Metal Poor Accretion in the Early Universe

In the early Universe, the chemical composition of matter was different from the one today, as then the heavier elements present today were still missing. The structure, evolution and stability of accretion discs in AGNs depends on the chemical composition of the material. I will present first results of model calculations of such primordial accretion discs.For the calculations, I use a generalized viscosity prescription and newly computed opacities in the range 40-40000 K. I will discuss the influence of the primordial chemical composition on the structure and stability of AGN accretion disks and compare them to the present day Universe situation.

反式肩关节置换术在肩关节置换翻修中应用的随访结果

在过去的10多年里肩关节置换的数量有所增加，其中采用反式全肩关节置换术的数量也在增加。然而，初次肩关节置换后进行翻修受无法修复的肩袖缺损、肱骨结节畸形愈合、骨不连和骨吸收等因素影响。因此，转为采用反向肩关节置换成为唯一的恰当选择。