1,720,964 research outputs found
SUSPENDED MATTER PROPERTIES AND ITS ROLE IN POLLUTANT TRANSFER FROM THE RIVER TO THE SEA - CASE-STUDY - ADIGE RIVER ADRIATIC SEA
No full textSuspended matter and bottom sediments have been investigated in the Adige River estuary (Northern Adriatic Sea) and their role in the heavy metals transfer from land to sea. The observed similarity of the geochemical and mineralogical composition between the riverine suspended matter and the marine sediments just at the Adige mouth reveals that most of the riverborne suspended particles settle in the prodelta area together with the associated heavy metals. Among the various toxic elements examinated, chromium has a peculiar behaviour, which indicates the man's influence on its biogeocycle. © 1986
Geochemical considerations on trace element distributions in suspended matter and sediments at the river-sea interface, Adige River mouth, northern Adriatic sea
No full textThe particulate matter at the Adige River mouth has been investigated in order to determine the natural geochemical processes in the estuarine environment, and the anthropogenic influence on the biogeochemical cycling of heavy metals. The determination of suspended matter and sediment physico-chemical characteristics (grain size, mineralogy, organic matter content, specific surface area), and of concentrations of major and trace elements in the Adige River mouth in different hydrological conditions, has shown that this mouth acts as a trap for most heavy metals. Heavy metals were found to be preferentially bonded to the particulates, and in the estuarine mixing zone scavenging of most dissolved metals occurs, due to salinity and pH gradients, and to the formation of new particulate organic matter. The surface characteristics of suspended particulate matter [fine grain size, abundance of clay minerals, large specific surface area (SSA), organic and inorganic coatings] favour the adsorption of heavy metals. The sedimentation pattern (rapid deposition due to flocculation of fine particles, and to low environmental energy and estuarine circulation) causes accumulation of particulate matter, enriched in heavy metals, in the prodelta zone. Moderate anthropogenic influence on Cu, Pb, Cd, and Cr concentrations has been recognised in the Adige River. The environmental fate of these elements is determined by the same natural processes, and therefore accumulation in front of the river mouth occurs. The elevated partitioning in the organic phase of the anthropogenically influenced elements, could favour their mobility in different environmental conditions. © 1989
The Role of Suspended Matter in the biogeochemical cycles in the Adige River Estuary (Northern Adriatic Sea)
No full textSuspended matter and sediments from the Adige River mouth were analysed in an attempt to elucidate the transfer of heavy metals from the river to the sea. The vertical profile of grain-size spectra of suspended matter in front of the river mouth has shown that the riverine particles are limited to the upper brackish layer. Particulate matter was found to have a large specific surface area, up to 20 m2 g-1 in the estuarine sample. High quantities of quartz and phyllosilicates (micas and clay minerals) were found in the riverine suspended matter. The quartz content of the suspended matter from the brackish layer was found to be diminishing and with the organic matter becoming the essential component (22%). Higher levels of trace metals were usually detected in suspended matter samples (40 ppm Ni, 200 ppm Cr, 60 ppm Pb, 100 ppm Cu, 320 ppm Zn, and 0·9 ppm Cd) than in sediments. The observed similarity of physico-chemical, mineralogical and geochemical characteristics of riverine suspended matter and recent marine sediments, indicates that most of the riverborne particulate matter is deposited in the proximity of the Adige River mouth. The peculiar characteristics of the chromium level (high bulk concentration and its abundance in the organic fraction of the particular matter) when compared to the other trace metals, indicates the anthropogenic influence on its biogeocycle. © 1987
The tholeiitic magmatism of Jabuka, Vis and Brusnik islands: a Carnian magmatism in the Adria Plate
No full text
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
Dispelling 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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