Showing papers by "University of Warsaw published in 1973"
730 citations
TL;DR: A new determination of the binding energy of light hypernuclei (A ⩽ 15) is reported in this paper, based on the analysis of some 27 000 π − mesonically-decaying hypernucus produced by stopping K − mesons in nuclear emulsion.
271 citations
TL;DR: A similar singularity has been shown to occur as a result of spherically symmetric gravitational collapse of a cloud of dust as discussed by the authors, and it was thought that the singularities might be a consequence of the high symmetry of the models.
Abstract: IT has long been recognized that isotropic models of the world are singular. The models, be they Newtonian or based on Einstein's equations of general relativity, lead to the prediction of at least one moment in the history of the Universe with an infinite density of matter. A similar singularity has been shown to occur as a result of spherically symmetric gravitational collapse of a cloud of dust1. For some time it was thought that the singularities might be a consequence of the high symmetry of the models.
247 citations
TL;DR: In this paper, a canonical formalism based on the geometrical approach to the calculus of variations is given, which enables to define whole the canonical structure (physical quantities, Poisson bracket, canonical fields) without use of functional derivatives.
Abstract: A canonical formalism based on the geometrical approach to the calculus of variations is given. The notion of multi-phase space is introduced which enables to define whole the canonical structure (physical quantities, Poisson bracket, canonical fields) without use of functional derivatives. All definitions are of pure geometrical (finite dimensional) character.
194 citations
TL;DR: In this article, the problem of a spatially flat and homogeneous gravitational field produced by spinning matter is considered within the framework of the Einstein-Cartan theory, and the effect of torsion is greater than that of shear, solutions of the field equations have no cosmological singularity.
109 citations
TL;DR: A monogenic mutant of Aspergillus nidulans simultaneously lacking cystathionine β-synthase (EC 4.2.1.13) and L-serine sulfhydrylase was isolated and the physiological role of the latter enzyme appears to be in cystATHionine synthesis rather than in cysteine synthesis from serine.
80 citations
TL;DR: In this paper, the Luttinger model was used to explain interband and intraband magnetoabsorption in pure HgTe thin crystals in the spectral region 300-400 meV.
Abstract: Magnetoabsorption associated with ${\ensuremath{\Gamma}}_{6}\ensuremath{\rightarrow}{\ensuremath{\Gamma}}_{8}$ transitions was investigated at 4.4 \ifmmode^\circ\else\textdegree\fi{}K, on pure $n$-type HgTe thin crystals in the spectral region 300-400 meV for $\ensuremath{\sigma}$ and $\ensuremath{\pi}$ polarizations. Analysis of experimental spectra is performed using both the three-band model (including the nonparabolicity), and the theory of Luttinger. Band parameters are determined by fitting transition energies: ${E}_{{\ensuremath{\Gamma}}_{8}}\ensuremath{-}{E}_{{\ensuremath{\Gamma}}_{6}}=302.5$ meV, $\frac{{m}_{{\ensuremath{\Gamma}}_{6}}}{{m}_{0}}=0.028\ifmmode\pm\else\textpm\fi{}0.001$, and ${g}_{{\ensuremath{\Gamma}}_{6}}=\ensuremath{-}41\ifmmode\pm\else\textpm\fi{}4$ at $\ensuremath{\Gamma}$. ${\ensuremath{\Gamma}}_{8}$ Luttinger parameters (${\ensuremath{\gamma}}_{1}=\ensuremath{-}12.8,\overline{\ensuremath{\gamma}}=\ensuremath{-}8.4,\ensuremath{\kappa}=\ensuremath{-}10.5$) satisfactorily explain interband and intraband ${\ensuremath{\Gamma}}_{8}$ magnetoabsorption. The structure of ${\ensuremath{\Gamma}}_{8}$ magnetic levels near $\ensuremath{\Gamma}$ is quantitatively described by calculating the ${k}_{H}$ dependence of the energies in the [111] direction. A complex structure is found for a set of heavy holes.
72 citations
53 citations
TL;DR: Histological studies of the brain of crickets following injection of reserpine show a large degree of accumulation of neurosecretion in the cells of the pars intercerebralis as compared with control insects.
53 citations
TL;DR: In this paper, the Raychaudhuri equation and other relations for a spinning fluid in the framework of the Einstein-Cartan theory are obtained and it is shown that non-singular cosmological models of the Bianchi types I÷VIII are possible.
52 citations
TL;DR: In this article, the γ spectra obtained with K− mesons stopped in 6Li and 7Li targets exhibited a γ line at 1.09 MeV (intensities 0.14 ± 0.02% and 0.37 ± 0.04%, respectively) which could be identified as a hypernuclear line, and a second one at (1.42 MeV), the assignment of which is less certain.
