1,722,455 research outputs found
Charmonium production in Pb-Pb interactions at 158 GeV/c per nucleon
No full textThe NA50 collaboration has measured J/psi, psi' and Drell-Yan pair production in Pb-Pb interactions at 158 GeV/c per nucleon at the CERN SPS. Final results from the 1995 run and preliminary ones from the higher statistics 1996 run are presented. An anomalous J/psi suppression (relative to the Drell-Yan process) has been observed with respect to the suppression pattern established in experiments NA38 and NA51 with proton, oxygen and sulfur beams. The 1996 data allow a detailed study of the suppression pattern in the Pb-Pb sample itself, showing a discontinuity around an E-T value (the neutral transverse electromagnetic energy) of 50 GeV. The psi' is also suppressed relative to Drell-Yan, with a pattern very similar to the one observed in S-U collisions. Finally, the pr distributions of dimuons are presented. The average p(T)(2) of the J/psi in Pb-Pb collisions does not increase any more with E-T above 100 GeV
Performance of the ALICE Zero Degree Calorimeters and upgrade strategy
No full textThe Zero Degree Calorimeters (ZDCs) of the ALICE experiment were designed with the twofold purpose of both estimating the centrality in heavy ion collisions by measuring the energy carried away by the spectator nucleons and of measuring the luminosity delivered to the experiment exploiting the high cross sections for neutron emission from electromagnetic dissociation processes. The measurement of centrality has been successfully extended to p-A collisions with the detection of nucleons ejected from the nucleus by the collisions with the projectile proton ("gray" nucleons) and those resulting from de-excitation processes ("black" nucleons). The applications of the detector in triggering and analysis have expanded during the years of operation in the LHC RUN1 and RUN2. These now include both the reaction plane and the longitudinal asymmetry measurements in heavy ion collisions. Moreover the ZDCs are used to reject the parasitic interactions of main bunches with satellite bunches in A-A and p-A collisions and to tag diffractive events in pp collisions. The foreseen operation in RUN3 with the tenfold increase in the luminosity delivered by LHC in heavy ion collisions, together with the continuous acquisition strategy that is being adopted by ALICE, will be challenging for the ZDC readout system. The readout upgrade will be based on FMC digitizers with trigger, timing and charge integration functionality performed through FPGA
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
Measurement of the Λ hyperon lifetime
Full text linkA new, more precise measurement of the Lambda hyperon lifetime is performed using a large data sample of Pb-Pb collisions at root s(NN) = 5.02 TeV with ALICE. The Lambda and (Lambda)_bar hyperons are reconstructed at midrapidity using their two-body weak decay channel Lambda -> p + pi(-) and (Lambda)_bar -> (p )_bar + pi(+). The measured value of the Lambda lifetime is tau(Lambda) = [261.07 +/- 0.37(stat.) +/- 0.72o(syst)] ps. The relative difference between the lifetime of Lambda and (Lambda)_bar, which represents an important test of CPT invariance in the strangeness sector, is also measured. The obtained value (tau(Lambda) - tau((Lambda)_bar))/tau(Lambda) = (0.0013 +/- 0.0028(stat.) +/- 0.0021(syst.) is consistent with zero within the uncertainties. Both measurements of the. hyperon lifetime and of the relative difference between tau(Lambda) and tau((Lambda)_bar) are in agreement with the corresponding world averages of the Particle Data Group and about a factor of three more precise
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
Maria Giovanna Battista di Savoia Nemours: un ritratto in chiaroscuro tra scandali, intrighi di corte e diplomazia
No full textIl saggio racconta le vicende biografiche e politiche di Maria Giovanna Battista di Savoia Nemours, seconda Madama Reale della corte sabauda, in una chiave narrativa accattivante che evidenzia come i pregiudizi sulla sua persona, costruiti ad arte già dai suoi contemporanei, abbiano fortemente condizionato la lettura storica del suo personaggio
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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