1,720,962 research outputs found
Total synthesis of (-)-elisapterosin B and on towards the metabolites of Pseudopterogorgia elisabethae
No full textEThOS - Electronic Theses Online ServiceGBUnited Kingdo
Contribution to the assessment and conservation of biodiversity: inventory of some model taxa from Sardinian caves
No full textInteraction of the water soluble fraction of MSW-composts with Pb(II) and Cu(II) ions
No full textIn this study we report on the interactions between the water-soluble fraction (WSF) of two municipal solid waste composts (C1- and C2-WSF) with Pb(II) and Cu(II) ions at pH 4.5. The Me(II) addition to the compost-WSFs led to the formation of soluble Me(II)-organic complexes (as highlighted by FT-IR spectroscopy), and to a decrease of the trace metals' solubility, which was greater for Pb(II) than Cu(II). This was due to the formation of insoluble Me(II) complexes involving the water-soluble organic carbon (WSOC) and the inorganic anions within both WSFs [1.10 and 0.62 mmol L−1 and 2.06 and 0.42 mmol L−1 of Pb(II) and Cu(II) precipitated from C1- and C2-WSF respectively, when 6.4 mmol L−1 Me(II) was added]. A loss of WSOC from both WSFs, i.e. ∼13% and <5%, was detected in the systems containing 6.4 mmol L−1 Pb(II) and Cu(II) respectively. A significant contribution in the formation of Pb(II) precipitates was also due to phosphate, chloride and sulphate anions, since their concentrations in the WSF decreased of 80, 25 and 90%, respectively, after the addition of 6.4 mmol L−1 Pb(II). A decrease of phosphate anions in both WSFs (∼30%) was found in the systems containing Cu(II)
Influence of lead in the sorption of arsenate by municipal solid waste composts: metal(loid) retention, desorption and phytotoxicity
No full textThe ability of two municipal solid waste composts (MSW-C) to sorb As(V) in the presence of Pb(II) and in acidic conditions was investigated. Sorption isotherms and kinetics showed that both MSW-C were able to sorb As(V) in a similar way (similar to 0.24 mmol g(-1) MSW-C), but only when Pb(II) was present (0.45 mmol L-1). The concomitant sorption of Pb(II) by both MSW-C (similar to 0.40 mmol g(-1)) suggested that the metal cation was likely acting as bridging element between the negatively charged functional groups of composts and As(V). SEM-EDX analysis of the MSW-C + Pb(II) + As(V) systems supported the association between Pb(II) and As(V), while sequential extraction procedures and organic acids treatment showed that As(V) was strongly retained by MSW-C + Pb(II) and suggested the presence of different interaction types between As(V) and Pb(II). Plant growth experiments highlighted the key role of Pb(II) in the reduction of As(V)-phytotoxicity for triticale plants (x Triticosecale Wittm.) in the presence of MSW-C
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
Planarians of temporary waters (Platyhelminthes, Tricladida)
No full textFreshwater planarians are fragile animals susceptible to desiccation and high temperature and characterized by a poor dispersal power requiring contiguous freshwaters to survive and disperse. They are indeed excellent biogeographic models. However, some species of Planariidae (generaPhagocataandHymanella) and Dugesiidae (genusSpathula) are known inhabiting temporary waters particularly from the Nearctic, Palaearctic and Australasian regions
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
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