1,720,996 research outputs found
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
Copper(II) complexes of the imidazolinone herbicide imazapyr
No full textThe copper(II) complexes formed by the imidazolinone herbicide imazapyr [(±)-2-(4-isopropyl-4-methyl-5-oxo-2-imidazolin-2-yl)nicotinic acid] were studied in aqueous solution by potentiometric and spectroscopic techniques. Imazapyr acts as a chelating molecule and is effective over a wide pH range. The chelating set active in acidic media involves rather weak donors, namely the pyridine and imidazole nitrogens. In neutral media, the lactam site of the imidazolinone ring deprotonates and the ligand takes advantage of a rather basic nitrogen atom, which, assisted by the pyridine donor, yields stable complexes with five-coordination at the metal ion
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
Specific interactions of bovine and human beta-casomorphin-7 with Cu(II) ions
No full textComplex formation between Cu(II) and human and bovine beta-casomorphin heptapeptides. Tyr-Pro-Phe-Val-Glu-Pro-Ile and Tyr-Pro-Phe-Pro-Gly-Pro-Ile, respectively, was investigated by pH potentiometry and spectroscopic (CD, EPR and electronic absorption) techniques. The results showed the critical impact of Pro residues on the complex equilibria formed. The presence of the Pro residue at the second position leads to formation of very stable dimeric species in which two metal ions co-ordinate to N-terminal {NH2,C=O} binding sites of one peptide molecule and the deprotonated phenolic oxygen of the second ligand molecule. The presence of two additional hydrophobic residues on the C-terminal makes heptapeptide molecule much more effective ligand than its pentapeptide N-terminal fragment. (C) 1998 Elsevier Science Inc. All rights reserved
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
Binding ability of Cu2+ ions by opiate-like fragments of bovine casein
No full textThe coordination modes of Cu(II) to alpha-casein (90-95) and alpha-casein (90-96) peptides with opioid activity isolated from pepsin hydrolisates of alpha-casein were investigated by means of electron paramagnetic resonance, absorption, and circular dichroism spectroscopy and potentiometry. The results allow the identification of the complex species involved and the attribution. of the spectral data set to the various complex structures. According to the spectroscopic data, a phenolate side-chain of Tyr residue belonging to the Gly-Tyr-Leu or Gly-Tyr-Leu-Gln fragment of the peptides is involved in the metal coordination in a complex which is a minor species at neutral pH range. (C) 1997 Elsevier Science Inc
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