Analysis of the V light curve of the system CW Cas     

R. Burchi  L. Milano  G. Russo 《Astrophysics and Space Science》1977,47(1):35-47

The V light curve of CW Cas, observed during 1972, has been analysed by different methods of solution. The results show great differences between rectifiable and direct methods.  相似文献   

A detailed study of Cepheid photometric properties in the Walraven system     

M. Coppola  G. Russo  C. Sollazzo 《Astrophysics and Space Science》1982,86(1):157-168

We have used the extensive set of photometric data in the VBLUW system (Pel, 1976) to perform a thorough statistical analysis of the physical properties of Cepheid variables, which can be inferred directly from these data. We have dealt with the problem of determining colour excesses and mean colours and temperatures; theoretical masses, radii and luminosities have been recalculated.  相似文献   

Relationships between ultrapotassic and carbonate-rich volcanic rocks in central Italy: petrogenetic and geodynamic implications     

Angelo Peccerillo 《Lithos》1998,43(4):267-279

The Pleistocene intra-Apennine volcanic (IAV) centres occurring east of the potassium-rich Roman comagmatic province show variable petrological and geochemical composition. Some rocks have a strongly undersaturated ultrapotassic kamafugitic affinity with K₂O/Na₂O=8–20, whereas the rocks from the southern center of Mt. Vulture are still strongly undersaturated in silica but are enriched in both Na₂O and K₂O with K/Na around unity. Carbonate-rich pyroclastic rocks, believed to represent carbonatitic magmas, are found in the IAV centers. Kamafugites have high abundances of LILE and high LILE/HFSE ratios, and their incompatible element patterns resemble closely those of ultrapotassic rocks from the adjoining Roman province. The Vulture volcanics also display high contents of LILE, but their LILE/HFSE ratios are intermediate between intraplate alkaline rocks and kamafugites. The carbonate-rich rocks exhibit an exotic mineralogy and high enrichments in LILE, which speaks for a carbonatitic affinity. However, they have similar incompatible element patterns but consistently lower abundances of almost all the elements than the associated silicate volcanics. These data favour the hypothesis that the IAV carbonate rocks may represent mixtures of silicate magmas and geochemically depleted carbonate material. The sedimentary carbonates that crop out extensively along the Apennine chain may be the source of barren carbonate material. Overall, geochemical data of IAV centres and of the rocks from the Roman province display strong geochemical and isotopic evidence of being generated in an upper mantle that was modified by addition of upper crustal material brought down by subduction processes. A possible exception is represented by Mt. Vulture which, however, occurs east of the main axis of the Apennines, on the western margin of the foreland Adria plate. The occurrence of strongly undersaturated alkaline rocks requires magma generation at high pressures and . This is in agreement with the hypothesis that subduction processes under the Apennines occurred by consumption of poorly hydrated thinned or delaminated continental crust.  相似文献   

On exceptionally mild winters in Genoa,Italy     

I. Dagnino  G. Flocchini  G. Russo 《Theoretical and Applied Climatology》1992,45(2):91-95

Summary Averages of air temperature, atmospheric pressure and rainfall measured at Genoa University Observatory for the winter (December to February) and December–March periods in the years 1987–88, 1988–89 and 1989–90 are examined. The average air temperature and the atmospheric pressure in these years were anomalously high while the rainfall was lower in 1988–89 and 1989–90. The results of an investigation performed to determine whether similar mild events occurred in the past are explained. Finally the possibility of more recent meteorological events being the result of an enhanced greenhouse effect is discussed.With 2 Figures  相似文献   

On the shape and orientation of the tail of Comet Kohoutek (1973f)     

Angelo Bernasconi  Giuseppe Forti  Luigi Pansecchi 《Icarus》1977,31(3):401-411

Twenty-two photographs of Comet Kohoutek (1973f) have been projected onto the comet's orbital plane under the assumption of a flat tail confined in that plane. The comet has a mixed-type tail; therefore the results concerning Type I and Type II components of the tail are presented separately. The axis of the Type I tail appears to sweep back and forth with respect to the prolonged radius vector in a rather periodical way. Interpretations advanced by some authors for the analogous case of Comet Burnham (1959k) are mentioned briefly. For the Type II tail, a comparison with a theoretical tail model by Sekanina has allowed us to establish when the onset of appreciable dust production occurred. Finally, mention is made of the fact that some peculiarities of the dust tail might be also explained by assuming a three-dimensional model.  相似文献   

Fe<Superscript>3+</Superscript> reduction during biotite melting in graphitic metapelites: another origin of CO<Subscript>2</Subscript> in granulites     

Bernardo?CesareEmail author  Sandro?Meli  Luca?Nodari  Umberto?Russo 《Contributions to Mineralogy and Petrology》2005,149(2):129-140

The Fe³⁺/Fe_tot of all Fe-bearing minerals has been analysed by Mössbauer spectroscopy in a suite of biotite-rich to biotite-free graphitic metapelite xenoliths, proxies of an amphibolite-granulite transition through progressive biotite melting. Biotite contains 9 to 16% Fe³⁺/Fe_tot, whereas garnet, cordierite and ilmenite are virtually Fe³⁺ -free (0–1% Fe³⁺/Fe_tot) in all samples, regardless of biotite presence. Under relatively reducing conditions (graphite-bearing assemblages), biotite is the only carrier of Fe³⁺ during high-temperature metamorphism; therefore, its disappearance by melting represents an important event of iron reduction during granulite formation, because haplogranitic melts usually incorporate small amounts of ferric iron. Iron reduction is accompanied by the oxidation of carbon and the production of CO₂, according to the redox reaction: Depending on the nature of the peritectic Fe-Mg mineral produced (garnet, cordierite, orthopyroxene), the CO₂ can either be present as a free fluid component, or be completely stored within melt and cordierite. The oxidation of graphite by iron reduction can account for the in situ generation of CO₂, implying a consequential rather than causal role of CO₂ in some granulites and migmatites. This genetic model is relevant to graphitic rocks more generally and may explain why CO₂ is present in some granulites although it is not required for their formation.  相似文献   

