1,720,963 research outputs found
Genotoxicity biomarkers in Mytilus galloprovincialis: wild versus caged mussels
No full textA biomonitoring programme of wild and caged mussels (Mytilus galloprovincialis) was carried out at four selected sites along the Ligurian coast: Cornigliano, Voltri, Zinola, and Sanremo (Italy). Mussels of a very narrow size range were left in situ for 30 days. Adult specimen of mussels from natural substrates were collected in the same areas. Animals from a mussel farm located in La Spezia were used as controls. Micronucleus frequency and DNA single strand breaks, evaluated by alkaline elution, were used as biomarkers of genotoxicity. Mussels were also analyzed for polycyclic aromatic hydrocarbons (PAH) and heavy metals (Hg and Cd). Different gradients of PAH and metal concentrations were detected in tissues of mussels from different samplings sites. A weak correlation was found between single strand breaks and PAH content while MN frequency correlated with Hg concentration (r = 0.28, P < 0.002). A clear distinction between the sites, allowing classification along a pollution gradient (Sanremo < Zinola < Voltri < Cornigliano) was demonstrated by the analysis of genotoxicity parameters. The obtained results suggested that the micronucleus assay compared with DNA damage determination by alkaline elution allow to better discriminate the selected sites. DNA damage expressed as constant of elution (k ml(-1) x 10(3)) ranges from 30 +/- 9.6 to 89.60 +/- 40.10, and micronuclei frequency from 1.78 +/- 1.04 to 24.4 +/- 12.9, in control animals and in mussels from the most polluted site, respectively. Wild mussels accumulated significant concentrations of chemicals and showed a higher induction of chromosomal damage than caged mussels, expressed as micronuclei frequency. Caged mussels showed higher level of DNA damage than wild mussels, probably as a result of recent exposure. DNA damage was higher in September than in May, as opposed to micronuclei frequency being higher in May than in September. Endogenous and exogenous factors, such as change of pollutant input levels or compositions, could be considered the cause of such variability
Genotoxicity biomarkers in the assessment of heavy metal effects in mussels: Experimental studies
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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
The micronucleus assay as a biological dosimeter in hospital workers exposed to low doses of ionizing radiation.
No full textThe health risk associated with low levels of ionizing radiation is still a matter of debate. A number of factors, such as non-target effects, adaptive responses and low-dose hypersensitivity, affect the long-term outcome of low-dose exposures. Cytogenetic bio-dosimetry provides a measure of the absorbed dose, taking into account the individual radiation sensitivity. The aim of the present study is to evaluate the value of the micronucleus (MN) test as a bio-dosimeter in hospital workers exposed to low doses of ionizing radiation. Blood samples were obtained from 30 subjects selected among workers exposed to X- and gamma-radiation, and 30 controls matched for sex, age and smoking from the same hospital. Micronucleus frequencies were analyzed by use of the cytokinesis-block method. The MN frequency was compared among the groups considering the confounding factors and the length of employment. No increase in the number of bi-nucleated cells with MN (BNMN), but a significant increase in the number of mono-nucleated cells with micronuclei (MOMN) was observed in exposed subjects compared with the controls. The relationship between MN frequency and accumulated dose (mSv) was evaluated. The length of employment did not affect the extent of MN frequency, but an increase of BNMN and MOMN cells was observed based on the accumulated radiation dose. Our study shows the sensitivity of the MN test in the detection of cytogenetic effects of cumulative exposure levels, suggesting the potential usefulness of this assay in providing a biological index in medical surveillance programs
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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