1,721,021 research outputs found
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
Bacteriolitic effect of teicoplanin.
No full textThe glycopeptide antibiotic teicoplanin belongs to the same group as vancomycin and ristocetin and is a valuable tool for studying the autolytic system of sensitive Gram-positive bacteria. Teicoplanin, at a concentration of 1 microgram ml-1, caused rapid lysis of exponential phase cells of Streptococcus faecalis. Bacillus spp. were most sensitive to the antibiotic; effective lysis occurred at 0.1 microgram teicoplanin ml-1. The bacteriolytic effect depended on the antibiotic concentration, the growth phase and growth rate of the target organism. Antibiotic added to overnight cultures did not cause lysis. Mg2+ (50 mM) was unable to prevent lysis. Mutants with decreased autolytic activity were more resistant to teicoplanin and lysed more slowly than the wild-type. Growth of bacteria in slightly acidic medium protected the cells against the lytic effect of teicoplanin typically observed at pH 7 or 8. This pH-dependent antibiotic tolerance was demonstrated with both bacilli and streptococci. Bacterial lysis was prevented by the presence of Ac-L-Lys(Ac)-D-Ala-D-Ala and normal growth was observed when this peptide was added simultaneously with teicoplanin. Bacteria pretreated with teicoplanin, washed and transferred to fresh medium or buffers behaved as if the antibiotic was still present; in neutral or slightly alkaline conditions strong lysis occurred, whereas in acidic buffer only bacteriostasis was observed. In contrast to vancomycin, teicoplanin induced some lysis of bacteria in hypertonic media, presumably by affecting the integrity of the cell membrane
Quantification of Trovafloxacin in Serum by High-Performance Liquid Chromatography with On-Line Solid-Phase Extraction
No full textSecondo Progetto Artemis Italia (1998): aspetti microbiologici e clinici nelle faringotonsilliti da Streptococcus pyogenes in età pediatrica. 2. Risultati microbiologici
No full textPharmacokinetics of Fluconazole in Normal Volunteers
No full textThe pharmacokinetic profile of fluconazole, after 100 mg i.v. infusion or oral administration of a single 50 mg or 150 mg dose, was investigated in 18 healthy volunteers. At a dose of 100 mg i.v., the half-life (t( 1/2 β)) was 29.73 ± 8.05h. The mean residence time in the plasma was 27.56 ± 5.98 h. The post-distributive volume V(β) = 52.16 ± 9.83 l, approximating that of total bodywater. Renal excretion accounted for 61.64 ± 8.80% of the drug elimination after 48 h, with renal clearance Cl(r) = 12.91 ± 2.83 ml/min. Plasma clearance (Cl(r)) was 21.03 ± 5.07 ml/min. At oral doses of 50 and 150 mg the distribution and elimination of fluconazole resembled that following i.v. infusion. The peak levels in plasma at 2.5 h were 0.93 ± 0.13 and 2.69 ± 0.43 μg/ml, respectively. The large distribution volume, the long half-life and mean residence times, combined with a rapid absorption after oral administration, suggest that fluconazole will be effective at a wide range of body sites
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
Prognostic value of Iron, Nutritional Status Indexes and Acute Phase Protein in Acute Coronary Syndrome.
Full text linkBackground. The relation between the inflammatory status during unstable angina and nutritional parameters has not been well described. We sought to investigate the relation between the acute inflammatory status, as evaluated on the basis of high C-reactive protein (CRP) and serum amyloid A levels and laboratory indexes of iron and nutritional status in patients with unstable angina, and whether the variations in iron levels have a prognostic significance.Methods. The study population consisted of 98 patients admitted to our facility with unstable (group 1: 64 consecutive patients, 52 males, 12 females, mean age 66 ± 10 years) or stable angina(group 2: 34 patients, 30 males, 4 females, mean age 65 ± 9 years). The hemoglobin levels, the erythrocyte mean cell volume, serum iron levels, the increase in transferrin levels, the decrease in the percent transferrin saturation, ferritin levels, the nutritional status, and the CRP and serum amyloid A levels were measured.Results. On the basis of a CRP value > 1 mg/dl, 47 patients with unstable angina and 4 patients with stable angina were identified as having active inflammatory disease. The presence of inflammation was associated with significantly lower mean values of hemoglobin, erythrocyte mean cell volume, serum iron and transferrin levels, and percent transferrin saturation in comparison with patients without inflammation. A significant inverse correlation coefficient between a CRP level > 1 mg/dl and hemoglobin, transferrin levels and percent transferrin saturation was observed: the strongest correlation was with serum iron levels. The relative risk of total cardiac events was significantlygreater in patients with low serum iron levels than in those with high serum iron levels.Conclusions. Patients with acute inflammation present altered iron status indexes. Increased CRP levels and reduced serum iron levels are associated with a worse outcome in patients with unstable angina
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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