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Showing papers by "University of Warsaw published in 1976"


Journal ArticleDOI
TL;DR: In this article, a nonlinear wave mechanics based on Schrodinger-type equation with nonlinearity −bψ ln | ψ |2 is constructed, and its most attractive features are: existence of the lower energy bound and validity of Planck's relation E = hω.

687 citations


Journal ArticleDOI
TL;DR: In this paper, the authors calculated the hydrogen-bond energy of two water molecules as a sum of the electrostatic, exchange, induction and dispersion contributions, neglecting the electron correlation within the free monomers.
Abstract: The hydrogen-bond energy of two water molecules has been calculated as a sum of the electrostatic, exchange, induction and dispersion contributions, neglecting the electron correlation within the free monomers. The last two contributions have been evaluated by applying a variation-perturbation procedure and making use of an extensive basis set of contracted gaussian functions. It has been shown that the sum of the electrostatic, exchange and induction energies is very close to the binding energy obtained within the SCF scheme. The dispersion contribution to the hydrogen-bond energy amounts to about 2 kcal/mole and causes substantial reduction of the equilibrium distance of the oxygen atoms. The minimum of the total energy is attained at 2·86 A and its depth is equal to 5·8 kcal/mole. These values are consistent with the experimental results.

261 citations



Journal ArticleDOI
TL;DR: In this article, the first-order interaction energy of many closed-shell molecules was derived assuming a determinantal form for the wave-functions of free molecules, assuming that the determinants describing the free molecules are constructed from the Hartree--Fock orbitals.
Abstract: Assuming a determinantal form for the wave-functions of free molecules, explicit formula for the first-order interaction energy of many closed-shell molecules was derived. Provided that the determinants describing the free molecules are constructed from the Hartree--Fock orbitals, the two-, three-, and four-body effects predicted by the first-order perturbation theory are closely related to those which one obtains in the framework of the Loewdin LCAO MO-type approach. The results are illustrated by numerical calculations for the system of three ground-state helium atoms. (auth)

146 citations


Journal ArticleDOI
TL;DR: In this article, a general scheme of constructing a canonical structure (i.e., Poisson bracket, canonical fields) in classical field theories is proposed, which is manifestly independent of the particular choice of an initial space-like surface in space-time.
Abstract: A general scheme of constructing a canonical structure (i.e. Poisson bracket, canonical fields) in classical field theories is proposed. The theory is manifestly independent of the particular choice of an initial space-like surface in space-time. The connection between dynamics and canonical structure is established. Applications to theories with a gauge and constraints are of special interest. Several physical examples are given.

140 citations


Journal ArticleDOI
15 Feb 1976
TL;DR: In this article, the ground state energy of HeH+ has been calculated in the Born-Oppenheimer approximation for 0.9 ⩽ R ⌽ 4.5 au by using an 83-term variational wave function in elliptic coordinates and including the interelectronic distance.
Abstract: The ground state energy of HeH+ has been calculated in the Born—Oppenheimer approximation for 0.9 ⩽ R ⩽ 4.5 au by using an 83-term variational wavefunction in elliptic coordinates and including the interelectronic distance. The resulting potential curve has been used to compute the quasibound state spectrum of the ion.

132 citations


Journal ArticleDOI
S. Kurcyusz1
TL;DR: In this article, the existence of Lagrange multipliers for general nonlinear programming problems is investigated and some regularity conditions are formulated which are, in a sense, the weakest conditions to assure the presence of multipliers.
Abstract: The paper deals with the existence of Lagrange multipliers for a general nonlinear programming problem. Some regularity conditions are formulated which are, in a sense, the weakest to assure the existence of multipliers. A number of related conditions are discussed. The connection between the choice of suitable function spaces and the existence of multipliers is analyzed.

112 citations


Journal ArticleDOI
TL;DR: In this paper, the intensity distribution of inelastically scattered thermal and hot neutrons on hydrogen impurities in α-palladium hydride has been studied as a function of concentration, temperature, momentum transfer and different annealing procedures.

