1,721,022 research outputs found
Rapid differentiation in a sill-like magma reservoir: a case study from the campi flegrei caldera
No full textIn recent decades, geophysical investigations have detected wide magma reservoirs beneath quiescent
calderas. However, the discovery of partially melted horizons inside the crust is not sufficient to put
constraints on capability of reservoirs to supply cataclysmic eruptions, which strictly depends on the
chemical-physical properties of magmas (composition, viscosity, gas content etc.), and thus on their
differentiation histories. In this study, by using geochemical, isotopic and textural records of rocks erupted
from the high-risk Campi Flegrei caldera, we show that the alkaline magmas have evolved toward a critical
state of explosive behaviour over a time span shorter than the repose time of most volcanic systems and that
these magmas have risen rapidly toward the surface. Moreover, similar results on the depth and timescale of
magma storage were previously obtained for the neighbouring Somma-Vesuvius volcano. This consistency
suggests that there might be a unique long-lived magma pool beneath the whole Neapolitan area.Publishedarticle 7122.3. TTC - Laboratori di chimica e fisica delle rocce3.5. Geologia e storia dei vulcani ed evoluzione dei magmi3.6. Fisica del vulcanismo4.3. TTC - Scenari di pericolosità vulcanicaN/A or not JCRope
Correlazione tra sismicità ed elementi strutturali nell'Isola d'Ischia.
No full textAn integrated study on historical seismicity and tectonic structures has made it possible to recognize the relationships between macroseismic data and strain field in the northern part of the island of ischia (Gulf of Naples, Southern Italy). Macroseismic maps based on new data and information from the literature suggest that the epicentral area was probably located in a restricted area that coincides with the northern border of Mt. Epomeo "horsf; this is the most conspicuous morphostructural feature of the island and is thought to control both seismic and tectonic activity in the island. Isoseismal lines have a clear E-W trend; the maximum gradient is oriented N-S and coincides with the least damaged areas. Kinematic analyses of the faults in the volcanic deposits of Casamicciola (a village on the north of Mt. Epomeo), indicate a principal extension along the N to NNE direction in the oldest (> 35 ka) tuffs; a secondary extension and transtension occur along a NNW direction and seem to affect also younger (10*2 ka) pumiceous formations. Both extensional episodes are localized on E-W to WNW-ESE trending structures. Major dip-slip displacements present along the Mt. Epomeo border faults are markedly attenuated to the east, where younger volcanic edifices (< 10 ka) seem to seal most of the deformation structures. This situation conforms to the geometry of isoseismal lines and suggests a possible geneticai Sink between macroseismic and local strain fields, in turn controlled by the regional strain field of Southern Italy
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
Magma degassing and crystallization processes during eruptions of high-risk Neapolitan-volcanoes: Evidence of common equilibrium rising processes in alkaline magmas
No full textCompositional, textural and experimental data on products from explosive and effusive eruptions of Neapolitan volcanoes (Campi
Flegrei and Somma-Vesuvio) allow us to constrain degassing and fragmentation conditions during eruptions of alkaline magmas.
Significant differences in compositional and textural features have been recognized between lavas, scoria and pumice resulting
respectively from effusive, moderately and extremely explosive eruptions. Pumice samples have highly-vesicular glassy matrix, low
microlite number density and moderate to high water content. Crystal Size Distributions (CSD) are steep with high intercept values; the
narrow microlite size range indicates single nucleation event. Scoria products are characterized by moderate vesicularity and water
content. They have high number density of microlites which are bimodal in size. CSD show distinct inflections that are explained as two
crystal populations growing in distinct time. Lava samples generally have low vesicularities, moderate to high microcrystalline
groundmass and low glass water content. The comparison between textural and compositional features of natural rocks with samples
obtained by decompression experiments allows us to conclude that degassing processes during magma ascent occurs in near-equilibrium
conditions even at high decompression rate. Moderate to long magma rise times, calculated in the order of a few days, produce opendegassing
responsible formoderately explosive to effusive activity. Shortmagma rise times, calculated in the order of a fewhours, result in
closed-system degassing that allow explosive fragmentation when the volume of growing bubble reaches a fixed threshold. Vesicularity
and water content measured on matrix glass of pumice indicate that this process occurs at pressure of 10–30 MPa. In these conditions,
degassing, fragmentation and in turn the eruptive style is strongly influenced by initial conditions in themagma chamber (volatile content,
temperature, pressure) instead of decompression rate, in contrast with that observed for rhyolitic melts. These differences have important
consequences in terms of volcanic hazards and risk. The low-viscosity alkaline magma is able tomaintain efficient degassing even during
the final stage of magma ascent, favoring, in the case of closed-system, fragmentation and explosive activity.Published164-181reserve
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