31,427 research outputs found
Managerial entrenchment and firm value: a dynamic perspective
We examine the impact of managerial entrenchment on firm value using a dynamic model with firm fixed effects. To estimate the model, we employ the long-difference technique, which is shown by our simulation to deliver the least biased estimates. Based on a large sample of U.S. companies, we document a significantly negative and causal effect of managerial entrenchment on firm value after taking into account omitted variables, reverse causality, and highly persistent endogenous variables. Additional analysis suggests that the causality running from managerial entrenchment to firm value is more pronounced than that for reverse causality.Chang acknowledges financial support from Academic Research Fund Tier 1 provided by Ministry of Education (Singapore). Zhang acknowledges the financial supports for his PhD research from the University of Melbourne
Statefinder Parameters for Five-Dimensional Cosmology
We study the statefinder parameter in the five-dimensional big bounce model,
and apply it to differentiate the attractor solutions of quintessence and
phantom field. It is found that the evolving trajectories of these two
attractor solutions in the statefinder parameters plane are quite different,
and that are different from the statefinder trajectories of other dark energy
models.Comment: 8 pages, 12 figures. accepted by MPL
Mediating exchange bias by Verwey transition in CoO/Fe3O4 thin film
We report the tunability of the exchange bias effect by the first-order
metal-insulator transition (known as the Verwey transition) of Fe3O4 in CoO (5
nm)/Fe3O4 (40 nm)/MgO (001) thin film. In the vicinity of the Verwey
transition, the exchange bias field is substantially enhanced because of a
sharp increase in magnetocrystalline anisotropy constant from high-temperature
cubic to lowtemperature monoclinic structure. Moreover, with respect to the
Fe3O4 (40 nm)/MgO (001) thin film, the coercivity field of the CoO (5 nm)/Fe3O4
(40 nm)/MgO (001) bilayer is greatly increased for all the temperature range,
which would be due to the coupling between Co spins and Fe spins across the
interface
Electron Delocalization in Gate-Tunable Gapless Silicene
The application of a perpendicular electric field can drive silicene into a
gapless state, characterized by two nearly fully spin-polarized Dirac cones
owing to both relatively large spin-orbital interactions and inversion symmetry
breaking. Here we argue that since inter-valley scattering from non-magnetic
impurities is highly suppressed by time reversal symmetry, the physics should
be effectively single-Dirac-cone like. Through numerical calculations, we
demonstrate that there is no significant backscattering from a single impurity
that is non-magnetic and unit-cell uniform, indicating a stable delocalized
state. This conjecture is then further confirmed from a scaling of conductance
for disordered systems using the same type of impurities.Comment: 6 pages, 3 figures, published versio
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