keyword
MENU ▼
Read by QxMD icon Read
search

Phase amplitude coupling

keyword
https://www.readbyqxmd.com/read/28522816/dynamical-dispersion-engineering-in-coupled-vertical-cavities-employing-a-high-contrast-grating
#1
Alireza Taghizadeh, Il-Sug Chung
Photon's effective mass is an important parameter of an optical cavity mode, which determines the strength of light-matter interaction. Here, we propose a novel method for controlling the photon's effective mass by using coupled photonic cavities and designing the angular dependence of the coupling strength. This can be implemented by employing a high-contrast grating (HCG) as the coupling reflector in a system of two coupled vertical cavities, and engineering both the HCG reflection phase and amplitude response...
May 18, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28520976/pattern-formation-in-multiphase-models-of-chemotactic-cell-aggregation
#2
J E F Green, J P Whiteley, J M Oliver, H M Byrne, S L Waters
We develop a continuum model for the aggregation of cells cultured in a nutrient-rich medium in a culture well. We consider a 2D geometry, representing a vertical slice through the culture well, and assume that the cell layer depth is small compared with the typical lengthscale of the culture well. We adopt a continuum mechanics approach, treating the cells and culture medium as a two-phase mixture. Specifically, the cells and culture medium are treated as fluids. Additionally, the cell phase can generate forces in response to environmental cues, which include the concentration of a chemoattractant that is produced by the cells within the culture medium...
May 16, 2017: Mathematical Medicine and Biology: a Journal of the IMA
https://www.readbyqxmd.com/read/28515446/phase-channel-dynamics-reveal-the-role-of-impurities-and-screening-in-a-quasi-one-dimensional-charge-density-wave-system
#3
M D Thomson, K Rabia, F Meng, M Bykov, S van Smaalen, H G Roskos
Charge density waves (CDWs), i.e. the periodic spatial modulation of coupled electronic and lattice density, are ubiquitous in low-dimensional conductors and have taken on renewed relevance due their role in state-of-the-art materials, e.g. high-T c superconductors, topological insulators and low-dimensional carbon. As CDWs are described by a complex order parameter to represent both the amplitude and phase, they are formally analogous to BCS superconductors and spin-waves, providing a prototype of collective phenomena for the further development of field theories and ab-initio calculations of complex solids...
May 17, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28505829/control-of-amplitude-chimeras-by-time-delay-in-oscillator-networks
#4
Aleksandar Gjurchinovski, Eckehard Schöll, Anna Zakharova
We investigate the influence of time-delayed coupling in a ring network of nonlocally coupled Stuart-Landau oscillators upon chimera states, i.e., space-time patterns with coexisting partially coherent and partially incoherent domains. We focus on amplitude chimeras, which exhibit incoherent behavior with respect to the amplitude rather than the phase and are transient patterns, and we show that their lifetime can be significantly enhanced by coupling delay. To characterize their transition to phase-lag synchronization (coherent traveling waves) and other coherent structures, we generalize the Kuramoto order parameter...
April 2017: Physical Review. E
https://www.readbyqxmd.com/read/28482160/photoinduced-intra-and-intermolecular-energy-transfer-in-chlorophyll-a-dimer
#5
Fulu Zheng, Sebastian Fernandez-Alberti, Sergei Tretiak, Yang Zhao
Applying non-adiabatic excited-state molecular dynamics (NA-ESMD), we investigate excitation energy transfer and exciton localization dynamics in a chlorophyll (Chl) a dimer system at the interface of two monomers of light-harvesting complex II (LHCII) trimer. After its optical excitation in the red edge of the Soret (B) band, the Chla dimer experiences an ultrafast intra- and intermolecular nonradiative relaxation process to the lowest band (Qy). The energy relaxation is found to run faster in the the Chla dimer than in the Chla monomer...
May 8, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28480817/plasticity-in-the-period-of-the-circadian-pacemaker-induced-by-phase-dispersion-of-its-constituent-cellular-clocks
#6
Domien G M Beersma, Kim A Gargar, Serge Daan
The mammalian circadian pacemaker is commonly thought to be a rigid oscillator that generates output under a variety of circumstances that differ only in phase, period, and/or amplitude. Yet the pacemaker is composed of many cells that each can respond to varying circumstances in different ways. Computer simulations demonstrate that networks of such pacemaker cells behave differently under a light-dark cycle compared with constant darkness. The differences demonstrate that the circadian pacemaker is plastic: The pacemaker shapes its properties in response to the circumstances...
