1,721,128 research outputs found
Emission from the secondary star in the old cataclysmic variable WZ Sagittae
No full textWe present the first detection of the mass donor star in the cataclysmic variable WZ Sagittae. Phase-resolved spectroscopy reveals narrow Balmer emission components from the irradiated secondary star during the 2001 outburst. Its radial velocity curve indicates a systemic velocity of -72+/-3 km s-1 and an apparent velocity amplitude of K'2=493+/-10 km s-1. Doppler tomography reveals a highly asymmetric accretion disk including a significant bright spot contribution 20 days into the outburst. We estimate the apparent primary radial velocity using the Halpha tomogram and find K'1=37+/-5 km s-1. Accounting for the likely systematic errors affecting both K1 and K2 measurements, we conservatively derive 493 km s-1<K2<585 km s-1 and K1<37 km s-1. The measured phase offset between bright spot eclipse and inferior conjunction of the secondary star brackets the allowed mass ratio (q=M2/M1) to lie between 0.040 and 0.075. These constraints imply a white dwarf with M1>0.70 Msolar and a low-mass secondary with M2<0.11 Msolar. A nondegenerate mass donor, implying WZ Sge has not yet evolved through its minimum period, is therefore not ruled out by our observations. This would require an improved estimate of K1
Photometry of the magnetic white dwarf SDSS 121209.31+013627.7
No full textThe results of 27 h of time series photometry of SDSS 121209.31+013627.7 are presented.
The binary period established from spectroscopy is confirmed and refined to 0.061 412 d
(88.43 min). The photometric variations are dominated by a brightening of about 16 mmag,
lasting a little less than half a binary cycle. The amplitude is approximately the same in V, R
and white light. A secondary small brightness increase during each cycle may also be present.
We speculate that SDSS 121209.31+013627.7 may be a polar in a low state.Web of Scienc
The PLATO Multiple Star Working Group (MSWG)
No full textThe PLATO mission is scheduled for launch in December 2026. It is an ESA M-class mission designed to find small planets around bright stars via the transit technique. The light curves it obtains will be wonderful for other science goals, among which is the study of binary and multiple stars. We are creating the Multiple Star Working Group (MSWG) to bring together the community to best exploit this unique opportunity. We will assemble the many science cases, create target lists, and co-ordinate applications for PLATO observations. We include instructions on how to register your interest
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
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