459 research outputs found
Electron-Electron scattering and resistivity of ballistic multimode channels
We show that electron--electron scattering gives a positive contribution to
the resistivity of ballistic multimode wires whose width is much smaller than
their length. This contribution is not exponentially small at low temperatures
and therefore may be experimentally observable. It scales with temperature as
for three-dimensional channels and as for two-dimensional ones.Comment: 4 pages, 3 figures; published versio
Regulation of Transfer of 137cs by Polymeric Sorbents for Grow Ecologically Sound Biomass
Soil contamination with radiocesium has a long-term radiological impact due to its long physical half-life (30.1 years for 137Cs and 2 years for 134Cs) and its high biological availability. 137Cs causes the largest concerns because of its deleterious effect on agriculture and stock farming, and, thus, human life for decades. One of the important aspects of the problem of contaminated soils remediation is understand of protective actions aimed at the reduction of biological migration of radionuclides in soil-plant system. The most effective way to bind radionuclides is the use of selective sorbents. The proposed research mainly aims to achieve control on transfer of 137Cs in a system growing mediaβplant due to counter ions variation in the polymeric sorbents. As the research object, Japanese basil-Perilla frutescens was chosen. Productivity of plants depending on the presence (control-without presence of polymer) and type of polymer material, as well as content of 137Cs in plant material has been determined. The character of different polymers influences on the 137Cs migration in growing mediaβplant system as well as accumulation in the plants has been cleared up
Population-genetic structure of the residents of Central Russia
In the territory of Central Russia, the presence of a certain, ordered system of grouping of elementary populations (raions) has been established, according to the data on the frequencies of surnames, using various methods of multivariate statistics (cluster analysis, multidimensional scaling, factor analysis). All the raions of the Belgorod oblast are combined into four clusters, corresponding to real geographical location of the populations: central cluster (12 raions), western (4 raions), south-eastern (3 raions), eastern (2 raions). Geographical distances between them play a significant role in the formation of genetic division between elementary population
Structure formation in the heat treatment of relatively reliable 13XΦA steel oil pipe
Aromaticity in a Surface Deposited Cluster: Pd on TiO (110)
We report the presence of \sigma-aromaticity in a surface deposited cluster,
Pd on TiO (110). In the gas phase, Pd adopts a tetrahedral
structure. However, surface binding promotes a flat, \sigma-aromatic cluster.
This is the first time aromaticity is found in surface deposited clusters.
Systems of this type emerge as a promising class of catalyst, and so
realization of aromaticity in them may help to rationalize their reactivity and
catalytic properties, as a function of cluster size and composition.Comment: 4 pages, 3 figure
Genetic and demographic characteristics of population of Central Russia
The paper presents data on the assessment of the size of elementary population among the residents of Central Russia. It has been defined that population-genetic study of the residents of Central Russia should be carried out at the level of raion, which is an elementary population. The size of elementary population should be taken into account when forming the samples for further genetic and epidemiological surveys of populatio
Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XV. Long-Term Optical Monitoring of NGC 5548
We present the results of three years of ground-based observations of the
Seyfert 1 galaxy NGC 5548, which combined with previously reported data, yield
optical continuum and broad-line H-beta light curves for a total of eight
years. The light curves consist of over 800 points, with a typical spacing of a
few days between observations. During this eight-year period, the nuclear
continuum has varied by more than a factor of seven, and the H-beta emission
line has varied by a factor of nearly six. The H-beta emission line responds to
continuum variations with a time delay or lag of 10-20 days, the precise value
varying somewhat from year to year. We find some indications that the lag
varies with continuum flux in the sense that the lag is larger when the source
is brighter.Comment: 29 pages, 6 figures. Accepted for publication in ApJ (1999 Jan 10
Predicting relapse in demyelinating diseases in children
Introduction. Predicting relapse in acute demyelinating episode (ADE) in children is an urgent problem, since progressive demyelinating diseases are associated with the risk of disability and cognitive impairment.ΠΠ²Π΅Π΄Π΅Π½ΠΈΠ΅. ΠΡΠΎΠ³Π½ΠΎΠ·ΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠ΅ΡΠΈΠ΄ΠΈΠ²Π° ΠΏΡΠΈ ΠΎΡΡΡΠΎΠΌ Π΄Π΅ΠΌΠΈΠ΅Π»ΠΈΠ½ΠΈΠ·ΠΈΡΡΡΡΠ΅ΠΌ ΡΠΏΠΈΠ·ΠΎΠ΄Π΅ (ΠΠΠ) Ρ Π΄Π΅ΡΠ΅ΠΉ ΡΠ²Π»ΡΠ΅ΡΡΡ Π°ΠΊΡΡΠ°Π»ΡΠ½ΠΎΠΉ ΠΏΡΠΎΠ±Π»Π΅ΠΌΠΎΠΉ, ΠΏΠΎΡΠΊΠΎΠ»ΡΠΊΡ ΠΏΡΠΎΠ³ΡΠ΅ΡΡΠΈΡΡΡΡΠΈΠ΅ Π΄Π΅ΠΌΠΈΠ΅Π»ΠΈΠ½ΠΈΠ·ΠΈΡΡΡΡΠΈΠ΅ Π·Π°Π±ΠΎΠ»Π΅Π²Π°Π½ΠΈΡ Π°ΡΡΠΎΡΠΈΠΈΡΠΎΠ²Π°Π½Ρ Ρ ΡΠΈΡΠΊΠΎΠΌ ΠΈΠ½Π²Π°Π»ΠΈΠ΄Π½ΠΎΡΡΠΈ ΠΈ ΠΊΠΎΠ³Π½ΠΈΡΠΈΠ²Π½ΡΡ
Π½Π°ΡΡΡΠ΅Π½ΠΈ
Steps Toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A Thirteen-Year Study of Spectral Variability in NGC 5548
We present the final installment of an intensive 13-year study of variations
of the optical continuum and broad H-beta emission line in the Seyfert 1 galaxy
NGC 5548. The data base consists of 1530 optical continuum measurements and
1248 H-beta measurements. The H-beta variations follow the continuum variations
closely, with a typical time delay of about 20 days. However, a year-by-year
analysis shows that the magnitude of emission-line time delay is correlated
with the mean continuum flux. We argue that the data are consistent with the
simple model prediction that the size of the broad-line region is proportional
to the square root of the ionizing luminosity. Moreover, the apparently linear
nature of the correlation between the H-beta response time and the nonstellar
optical continuum arises as a consequence of the changing shape of the
continuum as it varies, specifically with the optical (5100 A) continuum
luminosity proportional to the ultraviolet (1350 A) continuum luminosity to the
0.56 power.Comment: 20 pages plus 4 figures. Accepted for publication in The
Astrophysical Journa
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