1,720,954 research outputs found
Evolution of the mafic Villa Senni caldera-forming eruption at Colli Albani volcano, Italy, indicated by textural analysis of juvenile fragments
No full textThe Villa Senni Formation (355 ka) represents the youngest mafic caldera-forming eruption of the Colli
Albani Volcano (Central Italy), and one of the best exposed large mafic ignimbrite successions on Earth. The
unusual Si-undersaturated and high-K composition of the magma, and corresponding low magma viscosity,
raise important questions about the conditions of magma ascent, eruption, and fragmentation that led to
such a large explosive eruption. We examined the juvenile clast textures – that is, the abundance, shape, size
and number density of both vesicles and leucite microlites – to reconstruct the fragmentation conditions and
to trace major changes in the ascent rate and vesiculation history of the magma associated with caldera
collapse. The juvenile textures record two major changes in the eruption dynamics through the stratigraphy.
First, the sudden depressurization of the magma chamber and the onset of the first ignimbrite-forming phase
are marked by a dramatic increase in the magma ascent velocity inferred by a decrease in vesicle and leucite
microlite sizes and increase in their number densities. Second, the progressive restoration of pressure within
the magma reservoir as a consequence of caldera collapse is recorded by an inversion of vesicle and leucite
microlite textures, which suggest a strong decrease in magma ascent rate. Complex vent conditions in this
later phase of the caldera collapse are recorded by the diversity of textural features, variation in magma
chemistry and the abrupt changes in the stratigraphic record (including the presence of co-ignimbrite
breccias, spatter clasts and lithics)
Inception of mafic, explosive caldera-forming eruptions: the basal fallout deposits of the "villa senni" (355 ka) and "pozzolane nere" (407 ka) eruptions at "colli albani" volcano (italy)
No full text
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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