3,120 research outputs found

    Electroencephalographic field influence on calcium momentum waves

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    Macroscopic EEG fields can be an explicit top-down neocortical mechanism that directly drives bottom-up processes that describe memory, attention, and other neuronal processes. The top-down mechanism considered are macrocolumnar EEG firings in neocortex, as described by a statistical mechanics of neocortical interactions (SMNI), developed as a magnetic vector potential A\mathbf{A}. The bottom-up process considered are Ca2+\mathrm{Ca}^{2+} waves prominent in synaptic and extracellular processes that are considered to greatly influence neuronal firings. Here, the complimentary effects are considered, i.e., the influence of A\mathbf{A} on Ca2+\mathrm{Ca}^{2+} momentum, p\mathbf{p}. The canonical momentum of a charged particle in an electromagnetic field, Π=p+qA\mathbf{\Pi} = \mathbf{p} + q \mathbf{A} (SI units), is calculated, where the charge of Ca2+\mathrm{Ca}^{2+} is q=−2eq = - 2 e, ee is the magnitude of the charge of an electron. Calculations demonstrate that macroscopic EEG A\mathbf{A} can be quite influential on the momentum p\mathbf{p} of Ca2+\mathrm{Ca}^{2+} ions, in both classical and quantum mechanics. Molecular scales of Ca2+\mathrm{Ca}^{2+} wave dynamics are coupled with A\mathbf{A} fields developed at macroscopic regional scales measured by coherent neuronal firing activity measured by scalp EEG. The project has three main aspects: fitting A\mathbf{A} models to EEG data as reported here, building tripartite models to develop A\mathbf{A} models, and studying long coherence times of Ca2+\mathrm{Ca}^{2+} waves in the presence of A\mathbf{A} due to coherent neuronal firings measured by scalp EEG. The SMNI model supports a mechanism wherein the p+qA\mathbf{p} + q \mathbf{A} interaction at tripartite synapses, via a dynamic centering mechanism (DCM) to control background synaptic activity, acts to maintain short-term memory (STM) during states of selective attention.Comment: Final draft. http://ingber.com/smni14_eeg_ca.pdf may be updated more frequentl

    The Incremental Cooperative Design of Preventive Healthcare Networks

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    This document is the Accepted Manuscript version of the following article: Soheil Davari, 'The incremental cooperative design of preventive healthcare networks', Annals of Operations Research, first published online 27 June 2017. Under embargo. Embargo end date: 27 June 2018. The final publication is available at Springer via http://dx.doi.org/10.1007/s10479-017-2569-1.In the Preventive Healthcare Network Design Problem (PHNDP), one seeks to locate facilities in a way that the uptake of services is maximised given certain constraints such as congestion considerations. We introduce the incremental and cooperative version of the problem, IC-PHNDP for short, in which facilities are added incrementally to the network (one at a time), contributing to the service levels. We first develop a general non-linear model of this problem and then present a method to make it linear. As the problem is of a combinatorial nature, an efficient Variable Neighbourhood Search (VNS) algorithm is proposed to solve it. In order to gain insight into the problem, the computational studies were performed with randomly generated instances of different settings. Results clearly show that VNS performs well in solving IC-PHNDP with errors not more than 1.54%.Peer reviewe
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