96 citations


Journal ArticleDOI
TL;DR: It was shown that 9-substituted isogua nines, and isoguanosine, in aqueous medium are predominantly in the form N(1)H,2-keto-6-amino, and the enol form is favoured by a decreases in solvent polarity, by a decrease in concentration in dioxane, or an increase in temperature in chloroform solution.
Abstract: Ultraviolet and infrared absorption spectroscopy, in aqueous and non-aqueous media, have been employed to study the tautomerism of 9-substituted isoguanines, including the nucleoside isoguanosine. With the aid of a series of model compounds, it was shown that 9-substituted isoguanines, and isoguanosine, in aqueous medium are predominantly in the form N (1) H, 2-keto-6-amino. In dioxane solution the tautomeric equilibrium is shifted in the direction of the enol form. The shift towards this form is accentuated for those analogues in which the exocyclic amino group is methylated. With the aid of N6,N6, 9-trimethylisoguanine, and 9-octyl analogue, the tautomeric constant was studied as a function of concentration, temperature, and solvent polarity, and the results applied to evaluate the tautomeric equilibria of 9-methylisoguanine and isoguanosine as a function of these variables. In general the enol form is favoured by a decrease in solvent polarity, by a decrease in concentration in dioxane, or an increase in temperature in chloroform solution. Syntheses are described for several N6 amino and methylamino derivatives of 2-methoxy-9-methylpurine, and 3-methyl-5-oxo-7,8-dihydroimidazo (2,1-i) purine, which served as an analogue of the unavailable 1,9-dimethylisoguanine.

87 citations


Journal ArticleDOI
TL;DR: In this paper, a simple model of heavy-ion collisions is proposed, where classical equations of motion with inclusion of a phenomenological two-body friction force are integrated numerically along trajectories.

70 citations


Journal ArticleDOI
TL;DR: In this article, the potential energy curves for the hydrogen molecule in the c3Πu, I1Πg, and i3 Πg states have been calculated in the Born-Oppenheimer approximation.

Journal ArticleDOI
TL;DR: In this paper, the authors extend the quantum source field method to demonstrate the non-Markovian character of the quantum electrodynamic Bloch equations, via a natural perturbation technique, for the vacuum expectation value of the two-level atomic inversion operator.

Journal ArticleDOI
TL;DR: The present experiments corroborate earlier observations that parthenogenetic mouse embryos, even if diploid, rarely survive in the uterus beyond the egg-cylinder stage and explain the delayed preimplantation development and low implantation rate.
Abstract: Swiss albino and C57BL/10 eggs from induced ovulations, and spontaneously ovulated A eggs, were activated in vitro by a heat shock of 44 °C for 5 or 7·5 min and cultured in the presence of 10 μg/ml of Cytochalasin B (CB) for 5–8 h. The activation rate was about 70 % in Swiss albino, 40 % in C57BL and 90 % in A eggs. CB suppressed second polar body (2P.B.) formation in over 90 % of activated eggs, with the majority containing two pronuclei. When eggs were placed in CB-free medium their surface became wrinkled and they formed protrusions of various sizes, which in some eggs detached to form enucleate or pronucleate cytoplasmic fragments; some eggs broke down completely into fragments. In most eggs, however, the surface smoothed out in a few hours and suppression of 2P.B. appeared to be permanent. The rate of development of these eggs after transplantation to the oviduct was delayed in terms both of cell divisions and of the time of blastocyst formation. Out of 41 implants collected on the 8th–10th day of pregnancy only two healthy looking egg-cylinders were found on the 8th and 9th day; both were retarded, at the stage characteristic for the 7th day of normal development. The reasons for delayed preimplantation development and low implantation rate are discussed. The present experiments corroborate earlier observations that parthenogenetic mouse embryos, even if diploid, rarely survive in the uterus beyond the egg-cylinder stage.

Journal ArticleDOI
TL;DR: In this paper, the decay of the 232 U decay chain was investigated down to 212 Pb using Ge(Li) spectrometers in single and coincidence measurements in terms of the Hindrance Factor (HF) calculated for all α-transitions.

Journal ArticleDOI
TL;DR: In this paper, a new approximation method for determining resonance properties of atomic systems interacting with intense photon beams was developed, based on an improved iteration procedure, which leads to analytic expressions for the atomic density matrix from which positions of the resonances are determined.
Abstract: We develop a new approximation method for determining resonance properties of atomic systems interacting with intense photon beams. This method, based on an improved iteration procedure, leads to analytic expressions for the atomic density matrix from which positions of the resonances are determined. Our iteration procedure is more rapidly convergent than the continued-fraction method, and already in its second step reproduces the Bloch-Siegert shift of the one-photon resonance within 1 ppm.

