Cosmological Simulation for Fuzzy Dark Matter Model

Fuzzy Dark Matter (FDM), motivated by string theory, has recently become a hot candidate for dark matter. The rest mass of FDM is believed to be $\sim 10^{-22}$eV and the corresponding de-Broglie wave length is $\sim 1$kpc. Therefore, the quantum effect of FDM plays an important role in structure formation. In order to study the cosmological structure formation in FDM model, several simulation techniques have been introduced. We review the current status and challenges in the cosmological simulation for the FDM model in this paper.Comment: 10 pages, 2 tables, published on Front. Astron. Space Sci. under the topic: Dark Matter - Where is it? What is it

Effects of Maternal Undernutrition on Glomerular Ultrastructure in Rat Offspring

BackgroundIntrauterine growth restriction (IUGR) can reduce glomerular number and increase blood pressure in rats. The aim of this study was to assess the effects of maternal undernutrition during late gestation on glomerular ultrastructure in adult rat offspring.MethodsTimed pregnant Sprague-Dawley rats were used. Control dams received regular food throughout pregnancy, while experimental dams received 50% of control food intake from days 15-21 of gestation. Glomerular ultrastructure was quantified in male offspring at 16 weeks of age.ResultsThe ultrastructure of the filtration apparatus in the IUGR rat glomeruli was indistinguishable from that in the control rat glomeruli. The relative volumes of the glomerulus occupied by podocytes, capillaries, and mesangium, and the thickness of the glomerular basement membrane (GBM), and width of the filtration slit were comparable between control and IUGR rats.ConclusionThese results indicate that glomerular ultrastructure is not affected by maternal undernutrition and suggest that altered glomerular ultrastructure is not a contributory factor to the pathogenesis of hypertension following maternal undernutrition

Hydrodynamics of Ultra-Relativistic Heavy-Ion Collisions

Relativistic hydrodynamic calculations are presented to describe the dynamics of ultra-relativistic heavy-ion collisions. In contrast to the "standard picture" of the field, our calculations do not assume scaling symmetry, and in fact we find large scaling violations near the fragmentation regions. In our 1+1-dimensional calculations, we find that while the hydrodynamic evolution is very sensitive to the formation and thermalization time and to the models of the source terms, the effects of changing the viscosity and the equation of state are small. Our 2+1-dimensional calculations show that transverse expansion is not important in the central rapidity region. We also present a brief review of the proposed signatures of the formation of quark-gluon plasma in high energy heavy-ion collisions, as examples of applications of hydrodynamics.</p

R-process nucleosynthesis during explosion of low-mass neutron stars in close binaries

We investigate the explosion of low-mass neutron stars through Newtonian hydrodynamic simulations. We couple the hydrodynamics to a nuclear reaction network consisting of $\sim 4500$ isotopes to study the impact of nuclear reactions, mainly neutron capture, $\beta$-decays, and spontaneous fission of nuclei, on the development of hydrodynamic instability of a neutron star. We show that after mass removal from the surfaces, low-mass neutron stars undergo delayed explosion, and an electron anti-neutrino burst with a peak luminosity of $\sim3\times10^{50}$ erg s$^{-1}$ is emitted, while the ejecta is heated to $\sim10^{9}$ K. A robust r-process nucleosynthesis is realized in the ejecta. Lanthanides and heavy elements near the second and third r-process peaks are synthesized as end products of nucleosynthesis, suggesting that the explosions of low-mass neutron stars could be a potentially important source of solar chemical elements.Comment: 12 pages, 13 figure