1,720,979 research outputs found
Using SPMDs to monitor the seawater concentrations of PAHs and PCBs in marine protected areas (Western Mediterranean).
No full textAqueous concentrations of individual polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were determined in coastal sites of two marine protected areas (MPAs), that is, Asinara and the La Maddalena Archipelago, in Sardinia (Western Mediterranean Sea). The use of semi-permeable membrane devices (SPMDs) enabled the detection of dissolved PAHs and PCBs, even in very low concentrations of (pgL-1), in seawater. The results reveal significant differences between the two sampling areas relative to the concentration of the individual PAHs, which provide information concerning the pollution sources affecting relatively pristine environments. The PCBs were generally observed at levels below the detection limits of the utilised method
Passive sampling monitoring of trace metals and organics in seawater in the area of the Costa Concordia disaster (Isola del Giglio, Italy).
No full textThis work presents the results of two years monitoring of organics and trace metals
in seawater with passive sampling techniques in the area around the wreck of the
Costa Concordia cruise ship, which sank off the Mediterranean island of Giglio
(Italy) on January 2012. The aim was to monitor bioavailable contaminants released
by the wreck and/or produced by the removal yard (Parbuckling project). Sampling
was carried out at three sites from May 2012 to September 2014, one month after
the removal of the wreck. Two sites were fixed in the vicinity of wreck, at the bow
and at the aft of the ship; the third one was located in an unexposed beach of the
island. Nine sampling campaigns were carried out. In each station a canister
containing semipermeable membrane devices (SPMDs) and polar organic chemical
integrative samplers (POCIS) was deployed at 10 m. depth, fixed at a buoy by scuba
divers. Furthermore, at each canister, 9 diffusive gradients in thin films (DGTs)
devices were attached. DGTs with three different resins have been used:
Chelex-100 for Cd, Cr, Cu, Ni, and Pb; Fe-oxide for V; Spheron-thiol for Hg.
Deployment time for all samplers ranged from 5 to 7 weeks. Repeatability was
checked by the exposure of triplicate samplers. SPMDs and POCIS were extracted
and analyzed for target compounds by GC/MS. Trace metals accumulated by DGTs
were analyzed after elution by GFAAS. Mercury was determined with a direct
mercury analyzer. SPMDs allowed the determination of dissolved PAHs, NPD,
PCBs, OCPs, and PBDEs. POCIS were used to measure endocrine disruptors, such
as alkylphenols, alkylphenol ethoxylates (APEs), and steroids. The results show
higher concentrations of PAHs in the station near the bow of the ship, all along the
monitoring period. A significant correlation with V measured by DGTs was pointed
out, indicating a contamination by oil, more likely as a result of the yard activities.
This work is part of a larger monitoring plan financially supported by the Italian
Civil Protection
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
Preliminary data on benthic foraminiferal assemblages and sedimentological characterisation from some polluted and unpolluted coastal areas of Sardinia (Italy)
No full textThe relationship between living benthic foraminiferal faunas and the grain-size distribution of surface sediments was studied in three Sardinian coastal areas: a) the shallow inner shelf between Portoscuso and S. Pietro and the S. Antioco islands; b) the Porto Torres harbour; and c) the La Maddalena Archipelago. This investigation forms part of the research project "EU MOMAR". Benthic foraminifera were identified in 17 samples collected from the three analysed areas. Biotic parameters (Species' Richness, Foraminiferal Density and the Fisher-α index) were calculated to quantify the foraminiferal assemblages within the context of environmental parameters. Grain-size analyses were performed to verify the granulometric nature of the bottom sediments. On the basis of the data obtained, the spatial distribution of the foraminiferal assemblages has allowed highly to less stressed environments to be distinguished and the ecological quality status to be evaluated. The most abundant taxa are Quinqueloculina ungeriana d'Orbigny, 1846, Peneroplis pertusus (Forskal, 1775) and Ammonia tepida (Cushman, 1926) from the Portoscuso samples, P. pertusus, Quinqueloculina seminula (Linnaeus, 1758) and Q. laevigata d'Orbigny, 1839 from the Porto Torres samples and P. pertusus, Bolivina spathulata (Williamson, 1858) and Bolivina striatula Cushman, 1922 from the La Maddalena samples. Among these dominant species, Ammonia tepida and bolivinids appear to show tolerance to environmental disturbance and are therefore particularly suitable as bio-indicators in coastal areas. The sampling sites characterised by better environmental conditions present an epiphytic biocoenosis with Lobatula lobatula (Walker & Jacob, 1798), Planorbulina mediterranensis d'Orbigny, 1826, Elphidium crispum (Linnaeus, 1758) and peneroplids. Correlations are still ongoing between sedimentological features, benthic foraminiferal assemblages and chemical data from these sampled areas, with a view to understanding the environmental anthropogenic impact on coastal systems
Exploring the bacterial gut microbiota of supralittoral talitrid amphipods
No full textTalitrid amphipods (sandhoppers and beach fleas) are typical of the supralittoral zone. They are known to thrive on stranded materials, including detrital marine angiosperms and macroalgae, as well as occasional dead animals. In this work, the gut microbiota of five species of talitrid amphipods (Talitrus saltator, Talorchestia ugolinii, Sardorchestia pelecaniformis, Orchestia montagui and Orchestia stephenseni) collected in Sardinia (Italy) has been investigated through: i) metabarcoding analysis of the amplified 16S rRNA V4 region; and ii) quantification of family 48 glycosyl hydrolase genes (GHF48), involved in cellulose degradation. Results indicate that, though talitrid gut biodiversity is not directly related to taxon or sampling locality, the animals' digestive tracts may host species-specific bacterial communities. In particular, gut microbiota of O. montagui, an inhabitant of Posidonia banquettes and macro-algae mat, showed the greatest differences in taxonomic composition and the highest proportion of GHF48 genes with respect to 16S rRNA genes. These results suggest that the different talitrid species may host species-specific bacterial communities whose function could partially reflect the different microhabitats and food preferences of their host
Monitoring of trace metals in coastal sediments from sites around Sardinia, Western Mediterranean
No full textIn this study the authors explore, for the first time, monitoring data on trace metals (Al, As, Cd, Cr, Cu, Fe, Hg, Pb, and Zn) collected from coastal superficial sediments of Sardinia (Italy). Eight sampling sites representative of areas at different levels of exposure to contaminants were selected. Sediments were collected twice a year, in April and September, from 2001 to 2006. The results provided a dataset of trace metal concentrations in this region of the Western Mediterranean based on a prolonged period
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