"Silver" mode for the heavy Higgs search in the presence of a fourth SM family

We investigate the possible enhancement to the discovery of the heavy Higgs boson through the possible fourth SM family heavy neutrino. Using the channel h-> v4 v4->mu W mu W, it is found that for certain ranges of Higgs boson and v4 masses LHC could discover both of them simultaneously with 1 fb^-1 integrated luminosity

Variability of physiological brain perfusion in healthy subjects – A systematic review of modifiers. Considerations for multi-center ASL studies

Quantitative measurements of brain perfusion are influenced by perfusion-modifiers. Standardization of measurement conditions and correction for important modifiers is essential to improve accuracy and to facilitate the interpretation of perfusion-derived parameters. An extensive literature search was carried out for factors influencing quantitative measurements of perfusion in the human brain unrelated to medication use. A total of 58 perfusion modifiers were categorized into four groups. Several factors (e.g., caffeine, aging, and blood gases) were found to induce a considerable effect on brain perfusion that was consistent across different studies; for other factors, the modifying effect was found to be debatable, due to contradictory results or lack of evidence. Using the results of this review, we propose a standard operating procedure, based on practices already implemented in several research centers. Also, a theory of ‘deep MRI physiotyping’ is inferred from the combined knowledge of factors influencing brain perfusion as a strategy to reduce variance by taking both personal information and the presence or absence of perfusion modifiers into account. We hypothesize that this will allow to personalize the concept of normality, as well as to reach more rigorous and earlier diagnoses of brain disorders

Modelling the distribution of vulnerable skate from fisheries dependent data using imperfect detection

International audienceLittle is still known about the biology and ecology of many elasmobranchs which often inhibits species specific management measures from being implemented. The primary aim of this study was to improve the knowledge on the distribution and habitat use of the threatened and data deficient shagreen ray, Leucoraja fullonica, using fisheries dependent data. To model its distribution, we used Bayesian hierarchical modelling, taking into consideration imperfect capture from the non-random nature of fishing gear type and spatial autocorrelation. Our second objective was to identify the potential functional role of the high occurrence area by analysing spatial length segregation using a generalised additive mixed model. From five environmental variables, depth, distance to coast, and seabed sediment type were used to model its habitat. L. fullonica was found to mainly inhabit an area of high concentration between the southern Celtic Seas and the northern Bay of Biscay. Within this area, smaller individuals were found in the deeper south-western part and larger individuals in shallower waters, closer to the coast, suggesting ontogenetic shift or spawning migration. L. fullonica were mainly caught by bottom trawl fishing gears. The isolated habitat occupancy of this species may increase its vulnerability, particularly since high fishing pressure has been observed in this area. These results highlight the importance of fisheries-dependent data for data-poor species and provide valuable new information on its ecology when considering management or conservation measures at a species level

Heritability of morphological and architectural characters in three pear progenies

International audienc

Modelling the distribution of rare and data-poor diadromous fish at sea for protected area management

Anthropogenic pressures have resulted in declines in diadromous fish. Many diadromous fish which were commercially important are now threatened and protected. Little is known about their marine life history phases, and no observation-based Species Distribution Model exists for this group of species at sea. Yet, fisheries dependent and independent data could provide new insights into the distribution of diadromous fish at sea.We collated a database of 168 904 hauls from fisheries observer bycatch data and scientific fisheries surveys, from eastern Atlantic and Mediterranean waters. The distribution of eleven rare and data-poor diadromous fish (shads, lampreys, salmonids, the European eel, the thinlip mullet, smelt and the European flounder) were modelled. A Bayesian site occupancy model, that incorporates imperfect detection to account for repeat de-tections and non-detections, the non-random nature of fishing gear type and spatial autocorrelation was used. From the model outputs, we explored bycatch risk and the role of MPAs, required under the Marine Strategy Framework Directive and Habitat Directive and assessed.Diadromous fish were observed within relatively shallow coastal areas. Species specific gear bycatch trends were observed. Core distribution areas corresponded to their known water basin presence, indicating connec-tivity with their freshwater habitats. Numerous Habitat Directive Marine Protected Areas were found to be of relevance.Given the coastal distribution of these species, they are exposed to higher anthropogenic pressures from both terrestrial and marine environments. Risk of bycatch at sea for most species appears to be low. Nonetheless, for threatened individuals, even a small amount of bycatch may impact their populations, especially since mis-reporting is likely to be high. Differences in catchability between gears highlight potential benefits of limiting access of certain gears within protected areas to reduce bycatch

Suivi et estimation du flux d’échappement des anguilles argentées de la Loire fluviale de 2017 à 2019 et retour d’expériences sur le repeuplement.

