1,720,968 research outputs found
Feedback between fluid infiltration and rheology along a regional ductile-to-brittle shear zone: The East Tenda Shear Zone (Alpine Corsica)
No full textThe East Tenda Shear Zone (ETSZ) is themajor Alpine tectonic boundary marking the overthrusting
of the ocean-derived Schistes Lustrés nappe onto the Variscan crystalline basement of Corsica. New structural,
mineralogical, and geochemical investigations along a transect ranging from the Variscan basement to the
contact with the Schistes Lustrés are used to construct a rheological model for the ETSZ during its polyphase
deformation history. The progressive transformation of the isotropic granitoid protolith into gneisses, shear
zones, and, locally, phyllonites is described. The textural/mineralogical change suggests a concurrent increasing
metasomatism associated with structurally controlled fluid flow. The effect of such textural/mineralogical
evolution on the bulk rheology of the ETSZ is estimated. Rheological flow laws are obtained using an averaging
procedure based on the integration of single-phase rheological behavior. The flow laws are used to infer strain
rates and construct strength envelopes for each structural domain during progressive deformation, which
highlight the relative rheological differences of the main textural components of the ETSZ and the variations in
their brittle/ductile transition depths. Two competing processes are inferred. On the one hand, the combined
effects of the feldspar-to-mica reaction and the development of a strong planar fabric induce weakening and
strain localization along shear zones. On the other hand, fluid channeling along these shear zones enhances alkali
feldspar neoblastesis, inducing strain hardening. Among the possible consequences of such feedback processes
between strain localization andfluid-rock interaction are episodes of rheological transitions fromductile to brittle
behavior during the polyphase tectonic evolution of the ETSZ
LaP-Ramp geometry of fracturing in travertines: examples from the Acquasanta Terme deposits (Central Italy).
No full textTravertines are continental carbonatic rocks characterized by a poor layering with a strong internal lamination.
Travertines form by the interplay between chemical and microbial activity in a wide range of depositional environments
(from ponds to cascades) reflecting different hydrodynamics regimes. The resulting geometry show a typical
spatial anisotropy varying from decametric- to meter-scale. The internal lamination is provided by variations of the
depositional facies and it is mainly displayed by alternation of more porous and less porous horizons.
Despite the high primary porosity, these deposits present a low permeability, as attested by the presence of fossil
gas bubbles. It follows that pores interconnection (secondary permeability) is strongly influence both by primary
(depositional) and secondary (structural) factor.
The presence of internal lamination deeply influences the fracture trajectories characterized by a dual attitude with
parallel and cross-cutting segments.
Travertine deposits represent today a primary task in many, newly discovered, oil reservoirs in the Southern Atalantic.
The dimension of single fracture is under the resolution of seismic sections. Analogue field studies are thus
well required to properly model the secondary permeability features.
In this study we describe the patterns and the ways of fracturation in travertines. Fractures in Acquasanta-Terme
travertines are characterized by portions cutting through the lamination (ramp, R) and portion running parallel to
the internal lamination (lamination parallel, LaP). The combination of R and LaP results in a stairway geometry of
the fractures. A Montecarlo approach was successfully used to provide a suitable model of fractures development.
We found a relation between the average lamination dipping and the L/R ratio (computed dividing the cumulative
length of LaP over R segments) and a relation between the average lamination dip and the angle formed by the
intersection between R and LaP segments. These relations suggest that the lamination dipping of 25-30 represent
a critical angle reflecting the depositional rheology of the different depositional environments. The found
The found L-R fracture property assures a fracture connectivity within travertine deposit thus locally providing
effective permeability increase
LaP-Ramp geometry of fracturing in travertines: examples from the Acquasanta Terme deposits (Central Italy)
No full textTravertines are continental carbonatic rocks characterized by a poor layering with a strong internal lamination. Travertines form by the interplay between chemical and microbial activity in a wide range of depositional environments (from ponds to cascades) reflecting different hydrodynamics regimes. The resulting geometry show a typical spatial anisotropy varying from decametric- to meter-scale. The internal lamination is provided by variations of the depositional facies and it is mainly displayed by alternation of more porous and less porous horizons. Despite the high primary porosity, these deposits present a low permeability, as attested by the presence of fossil gas bubbles. It follows that pores interconnection (secondary permeability) is strongly influence both by primary (depositional) and secondary (structural) factor. The presence of internal lamination deeply influences the fracture trajectories characterized by a dual attitude with parallel and cross-cutting segments. Travertine deposits represent today a primary task in many, newly discovered, oil reservoirs in the Southern Atalantic. The dimension of single fracture is under the resolution of seismic sections. Analogue field studies are thus well required to properly model the secondary permeability features. In this study we describe the patterns and the ways of fracturation in travertines. Fractures in Acquasanta-Terme travertines are characterized by portions cutting through the lamination (ramp, R) and portion running parallel to the internal lamination (lamination parallel, LaP). The combination of R and LaP results in a stairway geometry of the fractures. A Montecarlo approach was successfully used to provide a suitable model of fractures development. We found a relation between the average lamination dipping and the L/R ratio (computed dividing the cumulative length of LaP over R segments) and a relation between the average lamination dip and the angle formed by the intersection between R and LaP segments. These relations suggest that the lamination dipping of 25-30 represent a critical angle reflecting the depositional rheology of the different depositional environments. The found The found L-R fracture property assures a fracture connectivity within travertine deposit thus locally providing effective permeability increase
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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