Return to equilibrium

The problem of return to equilibrium is phrased in terms of aC*-algebraU, and two one-parameter groups of automorphisms , ^P corresponding to the unperturbed and locally perturbed evolutions. The asymptotic evolution, under , of ^P -invariant, and ^P -K.M.S., states is considered. This study is a generalization of scattering theory and results concerning the existence of limit states are obtained by techniques similar to those used to prove the existence, and intertwining properties, of wave-operators. Conditions of asymptotic abelianness provide the necessary dispersive properties for the return to equilibrium. It is demonstrated that the ^P -equilibrium states and their limit states are coupled by automorphisms with a quasi-local property; they are not necessarily normal with respect to one another. An application to theX–Y model is given which extends previously known results and other applications, and examples, are given for the Fermi gas.     

Entanglement of a photon and a collective atomic excitation

We describe a new experimental approach to probabilistic atom-photon (signal) entanglement. Two qubit states are encoded as orthogonal collective spin excitations of an unpolarized atomic ensemble. After a programmable delay, the atomic excitation is converted into a photon (idler). Polarization states of both the signal and the idler are recorded and are found to be in violation of the Bell inequality. Atomic coherence times exceeding several microseconds are achieved by switching off all the trapping fields--including the quadrupole magnetic field of the magneto-optical trap--and zeroing out the residual ambient magnetic field.     

Level structure of 22Mg: implications for the 21Na(p,gamma)22Mg astrophysical reaction rate and for the 22Mg Mass

The level structure of (22)Mg has been studied with high-sensitivity gamma-ray spectroscopy techniques. A complete level scheme is derived incorporating all subthreshold states and all levels in the energy region relevant for novae burning. The excitation energy of the most important astrophysical resonance is measured with improved accuracy and found to differ from previous values. Combining the present result with a recent resonance energy measurement of this state leads to a derived (22)Mg mass excess of -400.5(13) keV.     

Evidence for nontermination of rotational bands in 74Kr

Three rotational bands in 74Kr were studied up to (in one case one transition short of) the maximum spin I(max) of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I(max). This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I = I(max).     

Empirical modeling of human face kinematics during speech using motion clustering

In this paper we present an algorithm for building an empirical model of facial biomechanics from a set of displacement records of markers located on the face of a subject producing speech. Markers are grouped into clusters, which have a unique primary marker and a number of secondary markers with an associated weight. Motion of the secondary markers is computed as the weighted sum of the primary markers of the clusters to which they belong. This model may be used to produce facial animations, by driving the primary markers with measured kinematic signals.     

Quantum-noise-initiated symmetry breaking of spatial solitons

The spectra of chi(2) spatial solitons are measured close to the soliton-formation threshold and show the presence of sidebands, shifted by 39 THz from the laser line. By comparing with the predictions of a quantum optical field model, solved numerically in the full (3 + 1)-dimensional space, it is claimed that the observed temporal instability of the spatial soliton is seeded by vacuum state fluctuations of the electromagnetic field.     

Why is silver catalytically active for NO reduction? A unique pathway via an inverted (NO)2 dimer

NO reduction on the noble metal Ag has been studied using density functional theory calculations. It was found that monomeric NO dissociation is subject to prohibitive barriers on Ag metal and is thus unlikely to account for the experimental observations for NO reduction over Ag-based catalysts. For the first time, a mechanism via an inverted (NO)(2) dimer is identified, which can explain both the high activity and the selectivity of this catalytic system. N(2)O is the major reduction product of the inverted (NO)(2) dimer, in accord with experiment. The physical origin of the Ag metallic state as a good catalyst is furthermore identified: Ag surfaces, including small clusters, have little or no covalent bonding ability but can bond ionically with adsorbates. We conclude that the variation of the ionic bonding strength of Ag toward different reactants determines its catalytic selectivity.     

Quality control and quality assurance aspects of the routine use of capillary electrophoresis for serum and urine proteins in clinical laboratories

Using capillary electrophoresis (CE) for serum protein electrophoresis, the quality of results begins with monitoring a well-functioning instrument, using scrupulously clean capillaries, well-calibrated methods as well as regular use of an internal quality control material. Quality assurance programs are available in countries such as Australia, United Kingdom, United States, and European countries such as Sweden and Germany. The present commercial control material that is available gives percentages of albumin, alpha 1, alpha 2, beta- and gamma-globulins, the gamma-component being of normal distribution, and not containing any monoclonal protein component. We feel that a quantitative commercial control material containing a monoclonal protein at decision level for treating myeloma patients would be beneficial to all laboratories as a serum protein electrophoresis control, whether the analysis is by CE or agarose gels. The same applies for control material for urinary protein electrophoresis.     

Multiphonon vibrations at high angular momentum in 182 Os

Evidence is presented for multiphonon excitations based on a high-spin (25 Planck) intrinsic state in the deformed nucleus 182 Os. Angular momentum generation by this mode competes with collective rotation. The experimental data are compared with tilted-axis cranking calculations, supporting the vibrational interpretation. However, the lower experimental energies provide evidence that more complex interactions of states are playing a role.     

The platelet as a model for chemical genetics

Chemical genetics is an emerging strategy in chemical biology that promises to bring the power of true genetics to mammalian systems and facilitate the transfer of biological discoveries to therapeutics. The platelet is an anucleate cell with several features that render it suitable for chemical genetic analysis. This review addresses the benefits and challenges of chemical genetics using platelets as a model system.