The dynamical stability and evolution of disc galaxies with different disc thickness as well as various fraction and concentration of stellar counter-rotation is investigated with self-consistent numerical simulations. In particular, systems of nested, counter-rotating, stable bars are presented. As for the direct case, the nuclear secondary bar rotates faster than the primary bar. Contrary to ...

Recent studies, and a large body of anecdotal evidence, suggest that upgrades are unreliable and often end in failure, causing downtime and data-loss. While this is sometimes due to software defects in the new version, most upgradefailures are the result of faults in the upgrade procedure, such as broken dependencies. In this paper, we present data on upgrade failures from three independent sou...

The source parameters of the 1994 Bolivian earthquake (magnitude Mw = 8.3) suggest that the maximum seismic efficiency eta was 0.036 and the minimum frictional stress was 550 bars. Thus, the source process was dissipative, which is consistent with the observed slow rupture speed, only 20% of the local S-wave velocity. The amount of nonradiated energy produced during the Bolivian rupture was com...

The Rat Island earthquake of February 4, 1965 (origin time 05h 01m 21.8s, h = 40 km), is one of the largest earthquakes recorded in recent years. On the basis of the radiation patterns and the amplitudes of the great circle Rayleigh and Love waves, the earthquake is found to have the following characteristics: fault plane dip, 18ø; fault plane dip direction, N19øE; rupture propagation direction...

The source of repeating earthquakes on creeping faults is modeled as a weak asperity at a border between much larger locked and creeping patches on the fault plane. The x−1 2 / decrease in stress concentration with distance x from the boundary is shown to lead directly to the observed scaling T M ∝ 0 1 6 / between the average repeat time and average scalar moment for a repeating sequence. The s...