Complex criteria for ecological assessment of the efficiency of intra-water-body processes

Modern ecological control methods of the state of hydro-ecosystems of river basins have been developed for ensuring their sustainable development, assessment of self-recovery properties of aquatic ecosystems that are a reflection of intra-water-body processes. For the first time ever the index of hydro-ecosystem development was proposed for conducting the ecological control of such systems.     

Enhanced and stimulated multiphoton processes in free atoms

An enhanced two-photon emission has been observed between the 6S and the 4S levels of potassium. The priming field is the stimulated electronic Raman emission at 2720 cm^-1due to scattering of ruby laser radiation from the4P_{3/2}state in potassium. The intense emission at the complementary frequency ω2is close to the 5P → 4S resonance lines. As a result, the coupling coefficient has a resonance character that is favorable for the enhancement. The observed results are compared with a simple analysis. The relation of the enhanced emission with two-quantum absorption, stimulated Raman effect, and parametric four-photon processes is discussed.     

Preemptive scheduling on uniformly related machines: minimizing the sum of the largest pair of job completion times

We revisit the classic problem of preemptive scheduling on m uniformly related machines. In this problem, jobs can be arbitrarily split into parts, under the constraint that every job is processed completely, and that the parts of a job are not assigned to run in parallel on different machines. We study a new objective which is motivated by fairness, where the goal is to minimize the sum of the two maximal job completion times. We design a polynomial time algorithm for computing an optimal solution. The algorithm can act on any set of machine speeds and any set of input jobs. The algorithm has several cases, many of which are very different from algorithms for makespan minimization (algorithms that minimize the maximum completion time of any job), and from algorithms that minimize the total completion time of all jobs.     

Analysis of stimulated Raman scattering in waveguides

Stokes radiation, excited by a giant pulse radiation propagating along a rectangular wavegulde, is analyzed in this paper. Equations are established and solved for an arbitrary shape of the giant pulse. At high gains the stimulated radiation is emitted at all angles. The maximum output is almost perpendicular to the exciting beam, and it decreases as the forward and backward directions are approached. Forward-backward ratios are sensitive to the detailed shape and magnitude of the laser pulse. The large forward-backward ratio for intense short laser pulses accounts for the observed results, which are illustrated for a square and a parabolic pulse. In practice, a large number of waveguide modes are simultaneously excited, resulting in intense excitation of vibrational modes in the medium, and enhancement of the inverse Raman effect and of anti-Stokes generation.     

Induced versus parametric scattering processes in potassium

Stimulated and enhanced two-photon emissions from excited states in potassium have been observed. This emission is primed by stimulated electronic Raman radiation generated by scattering of a giant pulse ruby radiation. Four-photon parametric processes also take place. The two processes can be distinguished by tuning the laser frequency. Most of the emitted radiations are plane-polarized. A pumping model is proposed explaining the required population inversions and the polarization properties of the radiations.