91 research outputs found
Creating the Canada/Quebec Pension Plans: An Historical and Political Analysis
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
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
Thomson scattering of the cosmic microwave background (CMB) on moving electrons in the outflows of Lyman break galaxies (LBGs) at redshifts 2â8 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
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
of in the Ka, Q, V and W bands
respectively. The level of bias we find is largely insufficient to explain the
very high values recently detected by Yadav and Wandelt. For Planck,
we estimate the point source bispectra to contaminate the estimator
with a bias of at
respectively. These results depend on the assumed redshift distribution of the
point sources. However, given the projected Planck sensitivity of (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
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
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
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
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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