1,724,060 research outputs found
4FGL J2054.2+6904: A Binary "Redback" Pulsar
No full textThe gamma-ray source 4FGL J2054.2+6904 discovered with Fermi was recently classified as a pulsar candidate. Its possible X-ray and optical counterpart was identified with Swift. Using Zwicky survey data we show that the counterpart is variable in the optical with the period of about 7.5 h. The shape of the light curve is almost sinusoidal with the amplitude of approximate to 0.5m. The spectral energy distribution corresponds to the stellar spectrum with the effective temperature of 5820 +/- 410 K. We also firmly detected the source in X-rays using the SRG/eROSITA all sky survey data. Its X-ray spectrum can be described by a power law with the photon index of about 1.0 and unabsorbed flux approximate to 2 x 10-13 erg/(s cm2) in the 0.5-10 keV range. These results show that 4FGL J2054.2+6904 is a promising candidate to a millisecond pulsar in a close binary system of the "redback" type
California Poll: 6904 -- November 1-9, 1969
No full textThe Field Poll, established in 1945 as The California Poll by Mervin Field, has operated continuously as an independent, non-partisan, media-sponsored public opinion news service. Each year the Field Polls cover a wide range of political and social topics examining California public opinion. Continuing measures are made of voter support for leading political figures vying for major state and federal offices, job ratings of important political figures and reactions to significant political events. Voter awareness, understanding and predispositions of major campaign issues and salient statewide ballot propositions are also tracked over time. For poll 6904 N=923
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
A new redback pulsar candidate 4FGL J2054.2+6904
Get PDFThe Fermi catalogue contains about 2000 unassociated -ray sources.
Some of them were recently identified as pulsars, including so called redbacks
and black widows, which are millisecond pulsars in tight binary systems with
non- and partially-degenerate low-mass stellar companions irradiated by the
pulsar wind. We study a likely optical and X-ray counterpart of the Fermi
source 4FGL J2054.2+6904 proposed earlier as a pulsar candidate. We use
archival optical data as well as Swift/XRT and SRG/eROSITA X-ray data to
clarify its nature. Using Zwicky Transient Facility data in and bands
spanning over 4.7 years, we find a period of 7.5 h. The folded light
curve has a smooth sinusoidal shape with the peak-to-peak amplitude of
0.4 mag. The spectral fit to the optical spectral energy distribution
of the counterpart candidate gives the star radius of 0.50.1 and
temperature of 5500300 K implying a G2--G9-type star. Its X-ray spectrum
is well fitted by an absorbed power law with the photon index of 1.00.3
and unabsorbed flux of erg s cm. All
the properties of 4FGL J2054.26904 and its presumed counterpart suggest that
it is a member of the redback family.Comment: Accepted for publication in MNRAS, 6 pages, 6 figure
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
A new combination in Chionoloma Dix. (Musci, Pottiaceae)
No full textAfter publication of the partial revision of Symblepharis Broth., Asian material (Sollman 2000), I came to realize that a new combination in Chionoloma Dix. is necessary; see especially mewnzel (1992)
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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