1,720,958 research outputs found
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
Morphostructural Study of the Chambon Lake Basin (Eastern Slope of the Monts Dore Massif, Massif Central, France)
No full textThe Chambon Lake area, located between the Col de la Croix-Morand and Murol (Massif Central, France), consists of a Hercynian basement partially covered by Cenozoic formations. The topography, sedimentation, and drainage network are strongly controlled by a complex fault system. A detailed morphostructural analysis identified over 500 lineaments from a high-resolution DEM, digitized and analyzed in a GIS environment using QGIS. A directional classification, combining expert-based interpretation with a semi-supervised machine learning approach (k-means algorithm), revealed seven major fault families grouped into clusters consistent with a regional dextral shear regime.An interpretive model is proposed, consistent with the current stress field (σ 1 between N160°E and N180°E). The F1 faults are interpreted as dextral shear zones within the South Armorican Shear Zone -Cholet-Poitiers Fault -Southern Margin Fault of the Limagne system, accompanied by secondary Riedel-type structures. The influence of the Sillon Houiller, a sinistral shear zone, is also recognized in fault groups F6 ′′ and F2 ′ .The proposed neotectonic framework allows for the interpretation of several geomorphological features: the Chambon Lake basin may correspond to a transtensional pull-apart structure, and the slow landslide at Chambon-sur-Lac could be controlled by the extensional faults F4 and F6 ′′ .Finally, the study suggests that deep hydrothermal activity at Chambon-sur-Lac may be linked to regional seismicity associated with the F1 fault system.</div
Multi-step vesicle and shear-parting evolution as a record of syn-and post-emplacement deformation and cooling dynamics of 'a'a and pahoehoe lavas
No full textWhile bubbles play an intimate role in determining lava flow dynamics, the resultant vesicle shapes and distributions provide insights into the temporal and spatial evolution of lava flow emplacement. We here examine the size and shape of voids (due to vesiculation and shearing), and relate circularity to degree of deformation, for a well-exposed lava flow at Lemptégy volcano (Chaîne des Puys, France). Using high-spatial resolution imaging and textural analysis, we establish a quantitative framework to distinguish between undeformed and deformed vesicles, and fractured vesicles and their development into shear partings. Rheological modeling, using a model that evolves as the lava cools, plus calculated strain rates and shear stresses, reveal how void space deformation evolves under changing flow regimes. Our model traces a progression from initial bubble deformation under flow-induced stress, to the formation of fractures within brittle layers as cooling advances. Highly deformed bubbles occur in still fluid lava at strain rates of >7 s -1 and viscosities of 10 4 -10 7 Pa s. However, as the lava solidifies, down-slope creep takes over with well-formed shear partings developing at high mechanical stresses. In our case, this transition began after a few hours, with flow lateral creep resulting from surface up-lift due to the emplacement of a cryptodome. This study provides a method of automatically classifying void space types that make up total rock porosity and uses the time-dependent evolution of void space types to recreate and quantify syn-and post-emplacement dynamics.</div
Multi-step vesicle and shear-parting evolution as a record of syn-and post-emplacement deformation and cooling dynamics of 'a'a and pahoehoe lavas
No full textWhile bubbles play an intimate role in determining lava flow dynamics, the resultant vesicle shapes and distributions provide insights into the temporal and spatial evolution of lava flow emplacement. We here examine the size and shape of voids (due to vesiculation and shearing), and relate circularity to degree of deformation, for a well-exposed lava flow at Lemptégy volcano (Chaîne des Puys, France). Using high-spatial resolution imaging and textural analysis, we establish a quantitative framework to distinguish between undeformed and deformed vesicles, and fractured vesicles and their development into shear partings. Rheological modeling, using a model that evolves as the lava cools, plus calculated strain rates and shear stresses, reveal how void space deformation evolves under changing flow regimes. Our model traces a progression from initial bubble deformation under flow-induced stress, to the formation of fractures within brittle layers as cooling advances. Highly deformed bubbles occur in still fluid lava at strain rates of >7 s -1 and viscosities of 10 4 -10 7 Pa s. However, as the lava solidifies, down-slope creep takes over with well-formed shear partings developing at high mechanical stresses. In our case, this transition began after a few hours, with flow lateral creep resulting from surface up-lift due to the emplacement of a cryptodome. This study provides a method of automatically classifying void space types that make up total rock porosity and uses the time-dependent evolution of void space types to recreate and quantify syn-and post-emplacement dynamics.</div
