לוח שנה משולב

The orbitofrontal cortex is strongly implicated in good (or at least normal) “decision-making”. Key to good decision-making is knowing the general value or "utility" of available options. Over the past decade, highly influential work has reported that the neurons in the orbitofrontal cortex signal this quantity. Yet the orbitofrontal cortex is typically not necessary for apparent value-based behaviors unless those behaviors require value predictions to be derived from access to complex models of the task, and the neural correlates cited above only part of a much richer representation linking the characteristics of specific outcomes (sensory, timing, unique value) that are expected and the events associated with obtaining them. In this workshop, I will review these data to argue that this aspect of encoding in the orbitofrontal cortex is actually what is critical in explaining the role of this area in both behavior and learning, and that any contribution of this area to economic decision-making stems from its unique role in allowing value to be derived (both within and without) from these environmental models.

Abstract
Solid-liquid interfaces (SLIs) occupy a central role in many phenomena ranging from surface electrochemistry to heterogeneous catalysis, wetting, heat transfer, proteins folding and function, ionic effects and self-assembly processes. All these processes crucially depend on the particular structural arrangement of the liquid molecules close to the solid. This so-called interfacial liquid tends to be more ordered and dense than bulk liquid due to its interaction with the solid’s surface. Its importance is further emphasized for soft materials such as polymers or biomolecules where the interfacial liquid is fully part of the structure [1].
Experimentally, SLIs are typically investigated through diffraction techniques that can provide atomic-level information about the liquid ordering but require averaging over large areas [2]. This renders diffraction experiments particularly challenging for irregular SLIs, for example if the solid exhibits nanoscale domains with different affinities for the surrounding solid.
Recently, I have developed an approach based on amplitude-modulation atomic force microscopy (AM-AFM) able to probe complex interfaces locally [3]. In this talk, I will show how, when operated in a particular regime, AM-AFM can be used to gain semi-quantitative information about the local free solvation energy of the solid with sub-nanometer resolution in all three dimensions. I will present several applications of the technique on mineral, biological as well as synthetic samples, discussing in each case how molecular-level structural effects within the SLI can lead to unexpected macroscopic changes in the interface properties. In particular, I will show how molecular-level chemical information about a surface can be derived from the interfacial liquid’s local properties. Finally, I will present results on synthetic nanoparticles where the surface functionalization is used to tune their wetting properties solely through structural effects [4], and draw a parallel with biomolecules of similar size.

Among the most interesting fireworks observed on the sky are the brightest - gamma ray bursts, GRBs, the least known - neutron star mergers, and the recently observed puzzling tidal disruption events. I present new results on GRBs progenitors, demonstrating on one hand the existence of a new group of objects: low-luminosity GRBs and providing on the other hand the first direct observational evidence for the Collapsar mechanism. I examine the links between these conclusions and short GRBs that are expected to arise from neutron star mergers and I predict the existence of long lasting flares from merger events. These could help identify gravitational radiation emission from mergers events, increasing the effective sensitivity of gravitational radiation detectors by a large factors. I examine the puzzling Swift events: J1644 and J2058 and explain why they were observed in non-thermal X-ray and not in the expected thermal UV. I also demonstrate surprising (theoretical) links between these three unrelated objects.