Realistic Dirac leptogenesis

We present a model of leptogenesis that preserves lepton number. The model maintains the important feature of more traditional leptogenesis scenarios: The decaying particles that provide the CP violation necessary for baryogenesis also provide the explanation for the smallness of the neutrino Yukawa couplings. This model clearly demonstrates that, contrary to conventional wisdom, neutrinos need not be Majorana in nature in order to help explain the baryon asymmetry of the universe.     

Invariants of linear maps on matrix algebras

Let L be a linear map on the space of n×n matrices over a field. We determine the structure of the maps L that preserve commutativity. We also determine the structure of all linear maps on complex matrices that preserve the higher numerical range. The main tool is the Fundamental Theorem of Projective Geometry.     

Analysis of some binary and ternary oxide mixtures by inelastic neutron scattering

Aluminium, iron and silicon have been determined in a number of binary and ternary oxide mixtures at levels>1% by measuring the gamma-lines emitted as a result of inelastic neutron scattering.     

Metal mirror selection guide

Several pertinent parameters are frequently overlooked in specifying metal mirrors for high energy laser systems. This report outlines the importance of those parameters and describes both the typical and the state-of-the-art characteristics presently available.     

Higher order convergence results for the Rayleigh-Ritz method applied to eigenvalue problems: 2. Improved error bounds for eigenfunctions

The application of the Rayleigh-Ritz method for approximating the eigenvalues and eigenfunctions of linear eigenvalue problems in several dimensions is investigated. The object is to improve upon known error estimates for the approximate eigenfunctions. Results for the Galerkin approximation of the eigenfunctions are developed under varying assumptions on the boundary conditions and domain of definition of the eigenvalue problem. These results, coupled with a previous result relating Galerkin and Rayleigh-Ritz approximation of the eigenfunctions, are then used to obtain improved error estimates for the approximate eigenfunctions in theL ² and uniform norms.This research was supported in part by AEC Grant (11-1)-2075.     

Silver(I)-catalyzed addition of zirconocenes to glycal epoxides. A new synthesis of alpha-C-glycosides

[reaction: see text] Hydrozirconation of terminal alkynes, followed by AgClO4-catalyzed in situ addition of the resultant alkenylzirconocenes to 1,2-anhydrosugars (glycal epoxides) leads to alpha-C-glycosides in moderate to high yields.     

On the invariance of classes under composition

The necessary and sufficient condition for to be in the class for every of that class whose range is in the domain of is that be in .

     

Improved signal-to-noise ratio in spectral-domain compared with time-domain optical coherence tomography

A signal-to-noise ratio (SNR) analysis is presented for optical coherence tomography (OCT) signals in which time-domain performance is compared with that of the spectral domain. A significant SNR gain of several hundredfold is found for acquisition in the spectral domain. The SNR benefit is demonstrated experimentally in a hybrid time-domain-spectral-domain OCT system.     

Zement

Ohne Zusammenfassung