Exercise 42 Detecting rhythmicity in a data set

This exercise uses the program Rhythm to detect rhythmicity in various data sets. As explained in Section 3.3, the program uses the chi square periodogram procedure to evaluate the presence of statistically significant rhythmicity. FIGURE 4.62 Ups and downs in Chicago. The graph shows the mean daily temperature in Chicago (Illinois) from January 1999 to January 2003. There is a clear annual rhythm with higher temperatures in the summer and lower temperatures in the winter. (Source National...

Research On Organs Cells And Molecules

Research at the level of whole organisms is necessary but not sufficient to understand the mechanisms of circadian rhythmicity. Researchers conduct a great deal of research at the level of individual organs, cells, and even molecules inside a cell. Before I discuss some of the techniques used Not at all dependent Slightly dependent Fairly dependent Very dependent Not at all alert Slightly alert Fairly alert Very alert Seldom or never later Less than one hour later 1-2 hours later More than 2...

Chi Square Periodogram Procedure

This exercise uses the program Tau to calculate the period of circadian rhythms using the chi square periodogram procedure described in Section 3.3. The program requires equally spaced data points in a data file without time tags. 1. Double-click on the Circadian icon to open the program banner, then click on Tau (the eighth icon from the left). 2. Note that there are five panels the Source panel (where you identify the file to be analyzed, as in previous programs), the Data panel (where you...

Info

A For common English equivalents of scientific species names, refer to the Organisms Used appendix at the end of the book. b The acrophase is given as number of hours after lights-on (sunrise) for animals maintained under a light-dark cycle with 12 hours of light and 12 hours of darkness per day. c Refer to Literature Cited section of this chapter. a For common English equivalents of scientific species names, refer to the Organisms Used appendix at the end of the book. b The acrophase is given...

Informa

Taylor & Francis Group is the Academic Division of Informa plc. Visit the Taylor & Francis Web site at http www.taylorandfrancis.com and the CRC Press Web site at http www.crcpress.com About the Software Chapter 1 Early Research on Orcadian 1.1 Remote 1.2 20th 1.4 Ethics of Animal Suggestions for Further Web Sites to Literature Chapter 2 Research Methods in Orcadian 2.1 The Scientific 2.2 Research on Populations and 2.3 Research on Organs, Cells, and 2.4 Research on the Suggestions for...

Research On Populations And Organisms

Research in circadian physiology usually involves one or more of four major categories of experimental procedures recording, stimulation, lesioning, and transplantation Figure 2.16 . Recording a physiological variable is the sim- FIGURE 2.16 Research methods in physiology. Research on the vital processes of living organisms always involves one or more of four basic methods recording, stimulation, lesioning, and transplantation. FIGURE 2.16 Research methods in physiology. Research on the vital...

Tidal Rhythms

Circatidal Rhythm

Many organisms live in the interface between ocean and land and, therefore, are affected by the cycle of tides Figure 4.17 . Because tides have existed for millions of years, some species have evolved endogenous circatidal rhythmicity as an adaptive mechanism to react in advance to the regular environmental changes produced by the tides. Debate continues about the existence of a specific circatidal clock distinct from the circadian clock as opposed to a single clock that serves both functions ,...

Enright Periodogram

FIGURE 3.29 Calculation of circadian period by the Enright periodogram. The Enright periodogram procedure and the calculation of circadian period using the modulo adjustment of actograms procedure operate on the same principle. The difference between the two methods is that the Enright periodogram procedure provides a numerical value for the strength of each potential period bottom row . peak is seen when the modulo matches the period of the rhythm. To avoid human subjectivity in determining...