Interaction of single molecules with metallic nanoparticles

We theoretically investigate the interaction between a single molecule and a metallic nanoparticle. We develop a general quantum mechanical description for the calculation of the enhancement of radiative and non-radiative decay channels for a molecule situated in the nearfield regime of the metallic nanoparticle. Using a boundary element method approach, we compute the scattering rates for several nanoparticle shapes. We also introduce an eigenmode expansion and quantization scheme for the surface plasmons, which allows us to analyze the scattering processes in simple physical terms. An intuitive explanation is given for the large quantum yield of quasi one- and two-dimensional nanostructures. Finally, we briefly discuss resonant Foerster energy transfer in presence of metallic nanoparticles.Comment: 12 pages, 4 figure

The DeepThought Core Architecture Framework

The research performed in the DeepThought project aims at demonstrating the potential of deep linguistic processing if combined with shallow methods for robustness. Classical information retrieval is extended by high precision concept indexing and relation detection. On the basis of this approach, the feasibility of three ambitious applications will be demonstrated, namely: precise information extraction for business intelligence; email response management for customer relationship management; creativity support for document production and collective brainstorming. Common to these applications, and the basis for their development is the XML-based, RMRS-enabled core architecture framework that will be described in detail in this paper. The framework is not limited to the applications envisaged in the DeepThought project, but can also be employed e.g. to generate and make use of XML standoff annotation of documents and linguistic corpora, and in general for a wide range of NLP-based applications and research purposes

High Precision Radial Velocity Measurements in the Infrared: A First Assessment of the RV Stability of CRIRES

High precision radial velocity (RV) measurements in the near infrared are on high demand, especially in the context of exoplanet search campaigns shifting their interest to late type stars in order to detect planets with ever lower mass or targeting embedded pre-main-sequence objects. ESO is offering a new spectrograph at the VLT -- CRIRES -- designed for high resolution near-infrared spectroscopy with a comparably broad wavelength coverage and the possibility to use gas-cells to provide a stable RV zero-point. We investigate here the intrinsic short-term RV stability of CRIRES, both with gas-cell calibration data and on-sky measurements using the absorption lines of the Earth's atmosphere imprinted in the source spectrum as a local RV rest frame. Moreover, we also investigate for the first time the intrinsic stability of telluric lines at 4100 nm for features originating in the lower troposphere. Our analysis of nearly 5 hours of consecutive observations of MS Vel, a M2II bright giant centred at two SiO first overtone band-heads at 4100 nm, demonstrates that the intrinsic short-term stability of CRIRES is very high, showing only a slow and fully compensateable drift of up to 60 m/s after 4.5 hours. The radial velocity of the telluric lines is constant down to a level of approx. +/- 10 m/s (or 7/1000 of one pixel). Utilising the same telluriclines as a rest frame for our radial velocity measurements of the science target, we obtain a constant RV with a precision of approx. +/- 20 m/s for MS Vel as expected for a M-giant.Comment: 12 pages, 6 figures, accepted by A&

Environmentally oriented energy policy and stock returns: an empirical analysis

This paper analyzes the effect of environmental regulation on stock returns (as a measure of economic performance) for German energy corporations. By using event study methodology, we consider the last minute victory of the acting government in the 2002 German federal elections to the Lower House of Parliament (Bundestag). The government coalition consisted of Social Democrats and the Green party and was generally associated with a paradigm shift in environmental and particularly energy policy towards the promotion of renewable energies and a phasing out of nuclear energy. In contrast, the opposing Christian Democrats and Liberal party signaled different priorities in line with traditional energy policy. Compared with other environmental event studies, we include insights from modern empirical finance and therefore also apply the Fama-French three-factor model to estimate the abnormal daily and monthly stock returns. The main estimation results of the empirical analysis imply (1) no evidence of a general negative impact of the 2002 Bundestag elections on stock returns for traditional utilities and (2) a positive albeit transitory short-run effect for the entire group of renewable energy corporations. We conclude that the 2002 Bundestag elections and therefore stringent environmental regulation had at least no general negative effect on the economic performance of energy corporations. One reason for this could be that the compliance costs of the government?s environmentally oriented energy policy were lower for traditional utilities than expected. --Environmental regulation,Energy policy,Nuclear energy,Renewable energies,Event study,CAPM,Market model,Three-factor model

