15,848 research outputs found

    Spin and magnetism in old neutron stars

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    The thermal, spin and magnetic evolution of neutron stars in the old low mass binaries is first explored. Recycled to very short periods via accretion torques, the neutron stars lose their magnetism progressively. If accretion proceeds undisturbed for 100 Myrs these stars can rotate close to break up with periods far below the minimum observed of 1.558 ms. We investigate their histories using population synthesis models to show that a tail should exist in the period distribution below 1.558 ms. The search of these ultrafastly spinning neutron stars as pulsars can help discriminating among the various equations of state for nuclear matter, and can shed light into the physics of binary evolution. The evolution of isolated neutron stars in the Galaxy is explored beyond the pulsar phase. Moving through the tenuous interstellar medium, these old solitary neutron stars lose their rotational energy. Whether also their magnetism fades is still a mystery. A population synthesis model has revealed that only a tiny fraction of them is able to accrete from the interstellar medium, shining in the X-rays. There is the hope that these solitary stars will eventually appear as faint sources in the Chandra sky survey. This might give insight on the long term evolution of the magnetic field in isolated objects.Comment: 28 pages, 11 PostScript figures. To be published in "Physics of Neutron Star Interiors" (Lecture Notes in Physics), ed. D. Blaschke, N.K. Glendenning and A. Sedrakian (Springer, 2001

    Transcriptomic effects of the non-steroidal anti-inflammatory drug Ibuprofen in the marine bivalve Mytilus galloprovincialis Lam

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    The transcriptomic effects of Ibuprofen (IBU) in the digestive gland tissue of Mytilus galloprovincialis Lam. specimens exposed at low environmental concentrations (250 ng L-1) are presented. Using a 1.7 K feature cDNA microarray along with linear models and empirical Bayes statistical methods 225 differentially expressed genes were identified in mussels treated with IBU across a 15-day period. Transcriptional dynamics were typical of an adaptive response with a peak of gene expression change at day 7 (177 features, representing about 11% of sequences available for analysis) and an almost full recovery at the end of the exposure period. Functional genomics by means of Gene Ontology term analysis unraveled typical mussel stress responses i.e. aminoglycan (chitin) metabolic processes but also more specific effects such as the regulation of NF-kappa B transcription factor activity. (C) 2016 Elsevier Ltd. All rights reserved

    A preliminary phylogeographic study of Flavopunctelia and Punctelia inferred from rDNA ITS-sequences

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    A preliminary phylogeny of the genera Flavopunctelia and Punctelia is presented. Genus and species delimitations have been investigated using ITS rDNA-sequencing of populations from different continents. Current genus delimitations of Flavopunctelia, Punctelia and Parmelia are confirmed and the species status of recently resurrected Punctelia ulophylla is confirmed. The status of three cryptic species, Flavopunctelia soredica, Punctelia perreticulata and P. stictica is discussed. Flavopunctelia borrerioides and Punctelia perreticulata are reported from China for the first time.Esitatakse perekondade Flavopunctelia ja Punctelia esialgne fülogeneesi rekonstruktsioon. Perekondade ja liikide eraldamist on uuritud erinevatelt kontinentidelt pärinevate populatsioonide ITS rDNA sekventside alusel. Senine perekondade Flavopunctelia, Punctelia ja Parmelia piiritlemine on leidnud kinnitust, samuti liigi Punctelia ulophylla staatus. Arutletakse kolme krüptilise liigi, Flavopunctelia soredica, Punctelia perreticulata ja P. stictica staatuse üle. Teatatakse liikide Flavopunctelia borrerioides ja Punctelia perreticulata esmasleidudest HiinasFil: Thell, Arne. Lund University; SueciaFil: Herber, B.. Universitat Hamburg; AlemaniaFil: Aptroot, A.. Centraalbureau voor Schimmelcultures; Países BajosFil: Adler, Monica Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Feuerer, T.. Universitat Hamburg; AlemaniaFil: Kärnefelt, Ingvar. Lund University; Sueci

