לוח שנה משולב

The lecture presents recent results obtained in the laboratory of Prof. Oleg Vasyutinskii in the Ioffe Institute, St.Petersburg, Russia along several directions of application of modern laser techniques for investigation of the dynamics of molecules relevant for biology and medicine. The particular directions under discussion will be as follows.
• Investigation of energy transfer in the excited states of molecular probes in solutions by means of polarized fluorescence spectroscopy.
• Pump-and-probe polarization modulation spectroscopy for investigation of sub-picosecond dynamics in excited biomolecules.
• Dynamics of singlet oxygen generation and degradation in solutions and on organic surfaces.

: Numerous studies have identified travelling waves in the cortex and suggested they play important roles in brain processing. These waves are most often measured using macroscopic methods that do not allow assessing wave dynamics at the single neuron scale and analyzed using techniques that smear neuronal excitability boundaries. In my talk, I will present a new approach for discriminating travelling waves from modular activation. Using this approach I will show that Calcium dynamics in mouse cortex and spiking activity in turtle cortex are dominated by modular activation rather than by propagating waves. I will then show how sequentially activating two discrete brain areas can appear as travelling waves in EEG simulations and present an analytical model in which modular activation generates wave-like activity with variable directions, velocities, and spatial patterns. I will end by illustrating why a careful distinction between modular and wave excitability profiles across scales will be critical for understanding the nature of cortical computations.

The microscopic theory of superconductivity was developed by John Bardeen, Leon N Cooper and J. Robert Schrieffer. It is among the most beautiful and outstanding achievements of modern scientific research. Almost half a century passed between the initial discovery of superconductivity by Kamerlingh Onnes and the theoretical explanation of the phenomenon. During the intervening years the brightest minds in theoretical physics tried and failed to develop a microscopic understanding of the effect. I will discuss some of those unsuccessful attempts to understand superconductivity. This not only demonstrates the extraordinary achievement made by formulating the BCS theory, but also illustrates that mistakes are a natural and healthy part of scientific discourse, and that inapplicable, even incorrect theories can turn out to be interesting and inspiring.

atom-probe tomograph (APT) can dissect a nanotip shaped specimen (radius