1,720,988 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
QSARs for the Aquatic Toxicity of Aromatic Aldehydes from Tetrahymena Data
No full textThe aim of the study was to develop quantitative structure-activity relationships (QSARs) for a large group of 77 aromatic aldehydes tested for acute toxicity to the ciliate Tetrahymena pyriformis using mechanistically interpretable descriptors. The resulting QSARs revealed that the 1-octanol/water partition coefficient (log Kow), is the most important descriptor of aldehyde aquatic toxic potency. The model with log Kow was improved by adding electronic descriptor the maximum acceptor superdelocalizability in a molecule – Amax based on calculations with the semi-empirical AM1 model. The two descriptors reflect the two main processes responsible for demonstration of acute aquatic toxicity, namely penetration through cell membranes (log Kow) and interaction with the biomacromolecules (Amax) into the cells. Results showed that generally the studied group of aldehydes could be modeled by this simple two-descriptor approach. However, the group of 2- and/or 4-hydroxylated aldehydes demonstrates enhanced toxicity compared to the other aldehydes. Transformation to quinone-like structures is proposed as the explanation for this enhanced potency. The 2- and/or 4-hydroxylated aldehydes are modeled successfully by [log (1/IGC50) = 0.540 (0.038) log Kow + 8.30 (2.88) Amax – 3.11 (0.92), n = 25, R2 = 0.916, R2CV = 0.896, s = 0.141, F = 120], while the other aldehydes are modeled by the relationship [log (1/IGC50) = 0.583 (0.034) log Kow + 9.80 (2.62) Amax – 4.04 (0.85),
n = 52, R2 = 0.864, R2CV = 0.844, s = 0.203, F = 156], which is similar to the general benzene model.JRC.I.3 - Toxicology and chemical substance
Advances in Bioaccumulation: Reflections from the SETAC Europe 17th Annual Meeting
No full textDifferent pieces of legislation worldwide, and particularly the European Registration Evaluation Authorisation of Chemicals (REACH) program, which entered into force on 1st June 2007, create an increased demand for more reliable information about different toxicological and fate properties, including bioaccumulation. Bioaccumulation has been the focus of dedicated Working Groups to develop guidance for the endpoint under the umbrella of the REACH Implementation Projects (RIP 3.3), and for overall PBT assessment of chemicals (RIP 3.2). The SETAC Advisory Group on Bioaccumulation Assessment (B-SAG) has a proven record of stimulating the incorporation of sound science within regulatory contexts by providing excellent forums for exchange of information and collaboration between scientists from government, industry and academia, and for creating a friendly environment where novel research and young scientists find warm welcome. For the 17th Annual Meeting, the B-SAG organised two oral sessions and two poster corners, which attracted ~60 abstracts and considerable attention at the meeting. The sessions were logically organised around the main themes of in vitro/modelling approaches and lab/field studies, and gave a forum to presenters from two continents, equally eager to share experience and move the science forward. Here we share top lines from the platform presentations.JRC.I.3 - Toxicology and chemical substance
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
Classification of Phthalates According to Their (Q)SAR Predicted Acute Toxicity to Fish: A Case Study.
Full text linkThis report presents the preliminary results from a (Q)SAR investigation of the acute toxicity to fish (fathead minnow) for a dataset of phthalate esters. A chemical set of 341 phthalates was compiled by using different searching engines. Their acute toxicity to fathead minnow was calculated with the ECOSAR and TOPKAT software. A good correlation between the predictions from the two programs was established (r2 = 0.81). The chemicals were classified initially into four groups on a basis of their predicted by ECOSAR LC50 values: 1) no reasons for concern (LC50 > 100 mg/L), 2) harmful (10 mg/L 5). The predictions from TOPKAT (only predictions within the optimum prediction space were considered) correlated relatively well with those from ECOSAR.
There were many high molecular weight phthalate esters in the chemical series, which appeared clearly outside the applicability domain of the ECOSAR models. This fact, as well as the understanding that beyond certain limits of hydrophobicity the toxicity of the organic chemicals decreases as a result of reduced bioconcentration, motivated the development of an algorithm for refinement of acute toxicity predictions of the phthalate esters using the bilinear relationship with log Kow. In addition, water solubility limits were considered.
Long-term toxicity studies were not considered in this study. Transformation (e.g. biodegradability) of the parent compounds was not considered either. This could potentially be important as, theoretically, the transformation of very hydrophobic chemicals (log Kow > 7) or extremely hydrophobic chemicals (log Kow > 8.0) into more hydrophilic degradation/transformation products may increase the acute toxicity to fish.
This case study provides an illustration of how (Q)SAR methods can be used in the development of chemical categories and how (Q)SAR results can be used to perform an initial screening in support of classification and labelling. The results are discussed and interpreted with a view of what constitutes a category, how it can be defined and described, what are its boundaries, and the need to define subcategories that might be useful for deciding on the level of acute toxicological hazard associated with different structural modifications. Due to the preliminary nature of the (Q)SAR models, the results of this study should be regarded as an illustration of the applicability of (Q)SAR methods. The actual model results and rule-based classification scheme will need validation and refinement before they could be considered for regulatory use.JRC.I.3 - Toxicology and chemical substance
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