Showing papers by "University of Warsaw published in 1969"

Theory of filters

Abstract: We consider the following statistical problem: suppose we have a light beam and a collection of semi-transparent windows which can be placed in the way of the beam. Assume that we are colour blind and we do not possess any colour sensitive detector. The question is, whether by only measurements of the decrease in the beam intensity in various sequences of windows we can recognize which among our windows are light beam filters absorbing photons according to certain definite rules? To answer this question a definition of physical systems is formulated independent of “quantum logic” and lattice theory, and a new idea of quantization is proposed. An operational definition of filters is given: in the framework of this definition certain nonorthodox classes of filters are admissible with a geometry incompatible to that assumed in orthodox quantum mechanics. This leads to an extension of the existing quantum mechanical structure generalizing the schemes proposed by Ludwig [10] and the present author [13]. In the resulting theory, the quantum world of orthodox quantum mechanics is not the only possible but is a special member of a vast family of “quantum worlds” mathematically admissible. An approximate classification of these worlds is given, and their possible relation to the quantization of non-linear fields is discussed. It turns out to be obvious that the convex set theory has a similar significance for quantum physics as the Riemannian geometry for space-time physics.

Observations on the origin of the ‘germinal cytoplasm’ in Xenopus laevis

Abstract: The early appearance of the ‘germinal cytoplasm’ and its behaviour during the formation of cells which are thought to represent the primordial germ cells have been described in detail for Rana temporaria by Bounoure (1927, 1934, 1939) and Blackler (1958). These observations were extended to Xenopus laevis (Nieuwkoop, 1956; Nieuwkoop & Faber, 1956; Blackler, 1958), Bufo bufo (Blackler, 1958), Rana pipiens (Berardino, 1961), Discoglossus pictus (Gipouloux, 1962 a ) and Rana esculenta (Hammer, cited by Blackler, 1965 b ). The above findings agree with respect to the earliest detection of the ‘germinal cytoplasm’. Its first appearance was noticed as early as in the fertilized, unsegmented egg, where small, distinctly staining islands of cytoplasm are localized just under the cell membrane in an area around the vegetative pole of the egg. During cleavage the ‘germinal cytoplasm’ is distributed between the vegetative blastomeres directly surrounding the vegetative pole.

Some accurate results for three-particle systems

Abstract: Results of a variational calculation of the nonadiabatic ground state energy of H 2 + are presented. Diagonal corrections for nuclear motion have also been calculated for the electronic ground state of H 2 + . The adiabatic potential energy curve has been employed to calculate the rotational and vibrational levels for the H 2 + ion and for muonic molecules. Nonadiabatic energy corrections are discussed. Forpμd the adiabatic wave function is compared with the corresponding nonadiabatic result.

Chromosome Preparations from Mouse Embryos During Early Organogenesis: Dissociation After Fixation, Followed by Air Drying

Abstract: Embryos are put into 1% sodium citrate at 37 C; 7– and 8-day specimens requiring about 20 min. With increasing age, the duration of treatment is increased up to 50 min. Handling is facilitated by keeping specimens in a small glass vessel for observation under a binocular microscope, and by changing fluids with a fine-tipped pipette. Fixation in ethanol-acetic acid 3:l for 2–3 hr is uncritical, as material may be stored in the fixative overnight at 4 C. Staining in toto with 2% orcein in 50% acetic acid follows, requiring 0.5–1 hr (storage in this solution up to 2 wk at 4 C is permssible). After staining, specimens are subjected to cellular dissociation in a mixture of glacial acetic and 50% lactic acid, the action of which is controlled by the duration of treatment and by increasing the ratio of lactic to acetic from 1:Z (younger embryos) to 3:2 (older embryos). Only 1–3 drops of the dissociating fluid is used for each embryo, to favor concentration of the free-floating cells. Since the time required vari...

Comparison of RNA's transcribed in vivo from mitochondrial DNA of cytoplasmic and chromosomal respiratory deficient mutants

