1,720,984 research outputs found
Cuirasses ferrugineuses et encroûtements calcaires au Sénégal occidental et en Mauritanie. Systèmes évolutifs : géochimie, structure, relais et coexistence
No full textNahon Daniel. Cuirasses ferrugineuses et encroûtements calcaires au Sénégal occidental et en Mauritanie. Systèmes évolutifs : géochimie, structure, relais et coexistence. Strasbourg : Institut de Géologie – Université Louis-Pasteur, 1976. 272 p. (Sciences Géologiques. Mémoire, 44
Géochimie de la surface, pédogenèse, aplanissements et formes du relief dans les pays méditerranéens et tropicaux
No full textMillot Georges, Bocquier Gérard, Boulet René, Chauvel Armand, Leprun Jean-Claude, Nahon Daniel, Paquet Hélène, Pédro Georges, Rognon Pierre, Ruellan Alain, Tardy Yves. Géochimie de la surface, pédogenèse, aplanissements et formes du relief dans les pays méditerranéens et tropicaux. In: Phénomènes de transport de matière dans l'écorce terrestre. ATP - CNRS. Action thématique Programmée du Centre National de la Recherche Scientifique. Résultats scientifiques. Strasbourg : Institut de Géologie – Université Louis-Pasteur, 1979. pp. 39-43. (Sciences Géologiques. Mémoire, 53
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Mineralogical evolution of supergenic alteration in alkaline rocks of Lages, southern Brazil
No full textThe District of Lages (SC Brazil) is the southernmost known bauxite deposit of Brazil. Mineralogical and chemical changes of phonolites show that nepheline is the first mineral to change, releasing sodium first and potassium and silicon later. The alteration of nepheline forms dissolution cavities which highly increase rock porosity. In some cases gibbsite partially or entirely fills the cavities. Globular material is found side by side with large crystals of gibbsite on the corroded K-feldspar. The advanced alteration of feldspar converges to gibbsite in the final stage but locally shows an intermediate silico-aluminous phase. Pyroxenes are altered to goethite along the cleavage and parting planes at first and are almost completely replaced in more advanced stages of alteration. Later veinlets of white halloysite and lithiophorite run accross the entire weathering profile.Formoso M.L.L., Nahon Daniel, Novikoff André, Valeton Ida. Mineralogical evolution of supergenic alteration in alkaline rocks of Lages, southern Brazil. In: Proceedings of the 9th international Clay Conference, Strasbourg, 1989. Vol I : Clay-organic interactions. Clay minerals in soils. Strasbourg : Institut de Géologie – Université Louis-Pasteur, 1990. pp. 165-173. (Sciences Géologiques. Mémoire, 85
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Nodules et pisolites de dégradation des profils d'altération manganéslfères sous conditions latéritiques. Exemples de Côte d'Ivoire et du Gabon / Nodules and pisolites from manganlferous weathering profiles under lateritic influences. Examples from Ivory Coast and Gabon
No full textManganiferous pebbly horizons overlying lateritic weathering profiles in Ziemougoula area (Ivory Coast) and Moanda area (Gabon) are essentially made up of Mn-nodules and pisolites. They were studied from a petrological and mineralogical point of view. These nodules and pisolites consist of concentric cortical layers developed, through centripetal way, at the expenses of cores which are inherited from underlying indurated mangan cretes. The small-sized pisolites with a well-developed concentric cortical layer are originated from bigger nodules with a well-developed core. Generally, the core of the nodule shows a preservation of structures preexisting in underlying horizon, and in which parent mineral relicts since occur. Such preserved structures and mineral relicts are replaced by concentric structures of cortical layers. Through that evolution between the core and the cortical layer and between the nodules and the pisolites, Mn-oxihydroxides and Al-oxihydroxides are progressively separated from each other from successive centripetal reorganizations (dissolutions and precipitations). This enrichment into Al with regard to Mn occur at different scales of observation : between the nodules and the pisolites, between the cortical layer and the core, between each layer of a same cortical layer, and result from the behaviour of these two elements in different geochemical environments : Mn concentrates in confined environment i.e. in cryptovoids, Al concentrates in more diluted environment i.e. in micro and macrovoids.Les nodules et pisolites manganésifères des horizons caillouteux différenciés in situ au sommet des profils d'altération supergène et latéritique de Ziémougoula (Côte d'Ivoire) et Moanda (Gabon) ont été étudiés d'un point de vue minéralogique et pétrologique. Ils sont constitués d'un cortex rubané, qui se développe par accrétion centripète aux dépens d'un coeur hérité des horizons indurés d'accumulation manganésifère sous-jacents. Une relation d'ordre chronologique et génétique existe entre les nodules les plus gros possédant un coeur relictuel à minéraux manganésifères altérés et un faible cortex rubané, et les pisolites de plus petite taille constitués essentiellement d'un cortex bien développé, également manganésifères mais fortement enrichis en alumine. Au cours de cette évolution entre coeur et cortex et entre nodules et pisolites, les oxy-hydroxydes essentiellement manganésifères et les oxy-hydroxydes essentiellement alumineux se différencient nettement au gré des dissolutions et recristallisations, sans cesse réitérées. Cette différenciation entre Mn et Al s'observe à toutes les échelles et correspond à deux milieux géochimiques qui s'opposent : l'un, confiné dans les cryptovides, concentre le manganèse, l'autre, plus lessivant dans les micro et les macrovides, concentre l'alumine.Beauvais Anicet, Nahon Daniel. Nodules et pisolites de dégradation des profils d'altération manganéslfères sous conditions latéritiques. Exemples de Côte d'Ivoire et du Gabon / Nodules and pisolites from manganlferous weathering profiles under lateritic influences. Examples from Ivory Coast and Gabon. In: Sciences Géologiques. Bulletin, tome 38, n°4, 1985. Accumulations ferrugineuses et manganésifères. pp. 359-381
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