1,720,992 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
The Martian Radiation Environment - Early Mars and Future Measurements with the Radiation Assessment Detector
Full text linkToday, the surface of Mars is an inhospitable environment for any form of life. Due to its thin atmosphere and lack of a global magnetic field, Mars is only weakly protected from charged particles impeding the planet from outer space. In particular, high-energetic galactic cosmic rays can propagate all the way through the atmosphere to the ground. These high-energetic particles create, along with secondary particles produced in the atmosphere and the soil, a surface radiation environment that can pose a possible hazard for life. To estimate this risk, the Radiation Assessment Detector (RAD) will measure the radiation exposure on the surface, as part of the Mars Science Laboratory rover mission, launched in November 2011 and slated to arrive at Mars in August 2012.
Furthermore, there is substantial evidence that, early in the planet's history, conditions on Mars were much more suited for an emergence of life. Especially the Noachian period (~ 4 billion years ago) is deemed as a promising time span. The atmosphere was considerably denser and shielded by a global magnetic field, and large amounts of liquid water could be found on the surface. These factors indicate a radiation environment less dangerous for life. Thus, quantifying the radiation exposure on early Mars is of high importance for the question if life could have ever emerged there.
In this thesis, the influence of higher atmospheric pressure, corresponding to a denser Noachian atmosphere, on the radiation exposure on and beneath the surface is analysed. Furthermore, the influence of the presence of larger volumes of liquid surface water and subsurface water ice on the radiation field are determined. For this, a model was developed that calculates radiation dose rates from computed particle fluxes for these conditions via Monte Carlo methods. In the scope of this work, the existing parameter space of Martian radiation research is expanded by calculating dose rates of a wide set of particle species for a broad range of environmental changes.
As a second main part of this thesis, a model that mirrors an important part of RAD's onboard data processing and reduction was developed. The setup of the electronics' processing logic is explained in detail and it is described how the instrument aims to distinguish measured charged particles onboard in particles penetrating the detector and stopping in it. The model is used to determine necessary cut values for the particle distinction. Additionally, it is shown that the model is able to correctly distinguish penetrating and stopping charged particles in measured calibration data. Furthermore, findings from this research are employed to improve the processing logic.Heutzutage ist die Oberfläche des Mars eine unwirtliche Umgebung für Leben. Aufgrund seiner dünnen Atmosphäre und des Fehlens eines globalen Magnetfelds, ist der Mars nur schlecht vor dem Einfall geladenener Teilchen aus dem Weltall geschützt. Insbesondere hochenergetische galaktische kosmische Strahlung kann sich durch die ganze Atmosphäre bis zum Boden fortbewegen. Diese Strahlung erzeugt, in Kombination mit von ihr in der Atmosphäre und im Boden produzierten Sekundärteilchen, eine Strahlungsumgebung an der Planetenoberfläche, die eine mögliche Gefahr für Leben darstellt. Um diese Gefahr einzuschätzen, wird in der Radiation Assessment Detector (RAD), als Teil der Mars Science Laboratory (MSL) Rover-Mission, diese Strahlenbelastung auf der Marsoberfläche messen. Des Weiteren gibt es deutliche Anzeichen dafür, dass der Mars einmal, früh in seiner Geschichte, sehr viel günstigere Bedingungen für ein potentielles Aufkommen von Leben besaß, insbesondere in der Noachische Periode (vor ~ 4 Milliarden Jahren). Damals war die Atmosphäre beträchtlich dichter und zudem durch ein globales Magnetfeld geschützt. Des Weiteren gab es große Vorkommen an flüssigem Wasser auf der Oberfläche. Diese Umstände deuten an, dass die damalige Strahlungsumgebung weniger gefährlich für Leben gewesen sein könnte. Daher ist es für die Frage, ob sich jemals Leben auf dem Mars entwickeln konnte, von besonderem Interesse, die Strahlenbelastung auf dem frühen Mars abzuschätzen.
In dieser Arbeit wird daher der Einfluss von höheren Atmosphärendrücken, entsprechend einer dichteren Atmosphäre, auf die Strahlenelastung auf und wenig unter der Oberfläche analysiert. Des Weiteren wird ermittlet, welchen Effekt größere Mengen an flüssigem Wasser an der Oberfläche und unterirdischem Wassereis auf das Strahlungsfeld hätten. Hierzu wurde ein Modell entwickelt, mit dem sich die resultierende Strahlendosis aus zunächst berechneten Teilchenflüssen für diese Bedingungen mit Hilfe von Monte Carlo-Methoden ermitteln lassen. Im Rahmen dieser Arbeit konnte der existierende Parameterraum im Bereich der Mars-Strahlungsforschung erweitert werden, da eine große Anzahl an Faktoren für verschiedene Teilchensorten untersucht wurden.
Zusätzlich wurde ein Modell entwickelt, dass einen wichtigen Teil der bordeigenen Datenweiterverarbeitung von RAD nachbildet. Es wird beschrieben, wie die Verarbeitungslogik des Instruments aufgebaut ist, um geladene Teilchen in den Detektor durchdringende und in ihm stoppende Teilchen zu unterscheiden, und wie diese Logik im entwickelten Modell implementiert ist. Es wird erklärt, wie sich mit dem Modell Cut-Werte bestimmen lassen, die für die Teilchenklassifizierung wichtig sind, und wie das Modell hilft die Logik zu verbessern. Es wird außerdem anhand von Kalibrationsdaten gezeigt, dass das entwickelte Modell in der Lage ist, geladene Teilchen korrekt in durchgehende und stoppende Teilchen zu unterscheiden
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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