2,255 research outputs found
Effective Hamiltonians for atoms in very strong magnetic fields
We propose three effective Hamiltonians which approximate atoms in very
strong homogeneous magnetic fields modelled by the Pauli Hamiltonian, with
fixed total angular momentum with respect to magnetic field axis. All three
Hamiltonians describe electrons and a fixed nucleus where the Coulomb
interaction has been replaced by -dependent one-dimensional effective
(vector valued) potentials but without magnetic field. Two of them are solvable
in at least the one electron case. We briefly sketch how these Hamiltonians can
be used to analyse the bottom of the spectrum of such atoms.Comment: 43 page
Modeling magnetohydrodynamics and non equilibrium SoHO/UVCS line emission of CME shocks
We provide a guideline to interpret the UVCS emission lines (in particular O
VI and Si XII) during shock wave propagation in the outer solar corona. We use
a numerical MHD model performing a set of simulations of shock waves generated
in the corona and from the result we compute the plasma emission for the O VI
and Si XII including the effects of NEI. We analyze the radiative and spectral
properties of our model with the support of a detailed radiation model
including Doppler dimming and an analytical model for shocks, and, finally, we
synthesize the expected O VI 1032A line profile. We explain several spectral
features of the observations like the absence of discontinuities in the O VI
emission during the shock passage, the brightening of Si XII emission and the
width of the lines. We use our model also to give very simple and general
predictions for the strength of the line wings due to the ions shock heating
and on the line shape for Limb CMEs or Halo CMEs. The emission coming from
post-shock region in the solar corona roughly agrees with the emission from a
simple planar and adiabatic shock, but the effect of thermal conduction and the
magnetic field may be important depending on the event parameters. Doppler
dimming significantly influences the O VI emission while Si XII line brightens
mainly because of the shock compression. Significant shock heating is
responsible for the wide and faint component of the O VI line usually observed
which may be taken as a shock signature in the solar corona.Comment: 11 pages, 12 figures, 2 appendixe
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Workplace Discrimination of the African American Woman
The combination of racism and sexism has severely limited the progress of the African American woman, to this day black women are still discriminated against due to their color and gender. The discrimination is especially prevalent in the workplace, where black women earn significantly less, and receive fewer opportunities than similarly qualified candidates
Salary Inversion in Business Schools: Does a Rising Tide Lift All Boats?
The paper analyzes AACSB salary survey information from 1979 to 2008. The question addressed in this analysis is whether salary inversion is widespread across the three business disciplines of accounting, economics, and finance. We find limited evidence of mean level inversions, which is concentrated in recent years. Stochastic dominance methods confirm these results. We also develop a measure of salary dominance based on comparing the distribution of reported salaries. This statistic shows a significant trend towards salary inversion in finance and accounting
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