31,283 research outputs found

    A New Solution of The Cosmological Constant Problems

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    We extend the usual gravitational action principle by promoting the bare cosmological constant (CC) from a parameter to a field which can take many possible values. Variation leads to a new integral constraint equation which determines the classical value of the effective CC that dominates the wave function of the universe. In a realistic cosmological model, the expected value of the effective CC, is calculated from measurable quantities to be O(t_U), as observed, where t_U is the present age of the universe in Planck units,. Any application of our model produces a falsifiable prediction for Λ\Lambda in terms of other measurable quantities. This leads to a specific falsifiable prediction for the observed spatial curvature parameter of Omega_k0=-0.0055. Our testable proposal requires no fine tunings or extra dark-energy fields but does suggest a new view of time and cosmological evolution.Comment: 5 pages; v3: version accepted by Phys. Rev. Let

    Optical enhancement of sensitivity in laser Doppler velocity systems

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    Utilization of optical enhancement techniques prevents loss of light by reflections at the photocathode of a photomultiplier and increases signal detection sensitivity

    Intending to be ethical: An examination of consumer choice in sweatshop avoidance

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    While much research in ethical consumption has focused on contexts such as food, this research explores ethical consumer decision-making in the context of intention to avoid sweatshop apparel. This research seeks to deepen the Theory of Planned Behavior with respect to the motivation and volitional stages underlying behavior. The findings of the research, based on 794 consumers, are novel and support an enriched framework which reveals that the role of attitude, subjective norm and perceived behavioral control are mediated by desire, intention and plan. The findings have implications for research seeking to address the ‘intention-behavior’ gap

    Antioxidant requirements of rats exposed to 100 % oxygen. Part 2 - Effects of dietary ascorbic acid

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    Dietary ascorbic acid effects as antioxidants in rats exposed to 100 percent oxyge

    The Local Effects of Cosmological Variations in Physical 'Constants' and Scalar Fields I. Spherically Symmetric Spacetimes

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    We apply the method of matched asymptotic expansions to analyse whether cosmological variations in physical `constants' and scalar fields are detectable, locally, on the surface of local gravitationally bound systems such as planets and stars, or inside virialised systems like galaxies and clusters. We assume spherical symmetry and derive a sufficient condition for the local time variation of the scalar fields that drive varying constants to track the cosmological one. We calculate a number of specific examples in detail by matching the Schwarzschild spacetime to spherically symmetric inhomogeneous Tolman-Bondi metrics in an intermediate region by rigorously construction matched asymptotic expansions on cosmological and local astronomical scales which overlap in an intermediate domain. We conclude that, independent of the details of the scalar-field theory describing the varying `constant', the condition for cosmological variations to be measured locally is almost always satisfied in physically realistic situations. The proof of this statement provides a rigorous justification for using terrestrial experiments and solar system observations to constrain or detect any cosmological time variations in the traditional `constants' of Nature.Comment: 30 pages, 3 figures; corrected typo

    Kinetics of non-equilibrium quasiparticle tunneling in superconducting charge qubits

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    We directly observe low-temperature non-equilibrium quasiparticle tunneling in a pair of charge qubits based on the single Cooper-pair box. We measure even- and odd-state dwell time distributions as a function of temperature, and interpret these results using a kinetic theory. While the even-state lifetime is exponentially distributed, the odd-state distribution is more heavily weighted to short times, implying that odd-to-even tunnel events are not described by a homogenous Poisson process. The mean odd-state dwell time increases sharply at low temperature, which is consistent with quasiparticles tunneling out of the island before reaching thermal equilibrium.Comment: Replaced Figure 1 with color version, corrected more typos. Version submitted to PR

    V. problem presentation and advice-giving on a home birth helpline

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    The rate of home births in the UK is very low (around 2%) and many women who would like to give birth at home find it impossible to get midwifery cover or are advised of medical contraindications. The Home Birth Helpline offers support and expertise for women in this situation. Based on the analysis of 80 recorded calls, this article uses conversation analysis (CA) to explore how callers present their reason for calling the helpline, and what this shows about the culturally shared medicalized culture of birth. This research is an example of feminist CA in that it contributes both to the study of childbirth as a key women's health issue and to the study of helpline interaction from a conversation analytic perspectiv

    The First World War Centenary in the UK: ‘A Truly National Commemoration’?

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    Prime Minister David Cameron has called for ‘a truly national commemoration of the First World War’. This article shows this to be problematic, politicised and contested. This is in part due to the elision of English and British histories. Scottish, Welsh and Irish responses are noted, and the role and commemorations of ‘our friends in the Commonwealth’. There are tensions around interpretations of empire and race. There has been a failure to appreciate that the debates about the legacies of the First World War are deeply entangled with those of colonialism

    The geomorphological setting of some of Scotland's east coast freshwater mills: a comment on Downward and Skinner (2005) ‘Working rivers: the geomorphological legacy...’

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    Many of the water mills on Scotland's east coast streams, unlike those discussed recently by Downward and Skinner (2005 Area 37 138–47), are found in predominantly bedrock reaches immediately downstream of knickpoints (i.e. bedrock steps). Bedrock knickpoints in the lower reaches of Scottish rivers are a widespread fluvial response to the glacio-isostatic rebound of northern Britain. These steps in the river profile propagate headward over time, but for intervals of a few centuries or so they are sufficiently stable to be exploited for the elevational fall necessary to power the mill wheel. Many of these mills were apparently powered by ‘run-of-the-river’, as are some today that formerly had mill dams. The typical lack of sediment storage along the erosional lower reaches of many Scottish rivers means that failure of mill structures in Scotland will probably have less dramatic geomorphological and management implications than those suggested by Downward and Skinner for southern English rivers
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