Integrated Calendar

A flapping insect is a nonlinear dynamical system, strongly coupled to unsteady and complex fluid flows. Furthermore, flying insects are subject to fast-growing mechanical instabilities that must be controlled to enable flight. Hence, similar to balancing a stick on one's fingertip, insect flight is a delicate balancing act made possible only by continuous, fast sensory integration and corrective actions.We focus on open questions in insect flight research that are associated with flight control mechanisms, aerodynamics and stability, sensory integration and energetic optimality. For example, combining mid-air perturbation experiments, 3D tracking methods, and inverse-dynamics simulation, we revealed a new flight control mechanism in mosquitoes, where they use the inertia of their legs for rapid aerial steering based on the conservation of angular momentum. Additionally, we use computational fluid dynamics to understand the inherent flight instability of fruit flies, present theoretical results on the energetic optimality of flapping flight and oscillating systems in general, and demonstrate how insects can fly in total darkness. These findings reveal the intricate interplay of aerodynamics, biomechanics, and sensory feedback that enables the maneuverability and grace of flying insects.FOR THE LATEST UPDATES AND CONTENT ON SOFT MATTER AND BIOLOGICAL PHYSICS AT THE WEIZMANN, VISIT OUR WEBSITE: https://www.bio

Numerous drugs have the ability to alter our perception, cognition, and mood. Some of these compounds, such as ketamine and serotonergic psychedelics, have also shown promise as treatment for mental illnesses. The behavioral effects are often long-lasting, presumably because the drugs act on synapses and dendrites to induce plasticity in the brain. In this talk, I will describe a series of studies from my lab aimed at understanding the mechanism of action of psilocybin, using subcellular-resolution two-photon imaging, in vivo electrophysiology, rabies viral tracing, and other molecular and behavioral approaches in mice. The results provide insights into the drug action of psychedelics on neural circuits.

Chirality or handedness is one of the deepest and most persistent mysteries in the sciences, from the molecular asymmetry of life’s building blocks to the emergence of homochirality in early prebiotic systems. Why is chirality “contagious, ” as when a tiny fraction of chiral dopant induces cholesteric twist in an achiral nematic? What mechanisms can spontaneously break mirror symmetry in systems composed entirely of achiral molecules? These questions lie at the intersection of physics, chemistry, and the origins of life. Using the tools of statistical physics, we explore a mechanism that focuses on the role of intramolecular degrees of freedom, in which achiral molecules switch between degenerate configurations of opposite handedness. Theoretical analysis predicts a phase diagram featuring a spatially segregated cholesteric phase with alternating domains of left- and right-handed chiral twist, alongside racemic nematic and isotropic phases. Our model also demonstrates how chiral molecular fluctuations influence the helical twisting power of dopants in the nematic phase. Monte Carlo simulations validate the predicted phase diagram and reveal pattern formation and coarsening in the segregated cholesteric phase. These results suggest that molecular fluctuations between degenerate chiral configurations may be a common mechanism driving cooperative chiral order in soft materials composed of achiral molecules.FOR THE LATEST UPDATES AND CONTENT ON SOFT MATTER AND BIOLOGICAL PHYSICS AT THE WEIZMANN, VISIT OUR WEBSITE: https://www.bio