Similarities and differences between the [WC 2] nucleus of NGC 5189 and the WO star Sand 4     

Vito Francesco Polcaro  Corinne Rossi  Roberto Viotti  Laura Norci 《Astrophysics and Space Science》1996,238(1):59-62

Long slit spectra of the planetary nebula NGC 5189 with its [WC2] type central object and the G2.4+1.4 wind bubble around the evolved Pop. I WO star Sand 4 were obtained in order to investigate the observable effects of different initial masses in stars with otherwise similar spectra. Our preliminary results of a comparative spectroscopic study of these two objects shows that the chemical composition of the two nebuale is completely different, even though their morphology is most probably quite similar. In addition, the PN appears much more chemically homogeneous. These features are clearly associated with the evolutionary paths of the stars.  相似文献   

A new version of the USLE‐MM for predicting bare plot soil loss at the Sparacia (South Italy) experimental site          下载免费PDF全文

Vincenzo Bagarello  Vito Ferro  Vincenzo Pampalone 《水文研究》2015,29(19):4210-4219

Improving empirical prediction of plot soil erosion at the event temporal scale has both scientific and practical importance. In this investigation, 492 runoff and soil loss data from plots of different lengths, λ (11 ≤ λ ≤ 44 m), and steepness, s (14.9 ≤ s ≤ 26.0%), established at the Sparacia experimental station, in Sicily, South Italy, were used to derive a new version of Universal Soil Loss Equation (USLE)‐MM model, by only assuming a value of one for the topographic length, L, and steepness, S, factors for λ = 22 m and s = 9%, respectively. An erosivity index equal to (Q_REI₃₀)^b1, Q_R and EI₃₀ being the runoff coefficient and the event rainfall erosivity index, respectively, with b₁ > 1 was found to be an appropriate choice for the Sparacia area. The specifically developed functions for L and S did not differ appreciably from other, more widely accepted relationships (maximum differences by a factor of 1.22 for L and 1.09 for S). The new version of the USLE‐MM performed particularly well for highly erosive events, because predicted soil loss differed by not more than a factor of 1.19 from the measured soil loss for measured values of more than 100 Mg ha^?1. The choice of the relationships to predict topographic effects on plot soil loss should not represent a point of particular concern in the application of the USLE‐MM in other environments. However, tests of the empirical approach should be carried out in other experimental areas in an attempt to develop analytical tools, usable at the event temporal scale, reasonably simple and of wide validity. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

A non‐extensive approach in investigating the seismicity of L’Aquila area (central Italy), struck by the 6 April 2009 earthquake (ML = 5.8)     

Luciano Telesca 《地学学报》2010,22(2):87-93

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Measuring rill erosion at plot scale by a drone‐based technology          下载免费PDF全文

Francesco Giuseppe Carollo  Costanza Di Stefano  Vito Ferro  Vincenzo Pampalone 《水文研究》2015,29(17):3802-3811

The traditional direct method (i.e. metric ruler and rillmeter) of monitoring rill erosion at plot scale is time consuming and invasive because it modifies the surface of the rilled area. Measuring rill features using a drone‐based technology is considered a non‐invasive method allowing a fast field relief. In the experimental Sparacia area a survey by a quadricopter Microdrones md4‐200 was carried out, and this relief allowed the generation of a Digital Elevation Model (DEM), with a mesh size of 1 cm and a resolution elevation equal to 2 mm, for three plots (L, G and C) affected by rill erosion. At first for the experimental L plot, which is 44 m long, the rill features were surveyed by a ‘manual’ method which was carried out by drawing on the PC screen the rill paths obtained by a visual orthophoto interpretation. This manual method was not applicable for the plots in which rills of limited depth occurred and were not detectable. Then, for both L plot and the other experimental plots having a length ranging from 22 to 44 m, an ‘automatic’ extraction method of rills from DEM was applied. Using an appropriate calculation routine, a vector coverage of transects orthogonal to the main flow direction (i.e. the maximum slope steepness path) was generated. The intersection of each plot DEM with the transect coverage allowed to obtain both the cross sections and the main rill morphological features. For the L plot the comparison between the rill morphological features obtained by the two different methods (manual, automatic) was carried out. Finally, the length–volume relationship and a dimensionless relationship proposed in literature were tested for all studied experimental plots. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

