1,720,969 research outputs found
Quale approccio metodologico adottare per la valutazione dello status di minaccia di una popolazione periferica isolata? Il caso di Drosera intermedia (Droseraceae) in Toscana
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Populus alba tolerates and efficiently removes caffeine and zinc excesses using an organ allocation strategy
No full textMixed inorganic and organic contaminations are one of the main challenges in phytoremediation, due to the higher complexity derived by pollutant interactions and the increase of phytotoxicity. The cultivation of fast-growing poplars for removing contaminants from water could be a low-cost and flexible choice. The main objective of this study was to evaluate the tolerance of a poplar species (Populus alba ‘Villafranca’ clone) to irrigation with water contaminated with zinc (Zn) and caffeine (CFN). Poplars were maintained in hydroponic and exposed to four different treatments (Control, CFN, Zn and Zn + CFN) over 7 days. Poplar showed a good tolerance to Zn and CFN treatments, without any symptom of phytotoxicity. However, the type of treatment affected the contaminant dynamics in the plant-water system and a pollutant partitioning was observed among organs, with a higher accumulation of Zn in root (472 ± 128.7 mg kg− 1 DW) and CFN in shoot (30 ± 4.5 μg g− 1 FW). Under mixed condition, the CFN uptake significantly increased in root (+ 40%) and stem (+ 28%) while the Zn concentration decreased in leaves (-19%). A focus on the potential role of natural resistance-associated macrophage proteins (NRAMPs) in divalent metal transport has been performed. A down-regulation of NRAMP1.3 was detected in roots of plants exposed to CFN treatment in relation to an increase of Mn concentration. Data confirmed the suitability of Populus alba for the remediation of multi contaminated water
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
Phytosociological approach to implement a Sedum-dominated plant community in extensive Mediterranean green roofs in different N enriched substrates
No full textExtensive green roofs (EGRs) provide some important ecosystem services including the increase of urban biodiversity. Besides Sedum, the most used genus, the establishment of plant species with different functionality increases the habitats. A survey of spontaneous plant communities, adapted to drought and low nutrients, can be a valid tool of enrichment for this urban green feature. In 2014, we carried out an experiment on a roof, setting up 12 plots of 10 cm depth filled with three different substrates composed of compost, pelletised paper sludge, and tephra (Vulcaflor), as follows: VC (Vulcaflor + compost), VPC (Vulcaflor + pellet + compost) and VP (Vulcaflor + pellet). Annual and perennial forbs, annual and perennial legumes, geophytes, CAM and grasses were planted and seeded in the boxes. After five years, the plant community was dominated by CAM (Sedum) and geophytes, and then, to increase the biodiversity, we carried out a seeding of species, mainly belonging to the phytosociological classes Stellarietea mediae and Koelerio-Corynephoretea. We monitored the total canopy cover, plant diversity (Shannon, Evenness and Simpson indices) and the percentage of plant functional types from October 2019 to June 2020. The different nitrogen contents (VC>VPC>VP) affected the spread of CAM in VPC and VP, allowing the annual seeded species to colonise. The plant diversity increased especially in VP substrate. Phytosociological approach resulted suitable to select plant species able to establish in extreme climate conditions, as well as to coexist with CAM species, increasing the diversity in poor nutrient substrate
Removal of multi-contaminants from water by association of poplar and Brassica plants in a short-term growth chamber experiment
No full textThe plant association of Populus alba L. ‘Villafranca’, Brassica oleracea var. acephala sebellica (kale), and B. oleracea var. capitata ‘sonsma’ (cabbage) was exposed to Zn, Cd, and exogenous caffeine (13CFN)-contaminated water under growth chamber conditions. In the short term of treatment (15 days), poplar increased the root dry biomass (+ 25%) and decreased the chlorophyll content in new leaves (− 32%), compared to control. On the contrary, cabbage decreased the root dry biomass, enhancing the shoot dry biomass (+ 50%). Heavy metals were mainly concentrated in plant roots and in poplar reached the highest concentrations of 705 ± 232.6 and 338 ± 85.5 μg g−1 DW for Zn and Cd, respectively. The ability of poplar to accumulate more Zn and Cd than kale and cabbage in plant biomass was confirmed by heavy metal contents, following the order: poplar > kale = cabbage. However, poplar and Brassica sp. association was very useful for Zn and Cd decontaminations as reported by the bioconcentration factors (> 1). The concentration of 13CFN was below 2.4 ng g−1 FW in poplar and 7.4 ng g−1 FW in Brassica species, suggesting the caffeine uptake and degradation by plant association. Under our experimental conditions, the removal efficiency of the system was upper to 79%, indicating the capability of Populus-Brassica association to efficiently remove Zn, Cd, and 13CFN from mixed inorganic-organic–contaminated water in short term
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
Bibliografia generale sulla lettura (per la Ricerca PRIN)
No full textSi tratta di una Bibliografia sistematica sulla lettura/scrittura frutto del lavoro dell'Unità di ricerca di Tor Vergata di un Progetto PRIN (2007). Essa è aticolata in sei sezioni: a) Per una storia della lettura/scrittura; b) Sul rapporto fra scrittura e corpo (...) le neuroscienze; c) Informatizzazione del testo; d) Critica letteraria, Sociologia, Biblioteconomia; e) Copyright e storia del diritto d'autore. La versione offerta alla lettura è la n. 9, ma si prevede che in futuro la Bibliografia possa essere incrementata e aggiornata, anche per l'auspicato apporto della comunità scientifica dei lettori
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