158 research outputs found

    EstaciĂłn de tratamiento de lodos - Orly (Francia)

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    The article describes the main problems facing the authors of the design, and the manner in which they have overcome them. The main feautures of the Station are — reception of mud from decantation plants, and preliminary concentration; — recuperation of alumina sulphate, by acid treatment, and decantation of acidified muds, and — treatment of muds with neutralizing agents and filtration in vacuum. Although It is too early to be certain, It appears the results so far obtained In this plant, perhaps unique in the world, are highly promising and indicate a positive development In the future.El artículo explica los problemas principales que se les han planteado a los autores del proyecto y cómo han tratado de resolverlos: - recepción de lodos procedentes de los decantadores y concentración preliminar; - recuperación del sulfato de alúmina por tratamiento al ácido con decantación de lodos acidificados; - tratamiento de lodos con neutralización y filtración en vacio. Aunque todavía es pronto, parece ser que los resultados obtenidos en esta instalación —tal vez la única del mundo— son muy alentadores y marcan un interesante camino a seguir

    Taille de la population d’Avahi laniger dans la réserve d’Ambodiriana-Manompana, Nord-est de Madagascar

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    Avahi laniger est le seul lémurien nocturne appartenant à la famille des Indriidae qui habite les forêts humides de l’est de Madagascar (Mittermeier et. al., 2010) dont une partie disparaît chaque année (exploitation du bois, pratique du «tavy» ou culture sur brûlis) (Beaucent and Fayolle, 2011; Lehman and Wright, 2000). La fragmentation et la destruction de leur habitat ainsi que la chasse menacent la survie de nombreuses espèces de lémuriens incluant celle de A. laniger (Jenkins et. al., 2011; Rakotondravony and Rabenandrasana, 2011; Anderson, Rowcliffe and Cowlishaw, 2007). Nous avons réalisé, entre fin Avril et Mai 2012, une étude de densité de la population de A. laniger au sein de l’aire protégée de Manompana-Ambodiriana afin d’estimer la taille de la population totale et de déterminer l’impact du projet de conservation menée par l’Association de Défense de la Forêt d’Ambodiriana (ADEFA) qui recherche l’évolution démographique à moyen terme de cette espèce."LABEX" TULIP: (ANR-10-LABX-41), fct fellowship: (SFRH/BD/64875/2009)

    The utility of existing passerine microsatellite markers for genetic studies in endangered species: as demonstrated for a critically endangered forest bird endemic to RĂ©union Island, the RĂ©union cuckooshrike (Coracina newtoni)

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    Genetic data are increasingly recognized for their utility in conservation programs. However, many endangered species belong to families that have been understudied. Due to the urgency of their conservation status it is important to quickly identify polymorphic microsatellite loci from available resources. We show for the Re´union Cuckoo shrike Coracina newtoni, that this strategy can be very useful. Using 110 passerine microsatellite primer sets we identified eighteen polymorphic loci and tested them in 25 C. newtoni individuals. Following a Bonferroni correction one pair of loci displayed linkage disequilibriu

    Neutron Stars in a Varying Speed of Light Theory

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    We study neutron stars in a varying speed of light (VSL) theory of gravity in which the local speed of light depends upon the value of a scalar field Ď•\phi. We find that the masses and radii of the stars are strongly dependent on the strength of the coupling between Ď•\phi and the matter field and that for certain choices of coupling parameters, the maximum neutron star mass can be arbitrarily small. We also discuss the phenomenon of cosmological evolution of VSL stars (analogous to the gravitational evolution in scalar-tensor theories) and we derive a relation showing how the fractional change in the energy of a star is related to the change in the cosmological value of the scalar field.Comment: 15 pages, 2 figures. Added solutions with a more realistic equation of state. To be published in PR

    The value of the spineless monkey orange tree (Strychnos madagascariensis) for conservation of northern sportive lemurs (Lepilemur milanoii and L. ankaranensis)

