Past OCCAM Special Seminar

8 July 2010
10:00
Professor Georgiy L. Stenchikov
Abstract
Strong explosive volcanic eruptions could inject in the lower stratosphere million tons of SO2, which being converted to sulfate aerosols, affect radiative balance of the planet for a few years. During this period the volcanic radiative forcing dominates other forcings producing distinct detectable climate responses. Therefore volcanic impacts provide invaluable natural test of climate nonlinearities and feedback mechanisms. In this talk I will overview volcanic impacts on tropospheric and strsatospheric temperature, ozone, high-latitude circulation, stratosphere-troposphere dynamic interaction, and focus on the long-term volcanic effect on ocean heat content and sea level.
  • OCCAM Special Seminar
24 November 2009
16:30
Abstract
1. "Approximate approximations" and accurate computation of high dimensional potentials. 2. Iteration procedures for ill-posed boundary value problems with preservation of the differential equation. 3. Asymptotic treatment of singularities of solutions generated by edges and vertices at the boundary. 4. Compound asymptotic expansions for solutions to boundary value problems for domains with singularly perturbed boundaries. 5. Boundary value problems in perforated domains without homogenization.
  • OCCAM Special Seminar
21 September 2009
16:30
Abstract
We have recently found a way to describe large-scale neural activity in terms of non-equilibrium statistical mechanics. This allows us to calculate perturbatively the effects of fluctuations and correlations on neural activity. Major results of this formulation include a role for critical branching, and the demonstration that there exist non-equilibrium phase transitions in neocortical activity which are in the same universality class as directed percolation. This result leads to explanations for the origin of many of the scaling laws found in LFP, EEG, fMRI, and in ISI distributions, and provides a possible explanation for the origin of various brain waves. It also leads to ways of calculating how correlations can affect neocortical activity, and therefore provides a new tool for investigating the connections between neural dynamics, cognition and behavior
  • OCCAM Special Seminar

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