1,720,957 research outputs found
Sexual dimorphism in the Moorish gecko (Tarentola mauritanica, Gekkota, Phyllodactylidae): body size and head shape characteristics
No full textTwo main adaptive hypotheses are invoked for the evolution of SD: sexual selection and natural selection. In snakes SD is generally interpreted as the adaptation of the two sexes to different ecological niches, whereas in lizards sexual and ecological causes may work simultaneously, with different outcomes according to taxonomic group. Surprisingly, geckos have been almost ignored in the general debate over the evolution of SD, despite their being an extremely diversified taxon with over 1300 species showing a wide range of variability in SD. The Moorish gecko is one of those species whose dimorphism is poorly studied. We took an integrated approach using a linear (biometrical) analysis on head and body size of 157 geckos and a relatively new analytical approach (geometric morphometry) to assess head size of 38 geckos from central Italy. Males were, on average, larger and heavier than females, and body size relationships differed between age classes showing a significant SD between sexes. When controlling for snout to vent length, sexes differed only in body mass and eye diameter (larger in males). Head shape, on the contrary, showed differences according to age classes, with deep differences in hatchlings compared to adults and, among adults, between sexes. However, the growth trajectories did not differ among sexes, and SD of head shape is probably due to a more prolonged growth of the males with respect to the females. The male-biased pattern of SD in this species is most parsimoniously interpreted as the result of sexual selection, whereby larger head and body size probably confer a greater advantage to males during combats and courtship, rather than conferring independent adaptations to different ecological pressures to each sex
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
Advances in methodologies of sexing and marking less dimorphic gekkonid lizards: the study case of the Moorish gecko, Tarentola mauritanica
No full textNovelties in systems of sexing and marking less dimorphic species of gekkonid lizards are described and first
results are presented on the Moorish gecko, Tarentola mauritanica, used as target and model species. Inspection of cloacal
opening and tail basis to detect hemipenes has been done with a small probe and with laser light. Behavioural response to tail
basis touch was typical of adult males. Permanent marking has been performed along with the removal of some subdigital
scales. Sexing was suitable and feasible on all individuals larger than 45 mm snout to vent length
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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