68,227 research outputs found

    The Kepler-19 System: A Transiting 2.2 R_⊕ Planet and a Second Planet Detected via Transit Timing Variations

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    We present the discovery of the Kepler-19 planetary system, which we first identified from a 9.3 day periodic transit signal in the Kepler photometry. From high-resolution spectroscopy of the star, we find a stellar effective temperature T_(eff) = 5541 ± 60 K, a metallicity [Fe/H] = –0.13 ± 0.06, and a surface gravity log(g) = 4.59 ± 0.10. We combine the estimate of T_(eff) and [Fe/H] with an estimate of the stellar density derived from the photometric light curve to deduce a stellar mass of M_*= 0.936 ± 0.040 M_☉ and a stellar radius of R_* = 0.850 ± 0.018 R_☉ (these errors do not include uncertainties in the stellar models). We rule out the possibility that the transits result from an astrophysical false positive by first identifying the subset of stellar blends that reproduce the precise shape of the light curve. Using the additional constraints from the measured color of the system, the absence of a secondary source in the high-resolution spectrum, and the absence of a secondary source in the adaptive optics imaging, we conclude that the planetary scenario is more than three orders of magnitude more likely than a blend. The blend scenario is independently disfavored by the achromaticity of the transit: we measure a transit depth with Spitzer at 4.5 μm of 547^(+113)_(–110) ppm, consistent with the depth measured in the Kepler optical bandpass of 567 ± 6 ppm (corrected for stellar limb darkening). We determine a physical radius of the planet Kepler-19b of R_p = 2.209 ± 0.048 R_⊕; the uncertainty is dominated by uncertainty in the stellar parameters. From radial velocity observations of the star, we find an upper limit on the planet mass of 20.3 M_⊕, corresponding to a maximum density of 10.4 g cm^(–3). We report a significant sinusoidal deviation of the transit times from a predicted linear ephemeris, which we conclude is due to an additional perturbing body in the system. We cannot uniquely determine the orbital parameters of the perturber, as various dynamical mechanisms match the amplitude, period, and shape of the transit timing signal and satisfy the host star's radial velocity limits. However, the perturber in these mechanisms has a period ≾ 160 days and mass ≾ 6 M_(Jup), confirming its planetary nature as Kepler-19c. We place limits on the presence of transits of Kepler-19c in the available Kepler data

    Teaching Business Ethics: The Departmental Perspective

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    Money and mental contents

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    It can be hard to see where money fits in the world. Money seems both real and imaginary, since it has obvious causal powers, but is also, just as obviously, something humans have just made up. Recent philosophical accounts of money have declared it to be real, but for very different reasons. John Searle and Francesco Guala disagree over whether money is just whatever acts like money, or just whatever people believe to be money. In developing their accounts of institutions as a part of social reality, each uses money as a paradigm institution, but they disagree on how institutions exist. Searle argues that the institution of money belongs to an ontological level separate from the physical world, held up by the collective intentions of a group, while Guala claims that money is a part of the ordinary physical world and is just whatever performs a “money-like function” in a group, regardless of what that group believes about it. Here, we argue that any purely functional account like Guala’s will be unable to capture the distinctive phenomenon of money, since monetary transactions are defined by the attitudes transactors hold toward them. Money will be obscured or misidentified if defined functionally. As we go on to show by examining recent work by Smit et al., belief in money does not require taking on all of Searle’s ontological commitments, but money and mental contents will stand or fall together

    Managed Care Provider Volume

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    There is considerable evidence that patients that are treated by high volume physicians and hospitals have better health outcomes than patients treated by low volume physicians and hospitals. Thus, as an indirect measure of quality differences between managed care and traditional fee-for-service insurance, we compare the average provider volume of cancer patients covered by these two types of plans. We find that managed care patients tend to be treated by lower volume providers and that the magnitude of the differences varies by the particular cancer and managed care plan.