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
Morphostructural Study of the Chambon Lake Basin (Eastern Slope of the Monts Dore Massif, Massif Central, France)
No full textThe Chambon Lake area, located between the Col de la Croix-Morand and Murol (Massif Central, France), consists of a Hercynian basement partially covered by Cenozoic formations. The topography, sedimentation, and drainage network are strongly controlled by a complex fault system. A detailed morphostructural analysis identified over 500 lineaments from a high-resolution DEM, digitized and analyzed in a GIS environment using QGIS. A directional classification, combining expert-based interpretation with a semi-supervised machine learning approach (k-means algorithm), revealed seven major fault families grouped into clusters consistent with a regional dextral shear regime.An interpretive model is proposed, consistent with the current stress field (σ 1 between N160°E and N180°E). The F1 faults are interpreted as dextral shear zones within the South Armorican Shear Zone -Cholet-Poitiers Fault -Southern Margin Fault of the Limagne system, accompanied by secondary Riedel-type structures. The influence of the Sillon Houiller, a sinistral shear zone, is also recognized in fault groups F6 ′′ and F2 ′ .The proposed neotectonic framework allows for the interpretation of several geomorphological features: the Chambon Lake basin may correspond to a transtensional pull-apart structure, and the slow landslide at Chambon-sur-Lac could be controlled by the extensional faults F4 and F6 ′′ .Finally, the study suggests that deep hydrothermal activity at Chambon-sur-Lac may be linked to regional seismicity associated with the F1 fault system.</div
Multi-step vesicle and shear-parting evolution as a record of syn-and post-emplacement deformation and cooling dynamics of 'a'a and pahoehoe lavas
No full textWhile bubbles play an intimate role in determining lava flow dynamics, the resultant vesicle shapes and distributions provide insights into the temporal and spatial evolution of lava flow emplacement. We here examine the size and shape of voids (due to vesiculation and shearing), and relate circularity to degree of deformation, for a well-exposed lava flow at Lemptégy volcano (Chaîne des Puys, France). Using high-spatial resolution imaging and textural analysis, we establish a quantitative framework to distinguish between undeformed and deformed vesicles, and fractured vesicles and their development into shear partings. Rheological modeling, using a model that evolves as the lava cools, plus calculated strain rates and shear stresses, reveal how void space deformation evolves under changing flow regimes. Our model traces a progression from initial bubble deformation under flow-induced stress, to the formation of fractures within brittle layers as cooling advances. Highly deformed bubbles occur in still fluid lava at strain rates of >7 s -1 and viscosities of 10 4 -10 7 Pa s. However, as the lava solidifies, down-slope creep takes over with well-formed shear partings developing at high mechanical stresses. In our case, this transition began after a few hours, with flow lateral creep resulting from surface up-lift due to the emplacement of a cryptodome. This study provides a method of automatically classifying void space types that make up total rock porosity and uses the time-dependent evolution of void space types to recreate and quantify syn-and post-emplacement dynamics.</div
Morphostructural Study of the Chambon Lake Basin (Eastern Slope of the Monts Dore Massif, Massif Central, France)
No full textThe Chambon Lake area, located between the Col de la Croix-Morand and Murol (Massif Central, France), consists of a Hercynian basement partially covered by Cenozoic formations. The topography, sedimentation, and drainage network are strongly controlled by a complex fault system. A detailed morphostructural analysis identified over 500 lineaments from a high-resolution DEM, digitized and analyzed in a GIS environment using QGIS. A directional classification, combining expert-based interpretation with a semi-supervised machine learning approach (k-means algorithm), revealed seven major fault families grouped into clusters consistent with a regional dextral shear regime.An interpretive model is proposed, consistent with the current stress field (σ 1 between N160°E and N180°E). The F1 faults are interpreted as dextral shear zones within the South Armorican Shear Zone -Cholet-Poitiers Fault -Southern Margin Fault of the Limagne system, accompanied by secondary Riedel-type structures. The influence of the Sillon Houiller, a sinistral shear zone, is also recognized in fault groups F6 ′′ and F2 ′ .The proposed neotectonic framework allows for the interpretation of several geomorphological features: the Chambon Lake basin may correspond to a transtensional pull-apart structure, and the slow landslide at Chambon-sur-Lac could be controlled by the extensional faults F4 and F6 ′′ .Finally, the study suggests that deep hydrothermal activity at Chambon-sur-Lac may be linked to regional seismicity associated with the F1 fault system.</div
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