1,720,960 research outputs found
INCLUSIVE NEUTRON, PROTON AND DEUTERON ENERGY SPECTRA FROM STOPPED PI- ABSORPTION IN LI-6, BE-9, O-16 AND AL-27
No full textInclusive energy spectra (E ⩾ 20MeV) of neutrons, protons, and deuterons emitted after stopped π− absorption in 6Li, 9Be, 16O and 27Al (neutrons only) were measured. Single-neutron emission rates of the order of 10−2 and 10−3 per stopped pion were obtained for 6Li, 9Be, 16O and for 27Al respectively. The experimental data indicate a predominant contribution of two-nucleon absorption mechanism to the neutron and proton spectra for all the studied nuclei, and presence of direct deuterons from cluster-absorption for 6Li. Values of Rnp are deduced, which are consistent with predictions based on the absorption mechanism by a correlated pair of nucleons with pion rescattering
A counter for the identification and the energy determination of light charged particles and neutrons of energies in the range 20-100 MeV
No full textA large area plastic scintillator counter is described which is used for identifying the mass of light charged particles (p, d, t) of 20–100 MeV with a β-range-energy method, and for measuring their energies as well as that of neutrons of about the same energy by means of the time-of-flight method with a time resolution of 380 ps. The counter is used in an experiment concerning the stopped negative pion absorption in light nuclei. It could be used, however, in other experiments where the identification and the energy measurement of p, d, t, and n in the aforesaid energy range are required
INCLUSIVE NEUTRON AND PROTON ENERGY SPECTRA FOLLOWING THE NEGATIVE PION ABSORPTION AT REST IN C-12
No full textThe results of a measurement of the inclusive energy spectra of the neutrons and protons emitted following the absorption at rest of negative pions on 12C are presented. The spectra have been measured with the time-of-flight method with an overall resolution of 650 psec. From the neutron spectrum the rate of 1.7 × 10−2 neutrons per stopped pion has been deduced for the single-neutron emission reaction 12C(π−, n)11 B. Comparisons are made with calculated spectra and other experimental spectra
The production of monoenergetic fast neutrons of known flux: An improved method to identify the associated particle
No full text
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
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