1,721,212 research outputs found
On the use of unconformities in volcanic stratigraphy and mapping: Insights from the Aeolian Islands (southern Italy)
No full textThe approach to volcanic stratigraphy and mapping in the Aeolian Islands has found the concept of Unconformity-Bounded Units (UBUs) extremely useful for purposes of stratigraphic classification and correlation. Volcanic unconformities (erosive and collapse unconformities) relative to processes of internal modification of a volcano are classified separately from sea level-driven unconformities. The erosive unconformities formed during periods of volcanic quiescence are generally characterized by angular relationships and lithological change between the products below and above an unconformity, and may be associated with paleosols or epiclastic horizons. The collapse unconformities related to calderas and lateral collapses represent surfaces of structural truncation along the collapse borders, passing outside of the collapse to erosive unconformities developed during the corresponding repose periods. Instead, the sea level-driven unconformities are marine and subaerial erosive surfaces bounding in pairs the depositional cycles relative to sea level highstands, which are recorded in raised marine terraces. Most unconformities can be correlated on a variable scale from local (volcanic island) to regional (inter-island) by means of careful stratigraphic analysis targeted to identify the corresponding stratigraphic hiatus in the volcanic successions in different points of observation. This helps to solve the problems arising from the difficult recognition of the unconformities in the field moving away from the type locality due to their variable features. A practical nomenclature scheme for a hierarchy of UBUs to be applied in volcanic areas can be established on the basis of the areal magnitude of the bounding unconformities and their importance in the volcano history, passing through a slight modification of the International Stratigraphic Guide's rules. Combined with lithostratigraphic units (mapped rock bodies) and lithosomes (eruptive centres), the UBUs provide a useful stratigraphic synthesis of a volcanic area by means of a framework of time-stratigraphic unconformable surfaces. Moreover, UBUs can be directly interpreted in terms of volcanic activity units with a time-stratigraphic significance, thus providing the key elements for the eruptive history of a volcano and the definition of its event stratigraphy
Revisiting turbidites of the Marnoso-arenacea Formation and their basin-margin equivalents: problems with classic models
No full textPreliminary design of a long range windowless aircraft concept
Full text linkThe objective of this paper is to describe the preliminary design of a windowless configuration of a long-range aircraft and to analytically assess the achieved weight reduction. As a matter of fact, the reduction of weight is directly linked with reduction of fuel consumption; consequently there are advantages in terms of aircraft operative costs and emissions of carbon dioxide. A feasibility study will bring to the assessment of weight and cost reduction in consideration to the introduction of innovative screens, to give passengers the possibility to see through the fuselage itself. The proposed methodology consists in the preliminary design of a long-range aircraft, considering some defined design parameters and constraints. The activity will finally lead to weight reduction evaluation, in case the same aircraft will be designed windowless. In the end the methodology is applied to two existing aircrafts to estimate potential benefits of the windowless configuration if compared to the traditional one: the Airbus 340-500 and the Being 777-300
Guide book for the Excursion in the Northern Apennines.International School of Earth and planetary Sciences.
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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
Reply to the discussion by Ganapathy Shanmugam on "Turbidities and turbidity currents from Alpine flysch to the exploration of continental margins’" by Mutti et al. (2009)
No full textVariations 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
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