1,721,208 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
Overview of hepatitis B virus mutations and their implications in the management of infection
No full textHepatitis B virus (HBV) affects approximately two billion people worldwide and more than 240 million people in the world are currently chronic carrier that could develop serious complications in the future, like liver cirrhosis and hepatocellular carcinoma. Although an extended HBV immunization program is being carried out since the early ?80s, representing effective preventive measure, leading to a dramatic reduction of HBV hepatitis incidence, globally HBV infection still represents a major public health problem. The HBV virus is a DNA virus belongs to the Hepadnaviridae family. The HBV-DNA is a circular, partial double strand genome. All coding information is on the minus DNA strand and it is organized into four open reading frames. Despite hepatitis B virus is a DNA virus, it has a high mutation rate due to its replicative strategy, that leads to the production of many nonidentical variants at each cycle of replication. In fact, it contains a polymerase without the proofreading activity, and uses an RNA intermediate (pgRNA) during its replication, so error frequencies are comparable to those seen in retroviruses and other RNA viruses rather than in more stable DNA viruses. Due to the low fidelity of the polymerase, the high replication rate and the overlapping reading frames, mutations occur throughout the genome and they have been identified both in the structural and not structural gene. The arise of mutations being to develop of a whole of viral variants called "quasi-species" and the prevalent population, which favors virus replication, was selected by viral fitness, host?s immune pressure and external pressure, i.e. , vaccination or antiviral therapy. Naturally occurring mutations were found both in acute and chronic subjects. In the present review we examine and discuss the most recent available data about HBV genetic variability and its significance
Unexpected high rate of wild-type HIV-1 genotype among inmates failing antiretroviral therapy
No full textPurpose: Combination antiretroviral therapy (ART) has proven to be effective in treating human immunodeficiency virus (HIV) infection. Chronic administration of antiretrovirals presents significant challenges, including the risk of selecting treatment-resistant viral strains that can determine treatment failure and can be transmitted. In many countries, a large proportion of the HlV-infected population goes through the correctional system at least once. Scarce data are available on circulation of resistant HIV strains in correctional facilities. We evaluated the prevalence of antiretroviral resistance among both naïve and treatment-experienced HlV-infected inmates of a correctional institution in Genoa, Italy. Method: The prevalence of antiretroviral resistance among the HlV-infected inmates observed at our institution who underwent genotypic testing from January 2004 to June 2007 was retrospectively reviewed. Results: 45 genotypes from 43 inmates were available. Most of the naïve patients (14/16; 87.5%) showed a wild-type (WT) genotype, as well as most of the ART-experienced patients who had discontinued ART (10/13; 76.9%). A high proportion of WT genotype (6/16; 37.5%) was also observed among the subjects apparently failing HAART. Conclusions: The prevalence of mutated strains in treatment-naïve individuals of the studied cohort is comparable to what is reported in nonimprisoned naïve subjects of our region. The high prevalence of WT genotypes in ART-failing patients makes it likely that they were not taking their treatments, probably to gain legal benefits from their worsening health conditions. Thus, resistance testing can also be considered as an additional tool for assessing adherence to ART for forensic/medicolegal evaluation. However, further and larger studies are necessary to validate it. © 2008 Thomas Land Publishers, Inc
Epidemiology of HBV S-gene mutants in the Liguria Region, Italy: Implications for surveillance and detection of new escape variants.
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