Savanna models that are based on recurrent disturbances such as fire result in nonequilibrium savannas, but these models rarely incorporate vegetation feedbacks on fire frequency or include more than two states (grasses and trees). We develop a disturbance model that includes vegetation-fire feedbacks, using a system of differential equations to represent three main components of savannas: gras...

Species experience both internal feedbacks with endogenous factors such as trait evolution and external feedbacks with exogenous factors such as weather. These feedbacks can play an important role in determining whether populations persist or communities of species coexist. To provide a general mathematical framework for studying these effects, we develop a theorem for coexistence for ecologica...

Positive feedbacks between vegetation and fire disturbance may lead to nonlinear ecosystem responses to variation in fire regime. We used a cellular automaton model of fire|vegetation dynamics based on pine savanna communities to explore the potential for fire|vegetation feedbacks to lead to ecological thresholds and abrupt transitions between alternate ecosystem states. We show that (i) ecosys...

The mechanisms of interdecadal changes of El NifioSouthern Oscillation (ENSO) modes are examined through an eigen analysis of a simple coupled ocean-atmosphere model. It is shown that the observed interdecadal climate shift can effectively modify the strength of two major coupled feedbacks for the ENSO mode, namely, the zonal advection and thermocline feedbacks. These modifications lead to quan...

The impacts of air-sea interactions on the representation of tropical precipitation extremes are investigated using an atmosphere-ocean-mixed-layer coupled model. The coupled model is compared to two atmosphere-only simulations driven by the coupled-model sea-surface temperatures (SSTs): one with 31 day running means (31 d), the other with a repeating mean annual cycle. This allows separation o...

The development of adaptive observer techniques for nonlinear systems in the output canonical form is proposed applying additional impulsive feedbacks in the observer equations. The stability of new impulsive adaptive observers is investigated. It is shown that under some conditions the proposed impulsive feedbacks can improve the rate of the observer convergence or relax the requirement on per...

The recognition of feedbacks between plants and their physical environment is important in biogeography. At alpine treeline, positive feedbacks for trees versus tundra include warming the canopy via lower albedo, increasing nutrients and water by increasing local atmospheric deposition, and reducing transpiration and abrasion by slowing wind; negative feedbacks include shading and cooler soil. ...

Objetivando el desarrollo tecnológico como soporte al estudio técnico-individual de dirección para alumnos con discapacidad visual, en este abordaje, es expuesta a secuencia pruebas y sus resultados, la recolecta los requisitos necesarios constitución programación del prototipo Maestro v0.1 — os feedbacks háptico auditivo. Por lo tanto, considerándolos elementos primordiales provocar acción cor...