1,721,014 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
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
Using GIS for modelling the impact of current climate trend on the recharge area of the S. Susanna spring (central Apennines, Italy)
No full textThough the S. Susanna spring system is one of the biggest water sources in the central Apennines, its hydrogeological dynamics have been scarcely investigated. This study tried to clarify some of the factors controlling the recharge/discharge processes of this spring by modelling the available climate series, water balance equations and new isotopic and quantitative data, using statistical and raster overlay functions embedded in a Geographic Information System (GIS). Oxygen and hydrogen isotopic data were recorded monthly over a 2-year period at the spring itself and in eight rain gauges in Reatini Mountains. The effective infiltration rate was calculated using the Kennessey coefficients and the Turc equation. Finally, the recharge area was identified with the help of an expert evaluation procedure. Local delta(18)O and delta D versus altitude regression curves were used to validate the digital recharge model by comparing their expected values with the values actually measured. Recharge process was framed within the perspective of the ongoing local climate trends. The current discharge rate of 4.1 m(3).s(-1) is significantly lower than the average value of 5.5 m(3).s(-1) measured up to the 1980s, confirming the fall in the recharge/discharge rate. The hydrogeological system shows a delayed response, due to an average groundwater residence time in the aquifer, which is estimated to be about 15/20 years on the basis of the offset between calculated and observed isotope data at the main spring. For this reason the system is presently not equilibrated and is gradually changing towards a final equilibrium discharge estimated in about 3.4 m(3).s(-1). Copyright (C) 2009 John Wiley & Sons, Ltd
DOUBLE STEREOSELECTION IN THE SULFOXIDATION REACTION CATALYZED BY TITANIUM COMPLEXES OF N-SALICYLIDENE-L-AMINO ACIDS
No full textCATALYTIC ASYMMETRIC WEITZ-SCHEFFER EPOXIDATION PROMOTED BY BOVINE SERUM-ALBUMIN .2
No full textThe epoxidation of 2 and 2,3-substituted naphthoquinones with t-BuOOH in aqueous buffer solutions, in the presence of bovine serum albumin (BSA) as chiral catalyst, affords the corresponding epoxynaphthoquinones with enantiomeric excess (e.e.) up to 79%. The influences on the enantioselectivity of the pH of the buffer solution, of the oxidizing agent, and of inorganic salts have also been examined
Asymmetric oxidation of sulphides to sulphoxides catalysed by titanium complexes of N-salicylidene-L-amino acids
No full textOxidation of alkyl aryl and heterocyclic sulphides with ButOOH and a catalytic amount of titanium N-salicylidene-L-amino acids (0.1 mol equiv.) affords the corresponding sulphoxides with an enantiomeric excess (e.e.) up to 21%. The use of other metal complexes with the same ligands led to racemic products
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
- …
