scispace - formally typeset

Topic

Master clock

About: Master clock is a(n) research topic. Over the lifetime, 2949 publication(s) have been published within this topic receiving 35812 citation(s).


Papers
More filters
Journal ArticleDOI
Flaviu Cristian1
TL;DR: A probabilistic method is proposed for reading remote clocks in distributed systems subject to unbounded random communication delays and can achieve clock synchronization precisions superior to those attainable by previously published clock synchronization algorithms.
Abstract: A probabilistic method is proposed for reading remote clocks in distributed systems subject to unbounded random communication delays. The method can achieve clock synchronization precisions superior to those attainable by previously published clock synchronization algorithms. Its use is illustrated by presenting a time service which maintains externally (and hence, internally) synchronized clocks in the presence of process, communication and clock failures.

607 citations

Journal ArticleDOI
04 May 2006-Neuron
TL;DR: The Cre-LoxP system is used to generate whole-animal knockouts of CLOCK and the resultant circadian phenotypes challenge a central feature of the current mammalian circadian clock model regarding the necessity of CLock:BMAL1 heterodimers for clock function.
Abstract: The circadian clock mechanism in the mouse is composed of interlocking transcriptional feedback loops. Two transcription factors, CLOCK and BMAL1, are believed to be essential components of the circadian clock. We have used the Cre-LoxP system to generate whole-animal knockouts of CLOCK and evaluated the resultant circadian phenotypes. Surprisingly, CLOCK-deficient mice continue to express robust circadian rhythms in locomotor activity, although they do have altered responses to light. At the molecular and biochemical levels, clock gene mRNA and protein levels in both the master clock in the suprachiasmatic nuclei and a peripheral clock in the liver show alterations in the CLOCK-deficient animals, although the molecular feedback loops continue to function. Our data challenge a central feature of the current mammalian circadian clock model regarding the necessity of CLOCK:BMAL1 heterodimers for clock function.

400 citations

Journal ArticleDOI
01 Jan 2000-Neuron
TL;DR: The results show that the daily variation in responsiveness of the SCN to phase-shifting agents is manifested at the level of individual neurons, and propose that GABA is an important synchronizer of SCN neurons in vivo.
Abstract: The master clock in the suprachiasmatic nuclei (SCN) is composed of multiple, single-cell circadian clocks. We test the postulate that these individual "clock cells" can be synchronized to each other by the inhibitory transmitter gamma-aminobutyric acid (GABA). For these experiments, we monitored the firing rate rhythm of individual clock cells on fixed multielectrode plates in culture and tested the effects of GABA. The results show that the daily variation in responsiveness of the SCN to phase-shifting agents is manifested at the level of individual neurons. Moreover, GABA, acting through A-type receptors, can both phase shift and synchronize clock cells. We propose that GABA is an important synchronizer of SCN neurons in vivo.

330 citations

Patent
12 Jan 2001
Abstract: A system for bidirectional communication of digital data between a central unit and a remote unit wherein the need for tracking loops in the central unit has been eliminated. The central unit transmitter generates a master carrier and a master clock signal which are used to transmit downstream data to the remote units. The remote units recover the master carrier and master clock and synchronize local oscillators in each remote unit to these master carrier and master clock signals to generate reference carrier and clock signals for use by the remote unit receiver. These reference carrier and clock signals are also used by the remote unit transmitters to transmit upstream data to the central unit. The central unit receiver detects the phase difference between the reference carrier and clock signals from the remote units periodically and adjusts the phase of the master carrier and master clock signals for use by the central unit receiver to receive the upstream data.

284 citations

Journal ArticleDOI
TL;DR: Differences between master and the peripheral clocks suggest that coupling‐induced rigidity in the SCN filters environmental noise to create a robust circadian system.
Abstract: Circadian clocks are endogenous oscillators driving daily rhythms in physiology and behavior. Synchronization of these timers to environmental light–dark cycles (‘entrainment’) is crucial for an organism’s fitness. Little is known about which oscillator qualities determine entrainment, i.e., entrainment range, phase and amplitude. In a systematic theoretical and experimental study, we uncovered these qualities for circadian oscillators in the suprachiasmatic nucleus (SCN—the master clock in mammals) and the lung (a peripheral clock): (i) the ratio between stimulus (zeitgeber) strength and oscillator amplitude and (ii) the rigidity of the oscillatory system (relaxation rate upon perturbation) determine entrainment properties. Coupling among oscillators affects both qualities resulting in increased amplitude and rigidity. These principles explain our experimental findings that lung clocks entrain to extreme zeitgeber cycles, whereas SCN clocks do not. We confirmed our theoretical predictions by showing that pharmacological inhibition of coupling in the SCN leads to larger ranges of entrainment. These differences between master and the peripheral clocks suggest that coupling-induced rigidity in the SCN filters environmental noise to create a robust circadian system.

273 citations

Network Information
Related Topics (5)
Transmission (telecommunications)

171.3K papers, 1.2M citations

69% related
Amplifier

163.9K papers, 1.3M citations

67% related
CMOS

81.3K papers, 1.1M citations

67% related
Communication channel

137.4K papers, 1.7M citations

66% related
Transistor

138K papers, 1.4M citations

65% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202121
202052
201960
201853
201782
201690