1,721,153 research outputs found
The European radio network (INFREP) for studying earthquake precursors: status and preliminary results obtained on the occasion of the Dodecanese islands earthquakes (January 30, 2020; MW=5.6 and MW=5.7)
No full textThe paper describes the current status of the European radio network INFREP developed for studying earthquake precursors and reports the preliminary results obtained on the occasion of the Dodecanese islands earthquakes (MW=5.6 and MW=5.7) occurred on January 30, 2020. Information for the registration of users interested to the visualization of the trends and to download of the data acquired by the VLF/LF receivers of the INFREP network are also provided
The European VLF/LF radio network: current status
No full textFor several years researches about correlation between seismicity and disturbances
in radio broadcasting are being carried out: in particular, the Japanese Pacific VLF radio
network and the European VLF–LF radio network have been developed during the last
years. The European network has been developed starting from two LF receivers located in
central Italy in 1996. Up to now, 11 receivers of a new type, able to sample the VLF and LF
intensity of ten radio signals, are being into operation in different European countries. The
daily updating of data is effective and the data bank is located at the Department of Physics
of the University of Bari (Italy) which is the central node of the network. In order to discover
anomalies, the software able to carry out automatically a daily data analysis by the Wavelet
spectra method has been planned and realized. At the moment, the software operates on four
signals (two LF and two VLF) collected by one of the receiver located in Italy. If the anomaly
is particularly strong a warning system gives an advise on the work station into operation
in the central node of the Network. In any case, before assuming an anomaly as a seismic
anomaly, geomagnetic and meteorological data must be checked as well as any possible
instrumental malfunction. At present these controls are carried out only discontinuously by
the researchers of the Bari Team
Geochemical and VLF-LF radio precursors of strong earthquakes: a review.
No full textResults obtained by the authors during many years of observations related to hydro-geochemical parameters and LF/VLF radio signals are presented. Firstly, the analysis carried out for more than ten years on the ions and gases content data collected from the groundwater of six deep wells and two natural springs in the southern area of the Kamchatka peninsula (Russia) is reported. The following general statements can be made: a) middle-term precursors could be observed during the preparatory phase of earthquakes with M (magnitude) around 7.0 and larger, located at distances less than 100-150 km from the measurement site; b) for larger distances, short-term precursors could be observed on the occasion of large but very shallow earthquakes and probably, in such cases, the dissolved gases are parameters more sensitive than the ions; c) on the occasion of large earthquakes, post-seismic effects can be observed; d) all the previous effects do not appear at each measurement site of a hydro-geochemical network and it means that they are related to some local phenomenology connected with the underground structural situation; e) long-term (some years) precursors could appear at each measurement site of a hydro-geochemical network. In such a case, probably a great increase of stress must be claimed and, as precursors, the variations could be related to more than only one large earthquake. The mentioned results were obtained in Kamchatka, that is an active margin where the Pacific plate subducts beneath the North American and Eurasia plate. In any case, they should represent the general behavior of the hydro-geochemical parameters in connection with the seismic activity. As concerns the LF and VLF radio signals, the results are reported obtained with the VLF and LF receivers located in Bari (south Italy) and in Assergi (central Italy), respectively. The following general statements can be made: a) a good possibility exists that the earthquakes with M≥4.3 can produce some decrease in the intensity of the VLF radio signals, when the path is near enough to the epicenters. The decreases can represent a pre-seismic or a post-seismic effect. B) the LF radio signals can supply two different types of information related to the ground wave and to the sky wave. Particularly, anomalies appearing mainly in the ground wave could be related to variations in some parameters of the ground and/or of the troposphere , which control the ground wave propagation mode. On the other hand, anomalies mainly appearing in the sky wave seem to be connected with disturbances in the ionosphere. In both the cases, such variations can be produced by the processes that take place during the preparatory phase of earthquakes
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
Variations in the relationship of seismic velocities before two earthquakes in Umbria (Italy)
No full textAppropriate 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
Studying the temporal variations of atmosphere physical properties at different spatial and temporal scales by VLF radio signals and space geodesy techniques
No full textAbstract
In this work we study the physical variations of atmosphere at different spatial and temporal scales. The temporal evolution of the amplitude of Very Low Frequency (VLF) radio signals is used as a means to characterize the seasonal variations of atmosphere. The microwave-based GNSS and Synthetic Aperture radar (SAR) interferometry techniques are used as a means to characterize anomalies in the physical properties of atmosphere due to solar X-ray flares
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