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191.
Vitis vinifera L. vineyards grown on carbonate soil (Hyblean Plateau, SE Sicily) have been characterized in terms of rare earth elements (REEs) distribution. Results highlighted that the absorption of REEs by plants depends on the composition of the underlying soil, which in this case derives from limestone parent rock, allowing us to recognize the area of origin. Indeed, even slight differences in REEs content in soils may affect the absorption pattern of each grapevine cultivar. Importantly, the various parts of the plants showed differences in REEs absorption; such REEs fractionation is particularly evident in the leaf and juice samples. In general, the uptake and concentrations of REEs in plant tissues may be related to many factors such as geographical, climatic and lithological features. This is also pointed out by the statistical investigation, which took into account either the grapevine variety or each part of the plant. By taking into consideration both the grape variety and the type of soil, the present “multi-elemental” approach aims to provide a useful geochemical tool for assessing the geographical origin of the production area of wine.  相似文献   
192.
The Calabria (Southern Italy) region is characterized by many geological hazards among which landslides, due to the geological, geomorphological, and climatic characteristics, constitute one of the major cause of significant and widespread damage. The present work aims to exploit a bivariate statistics-based approach for drafting a landslide susceptibility map in a specific scenario of the region (the Vitravo River catchment) to provide a useful and easy tool for future land planning. Landslides have been detected through air-photo interpretation and field surveys, by identifying both the landslide detachment zones (LDZ) and landslide bodies; a geospatial database of predisposing factors has been constructed using the ESRI ArcView 3.2 GIS. The landslide susceptibility has been assessed by computing the weighting values (Wi) for each class of the predisposing factors (lithology, proximity to fault and drainage line, land use, slope angle, aspect, plan curvature), thus evaluating the distribution of the landslide detachment zones within each class. The extracted predisposing factors maps have then been re-classified on the basis of the calculated weighting values (Wi) and by means of overlay processes. Finally, the landslide susceptibility map has been considered by five classes. It has been determined that a high percentage (61%) of the study area is characterized by a high to very high degree of susceptibility; clay and marly lithologies, and slope exceeding 20° in inclination would be much prone to landsliding. Furthermore, in order to ascertain the proposed landslide susceptibility estimate, a validation procedure has been carried out, by splitting the landslide detachment zones into two groups: a training and a validation set. By means of the training set, the susceptibility map has first been produced; then, it has been compared with the validation set. As a result, a great majority of LDZ-validation set (85%) would be located in highly and very highly susceptible areas. The predictive power of the model is considered reliable, since more than 50% of the LDZ fall into 20% of the most susceptible areas. The reliability of the susceptibility map is also suggested by computing the SCAI index, true positive and false positive rates; nevertheless, the most susceptible areas are overestimated. As a whole, the results indicate that landslide susceptibility assessment based on a bivariate statistics-based method in a GIS environment may be useful for land planning policy, especially when considering its cost/benefit ratio and the need of using an easy tool.  相似文献   
193.
We report results from the combined analysis of UV and radio observations of a CME-driven shock observed on 7 May 2004 above the southeast limb of the Sun at 1.86 R with the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SOHO). The coronal mass ejection (CME) was first detected in white-light by the SOHO’s Large Angle and Spectrometric Coronagraph (LASCO) C2 telescope and shock-associated type II metric emission was recorded simultaneously by ground-based radio spectrographs. The shock speed (∼ 690 km s−1), as deduced from the analysis of the type II emission drift in the radio spectra and the pre-shock local electron density estimated with the diagnostics provided by UVCS observations of the O vi λλ 1031.9, 1037.6 doublet line intensities, is just a factor ∼ 0.1 higher than the CME speed inferred by means of the white-light (and EUV) data in the middle corona. The local magnetosonic speed, computed from a standard magnetic field model, was estimated as high as ∼ 600 km s−1, implying that the CME speed was probably just sufficient to drive a weak fast-mode MHD shock ahead of the front. Simultaneously with the type II radio emission, significant changes in the O vi doublet line intensities and profiles were recorded in the UVCS spectra and found compatible with abrupt post-shock plasma acceleration and modest ion heating. This work provides further evidence for the CME-driven origin of the shocks observed in the middle corona.  相似文献   
194.
