Exit, Voice, and the Role of Corporate Directors: Evidence from Acquisition Performance

This study examines the characteristics of corporate boards for 82 companies that attempted 106 acquisitions during the 1980s. We find that poor performance is more likely to occur in firms that have recently experienced higher turnover of outside and lower turnover of inside directors. Companies with smaller boards, more reputable members, and larger equity holdings also outperform their counterparts. Our results do not suggest that more outside directors lead to improved performance but that outsiders often resign from the board instead of challenging managerial shirking. We conclude that choosing directors for whom board exit is costly will better reduce agency costs.

A Search for Resonant Structures in the Zodiacal Cloud with COBE DIRBE: The Mars Wake and Jupiter's Trojan Clouds

We searched the COBE DIRBE Sky and Zodi Atlas for a wake of dust trailing Mars and for Trojan dust near Jupiter's L5 Lagrange point. We compare the DIRBE images to a model Mars wake based on the empirical model of the Earth's wake as seen by the DIRBE and place a 3-sigma upper limit on the fractional overdensity of particles in the Mars wake of 18% of the fractional overdensity trailing the Earth. We place a 3-sigma upper limit on the effective emitting area of large (10-100 micron diameter) particles trapped at Jupiter's L5 Lagrange point of 6 x 10^17 cm^2, assuming that these large dust grains are distributed in space like the Trojan asteroids. We would have detected the Mars wake if the surface area of dust in the wake scaled simply as the mass of the planet times the Poynting-Robertson time scale.Comment: Sixteen pages, and figures 1, 2, 3a, 3b, 4, 5, 6, and 7. Accepted for publication in Icaru

Shockwaves in converging geometries

Plate impact experiments are a powerful tool in equation of state (EOS) development, but are inherently limited by the range of impact velocities accessible to the gun. In an effort to dramatically increase the range of pressures which can be studied with available impact velocities, a new experimental technique is being developed. The possibility of using a confined converging target to focus Shockwaves and produce a large amplitude pressure pulse is examined. When the planar shock resulting from impact enters the converging target the impedance mismatch at the boundary of the confinement produces reflected Mach waves and the subsequent wave interactions produce a diffraction cycle resulting in increases in the shock strength with each cycle. Since this configuration is limited to relatively low impedance targets, a second technique is proposed in which the target is two concentric cylinders designed such that the inner cylinder will have a lower shock velocity than the much larger shock velocity in the outer cylinder. The resulting dispersion in the wave front creates converging shocks, which will interact and eventually result in a steady Mach configuration with an increase in pressure in the Mach disk. Numerical simulations indicate a significant increase in pressure for both methods and show promise for the proposed concepts

Developing CBM in the Powder River Basin

5 pages (includes some color illustrations and maps)

Developing CBM in the Powder River Basin

5 pages (includes some color illustrations and maps)

Stochastic oscillations of adaptive networks: application to epidemic modelling

Adaptive-network models are typically studied using deterministic differential equations which approximately describe their dynamics. In simulations, however, the discrete nature of the network gives rise to intrinsic noise which can radically alter the system's behaviour. In this article we develop a method to predict the effects of stochasticity in adaptive networks by making use of a pair-based proxy model. The technique is developed in the context of an epidemiological model of a disease spreading over an adaptive network of infectious contact. Our analysis reveals that in this model the structure of the network exhibits stochastic oscillations in response to fluctuations in the disease dynamic.Comment: 11 pages, 4 figure

Medical Technology Transfer

The Biomedical Applications Team program sponsored by the National Aeronautics and Space Administration is an effective means for transferring aerospace technology to applications in medicine. A conceptual framework for medical technology transfer is presented to describe the transfer process in medicine and to supply a rationale for the Biomedical Applications Team methodology. Examples illustrate medical technology transfer at the material, design, and capacity levels. The roles of donor, recipient, and transfer agent are illustrated and factors essential to the success of medical technology transfer are summarized