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An experiment devoted to studying neutron–neutron angular correlations in the slow-neutroninduced fission of 233U, 235U and 239Pu nuclei was performed. The experimentally determined angular dependence of the number of neutron–neutron coincidences was compared with the results of a Monte Carlo simulation for various values of the neutron-detection threshold in the range between 490 and 2080 keV. It was found that the experimental angular distributions in question can be described well under the assumption that 2% to 5% of all prompt fission neutrons are emitted isotropically in the laboratory frame. Probably, such neutrons can be interpreted as so-called scission neutrons directly associated with the nuclear-rupture instant. Energy distributions of this component were also obtained from the present analysis.

We consider a general approach to approximate studies of optimal control problems on the abstract level with various representations and transformations of the object model, extension principles, localizations, sufficient optimality conditions, and on the qualitative level, the search for an approximate globally optimal control. Here we use and develop transformation methods for degenerate problems that are characteristic for applications in various domains. The resulting solution can serve as an initial approximation in subsequent iterative optimization procedures whose construction methods and properties are considered in the second part of the paper.

A case of late manifestation ofmucoviscidosis is reported. In the past, this pathology was dealt with by pediatricians, but to-day the management of this problem involves a number of different specialists. The progress in clinical practice makes it possible to significantly prolong the life span of patients with this condition. The present case shows that its clinical manifestations may appear at any age.

Neutron angular distributions in spontaneous fission of 252Cf are investigated. The CORA experiment, performed at IPHC Strasbourg, aims at elucidating neutron emission mechanisms in the fission process. The experimental setup is composed of the angle-sensitive twin ionisation chamber CODIS for the detection of fission fragments and the DEMON neutron detector assembly. The development of a simulation toolkit based on GEANT4 and MENATE_R is described, adapted as a strategy to investigate the influence of experimental conditions on the observed properties of neutrons emitted. Besides the kinematic neutron anisotropy in the laboratory system due to neutron evaporation from moving fragments, two additional effects are discussed which may have an influence on the angular distributions of neutrons: scission neutrons and dynamic neutron emission anisotropy in the CM system of fragments due to the spin carried by fragments. A new analysis method is presented to disentangle the dynamic anisotropy from the other effects in an independent way. For the dynamic anisotropy only an upper limit could be found. Results for the angular correlation $ (\mathrm{n},\mathrm{n})$ between two evaporated neutrons and the correlation $ (\mathrm{n},\mathrm{LF})$ between an evaporated neutron and the Light Fragment direction of flight are reported.

An experiment has been performed at IPHC Strasbourg, aimed at the detailed investigation of angular correlations in the neutron emission from spontaneous fission of 252Cf. Fission fragments were measured by the angle-sensitive double ionization chamber CODIS while neutrons were detected by a set of 60 DEMON scintillator counters. The main aim of the experiment is the observation of the correlation between the fragment spins and neutron emission anisotropy. Preliminary results, based on the Monte-Carlo simulations, as well as the preliminary analysis of the experimental data are shown.

A case of late manifestation ofmucoviscidosis is reported. In the past, this pathology was dealt with by pediatricians, but to-day the management of this problem involves a number of different specialists. The progress in clinical practice makes it possible to significantly prolong the life span of patients with this condition. The present case shows that its clinical manifestations may appear at any age.

Experimental neutron distributions have been investigated in the spontaneous fission of 252Cf at IPHC in Strasbourg. The CORA experiment associating the CODIS twin ionisation chamber and the neutron multi-detector DEMON aimed to solve an long-standing problem in fission: the possible emission of scission neutrons and/or the presence of a dynamical anisotropy in the neutron evaporation by the moving fission fragments. A new method allowing to establish the dynamical anisotropy in an independent way is presented. The results obtained from a comparison with simulations based on GEANT4 are shown., SCOPUS: cp.p, info:eu-repo/semantics/published

We consider a singularly perturbed boundary value problem for a differential equation with a retarded and a deviating argument. By using the method of boundary functions and the sewing method, we find not only a continuous but also a smooth solution of the problem. We prove the existence of a solution with an internal transition layer. A graphical numerical example is presented.