    Evidence of Program Quality and Youth Outcomes in the DYCD Out-of-School Time Initiative: Report on the Initiative's First Three Years

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    Examines New York City's progress in improving out-of-school-time program quality and serving more children and youth, participants' and parents' overall satisfaction with quality and accessibility, and links between programming, quality, and benefits

    Cysteine proteinase C1A paralog profiles correspond with phylogenetic lineages of pathogenic piroplasmids

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    Piroplasmid parasites comprising of Babesia, Theileria, and Cytauxzoon are transmitted by ticks to farm and pet animals and have a significant impact on livestock industries and animal health in tropical and subtropical regions worldwide. In addition, diverse Babesia spp. infect humans as opportunistic hosts. Molecular phylogeny has demonstrated at least six piroplasmid lineages exemplified by B. microti, B. duncani, C. felis, T. equi, Theileria sensu stricto (T. annulata, T. parva, and T. orientalis) and Babesia sensu stricto (B. bovis, B. bigemina, and B. ovis). C1A cysteine-proteinases (C1A-Cp) are papain-like enzymes implicated in pathogenic and vital steps of the parasite life cycle such as nutrition and host cell egress. An expansion of C1A-Cp of T. annulata and T. parva with respect to B. bovis and B. ovis was previously described. In the present work, C1A-Cp paralogs were identified in available genomes of species pertaining to each piroplasmid lineage. Phylogenetic analysis revealed eight C1A-Cp groups. The profile of C1A-Cp paralogs across these groups corroborates and defines the existence of six piroplasmid lineages. C. felis, T. equi and Theileria s.s. each showed characteristic expansions into extensive families of C1A-Cp paralogs in two of the eight groups. Underlying gene duplications have occurred as independent unique evolutionary events that allow distinguishing these three piroplasmid lineages. We hypothesize that C1A-Cp paralog families may be associated with the advent of the schizont stage. Differences in the invertebrate tick host specificity and/or mode of transmission in piroplasmid lineages might also be associated with the observed C1A-Cp paralog profiles

    Gestion des connaissances : préambule à un portrait

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    Pour des raisons de performance, innovation ou compétitivité, les connaissances sont devenues une ressource de première importance dans les organisations de l’économie du savoir. Gérer les connaissances explicites et tacites représente une stratégie ayant ses propres concepts, méthodes, outils, qui attirent l’attention des spécialistes. En appliquant une analyse à un corpus d’articles scientifiques, cette étude se propose d’identifier les domaines traitant ou mettant en application la gestion des connaissances, afin de dresser un inventaire de ses champs d’étude et/ou d’application et contribuer ainsi à une meilleure compréhension de ses bénéfices. Ce texte présente des résultats préliminaires : douze domaines d’étude identifiés comme abordant la gestion des connaissances, à comparer aux résultats de la deuxième étape de la recherche (en cours), pour finalement élaborer un portrait de la gestion des connaissances et des aires d’études reliées.By reason of performance, innovation or competitiveness, knowledge has become an important resource for organisations in the knowledge economy. Managing the explicit and the tacit knowledge represents a strategy with its own concepts, methods, and tools, which draws the attention of specialists. Through an analysis on a corpus of scientific articles, this study aims to identify those fields related to, or utilizing knowledge management. The objective of this task is to draft an inventory of study fields and of the various applications of managing knowledge, thus to contribute to a better understanding of its benefits. This paper sums up the preliminary results of this two-part analysis : twelve fields have been identified as bearing an interest in knowledge management; they will be compared to the results obtained in the second part of the analysis (in progress), in order to work out a portrait of knowledge management and its related study areas

    Microscopic Entropy of the Black Ring

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    A surprising new seven-parameter supersymmetric black ring solution of five-dimensional supergravity has recently been discovered. In this paper, M-theory is used to give an exact microscopic accounting of its entropy.Comment: 5 pages; v2: References and acknowledgements adde
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