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CUPERTINO, Calif. — Nasdaq brought its market open festivities to Apple’s

sprawling Silicon Valley headquarters on Tuesday, the eve of the company’s 50th birthday.

From a desk inside Apple Park, the ring-shaped campus that Steve Jobs spent his last years helping design, Tim Cook rang the opening bell and, in the process, ushered in the iPhone maker’s second half-century.

It was a celebratory occasion, but one arriving at a pivotal point for an iconic American company that faces major challenges today and in the years ahead as the technology industry gets swept up by artificial intelligence.