20,285 research outputs found
The Current Account and the Interest Differential In Canada
For post-1975 Canadian data, we document the joint behavior of output, the current account, and the interest differential at the business cycle frequency. We also interpret the joint behavior using a simple small open economy model. Our simple model assumes that agents have access to world international financial markets, but face country-specific interest rate on their holdings of world assets. The interest differential depends negatively on the country’s net foreign asset position. We find that our simple model matches the Canadian data remarkably well.International Real Business Cycle, Small Open Economy, Habit Formation.
Closing International Real Business Cycle Models with Restricted Financial Markets
Several authors argue that international real business cycle (IRBC) models with incomplete financial markets offer a good explanation of the ranking of cross-country correlations. Unfortunately, this conclusion is suspect, because it is commonly based on an analysis of the near steady state dynamics using a linearized system of equations. The baseline IRBC model with incomplete financial markets does not possess a unique deterministic steady state and, as a result, its linear system of difference equations is not stationary. We show that the explanation of the ranking of cross-country correlations is robust to modifications that ensure a unique steady state and a stationary system of linear difference equations. We find, however, that the modifications affect the quantitative predictions regarding key macroeconomic variables.Incomplete markets, stationarity, cross-country correlations, wealth effects.
Closing International Real Business Cycle Models with Restricted Financial Markets
Several authors argue that international real business cycle (IRBC) models with incomplete financial markets offer a good explanation of the ranking of cross-country correlations. Unfortunately, this conclusion is suspect, because it is commonly based on an analysis of the near steady state dynamics using a linearized system of equations. The baseline IRBC model with incomplete financial markets does not possess a unique deterministic steady state and, as a result, its linear system of difference equations is not stationary. We show that the explanation of the ranking of cross-country correlations is robust to modifications that ensure a unique steady state and a stationary system of linear difference equations. We find, however, that the modifications affect the quantitative predictions regarding key macroeconomic variables.Incomplete markets, stationarity, cross-country correlations, wealth effects
Spin and chiral stiffness of the XY spin glass in two dimensions
We analyze the zero-temperature behavior of the XY Edwards-Anderson spin
glass model on a square lattice. A newly developed algorithm combining exact
ground-state computations for Ising variables embedded into the planar spins
with a specially tailored evolutionary method, resulting in the genetic
embedded matching (GEM) approach, allows for the computation of numerically
exact ground states for relatively large systems. This enables a thorough
re-investigation of the long-standing questions of (i) extensive degeneracy of
the ground state and (ii) a possible decoupling of spin and chiral degrees of
freedom in such systems. The new algorithm together with appropriate choices
for the considered sets of boundary conditions and finite-size scaling
techniques allows for a consistent determination of the spin and chiral
stiffness scaling exponents.Comment: 6 pages, 2 figures, proceedings of the HFM2006 conference, to appear
in a special issue of J. Phys.: Condens. Matte
Dynamics of the Current Account and Interest Differentials
In contrast to earlier work, we study the relation between the current account and interest rate differentials. To do so, we document the relation for international data. We then interpret this relation from a two-country, dynamic, general equilibrium environment. We finally confront the relation predicted by the environment to the relation observed in the data. We find that the environmental correctly predicts that the current account is countercyclical; that the interest differentials is procyclical; and that the current account is negatively correlated with current and future interest differentials, but positively correlated with past interest differentials.International real business cycle
Viscous fingering of miscible slices
Viscous fingering of a miscible high viscosity slice of fluid displaced by a
lower viscosity fluid is studied in porous media by direct numerical
simulations of Darcy's law coupled to the evolution equation for the
concentration of a solute controlling the viscosity of miscible solutions. In
contrast with fingering between two semi-infinite regions, fingering of finite
slices is a transient phenomenon due to the decrease in time of the viscosity
ratio across the interface induced by fingering and dispersion processes. We
show that fingering contributes transiently to the broadening of the peak in
time by increasing its variance. A quantitative analysis of the asymptotic
contribution of fingering to this variance is conducted as a function of the
four relevant parameters of the problem i.e. the log-mobility ratio R, the
length of the slice l, the Peclet number Pe and the ratio between transverse
and axial dispersion coefficients . Relevance of the results is
discussed in relation with transport of viscous samples in chromatographic
columns and propagation of contaminants in porous media.Comment: 10 pages, 13 figure
Modeling asteroid collisions and impact processes
As a complement to experimental and theoretical approaches, numerical
modeling has become an important component to study asteroid collisions and
impact processes. In the last decade, there have been significant advances in
both computational resources and numerical methods. We discuss the present
state-of-the-art numerical methods and material models used in "shock physics
codes" to simulate impacts and collisions and give some examples of those
codes. Finally, recent modeling studies are presented, focussing on the effects
of various material properties and target structures on the outcome of a
collision.Comment: Chapter to appear in the Space Science Series Book: Asteroids IV.
Includes minor correction
Small-body deflection techniques using spacecraft: techniques in simulating the fate of ejecta
We define a set of procedures to numerically study the fate of ejecta
produced by the impact of an artificial projectile with the aim of deflecting
an asteroid. Here we develop a simplified, idealized model of impact conditions
that can be adapted to fit the details of specific deflection-test scenarios,
such as what is being proposed for the AIDA project. Ongoing studies based upon
the methodology described here can be used to inform observational strategies
and safety conditions for an observing spacecraft. To account for ejecta
evolution, the numerical strategies we are employing are varied and include a
large N-Body component, a smoothed-particle hydrodynamics (SPH) component, and
an application of impactor scaling laws. Simulations that use SPH-derived
initial conditions show high-speed ejecta escaping at low angles of
inclination, and very slowly moving ejecta lofting off the surface at higher
inclination angles, some of which re-impacts the small-body surface. We are
currently investigating the realism of this and other models' behaviors. Next
steps will include the addition of solar perturbations to the model and
applying the protocol developed here directly to specific potential mission
concepts such as the proposed AIDA scenario.Comment: 19 pages, 11 figures, accepted for publication in Advances in Space
Research, Special Issue: Asteroids & Space Debri
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