On the lunar semidiurnal variation of theD andF2 layers     

M. Bossolasco  A. Elena 《Pure and Applied Geophysics》1960,46(1):167-172

Summary The lunar semidiurnal variation of ionospheric absorption at Freiburg and of thef ₀ F2 at, Genova, Freiburg and Léopoldville has been deduced. The results are compared with those obtained by other Authors. Magnetic dip, rather than geomagnetic latitude, is found to be a parameter controlling the morphology of the lunar semidiurnal variation of theF2 layer. Finally, a graphical representation of the amplitude of lunar semidiurnal variation off ₀ F2 as function of the magnetic dip is also given.

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Riassunto Viene determinata la variazione lunare semidiurna dell'assorbimento ionosferico per Friburgo e della frequenza critica dello stratoF2 per Genova, Friburgo, Léopoldville. I risultati sono confrontati con quelli ottenuti da altri Autori per varie stazioni situate in diverse parti del globo. In particolare si trova che la inclinazione magnetica, meglio della latitudine geomagnetica, è il parametro che regola la morfologia della variazione lunare inF2. Infine si dà una rappresentazione grafica dell'ampiezza della variazione lunare dellaf ₀ F2 come funzione dell'inclinazione magnetica.

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This research was supported by a grant from the Committee on Lunar Variation (IAGA). The paper has been presented at the XII-Assembly of the I.G.G.U. in Helsinki (July–August 1960).  相似文献   

Multi-Element Reference Samples of Black Shale     

Lev L. Petrov  Yuri N. Kornakov  Irina la. Korotaeva  Elena A. Anchutina  Luidmila A. Persikova  Vera E. Susloparova  Irina N. Fedorova  Viktor A. Shibanov 《Geostandards and Geoanalytical Research》2004,28(1):89-102

This paper describes the creation of two new reference samples of black shale, SCHS-1 and SLg-1, collected in the Bodaibo Region of Irkutsk District (Siberia, Russia). These samples have been developed as State Standard Samples to meet the requirements of Russia's Normative Documents, so that they can be recognised by the Russian State Certification Agency and included on the State Register of certified reference materials. SCHS-1 was produced from shale of the Khomolkho suite; SLg-1 represents the average composition of the Sukhoy Log gold deposit (within Au mineralisation). The homogeneity was assessed by applying the concept of potential inhomogeneity, and the inhomogeneity uncertainties (σ_inhom) for the indicator elements that were estimated experimentally by silicate XRF analysis. It was found that a majority of the indicator elements was characterised by σ_inhom/Δ_p < 1/8 (Δ_p is the permissible certification uncertainty), and so σ_inhom was neglected for the indicator elements and all other elements that were included in their respective group. The value of σ_inhom calculated for Fe (σ_inhom,Fe/Δ_p > 1 /8) was taken into consideration for the noble metals and their associated elements (e.g., Ag, As, Au, etc.). More than fifty laboratories (thirty-seven from Russia) were involved in the interlaboratory experiment (ILE) to analyse these reference samples. The data obtained from the ILE allowed SCHS-1 and SLg-1 to be certified for, fifty-one and forty-three elements, respectively, as State Standard Samples.  相似文献   

Spectrophotometric Analysis of HII Regions in NGC 4258     

Marcelo Castellanos  Ángeles I. Díaz  Elena Terlevich  María Luisa García-Vargas 《Astrophysics and Space Science》1998,263(1-4):135-138

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Star Formation in Circumnuclear Rings     

Ángeles I. Díaz  Mar Álvarez-Álvarez  Miguel Sánchez Portal  Elena Terlevich  Itziar Aretxaga  Roberto Terlevich 《Astrophysics and Space Science》1998,263(1-4):139-142

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Kinematics and Stellar Populations of Seyfert Galaxies     

Luis Jiménez-Benito  Angeles Díaz  Roberto Terlevich  Elena Terlevich 《Astrophysics and Space Science》1998,263(1-4):111-114

We have analyzed high signal-to-noise spectra of 10 active galaxies in order to investigate the stellar populations of these objects and the kinematics of the gas and stars in their nuclei. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Evidence for the Blake event in volcanic rocks from Lipari (Aeolian Archipelago)     

Elena Zanella  & Marinella A. Laurenzi 《Geophysical Journal International》1998,132(1):149-158

Palaeomagnetic and geochronological measurements have been carried out on the late Pleistocene basaltic–andesitic unit of Monte Chirica–Costa Rasa, on the island of Lipari (Aeolian Archipelago). The lava flow sequence is about 10  m thick and has been sampled in detail. Magnetic properties are rather uniform; Curie temperatures of 540° to 580 °C, and the saturation IRM reached at applied values of 0.1  T point to titanomagnetite as the main magnetization carrier. Thermal and AF demagnetization have shown the presence of secondary magnetization components. These were removed mostly at 450°–500 °C or 20–30  mT, indicating a highly stable ChRM with directions from transitional to reverse. Where a ChRM could not be isolated by application of the demagnetization techniques, the converging remagnetization circles method gave a mean ChRM value fully comparable with that obtained from other methods. ⁴⁰Ar/³⁹Ar determinations were performed on two lava flows, in the lower and upper parts of the sequence. The former shows a transitional ChRM direction and a whole-rock age of 157±12  ka, the latter a reverse direction, a whole-rock age of 143±17  ka and a ground-mass age of 128±23  ka. The radiometric data and the reconstructed stratigraphy, which indicate ages of 150±10  ka and 104±3.5  ka, respectively, for the volcanic units at the bottom and top of the Monte Chirica–Costa Rasa unit, suggest that the reverse directions recorded in Lipari are related to the Blake event.  相似文献   

