Retour d'expérience du démantèlement du barrage de Kernansquillec

National audienceKernansquillec dam in French Britany has been demolished in 1996. It was a multiple arch dam, 75-year-old, 15 m high , with a reservoir capacity of 400 000 m3. Due to the poor condition of the dam, risks involved downstream, and lack of an operator after the end of the concession, the Prefet decided the dam demolition. Management of the sediments, representing 50% of the reservoir capacity was achieved without interrupting water intakes for domestic water supply and fishfarming, situated few hundred meters downstream from the dam. The solution combined: hydrodredging of 90 000 m3 of sediments to restore the old river bed in the reservoir; in situ consolidation of the rest of the sediments, by slowly lowering the reservoir water level; construction of four little rockfill weirs downstream from the dam, for water decantation at the end of emptying. Total cost of the operation was just over 1 MA, including 0,6 MA for sediment management.Le barrage de Kernansquillec en Bretagne, vieux de 75 ans, a été démoli en 1996. C'était un barrage multi-voûtes de 15 m de hauteur et 400 000 m3 de capacité. Compte tenu de la vétusté de l'ouvrage, des risques induits pour l'aval et de l'absence de repreneur après la fin de concession, la décision de démolition a été prise par le préfet. Sa mise en oeuvre a été délicate du fait de l'envasement de la retenue et des enjeux liés à la consommation d'eau en aval. La vidange a pu être menée à bien avec succès en combinant : l'hydrocurage de 90 000 m3 de sédiments de façon à restaurer l'ancien lit de la rivière ; la consolidation en place des sédiments restants par un abaissement très lent du plan d'eau ; la construction de quatre seuils en enrochements en aval du barrage pour la décantation des sédiments en fin de vidange. Le coût total de l'opération fut d'un peu plus de 1 MA, dont 0,6 MA pour le seul poste de gestion des sédiments

Demographic and physiological signals of reproductive events in humpback whales on a southwest pacific breeding ground

The field of marine mammal conservation has dramatically benefited from the rapid advancement of methods to assess the reproductive physiology of individuals and populations from steroid hormones isolated from minimally invasive skin-blubber biopsy samples. Historically, this vital information was only available from complete anatomical and physiological investigations of samples collected during commercial or indigenous whaling. Humpback whales (Megaptera novaeangliae) are a migratory, cosmopolitan species that reproduce in warm, low-latitude breeding grounds. New Caledonia is seasonally visited by a small breeding sub-stock of humpback whales, forming part of the endangered Oceania subpopulation. To better understand the demographic and seasonal patterns of reproductive physiology in humpback whales, we quantified baseline measurements of reproductive hormones (progesterone – P4, testosterone - T, and 17β-estradiol – E2) using an extensive archive of skin-blubber biopsy samples collected from female humpback whales in New Caledonia waters between 2016-2019 (n = 194). We observed significant differences in the P4, T, and E2 concentrations across different demographic groups of female humpback whales, and we described some of the first evidence of the endocrine patterns of estrus in live free-ranging baleen whales. This study is fundamental in its methodological approach to a wild species that has a global distribution, with seasonally distinct life histories. This information will assist in monitoring, managing, and conserving this population as global ecological changes continue to occur unhindered.Peer reviewe

Governance traditions and narratives of public sector reform in contemporary France.

This article explores the basic traditions of governance in contemporary France and the narratives of public sector reform associated with them. It should be stressed right from the outset that this article does not aim to describe the set of public sector reforms that have been implemented in France in the last ten years or so. Instead, the aim is to demonstrate the similarities and differences between the narratives of the left and the right with regard to these reforms and to show how these narratives help to explain the types of reform that have been enacted. The basic argument is that there is a certain commonality to both the left and the right with regard to their narratives of public sector reform. At the same time, though, there are differences of emphasis both within each tradition and between the two main traditions themselves. Except where indicated, all translations are the author's own

Seasonal Spatial Segregation in Blue Sharks (Prionace glauca) by Sex and Size Class in the Northeast Pacific Ocean

Aim: Animal tracking can provide unique insights into the ecology and conservation of marine species, such as the partitioning of habitat, including differences between life history stages or sexes, and can inform fisheries stock assessments, bycatch reduction and spatial management such as dynamic management. Location: Northeast Pacific Ocean. Methods: We used satellite tracking data from 47 blue sharks (Prionace glauca) from the Northeast Pacific to determine movements and home range along the west coast of North America, and sex–size class (immature females, mature males) specific habitat preferences using boosted regression trees. Using a suite of static and dynamic environmental variables, we determined distribution and habitat preferences across summer and fall for each sex–size class. Results: We found that there was spatial segregation between sex–size classes particularly in the summer months with immature females found largely north of 33°N, and males south of 35°N. In fall, females travelled south, resulting in an overlap in distributions south of 37°N. Sea surface temperature (SST), latitude and longitude were top predictors. However, immature females and adult males demonstrated unique habitat preferences including SST, with immature females preferring cooler temperatures (SST \u3c 15°C) than adult males in summer, and a broader band of SST than adult males in fall. All models performed well, explaining 50%–67% of deviance, and 23%–41% of deviance when predictions were cross‐validated. Main conclusions: We provide first insights into coastal movements and habitat preferences of blue sharks in the Northeast Pacific. We found that immature females undergo a seasonal southward migration in this more coastal habitat, similar to patterns observed in the North Atlantic. We also found some overlap between adult males and immature females in fall months, suggesting the importance of more coastal habitat in managing this species, particularly in determining population structure for blue shark stock assessments, and reducing blue shark bycatch

