1,721,126 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
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
Infezioni genitali in una popolazione selezionata di donne in età fertile
No full textINTRODUZIONE. Le infezioni del tratto genitale femminile rappresentano una condizione frequente con un importante impatto economico e sociale. Per alcune di queste, come la vaginosi batterica (BV), specifiche alterazioni nella composizione del microbiota vaginale sono alla base dell’eziopatogenesi. Per altre, invece, come la candidosi e le infezioni da Chlamydia trachomatis (CT) e Neisseria gonorrhoeae (GC), il ruolo che il microbiota svolge nella protezione e nell’evoluzione di tali patologie è ancora da chiarire. Scopo preliminare del presente lavoro è stato quello di valutare la prevalenza delle più significative infezioni genitali in una popolazione selezionata di donne con l’obiettivo finale di studiare la composizione del microbiota vaginale associata ai vari quadri patologici.
MATERIALI E METODI. Da dicembre 2015 a luglio 2016, sono state arruolate nello studio donne in età fertile afferenti all’ambulatorio per le malattie a trasmissione sessuale del Policlinico Sant’Orsola di Bologna. Lo studio ha ricevuto approvazione da parte del Comitato Etico. Criteri di esclusione comprendevano l’etnia non caucasica, un BMI>30, la recente assunzione di antibiotici o l’impiego di ovuli vaginali, la gravidanza, l’uso di farmaci anti-concezionali e la presenza di patologie croniche. Per ogni paziente sono stati raccolti i dati riguardanti l’anamnesi e la presenza di sintomi a livello genitale. Sono stati raccolti inoltre un campione di urina e un tampone vaginale per la diagnosi molecolare di infezioni da CT e GC (Versant CT/GC DNA 1.0; Siemens). Infine, ogni paziente ha eseguito una visita e la raccolta di secrezioni vaginali mediante tampone per la diagnosi di vaginosi batterica (criteri di Amsel), candidosi (positività alla microscopia e/o alla coltura) e vaginite aerobia (aumento della flora batterica aerobia di origine intestinale).
RISULTATI. Un totale di 202 donne, con una età media di 28 anni (range 18-47), sono state arruolate durante il periodo in esame. Di queste 56 (27,7%) hanno ricevuto una diagnosi di candidosi, 30 (14,8%) di infezione da clamidia, 22 (10,9%) di vaginosi batterica, 9 (4,5%) di vaginite aerobia e 3 (1,6%) di gonorrea. Le restanti pazienti presentavano quadri di infezioni miste (6,4%) o sono risultate negative a tutte le indagini (34,1%). Da segnalare che il 50% delle pazienti con infezione da CT era completamente asintomatica. I casi di candidosi erano sostenuti prevalentemente da C. albicans e i sintomi più spesso riportati erano prurito e perdite vaginali. Le pazienti con diagnosi di BV lamentavano più spesso secrezioni con cattivo odore.
CONCLUSIONI.Dal presente studio emerge come candidosi e clamidia rappresentino le infezioni genitale femminili più frequenti in età fertile. La natura asintomatica delle infezioni da CT suggerisce l’implementazione di programmi di screening nel nostro Paese. Lo studio del microbiota vaginale di queste pazienti permetterà di comprendere quali alterazioni possono favorire queste infezioni o esserne la conseguenza
PERFORMANCE DEL WESTERN BLOT COMPARATIVO NELLA DIAGNOSI DI TOXOPLASMOSI CONGENITA IN NEONATI DA MADRI CON SIEROCONVERSIONE TARDIVA
No full textIntroduzione: I nati da madri con infezione tardiva da Toxoplasma gondii sono i più esposti al rischio di toxoplasmosi congenita, con percentuali variabili tra il 25-30% nelle infezioni del secondo trimestre di gravidanza e 65-75% nelle infezioni dell’ultimo trimestre. Per identificare i bambini realmente infetti e procedere solo in questi casi al trattamento terapeutico è fondamentale l’uso di metodiche di laboratorio sensibili e specifiche; la tecnica di Western Blot risponde a tali requisiti. Tra luglio 2009 e luglio 2011 sono state studiate dal punto di vista sierologico 30 coppie madre/figlio; per tali casi il dato era di sieroconversione certa materna oltre la 20a settimana di gestazione. I sieri erano giunti al nostro laboratorio da vari centri neonatali.
Metodi: I sieri sono stati saggiati mediante Enzygnost Toxoplasmosis (Siemens Healthcare Diagnostics) per la ricerca di IgG, IgM e IgA; Vidas Toxo (Biomerieux) per la determinazione di IgM, IgG e avidità anticorpale materna; Western Blot IgG/IgM (LDBio), per una comparazione delle reattività del neonato e della madre, alla nascita, o per una comparazione delle reattività del siero del neonato alla nascita e di quelle nei mesi successivi, entro il terzo mese. Tutti i bambini sono stati inseriti in follow-up, fino all’anno di vita.
Risultati: In tutti questi casi si è riscontrata positività per IgM in WB, in 2 casi si evidenziava anche la presenza di IgG reattive verso antigeni diversi da quelli materni; solo in 3/8 casi le IgM erano positive anche con metodiche classiche, mentre in un altro caso risultavano positive le IgA in immunoenzimatica. In 7 casi la diagnosi è avvenuta entro il primo mese di vita, in un solo caso nel secondo mese.
