1,720,964 research outputs found
Analytic Methods of Bioactive Metabolites Produced by plants and Microorganisms
No full textA review. HPLC and/or HPTLC, mass spectrometric and immunochem. methods for the anal. of natural bioactive metabolites are described. In particular, methods developed for the anal. of metabolites from plants and microorganisms in complex mixts. represent an important tool to investigate the biosynthesis and the mode of action of these metabolites for their large scale prodn. and for their practical applications
Recent achievement in the bio-control of Orobanche infesting important crops in the Mediterranean basin
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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
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
3 New Toxic Pinolidoxins From Ascochyta-pinodes
No full textThree new pinolidoxins called epi-, dihydro-, and epoxy-pinolidoxin (2, 4, and 5, respectively)were isolated from Ascochyta pinodes grown on wheat, and theirs structures were determined using spectroscopic and chemical methods. They were characterized as 7-epi-, 5,6-dihydro-, and 5,6-epoxy-pinolidoxin, respectively. Assayed on pea and bean leaves, epipinolidoxin and dihydropinolidoxin caused necrotic lesions, whereas epoxypinolidoxin was inactive. Only epipinolidoxin and epoxypinolidoxin were active using the brine shrimp assay
Ascosonchine, the enol tautomer of 4-pyridylpyruvic acid with herbicidal activity produced by Ascochyta sonchi
No full textA new phytotoxic enol tautomer of 4-pyridylpyruvic acid, named ascosonchine, was isolated from the culture filtrate of Ascochyta sonchi. Such a leaf pathogen is a potential biocontrol agent of Sonchus arvensis, a perennial herbaceous weed occurring throughout the temperate regions of the world. Ascosonchine, characterized as (Z)-2-hydroxy-3-(4-pyridyl)-2-propenoic acid by spectroscopic methods, showed selective herbicidal properties, that are not assocd. with antibacterial, antifungal or zootoxic activities
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