1,288 research outputs found

    The Importance of State Anti-Discrimination Laws on Employer Accommodation and the Movement of their Employees onto Social Security Disability Insurance

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    The rate of application for Social Security Disability Insurance (SSDI) benefits, as well as the number of beneficiaries has been increasing for the past several decades, threatening the solvency of the SSDI program. One possible remedy is to promote continued employment amongst those experiencing the onset of a work limiting disability through the provision of workplace accommodations. Using the Health and Retirement Study data linked to Social Security administrative records and a state fixed effects model, we find that the provision of workplace accommodation reduces the probability of application for SSDI following disability onset. We estimate that receipt of an accommodation reduces a worker’s probability of applying for SSDI by 30 percent over five years and 21 percent over 10 years. We then attempt to control for the potential endogeneity of accommodation receipt by exploiting exogenous variation in the implementation of state and federal anti-discrimination laws to estimate the impact of workplace accommodation on SSDI application in an instrumental variables (IV) model. While our coefficients continue to indicate that accommodation reduces SSDI application, we obtain implausibly large estimates of this effect. Overall our results imply that increasing accommodation is a plausible strategy for reducing SSDI applications and the number of beneficiaries.Social Security Administrationhttp://deepblue.lib.umich.edu/bitstream/2027.42/87957/1/wp251.pd

    Parallel computation of radio listening rates

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    Obtaining the listening rates of radio stations in function of time is an important instrument for determining the impact of publicity. Since many radio stations are financed by publicity, the exact determination of radio listening rates is vital to their existence and to further development. Existing methods of determining radio listening rates are based on face to face interviews or telephonic interviews made with a sample population. These traditional methods however require the cooperation and compliance of the participants. In order to significantly improve the determination of radio listening rates, special watches were created which incorporate a custom integrated circuit sampling the ambient sound during a few seconds every minutes. Each watch accumulates these compressed sound samples during one full week. Watches are then sent to an evaluation center, where the sound samples are matched with the sound samples recorded from candidate radio stations. The present paper describes the processing steps necessary for computing the radio listening rates, and shows how this application was parallelized on a cluster of PCs using the CAP Computer-aided parallelization framework. Since the application must run in a production environment, the paper describes also the support provided for graceful degradation in case of transient or permanent failure of one of the system's components. The parallel sound matching server offers a linear speedup up to a large number of processing nodes thanks to the fact that disk access operations across the network are done in pipeline with computations

    On the lowest eigenvalue of Laplace operators with mixed boundary conditions

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    In this paper we consider a Robin-type Laplace operator on bounded domains. We study the dependence of its lowest eigenvalue on the boundary conditions and its asymptotic behavior in shrinking and expanding domains. For convex domains we establish two-sided estimates on the lowest eigenvalues in terms of the inradius and of the boundary conditions

    A natural Finsler--Laplace operator

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    We give a new definition of a Laplace operator for Finsler metric as an average with regard to an angle measure of the second directional derivatives. This definition uses a dynamical approach due to Foulon that does not require the use of connections nor local coordinates. We show using 1-parameter families of Katok--Ziller metrics that this Finsler--Laplace operator admits explicit representations and computations of spectral data.Comment: 25 pages, v2: minor modifications, changed the introductio

    Observation of diffractive orbits in the spectrum of excited NO in a magnetic field

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    We investigate the experimental spectra of excited NO molecules in the diamagnetic regime and develop a quantitative semiclassical framework to account for the results. We show the dynamics can be interpreted in terms of classical orbits provided that in addition to the geometric orbits, diffractive effects are appropriately taken into account. We also show how individual orbits can be extracted from the experimental signal and use this procedure to reveal the first experimental manifestation of inelastic diffractive orbits.Comment: 4 fig

    Scattering Theory of Kondo Mirages and Observation of Single Kondo Atom Phase Shift

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    We explain the origin of the Kondo mirage seen in recent quantum corral Scanning Tunneling Microscope (STM) experiments with a scattering theory of electrons on the surfaces of metals. Our theory combined with experimental data provides the first direct observation of a single Kondo atom phase shift. The Kondo mirage at the empty focus of an elliptical quantum corral is shown to arise from multiple electron bounces off the walls of the corral in a manner analagous to the formation of a real image in optics. We demonstrate our theory with direct quantitive comparision to experimental data.Comment: 13 pages; significant clarifications of metho

    Diffraction and boundary conditions in semi-classical open billiards

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    The conductance through open quantum dots or quantum billiards shows fluctuations, that can be explained as interference between waves following different paths between the leads of the billiard. We examine such systems by the use of a semi-classical Green's functions. In this paper we examine how the choice of boundary conditions at the lead mouths affect the diffraction. We derive a new formula for the S-matrix element. Finally we compare semi-classical simulations to quantum mechanical ones, and show that this new formula yield superior results.Comment: 7 pages, 4 figure
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