Seismic source characterization of the Alpine foreland in the context of a probabilistic seismic hazard analysis by PEGASOS Expert Group 1 (EG1a)   总被引：1，自引：0，他引：1  

Stefan M. Schmid  Dario Slejko 《Swiss Journal of Geoscience》2009,102(1):121-148

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Oxygen in the Earth's core: a first-principles study     

Dario Alf  G. David Price  Michael J. Gillan 《Physics of the Earth and Planetary Interiors》1999,110(3-4):191-210

First-principles electronic structure calculations based on DFT have been used to study the thermodynamic, structural and transport properties of solid solutions and liquid alloys of iron and oxygen at Earth's core conditions. Aims of the work are to determine the oxygen concentration needed to account for the inferred density in the outer core, to probe the stability of the liquid against phase separation, to interpret the bonding in the liquid, and to find out whether the viscosity differs significantly from that of pure liquid iron at the same conditions. It is shown that the required concentration of oxygen is in the region 25–30 mol%, and evidence is presented for phase stability at these conditions. The Fe/O bonding is partly ionic, but with a strong covalent component. The viscosity is lower than that of pure liquid iron at Earth's core conditions. It is shown that earlier first-principles calculations indicating very large enthalpies of formation of solid solutions may need reinterpretation, since the assumed crystal structures are not the most stable at the oxygen concentration of interest.  相似文献   

Stormwater plume detection by MODIS imagery in the southern California coastal ocean     

Nikolay P. Nezlin  Paul M. DiGiacomo  Dario W. Diehl  Burton H. Jones  Scott C. Johnson  Michael J. Mengel  Kristen M. Reifel  Jonathan A. Warrick  Menghua Wang 《Estuarine, Coastal and Shelf Science》2008

Stormwater plumes in the southern California coastal ocean were detected by MODIS-Aqua satellite imagery and compared to ship-based data on surface salinity and fecal indicator bacterial (FIB) counts collected during the Bight'03 Regional Water Quality Program surveys in February–March of 2004 and 2005. MODIS imagery was processed using a combined near-infrared/shortwave-infrared (NIR-SWIR) atmospheric correction method, which substantially improved normalized water-leaving radiation (nLw) optical spectra in coastal waters with high turbidity. Plumes were detected using a minimum-distance supervised classification method based on nLw spectra averaged within the training areas, defined as circular zones of 1.5–5.0-km radii around field stations with a surface salinity of S < 32.0 (“plume”) and S > 33.0 (“ocean”). The plume optical signatures (i.e., the nLw differences between “plume” and “ocean”) were most evident during the first 2 days after the rainstorms. To assess the accuracy of plume detection, stations were classified into “plume” and “ocean” using two criteria: (1) “plume” included the stations with salinity below a certain threshold estimated from the maximum accuracy of plume detection; and (2) FIB counts in “plume” exceeded the California State Water Board standards. The salinity threshold between “plume” and “ocean” was estimated as 32.2. The total accuracy of plume detection in terms of surface salinity was not high (68% on average), seemingly because of imperfect correlation between plume salinity and ocean color. The accuracy of plume detection in terms of FIB exceedances was even lower (64% on average), resulting from low correlation between ocean color and bacterial contamination. Nevertheless, satellite imagery was shown to be a useful tool for the estimation of the extent of potentially polluted plumes, which was hardly achievable by direct sampling methods (in particular, because the grids of ship-based stations covered only small parts of the plumes detected via synoptic MODIS imagery). In most southern California coastal areas, the zones of bacterial contamination were much smaller than the areas of turbid plumes; an exception was the plume of the Tijuana River, where the zone of bacterial contamination was comparable with the zone of plume detected by ocean color.  相似文献   

UBV lightcurves of asteroid 433 Eros     

E.F. Tedesco 《Icarus》1976,28(1):21-28

UBV photometry and lightcurves of Eros were obtained on nine dates between October 1974 and March 1975. The absolute V magnitude at photometric maximum extrapolated to a solar phase angle of zero is 10.75 while the linear phase coefficient is 0.026mag deg^?1. The mean colors at solar phase angles greater than 30° are B?V = 0.92 and U?B = 0.52mag. No significant color variations over the surface were detected.  相似文献   

