1,721,891 research outputs found
Imaging and background in low energy gamma-ray astronomy
No full textThe current status of low energy gamma-ray astronomy is reviewed and the conclusion drawn that the next generation of low energy gamma-ray telescopes will require high sensitivity, good timing and spectral resolution. High angular resolution imaging capability is also considered essential. The imaging of low energy gamma-rays is hampered by the difficulties encountered in developing high resolution position sensitive detectors. To this end, an improved Rotation Modulation Collimator (RMC) imaging technique, the phoswich multi-pitch RMC, is discussed. This imaging method employs currently available detector and pulse-share discrimination techniques and is capable of producing images with an angular resolution which is comparable with that of the Coded Aperture Mask (CAM) imaging techniques. The imaging property of this new technique is studied in detail. A comparison of three of the main imaging techniques used in low energy gamma-ray astronomy, CAM, Fourier Transform Collimator and RMC, is carried out in terms of both their theoretical performances and simulated imaging of the Galactic Centre region. A realistic assessment of the possible applications of these three techniques to different types of astronomical observations is also given. The atmospheric gamma-ray radiation has been measured by a number of balloon and satellite borne instruments. A model of this radiation is developed based on the data as measured by a Compton telescope designed by the Max-Planck group. Emission spectra, as predicted by the model, are compared with various observed data, both inside and outside the atmosphere. The sources of background noise in low energy gamma-ray telescopes are discussed. A comprehensive model of the background sources is developed and a generalised simulation program is presented which uses a combination of Monte Carlo methods and empirical calculations. Photon, proton and neutron induced backgrounds are all considered as well as the effects of spacecraft and orbit. The model is applied to some existing telescopes and good agreements are obtained, and interpreted as a demonstration of the model validity. Predictions of background level are made for several future missions. A proposed satellite gamma-ray telescope, GRASP, is briefly described in the last chapter.</p
Lei Fan, clarinet
No full textJohannes BrahmsClaude DebussyFrancis PoulencKalmen OppermanAmilcare Ponchiell
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
Impacts of renewable energy regulations on the structure of power generation in China - a critical analysis
No full textAbstract not availableZhen-Yu Zhao, Jian Zuo, Lei-Lei Fan, George Zillant
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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