May 1, 2017: Journal of Biological Rhythms
https://www.readbyqxmd.com/read/28476919/v%C3%AC-o2-kinetics-associated-with-moderate-intensity-exercise-in-heart-failure-impact-of-intrathecal-fentanyl-inhibition-of-group-iii-iv-locomotor-muscle-afferents
#7
Erik H Van Iterson, Bruce D Johnson, Michael J Joyner, Timothy B Curry, Thomas P Olson
Heart failure (HF) patients demonstrate impaired pulmonary, circulatory, and nervous system responses to exercise. While HF demonstrate prolonged (time-constant, τ) pulmonary oxygen uptake (V̇O2) on-kinetics contributing to exercise intolerance, it is unknown if abnormal V̇O2 kinetics couple with ventilatory and circulatory dysfunction secondary to impaired group III/IV afferents in HF. Because lower-lumbar intrathecal fentanyl inhibits locomotor muscle afferents resulting in improved exercise ventilation and hemodynamics, we tested the hypotheses, HF will demonstrate: 1) rapid V̇O2 on-kinetics, and 2) attenuated steady-state V̇O2 amplitude and oxygen deficit (O2def) during exercise with fentanyl versus placebo...
May 5, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28468351/local-modulation-of-double-optomechanically-induced-transparency-and-amplification
#8
Q Yang, B P Hou, D G Lai
We consider the probe absorption properties in a mechanically coupled optomechanical system in which the two coupled nanomechanical oscillators are driven by the time-dependent forces, respectively. It is found that the mechanical interaction splits the transparency window for a usual single-mode optomechanical system into two parts and then leads to appearance of the double optomechanically induced transparency. The distance between the two transparency positions (the frequency for the maximal transparency) is determined by the mechanical interaction amplitude...
May 1, 2017: Optics Express
https://www.readbyqxmd.com/read/28467703/simulation-of-vibronic-spectra-of-flexible-systems-hybrid-dvr-harmonic-approaches
#9
Alberto Baiardi, Julien Bloino, Vincenzo Barone
Our general framework for the simulation of vibrational signatures in electronic spectra has been extended to treat one large-amplitude motion (LAM) at the anharmonic level, coupled to the other small amplitude motions (SAM) treated as harmonic. The coupling between LAM and SAM is minimized thanks to the use of delocalized internal coordinates, which are built automatically from the molecular topology. General LAMs can be employed, ranging from intrinsic reaction coordinates to rigid or flexible paths based on the distinguished coordinate approach...
May 3, 2017: Journal of Chemical Theory and Computation
https://www.readbyqxmd.com/read/28456176/on-off-intermittency-in-coupled-chaotic-thermoacoustic-oscillations
#10
Rémi Delage, Yusuke Takayama, Tetsushi Biwa
This paper documents on-off intermittency observed in coupled thermoacoustic chaotic oscillations. Mode competition between two or three oscillation modes engenders chaotic oscillations through quasiperiodic oscillations introduced by a local cross-sectional change in a gas-filled tube. Complete synchronization is then obtained by connecting two thermoacoustic chaotic oscillators via a rigid plate with an orifice. From the analysis of pressure fluctuations, theoretical statistical scaling laws related to the laminar phases, spectral density, and amplitude probability distribution are found to be satisfied in the coupled thermoacoustic oscillators, when the thermoacoustic complete synchronization breaks down through an on-off intermittency route with the decreased orifice size...
April 2017: Chaos
https://www.readbyqxmd.com/read/28446582/auditory-fear-conditioning-modifies-steady-state-evoked-potentials-in-the-rat-inferior-colliculus
#11
André Luiz Vieira Lockmann, Flavio Afonso Gonçalves Mourão, Márcio Flávio Dutra Moraes
The rat inferior colliculus (IC) is a major midbrain relay for ascending inputs from the auditory brainstem and has been suggested to play a key role in the processing of aversive sounds. Previous studies have demonstrated that auditory fear conditioning (AFC) potentiates transient responses to brief tones in the IC, but it remains unexplored whether AFC modifies responses to sustained periodic acoustic stimulation - a type of response called steady-state evoked potential (SSEP). Here we used an amplitude-modulated tone - 10 kHz tone with a sinusoidal amplitude modulation of 53...