Downward wage rigidity in Europe: A new flexible parametric approach and empirical results

We suggest a new parametric approach to estimate the extent of downward nominal wage rigidity in ten European countries between 1994 and 2001. The data base used throughout is the User Data Base (UDB) of the European Community Household Panel (ECHP). The proposed approach is based on the very flexible generalized hyperbolic distribution which allows to model wage change distributions characterized by thick tales, skewness and leptokurtosis. Significant downward nominal wage rigidity is found in all countries under analysis, but the extent varies considerably across countries. Yearly estimates reveal increasing rigidity in Italy, Greece and Portugal, while rigidity is declining in Denmark and Belgium. The results imply that the costs of price stability differ substantially across Europe. --

Analysing wage differences between the USA and Germany using proportional hazards models

We analyse differences between the wage distributions in the USA and Germany in 2001 both for women and men. The empirical analysis is based on the decomposition of differences using Cox's marginal (partial) likelihood. The approach based on rank invariant estimators such as Cox's is borrowed from the literature on failure time data. Donald et al. (2000) pioneered this approach. However, they did not use the full power of the semi-parametric approach. Instead, they argued for using a piecewise constant hazard rate model. We improve on their work by showing that the semi-parametric features of Cox's marginal likelihood are as appropriate for the analysis of wage decompositions and as easy to interpret. Moreover, we extend their approach by allowing for nonlinear regression effects. We will show empirically that this formulation will both increase the flexibility of their approach and improve the discriminatory power between wage regimes. --

LHC constraints on gauge boson couplings to dark matter

Collider searches for energetic particles recoiling against missing transverse energy allow to place strong bounds on the interactions between dark matter (DM) and standard model particles. In this article we update and extend LHC constraints on effective dimension-7 operators involving DM and electroweak gauge bosons. A concise comparison of the sensitivity of the mono-photon, mono-W, mono-Z, mono-W/Z, invisible Higgs-boson decays in the vector boson fusion mode and the mono-jet channel is presented. Depending on the parameter choices, either the mono-photon or the mono-jet data provide the most stringent bounds at the moment. We furthermore explore the potential of improving the current 8 TeV limits at 14 TeV. Future strategies capable of disentangling the effects of the different effective operators involving electroweak gauge bosons are discussed as well.Comment: 10 pages, 6 figures; v2: reconstruction efficiencies for the different missing transverse energy signals included in the analysis; version to appear in PR

Chirally enhanced corrections to FCNC processes in the generic MSSM

Chirally enhanced supersymmetric QCD corrections to FCNC processes are investigated in the framework of the MSSM with generic sources of flavor violation. These corrections arise from flavor-changing self-energy diagrams and can be absorbed into a finite renormalization of the squark-quark-gluino vertex. In this way enhanced two-loop and even three-loop diagrams can be efficiently included into a leading-order (LO) calculation. Our corrections substantially change the values of the parameters delta^{d,LL}_{23}, delta^{d,LR}_{23}, delta^{d,RL}_{23}, and delta^{d,RR}_{23} extracted from Br[B->X_s gamma] if tan(beta) is large. We find stronger (weaker) constraints compared to the LO result for negative (positive) values of mu. The constraints on delta^{d,LR,RL}_{13} and delta^{d,LR,RL}_{23} from B_d mixing and B_s mixing change drastically if the third-generation squark masses differ from those of the first two generations. K mixing is more strongly affected by the chirally enhanced loop diagrams and even sub-percent deviations from degenerate down and strange squark masses lead to profoundly stronger constraints on delta^{d,LR,RL}_{12}.Comment: 19 pages, 10 figure