1,721,103 research outputs found
First record of the alien leech Myzobdella lugubris Leidy, 1851 (Hirudinea, Piscicolidae) in the Palearctic.
Full text linkIn this study, we report the occurrence of the Nearctic leech Myzobdella lugubris in a brackish water body of the Riserva Naturale dello Stato "Le Cesine" (Apulia, Italy). Two specimens of the species were collected in October 2016 from the neck and the forelimbs of a European pond turtle, Emys orbicularis hellenica, and identified both based on morphology and molecular sequence data. In its native range, M. lugubris is known to be a host and vector of bacteria and viruses, among which some serious fish pathogens. In light of the possible noxious ecological effects exerted through pathogen spillover on autochthonous vertebrates, the distribution of the species and its possible role as a vector of pathogens m the invaded area should be urgently monitored
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
Population abundance, structure and movements of the European pond turtle, Emys orbicularis (Linnaeus 1758) based on capture-recapture data in a Venice Lagoon wetland area, Italy
No full textA freshwater turtle monitoring programme along the inland margins of the Venice lagoon was initiated in 2019 in collaboration with the World Wild Fund for Nature (WWF-Italy). From a total of 336 European pond turtles (Emys orbicularis) captured and marked, 97 freshwater turtles were recaptured at least once (28.9% return rate) providing important information on population size, structure and movements of mature individuals within the study area. The population size was estimated with capture-recapture method (Capture-Mark-Recapture-CMR) at 1009.4 ± 365.2 pond turtles, with a mean density of 252.3 ± 91.3 ind./ha. The analysis of the movements showed that the average distance covered intra-water bodies was: 146.79 ± 117.08 m for females and 125.43 ± 112.34 m for males. A total of 17 E. orbicularis (eight females and nine males) out of 97 turtles changed the water body during the study period from April to early September. Only a female freshwater turtle migrated in all three study sites, being recaptured 1502.32 m from the tagging site. The percentage of captures was significantly higher in two canals than in the brackish lake habitat. Further research should address spatial distribution at a finer scale to evaluate the preferential habitat for threatened E. orbicularis populations in a transitional water system as the lagoon
Male mating tactics and secondary sexual traits: insights from the Mediterranean killifish, Aphanius fasciatus
Full text linkContext. Sexual selection results from male competition and female choice linked by complex interactions that drive the population’s life history, often leading to the development of specific secondary sexual traits with an increased reproductive success. Aims. To investigate the male mating tactics and the role of a secondary sexual trait (‘black band’ on the caudal fin) along the male ontogenetic development in the Mediterranean killifish, Aphanius fasciatus (Valenciennes, 1821). Methods. Male–male competition was investigated through a combination of an extensive field collection and behavioural analysis under controlled conditions, comparing four groups differing in the presence or absence of the black band and body size. Key results. Banded males courted more and tended to monopolise the female, but the overall spawning performance did not differ significantly among the analysed groups. Conclusion. (1) The black band on the caudal fin depends on ontogeny; (2) all mature males express the entire courtship and competitive repertory; (3) sexual maturity occurs in fish of at least 20 mm; (4) large size and presence of the black band seem to contribute to male dominance. Implications. This study has highlighted the role of Aphanius fasciatus as an excellent model for studying polygynandrous mating systems, on the basis of intense male–male competition
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
Terminal Strombolian activity at Etna's central craters during summer 2012: The most CO2-rich volcanic gas ever recorded at Mount Etna
No full textBy using a permanent network of multi-component gas analyzer systems (Multi-GAS), we report for the first time the H2O-CO2-SO2 composition of the volcanic gases emitted prior to, during, and after terminal Strombolian activity at Mount Etna's central craters (CCs). We show that the summer 2012 Strombolian episodes of the Bocca Nuova crater (BNC), the largest of Etna's CCs, are associated with the emission of the most CO2-rich gas measured at the volcano thus far. The BNC plume was particularly CO2-rich with CO2/SO2 up to 100, H2O/CO2 1 prevailed at the BNC and at other degassing vents such as Voragine and Northeast craters during Strombolian eruptions. Based on the results of numerical simulations of volcanic degassing, conclude that the shallow Etna plumbing system was invaded in summer 2012 by a CO2-rich gas front likely supplied by the deep (>100 MPa pressure) volcano's magmatic storage zone. This deep gas-bubble supply eventually caused a general rejuvenation of the resident magma in the upper conduits/shallow reservoirs, thereby triggering the first Strombolian episodes on the volcano's summit after years of quiescence
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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