6,168 research outputs found

    Female reproductive strategy predicts preferences for sexual dimorphism in male faces

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    The aim of the current studies was to test an assumption that variation in female preferences for sexually dimorphic male facial characteristics reflects strategic optimisation of investment in offspring. A negative relationship was predicted between ideal number of children and preferences for masculine male face shapes, as the benefits of securing paternal investment should outweigh the benefits of securing good genes as the costs of raising offspring increase. In Study 1 desired number of children and preferences for masculine face shapes were compared in a sample of female students. In study 2, the prediction was tested in a sample with a wider age profile while controlling for relationship status. Preferences for explicit partner characteristics were also assessed. The prediction was supported: women who desired a higher number of children preferred more feminine male face shapes and ranked cues to investment of parental care over cues to immunocompetence in a partner more highly than those who desired fewer children. Results indicate that female mate preferences vary with reproductive strategy and support assumptions that preferences for feminine male faces reflect preferences for “good dads”

    Orbital magnetoelectric coupling in band insulators

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    Magnetoelectric responses are a fundamental characteristic of materials that break time-reversal and inversion symmetries (notably multiferroics) and, remarkably, of "topological insulators" in which those symmetries are unbroken. Previous work has shown how to compute spin and lattice contributions to the magnetoelectric tensor. Here we solve the problem of orbital contributions by computing the frozen-lattice electronic polarization induced by a magnetic field. One part of this response (the "Chern-Simons term") can appear even in time-reversal-symmetric materials and has been previously shown to be quantized in topological insulators. In general materials there are additional orbital contributions to all parts of the magnetoelectric tensor; these vanish in topological insulators by symmetry and also vanish in several simplified models without time-reversal and inversion those magnetoelectric couplings were studied before. We give two derivations of the response formula, one based on a uniform magnetic field and one based on extrapolation of a long-wavelength magnetic field, and discuss some of the consequences of this formula.Comment: 13 page

    Dynamical model of the dielectric screening of conjugated polymers

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    A dynamical model of the dielectric screening of conjugated polymers is introduced and solved using the density matrix renormalization group method. The model consists of a line of quantized dipoles interacting with a polymer chain. The polymer is modelled by the Pariser-Parr-Pople (P-P-P) model. It is found that: (1) Compared to isolated, unscreened single chains, the screened 1Bu- exciton binding energy is typically reduced by ca. 1 eV to just over 1 eV; (2) Covalent (magnon and bi-magnon) states are very weakly screened compared to ionic (exciton) states; (3) Screening of the 1Bu- exciton is closer to the dispersion than solvation limit.Comment: 12 pages, 2 figure

    Continuum Annulus Amplitude from the Two-Matrix Model

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    An explicit expression for continuum annulus amplitudes having boundary lengths 1\ell_{1} and 2\ell_{2} is obtained from the two-matrix model for the case of the unitary series; (p,q)=(m+1,m)(p,q) = (m + 1, m). In the limit of vanishing cosmological constant, we find an integral representation of these amplitudes which is reproduced, for the cases of the m=2 (c=0)m = 2~(c=0) and the m (c=1)m \rightarrow \infty~(c=1), by a continuum approach consisting of quantum mechanics of loops and a matter system integrated over the modular parameter of the annulus. We comment on a possible relation to the unconventional branch of the Liouville gravity.Comment: 9 pages, OU-HET 190, revised version. A part of the conclusions has been corrected. A new result on integral representation of the annulus amplitudes has been adde

    A Generalization of Martin's Axiom

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    We define the 1.5\aleph_{1.5} chain condition. The corresponding forcing axiom is a generalization of Martin's Axiom and implies certain uniform failures of club--guessing on ω1\omega_1 that don't seem to have been considered in the literature before.Comment: 36 page

    First principles theory of fluctuations in vortex liquids and solids

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    Consistent perturbation theory for thermodynamical quantities in type II superconductors in magnetic field at low temperatures is developed. It is complementary to the existing expansion valid at high temperatures. Magnetization and specific heat are calculated to two loop order and compare well to existing Monte Carlo simulations and experiments.Comment: 3 .ps fig. In press Phys. Rev.

    Outcomes important to patients with non-infectious posterior segment-involving uveitis:a qualitative study

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    Objective: Uveitis, a group of disorders characterised by intraocular inflammation, causes 10–15% of total blindness in the developed world. The most sight-threatening forms of non-infectious uveitis are those affecting the posterior segment of the eye, collectively known as posterior-segment involving uveitis (PSIU). Numerous different clinical outcomes have been used in trials evaluating treatments for PSIU but these may not represent patients’ and carers’ concerns. Therefore, the aims of this study were to understand the impact of PSIU on adult patients’ and carers’ lives, and to explore what outcomes of treatment are important to them.Methods: Four focus group discussions were undertaken to understand the perspectives of adult patients (n=18) and carers (n=10) with PSIU. Participants were grouped according to whether or not their uveitis was complicated by the sight-threatening condition uveitic macular oedema (UMO). Discussions were audio recorded, transcribed and analysed using the framework analytical approach. Outcomes were identified and grouped into outcome domains. Results: Eleven core domains were identified as important to patients and carers undergoing treatment for PSIU comprising: (1) visual function, (2) symptoms, (3) functional ability, (4) impact on relationships, (5) financial impact, (6) psychological morbidity and emotional well-being (7) psychosocial adjustment to uveitis, (8) doctor/patient/interprofessional relationships and access to health care, (9) treatment burden, (10) treatment side effects, (11) disease control.Conclusion: The domains identified represent patients and carers experience and perspectives and can be used to reflect on outcomes assessed in PSIU. They will directly inform the development of a core outcome set for PSIU clinical trials.Ethical approval: Ethical approval was obtained from the United Kingdom National Research Ethics Service (Reference 17-WM-0111).<br/
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