1,721,004 research outputs found
Application of a HRGC method on capillary column Rtx 65-TG for triglyceride analysis to monitor butter purity.
No full textIn this article a new analytical method is proposed for the detection of extraneous fats fraudulently added to butter. The determination is carried out by gas chromatographic analysis of butter triglycerides on a capillary column having 65% phenylmethylsilicone as stationary phase. Over the past 25 years, various methods for the evaluation of butter purity have been proposed. The detection of adulterating vegetable oils is based on sterol analysis and the presence of these vegetable sterols in butter represents clear evidence of fraud. The official EU method for the detection of animal fats such as lard and tallow is time consuming and tedious; there are also problems of reproducibility and accuracy at low concentrations of the additives. The method proposed in this article allows us to detect the presence of extraneous vegetable and animal fats in a simple, rapid and precise way even when the quantity added to butter is minimal. The analysis is based on the best currently achievable resolution of single triglycerides components and a comparison with the profile observed for reference samples of certifiably pure butters. Moreover, by comparing each single sample analyzed with the EEC “BCR 164 RM” butter standard taken as reference, the present procedure can be used not only to evaluate purity but also to introduce a new parameter, “quality.” The latter is defined as the similarity between the sample percentages of single triglycerides with those in butter standards. The proposed method is simple and easy to execute, even by a nonspecialist technical staff
Quality control of butter by means of capillary column RTX 65-TG
No full textIn this paper a new analytical method for the detection of extraneous fats fraudulently added to butter is proposed. Such determination is carried out by gas chromatographic analysis of butter triglycerides, using a capillary column for triglycerides having 65% phenyl methyl silicone as stationary phase. During the last twenty years, different methods for evaluation of butter genuineness were proposed. The presence of vegetable oils mixed with butter is based on sterol analysis; the revelation of vegetable sterols in butter represents a clear evidence of fraud. The Official EU method for detection of animal fats in butter, as lard and tallow, is time consuming, it often brings to not easily reproducible results and it is not of great accuracy especially in the cases of small additions of extraneous fats. The method proposed in this paper allows to detect the presence of extraneous vegetable and animal fats in a simple, rapid, and precise way, even if the quantities added to butter are minimum. The analysis is based on the best resolution, actually achievable, of single triglyceride components and their comparison with those present in certainly genuine butters, taken as reference
Recherches sur un appareil qui se trouve sur les poissons du genre des Raies (Raia, C.): Et qui présente les caractères anatomiques des organes électriques
No full textRECHERCHES SUR UN APPAREIL QUI SE TROUVE SUR LES POISSONS DU GENRE DES RAIES (RAIA, C.): ET QUI PRÉSENTE LES CARACTÈRES ANATOMIQUES DES ORGANES ÉLECTRIQUES
Johannes Müller Library (-)
Recherches sur un appareil qui se trouve sur les poissons du genre des Raies (Raia, C.): Et qui présente les caractères anatomiques des organes électriques (-
Stability control and genuineness evaluation of lemon liquor: use of dynamic head space
No full textDynamic head space GC anal. technique was used to gather rapidly important data on the genuineness and stability of lemon liquor. Immediately after lemon liquor prepn., 1-L samples were sealed in bottles and stored in dark at room temp. After 1 h, without shaking the bottle, 1 mL of the liq. from the free liquor surface was taken by micropipette and transferred into 20-mL vial for dynamic head space GC anal. Close to 30 peaks were sepd. and a few identified as α-pinene, β-pinene, β-myrcene, limonene, and γ-terpinene. The data gave qual./quant. indications about the volatile components of lemon liquor and allowed to make some prognosis on the phenomenon of floating of essential oils to the surface which leads to the formation of unsightly "collarino" defect and seriously worsens the product marketing quality
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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