1,720,962 research outputs found
Bioaccumulation of heavy elements by Armadillidium vulgare (Crustacea, Isopoda) exposed to fallout of a municipal solid waste landfill.
No full textThis paper reports the response of isopods exposed to fallout of a municipal solid waste landfill located in
central Italy. Soil samples and specimens of Armadillidium vulgare were collected at different distances
from the landfill and analyzed to determine the concentrations of heavy elements such as As, Cd, Co, Cr,
Cu, Ni, Pb, Sb, V and Zn. The isopod analysis was performed on unpurged and purged specimens.
Analytical data indicate that the soil contents of heavy elements were quite uniform and within the
respective local geochemical background. Slight enrichments of Cu and Pb were found in some soils
collected within the solid waste. Purged isopods showed an accumulation of As, Co, Cr, Ni, Sb and V whose
body levels decreased as the distance from the landfill increased. Cd, Cu, Pb and Zn concentrations in
purged specimens were rather uniform and no significant variation trend occurred. This result probably
was due to the fact that the isopods are provided with physiological mechanisms of regulation for these
heavy elements. Analytical data also indicate the ability of A. vulgare to adsorb differently the heavy
elements according to the following order: As > Co > Ni > Pb > V. The contents of heavy elements in
unpurged specimens were higher than in purged ones. This finding suggested that the defecation has
marked effects on the tissue levels of heavy elements in isopods. This study indicates that the isopods
provide useful information about environmental quality in areas characterized by low and discontinuous
emission of heavy elements and their low accumulation in soil
Integrated approach for the analysis of ecosystems at risk: a case study in a waste landfill.
No full textMulti-matrix environmental monitoring to assess heavy element distribution around a municipal solid waste landfill in Italy
Full text linkMulti-matrix environmental monitoring was used to evaluate the influence of a municipal solid waste landfill (Ginestreto, Emilia Romagna, Italy) on the level and distribution of heavy elements in the surrounding environment (air, soil and soil biota). Concentrations of As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, Tl and Zn were measured by inductively coupled plasma-mass spectrometry in transplanted lichens, topsoils and isopods. The highest accumulation levels found for Cd, Cr, Pb, Sb and Zn in lichens transplanted within the Ginestreto landfill. However, similar concentrations of these heavy elements were also found in lichens exposed in monitoring sites influenced by other man-made sources, such as vehicle traffic and truck movements. The fallout of heavy elements emitted by the landfill had low impact on their levels in topsoil: Cd, Cr, Pb, Sb and Zn showed higher contents in topsoil collected close to the landfill and a slight decrease in concentrations with increasing distance from the landfill. There was no variation in heavy element accumulation in isopods in relation to distance from the landfill. The results of this study indicate that the Ginestreto municipal solid waste landfill had limited impact on the environmental distribution of heavy elements, since accumulation and enrichment in lichens and topsoils were only detected close to the landfill, up to about 100 m from its border
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
EPR study of the adsorption of dioxin vapours onto microporous carbons and mesoporous silica
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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