Conclusioni: Il WB comparativo si conferma il test più affidabile per la diagnosi di toxoplasmosi congenita, permettondo di giungere ad una diagnosi corretta nel minor tempo possibile
Prevalence and antimicrobial resistance of genital Mollicutes in Italy over a two-year period
No full textKnowledge of the prevalence and antimicrobial susceptibility of genital Mollicutes is crucial to offer guidelines for empirical treatments. The aim of this study was to investigate the prevalence and the resistance profile of Mycoplasma hominis (MH) and Ureaplasma urealyticum/Ureaplasma parvum (UU/UP) in genital samples over a two-year period in Bologna, Italy. From January 2015 to December 2016, data on all the subjects providing uro-genital specimens for Mollicutes detection by culture were analyzed. A total of 4660 subjects (84.4% females) were enrolled and an overall Mollicutes prevalence of 30.9% was found. Women turned positive for Mollicutes infection twice as often as men (33.3% vs 17.8%) and the detection rate progressively decreased with increasing age. Ureaplasmas represented the commonest species isolated (overall prevalence: 24.2%), whereas mixed infections (6.5%) and MH single infections (3.9%) were far less common. Ureaplasma species showed significant levels of quinolone resistance, especially to ciprofloxacin (77%), whereas MH strains were non-susceptible to azithromycin and roxithromycin in about 90% of cases. Mollicutes co-infections showed a more severe resistance pattern than single infections. Over time, the resistance rate for azithromycin and roxithromycin increased significantly. Globally, our results revealed that minocycline and doxycycline can still be first-line drugs for Mollicutes treatment
Distribution of genital Mollicutes in the vaginal ecosystem of women with different clinical conditions
No full textUreaplasma urealyticum (UU), Ureaplasma parvum (UP), Mycoplasma hominis (MH) and Mycoplasma genitalium (MG) are the most common Mollicutes of the female genital tract. Although many studies have addressed their possible role in the vaginal ecosystem, many aspects remain to be elucidated. The aim of this study was to evaluate the vaginal presence of ureaplasmas/mycoplasmas in women with different clinical conditions. By means of quantitative PCR assays, the prevalence and load of each Mollicute were assessed in different groups of pre-menopausal women: 'healthy' (n=29), women with bacterial vaginosis (BV) (n=21), patients with Chlamydia trachomatis (CT) infection (n=25) and subjects with vulvo-vaginal candidiasis (VVC) (n=23). Globally, UP was the most prevalent Mollicutes in the vagina (67.3%), followed by MH (14.3%), UU (9.2%) and MG (3.1%). The presence of UU and UP was almost never associated. MH showed a significantly higher prevalence and higher bacterial loads in BV-positive women (P<0.05), whereas patients with CT and VVC were characterized by a Mollicutes pattern similar to healthy women. Mollicutes can be frequently found in the vaginal ecosystem, even in asymptomatic 'healthy' women. Although its presence is not a strict requirement, MH displays a significant role in the pathogenesis of BV
Inhibitory activity of vaginal lactobacilli towards Candida spp.
No full textObjectives. Lactobacilli are the dominant bacteria of healthy vaginal microbiota and their principal function is to maintain an environment that restricts the growth of pathogenic and opportunistic microorganisms, as fungi belonging to the genus Candida. Lactobacilli form a critical line of defence against potential pathogens by lowering the environmental pH through lactic acid production and producing antimicrobial
compounds, or through competitive exclusion. Anyway, the mechanisms underlying antifungal activity against Candida spp. are still not fully understood. In this study, the potential activity against Candida spp. of different strains of vaginal lactobacilli was analysed, focusing on hydrogen peroxide generation, lactic acid production and antimicrobial supernatant fluids activity.
Methods. Seventeen strains of lactobacilli were isolated from vaginal swabs collected from pre-menopausal healthy women. They were taxonomically identified by sequencing the 16S ribosomal RNA gene.
Hydrogen peroxide generation was tested in a semi-quantitative assay on de Man, Rogosa, Sharpe (MRS) agar plates containing tetramethylbenzidine and horseradish peroxidase in anaerobic conditions. Isolates were scored as low, medium and high producing strains. Lactic acid production was measured in cell free supernatants of Lactobacillus cultures by 1H-nuclear magnetic resonance (NMR) analysis. Lactobacillus culture supernatants were tested for their fungistatic or fungicidal activity against 9 Candida strains isolated from vaginal swabs submitted to the Microbiology Laboratory of Sant’Orsola-Malpighi University Hospital of Bologna for routine diagnostic procedures, belonging to C. albicans, C. tropicalis, C. krusei, C. glabrata, C. parapsilosis, and C. lusitaniae species. The in vitro activity of free-cell supernatants was determined by broth microdilution assay in accordance with EUCAST guidelines. To determine if Lactobacillus strains supernatants had a killing effect, samples from wells exhibiting less than 50% of growth were taken and spotted onto SD agar plates. Fungicidal activity was defined as a ≥3 log10 reduction from the starting inoculum.
Results. The Lactobacillus isolates were taxonomically identified as follows: 8 strains of L. crispatus (BC1-BC8), 6 strains of L. gasseri (BC9-BC14), and 3 strains of L. vaginalis (BC15-BC17). All Lactobacillus strains exhibited a good generation of hydrogen peroxide, while the production of lactic acid, even if recorded for all the strains tested, showed concentrations ranging from 4.8 to 50.9 mM. When the anti-fungal activity of Lactobacillus was assessed, L. crispatus supernatants were the most effective, especially versus C. albicans and C. lusitaniae. None of the Lactobacillus strains was able to interfere with C. krusei and C. parapsilosis. Detailed results of fungistatic or fungicidal activity are shown in figure 1.
Conclusion. A major potential application of this study concerns the identification of active Lactobacillus strains that could be administered as probiotics for prophylaxis and/or adjuvant therapy of vulvovaginal candidiasis. Further studies are ongoing to elucidate the mechanisms by which lactobacilli exert their protective functions against Candida
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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