Three weeks after undergoing cancer surgery, Venezuelan President Hugo Chavez remains in delicate condition and has seen only slight improvement in his health, the countrys vice president said Tuesday. All the time we are hoping for his positive evolution, Vice President Nicolas Maduro said in an interview broadcast Tuesday night on Venezuelan state media. Sometimes, he has had slight improvements. Sometimes, he has remained stable. In the past four days, Maduro said, he had visited and spoken with Chavez twice and noted the Venezuelan presidents great strength as he fights to recover.