Polyspectral analysis and optimization of the frequency-domain differential phase-shift keying

Using the mathematical tool of high-order spectra (polyspectra), we consider the synthesis of optimal variants of high-order differential phase-shift keying in the frequency domain. The proposed approach allows all possible variants of the second-order differential phase-shift keying to be reduced to phase modulation of a special form of the fourth-order spectrum (trispectrum) — triphase modulation. The optimal triphase shift keying variants which have the best spectral efficiency and outperform the known variants of the second-order differential phase-shift keying in noise immunity are devised. It is shown that the noise immunity of proposed modulation is higher than that of the first-order differential phase-shift keying in the channels with simultaneous time and frequency offsets.     

On amplifications of photonuclear neutron flux in thunderstorm atmosphere and possibility of detecting them

The reliability of communications reporting observations of neutron flux enhancements in thunderstorm atmosphere is analyzed. The analysis is motivated by the fact that the employed gas-discharge counters on the basis of reactions ³He(n, p)³H and ¹⁰B(n; ⁴He, γ)⁷Li detect not only neutrons but any penetrating radiations. Photonuclear reactions are capable of accounting for the possible amplifications of neutron flux in thunder-storm atmosphere since in correlation with thunderstorms γ-ray flashes were repeatedly observed with spectra extending high above the threshold of photonuclear reactions in air. By numerical simulations, it was demonstrated that γ-ray pulses detected in thunderstorm atmosphere are capable of generating photonuclear neutrons in numbers sufficient to be detected even at sea level.     

Numerical simulation of narrow bipolar electromagnetic pulses generated by thunderstorm discharges

Using the concept of avalanche relativistic runaway electrons (REs), we perform numerical simulations of compact intracloud discharge (CID) as a generator of powerful natural electromagnetic pulses (EMPs) in the HF-VHF range, called narrow bipolar pulses (NBPs). For several values of the field overvoltage and altitude at which the discharge develops, the numbers of seed electrons initiating the avalanche are evaluated, with which the calculated EMP characteristics are consistent with the measured NBP parameters. We note shortcomings in the hypothesis assuming participation of cosmic ray air showers in avalanche initiation. The discharge capable of generating NBPs produces REs in numbers close to those in the source of terrestrial γ-ray flashes (TGFs), which can be an argument in favor of a unified NBP and TGF source.     

Comparative Pharmacokinetics and Relative Bioavailability of a New Anxiolytic GML-1 in Tablet Form

Moscow University Chemistry Bulletin - An open, single, crossover, pharmacokinetic study of GML-1 (dose 50 mg/kg) in rabbits after its oral administration in tablets and alone as a substance is...     

Synthesis of orthobenzoates of β-L-arabinofuranose

Conclusions The synthesis of bicyclic and tricyclic orthobenzoates of-L-arabinofuranose has been described.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2030–2032, November, 1966.The authors are grateful to G. N. Artemova (NIOKh SO AN SSSR [Novosibirsk Institute of Organic Chemistry, Siberian Division, Academy of Sciences of the USSR, Novosibirsk]) for determining the molecular weight of the 1,2,5-O-orthobenzoyl--L-arabinofuranose.