1,720,993 research outputs found
A Generalized Density-Based Algorithm for the Spatiotemporal Tracking of Drought Events
Get PDFDrought events evolve simultaneously in space and time; hence, a proper characterization of an event re-quires the tracking of its full spatiotemporal evolution. Here we present a generalized algorithm for the tracking of drought events based on a three-dimensional application of the DBSCAN (density-based spatial clustering of applications with noise) clustering approach. The need for a generalized and flexible algorithm is dictated by the absence of a unanimous consensus on the definition of a drought event, which often depends on the target of the study. The proposed methodology introduces a set of six parameters that control both the spatial and the temporal connectivity between cells under drought conditions, also accounting for the local intensity of the drought itself. The capability of the algorithm to adapt to different drought definitions is tested successfully over a study case in Australia in the period 2017-20 using a set of standardized precipitation index (SPI) data derived from the ERA5 precipitation reanalysis. Insights on the possible range of variability of the model parameters, as well as on their effects on the delineation of drought events, are provided for the case of mete-orological droughts in order to incentivize further applications of the methodology
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
The effects of non-stationarity on SPI for operational drought monitoring in Europe
Get PDFIt is a good practice to follow common guidelines in the computation of Standardized Precipitation Index (SPI) data sets as part of operational drought monitoring systems. In the European Drought Observatory (https://edo.jrc.ec.europa.eu/), reference statistics are computed following the World Meteorological Organization Guidelines on the Calculation of Climate Normals, where a definition of the reference period for monitoring applications is introduced as the most recent 30-year period finishing in a year ending with 0. In this study, the temporal consistency of the SPI time series computed using the fifth-generation European Centre for Medium-range Weather Forecast reanalyses model precipitation data set is tested over Europe to quantify the effect of the transition from one baseline period (1981–2010) to another (1991–2020) and to evaluate the capability of these static baselines to reproduce the behaviour of non-stationary SPIs (nSPIs). The results of the comparison suggest that the threshold commonly used to identify droughts (SPI = −1) is only marginally affected by the change in reference period (mean absolute deviation, MAD = 0.15 ± 0.1) for short-term SPI, whereas larger differences (MAD up to 0.6) can be observed over certain areas (i.e., Southern Italy and Eastern Europe) for longer accumulation periods (i.e., SPI-9 or SPI-12). Examples show that changes in drought classification from extremely dry (SPI < −2) to moderately dry (SPI < −1) are not uncommon, which may lead to misinterpretation by users. Finally, analyses against nSPI highlight an overall good correspondence between stationary and nSPIs, even if both static baselines displayed difficulties in reliably capturing the magnitude of nSPI for the entire 10-year period for which they should be used. In this regard, it has been demonstrated that more spatially uniform results can be achieved with 5-year updates, with a good matching (MAD <0.25) for SPI-1 and an acceptable matching (MAD < 0.50) for SPI-12 over more than 80% of Europe
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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