1,720,959 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
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
L'épigénétique comme modulateur de l'expression de hTERT dans les lymphomes T cutanés
No full textCutaneous T-lymphomas (CTCL) are telomerase-positive tumors expressing hTERT, in which neither amplification, nor rearrangement, nor promoter hotspot mutations can explain the re-expression of the gene. As the hTERT promoter is rich in CpG, we investigated the contribution of epigenetic mechanisms in its re-expression, since no studies to date have been reported in CTCL. We analyzed the methylation status of the hTERT promoter in cell lines, patients’ cells and in cells from healthy donors. We also studied the presence, on the hTERT promoter, of histones H3K27ac and H3K27me3. Methylation analyzes in CTCL cells revealed a characteristic methylation profile specific to tumor cells, encompassing a distal hypermethylated region from -650 bp to -150 bp and a proximal hypomethylated region from -150 bp to +150 bp, relatively to the TSS. This dual methylation profile on hTERT promoter is identical to the profile seen in other types of tumors. The hypermethylated distal region identified in CTCL tumor cells corresponds to the region recently named “TERT hypermethylated oncogenic region” (THOR) and which is reported to be associated with telomerase reactivation in several tumors, but so far not reported in lymphomas. We evaluated the effect on THOR of two histone deacetylases inhibitors (HDACi), romidepsin and vorinostat, both approved for the treatment of CTCL as well as a DNA methyltransferase inhibitor (DNMTi) 5- azacytidine, not approved for CTCL. Our results, obtained from a limited cohort, seem to suggest that 5-azacytidine does not cause a demethylation of the hypermethylated region on hTERT promoter, while this treatment is accompanied by a decrease in the expression of hTERT and, functionally with a decrease in the clonogenic capacities of tumor cells. Romidepsin and vorinostat can slightly modify the H3K27ac and H3K27me3 histone marks present on hTERT promoter. In conclusion, the results obtained in CTCL cells compared with those of healthy cells confirm that hTERT promoter methylation is specific to CTCL cells, making this methylation a biomarker of tumor cells. Furthermore, they reveal that the methylation of hTERT promoter is relatively stable even under the pressure of epigenetic therapies, suggesting that the regulation of hTERT by these therapies can happen indirectly.Les lymphomes T-cutanés (CTCL) sont des tumeurs télomérase-positives exprimant hTERT, dans lesquelles ni l'amplification, ni les réarrangements, ni les mutations hotspots du promoteur peuvent expliquer la ré-expression du gène. Comme le promoteur de hTERT est riche en CpG, nous avons étudié la contribution des mécanismes épigénétiques dans sa ré-expression, puisqu’aucune étude à ce jour n’a été rapporté dans les CTCL. Nous avons analysé le statut de méthylation du promoteur de hTERT dans des lignées cellulaires, des cellules de patients ainsi que dans des cellules issues de donneurs sains. Nous avons également étudié la présence sur le promoteur de hTERT des histones H3K27ac et H3K27me3. Les analyses de méthylation spécifiques des cellules CTCL ont révélé un profil de méthylation caractéristique limité aux cellules tumorales, englobant une région distale hyperméthylée de -650 pb à -150 pb et une région proximale hypométhylée de -150 pb à + 150 pb, à partir du TSS. Ce double profil de méthylation observé sur le promoteur de hTERT est identique à celui observé dans d’autres types de tumeurs. La région distale hyperméthylée identifiée dans les cellules tumorales CTCL correspond à la région nommée récemment « région TERT oncogénique hyperméthylée » (THOR) et qui est rapportée associée à la réactivation de la télomérase dans les tumeurs, mais jusqu'à présent non rapportée dans les lymphomes. Nous avons évalué l'effet sur THOR de deux inhibiteurs d’histone désacétylases (HDACi), la romidepsine et le vorinostat, tous deux approuvés pour le traitement des CTCL ainsi que d'un inhibiteur de l'ADN méthyltransférase (DNMTi) 5-azacytidine, non approuvé pour les CTCL. Nos résultats obtenus à partir d’une cohorte limitée semblent suggérer, que la 5-azacytidine ne provoque pas la déméthylation de la région hyperméthylée du promoteur de hTERT alors que ce traitement s’accompagne d’une diminution de l’expression de hTERT et, fonctionnellement d’une baisse des capacités clonogènes des cellules. La romidepsine et le vorinostat modifient peu les marques d'histones H3K27ac et H3K27me3 présentes au niveau du promoteur hTERT. En conclusion, les résultats obtenus dans les cellules CTCL comparées à ceux de cellules saines confirment que la méthylation du promoteur de hTERT dans les cellules tumorales est particulière et spécifique à ces cellules, faisant de cette méthylation un biomarqueur de la cellule tumorale. De plus, ils révèlent que la méthylation du promoteur hTERT est relativement stable même sous la pression de thérapies épigénétiques, suggérant que la régulation de hTERT par ces thérapies s’opère en priorité de manière indirecte
