Chaos induced coherence in two independent food chains

Coherence evolution of two food web models can be obtained under the stirring effect of chaotic advection. Each food web model sustains a three--level trophic system composed of interacting predators, consumers and vegetation. These populations compete for a common limiting resource in open flows with chaotic advection dynamics. Here we show that two species (the top--predators) of different colonies chaotically advected by a jet--like flow can synchronize their evolution even without migration interaction. The evolution is charaterized as a phase synchronization. The phase differences (determined through the Hilbert transform) of the variables representing those species show a coherent evolution.Comment: 5 pages, 5 eps figures. Accepted for publication in Phys. Rev.

Bayesian Inference in Processing Experimental Data: Principles and Basic Applications

This report introduces general ideas and some basic methods of the Bayesian probability theory applied to physics measurements. Our aim is to make the reader familiar, through examples rather than rigorous formalism, with concepts such as: model comparison (including the automatic Ockham's Razor filter provided by the Bayesian approach); parametric inference; quantification of the uncertainty about the value of physical quantities, also taking into account systematic effects; role of marginalization; posterior characterization; predictive distributions; hierarchical modelling and hyperparameters; Gaussian approximation of the posterior and recovery of conventional methods, especially maximum likelihood and chi-square fits under well defined conditions; conjugate priors, transformation invariance and maximum entropy motivated priors; Monte Carlo estimates of expectation, including a short introduction to Markov Chain Monte Carlo methods.Comment: 40 pages, 2 figures, invited paper for Reports on Progress in Physic

Study of CP Violating Effects in Time Dependent B0(B0ˉ)→D(∗)∓π±B^0(\bar{B^0}) \to D^{(*)\mp}\pi^{\pm} Decays

We report measurements of time dependent decay rates for $B^0(\bar{B}^0) \to D^{(*)\mp}\pi^{\pm}$ decays and extraction of CP violation parameters containing $\phi_3$. Using fully reconstructed $D^{(*)}\pi$ events from a $140 {\rm fb}^{-1}$ data sample collected at the $\Upsilon(4S)$ resonance, we obtain the CP violation parameters for $D^* \pi$ and $D \pi$ decays, $2R_{D^{(*)} \pi} \sin (2\phi_1 + \phi_3 \pm \delta_{D^{(*)} \pi})$, where $R_{D^{(*)} \pi}$ is the ratio of the magnitudes of the doubly-Cabibbo-suppressed and Cabibbo-favoured amplitudes, and $\delta_{D^{(*)} \pi}$ is the strong phase difference between them. Under the assumption of $\delta_{D^{(*)} \pi}$ being close to either 0 or $180^{\circ}$, we obtain $|2R_{D^* \pi} \sin (2\phi_1 + \phi_3)| = 0.060 \pm 0.040(\mathrm{stat}) \pm 0.019(\mathrm{sys})$ and $|2R_{D \pi} \sin (2\phi_1 + \phi_3)| = 0.061 \pm 0.037(\mathrm{stat}) \pm 0.018(\mathrm{sys})$.Comment: 9 pages, 3 figures, Submitted to Physical Review Letter