1,721,001 research outputs found
Abundance, activity and critical habitat of the striped dolphin Stenella coeruleoalba in the Gulf of Taranto (northern Ionian Sea, central Mediterranean Sea)
Full text linkAbundance, density, daily variation in group size, activity and habitat use of the striped dolphin in the Gulf of Taranto (northern Ionian Sea, central Mediterranean Sea) were investigated using data from sightings collected between April 2009 and December 2016 during standardized vessel-based surveys. Density and abundance were estimated in the survey area by means of conventional distance sampling, resulting in 0.97 specimens/km2 (CV = 5.77%; 95% CI = 0.86–1.08 specimens/km2) and 615 specimens (CV = 5.77%; 95% CI = 549–689 specimens), respectively. Group size data were analysed using multivariate methods. The changes in group size, depth and percentage occurrence of activity between daily periods were investigated with non-parametric tests. The spatio-temporal distribution of the striped dolphin in each predominant activity was investigated by means of the ordinary Kriging method. Fifteen year-maps of spatial prediction were produced, allowing the identification of persistent areas. The results delineate a critical habitat of about 150 km2 in the northernmost ‘Taranto Valley’ canyon system ranging between 140 and 910 m in depth. This critical habitat was persistently and regularly used by an important estimated population of striped dolphins for their day-to-day survival and maintenance in a healthy condition. The intense human use occurring in the area highlights the need for local, national and EU management to set a comprehensive strategy. The establishment of a SPAMI (Specially Protected Area of Mediterranean Importance) as an effective tool for the conservation of the species is suggested. The consequence of establishing a closed area could be reasonably accepted by local concurrent stakeholders. Indeed, limiting access through the establishment of this small closed area would result in the protection of a habitat acting as an ecological refuge for many other pelagic and demersal species of commercial interest, thus favouring their spill over
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
Mega-litter and remediation: the case of Mar Piccolo of Taranto (Ionian Sea)
No full textAccording to the United Nations Environment Programme/Mediterranean Action Plan (UNEP/MAP), marine litter is one of the main causes of marine pollution in the Mediterranean Sea and one of the most important threats for its biodiversity. In addition, it is a critical issue with significant implications from an ecological point of view, as well as for human health and safety. The present study provides a focus concerning the mega-litter in a semi-enclosed basin, the Mar Piccolo of Taranto (Southern Italy, Ionian Sea). In this basin, characterized by a suite of anthropic impacts, a specific protocol for the mega-litter removal has been developed according to the Special Commissioner for remediation of the Site of National Interest of Taranto. The application of such protocol proved to be effective in limiting the removals’ secondary effects on the biodiversity and on the environment as a whole, allowing a sustainable removal of marine mega-litter. A critical part of such protocol resulted in the translocation of species of conservation interest present on the debris, particularly considering the rich population of the pen shell Pinna nobilis thriving in the area. A total of 7107 specimens were translocated, showing low mortality percentage and high survival rates during 9 months of monitoring
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
Influence of hydraulic clam dredging and seasonal environmental changes on macro-benthic communities in the Southern Adriatic (Central Mediterranean Sea)
No full textMacro-benthic communities on the shallowest soft bottoms are impacted by hydraulic dredgers used for the harvesting of the striped venus clam (Chamelea gallina). Changes in macro-benthic assemblages were analysed across four areas in the Southern Adriatic Sea (Central Mediterranean Sea) during the winter and summer 2022 (low and high fishing pressures, respectively). Two sampling surveys were carried out collecting abundance data (N/100m(2)) of 69 species. Diversity indices (Shannon-Weiner and Equitability) were calculated and differences between seasons and areas were tested using non-parametric tests. Changes in the assemblage and feeding habits were explored by adopting permutational multivariate analysis of variance on 34 species. Moreover, environmental conditions of all areas in the two seasons were characterized by a set of 8 variables. Seasonal changes in diversity were only detected for the Shannon-Weiner index, with values significantly higher in winter than summer. Macro-benthic assemblages differed between the two seasons, and the winter assemblages were well-distinct in each area. In contrast, a high overlap was shown in the summer assemblages of the four areas. Changes in feeding habits showed an increase in filter feeding polychaetes and opportunistic/scavenger species during the summer. Temperature, Salinity and primary production were positively correlated to summer stations indicating potential thermic stress on the assemblages. The results provide information on the benthic community impacted by dredge disturbance and seasonal changes driven by environmental conditions, stressing the need to integrate these aspects in assessments on the health status of marine ecosystems required by European directives and fishery management plans
Evidence of Inter-Regional Connectivity for Risso’s Dolphins in the Western Ionian Sea, Central Mediterranean Sea
No full textThis brief report is the first comparative study of a photo-identification catalogue of the
Risso’s dolphins (Grampus griseus) in the Western Ionian Sea (Central Mediterranean Sea).
The positive match of two photo-identified individuals observed in two neighbouring areas
in different and non-consecutive years represents the first record of Risso’s dolphin re-
sightings across two Ionian sub-regions. This suggests potential inter-regional connectivity
for the species, as reported in other sub-regions of the Mediterranean basin. Further, this
supports the hypothesis that Risso’s dolphins use a large home range with seasonally
different critical habitats, as suggested in previous studies carried out in the Western
Ionian Sea
Parsimonious AHP applied to the conservation of cetaceans: a case study in the Gulf of Taranto
No full textDispelling 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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