This discussion attempts to present a simple explanation of the current theory of error catastrophe and why it does not herald a paradigm shift in antiviral strategy. In the main text of the paper, the workings of a simple model of error catastrophe are examined to demonstrate what actually causes error catastrophe. The Appendix contains a more detailed discussion of the original error threshol...

We study generating functions for the number of permutations on n letters avoiding 132 and an arbitrary permutation τ on k letters, or containing τ exactly once. In several interesting cases the generating function depends only on k and is expressed via Chebyshev polynomials of the second kind. 2000 Mathematics Subject Classification: Primary 05A05, 05A15; Secondary 30B70, 42C05

A graphG = (V,E) is word-representable if there exists a word w over the alphabet V such that letters x and y alternate in w if and only if xy is an edge in E. Word-representable graphs are the main focus in “Words and Graphs” by Kitaev and Lozin. A word w = w1 · · ·wn avoids the pattern 132 if there are no 1 ≤ i1 < i2 < i3 ≤ n such that wi1 < wi3 < wi2. A recently suggested research direction ...

v < va. In the other extreme, when v ˆ 0:4 arcsec, the magnetic ®eld from the magnetar would be negligible, but the inferred ®eld strength can be easily explained as arising from compression of the ambient ®eld by the bow shock. The mean expansion speed of the nebula is 3:5 3 1010d5v4t 2 1 10 cm s 2 1 where t10 is the age of the nebula in units of 10 days. Thus in the limit of v ˆ 0:4 arcsec th...

We study generating functions for the number of involutions of length n avoiding (or containing exactly once) 132 and avoiding (or containing exactly once) an arbitrary permutation τ of length k. In several interesting cases these generating functions depend only on k and can be expressed via Chebyshev polynomials of the second kind. In particular, we show that involutions of length n avoiding ...

likely than nonusers to engage in risky sexual behavior and that they are less likely than nonusers to rely on condoms. In some studies, condom use has been treated as one component of a sexual-risk index, which is then related to substance use. In other research, condom use has been treated as a separate independent variable, which is then related to substance use directly. In this article, we...

This paper developed a methodology based on the catastrophe theory for estimating the rural informatization level in central China, and took evaluation of the rural informatization level among the six provinces of central China as an example to test the effectiveness of the method. Taking data from reference and constructing the hierarchy based on catastrophe progression method, it was calculat...