Topical issue on EChO - the Exoplanet Characterisation Observatory     

Giovanna Tinetti  Pierre Drossart 《Experimental Astronomy》2015,40(2-3):327-328

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The formation of tidal sand waves: Fully three-dimensional versus shallow water approaches     

Paolo Blondeaux  Giovanna Vittori 《Continental Shelf Research》2011,31(9):990-996

Tidal sand waves, also named tidal dunes, are large scale bedforms generated by the growth of perturbations of the sea bottom driven by tidal currents. Indeed, the interaction of an oscillatory tidal current with a bottom waviness gives rise to steady recirculating cells which tend to drag the sediment from the troughs towards the crests of the bottom perturbation. The net motion of the sediment towards the crests is opposed by gravity force and the growth of the perturbation is controlled by a balance between these two effects. In the literature, to determine the conditions which lead to the formation of sand waves and to determine the characteristics of the bedforms generated by this instability mechanism, both fully three-dimensional and shallow water approaches are employed. The shallow water approach is computationally less expensive than the fully three-dimensional one but, in many cases, it might be less accurate. This paper compares the quantitative predictions obtained by means of the two approaches and quantifies the range of the parameters such that the shallow water approximation provides reliable predictions.  相似文献   

FLaIR and SUSHI: two mathematical models for early warning of landslides induced by rainfall   总被引：8，自引：7，他引：1  

Giovanna Capparelli  Pasquale Versace 《Landslides》2011,8(1):67-79

The development of Early Warning Systems in recent years has assumed an increasingly important role in landslide risk mitigation. In this context, the main topic is the relationship between rainfall and the incidence of landslides. In this paper, we focus our attention on the analysis of mathematical models capable of simulating triggering conditions. These fall into two broad categories: hydrological models and complete models. Generally, hydrological models comprise simple empirical relationships linking antecedent precipitation to the time that the landslide occurs; the latter consist of more complex expressions that take several components into account, including specific site conditions, mechanical, hydraulic and physical soil properties, local seepage conditions, and the contribution of these to soil strength. In a review of the most important models proposed in the technical and international literature, we have outlined their most meaningful and salient aspects. In particular, the Forecasting of Landslides Induced by Rainfall (FLaIR) and the Saturated Unsaturated Simulation for Hillslope Instability (SUSHI) models, developed by the authors, are discussed. FLaIR is a hydrological model based on the identification of a mobility function dependent on landslide characteristics and antecedent rainfall, correlated to the probability of a slide occurring. SUSHI is a complete model for describing hydraulic phenomena at slope scale, incorporating Darcian saturated flow, with particular emphasis on spatial–temporal changes in subsoil pore pressure. It comprises a hydraulic module for analysing the circulation of water from rainfall infiltration in saturated and nonsaturated layers in non-stationary conditions and a geotechnical slope stability module based on Limit Equilibrium Methods. The paper also includes some examples of these models’ applications in the framework of early warning systems in Italy.  相似文献   

Methods and models for dealing with spatial variability in soil and rock characterisation: design,management and related hazards     

Giovanna Vessia  Wojciech Pula 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2015,9(4)

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Mycobiota associated with the rhodophyte alien species Asparagopsis taxiformis (Delile) Trevisan de Saint‐Léon in the Mediterranean Sea          下载免费PDF全文

Laura Garzoli  Giorgio Gnavi  Giovanna C. Varese  Anna M. Picco 《Marine Ecology》2015,36(4):959-968

This study is the first to investigate and characterize the mycobiota associated with the alien species Asparagopsis taxiformis, a rhodophyte classified as one of the ‘100 worst invasive species’ in the Mediterranean Sea by the Hellenic Center for Marine Research, as it threatens biodiversity. Fungal endophyte and epiphyte communities were investigated on algal specimens from two sampling sites on the island of Linosa (Marine Protected Area Isole Pelagie, Italy). 87% of the 24 specimens that were analysed for epiphytes displayed a microfungal colonization. No endophytes were found. Only a small amount of microfungi was found to be associated with this alga. Only five fungal taxa were isolated; two of which are sporadically associated with the alga, while three, Eurotium rubrum, Cladosporium cladosporioides and Cladosporium pseudocladosporioides, seem to be related to A. taxiformis. This scarcity could be related to algal chemical composition.  相似文献   

