess cues at entrances to any bypasses that they encounter

    Abscess Formation Following Spilled Gallstones During Laparoscopic Cholecystectomy

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    A review of the English literature concerning spilled gallstones during laparoscopic cholecystectomy is compared with one institution's experience of four cases during 1,726 laparoscopic cholecystectomies performed over a four-year period. Strategies regarding management and treatment are discussed
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