1,721,118 research outputs found
RECALIBRATION OF THE H(-0.5)-MAGNITUDES OF SPIRAL GALAXIES
No full textThe H-magnitude aperture data published by the Aaronson et al. collaboration over a 10 year period is collected into a homogeneous data set of 1731 observations of 665 galaxies. Ninety-six percent of these galaxies have isophotal diameters and axial ratios determined by the Third Reference Cataloque of Bright Galaxies (RC3; de Vaucouleurs et al. 1991), the most self-consistent set of optical data currently available. The precepts governing the optical data in the RC3 are systematically different from those of the Second Reference Catalogue (de Vaucouleurs, de Vaucouleurs, & Corwin 1976), which were used by Aaronson et al. for their original analyses of galaxy peculiar motions. This in turn leads to systematic differences in growth curves and fiducial H-magnitudes, prompting the present recalibration of the near-infrared Tully-Fisher relationship. New optically normalized H-magnitude growth curves are defined for galaxies of types SO to Im, from which new values of fiducial H-magnitudes, Hg-0.5, are measured for the 665 galaxies. A series of internal tests show that these four standard growth curves are defined to an accuracy of 0.05 mag over the interval -1.5 less than or equal to log (A/Dg) less than or equal to -0.2. Comparisons with the Aaronson et al. values of diameters, axial ratios, and fiducial H-magnitudes show the expected differences, given the different definitions of these parameters. The values of Hg-0.5 are assigned quality indices: a quality value of 1 indicates an accuracy of less than 0.2 mag, quality 2 indicates an accuracy of 0.2-0.35 mag, and quality 3 indicates an accuracy of more than 0.35 mag. Revised values of corrected H I velocity widths are also given, based on the new set of axial ratios defiend by the RC3
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
HUBBLE-SPACE-TELESCOPE FAR-ULTRAVIOLET IMAGING OF M31, M32, AMD NGC-205
No full textHubble Space Telescope Faint Object Camera (FOG) f/48 images of M31, M32, and NGC 205 (held of view 23'' x 23'' with 0''.45 pixel size) are analyzed as observed through the combined UV filters F150W and F130LP. The absolute calibration of the data and the internal disagreement between observed and expected count rates in the UV region lead us to suggest that the filter combination F150W + F130LP suffers from a 5 times degraded UV sensitivity. A corrected efficiency curve is constructed using the UV/optical spectral energy distributions of these three galaxies, which is consistent with all of the data analyzed here. Eighty-one individual stars are detected in M31, 10 stars in M32, and 78 stars in NGC 205. Comparisons with other UV images and optical images indicates that these stars are hot, UV-bright stars, even though our corrected efficiency curve suggests that flux from 1200-2450 Angstrom contributes only 7% of the counts in M32, 19% in M31, and 60% in NGC 205. The morphology of the galaxies in our images is consistent with existing data. The complex nucleus of M31 as seen by Lauer et al. (1993) is confirmed; M32 has a generally smooth appearance and NGC 205 is dominated by a UV-bright, somewhat resolved nucleus. Analysis of these data is done through the new, extensive stellar isochrones of Bertelli et al. (1994) and the population synthesis models of Bressan, Chiosi, and Fagotto (1994). This analysis shows that high-metal stars (Z > 0.05) evolve into UV-bright stars (P-EAGB, H-HB, and AGB-manque stars) that are less luminous and cooler but are significantly longer lived than the P-AGB stars produced by stars with Z < 0.05. Moreover, the proportion of P-EAGB, H-HB, and AGB-manque stars is also a function of age, with order stars of fixed mean metallicity having a higher proportion than younger stars. Hence, with either metallicity or age differences as an interpretation of the line-strength luminosity correlation for ellipticals, the high-metallicity ''tail'' of the stellar content of a galaxy can produce far-UV flux in much greater proportion than its actual proportion of galaxy mass. Separately, the UV-brightest stars in these stellar populations will be the shorter lived P-AGB stars and, hence, more readily observed in imaging observations such as ours. The resulting model of the sources of far-UV flux is inherently composite, with the total UV flux from a stellar population both rapidly increasing and changing its mean spectrum with increasing mean metallicity (or mean age). This model is consistent with five pieces of observational evidence: (1) the correlation of UV-optical color with metallicity documented by Burstein et al. (1988) for early-type galaxies, (2) the low absolute UV flux from M32, (3) the apparent composite nature of UV flux from giant E's and the bulge of M31, as seen by the Hopkins Ultraviolet Telescope (HUT) spectral observations of Ferguson and Davidsen (1993), (4) our FOC observations of P-AGB stars that contribute a minority UV flux in M31, and (5) the possibility that ellipticals might have correlations of either age or metallicity with absolute luminosity (Faber, Gonzalez, and Worthey 1992)
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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