1,721,000 research outputs found
An overview of the 20-year collaboration between NATO and earth scientists to assess geohazards in the caucasus and other critical regions
No full textWe hereby provide an overview of four multi-year projects on geohazard assessment and mitigation, carried out under the umbrella of the North Atlantic Treaty Organization (NATO), with the involvement of more than 80 scientists coming from several countries, among which the US, Georgia, Italy, Russia, Azerbaijan. The projects have been aimed at enhancing the security of people and the safety of vital infrastructures as well as facilitating cooperation between scientists from NATO and non-NATO countries. The study areas are located in the Caucasus (Georgia), in Central Asia (Kyrgyzstan) and Northeast Asia (Kamchatka). Our work clearly demonstrates how Earth Science can contribute to improving scientific collaboration among countries that are politically in tension; moreover, geoscience can play a key role in preventing situations that may escalate into conflicts. This paper showcases the main results of the NATO-funded projects, both in terms of their scientific relevance and their geopolitical importance
Inversion kinematics at deep-seated gravity slope deformations revealed by trenching techniques
Full text linkWe compare data from three deep-seated gravitational slope deformations (DSGSDs) where palaeoseismological techniques were applied in artificial trenches. At all trenches, located in metamorphic rocks of the Italian Alps, there is evidence of extensional deformation given by normal movements along slip planes dipping downhill or uphill, and/or fissures, as expected in gravitational failure. However, we document and illustrate - with the aid of trenching - evidence of reverse movements. The reverse slips occurred mostly along the same planes along which normal slip occurred, and they produced drag folds in unconsolidated Holocene sediments as well as the superimposition of substrate rocks on Holocene sediments. The studied trenches indicate that reverse slip might occur not only at the toe portions of DSGSDs but also in their central-upper portions. When the age relationships between the two deformation kinematics can be determined, they clearly indicate that reverse slips postdate normal ones. Our data suggest that, during the development of long-lived DSGSDs, inversion kinematics may occur in different sectors of the unstable rock mass. The inversion is interpreted as due either to locking of the frontal blocks of a DSGSD or to the relative decrease in the rate of downward movement in the frontal blocks with respect to the rear blocks
Strike-slip fault tectonics and the emplacement of sheet-laccolith systems: the Thverfell case study (SW Iceland)
No full textFault geometry and kinematics indicate that two different tectonic regimes affected the late Pliocene volcanic succession around the Thverfell magmatic complex (Esja peninsula, SW Iceland): The older phase is characterized by sets of left-lateral strike-slip, E-W- to ESE-striking faults and right-lateral strike-slip, N-S- to NE-striking faults; the younger phase produced normal dip-slip, NNE-striking faults. Stress tensor calculation for the older regime provides a horizontal, NE- to E-W-trending greatest principal stress (Ï1) and a horizontal NW- to N-S-trending least principal stress (Ï3), followed by a stress regime change with a vertical Ï1 and a WNW-trending Ï3. Structural-stratigraphic analyses of the eroded Thverfell magmatic complex indicate three main systems, namely (i) a centrally-dipping sheet swarm, E-W-elongated in plan view, (ii) a sill-composed laccolith, fed by E-W-striking dikes, and (iii) NNE- to NE-striking dikes offsetting the previous intrusions. These data allow unravelling of a multiphase history of magma-tectonics interaction. First, an excess magma pressure from an underlying magma chamber induced the emplacement of the centrally-dipping sheets; this was accompanied by magma upwelling along dikes that bent to propagate as sills under the influence of stress and rheological barriers induced by the lava overburden. Finally, regional dikes linked to the WNW-trending rift extension were emplaced. © 2007 Elsevier Ltd. All rights reserved
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
Interaction between transform faults and rift systems: a combined field and experimental approach
No full textWe present a detailed field structural survey of the area of interaction between the active NW-striking transform Husavik-Flatey Fault (HFF) and the N-S Theystareykir Fissure Swarm (TFS), in North Iceland, integrated by analogue scaled models. Field data contribute to a better understanding of how transform faults work, at a much higher detail than classical marine geophysical studies. Analogue experiments are conducted to analyse the fracture patterns resulting from different possible cases where transform faulting accompanies or postpones the rift motions; different tectonic block configurations are also considered. West of the intersection between the transform fault (HFF) and the rift zone (TFS), the former splays with a gradual bending giving rise to a leading extensional imbricate fan. The westernmost structure of the rift, the N-S Gudfinnugja Fault (GF), is divided into two segments: the southern segment makes a junction with the HFF and is part of the imbricate fan; north of the junction instead, the northern GF appears right-laterally offset by about 20 m. Southeast of the junction, along the possible prolongation of the HFF across the TFS, the strike of the rift faults rotates in an anticlockwise direction, attaining a NNW-SSE orientation. Moreover, the TFS faults north of the HFF prolongation are fewer and have smaller offsets than those located to the south. Through the comparison between the structural data collected in the field at the HFF-TFS connection zone and a set of scaled experiments, we confirm a prolongation of the HFF through the rift, although here the transform fault has a much lower slip-rate than west of the junction. Our data suggest that transform fault terminations may be more complex than previously known, and propagate across a rift through a modification of the rift pattern
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
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