1,721,042 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Interactions between Spiroplasma citri and its insect vector Circulifer haematoceps : s .citri phosphoglycerate kinase : an actin-binding protein involved in the spiroplasma transmission by leafhoppers.
No full textSpiroplasma citri est un mollicute phytopathogène transmis de plante à plante par des cicadelles du genre Circulifer selon un mode persistant circulant-multipliant. Les franchissements de l’épithélium intestinal et des glandes salivaires sont basés sur un mécanisme d’endocytose/exocytose. Ce processus d’invasion met en jeu, au sein de complexes protéiques, des protéines bactériennes spécifiques qui reconnaissent des motifs déterminés présents à la surface des cellules eucaryotes. La recherche de protéines de l’insecte vecteur interagissant avec S. citri a notamment conduit à l’identification de l’actine. Cette interaction a pu être confirmée à la fois in vitro et in vivo. L’interaction de l’actine avec son partenaire chez S. citri, qui s’est avéré être la phosphoglycérate kinase (PGK), est impliquée dans l’internalisation du spiroplasme dans les cellules de l’insecte. La région minimale de liaison à l’actine de la PGK a également été déterminée.La réalisation d’un mutant de S. citri dépourvu de PGK a été entreprise avec le plasmide navette pGOT mais n’a pas permis la sélection de spiroplasmes mutés dans ce gène essentiel. Néanmoins, la recherche de l’évènement de recombinaison chez les clones obtenus a permis de mettre en évidence la mutation de deux gènes chez ces derniers.L'ensemble des protéines impliquées dans la transmission du spiroplasme, identifiées au préalable chez ce dernier, n’étant pas essentielle au cours de ce processus, une étude préliminaire des complexes multi-protéiques contenant plusieurs de ces protéines a été réalisée. L’identification de complexes impliquant à la fois la PGK, la P32 et les ScARPs pourrait permettre de mieux comprendre les mécanismes régissant la vection de S. citri par son insecte.Spiroplasma citri is a phytopathogenic mollicute transmitted from plant to plant by leafhoppers of the genus Circulifer in a persistent and propagative manner on condition to cross the intestinal and salivary glands barriers of the insect. These crossings are based on a endocytosis/exocytosis mechanism which involves bacterial protein complexes in order to recognize specific patterns on the surface of eukaryotic cells.Specific molecular interactions between S. citri proteins and those of C. haematoceps were investigated using far Western technology and had notably led to the identification of actin. This interaction has been confirmed both in vitro and in vivo. The interaction of actin with his partner in S. citri, which has been identified as the phosphoglycerate kinase (PGK), is involved in the internalization of spiroplasma into the insect cells. The minimal actin-binding region of PGK was also determined.The realization of a S. citri PGK mutant was carried out using the shuttle plasmid pGOT but the selection of spiroplasmas mutated in this essential gene failed. Nevertheless, findings in the localization of recombination events in S. citri chromosome, allowed us to identify mutations in two genes that could be tested in our experimental transmission system.The set of proteins involved in the spiroplasmal transmission, previously identified as non essential proteins in the invasion process, prompted us to study the role of multi-protein complexes containing several of these proteins. Identification of complexes involving both the PGK, the P32 and ScARPs should enable us to better understand mechanisms governing the transmission of S. citri by its insect
Interactions between Spiroplasma citri and its insect vector Circulifer haematoceps : s .citri phosphoglycerate kinase : an actin-binding protein involved in the spiroplasma transmission by leafhoppers.
No full textSpiroplasma citri est un mollicute phytopathogène transmis de plante à plante par des cicadelles du genre Circulifer selon un mode persistant circulant-multipliant. Les franchissements de l’épithélium intestinal et des glandes salivaires sont basés sur un mécanisme d’endocytose/exocytose. Ce processus d’invasion met en jeu, au sein de complexes protéiques, des protéines bactériennes spécifiques qui reconnaissent des motifs déterminés présents à la surface des cellules eucaryotes. La recherche de protéines de l’insecte vecteur interagissant avec S. citri a notamment conduit à l’identification de l’actine. Cette interaction a pu être confirmée à la fois in vitro et in vivo. L’interaction de l’actine avec son partenaire chez S. citri, qui s’est avéré être la phosphoglycérate kinase (PGK), est impliquée dans l’internalisation du spiroplasme dans les cellules de l’insecte. La région minimale de liaison à l’actine de la PGK a également été déterminée.La réalisation d’un mutant de S. citri dépourvu de PGK a été entreprise avec le plasmide navette pGOT mais n’a pas permis la sélection de spiroplasmes mutés dans ce gène essentiel. Néanmoins, la recherche de l’évènement de recombinaison chez les clones obtenus a permis de mettre en évidence la mutation de deux gènes chez ces derniers.L'ensemble des protéines impliquées dans la transmission du spiroplasme, identifiées au préalable chez ce dernier, n’étant pas essentielle au cours de ce processus, une étude préliminaire des complexes multi-protéiques contenant plusieurs de ces protéines a été réalisée. L’identification de complexes impliquant à la fois la PGK, la P32 et les ScARPs pourrait permettre de mieux comprendre les mécanismes régissant la vection de S. citri par son insecte.Spiroplasma citri is a phytopathogenic mollicute transmitted from plant to plant by leafhoppers of the genus Circulifer in a persistent and propagative manner on condition to cross the intestinal and salivary glands barriers of the insect. These crossings are based on a endocytosis/exocytosis mechanism which involves bacterial protein complexes in order to recognize specific patterns on the surface of eukaryotic cells.Specific molecular interactions between S. citri proteins and those of C. haematoceps were investigated using far Western technology and had notably led to the identification of actin. This interaction has been confirmed both in vitro and in vivo. The interaction of actin with his partner in S. citri, which has been identified as the phosphoglycerate kinase (PGK), is involved in the internalization of spiroplasma into the insect cells. The minimal actin-binding region of PGK was also determined.The realization of a S. citri PGK mutant was carried out using the shuttle plasmid pGOT but the selection of spiroplasmas mutated in this essential gene failed. Nevertheless, findings in the localization of recombination events in S. citri chromosome, allowed us to identify mutations in two genes that could be tested in our experimental transmission system.The set of proteins involved in the spiroplasmal transmission, previously identified as non essential proteins in the invasion process, prompted us to study the role of multi-protein complexes containing several of these proteins. Identification of complexes involving both the PGK, the P32 and ScARPs should enable us to better understand mechanisms governing the transmission of S. citri by its insect
Interactions protéines-protéines entre Spiroplasma citri et son insecte vecteur Circulifer haematoceps. Identification de protéines d'insectes potentiellement impliquées dans la transmission
No full textDiplôme : Master Recherch
Interactions protéines-protéines entre Spiroplasma citri et son insecte vecteur Circulifer haematoceps. Identification de protéines d'insectes potentiellement impliquées dans la transmission
No full textDiplôme : Master Recherch
Variations on the Author
Full text link“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
Full text linkWe 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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
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