COMPUTATIONAL FLUID DYNAMICS

has been adopted by many industries to provide a better understanding of countless applications. New and unusual uses for the technology continue to appear, as evidenced by our cover story on archaeological analysis (page 5). While the extent of an ancient municipal water system in Syria was unearthed by excavation, the cleverness of the hydraulic engineers at the time of construction wasn’t truly appreciated until engineers simulated the water flow through the pipes and connections of this historical resource. Other unique applications of CFD can also be found in this issue of Fluent News. For example, the buildup of dust particles on a filter is described on page 10; the cooling of cables to be used in a large-scale fusion reactor currently being planned ON THE SUPPLEMENT COVER: Heat flux through the nasal mucosal sections of a healthy nos

The Regai Dzive Shiri Project: a cluster randomised controlled trial to determine the effectiveness of a multi-component community-based HIV prevention intervention for rural youth in Zimbabwe--study design and baseline results.

OBJECTIVE: To assess the effectiveness of a community-based HIV prevention intervention for adolescents in terms of its impact on (1) HIV and Herpes simplex virus type 2 (HSV-2) incidence and on rates of unintended pregnancy and (2) reported sexual behaviour, knowledge and attitudes. METHODS: Cluster randomised trial of a multi-component HIV prevention intervention for adolescents based in rural Zimbabwe. Thirty communities were selected and randomised in 2003 to early or deferred intervention implementation. A baseline bio-behavioural survey was conducted among 6791 secondary school pupils (86% of eligibles) prior to intervention implementation. RESULTS: Baseline prevalences were 0.8% (95% CI: 0.6-1.0) for HIV and 0.2% (95% CI: 0.1-0.3%) for HSV-2. Four girls (0.12%) were pregnant. There was excellent balance between study arms. Orphans who made up 35% of the cohort were at increased risk of HIV [age-sex adjusted odds ratio 3.4 (95% CI: 1.7-6.5)]. 11.9% of young men and 2.9% of young women reported that they were sexually active (P < 0.001); however, there were inconsistencies in the sexual behaviour data. Girls were less likely to know about reproductive health issues than boys (P < 0.001) and were less likely to have used and to be able to access condoms (P < 0.001). CONCLUSION: This is one of the first rigorous evaluations of a community-based HIV prevention intervention for young people in southern Africa. The low rates of HIV suggest that the intervention was started before this population became sexually active. Inconsistency and under-reporting of sexual behaviour re-emphasise the importance of using externally validated measures of sexual risk reduction in behavioural intervention studies