2 research outputs found
Effects of initial-state dynamics on collective flow within a coupled transport and viscous hydrodynamic approach
We evaluate the effects of preequilibrium dynamics on observables in
ultrarelativistic heavy-ion collisions. We simulate the initial nonequilibrium
phase within A MultiPhase Transport (AMPT) model, while the subsequent
near-equilibrium evolution is modeled using (2+1)-dimensional relativistic
viscous hydrodynamics. We match the two stages of evolution carefully by
calculating the full energy-momentum tensor from AMPT and using it as input for
the hydrodynamic evolution. We find that when the preequilibrium evolution is
taken into account, final-state observables are insensitive to the switching
time from AMPT to hydrodynamics. Unlike some earlier treatments of
preequilibrium dynamics, we do not find the initial shear viscous tensor to be
large. With a shear viscosity to entropy density ratio of , our model
describes quantitatively a large set of experimental data on Pb+Pb collisions
at the Large Hadron Collider(LHC) over a wide range of centrality: differential
anisotropic flow , event-plane correlations, correlation
between and , and cumulant ratio .Comment: 10 pages, v2: minor revisio
Mother-to-Infant Microbial Transmission from Different Body Sites Shapes the Developing Infant Gut Microbiome
The acquisition and development of the infant microbiome are key to establishing a healthy host-microbiome symbiosis. The maternal microbial reservoir is thought to play a crucial role in this process. However, the source and transmission routes of the infant pioneering microbes are poorly understood. To address this, we longitudinally sampled the microbiome of 25 mother-infant pairs across multiple body sites from birth up to 4 months postpartum. Strain-level metagenomic profiling showed a rapid influx of microbes at birth followed by strong selection during the first few days of life. Maternal skin and vaginal strains colonize only transiently, and the infant continues to acquire microbes from distinct maternal sources after birth. Maternal gut strains proved more persistent in the infant gut and ecologically better adapted than those acquired from other sources. Together, these data describe the mother-to-infant microbiome transmission routes that are integral in the development of the infant microbiome