1,720,963 research outputs found
THE DAMPING OF INTERPLANETARY ALFVENIC FLUCTUATIONS AND THE HEATING OF THE SOLAR-WIND
No full textAstronomy & AstrophysicsSCI(E)140ARTICLEA17-209
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
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
Two-fluid model for heating of the solar corona and acceleration of the solar wind by high-frequency Alfven waves
No full textA model of the solar corona and wind is developed which includes for the first time the heating and acceleration effects of high-frequency Alfven waves in the frequency range between 1 Hz and 1 kHz. The waves are assumed to be generated by the small-scale magnetic activity in the chromospheric network, The wave dissipation near the gyro-frequency, which decreases with increasing solar distance, leads to strong coronal heating. The resulting heating function is different from other artificial hearing functions used in previous model calculations. The associated thermal pressure-gradient force and wave pressure-gradient force together can accelerate the wind to high velocities, such as those observed by Helios and Ulysses. Classical Coulomb heat conduction is also considered and turns out to play a role in shaping the temperature profiles of the heated protons. The time-dependent two-fluid (electrons and protons) model equations and the time-dependent wave-spectrum equation are numerically integrated versus solar distance out to about 0.3 AU. The solutions finally converge and settle on time-stationary profiles which are discussed in detail. The model computations can be made to fit the observed density profiles of a polar coronal hole and polar plume with the sonic point occurring at 2.4 R. and 3.2 R., respectively. The solar wind speeds obtained at 63 R. are 740 km s(-1) and 540 km s(-1); the mass flux is 2.1 and 2.2 x 10(8) cm(-2) s (normalized to 1 AU), respectively. The proton temperature increases from a value of 4 x 10(5) K at the lower boundary to 2 x 10(6) K in the corona near 2 R..Astronomy & AstrophysicsSCI(E)0ARTICLE2363-39117
ON THE NATURE OF COMPRESSIVE FLUCTUATIONS IN THE SOLAR-WIND
No full textA statistical analysis of the amplitudes of the thermal pressure and total pressure of the solar wind and of several related cross correlations between different compressive parameters has been performed with the plasma and magnetic field data obtained by Hellos 1 and 2 in their primary missions. The statistical analysis is based on small-band averages of the relevant spectra over the frequency range (2-5) x 10(-4) Hz, corresponding to hourly timescales. The analysis shows that the theoretical values, given by the relation between the fluctuation of total pressure and density for perpendicular fast magnetoacoustic waves, present an upper limit for the observed amplitudes of the normalized total pressure fluctuations. With decreasing ratio between the fluctuation amplitudes of the total pressure and the density, we found a systematical decrease of the correlation coefficient between density and total pressure and of the correlation coefficient between density and magnetic field magnitude. Decreases of the correlation coefficients between temperature and density and between thermal and magnetic pressure are also found with decreasing ratio of the normalized amplitudes of the fluctuations of the thermal pressure and the temperature. For high-speed wind data the pattern of the data distribution in plots of one correlation coefficient versus the other correlation coefficient skews some systematical changes. Most of these results can be explained qualitatively by a model based on a superposition of small-amplitude perpendicular fast magnetosonic waves and small-amplitude pressure-balanced structures. We have found a class of data points which seem to represent fluctuations dominated by fast magnetosonic waves. In many cases in low-speed wind the correlations between density and total pressure and between temperature and density are both negative, while the correlation between temperature and magnetic magnitude is about zero. The nature of this phenomenon has not yet been clearified. Some possible explanations are suggested. The applicability and relevance of the nearly incompressible magnetohydrodynamics theory for the compressive fluctuations in the inner heliosphere are also discussed.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1994PP43300027&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Astronomy & AstrophysicsSCI(E)70ARTICLEA1121481-215099
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
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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