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A new map of the world [cartographic material] /
No full textMap of the world.; Rex Nan Kivell Collection Map NK 4593
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
Chandra observations of the planetary nebula IC 4593
No full textThe Advanced CCD Imaging Spectrometer (ACIS-S) camera on board the Chandra X-ray Observatory has been used to discover a hot bubble in the planetary nebula (PN) IC 4593, the most distant PN detected by Chandra so far. The data are used to study the distribution of the X-ray-emitting gas in IC 4593 and to estimate its physical properties. The hot bubble has a radius of similar to 2 arcsec and is found to be confined inside the optically bright innermost cavity of IC 4593. The X-ray emission is mostly consistent with that of an optically thin plasma with temperature kT approximate to 0.15 keV (or T-X approximate to 1.7 x 10(6) K), electron density n(e) approximate to 15 cm(-3) , and intrinsic X-ray luminosity in the 0.3-1.5 keV energy range L-X = 3.4 x 10(30) erg s(-1). A careful analysis of the distribution of hard (E >0.8 keV) photons in IC4593 suggests the presence of X-ray emission from a point source likely associated with its central star (CSPN). If this was the case, its estimated X-ray luminosity would be L-X,(CSPN) = 7 x 10(29) erg s(-1), fulfilling the log(L-X, (CSPN)/L-bol) approximate to -7 relation for self-shocking winds in hot stars. The X-ray detection of the CSPN helps explain the presence of high-ionization species detected in the ultraviolet spectra as predicted by stellar atmosphere models. © 2020 The Author(s).JAT and MAG are supported by the Universidad Nacional Autonoma de Mexico (UNAM) Direccion General de Asuntos del Personal Academico (DGAPA) PAPIIT projects IA100318 and IA100720. MAG acknowledges support from grant PGC2018102184-B-I00, co-funded with FEDER funds. LB and YHC acknowledge support from NASA grant Chandra GO2-13024B. YHC acknowledges the research grant 108-2112-M-001-045 from the Ministry of Science and Technology (MOST) of Taiwan. This work has made extensive use of the NASA's Astrophysics Data System. Based on observations made with the NASA/ESA Hubble Space Telescope, and obtained from the Hubble Legacy Archive, which is a collaboration between the Space Telescope Science Institute (STScI/NASA), the Space Telescope European Coordinating Facility (ST-ECF/ESA) and the Canadian Astronomy Data Centre (CADC/NRC/CSA)
Response to letter regarding "Evidence of natural occurence of the banned antibiotic chloramphenicol in herbs and grass
Get PDFVariations 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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