Fleshing out the monetary transmission mechanism: output composition and the role of financial frictions

Financial frictions affect the way in which different components of GDP respond to a monetary policy shock. We embed the financial accelerator of Bernanke, Gertler and Gilchrist (1999) into a medium-scale Dynamic General Equilibrium model and evaluate the relative importance of financial frictions in explaining monetary transmission. Specifically, we match the impulse responses generated by the model with empirical impulse response functions obtained from a vector autoregression on US time series data. This allows us to provide estimates for the structural parameters of our model and judge the relevance of different model features. In addition, we propose a set of simple and instructive specification tests that can be used to assess the relative fit of various restricted models. Although our point estimates suggest some role for financial accelerator effects, they are actually of minor importance for the descriptive success of the model. JEL Classification: E32, E44, E51Financial Frictions, Minimum Distance Estimation, monetary policy, Output Composition

What accounts for the changes in U.S. fiscal policy transmission?

Using vector autoregressions on U.S. time series for 1957-1979 and 1983-2004, we find government spending shocks to have stronger effects on output, consumption, and wages in the earlier sample. We try to account for this observation within a DSGE model featuring price rigidities and limited asset market participation. Specifically, we estimate the structural parameters of the model for both samples by matching impulse responses. Model-based counterfactual experiments suggest that increased asset market participation accounts for some of the changes in fiscal transmission. However, the key quantitative factor appears to be the more active monetary policy of the Volcker-Greenspan period. JEL Classification: E21, E62, E63Asset Market Participation, DSGE, Fiscal Policy, government spending, Minimum Distance Estimation, monetary policy, Vector autoregression

SU(3) Landau gauge gluon and ghost propagators using the logarithmic lattice gluon field definition

We study the Landau gauge gluon and ghost propagators of SU(3) gauge theory, employing the logarithmic definition for the lattice gluon fields and implementing the corresponding form of the Faddeev-Popov matrix. This is necessary in order to consistently compare lattice data for the bare propagators with that of higher-loop numerical stochastic perturbation theory (NSPT). In this paper we provide such a comparison, and introduce what is needed for an efficient lattice study. When comparing our data for the logarithmic definition to that of the standard lattice Landau gauge we clearly see the propagators to be multiplicatively related. The data of the associated ghost-gluon coupling matches up almost completely. For the explored lattice spacings and sizes discretization artifacts, finite-size and Gribov-copy effects are small. At weak coupling and large momentum, the bare propagators and the ghost-gluon coupling are seen to be approached by those of higher-order NSPT.Comment: 18 pages, 19 figures, 5 table

Compact diode laser based light source with alternating dual-wavelength emission at 532 nm

Compact nonlinear frequency conversion of a Y-branch distributed Bragg reflector (DBR) diode laser for alternating dual-wavelength laser emission at 532 nm is presented for the very first time. The developed light source, realized on a 5 × 25 mm2 micro-optical bench, is based on single-pass second harmonic generation of a 1064 nm Y-branch DBR diode laser in a periodically poled lithium niobate waveguide crystal with superimposed poling periods. Phase-matching is obtained by intrinsic wavelength stabilization of the laser and wavelength tuning by implemented heater elements above the DBR gratings. Obtained optical output powers of 5.6 mW at 532.45 nm and 6.7 mW at 531.85 nm are limited by central lobe power contents of 52% available for waveguide coupling. With a spectral performance showing narrowband emission with spectral widths of 0.01 nm (0.4 cm−1) limited by the spectral resolution of the spectrum analyzer and a spectral spacing of 0.6 nm (20 cm−1), the developed light source is suitable for applications such as Raman spectroscopy and shifted excitation Raman difference spectroscopy (SERDS). Separate electrical contacts of the Y-branch diode laser enable alternating operation at both wavelengths

PPP-Persona : ein objektorientierter Multimedia-Präsentationsagent

In zukünftigen Benutzerschnittstellen werden zunehmend animierte Präsentationsagenten eingesetzt. Der am DFKI entwickelte Präsentationsagent PPP-Persona dient dazu, den Benutzer durch eine Hypermedia-Präsentation zu führen. Dank seiner objektorientierten Konzeption ist er jedoch auch für eine Vielzahl weiterer Anwendungen einsetzbar, wie beispielsweise Online-Hilfesysteme, Home-Shopping und Tele-Banking. Dem Paradigma der Client/Server-Architektur folgend, empfängt der PPP-Persona-Server Präsentationsaufgaben von einem Anwendungsprogramm, die dieser dann selbständig ausführt. Zur visuellen Realisierung des Präsentationsagenten kann sowohl auf Cartoon-Zeichungen als auch auf Videobildmaterial zurückgegriffen werden. Um die Präsentation lebendiger zu gestalten, kann PPP-Persona selbständig Animationssequenzen initiieren

Economic Impacts of a Premature Nuclear Phase-Out in Switzerland

This paper investigates the economic impacts of two policy proposals: "Strom ohne Atom" (SOA) and "Moratorium Plus" (MOP), both of which contain a premature phase-out of nuclear power in Switzerland. While MOP restricts business-as-usual operation time of existing nuclear power plants to 40 years, which results in a cutback of 10-20 years, SOA foresees a reduction in operation time of 20-30 years and administers combined heat and power to substitute for nuclear energy. Based onsimulations with an intertemporal multi-sector general equilibrium model of the Swiss economy, we quantify the price tags for risk reduction from nuclear power operation given additional constraints on back-up technologies. Costs of accelerating the phase-out of nuclear power for an average household amount to 200 CHF/a over the next 45 years under SOA and drop to 60 CHF/a in the case of MOP. If Switzerland were to assure carbon neutrality of a premature phase-out by the use of carbon taxes, adjustment costs would increase to 230 CHF under SOA and 110 CHF under MOP

HD 135344B: a young star has reached its rotational limit

We search for periodic variations in the radial velocity of the young Herbig star HD 135344B with the aim to determine a rotation period. We analyzed 44 high-resolution optical spectra taken over a time range of 151 days. The spectra were acquired with FEROS at the 2.2m MPG/ESO telescope in La Silla. The stellar parameters of HD 135344B are determined by fitting synthetic spectra to the stellar spectrum. In order to obtain radial velocity measurements, the stellar spectra have been cross-correlated with a theoretical template computed from determined stellar parameters. We report the first direct measurement of the rotation period of a Herbig star from radial-velocity measurements. The rotation period is found to be 0.16 d (3.9 hr), which makes HD 135344B a rapid rotator at or close to its break-up velocity. The rapid rotation could explain some of the properties of the circumstellar environment of HD 135344B such as the presence of an inner disk with properties (composition, inclination), that are significantly different from the outer disk.Comment: Accepted for publication in Astronomy & Astrophysics, 9 pages, 12 figure