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Secondary metabolism related to the biosynthesis of aflatoxins and their congeners "in vitro"
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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
Effect of antioxidants and free radical scavengers on aflatoxin production "in vivo".
No full textWe demonstrated previously that some antioxidants butylated hydroxy toluene (BHT), butylated hydroxyanisole (BHA), cysteamine and sodium thiosulfate (THIO) – were capable of inhibiting, to different extents and depending upon their concentration, the output of aflatoxins induced by lipoperoxides in cultures of Aspergillus parasiticus. However, other antioxidants (vitamin E, vitamjn C, reduced glutathione) increased significantly the production of mycotoxins. Following these findings we tested the effect of different concentrations (0 01-0 1% w/v) of the above compounds on wheat, maize and sunflower seeds properly moistened and inoculated with 106 conidia of a toxigenic strain of A. parasiticus (NRRL 2999). Uniform distribution of the antioxidants into the seeds was achieved by suspending them in 0 1% alkylamide betaine (an ampholitic detergent). Analysis of aflatoxins was carried out by HPLC on RP18 column. Hexosamine measurements were performed by GLC for the assesment of fungal growth in infected seeds. After 30 days of incubation, fungal growth and aflatoxin levels were much higher in sunflower than in maize or wheat seeds. Among the antioxidants tested, only BHA and BHT, mainly in association with 0.1% THIO, significantly reduced aflatoxin levels (p<0.05). The inhibitory effect was more evident in wheat and maize than in sunflower seeds and was due to three basic reasons: a) more marked reduction of fungal growth in starchy seeds; b) higher content of superficial lipids in the hull of sunflower seeds; c) higher content of phenoloxidases in the hull of sunflower seeds. the two last factors are capable of lowering the concentrations of BHA and BH
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
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