31,603 research outputs found
Elections and the Timing of Devaluations
This paper presents a rational political budget cycle model for the open economy, in which devaluations are delayed in the run-up to elections, in order to increase the electoral chances of the party in office. By concentrating on the closed economy, previous political cycle models had overlooked the influence of elections on the behavior of exchange rates. We introduce voter uncertainty in two different dimensions. Not only are voters uncertain regarding the competency of the incumbent. They also ignore the degree to which the incumbent is opportunistic, i.e. willing to distort the economy for electoral gain. When there is only uncertainty about competence, we obtain a separating equilibrium, like in the previous political budget cycle literature. However, when uncertainty about opportunism is introduced, a partially pooling equilibrium emerges: an incompetent, opportunistic incumbent delays a devaluation until after elections, mimicking a competent incumbent, while the competent does not distort the optimal pattern of the exchange rate, regardless of the degree of opportunism. The model's prediction that there is a tendency to delay devaluations until after elections is used to look at the empirical evidence on devaluations around elections.devaluations, elections, political budget cycles, incomplete information.
Elections and the Timing of Devaluations
This paper presents a rational political budget cycle model for an open economy, in which devaluations are delayed in the pre-election period so as to increase the electoral chances of the party in office. By concentrating on closed economies, previous political cycle models had overlooked the influence of elections on the behavior of exchange rates. Voter uncertainty is introduced in two different dimensions. Not only are voters uncertain regarding the competency of the incumbent, but tey also ignore the degree to which the incumbent is opportunistic.
Radon gas, useful for medical purposes, safely fixed in quartz
Radon gas is enclosed in quartz or glass ampules by subjecting the gas sealed at a low pressure in the ampules to an ionization process. This process is useful for preparing fixed radon sources for radiological treatment of malignancies, without the danger of releasing radioactive gases
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A comparison among four different retrieval methods for ice-cloud properties using data from CloudSat, CALIPSO, and MODIS
The A-Train constellation of satellites provides a new capability to measure vertical cloud profiles that leads to more detailed information on ice-cloud microphysical properties than has been possible up to now. A variational radar–lidar ice-cloud retrieval algorithm (VarCloud) takes advantage of the complementary nature of the CloudSat radar and Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) lidar to provide a seamless retrieval of ice water content, effective radius, and extinction coefficient from the thinnest cirrus (seen only by the lidar) to the thickest ice cloud (penetrated only by the radar). In this paper, several versions of the VarCloud retrieval are compared with the CloudSat standard ice-only retrieval of ice water content, two empirical formulas that derive ice water content from radar reflectivity and temperature, and retrievals of vertically integrated properties from the Moderate Resolution Imaging Spectroradiometer (MODIS) radiometer. The retrieved variables typically agree to within a factor of 2, on average, and most of the differences can be explained by the different microphysical assumptions. For example, the ice water content comparison illustrates the sensitivity of the retrievals to assumed ice particle shape. If ice particles are modeled as oblate spheroids rather than spheres for radar scattering then the retrieved ice water content is reduced by on average 50% in clouds with a reflectivity factor larger than 0 dBZ. VarCloud retrieves optical depths that are on average a factor-of-2 lower than those from MODIS, which can be explained by the different assumptions on particle mass and area; if VarCloud mimics the MODIS assumptions then better agreement is found in effective radius and optical depth is overestimated. MODIS predicts the mean vertically integrated ice water content to be around a factor-of-3 lower than that from VarCloud for the same retrievals, however, because the MODIS algorithm assumes that its retrieved effective radius (which is mostly representative of cloud top) is constant throughout the depth of the cloud. These comparisons highlight the need to refine microphysical assumptions in all retrieval algorithms and also for future studies to compare not only the mean values but also the full probability density function
On the Fourier transform of the characteristic functions of domains with -smooth boundary
We consider domains with -smooth boundary and
