Heavy metals in sediments from different environments of a northern Adriatic Sea area,Italy     

S. Guerzoni  M. Frignani  P. Giordani  F. Frascari 《Environmental Geology》1984,6(2):111-119

Sediments from different environments of an area directly affected by the discharge of the Po River and 13 other minor rivers have been studied. Three main sources of metals and several distribution mechanisms can be identified. Concentration profiles of metals in a core allow one to establish background levels of finegrained sediments for Cd, Hg, Pb, and Zn Seabed sediments do not appear to be very polluted, mainly because of desorption and dilution processes  相似文献   

Polymorphism in sapphirine     

Stefano Merlino 《Contributions to Mineralogy and Petrology》1973,41(1):23-29

Sapphirine-1Tc, a polymorph of sapphirine, was found in granulites near Wilson Lake, Labrador. It is triclinic with unit cell data: a=10.04, b=10.38, c=8.65 Å, =107°33, =95°07, =123°55. The X-ray diffraction patterns of several crystals of sapphirine from Wilson Lake were investigated and evidence was found of solid state reactions that lead from the ordered polymorph-1Tc to a disordered arrangement of domains with the structure of sapphirine-2M, that is normal sapphirine.  相似文献   

Mutual Interference of Two Debris Flow Deposits Delivered in a Downstream River Reach   总被引：1，自引：0，他引：1  

STANCANELLI Laura Maria  LANZONI Stefano  FOTI Enrico 《山地科学学报》2014,(6):1385-1395

We investigate experimentally the depositions of two contiguous debris flows flowing into a main river reach.The aim of the present experimental research is to analyze the geometry and the mutual interactions of debris flow deposits conveyed by these tributaries in the main channel.A set of 19 experiments has been conducted considering three values of the confluence angle,two slopes of the tributary,and three different triggering conditions（debris flows occurring simultaneously in the tributaries,or occurring first either in the upstream or in the downstream tributary）.The flow rate along the main channel was always kept constant.During each experiment the two tributaries had the same slope and confluence angle.The analysis of the data collected during the experimental tests indicates that the volume of the debris fan is mainly controlled by the slope angle,as expected,while the shape of the debris deposit is strongly influenced by the confluence angle.Moreover,in the case of multiple debris flows,the deposit shape is sensitive to the triggering conditions.Critical index for damming formation available in literature has been considered and applied to the present case,and,on the basis of the collected data,considerations about possible extension of such indexes to the case of multiple confluences are finally proposed.  相似文献   

Improving Bayesian analysis for LISA Pathfinder using an efficient Markov Chain Monte Carlo method     

Luigi Ferraioli  Edward K. Porter  Michele Armano  Heather Audley  Giuseppe Congedo  Ingo Diepholz  Ferran Gibert  Martin Hewitson  Mauro Hueller  Nikolaos Karnesis  Natalia Korsakova  Miquel Nofrarias  Eric Plagnol  Stefano Vitale 《Experimental Astronomy》2014,37(1):109-125

We present a parameter estimation procedure based on a Bayesian framework by applying a Markov Chain Monte Carlo algorithm to the calibration of the dynamical parameters of the LISA Pathfinder satellite. The method is based on the Metropolis-Hastings algorithm and a two-stage annealing treatment in order to ensure an effective exploration of the parameter space at the beginning of the chain. We compare two versions of the algorithm with an application to a LISA Pathfinder data analysis problem. The two algorithms share the same heating strategy but with one moving in coordinate directions using proposals from a multivariate Gaussian distribution, while the other uses the natural logarithm of some parameters and proposes jumps in the eigen-space of the Fisher Information matrix. The algorithm proposing jumps in the eigen-space of the Fisher Information matrix demonstrates a higher acceptance rate and a slightly better convergence towards the equilibrium parameter distributions in the application to LISA Pathfinder data. For this experiment, we return parameter values that are all within ～1σ of the injected values. When we analyse the accuracy of our parameter estimation in terms of the effect they have on the force-per-unit of mass noise, we find that the induced errors are three orders of magnitude less than the expected experimental uncertainty in the power spectral density.  相似文献   

Synthetic observations using POLARIS: an application to simulations of massive prestellar cores     

Zamponi  Joaquin  Giannetti  Andrea  Bovino  Stefano  Sabatini  Giovanni  Schleicher  Dominik R. G.  K&#;rtgen  Bastian  Reissl  Stefan  Wolf  Sebastian 《Astrophysics and Space Science》2022,367(6):1-9

