摘要:

In order to investigate whether an alteration in experimental design would affect an apparent circadian rhythm in response of the rat testes to gonadotropins, two protocols were tested using prolactin plus LH or hCG. Time‐Variable Design: the time intervals between hypophysectomy, gonadotropin injection and autopsy were not held constant. Autopsy occurred 24 h after the morning treatment but 12 h following the evening treatment. Time‐Constant Design: all time intervals between procedures were a constant 24 h. Sex accessory tissue weights and serum testosterone were determined to assess responses. Our results show that a particular design (Time‐Variable) results in an apparent circadian response to LH and hCG when this periodicity is not actually present.

ISSN:0022-1945    

DOI:10.1080/09291018609359899

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The constraints of analyzing human circadian rhythm data has led to the introduction of non‐traditional crosscorrelation techniques. One such technique involves calculating the area formed by two circadian rhythms in a state plane. Assuming a cosine model for the rhythms, the area can be converted to a phase angle. To account for irregular rhythms, this technique was expanded from the simple two parameter cosine model to more complex three‐parameter and six‐parameter cosine models. The technique was applied to three examples, to show its usefulness in calculating phase shifts for infrequent, irregular data, for which traditional crosscorrela tion is unsuitable.

ISSN:0022-1945    

DOI:10.1080/09291018609359900

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The circadian chloroplast migration inAcetabularia mediterraneawas monitored by continuously measuring the transmission of the cells near the apex. Under continuous red light the amplitude of the rhythm decreased rapidly within a few days. However, circadian changes of chloroplast density were still detectable even after 28 days of red light, indicating the persistence of the rhythm. When blue light was added after red light preirradiation of several days phase shifts were observed which were expressed as advances as well as delays. The period of the rhythm proved to be strongly dependent on the intensity of the continuous blue light which was given in addition to red light. Different red light intensities did not change the period. The occurrence of both effects indicates that the sensory transduction of blue light photoreception inAcetabulariaworks in two different ways: quanta counting processes and processes of light intensity measurement.

ISSN:0022-1945    

DOI:10.1080/09291018609359901

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The purpose of our study was to investigate the possibility of revealing hitherto concealed genetic variation in the laying capacity of the domestic hen. Usually, a laying hen has an oviposition period slightly longer than 24 h (Fraps, 1970; Yoo et al., 1979), although some birds are capable of laying more often than once every day (Yoo et al., 1979; Foster, 1981). In normal circumstances, hens are synchronized by the driving light‐dark cycle and are inhibited from exhibiting fully their innate capacity of ovulation and oviposition. With a short enough cycle the potential for possible rapid layers could be realized. We therefore screened hens for their ability to adapt their ovipositions to a 231/2‐h cycle. The results showed a considerable variation in laying patterns and exposed hens having a faster than 24‐h ovulation/laying interval. Our method gives a more accurate ranking of hens having a superior ovulation rate, and is thus of value in selection for egg production.

ISSN:0022-1945    

DOI:10.1080/09291018609359902

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

In consideration of the possibility that the close correspondence between the lunar day and the reported average length of man's free‐running circadian rhythm is not, from an evolutionary point of view, entirely coincidental (even though the moon does not appear to function as Zeitgeber to subjects in temporal isolation), the present article calculates the length of the lunar and solar days back to some 1.3·109years ago. While it is shown that on the average the lunar day in absolute, atomic clock hours decreases roughly 40 min for every 108years we trace it back, it is also shown that the lunar day has in every epoch been approx. 31/2% longer than the solar day: roughly the same value by which the average length of man's free‐running circadian rhythms presently exceeds the solar day. Possible evolutionary effects of tidal forces to account for the 3 1/4% correspondence are briefly considered.

ISSN:0022-1945    

DOI:10.1080/09291018609359903

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018609359904

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018609359905

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018609359906

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018609359898

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor