91 research outputs found

    Creating the Canada/Quebec Pension Plans: An Historical and Political Analysis

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    Drawing on recent historical institutionalist scholarship, this paper explores the debates leading to the enactment of the Canada/Quebec Pension Plans (C/Q.P.P.) in 1965. More specifically, this analysis underlines the respective role of and the interaction between political institutions, business and labor power, and changing ideas about the role of public and private pensions in Canada. As argued, although the ideas that guided the enactment of C/Q.P.P. stressed the key role of private benefits, the enduring weight of Canadian-style federalism mitigated the impact of interest groups, especially business organizations, on the legislative process. Overall, the paper suggests that students of social policy should pay closer attention to the interaction between political institutions, interest group mobilization, and changing ideas about the relationship between public and private benefits.pensions, ideas, institutions, federalism, politics, social policy, business, labor, private benefits, Canada

    Primordial Bispectrum Information from CMB Polarization

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    After the precise observations of the Cosmic Microwave Background (CMB) anisotropy power spectrum, attention is now being focused on the higher order statistics of the CMB anisotropies. Since linear evolution preserves the statistical properties of the initial conditions, observed non-Gaussianity of the CMB will mirror primordial non-Gaussianity. Single field slow-roll inflation robustly predicts negligible non-Gaussianity so an indication of non-Gaussianity will suggest alternative scenarios need to be considered. In this paper we calculate the information on primordial non-Gaussianity encoded in the polarization of the CMB. After deriving the optimal weights for a cubic estimator we evaluate the Signal-to-Noise ratio of the estimator for WMAP, Planck and an ideal cosmic variance limited experiment. We find that when the experiment can observe CMB polarization with good sensitivity, the sensitivity to primordial non-Gaussianity increases by roughly a factor of two. We also test the weakly non-Gaussian assumption used to derive the optimal weight factor by calculating the degradation factor produced by the gravitational lensing induced connected four-point function. The physical scales in the radiative transfer functions are largely irrelevant for the constraints on the primordial non-Gaussianity. We show that the total (S/N)^2 is simply proportional to the number of observed pixels on the sky.Comment: To be submitted to PRD, 25 pages, 6 figure

    Cosmic microwave background anisotropies from outflows in Lyman break galaxies

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    Thomson scattering of the cosmic microwave background (CMB) on moving electrons in the outflows of Lyman break galaxies (LBGs) at redshifts 2–8 contributes to the small-scale CMB anisotropies. The net effect produced by each outflow depends on its level of deviation from spherical symmetry, caused either by an anisotropic energy injection from the nuclear starburst or quasar activity, or by an inhomogeneous intergalactic environment. We find that for plausible outflow parameters consistent with spectroscopic observations of LBGs, the induced CMB anisotropies on arcminute scales reach up to ~1 ÎŒK, comparable to the level produced during the epoch of reionization

    Point Source Contamination in CMB Non-Gaussianity Analyses

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    In this paper we analyze the biasing effect of point sources, either thermal Sunyaev-Zeldovich clusters or standard radio sources, on the estimated strength of the non-Gaussianity in the Cosmic Microwave Background (CMB). We show that the biggest contribution comes from the cross--correlation of the CMB with the matter density rather than from the poisson term which is conventionally assumed in these calculations. For the three year WMAP data, we estimate that point sources could produce a non--Gaussian signature equivalent to a bias in fNLf_{NL} of 0.35,0.24,−0.097,−0.130.35, 0.24, -0.097, -0.13 in the Ka, Q, V and W bands respectively. The level of bias we find is largely insufficient to explain the very high fNLf_{NL} values recently detected by Yadav and Wandelt. For Planck, we estimate the point source bispectra to contaminate the fNLf_{NL} estimator with a bias of 1.3,0.34,−0.25,−0.481.3, 0.34, -0.25, -0.48 at 30,44,70,100GHz30, 44, 70, 100 {\rm GHz} respectively. These results depend on the assumed redshift distribution of the point sources. However, given the projected Planck sensitivity of ΔfNL≃5\Delta f_{NL} \simeq 5 (95 % C.L.), a good estimate of point sources' properties including their number density and redshift distribution is essential before deriving strong conclusions on primordial non--Gaussianity.Comment: 15 pages, 7 figures. To be submitted to PR

    Imprint of Inhomogeneous Reionization on the Power Spectrum of Galaxy Surveys at High Redshifts

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    We consider the effects of inhomogeneous reionization on the distribution of galaxies at high redshifts. Modulation of the formation process of the ionizing sources by large scale density modes makes reionization inhomogeneous and introduces a spread to the reionization times of different regions with the same size. After sources photo-ionize and heat these regions to a temperature \ga 10^4K at different times, their temperatures evolve as the ionized intergalactic medium (IGM) expands. The varying IGM temperature makes the minimum mass of galaxies spatially non-uniform with a fluctuation amplitude that increases towards small scales. These scale-dependent fluctuations modify the shape of the power spectrum of low-mass galaxies at high redshifts in a way that depends on the history of reionization. The resulting distortion of the primordial power spectrum is significantly larger than changes associated with uncertainties in the inflationary parameters, such as the spectral index of the scalar power spectrum or the running of the spectral index. Future surveys of high-redshift galaxies will offer a new probe of the thermal history of the IGM but might have a more limited scope in constraining inflation.Comment: 8 pages, 5 figures, replaced to match version accepted by Ap

    Regular modes in rotating stars

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    Despite more and more observational data, stellar acoustic oscillation modes are not well understood as soon as rotation cannot be treated perturbatively. In a way similar to semiclassical theory in quantum physics, we use acoustic ray dynamics to build an asymptotic theory for the subset of regular modes which are the easiest to observe and identify. Comparisons with 2D numerical simulations of oscillations in polytropic stars show that both the frequency and amplitude distributions of these modes can accurately be described by an asymptotic theory for almost all rotation rates. The spectra are mainly characterized by two quantum numbers; their extraction from observed spectra should enable one to obtain information about stellar interiors.Comment: 5 pages, 4 figures, discussion adde

    Oscillations in the bispectrum

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    There exist several models of inflation that produce primordial bispectra that contain a large number of oscillations. In this paper we discuss these models, and aim at finding a method of detecting such bispectra in the data. We explain how the recently proposed method of mode expansion of bispectra might be able to reconstruct these spectra from separable basis functions. Extracting these basis functions from the data might then lead to observational constraints on these models.Comment: 6 pages, 2 figures, submitted to JOP: Conference Series, PASCOS 201

    Extraction of Spin-Dependent Parton Densities and Their Uncertainties

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    We discuss techniques and results for the extraction of the nucleon's spin-dependent parton distributions and their uncertainties from data for polarized deep-inelastic lepton-nucleon and proton-proton scattering by means of a global QCD analysis. Computational methods are described that significantly increase the speed of the required calculations to a level that allows to perform the full analysis consistently at next-to-leading order accuracy. We examine how the various data sets help to constrain different aspects of the quark, anti-quark, and gluon helicity distributions. Uncertainty estimates are performed using both the Lagrange multiplier and the Hessian approaches. We use the extracted parton distribution functions and their estimated uncertainties to predict spin asymmetries for high-transverse momentum pion and jet production in polarized proton-proton collisions at 500 GeV center-of-mass system energy at BNL-RHIC, as well as for W boson production.Comment: 25 pages, 15 eps figures, v2: minor changes, final version to appear in Phys. Rev.
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