Selection for Phase Angle Difference of the Adult Locomotor Activity in Drosophila rajasekari Affects the Activity Pattern, Free-running Period, Phase Shifts and Sensitivity to Light

1999 ◽  
Vol 30 (1) ◽  
pp. 10-28 ◽  
Author(s):  
D.S. Joshi
Keyword(s):  
Locomotor Activity ◽  
Phase Angle ◽  
Activity Pattern ◽  
Phase Shifts ◽  
Phase Angle Difference ◽  
Angle Difference ◽  
Free Running ◽  
Selection For ◽  
Free Running Period ◽  
Drosophila Rajasekari

Circadian rhythms in the brown bullhead, Ictalurus nebulosus (Teleostei). Evidence for an endogenous rhythm in feeding, locomotor, and reaction time behaviour

1980 ◽  
Vol 58 (10) ◽  
pp. 1899-1907 ◽  
Author(s):  
Lars-Ove Eriksson ◽  
Theo van Veen
Keyword(s):  
Reaction Time ◽  
Locomotor Activity ◽  
Feeding Activity ◽  
Brown Bullhead ◽  
Phase Angle Difference ◽  
Ictalurus Nebulosus ◽  
Angle Difference ◽  
Dark Regime ◽  
Free Running ◽  
Time Latency

Locomotor and feeding activity was investigated under(1) 12 h light(L): 12 h dark(D)and 16 h L: 8 h D, (2) 24 h D and 24 h L, and (3) dark pulses (0.75 h L: 0.25 h D), in the brown bullhead (Ictalurus nebulosus). In addition to locomotor and feeding activity, reaction time (latency time on lights-off and lights-on) was also measured.Fish subjected to a light–dark regime showed nocturnal behaviour, in many cases with a positive phase angle difference (i.e., the animals ceased their activity several hours before lights-on). Further, the actograms showed, as expected, a distinct 24 h rhythm. Only 2 brown bullheads out of 15, subjected to constant conditions, showed a circadian component in the locomotor activity, which could only be detected by frequency analysis.Nine out of 12 animals subjected to dark pulses (0.75 h L: 0.25 h D) showed a free-running circadian rhythm (approximately 23 h) in locomotor activity and 2 out of 3 showed such a rhythm in feeding activity. Observations and measurements of reaction time on leaving and re-entering the shelter after lights-off and lights-on (0.75 h L: 0.25 h D) showed also that this parameter has a circadian course. Measurements performed a fortnight later showed a similar, but less pronounced, pattern of behaviour.Dark pulses are thought to prevent rapid dissociation of a flexible multioscillatory circadian system in the brown bullhead.

Circadian characteristics of Djungarian hamsters: effects of photoperiodic pretreatment and artificial selection

1991 ◽  
Vol 261 (3) ◽  
pp. R670-R676 ◽  
Author(s):  
W. Puchalski ◽  
G. R. Lynch
Keyword(s):  
Phase Angle ◽  
Artificial Selection ◽  
Phase Response Curve ◽  
Circadian Rhythmicity ◽  
Activity Duration ◽  
High Line ◽  
Free Running ◽  
Selection For ◽  
Free Running Period ◽  
Short Days

Bidirectional artificial selection for (High Line) and against (Low Line) photoresponsiveness altered the percent of photoresponsive hamsters within lines and affected circadian function of hamsters identical in photoresponsiveness. For example, free-running period was shorter in responsive relative to nonresponsive hamsters. Between-line differences for responders and nonresponders were also found: hamsters from the High Line had a shorter free-running period relative to Low Line hamsters. However, phase angle of entrainment to long and short days was not affected. In general, expression of circadian rhythmicity was extraordinarily inflexible in photononresponsive hamsters from both lines: 1) phase angle of entrainment to lights on was similar under short and long day; 2) activity duration was similar under long and short days, although some decompression occurred in constant dark; 3) aftereffects on the free-running period were absent; and 4) amplitude of the phase-response curve was small (+/- 1 h) and present only at circadian times 10-24. We propose that selection for or against photoresponsiveness may have affected the interaction of component oscillators underlying circadian rhythmicity.

