Crossover of magnetoconductance autocorrelation for a ballistic chaotic quantum dot

The autocorrelation function C_{\varphi,\eps}(\Delta\varphi,\,\Delta \eps)= \langle \delta g(\varphi,\,\eps)\, \delta g(\varphi+\Delta\varphi,\,\eps+\Delta \eps)\rangle ($\varphi$ and \eps are rescaled magnetic flux and energy) for the magnetoconductance of a ballistic chaotic quantum dot is calculated in the framework of the supersymmetric non-linear $\sigma$-model. The Hamiltonian of the quantum dot is modelled by a Gaussian random matrix. The particular form of the symmetry breaking matrix is found to be relevant for the autocorrelation function but not for the average conductance. Our results are valid for the complete crossover from orthogonal to unitary symmetry and their relation with semiclassical theory and an $S$-matrix Brownian motion ensemble is discussed.Comment: 7 pages, no figures, accepted for publication in Europhysics Letter

Integro-Difference Equation for a correlation function of the spin-12{1\over2} Heisenberg XXZ chain

We consider the Ferromagnetic-String-Formation-Probability correlation function (FSFP) for the spin-$1\over 2$ Heisenberg XXZ chain. We construct a completely integrable system of integro-difference equations (IDE), which has the FSFP as a $\tau$-function. We derive the associated Riemann-Hilbert problem and obtain the large distance asymptotics of the FSFP correlator in some limiting cases.Comment: 14 pages, latex+epsf, 1 figur

Thermodynamic performance testing of the orbiter flash evaporator system

System level testing of the space shuttle orbiter's development flash evaporator system (FES) was performed in a thermal vacuum chamber capable of simulating ambient ascent, orbital, and entry temperature and pressure profiles. The test article included the evaporator assembly, high load and topping exhaust duct and nozzle assemblies, and feedwater supply assembly. Steady state and transient heat load, water pressure/temperature and ambient pressure/temperature profiles were imposed by especially designed supporting test hardware. Testing in 1978 verified evaporator and duct heater thermal design, determined FES performance boundaries, and assessed topping evaporator plume characteristics. Testing in 1979 combined the FES with the other systems in the orbiter active thermal control subsystem (ATCS). The FES met or exceeded all nominal and contingency performance requirements during operation with the integrated ATCS. During both tests stability problems were encountered during steady state operations which resulted in subsequent design changes to the water spray nozzle and valve plate assemblies

Determinant representation for a quantum correlation function of the lattice sine-Gordon model

We consider a completely integrable lattice regularization of the sine-Gordon model with discrete space and continuous time. We derive a determinant representation for a correlation function which in the continuum limit turns into the correlation function of local fields. The determinant is then embedded into a system of integrable integro-differential equations. The leading asymptotic behaviour of the correlation function is described in terms of the solution of a Riemann Hilbert Problem (RHP) related to the system of integro-differential equations. The leading term in the asymptotical decomposition of the solution of the RHP is obtained.Comment: 30 pages Latex2e, 2 Figures, epsf. Significantly extended and revised versio

Individual fMRI maps of all phalanges and digit bases of all fingers in human primary somatosensory cortex.

This study determined the individual maps of all fingers in Brodmann area 3b of the human primary somatosensory cortex in a single fMRI session by tactile stimulation at 19 sites across all phalanges and digit bases of the 5 right-hand digits. To quantify basic features of the digit maps within and across subjects, we applied standard descriptive measures, but also implemented a novel quantitative analysis. This so-called Direction/Order (DiOr) method tested whether subjects exhibited an ordering of peak fMRI representations along their individual direction of alignment through the set of analyzed phalanges and whether these individual directions were similar across subjects. Across-digit analysis demonstrated that for each set of homologous phalanges, the D5-to-D1 representations were successively represented along a common direction of alignment. Hence, the wellknown mediolateral D5-to-D1 somatotopy was not only confirmed for the distal phalanges (pi), but could also be shown for the medial (p2) and proximal phalanges (p3). In contrast, the peak activation for the digit bases (p4) only partly elicited that digit succession. Complementary, intra-digit analysis revealed a divergent picture of map topography for the different digits. Within D5 (and in a trend: D4), an ordered pl-to-p3 succession was found across subjects, pointing to a consistent intra-digit somatotopy for D5, with p3 generally found medial-posterior to pl. In contrast, for D1, D2, and D3, most subjects did not present with ordered pl-to-p3 maps nor were directions of alignment similarly oriented between subjects. These digits therefore exhibited highly diverse representation patterns across subjects

Crossbreeding beef cattle, III

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Soft Particle Spectrometer, Langmuir Probe, and Data Analysis for Aerospace Magnetospheric/Thermospheric Coupling Rocket Program

Under this grant two instruments, a soft particle spectrometer and a Langmuir probe, were refurbished and calibrated, and flown on three instrumented rocket payloads as part of the Magnetosphere/Thermosphere Coupling program. The flights took place at the Poker Flat Research Range on February 12, 1994 (T(sub o) = 1316:00 UT), February 2, 1995 (T(sub o) = 1527:20 UT), and November 27, 1995 (T(sub o) = 0807:24 UT). In this report the observations of the particle instrumentation flown on all three of the flights are described, and brief descriptions of relevant geophysical activity for each flight are provided. Calibrations of the particle instrumentation for all ARIA flights are also provided

Cerebral metabolism in man after acute stroke: new observations using localized proton NMR spectroscopy.

Localized proton NMR spectroscopy at 1.5 T using stimulated echoes has been applied to study metabolic alterations in the postischemic phase of patients with acute cerebral infarction. A complete depletion of N-acetyl aspartate in the area of infarction has been observed in a patient studied 4 days after stroke. This finding was paralleled by a dramatic increase in the concentration of lactic acid to about 16 mM within the lesion, indicating continued anaerobic glycolysis. The diluting effect of the edema has been estimated to reduce average metabolite concentrations by about a factor of 3

Friedel Oscillations in the Open Hubbard Chain

Using the Density Matrix Renormalization Group (DMRG), we calculate critical exponents for the one-dimensional Hubbard model with open boundary conditions with and without additional boundary potentials at both ends. A direct comparison with open boundary condition Bethe Ansatz calculations provides a good check for the DMRG calculations on large system sizes. On the other hand, the DMRG calculations provide an independent check of the predictions of Conformal Field Theory, which are needed to obtain the critical exponents from the Bethe Ansatz. From Bethe Ansatz we predict the behaviour of the 1/L-corrected mean value of the Friedel oscillations (for the density and the magnetization) and the characteristic wave vectors, and show numerically that these conjectures are fulfilled with and without boundary potentials. The quality of the numerical results allows us to determine, for the first time, the behaviour of the coefficients of the Friedel oscillations as a function of the the Hubbard interaction.Comment: 12 pages, 16 figures; submitted to Phys. Rev.

An Electron Sensor for the Pulsating Aurora 2 (Pulsaur 2) Mission

The purpose of this grant was to provide a low-energy electron detector to be flown on the PULSAUR 2 rocket payload for investigation of the pulsating aurora. In the course of this grant, the instrument, a tophat analyzer, was built and calibrated by the combined efforts of Southwest Research Institute, Mullard Space Sciences Laboratory, Rutherford Appleton Laboratory, and Goddard Space Flight Center, and successfully flown into an active, early morning, pulsating aurora over Andoya, Norway, on February 9, 1994. This report provides a description of the instrument and its calibration and gives examples of data obtained on the flight