We study the 2-D Helmholtz equation in perturbed stratified media, allowing the existence of guided waves. Our assumptions on the perturbing and source terms are not too restrictive. We prove two results. Firstly, we introduce a Sommerfeld-Rellich radiation condition and prove the uniqueness of the solution for the studied equation. Then, by careful asymptotic estimates, we prove the existence ...

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Rahman, l.r.c p. and lf.p s. (Glas.), Civil Surgeon, Burma. This Manual 1ms been compiled by Dr. Rahman to explain the methods of vaccination and its superiority to the dangerous practice of inoculation against small-pox. We entirely agree with him that a systematic training is necessary in the method of vaccination. The first chapter deala with the mortality from small-pox, its infectivity, it...

Determining the upper treeline is certainly one of the most interesting research challenges in comparative high mountain research. Careful compilations (Hermes 1955; von Wissmann 1961; Schickhoff 2005) have documented that the highest treelines in the northern hemisphere are found on the eastern declivity of the Tibetan Highlands. However, regional and global synopses of upper treeline altitude...

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