Nikkei falls on Ukraine woes, but hopes of domestic buying limit losses

* Trust banks may be buying Topix - analysts * Nikkei off 1.0 pct for week, off 1.7 pct for month * Pioneer tumbles after dissolving alliance with Sharp By Ayai Tomisawa TOKYO, Aug 29 (Reuters) - Japan's Nikkei share average fell on Friday morning as tensions in the Ukraine conflict flared up again, but hopes that domestic investors would start buying up large-cap stocks limited the losses. The Nikkei dropped 0.5 percent to 15,376.16 in mid-morning trade. For the week, the N