Trace elements in farmed and wild gilthead seabream, Sparus aurata     

Vincenzo Minganti  Giuliana Drava  Rodolfo De Pellegrini  Camilla Siccardi 《Marine pollution bulletin》2010,60(11):2022-2025

In the present study, we sought to determine the concentration of several trace elements (total and organic mercury, selenium, cadmium, lead, arsenic, copper, chromium, iron, manganese, molybdenum, vanadium and zinc) in muscle tissue of gilthead seabream (Sparus aurata), an edible finfish species that is widely cultured in the Mediterranean area. The phenomenon of bioaccumulation and bioamplification (especially of mercury) was investigated by comparing farmed fish with wild specimens of the same species. Farmed specimens showed mercury and arsenic concentrations significantly lower than wild specimens, and no relationship was found between mercury concentration and body size. The lower level of methylmercury in farmed fish has important implications for consumer health.  相似文献   

Water‐bottom multiple attenuation by Kirchhoff extrapolation     

Emmanuel Spadavecchia  Vincenzo Lipari  Nicola Bienati  Giuseppe Drufuca 《Geophysical Prospecting》2013,61(4):725-734

Despite being less general than 3D surface‐related multiple elimination (3D‐SRME), multiple prediction based on wavefield extrapolation can still be of interest, because it is less CPU and I/O demanding than 3D‐SRME and moreover it does not require any prior data regularization. Here we propose a fast implementation of water‐bottom multiple prediction that uses the Kirchhoff formulation of wavefield extrapolation. With wavefield extrapolation multiple prediction is usually obtained through the cascade of two extrapolation steps. Actually by applying the Fermat’s principle (i.e., minimum reflection traveltime) we show that the cascade of two operators can be replaced by a single approximated extrapolation step. The approximation holds as long as the water bottom is not too complex. Indeed the proposed approach has proved to work well on synthetic and field data when the water bottom is such that wavefront triplications are negligible, as happens in many practical situations.  相似文献   

Author's Reply     

Vincenzo Silvestri 《Ground water》2013,51(2):169-169

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A neuro fuzzy approach to recognize rock magnetic and lithological patterns in a stratigraphic well from the Llanos Foreland Basin (Colombia)     

Victoria Camacho  Diego López-Rodríguez  Vincenzo Costanzo-Álvarez  Milagrosa Aldana  Nuri Hurtado  Germán Bayona 《Studia Geophysica et Geodaetica》2013,57(4):669-691

The Neuro Fuzzy System (NFS) is a hybrid algorithm that combines fuzzy logic with neural networks. Since it can be used as a pattern recognition technique, we explore its potential to characterize the major lithological units encompassed by the first 512 m of the Colombian stratigraphic well Saltarin 1A (Guayabo and León Formations). Thus, we employ the NFS to infer the magnetic remanence S-ratio using bulk magnetic susceptibility (κ), κ-normalized saturation isothermal magnetization (SIRM κ) and/or volume of shale (V_sh) obtained from a gamma-ray log. The best results in terms of their corresponding Root Mean-Square Error (RMSE) values, throughout most of the upper Guayabo Formation, where magnetite seems to be an important magnetic phase, are attained with logκ and SIRM κ as input variables. Beyond 350 m downcore, the quality of the inference decreases over the León Formation, characterized by a significant presence of pyrrhotite. However, the extra input variable V_sh adjusts the inferred S-ratio to their experimental counterparts throughout this formation suggesting that the early diagenesis process that led to the formation of dispersed clay in these samples was also responsible for the formation of pyrrhotite. Hence the inclusion of manifold input data increases the ability of the net to predict S-ratio in complex geological settings with a sequence of changing lithologies, varying amounts and types of magnetic minerals, and different distributions of mineral grain sizes. In case these variables do not properly infer the actual S-ratio data, the extent of the different lithostratigraphic units would be still identifiable in some cases by the uneven quality of the correlation observed between inferred and experimental values.  相似文献   

Numerical relationships between magnetic parameters measured in Quaternary sediments and global paleoclimatic proxies     

Alfredo Peralta  Vincenzo Costanzo-Alvarez  Eduardo Carrillo  Leonardo Evert Durán  Milagrosa Aldana  Daniel Rey 《Studia Geophysica et Geodaetica》2013,57(4):647-668

