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291.
Rosalda Punturo Carmelisa D’Antone Salvatore Pepi Carmela Vaccaro 《Environmental Earth Sciences》2018,77(24):801
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
292.
Application and validation of bivariate GIS-based landslide susceptibility assessment for the Vitravo river catchment (Calabria,south Italy) 总被引:3,自引:1,他引:2
Massimo Conforti Gaetano Robustelli Francesco Muto Salvatore Critelli 《Natural Hazards》2012,61(1):127-141
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
293.
We present a review of elemental abundances in the Milky Way stellar disk, bulge, and halo with a focus on data derived from high-resolution stellar spectra. These data are fundamental in disentangling the formation history and subsequent evolution of the Milky Way. Information from such data is still limited and confined to narrowly defined stellar samples. The astrometric Gaia satellite will soon be launched by the European Space Agency. Its final data set will revolutionize information on the motions of a billion stars in the Milky Way. This will be complemented by several ground-based observational campaigns, in particular spectroscopic follow-up to study elemental abundances in the stars in detail. Our review shows the very rich and intriguing picture built from rather small and local samples. The Gaia data deserve to be complemented by data of the same high quality that have been collected for the solar neighborhood. 相似文献
294.
Salvatore Mancuso 《Solar physics》2011,273(2):511-523
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
295.
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