1,721,228 research outputs found
Biostimulants derived from organic urban wastes and biomasses: An innovative approach
Full text linkWe used humic and fulvic acids extracted from digestate to formulate nanohybrids with potential applications in agronomy. In order to obtain a synergic co-release of plant-beneficial agents, we functionalized with humic substances two inorganic matrixes: hydroxyapatite (Ca10(PO4)6(OH)2, HP) and silica (SiO2) nanoparticles (NPs). The former is a potential controlled-release fertilizer of P, and the latter has a beneficial effect on soil and plants. SiO2 NPs are obtained from rice husks by a reproducible and fast procedure, but their ability to absorb humic substances is very limited. HP NPs coated with fulvic acid are instead a very promising candidate, based on desorption and dilution studies. The different dissolutions observed for HP NPs coated with fulvic and humic acids could be related to the different interaction mechanisms, as suggested by the FT-IR study
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
Effect of grafting solvent in the optimisation of Sba-15 acidity for levulinIc acid production
Full text linkValorisation of lignocellulosic biomass for chemical production is one of the main challenges of the 21st century. Levulinic acid (LA) has been chosen as the target product due to its potential as an intermediate to produce a wide variety of other chemicals. The attention has been focused on the formulation of an active solid acid catalyst for the hydrolysis of glucose to LA. Therefore, a deep modification of SBA-15 with sulfonic groups was performed using post-synthesis grafting method. In particular, this work focuses on the role of different grafting solvents. Since the traditional solvents such as toluene or hexane, are flammable and toxic, a safer and more environmentally friendly solvent, a mixture of water and NaCl has been investigated. It was found that the nature of the solvent highly affects the morphological and chemical features of the materials. Thus, the best catalytic results were obtained with the catalyst prepared in water and NaCl; indeed 30 % and 16 % of LA yield were obtained from fructose and glucose hydrolysis at 180 °C respectively. Water and NaCl mixture guarantees the best distribution of sulfonic groups over the surface, leading to the most balanced acid catalyst.Valorisation of lignocellulosic biomass for chemical production is one of the main challenges of the 21st century. Levulinic acid (LA) has been chosen as the target product due to its potential as an intermediate to produce a wide variety of other chemicals. The attention has been focused on the formulation of an active solid acid catalyst for the hydrolysis of glucose to LA. Therefore, a deep modification of SBA-15 with sulfonic groups was performed using post-synthesis grafting method. In particular, this work focuses on the role of different grafting solvents. Since the traditional solvents such as toluene or hexane, are flammable and toxic, a safer and more environmentally friendly solvent, a mixture of water and NaCl has been investigated. It was found that the nature of the solvent highly affects the morphological and chemical features of the materials. Thus, the best catalytic results were obtained with the catalyst prepared in water and NaCl; indeed 30 % and 16 % of LA yield were obtained from fructose and glucose hydrolysis at 180 °C respectively. Water and NaCl mixture guarantees the best distribution of sulfonic groups over the surface, leading to the most balanced acid catalyst
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
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Innovative Synthetic Approaches for Sulphate-Promoted Catalysts for Biomass Valorisation
Full text linkIn the present research, we report on an innovative and quick procedure for the synthesis
of metal oxides: a sol-gel procedure which is followed by two steps that are assisted by microwaves
(MW) heating. First, MW heating promotes gel drying and successively permits the calcination of the
xerogel in a few minutes, using a susceptor that rapidly reaches high temperatures. The procedure
was employed for the synthesis of zirconium dioxide (ZrO2), and MW-assisted calcination enables
the collection of tetragonal ZrO2, as confirmed by different experimental techniques (PXRD, HR-TEM
and Raman spectroscopy). Using this MW-assisted sol-gel procedure, a promoted sulphated zirconia
(SZ) has been obtained. Both the nature and strength of SZ surface acidity have been investigated with
FTIR spectroscopy using CO and 2,6-dimethylpyridine (2,6-DMP) as probe molecules. The obtained
materials were tested as catalysts in acid hydrolysis of glucose to give 5-(hydroxymethyl)furfural
(5-HMF). One of the obtained catalysts exhibited a better selectivity towards 5-HMF with respect
to SZ material prepared by a classical precipitation route, suggesting that this procedure could be
employed to obtain a well-known catalyst with a less energy-consuming procedure. Catalytic results
also suggest that good selectivity to 5-HMF can be achieved in aqueous media in the presence of
weak Lewis and Brønsted sites
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