TL;DR: In this article, the energy dependence of π ± p interactions at 8 and 16 GeV/c was investigated in terms of integrated distributions as functions of x, reduced rapidity ζ and p ⊥ 2, and double differential cross sections.
TL;DR: In general, spontaneously ovulated eggs developed better after activation (both in quantitative and qualitative terms) than those obtained following hormonal treatment and in embryos developed from spontaneously ovulate eggs n /2 n mosaics were observed for the first time on the 5th day.
Abstract: Newly ovulated eggs from CBA-p and CBA-T6T6 inbred strains were activated in situ with an electric shock of 20–50 V. Both spontaneously ovulating females mated with vasectomized males (strain A) and those induced to ovulate and kept apart from males were used. The immediate reaction of eggs was examined 5–7 h after activation and their subsequent development was followed every day up to the 6th day (eggs examined on the 5th and 6th day were tube-locked by a ligature). In spontaneous ovulators the highest yield of activated eggs was obtained following 30 V shock (75%), with a mean for four series (20, 30, 40 and 50 V) of 46·1%. The most common reaction is extrusion of the second polar body (2 PB) and formation of one pronucleus (about 70% of activated eggs). Other types of reaction include: immediate cleavage, suppression of 2 PB with formation of two or, very rarely, one pronucleus. Thus the majority of eggs are potentially haploid. No relationship between the frequency of various types of reaction and the strength of the shock (voltage) was observed. Up to the 3rd day cleavage proceeds at a normal rate and appears to slow down during the 4th day. In spontaneously ovulating females the incidence of blastocysts among developing eggs rises from 3·4% on the 4th day to 52·5% on the 5th day; the corresponding figures for induced ovulations are 10% and 23·6%. Some embryos despite being composed of a large number of cells (40–120) do not undergo cavitation and remain morulae. On the basis of karyological examination of 60 embryos with analysable metaphase plates 60% were classified as haploid, 16·7% as diploid, 1·7% as tetraploid and 21·6% as haploid/diploid mosaics. During early cleavage binucleate blastomeres (a presumed step in regulation from n to 2 n ) were observed only in eggs from induced ovulations. In embryos developed from spontaneously ovulated eggs n /2 n mosaics were observed for the first time on the 5th day. In general, spontaneously ovulated eggs developed better after activation (both in quantitative and qualitative terms) than those obtained following hormonal treatment.
TL;DR: In this article, the second-order exchange energy predicted by the Murrell-Shaw and Musher-Amos (MS-MA) theory was evaluated analytically for the hydrogen molecule ion.
Abstract: The exchange polarization energy and higher-order exchange corrections arising in the second order of the Murrell-Shaw and Musher-Amos (MS-MA) theory are evaluated analytically for the hydrogen molecule ion. At large internuclear distances the second-order exchange energy predicted by MS-MA theory behaves like . It represents only 80% of the difference between the exact result of Holstein and the asymptotic value of the first-order exchange energy. The same result holds for the case of Hirschfelder-van der Avoird (HAV) and Hirschfelder-Silbey (HS) theories.
TL;DR: In this paper, the canonical formulation of the relativistic theory of perfect fluids is given, and the canonical formalism for charged particles interacting with electromagnetic field is briefly discussed, and several implications of conformal symmetry are discussed.
TL;DR: In this article, the effect of specific solvation of electrode and depolarizer by different constituents of mixed water-alcohol solvents on electrode kinetics was investigated for the case of the Mn 2+ /Mn/Hg system.
TL;DR: Re-investigation of the gibberellins in apple seed has established the presence of GA4 and GA7 and of traces of GA9 and the present results do not change the previous conclusions that during the stratification of apple seed the level of GA7 remains fairly constant while that ofGA4 increases.
Abstract: Re-investigation of the gibberellins in apple seed has established the presence of GA4 and GA7 and of traces of GA9. The fraction, previously considered to be GA7 by TLC, contains small amounts of GA4 and traces of GA9; and the fraction, characterized as GA4 by TLC, contains traces of GA7 and GA9. However the present results do not change the previous conclusions that during the stratification of apple seed the level of GA7 remains fairly constant while that of GA4 increases.
TL;DR: The question of gravitational collapse to a black hole is treated in the context of an expanding universe in this article, where the question is treated as a special case of the singularity problem in general.
Abstract: The question of gravitational collapse to a black hole is treated in the context of an expanding universe.
