1,721,076 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
Los mapas geomorfologicos de la Antartida. Analisis comparativo. The geomorphological maps of Antarctica. Comparative analysis.
No full textFor the first time, all the existing geomorphological maps of Antarctica published as independent documents have been compiled and analysed comparatively. The maps have been grouped into two categories: (1) geomorphological maps in the strict sense (s.s.) from which one can obtain information about the dimension, geometry, origin and in some cases, the age of the landforms and mapped deposits; (2) thematic geomorphological maps which represent a limited number of geomorphological elements and morphogenetic environments. The geomorphological maps s.s. have been classified into four types according to different graphic representation, and also for the importance assigned to the genesis of landforms, to morphography and lithology: Morphostructural maps, that show the main morphostructures; Morphochronological maps which do not adopt the genetic classification of the landforms, but use different colors to discern the chronological distinction of the deposits; Geomorphological-morphographic maps, that indicate the morphography and genetic representation of landforms by areas of geomorphological processes; Morphogenetic-morphodinamic maps with chronological elements, that pay particular attention to morpho-genesis and to the lithological nature of the bedrock. In total, 10 geomorphological maps s.s. and 6 geomorphological thematic maps have been analysed. Of the 16 maps considered, 11 correspond to the East Antarctica, 2 to the West Antarctica, 2 to the subantarctic islands and 1 dealing the mostly part of the continent. It is confirmed that the majority of the geomorphological maps s.s. relate to partially deglaciated coastal areas, only 2 correspond to continental zones, that exist 17 686 km2 mapped to medium or relatively detailed scale (from 1:20 000 to 1:250 000). These figures provide an idea of the small proportion of the Antarctic territory for which geomorphological maps already exist, in spite of the numerous studies that have already been done since the first scientific expeditions
Human-induced hazardous debris flows in Carrara Marble basins (Tuscany, Italy)
No full textIn Carrara marble basins, the long and intensive quarrying activities (which began in the first century BC) have produced
extensive dump deposits, locally known as ravaneti. Ravaneti are of such large dimensions and diffusion as to make them a
widespread landform of the Apuane Alps (Tuscany). In recent years these quarry dump deposits have been affected by
frequent debris flows, more than 50 in 1996/97. This phenomenon is the most significant currently active geomorphological
process in this landscape.
The evolution of quarrying techniques produced a variety of sedimentological compositions of ravaneti. The debris
flows analysed involve only the surface layers where debris is mixed with fine material with a lower permeability (active
ravaneti) than the coarser underlying debris (older ravaneti). The presence of different permeability layers causes a
wetting front to move downwards. Source area observations indicate a soil slip movement in the initial phases of the
failure. The transformation of landslides into debris flow occurs by means of both soil contractive failure and an increase
of granular temperature.
The morphological and sedimentological analyses of depositional lobes resulted in a classification of three types of
lobe, based on fabric±morphometry relationships allowing the identification of different flow dynamics: (1) type A lobe
(platy form), matrix-supported and well developed fabric with general tendency of ab clast plane strikes to lie generally
parallel to flow direction as a consequence of laminar flow; (2) type B lobe (elongated form), clast-supported and random
fabric as a consequence of both turbulent flow and coarser composition of starting material; (3) type C lobe, intermediate
type A±B morphometry, tendency for ab clast plane to lie in a semi-circle around the main flow direction determined by
the presence of secondary flow lines divergent from it in the stopping phase.
In Carrara marble basins, the anomalous frequency with which debris flows tend to be triggered by medium-intensity
rainstorms (about 30 mm hÿ1 rainfall) is due to the recent increases in silt dump produced by modern quarrying
techniques. This represents a significant example of debris flows as an environmental problem in major anthromorphized
landscapes. Copyright # 2000 John Wiley & Sons, Ltd
Review of Antarctic geomorphological mapping
No full textFor the first time, all the existing geomorphological maps of Antarctica published as independent documents have been compiled and analysed comparatively. The maps have been grouped into two categories: (1) geomorphological maps in the strict sense (s.s.) from which one can obtain information about the dimension, geometry, origin and in some cases, the age of the landforms and mapped deposits; (2) thematic geomorphological maps which represent a limited number of geomorphological elements and morphogenetic environments. The geomorphological maps s.s. have been classified into four types according to different graphic representation, and also for the importance assigned to the genesis of landforms, to morphography and lithology: Morphostructural maps, that show the main morphostructures; Morphochronological maps which do not adopt the genetic classification of the landforms, but use different colors to discern the chronological distinction of the deposits; Geomorphological-morphographic maps, that indicate the morphography and genetic representation of landforms by areas of geomorphological processes; Morphogenetic-morphodinamic maps with chronological elements, that pay particular attention to morpho-genesis and to the lithological nature of the bedrock. In total, 10 geomorphological maps s.s. and 6 geomorphological thematic maps have been analysed. Of the 16 maps considered, 11 correspond to the East Antarctica, 2 to the West Antarctica, 2 to the subantarctic islands and 1 dealing the mostly part of the continent. It is confirmed that the majority of the geomorphological maps s.s. relate to partially deglaciated coastal areas, only 2 correspond to continental zones, that exist 17 686 km2 mapped to medium or relatively detailed scale (from 1:20 000 to 1:250 000). These figures provide an idea of the small proportion of the Antarctic territory for which geomorphological maps already exist, in spite of the numerous studies that have already been done since the first scientific expeditions
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
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