The volcanic and geothermally active Campi Flegrei caldera: an integrated multidisciplinary image of its buried structure     

M. Piochi  C. R. J. Kilburn  M. A. Di Vito  A. Mormone  A. Tramelli  C. Troise  G. De Natale 《International Journal of Earth Sciences》2014,103(2):401-421

The Campi Flegrei caldera in southern Italy is one of the greatest geohazard areas on Earth. Evidence of an active magmatic and geothermal system is provided by ongoing ground uplift, with volcano-tectonic and long-period (LP) seismicity, the persistent degassing of ~1500 tonnes of CO₂ per day, the presence of hot fumaroles at temperatures of 90–150 °C, brine-rich aquifers (with total dissolved solids up to 33 g l^?1) and high thermal gradients in the crust (with temperatures reaching 420 °C at 3,050 m b.s.l.). Since the 1940s, more than 100 exploratory boreholes have been drilled in the area to depths of 80–3,100 m by the Azienda Geologica Italiana Petroli (AGIP) and the Società Anonima Forze Endogene Napoletane (SAFEN). To date, however, no systematic reanalysis of the drilling data has been carried out, and the buried volcanic structure has not been updated using the most recent scientific results and previous findings. By integrating unpublished data from the AGIP and SAFEN reports with published information from geological, volcanological, petrological, petrophysical and geophysical studies, this paper presents an improved picture of the Campi Flegrei caldera that will be useful for volcanic hazard assessment and mitigation in the Naples area and for future research planning. The results suggest that intra-caldera activity has been influenced by how the magmatic system at depths greater than about 4 km has determined the transfer of magma, volatiles, and heat to the overlying geothermal system and, ultimately, to the surface. In particular, intriguing is that the most volcanically active central-eastern sector of the caldera, which is subject to intense bradyseismic ground movement and gas emission, coincides with a structurally delimited subsurface rock volume characterized by an uprising of the 100 °C isotherm, a deep water supply to the shallower aquifer, the early disappearance of secondary calcite, LP seismicity and high seismic S-wave attenuation. In this area, we also document evidence of repeated injection at depths of c. 1.5–3.0 km of isolated and small-volume batches of magma, where occurred their crystallization and degassing. Shallow intrusions and degassing of magma are thus identified as two of the key processes that drive unrest in Campi Flegrei.  相似文献   

Precipitable water evaluations from infrared sun‐photometric measurements analyzed using the atmospheric hygrometry technique     

Claudio Tomasi  Stefano Marani  Vito Vitale  Frank Wagner  Alessandra Cacciari  Angelo Lupi 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):734-749

Measurements of direct solar irradiance were taken employing 4 different sun‐photometers at near infrared wavelengths, suitable for use in atmospheric hygrometry. This technique utilising a set of spectral ratios, in and out of selected water vapour absorption bands, was applied to the measurements to obtain accurate evaluations of precipitable water. For all the hygrometric ratios given by the 4 sun‐photometers used at the 3 stations of Sagres, Monchique and Mt. Foia, during the CLEARCOLUMN experiment, we determined the calibration curves by correcting them for the Rayleigh scattering effects and, then, plotting the natural logarithms of such corrected ratios versus the square root of the water vapour mass present along the atmospheric slant path. The regression lines drawn for the various scatter diagrams were estimated to give evaluations of precipitable water with an uncertainty of less than 5%, 3% and 10% at the 3 stations, respectively. The calibration curves of the sun‐photometer located at the Sagres station were determined using the precipitable water evaluations obtained from the local radiosounding measurements taken on 5 clear‐sky days. Those of the sun‐photometers used at the Monchique and Mt. Foia stations were instead determined through intercomparison between subsets of measurements simultaneously taken with various instruments at Sagres and Mt. Foia. Using these calibration curves, we examined all the field measurements determining the time‐patterns of precipitable water at the 3 stations. During the period from 16 June to 25 July 1997, precipitable water was found to vary between 1.1 and 3.7 g cm⁻² at the Sagres station (with an accuracy within ±13%), between 1.0 and 2.8 g cm⁻² at Monchique (±11%) and between 0.8 and 3.0 g cm⁻² at the top of Mt. Foia (±26%).  相似文献   

