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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
Metabolism of flavan-3-ols by the human gut microbiota : unraveling of bacterial species and genes involved
No full textLes flavan-3-ols font partie des polyphénols les plus consommés par l’Homme et sont présents sous la forme de monomères et d’oligomères tels que les procyanidines. La majorité des flavan-3-ols transite vers le côlon où réside le microbiote intestinal. Alors que les voies métaboliques de dégradation des flavan-3-ols par le microbiote sont relativement bien décrites, les microorganismes et les gènes microbiens impliqués dans ces voies sont très peu connus. L’objectif de la thèse était donc d’identifier les microorganismes et les gènes impliqués dans la dégradation des flavan-3-ols et en particulier des procyanidines. A partir de selles humaines de trois individus sains, des approches de culturomique combinées à un criblage de l’activité métabolique des isolats bactériens par HPLC-DAD ont permis d’obtenir quatre souches de l’espèce Eggerthella lenta et une souche de l’espèce Flavonifractor plautii capables de dégrader la (+) catéchine et la (-) épicatéchine. L’activité de ces souches a ensuite été testée sur les procyanidines de type B (DP2 à 4) et A (DP2) et les métabolites générés ont été caractérisés par LC-ESI-MS/MS. Nous avons ainsi montré pour la première fois que E. lenta est capable de dégrader les procyanidines. La réaction catalysée par E. lenta, validée sur les dimères, correspond à l’ouverture du cycle C de l’unité terminale. Par une approche transcriptomique (RNAseq) réalisée chez E. lenta, couplée à l’expression hétérologue des gènes d’intérêt chez Escherichia coli, nous avons mis en évidence deux gènes (fmber1, fmber2) codant deux benzyl ether reductases impliquées dans l’ouverture du cycle C des monomères et un opéron de deux gènes (pber) catalysant cette réaction sur les dimères de procyanidines de type B. Enfin, deux opérons de trois gènes (cadh, ecadh) codant deux complexes enzymatiques impliqués dans la déshydroxylation du cycle B de la (+) catéchine et de la (-) épicatéchine ont aussi été identifiés. En conclusion, les espèces E. lenta et F. plautii, ainsi que les gènes identifiés dans cette étude, constitueront à l’avenir de bons marqueurs du métabolisme microbien des flavan-3-ols chez l’Homme. Ceci permettra à terme de mieux appréhender les effets de la consommation des flavan-3-ols chez les individus en bonne santé ou à risque de maladies chroniques.Flavan-3-ols are among the most consumed polyphenols by humans and are present as monomers and oligomers such as procyanidins. The majority of flavan-3-ols reach the colon where the intestinal microbiota resides. While the metabolic pathways for the degradation of flavan-3-ols by the microbiota are relatively well described, only a few microorganisms and microbial genes involved in these pathways are known. The objective of the thesis was therefore to identify the microorganisms and genes involved in the degradation of flavan-3-ols and in particular procyanidins. From human stools of three healthy individuals, culturomic approaches combined with screening for the metabolic activity of bacterial isolates by HPLC-DAD allowed us to obtain four strains of the species Eggerthella lenta and one strain of the species Flavonifractor plautii degrading (+)-catechin and (-)-epicatechin. The activity of these strains was then tested on B-type (DP2 to 4) and A-type (DP2) procyanidins and the metabolites generated were characterized by LC-ESI-MS / MS. We have thus shown for the first time that E. lenta degrades procyanidins. The reaction catalyzed by E. lenta on dimers (B-type and A type), corresponds to the opening of the C-ring of the terminal unit. By a transcriptomic approach (RNAseq) carried out in E. lenta, coupled with the heterologous expression of the genes of interest in Escherichia coli, we have discovered two genes (fmber1, fmber2) encoding two benzyl ether reductases involved in the opening of the C ring of the monomers and an operon of two genes (pber) catalyzing this reaction on the dimers of type-B procyanidins. Finally, two operons of three genes (cadh, ecadh) encoding two enzymatic complexes involved in the dehydroxylation of the B-ring of (+)-catechin and (-)-epicatechin have also been identified. In conclusion, the species E. lenta and F. plautii, as well as the genes identified in this study, will constitute good markers of the microbial metabolism of flavan-3-ols in humans in the future. This will ultimately allow a better understanding of the effects of the consumption of flavan-3-ols in individuals in good health or at risk of chronic diseases
