1,721,042 research outputs found
An overview of indexes to evaluate terrestrial plants for phytoremediation purposes (Review)
No full textThis paper reviews the various factors, coefficients and indexes developed to evaluate terrestrial plant performance in respect to phytoremediation. A brief list of indexes includes the Accumulation factor, Bioabsorption coefficient, Bioaccumulation coefficient, Bioaccumulation factor, Bioconcentration, Bioconcentration coefficient, Bioconcentration factor, Biological absorption coefficient, Biological accumulation coefficient, Biological concentration factor, Biological transfer coefficient, Concentration factor, Enrichment coefficient, Enrichment factor, Extraction coefficient, Index of bioaccumulation, Mobility index, Shoot accumulation factor, Soil host transfer factor, Soil-plant transfer coefficient, Soil-plant transfer factor, Transfer factor and Translocation factor. These indexes represent the result of a ratio calculation between element concentrations in plant parts to that of substrata. In other cases indexes arise from the ratio calculation of element concentrations in two distinct plant parts. In the literature different terms have been attributed to the same ratio and this often represents an overlap in terminology. On the other hand the same term corresponds to several different ratios and this could create confusion and misinterpretation in data comparison. Furthermore, the evaluation of hyperaccumulation, phytostabilization or phytoextraction of plant species is not always performed in the same way. Different plant parts are considered as well as different extraction procedures for both plant and substrata element assessment. As a consequence, a direct comparison between obtained data is not always reliable and possible. In this paper the various available indexes are reviewed, highlighting both the similarity and differences between them with the aim of helping the community in choosing the appropriate term for both data evaluation and comparison. In this author's opinion there is no need of new terms to define indexes. I would stress the need for conformity to the original definitions and criteria
Assessment of metal accumulation capacity of Dittrichia viscosa (L.) Greuter in two different Italian mine areas for contaminated soils remediation
No full textThe study aimed at assessing the capacity of Dittrichia viscosa (L.) Greuter to absorb and accumulate in its tissues some
potentially harmful elements (PHEs), as Cd, Cu, Fe, Ni, Pb and Zn, in order to verify its possible use as phytoremediation
in polluted mine soils. Plants from two different Italian mine areas, Montevecchio and Libiola, were considered
and compared with plants from unpolluted areas. In each site (n = 21), both rhizospheric soil materials and D. viscosa
plants were sampled, suitably prepared and analyzed. Soil samples were examined for both total composition (XRF) and
bioavailable fractions (DTPA-extraction). Dittrichia viscosa roots, stems and leaves were analyzed separately to quantify
the metal presence in the different plant parts. The root/soil ratio values calculated on the basis of the total soil concentrations,
displayed a generally scarce capacity of D. viscosa to absorb soils PHEs, especially those more concentrated in the
substrata. Concerning the root/soil ratio calculated on the basis of DTPA-extractable soil metals, values displayed instead
a greater capacity of D. viscosa to absorb metals in the roots thus behaving as a potential phytostabilization plant in both
mine areas.
Regarding the leaf/root ratio, this species also displayed a greater capacity, in sub alkaline mine areas, to shift PHEs
from roots to aboveground tissues, along with Ca transfer, revealing interesting characteristics for phytoextraction. In
sub acid mine areas, this tendency was instead weaker and PHEs tended to be accumulated in all plant parts. Dittrichia
viscosa seems to be appropriate for mine soil stabilization in both sub acid and sub alkaline environments and also for
phytoextraction in the latter
Biorefining of high ligno-cellulosic waste biomass via pyrolysis coupled with anaerobic digestion. An LCA study
No full textThe sustainable processing of biomass into a spectrum of products and energy is the goal of a biorefinery. Sustainability is key in this process and all biorefineries should be designed for sustainability along the entire value chain.
A laboratory-scale plant has been built by the University of Bologna, coupling pyrolysis and anaerobic digestion, in order to treat high ligno-cellulosic waste biomass.
