1,720,965 research outputs found
Formazione di depositi cerosi in foglie di Salix L.
No full textE' stato seguito il processo di formazione dei depositi cerosi su foglie di salice bianco dalle gemme dormienti alle foglie matur
Accumulation and effects in Salix fragilis of an antibacterial sulfonamide
No full textAccumulation and effects in Salix fragilis of an antibacterial sulfonamide
Lucia Michelini, Franco Meggio1, Paolo Paiero and Rossella Ghisi*
Department of Biotecnologie Agrarie, University of Padova, Italy
1Department of Agronomia Ambientale e Produzioni Vegetali, University of Padova, Italy
The application of contaminated manure to fertilize agricultural soils is among the major routes through which antibacterial sulfonamides (SAs) enter the environment. SAs can be easily leached into groundwater, due to their persistence and low sorption to soil constituents. In effect, the presence of these compounds in soil, surface water and groundwater are frequently reported. Previous results showed that barley plants are able to accumulate high amount of SAs from nutrient solutions. Salix is currently under intensive research for its potential use in soil phytoremediation. In this study we evaluated the possibility to use willows to remediate soils/groundwater contaminated with SAs, by studying both the ability of these plants to absorb sulfadimetoxine (SDM) and to tolerate it. The experiments were conducted with Salix fragilis cuttings grown hydroponically in a climate chamber. Once rooted and with leaves, plants were exposed to different concentrations of SDM (0.04 to 3 mM) for a month. At fixed time intervals photosynthetic (LI-COR 6400) and growth parameters were measured. At the end of the experiments plants were analysed for their content in sulfadimetoxine. Photosynthetic pigments and chlorophyll fluorescence were also analysed to obtain further information on response of willow to sulfonamides.
Results show that Salix fragilis growth (leaf and stem length), photosynthetic pigment contents, chlorophyll fluorescence parameters and transpiration are not influenced by the treatment, however, the measures of CO2 fixation during leaf development indicate a lower photosynthetic rate in treated plants than in controls, which must be studied. Roots accumulated high amount of SDM, whereas leaves did not show the presence of the antibacterial substance.
In conclusion our results indicate that willow is a promising specie in the phytoremediation of sulfonamides, however further researches are needed to analyse plant response to lower, more realistic sulfonamide concentrations and to evaluate the response of different Salix species
Aspetti dell'anatomia e fine morfologia fogliare in carpino nero (Ostrya carpinifolia Scop.)
No full textSono stati esaminati alcuni aspetti dell'anatomia e della fine morfologia di foglie, rami e radici del carpino nero suscettibili di una interpretazione fisioecologic
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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