1,721,188 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
Characterization of defectiveness of oxygen transport membranes deposited by Low Pressure Plasma Spraying – Thin Film processes
No full textNeutron Diffraction study of feldspar glasses. Mixed alkali effect
No full textRadial distribution function analysis was made using neutron diffraction on several glasses along the NaA1Si308-KA1Si308 (albite-orthoclase) join as well as on a natural obsidian sample. Comparison of the interference functions in
reciprocaI space shows a non-linear increase of the width of the first sharp diffraction peak which indicates a decrease of the
medium-range order (MRO) with increasing K20 content. The observed changes in the MRO were correlated with the
non-linear variation of the bulk transition temperature, Tg, and might reflect a strong temperature dependence of the corresponding liquid structures
Compression mechanism in aluminosilicate melts: Raman and XANES spectroscopy of glasses quenched from pressures up to 10 Gpa
No full textRaman and XANES spectroscopy were carried out on a series of glasses of composition 44CaO–12Al2O3–44SiO2,
formed at pressures up to 10 GPa by isobaric quench from a temperature of 2200°C. The most significant changes in the Raman spectrum as a function of the synthesis pressure, or density, of the glass occur in the low-frequency region (300–700
cm-1), associated with T–O–T bending vibrations. With increasing density of the glass, the overall intensity at low frequencies decreases relative to the high-frequency portion of the spectrum. Relative intensities of bands within the low-frequency region of the Raman spectrum are also very sensitive to synthesis pressure, whereas there is little evidence that pressure influences Q-speciation as the high-frequency region of the spectrum remains virtually unchanged. With initial
compression (V/V0=1–0.96), the severe loss in intensity near 500 cm-1 indicates coordination of bridging oxygen atoms to an additional cation, which inhibits the vibrational motion that gives rise to this band normally observed for silicate
glasses formed at ambient pressure. At higher densities(V/V0<0.96), bands in the low-frequency region are shifted to higher frequencies, indicative of narrower T–O–T angles. No significant changes are observed in the Si and Ca K-edge XANES spectra with increasing densification of the glass. The Al K-edge spectra also show no significant changes among
the lower density glasses (V/V0=1–0.96), but reveal a feature near 1570 eV that dramatically increases in relative intensity
with increasing densification beyond V/V0=0.96. The observations from both Raman and XANES spectroscopy are
consistent with two different compression mechanisms operating in different pressure ranges. At lower pressures, the
spectroscopic data are characterized by features that we attribute to the presence of triclusters(OT3 units) in the quenched
melt. At higher pressures, T–O–T angle reduction and also an increase in the average coordination number of Al are likely to occur to further reduce the volume of the melt. The complex response of the structure of aluminosilicate melts to
compression suggests that their physical properties will also behave complexly as a function of pressure
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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