The Los Angeles Business Journal’s index of largest local public companies closed down slightly for the week ended Nov. 12 as investors reacted to both global economic worries and mixed local earnings reports.

The weighted LABJ index fell 0.59 percent to 115.35, with decliners outpacing gainers 103 to 79.

Among the winners was Los Angeles medical imaging center operator RadNet Inc., which jumped 17 percent to $2.65, even though its smaller third quarter loss didn’t meet analysts’ expectations.

CyberDefender Corp., a Los Angeles provider of Internet security software, reported a larger third-quarter net loss but still gained nearly 14 percent on a 188 percent jump in revenue.

El Segundo semiconductor maker International Rectifier Corp. continued to benefit from last week’s better-than-expected first-quarter profit report, adding 9.5 percent this week to close at $27.25

Among the biggest decliners was downtown office landlord MPG Office Trust Inc. The real estate investment trust dropped 13.6 percent after announcing that Chief Executive Nelson C. Rising had resigned in response to strategic differences with his board.

Stamps.com fell 12 percent to $13.29 as investors appeared to take profits from an earlier rise in share price prompted by strong third-quarter results from the Los Angeles online postage and shipping services provider.

Physicians Formula Holdings Inc. fell 11.7 percent to $$3.55 after the Azuza hypoallergenic makeup manufacturer reported a larger third-quarter loss.