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Author Aschoff, J.
Title Circadian Activity Pattern with Two Peaks Type Journal Article
Year (up) 1966 Publication Ecology Abbreviated Journal
Volume 47 Issue 4 Pages 657-662
Keywords Ecology
Abstract The 24-hr rhythms of behavior and other physiological functions are based upon an endogenous self-sustained oscillation. This is proven by experiments in which animals, kept in constant conditions, show a freerunning circadian period which deviates to a certain degree from that of the earth's rotation. The 24-hr rhythms of activity are furthermore characterized by typical patterns of which the one with two peaks in one period is most common. Under natural conditions, these two peaks of activity are often closely related to specific stimuli in the environment; e.g. to dawn and dusk. They have therefore been described as being directly caused by the environment. However, one may consider not only the circadian period but also the pattern part of an endogenous system. This hypothesis has been tested in experiments with finches. The results are: 1) Birds kept in artificial light-dark cycles show the same two-peak pattern either in cycles with interposed twilight or in cycles with rectangular changes between light and dark, 2) Under constant conditions, the second peak may disappear; but more often, it either remains or becomes more pronounced tan under conditions of a light-dark cycle. 3) With different levels of constant intensity of illumination, the birds show different circadian periods and different durations of activity; under those conditions, the two peaks keep the same proportional relationship to the activity time regardless of its duration. It is concluded that the basic two-peak pattern of locomotor activity is a persistent property of the circadian oscillating system.
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Call Number LoNNe @ kagoburian @ Serial 711
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Author Holt, C.S.; Waters, T.F.
Title Effect of Light Intensity on the Drift of Stream Invertebrates Type Journal Article
Year (up) 1967 Publication Ecology Abbreviated Journal Ecology
Volume 48 Issue 2 Pages 225
Keywords Animals
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ISSN 0012-9658 ISBN Medium
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Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 426
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Author Elliott, J.M.
Title The daily activity patterns of mayfly nymphs (Ephemeroptera) Type Journal Article
Year (up) 1968 Publication Journal of Zoology Abbreviated Journal
Volume 155 Issue 2 Pages 201-221
Keywords Animals
Abstract Nymphs of Baëtis rhodani (Pictet), Ephemerella ignita (Poda), Ecdyonurus venosus (Fabricius), Rhithrogena semicolorata (Curtis), and Heptagenia lateralis (Curtis) showed a similar endogenous rhythm of activity under conditions of natural illumination, continuous light and continuous darkness; and were most active at night when they moved from the lower to the upper surface of the stone. The nymphs were positively thigmotactic and negatively phototactic in flowing water, but these taxes and the endogenous activity rhythm of all species except Heptagenia lateralis changed markedly when the flow of water ceased.
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ISSN 0952-8369 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 2467
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Author Waddill, D.G.; Chaney, C.H.; Dutt, R.H.
Title Ovulation Rate In Gilts After Short-Time Exposure To Continuous Light Type Journal Article
Year (up) 1968 Publication Reproduction Abbreviated Journal Reproduction
Volume 15 Issue 1 Pages 123-125
Keywords Animals
Abstract Ovulation rate in gilts maintained under continuous light (daylight plus 118 to 130 lux of artificial light at night) for a complete oestrous cycle during the spring months was not significantly different from that in gilts maintained under normal daylight. Average ovulation rates were 13·4 for controls and 13·1 for treated gilts. A significant (P<0·01) difference in ovulation rate was found between years.
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ISSN 1470-1626 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 2468
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Author BjÖRnberg, T.K.S.; Wilbur, K.M.
Title Copepod Phototaxis And Vertical Migration Influenced By Xanthene Dyes Type Journal Article
Year (up) 1968 Publication The Biological Bulletin Abbreviated Journal The Biological Bulletin
Volume 134 Issue 3 Pages 398-410
Keywords Animals
Abstract 1. Phototaxis of the copepods Paracalanus crassirostris, Calanopia americana, and Acartia lillijeborgi has been measured by determining the percentage of a population moving toward or away from a point source of light per unit time. Quantitative differences in positive phototaxis were found between the species. Photopositive responses differed during the day and night in Acartia but not in Paracalanus and Calanopia.

2. Rhodamine B (8.4 x 10-6 M) brought about the following effects: (a) Locomotor activity was reversibly inhibited in all species. (b) Photopositive responses were increased in Calanopia and Acartia but decreased in Paracalanus. (c) The difference between day and night responses to a point source of light was abolished in Acartia and induced in Calanopia. (d) Somersaulting was induced in Paracalanus but not in the other species.

3. Pyronine B (8.4 x 10-6 M) also decreased locomotor activity. Fluorescein sodium (1.1 x 10-5 M and 1.1 x 10-4 M) was without significant effect.

4. Paracalanus, Calanopia, and Acartia exhibited characteristically distinct diurnal migratory cycles in vertical cylinders, which correlated well with behavior in natural waters. Calanopia and Acartia migrated to the bottom in the daylight whereas Paracalanus and young forms of Acartia were widely distributed vertically during daylight. Specimens of Calanopia and Acartia kept in the dark did not migrate.

5. The effects of rhodamine B (8.4 x 10-6 M) on vertical migration depended upon species, developmental stage, and time of day. In general, rhodamine increased the concentration of animals at the surface at night and at the bottom in daylight. Fluorescein sodium (1.1 x 10-5 M and 1.1 x 10-4 M) had little effect on vertical migration.

6. The effectiveness of rhodamine B and pyronine B is probably related to the presence of diethylamine groups lacking in fluorescein.
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ISSN 0006-3185 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 2469
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