US STOCKS-Wall St turns lower as earnings concerns linger
* JPMorgan rises after results, Wells Fargo lower
* Norfolk Southern gives weak outlook, shares fall
* Nokia in talks to buy Alcatel-Lucent
* Dow up 0.2 pct, S&P flat, Nasdaq down 0.3 pct (Updates to midday trading)
By Ryan Vlastelica
NEW YORK, April 14 (Reuters) - U.S. stocks were flat on Tuesday as investors digested the initial major earnings of the first-quarter reporting season, which showed some weakness though companies topped lowered expectations.
Norfolk Southern Corp was the biggest decliner on the S&P 500, dropping 5.6 percent to $98.95 a day after it forecast a surprise drop in its first-quarter earnings and revenue.
Johnson & Johnson also cut its full-year forecast, citing the impact of a strong dollar, though adjusted earnings topped expectations. Shares of the Dow component were flat after earlier rising nearly 1 percent.
The weak outlooks offset a positive report from JPMorgan Chase & Co, which posted stronger-than-expected earnings growth, helped by a rebound in fixed-income trading. The stock rose 1.3 percent to $62.86. Continuación...