1,720,959 research outputs found
Detector elettrochimico ECD (Coularray®): applicazione nel settore enologico per la determinazione di sostanze antiossidanti
No full textC
Organic acids profile in tomato juice by HPLC with UV detection
No full textA simple method was developed to determine 10 organic acids simultaneously
in tomato products using reverse-phase high performance liquid chromatography
(HPLC) column with the diode array detector set at 210 nm. After
centrifugation and filtration, the samples were passed through to an anion
exchange resin and the organic acids were released using 0.1 N HCl. The
chromatographic separation was achieved with isocratic analysis in a 20-min
run. The method was reliable and sensitive. The coefficient of determination of
the standard calibration curve is 0.9925 r2 0.9999 and the limit of detection
ranged from 0.08 to 6.00 mg/kg for trans-aconitic acid and acetic acid,
respectively. The limit of quantification ranged from 0.19 to 15.18 mg/kg for
trans-aconitic and acetic acid, respectively. To establish the efficiency of the
anion resin the procedure was applied to a standard solution of a mixture of
organic acids. The organic acids recovery ranged from 87.0% 1.9 for citramalic
acid to 109.9% 5.2 for fumaric acid
Moisture content determination of colored malts
No full textThe present paper deals with the validation
of a method to determine the
moisture content of roasted and caramel
colored malts. The data agree with
those reported in the literature, but
differ with respect to the tested validation
range
Quality control of malt: turbidity problems of standard worts given by the presence of microbial cells
No full textSince the main effect on beer colour originates from the chemical composition of malt, the measurement of the colour of won obtained from malt is one of the most important quality parameters to be controlled. Malt colour determination is usually performed spectrophotometrically on EBC Congress worts, which are generally bright. The quality control on the malt harvested in the year 2007 highlighted a problem of turbid Congress wort, for a part of Northern Europe samples analyzed, and therefore the spectrophotometric determination of the colour of wort was not possible. Thus both analytical screening of the quality parameters of malt and the scanning electron microscope (SEM) were used to identify the nature of the turbidity in the worts. The results obtained suggested that the nature of the turbidity of Congress worts could have been due to microbial contamination of the barley, enhanced in particular by the rainy harvest and the consequent formation of exopolysaccharides (EPS) by stressed yeast and bacteria during malting
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
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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