Ahead of a new earnings season that Wall Street analysts expect to show weak corporate growth US equities fell in mid-Tuesday trading.   Overall Wall Street sees a 2.8% year-to-year growth in quarterly earnings according to Thomson Reuters data but the figure represents a sharp downward revision from October estimates.   The Nasdaq Composite (INDEXNASDAQ:.IXIC) was down 0.48% to 3 084.04 points on trading volume of 805.98 million as of 12:21 p.m. EST.   Perion Network (NASDAQ:PERI) shot up 28.25% to $12.12. The Israeli maker of email and social-networking products provided a robust 2013 forecast saying that it expects sales for ...