1,720,960 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Ultrathin GaAs layers embedded in AlAs: a perspective for intense short wavelength emission
No full textType-II GaAs/AlAs quantum-well samples grown by low-pressure metal-organic vapour-phase epitaxy consisting of 50 periods of either 2 monolayers (ML), 4 ML, 5 ML, 6 ML, or 7 ML GaAs embedded in 28 ML AlAs were under investigation. Even at room temperature dominant type-I luminescence has been observed. The peak wavelength of this emission ranges from 620 to 440 nm and is determined by the GaAs layer thickness. A comparison of the measured transition energies with model calculations applying an effective mass approach and an empirical tight-binding Green's function scheme confirmed this strong dependence. To our knowledge this is the first report on intense yellow, green, and blue luminescence from GaAs. 1998 Published by Elsevier Science B.V. All rights reserved.LOEQUniv Leipzig, Fac Phys, D-04103 Leipzig, Germany. Univ Leipzig, Fac Chem, D-04103 Leipzig, Germany. Swiss Fed Inst Technol, Dept Phys, PH Ecublens, CH-1015 Lausanne, Switzerland. Pietag, F, Univ Leipzig, Fac Phys, Linnestr 3-5, D-04103 Leipzig, Germany.ISI Document Delivery No.: 118XVCited Reference Count: 6Cited References:DIVENTRA M, 1997, PHYS REV B, V55, P13148MADER KA, 1992, P INT M OPT EXC CONF, P341MADER KA, 1992, THESIS SWISS FEDERALMASCHKE K, 1991, PHYS REV LETT, V67, P2646MEYNADIER MH, 1988, PHYS REV LETT, V60, P1338MOORE KJ, 1989, SPECTROSCOPY SEMICON, P29
Minimum of oscillator strength of excitons in ultra-narrow GaAs/AlGaAs quantum wells: theory and experiment
No full textA theoretical and experimental study of the exciton in ultra-narrow quantum wells (QWs) is performed. A crossover from strong (separate localization of electron and hole levels) to weak confinement (with localization of excitonic center of mass) is predicted to occur for decreasing thickness, and is characterized by a minimum of the oscillator strength per unit area. Cathodoluminescence measurements performed on a series of GaAs/Al0.35Ga0.65As QWs with thicknesses from one to eight monolayers show a minimum of the oscillator strength, in agreement with theory, and indicate that the crossover from strong to weak confinement occurs at a thickness of about three monolayers for this composition
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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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