摘要:

A model is presented for calculation of daily courses of main ecological parameters, viz., amount of photosynthetically active radiation, air temperature and soil temperature on slopes and on the horizontal surface. The model is based on the energy balance equation of vegetated surface using the “force restore method”; developed independently by Bhumralkar (1975) and by Blackadar (1976). In it the following meteorological variables are included: solar radiation, cloudiness, temperature of clouds, soil temperature and soil moisture.

ISSN:0022-1945    

DOI:10.1080/09291018109359750

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

We illustrate the use of a two‐time scales (singular perturbations) method for the construction and stability analysis of limit cycle operation in a model‐problem for the time evolution of a spruce budworm population when diffusion and advection processes compete with time‐delays.

ISSN:0022-1945    

DOI:10.1080/09291018109359751

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Oscillatory plant transpiration has been observed in numerous plants, and it is now believed to be a common rather than an exceptional phenomenon. It is related directly to cyclic variations of stomatal aperture and indirectly to the water content of guard, subsidiary and mesophyll cells. A hydraulic‐elastic model of the water transport has been formulated in 1972 in terms of an electric analogue circuit. Subsequent experimental data appear to be inconsistent with the simulated results. The mechanism responsible for the oscillations is analyzed and a modification of the model is proposed. A possible raison d'être of the oscillations is suggested.

ISSN:0022-1945    

DOI:10.1080/09291018109359752

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The Piccardi P test is a method to evaluate the difference between the sedimentation rate of a colloid under a copper screen and in open air. Three different sets of daily test values, collected in Florence in the period 1955–1972, have been considered. Each set has been analyzed with a 5 component Fourier expansion, varying the T period of the maximum component between 6 and 300 months. The best agreement between experimental and theoretical data has been obtained for T = 12 years. Repeating the computation with a 10 component expansion, this value is modified to T = 22.5 years, and another optimum fit at T = 24 years. Those results confirm the Piccardi hypothesis about the connection between the solar cycle and the P test trend. Further confirmation has been obtained by comparing the Wolf sunspot number trend for the period 1954–1974 with the T values obtained by separately analyzing the periods 1955–1966 and 1966–1972. Amore detailed analysis of the short period components stresses the importance of seasonal and annual components.

ISSN:0022-1945    

DOI:10.1080/09291018109359753

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The circadian rhythm in the flight activity of a tropical microchiropteran batTaphozous melanopogonresponds at all phases with delay phase shifts to single light‐on steps (DD/LL transfers). The circadian rhythm responds at all phases with advance phase shifts to single light‐off steps (LL/DD transfers). Phase shifts were measured from the delays or advances of the onsets of flight activity on days following DD/LL and LL/DD transfers relative to the temporal course of the onsets of activity in controls. The magnitude of the phase shifts was a function of the phases in which the transfers were made. The On‐PRC and Off‐PRC plotted from such data are mirror‐images in their time‐course and wave‐form.

ISSN:0022-1945    

DOI:10.1080/09291018109359754

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The period length of the locomotor activity rhythm ofDrosophila melanogasterwild form is under conditions of continuous weak red light 23.38 h, whereas die eye mutants Ly3 with a 23.71 h mean period and JK 84 with 23.14 h differ significantly. This might be due to a changed perception of light and not the result of a change in the circadian pacemaker by the mutation.

ISSN:0022-1945    

DOI:10.1080/09291018109359755

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018109359756

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018109359749

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor