Impurity pinning in transport through 1D Mott-Hubbard and spin gap insulators

A low energy crossover (see cond-mat/9711167) induced by Fermi liquid reservoirs in transport through a 1D Mott-Hubbard insulator of finite length $L$ is examined in the presence of impurity pinning. Under the assumption that the Hubbard gap 2M is large enough: $M > T_L \equiv v_c/L$ ($v_c$: charge velocity in the wire) and the impurity backscattering rate $\Gamma_1 \ll T_L$, the conductance vs. voltage/temperature displays a zero-energy resonance. Transport through a spin gapped 1D system is also described availing of duality between the backscattered current of this system and the direct current of the Mott-Hubbard insulator.Comment: 5 twocolumn pages in RevTex, no figure

Quantum critical behaviour of the plateau-insulator transition in the quantum Hall regime

High-field magnetotransport experiments provide an excellent tool to investigate the plateau-insulator phase transition in the integral quantum Hall effect. Here we review recent low-temperature high-field magnetotransport studies carried out on several InGaAs/InP heterostructures and an InGaAs/GaAs quantum well. We find that the longitudinal resistivity $\rho_{xx}$ near the critical filling factor $\nu_{c}$ ~ 0.5 follows the universal scaling law $\rho_{xx}(\nu, T) \propto exp[-\Delta \nu/(T/T_{0})^{\kappa}]$, where $\Delta \nu =\nu -\nu_{c}$. The critical exponent $\kappa$ equals $0.56 \pm 0.02$, which indicates that the plateau-insulator transition falls in a non-Fermi liquid universality class.Comment: 8 pages, accepted for publication in Proceedings of the Yamada Conference LX on Research in High Magnetic Fields (August 16-19, 2006, Sendai

Transport properties of single channel quantum wires with an impurity: Influence of finite length and temperature on average current and noise

The inhomogeneous Tomonaga Luttinger liquid model describing an interacting quantum wire adiabatically coupled to non-interacting leads is analyzed in the presence of a weak impurity within the wire. Due to strong electronic correlations in the wire, the effects of impurity backscattering, finite bias, finite temperature, and finite length lead to characteristic non-monotonic parameter dependencies of the average current. We discuss oscillations of the non-linear current voltage characteristics that arise due to reflections of plasmon modes at the impurity and quasi Andreev reflections at the contacts, and show how these oscillations are washed out by decoherence at finite temperature. Furthermore, the finite frequency current noise is investigated in detail. We find that the effective charge extracted in the shot noise regime in the weak backscattering limit decisively depends on the noise frequency $\omega$ relative to $v_F/gL$, where $v_F$ is the Fermi velocity, $g$ the Tomonaga Luttinger interaction parameter, and $L$ the length of the wire. The interplay of finite bias, finite temperature, and finite length yields rich structure in the noise spectrum which crucially depends on the electron-electron interaction. In particular, the excess noise, defined as the change of the noise due to the applied voltage, can become negative and is non-vanishing even for noise frequencies larger than the applied voltage, which are signatures of correlation effects.Comment: 28 pages, 19 figures, published version with minor change

Fractional charge in transport through a 1D correlated insulator of finite length

Transport through a one channel wire of length $L$ confined between two leads is examined when the 1D electron system has an energy gap $2M$: $M > T_L \equiv v_c/L$ induced by the interaction in charge mode ($v_c$: charge velocity in the wire). In spinless case the transformation of the leads electrons into the charge density wave solitons of fractional charge $q$ entails a non-trivial low energy crossover from the Fermi liquid behavior below the crossover energy $T_x \propto \sqrt{T_L M} e^{-M /[T_L(1-q^2)]}$ to the insulator one with the fractional charge in current vs. voltage, conductance vs. temperature, and in shot noise. Similar behavior is predicted for the Mott insulator of filling factor $\nu = integer/(2 m')$.Comment: 5 twocolumn pages in RevTex, no figure

Threshold features in transport through a 1D constriction

Suppression of electron current $\Delta I$ through a 1D channel of length $L$ connecting two Fermi liquid reservoirs is studied taking into account the Umklapp electron-electron interaction induced by a periodic potential. This interaction causes Hubbard gaps $E_H$ for $L \to \infty$. In the perturbative regime where $E_H \ll v_c/L$ ($v_c:$ charge velocity), and for small deviations $\delta n$ of the electron density from its commensurate values $- \Delta I/V$ can diverge with some exponent as voltage or temperature $V,T$ decreases above $E_c=max(v_c/L,v_c \delta n)$, while it goes to zero below $E_c$. This results in a nonmonotonous behavior of the conductance.Comment: Final variant published in PRL, 79, 1714; minor correction

State of infantile mortality in Chernigov area.

