1,721,023 research outputs found

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Evaluation of zebrafish DNA integrity after exposure to pharmacological agents present in aquatic environments

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    Over the past few years, the increasing and uncontrolled use of pharmaceutical substances in agriculture, fish farming, human health and in veterinary medicine, together with an improper use of out-of-date medicines, has led to a consequent increase in the environmental problems linked to their disposal. In some Italian waste water treatment plants were found furosemide, a diuretic; ranitidine, an antiulcer drug; bezafibrate, a lipid regulator and ibuprofen, a painkiller. The present paper shows, by means of the synergic application of three tests (the Comet Test, the Diffusion Assay and the RAPD-PCR technique), how the DNA of zebrafish can be damaged after exposure to the above mentioned drugs. The data from the Comet Test, the Diffusion Assay and the RAPD-PCR technique were generally in agreement; these results show that all four drugs are genotoxic

    MDMA induces caspase-3 activation in the limbic system but not in striatum

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    Several studies, carried out in chronic (+/-) 3,4- methylenedioxymethamphetamine (MDMA) abusers, have shown memory loss and cognitive impairment, as well as persistent electroencephalographic changes. This suggests that, at least in humans, forebrain areas, including the limbic system, might be altered by MDMA. Consistently, recent experimental evidences suggest that, in rodents, MDMA, besides effects on the basal ganglia, produces alterations in the hippocampus. Therefore, the aim of the present article was to investigate whether treatment with MDMA produces activation of the caspase-3 enzyme, which is part of an enzymatic pathway involved in cell death, within limbic areas (i.e., hippocampus, amygdala, and piriform cortex) and striatum. A marked induction of caspase-3 activity was demonstrated in the amygdala and hippocampus, although MDMA did not affect caspase-3 activity neither in the striatum nor in the frontal cortex. These data indicate that limbic structures possess a high sensitivity to MDMA with respect to the activation of at least one step in the apoptotic pathway. Potential implications and pitfalls of such an experimental observation are reported. © 2006 New York Academy of Sciences

    Variations on the Author

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    “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

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    We 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

    TiO2-NPs and cadmium co-exposure: in vitro assessment of genetic and genomic DNA damage on Dicentrarchus labrax embryonic cells

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    The increased titanium dioxide nanoparticles (TiO2-NPs) spread and their interaction with organic and inorganic pollutants arouses concern for the potential hazards for organisms and environment. This study tested in vitro the genotoxic effects of TiO2-NPs (1 μg/mL) and cadmium (Cd) (0.1 μg/mL) co-exposure using Dicentrarchus labrax embryonic cells (DLEC) as experimental model. The genotoxicity tests (Comet assay, Diffusion Assay and Random Amplification of Polymorphic DNA (RAPD-PCR) were conducted after 3, 24 and 48 hours of exposure to TiO2-NPs and Cd alone and in combination. The results showed that the percentage of DNA damage and apoptotic cells increases following 48 hours TiO2-NPs exposure, while DNA instability was detected for all the times tested. Cd induced genotoxic effects starting from 3 hour-exposure and for all the treatment times. Cd + TiO2-NPs co-exposure did not cause any genomic damage or apoptosis for all the exposure times. The possibility that Cd and TiO2-NPs form aggregates no longer able of penetrating the nucleus and damaging the genetic material is discussed. Graphical abstract: [Figure not available: see fulltext.]
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