1,723,026 research outputs found
Latest results from NA50 on J/psi suppression in Pb-Pb collisions
No full textThe main goal of the NA50 experiment is to study the J/psi suppression pattern in PL-rb interactions, at 158 GeV/c per nucleon at the CERN SPS. We present here the results from the 1996 (final) and 1908 (preliminary) data taking periods. They confirm and extend our previous observation that the J/psi is anomalously supressed from peripheral to central collisions. With new event selection procedures and different analysis techniques, we observe that in peripheral collisions the J/psi cross section per nucleon-nucleon collision agrees with the pattern inferred from a wide range of measurements with lighter systems, from pp up to S-U. When the collisions become more central a clear departure from this behaviour is observed. The 1996 data show a sudden drop in the J/psi production yield for E-T values above 40 GeV, where E-T is the neutral transverse electromagnetic energy released in the colision and measured in the EM calorimeter. The 1998 data provide a big improvement in the study of the most central region, where a second change in the pattern becomes visible
The case of the pseudoscalar glueball
No full textGlueballs represent a key requirement of quantum chromodynamics as a non-Abelian field theory. Their search provides one of the strongest motivations for meson spectroscopy. The first glueball candidate was identified in 1980 in the J/Psi radiative decay. Its discovery actually dates back to 1963 and for four decades about 30 experiments, using six different production mechanisms, were dedicated to studying the pseudoscalar states lying in the 1.4-1.5 GeV/c(2) mass region. Today, the presence of two pseudoscalar states and an axial vector can be considered as established (see 2004 edition of the Review of Particle Properties). Assuming that.(1295) is established and the nonet filled, the lower mass pseudoscalar,.(1405), becomes a supernumerary and shows the properties of a non-(q) over barq state. Here, we review the experimental effort related to this long search, which can be considered a sort of paradigm for light-quark spectroscopy
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
A new PCI card for readout in high energy physics experiments
No full textRecently, some high energy physics experiments have started to adopt readout systems based on the PCI architecture. In this context, a new PCI card that can be adapted to several readout schemes has been designed. It contains a 64-MiB(1) local buffer, programmable FPGA logic, a hardware PCI bridge, and can be connected to mezzanine cards. The card is presently used in the NA60 experiment at the CERN SPS for the readout of several detectors. The interfacing to the different front-ends is provided by the mezzanine cards while the readout protocols are implemented in the FPGA. Moreover, it is used as a test readout system for the ALICE experiment muon chambers. This paper describes the card, with particular emphasis on its flexibility and relatively simple development, related to the use of an external PCI bridge. RI Tinoco Mendes, Andre David/D-4314-201
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
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