Relativistic hierarchical cosmology     

Wiesław Betkowski 《Astrophysics and Space Science》1980,70(1):243-245

In this paper we discuss a hierarchical model of Universe which was proposed by Wesson (1975). We assert that the mathematical formalism used by Wesson leads to contradiction with Einstein's equations.  相似文献   

Discovery of powerful millisecond flares from Cygnus X-1     

Marek Gierli&#;ski  Andrzej A. Zdziarski 《Monthly notices of the Royal Astronomical Society》2003,343(3):L84-L88

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Dynamic ray tracing on Lagrangian manifolds     

Andrzej Hanyga 《Geophysical Journal International》1984,79(1):51-63

Summary. We show that Maslov's extension of the WKBJ method allows an extension of the dynamic ray tracing to wavefields involving caustics of arbitrary form. If the receiver lies off the caustics, then the synthetic seismogram can be obtained by integrating the DRT system along a single ray joining the receiver to the source which may touch caustics. If the receiver-lies in the vicinity of a caustic then DRT has to be carried out along a bunch of rays covering a neighbourhood of the receiver. Our approach encompasses pre-stressed and/or anisotropic media. Initial boundary conditions for a point source embedded in an anisotropic elastic medium are also presented.  相似文献   

Laboratory studies for beam plasma discharge experiments with rockets     

S.B. Lyakhov  A.D. Maiorov  G.G. Managadze  O.A. Povalyaev  A.I. Chmil  L.Yu. Kochmarev  E.G. Shustin  M.F. Friedrich  W.K. Riedler  A.N. Laliashvili  A. Kiraga  Z. Kłoss  Z. Kravchic  N.A. Leonov 《Planetary and Space Science》1982,30(4):347-357

Laboratory results of beam plasma discharge (BPD) (dimensions several metres) in a homogeneous atmosphere and a jet of neutral gas are presented. The beam was obtained by an electron gun of the same type as used in rocket experiments.The BPD parameters glow intensity, electromagnetic field and its spectrum, electron density as well as the flux of scattered electrons were measured. In addition, photographs of the BPD were taken. The threshold of BPD ignition was determined as a function of gas pressure and beam parameters. The initial stage of BPD formation as well as various types of oscillatory processes in the discharge were studied. A possible process of BPD initiation is presented.  相似文献   

Abnormal features of Macoma balthica (Bivalvia) in the Baltic Sea: alerting symptoms of environmental adversity?     

Sokołowski A  Wołowicz M  Hummel H  Smolarz-Górska K  Fichet D  Radenac G  Thiriot-Quiévreux C  Namieśnik J 《Marine pollution bulletin》2004,49(1-2):17-22

Recent studies of the Baltic clam Macoma balthica (L.) from the southern Baltic (the Gulf of Gdansk) have revealed striking morphological, histological and cytogenetic features. Strong deformation of the shell, including elongation of the posterior end and the appearance of an easily visible flexure in this part, has been recorded. The population contribution of the deformed blunt shelled ("irregular") clams ranged from 0% to 65% and tended to increase with depth. The morphologically "irregular" clams had higher accumulated tissue concentrations of trace metals (As, Ag, Cd, Pb, Cu and Zn), indicating a different metal handling ability. Adverse conditions in deeper water regions of the Gulf (e.g. hypoxia, hydrogen sulphide, elevated bioavailability of contaminants) have been suggested as inducers of the phenotypical changes (morphological deformation) in part of the population and, in parallel, of the specific physiological adaptations that result in higher metal accumulation in the "irregular" clams. Cytogenetic and histological analyses showed the presence of tumours in gill cells and digestive system of the affected clams, the prevalence of disseminated neoplasia ranging from 0% to 94% depending on the site. The disease was manifested by a modified karyotype (i.e. an abnormal number and morphology of chromosomes), a higher activity of nucleolar organizer regions (AgNORs), and tissue lesions (enlarged cells, actively proliferative with pleomorphic nuclei). Bottom sediments showed acute toxicity and have been proposed as a source of an initialising carcinogenic factor. However, none of the ecotoxicological studies provided was successful in the clear demonstration of a single (or multifactorial) agent that can account for the disseminated neoplasia.  相似文献   

The eastern continuation of the Cadomian orogen: U–Pb zircon evidence from Saxo-Thuringian granitoids in south-western Poland and the northern Czech Republic     

Żelaźniewicz  Andrzej  Dörr  Wolfgang  Bylina  Paweł  Franke  Wolfgang  Haack  Udo  Heinisch  Helmut  Schastok  Janina  Grandmontagne  Klaus  Kulicki  Cyprian 《International Journal of Earth Sciences》2004,93(5):773-781

We report U–Pb single zircon ages from three pre-Variscan granitoids in the NE part of the Bohemian Massif. The Platerówka granodiorite from the Lausitz-Izera Unit, the Polish Sudetes, has been dated at 533±9 Ma. The Bitouchov granite form the SW part of the South Krkonoe Unit, the Czech Sudetes, gave an age of 540+11/–10 Ma, and the Wdroe granodiorite in the Fore-Sudetic Block yielded 548±9 Ma. All these latest Vendian/Early Cambrian granitoids represent the post-tectonic expression of a late Proterozoic Cadomian orogenic cycle and demonstrate the eastward extent of the Cadomian basement into the Variscan orogen. Granodiorites of similar age have so far been reported from Brittany and especially from the Saxo-Thuringian Terrane to the NE and SW of the Elbe Fault Zone. We conclude that the Saxo-Thuringian Terrane extends across the Elbe and Sudetic Marginal Fault Zones into the Fore-Sudetic Block.  相似文献   

