Preovulatory oocytes were collected from ovaries of beagle bitches that had received superovulatory treatment. They were cultured in a modified Krebs-Ringer bicarbonate solution containing 10% fetal calf serum and 30 mg/L gentamicin sulfate for up to 72 h. About 32% of oocytes reached metaphase II by 72 h of culture. When these in vitro-matured oocytes were inseminated with ejaculated beagle spermatozoa that had been preincubated for 4 h, sperm penetration of the zona pellucida started about 1 h after insemination, and both male and female pronuclei were seen in the ooplasm at 8 h after insemination. At 18-20 h after insemination, oocytes were transferred to Whitten's medium and cultured for 76-78 h. The first cleavage was observed at 48 h after insemination, and 15 of 45 oocytes developed to the 2-8-cell stage. These results demonstrate that in vitro-matured canine oocytes can be fertilized and develop to the 8-cell stage in vitro.

Magnetization dynamics induced by parametric excitation in a magnetic dot has been investigated by using ac spin pumping and inverse spin-Hall effects. An Ising-like pair of states with different precession phases was found to be stabilized in a controllable way under the excitation. The result shows that the dot can be used as a parametron-bit carrier. Upon increasing the excitation power, stochastic transition between the states was observed, and the occurrence probability of each state can be tuned by means of additional microwaves, opening an application to probabilistic bit operation.

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