Search results for "coupling [Lambda(1520)]"
showing 10 items of 501 documents
Coupling agent-based with equation-based models to study spatially explicit megapopulation dynamics
2018
International audience; The incorporation of the spatial heterogeneity of real landscapes into population dynamics remains extremely difficult. We propose combining equation-based modelling (EBM) and agent-based modelling (ABM) to overcome the difficulties classically encountered. ABM facilitates the description of entities that act according to specific rules evolving on various scales. However, a large number of entities may lead to computational difficulties (e.g., for populations of small mammals, such as voles, that can exceed millions of individuals). Here, EBM handles age-structured population growth, and ABM represents the spreading of voles on large scales. Simulations applied to t…
Vibronic Model for Intercommunication of Localized Spins via Itinerant Electron
2019
In this article, we propose a vibronic pseudo Jahn–Teller model for partially delocalized mixed-valence molecules aimed to describe the magnetic coupling between the localized spins mediated by the delocalized electron. The simplest partially delocalized system that retains the main studied features is assumed to consist of a one-electron mixed-valence dimer, which is connected to the two terminal magnetic ions. The model involves the following key interactions: electron transfer in the spin-delocalized subsystem of a mixed-valence molecule, which is mimicked by a dimeric unit, coupling of the itinerant electrons with the molecular vibrations, and isotropic magnetic exchange between the loc…
Vibration reduction on city buses: Determination of optimal position of engine mounts
2010
International audience; This study is composed of three essential parts. The first part describes an indirect semi-experimental method which is used to reconstruct the excitation force of an operating diesel engine from the acceleration data measured at the mounting points. These internal forces can not be directly measured with force sensors; they have to be derived from the dynamic deformation of the engine support, so a theoretical analysis is carried out to derive the equations for the force re-construction.The second part deals with prevention of low frequency vibration of the powertrain from spreading to the rest of the vehicle. Three uncoupling techniques are used to minimize these v…
Crowd-Averse Robust Mean-Field Games: Approximation via State Space Extension
2016
We consider a population of dynamic agents, also referred to as players. The state of each player evolves according to a linear stochastic differential equation driven by a Brownian motion and under the influence of a control and an adversarial disturbance. Every player minimizes a cost functional which involves quadratic terms on state and control plus a cross-coupling mean-field term measuring the congestion resulting from the collective behavior, which motivates the term “crowd-averse.” Motivations for this model are analyzed and discussed in three main contexts: a stock market application, a production engineering example, and a dynamic demand management problem in power systems. For th…
Design of a telescopic tower for wind energy production with reduced environmental impact
2019
A prototype of a telescopic pole for wind energy production with low environmental impact and its lifting system for a 60 to 250 kW turbine and a height of 30 m have been designed and manufactured. A telescopic tower, which is raised and lowered by automation or by remote control, allows to differentiate the presence of the generator within the landscape over time. The technology currently available for lifting and lowering wind turbines is made up of telescopic poles of heights of less than 10 meters and with tilting posts of height below 30 m. Without a state of the art to refer to, the telescopic pole and its lifting system have been designed starting from scratch and solving with innova…
Temporal-spatial characteristics of phase-amplitude coupling in electrocorticogram for human temporal lobe epilepsy.
2017
Objective Neural activity of the epileptic human brain contains low- and high-frequency oscillations in different frequency bands, some of which have been used as reliable biomarkers of the epileptogenic brain areas. However, the relationship between the low- and high-frequency oscillations in different cortical areas during the period from pre-seizure to post-seizure has not been completely clarified. Methods We recorded electrocorticogram data from the temporal lobe and hippocampus of seven patients with temporal lobe epilepsy. The modulation index based on the Kullback-Leibler distance and the phase-amplitude coupling co-modulogram were adopted to quantify the coupling strength between t…
NO Hemodynamic Speed Limit for Hippocampal Neurogenesis
2019
Newborn dentate granule cells (DGCs) are continuously generated in the adult brain. The mechanism underlying how the adult brain governs hippocampal neurogenesis remains poorly understood. In this study, we investigated how coupling of pre-existing neurons to the cerebrovascular system regulates hippocampal neurogenesis. Using a new in vivo imaging method in freely moving mice, we found that hippocampus-engaged behaviors, such as exploration in a novel environment, rapidly increased microvascular blood flow velocity in the dentate gyrus. Importantly, blocking this exploration-elevated blood flow dampened experience-induced hippocampal neurogenesis. By imaging the neurovascular niche in comb…
Bioelectrical Coupling of Single-Cell States in Multicellular Systems.
2020
The spatiotemporal distributions of signaling ions and molecules that modulate biochemical pathways in nonexcitable cells are influenced by multicellular electric potentials. These potentials act as distributed controllers encoding instructive spatial patterns in development and regeneration. We review experimental facts and discuss recent bioelectrical models that provide new physical insights and complement biochemical approaches. Single-cell states are modulated at the multicellular level because of the coupling between neighboring cells, thus allowing memories and multicellular patterns. The model is based on (i) two generic voltage-gated ion channels that promote the polarized and depo…
Intercellular Connectivity and Multicellular Bioelectric Oscillations in Nonexcitable Cells: A Biophysical Model
2018
Bioelectricity is emerging as a crucial mechanism for signal transmission and processing from the single-cell level to multicellular domains. We explore theoretically the oscillatory dynamics that result from the coupling between the genetic and bioelectric descriptions of nonexcitable cells in multicellular ensembles, connecting the genetic prepatterns defined over the ensemble with the resulting spatio-temporal map of cell potentials. These prepatterns assume the existence of a small patch in the ensemble with locally low values of the genetic rate constants that produce a specific ion channel protein whose conductance promotes the cell-polarized state (inward-rectifying channel). In this…
Comment on “Innovative scattering analysis shows that hydrophobic disordered proteins are expanded in water”
2018
Editors at Science requested our input on the above discussion (comment by Best et al . and response by Riback et al .) because both sets of authors use our data from Fuertes et al . (2017) to support their arguments. The topic of discussion pertains to the discrepant inferences drawn from SAXS versus FRET measurements regarding the dimensions of intrinsically disordered proteins (IDPs) in aqueous solvents. Using SAXS measurements on labeled and unlabeled proteins, we ruled out the labels used for FRET measurements as the cause of discrepant inferences between the two methods. Instead, we propose that FRET and SAXS provide complementary readouts because of a decoupling of size and shape fl…