1,721,022 research outputs found
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
Another piece of the evolutionary history of Atlantic skates (Chondrichthyes, Rajiformes ): integrating DNA barcoding approach and phylogenetic inferences
No full textConservation and long-term management plans of marine species need to be conceived upon a universally recognised key-feature: species identity. This important assignment resulted particularly arduous among skates (order Rajiformes), in which the phenotypic similarity between some taxa and the individual variability in others, entangled accurate species identification.
This study confirms the power of DNA barcoding for the discrimination between skate species across the Atlantic Ocean and for its use as effective tool to minimize the risk of species misidentification and to elucidate species boundaries. In this perspective, this work compiles and establish a new fully available and well-curated barcode library, the ELASMO-ATL project, which gathered biological and molecular information of 432 skate specimens and covered coastal waters of four FAO Major Fishing Areas (27, 34, 47, 41) of the Atlantic Ocean.
The evolutionary histories of 34 skate species were estimated with two concatenated mitochondrial markers (COI and NADH2) through Bayesian and species level phylogeny analyses. It was possible to discover a new evolutionary lineage within the genus Raja in the southern-most part of its distribution area and to enable deepening the relationship between South-African endemic species of Rajella. Once again, Western South African coasts and oceanographic fronts may play a fundamental role among skates’ speciation events in which the paleoclimatic and paleogeographic history joined to hydrography events could have contributed to the formation of refugial areas, characterised by geographical isolation. Subsequent contact zones in these areas between Senegal and Angola seems to constitute a continuum/cline of genetic change among some Raja species.
These data successfully resolved many taxonomic ambiguities and demonstrated a highly cohesive monophyletic clustering among the order laying the foundations for further inference of evolutionary patterns suitable for addressing management and conservation issue
First assessment of the genetic structure of deepwater blackmouth catshark (G. melastomus Rafinesque, 1810) in Atlantic and Mediterranean populations
No full textThe worldwide abundance of Galeus melastomus in the biological composition of fishery bycatch led to consider this species as a key-taxon for understanding the mysterious biology and ecology of sharks living in deep ecosystems. With the present work, we aim to unravel the population structure of the blackmouth catshark in the Mediterranean Sea and adjacent North-Eastern Atlantic with the use of nuclear molecular markers (simple sequence repeats, SSRs) and compare our results with recent findings based on mitochondrial DNA supporting total panmixia in the species. Given the absence of species-specific microsatellite markers we attempted the cross-amplification of a panel of 129 SSRs developed for Centroselachus crepidater, Galeorhinus galeus, Hexanchus griseus, Mustelus antarcticus, M. canis, M. henlei, M. mustelus, Negaprion brevirostris, Scyliorhinus canicula, Squalus acanthias and S. mitsukurii on blackmouth catsharks collected during scientific surveys undertaken in different years. The rationale of the chosen methodology was based on the calculation of genetic distances between NADH2 sequences (1044bp long) derived from 595 species of elasmobranchs. Our strategy focused on testing first SSRs markers developed on closely-related species. Then, we assessed highly polymorphic markers developed on non-closely-related species. After a pilot gradient amplification on few individuals from three different geographic macro-areas, we screened a total of 24 samples at the established conditions. To date, 16 microsatellite loci have been classified as potential candidates for the succesful cross-amplification on Atlantic and Mediterranean samples of G. melastomus. These candidate loci will be applied in the population genetic analysis delineated in the Atlantic Ocean (two sites) and in the Mediterranean Sea (five sites). Hopefully, the higher resolution power of the markers chosen for this study will be able to disclose any signal of genetic structure of the blackmouth catsharks and will contribute to improve the knowledge on deep-sharks
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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