Centropages typicus (Crustacea,Copepoda) reacts to volatile compounds produced by planktonic algae          下载免费PDF全文

Chingoileima Maibam  Patrick Fink  Giovanna Romano  Maria Cristina Buia  Emanuela Butera  Valerio Zupo 《Marine Ecology》2015,36(3):819-834

Volatile organic compounds (VOCs) may play the role of infochemicals and trigger chemotaxis and ecologically relevant responses in freshwater and marine invertebrates. Aquatic grazers use these signals as chemical cues to trace the presence of their food or to detect their predators. However, detailed data are still needed to fully understand the role of these relationships in marine plankton. We investigated the ability of the copepod Centropages typicus to perceive the odour of three planktonic diatoms (Skeletonema marinoi, Pseudonitzschia delicatissima and Chaetoceros affinis) and a dinoflagellate (Prorocentrum minimum). This information is ecologically relevant for orientation, habitat selection, predator avoidance and communication. In addition, as the pH of the medium influences the perception of chemical cues in aquatic environments, we tested the effect of seawater acidification resulting from increasing levels of CO₂, and its influences on the olfactory reactions of copepods. For this reason, our tests were repeated in normal (pH 8.10) and acidified (pH 7.76) seawater in order to simulate future ocean acidification scenarios. Using replicated chemokinetic assays we demonstrated that VOCs produced by Ps. delicatissima and Pr. minimum attract copepods at normal pH, but this effect is lowered in acidified water. By contrast, the odour of S. marinoi mainly induces a reaction of repulsion, but in acidified water and at higher concentrations this toxic diatom becomes attractive for copepods. Our experiments demonstrate, for the first time, that copepods are sensitive to the volatile compounds contained in various microalgae; VOCs prompt chemokinesis according to algal species and odour concentrations. However, seawater acidification induces changes in copepods' perception of odours. These findings highlight the sensitivity of chemically mediated interactions to global changes  相似文献   

Depositional evolution of a lower Paleozoic portion of the Southalpine domain: the Mt. Pizzul area (Carnic Alps,Italy)     

Monica Pondrelli  Carlo Corradini  Luca Simonetto  Maria Giovanna Corriga  Erika Kido  Angelo Mossoni  Claudia Spalletta  Thomas J. Suttner  Nicola Carta 《International Journal of Earth Sciences》2015,104(1):147-178

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Geochronological study of zircons from continental crust rocks in the Frido Unit (southern Apennines)     

Salvatore Laurita  Giacomo Prosser  Giovanna Rizzo  Antonio Langone  Massimo Tiepolo  Alessandro Laurita 《International Journal of Earth Sciences》2015,104(1):179-203

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Quaternary evolution of the Lucania Apennine thrust front area (Southern Italy), and its relations with the kinematics of the Adria Plate boundaries     

Marco Bonini  Federico Sani  Giovanna Moratti  Marco G. Benvenuti 《Journal of Geodynamics》2011,51(2-3):125-140

We examine the structural characteristics and the tectonic evolution of some key areas along the thrust front of the Lucania sector of the Southern Apennines, which also represents the southwestern boundary of the Adria Plate. The results of our study have allowed the identification of a complex tectonic history manifested by the presence of structural elements compatible with different stress fields. Particularly, during the Pleistocene the area experienced a transition from a compressional setting, characterised by NE-ENE shortening, to a post-Middle Pleistocene strike-slip/extensional phase controlled by NE-ENE-directed lateral extension associated with a horizontal NW-NNW-trending σ₁ axis. Roughly coaxial transitional stress fields apparently accompanied the progression between these two main regimes. This major change in tectonic setting can be framed into the fragmentation processes of the Adriatic Plate. We propose that the Mid-Adriatic Ridge, a WNW-ESE-trending belt of inverted Mesozoic grabens underwater the Adriatic Sea, has increasingly accommodated the NNW-directed Africa-Adria convergence giving the way to the Africa shortening to propagate into the Lucania Apennines. Furthermore, the comparison with GPS data suggests the existence of an important deep-seated tectonic boundary beneath the Apennines. This element is expected to focus seismicity and may represent an important discontinuity fragmenting Adria.  相似文献   

The thermal behaviour of heulandites: A structural study of the dehydration of Nadap heulandite     

Prof. A. Alberti  Dr. Giovanna Vezzalini 《Mineralogy and Petrology》1983,31(3-4):259-270

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