Red Signals: Trade Deficits and the Current Account

This paper proposes a method to asses the potential problems of sustainability of a country’s sovereign debt. We claim that the relevant variables used for this analysis are typically subject to changes which are associated with changes in macroeconomics policies. We propose a procedure for identifying periods under which the trade deficit and the current account accumulate at a nonstationary rate. Our approach is based on imposing identifying restrictions on Markov switching type models. An empirical application of the procedure to UK data is examined and discussed. We find that periods of non-stationary trade deficits typically coincide with current account crises

Testing the Unbiased Forward Exchange Rate Hypothesis Using a Markov Switching Model and Instrumental Variables

This paper develops a model for the forward and spot exchange rate which allows for the presence of a Markov switching risk premium in the forward market and considers the issue of testing for the unbiased forward exchange rate (UFER) hypothesis. Using US/UK data, it is shown that the UFER hypothesis cannot be rejected provided that instrumental variables are used to account for within-regime correlation between explanatory variables and disturbances in the Markov switching model on which the test is based

A test for volatility spillovers

This paper proposes a new procedure for analyzing volatility links between di®erent markets based on a bivariate Markov switching model. An empirical application of this procedure to three emerging markets is examined and discussed

Contemporaneous-threshold smooth transition GARCH models

This paper proposes a contemporaneous-threshold smooth transition GARCH (or C-STGARCH)model for dynamic conditional heteroskedasticity. The C-STGARCH model is a generalization tosecond conditional moments of the contemporaneous smooth transition threshold autoregressive model of Dueker et al. (2007) in which the regime weights depend on the ex ante probability that a contemporaneous latent regime-specific variable exceeds a threshold value. A key feature of the C-STGARCH model is that its transition function depends on all the parameters of the model as well as on the data. The structural properties of the model are investigated, in addition to the finite-sample properties of the maximum likelihood estimator of its parameters. An application to U.S. stock returns illustrates the practical usefulness of the C-STGARCH model

The effects of different parameterizations of Markov-switching in a CIR model of bond pricing

We examine several discrete-time versions of the Cox, Ingersoll and Ross (CIR) model for the term structure, in which the short rate is subject to discrete shifts. Our empirical analysis suggests that careful consideration of which parameters of the short-term interest rate equation that are allowed to be switched is crucial. Ignoring this issue may result in a parameterization that produces no improvement (in terms of bond pricing) relative to the standard CIR model, even when there are clear breaks in the data

Mariner Mars 1971 spacecraft destruct unit

Shaped charge destruct unit for Mariner Mars 1971 spacecraf

The anomaly-induced effective action and natural inflation

The anomaly-induced inflation (modified Starobinsky model) is based on the application of the effective quantum field theory approach to the Early Universe. We present a brief general review of the model and show that it does not require a fine-tuning for the parameters of the theory or initial data, gives a real chance to meet a graceful exit to the FRW phase and also has positive features with respect to the metric perturbations.Comment: Invited talk at the International Workshop on Astroparticle and High Energy Physics, October 14 - 18, 2003, Valencia, Spai

Variable kinematics layerwise model for analysis of bonded joints

A displacement-based multi-layered zig-zag plate model with variable in-plane and through-the-thickness representation and fixed degrees of freedom is developed for analysis of bonded joints with laminated adherents. Characteristic feature, the in-plane representation can be varied across the adherents and the overlap to better simulate the variation of solutions and to satisfy the stress boundary conditions at the ends of the overlap. To this purpose, continuity functions are incorporated enabling the continuity of displacements and stresses where the representation is changed. Other continuity functions are included to allow an a priori fulfillment of the out-of-plane stress contact conditions at the interfaces of adjacent layers. High-order, through-the-thickness contributions are incorporated allowing the representation to be refined where step gradients rise. As the representation can vary from point to point, the present model permits an accurate analysis of laminates with general boundary conditions and of bonded joints under a unified approach. Applications are presented to sample cases of single- and double-lap joints taken from the literature. Specifically, three single-lap joints are considered, two of which with aluminum adherents and one with laminated composite adherents. Also a double-lap joint with aluminum adherents is analyzed. The numerical results show that accurate stress predictions are obtained with a low computational effort in all the cases considered using appropriate series expansions of displacements. The accuracy is good even using a single component in the expansion, which implies solving a 3x3 system

On the Running of the Cosmological Constant in Quantum General Relativity

We present arguments that show what the running of the cosmological constant means when quantum general relativity is formulated following the prescription developed by Feynman.Comment: 5 page

Indentation of Sandwiches Using a Refined Zig-Zag Model and a Mesoscale Damage Model

An accurate and cost effective zig-zag plate model with variable kinematics and fixed degrees of freedom recently developed by the authors, which a priori fulfills the stress and displacement continuity requirements, is applied to study indentation of sandwiches with honeycomb/foam core. The variable elastic properties of the core during crushing are evaluated apart and once at a time through a 3D finite element analysis. Shell elements with elastic-plastic isotropic properties are adopted to discretize honeycomb cores and faces, instead solid elements with nonlinear material behavior are used for foam cores. To keep low the computational burden, the structural response is computed in closed form by the zig-zag model using these elastic properties. The damage analysis is carried out through a mesoscale model that determines the degraded properties of failed regions in a physically consistent way. A good agreement with experiments taken from the literature being shown, the present simulation procedure with a low computational effort is proven to be an efficient alternative to the ones currently employed