1,720,985 research outputs found
Storia di due (o più) «ritorni» (prefazione al romanzo di Folco Giusti, L’isola dell’ultimo ritorno, Padova, Primiceri Editore, 2020)
No full textLa prefazione colloca il romanzo di Folco Giusti nell'ambito della produzione narrativa che riguarda la tarda antichità, e in particolare di quella che si interessa del poemetto "De reditu" di Rutilio Namaziano. Il romanzo infatti parte da questa importante figura della poesia tardolatina
Molecular phylogeny and historical biogeography of the land snail genus Solatopupa (Pulmonata) in the peri-Tyrrhenian area
Full text linkThe land snail genus Solatopupa consists of six species and has a peri-Tyrrhenian distribution; most of the species have a very narrow range and all of them except one (Solatopupa cianensis, which inhabits porphyritic rocks) are strictly bound to calcareous substrates. One species (Solatopupa guidoni) is limited to Sardinia, Corsica, and Elba Island. Because the potential for dispersal of these snails is low, the insular range of this species has been traditionally related to the Oligocenic detachment of the Sardinia-Corsica microplate from the Iberian plate and its subsequent rotation towards the Italian peninsula. In this study, we used sequences of three mitochondrial and one nuclear gene to reconstruct the evolutionary history of the genus. Our phylogenetic results are consistent with the genetic relationships found using allozymes, but contrast with the phylogenetic hypotheses based on karyology and morphology. Molecular clock estimates indicate that the main cladogenetic events in the genus occurred between the middle Miocene and the middle-late Pliocene. Patterns of phylogenetic relationships and geological considerations suggest that the cladogenesis of the genus can be explained by vicariant (tectonic) processes. Our datings do not support a causal relation between the split of S. guidoni from its continental sister taxon and the initial phases of the detachment of the Corsica-Sardinia microplate from the mainland. On the contrary, time estimates coincide with the very last phase of detachment of the microplate (from 5 to 3 Myrs ago). Overall, our molecular clock estimates are in good agreement with the latest geological views on the tectonic evolution of the peri-Tyrrhenian area. © 2005 Elsevier Inc. All rights reserved
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
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
Peri-Tyrrhenian phylogeography in the land snail Solatopupa guidoni (Pulmonata)
Full text linkThe land snail Solatopupa guidoni has an interesting disjunct distribution in the peri-Tyrrhenian area, with a few scattered populations in Sardinia, Corsica, and Elba Island. The species is strictly bound to limestone and has poor dispersal capacity. Here, we used sequences of two mitochondrial genes, cytochrome oxidase I (COI) and 16S rRNA (16S), to reconstruct the species phylogeography. The study is based on nine of the 13 populations reported in the literature. Phylogenetic methods and nested clade analysis failed to retrieve reciprocally monophyletic lineages on each island. Sardinian and Elba Island populations were found to be embedded within those of Corsica. These results contrast with previous phylogeographic studies of other organisms with similar distribution patterns, showing major phylogeographic breaks between islands. Molecular clock estimates suggest that species diversification occurred less than 2.5 Myr ago, in line with a previous study that dated the split of S. guidoni from its continental sister species at 3-5 Myr. Corsican populations can be tentatively sorted into two haplo-groups. A first group includes haplotypes found in central inland Corsica only, whereas haplotypes found in northern coastal locations cluster in a second haplo-group. The latter also includes Sardinian and Elba Island populations. Molecular data indicate that a combination of vicariance and dispersal events provide the best explanation of the distribution of this species
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