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Assessing ionospheric activity by long time series of GNSS signals: the search of possible connection with seismicity
Full text linkThe modifications of some atmospheric physical properties prior to a high magnitude earthquake were recently
debated in the frame of the Lithosphere-Atmosphere-Ionosphere (LAI) Coupling model. Among this variety of
phenomena, the ionization of air at the ionospheric levels due to leaking of gases from earth crust through the
analysis of long time series of GNSS (Global Navigation Satellite System) signals was investigated in this work.
Several authors used the dispersive properties of the ionospheric strata towards the GNSS signals to detect possible
ionospheric anomalies over areas affected by earthquakes and some evidences were encountered. However, the
spatial scale and temporal domains over which such disturbances come into evidence is still a controversial item.
Furthermore, the correspondence by chance between ionospheric disturbances and relevant seismic activity is
even more difficult to model whenever the reference time period and spatial extent of investigation are confined.
Problems could also arise from phenomena due to solar activity (now at culmination within the 11 years-long solar
cycle) because such global effects could reduce the ability to detect disturbances at regional or local spatial scale.
In this work, two case studies were investigated. The first one focuses on the M = 6.3 earthquake occurred on April
6, 2009, close to the city of L’Aquila (Abruzzo, Italy). The second concerns the M = 5.9 earthquake occurred on
May 20, 2012, between the cities of Ferrara and Modena (Emilia Romagna, Italy). To investigate possible connections
between the ionospheric activity and seismicity for such events, a five-year (2008-2012) long series of high
resolution ionospheric maps was used. These maps were produced by authors from GNSS data collected by permanent
stations uniformly distributed around the epicenters and allowed to assess the ionospheric activity through
the analysis of the TEC (Total Electron Content). To avoid the influence of solar activity, only nighttime hours
were considered. Moreover, to de?ne the temporal domain of potential ionospheric disturbances and separate local
from global effects, results from local observations were compared with regional TEC series. The whole analysis
shows episodes where anomalies in the ionospheric activity were detected in the vicinity of the mentioned shocks.
However, their statistical significance and the temporal correlation with seismic activity are still controversial
Ionospheric activity and possible connection with seismicity: Contribution from the analysis of long time series of GNSS signals
No full textThe modifications of some atmospheric physical properties prior to a high magnitude earthquake were debated in the frame of the Lithosphere Atmosphere Ionosphere Coupling (LAIC) model. In this work, among the variety of involved phenomena, the ionisation of air at the ionospheric levels triggered by the leaking of gases from the Earth’s crust was investigated through the analysis of GNSS (Global Navigation Satellite System) signals. In particular, the authors analysed a 5 year (2008–2012) long series of GNSS based ionospheric TEC to produce maps over an area surrounding the epicentre of the L’Aquila (Italy, Mw = 6.3) earthquake of April 6th, 2009. The series was used to detect and quantify amplitude
and duration of episodes of ionospheric disturbances by a statistical approach and to discriminate local and global effects on the ionosphere comparing these series with TEC values provided by the analysis of GNSS data from international permanent trackers distributed over a wider region. The study found that during this time interval only three statistically meaningful episodes of ionospheric disturbances were observed. One of them, occurring during the night of 16th of March 2009, anticipated the main shock by 3 weeks and could be connected with the strong earthquake of 6th of April. The other two significant episodes were detected within periods that were not close to the main seismic events and are more likely due to various and global reasons
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
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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