Journal ArticleDOI
TL;DR: The termyoung embryo proper is proposed to denote the globular embryo which already possesses separate plerome and periblem mother- cells and mother-cells of the iec layer and of clumella.
Abstract: The development of the proembryo of rape Brassica napus L. from the zygote to the young embryo proper is described. A number of regularities were found in the direction, succession, and distribution of segmental and differentiating divisions of the proembryo. The direction of the divisions seems to foe determined by the direction of growth and the shape of the cells. The termyoung embryo proper is proposed to denote the globular embryo which already possesses separate plerome and periblem mother-cells and mother-cells of the iec layer and of clumella. The body of the embryo proper is derived from the apical cell ca which arose from the first division of the zygote and from the hypophysis - the only suspensor cell which closes the spheroid of the embryo. The development of the Brassica napus L. proembryo follows the sub-archetype Capsella bursa-pastoris in the IV megarchetype of Soueges.

Journal ArticleDOI
01 Sep 1976-Talanta
TL;DR: The diffusion-layer model for the chalcocite (Cu(2)S) membrane electrode is discussed and it is equivalent to a simpler model based on exchange reactions at the electrode surface.

Journal ArticleDOI
TL;DR: In this article, the authors analyzed π + p collisions at 8, 16 and 23 GeV/c and showed that the ϱ 0 cross section increases with energy, such that π 0 /π − ratio remains constant.

Journal ArticleDOI
TL;DR: In this paper, the concepts of condition number, numerical stability and well-behavior for solving systems of nonlinear equations were introduced, and necessary and sufficient conditions for numerical stability of a stationary are given.
Abstract: The concepts of the condition number, numerical stability and well-behavior for solving systems of nonlinear equationsF(x)=0 are introduced. Necessary and sufficient conditions for numerical stability and well-behavior of a stationary are given. We prove numerical stability and well-behavior of the Newton iteration for solving systems of equations and of some variants of secant iteration for solving a single equation under a natural assumption on the computed evaluation ofF. Furthermore we show that the Steffensen iteration is unstable and show how to modify it to have well-behavior and hence stability.

Journal ArticleDOI
TL;DR: In this paper, the authors found that female students liked and helped similar more than dissimilar partners and that liking for similar partners correlated positively with subject's self-esteem, but no such relationship existed in the case of a dissimilar partner or between liking and helping.
Abstract: 112 Female students both liked and helped similar more than dissimilar partners. Liking for similar partners correlated positively with subject's self-esteem, but no such relationship existed in the case of a dissimilar partner, or between liking and helping.

Journal ArticleDOI
TL;DR: Isoguanosine-5'-pyrosphosphate, in the presence of an oligonucleotide primer, was polymerized by Escherichia coli polynucleotide phosphorylase under conditions analogous to those required for polymerization of 5'-GMP, creating a multistranded helix with a stability considerably higher than that of poly(G), and fully resistant to various nucleolytic enzymes.
Abstract: Isoguanosine-5'-pyrosphosphate, in the presence of an oligonucleotide primer, was polymerized by Escherichia coli polynucleotide phosphorylase under conditions analogous to those required for polymerization of 5'-GMP. The resulting poly(isoguanylic acid), poly(isoG), was a multistranded helix with a stability considerably higher than that of poly(G), and fully resistant to various nucleolytic enzymes. The polymer exhibited a two-step temperature transition profile in moderately alkaline propylene glycol. Alkaline titration in aqueous medium, by ultraviolet and circular dichroism spectroscopy, showed two clearly defined transitions, the second of which was fully cooperative. The accompanying changes in sedimentation constants were consistent with a structure for poly(isoG) of a fourstranded helix, like neutral poly(G). In acid medium, spectral and potentiometric titrations demonstrated the existence of more than one transition in the pH range 6-12, with accompanying protonation of the isoguanosine residues. In neutral medium the polymer formed no complexes with other potentially complementary homopolymers. In acid medium, on the other hand, the protonated form of poly(isoG) did form a triple-stranded complex with poly(I), viz. 2poly(I) . poly(isoG)+. Possible structures are formulated for the neural and protonated forms of poly(isoG) which account for the two-step thermal transition in alkaline propylene glycol and on alkaline titration in aqueous medium. The nature of the protonated form, and its complex with poly(I) is also discussed.

Journal ArticleDOI
TL;DR: Cooling of larvae of G. mellonella in the final instar results in a serious disturbance in their later development, which concerns the transition to additional larval stages, loss of the ability to spin cocoons, and the formation of individuals incapable of continuing normal development.

Journal ArticleDOI
TL;DR: In this article, a set of linear equations is derived from which the values of the deformation parameters can be calculated from the Landau parameters of the spin dependent terms in the quasi-particle interaction in nuclear matter.

