RESULTS OF EXPERIMENTAL RESEARCH AND SIMULATION OF MULTI-CORE FIBER WAVEGUIDE WITH FIBER BRAGG GRATINGS ARRAY

Subject of Research. The development and creation of a measurement system for determination and monitoring of the location and bends of extended objects in space are actual at the moment.We propose the creation of a sensitive part of fiber-optic measurement system based on chirped fiber Bragg gratings (FBGs) inscribed in a multi-core fiber. Method. The method essencelies independence determination of the grating period change in each core on the bending radius of the fiber, that gives the possibility to reconstruct remotely the trajectory of the optical fiber laying in space.Main Results. The paper presents experiment results with a single-mode fiber with an array of chirped FBGs. The experimental optical scheme and the reflection spectra before and after the single-core optical fiber bending are shown. The geometry and computer model of multi-core fiber section with a given radius bend are described. Practical Relevance. Unlike the other existing fiber-optic measurement systems, a system with multi-core optical fiber with chirped FBGs array makes it possible to determine the trajectory of fiber-optic light guide laying in space without using methods of optical frequency domain reflectometry, which determine the location of the Bragg gratings along the optical fiber length

Indices of dental health in children and adolescents from Saratov and the Saratov region

<p>Objective: to determine the level of dental health in children and adolescents living in the Saratov region. Material and methods. To assess the intensity and prevalence of major dental diseases 1510 patients have been examined by the method recommended by the WHO Collaborating Centre in Russia. Results. A comparative analysis of caries and occurrence of different types of teeth-maxillary anomalies among children aged from 3 to 18 years. Conclusion. The epidemiology of major dental diseases in the Saratov region is characterized by the significant spread of caries from 70 to 94,6% in the different age groups. The proportion of people with malocclusion among the surveyed reaches 46,6%.</p

BIOSOCIAL FACTORS AND PSYCHOVEGETATIVE PECULIARITIES IN FORMATION OF ADAPTATION ABNORMALITIES IN CHILDREN WITH GROWTH RETARDATION

110 children aged 7-16 with growth retardation have been under the study. Children with different clinical variants of growth retardation are characterized by individual clinical psychophysiological peculiarities. The cause-effect relation of biosocial factors, psychovegetative changes and high morbidity rate of children with growth retardation established in the research point out to their adaptation abnormalities, that require a differentiated approach to the development of rehabilitation programs

Isovector soft dipole mode in 6Be

By using the 1H(6Li,6Be)n charge-exchange reaction, continuum states in 6Be were populated up to E_t=16 MeV, E_t being the 6Be energy above its three-body decay threshold. In kinematically complete measurements performed by detecting alpha+p+p coincidences, an E_t spectrum of high statistics was obtained, containing approximately ~5x10^6 events. The spectrum provides detailed correlation information about the well-known 0^+ ground state of 6Be at E_t=1.37 MeV and its 2^+ state at E_t=3.05 MeV. Moreover, a broad structure extending from 4 to 16 MeV was observed. It contains negative parity states populated by Delta L=1 angular momentum transfer without other significant contributions. This structure can be interpreted as a novel phenomenon, i.e. the isovector soft dipole mode associated with the 6Li ground state. The population of this mode in the charge-exchange reaction is a dominant phenomenon for this reaction, being responsible for about 60% of the cross section obtained in the measured energy range.Comment: 8 pages, 7 figure

The spectrum features of UHECRs below and surrounding GZK

The energy spectrum of UHECRs is discussed on the basis of the Yakutsk array database analysis. In the region E=0.1 to 30 EeV the showers are detected under trigger-500, while at energies above 30 EeV the whole acceptance area for trigger-1000 is used in order to utilize all the data available in the region of GZK cutoff.Comment: Invited talk at CRIS2004: GZK and surroundings, Catania, Italy, 31.05.04. To appear in Nucl. Phys. B Proc. Supp

Nucleosomes in gene regulation: theoretical approaches

This work reviews current theoretical approaches of biophysics and bioinformatics for the description of nucleosome arrangements in chromatin and transcription factor binding to nucleosomal organized DNA. The role of nucleosomes in gene regulation is discussed from molecular-mechanistic and biological point of view. In addition to classical problems of this field, actual questions of epigenetic regulation are discussed. The authors selected for discussion what seem to be the most interesting concepts and hypotheses. Mathematical approaches are described in a simplified language to attract attention to the most important directions of this field

Energetic particle influence on the Earth's atmosphere

This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere