Presence of nitrate and nitrite in cow forage, plasma, and milk

Even if plants can contain high levels of nitrate and nitrite, milk and dairy products are not described as sources of these anions. The purpose of this paper was to measure the concentrations of nitrate and nitrite in forage, cow blood, and milk.The results show that the nitrate ratio of milk to plasma is very low, suggesting that milk contamination with nitrate is unlikely to occur. This finding also proves the lack of an active transport mechanism to transfer nitrate from blood to milk. The nitrite anion almost disappears from milk through an enzymatic conversion; usually levels of μg l−1 were measured

Influence of the Characteristics of the STM-tip on the Electroluminescence Spectra

We analyze the influence of the characteristics of the STM-tip (applied voltage, tip radius) on the electroluminescence spectra from an STM-tip-induced quantum dot taking into account the many-body effects. We find that positions of electroluminescence peaks, attributed to the electron-hole recombination in the quantum dot, are very sensitive to the shape and size of the confinement potential as determined by the tip radius and the applied voltage. A critical value of the tip radius is found, at which the luminescence peak positions as a function of the tip radius manifest a transition from decreasing behavior for smaller radii to increasing behavior for larger radii. We find that this critical value of the tip radius is related to the confinement in the lateral and normal direction.Comment: 15 pages, 5 figure

Superstripes and complexity in high-temperature superconductors

While for many years the lattice, electronic and magnetic complexity of high-temperature superconductors (HTS) has been considered responsible for hindering the search of the mechanism of HTS now the complexity of HTS is proposed to be essential for the quantum mechanism raising the superconducting critical temperature. The complexity is shown by the lattice heterogeneous architecture: a) heterostructures at atomic limit; b) electronic heterogeneity: multiple components in the normal phase; c) superconducting heterogeneity: multiple superconducting gaps in different points of the real space and of the momentum space. The complex phase separation forms an unconventional granular superconductor in a landscape of nanoscale superconducting striped droplets which is called the "superstripes" scenario. The interplay and competition between magnetic orbital charge and lattice fluctuations seems to be essential for the quantum mechanism that suppresses thermal decoherence effects at an optimum inhomogeneity.Comment: 20 pages, 3 figures; J. Supercon. Nov. Mag. 201

Orientational Effect of the In-Plane Magnetic Field on the FFLO Modulation in Layered Superconductors

We present the analysis of the Fulde-Ferrell-Larkin-Ovchinnikov phase in an s-wave superconducting layered system in parallel magnetic field. We show that in the close vicinity of the tricritical point in the system with elliptical Fermi surface the orbital effect pins the FFLO modulation vector perpendicular to the applied magnetic field. At low temperatures, the FFLO modulation can acquire different directions.Superconductivity in quantum-size regimeNew Century of Superconductivity: Ideas, Materials, Technologie

Electroluminescence spectra of an AFM-Tip-Induced quantum dot

Abstract only

Electroluminescence spectra of an STM-tip-induced quantum dot

We analyse the electroluminescence measurements performed on a STM-tipImduced quantum dot in a GaAs layer. Positions of electroluminescence peaks, attributed to the electron-hole recombination in the quantum dot, are very sensitive to the electron tunnelling current even in the case when the current is weak and the effect of the electron charge on the electrostatic potential profile in the structure is negligible. We find, in agreement with experiment, that increasing voltage on the STM-tip results in a red shift of thel electroluminescence peaks, while the peak positions as a function of the electron tunnelling current reveal a blue shift