Water residence time as a driving force of zooplankton structure and succession     

Ulrike Obertegger  Giovanna Flaim  Maria Giovanna Braioni  Ruben Sommaruga  Flavio Corradini  Andrea Borsato 《Aquatic Sciences - Research Across Boundaries》2007,69(4):575-583

  相似文献   

A Cretaceous carbonate delta drift in the Montagna della Maiella,Italy     

Gregor P. Eberli  Daniel Bernoulli  Adam Vecsei  Rizky Sekti  Mark Grasmueck  Thomas Lüdmann  Flavio S. Anselmetti  Maria Mutti  Giovanna Della Porta 《Sedimentology》2019,66(4):1266-1301

The Upper Cretaceous (Campanian–Maastrichtian) bioclastic wedge of the Orfento Formation in the Montagna della Maiella, Italy, is compared to newly discovered contourite drifts in the Maldives. Like the drift deposits in the Maldives, the Orfento Formation fills a channel and builds a Miocene delta‐shaped and mounded sedimentary body in the basin that is similar in size to the approximately 350 km² large coarse‐grained bioclastic Miocene delta drifts in the Maldives. The composition of the bioclastic wedge of the Orfento Formation is also exclusively bioclastic debris sourced from the shallow‐water areas and reworked clasts of the Orfento Formation itself. In the near mud‐free succession, age‐diagnostic fossils are sparse. The depositional textures vary from wackestone to float‐rudstone and breccia/conglomerates, but rocks with grainstone and rudstone textures are the most common facies. In the channel, lensoid convex‐upward breccias, cross‐cutting channelized beds and thick grainstone lobes with abundant scours indicate alternating erosion and deposition from a high‐energy current. In the basin, the mounded sedimentary body contains lobes with a divergent progradational geometry. The lobes are built by decametre thick composite megabeds consisting of sigmoidal clinoforms that typically have a channelized topset, a grainy foreset and a fine‐grained bottomset with abundant irregular angular clasts. Up to 30 m thick channels filled with intraformational breccias and coarse grainstones pinch out downslope between the megabeds. In the distal portion of the wedge, stacked grainstone beds with foresets and reworked intraclasts document continuous sediment reworking and migration. The bioclastic wedge of the Orfento Formation has been variously interpreted as a succession of sea‐level controlled slope deposits, a shoaling shoreface complex, or a carbonate tidal delta. Current‐controlled delta drifts in the Maldives, however, offer a new interpretation because of their similarity in architecture and composition. These similarities include: (i) a feeder channel opening into the basin; (ii) an excavation moat at the exit of the channel; (iii) an overall mounded geometry with an apex that is in shallower water depth than the source channel; (iv) progradation of stacked lobes; (v) channels that pinch out in a basinward direction; and (vi) smaller channelized intervals that are arranged in a radial pattern. As a result, the Upper Cretaceous (Campanian–Maastrichtian) bioclastic wedge of the Orfento Formation in the Montagna della Maiella, Italy, is here interpreted as a carbonate delta drift.  相似文献   

Shakemaps uncertainties and their effects in the post-seismic actions for the 2012 Emilia (Italy) earthquakes     

Giovanna Cultrera  Licia Faenza  Carlo Meletti  Vera D’Amico  Alberto Michelini  Alessandro Amato 《Bulletin of Earthquake Engineering》2014,12(5):2147-2164

The May 20, 2012, Emilia Ml 5.9 earthquake was followed by some major aftershocks, well recorded by a large number of temporary stations that were installed to monitor the sequence. These additional recordings allowed us a thorough testing of the performance of the ShakeMap—a procedure designed to provide rapid information on the experienced ground motion. We found that the shakemaps for the May 29, 2012, Ml 5.8 earthquake, obtained using the permanent stations only, underestimate significantly the ground motion computed with the highest station density, especially for PSA at long periods (T \(=\) 3.0 s). This low-frequency motion is controlled primarily by the surface waves recorded in the Po plain: the observed site effects are likely not accounted properly by the site correction coefficient based on Vs30 as implemented in the ShakeMap procedure. The shakemaps determined during the seismic sequence have been included in an Italian national law that was passed after the 2012 earthquake. According to this law, the factories safety verifications were bound to the comparison between the shakemaps and the design acceleration required by the current national seismic code. We then decide to appraise the impact of the shakemap accuracy on the law provisions. Following the law recommendations, we have estimated the possible errors resulting from the incomplete evaluation of the ground shaking: our results show that, if the complete dataset were available at the time of the law approval, the number of buildings for which the safety check was required would have been significantly smaller.  相似文献   