Astrophysics and Space Science - Dynamical evolution of galaxies is a complex process, especially the centers. Gravitationally coupled gas and stellar discs have been observed to coexist in the...  相似文献   

Shallow-landslide susceptibility in the Costa Viola mountain ridge (southern Calabria,Italy) with considerations on the role of causal factors   总被引：2，自引：1，他引：1  

Giulio G. R. Iovine  Roberto Greco  Stefano L. Gariano  Annamaria D. Pellegrino  Oreste G. Terranova 《Natural Hazards》2014,73(1):111-136

The “Costa Viola” mountain ridge (southern Calabria), in the sector between Bagnara Calabra and Scilla, is particularly exposed to geo-hydrological risk conditions. The study area has repeatedly been affected by slope instability events in the last decades, mainly related to debris slides, rock falls and debris flows. These types of slope movements are among the most destructive and dangerous for people and infrastructures, and are characterized by abrupt onset and extremely rapid movements. Susceptibility evaluations to shallow landslides have been performed by only focusing on source activation. A logistic regression approach has been applied to estimating the presence/absence of sources in terms of probability, on the basis of linear statistical relationships with a set of territorial variables. An inventory map of 181 sources, obtained from interpretation of air photographs taken in 1954–1955, has been used as training set, and another map of 81 sources, extracted from 1990 to 1991 photographs, has been adopted for validation purposes. An initial set of 12 territorial variables (i.e. lithology, land use, soil sand percentage, elevation, slope angle, aspect, across-slope and down-slope curvatures, topographic wetness index, distance to road, distance to fault and index of daily rainfall) has been considered. The adopted regression procedure consists of the following steps: (1) parameterization of the independent variables, (2) sampling, (3) calibration, (4) application and (5) evaluation of the forecasting capability. The “best set” of variables could be identified by iteratively excluding one variable at a time, and comparing the ROC results. Through a sensitivity analysis, the role of the considered factors in predisposing shallow slope failures in the study area has been evaluated. The results obtained for the Costa Viola mountain ridge can be considered acceptable, as 98.1 % of the cells are correctly classified. According to the susceptibility map, the village of Scilla and its surroundings fall in the highest susceptibility class.  相似文献   

Relationships between seep-carbonates,mud volcanism and basin geometry in the Late Miocene of the northern Apennines of Italy: the Montardone mélange     

Stefano Conti  Daniela Fontana  Claudio Corrado Lucente  Gian Andrea Pini 《International Journal of Earth Sciences》2014,103(1):281-295

The Montardone mélange (Mm) is a chaotic, block-in-matrix unit outcropping in the Montebaranzone syncline in the northern Apennines. The Mm occurs in the uppermost part of the Termina Fm, the Middle–Late Miocene interval of a succession deposited in a wedge-top slope basin (Epiligurian succession). The Mm is closely associated with bodies of authigenic carbonates, characterized by negative values of δ¹³C (from ?18.22 to ?39.05 ‰ PDB) and chemosynthetic benthic fauna (lucinid and vesicomyid bivalves). In this paper, we propose that the Mm is a mud volcano originated by the post-depositional reactivation and rising of a stratigraphically lower mud-rich mass transport body (Canossa–Val Tiepido sedimentary mélange or olistostrome) triggered by fluid overpressure. We base our conclusion on (1) the Mm pierces the entire Termina Fm and older Epiligurian units and represents the direct continuation of the underlying Canossa–Val Tiepido mélange; (2) the geometry and facies distribution of the Montebaranzone sandstone body, which are compatible with a confined basin controlled by the rising of the Mm; (3) the systematic presence of large-scale (lateral extension 300–400 m) seep-carbonates associated with the mélange, suggesting a persistent gas-enriched fluid vent from the ascending overpressured mud; (4) blocks and clasts sourced from the Mm, hosted by the authigenic carbonates, conveyed by ascending mud and gas-enriched fluids. The Mm represents one of the few fossil examples of reactivation of a basin-scale sedimentary mélange (olistostrome); a three-stage model showing mechanisms of Mm raising is proposed.  相似文献   

Hydrological Regime and Renewal Capacity of the Micro-tidal Lesina Lagoon,Italy   总被引：1，自引：0，他引：1  

Christian Ferrarin  Luca Zaggia  Elio Paschini  Tommaso Scirocco  Giuliano Lorenzetti  Marco Bajo  Pierluigi Penna  Matteo Francavilla  Raffaele D’Adamo  Stefano Guerzoni 《Estuaries and Coasts》2014,37(1):79-93

