The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Chenglin Xu - One of the best experts on this subject based on the ideXlab platform.

  • Phase Relationship between polar faculae and sunspot numbers revisited wavelet transform analyses
    Publications of the Astronomical Society of Japan, 2013
    Co-Authors: L H Deng, Zhongquan Qu, Chenglin Xu
    Abstract:

    Cross-correlation analysis and wavelet transform methods are proposed to investigate the Phase Relationship between the polar faculae (PF) and the sunspot numbers (SNs). It was found that: (1) the PF begin 52 months earlier than the SNs on the average of the considered time interval, which should lead to Phase asynchrony between them; (2) the length of the Schwabe cycle for the PF obviously differs from that for the SNs at all time points, and the mean length of the Schwabe cycle of the PF (10.28 yr) is slightly smaller than that of the SNs (10.37 yr); (3) the Phase Relationship between the PF and the SNs is not only time-dependent but also frequency-dependent.

L H Deng - One of the best experts on this subject based on the ideXlab platform.

  • Phase Relationship between polar faculae and sunspot numbers revisited wavelet transform analyses
    Publications of the Astronomical Society of Japan, 2013
    Co-Authors: L H Deng, Zhongquan Qu, Chenglin Xu
    Abstract:

    Cross-correlation analysis and wavelet transform methods are proposed to investigate the Phase Relationship between the polar faculae (PF) and the sunspot numbers (SNs). It was found that: (1) the PF begin 52 months earlier than the SNs on the average of the considered time interval, which should lead to Phase asynchrony between them; (2) the length of the Schwabe cycle for the PF obviously differs from that for the SNs at all time points, and the mean length of the Schwabe cycle of the PF (10.28 yr) is slightly smaller than that of the SNs (10.37 yr); (3) the Phase Relationship between the PF and the SNs is not only time-dependent but also frequency-dependent.

  • Phase Relationship between polar faculae and sunspot numbers
    Proceedings of the International Astronomical Union, 2012
    Co-Authors: L H Deng
    Abstract:

    Linear and nonlinear approaches are used to investigate the Phase asynchrony between the polar faculae (PF) and sunspot numbers (SNs). It is found that, (1) PF show leads of 52 months relative to SNs on the average of the considered time interval; (2) the cross-wavelet transform analysis shows that they are asynchronous in both the low- and high-frequency components. These indicate that their Phase Relationship is not only time-dependent but also frequency-dependent.

C W J Beenakker - One of the best experts on this subject based on the ideXlab platform.

Charles A Czeisler - One of the best experts on this subject based on the ideXlab platform.

  • intrinsic period and light intensity determine the Phase Relationship between melatonin and sleep in humans
    Journal of Biological Rhythms, 2005
    Co-Authors: Kenneth P Wright, Claude Gronfier, Jeanne F Duffy, Charles A Czeisler
    Abstract:

    The internal circadian clock and sleep-wake homeostasis regulate the timing of human brain function, physiology, and behavior so that wakefulness and its associated functions are optimal during the solar day and that sleep and its related functions are optimal at night. The maintenance of a normal Phase Relationship between the internal circadian clock, sleep-wake homeostasis, and the light-dark cycle is crucial for optimal neurobehavioral and physiological function. Here, the authors show that the Phase Relationship between these factors—the Phase angle of entrainment (ψ)—is strongly determined by the intrinsic period (τ) of the master circadian clock and the strength of the circadian synchronizer. Melatonin was used as a marker of internal biological time, and circadian period was estimated during a forced desynchrony protocol. The authors observed Relationships between the Phase angle of entrainment and intrinsic period after exposure to scheduled habitual wakefulness-sleep light-dark cycle conditions ...

  • Intrinsic period and light intensity determine the Phase Relationship between melatonin and sleep in humans
    Journal of Biological Rhythms, 2005
    Co-Authors: Kenneth P Wright, Claude Gronfier, Jeanne F Duffy, Charles A Czeisler
    Abstract:

    The internal circadian clock and sleep-wake homeostasis regulate the timing of human brain function, physiology, and behavior so that wakefulness and its associated functions are optimal during the solar day and that sleep and its related functions are optimal at night. The maintenance of a normal Phase Relationship between the internal circadian clock, sleep-wake homeostasis, and the light-dark cycle is crucial for optimal neurobehavioral and physiological function. Here, the authors show that the Phase Relationship between these factors—the Phase angle of entrainment (ψ)—is strongly determined by the intrinsic period (τ) of the master circadian clock and the strength of the circadian synchronizer. Melatonin was used as a marker of internal biological time, and circadian period was estimated during a forced desynchrony protocol. The authors observed Relationships between the Phase angle of entrainment and intrinsic period after exposure to scheduled habitual wakefulness-sleep light-dark cycle conditions inside and outside of the laboratory. Individuals with shorter circadian periods initiated sleep and awakened at a later biological time than did individuals with longer circadian periods. The authors also observed that light exposure history influenced the Phase angle of entrainment such that Phase angle was shorter following exposure to a moderate bright light (~450 lux)–dark/wakefulness-sleep schedule for 5 days than exposure to the equivalent of an indoor daytime light (~150 lux)–dark/wakefulness-sleep schedule for 2 days. These findings demonstrate that neurobiological and environmental factors interact to regulate the Phase angle of entrainment in humans. This finding has important implications for understanding physiological organization by the brain’s master circadian clock and may have implications for understanding mechanisms underlying circadian sleep disorders.

Gretchen K. Campbell - One of the best experts on this subject based on the ideXlab platform.

  • Interferometric Measurement of the Current-Phase Relationship of a Superfluid Weak Link
    Physical Review X, 2014
    Co-Authors: Stephen Eckel, Fred Jendrzejewski, Avinash Kumar, Christopher Lobb, Gretchen K. Campbell
    Abstract:

    Weak connections between superconductors or superfluids can differ from classical links due to quantum coherence, which allows flow without resistance. Transport properties through such weak links can be described with a single function, the current-Phase Relationship, which serves as the quantum analog of the current-voltage Relationship. Here, we present a technique for inteferometrically measuring the current-Phase Relationship of superfluid weak links. We interferometrically measure the Phase gradient around a ring-shaped superfluid Bose-Einstein condensate (BEC) containing a rotating weak link, allowing us to identify the current flowing around the ring. While our BEC weak link operates in the hydrodynamic regime, this technique can be extended to all types of weak links (including tunnel junctions) in any Phase-coherent quantum gas. Moreover, it can also measure the current-Phase Relationships of excitations. Such measurements may open new avenues of research in quantum transport.

  • Direct measurement of the current-Phase Relationship of a superfluid weak link
    arXiv: Quantum Gases, 2014
    Co-Authors: Stephen Eckel, Fred Jendrzejewski, Avinash Kumar, Christopher Lobb, Gretchen K. Campbell
    Abstract:

    Weak connections between superconductors or superfluids differ from classical links due to quantum coherence, which allows flow without resistance. Transport properties through such weak links can be described with a single function, the current-Phase Relationship, which serves as the quantum analog of the current-voltage Relationship. Here, we present the first direct measurement of a current-Phase Relationship for a superfluid weak link. We interferometrically measure the Phase gradient around a ring-shaped superfluid Bose-Einstein condensate containing a rotating weak link, allowing us to identify the current flowing around the ring. This technique can be extended to weak links in any Phase-coherent quantum gas and can also measure the current-Phase Relationships of excitations, such as solitonic-vortices. Such measurements may open new avenues of research in quantum transport.