1,721,166 research outputs found
Porposal for a Tecnological Riqualification of an Energetic System Serving a University Campus.
No full textHydrogen diffusivity and electrical anisotropy of a peridotite mantle
No full textLong-period magnetotelluric (MT) data have indicated that electrical conductivity in the upper mantle is highly anisotropic. Rates and anisotropies for self-diffusion of hydrogen in single crystals of mantle minerals are related to electrical resistivity by the Nernst-Einstein relationship. Assuming that the dominant mechanism for electrical conduction in the mantle is hydrogen diffusion, the electrical anisotropy of a peridotite should be controlled by its mineral composition and by the lattice-preferred orientation (LPO) of its constitutive minerals. Macroscopic electrical anisotropies arising from diffusion of hydrogen in upper mantle rocks displaying strain-induced LPO of olivine, enstatite and diopside are calculated using resistor networks in which each resistor has a statistical probability of representing a mineral grain with a particular misorientation relative to the olivine [100] maximum density direction. The orientations of the grains are defined by angular distribution functions describing LPO (1) generated by viscoplastic self-consistent modelling at a range of shear strains and (2) measured in a naturally deformed peridotite. The naturally deformed peridotite displays a strong LPO, but the predicted mean electrical anisotropy factor is less than 3. Geophysical data indicate higher electrical anisotropies for the mantle. This suggests that grain boundary processes that are controlled by shape-preferred orientation of crystals and/or macroscopic heterogeneities further enhance the electrical anisotropy of the mantle. Ambiguities in the conduction mechanism highlight the need for direct laboratory measurements of ionic conductivities in mantle assemblages that can be compared with those calculated from the Nernst-Einstein equation
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
Dislocazione tardiva di un uncino peduncolare in paziente con pregresso intervento di scoliosi: rara causa di siringomielia. Atti del 56° Congresso della Società Italiana di Neurochirurgia, 2007. In collaborazione con
No full textTechnical end Economic Feasibility Study of a Cogeneration System Serving a Large University Site
No full textTumore fibroso solitario del sistema nervoso: descrizione di un caso a localizzazione intramidollare
No full textDispelling 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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