The sudden appreciation of the yen in the wake of the Bank of Japan's surprise interest rate hike and hawkish stance is largely seen as the main reason the Nikkei stock index's recent plunge eclipsed those of global markets.With the yen apparently beginning to stabilize, the equities market will likely return to calm. But whether the Nikkei index rebounds toward the 40,000 level remains to be seen due to the unclear prospects of the U.S. economy, analysts say.The "BOJ shock" was behind the crash that led the benchmark to shed some 7,600 points during a three-day losing streak through Monday…READ FULL ARTICLE