1,720,963 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
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
Two-Step Biocatalytic Synthesis of (1S)-Nor(pseudo)ephedrine Catalyzed by Immobilized Enzymes
No full textNor(pseudo)ephedrines [N(P)Es] are naturally occurring compounds showing sympathomimetic activity that have many applications especially in the chemical industry and in the pharmaceutical field. Recently a two-step biocatalytic cascade for the preparation of (1S)-N(P)E was designed, consisting of a benzoin-type condensation catalyzed by the (S)-selective acetoin:dichlorophenolindophenol oxidoreductase (Ao : DCPIP OR) followed by a transamination mediated by either a (S)- or (R)-selective amine transaminase (ATA). In this study, we successfully immobilized both Ao : DCPIP OR and two ATAs of opposite enantioselectivity and used them in the biosynthetic cascade to N(P)Es. Immobilization yield, activity recovery, and stability of the immobilized enzymes, both after use (enzyme recycling) and storage (shelf-life), were assessed. Ao : DCPIP OR immobilized on glyoxyl-agarose exhibited remarkable stability under storage conditions throughout the 30-days monitoring period. Moreover, it was successfully reused in the synthesis of (S)-phenylacetylcarbinol [(S)-PAC] yielding high conversion (>94 %) and enantiomeric excess (>99 %). The (R)-selective At-ATA from Aspergillus terreus, immobilized on Eupergit (R) C, demonstrated a slightly higher storage stability when compared to the (S)-selective Sbv333-ATA from Streptomyces sp. Bv333 immobilized on the same carrier. Remarkably, both enzymes were effectively reused for ten reaction cycles in the synthesis of N(P)Es, starting from the enzymatically synthesized (S)-PAC, achieving complete conversions and excellent diastereoselectivity (>99 %)
Discovery and Characterization of a Novel Thermostable β-Amino Acid Transaminase from a Meiothermus Strain Isolated in an Icelandic Hot Spring
Get PDFA Meiothermus strain capable of using β-phenylalanine for growth is isolated by culture enrichment of samples collected in hot environments and the genome is sequenced showing the presence of 22 putative transaminase (TA) sequences. On the basis of phylogenetic and sequence analysis, a TA termed Ms-TA2 is selected for further studies. The enzyme is successfully produced in Escherichia coli Rosetta(DE3) cells, with 70 mg of pure protein obtained from 1 L culture after purification by affinity chromatography. Ms-TA2 shows high activity toward (S)-β-phenylalanine and other (S)-β-amino acids, as well as a preference for α-ketoglutarate and aromatic aldehydes as amino acceptors. Moreover, Ms-TA2 is shown to be a thermostable enzyme by maintaining about 60% of the starting activity after 3 h incubation at 50 °C and showing a melting temperature of about 73 °C. Finally, a homology-based structural model of Ms-TA2 is built and key active site interactions for substrate and cofactor binding are analyzed
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
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