Abstract: In some respiratory deficient cytoplasmic mutants, the buoyant density of mitochondrial DNA is changed to detectable degrees, as compared to that of wild type strain: since this density shift suggests an important modification of polynucleotide sequence in mitochondrial DNA, we examined sequence homology between mitochondrial DNA of the respiratory mutants issued from cytoplasmic or chromosomal mutations. Mitochondrial DNA, nuclear DNA and total RNA were extracted from ϱ+ cells (wild type, respiratory sufficient) and from ϱ- cells (cytoplasmic “petite colonie” mutant, respiratory deficient), and molecular hybridization experiments were carried out between them. When ϱ+ RNA × ϱ+ mitochondrial DNA, formed roughly twice as much hybrids as the heterologous cross, ϱ+ RNA × ϱ1 mitochondrial DNA. Reciprocally, when ϱ- RNA was hybridized to ϱ+ and ϱ- mitochondrial DNA, the homologous cross produced again about twice as much hybrids as the heterologous cross. These results were confirmed by dehydridization-rehybridization experiments: the RNA separated from the hybrids “ϱ+ RNA × ϱ+ mit-DNA” as well as the RNA separated from the hybrids “ϱ+ RNA × ϱ- mit-DNA” were rehybridized either with ϱ+ or ϱ- mit-DNA. A preferential hybridization of ϱ+ RNA with ϱ+ mit-DNA, and of ϱ- RNA with ϱ- mit-DNA was clearly observed. On the contrary, ϱ+ and ϱ- nuclear DNA did not distinguish ϱ+ or ϱ- RNA. The same series of experiments were carried out using a chromosomal mutation,P 7 to p7, leading to the same respiratory deficient phenotype. We found that the p7 mutation did not introduce a detectable change in mitochondrial DNA base sequence. The results support the idea that the cytoplasmic hereditary factor, ϱ, resides in mitochondrial DNA and that the ϱ- mutations studied correspond to a dispersed sequence modification covering about a half of the total mitochondrial DNA genome, leaving the other half unchanged. Alternatively, the results can be explained by a hypothesis in which mitochondrial DNA is a heterogeneous population of the molecules having more or less related sequences and the mutation leads to a selection of certain molecular species. 4 S RNA was found to contain RNA species which hybridize with mitochondrial DNA. The degree of hybridization was very different for ϱ+ and ϱ- S RNA, when they were hybridized with either ϱ+ or ϱ- mitochondrial DNA.

Departments of Psychology: Neuropsychology in Neurological Rehabilitation

Abstract: In 1962 the Neurological Clinic of the Medical Academy in Warsaw initiated the creation of the Centre for Neurological Rehabilitation, in Konstancin-near-Warsaw (Poland). At first the Centre dealt mainly with motor rehabilitation of patients after brain stroke, but it soon became obvious that, if the process of rehabilitation were to be as efficient and complete as possible, it is necessary to carry out rehabilitation of the higher functions, for example speech, which are often disturbed after brain damage. Therefore the Centre began to cooperate with the Department of Psychology of the Warsaw University, where research in the field of neuropsychology has been carried out for some years. The agreement that followed provided for the setting-up of the Team for Therapy of Higher Functions, which grouped scientists from the Centre as well as scientists and students from the Department who are specialized in neuropsychology. At the same time neuropsychologists from the Polish Academy of Sciences Resea...

Inhibitors Around the Antimycin-Sensitive Site in the Respiratory Chain

Abstract: The region of the respiratory chain between cytochromes b and c1 is affected by several compounds in such a way as to lead to inhibition of electron transport. The site of action of these inhibitors is usually called the “antimycin-sensitive” site because antimycin [1] is the most firmly bound. Three main classes of inhibitors will be considered here: (i) antimycin, (ii) alkyl derivatives of 4-hydroxyquinoline-N-oxide and (iii) alkyl derivatives of 3-hydroxy-1,4-naphthoquinone. Their application in studies on the structure and function of the respiratory chain has been manyfold: (a) in elucidation of the sequence of the components [58], (b) in reconstitution of the respiratory chain [39], (c) in oxidative phosphorylation [59] especially in estimating the sites of phosphorylation and (d) in studies on the reversal of the respiratory chain [33, 41].

Fate of primordial germ cells in the transplanted hind gut of mouse embryos.

Abstract: During normal development of the mouse embryo, primordial germ cells (PGCs) differentiate in the root of the allantois and in the hind region of the embryo, then pass to the hind gut and through the mesentery to reach the germinal ridges (Chiquoine, 1954; Bennett, 1956; Mintz & Russell, 1957; Mintz, 1957; Ozdzenski, 1967). The number of PGCs increases greatly during migration (Chiquoine, 1954; Mintz & Russell, 1957). After penetrating into the gonads PGCs continue to divide mitotically for a certain time, then undergo changes which differ in each sex: the meiotic prophase begins in the ovaries (Brambell, 1927; Borum, 1961), gonial divisions are arrested in the testes and the chromatin in the nuclei of the germ cells undergoes characteristic dispersion. The behaviour of germ cells in the male embryos of the mouse is similar to that described by Clermont & Perey (1957) and Beaumont & Mandl (1963) in the rat.

On the generalized Saletan contractions

Abstract: The generalized Saletan contractions leaving some subalgebra unchanged are investigated. By use of a simple basis the necessary and sufficient conditions for these contractions and the brackets of the contracted algebra expressed only by the structure constants of the algebra to be contracted are obtained. Many basis independent results are derived. Some of them give as a special case Saletan results. Similar contractions but for e → ∞ are proposed and investigated.

