Nonlinear Lattices Generated from Harmonic Lattices with Geometric Constraints

Geometrical constraints imposed on higher dimensional harmonic lattices generally lead to nonlinear dynamical lattice models. Helical lattices obtained by such a procedure are shown to be described by sine- plus linear-lattice equations. The interplay between sinusoidal and quadratic potential terms in such models is shown to yield localized nonlinear modes identified as intrinsic resonant modes

On quantization of weakly nonlinear lattices. Envelope solitons

A way of quantizing weakly nonlinear lattices is proposed. It is based on introducing "pseudo-field" operators. In the new formalism quantum envelope solitons together with phonons are regarded as elementary quasi-particles making up boson gas. In the classical limit the excitations corresponding to frequencies above linear cut-off frequency are reduced to conventional envelope solitons. The approach allows one to identify the quantum soliton which is localized in space and understand existence of a narrow soliton frequency band.Comment: 5 pages. Phys. Rev. E (to appear

Homodyne locking of a squeezer

We report on the successful implementation of a new approach to locking the frequencies of an OPO-based squeezed-vacuum source and its driving laser. The technique allows the simultaneous measurement of the phase-shifts induced by a cavity, which may be used for the purposes of frequency-locking, as well as the simultaneous measurement of the sub-quantum-noise-limited (sub-QNL) phase quadrature output of the OPO. The homodyne locking technique is cheap, easy to implement and has the distinct advantage that subsequent homodyne measurements are automatically phase-locked. The homodyne locking technique is also unique in that it is a sub-QNL frequency discriminator.Comment: Accepted to Optics Letter

Energy thresholds for discrete breathers in one-, two- and three-dimensional lattices

Discrete breathers are time-periodic, spatially localized solutions of equations of motion for classical degrees of freedom interacting on a lattice. They come in one-parameter families. We report on studies of energy properties of breather families in one-, two- and three-dimensional lattices. We show that breather energies have a positive lower bound if the lattice dimension of a given nonlinear lattice is greater than or equal to a certain critical value. These findings could be important for the experimental detection of discrete breathers.Comment: 10 pages, LaTeX, 4 figures (ps), Physical Review Letters, in prin

Characterization of mutations induced by N-methyl-N '-nitro-N-nitrosoguanidine in an industrial Corynebacterium glutamicum strain

ArticleMUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS. 649(1-2): 239-244 (2008)journal articl

The Cgl1281-encoding putative transporter of the cation diffusion facilitator family is responsible for alkali-tolerance in Corynebacterium glutamicum

The original publication is available at www.springerlink.com.ArticleARCHIVES OF MICROBIOLOGY. 190(5): 531-538 (2008)journal articl

Risk Link to the Volcanic Activity of the Mt. Cameroon in Cameroon

The Mt. Cameroon is a large volcanic horst belonging to the majure tectonic line (Cameroon volcanic line). The geographical morphology of the mountain is controlled by regional tectonics. The Mt. Cameroon is consisted of precambrian metamorphic basement covered with Cretaceous to recent sediments distributed mainly in the Douala and Riodel Rey basin. The oldest lava could be of upper Miocene age. The Mt. Cameroon has erupted six times in the 20th century. The 1982 eruption took place inside the crater of an ancient cone. The lavas are picrites (with forsteritic olivine phenocrysts), alkali basalts (with salitic augite phenocrysts), hawaiites (with labrador-bytownite plagioclase phenocrysts) and mugearites (with scarce kaersutite phenocrysts and microlitic phlogopite or nosean). According to Deruelle et al.(1987), the Mt. Cameroon lava series is typically alkaline with no tholeiitic or transitional trend. Risk related to volcanism is actual for the human constructions especially along the axis of the horst. The severe volcanic risk has been limited to explosion, lava flows and lahar. It is possibility that explosion, laver flow and earthquarke take place anywhere on the volcanic mountain. Nevertheless, these explosions are most likely to occur in the delimited sector which is shown in a map presented in this paper. Even if we could divert the course of the lava flows to certain safer direction, flows caused by sudden earthquarke and explosion may cause serious damages