Exercise 41 Hamster estrous cycle
The estrous cycle of the female golden hamster is a good example of an infradian rhythm. When maintained under a light-dark cycle with 14 hours of light per day LD 14 10 , the female hamster exhibits a very regular estrous cycle that repeats itself every 4 days. A convenient variable for monitoring the stages of the cycle is vaginal mucus secretion. For this exercise, you will need one or more female golden hamsters housed individually under LD 14 10. Inspect the vaginal secretion once a day...
Info Iuc
FIGURE 4.29 Watch the road Highway traffic accidents in the United States show a weekly rhythm. Accidents are more common on Fridays and Saturdays than on other days of the week. The solid line shows the percentage of weekly accidents by day of the week as averaged for the years 1995 through 1999. The dashed lines indicate the 95 confidence intervals for the means. Source National Center for Statistics and Analysis, U.S. Department of Transportation. FIGURE 4.29 Watch the road Highway traffic...
Other Infradian Rhythms
A curious infradian rhythm that does not fit into any of the categories discussed in the previous section involves the Canadian lynx Lynx canadensis and the Arctic hare Lepus arcticus , both shown in Figure 4.34. The lynx is hunted commercially for its fur, and good records of fur returns have been kept since the early 1800s. As shown in Figure 4.35, fur returns exhibit a remarkably regular 10-year rhythm. The cause of the rhythm is not fully known, but it is related to a rhythm in the size of...
Literature Cited 1
1. Koertge, N. Ed. 1998 . A House Built on Sand Exposing Postmodernist Myths about Science. New York Oxford University Press. 2. Patai, D. 1998 . Heterophobia Sexual Harassment and the Future of Feminism. Lanham, MD Rowman and Littlefield. 3. Gross, P. R. amp Levitt, N. 1994 . Higher Superstition The Academic Left and Its Quarrels with Science. Baltimore, MD Johns Hopkins University Press. 4. Golinski, J. 1998 . Making Natural Knowledge Constructivism and the History of Science. New York...
Modulo Changes In An Actogram
This exercise demonstrates a simple graphical procedure for determining the period of a rhythm. 2. In the Source panel, select the Data subfolder by double-clicking on it. 3. Select the data file A06 by clicking on it. As mentioned in the preceding exercise, this file contains the locomotor activity records of a pill bug, measured with an infrared photocell for 19 days in constant darkness. The data resolution is 6 minutes, and the file contains no time tags. 4. Click on the Actogram button the...
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
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...
Info Szl
FIGURE 3.42 Just like a c2. The QP statistic of the chi square periodogram is distributed as c2 when the data set contains 10 or more days K gt 10 . In all four panels, the curve for c2 is the probability density curve for 20 degrees of freedom, and the curve for QP is the relative frequency curve based on computations for the period of 21 data points on 10,000 sets of random numbers. FIGURE 3.42 Just like a c2. The QP statistic of the chi square periodogram is distributed as c2 when the data...
Enright Periodogram
FIGURE 3.41 What do probability density curves look like These figures show the probability density curves of three commonly used statistics. Multiple probability density curves exist for the c2 statistic and the F statistic. Only a few of these curves are shown. distribution. It does not care whether there is a single daily peak as is the case for the data set in Panel A of Figure 3.40 or many daily peaks. With an ANOVA, you cannot determine whether the rhythmicity is circadian or ultradian....