study the following question: when the Fourier transform of the
characteristic function belongs to ?Comment: added two references; added footnotes on pages 6 and 1
The effects of numerical resolution on hydrodynamical surface convection simulations and spectral line formation
The computationally demanding nature of radiative-hydrodynamical simulations
of stellar surface convection warrants an investigation of the sensitivity of
the convective structure and spectral synthesis to the numerical resolution and
dimension of the simulations, which is presented here. With too coarse a
resolution the predicted spectral lines tend to be too narrow, reflecting
insufficient Doppler broadening from the convective motions, while at the
currently highest affordable resolution the line shapes have converged
essentially perfectly to the observed profiles. Similar conclusions are drawn
from the line asymmetries and shifts. In terms of abundances, weak FeI and FeII
lines show a very small dependence (~0.02 dex) while for intermediate strong
lines with significant non-thermal broadening the sensitivity increases (~0.10
dex). Problems arise when using 2D convection simulations to describe an
inherent 3D phenomenon, which translates to inaccurate atmospheric velocity
fields and temperature and pressure structures. In 2D the theoretical line
profiles tend to be too shallow and broad compared with the 3D calculations and
observations, in particular for intermediate strong lines. In terms of
abundances, the 2D results are systematically about 0.1 dex lower than for the
3D case for FeI lines. Furthermore, the predicted line asymmetries and shifts
are much inferior in 2D. Given these shortcomings and computing time
considerations it is better to use 3D simulations of even modest resolution
than high-resolution 2D simulations.Comment: Accepted for A&
STOP - A computer program for supersonic transport trajectory optimization
IBM 7094 digital program using steepest ascent technique for optimizing flight path of supersonic transport aircraf
Using rewards and penalties to obtain desired subject performance
Operant conditioning procedures, specifically the use of negative reinforcement, in achieving stable learning behavior is described. The critical tracking test (CTT) a method of detecting human operator impairment was tested. A pass level is set for each subject, based on that subject's asymptotic skill level while sober. It is critical that complete training take place before the individualized pass level is set in order that the impairment can be detected. The results provide a more general basis for the application of reward/penalty structures in manual control research
A simulation of solar convection at supergranulation scale
We present here numerical simulations of surface solar convection which cover
a box of 303.2 Mm with a resolution of
31582, which is used to investigate the dynamics of scales
larger than granulation. No structure resembling supergranulation is present;
possibly higher Reynolds numbers (i.e. higher numerical resolution), or
magnetic fields, or greater depth are necessary. The results also show
interesting aspects of granular dynamics which are briefly presented, like
extensive p-mode ridges in the k- diagram and a ringlike distribution
of horizontal vorticity around granules. At large scales, the horizontal
velocity is much larger than the vertical velocity and the vertical motion is
dominated by p-mode oscillations.Comment: Contribution to the proceedings of the workshop entitled "THEMIS and
the new frontiers of solar atmosphere dynamics" (March 2001), 6 pages, to
appear in Nuovo Cimento
Realistic Magnetohydrodynamical Simulation of Solar Local Supergranulation
Three-dimensional numerical simulations of solar surface magnetoconvection
using realistic model physics are conducted. The thermal structure of
convective motions into the upper radiative layers of the photosphere, the main
scales of convective cells and the penetration depths of convection are
investigated. We take part of the solar photosphere with size of 60x60 Mm in
horizontal direction and by depth 20 Mm from level of the visible solar
surface. We use a realistic initial model of the Sun and apply equation of
state and opacities of stellar matter. The equations of fully compressible
radiation magnetohydrodynamics with dynamical viscosity and gravity are solved.
We apply: 1) conservative TVD difference scheme for the magnetohydrodynamics,
2) the diffusion approximation for the radiative transfer, 3) dynamical
viscosity from subgrid scale modeling. In simulation we take uniform
two-dimesional grid in gorizontal plane and nonuniform grid in vertical
direction with number of cells 600x600x204. We use 512 processors with
distributed memory multiprocessors on supercomputer MVS-100k in the Joint
Computational Centre of the Russian Academy of Sciences.Comment: 6 pages, 5 figures, submitted to the proceedings of the GONG 2008 /
SOHO XXI conferenc
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