The complexity of most geological and geophysical problems prompts sometimes the use of non linear mathematical methods to handle them. An adaptive neuro fuzzy inference system (ANFIS) that combines fuzzy logic with neural networks, is applied here to study a paleoclimate section from the Quaternary sedimentary fill of the Lake Mucubají (western Venezuela). The purpose of this work is to find a set of numerical relationships that could predict the possible connections between oxygen isotope (δ¹⁸O) values from two different locations in the northern hemisphere (Ammersee in southern Germany and an ice core from the Greenland Ice Core Project — GRIP) and rock-magnetic parameters measured in Mucubají samples (i.e. mass-specific magnetic susceptibility — χ, magnetic remanence S-ratio, mass-specific saturation isothermal remanent magnetization — SIRM and anhysteretic remanent magnetization — ARM). The best inferences in terms of coefficient of determionation R² and the Root Mean-Square Error (RMSE) are obtained using those magnetic data as input that include information about magnetite grain size distributions, e.g., SIRM and ARM in FIS structures [1χ, 4ARM] and [4ARM, 1SIRM]. A comparison between Ammersee and GRIP actual data, as well as their corresponding inferences for the FIS structure [4ARM, 1SIRM], reveals a reasonable good inference of global trends for both records, overlooking the regional and/or local paleoclimate forcings that might have affected Ammersee. A better correlation between global isotope paleoclimate records and magnetic proxies, is perhaps prevented by the role played by local and regional paleoclimate and tectonism in Mucubají. We also argue that the ratio of ARM over SIRM appears to be related in a complex way to the onset and to the end of the Younger Dryas. Our novel approach to the assessment of a specific paleoclimate case study shows the potential of the ANFIS technique in solving problems where traditional univariate and multivariate linear regression methods could prove inadequate.  相似文献   

Assessment of <Emphasis Type="Italic">pre-crisis</Emphasis> and <Emphasis Type="Italic">syn-crisis</Emphasis> seismic hazard at Campi Flegrei and Mt. Vesuvius volcanoes,Campania, southern Italy     

Vincenzo Convertito  Aldo Zollo 《Bulletin of Volcanology》2011,73(6):767-783

In this study, we address the issue of short-term to medium-term probabilistic seismic hazard analysis for two volcanic areas, Campi Flegrei caldera and Mt. Vesuvius in the Campania region of southern Italy. Two different phases of the volcanic activity are considered. The first, which we term the pre-crisis phase, concerns the present quiescent state of the volcanoes that is characterized by low-to-moderate seismicity. The second phase, syn-crisis, concerns the unrest phase that can potentially lead to eruption. For the Campi Flegrei case study, we analyzed the pattern of seismicity during the 1982–1984 ground uplift episode (bradyseism). For Mt. Vesuvius, two different time-evolutionary models for seismicity were adopted, corresponding to different ways in which the volcano might erupt. We performed a site-specific analysis, linked with the hazard map, to investigate the effects of input parameters, in terms of source geometry, mean activity rate, periods of data collection, and return periods, for the syn-crisis phase. The analysis in the present study of the pre-crisis phase allowed a comparison of the results of probabilistic seismic hazard analysis for the two study areas with those provided in the Italian national hazard map. For the Mt. Vesuvius area in particular, the results show that the hazard can be greater than that reported in the national hazard map when information at a local scale is used. For the syn-crisis phase, the main result is that the data recorded during the early months of the unrest phase are substantially representative of the seismic hazard during the whole duration of the crisis.  相似文献   

The Pozzo del Sale Groundwaters (Irpinia, Southern Apennines, Italy): Origin and Mechanisms of Salinization     

Tiziano Boschetti  Vincenzo De Felice  Fulvio Celico 《Aquatic Geochemistry》2013,19(4):303-322

Chemical and water isotope ratios data for groundwaters from the Pozzo del Sale area in the Irpinia sector of the Southern Apennines are presented. The water chemistry of the aquifer system may initially be regarded as the result of easy and common, low temperature interaction between meteoric water and Late Messinian evaporites, which produce Ca-bicarbonate and Na-chloride passing through Ca-sulfate waters. However, a closer inspection reveals a more complicated geochemical setting consisting of: (1) two further Na-sulfate and Ca(Mg)-sulfate waters; (2) the existence of different meteoric recharge areas; (3) the mixing between the different groundwaters and allochthonous fluids from terrestrial mud volcanoes. The salinization mechanism and the local mineralogy were inferred by classical and novel ternary and binary diagrams. The presence of MgSO₄- and Na₂SO₄-bearing minerals of non-marine or mixed origin other than gypsum and halite within the local evaporites suggests a mineralogical heterogeneity within the local Messinian evaporites. The paleoenvironment of this sector of the Gessoso–Solfifera Formation might have been composed of relatively small playa-lakes fed by seawater but also large amounts of continental waters of meteoric origin.  相似文献   