We present first results of the photometric and spectroscopic investigation of the B1/B2 Herbig star HD52721 performed in 2009–2010 at three observatories: Mountain Astronomical Station (Kislovodsk)—photometry, CrAO (Crimea, Ukraine)—spectroscopy, Observatory San Pedro Martyr (Ensenada, Mexico)—high-resolution echelle-spectroscopy. We have also used photometric data from the ASAS survey for 2003–2009. Our analysis has shown that a) the object is a close binary system with the orbital period of 1.610 days composed of two components of similar spectral type (B1–B2); b) the system is surrounded by the common disk-like envelope containing azimuthal inhomogeneity rotating with the orbital period of the system. We present preliminary estimates of the system parameters and discuss its possible nature.

Photometric and high-resolution spectral data on the Be Herbig star HD 52721 from our earlier article [1] are supplemented by new data obtained with an echelle spectrograph mounted on the 2.1-m telescope at the San Pedro Martir Observatory (Ensenada, Mexico). BVR photometry data obtained during 1987-1998 at the Maidanak Observatory (Uzbekistan) are also examined in more detail. This confirms that the phase light curve for an orbital period P = 1d.610 has two minima with different depths separated in phase by 0.5, and reveals a reddening of the object at the phases of the minima. The profiles of atmospheric He I lines in the 4000-4500 A range are found to be broader, shallower, and more asymmetric at the brightness maximum than at the minimum, as expected in close binary systems. Various factors which may influence the formation of the observed atmospheric line profiles are discussed. The observations confirm the hypothesis of a dense disk shaped gas envelope surrounding the system that makes a significant contribution to its overall brightness and contains a global azimuthal inhomogeneity rotating in synchrony with the orbital motion of the system components. We emphasize the need for new photometric observations of HD 52721 in the region of the atmospheric lines, as well as a continuation of the photometric program, in order to confirm the existence of and to analyze the stable, small variations in the light curve of this object.

The main results of studying the properties of “instantaneous” neutrons and γ photons during the fission of 233, 235U(nth, f) and 239Pu(nth, f) nuclei and spontaneous fission of 252Cf, which were performed on the WWR-M reactor at the St. Petersburg Nuclear Physics Institute, Russian Academy of Sciences, are presented. Along with obtaining the main characteristics of the instantaneous radiation from fission fragments, these studies were also aimed at gaining deeper insight into such exotic processes as the emission of break neutrons and γ photons from a fissioning nucleus near the break point. These investigations were performed on different experimental setups using different analytical methods. This approach allowed us not only to find but also to reduce to minimum possible systematic effects. The yields of break neutrons were found to be about (5–7) × 10−2 of the total number of neutrons per 233, 235U(n, f) fission event and approximately twice as much for 239Pu(n, f) and 252Cf. The coefficient of T-odd asymmetry for γ photons is in agreement with the estimate obtained on the assumption that the observed effect is mainly related to the γ photons emitted by excited fragments with highly oriented angular momenta. This fact gave grounds to conclude that the desired break γ photons cannot be reliably selected (within the obtained experimental accuracy) against the much larger background of γ photons from fission fragments.

The new physical effects of T-odd asymmetry of the emission of light charged particles (LCPs) during the ternary fission of some heavy nuclei by cold polarized neutrons have been experimentally studied. The coefficients of triple scalar and vector correlation of the pulses of light particles and fission fragments (TRI effect) and the fivefold correlation of the same vectors (ROT effect) have been measured. These effects are believed to be caused by the rotation of polarized fissioning system around its polarization direction. The treatment of the experimental data for LCPs in the framework of this hypothesis leads to a good agreement between the calculation results and experimental data. The calculated value of the angle of rotation of the fission axis in the ternary fission of the polarized fissioning 236U* compound nucleus was used to process the results of measuring the ROT effect for γ photons from binary-fission fragments of the same nucleus. A satisfactory description of these experimental data is obtained which serves a convincing confirmation of the rotation hypothesis.

Consideration was given to optimization of the regional development strategy with the use of an aggregated ecologo-economic model allowing for the constraints on the nature-regenerating and innovation powers. The control actions were represented by presumably unlimited investments providing as the result a turnpike solution meeting the stable development criterion. Realization of the solution was described, and a numerical example presented.

