In the course of monitoring interplanetary scintillations of a large number of sources using the Big Scanning Antenna of the Lebedev Physical Institute, a search for pulsars with periods ≥0.4 s at declinations −9◦ < δ < 42◦ and right ascensions 0h < α < 24h was simultaneously carried out. The search was conducted using four years of observations carried out at 110.25MHz in six frequency channels making up a 2.5 MHz band and having a time resolution of 100 ms. The initial identification of pulsar candidates was done using Fourier power spectra averaged over the entire observational period; the pulsar candidates were then verified using observations with higher frequency and time resolution: 32 frequency channels and a time resolution of 12.5 ms. Eighteen new pulsars were discovered in the studied area, whose main characteristics are presented.

Contech Cryogenics is a small firm focused largely on specialist centrifugal and piston pumps for handling cryogenic liquids such as liquid oxygen. Director general Igor Nikitin provides the details.

The theory of relativistic strings is considered in frames of Hamiltonian formalism and Dirac's quantization procedure. A special gauge fixing condition is formulated, related with the world sheet of the string in Lorentz-invariant way. As a result, a new set of Lorentz-invariant canonical variables is constructed, in which a consistent quantization of bosonic open string theory could be done in Minkowski space-time of dimension $d=4$. The obtained quantum theory possesses spin-mass spectrum with Regge-like behavior.

We perform a quantization of 4-dimensional Nambu-Goto theory of open string in light cone gauge, related in Lorentz-invariant way with the world sheet. This allows to obtain a quantum theory without anomalies in Lorentz group. We consider a special type of gauge fixing conditions, imposed in oscillator sector of the theory, which lead to a relatively simple Hamiltonian mechanics, convenient for canonical quantization. We discuss the algebraic and geometric properties of this mechanics and determine its mass spectrum for the states of spin singlet S=0.

Real-time visibility test is an attractive feature for Virtual Environment (VE) applications where large datasets should be interactively explored. In such scenes most of the objects are usually occluded by other ones, and their rejection from rendering can significantly accelerate the graphical performance. In this paper we present our implementation of occlusion culling in VE system Avango [1]. Visibility test module performs real-time update of the list of visible objects by means of color labeling and either hardware or software histogramming of corresponding color buffer. Exploiting the distribution capabilities of Avango, the main draw and visibility test processes are parallelized to different computers running Irix or Linux. Being applied to an architectural model containing 260,000 textured triangles, our method accelerates the graphical performance from 8 to 32 stereoimages/sec.

We develop two numerical methods to solve the differential equations with deviating arguments for the motion of two charges in the action-at-a-distance electrodynamics. Our first method uses Sturmer's extrapolation formula and assumes that a step of integration can be taken as a step of light ladder, which limits its use to shallow energies. The second method is an improvement of pre-existing iterative schemes, designed for stronger convergence and can be used at high-energies.

Numerical methods for solution of differential equations with deviating arguments describing 1-dimensional ultra-relativistic scattering of 2 identical charged particles in classical electrodynamics with half-retarded/halfadvanced interaction (Wheeler and Feynman, 1949) are developed. A bifurcation of solutions and violation of their reflectional symmetries in the region of velocities v>0.937c are found in numerical analysis.

A theory of closed bosonic string in time-like gauge, related in Lorentz-invariant way with the world sheet, is considered. Absence of quantum anomalies in this theory is shown.

The problem of 1-dimensional ultrarelativistic scattering of 2 identical charged particles in classical electrodynamics with retarded and advanced interactions is investigated.

Solutions of classical string theory, corresponding to the world sheets, mapped in Minkowski space with a fold, are considered. Typical processes for them are creation of strings from vacuum, their recombination and annihilation. These solutions violate positiveness of square of mass and Regge condition. In quantum string theory these solutions correspond to physical states |DDF〉 + |sp〉 with non-zero spurious component.

In the phase space of an open bosonic string, finite-dimensional submanifolds that admit anomaly-free quantization in d = 4 are studied.

The quantum string theory in the indefinite (pseudo-Hilbert) Fock representation is considered. It is shown that all anomalies in the four-dimensional theory of an open bosonic string are canceled for a particular choice of the vacuum state. Then the algebra of the reparametrization symmetry (in the covariant approach) and the algebra of rotations (in the light-cone gauge) become closed. The indefiniteness of the space of states leads to some nonphysical properties of the theory. Modifications of the model under consideration, which are necessary to construct a more realistic theory, are discussed.

This paper considers application of visualization to research on singular points on the world sheets of relativistic strings. We consider a method of representing world sheets that permits them to be effectively investigated with three-dimensional visualization. The images thus obtained for world sheets in three- or four-dimensional space make it possible to provide a detailed classification of their singularities.