EPIdemiology of Surgery-Associated Acute Kidney Injury (EPIS-AKI) : Study protocol for a multicentre, observational trial

More than 300 million surgical procedures are performed each year. Acute kidney injury (AKI) is a common complication after major surgery and is associated with adverse short-term and long-term outcomes. However, there is a large variation in the incidence of reported AKI rates. The establishment of an accurate epidemiology of surgery-associated AKI is important for healthcare policy, quality initiatives, clinical trials, as well as for improving guidelines. The objective of the Epidemiology of Surgery-associated Acute Kidney Injury (EPIS-AKI) trial is to prospectively evaluate the epidemiology of AKI after major surgery using the latest Kidney Disease: Improving Global Outcomes (KDIGO) consensus definition of AKI. EPIS-AKI is an international prospective, observational, multicentre cohort study including 10 000 patients undergoing major surgery who are subsequently admitted to the ICU or a similar high dependency unit. The primary endpoint is the incidence of AKI within 72 hours after surgery according to the KDIGO criteria. Secondary endpoints include use of renal replacement therapy (RRT), mortality during ICU and hospital stay, length of ICU and hospital stay and major adverse kidney events (combined endpoint consisting of persistent renal dysfunction, RRT and mortality) at day 90. Further, we will evaluate preoperative and intraoperative risk factors affecting the incidence of postoperative AKI. In an add-on analysis, we will assess urinary biomarkers for early detection of AKI. EPIS-AKI has been approved by the leading Ethics Committee of the Medical Council North Rhine-Westphalia, of the Westphalian Wilhelms-University Münster and the corresponding Ethics Committee at each participating site. Results will be disseminated widely and published in peer-reviewed journals, presented at conferences and used to design further AKI-related trials. Trial registration number NCT04165369

Dual-Plane Correlation for Three-Dimensional Particle Image Velocimetry on Planar Domains

Particle Image Velocimetry (PIV) is increasingly used to investigate unsteady flow velocity fields instantaneously. Thistechnique allows the recording of a complete velocity field in a plane of the flow within microseconds. In PIV the velocity vector field is usually determined by subdividing the recordings into small interrogation areas and employing particle tracking algorithms or statistical evaluation techniques. The method described in this paper is based onthe spatial cross-correlation of particle images stored on separate frames of each exposure. It is expanded by the analysis of the correlation peak heights. The correlation value depends on the portion of paired particle images, which itself depends on the out-of-plane velocity component, but also on other parameters such as background light, varying image size and number, loss of pairs dueto in-plane motion. To avoid problems arising from these other influences, images from a displaced light sheet plane,

Use of super-concepts to customize electronic medical records data display

International audienc

Social Structure, Habitat Use and Injuries of Indo-Pacific Bottlenose Dolphins (Tursiops aduncus) Reveal Isolated, Coastal, and Threatened Communities in the South Pacific

Understanding population structure and habitat use of poorly known cetacean species is a first step toward scientifically informed management decisions. In the southern range of New Caledonia (South Pacific), a long-term dataset of Indo-Pacific bottlenose dolphins (Tursiops aduncus) encounters primarily during winter seasons 1997 to 2019 (473 group observations) was used to assess social structure, habitat use and potential threats. A total of 338 individuals were photographically identified, forming three distinct communities in the south-west lagoon, the south lagoon and the Isle of Pines. Mark-recapture histories revealed that the three communities were weakly connected and might be considered as independent management units. Suitable habitats were estimated with presence-only distribution models relative to topographic and seabed substrate predictors. Habitat suitability increased with proximity to coasts or reefs, at shallow depth, and over muddy bottom. These habitats had various levels of protection and were used by humans, mostly in the south-west lagoon. External injuries were interpreted to determine natural interactions and potential anthropogenic threats. The prevalence in injuries did not vary among the three areas. A substantial proportion of injuries related to propeller hits was reported, representing a total of 16.7% (34 of 204) of all injuries observed on dolphins. The three communities of Indo-Pacific bottlenose dolphins revealed in the southern part of New Caledonia are particularly vulnerable due to their insularity, their coastal habitat use and the low levels of connectivity found among them. In a context of increasing maritime traffic, fishing and recreational activities, this study provides a useful baseline to the urgent assessment of the conservation status of dolphins in New Caledonia

Horizontal and vertical movements of humpback whales inform the use of critical pelagic habitats in the western South Pacific

Humpback whales (Megaptera novaeangliae) are known for their nearshore distribution during the breeding season, but their pelagic habitat use patterns remain mostly unexplored. From 2016 to 2018, 18 humpback whales were equipped with depth-recording satellite tags (SPLASH10) to shed light on environmental and social drivers of seamount association around New Caledonia in the western South Pacific. Movement paths were spatially structured around shallow seamounts (80 m, max 616 m) were also recorded (11.5%), including by maternal females. Deep dives often occurred in series and were characterized by U-shapes suggesting high energy expenditure. This study provides new insights into the formerly overlooked use of pelagic habitats by humpback whales during the breeding season. Given increasing anthropogenic threats on deep sea habitats worldwide, this work has implications for the conservation of vulnerable marine ecosystems