7,050 research outputs found

    Stem Cells

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    Supersymmetric Electroweak Baryogenesis

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    We re-examine the generation of the baryon asymmetry in the minimal supersymmetric standard model (MSSM) during the electroweak phase transition. We find that the dominant source for baryogenesis arises from the chargino sector. The CP-violation comes from the complex phase in the mu parameter, which provides CP-odd contributions to the particle dispersion relations. This leads to different accelerations for particles and antiparticles in the wall region which, combined with diffusion, leads to the separation of Higgsinos and their antiparticles in the front of the wall. These asymmetries get transported to produce perturbations in the left-handed chiral quarks, which then drive sphaleron interactions to create the baryon asymmetry. We present a complete derivation of the semiclassical WKB formalism, including the chargino dispersion relations and a self-consistent derivation of the diffusion equations starting from semiclassical Boltzmann equations for WKB-excitations. We stress the advantages of treating the transport equations in terms of the manifestly gauge invariant physical energy and kinetic momentum, rather than in the gauge variant canonical variables used in previous treatments. We show that a large enough baryon asymmetry can be created for the phase of the complex mu parameter as small as ~ 0.001, which is consistent with bounds from the neutron electric dipole moment.Comment: 54 pages, 3 figure

    Second Mortgages and Household Saving

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    Second mortgages accounted for 10.8% of the stock of outstanding mortgage debt at the end of 1987, up from 3.6% at the beginning of the 198Os. This paper investigates the determinants of second mortgage borrowing and the characteristics of second mortgage borrowers. We first calculate the outstanding stock of home equity that remains to be borrowed against on tax-preferred terms, recognizing the limits on interest deductions in the 1986 Tax Reform Act and the 1987 Omnibus Budget Reconciliation Act. Despite these limits, we estimate that more than two trillion dollars of housing equity remains to be borrowed against by current homeowners. We then present cross-sectional evidence suggesting that households who obtain second mortgages after purchasing a home ace less wealthy than other households with similar characteristics. Each dollar of second mortgage borrowing is associated with a seventy-five cent reduction in household net worth. While these results cannot be given a causal interpretation, they are consistent with the view that increased access to second mortgages has reduced personal saving.

    Seeing the light – finding the poetic content of design objects

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    This paper presents the process and initial results of a research through design project attempting to understand the poetic qualities of design objects. This exploration forms part of a PhD study addressing design artefacts as poetic objects - objects that both embed and conjure memory, association and imagination. The research examines the ways in which design objects can be poetic and how designers actively and knowingly use objects to poetic effect. It is proposed that the poetic content of design artefacts can be located on a continuum ranging from the experiential - relating to how we perceive things - to the reflective and cultural. What unites these levels is the capacity of design objects to reveal and change our way of looking at things. The practice uses the design of lighting as a vehicle for exploring the poetic meaning of designed objects more generally. Starting with the notion that lights do more than provide light, the current phase of practice examines the ways in which luminaires can mediate how we perceive and experience light and explores, in particular, the more nuanced and ephemeral qualities of light that escape conscious attention

    The Circe

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    The new girl -a term catholic throughout all grammar schools -was quite pretty. Naturally, being twelve and susceptible, I promptly fell in love with her. \u27It was my first affair

    Child poverty in the UK since 1998-99: lessons from the past decade

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    As a result of the Child Poverty Act (2010), current and future governments are committed to reducing the rate of relative income child poverty in the UK to 10% by 2020-21. This paper looks in detail at the progress made towards this goal under the previous Labour administrations. Direct tax and benefit reforms are very important in explaining at least three things: the large overall reduction in child poverty since 1998-99; the striking slowdown in progress towards the child poverty targets between 2004-05 and 2007-08; and some of the variation in child poverty trends between different groups of children. However, some of the child poverty-reducing impact of those reforms acted simply to stop child poverty rising as real earnings grew over the period, which increases median income and thus the relative poverty line. The performance of parents in the labour market is important too: between regions, parental employment and child poverty trends are closely related; the overall reduction in child poverty since 1998-99 has been helped by higher lone parent employment rates; and the overall rise in child poverty since 2004-05 has been most concentrated on children of one-earner couples, whose real earnings have fallen.

    A Defense Of Imprecise Credences In Inference And Decision Making1

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111950/1/j.1520-8583.2010.00194.x.pd
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