1,721,884 research outputs found
The interaction between the thermosphere and ionosphere at high latitudes
No full textA study has been made of the interaction between the thermosphere and the ionosphere at high latitudes, with particular attention to the value of the 0+-0 collision parameter. The European Incoherent SCATter facility (EISCAT) based at Tromso was used to make tristatic measurements of plasma parameters at F region altitudes while simultaneous independent measurements of the neutral wind were made by a Fabry-Perot Interferometer (FPI). The radar data were used to derive values of the meridional neutral wind. The accuracy of this technique at high latitudes is reduced by the dynamic nature of the auroral ionosphere and the presence of significant vertical winds. The derived winds were compared with the meridional winds measured by the FPI. For each night, the value of the 0+-0 collision parameter was found which produced the best agreement between the two data sets. The precision of the collision frequency obtained in this way depends on the accuracy of the data. The statistical method was critically examined in an attempt to account for the variability in the data sets. The results indicate that the most probable value of the 0+-0 collision parameter is a factor of between 1.2 and 1.7 greater than Banks' theoretical value (Banks, 1966). The contribution of ion drag to the acceleration of the neutral air was also considered. During times of enhanced ion drift, ion drag dominates all other forces acting on the neutral air. A method for determining the neutral ion collision frequency during such an event is described. It was not possible to calculate the neutral ion collision frequency for the two examples in this thesis due to limitations in the radar data.</p
Malva aethiopica, a new name for Lavatera abyssinica (Malvaceae): an endemic species of the Ethiopian Highlands
No full textDavis, Christopher J.S. (2010): Malva aethiopica, a new name for Lavatera abyssinica (Malvaceae): an endemic species of the Ethiopian Highlands. Phytotaxa 13: 56-58, DOI: 10.11646/phytotaxa.13.1.5, URL: http://dx.doi.org/10.11646/phytotaxa.13.1.
FIGURE 1 in Malva aethiopica, a new name for Lavatera abyssinica (Malvaceae): an endemic species of the Ethiopian Highlands
No full textFIGURE 1. Holotype specimen of Malva aethiopica. © Royal Botanic Gardens, Kew.Published as part of Davis, Christopher J.S., 2010, Malva aethiopica, a new name for Lavatera abyssinica (Malvaceae): an endemic species of the Ethiopian Highlands, pp. 56-58 in Phytotaxa 13 on page 57, DOI: 10.11646/phytotaxa.13.1.5, http://zenodo.org/record/477869
EVERY GENUS ONE ALGEBRAICALLY SLICE KNOT IS 1-SOLVABLE
No full textCochran, Orr, and Teichner developed a filtration of the knot concordance group indexed by half integers called the solvable filtration. Its terms are denoted by F-n. It has been shown that F-n/F-n.5 is a very large group for n >= 0. For a generalization to the setting of links the third author showed that F-n.5/Fn+1 is non-trivial. In this paper we provide evidence for knots F-0.5 = F-1. In particular we prove that every genus 1 algebraically slice knot is 1-solvable.
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
Malva aethiopica C. J. S. Davis 2010, nom. nov.
No full text<i>Malva aethiopica</i> C.J.S.Davis, <i>nom. nov.</i> <p> Basionym: <i>Lavatera abyssinica</i> J.Hutchinson & E.A.Bruce in J.B. Gillett (1941:107), <i>non</i> <i>Malva abyssinica</i> A.Braun (= <i>Malva verticillata</i> L.).</p> <p> Type: Ethiopia (‘Abyssinia’). Slopes of Mt Sarerta, 8000 ft, 23 February 1933, <i>J. B. Gillett 5195</i> (holotype K-000240293, isotypes FT, P), Figure 1.</p>Published as part of <i>Davis, Christopher J. S., 2010, Malva aethiopica, a new name for Lavatera abyssinica (Malvaceae): an endemic species of the Ethiopian Highlands, pp. 56-58 in Phytotaxa 13</i> on page 56, DOI: 10.11646/phytotaxa.13.1.5, <a href="http://zenodo.org/record/4778694">http://zenodo.org/record/4778694</a>
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
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