摘要:

Study of the biological rhythms in cavernicoles is of considerable interest especially since the cave ecosystem is characterized by absence of light, relatively constant temperature and relatively high and constant humidity. The present paper documents for the first time multifrequency biologic rhythms in air gulping behaviour of a cavernicolous fishOreonectus evezardi,kept under complete darkness, DD. A circadian rhythm was demonstrated with statistical significance by cosinor method for air‐gulping activity during 9 months out of 14 months of observations. A 6‐monthly rhythm in circadian mesor was detected. However, statistically significant circannual rhythms in circadian amplitude and circadian acrophase were validated. Thus, results of the present study clearly demonstrate semicircannual or circannual modulation of the circadian behavioural rhythm of a cave dwelling teleost.

ISSN:0022-1945    

DOI:10.1080/09291019009360086

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291019009360087

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291019009360088

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291019009360092

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

It was previously shown that rabbits which have been exposed for several weeks to the natural sequence of daylight and nocturnal darkness, or to fixed 24‐h L:D alternations, exhibit afterwards a programmed rhythm in retinal sensitivity to flashes and steady illumination. This rhythm consists of a phase in which the animals steadily respond to flashes with “Day Time Potentials”; (D.T.P.’s) for the ERG's and cortical responses, and a phase with “Night Time Potentials”; (N.T.P.’s) connected with raised photic sensitivity. The rhythm is obliterated by bilateral sectioning of the cervical sympathetic nerve (CSN), after which the responses are constantly of the D.T.P.‐type. It now appears, from a comparison between the programmed fluctuations in the ERG's and cortical V.E.P.’s and their induced changes during low‐frequency stimulation of the CSN's, that the latter contain fibers which discharge rarely, if at all, in the D.T.P.‐phase and fire at the low rates of 2 cps or less during the N.T.P.‐phase ‐ and evoke in this way the circadian rhythm in photic sensitivity. It would also appear that the noradrenaline released by the postganglionic fibers in question acts upon alpha receptors which are probably situated in the inner nuclear layer of the retina. These results give further evidence for the presence in rabbits of a retino‐hypothalamo‐retinal loop with a 24 hours‐delayed feedback.

ISSN:0022-1945    

DOI:10.1080/09291019009360089

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Traditional methods for curve‐fitting are based upon prior assumptions about the form of the underlying patterns, whether regressions are fitted using polynomials, or chronobiological data are fitted using sinusoids.

ISSN:0022-1945    

DOI:10.1080/09291019009360090

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

摘要:

Diurnal rectal temperatures of lactating Holstein cows were utilized in a series of studies involving shade modifications with spray and fan in addition to herd data during winter and summer to derive a physiologic index. Physiologic stress degree hours was the product of hours of rectal temperature greater than 39°C. Rectal temperature of cows in shade averaged 39.5°C for 19.6 hours (774.5°C h) compared to 39.3°C for 12 hours (471.6°C h) for shade with spray. Nighttime rectal temperature of cows in both groups was 38.5°C, but milk production declined significantly for cows in shade only. In a follow‐up study, shade modification with spray and fan eliminated hours of rectal temperature above 39°C while rectal temperature averaged 39.4°C for 12 hours for cows in shade (471.8°C h). Rectal temperature of cows in different stages and intensities of milk production was similar during winter. On a record hot day (41.4°C), diurnal pattern of rectal temperature identified high producing cows in early lactation as the most heat sensitive. Milk production declined significantly with more than 16 hours of rectal temperature greater than 39°C.

ISSN:0022-1945    

DOI:10.1080/09291019009360091

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291019009360085

出版商:Taylor & Francis Group    

年代:1990

数据来源: Taylor