Photometric and high resolution spectroscopic data for the Herbig star HD 52721 obtained from October 2009 through October 2010 are presented. We confirm the cyclical character of the photometric variability of HD 52721 discovered previously by others. The variability shows up as minima in the light curve of this star which repeat with a period P = 0d.805 and are typical of eclipsing binary systems. ASAS data covering an observation period from September 2003 through December 2009 show that two neighboring photometric minima differ from one another, and the actual orbital period of the system must be twice as high (P = 1d.610). This is confirmed by the spectroscopic data. These show that the center of gravity of the emission Hα line and the profile of the HeI 6678 line with a distinct, bright circumstellar component have a clear correlation with a period of 1d.610. To all appearances, HD 52721 is a close binary system consisting of two class B2 stars with quite similar parameters. We propose that the observed cyclical variations in the circumstellar parameters may be related to the existence of a global azimuthal inhomogeneity within the shell which rotates synchronously with the orbital motion of the system components.

The angular dependence of the γ-ray asymmetry relative to the plane formed by the directions of fission-fragment separation and longitudinal polarization of the thermal neutrons inducing 235U(n, f) fission was investigated. The results obtained confirm the existence of γ-ray emission asymmetry and the dependence of its coefficient on the angle between the axes of the fission-fragment and γ-ray detectors, revealed for the first time by the ITEP group at the FRM-II reactor in Munich. The observed T-odd effect of around ∼2 × 10−4 can be explained by the angular anisotropy of the γ-ray emission from fission fragments with large angular momenta oriented relative to the fission axis.

Prospects for further studies of TRI and ROT effects of T-odd asymmetry in the emission of light particles in the ternary and binary fission of heavy nuclei that is induced by slow polarized neutrons are considered with a view to studying the mechanism for the formation of these effects and using them to get new information about fission dynamics. It is planned to investigate the dependence of the corresponding T-odd-asymmetry coefficients on the main characteristics of the fission reaction.

To estimate the main characteristics of neutrons emitted shortly before the scission of a fissioning nucleus, various experiments sensitive to the presence of these scission neutrons in thermal-neutron-induced fission of 235U and spontaneous fission of 252Cf were performed. The results of the experiments were analyzed within theoretical calculations allowing for various possible neutron-emission mechanisms, including the possibility of the emergence of neutrons from the scission of a nucleus.

An experiment has been carried out to study neutron-neutron angular correlations in spontaneous fission of 252Cf. Angular dependences of the number of neutron-neutron coincidences obtained in the experiment were compared with the results of the Monte Carlo calculations for various neutron detection thresholds in the range 425–1600 keV. It was inferred that 10–11% of the total number of prompt neutrons from 252Cf (s.f.) in the laboratory system were emitted isotropically and may probably be interpreted as neutrons directly associated with the instant of scission of the nucleus. The analysis allowed their energy distribution to be determined as well. A similar method was also used to describe the angular correlation of prompt neutrons that accompanied the reaction 235U(n th ,f).

A triple T-odd angular correlation is considered in the kinematically similar reactions 10B(n, αγ) and 233U(n, αf) induced by cold polarized neutrons. It is shown that, in the former reaction, this correlation is suppressed by the double parity-conservation selection rule due to the two-step character of the process; however, T invariance does not impose any specific constraints on this correlation. The mechanism through which the T-odd correlation found in ternary-fission reactions is formed seems to be closely related to a nearly simultaneous disintegration of the nucleus involved into two fission fragments and an alpha particle.

Three interference asymmetry effects in the angular distributions of fragments originating from 233U fission induced by resonance neutrons were measured. The energy dependences of the asymmetry factors being studied show sizable irregularities that are associated, according to modern theory, with the interference of s and p resonances at the stage of a compound nucleus. The basic features of weak p-wave resonances in the low-energy region were obtained from a global theoretical analysis of the asymmetry factors as functions of energy. The first estimates of nuclear matrix elements of weak interaction were derived for a few p-wave resonances.

