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Laboratory experiments on the physical properties of the seismogenic Triassic evaporites of Umbria-Marche and their relation to crustal scale data
No full textEvolution of mechanical properties under cyclic stress experiments: results and microstructures of Triassic Evaporites
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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
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
Evolution of the elastic moduli of seismogenic Triassic Evaporites subjected to cyclic stressing
No full textSeismic cycles lead to variations in rock physical properties. Quantifying these changes is of key importance in building reliable crustal deformation models. Here we report laboratory measurements of the uniaxial compressive strength (UCS), Young's modulus and Poisson's ratio, both static (Es, νs) and dynamic (Ed, νd) of the seismogenic Triassic Evaporites of the Northern Apennines. Triassic Evaporites are composed of dolostones, anhydrites and gypsum. Gypsum was the weakest lithology, with UCS values ranging from 10 to 26 MPa; anhydrite exhibited intermediate values from 52 to 144 MPa; and dolostones were the strongest with a maximum UCS of 228 MPa.
During uniaxial cyclic stressing experiments, we observed complex variations in Es and νs with: large increases are observed in the early cycles (stage 1), followed by essentially constant values (stage 2), before Es decreases and νs increases approaching failure (stage 3). Complementary microseismicity (acoustic emission, AE) data show no significant AE during stage 1, then the stress needed to induce AE remained essentially constant (stages 2 and 3). Integration of mechanical data with microstructural observations suggests a first stage dominated by compaction and strengthening, a second stage characterised by quasi-elastic behaviour associated with the development of randomly oriented microfractures, and a third stage of weakening due to the growth of macrofractures parallel to the direction of the load. Laboratory dynamic elastic moduli are, on average, in agreement with dynamic elastic moduli used in crustal modelling. However static values of Young's modulus are about 50% lower than dynamic ones, and static values of Poisson's ratio are about 40% higher with respect to dynamic values. These observations suggest that the frequency effect on the difference between laboratory and crustal scale dynamic moduli values is rather small and that static values of modulus are more appropriate for crustal deformation modelling than seismically derived values
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
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