1,721,111 research outputs found
Multidisciplinary approach to validate compost use in vegetable crop systems of Campania Region (Italy): influence of compost rates on soil biological activity and heavy metal content
No full textLong-term dynamics of soil metal concentrations at the urban area of Naples (Southern Italy)
No full textMetals constitute a risk to human and environment health. Metals in urban soils derive from natural and anthropogenic sources, and their concentrations may differ over time depending on quantity and quality of emission sources. The aim of the work was to evaluate, over a period of 15 years from 1993 to 2008, differences in metal (Cr, Cu, Fe, Mn, Ni, Pb and Zn) concentrations in soils collected at the urban area of Naples (Southern Italy). Other goal was to individuate the origin (natural and anthropogenic) of the detected metals in the soils and for this aim, three indices were calculated: contamination factor, ecological risk factor, and geo-accumulation index. The results highlighted an overall decrease of metal concentrations from the beginning to the end of the study period, even if Pb concentrations in 2008 were still 2-fold higher than the threshold value fixed by the Italian law. Cr, Cu, Pb and Zn in the soils mainly derive from anthropogenic activity, as highlighted by the comparison with the baseline values. The indices suggest a moderate contamination degree but a low potential ecological risk of the investigated soils
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
Degradazione di IPA in suoli forestali: contributo della comunità microbica
No full textGli idrocarburi policiclici aromatici (IPA) sono contaminanti organici con azione mutagena e cancerogena, pertanto rappresentano un rischio per l’uomo e per gli ecosistemi. Sebbene gli IPA nel suolo possano causare tossicità verso i microrganismi edafici, la comunità microbica è in grado di degradare questi composti attraverso enzimi ad attività ossidoreduttasica. Principalmente coinvolti in questo processo sono i funghi. Scopo della ricerca è stato quello di studiare la degradazione di IPA in diversi suoli forestali: faggeta, pineta e lecceta. I suoli sono stati contaminati con fenantrene, pirene e benzo[a]pirene e incubati in mesocosmi in condizioni controllate per 108 giorni. Sono state monitorate
le concentrazioni degli IPA, le attività enzimatiche coinvolte nel processo di degradazione (laccasica e perossidasica totale) e la biomassa fungina (contenuto di ergosterolo). Al termine dell’incubazione, fenantrene e pirene hanno mostrato una forte diminuzione in tutti i suoli forestali, diversamente dal benzo[a]pirene. In seguito all'aggiunta di IPA si è osservato un decremento delle attività enzimatiche, ad eccezione dell'attività perossidasica nella faggeta, che è stata invece stimolata. Le concentrazioni di ergosterolo sono risultate più alte dopo l’aggiunta di IPA nella faggeta e nella lecceta, mentre sono diminuite nella pineta, sebbene questo sistema mostri sempre i valori più alti
Assessment of nutritional status and trace element contamination of holm oak woodlands through analyses of leaves and surrounding soils.
No full textAcute effects of PAH contamination on microbial community of different forest soils
Full text linkPolycyclic aromatic hydrocarbons (PAHs) are hazardous organic compounds with mutagenic, genotoxic and carcinogenic properties. Although PAHs in soil can cause toxicity to microorganisms, the microbial community is able to degrade these compounds. For this reason, it is important to study acute and short-term effects of PAH contamination on soil microbial community, also to shed light on its possible exploitation in soil restoration.
The effects of acute PAH contamination on the structure and metabolic activity of microbial communities in three forest (beech, holm oak, black pine) soils were studied. The soils were spiked with phenanthrene, pyrene or benzo[a]pyrene and incubated in experimental mesocosms, under controlled conditions. Enzymatic activities (laccase, total peroxidase and hydrolase), as well as microbial biomass and community structure (through phospholipid fatty acid and ergosterol analyses), were evaluated in the three soil systems 4 days after contamination and compared to no-spiked soils. In soil under holm oak, there was a stimulation of Gramþ bacteria after contamination with all the 3 PAHs, whereas in soil under pine, pyrene and phenanthrene additions mainly stimulated fungi and actinomycetes
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