7,642 research outputs found

    No Small Change: Pension Funds and Corporate Engagement

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    [Excerpt] At its best corporate engagement offers a long-term view of value that both promotes higher environmental, social, and governance standards and adds share value, thus providing long-term benefits to future pension beneficiaries. At its worst it diverts the attention of pension fund officials from their primary responsibility of ensuring the retirement benefits of their members, and encourages pension funds to usurp the rightful responsibilities of corporate managers. This book examines corporate engagement and its impacts on firms in an effort to see how the potential from this newly emerging force is being realized

    Storage Capacity of Extremely Diluted Hopfield Model

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    The storage capacity of the extremely diluted Hopfield Model is studied by using Monte Carlo techniques. In this work, instead of diluting the synapses according to a given distribution, the dilution of the synapses is obtained systematically by retaining only the synapses with dominant contributions. It is observed that by using the prescribed dilution method the critical storage capacity of the system increases with decreasing number of synapses per neuron reaching almost the value obtained from mean-field calculations. It is also shown that the increase of the storage capacity of the diluted system depends on the storage capacity of the fully connected Hopfield Model and the fraction of the diluted synapses.Comment: Latex, 14 pages, 4 eps figure

    The role of community partners in urban investments

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    Institutional investors seeking to deploy capital to underserved areas do not have either the time or the expertise to actively manage these specialized investments. Investment vehicles intervene by using their financial expertise to pool assets and lower transaction costs. Community partners, in turn, link the investment vehicle to the neighborhood. This paper develops a typology of community partners and their unique characteristics that enable them to overcome information asymmetries in certain markets. The paper also discusses the business models that establish the relationship between the investment vehicle and community partner to highlight strengths of the different models for delivering community transformation.Community development

    Letter from Dr. Michael Hebb, Woodlawn Medical Clinic, to Geraldine Ferraro

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    Letter from Dr. Michael Hebb, of the Woodlawn Medical Clinic in Canada, to Geraldine Ferraro.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_international/1370/thumbnail.jp

    Infrared absorption in doped semiconductors due to direct intersubband transitions

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    Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1993.Includes bibliographical references (leaves 68-70).by Jeffrey Paul Hebb.M.S

    Investment intermediaries in economic development: Linking public pension funds to urban revitalization

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    It is difficult for large investors, such as pension funds, to make investments in EDMs because they must make very large investments. The investments in communities of need, however, are usually small. The most successful strategy to overcome these two problems is for investors to work in concert with intermediaries that can aggregate the investments and community partners that understand both the need of communities and know how to tell “the story” to investors.

    An Improved Method for Estimating the Masses of Stars with Transiting Planets

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    To determine the physical parameters of a transiting planet and its host star from photometric and spectroscopic analysis, it is essential to independently measure the stellar mass. This is often achieved by the use of evolutionary tracks and isochrones, but the mass result is only as reliable as the models used. The recent paper by Torres et al (2009) showed that accurate values for stellar masses and radii could be obtained from a calibration using T_eff, log g and [Fe/H]. We investigate whether a similarly good calibration can be obtained by substituting log rho - the fundamental parameter measured for the host star of a transiting planet - for log g, and apply this to star-exoplanet systems. We perform a polynomial fit to stellar binary data provided in Torres et al (2009) to obtain the stellar mass and radius as functions of T_eff, log rho and [Fe/H], with uncertainties on the fit produced from a Monte Carlo analysis. We apply the resulting equations to measurements for seventeen SuperWASP host stars, and also demonstrate the application of the calibration in a Markov Chain Monte Carlo analysis to obtain accurate system parameters where spectroscopic estimates of effective stellar temperature and metallicity are available. We show that the calibration using log rho produces accurate values for the stellar masses and radii; we obtain masses and radii of the SuperWASP stars in good agreement with isochrone analysis results. We ascertain that the mass calibration is robust against uncertainties resulting from poor photometry, although a good estimate of stellar radius requires good-quality transit light curve to determine the duration of ingress and egress.Comment: 5 pages, 2 figures, accepted for publication in A&

    WASP-1: A lithium- and metal-rich star with an oversized planet

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    In this paper we present our results of a comprehensive spectroscopicanalysis of WASP-1, the host star to the exoplanet WASP-1b. We derive T_eff = 6110 +/- 45 K, log g = 4.28 +/- 0.15, and [M/H] = 0.23 +/- 0.08, and also a high abundance of lithium, log n(Li) = 2.91 +/- 0.05. These parameters suggests an age for the system of 1-3 Gyr and a stellar mass of 1.25-1.35 M_sun. This means that WASP-1 has properties very similar to those of HD 149026, the host star for the highest density planet yet detected. Moreover, their planets orbit at comparable distances and receive comparable irradiating fluxes from their host stars. However, despite the similarity of WASP-1 with HD 149026, their planets have strongly different densities. This suggests that gas-giant planet density is not a simple function of host-star metallicity or of radiation environment at ages of ~2 Gyr.Comment: Accepted for publication in MNRAS. 6 pages, 4 figure

    Detecting Differential Rotation and Starspot Evolution on the M dwarf GJ 1243 with Kepler

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    We present an analysis of the starspots on the active M4 dwarf GJ 1243, using four years of time series photometry from Kepler. A rapid P=0.592596±0.00021P = 0.592596\pm0.00021 day rotation period is measured due to the \sim2.2\% starspot-induced flux modulations in the light curve. We first use a light curve modeling approach, using a Monte Carlo Markov Chain sampler to solve for the longitudes and radii of the two spots within 5-day windows of data. Within each window of time the starspots are assumed to be unchanging. Only a weak constraint on the starspot latitudes can be implied from our modeling. The primary spot is found to be very stable over many years. A secondary spot feature is present in three portions of the light curve, decays on 100-500 day timescales, and moves in longitude over time. We interpret this longitude shearing as the signature of differential rotation. Using our models we measure an average shear between the starspots of 0.0047 rad day1^{-1}, which corresponds to a differential rotation rate of ΔΩ=0.012±0.002\Delta\Omega = 0.012 \pm 0.002 rad day1^{-1}. We also fit this starspot phase evolution using a series of bivariate Gaussian functions, which provides a consistent shear measurement. This is among the slowest differential rotation shear measurements yet measured for a star in this temperature regime, and provides an important constraint for dynamo models of low mass stars.Comment: 13 pages, 7 figures, ApJ Accepte
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