1,720,958 research outputs found
Genetic diversity of Streptococcus thermophilus strains isolated from Italian traditional cheeses
No full textNew Software for the Identification and Characterization of Peptides Generated during Fontina Cheese Ripening Using Mass Spectrometry Data
Full text linkThe aim of this work was to design and implement a new bioinformatics software which is able to identify the protein peptides from the peaks which arise from in-source or MS/MS fragmentation. The oligopeptide fraction was extracted from Fontina cheese at different ages of ripening and subsequently analyzed by LC/MS/MS. On the resulting total ion chromatograms, the peptides were identified by a method based both on the in-source fragmentation detectable with a single-quadrupole mass analyzer and by a new software which was developed. This software performs an in-silico digestion of the major milk proteins, it calculates all the possible peptide fragments which are generated by the loss of the first N- or C-terminal amino acids, and finally, it matches the experimental ion chromatogram with the in-silico which generated theoretical spectrum to identify the exact amino-acid protein sequence of the unknown oligopeptide. With this tool, the useful insights into the proteolytic processes which occur during Fontina cheese aging are obtained, which leads to a better knowledge about the functional features of the proteolysis end product
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
Exploring the microbiota of the red-brown defect in smear-ripened cheese by 454-pyrosequencing and its prevention using different cleaning systems
No full textRed-brown pigmentation can occasionally form in smeared-ripened cheese such as Fontina during the ripening process. This reaction is due to over-development of the typical microbiota present on the rind. Previous studies have demonstrated the relationship between red-brown pigmentation and the traditional utilization of wooden shelves during cheese ripening. The first part of the paper focuses on the characterisation of yeast and bacterial microbiota: plate counts and 454-pyrosequencing were performed in spoiled (n = 6) and non-spoiled cheeses (n = 6) and on the wooden shelves used during ripening. The second part shows different systems tested for cleaning the wooden shelves and avoiding the development of the red-brown defect in cheese: washing with hot water and ozone treatment. Actinobacteria, dominated on the wooden shelves, suggesting to be responsible for the red-brown pigmentation; they were also found in traces in the defected cheese samples. Galactomyces and Debaryomyces were the main species characterizing the yeast population, with Debaryomyces being the most dominant species on the shelves used during ripening of the red-brown defective cheese. Hot water treatment reduced the microbial contamination of shelves, whereas only the ozone treatment ensured complete elimination of both yeast and bacteria, resulting in the cheese rind not having the red-brown defec
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
Microbiota delle scalere coinvolto nella colorazione arancione-rossa del formaggio Fontina: investigazione attraverso 454-pyrosequencing
Full text linkLa Fontina DOP è un formaggio prodotto da latte intero crudo tramite l’aggiunta di ceppi autoctoni starter quali: Streptococcus thermophilus, Lactococcus lactis e Lactobacillus delbrueckii. Durante la maturazione può presentarsi un difetto di colorazione in particolare nella zona del sotto-crosta dove il colore della pasta del formaggio può virare da giallo ad arancione -rosso. Questa colorazione può essere generata da pigmenti prodotti da batteri presenti nel formaggio oppure nel magazzino e sulle scalere di stagionatura. In questo lavoro si è pensato di caratterizzare le specie microbiche sia dei formaggi che delle scalere su cui erano posizionati, per notare qualche correlazione tra colorazione anomala e specie batteriche e di lieviti. La caratterizzazione è stata fatta tramite 454-pyrosequencing della regione V1-V3 del gene 16S rRNA per i batteri e della regione ITS1-ITS4 per i lieviti (la caratterizzazione dei lieviti è stata fatta solo per le scalere e non per i formaggi dove i lieviti erano presenti in quantità non apprezzabili rispetto ai batteri). Sono state analizzate le comunità microbiche di 8 formaggi a colorazione anomala e 8 a colorazione “normale” dopo 3 mesi di stagionatura (il difetto di solito comincia a manifestarsi dopo almeno 1 mese di stagionatura). I formaggi sono stati campionati sia nel sotto-crosta che nel centro. Le scalere in legno di abete rosso sono state campionate in una sezione di circa 250mm2 sulla superficie a contatto con i formaggi. Sono state analizzate 570247 sequenze di batteri divise in 267754 per i formaggi e 302586 per le scalere. Nei formaggi la maggioranza dei batteri apparteneva al phylum Firmicutes (95%) sia nei formaggi colorati in maniera anomala che non, con una piccola percentuale di Proteobacteria. La comunità batterica isolata dalle scalere ha mostrato una biodiversità più grande infatti erano presenti Actinobacteria (48%), Bacteroidetes (31%) Proteobacteria (14%) e Firmuctes (7% ). Sono stati identificati 319 generi di batteri diversi: gli Streptococcus erano dominanti sia al centro che nel sotto-crosta dei formaggi (75%) e ciò era prevedibile considerando che Streptococcus thermophilus è uno degli starter. Sulle scalere le Flavobacteriaceae e le Corynebacteriaceae erano le famiglie batteriche dominanti: le Flavobacteriaceae non presentavano differenze per colorazione (26%) mentre le Corynebacteriaceae mostravano una significativa differenza e in particolare erano più alte sulle scalere che davano colorazioni anomale (28% sulle scalere che davano colorazione e 20% sulle altre).
L’analisi dei lieviti ha rivelato anche in questo caso delle differenze significative ed in particolare le scalere che davano colorazioni anomale presentavano alte percentuali di Galactomyces (33% contro il 13% presente sulle scalere “normali”) e minori di Debariomyces (51% contro 63%) e Tremellomycetes (7% contro 18%).
In conclusione si può dire che la composizione microbica del formaggio non ha mostrato delle differenze apprezzabili ma probabilmente perché con un formaggio dominato dallo “starter” è fondamentale analizzare molte più sequenze per avere un’idea del contributo che possono avere anche le popolazioni sub-dominanti quindi sarebbe necessaria un’analisi più approfondita. Per le scalere si può affermare che laddove si verifichino colorazioni anomale” c’è una significativa dominanza di Corynebacteriaceae e Galactomyces rispetto alle altre scalere dove invece dominano Debariomyces e Tremellomycetes.
Sono da indagare possibili correlazioni di questi generi batterici e di lieviti nelle colorazioni anomale
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