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[en] In the above paper, the authors proposed a search algorithm for finding simple chaotic systems with quadratic nonlinearities which have the unusual feature of having a line equilibrium and introduced nine novel chaotic flows. However, the equations of 4th–9th chaotic flows were incorrectly given. In this letter, the correct equations are presented for the future usage of these line equilibrium chaotic flows

[en] Using the notion of topological pressure for non-compact sets, we prove a relation for two topological pressures with a factor map. We also provide an application in symbolic dynamics and conformal repellers. These results are generalized to the cases of BS-dimensions

[en] When stimulated by a point source of cyclic AMP, a starved amoeba of Dictyostelium discoideum responds by putting out a hollow balloon-like membrane extension followed by a pseudopod. The effect of the stimulus is to influence the position where either of these protrusions is made on the cell rather than to cause them to be made. Because the pseudopod forms perpendicular to the cell surface, its location is a measure of the precision with which the cell can locate the cAMP source. Cells beyond 1 h of starvation respond non-randomly with a precision that improves steadily thereafter. A cell that is starved for 1–2 h can locate the source accurately 43% of the time; and if starved for 6–7 h, 87% of the time. The response always has a high scatter; population-level heterogeneity reflects stochasticity in single cell behaviour. From the angular distribution of the response its maximum information content is estimated to be 2–3 bits. In summary, we quantitatively demonstrate the stochastic nature of the directional response and the increase in its accuracy over time

[en] Organisms use biological timing mechanisms to synchronise life-history transitions to annual environmental cycles. For species living outside the equatorial zone, day length change is a widely used external cue for seasonal biological clocks. This paper builds on recent developments in understanding the neuroanatomical basis of day length measurement (photoperiodism) in mammals, by taking a modelling approach to the molecular readout mechanism. We find that, while a circadian clock based system can drive day length dependent changes in the amplitude of a seasonal output (in this case production of the hormone thyrotrophin), the inclusion of a positive feedback based amplifier mechanism generates photoperiodic transitions that more closely match experimental observations. The analogies between our model and those proposed for boundary generation in developmental biology are briefly discussed