1,721,359 research outputs found
Genetic diversity and phylogeography of the European roe deer: the refuge area theory revisited
No full textThe extant taxa of central and northern Europe are commonly believed to derive from Pleistocene ancestors, who moved to the north from three separate glacial refugia: the Iberian and Italian peninsulae, as well as the southern Balkans. The issue of postglacial dispersal patterns was addressed through the investigation of population structure and phylogeography of the European roe deer, Capreolus capreolus. The genetic diversity in 376 individuals representing 14 allegedly native populations across their European range was assessed, using ten autosomal microsatellite loci and restriction fragment length polymorphisms of the mitochondrial D-loop and NADH dehydrogenase 1 gene segments. Our results suggest the existence of three major genetic lineages of roe deer in Europe. One comprises populations in the south-western limit of the species’ distribution (i.e. Iberia), where an internal substructure splits a northern from a southern sublineage. A second lineage includes populations of southern and eastern Europe, as well as a separate sublineage sampled in central-southern Italy, where the existence of the subspecies Capreolus c. italicus was supported. In central-northern Europe, a third lineage is present, which appeared genetically rather homogeneous, although admixed, and equally divergent from both the eastern and western lineages. Current patterns of intraspecific genetic variation suggest that postglacial recolonization routes of this cervid to northern Europe could be due to range expansion from one or more refugia in central-eastern Europe, rather than proceeding from the Mediterranean areas
Girau reverter, J. (Dir.), Torrijos Castrillejo, D. y Neuman Lorenzini, R. (Eds.) (2024): La universidad en España y en el pensamiento español
No full textEste artículo reseña: Girau reverter, J. (Dir.), Torrijos Castrillejo, D. y Neuman Lorenzini, R. (Eds.) (2024): La universidad en España y en el pensamiento español. Madrid, Ediciones Universidad San Dámaso y Editorial Sindéresis
The re-discovery of the Italian roe deer: genetic differentiation and management implications
No full textGenetic diversity and differentiation were assessed in 12 populations of roe deer, Capreolus capreolus, from Italy, through examination of restriction fragment length polymorphism of two segments in the mitochondrial genome, the D-loop and NADH dehydrogenase 1, and analysis of 13 microsatellite loci. Both methods yielded concordant results and provided evidence for the existence of two genetically distinct lineages of roe deer in the Italian peninsula. One lineage occurs in populations of the Alpine arc, whilst the other is found in those of central-southern Italy, where the existence of subspecies C. c. italicus had been previously proposed. This southern lineage could have a more ancient origin or, alternatively, diverged as a consequence of movements of populations southwards during the Late Pleistocene. The unexpected rediscovery of dense populations of C. c. italicus in southern Tuscany marks them as the most suitable source of roe deer for reintroductions into southern Italy, a very large area where presently the Italian roe deer is nearly extinct. A Bayesian approach to microsatellite data allowed a finer resolution of population structure, indicating that some populations in central Italy, as well as in the western Alps, are admixed, and share ancestry partly in non Italian gene pools, suggesting that human manipulation has greatly affected the natural genetic structure of populations. A palaeontological perspective of the former presence of roe deer in Italy and implications for the management and conservation of C. c. italicus are provided. © 2002 Taylor & Francis Group, LLC
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
Reti sociali e diffusione della conoscenza nei cluster: un modello di simulazione
No full textNo abstract availabl
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
- …
