1,720,975 research outputs found
Genesi ipoabissale di fusi legati al vulcanismo alcalino potassico. II: Studio petrografico e petrologico degli inclusi termometamorfici delle vulcaniti cimine ed ipotesi genetiche
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The thermometamorphic contact aureola around the Isola del Giglio granodiorite (Tuscany, Italy): Petrography and petrogenetical considerations
No full textRicostruzione geologica del territorio di Bomarzo mediante la catalogazione dei beni delle Scienze della Terra.
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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
Amphibole asbestos from Libby (Montana, USA): mineralogical data for toxicological applications
No full textAmong the different natural and industrial materials, asbestos are still retained to be significantly dangerous for the human health and in the majority of countries their uses and manipulations are ruled out by laws (Plumlee et al., 2006). The term asbestos is generally used to describe minerals that either occur as long silky fibres or can be easily split so as to become such. The asbestos minerals are currently sub classed into two main groups: (i) serpentines (e.g. chrysotile) and (ii) amphiboles (e.g., tremolite, riebeckite). It is now retained that fibrous amphiboles are significantly more dangerous than fibrous serpentines (McDonald and McDonald, 1997; Plumlee et al., 2006). Therefore it is extremely important to characterise the fibrous amphiboles (natural and industrial) occurring in the environment as airborne dust, particularly with respect to their chemistry. However despite of a relatively large amount of medical and biochemical studies devoted to the toxicological effects of asbestos (especially on amphiboles), the mineralogical characterisation of the fibrous minerals was normally little constrained.
Several parameters can in fact be supposed responsible for their biological hazard, and these include the Fe content of the fibres, the absolute dimensions and aspect-ratio of the crystallites, the electrical surface potential, the solubility as a function of pH, and the hydrophobicity vs. hydrophilicity (van Oss et al., 1999); all these properties are notably dependent on their chemistry, and thus their knowledge is of capital importance for any investigations dealing on amphibole asbestos.
A rather rapid, complete and accurate crystal-chemical investigations of (fibrous) amphiboles can be carried out by the combination of SEM, XRPD and FTIR OH-stretching data. We checked this analytical protocol on a set of asbestos amphiboles from the Libby quarry, Montana (USA). These samples were previously studied and characterized by EPMA, Mössbauer and single crystal XRD. Our crystal-chemical results well matched with those reported in literature. This definitively indicates that the spectroscopic (FTIR) methods offer a very fast tool for a proper characterization of fibrous amphiboles in environmental monitoring.
References:
McDonald, J.C., McDonald, A.D. (1997). Annals of Occupational Hygiene, 41(6), 699-705.
Plumlee G.S., Morman S.A., Ziegler T.H. (2006). Reviews in Mineralogy and Geochemistry, vol. 64:5-57.
van Oss, C.J., Naim, J.O., Costanza, P.M., Giese, R.F. Jr., Wu, W., Sorling, A.F. (1999). Clays and Clay Minerals, 47, 697-707
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