The Wright-Fisher model of allele dynamics forms the basis for most theoretical and applied research in population genetics. Our understanding of genetic drift, and its role in suppressing the deterministic forces of Darwinian selection has relied on the specific form of sampling inherent to the Wright-Fisher model and its diffusion limit. Here we introduce and analyze a broad class of forward-...

We present a novel method for determining the surface density of protoplanetary disks through consideration of disk ‘dust lines’ which indicate the observed disk radial scale at different observational wavelengths. This method relies on the assumption that the processes of particle growth and drift control the radial scale of the disk at late stages of disk evolution such that the lifetime of t...

Traditional approaches to data mining are based on an assumption that the process that generated or is generating a data stream is static. Although this assumption holds for many applications, it does not hold for many others. Consider systems that build models for identifying important e-mail. Through interaction with and feedback from a user, such a system might determine that particular e-ma...

What is genetic drift? Say you have a population of 5,000 people. That makes 10,000 copies of each gene. Imagine a gene where 3,000 of those copies are of one particular allele or type. In the next generation, there won’t necessarily be exactly 3,000 copies again. There may be 3,050 or 2,960 copies instead. Some gametes get randomly picked out of all the possible gametes that could have been us...

A study of the generation of zonal flows and zonal magnetic fields by finite beta drift waves and kinetic drift-Alfvén waves is presented. The analysis is a generalization of recent investigations of the modulational instability for zonal flow generation by electrostatic drift waves to finite beta drift waves and kinetic drift-Alfvén waves. The drift wave driven unstable zonal flows/fields are ...

Quantifying the importance of random genetic drift in natural populations is central to understanding the potential limits to natural selection. One approach is to estimate the magnitude of heterosis, the increased fitness of progeny derived from crosses between populations relative to crosses within populations caused by the heterozygous masking of deleterious recessive or nearly recessive all...

A widespread phenomenon in moving microorganisms and cells is their ability to reorient themselves depending on changes of concentrations of certain chemical signals. In this paper we discuss kinetic models for chemosensitive movement, which also takes into account evaluations of gradient fields of chemical stimuli which subsequently influence the motion of the respective microbiological specie...

Time stability plays an important role in the applications of scanning probe microscopes (SPMs). Although SPMs integrated with a closed-loop control system could reduce the drift greatly, drift would still exist. The SPM drift in the lateral direction has been well studied, and several measurement methods have also been developed. However, due to coupling of the lateral drift, it is still diffi...

BACKGROUND Patients increasingly use online health communities to exchange health information and peer support. During the progression of health discussions, a change of topic-topic drift-can occur. Topic drift is a frequent phenomenon linked to incoherence and frustration in online communities and other forms of computer-mediated communication. For sensitive topics, such as health, such drift ...

For quantitative study of the sort of random drift due to inbreeding it is de sirable to experiment with segregating genotypes that can be classified without risk of error and with populations that are all of a very small definitely known size. With respect to the first condition, it is much the most satisfactory if all segregat ing genotypes can be distinguished ac curately. This, however, lim...