Nature, distribution and origin of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Olbia harbor (Northern Sardinia, Italy)   总被引：1，自引：0，他引：1  

De Luca G  Furesi A  Micera G  Panzanelli A  Piu PC  Pilo MI  Spano N  Sanna G 《Marine pollution bulletin》2005,50(11):1223-1232

The nature, origin and distribution of US EPA polycyclic aromatic hydrocarbons (PAHs) in the sediments of Olbia harbor (North Sardinia, Italy) were investigated by gas-chromatography/mass spectrometry (GCMS). PAH concentrations in the sediments (SigmaPAHs) ranged from 0.16 to 0.77 microg g(-1), indicating a homogeneously low level of pollution. A rather exceptional prevalence of low molecular weight PAHs was substantiated: nearly 80% of SigmaPAHs include naphthalene (15.19%) and phenanthrene (64.47%). Carcinogenic compounds were present in very low (BaP, BkF, BaA and DBA) or negligible (BbF and Inp) concentrations. As indicated by the Phen/Ant molar ratio, the main source of PAHs is petrogenic, probably due to oil spills from shipping. The low/high molecular weight ratio (ranging between 1.2 and 26) distinguishes the sediments of the tourist harbor from those of the commercial/industrial harbor. Moreover, a slight but meaningful pyrolytic contribution to pollution was found in the tourist harbor, which has the most polluted sediments in the whole harbor. Finally, good linear correlations were found between a selected PAH (Phen and Naph) and selected sums of PAHs (i.e. the total amount of the other 15 US EPA and the sum of low molecular weight PAHs).  相似文献   

A classification of particle motions in the equatorial plane of a gravitational monopole-quadrupole field in Newtonian mechanics and general relativity     

Angelo Armenti Jr. 《Celestial Mechanics and Dynamical Astronomy》1972,6(4):383-415

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Hydrostatic data for cargo ships obtained with regression analysis     

P. Cassella  G. Russo Krauss 《Ocean Engineering》1983,10(3):145-155

Starting from the regression analysis, equations are provided to determine the hydrostatic data for single-screw ships, fixing the block coefficient C_B and the principal dimensions L₀, B₀and T₀, with values T = (0÷1.5)T₀. This paper continues and develops a former one, in which the hydrostatic data were obtained in nondimensional form by means of graphs for tive parent hulls of the “Series 60”, with volume ₀ = 10,000 m³ at designed draught T₀.Numerical examples show the usefulness of the equations, both with respect of the direct calculations starting from the half-breadth values, and with respect to other methods.  相似文献   

The occurrence and significance of Pleistocene and Upper Pliocene sapropels in the Tyrrhenian Sea     

Kay-Christian Emeis  Angelo Camerlenghi  Judith A. McKenzie  Domenico Rio  Rodolfo Sprovieri 《Marine Geology》1991,100(1-4):155-182

Numerous sapropels and sapropelic strata from Upper Pliocene and Pleistocene hemipelagic sediments of the Tyrrhenian Sea show that intermittent anoxia, possibly related to strongly increased biological productivity, was not restricted to the eastern Mediterranean basins and may be a basin-wide result of Late Pliocene-Pleistocene climatic variability. Even though the sapropel assemblage of the Tyrrhenian Sea clearly originates from multiple processes such as deposition under anoxic conditions or during spikes in surface water productivity and lateral transport of organic-rich suspensates, many “pelagic sapropels” have been recognized. Stratigraphic ages calculated for the organic-rich strata recovered during ODP Leg 107 indicate that the frequency of sapropel formation increased from the lowermost Pleistocene to the base of the Jaramillo magnetic event, coinciding with a period when stable isotope records of planktonic foraminifera indicate the onset of climatic cooling in the Mediterranean. A second, very pronounced peak in sapropel formation occurred in the Middle to Late Pleistocene (0.73-0.26 Ma). Formainifers studied in three high-resolution sample sets suggest that changes in surface-water temperature may have been responsible for establishing anoxic conditions, while salinity differences were not noted in the faunal assemblage. However, comparison of sapropel occurrence at Site 653 with the oxygen isotopic record of planktonic foraminifers established by Thunell et al. (Proc. ODP, Sci. Results 107, 1990) indicates that sapropel occurrences coincide with negative δ¹⁸O excursions in planktonic foraminifers in thirteen of eighteen sapropels recognized in Hole 653A. A variant of the meltwater hypothesis accepted for sapropel formation in the Late Pleistocene eastern Mediterranean may thus be the cause of several “anoxic events” in the Tyrrhenian as well. Model calculations indicate that the amount of oxygen advection from Western Mediterranean Deep Water exerts the dominant control on the oxygen content in deep water of the Tyrrhenian Sea. Inhibition of deep-water formation in the northern Adriatic and the Balearic Basin by increased meltwater discharge and changing storm patterns during climatic amelioration may thus be responsible for sapropel formation in the Tyrrhenian Sea.  相似文献