444 research outputs found
Anderson localization of classical waves in weakly scattering one-dimensional Levy lattices
© 2018 American Physical Society. Anderson localization of classical waves in weakly scattering one-dimensional Levy lattices is studied analytically and numerically. The disordered medium is composed of layers with alternating refractive indices and with thickness disorder distributed according to the Pareto distribution ∼1/x(α+1). In Levy lattices the variance (or both variance and mean) of a random parameter does not exist, which leads to a different functional form for the localization length. In this study an equation for the localization length is obtained, and it is found to be in excellent agreement with the numerical calculations throughout the spectrum. The explicit asymptotic equations for the localization lengths for both short and long wavelengths have been deduced. It is shown that the localization length tends to a constant at short wavelengths and it is determined by the layer interface Fresnel coefficient. At the long wavelengths the localization length is proportional to the power of the wavelength ∼λα for 12, where the variance of the random distribution exists, the localization length attains its classical long-wavelength asymptotic form ∼λ2
Complete gluon bremsstrahlung corrections to the process b -> s l+ l-
In a recent paper, we presented the calculation of the order (alpha_s)
virtual corrections to b->s l+ l- and of those bremsstrahlung terms which are
needed to cancel the infrared divergences. In the present paper we work out the
remaining order(alpha_s) bremsstrahlung corrections to b->s l+ l- which do not
suffer from infrared and collinear singularities. These new contributions turn
out to be small numerically. In addition, we also investigate the impact of the
definition of the charm quark mass on the numerical results.Comment: 20 pages including 11 postscript figure
Tolerance to freezing stress in Cicer accessions under controlled and field conditions
Freezing tolerance was determined in 5 annual wild Cicer and 225 Cicer arietinum L. accessions, grown both in field and controlled conditions. In controlled conditions, the temperature was decreased 5°C daily to achieve -20°C. Field trial was conducted at Urmia, Iran. In general, 'kabuli' chickpeas were more susceptible to freezing stress than 'desi' chickpeas. Some 'kabuli' types such as FLIP 93-261C and x03TH21 which presented high freezing tolerance during early seedling stage, withstood -15.6°Cwithout snow cover. Based on severity score data, the highest freezing tolerance sources were all accessions of Cicer echinospermum and Cicer reticulatum and 15 lines from C. arietinum germplasm. The results obtained in controlled conditions were approximately confirmed in the field conditions. The most resistant genotypes to freezing stress were wild accessions of ILWC 81, ILWC 106, ILWC 139, ILWC 181, ILWC 235, and cultivated lines, Sel 96 TH 11404, Sel 96 TH 11439, Sel 96 TH 11488, Sel 98 TH 11518, x03TH21 and FLIP 93-261C. Our results indicated the possibility of autumn sowing of chickpea in the high plateaus of Iran
Rare decays at the NLO
We present an independent calculation of matrix
elements of the QCD penguin operators for the decays . The Mellin-Barnes representation technique is applied for the
systematic numerical evaluation of involved two-loop diagrams. The numerical
effect of the calculated contributions is confirmed to be of order of 1%. We
also present an updated numerical analysis for
decay rates.Comment: 15 pages, 4 figure
Data mining of market information to assess at-home pork demand
This study analyzes the economic and demographic patterns of at-home pork consumption for representative individuals over 18 years of age in the United States. Three data sets purchased by the National Pork Board (NPB) are mined for this purpose: (1) National Eating Trends (NET) data from National Panel Diary (NPD) on individuals' intake and their demographic characteristics; (2) weekly retail prices for fresh meats and fresh pork cuts from FreshLook; and (3) weekly retail prices for processed pork products from A.C. Nielsen.
Heckman sample selection models are used to find demographic, health, and attitudinal/lifestyle patterns of consumption of twelve fresh and processed pork products as well as beef, chicken, and seafood. In the fall, individuals have a higher probability of eating beef, chicken, pork tenderloin, and bacon, but a lower probability of eating fresh seafood, canned ham, and smoked ham relative to the spring. The New England region has the highest likelihood of eating fresh pork, beef, chicken, seafood, pork roasts, pork tenderloin, and pork hotdogs. Blacks, on average, eat more fresh and processed pork, chicken, pork sausage, bacon, and canned ham, but less beef relative to whites. Concern about serving food with fat is negatively related with the likelihood of eating processed pork, lunchmeat, ham, and bacon, but it is positively related with the likelihood of eating pork hotdogs.
A three-stage selectivity-adjusted censored LA/AIDS model is developed and estimated to find demand-price relationships for: (1) fresh meats (pork, beef, chicken, and seafood) and (2) nine fresh and processed pork cuts. However, aggregate fresh meats are substitutes for each other in at-home market, but there are substantial complementarities between pork cuts. Pork sausage is the major competitor for the processed products, pork roasts and pork tenderloin, but a major complement for pork ribs. There is relatively week substitutability between pork and beef, and relatively strong substitutability between pork and chicken and between beef and chicken. This could suggest opportunities for some joint marketing efforts between pork and beef commodity interests.
This information can be used as a guide for marketing strategists for targeting and promotion as well as for category management of the disaggregated pork products
Photosensitive bismuth ions in lead tungstate
Electron paramagnetic resonance (EPR) signals of Bi2+ ions have been detected in the EPR spectrum of manganese-, bismuth-, and tin-doped PbWO4 single-crystals irradiated by xenon and mercury lamps at 100 K. The parameters of the Zeeman, hyperfine, and superhyperfine interactions and the localization of Bi2+ ions have been determined. © 2013 Pleiades Publishing, Ltd
Localisation and disorder in the design of 2D photonic crystal devices
Photonic crystals are meta-materials that can inhibit the propagation of light in all directions for specific wavelength ranges. Material or structural defects can be introduced into the crystal to cause localised modes, providing the ability to mould the flow of light on the wavelength scale and allowing the development of miniaturised, integrated photonic devices. For this reason, photonic crystals will likely be key building blocks for future micro-optical and communication technology. In this paper, we examine the Bloch mode modelling of 2D photonic crystal structures with application to the analysis of photonic crystal waveguides and their susceptibility to disorder, which provides a framework for studying fabrication tolerances in realistic devices
Local density of states of chiral Hall edge states in gyrotropic photonic clusters
We have constructed the Green's tensor for two-dimensional gyrotropic photonic clusters and have calculated their optical local density of states (LDOS). For clusters that support the chiral Hall edge states we calculate the LDOS as a function of wavele
Paramagnetic defects in manganese-doped lead tungstate
In manganese-doped PbWO4 crystals, low-intensity signals of triclinic clusters Mn4+-VO and Fe3+-VPb have been revealed in addition to signals of Mn2+ tetragonal centers. The Mn4+-VO cluster is formed by a Mn4+ ion in the W6+ position, which is associated with a vacancy of the nearest neighbor O2-ion, and the Fe3+-VPb cluster consists of a Fe3+ ion substituting for Pb2+ with a local compensation of by a lead vacancy. It has been shown that, in PbWO4: Mn, there is also a small amount of Mn4+ tetragonal centers located in the Pb2+ position with a nonlocal compensation of an excess charge. © 2013 Pleiades Publishing, Ltd
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