The solar shakeout continues as Abound Solar, a Colorado startup that aimed to take on industry leader First Solar with a $400 million federal loan guarantee to build photovoltaic panel factories, halts production and lays off 180 workers. In addition to the $400 million loan guarantee, Abound, which was founded in 2007, has raised $260 million in venture funding from investors that include Invus Group, Bohemian Companies, DCM, GLG Partners, Technology Partners, BP Alternative Energy and West Hill Investors. Whether Abound can compete in an increasingly tough solar market remains in question.