לוח שנה משולב

During the last decade electron microscopy become a powerful tool in structural studies of large biological complexes. Cryo electron microscopy enabled us to reveal molecular dynamics of the complexes by analysis of samples in solution. This was made possible by long-standing efforts in sample preparations (cryo-EM imaging), in development of hardware, automation in data collection, methods in image analysis and, eventually, interpretation of results. Here I would like to share my experience in using these approaches in analysis of structural organisation of bacteriophages exemplified by the SPP1 phage. It is important to highlight critical steps in obtaining near-atomic resolution structures of the biocomplexes. We have obtained high resolution structures of main components of the phage such as a capsid and its nano-motor engaged into packaging of genome and its release.

All living organisms extract chemical information from the surrounding world. We know a lot about the genetic, cellular, and anatomical organization of our sense of smell, which has similar organization from insects to mammals. However, we still do not know basic principles of odor coding, organization of the odor parameter space, and how odors are represented in the brain. In humans, odors are sensed by millions of receptor cells using ~350 types of receptor cells. Flies have 60 and mice ~1000 receptor types. An odor evokes a concentration-dependent spatial-temporal pattern of receptor cell activity. We are presented with an immensely complex combinatorial computation. And the central question of my research is to understand how these patterns are read by the brain.
In this talk I will present our recent results on testing a novel model for concentration-invariant odor coding based on temporal ranking of receptor. And then I will discuss our attempt to build a theory of odor space representation in the brain based on this model.

The large-scale midlatitude flow is dominated by Rossby wave activity along the upper-level midlatitude wave guide and jet stream. This activity often occurs in preferred quasi-stationary, persistent, and recurrent states, so-called weather regimes (e.g. Vautard, 1990). Many of these regimes are dominated by a blocking anticyclone. In the Atlantic-European region, weather regimes explain most of the atmospheric variability on sub-seasonal time scales. From a forecasting perspective, the onset, persistence, and transition of weather regimes present a severe challenge in current numerical weather prediction models (Ferranti et al., 2015).
In this presentation Atlantic-European weather regimes are revisited in order to elucidate their linkage to the eddy-driven jet, atmospheric blocking, and the physical and dynamical processes governing their life cycles. For the latter, the focus is on air mass transport into the upper troposphere through "diabatic outflow" driven by latent heat release in ascending air streams associated with synoptic-scale weather systems (e.g. Grams and Archambault 2016). Next to dry dynamics, this process has recently been shown to be of first-order in blocking onset and maintenance (Pfahl et al. 2015). Challenges in predictability of weather regime life cycles imposed by diabatic outflow are exemplarily demonstrated for a recent forecast bust. We further briefly discuss the modulation of weather regime life cycles by climate modes on sub-seasonal time scales such as the stratosphere and Madden-Julian Oscillation.
Finally, the role of weather regimes in extreme weather and the relevance of the weather regime paradigm for socio-economic activities are demonstrated.