1,721,031 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
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
Evolution of lactic acid bacteria as revealed by comparative genomics of carbohydrate metabolism
No full textLactic acid bacteria (LAB) are a functional group of bacteria crucial in human nutrition for their role in fermented food production and their presence in gastro-intestinal tract. Co-evolution and niche-adaptation of LAB have been extensively analysed in several phylogenomic studies, thanks to the availability of complete genome sequences.
The aim of this study was to analyze the evolution of LAB from a different viewpoint: the comparative analysis of the metabolic pathways related to carbohydrate metabolism.
The analysis was performed on 40 LAB genomes belonging to strains of Enterococcaceae, Lactobacillaceae, Leuconostocaceae and Streptococcaceae families. A reference phylogenetic tree was inferred from the concatenation of 42 ribosomal proteins; moreover 45 genes belonging to Embden-Meyerhof-Parnas pathway (or glycolysis, EMPP) and pentose phosphate pathway (PPP) were analyzed in terms of presence/absence, number of paralogs and their use as phylogenetic markers.
Phylogenetic analysis confirmed the paraphyly of Lactobacillaceae while the analysis of EMPP and PPP genes distribution revealed the occurrence of lineage-specific trends of gene loss/gain within the two metabolic pathways in LAB. In addition, the investigation of EMPP and PPP as structures resulting from different evolutionary processes provided new information concerning the genetic bases of heterofermentative/homofermentative metabolism.
Overall, our analyses offered a better comprehension of the molecular mechanisms and the evolutionary processes that have led to contemporary biochemical pathways in LAB representatives.
The same approach could then be applied to other metabolic pathways in order to set up directed evolution experiments to improve production of LAB peculiar components with health-promoting or probiotic effects
Evolution of lactic acid bacteria in the order Lactobacillales as depicted by analysis of glycolysis and pentose phosphate pathways
No full textLactic acid bacteria (LAB) represent a functional group of bacteria that are fundamental in human nutrition because of their prominent role in fermented food production and their presence as commensals in the gut. LAB co-evolution and niche-adaptation have been analyzed in several phylogenomic studies due to the availability of complete genome sequences. The aim of this study was to provide novel insights into LAB evolution through the comparative analysis of the metabolic pathways related to carbohydrate metabolism. The analysis was based on 42 LAB genome sequences of representative strains belonging to Enterococcaceae, Lactobacillaceae, Leuconostocaceae and Streptococcaceae. A reference phylogenetic tree was inferred from concatenation of 42 ribosomal proteins; then 42 genes belonging to the Embden-Meyerhof-Parnas (or glycolysis; EMPP) and pentose phosphate (PPP) pathways were analyzed in terms of their distribution and organization in the genomes. Phylogenetic analyses confirmed the paraphyly of the Lactobacillaceae family, while the distribution and organization of the EMPP and PPP genes revealed the occurrence of lineage-specific trends of gene loss/gain within the two metabolic pathways examined. In addition, the investigation of the two pathways as structures resulting from different evolutionary processes provided new information concerning the genetic bases of heterofermentative/homofermentative metabolism
Phylogenomics of lactic acid bacteria: an insight from carbohydrate metabolism.
No full textLactic acid bacteria (LAB) are a functional group of bacteria with a prominent role in the production of fermented food products and in human health as commensals in the gut. Due to their biological and industrial properties, LAB have been extensively investigated and a number of genome sequences have been obtained.
The aim of this study was to perform a comparative genomics of LAB and provide novel insights into their evolution through the analysis of the genetic background of carbohydrate metabolism.
The analysis was based on 40 LAB genome sequences of strains belonging to Enterococcaceae, Lactobacillaceae, Leuconostocaceae and Streptococcaceae representatives. A phylogenetic tree was inferred from the concatenation of 42 ribosomal proteins and used as a reference to map the distribution of 45 genes of glycolysis and pentose phosphate (PP) pathway. These genes were analysed as phylogenetic markers and also in terms of presence/absence and number of paralogs.
Main observations concerned the occurrence of lineage-specific trends of gene loss/acquisition, revealing the mosaicism of the two metabolic pathways in these bacteria. Moreover, the paraphyly of Lactobacillaceae family was confirmed and additional information was obtained on the genetic bases of heterofermentative/homofermentative metabolism.
In this study, a modus operandi for comparative genomics was also delineated, in which different genes are given different weight in the analysis, depending on their strain-, subspecies- and species-specific distribution. As the number of available genome sequences increases, the underrepresentation of some taxa and the omission to fully consider the taxonomic framework are predicted to be the most crucial factors in comparative genomics and evolutionary analyses
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