Nuclei-induced frequency focusing of electron spin coherence

The hyperfine interaction of an electron with the nuclei is considered as the primary obstacle to coherent control of the electron spin in semiconductor quantum dots. We show, however, that the nuclei in singly charged quantum dots act constructively by focusing the electron spin precession about a magnetic field into well-defined modes synchronized with a laser pulse protocol. In a dot with a synchronized electron, the light-stimulated fluctuations of the hyperfine nuclear field acting on the electron are suppressed. The information about electron spin precession is imprinted in the nuclei and thereby can be stored for tens of minutes in darkness. The frequency focusing drives an electron spin ensemble into dephasing-free subspaces with the potential to realize single frequency precession of the entire ensemble.     

Effect of yeast extract on intestinal development and productivity of broilers

During raising of chicks, mixed feed was used animal- and plant-origin feeds and also supplementing it with 2% yeast extract NuPro, which allowed improving intestinal morphology and increasing the rate of its development and poultry productivity.     

Soil-agrochemical aspects of remediation of a gray forest soil polluted with Pb upon the application of growth-promoting rhizobacteria

The effect of inoculation with growth-promoting rhizobacteria of the Pseudomonas genus on the growth and elemental composition of barley was examined in pot experiments with an artificially Pb-contaminated gray forest soil. The application of the bacteria to the contaminated soil enhanced the plant growth, increased the yield (including the grain yield) by 1.5 times, and considerably reduced the concentration of Pb in the plants without altering the soil reaction. The maximum effect was found upon the inoculation with the bacterium P. fluorescens 21, which ensures the same yield as that in the unpolluted soil without the application of bacteria and without changes in the grain quality (the protein content and the elemental composition). The positive effect of the bacteria was manifested to the greatest degree at the beginning and in the first half of the growing period and was associated with considerable binding of Pb in the soil compounds extractable with an ammonium acetate buffer solution. The elimination of the toxic effect and weakening of the Pb translocation in the barley plants after the inoculation with bacteria occurred due to the improvement in the mineral nutrition of the plants, the intensification of their barrier functions at the shoot-root and root-soil interfaces, the biological dilution caused by an increase in the plant biomass, and changes in the bioavailability of the metal (probably, under the influence of exometabolites produced by bacteria). The application of bacteria did not affect the removal of Pb from the soil by the plants (the biological remediation of the soil via phytoextraction of the toxicants).     

Influence of Rhizosphere Bacteria on the State of Heavy Metal Сompounds in the Soil–Plant System

Eurasian Soil Science - The results of a greenhouse experiment with the humus horizon of a sandy loamy soddy-podzolic soil are presented. It was contaminated with heavy metals added with sewage...     

Grain yield and quality of winter wheat inoculated with a mixed culture of <Emphasis Type="Italic">Pseudomonas</Emphasis> bacteria against the background of increasing nitrogen fertilizer rates

The effect of a mixed culture of non-nitrogen fixing bacterium Pseudomonas fluorescens 20 and nitrogen-fixing bacterium Pseudomonas putida 23 on winter wheat grain yield, nitrogen removal by plants, and content of protein and ash elements in grain against a background of nitrogen fertilizer was studied in a microplot experiment on gray forest soil.     

Mode locking of electron spin coherences in singly charged quantum dots

The fast dephasing of electron spins in an ensemble of quantum dots is detrimental for applications in quantum information processing. We show here that dephasing can be overcome by using a periodic train of light pulses to synchronize the phases of the precessing spins, and we demonstrate this effect in an ensemble of singly charged (In,Ga)As/GaAs quantum dots. This mode locking leads to constructive interference of contributions to Faraday rotation and presents potential applications based on robust quantum coherence within an ensemble of dots.     

Adaptive landscape modernization of forest and hydraulic ameliorative land management in the Volga region

An analysis of adaptive landscape amelioration of lands with a geomorphologic classification of characteristic types of agrolandscapes is given. Control of drought and soil-destroying processes is based on a systems approach, including organizational-economic and agro-, phyto-, forest, and hydraulic amelioration measures. The system of ameliorative procedures takes into account the ecological ameliorative requirements and limitations with the developed criteria and standardized evaluation parameters of soils and waters when realizing the concept of adaptive landscape management.     

The effect of Azospirillum brasilense Sp7 and Azotobacter chroococcum on nitrogen balance in soil under cropping with oats (Avena sativa L.)

Summary Pot experiments with oats were carried out to study the effect of Azospirillum brasilense Sp 7 and Azotobacter chroococcum 94K on the yield of plants, the N content of soil and the ¹⁴N balance. The plants were grown on gray forest soil under irrigation with deionized water and application of ¹⁵N-labelled fertilizer at a rate of 4 mg N 100 g^-1 soil. Inoculation of plants with Azospirillum spp. and Azotobacter spp. failed to increase the plant yield. However, the increase in total N in the soil at the end of the experiment and the positive ¹⁴N balance in the soil-plant system due to increased nitrogenase activity in the rhizosphere were statistically significant. The amount of N accumulated in the soil was comparable with the rate of N applied as fertilizer.     

Agroecological characteristics of winter wheat growing technologies in Volga agrolandscapes

Agroecological and economic indices of energy-conservation winter wheat growing technologies in the Volga agrolandscapes with the use of various soil conservation tillage methods are given.