Late time neutrino masses, the LSND experiment, and the cosmic microwave background

Models with low-scale breaking of global symmetries in the neutrino sector provide an alternative to the seesaw mechanism for understanding why neutrinos are light. Such models can easily incorporate light sterile neutrinos required by the Liquid Scintillator Neutrino Detector experiment. Furthermore, the constraints on the sterile neutrino properties from nucleosynthesis and large-scale structure can be removed due to the nonconventional cosmological evolution of neutrino masses and densities. We present explicit, fully realistic supersymmetric models, and discuss the characteristic signatures predicted in the angular distributions of the cosmic microwave background.     

Dilute solutions of polyelectrolytes—IV. Unperturbed dimensions of N,N-diethylacrylamide-N,N-dimethyldiallylammonium chloride copolymers

The behaviour of copolymers of N,N-diethylacrylamide with N,N-dimethyldiallylammonium chloride in aqueous NaCl solution has been studied by light-scattering. The parameters characterizing the short- and long-range interactions have been calculated. The influence of copolymer composition on the gyration radius and unperturbed dimensions shows that the macromolecules have maximum flexibility for a composition near equimolar. This behaviour was attributed to decrease of both the electrostatic repulsions and the steric hindrance of the structural units, as a result of pronounced alternation.     

Radiation induced chemisorption of oxygen on chromia

The effect of nuclear radiation on the chemisorption of oxygen on Cr₂O₃, Cr₂O₃-Al₂O₃ and Cr₂O₃-SnO₂ catalysts has been studied. An iodometric method was used to measure the amount of chemisorbed oxygen; simultaneously the increase in the catalytic activity of the catalyst in the decomposition of H₂O₂ was determined. It was found that the radiation present within a nuclear reactor promotes the chemisorption of oxygen on chromia (either pure or supported on Al₂O₃ or SnO₂) at temperatures at which such a chemisorption does not normally occur. The radiochemisorption of oxygen on chromia increases with the degree of dispersion of chromia on Al₂O₃ or SnO₂ and is accompanied by an increased catalytic activity of this catalyst in the decomposition reaction of H₂O₂. It seems that the radiochemisorption is largely due to the action of γ-rays and fast neutrons on the gas.     

Common Dynamic Properties of Biosignals During Cognition: Self-Similarity and Chaotic Dynamics of Both Response Times and EEG During Movement Imagery

This study was undertaken to verify whether different output variables or biosignals, measured during performance of a cognitive task, manifest common dynamical properties. Nonlinear properties of both response times (RTs) and electroercephalograms (EEG) were tested. We asked subjects to generate mental images of actions following of auditorily presentation simple phrases suggesting the action. Analysis of RT series combined from many subjects and of EEG records from single subjects clearly manifested self-similarity and chaotic dynamics that provide insights into the self-organization of the brain/behavioral system.     

Ugi reaction in aqueous solutions: A simple protocol for libraries production

A reaction between levulinic acid, isocyanides and primary amines has been examined in distilled water and in surfactants solutions. It is demonstrated that the reaction gives good results at the different concentrations including one well above the solubility limit. A simple and eco-friendly protocol for libraries production is described.     

Valence charge concentrations, electron delocalization and beta-agostic bonding in d0 metal alkyl complexes

In this paper we describe a range of model d(0) metal ethyl compounds and related complexes, studied by DFT calculations and high resolution X-ray diffraction. The concept of ligand-opposed charge concentrations (LOCCs) for d(0) metal complexes is extended to include both cis-and trans-ligand-induced charge concentrations (LICCs) at the metal, which arise as a natural consequence of covalent metal-ligand bond formation in transition metal alkyl complexes. The interplay between locally induced sites of increased Lewis acidity and an ethyl ligand is crucial to the development of a beta-agostic interaction in d(0) metal alkyl complexes, which is driven by delocalization of the M-C bonding electrons. Topological analysis of theoretical and experimental charge densities reveals LICCs at the metal atom, and indicates delocalization of the M-C valence electrons over the alkyl fragment, with depletion of the metal-directed charge concentration (CC) at the alpha-carbon atom, and a characteristic ellipticity profile for the C(alpha)-C(beta) bond. These ellipticity profiles and the magnitude of the CC values at C(alpha) and C(beta) provide experimentally observable criteria for assessing quantitatively the extent of delocalization, with excellent agreement between experiment and theory. Finally, a concept is proposed which promises systematic control of the extent of C-H activation in agostic complexes.     

Best values for the CP-odd meson–nucleon couplings from supersymmetry

In the supersymmetric models, the dominant sources of the hadronic flavor-diagonal CP violation at low energy are the theta term and the chromoelectric dipole moments of quarks. Using QCD sum rules, we estimate the preferred range and the best values for the CP-odd meson–nucleon coupling constants induced by these operators. When the theta term is removed by the axion mechanism, the size of the most important isospin triplet pion–nucleon coupling is estimated to be , where chromoelectric dipole moments are given in units of 10⁻²⁶ cm.     

Comparative investigation of zein isolated from gluten by various methods

A comparative study has been made on zein preparations isolated from gluten by extraction with 70% ethanol and precipitation under various conditions; by dialysis, and by the addition of a 0.1 M solution of sodium sulfate or of acetone. An investigation of absorption spectra and of electrophoresis in polyacrylamide gel has shown the advantage of the method using acetone for precipitating the protein preparation.     

Computation of flow over a spherically blunted cone for various shock layer and surface blowing conditions

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 2, pp. 100–106, March–April, 1991.     

Shelah's pcf theory and its applications

This is a survey paper giving a self-contained account of Shelah's theory of the pcf function pcf(a)={cf(Πa/D, <_D):D is an ultrafilter on a}, where a is a set of regular cardinals such that |a|a). We also give several applications of the theory to cardinal arithmetic, the existence of Jonsson algebras, and partition calculus.