1,721,005 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
Lepton Flavour Violation and K → π ν anti-ν Decays in the Standard Model (Effective Field Theory)
Full text linkA major goal of modern physics is the detection of physics beyond the Standard Model. Promising areas to search for such signals are processes that are either forbidden or highly suppressed within the Standard Model, including Lepton Flavour Violation (LFV) and rare K decays. While LFV is forbidden in the renormalisable Standard Model, the rare K decays K+ → π+νν and KL → π0νν are not, and so precision theoretical predictions are required to distinguish any signal of new physics from the Standard Model background.
We discuss the contribution of the dimension-five lepton number violating Weinberg operator to the running of dimension-six LFV operators in the Standard Model Effective Field Theory. We also consider contributions from a hypothetical second Higgs doublet, which gives rise to Wilson coefficients that cannot all be constrained by small neutrino masses. We then consider bounds on the magnitudes of these Wilson coefficients, by using phenomenological bounds on the low-energy effective theory. Finally, we discuss the calculation of the rare decays K+ → π+νν and KL → π0νν to Next-to-Next-to-Leading Order in QCD. These decays are theoretically very clean, providing a promising arena for the detection of new physics. We discuss in detail the matching of box diagrams in the full Standard Model to diagrams of the effective theory below the weak scale, to O(α2 s). This involves the evaluation of three-loop integrals, and we provide the Wilson coefficients obtained from the matching
Auswirkungen der Flavor- und Higgs-Physik auf Theorien jenseits des Standardmodells
No full textQuantum effects of physics beyond the Standard Model receive strong indirect constraints from precisely measured collider observables. In the conceptual part of this thesis, we apply the generic relations between particle interactions in perturbatively unitary theories to calculate one-loop amplitudes for flavor physics. We provide template results applicable for any model of this class. We also investigate example models that are partly and such that are not perturbatively unitary: the Littlest Higgs model and Randall-Sundrum models. The latter have a unique coupling structure, which we cover exhaustively. We find strong constraints on the Randall-Sundrum models and numerically compare those from flavor, electroweak precision, and Higgs physics by performing detailed parameter scans. We observe interesting correlations between flavor observables, and we find that constraints from Higgs production and decays are already competitive.Quanteneffekte jenseits des Standardmodells sind indirekt, stark durch präzise gemessene Beschleunigerobservablen beschränkt. Im konzeptionellen Teil dieser Arbeit verwenden wir generische Relationen zwischen Teilchenwechselwirkungen perturbativ unitärer Theorien zur Berechnung von Einschleifenamplituden der Flavor-Physik. Wir geben allgemeine Resultate, anwendbar auf alle Modelle dieser Klasse. Wir untersuchen auch Beispielmodelle, welche teilweise, bzw. nicht perturbativ unitär sind: das Littlest Higgs Modell und Randall-Sundrum Modelle. Letztere haben eine besondere Kopplungsstruktur, welche wir eingehend besprechen. Wir finden starke Beschränkungen an Randall-Sundrum Modelle und vergleichen solche aus Flavor-, elektroschwacher Präzisions- und Higgs-Physik numerisch mittels detaillierter Parameterabtastung. Wir finden interessante Korrelationen zwischen Flavor-Observablen und dass Beschränkungen durch Higgs-Produktion und Zerfälle bereits kompetitiv sind
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
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