April 26, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28441393/sequence-learning-modulates-neural-responses-and-oscillatory-coupling-in-human-and-monkey-auditory-cortex
#12
Yukiko Kikuchi, Adam Attaheri, Benjamin Wilson, Ariane E Rhone, Kirill V Nourski, Phillip E Gander, Christopher K Kovach, Hiroto Kawasaki, Timothy D Griffiths, Matthew A Howard, Christopher I Petkov
Learning complex ordering relationships between sensory events in a sequence is fundamental for animal perception and human communication. While it is known that rhythmic sensory events can entrain brain oscillations at different frequencies, how learning and prior experience with sequencing relationships affect neocortical oscillations and neuronal responses is poorly understood. We used an implicit sequence learning paradigm (an "artificial grammar") in which humans and monkeys were exposed to sequences of nonsense words with regularities in the ordering relationships between the words...
April 2017: PLoS Biology
https://www.readbyqxmd.com/read/28430436/time-domain-thz-spectroscopy-reveals-coupled-protein-hydration-dielectric-response-in-solutions-of-native-and-fibrils-of-human-lysozyme
#13
Fabio Novelli, Saeideh Ostovar Pour, Jonathan Tollerud, Ashkan Roozbeh, Dominique R T Appadoo, Ewan W Blanch, Jeffrey A Davis
Here we reveal details of the interaction between human lysozyme proteins, both native and fibrils, and their water environment by intense terahertz time domain spectroscopy. With the aid of a rigorous dielectric model, we determine the amplitude and phase of the oscillating dipole induced by the THz field in the volume containing the protein and its hydration water. At low concentrations, the amplitude of this induced dipolar response decreases with increasing concentration. Beyond a certain threshold, marking the onset of the interactions between the extended hydration shells, the amplitude remains fixed but the phase of the induced dipolar response, which is initially in phase with the applied THz field, begins to change...
May 11, 2017: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/28429783/fine-structure-of-the-topological-defect-cores-studied-for-disclinations-in-lyotropic-chromonic-liquid-crystals
#14
Shuang Zhou, Sergij V Shiyanovskii, Heung-Shik Park, Oleg D Lavrentovich
The detailed structure of singularities of ordered field represents a fundamental problem in diverse areas of physics. At the defect cores, the deformations are so strong that the system explores states with symmetry different from that of an undistorted material. These regions are difficult to explore experimentally as their spatial extension is very small, a few molecular lengths in the condensed matter. Here we explore the cores of disclinations in the so-called chromonic nematics that extend over macroscopic length scales accessible for optical characterization...
April 21, 2017: Nature Communications
https://www.readbyqxmd.com/read/28424606/bifurcation-analysis-on-phase-amplitude-cross-frequency-coupling-in-neural-networks-with-dynamic-synapses
#15
Takumi Sase, Yuichi Katori, Motomasa Komuro, Kazuyuki Aihara
We investigate a discrete-time network model composed of excitatory and inhibitory neurons and dynamic synapses with the aim at revealing dynamical properties behind oscillatory phenomena possibly related to brain functions. We use a stochastic neural network model to derive the corresponding macroscopic mean field dynamics, and subsequently analyze the dynamical properties of the network. In addition to slow and fast oscillations arising from excitatory and inhibitory networks, respectively, we show that the interaction between these two networks generates phase-amplitude cross-frequency coupling (CFC), in which multiple different frequency components coexist and the amplitude of the fast oscillation is modulated by the phase of the slow oscillation...
