Principles of predicting plant virus disease epidemics.

Predicting epidemics of plant virus disease constitutes a challenging undertaking due to the complexity of the three-cornered pathosystems (virus, vector, and host) involved and their interactions with the environment. A complicated nomenclature is used to describe virus epidemiological models. This review explains how the nomenclature evolved and provides a historical account of the development of such models. The process and steps involved in devising models that incorporate weather variables and data retrieval and are able to forecast plant virus epidemics effectively are explained. Their application to provide user-friendly, Internet-based decision support systems (DSSs) that determine when and where control measures are needed is described. Finally, case studies are provided of eight pathosystems representing different scenarios in which modeling approaches have been used with varying degrees of effectiveness to forecast virus epidemics in parts of the world with temperate, Mediterranean, subtropical, and tropical climates.

Oral iron therapy for anaemia after orthopaedic surgery: randomized clinical trial.

BACKGROUND: Oral iron therapy is often used after orthopaedic surgery to improve haemoglobin levels. The aim of the present trial was to determine if administration of oral iron after orthopaedic surgery results in a better improvement of haemoglobin levels than a control treatment. METHODS: This was a double blind randomized controlled trial at a tertiary referral orthopaedic centre. The participants were patients undergoing elective hip or knee replacement surgery with normal iron and folic acid stores and no history of iron deficiency, and the primary outcome was the haemoglobin level 10 weeks after surgery. RESULTS: At 10 weeks the mean +/- SD haemoglobin in the iron group was 132.8 +/- 13.4 g/L and in the control group it was 128.0 +/- 10.6 g/L, a difference of 4.8 g/L with a 95% confidence interval for the difference of -1.2 to 10.7 g/l, P = 0.12. CONCLUSIONS: Iron taken after elective hip or knee replacement surgery does not result in higher haemoglobin 10 weeks after surgery, or a faster rate of increase in haemoglobin than a control treatment.