1,721,040 research outputs found
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
Mineralogical and chemical evolution of ochreous precipitates from the Libiola Fe–Cu-sulfide mine (Eastern Liguria, Italy)
No full textAppropriate 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
The role of AMD secondary minerals in controlling environmental pollution: Indications from bulk leaching tests
No full textWeathering of sulphide minerals produces a large variety of Fe-oxide-bearing ochreous, varicoloured precipitates and efflorescences of variably soluble sulphate salts. These secondary minerals play an important role in acid mine drainage processes and, more generally, for environmental pollution, since they can be either a sink or a source for acidity and toxic metals. At Libiola mine, eastern Liguria (Italy), the secondary minerals directly form through precipitation from acid sulphate waters within waste-rock dumps and outcropping mineralized bodies as well as within streams and runoff channels. Within waste-rock dumps they are present mainly as cement, filling the inter-clast porosity, and/or as coating and ephemeral efflorescences on the outcropping surfaces. Their stability represents a major environmental issue due to the potential importance of these phases in controlling metal distribution in the surface environment. This paper presents a detailed mineralogy and geochemistry characterisation of these materials, investigating the tendency for different types of secondary minerals (hardpans, ochreous consolidated precipitates, ochreous colloids, non ochreous colloids) to release metals after a simple mixing with deionised water for 12. days. Within the different types of deposits, hardpans showed the lowest tendency to release metals, in contrast to ochreous colloids and ochreous concretions that gave the highest concentrations.Nickel was the element most easily extracted by this treatment, even from non-ochreous colloids, while iron was much less readily leached. Dissolution experiments carried out on efflorescent sulphate salts demonstrated that these materials have a strong acid producing affinity which led to their complete dissolution. These results indicate that secondary phases associated with acid mine drainage can play an important role in controlling trace metal mobility, acting either as scavengers, to remove metals, from solutions or also as secondary sources of metal contamination during the interaction of these materials with surface waters
Mineralogical and chemical evolution of ochreous precipitates from the Libiola Fe-Cu-sulphides Mine (Eastern Liguria, Italy).
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