Two papers in the Journal this week focus on the potential impact of cannabis use on mental health outcomes. Di Forti et al (pp. 488–491) examined the risk of psychosis associated with use of high-potency cannabis. They found that individuals presenting with a first episode of psychosis were no more likely than local population controls to have ever taken cannabis but the former were more likel...

We currently have a wealth of geographic information on the Web that is available in different forms ranging from images, maps, spatial databases, and tables to simple texts such as informal city guides, description of landscapes, and reports of bird watching activities. One of the most recent initiatives in trying to efficiently index, retrieve, and integrate information on the Web is the Sema...

the main challenge of a search engine is ranking web documents to provide the best response to a user`s query. despite the huge number of the extracted results for user`s query, only a small number of the first results are examined by users; therefore, the insertion of the related results in the first ranks is of great importance. in this paper, a ranking algorithm based on the reinforcement le...

in iranian language learning contexts, writing in english is an important challenge for learners, since it is usually treated as a secondary skill and is led to the periphery of language classes, due to its time-consuming nature. computer technology and namely the free online environments available in the world wide web (www) offer possibilities for moving beyond such confinements. asynchronous...