1,720,983 research outputs found
Studio mineralogico delle porzioni pelitiche nelle Marne di Antognola della zona di Zocca (Modena)
No full textThe distribution patterns of clay and non-clay minerals has been studied for 30 samples from sediments NW of Zocca, using XRD and volumetric CO 2 analyses. Dioctahedral smectites are abundant and there are high volcanogenic cristobalite contents; serpentine is constantly present due to the erosion of serpentinized ophiolitic rocks during the time of deposition of these pelitic sediment
Trioctahedral smectites and zeolites as transformation products of the Cala Pozzolana di Ponente pyroclastic rocks (Linosa Island - Italy)
No full textOn Linosa Island the pyroclastites of Cala Pozzolana di Ponente have been affected by post depositional alteration phenomena. Field and laboratory study point out that this pyroclastic deposit was affected by hydrothermal circulation with formation of secondary minerals like smectite, zeolites, calcite. The transformation processes were accomplished in two stages; a first one was brought about by the circulation of abundant hydrothermal fluids that reacted with the glass fragments producing a thin regular crust of smectite surrounding glass fragments and a second one, responsible for the zeolite growth, was accomplished by fluids enriched in alkalis and calcium released by the altered glass, in conditions of decreasing fluid circulation and falling temperature. -from Author
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
Studio mineralogico-petrografico dei litotipi dell'ofiolite di Serra del Zanchetto (Bologna)
No full textMineralogical and petrographic studies of gabbros, sediments and serpentinites from an ophiolitic body at Serra del Zanchetto, Italy, are reported. Three groups are studied: 1) a mylonitized gabbro, near a gabbro-serpentinite contact, which contains serpentinite fragments, newly-formed diopsidic clinopyroxene, augite and chlorite, and shows textural characteristics which suggest strong tectonic movements following the serpentinization process; 2) a transformed coarse-grained gabbro, included in the serpentinite, which contains prehnite, after plagioclase and chlorite, after clinopyroxene; the chemical formulae of both minerals and the optical, IR and thermal behaviour of prehnite are given; and 3) fragments of sediment outcropping close to both gabbros and serpentinites. One type seems to be either a diagenetic or weakly metamorphosed arkose; a second, shows similar textures but has chloritized biotite and feldspars replaced by a regularly interstratified chlorite-saponite. The significance of the metasomatic effects of the serpentinization on gabbro xenoliths and arkosic sediments are discussed
High temperature associations in the contact aureole of Toal del Mason, Predazzo-Monzoni
No full textThe studied contacts outcrop in the upper part of the Toal del Mason and consist of two of high-temperature minerral associations, developed at the contact between the Monzoni pluton and the sedimentary country rocks of Werfenian-Anisian age. The contact metamorphites are forsterite-bearing marbles and monticellite-bearing Ca-Mg hornfels which pass to a carbonatic Ca-Mg hornfels. The whole rock and mineral phase chemistry is generally simple, with modest concentrations of trace elements which are always correlated with the crystal chemistry of the mineral phases: the main conclusion is that the metamorphic system, on the whole, was virtually closed and that the mobilisation of elements was limited to small distances involving almost exclusively the original sedimentary rocks. -from English summar
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
Generalized dystonia with bilateral striatal computed-tomographic lucencies in a patient with human immunodeficiency virus infection.
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