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Phylogeographic inferences on the native brown trout mtDNA variation in central Italy
No full textGenetic diversity was analysed in Salmo trutta populations living in an area of central Italy by sequencing 310 bp of the 59
end of the mtDNA control region (D-loop) and by Restriction Fragment Length Polymorphism (RFLP) analysis of three
mtDNA segments. Data show a genetic structure profoundly altered by stockings with allochthonous material of Atlantic
origin. In fact, 15 of the RFLP haplotypes detected are linked to an Atlantic sequence. The remaining 9 were instead
coupled with sequences representing the three major phylogenetic lineages previously identified in the Mediterranean basin
(Adriatic, marmoratus, and Mediterranean), representing the native genetic diversity of brown trout in that area. The close
genetic affinity observed between these latter haplotypes and those found in the Balkan peninsula by other authors seems to
be in accordance with a recent, natural, history of dispersion between the two borders of the Adriatic Sea. These results
appear significant from a conservation point of view as, in spite of the massive stocking with hatchery-reared specimens, they
highlight the persistence of Salmo trutta native genetic diversity in central Italy
Genetic diversity of brown trout (Salmo trutta L., 1758) in central Italy.
No full textGenetic diversity was analysed in brown trout Salmo trutta populations living in an area of central Italy using RFLP analysis of two mtDNA segments and of the nuclear locus LDH-C1*. The data indicated a genetic structure profoundly altered by repeated stockings with allochthonous material of Atlantic origin. In fact, four and 11 of the haplotypes detected were, respectively, identical or genetically very close to haplotypes found in Danish populations, the putative source of stocked brown trout. Furthermore, the LDH-C1*90 allele, typical of north-western Europe, was widespread among the samples studied. Nonetheless, four populations are characterized by a high frequency of both putative autochthonous haplotypes and the LDH-C1*100 allele, common in the Mediterranean basin. These populations, sampled in areas where S. trutta is documented historically, might represent a remnant of the species' indigenous biodiversity, showing the scope for improving the management of brown trout in central Italy
Presenza di aplotipi “marmoratus” in popolazioni di trota fario (Salmo trutta L., 1758) dell’Italia centrale: transfaunazione o paleointrogressione?
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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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