1,721,102 research outputs found
Cold seepages: An economic toolfor hydrocarbon appraisal
No full text"Spontaneous cold fluid seepages are a renowned phenomenon occurring in a wide range of geologic and geodynamic settings, including deep sea fans, rapidly subsiding basins, and compressive tectonic settings (e.g., Dimitrov, 2002; Morley et al., 2011; Oppo et al., 2013, 2014). Cold seepages are marked by various struc- tures, both on land and offshore, such as mud volcanoes (MVs), methane-derived authigenic carbonates (MDACs), and chemo- symbiotic communities. Their formation mechanism requires the increase of pore-fluid pressure above the lithostatic gradient with the subsequent upward fluid migration through hydro- fracturing or along carrier beds and tectonic discontinuities."
"Cold seepages have long been investigated, especially for the information that they may provide for the exploration of hydrocarbons present in different types of reservoirs associ- ated with this phenomenon (e.g., Link, 1952; Heggland, 1998; Abrams, 2005). Although the relation between cold seepages and hydrocarbon reservoirs has not been completely enlightened in numerous settings, as in fold and thrust belts, it is established that the occurrence of gas, frequently associated with oil, is a common characteristic that most of the seepage areas show. In particular, the spontaneous leakage of oil and gas represents a prime indication of hydrocarbons occurrence in the subsurface and valuable source of information on the petroleum system. The associated fluids also provide evidence of the geochemistry of deep-seated hydrocarbons. A useful example of this association is represented by the oil and gas field exploited near MVs along the coast and offshore in the Caspian Sea (e.g., Planke et al.,"
"2003; Davies and Stewart, 2005; Oppo et al., 2014; Oppo and"
"Capozzi, 2016).
Messinian Lago-Mare mollusc fauna from the Gorgona Island slope, Tyrrhenian Sea
No full textLate Miocene Lago-Mare macrofossiliferous sediments were recovered in the northeastern Tyrrhenian Sea by dredging the continental slope off Gorgona Island, Tuscan Archipelago, at 300–470 m depth. The fossil assemblage consists of a rich lymnocardiid bivalve fauna dominated by Pontalmyra ex gr. P. incerta (Deshayes), associated with Dreissena ex gr. D. rostriformis (Deshayes), Pontalmyra cf. partschi (Mayer), ‘‘Limnocardium’’ sp., the gastropods Melanopsis narzolina (D’Archiac), Melanopsis sp. and cf. Saccoia sp. All bivalve taxa recognized at species level are of Paratethyan (Pontian) affinity and widespread in the Late Miocene of the Mediterranean Basin while M. narzolina has so far only recorded from the Mediterranean Basin. This finding represents the most diverse Lago-Mare macrofauna reported thus far from any submerged location in the Mediterranean Basin and documents that the post-evaporitic Cusercoli Formation contributes to the syn-rift neoautochthonous units of this sector of the Northern Tyrrhenian Sea
From lake to sea: The malacological signature of the inundation.
No full textThe history of the postglacial marine flooding of the Black Sea from the Mediterranean Sea is well documented by drastic faunal turnovers, although still highly controversial in details regarding tempo and mode (Ryan et al. 2003; Yanko-Hombach et al. 2007; Giosan et al. 2009 and many others). The paleobiological legacy found in the Black Sea sedimentary record admirably documents that this basin was a lacustrine environment of substantial size (the Late Neoeuxinian Lake: Yanko-Hombach et al. 2007) that somehow abruptly turned into marine conditions as Mediterranean sealevel reached up enough to breach through the Dardanelles and Bosphorus straits.
Sedimentary cores collected in the northweswestern Black Sea in the frame of the BLASON project contain an excellent malacological documentation of pre-flood lacustrine and syn- and post-flood marine environments
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
Testing the applicability of DNA barcoding for Mediterranean species of top-shells (Gastropoda, Trochidae, Gibbula s.l.)
No full textWe employed the COI sequences from specimens of top-shells to: (a) test the applicability of COI as a barcode marker for the trochid genus Gibbula s.l.; (b) provide a first taxonomically reliable data set of COI sequences useful for future studies; and (c) detect evidence of suspect intraspecific variability over a large geographical scale. We analysed a data set of 150 sequences from specimens morphologically ascribed to 17 putative species of Gibbula from the Mediterranean Sea and northeastern Atlantic, including the type species of 9 taxa traditionally considered as subgenera of Gibbula and representing over 50% of the roughly two dozen Mediterranean species, and also provided the DNA barcode for the endangered Maltese top-shell Gibbula nivosa. The analysis of the data set revealed that the COI is an effective barcode for the identification of the northeastern Atlantic top-shells, and also provides a tool to detect cryptic diversity
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
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