1,721,005 research outputs found
Il record paleobiologico dei livelli anossici pleistocenici della sezione Samoggia (Appennino settentrionale)
No full text[The palaeobiological record of Pleistocene anoxic levels in the Samoggia section (northern Apennines)]. The integrated study of planktic and benthic assemblages of foraminifera from the Samoggia River section (northern Apennines, Italy), allows reconstruction of paleoenvironmental scenarios during the early Pleistocene. Up to 24 sapropels have been recognized in the section. The faunal succession suggests a basin with low salinity in the upper part of the water column and low oxygen content at the sea-bottom. High-resolution micropaleontological investigations allow identification of two intervals characterized by different paleoclimatic and paleoenvironmental conditions: the lower one starting from the Plio-Pleistocene boundary to 1.5 Ma, and the upper one from 1.5 Ma to 1.31 Ma
Miocene seep-carbonates as indicators of fluid migration in northern Apennines (Italy).
No full text--
Late Miocene seep-carbonates and fluid migration on top of the Montepetra intrabasinal high (Northern Apennines, Italy): Relations with synsedimentary folding
No full textDuring the Miocene, hydrocarbon seep-carbonates located atop intrabasinal highs and associated with sediment instability, formed commonly at the deformation front of the Northern Apennine collisional orogen. The parallelism between the structural trend and the distribution of seep-carbonates suggests a close relationship between tectonics and gas/fluid emission.
The “Montepetra intrabasinal high” was formed during the closure stage of the foredeep, being related to the synsedimentary growth of an anticline. Field geometry suggests that detachment folding was the leading
mechanism of anticline growth and synsedimentary instability along the anticline flanks. Ten different bodies of seep-carbonates occur in the Tortonian–early Messinian sediments: nine in the hinge zone and one
in the southern backlimb of the anticline.
Foraminiferal study, geochemistry, facies investigation and the three-dimensional geometry of carbonate bodies with respect to the encasing terrigenous sediments indicate a protracted (late Tortonian–early
Messinian) activity of fluid migration with re-mobilization and ascent of sediments from the core of the anticline, stabilization of chemosynthesis-related communities, and in-situ brecciation.
Seepage atop the intrabasinal high was fed by different circuits: one related to the compaction-dewatering of shallow (Tortonian–early Messinian) sediments, and a deeper one related to the deformation of the anticline core and to the activity of detachment surfaces and of faults propagating through the sedimentary cover
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
Methane seepages recorded in benthic foraminifera from Miocene seep carbonates, Northern Apennines (Italy)
No full textBenthic foraminifera from seep carbonates and from enclosing non-seep marls present within Miocene formations in the Northern Apennines (Italy) were investigated as proxies of methane seepage in the marine environment Negative delta(13)C values of benthic foraminifera from these seeps indicate unambiguously the local influence of CO(2) produced by microbial anaerobic methane oxidation on the benthic ecosystem. Calcareous species living within methane seeps display delta(13)C values ranging from -9.04 to -25.74 parts per thousand PDB, whereas in the coeval surrounding marls the same species display delta(13)C values from -1.54 to 0.62 parts per thousand PDB. Different species (Cibicidoides kullenbergi C. pachyderma, Siphonina rethiculata, Planulina wuellestorfi, Bolivina miocenica, Brizalina dilatata, Vulvulina pennatula, and Cibicides praecinctus) in different seep carbonates indicate that benthic foraminifera, independently of the taxa and of microhabitat preferences, have more negative delta(13)C values than those found in the enclosing marls. Therefore each species represents a potential proxy for past seafloor methane emissions. In addition to the calcareous species, the agglutinated species Vulvulina pennatula displays -27.5 parts per thousand PDB in seep carbonates against -2.69 parts per thousand PDB in the enclosing marls. This suggests that the species utilized strongly (13)C depleted carbonate particles from authigenic carbonate precipitation during the mineralization of their tests
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
Fossil microbial communities in the evaporite deposits of the Vena del Gesso (northern Apennines, Italy).
No full textSeep-carbonates at the top of a growing anticline: the "Montepetra structural high" of Northern Apennines (Italy).
No full text- …
