Self-oscillating chemical reactions that undergo reaction–diffusion (RD) phenomena have shown great potential for designing stimuli-responsive materials. Belousov–Zhabotinsky (BZ) reactions are one such class of reactions that exhibit nonlinear chemical oscillations due to redox cycles of the metal-ion catalyst by virtue of Hopf bifurcation. Using bifurcation analyses, here we investigate the BZ reactions, catalyzed by 0D–2D catalytic nanomats and bare nanosheets, which are known to exhibit enhanced dynamic response due to catalysts’ heterogeneity. Specifically, we incorporate the nanocatalysts’ activity in the kinetic model of the BZ reactions and, subsequently, use catalysts’ activity as the bifurcation parameter for analyses. By computing higher-order Lyapunov and frequency coefficients, we have revealed new oscillatory regimes in the bifurcation diagram, including re-entrant regions where sustained oscillations are unexpectedly suppressed, even with high catalytic activity. In addition, we also calculate the amplitude and frequency of BZ oscillations in each of these regions as a function of nanocatalysts’ activity. We believe that our current findings can be used to harness the nonlinearity of RD-based dynamical systems to provide unique functionalities to active stimuli-response systems.

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This study examines the relationship between morphological traits related to body size and fin morphology and the environment in snow trout, Schizothorax richardsonii, a widespread species from the upper Ganga river basin, India. Three body shape traits (index of compression, index of trunk shape and relative body depth) and three fin traits (dorsal fin relative area, pectoral fin relative area and pectoral fin aspect ratio) were related to five environmental variables (water temperature, water flow, depth, conductivity and substrate diversity) across eight study streams. Water temperature, conductivity and substrate diversity were highly variable across the sampled sites. There was a significant negative correlation (r = -0.676) between composite morphological traits (principal components) related to body size and fin morphology. Furthermore, both body size and fin morphology were strongly correlated (r = 0.861 and r = -0.845 respectively) with composite environmental variables (water temperature, conductivity and substrate diversity) across sites. These findings suggest that the morphological traits of fish populations residing across environmental gradients are adapted to different habitats.