This technology set can bring a wider range of exploitable residual biomasses in anaerobic digestion.
A life cycle assessment has been conducted on the use of corn stover in this experimental plant. The assessment included changes in land-use and soil carbon stock, biochar application to agricultural soils, biomass collection and pre-treatment, and biochar valorization as fertilizer and for carbon storage.
The system is compared to a fossil reference system providing the same set of products.
Results show that the process can yield a net energy gain and reduce GHG emissions, but high variability affects some key parameters, such as the energy required by the pyrolyzer and the biogas output from the anaerobic digester. As for the carbon balance, a relevant contribution is given by carbon storage in biochar
Chemical and pedological features of subaqueous and hydromorphic soils along a hydrosequence within a coastal system (San Vitale Park, Northern Italy)
No full textTransitional systems are complex and fragile ecosystems where the water table oscillation plays a fundamental role in soil and landscape development. Due to global climate change, by the end of the next century a large part of these environments will be affected by water flooding, causing deep changes to soil properties and functionality. Increasing the knowledge on the genesis and properties of these soils can be fundamental for providing useful tools for the correct management of this natural resource. The transition from wetland to hydromorphic interdune system in the coastal area of the S. Vitale park (Northern Italy) represents a unique soil hydrosequence characterized by soils which undergo continuous or partial, permanent or periodic saturation and reduction. These hydrosequences offer a great opportunity to investigate how soil properties change in the transition from subaqueous to hydromorphic soils and to understand which pedogenetic processes mostly characterize the soil development under different water saturation conditions. In this study, the soil transition through the hydrosequence was recognized by the evaluation of some morphological (e.g. Munsell color) and chemical (organic carbon, sulfur ratio, CaCO3 content) soil properties that could trace the extent of sulfidization and decarbonation processes along the soil sequences. The presence of salts of marine origin characterized the subaqueous pedons, while nutrients accumulation (i.e., phosphorous) increased with soil emersion. These hydrosequences represent a soil continuum where the duration of water saturation and the oscillation of the water table along the soil profiles strongly affect some specific soil-forming processes that involve S redox transformation, P accumulation, CaCO3 depletion and salt accumulation
“Monitoraggio della qualità delle acque di bonifica e di irrigazione in funzione della gestione sostenibile delle risorse idriche in ambiente padano"
No full textRelationships between Chemical Characteristics and Phytotoxicity of Biochar from Poultry Litter Pyrolysis
No full textThree biochars were prepared by intermediate pyrolysis from poultry litter at different temperatures (400, 500,
and 600 °C with decreasing residence times) and compared with biochars from corn stalk prepared under the same pyrolysis
conditions. The phytotoxicity of these biochars was estimated by means of seed germination tests on cress (Lepidium sativum L.)
conducted in water suspensions (at 2, 5, and 40 g/L) and on biochars wetted according to their water-holding capacity. Whereas
the seeds germinated after 72 h in water suspensions with corn stalk biochar were similar to the control (water only), significant
inhibition was observed with poultry litter biochars. In comparison to corn stalk, poultry litter generated biochars with higher
contents of ash, ammonium, nitrogen, and volatile fatty acids (VFAs) and a similar concentration of polycyclic aromatic
hydrocarbons (PAHs). Results from analytical pyrolysis (Py-GC-MS) indicated that nitrogen-containing organic compounds
(NCCs) and aliphatic components were distinctive constituents of the thermally labile fraction of poultry litter biochar. The
inhibition of germination due to poultry litter biochar produced at 400 °C (PL400) was suppressed after solvent extraction or
treatment with active sludge. A novel method based on solid-phase microextraction (SPME) enabled the identification of mobile
organic compounds in PL400 capable of being released in air and water, including VFAs and NCCs. The higher phytotoxicity of
poultry litter than corn biochars was tentatively attributed to hydrophilic biodegradable substances derived from lipids or proteins
removable by water leaching or microbial treatments
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
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