1,720,981 research outputs found
Investigation of commercial lecithin by 31P NMR in a ternary CUBO solvent
No full textMany different ways have been devised over the years for analyzing phospholipids in soln. by 31P NMR. One promising method entails the use of the so-called CUBO solvent, a ternary mixt. of DMF, triethylamine and guanidinium hydrochloride. As this interesting system seems to have been overlooked in the literature, we present here a study on the quantification of phospholipids and lysophospholipids contained in 10 samples of com. lecithin using the CUBO/31P NMR method. Cluster anal. and principal component anal. of the NMR data showed clear differences among the samples according to the actual lecithin producer. Multivariate anal. of the chem. and phys. parameters of the samples confirmed these differences
Relationships between raw broiler breast meat colour and Low-Resolution NMR relaxation properties
No full textIt is now well established that colour variations from dark, firm and dry (DFD-like) and pale, soft and exudative (PSE-like) poultry meat are associated with variations of water holding capacity (WHC) properties. The study of LR-NMR relaxation properties, and in particular the values of transverse (T2) relaxation, can give relevant information about meat WHC. To assess the existence of a direct connection between meat colour and T2 relaxation, 36 pale (L*>56), 36 normal (L* between 50 and 56) and 36 dark (L*<50) whole breasts (n=108) were selected from a commercial processing plant at 24 h post mortem, using a Minolta Chroma meter CR-300. The limit values were chosen according to the broiler breast meat L* values distribution previously found in the same processing plant. At 24 h post mortem the ultimate pH (pHu) and colour (L*a*b*) were determined on each fillet (n=216). Subsequently, the right fillet from each breast (n=108) was kept intact and used to determine the intact meat cooking loss, tenderness (Allo-Kramer shear) and NMR transverse relaxation. The left fillet (n=108) was ground and used to determine the ground meat cooking loss, tenderness and NMR transverse relaxation. The pHu values of dark, normal and pale groups significantly differ from each other (P<0.01) and confirm that higher pH values (an average value of 6.04) are associated with darker meat (L*=48.3) while lower muscle pH values (5.77) are associated with lighter meat (L*=57.5). Pale breast meat whether intact or ground exhibit the greatest (P<0.01) cooking losses (23.8 and 27.7%, respectively) compared to normal (21.1 and 24.7%) and dark (18.8 and 21.0%) groups. No differences were found in the meat tenderness among the three groups. Linear discriminant analysis of the raw LR-NMR data shows three distinct types of meat according to the colour group. There is a significant correlation between the LR-NMR signal and lightness as assessed by means of the relative standard deviation principle component regression (RSDPCR). The results confirm that extreme colour variations in broiler breast meat, mainly due to the pH effect, are significantly related to its water holding capacity. The highly significant correlation found between LR-NMR signal and meat quality parameters suggests that LR-NMR technique could be adopted to discriminate broiler breast meat properties for further processing
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
A case study development of chemical indexes, originated from the application of chemometric methods to the Nuclear Magnetic Resonance (NMR), in the assesment of the quality and of the geographical origin of vegetable products
Get PDFkoamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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