Re-assessment of foundation settlements for the Burj Khalifa, Dubai     

Gianpiero Russo  Vincenzo Abagnara  Harry G. Poulos  John C. Small 《Acta Geotechnica》2013,8(1):3-15

This paper deals with the re-assessment of foundation settlements for the Burj Khalifa Tower in Dubai. The foundation system for the tower is a piled raft, founded on deep deposits of calcareous rocks. Two computer programs, Geotechnical Analysis of Raft with Piles (GARP) and Non-linear Analysis of Piled Rafts (NAPRA) have been used for the settlement analyses, and the paper outlines the procedure adopted to re-assess the foundation settlements based on a careful interpretation of load tests on trial piles in which the interaction effects of the pile test set-up are allowed for. The paper then examines the influence of a series of factors on the computed settlements. In order to obtain reasonable estimates of differential settlements within the system, it is found desirable to incorporate the effects of the superstructure stiffness which act to increase the stiffness of the overall foundation system. Values of average and differential settlements for the piled raft calculated with GARP and NAPRA were found to be in reasonable agreement with measured data on settlements taken near the end of construction of the tower.  相似文献   

Cave clastic sediments as a tool for refining the study of human occupation of prehistoric sites: insights from the cave site of La Cala (Cilento,southern Italy)          下载免费PDF全文

Ivan Martini  Annamaria Ronchitelli  Simona Arrighi  Giulia Capecchi  Stefano Ricci  Sem Scaramucci  Vincenzo Spagnolo  Paolo Gambassini  Adriana Moroni 《第四纪科学杂志》2018,33(5):586-596

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Hercynian subduction-related processes within the metamorphic continental crust in Calabria (southern Italy)     

Fabrizio Tursi  Richard Spiess  Vincenzo Festa  Rosa Anna Fregola 《Journal of Metamorphic Geology》2020,38(7):771-793

Linking the deformation history of mylonitized continental rocks to the progress of devolatilization reactions that trigger reaction softening is critical for the understanding of crustal scale processes. We have analysed the field geometries and microstructures of deformed rocks within the southern Hercynian belt in Calabria, as well as modelled the pressure–temperature–deformation (P–T–d) trajectory of a main ductile shear zone that tectonically coupled the deeper crustal Mammola Paragneiss Unit with the upper crustal Stilo–Pazzano Phyllite Unit. P–T modelling of the mylonitic Mammola Paragneiss Unit was performed through calculation of phase equilibrium diagrams with the software thermocalc in the MnNCKFMASHTO model system. The prograde P–T–d trajectory is based on the zoning profiles of garnet porphyroblasts and their mineral inclusions, primarily barroisite and epidote. P–T modelling shows that peak metamorphic conditions of ~0.9 GPa and 585°C were reached during a D_n-1 under-thrusting event. The following exhumation during the D_n mylonitic event, and contact metamorphism during D_n+1 and D_n+2 folding events, have also been modelled because they are essential to restore the previous tectono-metamorphic history. The exhumation trajectory was modelled down to 0.3 GPa with temperatures of 440–460°C, under fluid-deficient conditions, as well as the final late Carboniferous contact metamorphism up to T_max of 680–720°C. The prograde path shows clear evidence for thermal buffering during garnet growth at the expense of chlorite, with a heating-dominated stage after chlorite breakdown. Subsequently, a rheological change associated with epidote breakdown (i.e. reaction softening) occurred, highlighted by a net steepening of the P/T trajectory towards the pressure peak. On the basis of the barroisite inclusions within garnet porphyroblasts as well as the ‘hairpin’ shape of the reconstructed P–T–d path (before contact metamorphism), we infer that the unusual low T/P gradient for the Hercynian crust exposed in the Mammola Paragneiss Unit records its involvement in the Palaeotethys–Gondwana subduction beneath Laurussia during D_n-1 under-thrusting. We present a new palaeotectonic interpretation along the southern Hercynian belt in Calabria during the Upper Mississippian–Lower Pennsylvanian, that is consistent with previous geochronology studies.  相似文献