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    Tree hollows provide shelters for a large number of forest-dependent vertebrate species worldwide. In  Madagascar, where high historical and ongoing rates of deforestation and forest degradation are  responsible for a major environmental crisis, reduced availability of tree hollows may lead to declines in hollow-dwelling species such as sportive lemurs, one of the most species-rich groups of lemurs. The identification of native tree species used by hollow-dwelling lemurs may facilitate targeted management interventions to maintain or improve habitat quality for these lemurs. During an extensive survey of sportive lemurs in northern Madagascar, we identified one tree species, Strychnos madagascariensis (Loganiaceae), the spineless monkey orange tree, as a principal sleeping site of two species of northern sportive lemurs, Lepilemur ankaranensis and L. milanoii (Lepilemuridae). This tree species represented 32.5% (n=150) of the 458 sleeping sites recorded. This result suggests that S. madagascariensis may be valuable for the conservation of hollow-dwelling lemurs. De nombreux vertébrés forestiers à travers le monde trouvent refuge dans des cavités et des trous  d’arbres. À Madagascar, les taux de déforestation historiques et actuels sont responsables d’une crise environnementale majeure. Dans ce contexte, une disponibilité réduite d’arbres pourvus de cavités  pourrait entrainer le déclin des espèces dépendant de ces abris comme par exemple les lépilemurs, un des groupes de lémuriens les plus riches en espèces. L’identification des espèces d’arbres indigènes creusés de trous et utilisés par les lémuriens pourrait faciliter la mise en place d’actions de conservation ayant pour but de maintenir ou améliorer l’habitat de ces lémuriens. Au cours d’une étude réalisée dans le Nord de Madagascar, nous avons observé que Strychnos madagascariensis  (Loganiaceae) était   fréquemment utilisé comme site dortoir par les deux espèces de lépilemurs présentes, Lepilemur   ankaranensis and L. milanoii (Lepilemuridae). Cette espèce d’arbre concernait 32,5% (n = 150) des 458  sites dortoirs enregistrés. Ce résultat suggère que S. madagascariensis pourrait être important pour la  conservation des lémuriens dépendant de sites dortoirs

    On spontaneous scalarization

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    We study in the physical frame the phenomenon of spontaneous scalarization that occurs in scalar-tensor theories of gravity for compact objects. We discuss the fact that the phenomenon occurs exactly in the regime where the Newtonian analysis indicates it should not. Finally we discuss the way the phenomenon depends on the equation of state used to describe the nuclear matter.Comment: 41 pages, RevTex, 10 ps figures, submitted to Phys. Rev.

    Estimation des densités et tailles de population du Microcèbe Roux du Nord de (Microcebus tavaratra) dans la région Loky-Manambato (Daraina)

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    La région Loky-Manambato dans le Nord de Madagascar, est connue pour abriter le propithèque à couronne dorée (Propithecus tattersalli), un lémurien emblématique et endémique de la région. Néanmoins cette région composée d’une dizaine de fragments forestiers de taille moyenne et encore relativement peu étudiés, abrite aussi le microcèbe roux du nord (Microcebus tavaratra). Malgré la gestion des forêts de cette région par l’ONG Fanamby depuis 2005, aucune étude n’avait encore été menée dans chacun des fragments forestiers de la région pour déterminer la présence et quantifier la taille des populations de microcèbes de chacun d’entre eux. Lors de notre étude nous avons tenté d’estimer les densités et les tailles des populations de M. tavaratra dans neuf des dix principaux fragments forestiers de la région. Dans ce but nous avons utilisé la méthode de «line transect distance-sampling». Nos résultats montrent que les densités de microcèbes sont relativement élevées, et varient de 28 à 325 ind/km² entre fragments forestiers de la région. Desétudes plus approfondies des données collectées seront nécessaires pour déterminer les variables environnementales responsables des différences de densité observées.FCT grant: (SFRH/BD/64875/2009); l’Institut Français de la Biodiversité, GDRI Madagascar, “Laboratoire d’Excellence” (LABEX) TULIP: (ANR -10-LABX-41)

    Daraina sportive lemur (Lepilemur milanoii) density and population size estimates in most of its distribution range: the Loky-Manambato region.

