Euclidean Thermal Green Functions of Photons in Generalized Euclidean Rindler Spaces for any Feynman-like Gauge

The thermal Euclidean Green functions for Photons propagating in the Rindler wedge are computed employing an Euclidean approach within any covariant Feynman-like gauge. This is done by generalizing a formula which holds in the Minkowskian case. The coincidence of the found (\be=2\pi)-Green functions and the corresponding Minkowskian vacuum Green functions is discussed in relation to the remaining static gauge ambiguity already found in previous papers. Further generalizations to more complicated manifolds are discussed. Ward identities are verified in the general case.Comment: 12 pages, standard latex, no figures, some signs changed, more comments added, final version to appear on Int. J. Mod. Phys.

Controlling the Spin Polarization of the Electron Current in a Semimagnetic Resonant-Tunneling Diode

The spin filtering effect of the electron current in a double-barrier resonant-tunneling diode (RTD) consisting of ZnMnSe semimagnetic layers has been studied theoretically. The influence of the distribution of the magnesium ions on the coefficient of the spin polarization of the electron current has been investigated. The dependence of the spin filtering degree of the electron current on the external magnetic field and the bias voltage has been obtained. The effect of the total spin polarization of the electron current has been predicted. This effect is characterized by total suppression of the spin-up component of electron current, that takes place when the Fermi level coincides with the lowest Landau level for spin-up electrons in the RTD semimagnetic emitter

D-Brane Interactions in a Gravitational Shock Wave Background

We study D-branes in the background of a gravitational shock wave. We consider the case of parallel D-branes located on opposite sides with respect to the shock wave. Their interaction is studied by evaluating the cylinder diagram using the boundary states technique. Boundary states are defined at each D-brane and their scalar product is evaluated after propagation through the shock wave. Taking the limit where the gravitational shock wave vanishes we show that the amplitude evaluated is consistent with the flat space-time result.Comment: To be published in Modern Physics Letters A, revised version with references added, 12 page

Tolerância de ovinos ao hidróxido de sódio e/ou sódio residual contido em cama de frangos de corte.

Resumo: Foram utilizados 18 ovinos da raca Corriedale, num delineamento em blocos inteiramente casualizados, com um arranjo fatorial 2 x 3, dois tipos de cama de frangos de corte, cama de casca de arroz (CCA) e cama de palha de arroz (CPA) e tres niveis de NaOH (zero, 6% e 12%). O consumo de sodio, consumo de agua, producao urinaria e a relacao de Na: Kurinaria foram significativamente (P0,05). O pH da urina mostrou tendencia a se elevar somente a medida que foram aumentados os niveis de alcali na dieta dos animais. O pH ruminal parece nao ter sido afetado pelo consumo das dietas tratadas com NaOH. O balanco de sodio foi negativo e inversamente relacionado com o consumo deste mineral, nao havendo dados suficientes que permitam a explicacao deste fato. [Sheep tolerance to sociu hydroxide and/or residual contents in the broiler litter]. Sheep tolerance to sodium hydroxide (NaOH) treated diets was studied. Eighteen Corriedale sheep were used in a completely randomized block design, witha 2 x 3 factorial arrangement. The design included two types of brolier litter lone composed of rice huiis and the other one of rice straw) and three leveis of NaOH (zero, 6% and 12%). Water and Na intakes, urine excretion and Na: K urinary ratio, increased (P 0.05) when yield increased. The urine pH showed only a tendency of increasing when the alkaii treatment in the animal diet increased. No effect of the NaOH treatments on the ruminal pH was detected. Sodium balance was negative and inversely related to the Na intake. However, there were not enough data fora ciear explanation of this fact

Exact Multifractal Spectra for Arbitrary Laplacian Random Walks

Iterated conformal mappings are used to obtain exact multifractal spectra of the harmonic measure for arbitrary Laplacian random walks in two dimensions. Separate spectra are found to describe scaling of the growth measure in time, of the measure near the growth tip, and of the measure away from the growth tip. The spectra away from the tip coincide with those of conformally invariant equilibrium systems with arbitrary central charge $c\leq 1$, with $c$ related to the particular walk chosen, while the scaling in time and near the tip cannot be obtained from the equilibrium properties.Comment: 4 pages, 3 figures; references added, minor correction

International Space Station Payload Training Overview

This paper describes payload crew training-related activities performed by NASA and the U.S. Payload Developer (PD) community for the International Space Station (ISS) Program. It describes how payloads will be trained and the overall training planning and integration process. The overall concept, definition, and template for payload training are described. The roles and responsibilities of individuals, organizations, and groups involved are discussed. The facilities utilized during payload training and the primary processes and activities performed to plan, develop, implement, and administer payload training for ISS crews are briefly described. Areas of improvement to crew training processes that have been achieved or are currently being worked are identified