Rotational properties of asteroids: Correlations and selection effects     

E.F. Tedesco  V. Zappalá 《Icarus》1980,43(1):33-50

Rotational data on 321 asteroids observed as of late 1978 are analyzed. Selection effects within the sample are discussed and used to define a data set consisting of 134 main-belt, nonfamily asteroids having reliably determined periods and amplitudes based on photoelectric observations. In contrast to A. W. Harris and J. A. Burns (1979, Icarus40, 115–144) we found no significant correlation between rotational properties and compositional type. Smaller asteroids have a greater range of rotational amplitudes than the largest asteroids but are not, on the average, appreciably more elongated. While no definite relationship between asteroid size and rotation rate was found the distribution is not random. The largest asteroids have rotation periods near 7 hr compared with 10 hr for the smaller. A group of large, rapidly rotating, high-amplitude asteroids is recognized. A pronounced change in rotational properties occurs near this size range (diam = 200 ± 50 km) which also corresponds to the size at which a change of slope occurs in the size frequency distribution. We believe this size range represents a transition region between very large, rapidly rotating, low-amplitude (primordial?) objects and smaller ones having a considerably greater range of periods and amplitudes. Asteroids in this transition size range display an increase in rotational amplitude with increasing spin rate; other than this, however, there is no correlation between period and amplitude. The region of low spatial density in the asteroid belt centered near 2.9 AU and isolated from the inner and outer belt by the 2:5 and 3:7 commensurabilities is shown to be a region in which non-C or -S asteroids are overrepresented and which have marginally higher rotational amplitudes than those located in more dense regions. We attribute disagreements between our results and other studies of this type to the inclusion of non-main-belt asteroids and photographic data in the earlier analyses.  相似文献   

3D geoelectric tomography and archaeological applications1     

Paolo Mauriello  Dario Monna  Domenico Patella 《Geophysical Prospecting》1998,46(5):543-570

Following a previous paper in which the principles of a 3D ground-surface tomographic processing of self-potential data were established, we extend the method to active source geoelectric surveying. The main purpose of the new tomographic approach is to obtain a physical image reconstruction of the induced electric charges distributed over buried resistivity discontinuities. The information is produced in a probabilistic sense, as the mathematical formulation underlying the method treats only the intrinsic physical nature of the generated electric field underground and the method of its ground-surface detection, independently of the geometry of the unknown structures. In practice, a 3D tomography is realized by cross-correlating a set of distributed electric-field ground-surface data with a scanning function, representing a unit positive point charge located anywhere in the lower half-space. The resolution of the method is tested on the synthetic response of a 3D structural simulation of an archaeological target, consisting of an infinitely resistive prismatic body immersed in a half-space, including surface inhomogeneities and layering. Finally, the field response of a 3D structure consisting of a hypogeal dromos-chamber tomb inside the Sabine Necropolis at Colle del Forno, close to Rome, is presented and discussed.  相似文献   

ISO-LWS Observations of the NGC7129 Star Forming Region     

Elisabetta Tommasi  Dario Lorenzetti  Teresa Giannini  Brunella Nisini  Francesco Palla 《Astrophysics and Space Science》1998,261(1-4):187-190

We present far-infrared observations of the surroundings of the Herbig Be star LkHα234 in NGC7129, obtained with the Long Wavelength Spectrometer on board of the Infrared Space Observatory. [CII]158μm, [OI]63μm and [OI]146μm lines are detected everywhere in the mapped region and their intensity ratios are consistent with the model predictions of a photodissociation region. The spatial distribution of the emission features indicates the presence of a peak which does not coincide with the position of LkHα234, but is more likely associated with another nearby Herbig star, namely BD+65°1637; the far-ultraviolet field intensity and the density derived from our observations are fully consistent with this hypothesis. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

The Tucson revised index of asteroid data     

D. Bender  E. Bowell  C. Chapman  M. Gaffey  T. Gehrels  B. Zellner  D. Morrison  E. Tedesco 《Icarus》1978,33(3):630-631

Attention is called to the availability of the TRIAD computer file, a compilation of all reliable physical parameters for minor planets.  相似文献   

Antioxidant efficiency and detoxification enzymes in spotted dogfish Scyliorhinus canicula     

Stefania Gorbi  David Pellegrini  Sara Tedesco  Francesco Regoli   《Marine environmental research》2004,58(2-5):293

Although elasmobranchs are widely distributed species, commonly found on sandy, gravely or muddy bottoms, several biological aspects of their metabolism still remain poorly investigated. In this work the efficiency of antioxidant system and detoxification enzymes were investigated in the coastal spotted dogfish Scyliorhinus canicula and in the red mullet Mullus barbatus for comparison with a teleost species.Organisms were sampled during a bottom trawl survey and analyzed for the biotransformation activity (EROD), levels of metallothioneins, catalase, glutathione S-transferases and total oxyradical scavenging capacity (TOSC) toward peroxyl radicals and hydroxyl radicals.EROD activity in the elasmobranchs was more than one order of magnitude lower than in the red mullets, while similar levels of metallothioneins were measured in these species. S. canicula showed significantly lower antioxidant enzymes and a more reduced efficiency in neutralizing ^√OH; on the other hand the scavenging capability toward ROO^√ was comparable in S. canicula and M. barbatus.  相似文献   

The impact of Late Quaternary glacio‐eustasy and tectonics on sequence development: evidence from both uplifting and subsiding settings in Italy     

Massimo Zecchin  Mauro Caffau  Luigi Tosi  Dario Civile  Giuliano Brancolini  Federica Rizzetto  Cesare Roda 《地学学报》2010,22(5):324-329

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