130,405 research outputs found
The occurrence of the genus Tanousia Servain (Hydrobiidae) in the Middle Pleistocene Piànico-Sèllere Basin (Bergamo, N Italy): palaeoclimatical and chronostratigraphical meaning.
No full textThe occurrence of the freshwater genus Tanousia Servain 1881 (Hydrobiidae) in the Middle Pleistocene lacustrine succession of the
Pia` nico-Se` llere Basin (Bergamo, Northern Italy) represents a significant biostratigraphical discovery. The Tanousia were recovered from
the basal part of the carbonate varved bed (BVC), in siltysandy slump sediments, and from the lower and middle parts of the La
Palazzina Member (MLP) of the Pia` nico formation. The BVC unit, in which a dated tephra layer occurs, accumulated during an
interglacial phase, as shown by pollen analyses. The MLP Tanousia-bearing layers have been laid down during cool–temperate climate
oscillation. The Pia` nico population of Tanousia displays great morphological variability but is similar to T. runtoniana (Sandberger,
1880), T. stenostoma (Nordmann, 1901) and T. cf. T. stenostoma (Nordmann, 1901), from the Bavelian and Cromerian interglacial
deposits of late Early and early Middle Pleistocene age in Northern Europe. As for these species, the Tanousia population from Pia` nico
appears to indicate fluvial conditions under a fully temperate climate
The malacological record from the Piànico-Sèllere basin (Northern Italy).
No full textNon-marine molluscs, Palaeoecology, Piànico-Sèllere Basin, Northern Italy
A new finding of the genus Tanousia Servain (Hydrobiidae) from the Piànico-Sèllere basin (Bergamo, N Italy): palaeoclimatic and chronostratigraphic meaning.
No full textProve malacologiche dell’evoluzione regressiva nel margine settentrionale lombardo del bacino padano durante il Pleistocene inferiore e medio, rilevate nel sondaggio “Trezzo RL5” (Trezzo sull’Adda, MI).
No full textA revision of the Triassic sequence stratigraphic framework of the Dolomites (Italy). The impact of climate, volcanics, tectonic and changes in the carbonate factories.
No full textSeismic-scale outcrops, the high-resolution bio-chrono-stratigraphic framework and the scarce alpine deformation render the Dolomites (Southern Alps, north-eastern Italy) an ideal reference for the Triassic global sequence stratigraphic charts (Haq et al., 1987; Gianolla & Jacquin, 1998; Hardenbol et al., 1998). However, the Triassic of the Dolomites is the result of a complex set of forcings, which determined a large variability of the carbonate sedimentary successions that includes ramps, carbonate banks, high-relief isolated or attached carbonate platforms, with different carbonate factories. The possibility to read the coeval response of carbonate and siliciclastic depositional systems to such different sedimentary forcings as sea level oscillations, climate change and volcanic activity make this region a playground to test the limits and the potentials of the sequence stratigraphic methodology.
Recently, the sequence stratigraphic framework of the Dolomites was carried out according to the approaches summarized in Catuneanu et al. (2011). The revision of the depositional sequences (DSa) allowed to better define: a) the surfaces that delimit the different system tracts; b) the influence of tectonics in the timing of the DSs stacking patterns; c) the role of changing carbonate factories in the architecture of carbonate depositional systems; d) the impact of climate and/or environmental changes in the demise of carbonate systems and supply of siliciclastic sediments; e) the impact of local volcanic activity on sediment supply and carbonate production shut-off, ; and lastly g) the hierarchy of the identified depositional sequences. This led to a revised sequence stratigraphic framework (Fig. 1), characterized with respect to the original schemes (e.g., Gianolla et al., 1998) by a lower number of DSs, by the identification of FSSTs in many DSs, and by a better age control for sequence stratigraphic surfaces.
One example is the impact, in the Dolomites, of the "Carnian Pluvial Event", a global episode of climate change documented worldwide at low latitudes, that involved increased rainfall and possibly global warming. This climatic event predates a drop of sea-level and caused the demise of microbial dominated high-relief carbonate platforms that dominated the region. It was followed by the coexistence of small microbial carbonate mounds and loose arenaceous carbonates. A subsequent sea level fall brought to the definitive disappearance of microbialites and shallow water carbonates switched to ramps dominated by loose carbonate sediment. The climate-induced crisis of Early Carnian shallow water carbonate systems of the Dolomites generated a geological surface similar to a drowning unconformity, although no transgression occurred. The sudden infilling of basins at the end of the Early Carnian was the result of the climatic-induced switch from high-relief carbonate systems characterized by steep slopes to a gently inclined ramp, rather than by the continuous progradation of a high- relief microbial platform.
Results show that the evolution of carbonate systems of the Dolomites at the end of the Early Carnian cannot be interpreted in the light of sea level changes only, pointing out that ecological changes can induce significant modifications in depositional geometries
Variation in shell morphology in the fossil freshwater gastropod Tanousia subovata (SETTEPASSI 1965) from the Mercure Basin (Middle Pleistocene, southern Italy): Distinct taxa or ecophenotypic variation? (Gastropoda Prosobranchia: Hydrobiidae)
No full textThe study of the shell plasticity of the extinct Hydrobiidae Tanousia subovata (SETTEPASSI 1965) resulted in a better understanding of the relationships between the shape of the organisms and the environment that influenced their life. Three populations, from distinct sections of the lacustrine Middle Pleistocene Mercure Basin (Basilicata-Calabria, southern Italy), have been investigated, using a landmark-based geometric morphometric analysis to quantify the morphological variability. Morphometric data and data coming from independent proxies (such as lithology and other fossils), already published on the studied basin, have been taken into account. Results have been interpreted to discriminate between internal and external factors influencing the shape of the shell. The geometric morphometric method proved useful to reveal some morphological variations between the three populations, which, following the comparisons with palaeoenvironmental data and with the literature appear to result from ecological or maybe chronological factors rather than indicating distinct species
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
Triassic Sequence Stratigraphy of Western European Basins. An introduction.
No full textThe Triassic western European succession comprises at least four transgressive-regressive second order facies cycles which can be followed from the Boreal siliciclastic to the Tethyan carbonate settings. The exact timing of the peak transgression and maximum regression of these cycles vary slightly from basin to basin according to local physiographic conditions, tectonic behaviour and sediment supply. Up to twenty-four third order depositional sequences are the building blocks of the second order facies cycles. They form a good framework for correlation across basins and across facies belts. A major first order transgressive-regressive facies cycle also formed during Triassic time. Its lowermost and uppermost boundaries do not necessarily match with the Triassic system boundaries but, depending to the authors, with the P/T boundary or the Hardegsen unconformity (Late Scythian) for the lowermost one and with the Early Cimmerian unconformity (Late Norian) for the uppermost one
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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