1,721,413 research outputs found
The helium peculiar star HD 22920
Get PDFContinuing with the spectroscopic analysis of peculiar stars. HD 22920 (22 Eri) was studied. All the elements present in its atmosphere were identified. 22 Eri is not an extreme CP stars and, when compared with other peculiar stars of the same group and with stellar effective temperature, it shares their anomalies and can be included among the helium-weak and the Silicon stars.Asociación Argentina de Astronomí
La complainte d'Hélène dans le Roman de Troie (v. 22920-23011)
No full textCroizy-Naquet Catherine. La complainte d'Hélène dans le Roman de Troie (v. 22920-23011). In: Romania, tome 111 n°441-442, 1990. pp. 75-91
Abundance anomalies in the CP star HD 22920
Get PDFUsing spectroscopic material of 16.9 Å/mm of dispersion, atmospheric parameters and chemical abundances of the CP star HD 22920 are determined. This star has been classified as a B8p Si - λ4200 by some authors while other included it the He- weak group. The atmospheric parameters, Teff=14500 K, log g=3.3 are determined from a "Kiel diagram", obtained from the comparison between observational and theoretical indices of the UBV and uvbyβ photometry and of the profiles of the Balmer lines. With these parameters and the ATLAS 6 program a model atmospheres is generated. Theoretical line profiles are computed using BALMER 6 code, a reasonable agreement with the observed ones is found. Microturbulent velocity is estimated from TiII, FeII and ZrII lines by requiring the abundances to be independent of equivalent widths. The value obtained is ζ = 2.5 km s⁻¹. Helium abundance is estimated from the comparison between observed and theoretical line profiles, it is less than the solar value by a factor of 10. Metallic abundances are calculated with the WIDTH 6 program; it is found that Mg, Si, S and Fe are normal; C, N and O are slightly overabundant while P, Ti, Cr, Mn, Sr, Y, Zr, Pt and Rare Earths are greatly overabundant. These results compared with the prediction of the diffusion theory. HD 22920 belongs definitely to the CP4 group of the CP stars, namely, to the He- weak stars.Asociación Argentina de Astronomí
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
Variations 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
Development of Gasdynamic Probe for Total Temperature Measurement in gases
Get PDFTotal temperature measurement in exhaust stream of air breathing engines like Ramjet, Scramjet and Aircraft afterburners is a challenging task as the temperatures in such engine exhausts are above 2200K. Thermocouples for such high temperature measurement suffer from oxidation and are expensive. Optical method for this application requires high level of expertise and is expensive. Gasdynamic probe is a special type of water cooled probe and can give total temperature of the flow by measuring the flow parameters like total pressure and mass flow through the probe nozzle. The probe is very simple in construction and can be made at a low cost. This paper describes about the development of a Gasdynamic probe and calibration for probe constant for various flow parameter
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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