Métabolisme des flavan-3-ols par le microbiote intestinal humain : mise en évidence d’espèces bactériennes et de gènes impliqués dans la fonction
No full textFlavan-3-ols are among the most consumed polyphenols by humans and are present as monomers and oligomers such as procyanidins. The majority of flavan-3-ols reach the colon where the intestinal microbiota resides. While the metabolic pathways for the degradation of flavan-3-ols by the microbiota are relatively well described, only a few microorganisms and microbial genes involved in these pathways are known. The objective of the thesis was therefore to identify the microorganisms and genes involved in the degradation of flavan-3-ols and in particular procyanidins. From human stools of three healthy individuals, culturomic approaches combined with screening for the metabolic activity of bacterial isolates by HPLC-DAD allowed us to obtain four strains of the species Eggerthella lenta and one strain of the species Flavonifractor plautii degrading (+)-catechin and (-)-epicatechin. The activity of these strains was then tested on B-type (DP2 to 4) and A-type (DP2) procyanidins and the metabolites generated were characterized by LC-ESI-MS / MS. We have thus shown for the first time that E. lenta degrades procyanidins. The reaction catalyzed by E. lenta on dimers (B-type and A type), corresponds to the opening of the C-ring of the terminal unit. By a transcriptomic approach (RNAseq) carried out in E. lenta, coupled with the heterologous expression of the genes of interest in Escherichia coli, we have discovered two genes (fmber1, fmber2) encoding two benzyl ether reductases involved in the opening of the C ring of the monomers and an operon of two genes (pber) catalyzing this reaction on the dimers of type-B procyanidins. Finally, two operons of three genes (cadh, ecadh) encoding two enzymatic complexes involved in the dehydroxylation of the B-ring of (+)-catechin and (-)-epicatechin have also been identified. In conclusion, the species E. lenta and F. plautii, as well as the genes identified in this study, will constitute good markers of the microbial metabolism of flavan-3-ols in humans in the future. This will ultimately allow a better understanding of the effects of the consumption of flavan-3-ols in individuals in good health or at risk of chronic diseases.Les flavan-3-ols font partie des polyphénols les plus consommés par l’Homme et sont présents sous la forme de monomères et d’oligomères tels que les procyanidines. La majorité des flavan-3-ols transite vers le côlon où réside le microbiote intestinal. Alors que les voies métaboliques de dégradation des flavan-3-ols par le microbiote sont relativement bien décrites, les microorganismes et les gènes microbiens impliqués dans ces voies sont très peu connus. L’objectif de la thèse était donc d’identifier les microorganismes et les gènes impliqués dans la dégradation des flavan-3-ols et en particulier des procyanidines. A partir de selles humaines de trois individus sains, des approches de culturomique combinées à un criblage de l’activité métabolique des isolats bactériens par HPLC-DAD ont permis d’obtenir quatre souches de l’espèce Eggerthella lenta et une souche de l’espèce Flavonifractor plautii capables de dégrader la (+) catéchine et la (-) épicatéchine. L’activité de ces souches a ensuite été testée sur les procyanidines de type B (DP2 à 4) et A (DP2) et les métabolites générés ont été caractérisés par LC-ESI-MS/MS. Nous avons ainsi montré pour la première fois que E. lenta est capable de dégrader les procyanidines. La réaction catalysée par E. lenta, validée sur les dimères, correspond à l’ouverture du cycle C de l’unité terminale. Par une approche transcriptomique (RNAseq) réalisée chez E. lenta, couplée à l’expression hétérologue des gènes d’intérêt chez Escherichia coli, nous avons mis en évidence deux gènes (fmber1, fmber2) codant deux benzyl ether reductases impliquées dans l’ouverture du cycle C des monomères et un opéron de deux gènes (pber) catalysant cette réaction sur les dimères de procyanidines de type B. Enfin, deux opérons de trois gènes (cadh, ecadh) codant deux complexes enzymatiques impliqués dans la déshydroxylation du cycle B de la (+) catéchine et de la (-) épicatéchine ont aussi été identifiés. En conclusion, les espèces E. lenta et F. plautii, ainsi que les gènes identifiés dans cette étude, constitueront à l’avenir de bons marqueurs du métabolisme microbien des flavan-3-ols chez l’Homme. Ceci permettra à terme de mieux appréhender les effets de la consommation des flavan-3-ols chez les individus en bonne santé ou à risque de maladies chroniques
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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