1,721,203 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
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
Neutron diffraction for deciphering protein‐carbohydrate interactions involved in bacterial infection
No full textLes lectines sont des protéines omniprésentes qui peuvent lier les glucides de manière spécifique et réversible. La reconnaissance et l'adhésion à médiation par les hydrates de carbone sont des événements clés dans les premières étapes de l'interaction des bactéries pathogènes ou symbiotiques avec un hôte. Par exemple, Pseudomonas aeruginosa est une bactérie opportuniste qui provoque une infection pulmonaire mortelle chez les patients atteints de mucoviscidose. Photorhabdus laumondii vit en relation symbiotique avec les nématodes et participe aux activités insecticides de ces vers. Les deux bactéries produisent plusieurs lectines, c'est-à-dire des récepteurs de glycanes, qui sont spécifiques aux glycoconjugués de l'hôte.Le but de cette thèse de doctorat était d'utiliser la cristallographie des protéines neutroniques pour fournir des informations sur les interactions entre lectines et glucides. Les lectines PLL et LecB spécifiques au fucus de Photorhabdus laumondii et Pseudomonas aeruginosa, respectivement, ont été choisies comme objet de notre étude. Une partie unique de la thèse a été la production in vivo d'un monosaccharide perdeutéré, le L-fucose, en utilisant des souches génétiquement modifiées de bactéries E. coli conçues par le Dr Eric Samain à l'institut CERMAV de Grenoble. Le fucose perdeutéré a été produit, purifié et caractérisé biophysiquement avec succès. Il a été utilisé comme ligand pour les essais de cristallisation des lectines PLL et LecB.Trois structures neutroniques ont été résolues dans le cadre de cette thèse. Deux structures de la lectine PLL de P. laumondii, à la fois sous forme apo et sous forme de ligand, et une structure de la lectine LecB de P. aeruginosa dans le complexe avec le fucose perdeutéré.Les résultats obtenus dans cette thèse ont donné lieu à une publication parue, une soumise et une en préparation qui font tous partie de ce manuscrit.Lectins are ubiquitous proteins that can reversibly and specifically bind to carbohydrates. Carbohydrate-mediated recognition and adhesion are key events in the early steps of the interaction of pathogenic or symbiotic bacteria with a host. For example, Pseudomonas aeruginosa is an opportunistic bacterium that causes lethal lung infection in cystic fibrosis patients. Photorhabdus laumondii lives in a symbiotic relationship with nematodes and is involved in insecticidal activities of these worms. Both bacteria produce several lectins, i.e. glycan receptors, which are specific for the host glycoconjugates.The aim of this PhD thesis was to use neutron protein crystallography to provide insights into lectin-carbohydrate interactions involved in bacterial infection. Fucose-specific lectins PLL and LecB from Photorhabdus laumondii and Pseudomonas aeruginosa, respectively, were produced in perdeuterated forms and crystallized with a ligand. A unique part of the thesis was the in vivo production of a perdeuterated monosaccharide, L-fucose, using genetically modified strains of E. coli bacteria designed by Dr. Eric Samain at CERMAV institute in Grenoble. Perdeuterated fucose has been successfully produced, purified and biophysically characterized. It was used as a ligand for crystallization trials of both PLL and LecB lectins.Three neutron structures have been solved in this thesis. Two structures of PLL lectin from P. laumondii both in apo and ligand-bound form and one structure of LecB lectin from P. aeruginosa in the complex with perdeuterated fucose.The results obtained in this thesis yielded one published publication, one submitted and one in preparation, which are all part of this manuscript
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
Neolectins : synthetic lectins with controlled valency and specificity for cell biology and biotechnology
No full textLa capacité des lectines à reconnaître spécifiquement des glycoconjugués à la surface de cellules en font des outils de diagnostic biomédical pour les pathologies associées à des changements de glycosylation (inflammation, du cancer ...). De par leur interaction avec les glycosphingolipides, ces protéines peuvent aussi être utilisées pour étudier le trafic membranaire. Toutefois, un nombre réduit de lectines sont actuellement disponibles, limitant leur utilisation dans les biotechnologies et la recherche. Le but de ma thèse est d'une part de concevoir des néo-lectines de valence et topologie contrôlées pour comprendre l'effet de la multivalence sur le mécanisme d'endocytose, et d'autre part de concevoir des lectines de spécificité modulable afin de les utiliser dans la reconnaissance spécifique des cellules tumorales.RSL est une lectine à fucose de la bactérie Ralstonia solanacearum qui a une structure en β-propeller formée par l'association de trois monomères présentant deux sites de liaison très similaires. Cette protéine trimérique et hexavalente a été choisie comme structure de base pour la conception de néolectines. Des RSLs trivalentes ont été produites par mutation d'un acide aminé essentiel pour la stabilisation du fucose. Leur caractérisation a démontré qu'ils avaient perdu la capacité d'invaginer la membrane plasmique. Une protéine de même structure que RSL mais monomérique a été ingénierée, puis une librairie de plus de 13 mutants de valence présentant différentes topologies a été créée. L'analyse de tous les mutants a permis de démontrer que la formation de tubules dans les membranes dépend plus de la distance entre les sites que du nombre de sites.Nous avons ensuite mis au point un protocole de bio-informatique afin de prédire l'orientation et la conformation d'oligosaccharides fucosylés dans les sites de fixation de plusieurs lectines à fucose. Les affinités relatives ont pu être calculées avec une bonne corrélation avec les valeurs expérimentales. La modélisation et la structure cristallographique des complexes entre RSL et les oligosaccharides Lewis X et Sialyl Lewis X indiquent un changement conformationnel du glycanne très inhabituel lors de l'interaction, donnant ainsi des pistes pour la conception de mutants de plus haute spécificité.The ability of lectins to specifically recognize glycoconjugates on cell surface makes them excellent biomedical diagnostics tools for diseases associated with glycosylation changes (e.g inflammation, cancer, etc.). Furthermore, because of their interaction with glycosphingolipids, lectins may also be used to study membrane trafficking. However, only small number of lectins are currently available, limiting their use in biotechnology and research. The aim of my thesis was first to develop neolectins with controlled valency and topology to understand the effect of multivalency on the endocytosis mechanism, and second to design lectins with tuned specificity for the recognition of tumor cells.RSL is a fucose binding lectin from the bacterium Ralstonia solanacearum which has a β-propeller structure that is formed by the association of three monomers each having two very similar binding sites. This trimeric and hexavalent protein was chosen as the scaffold structure for the design of neolectins. Trivalent RSLs were created by mutating an amino acid with essential role in fucose binding. Characterization showed that these mutants lost the ability to invaginate the plasma membrane. In addition, monomeric RSL was engineered and a library of more than 13 mutants, with different topologies and valencies, was created. Analysis of these mutants showed that the formation of tubules in the membrane depends mostly on the distance between the sites rather than on the number of sites.Then we developed a bioinformatic protocol to predict the orientation and conformation of fucosylated oligosaccharides in the binding sites of several fucose binding lectins. The relative affinities could be calculated with a good correlation to experimental values. Both the model and the crystal structures of RSL complexed with sialyl Lewis X and Lewis X oligosaccharides indicate a very unusual conformational change of the glycan during the interaction. These studies pave the way for the design of mutants with higher specificity
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
