1,721,073 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Evaluation of essential oils for their use in preventive animal complementation
No full textL’usage de la phytothérapie pour la prévention de pathologies récurrentes dans les élevages s’est récemment développé. Les huiles essentielles (HE) sont des extraits végétaux complexes, constituant une source d’alternatives de par leur composition chimique variée et d’intéressantes activités biologiques. Ce projet de thèse a été réalisé dans un contexte industriel, avec pour objectif principal la mise en évidence des propriétés des HE et de leurs mélanges par des méthodes in vitro. Les mélanges formés doivent permettre de cumuler les activités naturelles des HE dans les sphères respiratoires, digestives et immunitaires et dans la prévention des mammites. Une sélection en entonnoir intervient d’après une trame d’essais spécifiques à chaque sphère. L’HE de girofle, intégrée dans les mélanges, développe d’après différentes méthodes biochimiques de fortes activités antioxydantes et anti-inflammatoires. Les HE de cannelle et d’origan se sont illustrées pour leur capacité à inhiber le développement des pathogènes comme les bactéries sous forme planctonique ou de biofilm, les virus ou les parasites internes. Les effets sur le biofilm bactérien ont notamment été observés par microscopie confocale à balayage laser. Enfin la capacité de l’HE de girofle à moduler la réponse inflammatoire a été démontrée sur le modèle de macrophage RAW264.7. La phagocytose, l’expression de la nitroxyde synthase et la sécrétion d’interleukine-6 ont été suivis par criblage à haut débit associé à la microscopie à épifluorescence. La caractérisation des mélanges a abouti à la formulation des noyaux Respilor®, Digelor®, Immulor® et Mastilor®, testés in vivo et commercialisés par BioArmor.The use of phytotherapy for the prevention of livestock associated pathologies is increasing since recent years. Essential oils (EO) are complex plant extracts, forming a large source of alternatives due to their chemical diversity and interesting biological activities. This project, carried out over three years and anchored in an industrial context, aims to highlight the properties of EO and their blends using in vitro assays. The objective is to cumulate the natural properties of EO through their blending. The prevention of respiratory and digestive tract diseases, of mastitis and the promotion of the animals’ immunity are particularly targeted. A funnel selection takes place according to tests selected for their specificity to each area. Clove EO, integrated in the mixtures, develops according to different biochemical methods strong antioxidant and anti-inflammatory activities. EOs of cinnamon and oregano have been shown to inhibit the development of pathogens such as planktonic or biofilm embedded bacteria, viruses or internal parasites. The effects on the bacterial biofilm were especially measured using confocal laser scanning microscopy. Finally, the ability of clove EO to modulate the inflammatory response has been demonstrated on the RAW264.7 macrophage cells. Phagocytosis, the expression of Nitroxide synthase, and the secretion of interleukin-6 were followed by high content screening methods associated with epifluorescence microscopy. The characterization of the mixtures resulted in the formulation Respilor®, Digelor®, Immulor® and Mastilor®, four blends of EO tested in vivo and commercialized by BioArmor
Toward a better understanding of the symbiotic relationships in Rimicaris exoculata model
No full textLes sources hydrothermales océaniques profondes renferment des écosystèmes extrêmes, situés dans la zone abyssale des Océans. Dans ces environnements dépourvus de lumière, la production primaire est réalisée par la chimiosynthèse microbienne. Ces milieux sont colonisés par des espèces animales, dont la plupart vivent en associations plus ou moins fortes avec des micro-organismes. La crevette Rimicaris exoculata est une espèce hydrothermale endémique des sites de la Ride-Médio-Atlantique (MAR), qui domine la plupart des sites qu’elle colonise. Ce crustacé a pour particularité de posséder deux communautés symbiotiques : une située dans son céphalothorax hypertrophié et une inféodée à son tractus digestif. Tout d’abord, ce travail de thèse s’est concentré sur l’étude de la communication bactérienne (Quorum Sensing ou QS) au sein des communautés ectosymbiotiques de R. exoculata au cours de son cycle de mue et de vie. Ensuite, ce travail s’est focalisé sur l’identification d’un peptide antimicrobien (PAM), puis à rechercher sa fonction dans l'immunité et le contrôle des symbiotes chez Rimicaris exoculata. Ce travail a permis, d’une part, de confirmer la présence de deux gènes du QS (luxS et luxR) dans les communautés ectosymbiotiques de R. exoculata sur quatre sites hydrothermaux : Rainbow, TAG, Snake Pit et Logatchev. Ces gènes étant plus divergents que ceux de l'ARNr 16S, leur utilisation comme marqueurs génétiques biogéographiques pour retracer l'origine des individus est discuté. Ce travail a permis, d’autre part, d’identifier pour la première fois un PAM (sus nommé Re-crustin), chez un arthropode hydrothermal. Les données suggèrent une participation de ce PAM dans le contrôle de l’ectosymbiose. L’ensemble de ces travaux apporte de nouvelles hypothèses sur l’interaction entre les épibiontes du céphalothorax et la crevette Rimicaris exoculata.Deprived of light, the deep-sea hydrothermal vents are extremes ecosystems sustained by micobial chemosynthesis. These environments are colonized by animal species living in close relationships