SATURDAY PASOK leader George Papandreou begins a two-day tour of Ptolemaida, Kastoria and Kozani prefectures. To tomorrow. – Communist Party youth organization holds a conference «Knowledge is Power,» at 7 p.m. at the the party’s conference center in Perissos. Party president Aleka Papariga will speak. – Deputy Foreign Minister Theodoros Kassimis visits Istanbul to represent the Greek government at the celebration of the Sunday of Christian Orthodoxy. To tomorrow. – Justice Minister Anastassis Papaligouras to address the general meeting of the Union of Senior Judicial Officials, at 10 a.m. at the Athens Bar Association. – Communist Party (KKE) hosts the preliminary meeting of the communist and labor parties in preparation of the ninth international convention in Athens later this year. – International roundtable discussion on «Hemorrhoids: A Disease of Civilization and a Plague on the Economy» is being held at the Grande Bretagne Hotel in Athens. To tomorrow. Tel. 210.363.7318. – The Association of Greek Architects (SADAS-PEA) holds a conference on «Policies for Architecture and the Urban Environment in Greece,» at 9.30 a.m. in the amphitheater at the Culture Ministry. Tel. 210.321.5146 or log on to – The Thessaloniki Organization for Women’s Employment & Resources (TOWER) holds a discussion on «Your Office at Home: A Recipe for Success,» at 10.30 a.m. at the campus of New York College in Thessaloniki. Tel. 2310.311.083 or log on to SUNDAY Defense Minister Evangelos Meimarakis visits Litohoro to attend anniversary celebrations for the uprising of the Olympos area in 1878 against Ottoman rule. – Deputy Foreign Minister Evripidis Stylianidis to meet with the deputy executive director of the World Food Program, John M. Powell. – Deputy Culture Minister Giorgos Orfanos visits Komotini prefecture. – Synaspismos Left Coalition holds a conference on «Europe in Crisis: Greece a Laggard – The Alternative Proposal of Synaspismos,» at 10.30 a.m. at the Olympion cinema in Thessaloniki. Synaspismos Euro MP Dimitris Papadimoulis to speak.