An 'urban heat island' effect, fed by the city's growth, is trapping heat and making temperatures soar. ___ Arizona is poised to take another record. No. 1 in the nation for most illegal immigrants crossing the border, or No. 1 in the nation for identity thefts. This "one" directly corresponds with another No. 1 – its status as the fastest-growing state in the nation. While news of global warming becomes as common as the wheeze of air conditioners here, Phoenix is fighting a different, if related, problem. In part because of heavy growth – particularly in the Phoenix metro area...