منابع مشابه
Periodic chirality transformations propagating on bacterial flagella.
When a helical bacterial flagellum, clamped at one end, is placed in an external flow, it has been observed that regions of the flagellum transform to the opposite chirality, and travel as pulses down the length of the filament, the process repeating periodically [H. Hotani, J. Mol. Biol. 156, 791 (1982)]]. We propose a theory for this phenomenon based on a treatment of the flagellum as an elas...
متن کاملQuasi-periodic transformations of nonlocal spatial solitons.
We study quasi-periodic transformations between nonlocal spatial solitons of different symmetries triggered by modulational instability and resembling a self-induced mode converter. Transformation dynamics of solitons with zero angular momentum, e.g. the quadrupole-type soliton, reveal the equidistant spectrum of spatial field oscillations typical for the breather-type solutions. In contrast, t...
متن کاملSome Remarks on Almost Periodic Transformations
1. Recurrent and almost periodic transformations. Notations. Let ƒ be a continuous mapping (not necessarily a homeomorphism) of a topological space X in itself (that is, f(X)QX). We say that ƒ is recurrent a t a point # £ X , or that x is recurrent under ƒ, if, given any neighbourhood U(x) of x, there exist infinitely many positive integers n for which f(x)ÇE.U(x). (This definition is equivalen...
متن کاملIDEMPOTENT n-PERMUTABLE VARIETIES
One of the important classes of varieties identified in tame congruence theory is the class of varieties which are n-permutable for some n. In this paper we prove two results: (1) For every n > 1 there is a polynomial-time algorithm which, given a finite idempotent algebra A in a finite language, determines whether the variety generated by A is n-permutable; (2) A variety is n-permutable for so...
متن کاملCyclically permutable codes
Brevity is the soul of wit. William Shakespeare A cyclically permutable code is a set of codewords having the property that no codeword is a cyclic shift of another codeword. We study the problem of constructing cyclically permutable codes of large size and low correlation. Cyclically permutable codes are used in code-division multiple-access systems realized by e.g. direct-sequence modulation ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1944
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.30.5.105