1,720,958 research outputs found
Residui di idrocarburi clorurati aromatici (PCB,PCT,PCN) in dializzatori per nefrologia.
No full textMeccanismi di inquinamento di acquiferi alluvionali determinati dalla ricaduta a terra dei vapori provenienti da cicli di lavorazione industriali. Il caso del fiume Chienti (Marche).
No full textEFFECT OF L-PROPIONYL CARNITINE ON SOME PROPERTIES OF ERYTHROCYTES AND LEUKOCYTES OF ALCOHOL ABUSERS
No full textThe effect of L-propionyl carnitine, the carnitine derivative utilized as a more effective drug for membrane protection, on Na-K ATPase activity of erythrocyte gh os ts of alcohol-dependent patients and blood donors has been investigated The effect of L-propionyl carnitine on leukocyte chemotaxis and cytochrome c reduction, a measure of superoxide ion production, was also studied. It has been in fact observed that alcohol is immunotoxic on both the non-specific and the specific immune response. In alcohol-dependent erythrocytes, a significant higher value of the H-1-NMR spin lattice relaxation time (T1) was observed as compared to blood-donor erythrocytes. The in-vitro addition of ethanol increases the T1 values of blood donor erythrocytes, whereas it is without effect on the T1 value of alcohol-dependent erythrocytes. The Na-K ATPase activity is higher in alcohol-dependent erythrocyte ghosts as compared to blood-donor ghosts. A non-significant increase of the Na-K ATPase activity of blood-donor ghosts was observed with the increasing of L-propionyl carnitine concentrations (from 0.2 to 5.0 mM), whereas the Na-K ATPase activity of alcohol-dependent ghosts decreases. From these combined effects the differences of Na-K ATPase activity progressively decrease with the increasing of L-propionyl carnitine concentration, and no significant differences are observed between the two groups at L-propionyl carnitine concentrations higher than 0.5 mM. The in-vitro addition of ethanol increases the enzyme activity to a greater extent in blood-donor ghosts as compared to alcohol-dependent ghosts. This in-vitro activation by ethanol is decreased by the addition of L-propionyl carnitine. The chemotaxis induced by N-formyl-methionyl-leucylphenylalanine and the superoxide anion production stimulated by zymosan is significantly lower in alcohol-dependent neutrophils. L-Propionyl carnitine increases, in a dose-dependent way, both chemotaxis and superoxide anion production of alcohol-dependent neutrophils, and no significant difference was observed between the two groups at 5 mM L-propionyl carnitine. These experimental results suggest that L-propionyl carnitine administration may be useful for reducing some acute and chronic damages due to alcohol ingestion. The protective and modulatory actions of L-propionyl carnitine may be even more evident in cells and tissues different from those investigated in this study and in which ethanol determines several biochemical damages
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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