Mitogen-activated protein kinase (MAPK) cascades can operate as bistable switches residing in either of two different stable states. MAPK cascades are often embedded in positive feedback loops, which are considered to be a prerequisite for bistable behavior. Here we demonstrate that in the absence of any imposed feedback regulation, bistability and hysteresis can arise solely from a distributiv...

Transcriptional positive-feedback loops are widely associated with bistability, characterized by two stable expression states that allow cells to respond to analog signals in a digital manner. Using a synthetic system in budding yeast, we show that positive feedback involving a promoter with multiple transcription factor (TF) binding sites can induce a steady-state bimodal response without coop...

Gene expression in bacteria is traditionally studied from the average behaviour of cells in a population, which has led to the assumption that under a particular set of conditions all cells express genes in an approximately uniform manner. The advent of methods for visualizing gene expression in individual cells reveals, however, that populations of genetically identical bacteria are sometimes ...

Much attention has been paid recently to bistability and switch-like behavior that might be resident in important biochemical reaction networks. There is, in fact, a great deal of subtlety in the relationship between the structure of a reaction network and its capacity to engender bistability. In common physicochemical settings, large classes of extremely complex networks, taken with mass actio...

We study implications of complexity and seasonality in vector-host epidemiological models exhibiting backward bifurcation. Vector-host diseases represent complex infection systems that can vary in the transmission processes and population stages involved in disease progression. Seasonal fluctuations in external forcing factors can also interact in a complex way with internal host factors to gov...

A bimodal distribution of tropical tree cover at intermediate precipitation levels has been presented as evidence of fire-induced bistability. Here we subdivide satellite vegetation data into those from human-unaffected areas and those from regions close to human-cultivated zones. Bimodality is found to be almost absent in the unaffected regions, whereas it is significantly enhanced close to cu...

Quantum optical transition phenomena as the laser threshold or the optical bistability can be described by a mean field approach, in terms of a single order parameter x (the e.m. field) driven by a nonlinear force depending by some control parametersy (e.g., the excitation rate of active atoms in the laser, the density of absorbing atoms or the amplitude of the external field in the optical bis...

Fission yeast G2/M transition is regulated by a biochemical reaction networks which contains four components: Cdc13, Cdc2, Wee1, and Cdc25. This circuit is characterized by the ultrasensitive responses of Wee1 or Cdc25 to Cdc13/Cdc2 activity, and the bistability of Cdc2 activation. Previous work has shown that this bistability is governed by phosphorylation energy. In this article, we developed...

We conducted a theoretical investigation of the optical steady-state behavior in N four-level Y-type atoms driven coherently by a probe laser and a single elliptically polarized field (EPF) bymeans of a unidirectional ring cavity. It was found that the optical bistability can be observed for a wide regime of frequency detuning of the probe field, intensity of the EPF, and the atomic cooperation...

Evidence of modulated dissipative structures with an intrinsic wavelength in a nonlinear optical system devoid of Turing instability is given. They are found in the transverse field distribution of an optical cavity containing a liquid crystal light valve. Their existence is related to a transition from flat to modulated fronts connecting the unstable middle branch of a bistability cycle and ei...