1,720,971 research outputs found
The intriguing Ordovician “trilobite” Tariccoia arrusensis (Arthropoda, Nektaspida, Naraoiidae) from Sardinia: new data and perspectives
No full textBiotic interactions between animals and lants in benthic marine environments dominated by echinoids and coralline red algae from the miocene of Sardinia
No full textInteraction between echinoids and coralline red alhgae. Lower Miocene rhodolith beds from Sardinia
Animal-plant interactions in the marine ralm: Echinoid-coralline algal dominated ecosystems in the Miocene of Sardinia
No full textNo abstract availabl
The turbulent path of Tariccoia arrusensis: palaeoecology of an Ordovician nektaspid endemic to Sardinia
No full textBiostratinomy and hydrodinamic behaviour of Tariccoia arrusensis: implications for depositional environment of the Riu Is Arrus Member (Upper Ordovician – SW Sardinia, Italy)
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The origin of echinoid shell beds in siliciclastic shelf environments: three examples from the Miocene of Sardinia, Italy
No full textThree mass accumulations of sea urchins from the Miocene of Sardinia show a number of taphonomic features which set them apart from previously described echinoid
assemblages from the Cenozoic in which they represent: (1) monotypic assemblages;
(2) include very well-preserved remains of either regular or spatangoid echinoids; and
(3) originate in deeper water environments. These accumulations are compared using a detailed sedimentological and taphonomic analysis including preservational fabrics, taphonomic signatures, size frequency distributions, density of occurrences and preferred orientations. The possible role of gregarious behaviour contributing to mass occurrences and the specific sedimentary events leading to the excellent preservation are discussed. The interpreted depositional environment of all three deposits is that of a storm-dominated, siliciclastic shelf environment. A phymosomatid assemblage represents rapid burial through obrution of a highly dense, freshly dead community. A Brissopsis-dominated spatangoid assemblage represents a mixed accumulation of
parautochthonous and transported skeletons. The third assemblage consisting of regular echinoid spines and rare tests represents a composite tempestite. Differences in the depositional environments are related to their position along onshore offshore gradient with the first two beds originated in a deeper setting than that of the spine accumulation. This study shows that the preservation of assemblages containing complete regular echinoids and spatangoids is higher in deeper water settings than in
shallow water environments
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
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