1,721,008 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
EUROTRAC-BIATEX. An European program for the investigation of biosphere atmosphere exchange of pollutants
No full textS.11-28The biosphere (i.e. vegetation, soil and microorganisms) acts both, as a sink and source of tropospheric trace constituents. The biosphere has a significant influence on the chemical composition of the atmosphere on a regional and global scale, and thus on several important areas of environmental problems, e.g. acidity of rain and fog, climate, and troposheric ozone formation. Despite of this importance, our knowledge on exchance rates of the individual trace constituents at the biosphere/atmosphere interface is poor. The same applies for the mechanisms involved, which have to be known in order to understand satisfactorily the fate and effects of these trace constituents. However, for modelling tropospheric chemistry processes and for studying emission-effect relaaltions, a better knowledge of biosphere/atmosphere interactions is essential. To attack these problems 27 European research institutions have joint forces to establish the subproject "Biosphere-Atmosphere Exchange of Pollutan ts (BIATEX) "within the frame of EUROTRAC an environmental project of the EUREKA initiative. The aim of the BIATEX-subproject is the quantification of pollutants fluxes between atmosphere and biosphere; the study of the mechanisms within soils and plants which are responsible for the observed exchange, and the provision of regional fluxes on seasonal and annual scales for Europe. In this paper a brief overview of the state of the art regarding Biosphere-Atmosphere exchange of pollutants will be given, followed by the objectives and the planned activities of the BIATEX-program
Contribution of tropospheric SO2 to the stratospheric aerosol layer
No full textS.53-63Measurements of SO2 mixing ratio in the upper troposphere and lower stratosphere have been performed with a sensitive chemiluminescence method which permits the detection of atmospheric SO2 traces below 10 pptv. Results of 9 aircraft ascents over Europe from 1978-1980 are reported. It is shown that the meteorological conditions at the tropopause level have an important influence on the observed SO2 mixing ratio. The weak vertical SO2 gradients in the upper troposphere suggest only a small flux of tropospheric SO2 into the stratosphere. Furthermore, increasing SO2 mixing ratios within the first kilometers of the stratosphere give strong support to a stratospheric SO2 source due to the oxidation of organic sulfur compounds (COS, CS2). SO2 measurements are discussed in the light of improved 1 D models concerning the stratospheric sulfur budget. The results clearly show that tropospheric SO2 is of only minor importance for the non-volcanic formation of the stratospheric aerosol. (IFU
Trockene Deposition von Photooxidantien und deren Vorläufersubstanzen
No full textDie Deposition von Photooxidantien (03, PAN, HNO3, Aldehyde, Peroxide) und deren Vorlaeufersubstanzen (CnHm, NOx, CO) ist elementares Bindeglied zwischen Immission und Wirkung dieser Spurengase. Verschiedene Methoden zur direkten Messung der trockenen Deposition werden in Hinblick auf ihre Anwendbarkeit fuer die Flussmessung dieser Spurengase in komplexem Gelaende diskutiert. Gegenwaertig existieren nur vereinzelte Messdaten der trockenen Deposition von Photooxidantien (Ausnahme: Ozon) und deren Vorlaeufern; unsere Kenntnis ueber entsprechende Depositionsvorgaenge ist aeusserst beschraenkt. Es wird versucht, anhand bekannter Widerstandsmodelle das unterschiedliche Depositionsverhalten einiger der fraglichen Substanzen zu beschreiben und damit eine Moeglichkeit aufzuzeigen, den Eintrag dieser Substanzen in alpine Oekosysteme langfristig und flaechendeckend bestimmen zu koennen. (IFU
The vertical sulfur dioxide distribution at the tropopause level
No full textS.175-189In 1978-1980 nine aircraft flights to an altitude of up to 15 km were made over western Europe. Sulfur dioxide was measured with a sensitive chemiluminescence method consisting of separate sampling and analysis stages and application of a wet chemical filter procedure (detection limit: 8 pptv SO2). The measurements performed in the upper troposphere and lower stratosphere lead to some unexpected results: (a) the meteorological conditions at the tropopause level have an import influence on the observed SO2 mixing ratio; (b) between the 500 mb and the actual tropopause level the SO2 mixing ratio is fount to be smaller than 100 pptv, and weak vertical gradients of SO2, suggest only a small flux of tropospheric SO2 into the stratosphere; (c) increasing SO2 mixing ratios within the first kilometers of the stratospheric give strong support to a stratospheric source of SO2. In the light of improved one-dimensional models considering the vertical distribution of stratospheric sulfur compounds (Crutzen, 1981; Turco et al.1981) it can be shown that the oxidation of organic sulfur compounds (e.g. OCS, CS2) seems to be a stratospheric source of SO2. Furthermore, the flux calculations based on the SO2 mixing ratios measured at the tropopause level indicate that the contribution of tropospheric (man-made) SO2 to the stratospheric aerosol layer is of only minor importance. (IFU)
Troposphärisches Schwefeldioxid - ein Beitrag zur stratossphärischen Aerosolschicht?
No full textS.161-17
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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