These investigations were performed to test the modern theory and to obtain first estimates of nuclear matrix elements of weak interaction and the main parameters of p -resonances. Combined investigations of the space parity non-conservation effect of 235 U fission fragment emission and the interference effects of the forward-backward and left-right asymmetries were carried out over the range of neutron energies from 0.02 eV to 90 eV. The experimental results are found to be in good agreement with the theory. The first estimates of the nuclear matrix element of the weak interaction for three p -resonances and the main parameters of some low energy p -wave resonances are obtained from a combined theoretical description of all experimental data.

The worldwide application of CCDs in astronomy is concerned mainly with the problems of photometry and spectrophotometry. Astrometry with CCDs is limited by the small fields of view and now is used to solve some special tasks such as parallax determination of faint stars, observations of QSOs, etc. Very interesting results were obtained using a CCD with a meridian circle in a drift scanning mode to solve the problem of the extension of the reference system to stars of 16th–17th mag and the linkage between radio and optical reference frames (Stone 1994).Based on the preliminary results of our observations, some proposals on astrometry with CCDs are discussed in the paper. The aim is to show the use of short-focus telescopes with CCDs in the mode of traditional astrographs. Numerous tasks may be solved with such instruments more simply and correctly than with meridian instruments in a drift scanning mode.The problems of the application of CCDs with short-focus optics are also discussed. Some effects of CCD properties on the accuracy of astrometric and photometric measurements are also considered.

During a week of the March maximum in 2011, two oppositely installed direction-sensitive TEU-167d Dark Electron Multipliers (DEMs) recorded a flux of daemons from the near-Earth almost circular heliocentric orbits (NEACHOs). The flux measured from above is f \approx (8\pm3)\times10^-7 cm^-2 s^-1, and that from below is twice smaller. The difference may be due both to specific design features of the TEUs themselves, and to dissimilarities in the slope of trajectories along which objects are coming from above or from below. It is shown that the daemon paradigm enables a quantitative interpretation of DAMA and CoGeNT experiments with no additional hypotheses. Both the experiments record a daemon flux of f ~ 10^-6 cm^-2 s^-1 from strongly elongated Earth-crossing heliocentric orbits (SEECHOs), predecessors of NEACHOs. Recommendations are given for processing of DAMA/LIBRA data, which unambiguously suggest that, in approximately half of cases (when there occur double events in the detector, rejected in processing under a single-hit criterion), the signals being recorded are successively excited by a single SEECHO object along a path of ~1 m, i.e., this is not a WIMP. It is noted that due regard to cascade events and pair interaction of ions will weaken the adverse influence exerted by the blocking effect on the channeling of iodine ions knocked out in NaI(Tl) crystal. This influence will become not so catastrophic as it follows from simplified semi-analytical models of the process: one might expect the energy of up to ~10% of primary recoil iodine ions will be converted to the scintillation light., 15 pages, 2 figures

The formally T-odd triple correlation between the directions of the momenta of α particle and γ quantum and the polarization pseudovector of a thermal neutron was examined for the 10B+n=7Li+4He+γ reaction. Such T-odd correlations can be directly used for checking time reversal invariance in the elastic scattering of particles. In more complex reactions, this correlation can occur as a result of particle interactions in the entrance and exit channels of the reaction and, being a background effect, requires correct theoretical or direct experimental estimation. Our experiments gave an upper limit of 3.2×10−4 (90% confidence level) for the possible T-odd asymmetry parameter in the reaction under study.

In accordance with the PNPI Program of the fast neutron emission mechanism investigations in low excitation energy fission of heavy nucleus, the energy and angular distributions of neutron emission and angular dependence of (n‐n)‐ coincidences for different thresholds of neutron energy recording have been investigated in 252Cf(sf), 233,235U(n,f), and 239Pu(nf) fission. As a result of experimental data analysis performed on the assumption that the main part of neutrons are evaporated from the fully accelerated fragments with a big oriented angular momenta, the following figures for the yields of neutrons emitted before appearance of the fragments had been obtained for 252Cf(sf) and thermal neutron induced fission of 233,235U, and 239Pu: (10±2)%, (5±2)%, (7±2)%, and (10±2)% respectively.

Experimental neutron angular distributions are investigated in the spontaneous fission process of 252Cf. The CORA experiment, presented in this paper, has the aim to study neutron angular correlations in order to elucidate the neutron emission mechanisms in the fission process. The experimental setup is composed by the CODIS fission chamber and the DEMON neutron multidetector. The development of a simulation toolkit based on GEANT4 and ROOT adopted as strategy to investigate the emission of the neutrons is described. Preliminary results on the sources of the anisotropy, scission neutron emission and/or dynamical anisotropy, are shown.

