1,721,009 research outputs found
Simultaneous millimetre-wave and X-ray monitoring of the Seyfert galaxy NGC7469
No full textWe report on daily monitoring of the Seyfert galaxy NGC 7469, around 95 GHz and 143 GHz, with the IRAM 30 m radio telescope, and with the Swift X-Ray and UV/Optical telescopes, over an overlapping period of 45 days. The source was observed on 36 days with IRAM, and the flux density in both mm bands was on average ~10 mJy, but varied by ±50%, and by up to a factor of 2 between days. The present IRAM variability parameters are consistent with earlier CARMA monitoring, which had only 18 data points. The X-ray light curve of NGC 7469 over the same period spans a factor of 5 in flux with small uncertainties. Similar variability in the mm-band and in the X-rays lends support to the notion of both sources originating in the same physical component of the AGN, likely the accretion disk corona. Simultaneous monitoring ineight UV/optical bands shows much less variability than the mm and X-rays, implying this light originates from a different AGN component, likely the accretion disk itself. We use a tentative 14 day lag of the X-ray light curve with respect to the 95 GHz lightcurve to speculate on coronal implications. More precise mm-band measurements of a sample of X-ray-variable AGN are needed, preferably also on time scales of less than a day where X-rays vary dramatically, in order to properly test the physical connection between the two bands
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
Instrumentation pour le radiotélescope de 30 mètres de l'IRAM et observations d'atmosphères planétaires
No full textStability and linearity requirements of instruments used in radioastronomy are especially severe. This thesis describes on one hand the design and construction of a continuum detector fulfilling these requirements. A theoretical study demonstrates that the Schottky diode detector can not provide satisfactory characteristics. The deetector built here, built around tunnel diodes, exhibits a noise close to the limits imposed by fundamental physics. It has nonetheless been kept simple. The following chapter describes the design and construction of the acquisition electronics for a wideband acousto-optic spectrometer and studies its characteristics under realistic operating conditions. It includes the descriptionof a simple method which allows to get rid of the differential linearity errors of analog-to-digital converters. The validation of the spectrograph performance is based on the comparison with two other, identical, filterbank spectrometers. On the scientific side, the reports presents the observations of several objects of the solar system surrounded by an atmosphere and the interpretation of the data in the case of Titan.Les exigences en matière de stabilité et de linéarité des instruments utilisés en radioastronomie sont particulièrement sévères. Ce mémoire présente la conception et la réalisation d'un détecteur continuum adapté à ce cahier des charges. Une étude théorique démontre que le détecteur à diode Schottky ne répond pas à ces besoins. L'instrument finalement réalisé, construit à partir d'une diode tunnel, possède un bruit proche de la limite physique fondamentale. Il reste cependant très simple. Le chapitre suivant est consacré à l'étude et à la réalisation de l'électronique d'acquisition d'un spectrographe acousto-optique à large bande et à l'etude de ses caractéristiques dans des conditions d'utilisation réelles. Il inclut la description d'une méthode simple qui permet de s'affranchir des erreurs de linéarité différentielle du convertisseur analogique-numérique. La validation des caractéristiques du spectrographe s'appuie sur la comparaison avec deux batteries de filtres identiques. Sur le plan scientifique, il présente l'observation d'objets du système solaire entourés d'une atmosphère et l'interprétation des résultats dans le cas de Titan
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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