Sustained plankton blooms under open chaotic flows

We consider a predator-prey model of planktonic population dynamics, of excitable character, living in an open and chaotic fluid flow, i.e., a state of fluid motion in which fluid trajectories are unbounded but a chaotic region exists that is restricted to a localized area. Despite that excitability is a transient phenomenon and that fluid trajectories are continuously leaving the system, there is a regime of parameters where the excitation remains permanently in the system, given rise to a persistent plankton bloom. This regime is reached when the time scales associated to fluid stirring become slower than the ones associated to biological growth.Comment: 14 pages, 3 figure

Non-Unitarity vs sterile neutrinos at DUNE

Neutrino masses are one of the most promising open windows to physics beyond the Standard Model (SM). Several extensions of the SM which accommodate neutrino masses require the addition of right-handed neutrinos to its particle content. These extra fermions will either be kinematically accessible (sterile neutrinos) or not (deviations from Unitarity of the PMNS matrix) but at some point they will impact neutrino oscillation searches. We explore the differences and similitudes between the two cases and compare their present bounds with the expected sensitivities of DUNE. We conclude that Non-Unitarity (NU) effects are too constrained to impact present or near future neutrino oscillation facilities but that sterile neutrinos can play an important role at long baseline experiments.Comment: Talk and poster presented at NuPhys2016 (London, 12-14 December 2016). 8 pages, LaTeX, 4 eps figures. Based on arXiv:1609.0863

Information Gap Activities: A Standards-Based Strategy for Promoting Oral Proficiency in a Thematic Context

This article demonstrates how the sustained use of standards-driven information gap activities (IGAs) supports and enhances the development of speaking skills. In the first section, we define the IGA. We then discuss recent research showing how IGAs promote focused student-student interactions. In the third section we provide a blueprint for implementing the IGA in a standards-based thematic context. We conclude with content-based models from a thematic unit on Argentina that are appropriate for both secondary and post-secondary classrooms