Atomic, molecular, and Optical physics in the early universe: From recombination to reionization

Our knowledge of the evolution of the early Universe hinges, in part, on our understanding of the underlying atomic, molecular, and optical (AMO) processes occurring during that epoch. Here we review the relevant AMO physics from when it first became important at a redshift of z~. 6000, some 18,000. years after the Big Bang when electrons and ions began to recombine. The review continues through the formation of the first stars and galaxies and concludes after the radiation from these first objects has reionized the Universe at a z~. 10, about a billion years after the Big Bang. © 2014 Elsevier Inc

A highly virulent variant of HIV-1 circulating in the Netherlands

We discovered a highly virulent variant of subtype-B HIV-1 in the Netherlands. One hundred nine individuals with this variant had a 0.54 to 0.74 log10 increase (i.e., a ~3.5-fold to 5.5-fold increase) in viral load compared with, and exhibited CD4 cell decline twice as fast as, 6604 individuals with other subtype-B strains. Without treatment, advanced HIV-CD4 cell counts below 350 cells per cubic millimeter, with long-term clinical consequences-is expected to be reached, on average, 9 months after diagnosis for individuals in their thirties with this variant. Age, sex, suspected mode of transmission, and place of birth for the aforementioned 109 individuals were typical for HIV-positive people in the Netherlands, which suggests that the increased virulence is attributable to the viral strain. Genetic sequence analysis suggests that this variant arose in the 1990s from de novo mutation, not recombination, with increased transmissibility and an unfamiliar molecular mechanism of virulence