Sorting by reversals is an important problem in inferring the evolutionary relationship between two genomes. The problem of sorting unsigned permutation has been proven to be NP-hard. The best guaranteed error bounded is the 3/2approximation algorithm. However, the problem of sorting signed permutation can be solved easily. Fast algorithms have been developed both for finding the sorting sequen...

The relative magnitude of time-dispersion in laser-tissue interactions is proportional to the ratio of the radial width of the pulse to its temporal width and to the group velocity dispersion. The dependence of time dispersion e ects on its sign and magnitude is discussed.

This paper presents the concept of leading-one prediction (LOP) used in most high-speed floating-point adders in greater detail and describes two existing implementations. The first one is similar to that used in the TBM RS /GO00 processor. The second is a distributed version of the first, consuming less hardware when multiple patterns need to be detected. We show how to modify these circuits f...

Feedbacks are widely considered to be the largest source of uncertainty in determining the sensitivity of the climate system to increasing anthropogenic greenhouse gas concentrations, yet the ability to diagnose them from observations has remained controversial. Here a simple model is used to demonstrate that any nonfeedback source of top-of-atmosphere radiative flux variations can cause temper...

Abstract Many stochastic systems in physics and biology are investigated by recording the two-dimensional (2D) positions of a moving test particle in regular time intervals. The resulting sample trajectories are then used to induce the properties of the underlying stochastic process. Often, it can be assumed a priori that the underlying discrete-time random walk model is independent from absolu...

We report an ab initio study of the interlayer exchange coupling in Fe/c-FeSi/Fe sandwiches and Fe/c-FeSi multilayers. We perform several structural studies, which show the stability of the CsCl arrangement seen experimentally for the spacer. We study the effect of pinholes, interface roughness, or structural misconfigurations of the spacer on the sign and magnitude of the exchange constant J. ...

Despite much progress, many questions remain regarding the potential dynamic coupling between atmospheric and lithospheric processes in the long-term evolution of mountain belts. As a complement to recent efforts to discover the interrelationships among climate, topography, erosion, and rock deformation under conditions of mass-flux steady state, we explore orogen response to changes in climate...

We investigate whether the volatility risk premium is negative by examining the statistical properties of delta-hedged option portfolios (buy the option and hedge with stock). Within a stochastic volatility framework, we demonstrate a correspondence between the sign and magnitude of the volatility risk premium and the mean delta-hedged portfolio returns. Using a sample of S&P 500 index options,...

Darwin's classic image of a 'tangled bank' of interdependencies among species has long suggested the difficulty of predicting how the loss of one species alters the abundance of others 1. We show that for dynamical models of realistically structured ecological networks in which pair-wise consumer-resource interactions scale according to allometric ¾ power rules suggested by metabolic theory 2,3...

By a quasi-permutation matrix we mean a square matrix over the complex field C with non-negative integral trace. Thus every permutation matrix over C is a quasipermutation matrix. For a given finite group G, let p(G) denote the minimal degree of a faithful permutation representation of G (or of a faithful representation of G by permutation matrices), let q(G) denote the minimal degree of a fai...