1,720,958 research outputs found
In search of prey: the occurrence of Alopias vulpinus in the northern Adriatic Sea and its interactions with fishery.
No full textThe common thresher shark, Alopias vulpinus, has shown a marked decline in abundance in the
Mediterranean Sea. Through the analysis of long-term fishery time series (1966–2013), this study
highlights that an important driver of the presence of A. vulpinus in the northern Adriatic Sea, one
of the most exploited basins of the Mediterranean, is the abundance of its prey, the sardine Sardina
pilchardus. From 1997-2013, an annual average of 14 thresher sharks was landed at Chioggia
(Italy), the main fish market in the area, mainly from July to October. More than 75% of the landed
thresher sharks were sexually immature, with some specimens weighing less than 10 kg, indicating
that a high proportion of the catch was composed of small young and newborn individuals. These
results support the occurrence of a nursery area in the northern Adriatic Sea, highlighting the need
for proper management of A. vulpinus catch in this area
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
Resolving the ambiguities in the identification of two smooth-hound sharks (Mustelus mustelus and Mustelus punctulatus) using genetics and morphology
No full textElasmobranch species are among themost threatened marine fish, and sound biological data for many of them are lacking. In this context, the smooth-hounds (Mustelus spp., Triakidae, Carcharhiniformes) represent an intriguing genus, being characterized by unclear and sometimes contrasting diagnostic traits. Here, we present new insights into the identification of two closely related species, M. mustelus and M. punctulatus.The use of three different molecular markers on a dataset of 588 specimens highlighted a genetic distinction between the two species. However, whereas microsatellites provided unambiguous results in all the samples, the other two markers were not able to assign a fraction of the individuals (6.6% for cytochrome c oxidase subunit 1, 14.4% for Internal Transcribed
Spacer 2), suggesting the occurrence of heteroplasmy and introgression due to past hybridisation events. The comparison between morphological traits, previously suggested as diagnostic for species identification, and genetic identification, enabled validation of the most reliable and practical morphological traits for
species identification. The shape of the dermal denticles represents the most reliable trait, but its use during fieldwork may be impractical. The black spots on body sides were present almost exclusively in M. punctulatus, allowing its identification; however, their absence is not diagnostic for M. mustelus. The distance
of the nostrils and the shape of the mouth are useful to distinguish the two species during fieldwork. Our results will allow an accurate identification of the two species leading to the collection of reliable data on their distribution, life history traits, exploitation and status of conservation
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
Performance of sorting grids on catching elasmobranchs in a multispecies Mediterranean bottom trawl fishery
No full textElasmobranchs are among the most threatened long-lived marine species in the Mediterranean Sea. Incidental catch and intense fishing effort are considered the major threats to their conservation. To date, no Mediterranean countries has adopted specific technical measures within current conservation plans to mitigate potential impacts on vulnerable elasmobranchs. This study aimed to evaluate the effectiveness of new elasmobranch bycatch reducing devices (BRD) in a Mediterranean multispecies bottom trawl fishery (northern central Adriatic Sea, one of the most exploited basins in the Mediterranean). Specifically, two types of grids were tested: a novel shark excluder device (SED) and a flexible grid (Flexgrid). Effectiveness was evaluated in terms of bycatch and commercial catch reduction, relying on the different sizes of elasmobranchs and the main commercial species. Results showed that preliminary tests with SED were effective in excluding elasmobranch species. Catches made with this grid showed no significant difference for targeted crustacean (mantis shrimp, Squilla mantis), however, commercial losses were shown for some large bony fish. Flexgrid did not affect the catches of the main target species, such as the red mullet (Mullus barbatus), European hake (Merluccius merluccius) and mantis shrimp, but also retained small-spotted catshark (Scyliorhinus canicula). The effectiveness of the grids apparently was affected by the small size of the elasmobranchs captured. The study showed that SED and Flexgrid are valuable solutions for elasmobranchs if combined with other conservation measures (e.g. seasonal fishing closure in critical areas and good practices). Finally, strong cooperation between fishers, scientists, and managers is critical to identify the best management options in a regulatory framework where only a few elasmobranch species are formally protected. Interestingly, the study also yielded the identification of two potential aggregation-nursery areas for the small-spotted catshark (Scyliorhinus canicula) and the common smooth-hound (Mustelus mustelus)
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
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