1,720,968 research outputs found
First record of Bombina variegata (Linnaeus, 1758) in a cave environment
No full textSeveral species of amphibians are known to inhabit
subterranean habitats. While some species are obligatory
cave-dwelling (e.g., Proteus anguinus Laurenti, 1768),
others tend to use caves only for limited periods of their
lives (Peck, 1974; Romero, 2009). At least 17 species of
amphibians that belong to the Italian herpetofauna have
on occasion been found in caves or other underground
spaces and several of them occasionally breed in
subterranean sites. Here we provide the first evidence
of a population of yellow-bellied toads (Bombina
variegata) exploiting a subterranean habita
Quantitative and structural variation in skin secreted toxins across populations of the frog Bombina pachypus (Anura: Bombinatoridae)
No full textAbstract. Skin secretions of amphibians have been intensively studied because of their pharmacological properties and
their potential use in clinical applications. In many species, the substance secreted contains different peptide families, which are
stored in skin granular glands and released when the animal is stressed, for example when under attack by a predator. Although
the skin secretion of many species has been molecularly characterised, any insight in natural variation within species and/or
populations is absent. Understanding what influences natural secretion variation could improve the knowledge in evolutionary
processes and forces that drive their adaptive evolution. Here, skin secretion variation is examined in eight populations of
Bombina pachypus, broadly covering the species’ distribution range. Variation in poison production, as well as in the
concentration of the key toxin bradykinin, are examined in light of intrinsic (morphological) and extrinsic (environmental)
variables. Latitude, altitude and sexes turn out to be variables that mostly influence poison production, with an increase in poison
quantity towards the south and towards higher altitudes. Potential explanations for higher poison production in males are further
discussed
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
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