Bayesian logistic regression for presence-only data     

Fabio Divino  Natalia Golini  Giovanna Jona Lasinio  Antti Penttinen 《Stochastic Environmental Research and Risk Assessment (SERRA)》2015,29(6):1721-1736

Presence-only data are referred to situations in which a censoring mechanism acts on a binary response which can be partially observed only with respect to one outcome, usually denoting the presence of an attribute of interest. A typical example is the recording of species presence in ecological surveys. In this work a Bayesian approach to the analysis of presence-only data based on a two levels scheme is presented. A probability law and a case-control design are combined to handle the double source of uncertainty: one due to censoring and the other one due to sampling. In the paper, through the use of a stratified sampling design with non-overlapping strata, a new formulation of the logistic model for presence-only data is proposed. In particular, the logistic regression with linear predictor is considered. Estimation is carried out with a new Markov Chain Monte Carlo algorithm with data augmentation, which does not require the a priori knowledge of the population prevalence. The performance of the new algorithm is validated by means of extensive simulation experiments using three scenarios and comparison with optimal benchmarks. An application to data existing in literature is reported in order to discuss the model behaviour in real world situations together with the results of an original study on termites occurrences data.  相似文献   

Effects of different boundary conditions on the simulation of groundwater flow in a multi-layered coastal aquifer system (Taranto Gulf,southern Italy)     

Giovanna De Filippis  Laura Foglia  Mauro Giudici  Steffen Mehl  Stefano Margiotta  Sergio L. Negri 《Hydrogeology Journal》2017,25(7):2123-2138

The evaluation of the accuracy or reasonableness of numerical models of groundwater flow is a complex task, due to the uncertainties in hydrodynamic properties and boundary conditions and the scarcity of good-quality field data. To assess model reliability, different calibration techniques are joined to evaluate the effects of different kinds of boundary conditions on the groundwater flow in a coastal multi-layered aquifer in southern Italy. In particular, both direct and indirect approaches for inverse modeling were joined through the calibration of one of the most uncertain parameters, namely the hydraulic conductivity of the karst deep hydrostratigraphic unit. The methodology proposed here, and applied to a real case study, confirmed that the selection of boundary conditions is among the most critical and difficult aspects of the characterization of a groundwater system for conceptual analysis or numerical simulation. The practical tests conducted in this study show that incorrect specification of boundary conditions prevents an acceptable match between the model response to the hydraulic stresses and the behavior of the natural system. Such effects have a negative impact on the applicability of numerical modeling to simulate groundwater dynamics in complex hydrogeological situations. This is particularly important for management of the aquifer system investigated in this work, which represents the only available freshwater resource of the study area, and is threatened by overexploitation and saltwater intrusion.  相似文献   

Sea gravity data in the Gulf of Naples. A contribution to delineating the structural pattern of the Phlegraean Volcanic District     

Giovanna Berrino  Gennaro Corrado  Umberto Riccardi 《Journal of Volcanology and Geothermal Research》2008

Bathymetric and gravity surveys were carried out from 1988 to 1994, in the Gulf of Naples (Southern Italy) to offshore extend the already existing Bouguer anomaly map. In order to improve the knowledge of the structural setting beneath the active Neapolitan volcanoes (Vesuvio, Campi Flegrei and Ischia), 862 stations were surveyed within the isobath of 400 m; at the same time, and about 2000 on-land gravity values were also collected. A new Bouguer anomaly map spanning the whole volcanic region was drawn from the final data set. Gravity anomalies were referred to the new absolute gravity station in Naples and computed according to 1980 Geodetic Reference System. Finally, a density value of 2200 kg/m³ was used in the computation of the Bouguer and terrain effects. We carried out the inversion of the gravity anomalies adopting a 2.5-D modelling along selected profiles crossing the investigated area. The interpretative models were constrained to data obtained from deep wells and other geophysical investigations.  相似文献   

FREEWAT,a Free and Open Source,GIS‐Integrated,Hydrological Modeling Platform          下载免费PDF全文

