Tokyo -- Standard&Poor's CreditWire 7/28/98 -- Standard&Poor's today lowered its long-term rating of Toshiba Corp. and related entities to single-'A'-minus from single-'A', and lowered its short-term rating to 'A-2' from 'A-1'. At the same time, the ratings were removed from CreditWatch where they were placed on May 19, 1998. The outlook on the long-term ratings is negative. The downgrade reflects Toshiba's weakened positions in its major business lines, resulting in higher earnings volatility and worsened prospects for recovery in the near term. In Toshiba's core information/communication systems segment, which generates about 40% of consolidated sales, the volatile personal computer market continues to impact performance. Meanwhile, profitability in the heavy electrical apparatus segment is likely to remain