Full Counting Statistics of Charge Transfer in Coulomb Blockade Systems

Full counting statistics (FCS) of charge transfer in mesoscopic systems has recently become a subject of significant interest, since it proves to reveal an important information about the system which can be hardly assessed by other means. While the previous research mostly addressed the FCS of non- interacting systems, the present paper deals with the FCS in the limit of strong interaction. In this Coulomb blockade limit the electron dynamics is known to be governed by a master equation. We develop a general scheme to evaluate the FCS in such case, this being the main result of the work presented. We illustrate the scheme, by applying it to concrete systems. For generic case of a single resonant level we establish the equivalence of scattering and master equation approach to FCS. Further we study a single Coulomb blockade island with two and three leads attached and compare the FCS in this case with our recent results concerning an open dot either with two and three terminals. We demonstrate that Coulomb interaction suppresses the relative probabilities of large current fluctuations.Comment: 17 pages, 16 figure

Current and power spectrum in a magnetic tunnel device with an atomic size spacer

Current and its noise in a ferromagnetic double tunnel barrier device with a small spacer particle were studied in the framework of the sequential tunneling approach. Analytical formulae were derived for electron tunneling through the spacer particle containing only a single energy level. It was shown that Coulomb interactions of electrons with a different spin orientation lead to an increase of the tunnel magnetoresistance. Interactions can also be responsible for the negative differential resistance. A current noise study showed, which relaxation processes can enhance or reduce fluctuations leading either to a super-Poissonian or a sub-Poissonian shot noise.Comment: 12 pages, 4 figure

Functioning of defense systems in halophytes and glycophytes under progressing salinity

Six-week-old Plantago major L. and Thellungiella halophila Mey. plants were subjected to progressing salinity by a daily increase in the NaCl concentration by 100 mM until the final concentration of 400 mM. A dynamics of stress-dependent accumulation of Na+ and Cl- ions, proline, and free polyamines and also activities of antioxidant enzymes, superoxide oxidase (SOD) and free, ion-bound, and covalently bound guaiacol-dependent peroxidases was studied. We also examined the intensity of gene expression encoding enzymes of proline metabolism and polyamine biosynthesis. It was shown that the high salt-resistance of the halophyte T. halophila was determined by plant capability of ion accumulation and stress-dependent proline accumulation. An important role in the maintenance of this plant homeostasis under salinity plays a high constitutive levels of activities of three types of peroxidases tested and also of proline manifesting a polyfunctional protective action. In contrast, P. major plants characterized by a lower tolerance to salt excess did not display a high constitutive level of proline or the activity of guaiacol-dependent peroxidases; they also were not capable of stress-induced accumulation of compatible osmolytes and did not accumulate the salt. However, this glycophyte contained relatively much spermidine and active SOD, which provided for a decrease in the damaging effects of reactive oxygen species under salt shock. In both plant species, it was established that salinity changed the intracellular content of polyamines, which was not dependent on the activity of gene transcription encoding the enzymes of their biosynthesis. The results obtained support a hypothesis that halophytes and glycophytes have some common mechanisms of tolerance to salinity, but the control of these mechanisms differs substantially. © 2007 Pleiades Publishing, Ltd

Functioning of defense systems in halophytes and glycophytes under progressing salinity

Six-week-old Plantago major L. and Thellungiella halophila Mey. plants were subjected to progressing salinity by a daily increase in the NaCl concentration by 100 mM until the final concentration of 400 mM. A dynamics of stress-dependent accumulation of Na+ and Cl- ions, proline, and free polyamines and also activities of antioxidant enzymes, superoxide oxidase (SOD) and free, ion-bound, and covalently bound guaiacol-dependent peroxidases was studied. We also examined the intensity of gene expression encoding enzymes of proline metabolism and polyamine biosynthesis. It was shown that the high salt-resistance of the halophyte T. halophila was determined by plant capability of ion accumulation and stress-dependent proline accumulation. An important role in the maintenance of this plant homeostasis under salinity plays a high constitutive levels of activities of three types of peroxidases tested and also of proline manifesting a polyfunctional protective action. In contrast, P. major plants characterized by a lower tolerance to salt excess did not display a high constitutive level of proline or the activity of guaiacol-dependent peroxidases; they also were not capable of stress-induced accumulation of compatible osmolytes and did not accumulate the salt. However, this glycophyte contained relatively much spermidine and active SOD, which provided for a decrease in the damaging effects of reactive oxygen species under salt shock. In both plant species, it was established that salinity changed the intracellular content of polyamines, which was not dependent on the activity of gene transcription encoding the enzymes of their biosynthesis. The results obtained support a hypothesis that halophytes and glycophytes have some common mechanisms of tolerance to salinity, but the control of these mechanisms differs substantially. © 2007 Pleiades Publishing, Ltd

Role of antioxidant systems in wild plant adaptation to salt stress

Wild plants differing in the strategies of adaptation to salinity were grown for six weeks in the phytotron and then subjected to salt stress (100 mM NaCl, 24 h). The activities of principal antioxidant enzymes and the accumulation of sodium ions and proline were studied. Independently of the level of constitutive salt tolerance, plants of all species tested accumulated sodium ions under salinity conditions but differed in their capability of stress-dependent proline accumulation and superoxide dismutase (SOD) and guaiacol-dependent peroxidase activities. Proline-accumulating species were found among both halophytes (Artemisia lerchiana and Thellungiella halophila) and glycophytes (Plantago major and Mycelis muralis). The high activities of ionically-bound and covalently bound peroxidases were characteristic of Th. halophila plants. High constitutive and stress-induced SOD activities were, as a rule, characteristic of glycophytes with the low constitutive proline level: Geum urbanum and Thalictrum aquilegifolium. Thus, a negative correlation was found between proline content and SOD activity in wild species tested; it was especially bright in the halophyte Th. halophila and glycophyte G. urbanum. An extremely high constitutive and stress-induced levels of proline and peroxidase activity in Th. halophila maybe compensate SOD low activity in this plant, and this contributed substantially into its salt resistance. Thus, monitoring of stress-dependent activities of some antioxidant enzymes and proline accumulation in wild plant species allowed a supposition of reciprocal interrelations between SOD activity and proline accumulation. It was also established that the high SOD activity is not obligatory trait of species salt tolerance. Moreover, plants with the high activity of peroxidase and active proline accumulation could acclimate to salts stress (100 mM NaCl, 24 h) independently of SOD activity. © 2008 MAIK Nauka

Surface defects in hot rolling dual-phase corrosion-resisting steels

17.00; Translated from Russian (Interkristallitnaya Khrupkost' Stalei i Splavov, Sverdlovsk (SU), 1987 p. 78-84)Available from British Library Document Supply Centre- DSC:9023.19(VR-Trans--3561)T / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo