摘要:

The annual pattern of black and white births in the Southeastern and Midwestern United States was analyzed for the years 1969 thru 1976. Monthly means for the eight‐year period were obtained individually for 17 states and for black births in the District of Columbia. The states and the district were selected for their large black populations and represent approximately 70% of black births in the USA. The data were analyzed in two ways, with an analysis of variance (the two‐factor mixed design with repeated measures on one factor) and by comparing the confidence intervals for the least‐squares derived Fourier coefficients of a sine curve. In addition, the range was compared between regions and between races and related to latitude. The analyses of variance indicated that statistically significant differences existed between regions and between races. The cosinor‐like method failed to adequately represent the data in most cases. The completely urban black population in the District of Columbia exhibited an annual pattern that was similar to the pattern in neighboring states, states that contained large rural populations. The range in the monthly averages of births was different between regions and between races, and inversely correlated with latitude (with “North”; and “white”; having smaller ranges). Some possible causative factors are briefly reviewed, and the correlation of sperm counts and conceptions offered as a new possibility.

ISSN:0022-1945    

DOI:10.1080/09291018709359949

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In this study we determined the sucrase and maltase activity in rat intestinal rings, cultured over periods up to 48 hrs and sampled every 2 hrs. No self‐sustained circadian rhythm could be demonstrated in this study. The initial rise in the enzyme activity can be explained by the absence of pancreatic protease activity in the in vitro situation.

ISSN:0022-1945    

DOI:10.1080/09291018709359950

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Annual histophysiological changes in the adrenal cortex of free‐living blossomheaded parakeets were studied in relation to the gametokinetic activities in the testes and periodic climatic variables to evaluate possible interrelationship, if any, between these endogenous and exogenous cyclic factors. Observations involving histometry, karyometry and lipid cytochemistry of adrenal cortex along with quantitative estimation of tissue cholesterol demonstrate the annual rhythmic pattern in the activity of adrenocortical tissue with an annual peak in February followed by regressive changes till August. Steady progressive changes towards annual peak occur only after November. Results show that the seasonality of the histophysiological features in the adrenal cortex coincides better with the periodic sexual activities of the bird than with any of the surrounding environmental factors.

ISSN:0022-1945    

DOI:10.1080/09291018709359951

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

To test the hypothesis that an oscillator located outside the suprachiasmatic nuclei (SCN) controls the circadian rhythm of body temperature, we conducted a study with 14 blinded rats, 10 of which receiving a SCN lesion. Body temperature was automatically and continuously recorded for about one month by intraperitoneal radio transmitters. Food intake, drinking and locomotor activity were also recorded. Periodograms revealed that 3 rats with histologically verified total bilateral SCN lesions did not exhibit any circadian rhythmicity. The 7 other rats appeared to have partial lesions. They showed shortening of period and severe amplitude reduction in all functions. Thus, no support was found for the hypothesis of a separate circadian ‘temperature oscillator’ located outside the SCN. Nevertheless, after large partial lesions body temperature showed more persistency than some of the other behavioral rhythms.

ISSN:0022-1945    

DOI:10.1080/09291018709359952

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A detailed series of observations were made throughout the year onin vitrocollections ofSynchytrium endobioticum,the causal agent of wart disease of potato. Each month a fresh sample of the fungus estimated at 10.000 spores per dish was incubated in water. The numbers of resting spores with attached vesicles and numbers of subsequently empty ones were estimated for 22 days each month. The numbers of empty resting spores which accumulated each month varied from month to month, and from week to week in any month. Large numbers of empty spores indicated massive germination. Germination was greatest in the spring/early summer season and late fall/early winter. Vesicle production also varied, and the rates of germination of vesicles varied during the year so that vesicles remained ungerminated longest in winter, and to some extent in sumer and late fall. Vesicle production was greatest on the average by the start of the third week of incubation. The wax and wane of empty spore production explains the tendency of the disease to peak at certain times during the year.

ISSN:0022-1945    

DOI:10.1080/09291018709359953

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Trapping studies ofNeocurtillaandScapleriscusmole crickets in South America and Florida, USA, revealed a latitudinal variation in the flight periodicity of dispersing adults. These data demonstrate that these subterranean insects are able to respond to seasonal cues to optimize their life cycle.

ISSN:0022-1945    

DOI:10.1080/09291018709359954

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A well marked diurnal rhythm of hypothalamic monoamine oxidase (MAO) activity was observed inChanna punctatusin LD 11:13 and ambient temperature (15±1°C) with peak activity at mid‐dark phase. Long photoperiod and higher temperature (16L:8D; 22±1°C) induced a 180° shift in the diurnal pattern of the enzyme activity with significantly raised levels at 7.00 and 12.00 h in the photophase. Melatonin‐induced reduction of MAO activity was significant only in the early and mid‐scotophase under the 11L:13D; 15±1°C regime. However, in the 16L:8D; 22±1°C group, after melatonin administration the enzyme activity was considerably reduced at 7 and 12 h in the photophase as also at late scotophase.

ISSN:0022-1945    

DOI:10.1080/09291018709359955

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

To determine if a circadian response to thyroxine (T4) is exhibited byXenopus laevistadpoles, an experiment was performed in which groups of tadpoles were maintained in thyroxine‐treated or normal water on a 12‐hr photoperiod with a water temperature of approximately 20° C. All the groups were fed daily at the onset of the photoperiod. The thyroxine‐treated tadpoles were in thyroxine‐treated water either during the light or the dark phase of the photoperiod. These tadpoles were moved into and out of the thyroxine‐treated water every 12 hrs. Similarly, control groups were moved into and out of normal water every 12 hrs. Other control groups were maintained in normal water which was changed every 48 hrs. Using tail reabsorption as an index of metamorphosis, it was found that the mean length of the tadpoles was significantly shorter in tadpoles which were exposed to thyroxine during the light phase. According to theNormal Table of Xenopus laevis(Nieuwkoop and Faber, 1975), the tadpoles exposed to thyroxine during the light phase also showed the greatest change in morphology such as limb development.

ISSN:0022-1945    

DOI:10.1080/09291018709359956

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Both instrumentation and computer technologies made possible a real‐time monitoring of clinical problems. Data acquisition is intimately linked to the need for adequate statistical methods. Most of the biostatistical procedures deal with the numerical statistics of discontinuous data series. More recently, computer‐assisted statistics makes affordable the data series analysis using inferential procedures. Analytical statistics is an integral part of the chronobiologic methods used for estimating the biological functions in their periodicity along the time scale. This report is, thus, dealing with a software entirely dedicated to process biodata series by means of the inferential rhythmometry of chronobiology.

ISSN:0022-1945    

DOI:10.1080/09291018709359957

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

In this study, we analyse the temporal organization within the 24‐h period of three different endocrine systems, renin‐angiotensin, insulin and glucose, ACTH and cortisol, which display similar cycles with a period of about 100 min, and examine their relationships to meal intake and to the cyclic alternation of REM‐NREM sleep. The 24‐h profiles were established simultaneously in 6 subjects who had standard meals and in 4 subjects under continuous enterai nutrition. During night‐sleep, plasma renin activity displayed sustained oscillations which were closely related to the REM‐NREM sleep cycles. No systematic relationship was found between the sleep stages and, either the small nocturnal fluctuations in insulin and glucose observed in normally eating subjects, or the sustained oscillations observed in subjects under continuous enterai nutrition. Similarly, the secretory episodes of ACTH and cortisol were not coordinated with the REM‐NREM sleep cycles. During the day‐time, meals amplified ACTH, cortisol and renin release, and thus synchronized the spontaneously occurring fluctuations. Meals also stimulated pancreatic secretion and induced two to five postprandial insulin and glucose peaks, which gave damped oscillatory patterns. No temporal concordance was found between cortisol secretory episodes, and renin or insulin oscillations. The different relationships between the hormonal oscillations and the REM‐NREM sleep cycles, as well as the different effect of meals which either modify the oscillatory patterns or initiate them, suggest that there are wide variations in the processes generating the ultradian endocrine rhythms. Their functional and adaptational significance has yet to be explored.

ISSN:0022-1945    

DOI:10.1080/09291018709359958

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor