5,610 research outputs found

    Strategies For Covering the Uninsured: How California Policymakers Could Build on Lessons Learned at the Federal Level

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    Outlines possible health insurance coverage expansions in California that build on specific approaches from recent federal efforts

    Stochastic determination of matrix determinants

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    Matrix determinants play an important role in data analysis, in particular when Gaussian processes are involved. Due to currently exploding data volumes, linear operations - matrices - acting on the data are often not accessible directly but are only represented indirectly in form of a computer routine. Such a routine implements the transformation a data vector undergoes under matrix multiplication. While efficient probing routines to estimate a matrix's diagonal or trace, based solely on such computationally affordable matrix-vector multiplications, are well known and frequently used in signal inference, there is no stochastic estimate for its determinant. We introduce a probing method for the logarithm of a determinant of a linear operator. Our method rests upon a reformulation of the log-determinant by an integral representation and the transformation of the involved terms into stochastic expressions. This stochastic determinant determination enables large-size applications in Bayesian inference, in particular evidence calculations, model comparison, and posterior determination.Comment: 8 pages, 5 figure

    Early Implementation of the Health Coverage Tax Credit in Maryland, Michigan, and North Carolina: A Case Study Summary

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    Examines the effectiveness of HCTCs and assesses their prospects as a model for broader reforms. Proposes reforms to improve HCTCs' ability to help current target populations and aid policymakers in designing future health insurance tax credits

    Diagnostics for insufficiencies of posterior calculations in Bayesian signal inference

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    We present an error-diagnostic validation method for posterior distributions in Bayesian signal inference, an advancement of a previous work. It transfers deviations from the correct posterior into characteristic deviations from a uniform distribution of a quantity constructed for this purpose. We show that this method is able to reveal and discriminate several kinds of numerical and approximation errors, as well as their impact on the posterior distribution. For this we present four typical analytical examples of posteriors with incorrect variance, skewness, position of the maximum, or normalization. We show further how this test can be applied to multidimensional signals

    Phase diagram and phonon-induced backscattering in topological insulator nanowires

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    We present an effective low-energy theory of electron-phonon coupling effects for clean cylindrical topological insulator nanowires. Acoustic phonons are modelled by isotropic elastic continuum theory with stress-free boundary conditions. We take into account the deformation potential coupling between phonons and helical surface Dirac fermions, and also include electron-electron interactions within the bosonization approach. For half-integer values of the magnetic flux ΦB\Phi_B along the wire, the low-energy theory admits an exact solution since a topological protection mechanism then rules out phonon-induced 2kF2k_F-backscattering processes. We determine the zero-temperature phase diagram and identify a regime dominated by superconducting pairing of surface states. As example, we consider the phase diagram of HgTe nanowires. We also determine the phonon-induced electrical resistivity, where we find a quadratic dependence on the flux deviation δΦB\delta\Phi_B from the nearest half-integer value

    Federal Subsidy for Laid-Off Workers' Health Insurance: A First Year's Report Card for the New COBRA Premium Assistance

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    Analyzes how the subsidy for laid-off workers' costs to continue their health coverage, included in the 2009 stimulus bill, affected enrollment. Considers determining factors, implications of health reform for extending the subsidy, and lessons learned

    COBRA Subsidies for Laid-Off Workers: An Initial Report Card

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    Reviews the implementation of the government subsidy of COBRA health insurance premiums for laid-off workers in the 2009 stimulus package and its effects on COBRA enrollment and medical spending. Considers policy implications for access and affordability

    Teaching hate in the name of good

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    Hate groups are often portrayed as the province of men. Yet wives have not only supported their husbands in these groups, they have had their own organizations. These groups proclaim that their goal is not the propagation of hate, but some higher purpose, such as protecting America from that which is un-American. The United Daughters of the Confederacy (UDC) sought to preserve the memory of the Confederacy, through memorials, parades, and the teaching of catechisms to the children ensuring that the right history was conveyed. Among many things, the children were taught to hate Northerners. Later during the 1920s, many of the UDC joined the newly formed Women of the Ku Klux Klan (WKKK.) This paper will examine why normal, educated white women joined first the UDC then the WKKK, becoming spreaders of hate in the name of good. The major sources will be the primary sources, the publications of the UDC and WKKK, as well as the newspapers of the KKK. The significant secondary sources for the UDC are Karen Cox, Dixie\u27s Daughter: the United Daughters of the Confederacy and the Preservation of Confederate Culture; Drew Faust, This Republic of Suffering: Death and the American Civil War, and Charles Wilson, Baptized in Blood: the Religion of the Lost Cause, 1865-1920. For the WKKK, Kathleen Blee, Women of the Ku Klux Klan: Racism and Gender in the 1920s; Arnold Rice, The Ku Klux Klan in American Politics, and Wyn Wade, The Fiery Cross: the Ku Klux Klan in America. Common elements among the women in both groups: no regret or shame in having belonged, along with the ability to dissemble over their complicity in the on-going lashings, lynchings, arson and the ruining of businesses and reputations. They believed their organizations were performing a public good, that they were showing their patriotism as well as defending morality and God\u27s divine law of natural order. Hate can be addictive, especially when it is nurtured by family, friends and associates. For both the UDC and WKKK, the end justified the means

    Fast and precise way to calculate the posterior for the local non-Gaussianity parameter fnlf_\text{nl} from cosmic microwave background observations

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    We present an approximate calculation of the full Bayesian posterior probability distribution for the local non-Gaussianity parameter fnlf_{\text{nl}} from observations of cosmic microwave background anisotropies within the framework of information field theory. The approximation that we introduce allows us to dispense with numerically expensive sampling techniques. We use a novel posterior validation method (DIP test) in cosmology to test the precision of our method. It transfers inaccuracies of the calculated posterior into deviations from a uniform distribution for a specially constructed test quantity. For this procedure we study toy cases that use one- and two-dimensional flat skies, as well as the full spherical sky. We find that we are able to calculate the posterior precisely under a flat-sky approximation, albeit not in the spherical case. We argue that this is most likely due to an insufficient precision of the used numerical implementation of the spherical harmonic transform, which might affect other non-Gaussianity estimators as well. Furthermore, we present how a nonlinear reconstruction of the primordial gravitational potential on the full spherical sky can be obtained in principle. Using the flat-sky approximation, we find deviations for the posterior of fnlf_{\text{nl}} from a Gaussian shape that become more significant for larger values of the underlying true fnlf_{\text{nl}}. We also perform a comparison to the well-known estimator of Komatsu et al. [Astrophys. J. 634, 14 (2005)] and finally derive the posterior for the local non-Gaussianity parameter gnlg_{\text{nl}} as an example of how to extend the introduced formalism to higher orders of non-Gaussianity
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