740 research outputs found

    Envisioning future parenthood among bisexual, lesbian, and heterosexual women

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    For many individuals, becoming a parent is an important milestone. The current study examined attitudes and beliefs about parenting among a sample of 196 self-identified bisexual, lesbian, and heterosexual women. Results showed no differences by sexual orientation for women’s desires and intentions to have children, their idealization of parenthood, and perceptions of their parental self-efficacy (i.e., their ability to care for a child). In contrast, differences did emerge by sexual orientation in aspects such as partner expectations as well as professional intentions (i.e., wanting a permanent position before becoming a parent). Bisexual women tended to anticipate lower partner support compared to heterosexual women. Lesbian women, however, had a greater preference to work full-time during parenthood and wanted a permanent position before becoming a parent compared to both bisexual and heterosexual women. Implications are discussed of how bisexual women’s perceptions of parenthood are both similar to and distinct from lesbian and heterosexual women

    Dobrushin states in the \phi^4_1 model

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    We consider the van der Waals free energy functional in a bounded interval with inhomogeneous Dirichlet boundary conditions imposing the two stable phases at the endpoints. We compute the asymptotic free energy cost, as the length of the interval diverges, of shifting the interface from the midpoint. We then discuss the effect of thermal fluctuations by analyzing the \phi^4_1-measure with Dobrushin boundary conditions. In particular, we obtain a nontrivial limit in a suitable scaling in which the length of the interval diverges and the temperature vanishes. The limiting state is not translation invariant and describes a localized interface. This result can be seen as the probabilistic counterpart of the variational convergence of the associated excess free energy.Comment: 34 page

    Fourier Acceleration of Langevin Molecular Dynamics

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    Fourier acceleration has been successfully applied to the simulation of lattice field theories for more than a decade. In this paper, we extend the method to the dynamics of discrete particles moving in continuum. Although our method is based on a mapping of the particles' dynamics to a regular grid so that discrete Fourier transforms may be taken, it should be emphasized that the introduction of the grid is a purely algorithmic device and that no smoothing, coarse-graining or mean-field approximations are made. The method thus can be applied to the equations of motion of molecular dynamics (MD), or its Langevin or Brownian variants. For example, in Langevin MD simulations our acceleration technique permits a straightforward spectral decomposition of forces so that the long-wavelength modes are integrated with a longer time step, thereby reducing the time required to reach equilibrium or to decorrelate the system in equilibrium. Speedup factors of up to 30 are observed relative to pure (unaccelerated) Langevin MD. As with acceleration of critical lattice models, even further gains relative to the unaccelerated method are expected for larger systems. Preliminary results for Fourier-accelerated molecular dynamics are presented in order to illustrate the basic concepts. Possible extensions of the method and further lines of research are discussed.Comment: 11 pages, two illustrations included using graphic

    Raising the participation age in historical perspective : Policy learning from the past?

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    The raising of the participation age (RPA) to 17 in 2013 and 18 in 2015 marks a historic expansion of compulsory education. Despite the tendency of New Labour governments to eschew historical understanding and explanation, RPA was conceived with the benefit of an analysis of previous attempts to extend compulsion in schooling. This paper assesses the value of a historical understanding of education policy. The period from inception to the projected implementation of RPA is an extended one which has crossed over the change of government, from Labour to Coalition, in 2010. The shifting emphases and meanings of RPA are not simply technical issues but connect to profound historical and social changes. An analysis of the history of the raising of the school leaving age reveals many points of comparison with the contemporary situation. In a number of key areas it is possible to gain insights into the ways in which the study of the past can help to comprehend the present: the role of human capital, the structures of education, in curriculum development and in terms of preparations for change

    The Effects of Atmospheric Dispersion on High-Resolution Solar Spectroscopy

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    We investigate the effects of atmospheric dispersion on observations of the Sun at the ever-higher spatial resolutions afforded by increased apertures and improved techniques. The problems induced by atmospheric refraction are particularly significant for solar physics because the Sun is often best observed at low elevations, and the effect of the image displacement is not merely a loss of efficiency, but the mixing of information originating from different points on the solar surface. We calculate the magnitude of the atmospheric dispersion for the Sun during the year and examine the problems produced by this dispersion in both spectrographic and filter observations. We describe an observing technique for scanning spectrograph observations that minimizes the effects of the atmospheric dispersion while maintaining a regular scanning geometry. Such an approach could be useful for the new class of high-resolution solar spectrographs, such as SPINOR, POLIS, TRIPPEL, and ViSP

    Spin fluctuations in the quasi-two dimensional Heisenberg ferromagnet GdI_2 studied by Electron Spin Resonance

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    The spin dynamics of GdI_2 have been investigated by ESR spectroscopy. The temperature dependences of the resonance field and ESR intensity are well described by the model for the spin susceptibility proposed by Eremin et al. [Phys. Rev. B 64, 064425 (2001)]. The temperature dependence of the resonance linewidth shows a maximum similar to the electrical resistance and is discussed in terms of scattering processes between conduction electrons and localized spins.Comment: to be published in PR

    Anisotropic transport in unidirectional lateral superlattice around half-filling of the second Landau level

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    We have observed marked transport anisotropy in short period (a=92 nm) unidirectional lateral superlattices around filling factors nu=5/2 and 7/2: magnetoresistance shows a sharp peak for current along the modulation grating while a dip appears for current across the grating. By altering the ratio a/l (with l=sqrt{hbar/eB_perp} the magnetic length) via changing the electron density n_e, it is shown that the nu=5/2 anisotropic features appear in the range 6.6 alt a/l alt 7.2 varying their intensities, becoming most conspicuous at a/l simeq 6.7. The peak/dip broadens with temperature roughly preserving its height/depth up to 250 mK. Tilt experiments reveal that the structures are slightly enhanced by an in-plane magnetic field B_| perpendicular to the grating but are almost completely destroyed by B_| parallel to the grating. The observations suggest the stabilization of a unidirectional charge-density-wave or stripe phase by weak external periodic modulation at the second Landau level.Comment: REVTeX, 5 pages, 3 figures, Some minor revisions, Added notes and reference

    Observational Constraints on the Modified Gravity Model (MOG) Proposed by Moffat: Using the Magellanic System

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    A simple model for the dynamics of the Magellanic Stream (MS), in the framework of modified gravity models is investigated. We assume that the galaxy is made up of baryonic matter out of context of dark matter scenario. The model we used here is named Modified Gravity (MOG) proposed by Moffat (2005). In order to examine the compatibility of the overall properties of the MS under the MOG theory, the observational radial velocity profile of the MS is compared with the numerical results using the χ2\chi^2 fit method. In order to obtain the best model parameters, a maximum likelihood analysis is performed. We also compare the results of this model with the Cold Dark Matter (CDM) halo model and the other alternative gravity model that proposed by Bekenstein (2004), so called TeVeS. We show that by selecting the appropriate values for the free parameters, the MOG theory seems to be plausible to explain the dynamics of the MS as well as the CDM and the TeVeS models.Comment: 14 pages, 3 Figures, accepted in Int. J. Theor. Phy
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