1,720,985 research outputs found
Analisi del contenuto di metalli in traccia nella frazione PM10 del particolato atmosferico della città di Palermo.
No full textNew records of two uncommon species, calappa tuerkayana pastore, 1995 (Decapoda, calappidae) and parasquilla ferrussaci (roux, 1828) (stomatopoda, parasquillidae), from the strait of sicily (central mediterranean sea)
Full text linkThe shamefaced crab Calappa tuerkayana Pastore, 1995 and the mantis shrimp Parasquilla ferussaci (Roux, 1828) are two crustacean species rarely reported in the Mediterranean Sea. In December 2018, two specimens of C. tuerkayana and one specimen of P. ferussaci were collected on a soft bottom at about 132 and 145 m depth during a trawl survey off Mazara del Vallo harbour (Strait of Sicily). This note reports the northernmost record of C. tuerkayana in the Strait of Sicily and confirms the occurrence of P. ferussaci in the same area. An update of the spatial distribution of these crustacean species in the Mediterranean Sea is also presented
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
Further records of Callinectes sapidus (Rathbun, 1896) (Decapoda, Brachyura, Portunidae) in the Strait of Sicily
Full text linkFive specimens of the invasive American blue crab Callinectes sapidus were caught from October 2018 to December 2019 off the Mazara del Vallo harbour, Strait of Sicily. This note documents further records of the species in the Strait of Sicily and its settlement in the area. In addition, an update of the spatial distribution of C. sapidus in the Mediterranean Sea was provided
Evaluation of the Economic Performance of Coastal Trawling off the Southern Coast of Sicily (Central Mediterranean Sea)
Full text linkThe economic performances of four trawling fleets (those of the Sicilian cities of Trapani, Sciacca, Licata and Porto Palo di Capo Passero) operating in the coastal waters along the southern coast of Sicily (geographical Subarea 16), and potentially affected by the establishment of the Fisheries Restricted Areas (FRAs), were analysed. The main economic performance results (revenues, costs and profits) of 37 trawlers were calculated prior to the implementation of FRAs and compared with those estimated by the spatial bio-economic model SMART after the FRAs’ establishment. Results showed that the fleets of Sciacca and Licata, located in the central part of the southern Sicilian coast, had a short-term reduction of profits as a result of the implementation of the FRAs; conversely, a short-term increase in the economic performances of Trapani and Porto Palo di Capo Passero fleets was expected. Although the FRAs represent a good tool for rebuilding overexploited stocks, the different socio-economic impacts of the single fleets should be assessed before adopting them and the implementation of specific compensative measures should be planned for the impacted fleet until a more productive state of the stock is reached
First record of Trachipterus trachypterus Gmelin 1789 (Lampriformes) in the Strait of Sicily | Prvi nalaz mača srebrenjaka Trachipterus trachypterus Gmelin 1789 (Lampriformes) u Sicillijanskom tjesnacu
No full textOn July 7th 2018 a specimen of Mediterranean dealfish (Trachipterus trachypterus Gmelin 1789)
was caught in the shallow waters of Selinunte (in the South-Western coast of Sicily) by trammel net.
It was a female in maturing phase and the gonadosomatic index resulted as 1.1%. The specimen
measured 1638 mm in total length and weighed about 2480 g. The estimated age through growth
increments in vertebra was of 41 years. The finding of the Mediterranean dealfish in the Strait of
Sicily might be linked to its spawning period during which it approaches the shallow waters. The
present specimen represents the first record in the Strait of Sicily
Assessing Cephalopods Fisheries in the Strait of Sicily by Using Poor Data Modeling
Full text linkCephalopods, including octopuses, squids, and cuttlefishes, are exploited by both bottom trawl and small-scale fisheries (SSF) in most of the Mediterranean areas. Bottom trawl fisheries regard cephalopods as a valuable bycatch, whereas for SSF, they are among the main target species. Cephalopods account for a relatively small proportion of the total landings in the Mediterranean. However, from an economic point of view, four cephalopods, Eledone cirrhosa, Eledone moschata, Octopus vulgaris, and Sepia officinalis, account for approximately 15% of the total landing value. Despite their economic importance, there are very few stock assessments of cephalopods in the Mediterranean because it is difficult to assess them by classical age-based methods, given their short life-cycles, and highly variable growth and recruitment. The production of E. cirrhosa, E. moschata, Illex coindettii, Loligo vulgaris, O. vulgaris, S. officinalis, and Todaropsis eblanae in the waters off the south of Sicily accounts for approximately 8% of the total Mediterranean yield of cephalopods. This study presents the first attempt to assess the state of these cephalopods in the Strait of Sicily by using surplus production models. Since species-wise landing statistics may be unreliable because of their morphological similarity, some octopuses (E. cirrhosa and E. moschata) and ommastrephid squids (I. coindetii and T. eblanae) were assessed combined. Landing data and abundance indices from trawl surveys were used to describe cephalopod stock dynamics through the Bayesian State Space Schaefer model (BSM) and Surplus Production model in Continuous Time (SPiCT) models. As survey data were not considered reliable indicators of their abundance, O. vulgaris, S. officinalis, and L. vulgaris stocks were assessed using the Catch-Maximum Sustainable Yield (CMSY) model. Overall, squid and cuttlefish stocks were observed to be in healthy conditions. However, assessments of octopus stocks indicated that their condition was critical or recovering. Here, we discuss the different stock statuses in the light of evolving fisheries and environmental factors in the area over time. Although cephalopods are not a priority in the current management system of Mediterranean fisheries, the importance of these species in the food web and their relevance for SSF underline their importance and their exploitation status should be periodically evaluated
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