scholarly journals LONG-TERM SOLAR VARIABILITY DEDUCED FROM CHANGES IN THE ATMOSPHERIC 14C PRODUCTION RATE

1984 ◽  
Vol 23 (4) ◽  
pp. 475-482
Author(s):  
J. A. Otaola ◽  
G. Zenteno
Keyword(s):  
Spectral Analysis ◽  
Solar Activity ◽  
Production Rate ◽  
Power Spectral Analysis ◽  
Historical Record ◽  
Future Period ◽  
15Th Century ◽  
Power Spectral ◽  
Type Oscillation

A power spectral analysis of the atmospheric 14C production rate (300-1900 AD) has yielded evidence of the existence of supersecular oscillations in solar activity.  The significance and stability of these oscillations is tested by reproducing the historical record.  The results of a projection into a future period show that a new Spörer type oscillation, similar to that occurred in the 15th century, will probably occur again around the year A. D. 2300.

scholarly journals Dynamic aspects for interislet synchronization of oscillatory insulin secretions

1997 ◽  
Vol 272 (6) ◽  
pp. E981-E988 ◽  
Author(s):  
N. K. Yao ◽  
L. W. Chang ◽  
B. J. Lin ◽  
T. S. Kuo
Keyword(s):  
Spectral Analysis ◽  
Glucose Level ◽  
Glucose Concentration ◽  
Cross Correlation ◽  
Power Spectral Analysis ◽  
Step Function ◽  
Sudden Increase ◽  
Physiological Effects ◽  
Power Spectral

How are the oscillatory insulin secretions from numerous islets synchronized to result in an identifiable oscillation? We postulated that a sudden increase in glucose concentration could best account for the interislet synchronization. The perifusion with two parallel chambers each containing 100 islets from the same rat was performed. The glucose concentrations of two chambers were simultaneously increased from 100 to 300 mg/dl in step function to examine the synchronizing efficacy. Synchrony and regularity of insulin oscillation were evaluated by cross-correlation and/or power spectral analysis. Although the insulin had been in stable oscillation, we found that the synchrony between two chambers and the regularity of each chamber were still significantly improved after a sudden increase in glucose level. However, the improved synchrony and regularity were transient. They gradually slid toward a less rigorous condition in a 15-h long-term perifusion. We suggested that the interislet synchronization of oscillatory insulin secretions could be improved by a sudden increase in glucose level. The insulin pulses were therefore enhanced to present their physiological effects.

Usefulness of Power Spectral Analysis for Measurement of Local Muscle Fatigue during Keyboard Task

1999 ◽  
Vol 11 (4) ◽  
pp. 449
Author(s):  
Soon Young Kwon ◽  
Chung Yill Park ◽  
Jung Wan Koo ◽  
Hyeon Woo Yim ◽  
Kang Sook Lee
Keyword(s):  
Spectral Analysis ◽  
Muscle Fatigue ◽  
Power Spectral Analysis ◽  
Power Spectral ◽  
Local Muscle Fatigue

Power spectral analysis of heart rate and blood pressure variability in anaesthetized dogs

1992 ◽  
Vol 146 (2) ◽  
pp. 155-164 ◽  
Author(s):  
A. E. HEDMAN ◽  
J. E. K. HARTIKAINEN ◽  
K. U. O. TAHVANAINEN ◽  
M. O. K. HAKUMÄKI
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Spectral Analysis ◽  
Blood Pressure Variability ◽  
Power Spectral Analysis ◽  
Power Spectral
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