摘要:

The analysis of long temporal series of gas exchange of seeds in moist atmosphere or of root lengths of seedlings reveals the existence of non‐random fluctuations. Several observations allow us to envisage the presence of rhythmicities with modulated periods.

ISSN:0022-1945    

DOI:10.1080/09291017809359642

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

The adrenergic agonists and antagonists, norepinephrine, phenylephrine, iso‐proterenol, phentolamine, and propranolol, were administered to rats in different phases of the diurnal cycle, and their effects on tyrosine aminotransferase activity were studied. All substances tested, regardless whether being typicallyα‐orß‐adrenergic or whether being agonists or antagonists, elevated tyrosine aminotransferase during the minimum of enzyme activity. The effects at the enzyme maximum, however, were generally more or less depressive. The extent of the depressions by norepinephrine and by propranolol highly depended on the duration of treatment. The hepatic concentration of cyclic AMP did not exhibit a significant rhythmicity. The results do not favour the idea of an adrenergic control of the diurnal rhythm in tyrosine aminotransferase activity.

ISSN:0022-1945    

DOI:10.1080/09291017809359643

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Drosophila melanogasterwas reared under LD 12:12. Fat body was isolated in form of cells and cell groups from dissected larvae or prepupae by treatment with collagenase and hyaluronidase and subsequent centrifugation. Tyrosine aminotransferase of the fat body showed an extremely sharp pH dependence, with two narrow, well separable maxima at pH 5.6 and 6.0, possibly caused by different isoenzymes. Enzyme activity at pH 5.6 exhibited biphasic circadian rhythms in both wild‐type 3rd instar larvae and early prepupae. At pH 6.0, the rhythmicity was much weaker, perhaps even absent. In larvae from an ebony strain, at either pH the basal tyrosine aminotransferase activity was enhanced, and the rhythmicity was altered.

ISSN:0022-1945    

DOI:10.1080/09291017809359644

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Permanent oestrus was induced in 24, 61 and 100% of 2‐months old Wistar rats under conditions of continuous light exposure (LL) for 1, 2 and 6 months, respectively. After cessation of 2 months LL, rhythmic fluctuations of oestrus activity were observed.

ISSN:0022-1945    

DOI:10.1080/09291017809359645

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Although the physical mechanism of the sunspot cycle is not well‐known, we can adequately predict its behaviour through empirico‐statistical methods. Working on the so‐called areas index Iaof the solar activity (Xanthakis, 1969, 1970; Poulakos and Tritakis, 1972; Tritakis, 1974, 1978) we have defined some useful relations which help to predict various basic parameters of the sunspot cycle and its profile, as well.

ISSN:0022-1945    

DOI:10.1080/09291017809359646

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Annual predictions of global deaths from civil war to the year 2001 have been made based on an earlier two‐stage cyclical model. In stage one three cycles (8.6, 17.4, and 34 yr) predict to changes in the global political system, while four cycles (5.6, 9.4, 20.5, and 54 yr) predict to changes in the global economic system. In stage two, changes in the political and economic systems predict to changes in the level of civil violence. Fifteen regression equations, four tables, and six diagrams are included with the text

ISSN:0022-1945    

DOI:10.1080/09291017809359647

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291017809359641

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor