my name is marcus yam. this is my "brief, but spectacular" take, on uncovering the unknown. >> woodruff: you can find additional "brief but spectacular" episodes on our website at www.pbs.org/newshour/brief. and that is the newshour for tonight. i'm judy woodruff. join us online, and again here tomorrow evening, when mark nashields and david brooksze the first democratic debates. for all of us at the pbs wshour, thank you, and we'll see you soon. >> major funding for the pbs newshour has been provided by: >> babbel. a language app that teaches real-life conversations in a new language, like spanish, french, ge >> consumer cellular.. >> financial services firm raymond james. >> and with the ongoing support of these institutions >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. captioning sponsored by newshour productions, llc captioned by media acce group at wgbh access.wgbh.org martha: hi. i'm martha stewa