What is the fine-grained topic of the following text: Appointed in August 2010 as Music Director Designate, she led the Sinfonietta in a concert attended by over 7,000 people in Millennium Park in August of 2011 to introduce her to the people of Chicago, followed by four highly praised subscription season concerts. Only return the topic.
Music Director's debut and concerts with the Sinfonietta in Chicago.