Feedbacks are widely considered to be the largest source of uncertainty in determining the sensitivity of the climate system to increasing anthropogenic greenhouse gas concentrations, yet the ability to diagnose them from observations has remained controversial. Here a simple model is used to demonstrate that any nonfeedback source of top-of-atmosphere radiative flux variations can cause temper...

Network tomography is a process by which internal characteristics of a network are inferred from “external” end-to-end measurements. To ensure that the inferred internal characteristics are sound and trustworthy, it is essential to verify the integrity of data collected from external measurements. In this paper, we present an algorithm which can verify the integrity of data collected from end-t...

We consider a class of output feedback stabilization problems for chemostats with two species. We design dilution rate feedbacks that stabilize a componentwise positive equilibrium. Our feedbacks only depend on the sum of the species levels. The novelty of our treatment is in our dropping the usual condition on the relative sizes of the growth yield constants.

Given a pair of matrices representing a controllable linear system, its equivalence classes by the single or combined action of feedbacks, change of state and input variables, as well as their intersection are studied. In particular, it is proved that they are differentiable manifolds and their dimensions are computed. Some remarks concerning the effect of different kinds of feedbacks are derived.

math.RT/9808098 This short note is devoted to a second quantization of a classical picture described in [1]. 1.1. Interactive games and intention fields. Definition 1 [1]. An interactive system (with n interactive controls) is a control system with n independent controls coupled with unknown or incompletely known feedbacks (the feedbacks, which are called the behavioral reactions, as well as th...

Feedbacks determine the efficiency with which the climate system comes back into equilibrium in response to a radiative perturbation. Although feedbacks are integrated quantities, the processes from which they arise have rich spatial structures that alter the distribution of top of atmosphere (TOA) net radiation. Here, the authors investigate the implications of the structure of climate feedbac...

The IPCC Fourth Assessment Report (AR4) assessed a range of scenarios of future greenhouse gas emissions without policies to specifically reduce emissions, and concluded that these would lead to an increase in global mean temperatures of between 1.4°C and 6.9°C by the end of the 21st Century, relative to pre-industrial. While much political attention is focussed on the potential for global warm...

We examine in detail how epidemiological feedbacks combine with costs and benefits to determine the evolution of resistance by systematically analysing continuously stable strategies (CSS) for different host-parasite frameworks. The mode of resistance (innate versus acquired), the nature of the host (i.e. life-history and immunological memory) and the nature of the disease (effects on fertility...

Terrestrial vegetation influences climate by modifying the radiative-, momentum-, and hydrologicbalance. This paper contributes to the ongoing debate on the question whether positive biogeophysical feedbacks between vegetation and climate may lead to multiple equilibria in vegetation and climate and consequent abrupt regime shifts. Several modelling studies argue that vegetation-climate feedbac...

BACKGROUND Biological invasions are fundamentally biogeographic processes that occur over large spatial scales. Interactions with soil microbes can have strong impacts on plant invasions, but how these interactions vary among areas where introduced species are highly invasive vs. naturalized is still unknown. In this study, we examined biogeographic variation in plant-soil microbe interactions ...