Epigenetic modulation of hTERT expression in cutaneous T-cell lymphomas
No full textLes lymphomes T-cutanés (CTCL) sont des tumeurs télomérase-positives exprimant hTERT, dans lesquelles ni l'amplification, ni les réarrangements, ni les mutations hotspots du promoteur peuvent expliquer la ré-expression du gène. Comme le promoteur de hTERT est riche en CpG, nous avons étudié la contribution des mécanismes épigénétiques dans sa ré-expression, puisqu’aucune étude à ce jour n’a été rapporté dans les CTCL. Nous avons analysé le statut de méthylation du promoteur de hTERT dans des lignées cellulaires, des cellules de patients ainsi que dans des cellules issues de donneurs sains. Nous avons également étudié la présence sur le promoteur de hTERT des histones H3K27ac et H3K27me3. Les analyses de méthylation spécifiques des cellules CTCL ont révélé un profil de méthylation caractéristique limité aux cellules tumorales, englobant une région distale hyperméthylée de -650 pb à -150 pb et une région proximale hypométhylée de -150 pb à + 150 pb, à partir du TSS. Ce double profil de méthylation observé sur le promoteur de hTERT est identique à celui observé dans d’autres types de tumeurs. La région distale hyperméthylée identifiée dans les cellules tumorales CTCL correspond à la région nommée récemment « région TERT oncogénique hyperméthylée » (THOR) et qui est rapportée associée à la réactivation de la télomérase dans les tumeurs, mais jusqu'à présent non rapportée dans les lymphomes. Nous avons évalué l'effet sur THOR de deux inhibiteurs d’histone désacétylases (HDACi), la romidepsine et le vorinostat, tous deux approuvés pour le traitement des CTCL ainsi que d'un inhibiteur de l'ADN méthyltransférase (DNMTi) 5-azacytidine, non approuvé pour les CTCL. Nos résultats obtenus à partir d’une cohorte limitée semblent suggérer, que la 5-azacytidine ne provoque pas la déméthylation de la région hyperméthylée du promoteur de hTERT alors que ce traitement s’accompagne d’une diminution de l’expression de hTERT et, fonctionnellement d’une baisse des capacités clonogènes des cellules. La romidepsine et le vorinostat modifient peu les marques d'histones H3K27ac et H3K27me3 présentes au niveau du promoteur hTERT. En conclusion, les résultats obtenus dans les cellules CTCL comparées à ceux de cellules saines confirment que la méthylation du promoteur de hTERT dans les cellules tumorales est particulière et spécifique à ces cellules, faisant de cette méthylation un biomarqueur de la cellule tumorale. De plus, ils révèlent que la méthylation du promoteur hTERT est relativement stable même sous la pression de thérapies épigénétiques, suggérant que la régulation de hTERT par ces thérapies s’opère en priorité de manière indirecte.Cutaneous T-lymphomas (CTCL) are telomerase-positive tumors expressing hTERT, in which neither amplification, nor rearrangement, nor promoter hotspot mutations can explain the re-expression of the gene. As the hTERT promoter is rich in CpG, we investigated the contribution of epigenetic mechanisms in its re-expression, since no studies to date have been reported in CTCL. We analyzed the methylation status of the hTERT promoter in cell lines, patients’ cells and in cells from healthy donors. We also studied the presence, on the hTERT promoter, of histones H3K27ac and H3K27me3. Methylation analyzes in CTCL cells revealed a characteristic methylation profile specific to tumor cells, encompassing a distal hypermethylated region from -650 bp to -150 bp and a proximal hypomethylated region from -150 bp to +150 bp, relatively to the TSS. This dual methylation profile on hTERT promoter is identical to the profile seen in other types of tumors. The hypermethylated distal region identified in CTCL tumor cells corresponds to the region recently named “TERT hypermethylated oncogenic region” (THOR) and which is reported to be associated with telomerase reactivation in several tumors, but so far not reported in lymphomas. We evaluated the effect on THOR of two histone deacetylases inhibitors (HDACi), romidepsin and vorinostat, both approved for the treatment of CTCL as well as a DNA methyltransferase inhibitor (DNMTi) 5- azacytidine, not approved for CTCL. Our results, obtained from a limited cohort, seem to suggest that 5-azacytidine does not cause a demethylation of the hypermethylated region on hTERT promoter, while this treatment is accompanied by a decrease in the expression of hTERT and, functionally with a decrease in the clonogenic capacities of tumor cells. Romidepsin and vorinostat can slightly modify the H3K27ac and H3K27me3 histone marks present on hTERT promoter. In conclusion, the results obtained in CTCL cells compared with those of healthy cells confirm that hTERT promoter methylation is specific to CTCL cells, making this methylation a biomarker of tumor cells. Furthermore, they reveal that the methylation of hTERT promoter is relatively stable even under the pressure of epigenetic therapies, suggesting that the regulation of hTERT by these therapies can happen indirectly
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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