31,583 research outputs found
Optimal cellular mobility for synchronization arising from the gradual recovery of intercellular interactions
Cell movement and intercellular signaling occur simultaneously during the
development of tissues, but little is known about how movement affects
signaling. Previous theoretical studies have shown that faster moving cells
favor synchronization across a population of locally coupled genetic
oscillators. An important assumption in these studies is that cells can
immediately interact with their new neighbors after arriving at a new location.
However, intercellular interactions in cellular systems may need some time to
become fully established. How movement affects synchronization in this
situation has not been examined. Here we develop a coupled phase oscillator
model in which we consider cell movement and the gradual recovery of
intercellular coupling experienced by a cell after movement, characterized by a
moving rate and a coupling recovery rate respectively. We find (1) an optimal
moving rate for synchronization, and (2) a critical moving rate above which
achieving synchronization is not possible. These results indicate that the
extent to which movement enhances synchrony is limited by a gradual recovery of
coupling. These findings suggest that the ratio of time scales of movement and
signaling recovery is critical for information transfer between moving cells.Comment: 18 single column pages + 1 table + 5 figures + Supporting Informatio
Gradual Synchronization
A synchronization solution is developed in order to allow finer grained segmentation of clock domains on a chip. This solution incorporates computation into the synchronization overhead time and is called Gradual Synchronization. With Gradual Synchronization as a synchronization method the design space of a chip could easily mix both asynchronous and synchronous blocks of logic, paving the way for wider use of asynchronous logic design
Lightweight Synchronization Algorithm with Self-Calibration for Industrial LORA Sensor Networks
Wireless sensor and actuator networks are gaining momentum in the era of
Industrial Internet of Things IIoT. The usage of the close-loop data from
sensors in the manufacturing chain is extending the common monitoring scenario
of the Wireless Sensors Networks WSN where data were just logged. In this paper
we present an accurate timing synchronization for TDMA implemented on the state
of art IoT radio, such as LoRa, that is a good solution in industrial
environments for its high robustness. Experimental results show how it is
possible to modulate the drift correction and keep the synchronization error
within the requirements
Synchronization in A Carpet of Hydrodynamically Coupled Rotors with Random Intrinsic Frequency
We investigate synchronization caused by long-range hydrodynamic interaction
in a two-dimensional, substrated array of rotors with random intrinsic
frequencies. The rotor mimics a flagellated bacterium that is attached to the
substrate ("bacterial carpet") and exerts an active force on the fluid.
Transition from coherent to incoherent regimes is studied numerically, and the
results are compared to a mean-field theory. We show that quite a narrow
distribution of the intrinsic frequency is required to achieve collective
motion in realistic cases. The transition is gradual, and the critical behavior
is qualitatively different from that of the conventional globally coupled
oscillators. The model not only serves as a novel example of non-locally
coupled oscillators, but also provides insights into the role of intrinsic
heterogeneities in living and artificial microfluidic actuators.Comment: 5 pages, 5 figure
The tidal effects on the lithium abundance of binary systems with giant component
We analise the behavior of lithium abundance as a function of effective
temperature, projected rotational velocity, orbital period and eccentricity for
a sample of 68 binary systems with giant component and orbital period ranging
from about 10 to 6400 days. For these binary systems the Li abundances show a
gradual decrease with temperature, paralleling the well established result for
single giants. We have also observed a dependence of lithium content on
rotation. Binary systems with moderate to high rotation present also moderate
to high Li content. This study shows also that synchronized binary systems with
giant component seems to retain more of their original lithium than the
unsynchronized systems. For orbital periods lower than 100 to 250 days,
typically the period of synchronization for this kind of binary systems,
lithium depleted stars seems to be unusual. The suggestion is made that there
is an 'inhibited zone' in which synchronized binary systems with giant
component having lithium abundance lower than a threshold level should be
unusual.Comment: 6 pages, 3 Postscript figures, uses: aa.cls, psfig.st
Quantum feedback control of a solid-state two-level system
We have studied theoretically the basic operation of a quantum feedback loop
designed to maintain the desired phase of quantum coherent oscillations in a
two-level system. Such feedback can suppress the dephasing of oscillations due
to interaction with environment. Prospective experiments can be realized using
metallic single-electron devices or GaAs technology.Comment: 4 pages, 4 figure
Complex transitions to synchronization in delay-coupled networks of logistic maps
A network of delay-coupled logistic maps exhibits two different
synchronization regimes, depending on the distribution of the coupling delay
times. When the delays are homogeneous throughout the network, the network
synchronizes to a time-dependent state [Atay et al., Phys. Rev. Lett. 92,
144101 (2004)], which may be periodic or chaotic depending on the delay; when
the delays are sufficiently heterogeneous, the synchronization proceeds to a
steady-state, which is unstable for the uncoupled map [Masoller and Marti,
Phys. Rev. Lett. 94, 134102 (2005)]. Here we characterize the transition from
time-dependent to steady-state synchronization as the width of the delay
distribution increases. We also compare the two transitions to synchronization
as the coupling strength increases. We use transition probabilities calculated
via symbolic analysis and ordinal patterns. We find that, as the coupling
strength increases, before the onset of steady-state synchronization the
network splits into two clusters which are in anti-phase relation with each
other. On the other hand, with increasing delay heterogeneity, no cluster
formation is seen at the onset of steady-state synchronization; however, a
rather complex unsynchronized state is detected, revealed by a diversity of
transition probabilities in the network nodes
Coupled cavity traveling wave tube with velocity tapering
A coupled cavity traveling wave tube with a velocity taper, which affords beam wave resynchronization and thereby enhances is described. The wave velocity reduction is achieved by reducing the resonant frequencies of the individual resonant cavities as a function of the distance from the electron gun, through changes in internal cavity dimensions. The required changes in cavity dimensions can be accomplished by gradually increasing the cavity radius decreasing the gap length from cavity to cavity. The velocity reduction is carried out without an increase in circuit resistive losses and the upper and lower cut off frequencies are reduced in approximately the same manner
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