5,817 research outputs found
Using parallel computation to improve Independent Metropolis--Hastings based estimation
In this paper, we consider the implications of the fact that parallel
raw-power can be exploited by a generic Metropolis--Hastings algorithm if the
proposed values are independent. In particular, we present improvements to the
independent Metropolis--Hastings algorithm that significantly decrease the
variance of any estimator derived from the MCMC output, for a null computing
cost since those improvements are based on a fixed number of target density
evaluations. Furthermore, the techniques developed in this paper do not
jeopardize the Markovian convergence properties of the algorithm, since they
are based on the Rao--Blackwell principles of Gelfand and Smith (1990), already
exploited in Casella and Robert (1996), Atchade and Perron (2005) and Douc and
Robert (2010). We illustrate those improvements both on a toy normal example
and on a classical probit regression model, but stress the fact that they are
applicable in any case where the independent Metropolis-Hastings is applicable.Comment: 19 pages, 8 figures, to appear in Journal of Computational and
Graphical Statistic
Inflation Persistence and the Taylor Principle
Although the persistence of inflation is a central concern of macroeconomics, there is no consensus regarding whether or not inflation is stationary or has a unit root. We show that, in the context of a âtextbookâ macroeconomic model, inflation is stationary if and only if the Taylor rule obeys the Taylor principle, so that the real interest rate is increased when inflation rises above the target inflation rate. We estimate Markov switching models for both inflation and real-time forward looking Taylor rules. Inflation appears to have a unit root for most of the 1967 â 1981 period, and is stationary before 1967 and after 1981. We find that the Fedâs response to inflation is also regime dependent, with both the pre and post-Volcker samples containing monetary regimes where the Fed both did and did not follow the Taylor principle. This contrasts to recent research that suggests the Fedâs response to inflation has been time invariant, and that changes in monetary policy only occurred with respect to the output gap.Taylor rule, real-time data, Great inflation, policy regimes, Markov switching
Constant Mean Curvature 1/2 Surfaces in H2 Ă R
This thesis lies in the field of constant mean curvature (cmc) hypersurfaces and specifically cmc 1/2 surfaces in the three-manifold H 2 à R. The value 1/2 is the critical mean curvature for H 2 à R, in that there do no exist closed cmc surfaces with mean curvature 1/2 or less. Daniel and Hauswirth have constructed a one-parameter family of complete, cmc 1/2 annuli that are symmetric about a reflection in the horizontal place H 2 à {0}, the horizontal catenoids. In this thesis we prove that these catenoids converge to a singular limit of two tangent horocylinders as the neck size tends to zero. We discuss the analytic gluing construction that this fact suggests, which would create a multitude of cmc 1/2 surfaces with positive genus. The main result of the thesis concerns a key step in such an analytic gluing construction. We construct families of cmc 1/2 annuli with boundary, whose single end is asymptotic to an end of a horizontal catenoid. We produce these families by solving the mean curvature equation for normal graphs off the end of a horizontal catenoid. This is a non-linear boundary value problem, which we solve by perturbative methods. To do so we analyse the linearised mean curvature operator, known as the Jacobi operator. We show that on carefully chosen weighted Hšolder spaces the Jacobi operator can be inverted, modulo a finite-dimensional subspace, and provided the neck size of the horizontal catenoid is sufficiently small. Using these linear results we solve the boundary value problem for the mean curvature equation by a contraction mapping argument
College mental health access
Abstract Objective: Analyze the effects of having accessible mental health care access for undergraduate students. Design: Nonexperimental, Comparative Setting: Fort Hays Health Science College Participants: Fort Hays undergraduate health sciences students Conclusion: Depending on the results and data collectio
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