Gas samples from some fumaroles at ‘La Fossa' crater and Baia di Levante on Vulcano Island and from a diffuse soil gas emission were analysed during 1995–1996, along with water samples from thermal wells in the area of Vulcano Porto. During 1996, we observed a significant increase both in the gas/steam ratio and in the CO2 concentration, as well as strong variations in δ13CCO2, δDH2O and δ18OH2O of fumarolic gases. These variations are probably related to an increased inflow of deep fluids of magmatic origin. The temperatures of fumaroles did not show remarkable variations except for fumarole F11. In this case, temperature increased by about 80°C from February to August 1996. During the same period, remarkable variations in temperature, phreatic level and chemical and isotopic composition of water were also recorded in one of the geothermal wells in the Vulcano Porto area (Camping Sicilia; T60°C). The observed variations in this well are probably related to a pressure build-up, occurring at least in the surficial part of the system, because of increased gas flux and/or decreased permeability of the fumarolic degassing system. Chemical and isotopic composition of the water showed that during this evolutionary phase, the content of fumarolic condensate in this well was about 80 to 90%. Based on the observation of physical and chemical variables of the Camping Sicilia fluids, during this phase of activity, it is concluded that this area is affected by a phreatic eruption hazard if a volcanic episode with high energy discharge in a limited time span occurs. It follows that this well may be considered as a preferential point for volcanic activity monitoring, both in the case of normal routine surveillance and in the case of inaccessibility to the crater area.  相似文献   
195.
We investigate the elastic properties of the crust in the Gargano promontory, located in the northern part of the Apulia region (Southeastern Italy). Starting on April, 2013, a local-scale seismic network, composed of 12 short-period (1 Hz) seismic stations, was deployed on the Gargano promontory. Starting on October, 2013, the network was integrated with the recordings of nine seismic stations managed by the Italian Institute of Geophysics and Volcanology (INGV). The network recorded more than 1200 seismic events in about 15 months of data acquisition, with more than 700 small magnitude events localized in the Gargano promontory and surrounding areas. A Wadati-modified method allowed us to infer VP/VS = 1.73 for the area. A subset of about 400 events having a relatively smaller azimuthal gap (<200°) was selected to calibrate a 1D P-wave velocity model of the area, using the VELEST inversion code. The preferred model was obtained from the average of ten velocity models, each of them representing the inversion result from given initial velocity models, calibrated on previous geological and geophysical studies in the area. The results obtained under the assumption that VP could decrease with depth are unstable, with very different depths of the top of low-velocity layers. Therefore, the velocity model was obtained from the average of the results obtained under the assumption that VP cannot decrease with depth. A strong reduction of both RMS (about 58%) and errors on the location of the events was obtained with respect to the starting model. The final velocity model shows a strong velocity gradient in the upper 5 km of the crust and a small increase (from 6.7 to 7 km) at 30 km of depth. The epicenters of relocated events do not show clear correlations with the surface projection of known seismic faults. A cluster of the epicenters of the relocated events intersects almost perpendicularly the Candelaro fault trace at the surface.  相似文献   
196.
The work presented is aimed at the investigation of the influence of beam‐to‐column connections on the seismic response of MR‐Frames, with and without ‘set‐backs’, designed according to the Theory of Plastic Mechanism Control. The investigated connection typologies are four partial strength connections whose structural details have been designed to obtain the same flexural resistance. The first three joints are designed by means of hierarchy criteria based on the component approach and are characterized by different location of the weakest joint component, leading to different values of joint rotational stiffness and plastic rotation supply and affecting the shape of the hysteresis loops governing the dissipative capacity. The last typology is a beam‐to‐column connection equipped with friction pads devoted to the dissipation of the earthquake input energy, thus preventing the connection damage. An appropriate modelling is needed to accurately represent both strength and deformation characteristics, especially with reference to partial‐strength connections where the dissipation of the earthquake input energy occurs. To this aim, beam‐to‐column joints are modelled by means of rotational inelastic springs located at the ends of the beams whose moment‐rotation curve is characterized by a cyclic behaviour which accounts for stiffness and strength degradation and pinching phenomena. The parameters characterizing the cyclic hysteretic behaviour have been calibrated on the base of experimental results aiming to the best fitting. Successively, the prediction of the structural response of MR‐Frames, both regular frames and frames with set‐backs, equipped with such connections has been carried out by means of both push‐over and Incremental Dynamic Analyses. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
197.
