More ergodic billiards with an infinite cusp

In a previous paper (nlin.CD/0107041) the following class of billiards was studied: For $f: [0, +\infty) \longrightarrow (0, +\infty)$ convex, sufficiently smooth, and vanishing at infinity, let the billiard table be defined by $Q$, the planar domain delimited by the positive $x$-semiaxis, the positive $y$-semiaxis, and the graph of $f$. For a large class of $f$ we proved that the billiard map was hyperbolic. Furthermore we gave an example of a family of $f$ that makes this map ergodic. Here we extend the latter result to a much wider class of functions.Comment: 13 pages, 4 figure

Retranslation of humour as a positive intercultural communication strategy

Humorous discourse is a positive communication strategy, which contributes to the success of intercultural encounters. On the other hand, wrong interpretation of humorous culture-specific meanings can be a cause of communication failures. The present paper analyses five translations of I. Ilf and E. Petrov's books The Twelve Chairs and The Golden Calf from Russian into English. The study shows that the key factors which influence the construction of cultural meanings include: background knowledge, presuppositions, imagery, evaluation, emotional perception, cultural context, connection with precedent concepts and texts, and intertextuality. The treatment of cultural meanings also depends on the historical period when the translation is done and the political views of the translator

Escape Orbits for Non-Compact Flat Billiards

It is proven that, under some conditions on $f$, the non-compact flat billiard $\Omega = \{ (x,y) \in \R_0^{+} \times \R_0^{+};\ 0\le y \le f(x) \}$ has no orbits going {\em directly} to $+\infty$. The relevance of such sufficient conditions is discussed.Comment: 9 pages, LaTeX, 3 postscript figures available at http://www.princeton.edu/~marco/papers/ . Minor changes since previously posted version. Submitted to 'Chaos

Friedlander-Keller ray expansions and scalar wave reflection at canonically-perturbed boundaries

This paper concerns the reflection of high-frequency, monochromatic linear waves of wavenumber k (>>1) from smooth boundaries which are O (k-1/2) perturbations away from either a specified near-planar boundary or else from a given smooth, two-dimensional curve of general O(1) curvature. For each class of perturbed boundary, we will consider separately plane and cylindrical wave incidence, with general amplitude profiles of each type of incident field. This interfacial perturbation scaling is canonical in the sense that a ray approach requires a modification to the standard WKBJ 'ray ansatz' which, in turn, leads to a leading-order amplitude (or 'transport') equation which includes an extra term absent in a standard application of the geometrical theory of diffraction ('GTD'). This extra term is unique to this scaling, and the afore-mentioned modification that is required is an application of a generalised type of ray expansion first posed by F G Friedlander and J B Keller [1]

Nonlinear wave interactions in quantum magnetoplasmas

Nonlinear interactions involving electrostatic upper-hybrid (UH), ion-cyclotron (IC), lower-hybrid (LH), and Alfven waves in quantum magnetoplasmas are considered. For this purpose, the quantum hydrodynamical equations are used to derive the governing equations for nonlinearly coupled UH, IC, LH, and Alfven waves. The equations are then Fourier analyzed to obtain nonlinear dispersion relations, which admit both decay and modulational instabilities of the UH waves at quantum scales. The growth rates of the instabilities are presented. They can be useful in applications of our work to diagnostics in laboratory and astrophysical settings.Comment: 15 pages, to appear in Physics of Plasma

Velocity of signal in attractive potential and propagation of light in gravitational field

The propagation of a massless field in attractive and repulsive potentials is considered. It is shown that though the group velocity in such potentials can be larger than one, the wave front propagates with the speed of light. A larger-than-one group velocity leads only to a strong deformation of the wave packet. The results obtained are applied to the light propagation in a gravitational field. An erroneous assertion concerning the last problem, recently made in the literature, is refuted.Comment: 6 pages, latex twic

REFUSAL TO COMMUNICATE AS A POSITIVE AND NEGATIVE COMMUNICATION STRATEGY

The paper has an overall focus on the refusal to communicate, which naïve language users would often interpret as “zero communication”. This aspect of human interaction has not yet been thoroughly investigated, which accounts for the novelty of the research. The paper analyses reasons for the refusal to communicate, its types, strategies, positive and negative effects, as well as verbal and nonverbal ways of its expression. The study uses a mixed-method research design based on observation, discourse analysis and method of introspection. The material of the research includes 389 acts of refusal to communicate selected from real-life or Internet conversations, fiction of the late 20th – early 21st centuries, and films in English and in Russian. All the communicative acts are investigated along the following lines: a) reasons; b) types; c) communication strategies; d) functions and e) forms of linguistic expression of refusal to communicate. We identify regularities and classify our data within each of the devised categories. The paper argues that refusal to communicate, which in fact manifests the intention to terminate communication, is part and parcel of human interaction possessing strong pragmatic, functional and emotional value. Though it is generally seen as a negative communication strategy, this study shows that under certain circumstances it can also have a positive effect on the outcome of interaction

The comparative analysis of statistics, based on the likelihood ratio criterion, in the automated annotation problem

<p>Abstract</p> <p>Background</p> <p>This paper discusses the problem of automated annotation. It is a continuation of the previous work on the A⁴-algorithm (Adaptive algorithm of automated annotation) developed by Leontovich and others.</p> <p>Results</p> <p>A number of new statistics for the automated annotation of biological sequences is introduced. All these statistics are based on the likelihood ratio criterion.</p> <p>Conclusion</p> <p>Some of the statistics yield a prediction quality that is significantly higher (up to 1.5 times higher) in comparison with the results obtained with the A⁴-procedure.</p