Analyst upgrades: EMC, TSCDY, SLG, ARBA and MOT

MOST NOTEWORTHY: EMC Corporation, Tesco PLC, SL Green Realty, Ariba and Motorola were today's noteworthy upgrades:

EMC Corporation (NYSE: EMC) was upgraded to Outperform from Peer Perform at Bear Stearns on valuation. Shares were also upgraded to Buy from Hold at Citigroup after coming off restriction to reflect the long-term benefits of virtualization and valuation.
Tesco (OTC: TSCDY) was upgraded to Buy from Hold at Citigroup on valuation and the company's growth prospects.
SL Green Realty Corporation (NYSE: SLG) was upgraded to Buy from Hold at Keybanc based on valuation. The firm views concerns regarding NYC office demand as overblown.
Cowen expects FY07 to be a tough year for Ariba Inc (NASDAQ: ARBA) as benefits from the on-demand subscription model are realized. The firm upgraded shares to Outperform from Market Perform.
Motorola Inc (NYSE: MOT) was upgraded to Outperform from Sector Perform at RBC Capital citing firming trends in its handset division.

OTHER UPGRADES:

Jefferies upgraded Optium Corporation (NASDAQ: OPTM) to Buy from Hold.
JP Morgan upgraded Susster Holdings Corporation (NASDAQ: SUSS) to Overweight from Neutral.
Thomas Weisel upgraded Vishay Intertechnology (NYSE: VSH) to Overweight from Market Weight.
Royal Caribbean Cruises (NYSE: RCL) was upgraded to Strong Buy from Outperform at Raymond James.