1,720,972 research outputs found
Zn, Pb and Hg contents of Pistacia lentiscus L. grown on heavy metal-rich soils: implications for phytostabilization
No full textIn this study, we determined the metal (Zn, Pb and Hg) contents in epigean and hypogean organs of Pistacia lentiscus L., a Mediterranean native plant grown on heavy metal-rich soils of Iglesiente (southwestern Sardinia, Italy), in view of its perspective use for revegetation and phytostabilization of mine waste piles. Plant samples were collected from four different areas in the district. Metal contents in the different plant tissues are roughly dependent on their total and mobile (diethylene triamine penta acetic acid (DTPA)-extractable) contents in soil and are shown in the following ranges: 48–628 mg kg−1 (Zn), 2–354 mg kg−1 (Pb) and 13–530 μg kg−1 (Hg) and usually decrease in the following order: roots>stems>leaves; the apparent exception for Hg, with an order of leaves>stems, is ascribed to foliar absorption of this element. The biological concentration factors are consistently low (≤0.05) for all metals and support the concept that the strategy of metal tolerance of P. lentiscus is based on exclusion. These results are consistent with most previous literature data, confirming that P. lentiscus is well suited for revegetation actions and could decrease metal mobility through the soil stabilization strategy
Phytoremediation potentiality of Cistus Ssp. and Inula Viscosa in heavy metal contaminated soils
No full textAim of the study is the evaluation of native Mediterranean plants, e.g. Cistus ssp and Inula viscosa, to be used for the phytoremediation of dismissed mining areas on Elba Island. The study was focused on the area named Puppaio in the Mining Park near Rio Marina. Different parameters were considered: a) heavy metal composition of the soil; b) collection and sampling of Inula viscosa (L.) Aiton, C. monspeliensis L.and C. salvifolius L. growing on contaminated soil; c) chemical analysis of different plant organs (roots, stems, leaves) in order to evaluate metal uptake and translocation; d) activity of the main antioxidant enzymes and presence of secondary metabolites linked to oxidative stress; e) in vitro cultures of the selected species, grown on specific media mimicking some of the original conditions (presence of heavy metals, extremely acidic pH), in order to obtain a population of plantlets able to be possibly reintroduced in the considered polluted areas. Preliminary results showed: a) the ability of collected plants to take up and translocate metals to the aerial parts, b) an enhanced ability of the native plants to grow in media at low pH and high metal concentration
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
Effects of exogenous cytokinins on Ni accumulation and transpiration rate of hyperacccumulator Alyssum murale grown in a serpentine soil
No full textPoster n° 2
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
Assisted phytoremediation of a multi-contaminated soil: Investigation on arsenic and lead combined mobilization and removal
No full textThe removal of contaminants from an earthy matrix by phytoremediation requires the selection of appropriate plant species and a suitable strategy to be effective. In order to set up an assisted phytoremediation intervention related to a disused industrial site affected by an arsenic and lead complex contamination, an extensive experimental investigation on micro and mesocosm scale has been conducted. Particular attention was given to the choice of plant species: using crop plants (Lupinus albus, Helianthus annuus and Brassica juncea) a series of parallel test campaigns have been realized to investigate different scenarios for the reclamation. With regard to the arsenic contamination, which is certainly the most worrying, the possibility of employing a hyper-accumulator species (Pteris vittata) has also been investigated, highlighting advantages and difficulties associated with such an approach. The application of various mobilizing agents in different concentrations was tested, in order to maximize the extraction efficiency of plants in respect of both contaminants, showing the necessity of a chemically assisted approach to promote their uptake and translocation in the shoots. Phosphate addition appears to produce the desired results, positively affecting As phyto-extraction for both hyper-accumulator and crop plants, while minimizing its toxic effects at the investigated concentrations. With regard to Pb, although tests with EDDS have been encouraging, EDTA should be preferred at present due to lower uncertainties about its effectiveness. The performed tests also improved the addition of mobilizing agents, allowing the simultaneous removal of the two metals despite their great diversity (which in general discourages such approach), with significant saving of time and an obvious improvement of the overall process
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
Earthworms as useful bioindicators of agroecosystem sustainability in orchards and vineyards with different inputs
No full textEffects of conventional and alternative management systems on soil phosphorus content, soil structure and corn yield
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