2017: Frontiers in Computational Neuroscience
https://www.readbyqxmd.com/read/28424599/electrophysiological-sequelae-of-hemispherotomy-in-ipsilateral-human-cortex
#16
Ammar H Hawasli, Ravi Chacko, Nicholas P Szrama, David T Bundy, Mrinal Pahwa, Chester K Yarbrough, Brian J Dlouhy, David D Limbrick, Dennis L Barbour, Matthew D Smyth, Eric C Leuthardt
Objectives: Hemispheric disconnection has been used as a treatment of medically refractory epilepsy and evolved from anatomic hemispherectomy to functional hemispherectomies to hemispherotomies. The hemispherotomy procedure involves disconnection of an entire hemisphere with limited tissue resection and is reserved for medically-refractory epilepsy due to diffuse hemispheric disease. Although it is thought to be effective by preventing seizures from spreading to the contralateral hemisphere, the electrophysiological effects of a hemispherotomy on the ipsilateral hemisphere remain poorly defined...
2017: Frontiers in Human Neuroscience
https://www.readbyqxmd.com/read/28424297/magnitude-and-behavior-of-cross-talk-effects-in-multi-channel-electrophysiology-experiments
#17
Matthew John Nelson, Silvana Valtcheva, Laurent Venance
Modern neurophysiological experiments frequently involve multiple channels separated by very small distances. A unique methodological concern for multiple electrode experiments is that of capacitive coupling (cross-talk) between channels. Yet the nature of the cross-talk recording circuit is not well known in the field and the extent to which it practically affects neurophysiology experiments has never been fully investigated. Here we describe a simple electrical circuit model of simultaneous recording and stimulation with two or more channels and experimentally verify the model using ex vivo brain slice and in vivo whole-brain preparations...
April 19, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28416595/nonsinusoidal-beta-oscillations-reflect-cortical-pathophysiology-in-parkinson-s-disease
#18
Scott R Cole, Roemer van der Meij, Erik J Peterson, Coralie de Hemptinne, Philip A Starr, Bradley Voytek
Oscillations in neural activity play a critical role in neural computation and communication. There is intriguing new evidence that the nonsinusoidal features of the oscillatory waveforms may inform underlying physiological and pathophysiological characteristics. Time-domain waveform analysis approaches stand in contrast to traditional Fourier-based methods, which alter or destroy subtle waveform features. Recently, it has been shown that the waveform features of oscillatory beta (13-30 Hz) events, a prominent motor cortical oscillation, may reflect near-synchronous excitatory synaptic inputs onto cortical pyramidal neurons...
May 3, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28401931/early-neurovascular-dysfunction-in-a-transgenic-rat-model-of-alzheimer-s-disease
#19
Illsung L Joo, Aaron Y Lai, Paolo Bazzigaluppi, Margaret M Koletar, Adrienne Dorr, Mary E Brown, Lynsie A M Thomason, John G Sled, JoAnne McLaurin, Bojana Stefanovic
Alzheimer's disease (AD), pathologically characterized by amyloid-β peptide (Aβ) accumulation, neurofibrillary tangle formation, and neurodegeneration, is thought to involve early-onset neurovascular abnormalities. Hitherto studies on AD-associated neurovascular injury have used animal models that exhibit only a subset of AD-like pathologies and demonstrated some Aβ-dependent vascular dysfunction and destabilization of neuronal network. The present work focuses on the early stage of disease progression and uses TgF344-AD rats that recapitulate a broader repertoire of AD-like pathologies to investigate the cerebrovascular and neuronal network functioning using in situ two-photon fluorescence microscopy and laminar array recordings of local field potentials, followed by pathological analyses of vascular wall morphology, tau hyperphosphorylation, and amyloid plaques...
April 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28400257/phase-amplitude-coupled-persistent-theta-and-gamma-oscillations-in-rat-primary-motor-cortex-in%C3%A2-vitro
#20
Nicholas W Johnson, Mazhar Özkan, Adrian P Burgess, Emma J Prokic, Keith A Wafford, Michael J O'Neill, Stuart D Greenhill, Ian M Stanford, Gavin L Woodhall
In vivo, theta (4-7 Hz) and gamma (30-80 Hz) neuronal network oscillations are known to coexist and display phase-amplitude coupling (PAC). However, in vitro, these oscillations have for many years been studied in isolation. Using an improved brain slice preparation technique we have, using co-application of carbachol (10 μM) and kainic acid (150 nM), elicited simultaneous theta (6.6 ± 0.1 Hz) and gamma (36.6 ± 0.4 Hz) oscillations in rodent primary motor cortex (M1). Each oscillation showed greatest power in layer V...
April 8, 2017: Neuropharmacology
keyword
keyword
86889
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"