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    The population of the Daraina sportive lemur (Lepilemur milanoii) is believed to be mostly confined to the Loky-Manambato region (Louis et al., 2006). Very little is known about L. milanoii and it is classified as “Data Deficient” by the IUCN (IUCN, 2013; Schwitzer et al., 2013). Despite the management of the area by the NGO Fanamby since 2005, no study had been conducted to determine the presence and the abundance of L. milanoii in the main forest fragments of the region. During the 2011 dry season we surveyed the ten main forest fragments of the Loky-Manambato region and estimated L. milanoii densities and population sizes using line transect distance sampling (Buckland, 2001) and the DISTANCE software (Thomas et al., 2010). The results suggest that sportive lemur densities are reasonably high in the region, but with important discrepancies between forest fragments, with densities ranging from 49.8 ind./km² in Antsaharaingy to 590.5 ind./km² in Ampondrabe. For the region Loky-Manambato we were able to estimate a population size of 52,000 individuals. This is the first estimate for the total population size and we argue that similar studies should be repeated to monitor environmental changes and anthropogenic pressures (hunting, deforestation, mining, etc.).FCT grant: (SFRH/BD/64875/2009); the Groupement de Recherche International (GDRI); "Laboratoire d’Excellence" (LABEX) entitled TULIP : (ANR-10-LABX-41); Rufford Small Grant Foundation grant: (10941-1)

    Survey of the critically endangered Perrier’s sifaka (Propithecus Perrieri) across most if its distribution range.

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    Propithecus perrieri (Perrier’s sifaka) is one of the most endangered lemur species due to its small and fragmented distribution range. Despite a Critically Endangered (CR) conservation and flagship species status, there are still many uncertainties regarding its actual distribution and its presence in some forests of its putative distribution range. We report the results of diurnal and nocturnal surveys carried out in 2012 across most forest fragments of its putative distribution range, namely the Ankarana National Park, the Analamerana Special Reserve and Andrafiamena-Andava-koera Protected Area. During our surveys the species was only observed in Andrafiamena and Analamerana protected areas.FCT fellowship: (SFRH/BD/64875/2009), Institut Français de la Biodiversité, the GDRI Madagascar, the “Laboratoire d'Excellence” (LABEX) entitled TULIP (ANR-10-LABX-41), Instituto Gulbenkian de Ciência, “Optimus Alive!” Biodiversity grant, The Rufford Small Grant for Nature Conservation: (ref. 10941-1), Département de Biologie Animale et Ecologie (D.B.A.E.), Faculté des Sciences, University of Mahajanga, the University of Antsiranana, and the Fanamby NGO (in particular S. Rajaobelina), Madagascar National Park, Analamerana Special Reserve, Ankarana National Park

    Micro- and Nanoplastics’ Effects on Protein Folding and Amyloidosis

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    A significant portion of the world's plastic is not properly disposed of and, through various processes, is degraded into microscopic particles termed micro- and nanoplastics. Marine and terrestrial faunae, including humans, inevitably get in contact and may inhale and ingest these microscopic plastics which can deposit throughout the body, potentially altering cellular and molecular functions in the nervous and other systems. For instance, at the cellular level, studies in animal models have shown that plastic particles can cross the blood-brain barrier and interact with neurons, and thus affect cognition. At the molecular level, plastics may specifically influence the folding of proteins, induce the formation of aberrant amyloid proteins, and therefore potentially trigger the development of systemic and local amyloidosis. In this review, we discuss the general issue of plastic micro- and nanoparticle generation, with a focus on their effects on protein folding, misfolding, and their possible clinical implications
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