Absence of symmetry breaking for systems of rotors with random interactions

We prove that Gibbs states for the Hamiltonian , with thes _x varying on theN-dimensional unit sphere, obtained with nonrandom boundary conditions (in a suitable sense), are almost surely rotationally invariant if withJ _xy i.i.d. bounded random variables with zero average, 1 in one dimension, and 2 in two dimensions.     

A dominance-based rough set approach applied to evaluate the credit risk of sovereign bonds

4OR - Even though sovereign bonds represent low-risk alternatives that give investors a healthy income, the risk assessment process for these bonds is still considered subjective because of the...     

Biosensors designed for environmental and food quality control based on screen-printed graphite electrodes with different configurations

Graphite electrodes fabricated by screen-printing have been used as amperometric detectors in biosensors based on NAD(+)-dependent dehydrogenases, tyrosinase, or genetically modified acetylcholinesterases. The mono-enzyme sensors have been optimized as disposable or reusable devices for detection of a variety of substrates important in the food industry ( D-lactic acid, L-lactic acid, acetaldehyde) or in environmental pollution control (phenols and dithiocarbamate, carbamate and organophosphorus pesticides). The sensors were prepared in four configurations differing in enzyme confinement, enzyme immobilization and location of the immobilization agent in the biosensor assembly. Tests on real samples have been performed with the biosensors; D-lactic acid and acetaldehyde have been detected in wine and phenols in air.     

Energy-filtered XPEEM with NanoESCA using synchrotron and laboratory X-ray sources: Principles and first demonstrated results

The importance of energy filtering in PEEM-based imaging methods has been shown in recent years with the availability of powerful instruments. A new instrument, the NanoESCA, combines a fully electrostatic PEEM column and an aberration corrected double hemispherical analyser as energy filter. This paper reports on recently demonstrated XPEEM results using the first commercially available NanoESCA instrument operated with both synchrotron soft X-rays and monochromatic laboratory Al Kα radiation. The implementation of elemental and bonding-state specific imaging is shown with both excitation sources. The presently achieved (but not yet ultimate) lateral resolutions on energy filtered core-level images are 150 nm with a large synchrotron spot and below 1 μm with a focused laboratory source. To date this is the unique example of laboratory XPEEM core-level imaging.     

Magnetic field induced orbital polarization in cubic YbInNi4: determining the quartet ground state using x-ray linear dichroism

We have been able to induce a linear dichroic signal in the Yb M(5) x-ray absorption white line of cubic YbInNi(4) by the application of a magnetic field. The nonzero integrated intensity of the magnetic field induced dichroic spectrum indicates a net noncubic 4f orbital polarization. A quantitative analysis of the temperature and field strength dependence establishes that the crystal-field ground state is a Γ(8) quartet. The results demonstrate the potential of magnetic field induced linear dichroism as a new powerful approach for the investigation of the degeneracy and orbital degrees of freedom of cubic heavy-fermion and Kondo systems.