From dawn to dusk, American composer Jeffrey Mumford’s evocative music takes its cues from the daily ebbing and flowing of natural light around and upon us. Tonight’s world premiere of Within diffuse echoes … softly spreading, a BBC commission, is conducted by Joana Carneiro, who is joined by soloist Denis Kozhukhin for Mendelssohn’s dashing, dazzling First Piano Concerto. Gustav Mahler’s typically majestic Fifth Symphony progresses from tragedy to triumph in five sweeping movements, including perhaps the most treasured music he ever wrote: the Adagietto, a love note to his wife.