with these chemoautotrophic micro-organisms, eating them or establishing long term interactions with them, may they be trophic or not only. The shrimp Rimicaris exoculata is an endemic hydrothermal species of the Mid-Atlantic Ridge (MAR) sites. This crustacean represents the predominant macrofauna of some sites of the MAR. It lives in symbiotic association with two distinct microbial communities qualified as ectosymbiosis. One is located in its gill chamber and one in its gut. First, this work focused on the study of bacterial communication (Quorum Sensing or QS) within the ectosymbiontic communities during the molting and life cycles of R. exoculata. Then, we focused on an antimicrobial peptide (AMP) identification and search for its function in R. exoculata immunity and in controlling symbionts. Two QS genes (luxS and luxR) were identified in the R. exoculata ectosymbiontic community at different shrimp molt stages and life stages at the Rainbow, TAG, Snake Pit and Logatchev vent sites.As these genes are more divergent than that of 16S rRNA, they could be then used as biogeographical genetic markers tools to trace back the origin of individuals to a location or between locations along its life cycle. This work reports also the first description of an AMP in an extremophile arthropod (namely Recrustin). Data suggest a participation of this AMP in the control of the ectosymbiosis in Rimicarisexoculata. All this work provides new hypotheses wich are discussed in the manuscript, dealing with the interaction between symbionts and Rimicaris exoculata
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Biosynthesis and regulation of alterins expression, an antibiotic peptide family produced by marine Pseudoalteromonas bacteria
No full textL’exploration des propriétés anti-bactériennes du microbiote hémolymphatique des animaux marins a conduit à l’isolement de différentes souches de Pseudaolteromonas. Deux d’entre elles, isolées de l’hémolymphe d’huître creuse et nommée hCg-6 et hCg-42, produisent une famille de peptides antibactériens nommés altérines. Les altérines sont composées d’un cycle heptapeptidique cationique contenant des résidus d’acides aminés exotiques, lié à une chaîne hydrocarbonée. Dans le cadre de cette thèse, les travaux ont porté sur la caractérisation de la chimiodiversité des altérines et de leur mécanisme de biosynthèse. Nous avons mené une étude par UPLC-MS de la structure des altérines produites par les souches hCg- 6 et hCg-42 ainsi que par des souches isolées de l’hémolymphe d’huître plate, nommées hOe-66, hOe- 124 et hOe-125. Cette étude a révélé que la famille des altérines est composé a minima de 37 isoformes présentant des modifications au niveau de certains résidus d’acides aminés ainsi que sur la chaîne hydrocarbonée. Nous avons entamé une analyse des génomes des 5 souches qui a révélé que les souches Pseudoalteromonas hOe appartiennent à une nouvelle espèce de Pseudoalteromonas. Compte tenu de l’origine de ces bactéries, nous avons nommé cette nouvelle espèce Pseudoalteromonas ostreae. Pour élucider les voies de biosynthèse et de régulation de l’expression des altérines nous avons combiné des analyses génomiques, transcriptomiques et culturomiques. La voie de biosynthèse des alterines est non ribosomale et implique un BGC de 30 kb contenant (i) 2 gènes codant des Non Ribosomal Peptide Synthétases (NRPS), (ii) des gènes environnants codant des enzymes de biosynthèse des monomères non proteogéniques et un transporteur de peptide cyclique et (iii) des gènes homologues à ceux décrits dans les mécanismes de résistance aux polymyxines. L’étude du transcriptome a révélé que la production d’altérines est dépendante de la disponibilité en résidus d’acides aminés originaux. Ce travail de thèse ouvre des perspectives de recherches sur l’immunité des souches à leurs propres altérines.The exploration of antibacterial properties from hemolymph of marins animals leaded to the isolation of several Pseudoalteromonas strains. Two of them were isolated from Crassostrea gigas hemolymph, called hCg-6 and hCg-42 and produce an antibacterial peptide family called alterins. These alterins are composed of a cationic heptapeptidic cycle with uncommon residues and a fatty acyl chain.As part of this PhD, the work focused on alterins chemodiversity characterization and their biosynthesis mechanism.We led a study through UPLC-MS method on alterins produced by the 2 strains hCg-6 and hCg-42 and also3 other Pseudoalteromonas strains isolated from Ostrea edulis hemolymph, called hOe-66, hOe-124 and hOe-125. It revealed a family of at least 37 isoforms with modifications on specific residues and the fatty acyl chain. The genomic analysis of the 5 strains allowed the identification of a new Pseudoalteromonas species for the 3 hOe strains, called Pseudoalteromonas ostreae.In order to elucidate the alterins biosynthesis pathway and the regulation mechanisms, we combined genomic, transcriptomic and culturomic methods. The biosynthesis pathway of alterins is a non-ribosomal pathway and involve a 30 kb BGC composed of (i) 2 genes coding Non Ribosomal Peptide Synthetase(NRPS), (ii) genes coding a peptide cyclic transporter and enzymes for the biosynthesis of non proteogenic residues and (iii) genes sharing homologies with genes involved in the polymyxins resistance. The transcriptomic study revealed that the alterin production depends on the availability of unusual residues.This thesis opens research perspectives on strain immunity to their own alterins
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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