Localization fom conductance in few-channel disordered wires

We study localization in two- and three channel quasi-1D systems using multichain tight-binding Anderson models with nearest-neighbour interchain hopping. In the three chain case we discuss both the case of free- and that of periodic boundary conditions between the chains. The finite disordered wires are connected to ideal leads and the localization length is defined from the Landauer conductance in terms of the transmission coefficients matrix. The transmission- and reflection amplitudes in properly defined quantum channels are obtained from S-matrices constructed from transfer matrices in Bloch wave bases for the various quasi-1D systems. Our exact analytic expressions for localization lengths for weak disorder reduce to the Thouless expression for 1D systems in the limit of vanishing interchain hopping. For weak interchain hopping the localization length decreases with respect to the 1D value in all three cases. In the three-channel cases it increases with interchain hopping over restricted domains of large hopping

Current Helicity and Twist as Two Indicators of The Mirror Asymmetry of solar Magnetic Fields

A comparison between the two tracers of magnetic field mirror asymmetry in solar active regions, twist and current helicity, is presented. It is shown that for individual active regions these tracers do not possess visible similarity while averaging by time over the solar cycle, or by latitude, reveals similarities in their behaviour. The main property of the dataset is anti-symmetry over the solar equator. Considering the evolution of helical properties over the solar cycle we find signatures of a possible sign change at the beginning of the cycle, though more systematic observational data are required for a definite confirmation. We discuss the role of both tracers in the context of the solar dynamo theory.Comment: 14 pages, 6 figure

ВЛИЯНИЕ РЕНТГЕНОКОНТРАСТНОГО ВЕЩЕСТВА НА ФУНКЦИЮ ПОЧЕЧНОГО ТРАНСПЛАНТАТА ПРИ ЭНДОВАСКУЛЯРНОЙ РЕВАСКУЛЯРИЗАЦИИ МИОКАРДА

Ballon angioplasty with coronary arteries stenting was performed in 56 renal allograft recipients (75 procedures). The influence of contrast media on renal graft function was investigated. Renal graft function was estimated by creatinine level 24 hour before and 48 hours after the intervention. Risk factors of contrast induced nephropathy (CIN) development at renal graft recipients are discussed. Mathematical approaches for calculation of risk of CIN development are analyzed. Выполнена ангиопластика со стентированием коронарных артерий у 56 реципиентов почечного транс- плантата (75 процедур). В данной работе исследуется влияние рентгеноконтрастного вещества (РКВ) на функцию почечного трансплантата. Функция почечного трансплантата оценивалась по уровню креати- нина за 24 часа до и в первые 48 часов после вмешательства. Рассмотрено влияние и значимость факто- ров риска развития контрастинуцированной нефропатии (КИН) у реципиентов почечного трансплантата. Проанализированы математические подходы для расчета риска развития КИН.

Fokker-Planck description of the transfer matrix limiting distribution in the scattering approach to quantum transport

The scattering approach to quantum transport through a disordered quasi-one-dimensional conductor in the insulating regime is discussed in terms of its transfer matrix \bbox{T}. A model of $N$ one-dimensional wires which are coupled by random hopping matrix elements is compared with the transfer matrix model of Mello and Tomsovic. We derive and discuss the complete Fokker-Planck equation which describes the evolution of the probability distribution of \bbox{TT}^{\dagger} with system length in the insulating regime. It is demonstrated that the eigenvalues of \ln\bbox{TT}^{\dagger} have a multivariate Gaussian limiting probability distribution. The parameters of the distribution are expressed in terms of averages over the stationary distribution of the eigenvectors of \bbox{TT}^{\dagger}. We compare the general form of the limiting distribution with results of random matrix theory and the Dorokhov-Mello-Pereyra-Kumar equation.Comment: 25 pages, revtex, no figure

INFLUENCE OF CONTRAST MEDIA ON RENAL FUNCTION DURING ENDOVASCULAIRE MYOCARDIAL REVASCULARIZATION

Ballon angioplasty with coronary arteries stenting was performed in 56 renal allograft recipients (75 procedures). The influence of contrast media on renal graft function was investigated. Renal graft function was estimated by creatinine level 24 hour before and 48 hours after the intervention. Risk factors of contrast induced nephropathy (CIN) development at renal graft recipients are discussed. Mathematical approaches for calculation of risk of CIN development are analyzed