1,721,185 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
Cloud-point curves of ethylene-(meth)acrylate copolymers in fluid ethene up to high pressures and temperatures - experimental study and PC-SAFT modeling
No full textCloud-point pressures of ethylene-(meth)acrylic acid ester copolymers in supercritical ethene have been measured to maximum pressures and temperatures of 3000 bar and 533 K, respectively. The copolymers under investigation were prepared in a continuously operated stirred tank reactor (CSTR), which ensures production of chemically homogeneous polymer. After isolation and purification of the copolymer, the phase behavior was mapped out in a discontinuously operated high-pressure cell. The influence of the type and of the content of (meth)acrylate units within the copolymer on cloud-point behavior in mixtures with ethene was systematically studied for ethylene-ethyl acrylate (poly(E-co-EA)), ethylene-propyl acrylate (poly(E-co-PA)), ethylene-methyl methacrylate (poly(E-co-MMA)), and ethylene-butyl methacrylate (poly(E-co-BMA)) copolymers mostly covering the entire comonomer composition range including the limiting homopolymer systems ethene-polyethylene and ethene-poly(meth)acrylate. The data is compared with previously measured cloud-point pressures for ethylene-methyl acrylate and ethylene-butyl acrylate copolymers in fluid ethene. Starting from the limiting ethene-polyethylene system, cloud-point pressures decrease upon increasing the content of polar comonomer segments. For poly(E-co-MA), poly(E-co-EA), poly(E-co-MMA), and poly(E-co-BMA) this tendency is reversed at higher (meth)acrylic acid ester contents where the cloud-point pressures increase again. No such minimum in cloud-point pressure as a function of comonomer content occurs with poly(E-co-PA) and poly(E-co-BA). The variation of cloud-point pressure with copolymer composition is assigned to effects resulting from (i) short-chain branches on the polymer backbone, (ii) intersegmental interactions of carbonyl groups being shielded to different extents by the various types of alkyl ester groups, and (iii) "entropy penalty" contributions associated with the introduction of the a-methyl groups in case of the methacrylates. The experimental cloud-point-pressure curves are satisfactorily modeled by the Perturbed-chain (PC)-statistical associating fluid theory (SAFT) equation of state. The entire set of pure-component parameters and the three binary interaction parameters are independent of temperature, pressure and polymer molecular weight. The parameters from PC-SAFT modeling allow for estimates of the cloud-point behavior of ethene-poly(E-co-(meth)acrylate) systems in wide ranges of pressure and temperature. (C) 2003 Elsevier B.V. All rights reserved
Phase equilibria in polydisperse and associating copolymer solutions: Poly (ethene-co-(meth)acrylic acid)-monomer mixtures
No full textPhase equilibria of copolymer-monomer mixtures have been modeled on the basis of experimental cloud-point pressure curves for poly(ethene-co-acrylic acid) and for poly(ethene-co-methacrylic acid). The monomer system was ethene. In case of poly(ethene-co-acrylic acid), in addition, ethene-acrylic acid mixtures were used as the solvent. The association term of the PC-SAFT equation of state has been extended to account for the polydispersity of the copolymer samples. For this purpose, two pseudo-components were introduced for each copolymer. The amount and the molecular weight of these components were related to the number and weight averages of the copolymer material, M-n and M-w, respectively. For the strongly hydrogen-bonded systems, the influence on cloud-point pressures of copolymer composition and of molecular weight distribution can be adequately described by PC-SAFT modeling with temperature-independent parameters. (c) 2006 Elsevier B.V. All rights reserved
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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