לוח שנה משולב

When a polymer is quickly compressed it reaches a crumpled state that has attracted much attention as a model for DNA organization in the nucleus, conjectured to have a fractal struc-ture that has so far remained elusive. We will describe the relations between topology of knots, slow relaxation and the fast crumpling of the polymer, and propose a model for the col-lapse as a process similar to water drops condensing on a surface. Our model reproduces fea-tures of this state quantitatively, suggesting that the slow approach to scaling is related to a large dispersion in the sizes of ‘water drops’. Time permitting, we will present a model of unentangled directed polymers, whose universal properties are found to differ significantly from predictions of the best available theories. This suggests new directions in treating non-local topological constraints in polymer systems, a major open theoretical challenge.

The talk will present new expected and unexpected results from the Dark Energy Survey beyond cosmological studies:
e.g. solar system objects, Milky Way companions, galaxy clusters, and high-redshift objects.

: Neuronal plasticity is a unique property that describes the ability of the system to undergo long-lasting changes, typically as a result of experience. This paradigm, initially discovery by Bliss and Lomo and dubbed long term potentiation (LTP), describes a scenario where the post-synaptic responses increase in strength for long durations, following a particular pre-synaptic stimulus. Conversely, LT-Depression, describes the long lasting depression of synaptic responses. Today, these phenomena are commonly used to describe the molecular model for learning and memory. A large body of work has implicated more than a hundred proteins and factors in modulating LTP and LTD, and thereby memory. Unfortunately, there is still a lively debate regarding the true necessity and exact role of each player. The need for new techniques and approaches to further explore synaptic function and dysfunction has never been more pressing, as the number of people developing neurodegenerative diseases rises exponentially to epidemic scales, with the aging population. These diseases are characterized by a strong decline in the number of synapses and in the ability of synapses to undergo plasticity, ultimately resulting in the severe decline of cognitive function- such as learning and memory. To better scrutinize synaptic plasticity and probe the function and role of its initiators (i.e. NMDA receptors and calcium ions), I have developed novel light-gated NMDA receptors and photoactivatable fluorescent Ca2+-probes to monitor synaptic activity with unmet spatio-temporal resolution and reversibility. I use the latter to examine the roles of specific NMDA-receptor subunits in plasticity.