Inverse problems with partial data for a Dirac system: A Carleman estimate approach

We prove that the material parameters in a Dirac system with magnetic and electric potentials are uniquely determined by measurements made on a possibly small subset of the boundary. The proof is based on a combination of Carleman estimates for first and second order systems, and involves a reduction of the boundary measurements to the second order case. For this reduction a certain amount of decoupling is required. To effectively make use of the decoupling, the Carleman estimates are established for coefficients which may become singular in the asymptotic limit.     

Ultraviolet B irradiation affects resistance of rainbow trout (Oncorhynchus mykiss) against bacterium Yersinia ruckeri and trematode Diplostomum spathaceum

Ultraviolet B (UVB) radiation is known to have various effects on the immune system of fish, but the effect on the actual disease resistance has remained largely unknown. Here we studied the effect of UVB on the resistance of rainbow trout (Oncorhynchus mykiss) against a bacterium Yersinia ruckeri, the causative agent of enteric red mouth disease, and a trematode parasite Diplostomum spathaceum, which causes cataracts in fish. The fish were exposed to UVB irradiation seven times in 14 days, and inoculated intraperitoneally with Y. ruckeri on day 5 after the first irradiation. On day 2 postinfection (p.i.), the number of viable bacteria in the kidney was lower in UVB-exposed than in unexposed fish. However, on day 8 p.i., UVB-irradiated fish had not been able to clear remaining Y. ruckeri effectively, and had a slightly higher bacterial load than controls. A similar, although not significant, effect was seen in the bacterial numbers in spleen. In the other experiment, fish were exposed to UVB for six consecutive days and then exposed to D. spathaceum. A significantly higher number of parasites was detected in the eyes of irradiated fish, indicating reduced resistance against the pathogen. Furthermore, UVB-irradiation altered the immunological and hematological parameters of fish, which also verified the immunomodulatory potential of UVB in the present study.     

Structure of the disturbed region of the atmosphere after the nuclear explosion in Hiroshima

An attempt is undertaken to describe the development of the disturbed region of the atmosphere caused by the nuclear explosion over Hiroshima on August 6, 1945. Numerical simulation of the phenomenon is performed using the dynamic equations for a nonconducting inviscid gas taking into account the combustion of urban buildings, phase changes of water, electrification of ice particles, and removal of soot particles. The results of the numerical calculation of the development of the disturbed region indicate heavy rainfall, the formation of a storm cloud with lightning discharges, removal of soot particles, and the formation of vertical vortices. The temporal sequence of these meteorological phenomena is consistent with the data of observations. Because of the assumptions and approximations used in solving the problem, the results are of qualitative nature. Refinement of the results can be obtained by a more detailed study of the approximate initial and boundary conditions of the problem.     

Microbiological methods for testing disinfectant efficiency on Pseudomonas biofilm

Biofilms of the Gram-negative bacteria Pseudomonas aeruginosa and Pseudomonas fragi were grown on stainless steel surfaces (AISI 304, 2B) for 4 days in slime broth. These biofilms were treated with four commercial disinfectants. The disinfectants were alcohol-based, tenside-based, peroxide-based and chlorine-based products, covering most disinfectant types used in the food industry. The effects of the disinfectants on the bacterial cells were first investigated in suspension using the permeabilisation test, which is based on fluorescence assessment of hydrophobic 1-N-phenyl-naphtylamine (NPN). The surfaces covered with disinfectant-treated biofilms were investigated using conventional cultivation, impedimetry and epifluorescence microscopy in combination with image analysis of preparations stained with the DNA-stain acridine orange and with the metabolic indicator system CTC-DAPI. The results showed that the tenside-based and peroxide-based disinfectants permeabilised the cells in suspension. The overall biofilm results showed that of the agents tested, the peroxide-based and chlorine-based disinfectants acted most effectively on cells in biofilms.     

The attenuated ray transform for connections and Higgs fields

We show that for a simple surface with boundary the attenuated ray transform in the presence of a unitary connection and a skew-Hermitian Higgs field is injective modulo the natural obstruction for functions and vector fields. We also show that the connection and the Higgs field are uniquely determined by the scattering relation modulo a gauge transformation. The proofs involve a Pestov type energy identity for connections together with holomorphic gauge transformations which arrange the curvature of the connection to have definite sign.     

The Gould-Jacobs Reaction of5-Aminoquinoxaline

 Reaction of 5-aminoquinoxaline with alkoxymethylene derivatives affords the corresponding quinoxalinoaminoethylenes. These undergo a thermal cyclization to yield angularly annelated 10H-pyrido[2,3-f]quinoxalines. The structures of all products were deduced from their IR, UV, mass, ¹H, and ¹³C NMR spectra.     

Potassium and ammonium dihydrogen phosphates activated with thallium: Growth and luminescence and scintillation properties

The conditions for the growth of potassium dihydrogen phosphate (KDP) and ammonium dihydrogen phosphate (ADP) crystals with concentrations of the thallium activator in the initial solution of 0.01, 0.1, and 1.0 wt % are investigated. It is shown that the character of incorporation and distribution of thallium in the KDP and ADP lattices is limited, apparently, by the difference in the ionic radii of K⁺, NH ₄ ⁺ , and Tl⁺ cations and the charge state of prismatic {100} and pyramidal {101} growth planes. Doping of KDP and ADP with thallium (to 0.1 and 1.0 wt %, respectively) does not deteriorate the structural quality of these crystals. The dependence of the lattice parameters a and c on the thallium impurity concentration is investigated. The absorption bands of thallium in the KDP:Tl⁺ and ADP:Tl⁺ crystals peak at 218 and 215 nm, respectively, while the photoluminescence band peaks at 280 nm for both types of crystals. The relative light yield upon excitation of scintillations by α particles (Pu²³⁹) and β particles (Bi²⁰⁷) is measured.     

Structure and reactivity of Pd doped Ag surfaces

We have performed first principles calculations for clean and Pd doped Ag(1 1 1) and Ag(1 0 0) surfaces, with and without adsorbed O and CO. Our results for the structure of the Pd doped Ag surfaces indicate that Pd atoms are located lower than the surrounding Ag surface atoms. We find that O atoms adsorbed on Pd doped Ag(1 1 1) reside at the fcc hollow sites, the site next to Pd being slightly favored. Moreover, we provide results for O and CO co-adsorption on the clean and Pd doped Ag(1 1 1) surfaces, indicating that Pd can act as an electronic promoter for the CO oxidation reaction.     

Preference programming for robust portfolio modeling and project selection

In decision analysis, difficulties of obtaining complete information about model parameters make it advisable to seek robust solutions that perform reasonably well across the full range of feasible parameter values. In this paper, we develop the Robust Portfolio Modeling (RPM) methodology which extends Preference Programming methods into portfolio problems where a subset of project proposals are funded in view of multiple evaluation criteria. We also develop an algorithm for computing all non-dominated portfolios, subject to incomplete information about criterion weights and project-specific performance levels. Based on these portfolios, we propose a project-level index to convey (i) which projects are robust choices (in the sense that they would be recommended even if further information were to be obtained) and (ii) how continued activities in preference elicitation should be focused. The RPM methodology is illustrated with an application using real data on road pavement projects.