Field testing of strategies for fire blight control in organic fruit growing

In organic fruit growing effective control strategies are needed to prevent blossom infections by the fire blight pathogen Erwinia amylovora. Many potential control agents are under discussion and have been tested in vitro and in vivo. 19 out of 27 tested preparations showed a high efficacy against E. amylovora in vitro. Nevertheless, on detached apple blossoms only 7 of them led to a symptom reduction by more than 50%. In six field trials conducted according to the EPPO guideline PP1/166(3) BlossomProtect (82%), Myco-sin (65%) and Funguran (58%) had the highest efficiency. In 2006 and 2007, strategies to integrate BlossomProtect in spray schedules of organic apple production have been tested. The use of sulphur or lime-sulphur before or after BlossomProtect did not influence the efficiency of BlossomProtect, which showed that fire blight control is possible without compromising apple scab control. The addition of Cutisan to BlossomProtect reduced fruit russet. An alternating use of BlossomProtect and Myco-sin was shown to be possible

Empirical evidence on inflation and unemployment in the long run

We examine the relationship between inflation and unemployment in the long run, using quarterly US data from 1952 to 2010. Using a band-pass filter approach, we find strong evidence that a positive relationship exists, where inflation leads unemployment by some 3 to 3 1/2 years, in cycles that last from 8 to 25 or 50 years. Our statistical approach is atheoretical in nature, but provides evidence in accordance with the predictions of Friedman (1977) and the recent New Monetarist model of Berentsen, Menzio, and Wright (2011): the relationship between inflation and unemployment is positive in the long run.Inflation, Unemployment, Long-Run Phillips Curve

Twisted-light-induced optical transitions in semiconductors: Free-carrier quantum kinetics

We theoretically investigate the interband transitions and quantum kinetics induced by light carrying orbital angular momentum, or twisted light, in bulk semiconductors. We pose the problem in terms of the Heisenberg equations of motion of the electron populations, and inter- and intra-band coherences. Our theory extends the free-carrier Semiconductor Bloch Equations to the case of photo-excitation by twisted light. The theory is formulated using cylindrical coordinates, which are better suited to describe the interaction with twisted light than the usual cartesian coordinates used to study regular optical excitation. We solve the equations of motion in the low excitation regime, and obtain analytical expressions for the coherences and populations; with these, we calculate the orbital angular momentum transferred from the light to the electrons and the paramagnetic and diamagnetic electric current densities.Comment: 11 pages, 3 figure

Non-invasive detection of molecular bonds in quantum dots

We performed charge detection on a lateral triple quantum dot with star-like geometry. The setup allows us to interpret the results in terms of two double dots with one common dot. One double dot features weak tunnel coupling and can be understood with atom-like electronic states, the other one is strongly coupled forming molecule-like states. In nonlinear measurements we identified patterns that can be analyzed in terms of the symmetry of tunneling rates. Those patterns strongly depend on the strength of interdot tunnel coupling and are completely different for atomic- or molecule-like coupled quantum dots allowing the non-invasive detection of molecular bonds.Comment: 4 pages, 4 figure

Photon heat transport in low-dimensional nanostructures

At low temperatures when the phonon modes are effectively frozen, photon transport is the dominating mechanism of thermal relaxation in metallic systems. Starting from a microscopic many-body Hamiltonian, we develop a nonequilibrium Green's function method to study energy transport by photons in nanostructures. A formally exact expression for the energy current between a metallic island and a one-dimensional electromagnetic field is obtained. From this expression we derive the quantized thermal conductance as well as show how the results can be generalized to nonequilibrium situations. Generally, the frequency-dependent current noise of the island electrons determines the energy transfer rate.Comment: 4 pages, 3 Fig

Kinetics of electron-positron pair plasmas using an adaptive Monte Carlo method

A new algorithm for implementing the adaptive Monte Carlo method is given. It is used to solve the relativistic Boltzmann equations that describe the time evolution of a nonequilibrium electron-positron pair plasma containing high-energy photons and pairs. The collision kernels for the photons as well as pairs are constructed for Compton scattering, pair annihilation and creation, bremsstrahlung, and Bhabha & Moller scattering. For a homogeneous and isotropic plasma, analytical equilibrium solutions are obtained in terms of the initial conditions. For two non-equilibrium models, the time evolution of the photon and pair spectra is determined using the new method. The asymptotic numerical solutions are found to be in a good agreement with the analytical equilibrium states. Astrophysical applications of this scheme are discussed.Comment: 43 pages, 7 postscript figures, to appear in the Astrophysical Journa

A verification library for multibody simulation software

A multibody dynamics verification library, that maintains and manages test and validation data is proposed, based on RRC Robot arm and CASE backhoe validation and a comparitive study of DADS, DISCOS, and CONTOPS that are existing public domain and commercial multibody dynamic simulation programs. Using simple representative problems, simulation results from each program are cross checked, and the validation results are presented. Functionalities of the verification library are defined, in order to automate validation procedure

Anomalous dephasing of bosonic excitons interacting with phonons in the vicinity of the Bose-Einstein condensation

The dephasing and relaxation kinetics of bosonic excitons interacting with a thermal bath of acoustic phonons is studied after coherent pulse excitation. The kinetics of the induced excitonic polarization is calculated within Markovian equations both for subcritical and supercritical excitation with respect to a Bose-Einstein condensation (BEC). For excited densities n below the critical density n_c, an exponential polarization decay is obtained, which is characterized by a dephasing rate G=1/T_2. This dephasing rate due to phonon scattering shows a pronounced exciton-density dependence in the vicinity of the phase transition. It is well described by the power law G (n-n_c)^2 that can be understood by linearization of the equations around the equilibrium solution. Above the critical density we get a non-exponential relaxation to the final condensate value p^0 with |p(t)|-|p^0| ~1/t that holds for all densities. Furthermore we include the full self-consistent Hartree-Fock-Bogoliubov (HFB) terms due to the exciton-exciton interaction and the kinetics of the anomalous functions F_k= . The collision terms are analyzed and an approximation is used which is consistent with the existence of BEC. The inclusion of the coherent x-x interaction does not change the dephasing laws. The anomalous function F_k exhibits a clear threshold behaviour at the critical density.Comment: European Physical Journal B (in print