1,720,971 research outputs found
Re-examination of fluosiderite, an unknown mineral from southern Italy: equal to fluorine-rich
No full textThe “calamine” of SW Sardinia (Italy): geology, mineralogy and stable isotope geochemistry of a supergene Zn-mineralisation.
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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
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
X-ray diffraction and scanning electron microscopy quantitative mineralogical evaluation of the karst bauxite deposits in Campania, southern Italy
No full textBauxite resources in the world are estimated to be between 55 to 75 billion tons, occurring in Africa (32%),
Oceania (23%), South America and the Caribbean (21%), Asia (18%) and elsewhere (6%) (United States Geological Survey Minerals Yearbook, 2011). These resources are mostly used to produce alumina for metallurgical purposes. Approximately 70 to 80% of the world’s bauxite production is processed first into
alumina (Bayer process) (Hind et al., 1999), and then into aluminium by smelting and electrolysis (Hall– Herault process). The mineralogical variation in the composition of bauxite can affect the Bayer process, e.g. the effect of reactive silica, which contaminates the aluminium extraction process, and titanium minerals, which reduce the efficiency of the Bayer Process (Dudek et al., 2012; Smith, 2009). In this study, mineralogical characterization of some bauxite occurrences in Southern Italy has been carried out, including a comparison of results obtained from the quantitative analysis of the ore using the classic XRD-QPA (X-ray diffraction-quantitative phase analysis) method, and QEMSCAN (quantitative evaluation of minerals by scanning electron microscopy) automated technology, which represents a mineralogical investigation tool common-used in the bauxite industry (Goodall et al., 2005). The bauxite of Southern Italy that is presently uneconomic can be considered as a model analogue for economic karst bauxite ores. Several bauxite occurrences from two former mining districts in Southern Apennines (Matese Mts. and Caserta province) have been analyzed. XRD-QPA allowed an exact evaluation of the amounts of minerals occurring in the bauxite. The main Al-rich mineral is boehmite, whereas the most common silica-bearing phase is kaolinite. Hematite is the main Fe-bearing mineral. Goethite also occurs, as well as sporadic lepidocrocite. Anatase and rutile are quite ubiquitous. QEMSCAN was used in the fieldscan mode and allowed: (1) the identification and Abstracts classification of the mineralogical phases on the basis of their chemical composition, and (2) the abundance of these phases. Moreover, this technique has provided evidence of the textural characteristics of the ore that can be important in the Bayer process. In particular, it has been possible to determine that boehmite, which tends to be more concentrated in the ooids than in the matrix, contains variable amounts of Fe. Hematite occurs solely as detrital elements, kaolinite occurs mainly in the bauxite matrix and, Ti-oxides are generally associated with goethite and hematite. Comparison between the XRD quantitative mineralogical analyses and the corresponding analyses determined by QEMSCAN shows convergent results (Boni et al.). The XRD quantitative evaluation of bauxite phases gives useful constraints for the interpretation of QEMSCAN raw data, which may be very detailed but cannot separate polymorphous minerals that occur in bauxite. Furthermore, QEMSCAN quickly highlights the main textural characteristics of the bauxite, which can affect the Bayer process, but there are also some problems in identifying the composition of phases that have a grain size lower than the provided scanning resolution. However, by using both methods, and with the support of manual SEM (scanning electron microprobe), all the issues were isolated and resolved. For this reason the XRD-QPA and QEMSCAN techniques should be considered complementary for bauxite ore evaluation, and can provide a very powerful tool for their exploitation and mineral processing
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