Despite my best intentions, I only lasted for about 90 minutes at Peabody's Opera Etudes program Tuesday night -- enough to hear four of the seven new one-act operas composed by Peabody grad students and united around a theme of "Women's Studies." It had been a long day for me, and I confess that, as the immortal Mame Dennis would have said, "Auntie needed fuel." So, sincere apologies to the creators whose work I didn't get to sample.