1,720,962 research outputs found
Reconstructing the history of the sand tiger shark (Carcharias taurus) in the Mediterranean Sea
No full textSharks are globally exposed to several anthropogenic threats, which, in many cases, have severely reduced their distribution and have impacted populations. In the Mediterranean Sea, because of its long history of exploitation and the relatively short span of scientific monitoring, reconstructing shark baselines is challenging. Many vulnerable species declined in population abundance and geographic distribution before it was possible to adequately track these changes. Consequently, for many of these species, current conservation assessments are now suffering from a severe case of shifting baseline syndrome, whereby their historical occurrence in the area is questioned.The sand tiger shark (Carcharias taurus) is one of these cases. Characterized by high philopatry, restricted home range, and low interchange between populations, its Mediterranean population may have been severely impacted by the high historical fishing pressure in the region before scientific monitoring began.In this study, the history of the abundance and distribution of C. taurus in the Mediterranean Sea was reconstructed through a comprehensive search of occurrence records in the literature and in museum collections. Between 1810 and 2008, 31 occurrence records and 54 publications provided information on the presence of the species in the area. These records were sparse but systematic over time and indicated occurrence hot spots in the south-western Mediterranean Sea and in the eastern Adriatic Sea.The presence of ten sightings of juveniles from a total of 18 sightings with length information suggested local parturition. Habitat and extinction models indicate that the area has suitable oceanographic conditions for the occurrence of the species and that the species cannot be considered extinct in the Mediterranean Sea. Our study suggests that there is still hope for the recovery of the species and underlines the crucial role of historical investigations to reconstruct the history of large elasmobranchs in the Mediterranean Sea
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
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
Infezioni di origine batterica in elasmobranchi in un acquario espositivo
No full textGli elasmobranchi rappresentano attrazioni popolari negli acquari pubblici e negli zoo sin dal 1860.
Nel corso degli ultimi anni le conoscenze relative alla biologia e alla gestione degli elasmobranchi
in ambiente controllato sono aumentate e diverse sono le specie mantenute e riprodotte con
successo. Al contrario, informazioni relative alle patologie sono limitate e sono riferite
principalmente a deformità spinali, patologie tiroidee, neoplasie e malattie di origine parassitaria ed
infettiva. Fra queste le infezioni di origine batterica soprattutto sostenute da microrganismi
appartenenti alla famiglia delle Vibrionaceae rivestono un ruolo importante in quanto spesso
correlate ad episodi di mortalità. Tra le diverse specie di Vibrio il V. harveyi (sinonimo di V.
carchariae), segnalato in diverse specie come squalo toro (Carcharias taurus), squalo limone
(Negaprion brevirostris), squalo grigio (Carcharhinus plumbeus) e spinarolo (Squalus acanthias) è
spesso associato a fenomeni di meningite o ad ulcere cutanee. Altri Vibriocome V. alginolyticus,
V. parahaemolyticuse il Photobacterium damselaesubsp. damselaesono stati correlati ad episodi
di mortalità ma in sovrapposizione solitamente con altre patologie. L'Aeromonas salmonicida è
documentata come agente causale di malattia in pinna nera (Carcharhinus melanopterus) mentre
negli squali martello (Shyrna tiburo) sono stati segnalati Serratia marcescense, in giovanili con
sintomi neurologici,Flavobacterium sp.. Recentemente anche i micobatteri come Mycobacterium
aviume M. chelonaesono stati isolati da lesioni granulomatose diffuse rispettivamente in squalo
bamboo (Hemiscyllium ocellatum) e nel pesce violino (Rhinobatos lentiginosus).
Nell'acquario di Cattolica (RN) sono presenti oltre100 esemplari di elasmobranchi appartenenti a
16 specie diverse. Nel corso degli ultimi anni la maggior parte degli episodi di mortalità che si sono
verificati sono riferiti principalmente a patologiedi origine batterica prevalentemente associate alla
presenza di V. harveyi. In particolare tale patogeno è stato correlato al decesso di 4 giovani
esemplari di S. tiburo, 5 esemplari di cui 4 esemplari giovanili ed uno adulto di squalo pinna nera
(C. melanopterus), 3 esemplari giovanili di squalo bamboo (Chiloscyllium punctatum) in
concomitanza con V. fischeri ed in un esemplare di squalo nutrice adulto (Ginglymostoma
cirratum) in associazione alla presenza di P. damselae subsp. damselae. In tutti i soggetti deceduti
sono stati riscontrati quadri di meningite ed enterite e tutti gli episodi di mortalità si sono verificati
durante il periodo di quarantena o dopo il loro trasferimento in una nuova vasca.
Infine in un esemplare adulto di squalo toro (C. taurus) che mostrava estese lesioni cutanee di tipo
necrotico è stata rilevata la presenza di Tenacibaculum maritimum.
Le principali problematiche sanitarie riscontrate nell’ambiente controllato dell’acquario sono
rappresentate da infezioni batteriche sostenute da agenti patogeni opportunisti ubiquitari in
ambiente acquatico (soprattutto Vibrio) che sono in grado di causare, in presenza di condizioni
predisponenti, patologie batteriche superficiali e/o sistemiche anche gravi che possono portare
anche alla morte. Pertanto l’applicazione di attenti protocolli gestionali possono essere utili al fine
di ridurre le condizioni di stress a cui gli animali possono essere sottoposti soprattutto durante le
fasi successive al trasporto e all’acclimatamento alle nuove condizioni di vita.
Per quanto concerne T. maritimum ulteriori indagini andranno condotte al fine di stabilire il ruolo
patogeno e le modalità di trasmissione di tale microrganismo negli elasmobranchi soprattutto in
condizioni di coabitazione con teleostei
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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