    The Full Employment Mandate of the Federal Reserve: Its Origins and Importance

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    As we approach the 40th anniversary of the landmark Humphrey-Hawkins Act, this report underscores how the Federal Reserve's full employment mandate has made the Fed more accountable to working people. The report first traces the historical origins of the full employment mandate and highlights the pivotal but little-known role racial justice activists played in its creation. From the 1930s and through the rise of the civil rights movement, racial justice activists including Coretta Scott King, called for a coordinated federal effort to attain full employment. They envisioned an economy where every person who seeks employment can secure a job. King joined Congressional leaders Augustus Hawkins and Hubert Humphrey in eventually passing the landmark 1978 Full Employment and Balanced Growth Act (Humphrey-Hawkins) which legally required the Fed to pursue maximum employment.The report then turns to Federal Reserve monetary policy in the 1990's which offers an instructive model of what a full employment economy can look like. This real-world case study from our recent history shows that when labor markets tighten, workers begin to see broad-based wage gains, and persistent economic inequalities are reduced. Finally, the report underscores the continued importance of the full employment mandate today while providing an overview of proposed policies to eliminate or significantly curtail its effectiveness. In light of these findings, this report calls on Federal Reserve policymakers to use all tools at their disposal to fully realize the Fed's full employment mandate. Members of Congress must publicly affirm the importance of full employment while committing to reject any efforts to weaken or eliminate the full employment mandate. In particular, the Senate must reject nominees to the Board of Governors who have called for the narrowing of the Fed's mandate or who support policies that would undermine the Fed's ability to pursue full employment

    On the asymptotic growth of Bloch-Kato-Shafarevich-Tate groups of modular forms over cyclotomic extensions

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    We study the asymptotic behaviour of the Bloch-Kato-Shafarevich-Tate group of a modular form f over the cyclotomic Zp-extension of Q under the assumption that f is non-ordinary at p. In particular, we give upper bounds of these groups in terms of Iwasawa invariants of Selmer groups defined using p-adic Hodge Theory. These bounds have the same form as the formulae of Kobayashi, Kurihara and Sprung for supersingular elliptic curves.Comment: To appear in Canad. J. Mat

    Continuing bonds with the living : bereaved parents’ narratives of their emotional relationship with their children

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    © 2017 Cruse Bereavement Care.The death of a child can be seen as one of the most devastating experiences for parents which can result in a unique and enduring grief. Parents with surviving children face the task of navigating their own grief while continuing to parent. This narrative inquiry explores bereaved parents’ stories of their emotional relationship with their surviving children. Parents told stories of emotional connection and disconnection with surviving children, influenced by the competing and potentially incompatible tasks of ‘parenting’ and ‘grieving’. The need for a relational focus to bereavement research and practice is highlighted. The findings demonstrate the need for clinicians to provide i) parents an opportunity to explore their sometimes contradicting and troubling experiences of grief and parenting and ii) children with support to make sense of their experiences in relation to the parent-child relationship.Peer reviewe

    Separation of Variables and the Computation of Fourier Transforms on Finite Groups, II

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    We present a general diagrammatic approach to the construction of efficient algorithms for computing the Fourier transform of a function on a finite group. By extending work which connects Bratteli diagrams to the construction of Fast Fourier Transform algorithms %\cite{sovi}, we make explicit use of the path algebra connection to the construction of Gel'fand-Tsetlin bases and work in the setting of quivers. We relate this framework to the construction of a {\em configuration space} derived from a Bratteli diagram. In this setting the complexity of an algorithm for computing a Fourier transform reduces to the calculation of the dimension of the associated configuration space. Our methods give improved upper bounds for computing the Fourier transform for the general linear groups over finite fields, the classical Weyl groups, and homogeneous spaces of finite groups, while also recovering the best known algorithms for the symmetric group and compact Lie groups.Comment: 53 pages, 5 appendices, 34 figure

    Euler systems for GSp(4)

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    We construct an Euler system for Galois representations associated to cohomological cuspidal automorphic representations of the group GSp(4), using the pushforwards of Eisenstein classes for GL(2) x GL(2).Comment: 41 pages. Revised version -- main theorem now applies in all cohomological weight
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