Periodogram Analysis and Continuous Spectra

Biometrika ◽  
1950 ◽  
Vol 37 (1/2) ◽  
pp. 1 ◽  
Author(s):  
M. S. Bartlett
Keyword(s):  
Periodogram Analysis

scholarly journals Multifrequential periodogram analysis of earthquake occurrence: An alternative approach to the Schuster spectrum, with two examples in central California

2015 ◽  
Vol 120 (12) ◽  
pp. 8494-8515 ◽  
Author(s):  
Pierre Dutilleul ◽  
Christopher W. Johnson ◽  
Roland Bürgmann ◽  
Yongge Wan ◽  
Zheng‐Kang Shen
Keyword(s):  
Earthquake Occurrence ◽  
Central California ◽  
Alternative Approach ◽  
Periodogram Analysis

scholarly journals Searching for planetary signals in Doppler time series: a performance evaluation of tools for periodogram analysis

2017 ◽  
Vol 468 (4) ◽  
pp. 3775-3784 ◽  
Author(s):  
Matteo Pinamonti ◽  
Alessandro Sozzetti ◽  
Aldo S. Bonomo ◽  
Mario Damasso
Keyword(s):  
Time Series ◽  
Performance Evaluation ◽  
Periodogram Analysis ◽  
A Performance

The accretion process in the magnetic Herbig Ae star HD 104237

2018 ◽  
Vol 14 (A30) ◽  
pp. 137-137
Author(s):  
Markus Schöller ◽  
Mikhail A. Pogodin
Keyword(s):  
Rotation Period ◽  
Primary Component ◽  
Stellar Rotation ◽  
Spectroscopic Parameters ◽  
Disk Wind ◽  
Accretion Process ◽  
Emission Line Spectrum ◽  
Spectroscopic Signatures ◽  
Periodogram Analysis ◽  
Magnetospheric Accretion

AbstractAfter successfully retrieving the known rotation period P = 42.076 d in the Herbig Ae star HD 101412 using spectroscopic signatures of accretion tracers (Schöller et al.2016), we have studied magnetospheric accretion in the Herbig Ae SB2 system HD 104237 using spectroscopic parameters of the He i 10830, Paγ, and He i 5876 lines, formed in the accretion region. Employing 21 spectra obtained with ISAAC and X-shooter, we found that the temporal behavior of these parameters can be explained by a variable amount of matter being accreted in the region between the star and the observer. Using a periodogram analysis, we examined the possible origin of the accretion flow in HD 104237 and considered the following four scenarios: matter flows from the circumbinary envelope, mass exchange between the system’s components, magnetospheric accretion (MA) from the disk onto the star, and fast high-latitude accretion from a disk wind onto a weakly magnetized star. Based on a correlation analysis, we were able to show that the primary component is responsible for the observed emission line spectrum of the system. Since we do not find any correlation of the spectroscopic parameters with the phase of the orbital period (P ≍ 20 d), we can reject the first two scenarios. We found a variation period of about 5 d, which likely represents the stellar rotation period of the primary and favors the MA scenario.

Latitude Dependent Circadian Rhythms of Carabid Beetles

1986 ◽  
Vol 41 (9-10) ◽  
pp. 935-945
Author(s):  
Gisela Leyk ◽  
Wolfgang Martin
Keyword(s):  
Time Course ◽  
Activity Patterns ◽  
Carabid Beetles ◽  
Constant Darkness ◽  
Spectrum Estimation ◽  
Program System ◽  
Central European ◽  
Light Pulses ◽  
Different Types ◽  
Periodogram Analysis

Abstract Comparative studies of circadian activity rhythms were performed with three stocks of the species Pterostichus rhaeticus Heer (from Southern Europe, Central Europe, and the Subarctic) and with one Central European stock of the sibling species Pterostichus nigrita Paykull. The hehaviour was investigated in various LD conditions, constant conditions including LL with changes of the illumination intensity and constant darkness with light pulses. The data were analysed with the program system “Timesdia” containing various techniques like power spectrum estimation, periodogram analysis and complex demodulation. This allowed to reveal the time course of rhythms and to determine the number of phase jumps as a measure for precision. With the help of these methods, the activity patterns are classified in different types of behaviour: synchronization, temporarily synchronization, aperiodic behaviour, free run, temporarily free run, relative entrainment, and relative coordination. Besides graduated differences between the populations in south-to-north direction (e.g. in the tendency to rhythmic behaviour) the analysis revealed splitting of rhythms into two or even three components of different frequencies and transitions from rhythmic to aperiodic behaviour or vice versa after arbitrarily chosen light pulses in constant darkness. This behaviour cannot be explained by a system which is composed of one single limit cycle oscillator, but the results rather support a multi-oscillator model.

