1,721,131 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
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
Portrait of a colour octet
Full text linkNew colour octets stand out among the new physics proposals to explain the anomalous forward-backward asymmetry measured in production by the CDF experiment at the Tevatron. We perform a fit to observables at the Tevatron and the LHC, including total cross sections, various asymmetries and the top polarisation and spin correlations, to find the most likely parameters of a light colour octet to be consistent with data. In particular, an octet coupling only to right-handed quarks gives a good fit to all measurements. The implications from the general fit are drawn in terms of predictions for top polarisation observables whose measurements are yet not very precise, and observables which simply have not been measured.New colour octets stand out among the new physics proposals to explain the anomalous forward-backward asymmetry measured in production by the CDF experiment at the Tevatron. We perform a fit to observables at the Tevatron and the LHC, including total cross sections, various asymmetries and the top polarisation and spin correlations, to find the most likely parameters of a light colour octet to be consistent with data. In particular, an octet coupling only to right-handed quarks gives a good fit to all measurements. The implications from the general fit are drawn in terms of predictions for top polarisation observables whose measurements are yet not very precise, and observables which simply have not been measured
CP violation in selectron cascade decays e˜L→eχ˜20→eχ˜10μ+μ−
No full textAbstractSelectron decays constitute a source of 100% polarised neutralinos, whose helicity is fixed by the charge and “chirality” of the decaying selectron. In SUSY scenarios where the second neutralino χ˜20 has three-body decays, the cascade decay e˜L→eχ˜20→eχ˜10μ+μ− provides a clean place to study CP violation in the neutralino sector, through the analysis of CP-violating asymmetries involving the χ˜20 spin s→ and the momenta of the two muons. We show that a CP-violating asymmetry in the triple product s→⋅(p→μ−×p→μ+) could be observable at a 800 GeV linear collider provided the gaugino mass M1 has a large phase at the electroweak scale
Tripartite entanglement in H →zZ,WW decays
No full textThe decays of the Higgs boson produce a state in which the spins of the decay products and the orbital angular momentum (L) are highly entangled. We obtain the tripartite density operator, as well as reduced operators, for the decay into two weak bosons. For H→ZZ in the four-lepton final state we also estimate the statistical sensitivity at the Large Hadron Collider and future upgrades, using a binned method to reconstruct the density operators from distributions. With the expected Run 3 data, establishing genuine tripartite entanglement would be possible beyond the 5σ level. The violation of Bell inequalities involving the spins of the two weak bosons could also be established beyond the 5σ level. © 2024 authors. Published by the American Physical Society.This work has been supported by the Spanish Research
Agency (Agencia Estatal de Investigación) through
Projects No. PID2019–110058GB-C21, No. PID2022-
142545NB-C21, and No. CEX2020-001007-S funded by
MCIN/AEI/10.13039/501100011033, and by Fundação
para a Ciência e a Tecnologia (FCT, Portugal) through
Project No. CERN/FIS-PAR/0019/2021.Peer reviewe
Toponium hunter’s guide
No full textWe address the discovery and characterization of toponium production at the Large Hadron Collider. In the dilepton decay mode, multivariate analyses of spin and color observables could provide evidence that an excess of events present near the tt¯ threshold corresponds to a spin-zero color singlet. The semileptonic decay mode may also exhibit an excess near threshold, but is not expected to play any role in the toponium characterization.We address the discovery and characterisation of toponium production at the Large Hadron Collider. In the dilepton decay mode, multivariate analyses of spin and colour observables could provide evidence that an excess of events present near the threshold corresponds to a spin-zero colour singlet. The semileptonic decay mode may also exhibit an excess near threshold, but is not expected to play any role in the toponium characterisation
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