1,754,953 research outputs found
The Power of Weak Interests in Financial Reforms:Explaining the Creation of a US Consumer Agency
Dodd-Frank, the US financial reform law passed in response to the 2008 financial crisis, established
the Consumer Financial Protection Bureau (CFPB), a new federal regulator with
the sole responsibility of protecting consumers from unfair, deceptive, or abusive practices.
This decision marked the end of a highly politicized reform debate in the US Congress,
involving lobbying from business associations and civil society groups, in which proponents
of the new bureau would normally have been considered to be much weaker than its
opponents. Paradoxically, an emerging civil society coalition successfully lobbied decisionmakers
and countered industry attempts to prevent industry capture. What explains the
fact that rather weak and peripheral actors prevailed over more resourceful and dominant
actors? The goal of this study is to examine and challenge questions of regulatory capture by
concentrated industry interests in the reform debates in response to the credit crisis which
originated in the US in 2007. The analysis suggests that for weak actors to prevail in policy
conflicts over established, resource-rich opponents, they must undertake broad coalitionbuilding
among themselves and with influential elite allies outside and inside of Congress
who share the same policy goals
Trade Implies Law: The Power of the Weak
Without the rule of law, traders who incur trading costs can be held up by counter-parties who are stronger in anarchic bargaining. The favourable terms which the latter extract can overcrowd that side of the market, dissipating the benefits. We establish plausible necessary and sufficient conditions for a move from anarchy toward the rule of law to benefit all traders. The rule of law might be delayed, not only by the difficulties of setting up legal institutions, but by monopolistic traders that have meantime emerged to address the inefficiencies of anarchic trade. These monopolistic traders must also guarantee atomistic traders against holdup.
The Power of the Weak
A landmark result in the study of logics for formal verification is Janin and Walukiewicz’s theorem, stating that the modal μ-calculus (μML) is equivalent modulo bisimilarity to standard monadic second-order logic (here abbreviated as SMSO) over the class of labelled transition systems (LTSs for short). Our work proves two results of the same kind, one for the alternation-free or noetherian fragment μNML of μML on the modal side and one for WMSO, weak monadic second-order logic, on the second-order side. In the setting of binary trees, with explicit functions accessing the left and right successor of a node, it was known that WMSO is equivalent to the appropriate version of alternation-free μ-calculus. Our analysis shows that the picture changes radically once we consider, as Janin and Walukiewicz did, the standard modal μ-calculus, interpreted over arbitrary LTSs.
The first theorem that we prove is that, over LTSs, μNML is equivalent modulo bisimilarity to noetherian MSO (NMSO), a newly introduced variant of SMSO where second-order quantification ranges over “conversely well-founded” subsets only. Our second theorem starts from WMSO and proves it equivalent modulo bisimilarity to a fragment of μNML defined by a notion of continuity. Analogously to Janin and Walukiewicz’s result, our proofs are automata-theoretic in nature: As another contribution, we introduce classes of parity automata characterising the expressiveness of WMSO and NMSO (on tree models) and of μCML and μNML (for all transition systems)
Effect of Hot Baryons on the Weak-Lensing Shear Power Spectrum
We investigate the impact of the intracluster medium on the weak-lensing
shear power spectrum (PS). Using a halo model we find that, compared to the
dark matter only case, baryonic pressure leads to a suppression of the shear PS
on the order of a few percent or more for . Cooling/cooled
baryons and the intergalactic medium can further alter the shear PS. Therefore,
the interpretation of future precision weak lensing data at high multipoles
must take into account the effects of baryons.Comment: 4 pages, 3 figure
Optimal capture of non-Gaussianity in weak lensing surveys: power spectrum, bispectrum and halo counts
We compare the efficiency of weak lensing-selected galaxy clusters counts and
of the weak lensing bispectrum at capturing non-Gaussian features in the dark
matter distribution. We use the halo model to compute the weak lensing power
spectrum, the bispectrum and the expected number of detected clusters, and
derive constraints on cosmological parameters for a large, low systematic weak
lensing survey, by focusing on the - plane and on the dark
energy equation of state. We separate the power spectrum into the resolved and
the unresolved parts of the data, the resolved part being defined as detected
clusters, and the unresolved part as the rest of the field. We consider four
kinds of clusters counts, taking into account different amount of information :
signal-to-noise ratio peak counts; counts as a function of clusters' mass;
counts as a function of clusters' redshift; and counts as a function of
clusters' mass and redshift. We show that when combined with the power
spectrum, those four kinds of counts provide similar constraints, thus allowing
one to perform the most direct counts, signal-to-noise peaks counts, and get
percent level constraints on cosmological parameters. We show that the weak
lensing bispectrum gives constraints comparable to those given by the power
spectrum and captures non-Gaussian features as well as clusters counts, its
combination with the power spectrum giving errors on cosmological parameters
that are similar to, if not marginally smaller than, those obtained when
combining the power spectrum with cluster counts. We finally note that in order
to reach its potential, the weak lensing bispectrum must be computed using all
triangle configurations, as equilateral triangles alone do not provide useful
information.Comment: Matches ApJ-accepted versio
Fitting formulae of the reduced-shear power spectrum for weak lensing
Context. Weak gravitational lensing is a powerful probe of large-scale
structure and cosmology. Most commonly, second-order correlations of observed
galaxy ellipticities are expressed as a projection of the matter power
spectrum, corresponding to the lowest-order approximation between the projected
and 3d power spectrum.
Aims. The dominant lensing-only contribution beyond the zero-order
approximation is the reduced shear, which takes into account not only
lensing-induced distortions but also isotropic magnification of galaxy images.
This involves an integral over the matter bispectrum. We provide a fast and
general way to calculate this correction term.
Methods. Using a model for the matter bispectrum, we fit elementary functions
to the reduced-shear contribution and its derivatives with respect to
cosmological parameters. The dependence on cosmology is encompassed in a
Taylor-expansion around a fiducial model.
Results. Within a region in parameter space comprising the WMAP7 68% error
ellipsoid, the total reduced-shear power spectrum (shear plus fitted
reduced-shear correction) is accurate to 1% (2%) for l<10^4 (l<2x10^5). This
corresponds to a factor of four reduction of the bias compared to the case
where no correction is used. This precision is necessary to match the accuracy
of current non-linear power spectrum predictions from numerical simulations.Comment: 7 pages, 3 figures. A&A in press. Revised version with minor change
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