Effects of aging on entrainment and rate of resynchronization of circadian locomotor activity

1992 ◽  
Vol 263 (5) ◽  
pp. R1099-R1103 ◽  
Author(s):  
P. C. Zee ◽  
R. S. Rosenberg ◽  
F. W. Turek
Keyword(s):  
Circadian Rhythm ◽  
Locomotor Activity ◽  
Activity Rhythm ◽  
Phase Advance ◽  
Middle Aged ◽  
Age Related ◽  
Free Running ◽  
Effects Of Aging ◽  
Free Running Period ◽  
Related Phase

The phase angle of entrainment of the circadian rhythm of the locomotor activity rhythm to a light-dark (LD) cycle was examined in young (2-5 mo old) and middle-aged (13-16 mo old) hamsters. An age-related phase advance in the onset of locomotor activity relative to lights off was seen during stable entrainment to a 14:10-h LD cycle. In addition, the effects of age on the rate of reentrainment of the circadian rhythm of locomotor activity were examined by subjecting young and middle-aged hamsters to either an 8-h advance or delay shift of the LD cycle. Middle-aged hamsters resynchronized more rapidly after a phase advance of the LD cycle than did young hamsters, whereas young hamsters were able to phase delay more rapidly than middle-aged hamsters. The age-related phase advance of activity onset under entrained conditions, and the alteration of responses in middle-aged hamsters reentraining to a phase-shifted LD cycle, may be due to the shortening of the free-running period of the circadian rhythm of locomotor activity with advancing age that has previously been observed in this species.

Neuropeptide F immunoreactive clock neurons modify evening locomotor activity and free-running period in Drosophila melanogaster

2012 ◽  
Vol 520 (5) ◽  
pp. 970-987 ◽  
Author(s):  
Christiane Hermann ◽  
Taishi Yoshii ◽  
Verena Dusik ◽  
Charlotte Helfrich-Förster
Keyword(s):  
Drosophila Melanogaster ◽  
Locomotor Activity ◽  
Free Running ◽  
Neuropeptide F ◽  
Free Running Period

Zur Beziehung zwischen Phasenlage und Spontanfrequenz bei der endogenen Tagesperiodik

1963 ◽  
Vol 18 (2) ◽  
pp. 154-157 ◽  
Author(s):  
Klaus Hoffmann
Keyword(s):  
Phase Angle ◽  
Diurnal Rhythm ◽  
Activity Rhythm ◽  
Sustained Oscillation ◽  
Temperature Cycle ◽  
Biological Processes ◽  
Experimental Demonstration ◽  
Free Running ◽  
Spontaneous Frequency ◽  
Free Running Period

The mechanism underlying the endogenous diurnal periodicity of biological processes can be considered a self-sustained oscillation, which can be entrained to an external cycle. In such oscillations the phase-angle of the entrained cycle depends upon the spontaneous frequency (free-running period) of the oscillator.The activity rhythm of lizards kept in constant light, and in a sinusoidal 24-hour temperature cycle, showed entrainment to this cycle. The phase of the entrained rhythm depended on the spontaneous frequency which was expressed in constant conditions occurring immediately before or after the exposure to the extraneous cycle. This is the first experimental demonstration showing the dependence of phase on the free-running period in an endogenous diurnal rhythm.

scholarly journals Islanding Detection Using a Micro-Synchrophasor for Distribution Systems with Distributed Generation

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5180
Author(s):  
Karthikeyan Subramanian ◽  
Ashok Kumar Loganathan
Keyword(s):  
Distributed Generation ◽  
Phase Angle ◽  
Distribution Systems ◽  
Detection Algorithm ◽  
Rate Of Change ◽  
Islanding Detection ◽  
Phase Angle Difference ◽  
Angle Difference ◽  
Voltage Phase ◽  
Islanded Grid

Distributed Generation (DG) has changed the power generation system to small-scale instead of large-scale generation. The demanding issue with the interconnection of DG is the detection of unintended islanding in a network. Several methods proposed in the literature show drawbacks such as high non-detection zones (NDZ) and higher tripping time. In this paper, the IEEE 13 bus distribution network with DGs like wind and solar power plants is integrated at two buses. Islanding is detected by utilizing data from a micro-synchrophasor located at the distribution grid and the DG. The micro-synchrophasor-based unintended islanding detection algorithm is based on parameters such as voltage, rate of change of voltage, frequency, rate of change of frequency, voltage phase angle difference and the rate of change of the voltage phase angle difference between the utility and the islanded grid. The proposed islanding detection algorithm discriminates between islanding and non-islanding conditions and is highly efficient under zero power mismatch conditions. The proposed method has null NDZ and satisfies the IEEE 1547 standard for DG tripping time. The effectiveness of the proposed IDM was verified when there are multiple DGs in the islanded grid. Also, the proposed method does not require additional hardware as it can be incorporated in digital relays with synchrophasor functionality.

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