TL;DR: In this paper, the binding energy of the Λ-particle in the J = 1 2 and 3 2 states of Λ3H and the doublet and quartet Λd scattering lengths are calculated with a separable ΛN-ΣN potential matrix, fitted to experimental data in Λ N and ΣN channels.
TL;DR: In this paper, the formation of a relatively stable homogeneous supersaturated nickel amalgam for concentrations lower than 10−3 and 10−2 M, at temperatures 20° and 200°C respectively, was found.
TL;DR: In this paper, the cross sections for the (n, n') m and (n 2n) reactions on the target nuclei 113 In and 204 Pb were measured by the activation method in the neutron energy range 13 to 18 MeV.
TL;DR: In this article, a new formula for induced transition amplitudes in intense photon beams is derived which relates the photon-number description to the coherent field description according to this formula transition amplitude describing processes in which $m$ photons are added to the intense one-mode beam or subtracted from that beam are equal to the Fourier coefficients of the corresponding amplitude in the external field, expanded with respect to the phase of the classical field.
Abstract: A new formula for induced transition amplitudes in intense photon beams is derived which relates the photon-number description to the coherent-field description According to this formula transition amplitudes describing processes in which $m$ photons are added to the intense one-mode beam or subtracted from that beam are equal to the Fourier coefficients of the corresponding amplitude in the external field, expanded with respect to the phase of the classical field The same formula is used to study the expectation values of dynamical variables in $n$-photon states leading to the conclusion that for large $n$ such states are very much like classical statistical states with a given amplitude and evenly distributed phase
TL;DR: The most stable tautomeric forms have been determined and the electrostatic energy of the coplanar interaction of an adenine · thiouracil pair has been calculated.
TL;DR: In this paper, the polarographic reduction of 4-thiomethyluracil, 1-methyl-4-thiamethylURacil and 4-THI-uridine was investigated by d.c. polarography, cyclic voltammetry, preparative electrolysis, and coulometry.
Journal Article•
TL;DR: In this article, the results of investigations of the biostratigraphy of Polish Buntersandstein, on the base of megaspores, are presented, and a new stratigraphic and palaeo-geographic interpretation of Bunter, based on megaspore and lithological development, is given.
Abstract: The results of investigations of the biostratigraphy of Polish Buntersandstein, on the base of megaspores, are presented. Samples were taken from four borings, three in the North-East and one in Central Poland. 39 megaspore species belonging to 15 genera are described. Of these, 29 species and one genus are new. The aboundance and variability of megaspores in vertical profile enabled the author to distinguish three index megaspore assemblages (I, II, III). A new stratigraphic and palaeogeographic interpretation of Bunter, based on megaspores and lithological development, is given.
Journal Article•
Journal Article•
TL;DR: Simoceratids (Idocer atinae) represent a peculiar group of Upper Jurassic ammonites typical of the Tethyan province, where some ammonites closer to Kimmeridgian nebroditids than to co-occurring perisphinctids are found.
Abstract: Simoceratids (Idoceratinae) represent a peculiar group of Upper Jurassic ammonites typical of the Tethyan province. The earliest Idoceratinae, the genera Idoceras and Nebrodites , were thought to appear not before the uppermost Oxfordian. However, in Mid-Oxfordian strata of the Polish Jura Chain there occur some ammonites closer to Kimmeridgian nebroditids than to co-occurring perisphinctids. These forms, separated here as the subgenus Passendorferia nov. of the genus Nebrodites, most probably evolved from some Kranaosphinctes and lead to Nebrodites proper. The nominal genus of this subfamily, Idoceras Burckhardt, 1906, presumably represents a side-branch of nebroditids.
TL;DR: The synthesis of two enzymes of the arginine catabolic pathway, arginase and ornithine δ-transaminase, in Aspergillus nidulans was found to be sensitive to both glucose and ammonium repression.
Abstract: The synthesis of two enzymes of the arginine catabolic pathway, arginase and ornithine δ-transaminase (OTAse), in Aspergillus nidulans was found to be sensitive to both glucose and ammonium repression. The glucose and nitrogen starvation result in the identical derepression of OTAse synthesis and have no effects on arginase synthesis. Glucose and ammonium affect the kinetics of induction of both enzymes, however, the effect of ammonium is much stronger. Evidence was obtained for the direct involvement of ammonium in the repression phenomenon. The relations between glucose and ammonium repression are discussed.
TL;DR: In this paper, the multiplicity of charged particles and π 0 mesons in π − p and ε − n interactions was analyzed and compared to various models, and it was shown that the average multiplicity tends to increase with increasing number of particles.