inputs: hypothesis: Castro took power in Cuba in 1959. premise: It contained "a great number of inadmissible concepts", he wrote, and did not acknowledge the calls for better Cuba-US ties. "Who is now demanding our exclusion? Perhaps they don't understand that times of exclusionary agreements against our people have been left far behind," he wrote. US President Barack Obama has taken a less confrontational approach to the communist nation than his predecessor, George W Bush, our correspondent adds. But his administration continues to insist that there must be progress towards democracy and on human rights before the trade embargo can be lifted. The US began imposing restrictions on Cuba after Mr Castro took power in 1959, making it the only Communist state in the Americas - and a Cold War flashpoint.