44,439 research outputs found
The Birth Control Divide : U. S. Press Coverage of Contraception, 1873-2013
For more than 140 years, religious, medical, legislative, and legal institutions have contested the issue of contraception. In this conversation, predominantly male voices have attached reproductive rights to tangential moral and political matters, revealing an ongoing, systematic attempt to regulate human bodies, especially those of women. This analysis of 1873-2013 press coverage of contraception in the New York Times, the Los Angeles Times, and the Chicago Tribune shows a division between institutional ideology and real-life experience; women’s reproductive rights are negotiable. Although journalists often reported that contraception was a factor in the everyday life of women and men, press accounts also showed religious, medical, legislative, and legal institutions debating whether it should be. Contraception originally was predominately viewed as a practice of prostitutes (despite evidence to the contrary) but became a part of everyday life. The battle has slowly evolved into one about the Affordable Care Act, religious freedom, morality, and employer rights. What did not significantly change over the 140-year period are larger cultural and ideological structures; these continue to be dominated by men, who retain power over women’s bodies
CP violation conditions in N-Higgs-doublet potentials
Conditions for CP violation in the scalar potential sector of general
N-Higgs-doublet models (NHDMs) are analyzed from a group theoretical
perspective. For the simplest two-Higgs-doublet model (2HDM) potential, a
minimum set of conditions for explicit and spontaneous CP violation is
presented. The conditions can be given a clear geometrical interpretation in
terms of quantities in the adjoint representation of the basis transformation
group for the two doublets. Such conditions depend on CP-odd pseudoscalar
invariants. When the potential is CP invariant, the explicit procedure to reach
the real CP-basis and the explicit CP transformation can also be obtained. The
procedure to find the real basis and the conditions for CP violation are then
extended to general NHDM potentials. The analysis becomes more involved and
only a formal procedure to reach the real basis is found. Necessary conditions
for CP invariance can still be formulated in terms of group invariants: the
CP-odd generalized pseudoscalars. The problem can be completely solved for
three Higgs-doublets.Comment: RevTeX4 used. Minor modifications, in particular, the parameter
counting of . v3: Eqs.(28)-(31) correcte
Zero-Variance Zero-Bias Principle for Observables in quantum Monte Carlo: Application to Forces
A simple and stable method for computing accurate expectation values of
observable with Variational Monte Carlo (VMC) or Diffusion Monte Carlo (DMC)
algorithms is presented. The basic idea consists in replacing the usual
``bare'' estimator associated with the observable by an improved or
``renormalized'' estimator. Using this estimator more accurate averages are
obtained: Not only the statistical fluctuations are reduced but also the
systematic error (bias) associated with the approximate VMC or (fixed-node) DMC
probability densities. It is shown that improved estimators obey a
Zero-Variance Zero-Bias (ZVZB) property similar to the usual Zero-Variance
Zero-Bias property of the energy with the local energy as improved estimator.
Using this property improved estimators can be optimized and the resulting
accuracy on expectation values may reach the remarkable accuracy obtained for
total energies. As an important example, we present the application of our
formalism to the computation of forces in molecular systems. Calculations of
the entire force curve of the H,LiH, and Li molecules are presented.
Spectroscopic constants (equilibrium distance) and (harmonic
frequency) are also computed. The equilibrium distances are obtained with a
relative error smaller than 1%, while the harmonic frequencies are computed
with an error of about 10%
The Edge of the Galactic Disc
As part of a stellar population sampling program, a series of photometric
probes at various field sizes and depths have been obtained in a low extinction
window in the galactic anticentre direction. Such data set strong constraints
on the radial structure of the disc. At the forefront of this "drilling"
program, very deep CCD frames probe the most external parts of the disc. Over
the whole effective magnitude range (18 to 25), all contributions in the
statistics which should be expected from old disc stars beyond 6 kpc vanish,
although such stars dominate by far at distances less than 5 kpc. This is the
signature of a sharp cut-off in the star density: the edge of the galactic disc
between 5.5 and 6 kpc. As a consequence, the galactic radius does not exceed 14
kpc (assuming =8.5). Colours of elliptical galaxies measured in
the field rule out the risk of being misled by undetected extinction.Comment: 8 pages, Besancon Observatory preprint n.
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