14,146 research outputs found
Electron capture across a nuclear resonance in the strong potential Born approximation
Abstract. The strong potential Born theory for charge transfer in fast, asymmetric ion-atom collisions has been extended to allow for nuclear resonant scattering using distorted nuclear waves. In the absence of a nuclear resonance, the semiclassical result is recovered. A large variation in the capture probability is found when the projectile energy passes through the resonance. As examples, we present results for the capture from the target K shell in the collisions of protons with 22Ne and 28Si, as well as for capture from the K and L shells of 58Ni in collisions with protons, and of I6O, "Ne and 28Si by He2+ impact. 1
Gender Bias in Nobel Prizes
Strikingly few Nobel laureates within medicine, natural and social sciences
are women. Although it is obvious that there are fewer women researchers within
these fields, does this gender ratio still fully account for the low number of
female Nobel laureates? We examine whether women are awarded the Nobel Prizes
less often than the gender ratio suggests. Based on historical data across four
scientific fields and a Bayesian hierarchical model, we quantify any possible
bias. The model reveals, with exceedingly large confidence, that indeed women
are strongly under-represented among Nobel laureates across all disciplines
examined
On the semiclassical impulse approximation for electron capture in asymmetric ion-atom collisions
Charge transfer at large scattering angles in the strong potential Born approximation
Abstract. We have calculated the Is-Is charge transfer probability for large projectile scattering angles in asymmetric ion-atom collisions, using the strong-potential Born approximation and including the effect of recoil on the projectile states non-perturbatively. A significant angular dependence is found. Numerical results for Is-Is capture in 0.3-20 MeV proton impact on C and Ne are presented, showing good agreement with recent experimental results. 1
Magnetization switching in nanoscale ferromagnetic grains: simulations with heterogeneous nucleation
We present results obtained with various types of heterogeneous nucleation in
a kinetic Ising model of magnetization switching in single-domain ferromagnetic
nanoparticles. We investigate the effect of the presence of the system boundary
and make comparison with simulations on periodic lattices. We also study
systems with bulk disorder and compare how two different types of disorder
influence the switching behavior.Comment: 3 pages, 4 Postscript figure
The Fractional Ornstein-Uhlenbeck Process: Term Structure Theory and Application
The paper revisits dynamic term structure models (DTSMs) and proposes a new way in dealing with the limitation of the classical affine models. In particular, this paper expands the flexibility of the DTSMs by applying a fractional Brownian motion as the governing force of the state variable instead of the standard Brownian motion. This is a new direction in pricing non defaultable bonds with offspring in the arbitrage free pricing of weather derivatives based on fractional Brownian motions. By applying fractional Ito calculus and a fractional version of the Girsanov transform, a no arbitrage price of the bond is recovered by solving a fractional version of the fundamental bond pricing equation. Besides this theoretical contribution, the paper proposes an estimation methodology based on the Kalman filter approach, which is applied to the US term structure of interest rates.Fractional bond pricing equation; fractional Brownian motion; fractional Ornstein-Uhlenbeck process; long memory; Kalman filter
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