1,721 research outputs found
Panel Cointegration and the Monetary Exchange Rate Model
This paper re-examines the validity of the monetary exchange rate model during the post-Bretton Woods era for 18 OECD countries. Our analysis simultaneously considers the presence of both cross-sectional dependence and multiple structural breaks, which have not received much attention in previous studies of the monetary model. The empirical results indicate that the monetary model emerges only when the presence of structural breaks and cross-country dependence has been taken into account. Evidence is also provided suggesting that the breaks in the monetary model can be derived from the underlying purchasing power parity relation.
Can Panel Data Really Improve the Predictability of the Monetary Exchange Rate Model?
A common explanation for the inability of the monetary model to beat the random walk in forecasting future exchange rates is that conventional time series tests may have low power, and that panel data should generate more powerful tests. This paper provides an extensive evaluation of this power argument to the use of panel data in the forecasting context. In particular, by using simulations it is shown that although pooling of the individual prediction tests can lead to substantial power gains, pooling only the parameters of the forecasting equation, as has been suggested in the previous literature, does not seem to generate more powerful tests. The simulation results are illustrated through an empirical application.Monetary Exchange Rate Model; Forecasting; Panel Data; Pooling; Bootstrap
Is there Really a Unit Root in the Inflation Rate? More Evidence from Panel Data Models
Time series unit root evidence suggests that inflation is nonstationary. By contrast, when using more powerful panel unit root tests, Culver and Papell (1997) find that inflation is stationary. In this paper, we test the robustness of this result by applying a battery of recent panel unit root tests. The results suggest that the stationarity of inflation holds even after controlling for crosssectional dependence and structural change.Unit Root; Inflation; Cross-Sectional Dependence; Structural Change
Mixed Signals Among Tests for Panel Cointegration
In this paper, we study the effect that different serial correlation adjustment methods can have on panel cointegration testing. As an example, we consider the very popular tests developed by Pedroni (1999, 2004). Results based on both simulated and real data suggest that different adjustment methods can lead to significant variations in test outcome, and thus also in the conclusions.Panel Data; Cointegration Testing; Parametric and Semiparametric Methods
Testing for Convergence in Carbon Dioxide Emissions Using a Century of Panel Data
This paper tests the convergence in per-capita carbon dioxide emissions for a collection of developed and developing countries using data spanning the period 1870 to 2002. For this purpose, three recently developed panel unit root tests that permit for dependence among the individual countries are employed. The results lend strong support in favor of convergence for the panel as a whole. Estimates of the speed of this convergence is also provided.Emissions convergence; Panel unit root tests; Common factors; Half-life
The positron excess and supersymmetric dark matter
Using a new instrument, the HEAT collaboration has confirmed the excess of
cosmic ray positrons that they first detected in 1994. We explore the
possibility that this excess is due to the annihilation of neutralino dark
matter in the galactic halo. We confirm that neutralino annihilation can
produce enough positrons to make up the measured excess only if there is an
additional enhancement to the signal. We quantify the `boost factor' that is
required in the signal for various models in the Minimal Supersymmetric
Standard Model parameter space, and find that a boost factor >30 provides good
fits to the HEAT data. Such an enhancement in the signal could arise if we live
in a clumpy halo.Comment: 6 pages, LaTeX, proceedings of the 4th International Workshop on
Identification of Dark Matter (idm2002), York, England, 2-6 September, 200
Curvature and geometric modules of noncommutative spheres and tori
When considered as submanifolds of Euclidean space, the Riemannian geometry
of the round sphere and the Clifford torus may be formulated in terms of
Poisson algebraic expressions involving the embedding coordinates, and a
central object is the projection operator, projecting tangent vectors in the
ambient space onto the tangent space of the submanifold. In this note, we point
out that there exist noncommutative analogues of these projection operators,
which implies a very natural definition of noncommutative tangent spaces as
particular projective modules. These modules carry an induced connection from
Euclidean space, and we compute its scalar curvature
DarkSUSY - A numerical package for dark matter calculations in the MSSM
The question of the nature of the dark matter in the Universe remains one of
the most outstanding unsolved problems in basic science. One of the best
motivated particle physics candidates is the lightest supersymmetric particle,
assumed to be the lightest neutralino. We here describe DarkSUSY, an advanced
numerical FORTRAN package for supersymmetric dark matter calculations which we
release for public use. With the help of this package, the masses and
compositions of various supersymmetric particles can be computed, for given
input parameters of the minimal supersymmetric extension of the Standard Model
(MSSM). For the lightest neutralino, the relic density is computed, using
accurate methods which include the effects of resonances, pair production
thresholds and coannihilations. Accelerator bounds are checked to identify
viable dark matter candidates. Finally, detection rates are computed for a
variety of detection methods, such as direct detection and indirect detection
through antiprotons, gamma-rays and positrons from the Galactic halo or
neutrinos from the center of the Earth or the Sun.Comment: 6 pages, no figures. Contribution to the proceedings of the 3rd
International Workshop on the Identification of Dark Matter (IDM2000) in
York, in pres
Models of environment and T_1 relaxation in Josephson Charge Qubits
A theoretical interpretation of the recent experiments of Astafiev et. al. on
the T_1-relaxation rate in Josephson Charge Qubits is proposed. The
experimentally observed reproducible nonmonotonic dependence of T_1 on the
splitting E_J of the qubit levels suggests further specification of the
previously proposed models of the background charge noise. From our point of
view the most promising is the ``Andreev fluctuator'' model of the noise. In
this model the fluctuator is a Cooper pair that tunnels from a superconductor
and occupies a pair of localized electronic states. Within this model one can
naturally explain both the average linear T_1(E_J) dependence and the irregular
fluctuations. The role of fluctuators in the formation of strong resonant peaks
in this dependence is also discussed.Comment: 4 pages, 3 figure
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