BGRID: A block-structured grid generation code for wing sections

The operation of the BGRID computer program is described for generating block-structured grids. Examples are provided to illustrate the code input and output. The application of a fully implicit AF (approximation factorization)-based computer code, called TWINGB (Transonic WING), for solving the 3D transonic full potential equation in conservation form on block-structured grids is also discussed

Microbial mats of the Tswaing impact crater: results of a South African exobiology expedition and implications for the search for biological molecules on Mars

We describe microbial mats from the Tswaing impact crater in South Africa. The mats provide insights into the unique biological characteristics of impact craters and can help strategies for the search for biomolecules on Mars

Vertical variation of optical properties of mixed Asian dust/pollution plumes according to pathway of air mass transport over East Asia

© Author(s) 2015. This is an Open Access article made available under the terms of the Creative Commons Attribution License 3.0 https://creativecommons.org/licenses/by/3.0/We use five years (2009-2013) of multiwavelength Raman lidar measurements at Gwangju, South Korea (35.10° N, 126.53° E) for the identification of changes of optical properties of East Asian dust depending on its transport path over China. Profiles of backscatter and extinction coefficients, lidar ratios, and backscatter-related Ångström exponents (wavelength pair 355/532 nm) were measured at Gwangju. Linear particle depolarization ratios were used to identify East Asian dust layers. We used backward trajectory modeling to identify the pathway and the vertical position of dust-laden air masses over China during long-range transport. Most cases of Asian dust events can be described by the emission of dust in desert areas and subsequent transport over highly polluted regions of China. The Asian dust plumes could be categorized into two classes according to the height above ground at which these plumes were transported: (case I) the dust layers passed over China at high altitude levels (> 3 km) until arrival over Gwangju, and (case II) the Asian dust layers were transported near the surface and within the lower troposphere (< 3 km) over industrialized areas before they arrived over Gwangju. We find that the optical characteristics of these mixed Asian dust layers over Gwangju differ depending on their vertical position above ground over China and the change of height above ground during transport. The mean linear particle depolarization ratio was 0.21 ± 0.06 (at 532 nm), the mean lidar ratios were 52 ± 7 sr at 355 nm and 53 ± 8 sr at 532 nm, and the mean Ångström exponent was 0.74 ± 0.31 for case I. In contrast, plumes transported at lower altitudes (case II) showed low depolarization ratios (0.13 ± 0.04 at 532 nm), and higher lidar ratio (63 ± 9 sr at 355 nm and 62 ± 8 sr at 532 nm) and Ångström exponents (0.98 ± 0.51). These numbers show that the optical characteristics of mixed Asian plumes are more similar to optical characteristics of urban pollution. We find a decrease of the linear depolarization ratio of the mixed dust/pollution plume depending on transport time if the pollution layer traveled over China at low heights, i.e., below approximately 3 km above ground. In contrast, we do not find such a trend if the dust plumes traveled at heights above 3 km over China. We need a longer time series of lidar measurements in order to determine in a quantitative way the change of optical properties of dust with transport time.Peer reviewedFinal Published versio

Vacuum properties of a Non-Local Thirring-Like Model

We use path-integral methods to analyze the vacuum properties of a recently proposed extension of the Thirring model in which the interaction between fermionic currents is non-local. We calculate the exact ground state wave functional of the model for any bilocal potential, and also study its long-distance behavior. We show that the ground state wave functional has a general factored Jastrow form. We also find that it posess an interesting symmetry involving the interchange of density-density and current-current interactions.Comment: 25 pages, latex, no figure

Condensate deformation and quantum depletion of Bose-Einstein condensates in external potentials

The one-body density matrix of weakly interacting, condensed bosons in external potentials is calculated using inhomogeneous Bogoliubov theory. We determine the condensate deformation caused by weak external potentials on the mean-field level. The momentum distribution of quantum fluctuations around the deformed ground state is obtained analytically, and finally the resulting quantum depletion is calculated. The depletion due to the external potential, or potential depletion for short, is a small correction to the homogeneous depletion, validating our inhomogeneous Bogoliubov theory. Analytical results are derived for weak lattices and spatially correlated random potentials, with simple, universal results in the Thomas-Fermi limit of very smooth potentials.Comment: 17 pages, 4 figures. v2: published version, minor change

Metallic characteristics in superlattices composed of insulators, NdMnO3/SrMnO3/LaMnO3

We report on the electronic properties of superlattices composed of three different antiferromagnetic insulators, NdMnO3/SrMnO3/LaMnO3 grown on SrTiO3 substrates. Photoemission spectra obtained by tuning the x-ray energy at the Mn 2p -> 3d edge show a Fermi cut-off, indicating metallic behavior mainly originating from Mn e_g electrons. Furthermore, the density of states near the Fermi energy and the magnetization obey a similar temperature dependence, suggesting a correlation between the spin and charge degrees of freedom at the interfaces of these oxides

Counting Yang-Mills Dyons with Index Theorems

We count the supersymmetric bound states of many distinct BPS monopoles in N=4 Yang-Mills theories and in pure N=2 Yang-Mills theories. The novelty here is that we work in generic Coulombic vacua where more than one adjoint Higgs fields are turned on. The number of purely magnetic bound states is again found to be consistent with the electromagnetic duality of the N=4 SU(n) theory, as expected. We also count dyons of generic electric charges, which correspond to 1/4 BPS dyons in N=4 theories and 1/2 BPS dyons in N=2 theories. Surprisingly, the degeneracy of dyons is typically much larger than would be accounted for by a single supermultiplet of appropriate angular momentum, implying many supermutiplets of the same charge and the same mass.Comment: 34 pages, 1 figure, LaTe

Generation of the auroral kilometric radiation

For abstract, see A82-3554