1,720,972 research outputs found
C’è vita nell’intestino: la risposta microbica allo stress
No full textSome probiotic bacteria are capable of producing and delivering neuroactive substances such as gammaaminobutyric acid and
serotonin, which act on the gut-brain axis. Emerging evidence suggest the benefit of probiotic in alleviating symptoms of depression and in chronic fatigue syndrome. Such benefits may be related to the anti-inflammatory actions and the ability to
reduce hypothalamicpituitary-adrenal axis activity
Cell wall components of a Lactobacillus brevis strain inhibit herpes simplex virus type 2 replication
No full textBacteria-free supernatant of Lactobacillus brevis strain CD2 grown in cell culture medium inhibits herpes simplex virus type 2 (HSV-2) replication in cell culture independently from H2O2 or lactic acid. The mechanisms of action and the bacterial factors responsible for the antiviral effect were studied using bacterial extracts obtained by sonication of L. brevis cells or by lysozyme/antibiotic treatment of the microorganism. The antiviral activity of bacterial cell wall was also studied. Bacterial extract and cell wall were not toxic to cells at the maximal concentration tested (3 mg/ml protein). Both the extract and the cell wall fraction showed a dose-dependent inhibitory activity on HSV2 multiplication when present on Vero cells before virus adsorption and during infection.
The inhibition was exerted on the first phases of virus replication cycle. The inhibitory activity was resistant to a 30 minutes treatment at 100°C. DNA and lipids obtained from bacterial extract were devoid of any inhibitory effect. S-layer of bacterial cell-wall containing several heat-resistant molecules (teichoic and lipoteichoic acids, lipoglycans, teichuronic acids and other acidic or neutral polysaccharides) was removed by treatment with LiCl without affecting bacterial viability. Bacterial extract and cell-wall fragments obtained after LiCl treatment showed a dramatic reduction in the antiviral activity suggesting that cell wall components of L. brevis released in bacterial supernatant after sonication or lysozyme/antibiotic treatment are responsible for the inhibiting activity against HSV-2
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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