45,688 research outputs found

    The Birth Control Divide : U. S. Press Coverage of Contraception, 1873-2013

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    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

    Zero-Variance Zero-Bias Principle for Observables in quantum Monte Carlo: Application to Forces

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    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 H2_2,LiH, and Li2_2 molecules are presented. Spectroscopic constants ReR_e (equilibrium distance) and ωe\omega_e (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

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    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 R/−/(//sun/)R/-/(//sun/)=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.

    Alignment of oblique rotators

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    Pulsars with torque aligning magnetic moment with spin axi

    CP violation conditions in N-Higgs-doublet potentials

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    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 ZZ. v3: Eqs.(28)-(31) correcte
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