... Summary. ... Subject of my Ph.D. thesis is the analysis and interpretation of the overall gas dynamics in the starburst galaxy NGC 1808, in comparison with other spiral galaxies in a similar evolutionary stage. ... c) nuclear outflow of neutral gas into the halo of the galaxy, . ... We have mapped the 21-cm absorption in the nuclear region of the starburst galaxy NGC 1808 using the VLA AnB-hybrid array with a resolution of approx. 5.2 arcsec (which corresponds to 275 pc). ...

metrologia The leap second: its history and possible future R. A. Nelson, D. D. McCarthy , S. Malys, J. Levine, B. Guinot, H. F. Fliegel , R. L. Beard and T. R. Bartholome w Abstract. This paper reviews the theoretica l motivatio n for the leap second in the context of the historica l evolutio n of time measurement . Th e periodic insertio n of a leap second step into th e scale of Coordinate d Universal Time (UTC) necessitates frequent changes in comple x timekeepin g systems an d is currentl y th e