What is moving in silica at 1 K? A computer study of the low-temperature anomalies

Though the existence of two-level systems (TLS) is widely accepted to explain low-temperature anomalies in many physical observables, knowledge about their properties is very rare. For silica, which is one of the prototype glass-forming systems, we elucidate the properties of the TLS via computer simulations by applying a systematic search algorithm. We get specific information in the configuration space, i.e., about relevant energy scales, the absolute number of TLS, and electric dipole moments. Furthermore, important insight about the real-space realization of the TLS can be obtained. Comparison with experimental observations is included.     

Uniqueness of equilibrium points in bimatrix games

Bimatrix games are constructed having a given pair (x, y) as the unique equilibrium point within the class of all mixed strategy pairs whose nonzero components are the same as (resp., among) those of (x, y). In each case, necessary and sufficient conditions on (x, y) for the existence of such a game are obtained. All games having the first property are constructed. The work extends and complements recent (separate) works ofMillham [1972],Raghavan [1970] and the author. The methods and results are valid in the context of any ordered field.     

Additive Schwarz method for the p-version of the boundary element method for the single layer potential operator on a plane screen

Summary. We analyze an additive Schwarz preconditioner for the p-version of the boundary element method for the single layer potential operator on a plane screen in the three-dimensional Euclidean space. We decompose the ansatz space, which consists of piecewise polynomials of degree p on a mesh of size h, by introducing a coarse mesh of size . After subtraction of the coarse subspace of piecewise constant functions on the coarse mesh this results in local subspaces of piecewise polynomials living only on elements of size H. This decomposition yields a preconditioner which bounds the spectral condition number of the stiffness matrix by . Numerical results supporting the theory are presented. Received August 15, 1998 / Revised version received November 11, 1999 / Published online December 19, 2000     

The Adjustable Laryngeal Implant

An adjustable laryngeal implant made of titanium has been developed for the treatment of unilateral vocal fold paralysis. The implant includes three parts: a plate that allows fixation to the thyroid cartilage, a block of titanium which includes the adjustable part, and a micrometric screw in the middle of the lateral side of the block, which moves the adjustable part. Precise medialization is accomplished by regulating the screw which also permits easy secondary adjustments, if needed in the future. This retrospective study assesses clinical outcomes of medialization laryngoplasty with the titanium adjustable implant, in patients with unilateral vocal fold paralysis. This study has the limitations of a retrospective study. However, preliminary results are encouraging. Analysis of subjective responses confirmed marked improvement in laryngeal function, speech, and swallowing. Objective voice analysis confirmed improvement in the aerodynamic measures. The adjustable laryngeal implant has many advantages including: precise medialization, ease of secondary adjustment, and preseveration of the mucosal wave. This implant is biocompatible, no migration is possible (it is fixed to the cartilage) and no extrusion of the implant has occurred. Titanium is magnetic resonance imaging (MRI)-safe.     

I. The properties of hot Ca-like fragments from the 40Ca + 40Ca reaction at 35AMeV

The creation of hot Ca-like fragments was investigated in the ⁴⁰Ca + ⁴⁰Ca reaction at 35 AMeV. Using the AMPHORA 4π detector system, the primary projectile-like fragment was reconstructed and its properties were determined. Both primary and secondary distributions are compared with the predictions of a Monte Carlo code describing a heavy-ion collision as a two-step process. Some of the nucleons which are identified as participants in the first step are transferred in the second step to these final states, which correspond on the average to the maximum value of entropy (thermodynamic probability). The model allows for competition between mean-field effects and nucleon-nucleon interactions in the overlap zone of the interacting nuclei. The analysis presented here suggests a thermalized source picture of the decay of the projectile-like fragment. The validity of the reconstruction procedure for projectile-like fragments is discussed. Received: 12 March 2001 / Accepted: 20 June 2001     

On the equivalence of fractional-order Sobolev semi-norms

We present various results on the equivalence and mapping properties under affine transformations of fractional-order Sobolev norms and semi-norms of orders between zero and one. Main results are mutual estimates of the three semi-norms of Sobolev–Slobodeckij, interpolation and quotient space types. In particular, we show that the former two are uniformly equivalent under affine mappings that ensure shape regularity of the domains under consideration.     

Influence of irrigation-water salinity on lipids of <Emphasis Type="Italic">Crambe abyssinica</Emphasis> seeds

Lipids of Crambe abyssinica Hochst (Brassicaceae) seeds grown in hothouses in Israel and in the open in Uzbekistan in soil imported from the Aral Sea region were studied. It was found that the seed oil content decreased as the irrigation-water salinity increased. The content of total unsaturated fatty acids of neutral lipids was in the range 91.31–94.81%; of polar lipids, 69.59–83.78%.     

An iterative substructuring method for the p-version of the boundary element method for hypersingular integral operators in three dimensions

Summary. We study preconditioners for the -version of the boundary element method for hypersingular integral equations in three dimensions. The preconditioners are based on iterative substructuring of the underlying ansatz spaces which are constructed by using discretely harmonic basis functions. We consider a so-called wire basket preconditioner and a non-overlapping additive Schwarz method based on the complete natural splitting, i.e. with respect to the nodal, edge and interior functions, as well as an almost diagonal preconditioner. In any case we add the space of piecewise bilinear functions which eliminate the dependence of the condition numbers on the mesh size. For all these methods we prove that the resulting condition numbers are bounded by . Here, is the polynomial degree of the ansatz functions and is a constant which is independent of and the mesh size of the underlying boundary element mesh. Numerical experiments supporting these results are reported. Received July 8, 1996 / Revised version received January 8, 1997     

Intrasubject variability of objective voice measures

Recent advances in the diagnosis and treatment of voice disorders necessitate the need for accurate and reliable objective voice measurements. There are many instruments commonly used to analyze voice data. Many, if not most, of these instruments have not been adequately tested for reliability or consistency. This study evaluates the intrasubject variability of the objective voice measurements from two commonly used voice analysis instruments. The study also presents data correlating subjective mood states, room temperatures, sleep times of the subject, time since last meal, and hydration levels to the various acoustic measures. Several weak but significant correlations were obtained and are discussed. Guidelines for the appropriate use of these instruments are described.     

Buchbesprechungen

Ohne Zusammenfassung