Influence of Additional Illumination on the Photoemission from n‐ and p‐Type Gallium Arsenide Single Crystals

Abstract: A study was made of the photoemission of electrons from oriented monocrystals of GaAs with special reference to the effect of additional infrared illumination. The retarding potential method was used in a spherical capacitor arrangement. The current-voltage characteristics of n-type material shift to the right upon additional illumination, while those of the p-type material shift to the left. The shift is weaker for the p-type samples, for which also the saturation current diminishes with illumination. These effects are explained by the change of the curvature of the energy bands near the surface with illumination. Es wurde die Photoemission von Elektronen aus orientierten GaAs-Einkristallen unter spezieller Berucksichtigung einer zusatzlichen Infraroteinstrahlung untersucht. Dabei wurde die Methode der retardierten Potentiale in einer Kugelkondensatoranordnung benutzt. Die Strom-Spannungs-Charakteristiken von n-leitendem Material verschieben sich nach zusatzlicher Einstrahlung nach rechts, wahrend sie sich bei p-leitendem Material nach links verschieben. Fur p-leitende Proben ist die Verschiebung schwacher, und es verschwindet auch der Sattigungsstrom bei Einstrahlung. Dieser Effekt wird durch die Anderung der Krummung der Energiebander in der Nahe der Oberflache mit der Einstrahlung erklart.

Infrared Absorption by Local Vibrational Modes of Boron Impurities in Germanium

Abstract: Local modes of boron in germanium have been observed by infrared absorption measurements in the range from 480 to 630 cm−1 at 195 and 295°K. Lithium has been used as a compensating donor impurity. The absorption spectrum contains three pairs of bands which are attributed to local modes of boron on the basis of the isotopic shifts observed. One of these pairs is associated with unpaired (isolated) boron and two others with boron in paired configuration (with lithium), as was predicted theoretically. A comparison of our data with those already known for silicon is given.

Photometric Observations of the Peculiar Blue Variable TT ARI = BD + 14°341

Abstract: Light variations of BD +14°341 can be resolved into three, apparently independent activities: (1) periodic variations with P = 0.d2658 and an amplitude of about 0.15 mag.; (2) quasi-periodic fluctuations with periods between 14 and 20 minutes and variable amplitude; and (3) small-scale, apparently irregular fluctuations (“flickering”) with a time-scale of the order of 1 min. It is suggested that the star is a hot, subluminous close binary system.

Solar-wind model including the effects of rotation, magnetic fields, and anisotropic heat conduction.

Abstract: A time-independent solar-wind model is considered in the case of spherical symmetry and of radial magnetic field at the sun’s surface. The energy equation includes besides the usual terms also the heat conduction and magnetic-energy convection (Poynting vector) terms. The dependence of the thermal conductivity on the magnetic field is taken into account. Numerical integrations of the basic equations were performed under the following assumptions: (i) close to the sun the magnetic field is the dominant azimuthal term and solid-body rotation is enforced; (ii) beyond the Alfvenic point the terms quadratic in B are neglected. The model leads to azimuthal velocity at earth between 0.6 and 2.7 km/sec, to radial velocity at earth between 350 and 500 km/sec, and to angular momentum loss of 5 × 1018 cm2/sec per unit mass of gas leaving the solar equator. The dependence of the solutions on the reduction of the effective thermal conductivity caused by the micro-structures in the solar wind suggests that the conditions at earth may be largely determined by a transition region in the solar wind, in which the conduction regime changes into an almost adiabatic flow.

The origins of western and eastern Slav towns

Abstract: One of the most controversial problems exercising historians in the period between the two world wars was the origin of the towns of Central and Eastern Europe, especially those of Poland and Ruthenia.1 Research into this question continued for many years to be exclusively the domain of historians, to be joined towards the end of the nineteenth century and the beginning of the twentieth by historians of law. For some time these last managed to impose their opinions on many of the current investigators. Starting from the assumptions of their own discipline, they claimed that the initial birth of towns in the region under discussion might be determined by establishing the date of the assigning of so-called 'town rights' to well-defined centres. Thus, for example, in Polish conditions this moment might in many cases have been the date of the investing of a rural settlement centre with the code known as the Magdeburg Law. The conclusion followed that the origins of the Polish towns could date back no further than the middle of the thirteenth century, resulting from German colonization, and first inhabited chiefly by settlers attracted to Poland from Germany by Polish sovereigns. This legal and dogmatic opinion concerning the origin of medieval towns was already opposed as early as 1893 by J. Flach, to be followed early in the 'twenties of our century by K. Tymieniecki. Among western scholars the eminent Belgian historian H. Pirenne expressed a similar view regarding the Slav towns. But the scarcity of written sources concerning the Slav towns in the period before the thirteenth century made a wider discussion of their beginnings impossible. Only with the development of archaeological research, growing considerably in the 'thirties of this century and particularly intensified during the last twenty years, could a new outlook on this exceedingly interesting problem become possible, opening new perspectives both in the history of early medieval Europe in general and in the development of Poland and the eastern Slavs in particular. Excavations carried out on many sites in