15,067 research outputs found

    Why is Long-Horizon Equity Less Risky? A Duration-Based Explanation of the Value Premium

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    This paper proposes a dynamic risk-based model that captures the high expected returns on value stocks relative to growth stocks, and the failure of the capital asset pricing model to explain these expected returns. To model the difference between value and growth stocks, we introduce a cross-section of long-lived firms distinguished by the timing of their cash flows. Firms with cash flows weighted more to the future have high price ratios, while firms with cash flows weighted more to the present have low price ratios. We model how investors perceive the risks of these cash flows by specifying a stochastic discount factor for the economy. The stochastic discount factor implies that shocks to aggregate dividends are priced, but that shocks to the time-varying price of risk are not. As long-horizon equity, growth stocks covary more with this time-varying price of risk than value stocks, which covary more with shocks to cash flows. When the model is calibrated to explain aggregate stock market behavior, we find that it can also account for the observed value premium, the high Sharpe ratios on value stocks relative to growth stocks, and the outperformance of value (and underperformance of growth) relative to the CAPM.

    The Measure of Poverty: A Boston Indicators Project Special Report

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    Examines Boston's poverty rate by race/ethnicity, family structure, education, and geography; income inequality; demand for safety-net programs; and how the high cost of living and budget cuts affect vulnerable households and those below the poverty line

    City of Ideas: Reinventing Boston's Innovation Economy: The Boston Indicators Report 2012

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    Analyzes indicators of the city's economic, social, and technological progress; potential for creating innovative solutions to global and national challenges; and complexities, disparities, and weaknesses in the indicators and innovation economy paradigm

    High index top layer for multimaterial coatings

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    For application in future cryogenically cooled gravitational wave detectors, the thermal noise of low absorbing mirror coatings has to be reduced. The development of low mechanical and optical loss materials is challenging, but thermal noise reduction can be significantly supported by using a multimaterial coating design. We analyze the possible improvement of the total (optical and mechanical) loss of a three-material based coating obtained by optimizing the properties of the top layer of the coating stack. A top-layer material with sufficiently high refractive index could have a significantly higher optical and mechanical loss than currently used tantala, while still enabling reduction of the total coating loss. Restrictions on possible top-layer material properties are made, and the option of a crystalline top layer is discussed

    Effect of stress and temperature on the optical properties of silicon nitride membranes at 1550 nm

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    Future gravitational-wave detectors operated at cryogenic temperatures are expected to be limited by thermal noise of the highly reflective mirror coatings. Silicon nitride is an interesting material for such coatings as it shows very low mechanical loss, a property related to low thermal noise, which is known to further decrease under stress. Low optical absorption is also required to maintain the low mirror temperature. Here, we investigate the effect of stress on the optical properties at 1,550 nm of silicon nitride membranes attached to a silicon frame. Our approach includes the measurement of the thermal expansion coefficient and the thermal conductivity of the membranes. The membrane and frame temperatures are varied, and translated into a change in stress using finite element modeling. The resulting product of the optical absorption and thermo-optic coefficient (dn/dT) is measured using photothermal common-path interferometry

    Exploring Body Comparison Tendencies: Women Are Self-Critical Whereas Men Are Self-Hopeful

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    Our study examined similarities and differences in women’s and men’s comparison tendencies and perfection beliefs when evaluating their face, body shape, and physical abilities, as well as how these tendencies and beliefs relate to their body esteem. College students (90 women and 88 men) completed the Body Esteem Scale (Franzoi & Shields, 1984) and answered questions concerning their social comparison and temporal comparison tendencies related to face, body shape, and physical abilities evaluations as well as personal perfection body beliefs. As predicted, women were more likely than men to compare their face and bodies to other same-sex persons whom they perceived as having either similar or better physical qualities than themselves in those body domains, with their most likely comparison tendency being upward social comparison. More men than women held body-perfection beliefs for all three body domains, and men were most likely to rely on future temporal comparison when evaluating their body shape. Comparison tendencies and perfection beliefs also were differentially related to women\u27s and men\u27s body esteem; whereas women rely on self-critical social comparison strategies associated with negative body esteem, men’s comparison strategies and perfection beliefs are more self-hopeful. Implications for practitioners treating body-image issues are discussed

    Beyond Chandra - the X-ray Surveyor

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    Over the past 16 years, NASA's Chandra X-ray Observatory has provided an unparalleled means for exploring the universe with its half-arcsecond angular resolution. Chandra studies have deepened our understanding of galaxy clusters, active galactic nuclei, galaxies, supernova remnants, planets, and solar system objects addressing almost all areas of current interest in astronomy and astrophysics. As we look beyond Chandra, it is clear that comparable or even better angular resolution with greatly increased photon throughput is essential to address even more demanding science questions, such as the formation and subsequent growth of black hole seeds at very high redshift; the emergence of the first galaxy groups; and details of feedback over a large range of scales from galaxies to galaxy clusters. Recently, NASA Marshall Space Flight Center, together with the Smithsonian Astrophysical Observatory, has initiated a concept study for such a mission named the X-ray Surveyor. This study starts with a baseline payload consisting of a high resolution X-ray telescope and an instrument set which may include an X-ray calorimeter, a wide-field imager and a dispersive grating spectrometer and readout. The telescope would consist of highly nested thin shells, for which a number of technical approaches are currently under development, including adjustable X-ray optics, differential deposition, and modern polishing techniques applied to a variety of substrates. In many areas, the mission requirements would be no more stringent than those of Chandra, and the study takes advantage of similar studies for other large area missions carried out over the past two decades. Initial assessments indicate that such an X-ray mission is scientifically compelling, technically feasible, and worthy of a high rioritization by the next American National Academy of Sciences Decadal Survey for Astronomy and Astrophysics.Comment: 6 pages, 6 figures, paper 9510-01 presented at SPIE Europe, Prague, April 201

    Disability and football

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    Football rhetoric in recent years has emphasised the notion of the ‘football family’ as an inclusive concept, arguing that the global nature of football can be harnessed as a powerful force for positive social change. If this ‘footballing family’ analogy is applied to disabled people, they might be considered to have moved from being the relative hidden away in the corner at family events that nobody talks to (or about) to being the strange and eccentric relative whose right to be present is at least acknowledged if not fully understood. This chapter will outline briefly the history of disability and football, whilst identifying some of the issues faced by disabled people and investigating the increasing involvement of disabled people as both players and spectators
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