BELGRADE, Serbia — Serbia toughened its stand on Kosovo Tuesday as parliament decided that a planned new constitution would refer to the disputed province as an "integral" part of Serbia, regardless of U.N.-led negotiations on whether to grant it independence. The parliamentary vote effectively ruled out Belgrade's consent if the international talks decide in favor of the majority ethnic Albanians who want the province to be independent. The talks began this year to try to resolve the future of Kosovo _ a province about the size of Connecticut that has been run by the United Nations since NATO launched a...