1,720,984 research outputs found
Commercial advantages on basil architecture by ultraviolet-B irradiation
Full text linkSweet basil (Ocimum basilicum L.) is one of the most important herbs widely used for its medicinal properties and as food ingredient. The marketing of this product highlights the problem that these plants have long and slender stems, which are easy to break off and thus making difficult their market distribution. In this work, two cultivars of basil (Genovese and Profumo) at the adequate development stage for sale were used. We evaluated the effect of supplemental ultraviolet (UV)-B irradiation (15 W m-2; 3 h day-1) on plant growth and market quality. Both cultivars of basil plants under UV-B irradiation resulted in increased leaf size and biomass, and decreased shoot length in comparison to that of under control growth conditions. These results indicate that the application of UV-B irradiation beneficially influenced plant architecture in basil improving their greenhouse production for fresh market
Screening of trace metal elements for pollution tolerance of freshwater and marine microalgal strains: Overview and perspectives
Full text linkMicroalgae represent a putative solution to decontaminate metal polluted aquatic sites (phycoremediation). Seven different freshwater and seawater microalgal strains (Nannochloropsis sp., Dunaliella sp., Phaeodactylum sp., Chlorella sp., Isochrysis sp., Euglena sp. and Chlorogonium sp.) were exposed to five metals (Cu, Zn, As (III), Fe and Ni) at three concentrations each, simulating highly polluted sites. The experiment was conducted for a week; the survival ability of each strain and the photosynthetic pigments content (chlorophyll a, b and carotenoids) were evaluated, together with the Optical Density of each culture, pH, growth rate and biomass. Results highlighted different resistance patterns towards metals characterizing each algal strain, and the tolerance of all the microalgal strains towards arsenite. For the first time, the metal resistance pattern of Chlorogonium sp. was evaluated. Finally, our Euglena sp. and Dunaliella sp. strains were considered among the most promising organisms for phycoremediation of freshwater and seawater polluted sites respectively
Redox activity of caffeic acid towards iron (III) complexed in a polygalacturonate network
No full textThe transfer of several metal ions from the soil to the plant absorbing cells is mediated principally by organic molecules of low molecular weight with complexing and reducing activity, among which caffeic acid (CAF) is particularly important. Here we report the results of a survey which deals with the oxidation of CAF by the Fe(III) ions bound to a polygalacturonate network (Fe(III)-PGA network). The interaction between Fe(III) and CAF was studied by using Fe(III)-PGA networks equilibrated in the 2.4-7.0 pH range by means of kinetic and spectroscopic methods. The reducing power was found to depend on the nature of the Fe(III)-PGA network complexes: when the ferric ion was complexed only by the PGA carboxylic groups, a high redox activity was observed, whereas the Fe(III) reduction was found to be lower when a hydroxylic group was inserted in the Fe(III) coordination sphere. The iron complexed in the network was protected from hydrolysis reactions, as shown by the high pH values at which its reduction occurred. Two different fractions of Fe(II) produced were identified, one diffusible and another exchangeable with CaCl2 6.0 mM. The existence of the exchangeable form was attributed to the electrostatic interaction of the Fe(II) ions with the carboxylate groups of the fibrils and with the degradation products of CAE The arrangement of the fibrils was altered following the substitution of Ca(II) by Fe(III) ions and was restored following the seduction of Fe(III) by CAF
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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