PORTLAND, Maine (AP) – At least six organizations intend to apply for the last four available charter school slots in Maine. The six proposals, including a virtual school that has applied the last three years, sent letters of intent to the Maine Charter School Commission by Wednesday’s deadline. Maine charter schools are publicly funded but operate independently of public school districts. By law, the state has a cap of 10 charter schools until 2021. Five charter schools are currently in operation. A sixth charter school, Maine Connections Academy, plans to open in the fall and will be the state’s first virtual charter school, with students learning largely from home and getting lessons online. Some of the applicants want to open schools in the Lewiston-Auburn area; York County; Kennebunk and Sidney.