לוח שנה משולב

Submesoscale processes may strongly influence the depth and stratification of the ocean surface boundary layer, yet the prevalence of these motions throughout the ocean as well as the conditions that trigger them have been difficult to ascertain. Previous observational programs have focused on regions of strong frontal currents, such as the Gulf Stream and Kuroshio, where conditions are favorable for submesoscale instabilities. Here we present results from a unique times series of hydrographic observations, obtained at submesoscale resolution, from a region with a weak mean flow. As part of the Ocean Surface Mixing, Ocean Submesoscale Interaction Study (OSMOSIS) program, glider pairs occupied a small 20 km by 20 km region over the Porcupine Abyssal Plain in the northeast Atlantic from September 2012 to September 2013. Measurements from the gliders were complemented by a suite of nine mooring arrays in the same region. We analyze the in situ evolution in the context of the background conditions from satellite data, including sea surface temperature, sea surface height and surface forcing from wind stress reanalysis. We also analyze three months of a 1/48-degree ocean model in the same region. This data set provides an opportunity to study the physical processes that contribute to upper ocean mixed-layer variability over a full seasonal cycle.

We will present some analytic-algebraic approaches to the eigenvalues of the generator of the quantum Heisenberg ferromagnet; and discuss their relation to the conjecture that it undergoes a phase transition in the temperature in 3d. Based on joint works with Gil Alon, Omer Angel, James Propp and Gidi Amir.

Sensory stimuli in natural environments arise from many sources and the segregation of these sources into perceptually distinct objects is critical for an animal’s adaptive behavior. While segregation of visual and auditory signals has been studied extensively, little is known about the segregation of odors.
I will describe our study aiming to provide a description of the behavioral ability of macrosmatic mammals to segregate odors. Specifically, we asked how the ability to segregate odors relates to features of the individual odors that are mixed. We developed a behavioral task for mice in which they were trained to report the presence of specific target odorants embedded in random background mixtures. We found that mice are highly capable of segregating an odor-figure from a background. Relating behavioral accuracy to the representations of target and background odors by olfactory receptor neurons, we found that the difficulty of segregation is not related to the similarity between odors, but rather is explained by the amount of overlap in the representations of background and target odors.