A quick-retrieval high-speed digital framing camera

A new high-speed digital framing camera is described. The design is built around a rotating polygon mirror that provides a framing rate of 24 000 frames/s. The camera electronics digitizes an image into a 32×104 grid of pixels, where the second dimension of the grid can be varied and is determined by the 8 bit computer-aided measurement and control digitizer sampling rate. Available digitizer memory provides for 314 frames at this horizontal resolution. The advantages over other available high-speed framing cameras are (1) low cost of the system provided the digitizers are available, (2) rapid retrieval of a recorded event, and (3) the ease with which the system can be used. Sample results from an application in high-power arc photography are given to illustrate the system's spatial and temporal resolution

Models of Meson-Baryon Reactions in the Nucleon Resonance Region

It is shown that most of the models for analyzing meson-baryon reactions in the nucleon resonance region can be derived from a Hamiltonian formulation of the problem. An extension of the coupled-channel approach to include $\pi\pi N$ channel is briefly described and some preliminary results for the $N^*(1535)$ excitation are presented.Comment: Latex 13 pages; to appear in the Proceedings of Workshop on the Physics of excited nucleons (NSTAR2004), Grenoble (France), March 24-27, 200

Phase control of La2CuO4 in thin-film synthesis

The lanthanum copper oxide, La2CuO4, which is an end member of the prototype high-Tc superconductors (La,Sr)2CuO4 and (La,Ba)2CuO4, crystallizes in the "K2NiF4" structure in high-temperature bulk synthesis. The crystal chemistry, however, predicts that La2CuO4 is at the borderline of the K2NiF4 stability and that it can crystallize in the Nd2CuO4 structure at low synthesis temperatures. In this article we demonstrate that low-temperature thin-film synthesis actually crystallizes La2CuO4 in the Nd2CuO4 structure. We also show that the phase control of "K2NiF4"-type La2CuO4 versus "Nd2CuO4"-type La2CuO4 can be achieved by varying the synthesis temperature and using different substrates.Comment: 4 pages, 5 figures, submitted to PRB, revte

An Isomonodromy Cluster of Two Regular Singularities

We consider a linear $2\times2$ matrix ODE with two coalescing regular singularities. This coalescence is restricted with an isomonodromy condition with respect to the distance between the merging singularities in a way consistent with the ODE. In particular, a zero-distance limit for the ODE exists. The monodromy group of the limiting ODE is calculated in terms of the original one. This coalescing process generates a limit for the corresponding nonlinear systems of isomonodromy deformations. In our main example the latter limit reads as $P_6\to P_5$, where $P_n$ is the $n$-th Painlev\'e equation. We also discuss some general problems which arise while studying the above-mentioned limits for the Painlev\'e equations.Comment: 44 pages, 8 figure

Formation of cosmological mass condensation within a FRW universe: exact general relativistic solutions

Within the framework of an exact general relativistic formulation of gluing manifolds, we consider the problem of matching an inhomogeneous overdense region to a Friedmann-Robertson-Walker background universe in the general spherical symmetric case of pressure-free models. It is shown that, in general, the matching is only possible through a thin shell, a fact ignored in the literature. In addition to this, in subhorizon cases where the matching is possible, an intermediate underdense region will necessarily arise.Comment: 6 page

Step Bunching with Alternation of Structural Parameters

By taking account of the alternation of structural parameters, we study bunching of impermeable steps induced by drift of adatoms on a vicinal face of Si(001). With the alternation of diffusion coefficient, the step bunching occurs irrespective of the direction of the drift if the step distance is large. Like the bunching of permeable steps, the type of large terraces is determined by the drift direction. With step-down drift, step bunches grows faster than those with step-up drift. The ratio of the growth rates is larger than the ratio of the diffusion coefficients. Evaporation of adatoms, which does not cause the step bunching, decreases the difference. If only the alternation of kinetic coefficient is taken into account, the step bunching occurs with step-down drift. In an early stage, the initial fluctuation of the step distance determines the type of large terraces, but in a late stage, the type of large terraces is opposite to the case of alternating diffusion coefficient.Comment: 8pages, 16 figure

Pharmacogenetics of analgesic drugs

• Individual variability in pain perception and differences in the efficacy of analgesic drugs are complex phenomena and are partly genetically predetermined. • Analgesics act in various ways on the peripheral and central pain pathways and are regarded as one of the most valuable but equally dangerous groups of medications. • While pharmacokinetic properties of drugs, metabolism in particular, have been scrutinised by genotype–phenotype correlation studies, the clinical significance of inherited variants in genes governing pharmacodynamics of analgesics remains largely unexplored (apart from the µ-opioid receptor). • Lack of replication of the findings from one study to another makes meaningful personalised analgesic regime still a distant future. • This narrative review will focus on findings related to pharmacogenetics of commonly used analgesic medications and highlight authors’ views on future clinical implications of pharmacogenetics in the context of pharmacological treatment of chronic pain

Influence of non-local exchange on RKKY interactions in III-V diluted magnetic semiconductors

The RKKY interaction between substitutional Mn local moments in GaAs is both spin-direction-dependent and spatially anisotropic. In this Letter we address the strength of these anisotropies using a semi-phenomenological tight-binding model which treats the hybridization between Mn d-orbitals and As p-orbitals perturbatively and accounts realistically for the non-local exchange interaction between their spins. We show that exchange non-locality, valence-band spin-orbit coupling, and band-structure anisotropy all play a role in determining the strength of both effects. We use these results to estimate the degree of ground-state magnetization suppression due to frustrating interactions between randomly located Mn ions.Comment: 4 pages RevTeX, 2 figures included, v2: replacement because of font proble