Quantitative decision making for investment in global health intervention trials: case study of the NEWBORN study on emollient therapy in preterm infants in Kenya by Stylianou, A, Blanks, KJH, Gibson, RA, Kendall, LK, English, M, Williams, S, Mehta, R, Clarke, A, Kanyuuru, L, Aluvaala, J, Darmstadt, GL