Laboratory Studies on Silicates Relevant for the Physics of TNOs     

Brucato  John Robert  Strazzulla  Giovanni  Baratta  Giuseppe  Mennella  Vito  Colangeli  Luigi 《Earth, Moon, and Planets》2003,92(1-4):307-314

Silicates are one of the principal components present in Solar System objects.Silicates evolve in space modifying their physical properties according to theastronomical environments they go through. To characterise the nature of TNOsin the framework of the formation and evolution of the Solar System, experimentson structural transitions of silicates have been performed in the laboratoryto simulate some of the processing suffered by the dust. The infrared spectralproperties of possible silicate candidates thought to be present in TNOs have beenstudied. The results of thermal annealing of amorphous silicates and amorphisationof crystalline forsterite (pure-Mg olivine) by ion irradiation are presented. Theobservable properties of TNOs surfaces are inferred.  相似文献   

Comment on ‘Measuring the flow resistance of submerged grass’ by C. A. M. E. Wilson and M. S. Horritt,Hydrological Processes 16: 2589–2598     

Francesco Giuseppe Carollo  Vito Ferro 《水文研究》2005,19(2):533-539

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Investigating the time dynamics of monthly rainfall time series observed in northern Lebanon by means of the detrended fluctuation analysis and the Fisher-Shannon method     

Michele Lovallo  Amin Shaban  Talal Darwich  Luciano Telesca 《Acta Geophysica》2013,61(6):1538-1555

We investigate the time dynamics of monthly rainfall series intermittently recorded on seven climatic stations in northern Lebanon from 1939 to 2010 using the detrending fluctuation analysis (DFA) and the Fisher-Shannon (FS) method. The DFA is employed to study the scaling properties of the series, while the FS method to analyze their order/organization structure. The obtained results indicate that most all the stations show a significant persistent behavior, suggesting that the dynamics of the rainfall series is governed by positive feedback mechanisms. Furthermore, we found that the Fisher Information Measure (the Shannon entropy power) seems to decrease (increase) with the height of the rain gauge; this indicates that the rainfall series appear less organized and less regular for higher-located stations. Such findings could be useful for a better comprehension of the climatic regimes governing northern Lebanon.  相似文献   

Comparing theoretically supported rainfall‐runoff erosivity factors at the Sparacia (South Italy) experimental site          下载免费PDF全文

Vincenzo Bagarello  Costanza Di Stefano  Vito Ferro  Vincenzo Pampalone 《水文研究》2018,32(4):507-515

Interpreting rainfall‐runoff erosivity by a process‐oriented scheme allows to conjugate the physical approach to soil loss estimate with the empirical one. Including the effect of runoff in the model permits to distinguish between detachment and transport in the soil erosion process. In this paper, at first, a general definition of the rainfall‐runoff erosivity factor REF_e including the power of both event runoff coefficient Q_R and event rainfall erosivity index EI₃₀ of the Universal Soil Loss Equation (USLE) is proposed. The REF_e factor is applicable to all USLE‐based models (USLE, Modified USLE [USLE‐M] and Modified USLE‐M [USLE‐MM]) and it allows to distinguish between purely empirical models (e.g., Modified USLE‐M [USLE‐MM]) and those supported by applying theoretical dimensional analysis and self‐similarity to Wischmeier and Smith scheme. This last model category includes USLE, USLE‐M, and a new model, named USLE‐M based (USLE‐MB), that uses a rainfall‐runoff erosivity factor in which a power of runoff coefficient multiplies EI₃₀. Using the database of Sparacia experimental site, the USLE‐MB is parameterized and a comparison with soil loss data is carried out. The developed analysis shows that USLE‐MB (characterized by a Nash–Sutcliffe Efficiency Index NSEI equal to 0.73 and a root mean square error RMSE = 11.7 Mg ha^?1) has very similar soil loss estimate performances as compared with the USLE‐M (NSEI = 0.72 and RMSE = 12.0 Mg ha^?1). However, the USLE‐MB yields a maximum discrepancy factor between predicted and measured soil loss values (176) that is much lower than that of USLE‐M (291). In conclusion, the USLE‐MB should be preferred in the context of theoretically supported USLE type models.  相似文献