Transversity Distribution and Polarized Fragmentation Function from Semi-inclusive Pion Electroproduction

A method is discussed to determine the hitherto unknown u-quark transversity distribution from a planned HERMES measurement of a single-spin asymmetry in semi-inclusive pion electroproduction off a transversely polarized target. Assuming u-quark dominance, the measurement yields the shapes of the transversity distribution and of the ratio of a polarized and the unpolarized u-quark fragmentation functions. The unknown relative normalization can be obtained by identifying the transversity distribution with the well-known helicity distribution at large x. The systematic uncertainty of the method is dominated by the assumption of u-quark dominance.Comment: 5 pages, 5 figures, revised version as will be published in EPJ

Resonant tunneling through a macroscopic charge state in a superconducting SET transistor

We predict theoretically and observe in experiment that the differential conductance of a superconducting SET transistor exhibits a peak which is a complete analogue in a macroscopic system of a standard resonant tunneling peak associated with tunneling through a single quantum state. In particular, in a symmetric transistor, the peak height is universal and equal to $e^2/2\pi \hbar$. Away from the resonance we clearly observe the co-tunneling current which in contrast to the normal-metal transistor varies linearly with the bias voltage.Comment: 11 pages, 3 figures, Fig. 1 available upon request from the first autho

Coupling functions for lead and lead-free neutron monitors from the latitudinal measurements performed in 1982 in the research station Academician Kurchatov

The latitudinal behavior of intensities and multiplicities was registered by the neutron monitor 2 NM and the lead-free neutron monitor 3 SND (slow-neuron detector) in the equator-Kaliningrad line in the Atlantic Ocean. Coupling coefficients for 3 SND show the sensitivity of this detector to primary particles of cosmic rays of energies on the average lower than for 2 NM. As multiplicities increase, the coupling coefficients shift towards higher energies

Sensitivity of single and multiple cosmic ray neutrons to the surrounding medium in a lead-free monitor

In 1981-1985 the neutron component of cosmic rays was recorded, the effect of cosmic ray multiplication in lead being disregarded. The recording device consisted of neutron counters placed in a polyethylene retarder (polyethylene tubes with wall thickness of 2 cm). The device registered neutrons formed directly on the surface or not deep underground; the intensity of neutrons depended on the chemical composition of the substance. The neutron component was also measured in the Moscow Canal, Belomor-Baltic Canal, and in the Atlantic Ocean. The time variation of 5 minute data of the intensity obtained in the Belomor-Baltic Canal and in the Atlantic Ocean relative to the mean value in the open sea (in %) is presented

Nonequilibrium spin distribution in single-electron transistor

Single-electron transistor with ferromagnetic outer electrodes and nonmagnetic island is studied theoretically. Nonequilibrium electron spin distribution in the island is caused by tunneling current. The dependencies of the magnetoresistance ratio $\delta$ on the bias and gate voltages show the dips which are directly related to the induced separation of Fermi levels for electrons with different spins. Inside a dip $\delta$ can become negative.Comment: 11 pages, 2 eps figure

Reversed Switch-On Dynistor Switches of Gigawatt Power Microsecond Pulses

A high-power (250 kA and 25 kV) compact switch based on an assembly of reversed switch-on dynistors (RSDs) connected in series and a coaxial saturable-core choke, which is necessary for their effective switching, is described. An essential feature of this switch is a drastic reduction of the duration of RSDs control pulse, which allows using minimum dimensions and low inductance saturable core choke and obtain high rise rate (more than 30 kA/µs) of the switched current. The increased RSDs control pulse amplitude and rise rate that are required for RSDs switching on by reduced duration triggering pulse are attained by using a fast switch based on new type semiconductor devices deep-level dynistors (DLDs)

Legal protection of life and health of a child: interbranch problems

The current study considered the problems of legal protection of a child’s life and health before and after birth, analyzed Russian and foreign legislation, it was proposed to consolidate the fundamental principles of international law in the legislation of Russian Federation, and it was provided the human embryo protectio

Radio-frequency Bloch-transistor electrometer

A quantum-limited electrometer based on charge modulation of the Josephson supercurrent in the Bloch transistor inserted into a superconducting ring is proposed. As this ring is inductive coupled to a high-Q resonance tank circuit, the variations of the charge on the transistor island (input signal) are converted into variations of amplitude and phase of radio-frequency oscillations in the tank. These variations are amplified and then detected. The output noise, the back-action fluctuations and their cross-correlation are computed. It is shown that our device enables measurements of the charge with a sensitivity which is determined by the energy resolution of its amplifier, that can be reduced down to the standard quantum limit of \hbar/2. On the basis of this setup a "back-action-evading" scheme of the charge measurements is proposed.Comment: 5 pages incl. 2 figure

A Numerical Study of Transport and Shot Noise at 2D Hopping

We have used modern supercomputer facilities to carry out extensive Monte Carlo simulations of 2D hopping (at negligible Coulomb interaction) in conductors with the completely random distribution of localized sites in both space and energy, within a broad range of the applied electric field $E$ and temperature $T$, both within and beyond the variable-range hopping region. The calculated properties include not only dc current and statistics of localized site occupation and hop lengths, but also the current fluctuation spectrum. Within the calculation accuracy, the model does not exhibit $1/f$ noise, so that the low-frequency noise at low temperatures may be characterized by the Fano factor $F$. For sufficiently large samples, $F$ scales with conductor length $L$ as $(L_c/L)^{\alpha}$, where $\alpha=0.76\pm 0.08 < 1$, and parameter $L_c$ is interpreted as the average percolation cluster length. At relatively low $E$, the electric field dependence of parameter $L_c$ is compatible with the law $L_c\propto E^{-0.911}$ which follows from directed percolation theory arguments.Comment: 17 pages, 8 figures; Fixed minor typos and updated reference

Momordica Cochinchinensis (Lour.) Spreng. (Cucurbitaceae) in culture in vitro

Momordica cochinchinensis (Lour.) Spreng. (Cucurbitaceae) belongs to a group of dioecious plants, forming the seeds with a very strong woody seed coat. To study the possibility of clonic micropropagation of M. cochinchinensis plants, the experiments were carried out by the introduction of this type in culture in vitro, and selecting the most appropriate methods of reproduction