标题： 可压缩流中的群体遗传学 显示英文标题

标题： Population genetics in compressible flows

摘要： 我们研究由可压缩速度场驱动的两种生物物种之间的竞争。个体被当作离散的拉格朗日粒子处理，它们以依赖于密度的方式繁殖或死亡。在没有速度场和适应性优势的情况下，数量波动导致典型的随机费舍尔方程的粗化动力学。然后我们研究了三种可压缩对流场的例子：湍流的壳模型、正弦速度场和线性速度汇。在所有情况下，对流导致固定时间显著下降，以及全球承载能力大幅减少。尽管在汇聚区局部化，一种物种比在充分混合种群中更快地灭绝。对于弱谐波势，可以发现固定时间的双峰分布。在这种情况下，寿命较长的状态是具有单个边界的分离配置，其位置取决于适应性优势。 显示英文摘要

摘要： We study competition between two biological species advected by a compressible velocity field. Individuals are treated as discrete Lagrangian particles that reproduce or die in a density-dependent fashion. In the absence of a velocity field and fitness advantage, number fluctuations lead to a coarsening dynamics typical of the stochastic Fisher equation. We then study three examples of compressible advecting fields: a shell model of turbulence, a sinusoidal velocity field and a linear velocity sink. In all cases, advection leads to a striking drop in the fixation time, as well as a large reduction in the global carrying capacity. Despite localization on convergence zones, one species goes extinct much more rapidly than in well-mixed populations. For a weak harmonic potential, one finds a bimodal distribution of fixation times. The long-lived states in this case are demixed configurations with a single boundary, whose location depends on the fitness advantage.