RESUMEN

In the paper we comment on [Rudiger and Shalybkov (RS), Phys. Rev. E 69, 016303 (2004)], the instability of the Taylor-Couette flow interacting with a homogeneous background field subject to the Hall effect is studied. We correct a falsely generalizing interpretation of results presented there which could be taken to disprove the existence of the Hall-drift-induced magnetic instability described in Rheinhardt and Geppert, Phys. Rev. Lett. 88, 101103 (2002). It is shown that, in contrast to what is suggested by RS, no additional shear flow is necessary to enable such an instability with a nonpotential magnetic background field, whereas for a curl-free one it is. In the latter case, the instabilities found in RS in situations where neither a hydrodynamic nor a magnetorotational instability exists are demonstrated to be most likely magnetic instead of magnetohydrodynamic. Further, some minor inaccuracies are clarified.

RESUMEN

BACKGROUND AND OBJECTIVE: The aim of the project was to document and evaluate the safety of combinations of drugs prescribed during hospitalization, producing a method of quality assurance assessment. PATIENTS/METHODS: The medications of 396 patients already taken at home as well as the drugs given in the hospital during an acute illness were analyzed. Potential drug interactions were detected using a computerized drug-interaction checking system i.e. Micromedex CD-ROM database DRUG-REAX. This program differentiates between contraindicated, major, moderate or minor interactions. RESULTS: No contraindicated combinations of medications were found but in 265 instances (66,9%) potentially relevant ( major or moderate) combinations could be detected. There was a correlation between potentially dangerous drug combinations and the number of coadministered drugs. Despite the detection of a large number of potentially troublesome combinations, no significant clinical problems were observed over at least three days of observation. CONCLUSIONS: The number of potentially relevant drug interactions represents a severe problem in drug prescribing.

Asunto(s)

Fármacos Dermatológicos/efectos adversos , Interacciones Farmacológicas , Prescripciones de Medicamentos , Garantía de la Calidad de Atención de Salud , Sistemas de Registro de Reacción Adversa a Medicamentos/estadística & datos numéricos , Anciano , Contraindicaciones , Fármacos Dermatológicos/administración & dosificación , Quimioterapia Combinada , Femenino , Alemania , Humanos , Masculino , Persona de Mediana Edad , Factores de Riesgo

RESUMEN

In the presence of a strong magnetic field and under conditions as realized in the crust and the superfluid core of neutron stars, the Hall drift dominates the field evolution. We show by a linear analysis that, for a sufficiently strong large-scale background field depending at least quadratically on position in a plane conducting slab, an instability occurs which rapidly generates small-scale fields. Their growth rates depend on the choice of the boundary conditions, increase with the background field strength, and may reach 10(3) times the Ohmic decay rate. The effect of that instability on the rotational and thermal evolution of neutron stars is discussed.

RESUMEN

We confront theoretical models for the rotational, magnetic, and thermal evolution of an ultramagnetized neutron star, or magnetar, with available data on the anomalous X-ray pulsars (AXPs). We argue that, if the AXPs are interpreted as magnetars, their clustering of spin periods between 6 and 12 s (observed at present in this class of objects), their period derivatives, their thermal X-ray luminosities, and the association of two of them with young supernova remnants can only be understood globally if the magnetic field in magnetars decays significantly on a timescale of the order of 104 yr.

RESUMEN

A method is proposed for measuring different energy ranges of x-ray radiation with the same spectrometer crystal employing structural phase transitions. When the crystal temperature is varied beyond the phase transition temperature, the crystal symmetry is altered predictably and reversibly. Thus, with no change in the angle of glancing incidence, the x-ray beam hits in different crystal phases different lattice planes which correspond to different energy ranges. The advantage is that neither large motions nor exchanging the spectrometer crystal is necessary during observations.