1,720,961 research outputs found
Pyroglutamyl-γ3-casein as marker of proteolysis and ripening period of Grana Padano and Parmigiano Reggiano cheeses
No full textGrana Padano (G.P.) and Parmigiano Reggiano (P.R.) are extra-hard, long ripened PDO cheeses and, during maturation, they undergo to extensive proteolysis. Different chemical indices related to proteolysis and ageing period have been investigated in G.P. (n=155) and P.R. (n=27) cheese samples aged from 7 to 38 months, by means of ion exchange chormatography and capillary electrophoresis (CE). The levels of intact caseins, γ-caseins and free amino acids were measured but showed low correlation with the ripening period as they varied among samples of the same age. A peptide, identified by means of HPLC/electrospray ionization-mass spectrometry as pyroglutamyl-γ3-CN (pγ3-CN), resulted from cyclization of N-terminal GLU of γ3-CN into pyroglutamic acid. According to CE electropherograms, this peptide accumulated as a function of cheese age. Based on the peak area ratio of pγ3-CN and γ3-CN, an algorithm suitable to determine the cheese age was proposed and adopted to verify the typicalness and the ripening period of the two G.P. categories “G.P. ripened over 16 months” and “G.P. Riserva” (i.e. ripened over 20 months)
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
Shedding light on crystals and white spots in cheese
Full text linkMicroscopy is a powerful research tool in food science, although a number of difficulties in sample preparation may discourage its use. Investigation at structure and ultrastructure level helps to understand changes and interactions the raw material components undergo when processed into food. We have adopted various microscopy techniques to study the nature and origin of different types of crystals and spots originating in hard cheeses during ripening. Although not directly affecting the flavor, in this type of cheese they are considered a desired attribute. Compositional, biochemical and microbiological data were obtained on the same samples to support the microscopy study.
In hard cheeses upon ripening, protein is progressively degraded into free amino acids. After 10-12 month ripening, free amino acids represent more than 20% of the cheese protein. This fact largely contributes to increase the concentration of solutes in cheese water phase, where sodium chloride, calcium, phosphates, lactate and other soluble molecules are already present. Crystals of tyrosine, calcium lactate and calcium phosphate are already reported to occur in some cheese varieties, such as Cheddar, Gouda, Emmental, Grana Padano and Parmigiano-Reggiano, due to the decreased solubility as the cheese water content decreases. In addition, non-crystalline spherical spots are reported to occur in the last two cheeses, sometimes named as “pearls” and whose origin is not yet understood. We have focused our attention on those pearls and investigated their structure and ultrastructure for the first time. The matrix, as observed by both optical and confocal microscopy after suitable staining procedures, appeared to be rather homogeneous but more compact with respect to the surrounding cheese portion from which the pearl is clearly distinguishable, with several crystals embedded. By TEM of the resin embedded material, the crystals showed a star-shaped core surrounded by a thick layer of dense material. The nature of the different components of the crystals was further investigated by confocal microscopy, confocal Raman microscopy and compositional data, and a possible role of some free amino acids as seeding components was hypothesized
New insight on crystal and spot development in hard and extra-hard cheeses : Association of spots with incomplete aggregation of curd granules
Full text linkChemical composition and structure of different types of macroparticles (specks, spots) and microparticles (microcrystals) present in hard and extra-hard cheeses were investigated. Light microscopy revealed that the small hard specks had the structure of crystalline tyrosine, as confirmed by amino acid analysis. Spots showed a complex structure, including several curd granules, cavities, and microcrystals, and were delimited by a dense protein layer. Spots contained less moisture and ash than the adjacent cheese area, and more protein, including significantly higher contents of valine, methionine, isoleucine, leucine, tyrosine, and phenylalanine. Microcrystals were observed by light and electron microscopy and analyzed by confocal micro-Raman. Among others, calcium phosphate crystals appeared to consist of a central star-shaped structure immersed in a matrix of free fatty acids plus leucine and phenylalanine in free form or in small peptides. A hypothetical mechanism for the formation of these structures has been formulated
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
koamabayili/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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