Further optical observations of HZ Herculis

HST / GHRS observations of AM Herculis ⋆

We present phase-resolved spectroscopy of AM Herculis obtained with the HST/GHRS when the system was in a high state. The ultraviolet light curve shows a quasi-sinusoidal modulation, which can be explained by a hot spot on the rotating white dwarf. The broad Lyα absorption expected for photospheric radiation of a moderately hot white dwarf is largely filled in with emission. The UV/FUV spectrum...

BeppoSAX observations of AM Herculis in intermediate and high states

Temporal and spectral analyses from BeppoSAX observations of AM Her performed during both an intermediate and a high state are presented and discussed. Optical observations taken a few days after the X–ray ones are also presented. During the intermediate state observation, the source was in its “normal”, one–pole accretion mode. In the high state it switched to an hitherto unobserved atypical ”...

Further Observations

Initiation and termination of tachycardia was studied by electrical stimulation of the heart in 14 patients with ventricular tachycardia (VT) not related to acute myocardial infarction (group A) and in six patients in whom the tachycardia occurred within 24 hours after the onset of acute myocardial infarction (group B). Results favor re-entry as the mechanism of tachycardia in group A patients....

Vertex Cover: Further Observations and Further Improvements

Recently, there has been increasing interest and progress in lowering the worstcase time complexity for well-known NP-hard problems, particularly for the Vertex Cover problem. In this paper, new properties for the Vertex Cover problem are indicated, and several simple and new techniques are introduced, which lead to an improved algorithm of time O kn + 1 2852 for the problem. Our algorithm also...

Further Observations on Plague