1,720,964 research outputs found
A preliminary report on the lacustrine succession of Sessano basin (Molise, southern Italy).
No full textThe lacustrine succession of the Sessano basin represents the filling of a N-S trending structural depression which is placed at the boundary between the Central and Southern Apennines thrust and fold belt. This belt was generated by a progressive north-eastward thrusting and stacking of passive margin sediments, essentially during the Cenozoic, and by the development of strike-slip tectonic regime during Late Pliocene and Early Pleistocene. A subsequent extensional tectonic phase, SW-NE trending, overprinted the compressional and transpressional structures. Detailed field surveys allowed us to establish that this extensional tectonic phase strongly controlled the geomorphologic evolution of the basin as well as the phases of lacustrine and fluvial sedimentation. In particular, structural analyses showed that the sedimentation was controlled by the activity of two sets of faults, N-S and NW-SE trending, which displaced and tilted the fluvio-lacustrine deposits towards ESE. To characterise the lacustrine succession, an 80 m deep core was drilled in the central part of the basin. The analysis of the core showed that the succession is made of lacustrine silts and clays, including various layers of black peat or fine sands. The latter become then dominant in the upper part of the core where a two metres thick bed of fluvial silicoclastic sands is present. Moreover, near the top of the sequence we can also observe whitish, 20-30 cm thick, volcano-clastic layers, some of which include pumices.The prevalence of coarser grained sediments in the upper part of the succession indicates the end of the lacustrine deposition and the establishment of a fluvial regime. In order to obtain further information on the paleoenvironmental evolution of the basin, 78 samples were taken along the core for pollen analysis. Preliminary results revealed the occurrence of at least two periods with contrasting climatic characters. In particular, in the basal part of the core pollen spectra show the dominance of herbaceous taxa, indicating typical glacial open environments. Towards the top this association is replaced by forest elements, both deciduous and altitudinal, which typically indicate an interglacial period. This glacial-interglacial cycle strongly resembles those already identified in other Middle Pleistocene paleolakes of southern Apennines. The floral composition suggests a late Middle Pleistocene age for the lacustrine cycle of the Sessano basin, according to our hypothesis that the basin took origin and was filled during Middle Pleistocene
An intergrated stratigraphical approach to the Middle Pleistocene succession of the Sessano basin (Molise, Italy)
No full textAn integrated stratigraphical approach was applied to the Sessano sedimentary succession (Molise),
investigated through an 80-m core and an 11-m trench section. The lithostratigraphical study allowed
reconstruction of the palaeoenvironmental conditions during the existence of a palaeo-marsh. Based on
tephrostratigraphical analysis, the significant volcanoclastic inputs recorded along the Sessano succession
were correlated to the explosive activity of the nearby Roccamonfina volcano and in particular to the
high-K series (HKS) period of activity, lasted from 546 to 364 ka. The 40Ar/39Ar age of 437.9 1.9 ka
obtained at the base of the trench section, which stratigraphically overlaps the core succession, confirms
the tephrostratigraphical model and indicates that the marsh dried up during the glacial phase of Marine
Isotope Stage (MIS) 12. On this basis, the glacial–interglacial cycle recognised in the core through pollen
analysis was ascribed to MIS 14 and 13, while the interglacial phase identified at the core base was
tentatively ascribed to MIS 15. The duration of the marshy phase was estimated between 130 and 150 ka.
The floral composition of the pollen spectra shows a more modern character with respect to coeval
pollen records from Campania, confirming that the heterochronous disappearance of the last subtropical
elements from Italy had a latitudinal character
The Abruzzi, Latium and Molise National Park (Central Italy): a proposal to exploit its geological heritage by a GIS supported geomorphologic mapping.
No full text
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
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
- …
