Mach-Zehnder interferometer in the fractional quantum Hall regime.

We consider tunneling between two edges of quantum Hall liquids of filling factors nu(0,1)=1/(2m(0,1)+1), with m(0)>or=m(1)>or=0, through two-point contacts forming a Mach-Zehnder interferometer. A quasiparticle description of the interferometer is derived explicitly through the instanton duality transformation. For m(0)+m(1)+1 identical withm>1, tunneling of quasiparticles of charge e/m leads to nontrivial m-state dynamics of effective flux through the interferometer, which restores the regular "electron" periodicity of the current in flux.

[Phylogeny of the Malus (apple tree) species, inferred from its morphological traits and molecular DNA analysis].

Some debated issues of the genus Malus (apple) taxonomy were examined using a variety of species from the collection of the Maikop Experimental Station, Vavilon Research Institute of Plant Industry (Krasnodar krai). Phylogenetic relationships among these species were studied using traditional analysis of morphological traits, RAPD, and complete sequencing of the 5'-internal transcribed spacer (ITS1), 5.8S rRNA, 3'-internal transcribed spacer (ITS2) (constituting a cluster of the rRNA genes), and the terminal fragment of the matK gene encoding chloroplast maturase.

Plasticity of social behavior in Drosophila.

This article presents results obtained from studies of the plasticity of changes in social behavior in Drosophila (interactions between individuals in groups) in conditions of homo- and heterogeneous environments. This is the first report of data illustrating self-starting acquisition by female Drosophila of a classical conditioned reflex to contextual factors signaling possible threats from other individuals and blocking the initiation of activity. A previously described operant conditioned reflex also helped flies avoid aggression from other individuals and make more efficient use of food resources by decreasing the initially high level of activity.

[Plasticity of the social behavior in Drosophila].

Original data illustrate self-starting classical conditioning to environmental factors in Drosophila, the factors serving as signals of a possible threat from other individuals and blocking initiation of activity. Instrumental conditioning resulting in reduction of an initially high level of activity in the group situation, helps a fly to avoid aggression from other flies and to use the food resources more efficiently. Classical conditioning makes it unnecessary for a fly to learn this instrumental task again and again: being faced with an analogous situation the fly automatically decreases its activity following presentation of the conditioned stimuli or the specific environment.

Coulomb drag between one-dimensional conductors.

We have analyzed Coulomb drag between currents of interacting electrons in two parallel one-dimensional conductors of finite length L attached to external reservoirs. For strong coupling, the relative fluctuations of electron density in the conductors acquire energy gap M. At energies larger than gamma = constxv(-)exp(-LM/v(-))/L+gamma(+), where gamma(+) is the impurity scattering rate, and, for L>v(-)/M, where v(-) is the fluctuation velocity, the gap leads to an "ideal" drag with almost equal currents in the conductors.

Zero-point fluctuations and the quenching of the persistent current in normal metal rings.

The ground state of a phase-coherent mesoscopic system is sensitive to its environment. We investigate the persistent current of a ring with a quantum dot which is capacitively coupled to an external circuit with a dissipative impedance. At zero temperature, zero-point quantum fluctuations lead to a strong suppression of the persistent current with decreasing external impedance.

Genetic aspects of the mechanisms of learning.

Published data demonstrating the direct involvement of the genome in processes associated with learning are presented. These processes include the intensification of protein and RNA synthesis during learning and induction of early gene expression during learning. The relationship between consolidation of memory traces and protein synthesis is discussed.

[Genetic aspects of learning mechanisms].

The following literature data point to the direct involvement of genome into processes related to learning; the protein and RNA synthesis intensification and the induction of the immediate-early genes expression in the course of learning, dependence of the memory consolidation upon the protein synthesis. In addition to the memory forms requiring induction of the gene expression for consolidation, there are forms of the long-lasting memory independent on the protein synthesis. The usage of genetic techniques in studying the mechanisms of learning and memory is considered.

[The characteristics of the circadian motor activity of sturgeons and their hybrids studied by a motion picture-TV method].

Technique of slow-motion shot was used for simultaneous automatic recording of behaviour of sturgeon species Acipenser nudiventris and its hybrid with white sturgeon, Huso huso. The hybrids and the individuals of the paternal species were placed in two separate aquaria under the conditions of constant light. Cinematographic recording was performed each hour throughout 3 days during 30 s per hour.

[The characteristics of the antigenic and cytotropic properties of free subunits of the C-reactive protein].

A simple method of preparation of functionally active subunits of C-reactive protein (CRP) is described. Antigenic and biological properties of CRP and its subunits were compared. CRP subunits are shown to differ from the native CRP molecule by antigenicity and mitogenicity.

The influence of serotonin and p-chlorophenylalanine on locomotor activity of Drosophila melanogaster.

Two hours after injection of serotonin into 3-day-old virgin females of Drosophila melanogaster, a significant dose-dependent increase in locomotor activity was observed. Since this stimulating effect can be produced either by serotonin or by some of its derivatives that might have formed during these two hours, the fate of injected [3H]-serotonin in the organism of Drosophila was traced by means of thin layer chromatography. The only metabolite found appeared to be N-acetylserotonin.

[Effect of mutant genes with a known biochemical effect on the rate of conditioned motor reflex formation in honey bees].

The influence of inherited disturbance of metabolic transformations of aromatic aminoacid tryptophan on the speed of learning in T-shaped maze was studied in two groups of bees, homo- and heterozygote by chartreuse-red mutation. It was shown that in homozygote individuals, as compared to heterozygotes, the speed of learning in response to visual and tactile stimuli, is 3 times lower. It is suggested that the depressive effect of chartreuse-red mutation on learning is not limited to visual sensory deficiency but may be due to a biochemical shift in tryptophan metabolism, important for the activity of the nervous system.

[Some specific features of enzymatic dehydration of tetrahydro-1,4-benzdiazepine-2-one].

Differences in the dehydration rates of tetrahydro-1,4-benzdiazepine-2-one in the liver, kidney and adrenals of mice, rats and guinea pigs have been revealed. It has been found that the enzyme catalyzing the substrate conversion into its dihydroderivative is localized in the microsomal and soluble fractions of the organs tested and has a pH optimum of 9,0. The enzyme activity depends on the concentation of phosphate ions in the incubation medium.