Morphometric indices as indicators of tectonic,fluvial and karst processes in calcareous drainage basins,South Menorca Island,Spain     

Francesca S. Segura  Josep E. Pardo‐Pascual  Vicenç M. Rosselló  Joan J. Fornós  Bernadí Gelabert 《地球表面变化过程与地形》2007,32(13):1928-1946

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Effects of clogging on stream macroinvertebrates: An experimental approach     

Tiziano Bo  Giorgio Malacarne  Massimo Pessino  Francesca Sgariboldi 《Limnologica》2007,37(2):186-192

The influence of streambed sediment clogging on macroinvertebrate communities was investigated in the Lemme creek (NW Italy). To assess how fine sediment accumulation can influence the colonisation process and community composition of macroinvertebrates, we placed 48 traps in the riverbed. The traps consisted of boxes built with metal net (mesh 1 cm, height 15 cm, sides 5 cm) covered with nylon net except for the apex, allowing access exclusively from the top. We created four trap types filled with 100% gravel, 30% sand and 70% gravel, 70% sand and 30% gravel and 100% sand. After 20 and 40 days, we removed 6 traps/type. Macroinvertebrates rapidly colonised the traps, as we found no significant community differences between the two removal dates. Among the four trap types, we found significant differences in taxa number and abundance, which both decreased with increasing clogging. Thus, our study supports the hypothesis that clogging and the accumulation of fine substratum elements strongly affects benthic stream communities.  相似文献   

Circulation in a Southern Italy coastal basin: Modelling and field measurements     

Francesca De Serio  Daniela Malcangio  Michele Mossa 《Continental Shelf Research》2007

The purpose of the present work is to study the hydrodynamic aspects in the Mar Piccolo, a coastal basin located on the northern side of the Gulf of Taranto in the Ionian Sea (Italy), by means of mathematical modelling and field measurements. The latter were assessed during three surveys carried out in the spring–summer of 2002. Collected data have been utilized as input by the 3-D Princeton Ocean Model, which is a sigma coordinate, free surface ocean model which was developed in the late 1970s by Blumberg and Mellor. Simulations in baroclinic condition were forced by a homogeneous and stationary wind field, a simple tidal wave, a constant outflow and vertical stratification of temperature and salinity. A comparison was made between the mathematical modelling results and the field measurements collected during the surveys, in terms of velocity. It was observed that during small tides, when the wind effect prevails over the stratification effect, the best model results were obtained for the most superficial layer and that superficial patterns reproduced by the model are more sensitive to wind direction than to stratification. On the contrary, when the wind effect decreases or the thermohaline effect rises, best results occurred in deeper layers.  相似文献   

Heavy metals in surficial coastal sediments of the Ligurian Sea   总被引：1，自引：0，他引：1  

Bertolotto RM  Tortarolo B  Frignani M  Bellucci LG  Albanese S  Cuneo C  Alvarado-Aguilar D  Picca MR  Gollo E 《Marine pollution bulletin》2005,50(3):348-356

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Reply to the comment by G. Ventura, G. Vilardo, and P. P. Bruno     

G. Rolandi  F. Bellucci  M. Cortini 《Mineralogy and Petrology》2004,82(1-2):159-159

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Blue straggler production in globular clusters     

Melvyn B. Davies  Giampaolo Piotto  Francesca De Angeli 《Monthly notices of the Royal Astronomical Society》2004,349(1):129-134

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Photochemical evolution of elliptical galaxies – II. The impact of merging-induced starbursts     

Antonio Pipino  Francesca Matteucci 《Monthly notices of the Royal Astronomical Society》2006,365(4):1114-1122

The effects of late gas accretion episodes and subsequent merger-induced starbursts on the photochemical evolution of elliptical galaxies are studied and compared to the picture of galaxy formation occurring at high redshift with a unique and intense starburst modulated by a very short infall, as suggested by Pipino and Matteucci in Paper I. By means of the comparison with the colour–magnitude relations (CMRs) and the  [〈Mg/Fe〉 _V ]–σ  relation observed in ellipticals, we conclude that either bursts involving a gas mass comparable to the mass already transformed into stars during the first episode of star formation (SF) and occurring at any redshift, or bursts occurring at low redshift (i.e. z ≤ 0.2) and with a large range of accreted mass, are ruled out. These models fail in matching the above relations even if the initial infalling hypothesis is relaxed, and the galaxies form either by means of more complicated SF histories or by means of the classical monolithic model. On the other hand, galaxies accreting a small amount of gas at high redshift (i.e. z ≥ 3) produce a spread in the model results, with respect to the best model of Paper I, which is consistent with the observational scatter of the CMRs, although there is only marginal agreement with the  [〈Mg/Fe〉 _V ]–σ  relation. Therefore, only small perturbations to the standard scenario seem to be allowed. We stress that the strongest constraints to galaxy-formation mechanisms are represented by the chemical abundances, whereas the colours can be reproduced under several different hypotheses.  相似文献   