Laura Foglia  Iacopo Borsi  Steffen Mehl  Giovanna De Filippis  Massimiliano Cannata  Enric Vasquez‐Suñe  Rotman Criollo  Rudy Rossetto 《Ground water》2018,56(4):521-523

  相似文献   

Joint deconvolution of building and downhole seismic recordings: an application to three test cases     

Bojana Petrovic  Stefano Parolai  Giovanna Pianese  S. Umit Dikmen  Bolot Moldobekov  Sagynbek Orunbaev  Roberto Paolucci 《Bulletin of Earthquake Engineering》2018,16(2):613-641

In this study, the joint deconvolution is applied to recordings of three test cases located in the cities of Bishkek, Kyrgyzstan, Istanbul, Turkey, and Mexico City, Mexico. Each test case consists of a building equipped with sensors and a nearby borehole installation in order to investigate different cases of coupling (impedance contrasts) between the building and the soil by analyzing the wave propagation through the building-soil-layers, and hence resolving the soil–structure-interactions. The three installations considering different dynamic characteristics of buildings and soil, and thus, different building-soil couplings, are investigated. The seismic input (i.e., the part of the wave field containing only the up-going waves after removing all down-going waves) and the part of the wave field that is associated with the waves radiated back from the building are separated by using the constrained deconvolution. The energy being radiated back from the building to the soil has been estimated for the three test cases. The values obtained show that even at great depths (and therefore distances), the amount of wave field radiated back by the building to the soil is significant (e.g., for the Bishkek case, at 145 m depth, 10% of the estimated real input energy is expected to be emitted back from the building; for Istanbul at 50 m depth, the value is also 10–15% of the estimated real input energy while for Mexico City at 45 m depth, it is 25–65% of the estimated real input energy). Such results confirm the active role of buildings in shaping the wave field.  相似文献   

Site-aspect influence on climate sensitivity over time of a high-altitude Pinus cembra tree-ring network   总被引：1，自引：0，他引：1  

Giovanni Leonelli  Manuela Pelfini  Giovanna Battipaglia  Paolo Cherubini 《Climatic change》2009,96(1-2):185-201

Recently a divergence between tree-ring parameters from temperature-limited environments and temperature records has been observed worldwide but comprehensive explanations are still lacking. From a dendroclimatic analysis performed on a high-altitude tree-ring network of Pinus cembra (L.) in the Central Italian Alps we found that site aspect influences non-stationary growth-climate relationships over time. A general increasing divergence between ring width and the summer temperature record (J–A) has been observed especially for chronologies from SW-facing slopes, whereas chronologies from N-facing sites showed stable relationships over time. The monthly analysis revealed that the decrease in sensitivity was mostly accounted for by the changes in the relationships with June temperature (decreasing correlations especially for S- and W-facing site chronologies), whereas trees from N-facing sites showed an increasing sensitivity to July temperatures. Our data suggest that at high altitudes, low temperatures at the beginning of the growing season no longer limit growth. We also found that our temperature-sensitive trees did not linearly respond in radial growth to the extreme heat event of summer 2003, and formed an annual ring of average width, resulting in a strong divergence from the temperature record. Our findings underline the importance of site ecology for tree-ring based climate reconstructions using temperature-sensitive ring-width chronologies, and may help in solving the ‘divergence problem’.  相似文献   

Observations of the Ca <Emphasis Type="SmallCaps">ii</Emphasis> IR Triplet in High Luminosity Quasars: Exploring the Sample     

Mary Loli Martínez-Aldama  Paola Marziani  Deborah Dultzin  Jack W. Sulentic  Alessandro Bressan  Yang Chen  Giovanna M. Stirpe 《Journal of Astrophysics and Astronomy》2015,36(4)

We present a new spectroscopic sample of 11 quasars at intermediate redshift observed with the Infrared Spectrometer and Array Camera (ISAAC) on the ESO Very Large Telescope (VLT), covering O i λ8446 and the Ca ii triplet 8498, 8542, 8662. The new observations – that supplement the sample presented by Martínez-Aldama et al. (2015) – allow us to confirm the constraints on physical conditions and location of the region emitting the low ionization lines, as well as the relation between Ca ii and Fe ii.  相似文献