GENEVA (AFP) - Talks in Geneva between the United States and North Korea aimed at reviving long-stalled nuclear negotiations have been very positive, Washingtons outgoing lead envoy Stephen Bosworth said Tuesday. We had some very positive and generally constructive talks with the DPRK delegation. We narrowed differences on several points and explored differences on other points, he told reporters after the two days of talks. Bosworth said however that the parties would need more time and discussion to reach an agreement and that the delegations would stay in touch through North Koreas mission in New York.