1,720,977 research outputs found
Re-equilibration of primary fluid inclusions in peritectic garnet from metapelitic enclaves, El Hoyazo, Spain
No full textPrimary-appearing fluid (Fl) and melt (FI) inclusions occur in peritectic garnet from restitic enclaves from El Hoyazo (Spain). The inclusions were trapped under conditions of immiscibility during partial melting of the enclaves. Trapped fluids in Bt-Grt-Sil and Spl-Crd enclaves have been characterized by microthermometric. Raman spectroscopic, electron microprobe (EMP) and transmission electron microprobe (TEM) analyses to better constrain melt and fluid products and pressure conditions of the partial melting event. In Bt-Grt-Sil enclaves, Fl are one phase and contain a CO(2)-N(2) mixture, sometimes with graphite as trapped phase. In Spl-Crd enclaves, Fl are two phase and contain an H(2)O-rich (<= 90 mol%), with minor amounts of CO(2), N(2), and traces of H(2)S and CH(4). Graphite often occurs as a trapped phase in the H(2)O-rich Fl, and rare carbonates and other accessory minerals are also observed. Although decrepitation features are not recognized during examination with a petrographic microscope, Fl densities based on mass balance constraints are always lower than expected at the inferred PT conditions of entrapment, 5-7 kbar and 800-900 degrees C. Extremely low densities (approximate to 0.1 g cm(-1)) of Fl in Bt-Grt-Sil enclaves suggest a pressure <= 500 bar at 800-900 degrees C, while densities up to 0.53 g cm(-1) in Spl-Crd enclaves indicate P kbar at 800-900 degrees C. Re-equilibration is likely to have occurred via partial decrepitation, as suggested by TEM studies that show rare partially annealed sub-pm cracks, containing small cavities, which may have been the pathways for fluid movement out of the inclusions. MI coexisting with Fl have a rhyolitic, peraluminous composition, with higher H(2)O contents of MI in Spl-Crd enclaves (approximate to 9 wt.%) compared to MI in Bt-Grt-Sil enclaves (approximate to 3 wt.%). Based on published data, peritectic garnet in Spl-Crd enclaves grew in the presence of a leucogranitic melt saturated in an H(2)O-rich fluid, in good agreement with the inferred garnet PT growth conditions. The composition of the fluid phase coexisting with melt in Bt-Grt-Sil enclaves cannot be evaluated owing to the almost complete decrepitation and fluid loss from Fl, and may only be inferred to have been more CO(2)-rich, based on the lower H(2)O content of the coexisting melt
Source of magmas that generated eruptive products at Mt. Somma-Vesuvius and Campi Flegrei based on melt inclusions
No full textDefinizione e discussione sulle sorgenti magmatiche attraverso lo studio delle melt inclusions del Vesuvio e dei campi Flegre
Nanogranite inclusions in migmatitic garnet: behavior during piston cylinder re-melting experiments.
No full textGoing 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
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
Ascent magmas associated with the Solchiaro eruption Procida Island (Italy) based on melt inclusions and glasses
No full textValutazione di risalita di magmi durante l'eruzione di Solchiaro, Procida, Campi Flegrei attraverso lo studio di melt inclusion
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