1,721,070 research outputs found
Evaluation of witloof chicory for bolting
No full textCITATION: Konig, R. & Combrink, N. J. J. 2002. Evaluation of witloof chicory for bolting. South African Journal of Plant and Soil, 19(1).Please see full-text for abstract.Publisher's versio
Measurement of Frame Dragging with Geodetic Satellites Based on Gravity Field Models from CHAMP, GRACE and Beyond
No full textThe experimental measurement of frame-dragging or the Lense-Thirring (LT) effect based on Satellite Laser Ranging (SLR) observations to the LAGEOS satellites was successfully demonstrated with an accuracy of about 10%. Here we look in detail into the effect of the node drift induced by the time variable part of the C(2,0) term of the gravity field model describing the flattening of the Earth. We demonstrate that errors in C(2,0) can effectively be taken care of by analyzing two satellites for the LT measurement. We also adopt some recent gravity field models in order to independently repeat and extend the LT experiments so far. The gravity field models used for this are derived either partly depending on LAGEOS SLR observations or completely independent from LAGEOS, and based on dedicated gravity field satellite missions like CHAMP, GRACE and GOCE. It turns out that from all the gravity field models tested the claimed accuracy of 10% of the LT measurement can be confirmed
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
Impacts of the LARES and LARES-2 Satellite Missions on the SLR Terrestrial Reference Frame
Full text linkLARES, an Italian satellite launched in 2012, and its successor LARES-2 approved by the Italian Space Agency, aim at the precise measurement of frame dragging predicted by General Relativity and other tests of fundamental physics. Both satellites are equipped with Laser retro-reflectors for Satellite Laser Ranging (SLR). Both satellites are also the most dense particles ever placed in an orbit around the Earth thus being nearly undisturbed by nuisance forces as atmospheric drag or solar radiation pressure. They are, therefore, ideally suited to contribute to the terrestrial reference frame (TRF). At GFZ we have implemented a tool to realistically simulate observations of all four space-geodetic techniques and to generate a TRF from that. Here we augment the LAGEOS based SLR simulation by LARES and LARES-2 simulations. It turns out that LARES and LARES-2, alone or in combination, can not deliver TRFs that meet the quality of the LAGEOS based TRF. However, once the LARES are combined with the LAGEOS satellites the formal errors of the estimated ground station coordinates and velocities and the co-estimated Earth Rotation Parameters are considerably reduced. The improvement is beyond what is expected from error propagation due to the increased number of observations. Also importantly, the improvement concerns in particular origin and scale of the TRF of about 25% w.r.t. the LAGEOS-combined TRF. Furthermore, we find that co-estimation of weekly average range biases for all stations does not change the resulting TRFs in this simulation scenario free of systematic errors
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
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