in this article, multiple-product pvrp with pickup and delivery that is used widely in goods distribution or other service companies, especially by railways, was introduced. a mathematical formulation was provided for this problem. each product had a set of vehicles which could carry the product and pickup and delivery could simultaneously occur. to solve the problem, two meta-heuristic methods...

BACKGROUND Antiretroviral treatment programs in sub-Saharan Africa have high rates of early mortality and loss to follow-up. Switching to second-line regimens is often delayed because of limited access to laboratory monitoring. METHODS Retrospective analysis was performed of a cohort of adults who initiated a standard first-line antiretroviral treatment at 5 public sector sites in 3 African c...

Many species of pickup ions, both of interstellar origin and from an inner, distributed source have been discovered using data from the Solar Wind Ion Composition Spectrometer (SWICS) on Ulysses. Velocity distribution functions of these ions were measured for the first time over heliocentric distances between 1.35 and 5.4 AU, both at high and low latitudes, and in the disturbed slow solar wind ...