Estimating the Costs and Benefits of EMU: The Impact of External Shocks on Labour Markets

Discussions of the economic costs and benefits of EMU usually take as their basis the optimum currency area (OCA) approach. This approach starts from the premise that when an external shock hits the economy, it is easier to adjust the exchange rate than domestic prices or wages. Most economists accept the general idea behind this approach, namely that nominal wages are usually sticky in the shortrun and that it is therefore easier to adjust to external shocks and obtain changes in the real exchange rate or the terms of trade through a movement in the exchange rate. But there is little agreement on how important these "external" shocks are in reality. We try to measure the importance of external shocks for (un)employment. We find that external shocks have little impact on unemployment, but are more important in the evolution of employment in manufacturing. The results differ, however, strongly from country to country and for about half of EU member countries we did not find any significant relationship. Taking into account various potential shock absorbers (exchange rate movements, fiscal and monetary policy) does not affect the results. We conclude that the loss of the exchange rate instrument will not lead to massive unemployment problems.exchange rates;export demand;external shocks;optimal currency area;(un)employment

Stochastic Cluster Series expansion for quantum spin systems

In this paper we develop a cluster-variant of the Stochastic Series expansion method (SCSE). For certain systems with longer-range interactions the SCSE is considerably more efficient than the standard implementation of the Stochastic Series Expansion (SSE), at low temperatures. As an application of this method we calculated the T=0-conductance for a linear chain with a (diagonal) next nearest neighbor interaction.Comment: 5 pages, 7 figure

Exact Diagonalization Dynamical Mean Field Theory for Multi-Band Materials: Effect of Coulomb correlations on the Fermi surface of Na_0.3CoO_2

Dynamical mean field theory combined with finite-temperature exact diagonalization is shown to be a suitable method to study local Coulomb correlations in realistic multi-band materials. By making use of the sparseness of the impurity Hamiltonian, exact eigenstates can be evaluated for significantly larger clusters than in schemes based on full diagonalization. Since finite-size effects are greatly reduced this approach allows the study of three-band systems down to very low temperatures, for strong local Coulomb interactions and full Hund exchange. It is also shown that exact diagonalization yields smooth subband quasi-particle spectra and self-energies at real frequencies. As a first application the correlation induced charge transfer between t2g bands in Na_0.3CoO_2 is investigated. For both Hund and Ising exchange the small eg' Fermi surface hole pockets are found to be slightly enlarged compared to the non-interacting limit, in agreement with previous Quantum Monte Carlo dynamical mean field calculations for Ising exchange, but in conflict with photoemission data.Comment: 9 pages, 7 figure

A foam model highlights the differences of the macro- and microrheology of respiratory horse mucus

Native horse mucus is characterized with micro- and macrorheology and compared to hydroxyethylcellulose (HEC) gel as a model. Both systems show comparable viscoelastic properties on the microscale and for the HEC the macrorheology is in good agreement with the microrheology. For the mucus, the viscoelastic moduli on the macroscale are several orders of magnitude larger than on the microscale. Large amplitude oscillatory shear experiments show that the mucus responds nonlinearly at much smaller deformations than HEC. This behavior fosters the assumption that the mucus has a foam like structure on the microscale compared to the typical mesh like structure of the HEC, a model that is supported by cryogenic-scanning-electron-microscopy (CSEM) images. These images allow also to determine the relative amount of volume that is occupied by the pores and the scaffold. Consequently, we can estimate the elastic modulus of the scaffold. We conclude that this particular foam like microstructure should be considered as a key factor for the transport of particulate matter which plays a central role in mucus function with respect to particle penetration. The mesh properties composed of very different components are responsible for macroscopic and microscopic behavior being part of particles fate after landing.Comment: Accepted for publication in the Journal of the Mechanical Behavior of Biomedical Material

A Variational Monte Carlo Study of the Current Carried by a Quasiparticle

With the use of Gutzwiller-projected variational states, we study the renormalization of the current carried by the quasiparticles in high-temperature superconductors and of the quasiparticle spectral weight. The renormalization coefficients are computed by the variational Monte Carlo technique, under the assumption that quasiparticle excitations may be described by Gutzwiller-projected BCS quasiparticles. We find that the current renormalization coefficient decreases with decreasing doping and tends to zero at zero doping. The quasiparticle spectral weight Z_+ for adding an electron shows an interesting structure in k space, which corresponds to a depression of the occupation number k just outside the Fermi surface. The perturbative corrections to those quantities in the Hubbard model are also discussed.Comment: 9 pages, 9 figure

Imaging extended sources with coded mask telescopes: Application to the INTEGRAL IBIS/ISGRI instrument

Context. In coded mask techniques, reconstructed sky images are pseudo-images: they are maps of the correlation between the image recorded on a detector and an array derived from the coded mask pattern. Aims. The INTEGRAL/IBIS telescope provides images where the flux of each detected source is given by the height of the local peak in the correlation map. As such, it cannot provide an estimate of the flux of an extended source. What is needed is intensity sky images giving the flux per solide angle as typically done at other wavelengths. Methods. In this paper, we present the response of the INTEGRAL IBIS/ISGRI coded mask instrument to extended sources. We develop a general method based on analytical calculations in order to measure the intensity and the associated error of any celestial source and validated with Monte-Carlo simulations. Results. We find that the sensitivity degrades almost linearly with the source extent. Analytical formulae are given as well as an easy-to-use recipe for the INTEGRAL user. We check this method on IBIS/ISGRI data but these results are general and applicable to any coded mask telescope.Comment: 9 pages, 6 figures, Accepted for publication in A&

Strong intracellular signal inactivation produces sharper and more robust signaling from cell membrane to nucleus

For a chemical signal to propagate across a cell, it must navigate a tortuous environment involving a variety of organelle barriers. In this work we study mathematical models for a basic chemical signal, the arrival times at the nuclear membrane of proteins that are activated at the cell membrane and diffuse throughout the cytosol. Organelle surfaces within human B cells are reconstructed from soft X-ray tomographic images, and modeled as reflecting barriers to the molecules’ diffusion. We show that signal inactivation sharpens signals, reducing variability in the arrival time at the nuclear membrane. Inactivation can also compensate for an observed slowdown in signal propagation induced by the presence of organelle barriers, leading to arrival times at the nuclear membrane that are comparable to models in which the cytosol is treated as an open, empty region. In the limit of strong signal inactivation this is achieved by filtering out molecules that traverse non-geodesic paths.https://www.biorxiv.org/content/10.1101/2020.01.16.909333v1First author draf