1,723,153 research outputs found
A rare outburst from the stealthy BeXRB system Swift J0549.7-6812
No full textSwift J0549.7 -6812 is a Be/X-ray binary system (BeXRB) in the Large Magellanic Cloud (LMC) exhibiting an ~6 s pulse period. Like many such systems, the variable X-ray emission is believed to be driven by the underlying behaviour of the mass donor Be star. In this paper, we report on X-ray observations of the brightest known outburst from this system, which reached a luminosity of ~8 × 1037 erg s-1. These observations are supported by contemporaneous optical photometric observations, the first reported optical spectrum, as well as several years of historical data from Optical Gravitational Lens Explorer (OGLE) and Gaia . The latter strongly suggest a binary period of 46.1 d. All the observational data indicate that Swift J0549.7 -6812 is a system that spends the vast majority of its time in X-ray quiescence, or even switched off completely. This suggests that occasional observations may easily miss it, and many similar systems, and thereby underestimate the massive star evolution numbers for the LMC
A rare outburst from the stealthy BeXRB system Swift J0549.7-6812
No full textSwift J0549.7 -6812 is a Be/X-ray binary system (BeXRB) in the Large Magellanic Cloud (LMC) exhibiting an ~6 s pulse period. Like many such systems, the variable X-ray emission is believed to be driven by the underlying behaviour of the mass donor Be star. In this paper, we report on X-ray observations of the brightest known outburst from this system, which reached a luminosity of ~8 × 1037 erg s-1. These observations are supported by contemporaneous optical photometric observations, the first reported optical spectrum, as well as several years of historical data from Optical Gravitational Lens Explorer (OGLE) and Gaia . The latter strongly suggest a binary period of 46.1 d. All the observational data indicate that Swift J0549.7 -6812 is a system that spends the vast majority of its time in X-ray quiescence, or even switched off completely. This suggests that occasional observations may easily miss it, and many similar systems, and thereby underestimate the massive star evolution numbers for the LMC
Fragmenta chorologica occidentalia, Lichenes, 6812-6856
No full text[Inicio] 6812. Arthonia cinnabarina (DC.) Wallr.
ESP, *CANTABRIA: Garganta del Urdón, camino de
Tresviso, 30TUN6791, 200-250 m, en Corylus
avellana, 10-V-1992, J. Etayo, M.E. López de Silanes, G. Paz-Bermúdez & A. Terrón, SANT-Lich.
9593.
6813. Bacidia arceutina (Ach.) Arnold
ESP, * ASTURIAS: Trescares, orilla del río Cares,
30TUN6298, 80-90 m, en Ulmus sp., 9-V-1992,
/. Etayo, M£. López de Silanes, G. Paz-Bermúdez
& A. Terrón, SANT-Lich. 9589. Zona baja de la
Sierra del Sueve, arroyo de la Corteguera, 30T
UP20, 200 m, en Alnus glutinosa, 9-V-1992,
/. Etayo, M.E. López de Silanes, G. Paz-Bermúdez
& A. Terrón, SANT-Lich. 9262, Herb. Etayo 0799. [...
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
No full textWe 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
- …
