1,720,967 research outputs found
Valutazione della capacità di arbusti ornamentali sempreverdi di assorbire e immobilizzare i metalli pesanti nei tessuti
No full textLe zone limitrofe a vie di comunicazione caratterizzate da intenso traffico veicolare, ed in particolare quelle in ambito urbano, sono spesso caratterizzate da terreno con un’elevata concentrazione in metalli pesanti. Gli arbusti ornamentali, sebbene non abbiano masse fogliari paragonabili a quelle delle specie arboree, essendo usabili nelle aree di ridotta superficie ed avendo meno limitazioni legate all’ingombro e alla sicurezza, possono rappresentare un’efficiente soluzione per sequestrare gli inquinanti e ridurre la frazione disperdibile nell’ambiente per percolazione, soprattutto se si tratta di specie a foglia persistente.
La prova ha avuto come scopo quello di quantificare la capacità di assorbire e accumulare a livello epigeo Al, Cd, Cu, Ni, Pb and Zn di Arbutus unedo, Eleagnus × ebbingei, Ilex aquifolium ‘Nelly Stevens’, Laurus nobilis, Ligustrum japonicum, Photinia × fraseri ‘Red Robin’, Pittosporum tobira, Viburnum tinus e Viburnum tinus var. lucidum e di verificare gli effetti a livello morfologico, di un substrato proveniente da aree urbane inquinate.
Le piante, ad un anno dal taleggio, sono state coltivate su due substrati costituiti per il 20% da torba di sfagno e per il restante 80% da terra di campo (controllo) o da un mix costituito da terreno prelevato in prossimità di una linea di drenaggio del manto stradale e da un’area ex- stazione di servizio (inquinato).
Il substrato inquinato non ha indotto fisiopatie in nessuna specie e, dopo un anno di coltivazione, ha comportato l’ottenimento di piante con dimensioni della chioma e peso secco totale analoghi a quelli delle piante di controllo. In Photinia e Pittosporum ha addirittura determinato un incremento del superficie fogliare (+47.9 and +78.6%) e in Photinia e Ligustrum un aumento del peso secco delle radici, rispettivamente del 55.5 e 33.6%.
Il contenuto in metalli pesanti nei diversi organi, determinato mediante ICP-MS, ha messo in rilievo la diversa attitudine delle specie ad assorbire e traslocare gli elementi. In particolare, la maggiore attitudine ad accumulare nella chioma Al è stata riscontrata per Pittosporum e Ligustrum, per Cu in Eleagnus e Ilex, per Ni in Eleagnus, Pittosporum e Ligustrum, per Pb in Ligustrum e Pittosporum e per Zn in Eleagnus, Pittosporum e Viburnum tinus var. lucidum. Determinate, ai fini di un elevato accumulo è il tasso di crescita delle piante e il quantitativo di sostanza secca prodotta giornalmente
Il verde urbano e il suo ruolo nel sequestro dell’anidride carbonica
No full textComparazione di diverse specie arbustive sempreverdi per valutarne la capacità di assimilare e stoccare carbonio atmosferico in condizioni di disponibilità idrica ottimale o di stress idrico
Utilizzo di piante agrarie nel fitorisanamento di suoli contaminati da metalli pesdanti e metalloidi : (II) primi risultati della sperimentazione in situ di Torviscosa (Udine)
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
Valutazione della compromissione biologica di un suolo contenente ceneri di pirite in un progetto di fitorisanamento
No full textBiological health assessment of a pyrite cinder containing soil in a phytoremediation project
The applicability of phytoremediation to an industrial area where pyrite cinders from a sulphuric acid production process had been discharged for a long time was investigated . Physical and chemical analysis of pyrite cinders pointed out high levels of Cu and As together with a texture mainly based on silt and fine sand and a deficiency in plant nutrients.
Plant growth limiting factors have been identified by means of physical, chemical and biological analysis carried on a mixture (1:1, w/w) of the cinders and the soil covering cinders in the polluted site Plant bioassays (watercress germination, barley root elongation, lettuce dry biomass yield) indicated, together with the high potential toxicity of cinders, a low actual toxicity, and the effectiveness of mixing them with a topsoil covering the polluted area in order to reduce phytotoxicity. Moreover, bioassays showed that manure and compost were able to improve the poor agronomic quality of the mixture.
Arsenic and copper in soils can affect soil microbial function and community composition and, therefore, may have effects on soil ecosystem functioning. The microbial properties of the mixture have been investigated by analysing through a polyphasic approach the bacterial community structure and by evaluating its microbial function thorough the Community Level Physiological Profile (CLPP). The number of total and metal tolerant heterotrophs and actinomycetes was determined by the viable plate count method; species diversity of total bacterial community and of culturable fraction was investigated (DGGE). The number of culturable bacteria as well as the biodiversity degree was found to be comparable with that of different heavy metal polluted soils. CLPP showed the capability of the microbial community of degrading various sugars, amino acids and carboxylic acids but few aromatic compounds provided. The most of isolates identified by sequencing 16SrRNA gene and belonging to different genera were metal resistant
Qualitative and quantitative composition of the bacterial community, its catabolic versatility together with soil positive response to amendments suggest a potential success in bioremediation technologies
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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