Biology Reference
In-Depth Information
FIGURE 11-26.
Verbose, tabulated summary of the PHASEREF analytical session presented in Figure 11-25. The columns of interest are:
XOVER(up)—the times at which the short-period smoothed series crosses baseline upward.
XOVER(down)—the times at which the short-period smoothed series crosses the baseline downward.
TIME(max)—the times of extremes, which may be maxima or minima.
TAU(up)—times between up-crossings (estimated as the difference between the lines in the first column). For example, 24.4 ¼
42.415 18.015, and so on.
TAU(down)—times between down-crossings (estimated as the difference between the lines in the second column). For example,
23.47 ¼ 53.505 30.035, and so on.
TAU(max)—contains the respective times between maxima and times between minima. For example, 22.9 ¼ 47.65 24.75 and
23.55 ¼ 60.15 36.6.
B. DTRNDANL Followed by Rhythms Analysis
Examples are provided here of analyses of the noisy, nonstationary time
series introduced in Figure 11-15. This time, the series has been
preprocessed to remove trend prior to analysis. This type of
preprocessing may be necessary before the use of spectral analysis
type methods on time series with aggressive trends, because they are
valid only under the assumptions that the time series being analyzed
is trend-free.
E
XERCISE
11-3
Figures 11-31 through 11-34 present the outputs of the procedures
COSIN2NL, FFT-NLLS, and PHASEREF performed on the detrended