L’objectif principal de ce travail est de comparer les méthodes de suivis de la dévalaison des anguilles argentées, l’indice d’abondance basé sur les analyses des captures de 4 pêcheries professionnelles au guideau et l’estimation des flux d’anguilles argentées par capture marquage recapture. Le second objectif est d’estimer, par le biais d’une pêcherie disposant d’une autorisation expérimentale, les effectifs et les caractéristiques des anguilles argentées migrant en dehors de la période réglementaire. Enfin, il s’agit d’estimer la proportion d’anguilles argentées provenant des opérations de repeuplement

Rapport du projet « MigrenMer » : Synthèse et valorisation des connaissances disponibles sur les migrateurs amphihalins en mer Rapport final

La France métropolitaine abrite une des plus grandes diversités de poissons migrateurs amphihalins à l’échelle européenne. Parmi ces espèces deux stratégies migratoires sont observées. Les espèces potamotoques (ou anadromes) réalisent leur reproduction en eaux douces et leur croissance dans le milieu marin. A l’inverse les espèces thalassotoques (ou catadromes) se reproduisent en mer et réalisent leur croissance en eau douce. Depuis déjà plusieurs décennies, les populations de poissons migrateurs s'effondrent, et ce déclin est commun à l'ensemble des espèces. Les pressions exercées tout au long du continuum terre-mer, en particulier celles induites par les activités anthropiques, contribuent à ce déclin. Malgré les directives et conventions visant à protéger ces espèces, la gestion de leur phase marine reste difficile en raison d'un manque de connaissances sur ce compartiment marin. Afin de combler ce déficit, le pôle pour la gestion des migrateurs amphihalins dans leur environnement (MIAME) a initié début 2019 le programme MigrenMer.Une base de données rassemblant l’ensemble des données scientifiques et commerciales disponible sur les amphihalins en mer a été consolidée. Les premières analyses révèlent une faible occurrence des espèces, avec des disparités interspécifiques marquées (https://halieut.agrocampus-ouest.fr/discardless_app/migrenmer/Atlas/). La base de données a également servi à développer des modèles de distribution d'espèces pour étudier la distribution des amphihalins à l’échelle de l’Atlantique Nord-Est. Un premier modèle intitulé hSDM a confirmé la distribution côtière des espèces, soulignant leur dépendance à ces habitats et la nécessité d’étudier leur vulnérabilité face aux pressions anthropiques dans ces zones. Dans ce sens, il semble primordial d’assurer la précision de ces prédictions à une fine échelle à des fins de gestion. Un cadre de modélisation appelée CMAP a été développé se basant sur la combinaison de plusieurs modèles. Les résultats mettent en lumière l'importance du réseau d'aires marines protégées (AMPs) pour la conservation des amphihalins, mais soulignent la nécessité d'ajustements pour couvrir l'ensemble du continuum d'habitats. Ces axes d’amélioration permettront d’optimiser la protection des poissons migrateurs amphihalins durant la phase marine de leur cycle de vie.Les données bancarisées dans le cadre de l’action MigrenMer ont également vocation à répondre aux objectifs de surveillance et d’évaluation des directives européennes (DHFF et DCSMM). Les développements réalisés (matrice interaction engins/espèces et modèles spatiaux de distribution en mer) ont permis de nourrir, dans le cadre de la DHFF, une analyse risque-pêche identifiant les secteurs à risque de capture accidentelle par les activités de pêche maritime professionnelle. Concernant le Descripteur 1 Biodiversité de la DCSMM, le développement d’indicateurs du Bon Etat Ecologique (BEE) des critères D1C2 (abondance des populations) et D1C4 (Distribution spatiale des population) et des autres critères (D1C1 et D1C3) n’a pas été possible car les données disponibles étaient insuffisantes. Des acquisitions de données et développements méthodologiques supplémentaires sont nécessaires pour répondre à l’ensemble de ces exigences. Afin d’identifier les actions à prioriser, un échange avec les gestionnaires a été organisé et les perspectives de travail nécessaires à une gestion intégrée de ces espèces sur le continuum terre/mer ainsi qu’à leur surveillance et évaluation pour les différentes directives, sont présentées

Hydro-morphological features and functional structure of fish assemblages mediate species isotopic niches in estuaries

International audienceDespite the popularity of stable isotope analysis (Carbon and Nitrogen), the drivers of species isotopic niches and their consequences on food web functioning remained poorly described, especially in estuaries. Here, we hypothesised that species niche characteristics are influenced by ecosystem hydro-morphological features and the functional structure of fish assemblages. The trophic niches of four fish species (Dicentrarchus labrax, Pomatoschistus minutus, Sprattus and Platichthys flesus) and overlap between them were compared during two consecutive autumns in eight estuarine ecosystems of the northeast Atlantic Ocean. Our findings demonstrated a relative steadiness of trophic positions of fish in estuaries, despite a high level of interspecific variability. The seabass generally occupied the higher trophic position, followed by the sand goby, while the flounder and sprat were at the lowest position in the food web. Species isotopic niches and overlap were mediated by some estuarine features, including estuary size and intertidal extent, but also by biotic interactions at the intra-and inter-specific levels, as reflected by the influence of fish abundance and functional diversity metrics. Our results support the statement that the intertidal area is a pivotal factor in regulating trophic interactions, by promoting niche partitioning and diversification of trophic resources between species. Moreover, niche size and dietary divergence of species decreased with increasing regularity of trophic strategies within assemblages, suggesting that species occupied more restricted trophic niches when they were less subjected to competition for the same food resources. These findings emphasize the importance of local conditions and the functional composition of assemblages in modulating the trophic resources consumed by fish in estuarine environments