A multidisciplinary approach that combines field measurements, artificial neural networks, water balance analyses and hydrodynamic modelling was developed to investigate the water budget and renewal capacity of semi-closed coastal systems. The method was applied to the Lesina Lagoon, a micro-tidal lagoon in the southern Adriatic Sea (Italy). Surface water flux between the lagoon and the sea was determined by neural network prediction and used as input in the analysis. Strong seasonal variations in the water budget equation were predicted. Fresh water inputs estimated by the water balance analysis were used as forcing by a calibrated finite element model to describe the water circulation and transport time scale of the lagoon’s surface waters. The model highlighted the spatial heterogeneity of the renewal behaviour of the system, with a strong east–west water renewal time gradient. Knowledge of spatial distribution of water renewal times is crucial for understanding the lagoon’s renewal capacity and explaining the high spatial variability of the biogeochemistry of the Lesina Lagoon.  相似文献   

Terrestrial laser scanner and geomechanical surveys for the rapid evaluation of rock fall susceptibility scenarios   总被引：3，自引：1，他引：2  

Giovanni Gigli  Stefano Morelli  Simone Fornera  Nicola Casagli 《Landslides》2014,11(1):1-14

The primary objective of this paper is to present a semiautomatic procedure that, integrated with traditional methods, can be useful for a rapid definition of rock fall susceptibility scenarios with the purpose of civil protection. Due to its morphology (steep slopes and narrow valleys), regional seismicity, and rock mass characteristics, the Nera Valley (Valnerina, Umbria Region, Italy) is characterized by high rock fall risk. With the aim of covering a wide range of features and investigating the main advantages and drawbacks of the proposed approach, data collection (terrestrial laser scanning (TLS) and geomechanical surveys) was carried out at three different slopes. Detailed three-dimensional (3D) models were created to reconstruct the shape and volume of the most unstable blocks, to define the position of the main rock fall source areas, and to precisely distinguish the outcropping materials and the position of the elements at risk for reliable runout analyses. The proposed approach can be useful in supporting proper maintenance and land management programs both in ordinary and in emergency circumstances.  相似文献   

Observations of the temperature and polarization anisotropies with Boomerang 2003     

W.C. Jones  P.A.R. Ade  J.J. Bock  J.R. Bond  J. Borrill  A. Boscaleri  P. Cabella  C.R. Contaldi  B.P. Crill  P. de Bernardis  G. De Gasperis  A. de Oliveira-Costa  G. De Troia  G. Di Stefano  E. Hivon  A.H. Jaffe  T.S. Kisner  A.E. Lange  C.J. MacTavish  S. Masi  P.D. Mauskopf  A. Melchiorri  T.E. Montroy  P. Natoli  C.B. Netterfield  E. Pascale  F. Piacentini  D. Pogosyan  G. Polenta  S. Prunet  S. Ricciardi  G. Romeo  J.E. Ruhl  P. Santini  M. Tegmark  M. Veneziani  N. Vittorio   《New Astronomy Reviews》2006,50(11-12):945

The Boomerang experiment completed its final long duration balloon (LDB) flight over Antarctica in January 2003. The focal plane was upgraded to accommodate four sets of 145 GHz polarization sensitive bolometers (PSBs), identical to those to be flown on the Planck HFI instrument. Approximately, 195 hours of science observations were obtained during this flight, including 75 hours distributed over 1.84% of the sky and an additional 120 hours concentrated on a region covering 0.22% of the sky. We derive the angular power spectra of the cosmic microwave background (cmb) temperature and polarization anisotropies from these data. The temperature anisotropies are detected with high signal to noise on angular scales ranging from several degrees to 10 arcminutes. The curl-free (EE) component is detected at 4.8σ, and a two-sigma upper limit on the curl (BB) component of 8.6 μK² is obtained on scales corresponding to 0.5°. Both the temperature and polarization anisotropies are found to be consistent with a concordance ΛCDM cosmology that is seeded by adiabatic density perturbations. In addition to the cmb observations, Boomerang03 surveyed a 300 square degree region centered on the Galactic plane. These observations represent the first light for polarization sensitive bolometers, which are currently operational in two South-Pole based polarimeters, as well as Planck HFI, at frequencies ranging from 100 to 350 GHz (3 mm to 850 μm).  相似文献