53,074 research outputs found
Election results and opportunistic policies: A new test of the rational political business cycle model
The literature on the rational political business cycle suggests that politicians systematically manipulate economic and fiscal conditions before elections to increase their chance of gaining reelection. Most tests of this theory look for evidence of pre-
election distortions in fiscal policy. We propose a new test that, instead, explores the implied two-way interaction between the magnitude of the opportunistic distortion and the margin of victory. The test is implemented using a panel of 278 Portuguese
municipalities (from 1979 to 2005). The results show that (1) opportunism pays off, leading to a larger win-margin for the incumbent; (2) incumbents behave more opportunistically when their win-margin is small. These results are consistent with the theoretical model
Recovery from Linear Measurements with Complexity-Matching Universal Signal Estimation
We study the compressed sensing (CS) signal estimation problem where an input
signal is measured via a linear matrix multiplication under additive noise.
While this setup usually assumes sparsity or compressibility in the input
signal during recovery, the signal structure that can be leveraged is often not
known a priori. In this paper, we consider universal CS recovery, where the
statistics of a stationary ergodic signal source are estimated simultaneously
with the signal itself. Inspired by Kolmogorov complexity and minimum
description length, we focus on a maximum a posteriori (MAP) estimation
framework that leverages universal priors to match the complexity of the
source. Our framework can also be applied to general linear inverse problems
where more measurements than in CS might be needed. We provide theoretical
results that support the algorithmic feasibility of universal MAP estimation
using a Markov chain Monte Carlo implementation, which is computationally
challenging. We incorporate some techniques to accelerate the algorithm while
providing comparable and in many cases better reconstruction quality than
existing algorithms. Experimental results show the promise of universality in
CS, particularly for low-complexity sources that do not exhibit standard
sparsity or compressibility.Comment: 29 pages, 8 figure
Correcting for Distortions due to Ionization in the STAR TPC
Physics goals of the STAR Experiment at RHIC in recent (and future) years
drive the need to operate the STAR TPC at ever higher luminosities, leading to
increased ionization levels in the TPC gas. The resulting ionic space charge
introduces field distortions in the detector which impact tracking performance.
Further complications arise from ionic charge leakage into the main TPC volume
from the high gain anode region. STAR has implemented corrections for these
distortions based on measures of luminosity, which we present here.
Additionally, we highlight a novel approach to applying the corrections on an
event-by-event basis applicable in conditions of rapidly varying ionization
sources.Comment: 6 pages, 7 figures, proceedings of the Workshop on Tracking in High
Multiplicity Environments (TIME 05) in Zurich, Switzerland, submitted to
Nucl. Instr. and Meth.
A practical guide and software for analysing pairwise comparison experiments
Most popular strategies to capture subjective judgments from humans involve
the construction of a unidimensional relative measurement scale, representing
order preferences or judgments about a set of objects or conditions. This
information is generally captured by means of direct scoring, either in the
form of a Likert or cardinal scale, or by comparative judgments in pairs or
sets. In this sense, the use of pairwise comparisons is becoming increasingly
popular because of the simplicity of this experimental procedure. However, this
strategy requires non-trivial data analysis to aggregate the comparison ranks
into a quality scale and analyse the results, in order to take full advantage
of the collected data. This paper explains the process of translating pairwise
comparison data into a measurement scale, discusses the benefits and
limitations of such scaling methods and introduces a publicly available
software in Matlab. We improve on existing scaling methods by introducing
outlier analysis, providing methods for computing confidence intervals and
statistical testing and introducing a prior, which reduces estimation error
when the number of observers is low. Most of our examples focus on image
quality assessment.Comment: Code available at https://github.com/mantiuk/pwcm
First Weak-lensing Results from "See Change": Quantifying Dark Matter in the Two Z>1.5 High-redshift Galaxy Clusters SPT-CL J2040-4451 and IDCS J1426+3508
We present a weak-lensing study of SPT-CLJ2040-4451 and IDCSJ1426+3508 at
z=1.48 and 1.75, respectively. The two clusters were observed in our "See
Change" program, a HST survey of 12 massive high-redshift clusters aimed at
high-z supernova measurements and weak-lensing estimation of accurate cluster
masses. We detect weak but significant galaxy shape distortions using IR images
from the WFC3, which has not yet been used for weak-lensing studies. Both
clusters appear to possess relaxed morphology in projected mass distribution,
and their mass centroids agree nicely with those defined by both the galaxy
luminosity and X-ray emission. Using an NFW profile, for which we assume that
the mass is tightly correlated with the concentration parameter, we determine
the masses of SPT-CL J2040-4451 and IDCS J1426+3508 to be
M_{200}=8.6_{-1.4}^{+1.7}x10^14 M_sun and 2.2_{-0.7}^{+1.1}x10^14 M_sun,
respectively. The weak-lensing mass of SPT-CLJ2040-4451 shows that the cluster
is clearly a rare object. Adopting the central value, the expected abundance of
such a massive cluster at z>1.48 is only ~0.07 in the parent 2500 sq. deg.
survey. However, it is yet premature to claim that the presence of this cluster
creates a serious tension with the current LCDM paradigm unless that tension
will remain in future studies after marginalizing over many sources of
uncertainties such as the accuracy of the mass function and the
mass-concentration relation at the high mass end. The mass of IDCSJ1426+3508 is
in excellent agreement with our previous ACS-based weak-lensing result while
the much higher source density from our WFC3 imaging data makes the current
statistical uncertainty ~40% smaller.Comment: Accepted to Ap
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