Journal ArticleDOI
TL;DR: In this article, a graphite-based thin mercury film electrode (TMFE) and a HMDE taken as a model electrode applying cyclic and stripping voltammetry was compared, and the experimental results obtained for amalgam forming metals were also compared with the rigorous voltammetric theory given by de Vries and van Dalen.

Journal ArticleDOI
TL;DR: In this article, the production of ρ0(770) and f(1270) in π−p interactions at 16 GeV/c was studied and it was found that the data can be interpreted in terms of two production processes: the central production of resonances and the fragmentation of the beam particle.


Journal ArticleDOI
TL;DR: Differential cross sections have been measured for the ground state transitions at a bombarding energy of 93 MeV; the cross section leading to the first excited state of 212 Po was also measured as mentioned in this paper.

Journal ArticleDOI
TL;DR: Golgi-rich fractions were prepared from onion stems and Calendula officinalis seedlings by the procedure described earlier and it has been shown that the enrichment of UDPG:sterol glucosyltransferase activity was 37–295-fold greater compared with the crude homogenates.

Journal Article
TL;DR: The results combined with those of previous studies on the ultrastructure of p,eridermal derivatives in graptolites reveal a substantial difference at the submicroscopic level between the fusellar component of the periderm in the pterobranchia and that of the Graptolithina.
Abstract: The ultrastructure of the organic coenecium in living Cephalodiscus (Cephalodiscus) inaequatus (Andersson) studied with the transmission electron mi­ croscope reveals a fabric and pattern very similar to that recognized in living Rhab­ dopleuTa compacta (Hincks) by Dilly (1971). The same techniques used to study the ultrastructure of Jurassic Rhabdopleura kozlowskii Kulicki and Ordovician Rhab­ dopleurites primaevus Kozlowski indicate that the nature of the fibrous unit ele­ ments of the periderm and their characteristic pattern remain unchanged within the Pterobranchia, at least since the Ordovician. The results combined with those of previous studies on the ultrastructure of p,eridermal derivatives in graptolites (Towe & Urbanek, 1972; Urbanek & Towe, 1974, 1975), reveal a substantial difference at the submicroscopic level between the fusellar component of the periderm in the pterobranchia and that of the Graptolithina. The presumed homology between fusellar tissues of both groups constitutes the main argument in Kozlowski's suggestion (1938, 1949, 1966a) of a close affinity between pterobranchs and graptolites. A reevaluation of his line of reasoning enables us to conclude that Kozlowski's main criterion of homology was the specificity of the structures involved. This requirement is not fulfilled at the ultrastructural level because of substantial differences in the nature of the unit elements and their pat­ tern. Moreover, other data on the ultrastructural anatomy of graptolites (very early deposition of cortical tissue over juvenile thecae; presence of cortical deposits over the inner surface of thecae; simultaneous secretion of successive fuselli and cor­ responding layers of cortical tissue) contradict the mode of secretion of the grap­ tolite skeleton as suggested in the classical Kozlowski hypothesis. In contrast to the independent origin of fusellar and cortical tissue suggested by Kozlowski,each being secreted by a different part of the body, the ultrastructural data are indicative of a uniform mode of secretion. A secretion of the entire periderm within an epithelial evagination - the perithecal membrane - appears to be more readily compatible with the ultrastructural studies. Substantial differences in fabric, pattern, and mode of secretion of fusellar ex­ tracellular tissues in pterobranchs and graptolites produce serious obstacles for homo­ logy between them. Accordingly, there is little reason to suggest an immediate phylogenetic relationship between pterobranchia and Graptolithina. The systematic position of the ratter group within the Bilateria remains an unresolved problem.

Journal ArticleDOI
04 Nov 1976-Nature
TL;DR: Gobipteryx minuta is the oldest known palaeognathous bird, the earliest hitherto recorded fossils of this group being of Eocene age as mentioned in this paper, and is estimated to be 45 mm long, which is roughly the size of a partridge.
Abstract: Two skulls of an unquestionably palaeognathous bird were found by the Polish–Mongolian Palaeontological Expedition to the Gobi Desert1. Both specimens originate from the same locality, the beds being referred to as Barun Goyot Formation (?Campanian2). One skull, badly damaged, has been described as Gobipteryx minuta and the new order Gobipterygiformes has been allocated tentatively to the Palaeognathae3. Examination of the second, better preserved, although incomplete skull has now confirmed this allocation. Thus, Gobipteryx is the oldest known palaeognathous bird, the earliest hitherto recorded fossils of this group being of Eocene age4. I estimate the skull of Gobipteryx to be 45 mm long, so that the bird was roughly the size of a partridge.