1,721,014 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
Nanocomposite, PEO-LiBOB polymer electrolytes for low temperature, lithium rechargeable batteries
No full textSynthesis of Mn spinels from different polymorphs of MnO2
No full textFour polymorphs of MnO2, i.e., alpha, beta, epsilon and ramsdellite, have been lithiated with Lil solutions to give LixMnO2 (0.4 <x < 0.7), Heating of these phases always results in spinel formation. beta- and epsilon-MnO2 are more easily converted into spinels, whereas the larger tunnels of alpha- and ramsdellite-MnO2 allow limitation of the LI-Mn repulsion causing the structural change. The formation of such by-products as Mn2O3 and Li2Mn3 has been demonstrated by X-ray and thermogravimetric and differential thermal analyses. Solid-state reactions of these polymorphs (with LiOH) also give rise to Mn2O3-contaminated spinels, in spite of the stoichiometric ratios. The electrochemical characteristics, as determined mainly by potential step voltammetry in the 4 V range, are similar to those of conventionally prepared spinels but the presence of by-products limits the available capacity
Direct synthesis of carboxylated polyurethanes
No full textThe first direct synthesis of a carboxylated polyurethane is described. The polyurethane, of the segmented type, was obtained by reaction of 4,4′-diphenylmethane diisocyanate with poly(propylene oxide) and the tributylammonium salt of dihydroxymethylpropionic acid. The polymer was characterized by viscometry, DSC, i.r. and NMR spectroscopy. The reactivity of the free carboxylic group in the polymer was evaluated for esterification and amidatio
Determintion of caffeic acid in wine at poly(3,4-ethylenedioxy)thiophene platinum modified electrode.
No full textSerotonin (5-HT) is an important neurotransmitter that plays important biological roles in various areas of the body. 5-HT is known to influence key neurological traits, such as anxiety [1], but also plays a key role in driving gastrointestinal motility and platelet aggregation.
Serotonin (5-HT) is a key neurotransmitter that is found in the brain, blood and gastrointestinal tract. Due to the interest in measuring this important biogenic amine in these various environments, measurements have been conducted without understanding the influence of the matrix on the stability of recordings
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