State and dynamics of perinatal and infant mortality rate in Chernigov region over the 2001-2010 period were studied. It is shown that the level of perinatal mortality and mortinatality should be analysed separately over 2 periods: 2001-2006 and 2007-2010, as in 2007 Ukraine turned to determination of perinatal period, live birth - and mortinatality according to WHO criteria. It is identified that over the 2001-2006 period there were no considerable changes of perinatal mortality level in Chernigov region. Over the 2007-2010 period this index dropped by 14 %, while in Ukraine – only by 6,3 %. During 2001-2006 mortinatality in this area was lower than in Ukraine, however it had a tendency to increase (by 10,6%); in subsequent years this resulted in exceeding of national values. Level of mortinatality rate in Chernigov region over the 2001-2010 period dropped by 28,6%, while in Ukraine – by 19,5%. It is identified that decrease in level of mortinatality occurred due to the decline of both neonatal and postneonatal mortality rate. Ranking of region areas by the levels of perinatal mortality, mortinatality, infant mortality, including neonatal and postneonatal mortality was conducted. It is found that perinatal states, inborn anomalies and accidents are the main causes of infant mortality both in Chernigov region and in Ukraine as a whole. Over the 2004-2010 period proportion of perinatal states in the structure of infant mortality rate increased by 14,8 %

ВИКОРИСТАННЯ ФАРМАКОКІНЕТИЧНИХ ПАРАМЕТРІВ З МЕТОЮ ПЛАНУВАННЯ РЕЖИМІВ ДОЗУВАННЯ ДЛЯ ЛІКАРСЬКИХ ПЛІВОК ПІД УМОВНОЮ НАЗВОЮ МЕТРО-ПЛІВКА

The developed method of "compression" of data of farmakokichnikh researches is with the use of odnokamernoy model. Farmakokichni researches of medical tapes which contain metronidazol are conducted. A high-quality evaluation is additionally conducted them farmakokichnikh paramtters with establishment of the optimum individual modes of dosage.Разработана методика «сжатия» данных фармакокинетических исследований с использованием однокамерной модели. Проведены фармакокинетические исследования лекарственных пленок, содержащих метронидазол. Дополнительно проведена качественная оценка их фармакокинетических параметров с установлением оптимальных индивидуальных режимов дозирования.Розроблена методика «стиснення» даних фармакокінетичних  досліджень з використанням однокамерної моделі. Проведені фармакокінетичні дослідження лікарських плівок, що містять метронідазол. Додатково проведено якісне оцінювання їх фармакокінетичних параметрів із встановленням оптимальних індивідуальних режимів дозування

ФОРМУВАННЯ У СТУДЕНТІВ МЕДИЧНОГО КОЛЕДЖУ ЦІННІСНОГО СТАВЛЕННЯ ДО ВЛАСНОГО ЗДОРОВ’Я ЯК ОСНОВНА СКЛАДОВА ПІДГОТОВКИ ДО САНІТАРНО-ГІГІЄНІЧНОГО ВИХОВАННЯ ТА ПРОВЕДЕННЯ ПРОФІЛАКТИЧНОЇ РОБОТИ В СВОЇЙ МАЙБУТНІЙ ПРОФЕСІЙНІЙ ДІЯЛЬНОСТІ

The article deals with the problem of maintaining and formation of value attitude to the health in students of medical college as the main component of preparation for hygienic upbringing and conducting preventive work in their future careers.У статті розглянуто проблеми збереження та формування ціннісного ставлення до власного здоров’я у студентів медичного коледжу як основної складової підготовки до санітарно-гігієнічного виховання та проведення профілактичної роботи в своїй майбутній професійній діяльності