Investigations of the space parity nonconserving (PNC) asymmetry of 233U, 235U, and 239Pu fission fragment emission and parity conserving (PC) interference effects of left‐right and forward‐backward asymmetries were carried out on the neutron beams of the reactor IBR‐30 (JINR, Dubna) over the range of neutron energies from 0.02 eV to about 100 eV. All experimental results obtained have been found to be in a good mutual accordance within the frames of modern theoretical conceptions about the mechanisms of PNC and PC effects forming in fission process induced by slow neutrons. In case of the P‐even interference effects of asymmetry the evident mutual well‐marked irregularities in their neutron energy dependencies up to about 100 eV were observed. It is connected with the interference of s, p‐resonances at fission compound stage according to modern theory. As a remarkable result of the PNC effect measurements the resonance behavior of the PNC asymmetry coefficients in the low neutron energy region (En < 2 eV) was observed. Unfortunately, the statistical accuracy of the PNC effect measurements is not enough for observation of these resonance effects in other cases of more high energies. Results of simultaneous analysis of all three asymmetry effects for all three nuclei are presented. The satisfactory combined description of the experimental points is received. As a result of theoretical evaluation of these data main parameters and the estimates of nuclear matrix elements of the weak interaction for some p‐resonances in the low energy range were extracted.

The worldwide application of CCDs in astronomy is concerned mainly with the problems of photometry and spectrophotometry. Astrometry with CCDs is limited by the small fields of view and now is used to solve some special tasks such as parallax determination of faint stars, observations of QSOs, etc. Very interesting results were obtained using a CCD with a meridian circle in a drift scanning mode to solve the problem of the extension of the reference system to stars of 16th – 17th mag and the linkage between radio and optical reference frames (Stone 1994).

Anomalous refraction remains to be the most critical problem in the meridian astrometry measuring large angles on the sky. I study slow quasi-periodical variations of refraction caused by the processes in the middle and upper atmosphere, such as gravity waves, etc., which can not be detected and calibrated out by use of any on-ground meteorological measurements. For this study, very old observations at large zenith distances of 80 to 90 degrees made by V. Fuss at Pulkovo Observatory in 1867–1869 [1] were used. The Deeming’s method [2] of spectral analysis of data was applied to examine the characteristic variations of refraction in a wide range of periods. Very powerful quasi-periodical processes with periods of 7–8, 11–14, 18–22, 36–44 minutes and with amplitudes of 0.3 to 0.5 arcsec in the zenith were found when short sets of observations (1–5 days) were considered. They increase random errors of astrometric observations with meridian circles, transit instruments, astrolabes, etc. The periods of very slow variations — 152, 122, 93, 82.5, 73, 61 and 50 days, — are close to the well known periods discovered in other astronomical phenomena, for instance, in solar activity and in Earth rotation. I note also, that some of the long-period variations of refraction may cause quasi-systematic errors in astrometric measurements and catalogues.

The main complication to use CCDs for astrometry is their small linear size. Nevertheless, a wide range of traditional astrometric problems can be solved by use of short-focus astrographs equipped with available CCDs. They are: creation of large astrometric and photometric catalogues, link of optical catalogues to an extragalactic reference frame, observations of the solar system bodies, etc. It can be shown that a telescope with focal length of 1–2 meters, equipped with a single CCD can produce a huge amount of simultaneous positional and photometric observations of high precision. It will be especially effective when the Tycho catalogue will be completed, because the problem of precise reference system in a small field of view (about 1 square degree) will be solved with extremely high accuracy. The majority of stars up to 18–20 magnitude can be observed with such an instrument. The problem of resolving ”close” stars arises only for some very dense areas on the sky, such as globular clusters etc. — The results of CCD-observations made at Pulkovo with a small short-focus astrograph (D=100 mm, F=712 mm, FOV=45 x 67 arcmin) in 1993–1994 show that the precision of single observation is not worse than: in right ascension — 0.15 to 0.35 arcsec, in declination — 0.10 to 0.25 arcsec (the size of pixel was 18 x 24 μm2), and in magnitude — 0.05 to 0.15 mag in a wide range of magnitudes from the brightest objects to V=16. From a series of 5–10 frames it is possible to obtain positions and magnitudes of a large number (up to 500–600 in one frame) of stars with a precision quite comparable with that of normal astrographs and other ”large” telescopes.

