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First evaluations of the blackbody-radiation (BBR)-induced shift and broadening of highly excited Rydberg states were based on the account of only the first term of the expansion for the Planck's distribution in powers of the ratio of the BBR-photon energy to the environmental thermal energy. The corresponding asymptotic expression for the shift is proportional to a sum rule for the oscillator strengths, which is identical for all states, independently of their principal and angular-momentum quantum numbers. The broadening appeared proportional to the sum of the oscillator-strength first moments, which is dependent on only the principal quantum number, being independent of the state's angular momentum. In this article, we demonstrate that the account of higher-order terms of the Planck's distribution expansion provides corrections revealing the dependence of asymptotic shift and broadening on the Rydberg-state principal and angular-momentum quantum numbers. The strongest corrections are observed for states with low angular momenta, in agreement with earlier performed numerical calculations. Sum rules for higher moments of oscillator strengths are used for evaluating the corrections for the BBR-induced broadening and shift of Rydberg-state energy levels in neutral atoms and ions of arbitrary nuclear charge Z. [ABSTRACT FROM AUTHOR]

Simple analytical properties of ionization cross sections allow high-precision evaluations of contributions from integrals over continuum to sum rules for oscillator-strength moments and to the blackbody-radiation-induced shifts of atomic levels. The contributions from continuum and from infinite sums over discrete states are presented in terms of the cross section for the threshold photoionization. General properties of the indicated contributions are determined for bound states with small angular momenta (l ≼ 3) in hydrogen atoms. Asymptotic presentations for the contributions from continuum to the sums of oscillator-strength moments are proposed for highly excited Rydberg states. The estimate is given to the accuracy of determining the infinite sum over discrete states by a sum of a finite number of terms. [ABSTRACT FROM AUTHOR]

Rates of the blackbody radiation-induced excitation and decay were calculated for the S-, P-, D-series of the Rydberg states in sodium atoms with the Fues model potential method. Comparisons between three branches of the state depopulation mechanism (spontaneous decays, blakbody radiation-induced and excitations) were carried out. Simple analytical formulas were proposed for ratios of the blackbody radiation-induced decay and excitation rates to the spontaneous decay rate. [ABSTRACT FROM AUTHOR]

The rates of excitations and decays induced by blackbody radiation were calculated in the single-electron Fues' model potential approach for states up to n = 100 in rubidium s-, p- and d-series. On the basis of the calculations, general regularities for maxima rates of blackbody radiation induced decays and excitations were ascertained and a simple polynomial-based approximation formula was proposed for blackbody radiation induced decay and excitation rates of Rydberg states. A temperature parameterization for T = 50-1500 K was also proposed and respective matrices of coefficients were calculated. [ABSTRACT FROM AUTHOR]

A variety of approaches to determine the complete sequence of large DNA fragments is summarized. Main attention is paid to a transposon-based DNA sequencing strategy.

The primary structure of bacteriophage lambda DNA has been searched for the presence of consensus CAP binding sites. Four putative CAP binding sites have been found on the lambda genome, indicating that the catabolite gene activation system of E. coli may be directly involved in the regulation of lambda development. Molecular mechanisms of putative cAMP-CAP-mediated stimulation of lysogenic and lytic responses are discussed.

Cloning vèctor lambda gt-p MB9 has been used for cloning of DNA fragments of bacteriophage T5 produced by EcoR*I activity. One clone contains a DNA fragment of 2.2 Md which has been mapped at 67-71% on the physical map of the genome. Functional studies have shown that bacteriophage lambda gt-T5 can grow on E. coli lights 7. Infection of this E.coli strain with phage lambda gt-T5 induces DNA-ligase activity which has been previously observed in E. Coli infected with bacteriophage T5.

The expression of oLpLN region of the plasmid pNT6 causes the high instability of the plasmid. Mutations in the promoter pL region and lesions in the structural part of the N gene result in the stable inheritance of the plasmid. The plasmids pNT6::IS1 containing the IS1-element inserted into the different loci of oLpLN region restore the high instability of the plasmid inheritance in the strain 4830 coding for oLpLN. The plasmids pIG3 and pIG4 of the series pNT6: :IS1 permit one to obtain the collection of random deletions in the cloned fragments induced by IS1-element.

The plasmid pNT6 permits selection of IS1-element insertions into the plasmid occurring with the frequency about 10%. The bacteriophage promoter pL cloned in pNT6 is a hot-spot region for IS1-element insertion. The frequency of IS1 transposition into pL depends on genotype. The plasmid pNT6 may be considered to be a useful target DNA for screening and analysis of IS1-element transposition.