1,721,021 research outputs found
Iridoid and phenylpropanoid glucosides from Tecoma capensis
No full textLeaves of Tecoma capensis contain, together with tecomoside, large quantities of it's benzoic and cinnamic esters. A novel glucoside was isolated and, by spectroscopic and chemical data, characterized as 7-O-(p-methoxy) benzoyl tecomoside. Flowers of T. capensis contain only tecomoside, together with two phenylethanoid-derived glucosides, cornoside and it's rearranged aglycone, halleridone, and rengioside B. (C) 1997 Elsevier Science Ltd
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
Biophenolic profile in olives by nuclear magnetic resonance
No full textThe molecular composition of biophenols in olive fruit was investigated in order to experiment with novel procedures for the determination of these microcomponents in fresh and processed table olives. The presence of biophenols in table olives, with recognized antioxidant activity, can be strictly linked to the texture and the organoleptic characteristics of the food product, giving a functional value to this Mediterranean food. Olives from Spain ("Hojiblanca" cv.), Portugal ("Douro" cv.), Greece ("Conservolia" and "Thasos"cv.) and Italy ("Taggiasca" and "Cassanese" cv.) were examined, because the experimental data, checked by high-performance liquid chromatography (HPLC), show molecular composition differences in the tested samples related to the geographic area of analyzed olive fruit cultivars [Bianco, A., & Uccella, N. (2000). Biophenolic components of olives. Food Research International, 33, 475-485]. Three different protocols were utilized: the first one allows the determination of the biophenolic content present as free and esterified compounds; the second affords the total biophenolic content; the third indicates the biophenols present as glycosides. The biophenolic content, which was previously determined by classic HPLC methods (Bianco & Uccella, 2000), was checked by a simple]H-NMR experiment. The comparison between the data obtained from H-1-NMR with those measured by HPLC, indicates a good agreement and suggests the possibility of employing H-1-NMR for the rapid determination of biophenolic content in olives and also in other foods. (C) 2001 Elsevier Science Ltd. All rights reserved
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
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