Tatsuo Urabe

An energetic study of the evolution of the terrestrial and Cytherean atmospheres

Abstract Based upon a gray atmosphere model, energy budget at the surface, and the accompanying partition of H 2 O and CO 2 among the atmosphere, the hydrosphere and the lithosphere are studied for terrestrial-type planets. Owing to the effect of the infrared absorption of H 2 O and CO 2 , there exists a critical level of the incoming energy flux to separate the equilibrium surface temperature into low ( 400°K). The former is quasistable while the latter is absolutely stable. The above results are applied to the discussion of secular variations in the states of the terrestrial and Cytherean atmospheres.

A preliminary model to simulate the effect of insecticides on a spider-leafhopper system in the paddy field

On the basis of life-table studies of the green rice leafhopper,Nephotettix cincticeps Uhler, a descriptive model was constructed to simulate the life system of leafhoppers in the paddy field. Computer simulation demonstrated the existence of an optimum ratio of predators to prey in utilization of spiders for the control of leafhoppers. Also the population density ofLycosa which prey upon leafhoppers appears to determine the feasibility of controlling leafhoppers with reduced number of applications of selective insecticides. The increase of leafhoppers after application of non-selective insecticides was also simulated by the proposed model.