ROUNDUP L.F. Rothsc To Restructure, Cut Work Force  
n L.F. Rothschild Holdings Inc., hurt by internal strife, heavy losses and growing competition in the aftermath of the stock market plunge, announced a severe restructuring plan yesterday to narrow its business and cut staff by 40 percent.</br></br>Rothschild became the third big Wall Street firm in the five days to announce impending deep cutbacks in operations and staff. E.F. Hutton Group Inc. and Kidder, Peabody & Co. announced restructuring steps last week that could result in losses of up to 7,000 jobs.</br></br>Andrew L. Berger, president of Rothschild's broker-dealer subsidiary, L.F. Rothschild & Co., said th& firm would achieve some of the layoffs by phasing out the clearing activities of its retail accounts, meaning that Rothschild would no longer handle the financial settlements of clients' securities transactions.</br></br>o Interest rates on short-term Treasury securities rose sharply in yesterday's auction with six-month bills hitting the highest level since mid-October.</br></br>The Treasury sold $6.4 billion in three-month bills at an average discount rate of 5.81 percent, up from 5.49 percent last week. Another $6.4 billion was sold in six-month bills at an average discount rate of 6.42 percent, up from 6.12 percent last week.