Large amplification of ground motion at rock sites within a fault zone in Nocera Umbra (central Italy)   总被引：2，自引：1，他引：1  

F. Marra  R. Azzara  F. Bellucci  A. Caserta  G. Cultrera  G. Mele  B. Palombo  A. Rovelli  E. Boschi 《Journal of Seismology》2000,4(4):543-554

During the two mainshocks of September 26, 1997 inthe Umbria-Marche border a strong-motion accelerographrecorded peak ground accelerations as large as 0.6 g,approximately, in the town of Nocera Umbra, atdistances of 10 to 15 km from the epicentres. Thisvalue is significantly larger than expected on thebasis of the usual regressions with magnitude anddistance. A broad-band amplification up to a factor of10 was consistently estimated in previous papers,using both weak and strong motion data recorded at theaccelerograph site during local moderate earthquakes.To study the cause of this amplification we deployedsix seismologic stations across the tectonic contactbetween the Ceno-Mesozoic limestone and the Mesozoicmarly sandstone where the accelerograph is installed.Seismograms of 21 shallow aftershocks in the magnituderange from 2.2 to 4.0 and a subcrustal M_w = 5.3event are analysed. Regardless of epicentre location,waveforms show a large complexity in an approximately200 m wide band adjacent to the tectonic contact. Thisis interpreted as the effect of trapped waves in thehighly fractured, lower velocity materials within thefault zone.  相似文献   

Estimating runoff from a glacierized catchment using natural tracers in the semi‐arid Andes cordillera          下载免费PDF全文

Maximiliano Rodriguez  Nils Ohlanders  Francesca Pellicciotti  Mark W. Williams  James McPhee 《水文研究》2016,30(20):3609-3626

This paper presents a methodology for hydrograph separation in mountain watersheds, which aims at identifying flow sources among ungauged headwater sub‐catchments through a combination of observed streamflow and data on natural tracers including isotope and dissolved solids. Daily summer and bi‐daily spring season water samples obtained at the outlet of the Juncal River Basin in the Andes of Central Chile were analysed for all major ions as well as stable water isotopes, δ¹⁸O and δD. Additionally, various samples from rain, snow, surface streams and exfiltrating subsurface water (springs) were sampled throughout the catchment. A principal component analysis was performed in order to address cross‐correlation in the tracer dataset, reduce the dimensionality of the problem and uncover patterns of variability. Potential sources were identified in a two‐component U‐space that explains 94% of the observed tracer variability at the catchment outlet. Hydrograph separation was performed through an Informative‐Bayesian model. Our results indicate that the Juncal Norte Glacier headwater sub‐catchment contributed at least 50% of summer flows at the Juncal River Basin outlet during the 2011–2012 water year (a hydrologically dry period in the Region), even though it accounts for only 27% of the basin area. Our study confirms the value of combining solute and isotope information for estimating source contributions in complex hydrologic systems, and provides insights regarding experimental design in high‐elevation semi‐arid catchments. The findings of this study can be useful for evaluating modelling studies of the hydrological consequences of the rapid decrease in glacier cover observed in this region, by providing insights into the origin of river water in basins with little hydrometeorological information. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Assessing rainfall–runoff models for the management of Lake Verbano     

Francesca Pianosi  Giovanni Ravazzani 《水文研究》2010,24(22):3195-3205

Growing human pressure and potential change in precipitation pattern induced by climate change require a more efficient and sustainable use of water resources. Hydrological models can provide a fundamental contribution to this purpose, especially as increasing availability of meteorological data and forecast allows for more accurate runoff predictions. In this article, two models are presented for describing the flow formation process in a sub‐alpine catchment: a distributed parameter, physically based model, and a lumped parameter, empirical model. The scope is to compare the two modelling approaches and to assess the impact of hydrometeorological information, either observations or forecast, on water resources management. This is carried out by simulating the real‐time management of the regulated lake that drains the catchment, using the inflow predictions provided by the two models. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献