House Musk Shrews (Suncus murinus) Do Not Copulate in the Light Period when First Paired in the Dark

The copulatory behavior pattern of house musk shrews paired for 24 h starting at either 09:00 (light) or 20:00 (dark) was investigated. Ejaculatory behaviors were observed in both light and dark periods, when mating was started at 09:00. However, the males ejaculated only in the dark period when they were paired at 20:00

Approximate Spin Projection for Broken-Symmetry Method and Its Application

A broken-(spin) symmetry (BS) method is now widely used for systems that involve (quasi) degenerated frontier orbitals because of their lower cost of computation. The BS method splits up-spin and down-spin electrons into two different special orbitals, so that a singlet spin state of the degenerate system is expressed as a singlet biradical. In the BS solution, therefore, the spin symmetry is no longer retained. Due to such spin-symmetry breaking, the BS method often suffers from a serious problem called a spin contamination error, so that one must eliminate the error by some kind of projection method. An approximate spin projection (AP) method, which is one of the spin projection procedures, can eliminate the error from the BS solutions by assuming the Heisenberg model and can recover the spin symmetry. In this chapter, we illustrate a theoretical background of the BS and AP methods, followed by some examples of their applications, especially for calculations of the exchange interaction and for the geometry optimizations

Optimum Design of Step Cascades for Uranium Enrichment by Gaseous Diffusion Process

When the optimization of a step cascade is carried out directly on the basis of an exact formula, the calculus of minimization of a multi-variable function is essential. The numerical calculation is very complex and a brief estimation becomes impossible as the number of steps increases, because the number of variables in the calculus amounts to (2ₘ₋1) in all for an m-steps cascade. In this paper an approximate formula of good feasibility and sufficient accuracy is proposed for the determination of the number of stages and interstage flow rate required for the plant of uranium enrichment by gaseous diffusion process. By using an approximate formula, the minimization of multi-variable function in the optimization of step cascades is able to be avoided. The applicability of the proposed method is verified by the calculation of a typical plant for uranium enrichment

Strain differences in pubertal development of male rats’ penile reflexes

The penile reflexes in outbrcd Wistar, SD and inbred Fischer strain male rats aged from 23 to 62 days were observed for 15 min following sheath retraction. Plasma Luteinizing hormone (LH) and testosterone levels were measured at 23, 37, 51and 70 days of age by RIA. All Wistar and SD rats displayed erection: cups and flips before plasma LH and testosterone levels peaked at 51 days of age, whereas in Fischer strain males, erections, flips, but not cups began to be seen around peak levels of these hormones at 51 days of age. The pubertal development of penile reflexes in Fischer strain males was slower than that in Wistar and SD Stocks. The present study is the first to clarify the strain differences in pubertal development of male rats‘ penile reflexes

Effects of rat- prolactin 0n ingestive behavior and leptin levels in adult male rats

Previous studies have indicated that ovine- or bovine-prolactin stimulates ingestive behavior in female, but not in male rats; i.e., that prolactin has sex-specific effects on ingestive behavior. The question addressed here was whether ingestivebehavior in male rats would be induced by rat-prolactin. In a preliminary test male rats were allowed to ingest a 1 M solution of sucrose from a drinking spout. After daily intake of sucrose became stabilized, the males received rat-prolactin by pituitary grafting. The results showed that pituitary grafling both stimulates ingestive behavior and increases serum leptin levels in male rats. These findings coupled with previous findings suggest that proinctin has species-specific effects on ingestivc behavior

Effectiveness of Winter-Flooding in Organic Rice Farming and Some Relating Management Practices

Poster Session

Age-Related Changes in the Penile Reflex of Rats

The penile reflex in sexually experienced male rats aged 10 and 44 weeks was observed for 20 min following sheath retraction. All 7 males aged 10 weeks showed erections, cups arid flips, while of 5 males aged 44 weeks only 2 showed erections.Frequencies of the above behaviors in aged males were significantly lower than that in young males. The decrease of penile reflexes with aging was similar to that of copulatory behavior with aging, when paired with receptive females. The presentstudy is the first to clearly establish the pattern of penile reflexes in aged rats