1,721,050 research outputs found
Slab damage and the pulsating retreat of the Ionian-Apennines subduction
No full textEpisodes of slow and fast plate subduction, slab rollback, and backarc opening are widely documented; e.g., in the central Mediterranean region. Pervasive damage by fluids is emerging as a possible weakening mechanism that could lead to slab segmentation and breakoff. We show that low-velocity anomalies within the Ionian slab present in along-dip seismic tomography profiles are traces of past damaging events generated by water penetration into the oceanic lithosphere when it was at the trench. We propose that the stepwise evolution of the central Mediterranean over the past 21 m.y. has been governed by strength changes of the Ionian slab induced by damage. More generally, we speculate that the cyclicity of such a process in space and time in the different circum-Mediterranean subduction events may have led to the present shape of the Mediterranean basin
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
Update of the Italian Seismic Catalog (2003-2007) Catalogo della Sismicità Italiana CSI v2.0
No full textEarthquake catalogues are the basic tools that furnish parametric data for seismic hazard evaluation, studies on evolution of seismic sequences and earthquake occurrence. The INGV seismic network
covers a large part of the italian region and it is complemented by several regional permanent network handled by other institutions. CSI results from the combination of INGV seismic bulletin with bulletins
produced by other institutions. To update CSI from previous release to version 2.0 we collected seismic bulletins sent to INGV from, at present, 12 institutions managing permanent seismic networks during
2003-2007. Procedures to convert different file formats to PHS format as input files of Hypoellipse program have been setup that also perform preliminary checks on possible errors.
To correctly merge different seismic bulletins it is mandatory to have a strict control on phase associations. To do this, additional procedures to identify earthquakes external to the interest area and wrong
associations of different earthquakes based on geographic control network associations and stations' residuals after event location have been produced.
About 35,000 eartquakes, a mean value of ~6600 earthquakes per year, with more than 600.000 P-phase arrivals and more then 250,000 S-phase arrivals have been collected and located with Hypoellipse.
To enhance final locations quality we applied a multiple location approach and then selected the best among several calculated hypocentres for each event. Location criteria are based on the use of two different
weighting schemes for stations' distance combined with several reference regional 1D velocity models.
Native Ml Magnitudes from 2003 to 2007 are retrieved and then associated to the corresponding event from INGV bulletin. When native Ml is not available, Ml based on regression law by Castello et al.
2007, is attributed.
The update of CSI catalog, also due to the strong improvement of the INGV seismic network between 2005 and present, offers a more complete image of the Italian seismicity and a new important reference
for further studies on the evolution of this region and earthquake occurrence.UnpublishedUniversità RomaTRE2T. Tettonica attivaope
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
Deep geometry of subduction below the Andean belt of Colombia as revealed by seismic tomography
No full textIn this study new tomographic models of Colombia were calculated. I used the seismicity recorded by
the Colombian seismic network during the period 2006-2009. In this time period, the improvement of
the seismic network yields more stable hypocentral results with respect to older data set and allows to
compute new 3D Vp and Vp/Vs models. The final dataset consists of 10813 P- and 8614 S-arrival
times associated to 1405 earthquakes. Tests with synthetic data and resolution analysis indicate that
velocity models are well constrained in central, western and southwestern Colombia to a depth of 160
km; the resolution is poor in the northern Colombia and close to Venezuela due to a lack of seismic
stations and seismicity.
The tomographic models and the relocated seismicity indicate the existence of E-SE subducting Nazca
lithosphere beneath central and southern Colombia. The North-South changes in Wadati-Benioff zone,
Vp & Vp/Vs pattern and volcanism, show that the downgoing plate is segmented by slab tears E-W
directed, suggesting the presence of three sectors. Earthquakes in the northernmost sector represent
most of the Colombian seimicity and concentrated on 100-170 km depth interval, beneath the Eastern
Cordillera. Here a massive dehydration is inferred, resulting from a delay in the eclogitization of a
thickened oceanic crust in a flat-subduction geometry. In this sector a cluster of intermediate-depth
seismicity (Bucaramanga Nest) is present beneath the elbow of the Eastern Cordillera, interpreted as
the result of massive and highly localized dehydration phenomenon caused by a hyper-hydrous oceanic
crust. The central and southern sectors, although different in Vp pattern show, conversely, a continuous,
steep and more homogeneous Wadati-Benioff zone with overlying volcanic areas. Here a "normalthickened"
oceanic crust is inferred, allowing for a gradual and continuous metamorphic reactions to
take place with depth, enabling the fluid migration towards the mantle wedge
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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