1,721,131 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
Study of the impact of host genetics and gut microbiota composition on Salmonella Enteritidis carriage in mice and chickens
No full textSalmonella enterica Enteritidis (SE) est l’une des principales causes d’intoxication alimentaire humaine, par le biais de la consommation de produits aviaires (viande ou œufs) contaminés. Cette bactérie est portée de manière asymptomatique par la poule, mais peut infecter et rendre malade les consommateurs de ces produits. La sélection génétique et la modulation du microbiote intestinal sont deux moyens prometteurs de diminuer son portage chez la poule et sa propagation en élevage. Les objectifs de cette thèse sont d’identifier les principaux facteurs génétiques et microbiens contrôlant le portage individuel des salmonelles dans deux modèles expérimentaux. Le modèle “poulet” a été utilisé pour l’étude de l’impact du fonds génétique sur la résistance et le microbiote caecal de jeunes individus après une infection par SE. Des analyses de la composition du microbiote et de l’expression des gènes dans les tonsilles caecales ont été menées et ont permis d’identifier des bactéries intestinales (ex. Christensenellaceae), des gènes différentiellement exprimés (ex. Fut2) et des voies de signalisation potentielles (ex. voie des acides gras à chaîne courte) associés avec la réponse à l’infection. Un impact significatif de la lignée sur la composition du microbiote a également été identifié. Le modèle “souris” a été utilisé pour l’identification de régions génomiques de l’hôte contrôlant le portage chronique de SE. Deux populations génétiques de référence, les lignées du Collaborative Cross (CC) et les souris du Diversity Outbred (DO), ont permis d’identifier de nouveaux QTls (Ses11 à Ses17) et des gènes candidats tels que Lingo2 ou Btnl4 associés à la réponse à l’infection par SE. Chez les CC, nous avons également montré une large diversité des charges bactériennes dans le foie et la rate permettant d’identifier des lignées présentant des phénotypes extrêmes à SE, sensibles (ex. CC009/Unc) ou résistantes (ex. CC024/GeniUnc), et pouvant servir de nouveaux modèles expérimentaux. Ce projet a donc permis d'identifier de nouveaux mécanismes associés à la réponse à une infection par SE, grâce à l’exploitation de deux modèles expérimentaux complémentaires.Salmonella enterica Enteritidis (SE) is one of the major human food poisoning causes through the consumption of contaminated poultry products (meat and eggs). This bacterium is carried asymptomatically by chickens, but is able to infect humans and cause diseases. Genetic selection and intestinal microbiota modulation are two promising ways to reduce its carriage in chickens and its spread in poultry farms. The objectives of this thesis are to identify the main genetic and microbial factors controlling individual Salmonella carriage in two experimental models. The "chicken" model was used to study the impact of the genetic background on the resistance and the microbiota composition of young individuals post SE infection. Analyses of caecal microbiota composition and gene expression in caecal tonsils were conducted and led to the identification of intestinal bacteria (e.g. Christensenellaceae), differentially expressed genes (e.g. Fut2) and signalling pathways (e.g. short-chain fatty acid pathway) associated with the response to the infection. A significant impact of the line on microbiota composition was also identified. The "mouse" model was used to identify host genomic regions controlling chronic SE carriage. Two genetic reference populations, the Collaborative Cross (CC) strains and the Diversity Outbred (DO) mice, allowed the identification of new QTls (Ses11 to Ses17) and candidate genes such as Lingo2 or Btnl4 associated with the response to SE infection. In CC strains, we showed a high diversity of bacterial loads in liver and spleen, allowing the identification of strains with extreme phenotypes to SE, either susceptible (e.g. CC009/Unc) or resistant (e.g. CC024/GeniUnc), that could be used as new experimental models. This project has therefore allowed the identification of new mechanisms associated with the response to SE infection thanks to the use of two complementary experimental models
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
Improving gut health by modulating the digestive microbiota of chickens? How metagenomics can help.
No full textDispelling 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
Studying the digestive microbiota in chicken - Towards quantitative metagenomics
No full textNational audienc
Organisation génomique globale des facteurs de résistance à la tavelure (Venturia inaequalis), à l'oïdium (Podosphaera leucotricha) et au feu bactérien (Erwinia amylovora) chez le pommier (Malus Xdomestica)
No full text*INRA, Centre d'Angers, UMR GenHort Diffusion du document : INRA, Centre d'Angers, UMR GenHort Diplôme : Dr. d'Universit
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