1,720,962 research outputs found
Studio sulla fauna ittica e macrobentonica del fiume Neto (Cotone, Calabria): bioindicatori a confronto
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Esperienze di studio della qualità biologica di corsi d’acqua italiani mediante l’uso delle diatomee
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Temporal trends of element concentrations and ecophysiological parameters in the lichen Pseudevernia furfuracea transplanted in and around an industrial area of S Italy
No full textThis study investigated the temporal trends of element concentrations and ecophysiological parameters (integrity of cell membranes, membrane lipid peroxidation, and sample vitality) in thalli of the lichen Pseudevernia furfuracea transplanted in and around an industrial area of S Italy from May 2010 to May 2011, once every 3 months. Element accumulation at levels indicating that the atmosphere of the study area was polluted by most elements occurred only during the third trimester of exposure, and the ecophysiological parameter best reflecting this trend was sample vitality expressed in terms of activity of the enzyme dehydrogenase. Among the available climatological parameters, the different amount of rainfall during the exposure period may influence the results, especially the number of hours with rainfall >16 mm/day, which is the threshold between light-moderate and moderate-heavy rainfall in the Mediterranean area
Element concentrations in the lichen Pseudevernia furfuracea (L.) Zopf transplanted around a cement factory (S Italy)
No full textAbstract Samples of the lichen Pseudevernia furfuracea (L.) Zopf collected from an unpolluted area were transplanted for 3 months at 60 sites around a cement factory in S Italy and then analysed by ICP-MS for their Al, Ca, Fe, K, Mg, Mn, Na and V contents. These elements have the highest emission factors during cement production. Data were processed using both univariate and multivariate statistics, i.e. ANOVA, Bray–Curtis analysis and multi-response permutation procedure (MRPP). All these elements accumulated in the transplanted lichens, with Ca being the most abundant element. The Bray–Curtis analysis identified 10 groups of sites along axis 1, which accounted for 88.5% of the total variance. The \{MRPP\} results supported the results of the Bray–Curtis analysis. The groups at the two ends of axis 1 were those least affected (group 10) and most affected (group 1) by air pollutants from the cement factory. In view of the element concentrations measured in group 10, it was considered an “internal control” and then compared to the other groups to detect statistically significant differences (ANOVA). This data analysis revealed spatial trends suggesting that the cement factory contributed to the Fe, Al and V enrichment in the exposed lichens. Moreover, the sites in group 10 showed values comparable to or even lower than those of unexposed samples for all elements except vanadium, further supporting this element's role in air pollution monitoring
Licheni e bioaccumulo di levoglucosano, un tracciante di combustione di biomassa legnosa
No full textGoing 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
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