Stellar atmospheric parameters and the IR Caii triplet     

Elena Terlevich  Angeles I. Díaz  Roberto Terlevich 《Astrophysics and Space Science》1989,157(1-2):15-21

The IR Caii triplet at 8498, 8542, 8662 Å, relatively easy to observe and measure and free from atmospheric absorption bands, is a powerful tool for the study of the stellar populations in galaxies, provided that we can understand its behaviour with the stellar parameters: effective temperature, surface gravity and metal content. We present here the results of CCD spectroscopic observations for a sample of 86 stars covering a wide range in luminosity, effective temperature and metallicity (from subdwarfs to supergiants and –2.70[F3/H]0.43), in order to establish the dependence of the IR Caii triplet on stellar atmosphere parameters. We do not confirm previous results giving the main dependence on surface gravity. We find instead a bi-parametric dependence on metallicity and surface gravity, and no dependence on effective temperature.  相似文献   

The accumulation of Cu, Zn, Cd, and Pb in the aquatic biomass of sulphide tailing ponds     

Elena I. Khozhina  Barbara L. Sherriff 《Geochemistry International》2008,46(9):897-911

Flooding mine tailings to limit the oxidation of sulfides provides a habitat for aquatic organisms, such as plants, plankton, insects, and fish, which can uptake metals and, thus, threats for local ecosystems and influence the cycling of elements in biogeocenosis. An aquatic ecosystem developed naturally in sulphide tailing ponds containing cyanidation wastes of the Salair ore-refining plant (SORP), Russia, was studied. The objectives of this research were to: (i) reveal the level of contamination of living organisms in the tailing ponds compared to a natural control site and (ii) calculate the weight of metals in aquatic biomass to estimate the amount of metals transferring from the tailing ponds into the biogechemical cycle. The concentration of Cu, Zn, Cd, and Pb in the sediments of the tailing ponds is significantly higher than from the control site. Concentrations of Cu, Zn, Cd, and Pb in plant shoots were significantly higher than in the control and accumulated mainly in cell envelopes and membranes. The concentration of Pb in fish liver and eggs were 41 and 7.5 times higher, respectively, than maximum allowable concentrations. The biomass distribution between producers and consumers of the tailing pond ecosystem is similar to those of natural pond ecosystems. However, the weights of Cu, Zn, Cd, and Pb in all trophic levels per hectare of the tailing pond are orders of magnitude higher than those for Lake Baikal. The largest portion of metal circulates within the ecosystem of the Dyukov Ravine Pond with a maximum of 5 to 13% of this amount transferred into the surrounding environment through the food chains.  相似文献   

Submerged archaeological sites along the Ionian coast of southeastern Sicily (Italy) and implications for the Holocene relative sea-level change     

Giovanni Scicchitano  Fabrizio Antonioli  Elena Flavia Castagnino Berlinghieri  Andrea Dutton  Carmelo Monaco   《Quaternary Research》2008,70(1):26-39

Precise measurements of submerged archaeological markers in the Siracusa coast (Southeastern Sicily, Italy) provide new data on relative sea-level change during the late Holocene. Four submerged archaeological sites have been studied and investigated through direct observations. Two of them are Greek archaic in age (2.5–2.7 ka) and are now 0.98–1.48 m below sea level; the other two developed during the Bronze age (3.2–3.8 ka) and are now 1.03–1.97 m below sea level. These archaeological data have been integrated with information derived from a submerged speleothem collected in a cave located along the Siracusa coast at − 20 m depth. The positions of the archaeological markers have been measured with respect to present sea level, corrected for tide and pressure at the time of surveys. These data were compared with predicted sea-level rise curves for the Holocene using a glacio-hydro-isostatic model. The comparison with the curve for the southeastern Sicily coast yields a tectonic component of relative sea-level change related to regional uplift. Uplift rates between 0.3 and 0.8 mm/yr have been estimated.  相似文献   

Holocene environment and subsistence patterns near the Tree Shelter, Red Sea Mountains, Egypt     

Elena Marinova  Veerle Linseele  Pierre Vermeersch 《Quaternary Research》2008,70(3):392-397

The Tree Shelter site dates to the Early to Mid-Holocene (8000 to 4900 ¹⁴C yr BP). Present conditions around the site are hyperarid, but charcoal remains indicate less severe aridity at the time of its occupation. The environment around the site then supported a rich wadi vegetation, which allowed hunting during the Epipaleolithic and herding during the Neolithic occupation. Although more favorable than today, the environmental conditions also displayed a desert character and seem to have limited the range of domestic herbivores introduced in the area.  相似文献