1,720,992 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
XANES studies of Fe in pumpellyite-group minerals
No full textA study of the absorption spectra in the Fe K near-edge region of four mineral samples of the pumpellyite-group with different total Fe content was performed. The Fe-rich samples from low-grade metamorphic rocks (Keweenawan basalts, Michigan; porphyrites from Torrente Bulla, Italy) essentially contain all structural Fe in the octahedrally coordinated trivalent state, in contrast to the commonly used crystal-chemistry rules for the computation of the pumpellyite chemical formula. The Fe in an iron-poor sample from high pressure environment (glaucophane-lawsonite bearing rock from Hicks Ranch, California) is shown to be 6-coordinated divalent iron, in agreement with previous structural studies on Al-rich pumpellyites
Palygorskite From Bolca, Italy - A Characterization By High-resolution Synchrotron-radiation Powder Diffraction and Computer Modeling
No full textA new find of the mineral palygorskite from Bolca, Vicenza, Italy is described. The mineral occurs in association with calcite and diaspore along the shear fractures and in the veins of secondary minerals in the Eocene marls of the Bolca quarry, a locality known for its well-preserved fossil specimens. Selected regions of the X-ray powder diffraction spectra (XRPD) were collected using X-ray synchrotron radiation and high-resolution parallel-beam geometry. The data are interpreted by comparison with the computer-simulated powder diffraction patterns relative to the proposed strcture models for palygorskite. Cell parameters and relative phase weight evaluation were obtained by model-constrained Rietveld refinement. The sample was also investigated by electron probe micro-analysis (EPMA), TGA and DTG analysis, and SEM imaging. The average material is a mixture containing about 60% orthorhombic palygorskite, 30 % monoclinic palygorskite, and less than 10 % calcite and diaspore impurities. The association of the two different varieties of palygorskite is in agreement with recent re-evaluation studies of the mineral from different localities, showing the ubiquitous presence of the two forms
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