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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
Selective Complexation by p-tert-Butylcalix[6]arene in Monolayers at the Water-Air Interface
No full textCalixarene molecules are very powerful ligands for ions and small molecules and for this reason they have been studied with several techniques as models for host-guest systems. In this paper we report the results of a study on the complexation and structural properties of p-tert-butylcalix[6]arene (CAL6) in monolayer at the water-air interface as a function of temperature and subphase composition. The monolayer properties of CAL6 films are fully studied by recording the pi/A spreading isotherms and surface potentials and by calculating the related parameters [limiting area (A(o)), compressibility modulus (C-s(-1)), dipole moment (mu cos theta)]. Changing the temperature (between 20 and 35 degrees C) and the composition of the aqueous subphase (NaCl, KCl, CsCl, guanidinium thiocyanate) produces strong variations on the monolayer parameters, indicating a different selectivity of the CAL6 ligand for the different monovalent cations. In particular, high selectivity in the case of cesium is found. Surface potential measurements as well as limiting area values, compared to CPK model calculations, are discussed in relation to the orientation of the cone-shaped molecules at the water-air interface
Micellar Solutions of Sulfate Surfactants Studied by ESR of Nitroxide Radicals. 2. Use of C6-, C12-, C16- Derivatives of Piperidynil-1-oxy
No full textVariations 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
Micellar Solutions of Sulfate Surfactants Studied By Electron Spin Resonance of Nitroxide Radicals. 1. Use of Neutral and Positively Charged Spin Probes
No full textMicellar Solutions of Sulfate Surfactants Studied by ESR of Nitroxide Radicals. 3. Effect of Added Electrolytes
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