While many quick-service brands, like McDonald's, are thriving in this rough environment, fast-casual brands are still taking quite a hit. Speaking recently at an investor conference, Bert Vivian, co-CEO of P.F. Chang's told attendees to expect a trying first half of the year."I think it's going to be a cold first quarter in retail and in restaurants," the Associated Press quoted Vivian, who became co-CEO earlier this month after serving as president since 2000. At least he is more upbeat about the future. "Our intent is to be a survivor," he said. "We will come out of this year a stronger company."Though the chain's Q3 comps (their latest data) fell 3.1%, we would imagine that Q4 results probably will look a little worse. However, in the case of P.F. Chang's, we know more than a few people who are serious fans of the concept and would think there's still a demand for their offerings.Is it just a matter of pushing through the storm or will this sector of restaurants have trouble surviving?