Small-cap stocks traded lower on Monday, breaking from two of the major indices to align with the sinking Nasdaq for most of the day before seeing an afternoon slump below even those levels. Contributing to this trend were Sigma Designs ( SIGM) and GTX ( GTXI), which were each hit with negative analyst research. Sigma, a maker of silicon-based media processors, lost 12.4% to $23.43 after American Technology Research cut its rating to sell, citing higher competition from likeminded Chinese companies. In the case of GTX, a Leerink Swann & Co. analyst said flaws in an advanced-phase study of the biotech's prostate-cancer treatment, Acapodene, might complicate proving the drug's effectiveness. The analyst lowered GTX's rating to market perform from outperform, pressuring shares down $2.96, or 13.2%, to $19.51. Elsewhere, CanArgo Energy ( CNR), an oil-and-gas company based in the Channel Islands, said its Georgian Manavi M12 test well didn't sustain flow and will need powerful pumping equipment that isn't currently available in Georgia. Shares closed 13% lower at 94 cents. Among other small-cap stocks on the downturn today, Sterling Financial ( SLFI) gave up 19.6% to $16.65 after saying it needs to restate results for 2004 through 2006; Accentia Biopharmaceuticals ( ABPI) sank 17.5% to $2.50; and ICO ( ICOC), which makes specialty resins and concentrates, fell 7% to $6.63. On the other hand, Oklahoma's North American Galvanizing & Coatings ( NGA), which sells services to the steel industry, catapulted 32.3% to $10.49 after first-quarter income more than doubled from last year to 28 cents a share. Ceragon Networks ( CRNT) also climbed on positive earnings. The Israel-based communications-equipment maker bested first-quarter expectations by a penny a share and raised full-year sales guidance, spurring shares higher by 16.4% to $6.94.