Reference-dependent Preferences and the Transmission of Monetary Policy

This paper proposes a novel explanation of the vast empirical evidence showing that output and prices react asymmetrically to monetary policy innovations over contractions and expansions in the business cycle. We use VAR techniques to show that monetary policy exerts stronger e¤ects on the U.S. GDP during contractionary phases, as compared to expansionary ones. As to prices, their response is not statistically different across different cyclical stages. We show that these facts are consistent with a New Neoclassical Synthesis model based on the assumption that households' utility partly depends on deviations of their consumption from a reference level below which aversion to loss is displayed. In line with the theory developed by Kahneman and Tversky (1979), losses in consumption utility loom larger than gains. This implies state-dependent degrees of real rigidity and elasticity of intertemporal substitution in consumption that generate competing effects on the responses of output and inflation following a monetary innovation. The key predictions of the model are in line with the data. We then explore the state-dependent trade-off between inflation and output stabilization that naturally arises in this context. Greater elasticity of inflation to real activity during expansionary stages of the cycle promotes a stronger degree of policy activism in the response to the expected rate of inflation under discretion, compared to what is otherwise prescribed during contractions.Reference-dependent Preferences;Asymmetry;Monetary policy.

SiC(0001): a surface Mott-Hubbard insulator

We present ab-initio electronic structure calculations for the Si-terminated SiC(0001)$\sqrt{3}\times\sqrt{3}$ surface. While local density approximation (LDA) calculations predict a metallic ground state with a half-filled narrow band, Coulomb effects, included by the spin-polarized LDA+U method, result in a magnetic (Mott-Hubbard) insulator with a gap of 1.5 eV, comparable with the experimental value of 2.0 eV. The calculated value of the inter-site exchange parameter, J=30K, leads to the prediction of a paramagnetic Mott state, except at very low temperatures. The observed Si 2p surface core level doublet can naturally be explained as an on-site exchange splitting.Comment: RevTex, 4 pages, 4 eps-figure

Valence-bond states in dynamical Jahn-Teller molecular systems

We discuss a hopping model of electrons between idealized molecular sites with local orbital degeneracy and dynamical Jahn-Teller effect, for crystal field environments of sufficiently high symmetry. For the Mott-insulating case (one electron per site and large Coulomb repulsions), in the simplest two-fold degenerate situation, we are led to consider a particular exchange hamiltonian, describing two isotropic spin-1/2 Heisenberg problems coupled by a quartic term on equivalent bonds. This twin-exchange hamiltonian applies to a physical regime in which the inter-orbital singlet is the lowest-energy intermediate state available for hopping. This regime is favored by a relatively strong electron-phonon coupling. Using variational arguments, a large-N limit, and exact diagonalization data, we find that the ground state, in the one dimensional case, is a solid valence bond state. The situation in the two dimensional case is less clear. Finally, the behavior of the system upon hole doping is studied in one dimension.Comment: 11 pages, 5 figure

Iterative Approximate Consensus in the presence of Byzantine Link Failures

This paper explores the problem of reaching approximate consensus in synchronous point-to-point networks, where each directed link of the underlying communication graph represents a communication channel between a pair of nodes. We adopt the transient Byzantine link failure model [15, 16], where an omniscient adversary controls a subset of the directed communication links, but the nodes are assumed to be fault-free. Recent work has addressed the problem of reaching approximate consen- sus in incomplete graphs with Byzantine nodes using a restricted class of iterative algorithms that maintain only a small amount of memory across iterations [22, 21, 23, 12]. However, to the best of our knowledge, we are the first to consider approximate consensus in the presence of Byzan- tine links. We extend our past work that provided exact characterization of graphs in which the iterative approximate consensus problem in the presence of Byzantine node failures is solvable [22, 21]. In particular, we prove a tight necessary and sufficient condition on the underlying com- munication graph for the existence of iterative approximate consensus algorithms under transient Byzantine link model. The condition answers (part of) the open problem stated in [16].Comment: arXiv admin note: text overlap with arXiv:1202.609

Heterogeneous Catalytic Approaches in C-H Activation Reactions

This review summarizes the development of user-friendly, recyclable and easily separable heterogeneous catalysts for C–H activation during the last decade until December 2015

Development and commissioning of the ALICE pixel detector control system

The Silicon Pixel Detector (SPD) is the innermost detector of the ALICE Inner Tracking System and the closest one to the interaction point. In order to operate the detector in a safe way, a control system was developed in the framework of PVSS which allows to monitor and control a large number of parameters such as temperatures, currents, voltages, etc. The control system of the SPD implements interlock features to protect the detector against overheating and prevents operating it in case of malfunctions. The nearly 50,000 parameters required to fully configure the detector are stored in a database which employs automatic configuration versions after a new calibration run has been carried out. Several user interface panels were developed to allow experts and non-expert shifters to operate the detector in an easy and safe way. This contribution provides an overview of the SPD control system