1,720,973 research outputs found
Bioaccumulation of endocrine disrupting compounds in the Greenland shark Somniosus microcephalus from the Greenland seawaters.
No full textRecent climate changes associated with anthropogenic emissions of pollutants are triggering shifts in global biogeochemical cycles and polar marine ecosystem. The decrease of sea ice and the mechanism of ice formation/melting, may considerably have an impact on the mobility of contaminants and on the loss of biodiversity. In this work, we report the occurrence and bioaccumulation of selected endocrine-disrupting compounds (EDCs) in muscle and liver of the Greenland shark Somniosus microcephalus, an arctic species of interest for biogeography, migration, physiology, long- and short-term contaminant storage. The EDCs selected for this study were 4-nonylphenol (4-NP), its mono- (NP1EO) and di-ethoxylate (NP2EO) precursors and bisphenol A (BPA). There are currently very few scientific papers on the distribution and transport of these EDCs in the arctic marine food web and no such studies have been performed on the Greenland shark. Totally, muscles and liver samples were analyzed from 23 Greenland sharks (TL range 149–442 cm) sampled in W, SW, SE, and NE Greenland. Extraction of analytes from biological matrices were performed by ASE (Accelerated Solvent Extraction), followed by HPLC-Fluorescence (FLD) detection. Results showed higher contamination levels in muscle than in liver in the sharks from SE and NE Greenland, while in specimens from W and SW Greenland the liver was the tissue more contaminated. In fact, the 4-NP, NP1-2EO and BPA mean content in liver of SW Greenland specimens was 43.5 ng/g, 288.5 ng/g and 8.2 ng/g wet wt respectively, while in muscle mean concentrations was 20.3 ng/g for 4-NP, 171.1 ng/g wet wt for NP1-2EO and 7.9 ng/g for BPA. Results confirm the presence of selected EDCs in this species, suggesting the transfer of contamination in the Euro-Arctic marine trophic web
Bioaccumulation of nonylphenols and bisphenol A in the Greenland shark Somniosus microcephalus from the Greenland seawaters
No full textRecent climate changes associated with anthropogenic emissions of pollutants are triggering shifts in global biogeochemical cycles and polar marine ecosystem. The decrease of sea ice and the mechanism of ice formation/melting, may considerably have an impact on the mobility of contaminants and on the loss of biodiversity. In this work, we report the occurrence and bioaccumulation of selected endocrine-disrupting compounds (EDCs) in muscle and liver of the Greenland shark . Somniosus microcephalus, an arctic species of interest for biogeography, migration, physiology, long- and short-term contaminant storage. The EDCs selected for this study were 4-nonylphenol (4-NP), its mono- (NP1EO) and di-ethoxylate (NP2EO) precursors and bisphenol A (BPA). There are currently very few scientific papers on the distribution and transport of these EDC. s in the arctic marine food web and no such studies have been performed on the Greenland shark. Totally, muscles and liver samples were analyzed from 23 Greenland sharks (TL range 149-442. cm) sampled in W, SW, SE, and NE Greenland. Extraction of analytes from biological matrices were performed by ASE (Accelerated Solvent Extraction), followed by HPLC-Fluorescence (FLD) detection. Results showed higher contamination levels in muscle than in liver in the sharks from SE and NE Greenland, while in specimens from W and SW Greenland the liver was the tissue more contaminated. In fact, the 4-NP, NP1-2EO and BPA mean content in liver of SW Greenland specimens was 43.5. ng/g, 288.5. ng/g and 8.2. ng/g wet wt respectively, while in muscle mean concentrations was 20.3. ng/g for 4-NP, 171.1. ng/g wet wt for NP1-2EO and 7.9. ng/g for BPA. Results confirm the presence of selected EDCs in this species, suggesting the transfer of contamination in the Euro-Arctic marine trophic web
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
Germination, root elongation, and photosynthetic performance of plants exposed to sodium lauryl ether sulfate (SLES): an emerging contaminant
No full textThe anionic surfactant SLES (sodium lauryl ether sulfate) is an emerging contaminant, being the main component of foaming agents that are increasingly used by the tunnel construction industry. To fill the gap of knowledge about the potential SLES toxicity on plants, acute and chronic effects were assessed under controlled conditions. The acute ecotoxicological test was performed on Lepidum sativum L. (cress) and Zea mays L. (maize). Germination of both species was not affected by SLES in soil, even at concentrations (1200 mg kg−1) more than twice higher than the maximum realistic values found in contaminated debris, thus confirming the low acute SLES toxicity on terrestrial plants. The root elongation of the more sensitive species (cress) was instead reduced at the highest SLES concentration. In the chronic phytotoxicity experiment, photosynthesis of maize was downregulated, and the photosynthetic performance (PITOT) significantly reduced already under realistic exposures (360 mg kg−1), owing to the SLES ability to interfere with water and/or nutrients uptake by roots. However, such reduction was transient, likely due to the rapid biodegradation of the surfactant by the soil microbial community. Indeed, SLES amount decreased in soil more than 90% of the initial concentration in only 11 days. A significant reduction of the maximum photosynthetic capacity (Pnmax) was still evident at the end of the experiment, suggesting the persistence of negative SLES effects on plant growth and productivity. Overall results, although confirming the low phytotoxicity and high biodegradability of SLES in natural soils, highlight the importance of considering both acute and nonlethal stress effects to evaluate the environmental compatibility of soil containing SLES residues
Multiple exposure of the Boreogadus saida populations to legacy and emerging pollutants from inner and outer Bessel fjord (NE Greenland)
No full textTemporal trend of perfluoroalkyl substances and current-use pesticides in penguin eggs from the Ross Sea (Antarctica)
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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