1,721,055 research outputs found
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
Thermal and Nonthermal Emission from the Nearby Galaxy M33 : A Multi-Scale Study of Infrared and Radio Emission
Full text linkA multi-wavelength study of radio and IR emission from the nearby galaxy M33 is presented. We focus on three main topics: 1) energy sources of IR emission and its correlation with radio continuum emission at different spatial scales, 2) separation of thermal and nonthermal components of the radio continuum emission without assuming a constant nonthermal spectral index, and 3) distribution of the linearly polarized emission and magnetic fields in M33. Highly resolved and sensitive Spitzer MIPS images of M33 at 24, 70, and 160μm enabled us to study the morphology of different dust components and their role in attenuation of the Hα emission from this galaxy. Radio continuum observations with the VLA and the 100-m Effelsberg telescope led to high sensitive maps of total and linearly polarized radio continuum emission at low (1.42 GHz) and high frequencies (8.35 GHz). A 2D-wavelet transformation was used to find dominant scales of emitting structures, separate the diffuse emission components from compact sources, and compare IR emitting structures to those at radio and Hα wavelengths. We found that the IR emission is powered predominantly by young O/B stars, specifically at 24μm and 70μm. At least up to scales of 0.8 kpc, the cold dust (emitting at 160µm) is also effectively heated by UV photons from massive ionizing stars, however, the average radiation field also contributes to heating the cold dust at larger scales. At scales smaller than 4 kpc, emission from both the warm and the cold dust show better correlation with the thermal radio than with the nonthermal radio emission, indicating a more important role of UV photons from O/B stars than of cosmic ray electrons in heating the dust at these scales. Interestingly, there is a characteristic scale range where the nonthermal radio-IR correlation is maximum: scales of giant star-forming regions, spiral arms and the central extended region of M33, 0.8-2 kpc, indicating regions with high-density cosmic rays and/or stronger (turbulent) magnetic field. We developed a new thermal/nonthermal separation method based on a de-reddened Hα map as a template for the thermal radio emission. For the first time, we derived a map of the nonthermal spectral index in a galaxy by means of this method, directly indicating energy loss of cosmic ray electrons when diffusing away from their origins in star-forming regions towards interarm regions and the outer parts of the galaxy. Furthermore, this energy loss is more significant at 8.35 GHz than at 1.42 GHz. Assuming equipartition between the magnetic field and cosmic ray electrons, we obtained the scale length of the cosmic ray electrons and of the magnetic field of about 12 kpc and 24 kpc, respectively. The large-scale magnetic field exhibits a well ordered spiral structure with almost the same orientation as that of the optical spiral arms. There is a north-south asymmetry in the received polarized emission that is frequency-dependent and most probably caused by Faraday depolarization effects. About 10% of the nonthermal emission from M33 at 8.35 GHz is polarized, mostly due to the strong polarized emission from a magnetic arm in the north-west of the galaxy. The average total and regular magnetic field strengths in M33 are about 6.4μG and 2.5μG, respectively
Jets from Spinning Black Holes in Active Galactic Nuclei
Full text linkRelativistic jets are highly collimated plasma outflows that can be present in extragalactic radio sources, which are associated with active galactic nuclei (AGN). Observations give strong support for the idea that a supermassive black hole, surrounded by an accretion disk, is harbored in the center of an AGN. The jet power can be generally provided by the accretion disk, by the black hole rotation, or both. Such powerful jets can also be sites of the origin of ultra-high-energy cosmic rays (UHECRs). The main aim of the research in this thesis was to improve the current understanding of the mechanisms of jet formation from rapidly-spinning black holes in the framework of General Relativity and General Relativistic Magnetohydrodynamics, as well as the production of UHECRs in AGN jets. The work contains (i) a "Magnetic Connection Model for Launching Relativistic Jets from Kerr Black Holes", (ii) a model for "Ultra-High-Energy Cosmic Ray Contribution from the Spin-Down Power of Black Holes," and (iii) "General Relativistic Magnetohydrodynamic Simulation of Jet Formation from Kerr Black Holes.
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