scholarly journals Telling the Time with a Broken Clock: Quantifying Circadian Disruption in Animal Models

Biology ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 18 ◽  
Author(s):  
Laurence Brown ◽  
Angus Fisk ◽  
Carina Pothecary ◽  
Stuart Peirson
Keyword(s):  
Circadian Rhythms ◽  
Light Exposure ◽  
Circadian Disruption ◽  
Jet Lag ◽  
Light Phase ◽  
Potential Therapeutic Target ◽  
Normal Ranges ◽  
Activity Onset ◽  
Periodogram Analysis ◽  
Phase Activity

Circadian rhythms are approximately 24 h cycles in physiology and behaviour that enable organisms to anticipate predictable rhythmic changes in their environment. These rhythms are a hallmark of normal healthy physiology, and disruption of circadian rhythms has implications for cognitive, metabolic, cardiovascular and immune function. Circadian disruption is of increasing concern, and may occur as a result of the pressures of our modern 24/7 society—including artificial light exposure, shift-work and jet-lag. In addition, circadian disruption is a common comorbidity in many different conditions, ranging from aging to neurological disorders. A key feature of circadian disruption is the breakdown of robust, reproducible rhythms with increasing fragmentation between activity and rest. Circadian researchers have developed a range of methods for estimating the period of time series, typically based upon periodogram analysis. However, the methods used to quantify circadian disruption across the literature are not consistent. Here we describe a range of different measures that have been used to measure circadian disruption, with a particular focus on laboratory rodent data. These methods include periodogram power, variability in activity onset, light phase activity, activity bouts, interdaily stability, intradaily variability and relative amplitude. The strengths and limitations of these methods are described, as well as their normal ranges and interrelationships. Whilst there is an increasing appreciation of circadian disruption as both a risk to health and a potential therapeutic target, greater consistency in the quantification of disrupted rhythms is needed.

The endogenous locomotor activity rhythm of four supralittoral peracarid crustace

1983 ◽  
Vol 63 (2) ◽  
pp. 481-492 ◽  
Author(s):  
John A. Williams
Keyword(s):  
Locomotor Activity ◽  
Activity Rhythm ◽  
Circadian Pattern ◽  
Crustacean Species ◽  
Emergence Pattern ◽  
Locomotor Activity Rhythm ◽  
Talitrus Saltator ◽  
Locomotor Rhythms ◽  
Endogenous Component ◽  
Periodogram Analysis

The ‘strength’ of the endogenous locomotor activity rhythm of four peracarid crustacean species, denned by the precision and persistence of the rhythm, was examined with particular reference to a ‘burrowing’ versus epifaunal supralittoral life-style. The ‘strength’ of the endogenous component of the activity rhythm was also illustrated using a modified periodogram analysis. In all species, the talitrid amphipods Talitrus saltator, Talorchestia deshayesi, Orchestra gammarella and the oniscoid isopod Ligia oceanica, the laboratory-monitored rhythm and the field emergence pattern displayed a nocturnal, circadian pattern with no clear evidence of any circa-tidal influence. The precision and particularly the persistence of the rhythm of the sand-shore burrowing species T. saltator and T. deshayesi are especially well developed, although a ‘strong’ endogenous component is present in the rhythm of all four species. The significance of the endogenous locomotor rhythms is considered with respect to the supralittoral ecology of the species.

scholarly journals Window Length Selection of Singular Spectrum Analysis and Application to Precipitation Time Series

2017 ◽  
Vol 19 (2) ◽  
pp. 306-317 ◽  
Keyword(s):  
Time Series ◽  
Spectrum Analysis ◽  
Singular Spectrum Analysis ◽  
Precipitation Data ◽  
Window Length ◽  
Analysis Method ◽  
Precipitation Time Series ◽  
Singular Spectrum ◽  
Periodogram Analysis ◽  
Selection Of

Window length is a very critical tuning parameter in Singular Spectrum Analysis (SSA) technique. For finding the optimal value of window length in SSA application, Periodogram analysis method with SSA for referencing on the selection of window length and confirm that the periodogram analysis can provide a good option for window length selection in the application of SSA. Several potential periods of Florida precipitation data are firstly obtained using periodogram analysis method. The SSA technique is applied to precipitation data with different window length as the period and experiential recommendation to extract the precipitation time series, which determines the leading components for reconstructing the precipitation and forecast respectively. A regressive model linear recurrent formula (LRF) model is used to discover physically evolution with the SSA modes of precipitation variability. Precipitation forecasts are deduced from SSA patterns and compared with observed precipitation. Comparison of forecasting results with observed precipitation indicates that the forecasts with window length of L=60 have the better performance among all. Our findings successfully confirm that the periodogram analysis can provide a good option for window length selection in the application of SSA and presents a detailed physical explanation on the varying conditions of precipitation variables.

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