摘要:

The frequently used cosine as regression function is, in general, not suited for the extrapolation of maximum, minimum, and over‐all mean of rhythmic data, as it is not a priori clear that the rhythm is sinusoidal, and curve‐fitting to non‐sinusoidal data leads to erroneous results.

ISSN:0022-1945    

DOI:10.1080/09291018209359758

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The white sucker,Catostomus commersoni, displays a diel rhythm of behavioural thermoregulation in a horizontal thermal gradient. Under LD 12: 12 single fish select significantly higher temperatures in the scotophase than in the photophase. An endogenous lunar rhythm exists in the absolute and maximum and minimum temperatures selected. Significantly higher temperatures (+2°C) are selected at the times of the new moon than at the times of the full moon. This provides the first demonstration of an endogenous lunar rhythm in the thermoregulatory behaviour of a vertebrate.

ISSN:0022-1945    

DOI:10.1080/09291018209359759

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The levels of histamine in the cerebral cortex, cerebellum, midbrain and caudate nucleus of adult male rats were determined fluorometrically every 3 h over a 24 h period in control animals and in animals injected, 30 min earlier, with 50 mg/kg phenobarbital, 40 mg/kg pentylenetetrazol or 8 mg/kg picrotoxin. All the animals were adapted for at least three weeks to an LD 12: 12 illumination regime. Results show that histamine levels in the brain areas studied, particularly in the caudate nucleus, were highest during the dark phase and lowest during the light phase of the cycle. Phenobarbital, pentylenetetrazol and picrotoxin consistently decreased histamine levels during the dark phase while increasing the levels of histamine during the light phase of the cycle in these brain areas, thus phaseshifting the rhythmic pattern of the amine, particularly in the cerebral cortex and caudate nucleus in the cases of phenobarbital and picrotoxin and in the caudate nucleus in the case of pentylenetetrazol.

ISSN:0022-1945    

DOI:10.1080/09291018209359760

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Several recent biological monitoring systems assess ventilatory rates of fish for judging water and wastewater quality. Applications of various statistical techniques in these biomonitors require that certain assumptions be made about the data base. This paper describes the temporal distribution of the ventilatory frequencies of the bluegrill,Lepomis macrochirus, and discusses the validity of some of the premises associated with such studies.

ISSN:0022-1945    

DOI:10.1080/09291018209359761

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Endogenous circadian rhythms of spontaneous bioluminescence are demonstrated in two recently collected dinoflagellate strains,Pyrocystis elegansstrain ME 8 andPyrocystiscf.acutastrain ME 9. The rhythms freerun in DD for several periods, but are readily damped out in L.L. The emitted light intensity allows measurements in single cells by means of a scintillation spectrometer. With regard to the periodicity of spontaneous bioluminescence, the two species differ from other cultured strains ofPyrocystisspecies such asP. lunulaandP.fusiformis, which only show rhythms of induced bioluminescence.

ISSN:0022-1945    

DOI:10.1080/09291018209359762

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

In two subspecies of mosquito,Culex pipiens pallensandC.p. molestus, kept under LD 16: 8 the evening (E) and the morning (M) peaks of activity responded differently to changes of temperature.Molestusshowed E and M which were phase‐advanced and ‐delayed, respectively, in response to lowering the temperature. In both mosquitoes, the inhibitory effect of low temperature is exerted upon M to a much larger extent than E. These facts suggest, on the one hand, that E and M are of different physiological nature and, on the other, that the circadian system involves some adaptive mechanism to the seasonal change of the daily temperature cycle. It seems too early to conclude, however, that E and M are underlain by separate circadian oscillations.

ISSN:0022-1945    

DOI:10.1080/09291018209359763

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The amplitude of the leaf movement inOxalis acetosellaandOxalis regnelliistrongly depends upon the strength of the Zeitgeber. In this paper the strength of the ZG was lowered by reducing the light‐intensity steps to ratios of 10: 1 (3000: 300 lux) or 4.3: 1 (1300: 300 lux). Under such conditionsO. acetosellaexhibited as little as 15% of its maximal amplitudes in one of the experiments.

ISSN:0022-1945    

DOI:10.1080/09291018209359764

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Measurement of persistent circadian rhythms of bioluminescence in the marine dinoflagellateGonyaulax polyedrahas been automated using the Apple II microcomputer. The mechanics of the system are under software control and allow for the measurement of up to 60 different samples for periods of at least 3 weeks, with data points for each sample every 15 min. Experiments are presented showing that 4‐h exposures to streptimidone, a potent inhibitor of protein synthesis on 80s ribosomes, result in phase shifts in the rhythm.

ISSN:0022-1945    

DOI:10.1080/09291018209359765

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Rubella antibody titers were assayed from 191 blood samples taken during seven years (1973–1979) from a human female who had contracted German measles in 1965. The antibody dilutions, transformed to integers, fit a first‐order harmonic function with an assumed period of 365 days. The levels about which the titers oscillated decreased from 1973 to 1975 and remained stable thereafter. Amplitudes averaged 31% on either side of the level of oscillation. At certain times of the years 1977–1979 at the trough of the rhythm the subject would have been considered to be lacking in immunity against rubella despite history to the contrary. This example of a long‐term, circannual rhythm in an immunologic assay supports previous suggestions that immunity cycles over the seasons.

ISSN:0022-1945    

DOI:10.1080/09291018209359766

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The diurnal excretion patterns of several electrolytes and urea were studied in 5 freely moving rats on an elemental diet (Vivonex) administered either orally or as a continuous intragastric feeding; the lights were on from 07.00–19.00 h and off from 19.00–07.00 h. During continuous feeding the diurnal rhythms persisted, although the amplitude was lower than during oral feeding. The maximum excretion rates of potassium, phosphate and urea all coincided under both feeding regimens. The time of the maximum calcium excretion rate coincided with that of sodium during oral feeding but not during continuous feeding. During continuous feeding the maximum calcium excretion rate shifted from 04.00 to 10.00 h. The diurnal excretion of magnesium during continuous feeding was abolished, possibly as a result of the low calcium intake. From this study it can be concluded that duringcontinuous intragastric feeding all of the studied excretion patterns persist, with the exception of magnesium, which indicates that these rhythms are not merely the result of the intermittent intake of food and minerals.

ISSN:0022-1945    

DOI:10.1080/09291018209359767

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor