1,721,025 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Assessment of potential advantages of relevant ions for particle therapy: A model based study
No full textPurpose: Different ion types offer different physical and biological advantages for therapeutic applications. The purpose of this work is to assess the advantages of the most commonly used ions in particle therapy, i.e., carbon (12C), helium (4He), and protons (1H) for different treatment scenarios. Methods: A treatment planning analysis based on idealized target geometries was performed using the treatment planning software TRiP98. For the prediction of the relative biological effectiveness (RBE) that is required for biological optimization in treatment planning the local effect model (LEM IV) was used. To compare the three ion types, the peak-to-entrance ratio (PER) was determined for the physical dose (PERPHYS), the RBE (PERRBE), and the RBE-weighted dose (PERBIO) resulting for different dose-levels, field configurations, and tissue types. Further, the dose contribution to artificial organs at risk (OAR) was assessed and a comparison of the dose distribution for the different ion types was performed for a patient with chordoma of the skull base. Results: The study showed that the advantages of the ions depend on the physical and biological properties and the interplay of both. In the case of protons, the consideration of a variable RBE instead of the clinically applied generic RBE of 1.1 indicates an advantage in terms of an increased PERRBE for the analyzed configurations. Due to the fact that protons show a somewhat better PERPHYS compared to helium and carbon ions whereas helium shows a higher PERRBE compared to protons, both protons and helium ions show a similar RBE-weighted dose distribution. Carbon ions show the largest variation of the PERRBE with tissue type and a benefit for radioresistant tumor types due to their higher LET. Furthermore, in the case of a two-field irradiation, an additional gain in terms of PERBIO is observed when using an orthogonal field configuration for carbon ions as compared to opposing fields. In contrast, for protons, the PERBIO is almost independent on the field configuration. Concerning the artificial lateral OAR, the volume receiving 20% of the prescribed RBE-weighted dose (V20) was reduced by over 35% using helium ions and by over 40% using carbon ions compared to protons. The analysis of the patient plan showed that protons, helium, and carbon ions are similar in terms of target coverage whereas the dose to the surrounding tissue is increasing from carbon ions toward protons. The mean dose to the brain stem can be reduced by more than 55% when using helium ions and by further 25% when using carbon ions instead of protons. Conclusions: The comparison of the PERRBE and PERPHYS of the three ion types suggests a strong dependence of the advantages of the three ions on the dose-level, tissue type, and field configuration. In terms of conformity, i.e., dose to the normal tissue, a clear gain is expected using carbon or helium ions compared to protons
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Physical and biological factors determining the effective proton range
No full textPurpose: Proton radiotherapy is rapidly becoming a standard treatment option for cancer. However, even though experimental data show an increase of the relative biological effectiveness (RBE) with depth, particularly at the distal end of the treatment field, a generic RBE of 1.1 is currently used in proton radiotherapy. This discrepancy might affect the effective penetration depth of the proton beam and thus the dose to the surrounding tissue and organs at risk. The purpose of this study was thus to analyze the impact of a tissue and dose dependent RBE of protons on the effective range of the proton beam in comparison to the range based on a generic RBE of 1.1. Methods: Factors influencing the biologically effective proton range were systematically analyzed by means of treatment planning studies using the Local Effect Model (LEM IV) and the treatment planning software TRiP98. Special emphasis was put on the comparison of passive and active range modulation techniques. Results: Beam energy, tissue type, and dose level significantly affected the biological extension of the treatment field at the distal edge. Up to 4 mm increased penetration depth as compared to the depth based on a constant RBE of 1.1. The extension of the biologically effective range strongly depends on the initial proton energy used for the most distal layer of the field and correlates with the width of the distal penumbra. Thus, the range extension, in general, was more pronounced for passive as compared to active range modulation systems, whereas the maximum RBE was higher for active systems. Conclusions: The analysis showed that the physical characteristics of the proton beam in terms of the width of the distal penumbra have a great impact on the RBE gradient and thus also the biologically effective penetration depth of the beam. © 2013 American Association of Physicists in Medicine
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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