A comparison of MODIS-derived cloud amount with visual surface observations   总被引：6，自引：0，他引：6  

Andrzej Z. Kotarba   《Atmospheric Research》2009,92(4):522-530

Two main sources for global cloud climatologies are visual surface observations and observations made by spaceborne sensors. Satellite observations compared with surface data show in most cases differences ranging from − 15% up to − 1%, depending on sensor and observation conditions. These differences are partially controlled by sensors' cloud detection capabilities — a higher number of spectral bands and higher spatial resolution are believed to allow discrimination of clouds from land/ocean/snow background. A Moderate-Resolution Imaging Spectroradiometer (MODIS) produces images of the atmosphere in 36 spectral bands with a spatial resolution of 250–1000 m, thus having a capacity for cloud detection far more advanced than other operating sensors. In this study, instantaneous MODIS cloud observations were compared with surface data for Poland for January (winter) and July (summer) 2004. It was found that MODIS observed 4.38% greater cloud amount in summer conditions and 7.28% in winter conditions. Differences were greater at night (7–8%) than in daytime (0.5–7%) and correlations ranged between 0.577 (winter night) and 0.843 (winter day, summer day and night).  相似文献   

CO 2 emission trading model with trading prices     

Jarosław Stańczak  Paweł Bartoszczuk 《Climatic change》2010,103(1-2):291-301

In this paper we consider the buying/selling prices of carbon dioxide (CO₂) emission permits in trading models with uncertainty. Permission prices, although usually omitted from standard models, may significantly influence the trading market. We thus undertook to construct a more realistic trade model and to compare it with the standard one. To do this, we introduced several important changes to the standard model, namely, (1) a new optimized quality function; and (2) transactions with price negotiations between regions. We also enhanced the model using methods described in the literature to allow it to deal with reported emissions uncertainty. Additionally, we used an original method of simulating this kind of market based on a specialized evolutionary algorithm (EA).  相似文献   

Binary gas sorption/desorption experiments on a bituminous coal: Simultaneous measurements on sorption kinetics,volumetric strain and acoustic emission     

Zofia Majewska  Grażyna Ceglarska-Stefańska  Stanisław Majewski  Jerzy Ziętek 《International Journal of Coal Geology》2009,77(1-2):90-102

There is still no clear understanding of the specific interactions between coal and gas molecules. In this context sorption–desorption studies of methane and carbon dioxide, both in a single gas environment and gas mixtures, are of fundamental interest. This paper presents the results of unique simultaneous measurements of sorption kinetics, volumetric strain and acoustic emission (AE) on three tetragonal coal samples subjected to sorption of carbon dioxide and methane mixtures. The coal was a high volatile bituminous C coal taken from the Budryk mine in the Upper Silesia Basin, Poland. Three different gas mixtures were used in the sorption tests, with dominant CO₂, with dominant CH₄ and a 50/50 mixture.The experimental set-up was designed specially for this study. It consisted of three individual units working together: (i) a unit for gas sorption experiments using a volumetric method, (ii) an AE apparatus for detecting, recording and analysing AE, and (iii) a strain meter for measuring strains induced in the coal sample by gas sorption/desorption. All measurements were computer aided.The experiments indicated that the coal tested showed preferential sorption of CH₄ at 2.6 MPa pressure and exhibited comparable affinities for CH₄ and CO₂ at higher pressures (4.0 MPa). The results of chromatographic analysis of the gas released on desorption suggested that the desorption of methane from the coal was favoured. The relationship between the volumetric strain and the amount of sorbed gas was found to be non-linear. These results were contrary to common opinions on the coal behaviour. Furthermore, it appeared that the swelling/shrinkage of coal was clearly influenced by the network of fractures. Besides, the AE and strain characteristics suggested common sources of sorption induced AE and strain.The present results may have implications for the sequestration of carbon dioxide in coal seams and enhanced coalbed methane recovery (ECBM).  相似文献   

Meteoroid Stream Searching: The Use of the Vectorial Elements     

Tadeusz J. Jopek  Regina Rudawska  Przemysław Bartczak 《Earth, Moon, and Planets》2008,102(1-4):73-78

In this initial study, we propose a new distance function D _V involving heliocentric vectorial orbital elements. The function measures differences between: the orbital energies, the angular momentums vectors and the Laplace vectors. In comparison with the widely used D _SH criterion of Southworth and Hawkins, D _D criterion of Drummond and their hybrid D _H by Jopek, the new function contains one invariant with respect to the principal secular perturbation: the orbital energy. The new function proved to be useful in the classification amongst the IAU2003 meteoroids which we searched for streams by D _V function and also using D _SH and D _N -function given by Valsecchi et al. For major streams, the results agree very well. For minor, and near-ecliptical streams the results sometimes differ markedly.  相似文献