Emergence of Synchronous Oscillations in Neural Networks Excited by Noise

The presence of noise in non linear dynamical systems can play a constructive role, increasing the degree of order and coherence or evoking improvements in the performance of the system. An example of this positive influence in a biological system is the impulse transmission in neurons and the synchronization of a neural network. Integrating numerically the Fokker-Planck equation we show a self-induced synchronized oscillation. Such an oscillatory state appears in a neural network coupled with a feedback term, when this system is excited by noise and the noise strength is within a certain range.Comment: 12 pages, 18 figure

Dynamic Renormalization Group and Noise Induced Transitions in a Reaction Diffusion Model

We investigate how additive weak noise (correlated as well as uncorrelated) modifies the parameters of the Gray-Scott (GS) reaction diffusion system by performing numerical simulations and applying a Renormalization Group (RG) analysis in the neighborhood of the spatial scale where biochemical reactions take place. One can obtain the same sequence of spatial-temporal patterns by means of two equivalent routes: (i) by increasing only the noise intensity and keeping all other model parameters fixed, or (ii) keeping the noise fixed, and adjusting certain model parameters to their running scale-dependent values as predicted by the RG. This explicit demonstration validates the dynamic RG transformation for finite scales in a two-dimensional stochastic model and provides further physical insight into the coarse-graining analysis proposed by this scheme. Through several study cases we explore the role of noise and its temporal correlation in self-organization and propose a way to drive the system into a new desired state in a controlled way.Comment: 8 pages, 21 figure

A Xenon Mass Gauging through Heat Transfer Modeling for Electric Propulsion Thrusters

The authors gratefully acknowledge the financial support given for this work by the Swedish National Space Board (NRFP-3 Call), COMSOL® advisors and OHB-Sweden for their interest on this topic.Peer reviewedPublisher PD

Stochastic dynamics and Fokker-Planck equation in accelerator physics

The aim of this contribution is to study the particle dynamics in a storage ring under the influence of noise. Some simplified stochastic beam dynamics problems are treated by solving the corresponding Fokker-Planck equations numerically. (orig.)Available from TIB Hannover: RA 2999(98-173) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Measurements of coherent tune shift and head-tail growth rates at the SPS.

Introduction Several measurements and calculations similar to those described in this note have been performed in the past. Results are summarised in section 8. Most of them are quite old and moreover, there has been a significant spread in the vertical and horizontal broadband impedance parameters obtained (covering about a factor of 3, from 12 to 48 M# /m in Z v /Q). We are aiming for an uncertainty below 20%. This would allow us to follow up and document experimentally the various steps of improvements planned to reduce the impedance of the SPS as injector into the LHC. As much as possible, we try to perform the measurements with the same bunch dimensions. This minimises the model dependence and uncertainties due to variation in bunch parameters. 2 Beam conditions The measurements were all performed using single and relatively short bunches (# z # 16 cm or 0.55 ns) injec

Deficient Endoplasmic Reticulum-Mitochondrial Phosphatidylserine Transfer Causes Liver Disease

Non-alcoholic fatty liver is the most common liver disease worldwide. Here, we show that the mitochondrial protein mitofusin 2 (Mfn2) protects against liver disease. Reduced Mfn2 expression was detected in liver biopsies from patients with non-alcoholic steatohepatitis (NASH). Moreover, reduced Mfn2 levels were detected in mouse models of steatosis or NASH, and its re-expression in a NASH mouse model ameliorated the disease. Liver-specific ablation of Mfn2 in mice provoked inflammation, triglyceride accumulation, fibrosis, and liver cancer. We demonstrate that Mfn2 binds phosphatidylserine (PS) and can specifically extract PS into membrane domains, favoring PS transfer to mitochondria and mitochondrial phosphatidylethanolamine (PE) synthesis. Consequently, hepatic Mfn2 deficiency reduces PS transfer and phospholipid synthesis, leading to endoplasmic reticulum (ER) stress and the development of a NASH-like phenotype and liver cancer. Ablation of Mfn2 in liver reveals that disruption of ER-mitochondrial PS transfer is a new mechanism involved in the development of liver disease.This study was supported by the MINECO (SAF2016-75246R), the Generalitat de Catalunya (2014SGR48, 2017SGR696, ICREA Acadèmia), INFLAMES (PIE-14/00045, ISCIII), CIBERDEM, ISCIII, INTERREG IV-B-SUDOE-FEDER (DIOMED, SOE1/P1/E178), and “la Caixa” Foundation. S.F.-V. acknowledges support from the Miguel Servet tenure-track program (CP10/00438 and CPII16/00008) from the Fondo de Investigación Sanitaria, co-financed by the ERD. We gratefully acknowledge institutional funding from the MINECO through the Centres of Excellence Severo Ochoa Award and from the CERCA Programme of the Generalitat de Catalunya

The roles played by the British Chiefs of Staff Committee in the evolution of Britain's nuclear weapon planning and policy-making, 1945-55

SIGLEAvailable from British Library Document Supply Centre- DSC:DX84631 / BLDSC - British Library Document Supply CentreGBUnited Kingdo