1,720,961 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
Optimizing a Calorimetry Chamber for the RF Characterization of Superconductors
Get PDFIn this thesis an optimized calorimetry chamber is developed, providing at and easy mountable
samples. Furthermore, it enables exchangeability of samples between the resonators at HZB and
CERN.
The thesis is structured as follows: First, a short introduction into SRF is given. The focus
is on the surface resistance and a theoretical derivation is given using the two-fluid model of
superconductivity. Subsequently, the Quadrupole Resonator is introduced. The RF design is
presented and the calorimetric measurement principle, enabling precision measurements of the
RF surface resistance, is derived. In chapter 4 the impact of a demountable sample on the RF
inside the resonator is investigated and boundary conditions concerning the technical realization
are extracted. Afterwards, a prototype made out of aluminum is studied (chapter 5) and the
experience gained there is used to define a final design (chapter 6). The new design could already
be used for a first measurement at CERN with the results given in chapter 7.
At the end of the thesis a summary of the obtained results is given. Observed difficulties are
discussed together with an outlook towards possible future steps using the optimized calorimetry
chamber.
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
Characterization of Nb3Sn and Multilayer Thin Films for SRF Applications
No full textBasic R amp;D on materials for superconducting radio frequency SRF applications requires RF measurements on samples with high resolution. The Quadrupole Resonator QPR at Helmholtz Zentrum Berlin is a dedicated test cavity, enabling RF characterization of samples in a wide parameter space of temperature and RF field strength at three frequencies. Thereby, the instrument covers typical real life accelerator conditions without being limited to it. Within the scope of this thesis, the QPR measurement capabilities were continuously expanded and improved, allowing calorimetric measurements of RF surface resistance at all three operating frequencies. Furthermore, magnetic penetration depth, critical temperature Tc and the RF critical field can be studied. From those directly measured values, superconducting and normal conducting quantities such as DC critical fields, Ginzburg Landau parameter, mean free path and normal state resistivity can be derived, yielding a multi parameter characterization of the investigated sample. In this work, two superconducting coatings were characterized One single layer of Nb3Sn and a NbTiN on Nb multilayer structure. Nb3Sn is one of the most promising alternative materials to niobium and already showed high quality factors in coated research cavities. The sample investigated here underscores the potential of this high Tc material for low surface resistance. Ultimately, this could enable low loss continuous wave particle accelerators. However the SRF performance failed to reach theoretical values, presumably due to off stoichiometric areas that were subsequently identified using surface analysis. Furthermore, the RF quench field measurement indicated practical difficulties in reaching the superheating critical field of Nb3Sn with the current coating process. Multilayer structures of superconducting thin films are expected to increase the superheating critical field of a bulk superconductor, corresponding to higher maximum achievable accelerating gradients. With the second sample characterized in this work, the theoretical descriptions of magnetic penetration depth and superheating field for multilayer structures can be confirmed. The observation of non monotonic surface resistance as a function of temperature reveals additional contributions that are not included in current theories and opens a promising field for future studie
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
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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