The problem of generating random bits from an arbitrary biased coin, dating back to von Neumann’s 1951 work, has been extensively studied. Specifically, given a fixed number of biased coin tosses with unknown probability, it is well known how to generate random bits with an asymptotically optimal efficiency. In this paper we address two basic questions related to the generation of random bits. ...

I present here evidence of remarkable local changes in GC/AT substitution biases and in crossover frequencies on Drosophila chromosomes. The substitution pattern at 10 loci in the telomeric region of the X chromosome was studied for four species of the Drosophila melanogaster species subgroup. Drosophila orena and Drosophila erecta are clearly the most closely related species pair (the erecta c...

Fast evolving regions of many metazoan genomes show a bias toward substitutions that change weak (A,T) into strong (G,C) base pairs. Single-nucleotide polymorphisms (SNPs) do not share this pattern, suggesting that it results from biased fixation rather than biased mutation. Supporting this hypothesis, analyses of polymorphism in specific regions of the human genome have identified a positive c...

We present a general approach connecting biased Maker-Breaker games and problems about local resilience in random graphs. We utilize this approach to prove new results and also to derive some known results about biased Maker-Breaker games. In particular, we show that for b = Θ( n lnn), playing a (1 : b) game on E(Kn), Maker can build a graph which contains copies of all spanning trees having ma...

We study the conductance of chaotic or disordered wires in a situation where equilibrium transport decomposes into biased diffusion and a countermoving regular current. A possible realization is a semiconductor nanostructure with a transversal magnetic field and suitably patterned surfaces. We find a nontrivial dependence of the conductance on the wire length. It differs qualitatively from Ohm'...

We quantify fundamental bias-variance tradeoffs for the image reconstruction problem in radio-pharmaceutical tomography using Cramer-Rao (CR) bound analysis. The image reconstruction problem is very often biased and the classical or the unbiased CR bound on the mean square error performance of the estimator can not be used. We use a recently developed ‘uniform’ CR bound which a p plies to biase...

Evolutionary algorithms as general randomized search heuristics typically perform a random search that is biased only by the fitness of the search points encountered. In practical applications the use of biased variation operators suggested by problem-specific knowledge may speed-up the search considerably. Problems defined over bit strings of finite length often have the property that good sol...

We consider the detection of biased information sources in the ubiquitous codedivision multiple-access (CDMA) scheme. We propose a simple modification to both the popular single-user matched-filter detector and a recently introduced near-optimal message-passing-based multiuser detector. This modification allows for detecting modulated biased sources directly with no need for source coding. Anal...

Hypotheses for the adaptive significance of extreme female-biased sexual size dimorphism (SSD) generally assume that in dimorphic species males rarely interfere with each other. Here we provide the first multivariate examination of sexual selection because of male-male competition over access to females in a species with 'dwarf' males, the orb-weaving spider Argiope aurantia. Male A. aurantia t...

This study was intended to find out any possible effect of topic bias on the writing proficiency of Iranian extrovert/introvert EFL learners at high/low writing proficiency levels. One hundred participants chosen from among 150 adult language learners on the basis of their personality type (extrovert/introvert) and writing proficiency (high/low) took part in this study. They were arranged into ...