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Magmatism and tectonics in the Easternmost sector of a transversal fault system in Central Andes: a contribution for Miocene geodynamical evolution of the Andean margin at 24S
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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
The Late Miocene Chivinar volcanic complex (24o14’S – 67o27’W, Central Andes): calcalkaline and intraplate magma sources at the intersection of the Calama-Olacapato-El Toro volcanic belt and the arc
No full textThe Miocene Chivinar volcanic complex is located in NW Argentina, at the intersection of the Calama-Olacapato-El Toro back-arc volcanic belt and the active arc (Fig. 1). Chivinar includes very different rocks: in a first phase of volcanic activity topaz-bearing rhyolitic lava domes emplaced, while, in a later phase, dacitic and andesitic lavas were erupted (Koukharsky et al., 1991; Orlandi et al., 2011; Gioncada et al., 2014). The topaz-bearing rhyolitic lavas have sanidine and oligoclase phenocrysts in a groundmass of quartz, sanidine, oligoclase, topaz and micaceous minerals and minor accessory phases. The composition is peraluminous to metaluminous, with very high Nb, Ta (Fig. 2), low LREE values and flat REE patterns. The andesites and dacites range in silica from 59 to 63 wt% and belong to the high-K calcalkaline series (Fig. 2). Their incompatible trace element spiderdiagrams show the moderate Nb and Ta and Ti troughs of subduction-related andesitic magmas (Fig. 2), suggesting a calcalkaline mantle source.
The topaz rhyolites are unrelated to the andesitic magmas in terms of fractional crystallization and crustal assimilation. On the other hand, they do not correspond to the S-type silicic peraluminous magmas of crustal derivation, requiring an igneous protolith rather than of a pelitic one (Taylor and Fallick, 1997). Other rhyolitic lavas with magmatic topaz of the western United States and Mexico show the same major and trace elements characteristics (Christiansen et al., 2007). Petrologic studies explained the North America rhyolites with melting of continental crust intruded by mafic magmas with an intraplate signature (Christiansen et al., 2007; Rodríguez-Ríos et al., 2007), in agreement with their intraplate setting. Very similar tectono-magmatic conditions are found also for the topaz rhyolites of Chivinar, in the Central Andes. In fact, the main structures controlling the rhyolitic volcanism of Chivinar may be mostly related to the back-arc transtensive conditions of COT (Acocella et al., 2011), rather than to the arc structures. Even though the overall tectonic setting of the Central Andes is contractional, transtensive or extensional conditions are found along the NW-SE trending fault zones in the back-arc, as the transtensive COT (e.g. Riller et al., 2001). In this context, the compositional features of the Chivinar topaz rhyolites (Fig. 2) could indicate partial melting of a continental crust previously intruded by mafic igneous bodies in an extensional regime, similarly to the North America topaz rhyolites. These similarities suggest a connection between the transtensive/extensional features of the COT and intraplate extensional settings elsewhere, indicating that the eruption of rhyolitic magmas suitable to the crystallization of magmatic topaz is favoured by this tectonic regime
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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