Even more alarming for Europe is that questions have been raised about the future of the euro altogether.
Other analysts said recent developments had raised their hopes about the future.
The results, the researchers write in the journal Nature, raise questions about the future and the past.
Yet at the same time several factors are raising questions about the long-term future of these settlements.
The resulting ambiguity has raised serious questions about the future of software patents.
If true, they raise troubling questions about the future of the company.
The District's latest fiscal problems have raised new questions about the future of home rule.
But none raised doubts about the future of the shuttle program or America's commitment to sending men and women into space.
Her comments raised questions about the future on the jury of that white woman, someone whom the defense would clearly like to remove.
And along the way, he is raising some thorny questions about the future of online journalism.