1,720,972 research outputs found
Continental subduction and exhumation: an example from the Ulten Unit, Tonale nappe, Eastern Austroalpine.
No full textSome exhumed complexes in collisional belts consist of continental basement containing slivers of mafic and ultramafic material showing evidence of UHP metamorphism (P c. 3 GPa). Their PTt history can be interpreted in terms of subduction of continental material to depths ≥ 100 km and subsequent exhumation. This type of tectonic history is illu strated by the Late Palaeozoic evolution of the Ulten Unit, Tonale Nappe, Eastern Austroalpine. The upper crustal felsic component (c. 80% by volume) incorporated mafic material at the trench, and peridotitic material at deeper levels in the subduction zone. The peridotites show evidence of a P-increasing, T-decreasing path before incorporation in the felsic material, compatible with flow in the mantle wedge above the subducting slab. After emplacement of the peridotites, which occurred at or near peak metamorphic conditions (P ≥ 2.7 GPa, T ≥ 850 °C), the complex underwent a two-stage pre-Alpine exhumation path: a first, fast stage (c. 0.1-1 cm a-1), lasting c. 30 Ma and bringing rocks from depths ≥ 100 km to approximately 25 km; and a second, slow stage (c. 0.01-0.1 cm a-1), lasting c. 100 Ma and bringing rocks to depths 200 km if attached to a mature oceanic slab that does not break-off during the early stages of continental subduction. The first exhumation stage can be accounted for by buoyancy-driven tectonic extrusion of continental slices along the subduction channel during continuing subduction. A force balance analysis shows that such a mechanism is compatible with the rheology of felsic and intermediate rocks at high temperature. The second exhumation stage is compatible with isostatic rebound and tectonic denudation following slab break-off. The conclusion that fast exhumation occurs during continuing subduction and before slab break-off is in accordance with the observed rates, which show fast movement of the rising slices with respect to the surrounding material. Slab break-off, on the other hand, generates a long-wavelength gentle upwarping of the overlying region, which is more compatible with later and slower exhumation rates. © The Geological Society of London 2005
Active deformation and crustal rheology in the central-eastern Alps (N Italy) from accurate earthquake relocations
No full textA revised seismic catalogue (1994–2007) for the central–eastern Alps (N Italy) is presented. 396 earthquake
relocations, for local magnitudes in the 1.2–5.3 range, are performed using a 3D crustal velocity structure and
probabilistic locations. The location procedure is validated by computing a set of 41 quarry shot solutions and
all the results, both about shots and seismic events, are comparedwith those obtained using the routine location
procedure. Results are shown for five contiguous seismotectonic domains, as supported by geological and geophysical
evidence (e.g., fault systems, crustal tomography, focal mechanisms types). Earthquake hypocentres
are mostly located in the upper crust (0–15 km of depth), in good agreement with thermo-rheological models
about the brittle–ductile transitions (8–9 km of depth) and total crustal strengths (1.0–2.0 TN m−1). Epicentres
are clustered and/or aligned along present-day active geological structures. The proposed seismotectonicmodel
shows dominant compression along the Giudicarie and Belluno–Bassano–Montello thrusts, with strain
partitioning along the dominant right-lateral strike-slip faults of the Schio–Vicenza domain. The present-day deformation
of the Southern Alps and the internal Alpine chain is compatiblewith Adria indentation and the related
crustal stress distribution
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
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