1,721,336 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
Cluster spin glass phase and charge stripe fluctuations in the high TC superconductor La2-xSrxCuO4
No full textRelaxational lattice dynamics in La2-xSrxCuO4 and possible connection with the stripes in cuprate superconductors
No full textTunneling-driven tilt modes of the O octahedra in La2-xSrxCuO4: strong dependence on doping
No full textAnelastic relaxation from hydrogen and other defects in La-doped BaTiO3
No full textWe present anelastic spectroscopy measurements between 2 and 500 K in Ba1-xLaxTiO3 (0.10 <= x <= 0.20). The phase transitions of pure BaTiO3 are shifted to lower temperature by increasing the La doping and are completely suppressed starting from x = 0.15. The samples are expected to contain H impurities since sintering was performed in flowing H-2 to ensure electronic rather than cation vacancy compensation, and indeed at least three relaxation processes of the complex anelastic spectrum are strongly influenced by annealing the samples in CO or H-2 at 1450 K. A thermally activated anelastic peak around 250 K (f similar to 2 kHz) is ascribable to H hopping between different O atoms, while a possible indication of fast reorientation around a same O atom comes from a broad peak around 100 K. At least other three relaxation processes are present between 30 and 150 K, but the present data do not allow their nature to be ascertained; possible mechanisms involve polarons and hopping of Ti and possibly 12 among off-centre positions. (C) 2009 Elsevier B.V. All rights reserved
Acoustic measurement of the low-energy excitations in Nd2-xCexCuO4+d
No full textThe complex dynamic Young’s modulus of ceramic Nd22xCexCuO4 with x 1⁄4 0; 0.05 and 0.20 has been measured from 1.5 to 100 K at frequencies of 1–10 kHz. In the undoped sample the modulus starts decreasing below ,20 K, instead of approaching a constant value as in a normal solid. The modulus minimum has been interpreted in terms of paraelastic contribution from the
relaxation of the Nd3þ 4f electrons between the levels of the ground state doublet, which is split by the interaction with the antiferromagnetically ordered Cu sublattice. The value of the splitting is found to be 0.34 meV, in excellent agreement with inelastic neutron scattering, infrared and specific heat experiments. With doping, the anomaly shifts to lower temperature and decreases in amplitude, consistently with a reduction of the local field from the Cu sublattic
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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