"A lot of it had to do with the decline of heavy industry, which employed a lot of blacks and blue-collar whites, in a whole set of Rust Belt states, " he said.

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The demolition of the Third Avenue Elevated subway line set off a building boom and a white-collar influx, most notably of young educated women who suddenly found themselves free of family, opprobrium, and, thanks to birth control, the problem of sexual consequence.

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Majora Carter, who set up Sustainable South Bronx to help lift the area out of poverty by creating green-collar jobs, is frustrated by this difference between the European and American industries.

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Within that constituency, interviewers were then told to find people with a given set of characteristics--ie, a certain proportion of men and women, of blue-collar and white-collar workers.

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