Mollusc and annelid polychaete macrofaunal assemblages were studied in a sublittoral sandy bottom of 1.8 km2 extension, along the western Calabrian coast (low Tyrrhenian Sea). The strict coupling of the local sedimentary dynamics with the benthic assemblages was investigated on a small spatial scale (patchiness), at the mesoscale depth-related gradients and at the level of functional/trophic habits. Non-metrical correlations (ρ), index of dispersion (Di) and dispersion weighted abundances, averaged per depth level highlighted the response of some characteristic species to the patchiness of sediments as well as to the predominant environmental gradients. Species habits and trophic guilds, that were assessed in terms of biomass (wet weight) and secondary “pseudo-production” (abundance × biomass), clarified the differential functional response of the assemblages at different depth levels. Polychaetes reached 84.86% abundance and showed a highly clumped distribution of sessile species (Ditrupa arietina, Aponuphis brementi, Chone acustica, Spiophanes kroyeri); to a lower extent the motile species (Hyalinoecia tubicola, Marphisa bellii, Phylo foetida) were present. Molluscs reached 15.14% abundance and only some bivalve taxa showed significant aggregated distributions (Corbula gibba, Tellina donacina, Tellina distorta), whereas gastropod species were more evenly distributed. Total biomasses were almost equal between the two taxonomic groups (46.41 g WW on average). Biotic–environmental rank matching highlighted depth, very fine sands (60–200 μm), sorting grade, skewness index and pH as being the most influential factors in the distributions of some species, followed secondarily by coarse silts (40–60 μm) and coarser sands (200–2000 μm). Within the local context of water/sediment oligotrophy, the adaptive strategies of macrofauna to a highly seasonal supply of autochthonous phytoplanktonic seston associated with imported macro debris and terrigenous components were emphasized. Evidence of such a differential nutrient supply was the clear functional differentiation of the shallower levels from the deeper ones, and the presence of an intermediate zone which was selectively dominated, in terms of abundance and biomass, by microphagous filter/suspension feeders. Moreover, the shortage of burrowing deposit feeders as well as the prevalence of motile macrophagous omnivores beyond 20 m depth may be considered as ecologically correlated aspects.  相似文献   
198.
Geoarchaeological investigations in an area surrounding the confluence of the upper Colorado and Concho Rivers, Edwards Plateau of West Texas, have produced a detailed landscape evolution model which provides a framework for discussion of the influences of geomorphic processes on the development, preservation, and visibility of the archaeological record. Field mapping within the study area has differentiated six allostrati-graphic units of fluvial origin in both valleys, as well as extensive eolian sand sheets along the Colorado River. Early to middle Pleistocene terrace remnants cap many upland areas, whereas two distinct late Pleistocene terrace surfaces are widespread within the study area at somewhat lower elevations. Fluvial activity during the time period of human occupation is represented by an extensive Holocene terrace and underlying valley fill, which is up to 11 m in thickness. Valley fill sediments can be subdivided into allostratigraphic units of early to middle Holocene (ca. 10,000–5000 yr B.P.) and late Holocene age (ca. 4600–1000 yr B.P.), which are separated by a buried soil profile. The modern incised channels and very narrow floodplains represent the last millennium. Eolian sand sheets of early to middle Holocene age overlie limestone- and shale-dominated uplands, Pleistocene terraces, and in some cases the Holocene valley fill along the Colorado River. Pleistocene terraces have been stable features in the landscape and available for settlement through the time period of human occupation. Archaeological materials of all ages occur at the surface, and the record preserved in individual sites range from that associated with discrete periods of activity to longer-term palimpsests that represent repeated use over millennia. Sites within early to middle Holocene and late Holocene fills represent short-term utilization of constructional floodplains during the Paleoindian through early Archaic and middle to late Archaic time periods respectively. By contrast, those that occur along the buried soil profile developed in the early to middle Holocene fill record middle to late Archaic cultural activity on stable terrace surfaces, and represent relatively discrete periods of activity to longer-term palimpsests that represent repeated use over the 3000–4000 years of subaerial exposure. Late Prehistoric sites occur as palimpsests on soils developed in late Holocene alluvium or stratified within modern floodplain facies. Paleoindian through Late Prehistoric sites occur stratified within eolian sand sheets or along the unconformity with subjacent fluvial deposits. The landscape evolution model from the upper Colorado and Concho Rivers is similar to that developed for other major valley axes of the Edwards Plateau. This model may be regionally applicable, and can be used to interpret the geomorphic setting and natural formation processes for already known sites, as well as provide an organizational framework for systematic surface and subsurface survey for new archaeological records. 0 1992 John Wiley & Sons, Inc.  相似文献   
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