At the start of CCD observations one must investigate the metrological properties of the complex instrument: optics + CCD. One needs a densely spaced set of stars with precise coordinates and magnitudes. We first used the Pleiades catalogue by Eichhorn et al. (1970). Experimental observations were started at Pulkovo in 1993 using a very small refractor (D = 100 mm, F = 712 mm) equipped with a CCD ISD015A (520 x 580 pixels, 18 x 24 microns). The focal length of our astrograph provides an angular field of view of 45 x 67 arcmin (angular scale is 5.2 x 7 arcsec/pixel). With different exposures we can observe all stars with magnitudes from 2 to 16. The first observations were made to evaluate the accuracy of our positional and photometric measurements. Unfortunately, it appears that the catalogue of the Pleiades by Eichhorn is not good enough for this purpose because its epoch is very far from that of our observations and proper motions were not provided for the majority of the stars. The internal precision of our measurements (0.1–0.3 arcsec) allows us to determine the corrections to the stellar positions by Eichhorn et al. (1970)

The neutron total cross sections are measured with an accuracy △σ/σ ∼ 10−3 for Bi and Si in energy range from 1 eV to 100 eV and for 208Pb and C in the range from 1 eV to 10 keV using the time-off-light facility GNEIS in Gatchina. An estimated value of the neutron electric polarizability is αn=(2.6±1.4)·10−3 fm3.

The present-day realization of inertial coordinate system by means of traditional optical astrometry is the Fifth Fundamental Catalogue (FK5). The series of observations with new meridian instruments (CAMC, PMC-190, BAMC, HMC) show the significant correlated differences (up to 0.″1) of observational catalogues from the FK5. Moreover, FK5 mean epoch appears to be old (about 50 years ago) and FK5 proper motions would have essential errors owing to the fact that not many new original catalogues (only 25 in RA and 15 in DEC) were used when compiling FK5. It should be noted also that FK5 has a dissimilar accuracy of positions and proper motions of “old” and “new” stars.

1. The reaction of sodium acetylide with trialkylstannanol and hexaalkyldistannoxanes has been investigated and it has been shown that reaction takes place through the intermediate stage of the formation of stannanolates. 2. Unlike the stannanols, the trialkystannanolates readily react with trialkylethynylstannanes to form hexaalkyldistannylacetylenes. 3. In the reaction of sodium acetylide with trialkylstannanols, trialkylalkoxystannanes, and hexaalkyl-distannoxanes, the sodium atom at the acetylene bond is more active than the hydrogen atom.

In 22 human embryos and fetuses from 6 to 36 weeks of age successive formation of papillary patterns in the distal phalanges of the fingers have been studied. It has been stated that the papillary pattern begins forming with definition of its typical model, that is the central fragment of the pattern appears the first; the delta formation completes the process. The central fragment of the pattern is distinctly seen in the 16-17-week-old, and the delta-in the 22-24-week-old fetuses.

The light scattering method for investigation of structural and aggregate stability is proposed, based on the comparison between angle and time dependence of total intensity of scattering light and its depolarized component. The structural evolution of liposome is observed by the anisotropic light scattering method. It is shown that the sols aggregate stability violation follows the appearance and increase of small-scale defects of vesicules. The interpretation of light scattering data is confirmed by electron micrographs.

Dermatoglyphics was studied in 90 males suffering from chronic alcoholism to show a significant variability in the complex of dermatoglyphic indices, depending upon the clinical signs of the disease (differences in the degree of the disease progression, the presence of alcoholic psychoses, hereditary aggravation by alcoholism). All the male alcoholics showed a drop in the ridge density on the terminal phalanx of the fingers, compared to that of the control group. This phenomenon is of certain interest from the standpoint of diagnostic and prognostic significance and should be studied more thoroughly to have a deeper insight into its nature.