1,720,985 research outputs found
Does parton saturation at high density explain hadron multiplicities at RHIC?
No full textBaier R, Mueller AH, Schiff D, Son DT. Does parton saturation at high density explain hadron multiplicities at RHIC? PHYSICS LETTERS B. 2002;539(1-2):46-52.We discuss the recent claim that hadron multiplicities measured at RHIC energies are directly described in terms of gluon degrees of freedom fixed from the initial conditions of central heavy ion collisions. The argument is based on the parton saturation scenario expected to be valid at high parton densities and on the assumption of conserved gluon number. Alternatively we conjecture that "bottom-up" equilibration before hadronization. modifies this picture, due to nonconservation of the number of gluons. (C) 2002 Elsevier Science B.V. All rights reserved
Saturation and shadowing in high-energy proton-nucleus dilepton production
No full textBaier R, Mueller AH, Schiff D. Saturation and shadowing in high-energy proton-nucleus dilepton production. Nuclear Physics A. 2004;741:358-380.We discuss the inclusive dilepton cross section for proton (quark)-nucleus collisions at high energies in the very forward rapidity region. Starting from the calculation in the quasi-classical approximation, we include low-x evolution effects in the nucleus and predict leading twist shadowing together with anomalous scaling behaviour. (C) 2004 Elsevier B.V. All rights reserved
"Bottom-up" thermalization in heavy ion collisions
No full textBaier R, Mueller AH, Schiff D, Son DT. "Bottom-up" thermalization in heavy ion collisions. PHYSICS LETTERS B. 2001;502(1-4):51-58.We describe how thermalization occurs in heavy ion collisions in the framework of perturbative QCD. When the saturation scale es is large compared to Lambda (QCD) thermalization takes place during a time of order alpha (-13/5)Q(s)(-1) and the maximal temperature achieved is alpha (2/5) Q(S). (C) 2001 Published by Elsevier Science B.V
Medium-induced radiative energy loss; equivalence between the BDMPS and Zakharov formalisms
No full textBaier R, Dokshitzer YL, Mueller AH, Schiff D. Medium-induced radiative energy loss; equivalence between the BDMPS and Zakharov formalisms. NUCLEAR PHYSICS B. 1998;531(1-3):403-425.We extend the BDMPS formalism for calculating radiative energy loss to the case when the radiated gluon carries a finite fraction of the quark momentum. Some virtual terms, previously overlooked, are now included, The equivalence between the formalism of BDMPS and that of B. Zakharov is explicitly demonstrated, (C) 1998 Published by Elsevier Science B.V
Angular dependence of the radiative gluon spectrum and the energy loss of hard jets in QCD media
No full textBaier R, Dokshitzer YL, Mueller AH, Schiff D. Angular dependence of the radiative gluon spectrum and the energy loss of hard jets in QCD media. PHYSICAL REVIEW C. 1999;60(6): 064902.The induced momentum spectrum of soft gluons radiated from a high energy quark propagating through a QCD medium is derived in the Baier-Dokshitzer-Mueller-Peigne-Schiff formalism. A calorimetric measurement for the medium-dependent energy lost by a jet with opening angle theta(cone) is proposed. The fraction of this energy loss with respect to the integrated one appears to be the relevant observable. It exhibits a universal behavior in terms of the variable theta(cone)(2)L(3)(q) over cap where L is the size of the medium and (q) over cap the transport coefficient. Phenomenological implications for the differences between cold and hot QCD matter are discussed. [S0556-2813(99)06211-1]
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
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
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