1,720,979 research outputs found
Spatial association of mud volcano and sandstone intrusions, Boyadag anticline, western Turkmenistan
Full text linkAcknowledgements The Authors are indebted with Dr. Barbara Cerasetti, scientific coordinator of the Italian Archaeological Program in Turkmenistan (Dipartimento di Storia, Culture, Civiltà – Università di Bologna – Ministero per gli Affari Esteri – MAE), for the logistical help before and during the field activities in Turkmenistan. Our thanks to the administration of the National Institute of Deserts, Flora and Fauna, to the Turkmenistan Government and to Dr Aman Nigarov for the fruitful assistance in the field. We thank Prof. Marco Antonellini for the discussions on sandstone intrusions. The authors are indebted to the reviewers J. Peakall, P. Imbert, A. Hurst and an anonymous reviewer for the very helpful comments to the manuscript. Funding was provided by Prof. G. Gabbianelli for the field survey and by PRIN 2009 grants to Prof. Rossella Capozzi.Peer reviewe
A genetic model of hydrocarbon-derived carbonate chimneys in shelfal fine-grained sediments: The Enza River field, Northern Apennines (Italy)
Full text linkMethane Derived Authigenic Carbonate (MDAC) concretions have been recently exposed in the Pleistocene Argille Azzurre Fm. outcropping along the Enza riverbanks, Northern Apennines foothills, Italy.
The relations between the sediment deposition, the coeval tectonic deformation and the MDAC concretions have been investigated to unravel the mechanism of methane migration through the sediments and the processes leading to MDAC occurrence. The biogenic methane responsible for the formation of MDAC chimneys and slabs has been generated in the organic-rich Pliocene sediments located in the Po Plain subsurface. The gas migrated up-dip towards the Northern Apennines foothills. The MDAC cements are mainly composed of dolomite, whose precipitation requires thousand years and the absence of SO4 in the pore fluids. According with the sedimentation rates of the MDAC-hosting Pleistocene succession, the Sulphate Methane Transition Zone migrated upwards faster than time required for dolomite precipitation.
Therefore, the connate water migrating together with the methane could have acted as second DIC source, allowing the MDAC formation also in the methane-rich zone
Fluid sources and stable isotope signatures in authigenic carbonates from the Northern Apennines, Italy
Full text linkFunding was provided by the Italian PRIN 2009 Project (MIUR research grant to R. Capozzi) and by the Royal Society of Edinburgh (grant to D. Oppo). The authors wish to thank Joachim Reitner (Department of Geobiology, Centre for Geosciences, Georg-August-University of Göttingen, Germany), Stefano Bernasconi (Department of Earth Sciences, Geologisches Institut, ETH Zurich, CH) and Mario Mussi (CNR-Institute for Geosciences and Georesources, CNR-IGG, Pisa) for contributing in the stable isotopes analyses on carbonate samples; and to two anonymous reviewers.Peer reviewe
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
Active faulting controls bedform development on a deep-water fan
Full text linkTectonically controlled topography influences deep-water sedimentary systems. Using 3-D seismic reflection data from the Levant Basin, eastern Mediterranean Sea, we investigate the spatial and temporal evolution of bedforms on a deep-water fan cut by an active normal fault. In the footwall, the fan comprises cyclic steps and antidunes along its axial and external portions, respectively, which we interpret to result from the spatial variation in flow velocity due to the loss of confinement at the canyon mouth. Conversely, in the hanging wall, the seafloor is nearly featureless at seismic scale. Numerical modeling of turbidity currents shows that the fault triggers a hydraulic jump that suppresses the flow velocity downstream, which thus explains the lack of visible bedforms basinward. This study shows that the topography generated by active normal faulting controls the downslope evolution of turbidity currents and the associated bedforms and that seafloor geomorphology can be used to evince syn-tectonic deposition
Mass wasting records the first stages of the Messinian Salinity Crisis in the eastern Mediterranean
No full textDispelling 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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