NEW YORK (TheStreet) -- CHANGE IN RATINGSAmerican Physicians Services ( AMPH) downgraded at Raymond James to Underperform from Outperform following announced $32.50/share takeover by ProAssurance. Camelot Information Systems ( CIS) initiated at Goldman with a Neutral rating. Clearwire ( CLWR) initiated at Kaufman Brothers with a Buy rating and $8.50 target. Company's wireless data services are set to increase significantly in 2011. Education Realty Trust ( EDR) initiated at Hillard Lyons with a Neutral rating. Student housing sector attractive for several reasons, but EDR is fairly valued. EZchip Semiconductor ( EZCH) initiated at Barclays with an Overweight rating and $30 price target. Fast growing market, complex products with long design cycles. FormFactor ( FORM) upgraded at Goldman to Neutral from Sell. Hewlett-Packard ( HPQ) upgraded at JMP Securities to Outperform from Market Perform. Mellanox Technologies ( MLNX) initiated at Barclays with an Equal Weight rating and $20 price target. 2Q disappointment will continue to weight on the stock at least until next results announcement. Nice Systems ( NICE) initiated at Barclays with an Overweight rating and $37 price target. Nice is benefiting from increasing regulatory requirements, continued spending on security surveillance, and potential to make aggressive acquisitions. PPL Corp ( PPL) downgraded at Citi to Hold from Buy. Catalysts in rearview mirror and falling commodity prices. Price target cut to $28.50 from $30.50. QLT Inc ( QLTI) initiated at CK Cooper with a Buy rating and $12 price target. QLTI will continue to be a player in the growing ophthalmology market. Rio Tinto ( RTP) upgraded at RBC Capital to Outperform from Sector Perform. Vantage Drilling ( VTG) coverage initiated at Jefferies with a Buy rating.